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Sample records for autophagy regulates adipose

  1. Altered autophagy in human adipose tissues in obesity

    Science.gov (United States)

    Context: Autophagy is a housekeeping mechanism, involved in metabolic regulation and stress response, shown recently to regulate lipid droplets biogenesis/breakdown and adipose tissue phenotype. Objective: We hypothesized that in human obesity autophagy may be altered in adipose tissue in a fat d...

  2. Autophagy activity is up-regulated in adipose tissue of obese individuals and modulates proinflammantory cytokine expression.

    NARCIS (Netherlands)

    Jansen, H.J.; Essen, van P.; Koenen, T.; Joosten, L.A.; Netea, M.G.; Tack, C.J.; Stienstra, R.

    2012-01-01

    Autophagy, an evolutionary conserved process aimed at recycling damaged organelles and protein aggregates in the cell, also modulates proinflammatory cytokine production in peripheral blood mononuclear cells. Because adipose tissue inflammation accompanied by elevated levels of proinflammatory cytok

  3. Autophagy activity is up-regulated in adipose tissue of obese individuals and modulates proinflammatory cytokine expression

    NARCIS (Netherlands)

    Jansen, H.J.; Essen, P. van; Koenen, T.; Joosten, L.A.B.; Netea, M.G.; Tack, C.J.J.; Stienstra, R.

    2012-01-01

    Autophagy, an evolutionary conserved process aimed at recycling damaged organelles and protein aggregates in the cell, also modulates proinflammatory cytokine production in peripheral blood mononuclear cells. Because adipose tissue inflammation accompanied by elevated levels of proinflammatory cytok

  4. Weight Loss Upregulates the Small GTPase DIRAS3 in Human White Adipose Progenitor Cells, Which Negatively Regulates Adipogenesis and Activates Autophagy via Akt-mTOR Inhibition.

    Science.gov (United States)

    Ejaz, Asim; Mitterberger, Maria C; Lu, Zhen; Mattesich, Monika; Zwierzina, Marit E; Hörl, Susanne; Kaiser, Andreas; Viertler, Hans-Peter; Rostek, Ursula; Meryk, Andreas; Khalid, Sana; Pierer, Gerhard; Bast, Robert C; Zwerschke, Werner

    2016-04-01

    Long-term weight-loss (WL) interventions reduce insulin serum levels, protect from obesity, and postpone age-associated diseases. The impact of long-term WL on adipose-derived stromal/progenitor cells (ASCs) is unknown. We identified DIRAS3 and IGF-1 as long-term WL target genes up-regulated in ASCs in subcutaneous white adipose tissue of formerly obese donors (WLDs). We show that DIRAS3 negatively regulates Akt, mTOR and ERK1/2 signaling in ASCs undergoing adipogenesis and acts as a negative regulator of this pathway and an activator of autophagy. Studying the IGF-1-DIRAS3 interaction in ASCs of WLDs, we demonstrate that IGF-1, although strongly up-regulated in these cells, hardly activates Akt, while ERK1/2 and S6K1 phosphorylation is activated by IGF-1. Overexpression of DIRAS3 in WLD ASCs completely inhibits Akt phosphorylation also in the presence of IGF-1. Phosphorylation of ERK1/2 and S6K1 is lesser reduced under these conditions. In conclusion, our key findings are that DIRAS3 down-regulates Akt-mTOR signaling in ASCs of WLDs. Moreover, DIRAS3 inhibits adipogenesis and activates autophagy in these cells. PMID:27211557

  5. Regulation of Autophagy by Kinases

    Energy Technology Data Exchange (ETDEWEB)

    Sridharan, Savitha; Jain, Kirti; Basu, Alakananda, E-mail: alakananda.basu@unthsc.edu [Department of Molecular Biology and Immunology, Institute for Cancer Research, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States)

    2011-06-09

    Autophagy is a process of self-degradation that maintains cellular viability during periods of metabolic stress. Although autophagy is considered a survival mechanism when faced with cellular stress, extensive autophagy can also lead to cell death. Aberrations in autophagy are associated with several diseases, including cancer. Therapeutic exploitation of this process requires a clear understanding of its regulation. Although the core molecular components involved in the execution of autophagy are well studied there is limited information on how cellular signaling pathways, particularly kinases, regulate this complex process. Protein kinases are integral to the autophagy process. Atg1, the first autophagy-related protein identified, is a serine/threonine kinase and it is regulated by another serine/threonine kinase mTOR. Emerging studies suggest the participation of many different kinases in regulating various components/steps of this catabolic process. This review focuses on the regulation of autophagy by several kinases with particular emphasis on serine/threonine protein kinases such as mTOR, AMP-activated protein kinase, Akt, mitogen-activated protein kinase (ERK, p38 and JNK) and protein kinase C that are often deregulated in cancer and are important therapeutic targets.

  6. Feedback regulation between autophagy and PKA.

    Science.gov (United States)

    Torres-Quiroz, Francisco; Filteau, Marie; Landry, Christian R

    2015-01-01

    Protein kinase A (PKA) controls diverse cellular processes and homeostasis in eukaryotic cells. Many processes and substrates of PKA have been described and among them are direct regulators of autophagy. The mechanisms of PKA regulation and how they relate to autophagy remain to be fully understood. We constructed a reporter of PKA activity in yeast to identify genes affecting PKA regulation. The assay systematically measures relative protein-protein interactions between the regulatory and catalytic subunits of the PKA complex in a systematic set of genetic backgrounds. The candidate PKA regulators we identified span multiple processes and molecular functions (autophagy, methionine biosynthesis, TORC signaling, protein acetylation, and DNA repair), which themselves include processes regulated by PKA. These observations suggest the presence of many feedback loops acting through this key regulator. Many of the candidate regulators include genes involved in autophagy, suggesting that not only does PKA regulate autophagy but that autophagy also sends signals back to PKA.

  7. Molecular mechanism and regulation of autophagy

    Institute of Scientific and Technical Information of China (English)

    Ya-ping YANG; Zhong-qin LIANG; Zhen-lun GU; Zheng-hong QIN

    2005-01-01

    Autophagy is a major cellular pathway for the degradation of long-lived proteins and cytoplasmic organelles in eukaryotic cells. A large number of intracellular/extracellular stimuli, including amino acid starvation and invasion of microorganisms, are able to induce the autophagic response in cells. The discovery of the ATG genes in yeast has greatly advanced our understanding of the molecular mechanisms participating in autophagy and the genes involved in regulating the autophagic pathway. Many yeast genes have mammalian homologs,suggesting that the basic machinery for autophagy has been evolutionarily conserved along the eukaryotic phylum. The regulation of autophagy is a very complex process. Many signaling pathways, including target of rapamycin (TOR) or mammalian target of rapamycin (mTOR), phosphatidylinositol 3-kinase-I (PI3K-I)/PKB, GTPases, calcium and protein synthesis all play important roles in regulating autophagy. The molecular mechanisms and regulation of autophagy are discussed in this review.

  8. Autophagy in immune cell regulation and dysregulation.

    Science.gov (United States)

    Chaturvedi, Akanksha; Pierce, Susan K

    2009-09-01

    Autophagy is an ancient pathway required for cell and tissue homeostasis and differentiation. Initially thought to be a process leading to cell death, autophagy is currently viewed as a beneficial catabolic process that promotes cell survival under starvation conditions by sequestering components of the cytoplasm, including misfolded proteins, protein aggregates, and damaged organelles, and targeting them for lysosome-mediated degradation. In this way, autophagy plays a role in maintaining a balance between degradation and recycling of cellular material. The importance of autophagy is underscored by the fact that malfunctioning of this pathway results in neurodegeneration, cancer, susceptibility to microbial infection, and premature aging. Autophagy occurs in almost all cell types, including immune cells. Recent advances in the field suggest that autophagy plays a central role in regulating the immune system at multiple levels. In this review, we focus on recent developments in the area of autophagy-mediated modulation of immune responses. PMID:19671376

  9. FGF signalling regulates bone growth through autophagy.

    Science.gov (United States)

    Cinque, Laura; Forrester, Alison; Bartolomeo, Rosa; Svelto, Maria; Venditti, Rossella; Montefusco, Sandro; Polishchuk, Elena; Nusco, Edoardo; Rossi, Antonio; Medina, Diego L; Polishchuk, Roman; De Matteis, Maria Antonietta; Settembre, Carmine

    2015-12-10

    Skeletal growth relies on both biosynthetic and catabolic processes. While the role of the former is clearly established, how the latter contributes to growth-promoting pathways is less understood. Macroautophagy, hereafter referred to as autophagy, is a catabolic process that plays a fundamental part in tissue homeostasis. We investigated the role of autophagy during bone growth, which is mediated by chondrocyte rate of proliferation, hypertrophic differentiation and extracellular matrix (ECM) deposition in growth plates. Here we show that autophagy is induced in growth-plate chondrocytes during post-natal development and regulates the secretion of type II collagen (Col2), the major component of cartilage ECM. Mice lacking the autophagy related gene 7 (Atg7) in chondrocytes experience endoplasmic reticulum storage of type II procollagen (PC2) and defective formation of the Col2 fibrillary network in the ECM. Surprisingly, post-natal induction of chondrocyte autophagy is mediated by the growth factor FGF18 through FGFR4 and JNK-dependent activation of the autophagy initiation complex VPS34-beclin-1. Autophagy is completely suppressed in growth plates from Fgf18(-/-) embryos, while Fgf18(+/-) heterozygous and Fgfr4(-/-) mice fail to induce autophagy during post-natal development and show decreased Col2 levels in the growth plate. Strikingly, the Fgf18(+/-) and Fgfr4(-/-) phenotypes can be rescued in vivo by pharmacological activation of autophagy, pointing to autophagy as a novel effector of FGF signalling in bone. These data demonstrate that autophagy is a developmentally regulated process necessary for bone growth, and identify FGF signalling as a crucial regulator of autophagy in chondrocytes. PMID:26595272

  10. Skeletal Muscle Autophagy: A New Metabolic Regulator

    OpenAIRE

    Neel, Brian A.; Lin, Yuxi; Pessin, Jeffrey E.

    2013-01-01

    Autophagy classically functions as a physiological process to degrade cytoplasmic components, protein aggregates, and/or organelles, as a mechanism for nutrient breakdown, and as a regulator of cellular architecture. Proper autophagic flux is vital for both functional skeletal muscle, which controls support and movement of the skeleton, and muscle metabolism. The role of autophagy as a metabolic regulator in muscle has been previously studied; however, the underlying molecular mechanisms that...

  11. Autophagy: Regulation by Energy Sensing

    NARCIS (Netherlands)

    A.J. Meijer; P. Codogno

    2011-01-01

    Autophagy is inhibited by the mTOR signaling pathway, which is stimulated by increased amino acid levels. When cellular energy production is compromised, AMP-activated protein kinase is activated, mTOR is inhibited and autophagy is stimulated. Two recent studies have shed light on the molecular mech

  12. MicroRNA regulation of Autophagy

    DEFF Research Database (Denmark)

    Frankel, Lisa B; Lund, Anders H

    2012-01-01

    Macroautophagy (hereafter referred to as autophagy) is a tightly regulated intracellular catabolic pathway involving the lysosomal degradation of cytoplasmic organelles and proteins. Central to this process is the formation of the autophagosome, a double membrane-bound vesicle, which is responsible...... for the delivery of cytoplasmic cargo to the lysosomes. Autophagy levels are constantly changing, allowing adaptation to both immediate and long-term needs of the cell, underlining why tight control of this process is essential in order to prevent the development of pathological disorders. Substantial progress has...... recently contributed to our understanding of the molecular mechanisms of the autophagy machinery, yet several gaps remain in our knowledge of this process. The discovery of microRNAs (miRNAs) established a new paradigm of post-transcriptional gene regulation and during the past decade these small non...

  13. Autophagy activator promotes neuronal differentiation of adult adipose-derived stromal cells

    Institute of Scientific and Technical Information of China (English)

    Yanhui Lu; Xiaodong Yuan; Qiaoyu Sun; Ya Ou

    2013-01-01

    Preliminary research from our group found altered autophagy intensity during adipose-derived stromal cell differentiation into neuronal-like cells, and that this change was associated with morphological changes in differentiated cells. This study aimed to verify the role of rapamycin, an autophagy activator, in the process of adipose-derived stromal cell differentiation into neuronal-like cells. Immunohistochemical staining showed that expression of neuron-specific enolase and neurofilament-200 were gradually upregulated in adipose-derived stromal cells after 5 mM β-mercaptoethanol induction, and the differentiation rate gradually increased with induction time. Using transmission electron microscopy, induced cells were shown to exhibit cytoplasmic autophagosomes, with bilayer membranes, and autolysosomes. After rapamycin (200μg/L) induction for 1 hour, adipose-derived stromal cells began to extend long processes, similar to the morphology of neuronal-like cells, while untreated cells did not exhibit similar morphologies until 3 hours after induction. Moreover, the differentiation rate was significantly increased after rapamycin treatment. Compared with untreated cells, expression of LC3, an autophagy protein, was also significantly upregulated. Positive LC3 expression tended to concentrate at cell nuclei with increasing induction times. Our experimental findings indicate that autophagy can significantly increase the speed of adipose-derived stromal cell differentiation into neuronal-like cells.

  14. Exercise regulation of adipose tissue.

    Science.gov (United States)

    Stanford, Kristin I; Goodyear, Laurie J

    2016-01-01

    Exercise training results in adaptations to numerous organ systems and offers protection against metabolic disorders including obesity and type 2 diabetes, and recent reports suggest that adipose tissue may play a role in these beneficial effects of exercise on overall health. Multiple studies have investigated the effects of exercise training on both white adipose tissue (WAT) and brown adipose tissue (BAT), as well as the induction of beige adipocytes. Studies from both rodents and humans show that there are exercise training-induced changes in WAT including decreased cell size and lipid content, and increased mitochondrial activity. In rodents, exercise training causes an increased beiging of WAT. Whether exercise training causes a beiging of human scWAT, as well as which factors contribute to the exercise-induced beiging of WAT are areas of current investigation. Studies investigating the effects of exercise training on BAT mass and function have yielded conflicting data, and hence, is another area of intensive investigation. This review will focus on studies aimed at elucidating the mechanisms regulating exercise training induced-adaptations to adipose tissue. PMID:27386159

  15. Bone Cell Autophagy Is Regulated by Environmental Factors

    OpenAIRE

    Zahm, Adam M.; Bohensky, Jolene; Adams, Christopher S.; Shapiro, Irving M.; Srinivas, Vickram

    2011-01-01

    The goal of this investigation was to ascertain whether bone cells undergo autophagy and to determine if this process is regulated by environmental factors. We showed that osteocytes in both murine and human cortical bone display a punctuate distribution of microtubule-associated protein light chain 3, indicative of autophagy. In addition, we noted a basal level of autophagy in preosteocyte-like murine long bone-derived osteocytic (MLO)-A5 cells. Autophagy was upregulated following nutrient d...

  16. Regulation of autophagy by nucleoporin Tpr.

    Science.gov (United States)

    Funasaka, Tatsuyoshi; Tsuka, Eriko; Wong, Richard W

    2012-01-01

    The nuclear pore complex (NPC) consists of a conserved set of ~30 different proteins, termed nucleoporins, and serves as a gateway for the exchange of materials between the cytoplasm and nucleus. Tpr (translocated promoter region) is a component of NPC that presumably localizes at intranuclear filaments. Here, we show that Tpr knockdown caused a severe reduction in the number of nuclear pores. Furthermore, our electron microscopy studies indicated a significant reduction in the number of inner nuclear filaments. In addition, Tpr siRNA treatment impaired cell growth and proliferation compared to control siRNA-treated cells. In Tpr-depleted cells, the levels of p53 and p21 proteins were enhanced. Surprisingly, Tpr depletion increased p53 nuclear accumulation and facilitated autophagy. Our study demonstrates for the first time that Tpr plays a role in autophagy through controlling HSP70 and HSF1 mRNA export, p53 trafficking with karyopherin CRM1, and potentially through direct transcriptional regulation of autophagy factors.

  17. Role of autophagy in the regulation of epithelial cell junctions.

    Science.gov (United States)

    Nighot, Prashant; Ma, Thomas

    2016-01-01

    Autophagy is a cell survival mechanism by which bulk cytoplasmic material, including soluble macromolecules and organelles, is targeted for lysosomal degradation. The role of autophagy in diverse cellular processes such as metabolic stress, neurodegeneration, cancer, aging, immunity, and inflammatory diseases is being increasingly recognized. Epithelial cell junctions play an integral role in the cell homeostasis via physical binding, regulating paracellular pathways, integrating extracellular cues into intracellular signaling, and cell-cell communication. Recent data indicates that cell junction composition is very dynamic. The junctional protein complexes are actively regulated in response to various intra- and extra-cellular clues by intracellular trafficking and degradation pathways. This review discusses the recent and emerging information on how autophagy regulates various epithelial cell junctions. The knowledge of autophagy regulation of epithelial junctions will provide further rationale for targeting autophagy in a wide variety of human disease conditions. PMID:27583189

  18. Regulation of autophagy in oxygen-dependent cellular stress.

    Science.gov (United States)

    Ryter, Stefan W; Choi, Augustine M K

    2013-01-01

    Oxidative stress caused by supraphysiological production of reactive oxygen species (ROS), can cause cellular injury associated with protein and lipid oxidation, DNA damage, and mitochondrial dysfunction. The cellular responses triggered by oxidative stress include the altered regulation of signaling pathways that culminate in the regulation of cell survival or cell death pathways. Recent studies suggest that autophagy, a cellular homeostatic process that governs the turnover of damaged organelles and proteins, may represent a general cellular and tissue response to oxidative stress. The autophagic pathway involves the encapsulation of substrates in double-membraned vesicles, which are subsequently delivered to the lysosome for enzymatic degradation and recycling of metabolic precursors. Autophagy may play multifunctional roles in cellular adaptation to stress, by maintaining mitochondrial integrity, and removing damaged proteins. Additionally, autophagy may play important roles in the regulation of inflammation and immune function. Modulation of the autophagic pathway has been reported in cell culture models of oxidative stress, including altered states of oxygen tension (i.e., hypoxia, hyperoxia), and exposure to oxidants. Furthermore, proteins that regulate autophagy may be subject to redox regulation. The heme oxygenase- 1 (HO)-1 enzyme system may have a role in the regulation of autophagy. Recent studies suggest that carbon monoxide (CO), a reaction product of HO activity which can alter mitochondrial function, may induce autophagy in cultured epithelial cells. In conclusion, current research suggests a central role for autophagy as a mammalian oxidative stress response and its interrelationship to other stress defense systems. PMID:23092322

  19. The Mucosal Immune System and Its Regulation by Autophagy.

    Science.gov (United States)

    Kabat, Agnieszka M; Pott, Johanna; Maloy, Kevin J

    2016-01-01

    The gastrointestinal tract presents a unique challenge to the mucosal immune system, which has to constantly monitor the vast surface for the presence of pathogens, while at the same time maintaining tolerance to beneficial or innocuous antigens. In the intestinal mucosa, specialized innate and adaptive immune components participate in directing appropriate immune responses toward these diverse challenges. Recent studies provide compelling evidence that the process of autophagy influences several aspects of mucosal immune responses. Initially described as a "self-eating" survival pathway that enables nutrient recycling during starvation, autophagy has now been connected to multiple cellular responses, including several aspects of immunity. Initial links between autophagy and host immunity came from the observations that autophagy can target intracellular bacteria for degradation. However, subsequent studies indicated that autophagy plays a much broader role in immune responses, as it can impact antigen processing, thymic selection, lymphocyte homeostasis, and the regulation of immunoglobulin and cytokine secretion. In this review, we provide a comprehensive overview of mucosal immune cells and discuss how autophagy influences many aspects of their physiology and function. We focus on cell type-specific roles of autophagy in the gut, with a particular emphasis on the effects of autophagy on the intestinal T cell compartment. We also provide a perspective on how manipulation of autophagy may potentially be used to treat mucosal inflammatory disorders. PMID:27446072

  20. Transcriptional regulation of mammalian autophagy at a glance.

    Science.gov (United States)

    Füllgrabe, Jens; Ghislat, Ghita; Cho, Dong-Hyung; Rubinsztein, David C

    2016-08-15

    Macroautophagy, hereafter referred to as autophagy, is a catabolic process that results in the lysosomal degradation of cytoplasmic contents ranging from abnormal proteins to damaged cell organelles. It is activated  under diverse conditions, including nutrient deprivation and hypoxia. During autophagy, members of the core autophagy-related (ATG) family of proteins mediate membrane rearrangements, which lead to the engulfment and degradation of cytoplasmic cargo. Recently, the nuclear regulation of autophagy, especially by transcription factors and histone modifiers, has gained increased attention. These factors are not only involved in rapid responses to autophagic stimuli, but also regulate the long-term outcome of autophagy. Now there are more than 20 transcription factors that have been shown to be linked to the autophagic process. However, their interplay and timing appear enigmatic as several have been individually shown to act as major regulators of autophagy. This Cell Science at a Glance article and the accompanying poster highlights the main cellular regulators of transcription involved in mammalian autophagy and their target genes. PMID:27528206

  1. The Regulation of Autophagy by Influenza A Virus

    Directory of Open Access Journals (Sweden)

    Rong Zhang

    2014-01-01

    Full Text Available Influenza A virus is a dreadful pathogen of animals and humans, causing widespread infection and severe morbidity and mortality. It is essential to characterize the influenza A virus-host interaction and develop efficient counter measures against the viral infection. Autophagy is known as a catabolic process for the recycling of the cytoplasmic macromolecules. Recently, it has been shown that autophagy is a critical mechanism underlying the interaction between influenza A virus and its host. Autophagy can be induced by the infection with influenza A virus, which is considered as a necessary process for the viral proliferation, including the accumulation of viral elements during the replication of influenza A virus. On the other hand, influenza A virus can inhibit the autophagic formation via interaction with the autophagy-related genes (Atg and signaling pathways. In addition, autophagy is involved in the influenza virus-regulated cell deaths, leading to significant changes in host apoptosis. Interestingly, the high pathogenic strains of influenza A virus, such as H5N1, stimulate autophagic cell death and appear to interplay with the autophagy in distinct ways as compared with low pathogenic strains. This review discusses the regulation of autophagy, an influenza A virus driven process.

  2. TOR-dependent post-transcriptional regulation of autophagy.

    Science.gov (United States)

    Hu, Guowu; McQuiston, Travis; Bernard, Amélie; Park, Yoon-Dong; Qiu, Jin; Vural, Ali; Zhang, Nannan; Waterman, Scott R; Blewett, Nathan H; Myers, Timothy G; Maraia, Richard J; Kehrl, John H; Uzel, Gulbu; Klionsky, Daniel J; Williamson, Peter R

    2015-01-01

    Regulation of autophagy is required to maintain cellular equilibrium and prevent disease. While extensive study of post-translational mechanisms has yielded important insights into autophagy induction, less is known about post-transcriptional mechanisms that could potentiate homeostatic control. In our study, we showed that the RNA-binding protein, Dhh1 in Saccharomyces cerevisiae and Vad1 in the pathogenic yeast Cryptococcus neoformans is involved in recruitment and degradation of key autophagy mRNAs. In addition, phosphorylation of the decapping protein Dcp2 by the target of rapamycin (TOR), facilitates decapping and degradation of autophagy-related mRNAs, resulting in repression of autophagy under nutrient-replete conditions. The post-transcriptional regulatory process is conserved in both mouse and human cells and plays a role in autophagy-related modulation of the inflammasome product IL1B. These results were then applied to provide mechanistic insight into autoimmunity of a patient with a PIK3CD/p110δ gain-of-function mutation. These results thus identify an important new post-transcriptional mechanism of autophagy regulation that is highly conserved between yeast and mammals.

  3. Autophagy Regulatory Network - a systems-level bioinformatics resource for studying the mechanism and regulation of autophagy.

    Science.gov (United States)

    Türei, Dénes; Földvári-Nagy, László; Fazekas, Dávid; Módos, Dezső; Kubisch, János; Kadlecsik, Tamás; Demeter, Amanda; Lenti, Katalin; Csermely, Péter; Vellai, Tibor; Korcsmáros, Tamás

    2015-01-01

    Autophagy is a complex cellular process having multiple roles, depending on tissue, physiological, or pathological conditions. Major post-translational regulators of autophagy are well known, however, they have not yet been collected comprehensively. The precise and context-dependent regulation of autophagy necessitates additional regulators, including transcriptional and post-transcriptional components that are listed in various datasets. Prompted by the lack of systems-level autophagy-related information, we manually collected the literature and integrated external resources to gain a high coverage autophagy database. We developed an online resource, Autophagy Regulatory Network (ARN; http://autophagy-regulation.org), to provide an integrated and systems-level database for autophagy research. ARN contains manually curated, imported, and predicted interactions of autophagy components (1,485 proteins with 4,013 interactions) in humans. We listed 413 transcription factors and 386 miRNAs that could regulate autophagy components or their protein regulators. We also connected the above-mentioned autophagy components and regulators with signaling pathways from the SignaLink 2 resource. The user-friendly website of ARN allows researchers without computational background to search, browse, and download the database. The database can be downloaded in SQL, CSV, BioPAX, SBML, PSI-MI, and in a Cytoscape CYS file formats. ARN has the potential to facilitate the experimental validation of novel autophagy components and regulators. In addition, ARN helps the investigation of transcription factors, miRNAs and signaling pathways implicated in the control of the autophagic pathway. The list of such known and predicted regulators could be important in pharmacological attempts against cancer and neurodegenerative diseases.

  4. Independent Stem Cell Lineages Regulate Adipose Organogenesis and Adipose Homeostasis

    Directory of Open Access Journals (Sweden)

    Yuwei Jiang

    2014-11-01

    Full Text Available Adipose tissues have striking plasticity, highlighted by childhood and adult obesity. Using adipose lineage analyses, smooth muscle actin (SMA-mural cell-fate mapping, and conditional PPARγ deletion to block adipocyte differentiation, we find two phases of adipocyte generation that emanate from two independent adipose progenitor compartments: developmental and adult. These two compartments are sequentially required for organ formation and maintenance. Although both developmental and adult progenitors are specified during the developmental period and express PPARγ, they have distinct microanatomical, functional, morphogenetic, and molecular profiles. Furthermore, the two compartments derive from different lineages; whereas adult adipose progenitors fate-map from an SMA+ mural lineage, developmental progenitors do not. Remarkably, the adult progenitor compartment appears to be specified earlier than the developmental cells and then enters the already developmentally formed adipose depots. Thus, two distinct cell compartments control adipose organ development and organ homeostasis, which may provide a discrete therapeutic target for childhood and adult obesity.

  5. FoxO1 antagonist suppresses autophagy and lipid droplet growth in adipocytes.

    Science.gov (United States)

    Liu, Longhua; Zheng, Louise D; Zou, Peng; Brooke, Joseph; Smith, Cayleen; Long, Yun Chau; Almeida, Fabio A; Liu, Dongmin; Cheng, Zhiyong

    2016-08-01

    Obesity and related metabolic disorders constitute one of the most pressing heath concerns worldwide. Increased adiposity is linked to autophagy upregulation in adipose tissues. However, it is unknown how autophagy is upregulated and contributes to aberrant adiposity. Here we show a FoxO1-autophagy-FSP27 axis that regulates adipogenesis and lipid droplet (LD) growth in adipocytes. Adipocyte differentiation was associated with upregulation of autophagy and fat specific protein 27 (FSP27), a key regulator of adipocyte maturation and expansion by promoting LD formation and growth. However, FoxO1 specific inhibitor AS1842856 potently suppressed autophagy, FSP27 expression, and adipocyte differentiation. In terminally differentiated adipocytes, AS1842856 significantly reduced FSP27 level and LD size, which was recapitulated by autophagy inhibitors (bafilomycin-A1 and leupeptin, BL). Similarly, AS1842856 and BL dampened autophagy activity and FSP27 expression in explant cultures of white adipose tissue. To our knowledge, this is the first study addressing FoxO1 in the regulation of adipose autophagy, shedding light on the mechanism of increased autophagy and adiposity in obese individuals. Given that adipogenesis and adipocyte expansion contribute to aberrant adiposity, targeting the FoxO1-autophagy-FSP27 axis may lead to new anti-obesity options. PMID:27260854

  6. Transcriptional and epigenetic regulation of autophagy in aging.

    Science.gov (United States)

    Lapierre, Louis R; Kumsta, Caroline; Sandri, Marco; Ballabio, Andrea; Hansen, Malene

    2015-01-01

    Macroautophagy is a major intracellular degradation process recognized as playing a central role in cell survival and longevity. This multistep process is extensively regulated at several levels, including post-translationally through the action of conserved longevity factors such as the nutrient sensor TOR. More recently, transcriptional regulation of autophagy genes has emerged as an important mechanism for ensuring the somatic maintenance and homeostasis necessary for a long life span. Autophagy is increased in many long-lived model organisms and contributes significantly to their longevity. In turn, conserved transcription factors, particularly the helix-loop-helix transcription factor TFEB and the forkhead transcription factor FOXO, control the expression of many autophagy-related genes and are important for life-span extension. In this review, we discuss recent progress in understanding the contribution of these transcription factors to macroautophagy regulation in the context of aging. We also review current research on epigenetic changes, such as histone modification by the deacetylase SIRT1, that influence autophagy-related gene expression and additionally affect aging. Understanding the molecular regulation of macroautophagy in relation to aging may offer new avenues for the treatment of age-related diseases.

  7. SIRT5 regulation of ammonia-induced autophagy and mitophagy.

    Science.gov (United States)

    Polletta, Lucia; Vernucci, Enza; Carnevale, Ilaria; Arcangeli, Tania; Rotili, Dante; Palmerio, Silvia; Steegborn, Clemens; Nowak, Theresa; Schutkowski, Mike; Pellegrini, Laura; Sansone, Luigi; Villanova, Lidia; Runci, Alessandra; Pucci, Bruna; Morgante, Emanuela; Fini, Massimo; Mai, Antonello; Russo, Matteo A; Tafani, Marco

    2015-01-01

    In liver the mitochondrial sirtuin, SIRT5, controls ammonia detoxification by regulating CPS1, the first enzyme of the urea cycle. However, while SIRT5 is ubiquitously expressed, urea cycle and CPS1 are only present in the liver and, to a minor extent, in the kidney. To address the possibility that SIRT5 is involved in ammonia production also in nonliver cells, clones of human breast cancer cell lines MDA-MB-231 and mouse myoblast C2C12, overexpressing or silenced for SIRT5 were produced. Our results show that ammonia production increased in SIRT5-silenced and decreased in SIRT5-overexpressing cells. We also obtained the same ammonia increase when using a new specific inhibitor of SIRT5 called MC3482. SIRT5 regulates ammonia production by controlling glutamine metabolism. In fact, in the mitochondria, glutamine is transformed in glutamate by the enzyme glutaminase, a reaction producing ammonia. We found that SIRT5 and glutaminase coimmunoprecipitated and that SIRT5 inhibition resulted in an increased succinylation of glutaminase. We next determined that autophagy and mitophagy were increased by ammonia by measuring autophagic proteolysis of long-lived proteins, increase of autophagy markers MAP1LC3B, GABARAP, and GABARAPL2, mitophagy markers BNIP3 and the PINK1-PARK2 system as well as mitochondrial morphology and dynamics. We observed that autophagy and mitophagy increased in SIRT5-silenced cells and in WT cells treated with MC3482 and decreased in SIRT5-overexpressing cells. Moreover, glutaminase inhibition or glutamine withdrawal completely prevented autophagy. In conclusion we propose that the role of SIRT5 in nonliver cells is to regulate ammonia production and ammonia-induced autophagy by regulating glutamine metabolism.

  8. mir-30d Regulates multiple genes in the autophagy pathway and impairs autophagy process in human cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaojun [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Department of General Surgery, Gansu Provincial Hospital, Lanzhou, Gansu 710000 (China); Zhong, Xiaomin [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011 (China); Tanyi, Janos L.; Shen, Jianfeng [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Xu, Congjian [Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011 (China); Gao, Peng [Department of General Surgery, Gansu Provincial Hospital, Lanzhou, Gansu 710000 (China); Zheng, Tim M. [Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104 (United States); DeMichele, Angela [Division of Hematology and Oncology, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104 (United States); Zhang, Lin, E-mail: linzhang@mail.med.upenn.edu [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States)

    2013-02-15

    Highlights: ► Gene set enrichment analysis indicated mir-30d might regulate the autophagy pathway. ► mir-30d represses the expression of BECN1, BNIP3L, ATG12, ATG5 and ATG2. ► BECN1, BNIP3L, ATG12, ATG5 and ATG2 are direct targets of mir-30d. ► mir-30d inhibits autophagosome formation and LC3B-I conversion to LC3B-II. ► mir-30d regulates the autophagy process. -- Abstract: In human epithelial cancers, the microRNA (miRNA) mir-30d is amplified with high frequency and serves as a critical oncomir by regulating metastasis, apoptosis, proliferation, and differentiation. Autophagy, a degradation pathway for long-lived protein and organelles, regulates the survival and death of many cell types. Increasing evidence suggests that autophagy plays an important function in epithelial tumor initiation and progression. Using a combined bioinformatics approach, gene set enrichment analysis, and miRNA target prediction, we found that mir-30d might regulate multiple genes in the autophagy pathway including BECN1, BNIP3L, ATG12, ATG5, and ATG2. Our further functional experiments demonstrated that the expression of these core proteins in the autophagy pathway was directly suppressed by mir-30d in cancer cells. Finally, we showed that mir-30d regulated the autophagy process by inhibiting autophagosome formation and LC3B-I conversion to LC3B-II. Taken together, our results provide evidence that the oncomir mir-30d impairs the autophagy process by targeting multiple genes in the autophagy pathway. This result will contribute to understanding the molecular mechanism of mir-30d in tumorigenesis and developing novel cancer therapy strategy.

  9. The late stage of autophagy: cellular events and molecular regulation

    OpenAIRE

    Tong, Jingjing; Yan, Xianghua; Yu, Li

    2010-01-01

    Autophagy is an intracellular degradation system that delivers cytoplasmic contents to the lysosome for degradation. It is a “self-eating” process and plays a “house-cleaner” role in cells. The complex process consists of several sequential steps—induction, autophagosome formation, fusion of lysosome and autophagosome, degradation, efflux transportation of degradation products, and autophagic lysosome reformation. In this review, the cellular and molecular regulations of late stage of autopha...

  10. VMP1 related autophagy and apoptosis in colorectal cancer cells: VMP1 regulates cell death

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Qinyi [Department of Ultrasonograph, Changshu No. 2 People’s Hospital, Changshu (China); Zhou, Hao; Chen, Yan [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou (China); Shen, Chenglong [Department of General Surgery, Changshu No. 2 People’s Hospital, Changshu (China); He, Songbing; Zhao, Hua; Wang, Liang [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou (China); Wan, Daiwei, E-mail: 372710369@qq.com [Department of Hepatobiliary Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou (China); Gu, Wen, E-mail: 505339704@qq.com [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou (China)

    2014-01-17

    Highlights: •This research confirmed VMP1 as a regulator of autophagy in colorectal cancer cell lines. •We proved the pro-survival role of VMP1-mediated autophagy in colorectal cancer cell lines. •We found the interaction between VMP1 and BECLIN1 also existing in colorectal cancer cell lines. -- Abstract: Vacuole membrane protein 1 (VMP1) is an autophagy-related protein and identified as a key regulator of autophagy in recent years. In pancreatic cell lines, VMP1-dependent autophagy has been linked to positive regulation of apoptosis. However, there are no published reports on the role of VMP1 in autophagy and apoptosis in colorectal cancers. Therefore, to address this gap of knowledge, we decided to interrogate regulation of autophagy and apoptosis by VMP1. We have studied the induction of autophagy by starvation and rapamycin treatment in colorectal cell lines using electron microscopy, immunofluorescence, and immunoblotting. We found that starvation-induced autophagy correlated with an increase in VMP1 expression, that VMP1 interacted with BECLIN1, and that siRNA mediated down-regulation of VMP1-reduced autophagy. Next, we examined the relationship between VMP1-dependent autophagy and apoptosis and found that VMP1 down-regulation sensitizes cells to apoptosis and that agents that induce apoptosis down-regulate VMP1. In conclusion, similar to its reported role in other cell types, VMP1 is an important regulator of autophagy in colorectal cell lines. However, in contrast to its role in pancreatic cell lines, in colorectal cancer cells, VMP1-dependent autophagy appears to be pro-survival rather than pro-cell death.

  11. The Importance of Autophagy Regulation in Breast Cancer Development and Treatment

    Directory of Open Access Journals (Sweden)

    Joanna Magdalena Zarzynska

    2014-01-01

    Full Text Available Breast cancer (BC is a potentially life-threatening malignant tumor that still causes high mortality among women. One of the mechanisms through which cancer development could be controlled is autophagy. This process exerts different effects during the stages of cancer initiation and progression due to the occurring superimposition of signaling pathways of autophagy and carcinogenesis. Chronic inhibition of autophagy or autophagy deficiency promotes cancer, due to instability of the genome and defective cell growth and as a result of cell stress. However, increased induction of autophagy can become a mechanism which allows tumor cells to survive the conditions of hypoxia, acidosis, or chemotherapy. Therefore, in the development of cancer, autophagy is regarded as a double-edged sword. Determination of the molecular mechanisms underlying autophagy regulation and its role in tumorigenesis is an essential component of modern anticancer strategies. Results of scientific studies show that inhibition of autophagy may enhance the effectiveness of currently used anticancer drugs and other therapies (like radiotherapy. However, in some cases, the promotion of autophagy can induce death and, hence, elimination of the cancer cells and reduction of tumor size. This review summarizes the current knowledge on autophagy regulation in BC and up-to-date anticancer strategies correlated with autophagy.

  12. Regulation of autophagy in human skeletal muscle: effects of exercise, exercise training and insulin stimulation

    DEFF Research Database (Denmark)

    Fritzen, Andreas Mæchel; Madsen, Agnete Louise Bjerregaard; Kleinert, Maximilian;

    2016-01-01

    Studies in rodent muscle suggest that autophagy is regulated by acute exercise, exercise training and insulin stimulation. However, little is known about the regulation of autophagy in human skeletal muscle. Here we investigate the autophagic response to acute one-legged exercise, one...... increase the capacity for formation of autophagosomes in muscle. Moreover, AMPK activation during exercise may not be sufficient to regulate autophagy in muscle, while mTORC1 signalling via ULK1 likely mediates the autophagy-inhibiting effect of insulin. This article is protected by copyright. All rights...

  13. Exercise induces autophagy in peripheral tissues and in the brain

    OpenAIRE

    He, Congcong; Sumpter, Jr., Rhea; Levine, Beth

    2012-01-01

    We recently identified physical exercise as a newly defined inducer of autophagy in vivo. Exercise induced autophagy in multiple organs involved in metabolic regulation, such as muscle, liver, pancreas and adipose tissue. To study the physiological role of exercise-induced autophagy, we generated mice with a knock-in nonphosphorylatable mutation in BCL2 (Thr69Ala, Ser70Ala and Ser84Ala) (BCL2 AAA) that are defective in exercise- and starvation-induced autophagy but not in basal autophagy. We ...

  14. Regulation of Autophagy of Prostate Cancer Cells by β-Catenin Signaling

    Directory of Open Access Journals (Sweden)

    Rongkai Lin

    2015-01-01

    Full Text Available Background/Aims: Autophagy is a cellular degradation process for the recycling of damaged or superfluous intracellular compartments to provide an alternative energy source during periods of metabolic stress for maintaining cell homeostasis and viability. Although autophagy in different contexts have been shown to use similar signaling pathways, the exact molecular regulation of autophagy has been found to be cell-type dependent. Methods: We used rapamycin to trigger autophagy and used nitric oxide (NO to inhibit autophagy in prostate cancer cells. IWP-2 was used to inhibit β-catenin signaling. Autophagy-associated proteins were examined by Western blot. Results: We found that nitric oxide (NO, a potent cellular messenger, impaired rapamycin-induced autophagy in prostate cancer cells. Further analyses showed that NO induced nuclear accumulation of β-catenin, a key factor of Wnt signaling pathway, to inhibit autophagy in prostate cancer cells. Conclusions: We demonstrate involvement of β-catenin signaling in the regulation of autophagy of prostate cancer cells. Our results shed light on a previously unappreciated β-catenin signaling pathway for regulating autophagy in prostate cancer.

  15. Regulation of systemic energy homeostasis by serotonin in adipose tissues.

    Science.gov (United States)

    Oh, Chang-Myung; Namkung, Jun; Go, Younghoon; Shong, Ko Eun; Kim, Kyuho; Kim, Hyeongseok; Park, Bo-Yoon; Lee, Ho Won; Jeon, Yong Hyun; Song, Junghan; Shong, Minho; Yadav, Vijay K; Karsenty, Gerard; Kajimura, Shingo; Lee, In-Kyu; Park, Sangkyu; Kim, Hail

    2015-04-13

    Central serotonin (5-HT) is an anorexigenic neurotransmitter in the brain. However, accumulating evidence suggests peripheral 5-HT may affect organismal energy homeostasis. Here we show 5-HT regulates white and brown adipose tissue function. Pharmacological inhibition of 5-HT synthesis leads to inhibition of lipogenesis in epididymal white adipose tissue (WAT), induction of browning in inguinal WAT and activation of adaptive thermogenesis in brown adipose tissue (BAT). Mice with inducible Tph1 KO in adipose tissues exhibit a similar phenotype as mice in which 5-HT synthesis is inhibited pharmacologically, suggesting 5-HT has localized effects on adipose tissues. In addition, Htr3a KO mice exhibit increased energy expenditure and reduced weight gain when fed a high-fat diet. Treatment with an Htr2a antagonist reduces lipid accumulation in 3T3-L1 adipocytes. These data suggest important roles for adipocyte-derived 5-HT in controlling energy homeostasis.

  16. Hepatic oleate regulates adipose tissue lipogenesis and fatty acid oxidation.

    Science.gov (United States)

    Burhans, Maggie S; Flowers, Matthew T; Harrington, Kristin R; Bond, Laura M; Guo, Chang-An; Anderson, Rozalyn M; Ntambi, James M

    2015-02-01

    Hepatic steatosis is associated with detrimental metabolic phenotypes including enhanced risk for diabetes. Stearoyl-CoA desaturases (SCDs) catalyze the synthesis of MUFAs. In mice, genetic ablation of SCDs reduces hepatic de novo lipogenesis (DNL) and protects against diet-induced hepatic steatosis and adiposity. To understand the mechanism by which hepatic MUFA production influences adipose tissue stores, we created two liver-specific transgenic mouse models in the SCD1 knockout that express either human SCD5 or mouse SCD3, that synthesize oleate and palmitoleate, respectively. We demonstrate that hepatic de novo synthesized oleate, but not palmitoleate, stimulate hepatic lipid accumulation and adiposity, reversing the protective effect of the global SCD1 knockout under lipogenic conditions. Unexpectedly, the accumulation of hepatic lipid occurred without induction of the hepatic DNL program. Changes in hepatic lipid composition were reflected in plasma and in adipose tissue. Importantly, endogenously synthesized hepatic oleate was associated with suppressed DNL and fatty acid oxidation in white adipose tissue. Regression analysis revealed a strong correlation between adipose tissue lipid fuel utilization and hepatic and adipose tissue lipid storage. These data suggest an extrahepatic mechanism where endogenous hepatic oleate regulates lipid homeostasis in adipose tissues.

  17. Naringin-sensitive protein phosphorylation pathways in the regulation of hepatocytic autophagy

    OpenAIRE

    2004-01-01

    Autophagy is a process used by eukaryotic cells to degrade their own cytoplasm under conditions of nitrogen starvation or stress, in order to obtain amino acids and other small molecules needed for the maintenance of essential cell functions. A variety of biological agents have been described to take part in the regulation of mammalian autophagy. Naringin, a flavanone isolated from grapefruit peel as the bitter principle, is known to exhibit autophagy-preserving effects in isolated hepatoc...

  18. Adipose Natural Killer Cells Regulate Adipose Tissue Macrophages to Promote Insulin Resistance in Obesity.

    Science.gov (United States)

    Lee, Byung-Cheol; Kim, Myung-Sunny; Pae, Munkyong; Yamamoto, Yasuhiko; Eberlé, Delphine; Shimada, Takeshi; Kamei, Nozomu; Park, Hee-Sook; Sasorith, Souphatta; Woo, Ju Rang; You, Jia; Mosher, William; Brady, Hugh J M; Shoelson, Steven E; Lee, Jongsoon

    2016-04-12

    Obesity-induced inflammation mediated by immune cells in adipose tissue appears to participate in the pathogenesis of insulin resistance. We show that natural killer (NK) cells in adipose tissue play an important role. High-fat diet (HFD) increases NK cell numbers and the production of proinflammatory cytokines, notably TNFα, in epididymal, but not subcutaneous, fat depots. When NK cells were depleted either with neutralizing antibodies or genetic ablation in E4bp4(+/-) mice, obesity-induced insulin resistance improved in parallel with decreases in both adipose tissue macrophage (ATM) numbers, and ATM and adipose tissue inflammation. Conversely, expansion of NK cells following IL-15 administration or reconstitution of NK cells into E4bp4(-/-) mice increased both ATM numbers and adipose tissue inflammation and exacerbated HFD-induced insulin resistance. These results indicate that adipose NK cells control ATMs as an upstream regulator potentially by producing proinflammatory mediators, including TNFα, and thereby contribute to the development of obesity-induced insulin resistance.

  19. Exercise Regulation of Marrow Adipose Tissue

    Directory of Open Access Journals (Sweden)

    Gabriel M Pagnotti

    2016-07-01

    Full Text Available Despite association with low bone density and skeletal fractures, marrow adipose tissue (MAT remains poorly understood. The marrow adipocyte originates from the mesenchymal stem cell pool (MSC that gives rise also to osteoblasts, chondrocytes, and myocytes among other cell types. To date, the presence of MAT has been attributed to preferential biasing of MSC into the adipocyte rather than osteoblast lineage, thus negatively impacting bone formation. Here we focus on understanding the physiology of MAT in the setting of exercise, dietary interventions and pharmacologic agents that alter fat metabolism. The beneficial effect of exercise on musculoskeletal strength is known: exercise induces bone formation, encourages growth of skeletally-supportive tissues, inhibits bone resorption and alters skeletal architecture through direct and indirect effects on a multiplicity of cells involved in skeletal adaptation. MAT is less well studied due to the lack of reproducible quantification techniques. In recent work, osmium-based 3D quantification shows a robust response of MAT to both dietary and exercise intervention in that MAT is elevated in response to high fat diet and can be suppressed following daily exercise. Exercise-induced bone formation correlates with suppression of MAT, such that exercise effects might be due to either calorie expenditure from this depot, or from mechanical biasing of MSC lineage away from fat and toward bone, or a combination thereof. Following treatment with the anti-diabetes drug rosiglitazone - a PPARγ-agonist known to increase MAT and fracture risk - mice demonstrate a 5-fold higher femur MAT volume compared to the controls. In addition to preventing MAT accumulation in control mice, exercise intervention significantly lowers MAT accumulation in rosiglitazone-treated mice. Importantly, exercise induction of trabecular bone volume is unhindered by rosiglitazone. Thus, despite rosiglitazone augmentation of MAT, exercise

  20. Reciprocal regulation of cilia and autophagy via the MTOR and proteasome pathways.

    Science.gov (United States)

    Wang, Shixuan; Livingston, Man J; Su, Yunchao; Dong, Zheng

    2015-04-01

    Primary cilium is an organelle that plays significant roles in a number of cellular functions ranging from cell mechanosensation, proliferation, and differentiation to apoptosis. Autophagy is an evolutionarily conserved cellular function in biology and indispensable for cellular homeostasis. Both cilia and autophagy have been linked to different types of genetic and acquired human diseases. Their interaction has been suggested very recently, but the underlying mechanisms are still not fully understood. We examined autophagy in cells with suppressed cilia and measured cilium length in autophagy-activated or -suppressed cells. It was found that autophagy was repressed in cells with short cilia. Further investigation showed that MTOR activation was enhanced in cilia-suppressed cells and the MTOR inhibitor rapamycin could largely reverse autophagy suppression. In human kidney proximal tubular cells (HK2), autophagy induction was associated with cilium elongation. Conversely, autophagy inhibition by 3-methyladenine (3-MA) and chloroquine (CQ) as well as bafilomycin A1 (Baf) led to short cilia. Cilia were also shorter in cultured atg5-knockout (KO) cells and in atg7-KO kidney proximal tubular cells in mice. MG132, an inhibitor of the proteasome, could significantly restore cilium length in atg5-KO cells, being concomitant with the proteasome activity. Together, the results suggest that cilia and autophagy regulate reciprocally through the MTOR signaling pathway and ubiquitin-proteasome system.

  1. There is more to autophagy than induction: regulating the roller coaster.

    Science.gov (United States)

    Klionsky, Daniel J; Nemchenko, Andriy

    2011-08-01

    Considerable attention has been paid to the topic of autophagy induction. In part, this is because of the potential for modulating this process for therapeutic purposes. Of course we know that induced autophagy can also be problematic--for example, when trying to eliminate an established tumor that might be relying on autophagy for its own cytoprotective uses. Accordingly, inhibitory mechanisms have been considered; however, the corresponding studies have tended to focus on the pathways that block autophagy under non-inducing conditions, such as when nutrients are available. In contrast, relatively little is known about the mechanisms for inhibiting autophagy under inducing conditions. Yet, this type of regulation must be occurring on a routine basis. We know that dysregulation of autophagy, e.g., due to improper activation of Beclin 1 leading to excessive autophagy activity, can cause cell death. Accordingly, we assume that during starvation or other inducing conditions there must be a mechanism to modulate autophagy. That is, once you turn it on, you do not want to let it continue unchecked. But how is autophagy downregulated when the inducing conditions still exist? PMID:21636971

  2. Stress-induced self-cannibalism: on the regulation of autophagy by endoplasmic reticulum stress.

    Science.gov (United States)

    Deegan, Shane; Saveljeva, Svetlana; Gorman, Adrienne M; Samali, Afshin

    2013-07-01

    Macroautophagy (autophagy) is a cellular catabolic process which can be described as a self-cannibalism. It serves as an essential protective response during conditions of endoplasmic reticulum (ER) stress through the bulk removal and degradation of unfolded proteins and damaged organelles; in particular, mitochondria (mitophagy) and ER (reticulophagy). Autophagy is genetically regulated and the autophagic machinery facilitates removal of damaged cell components and proteins; however, if the cell stress is acute or irreversible, cell death ensues. Despite these advances in the field, very little is known about how autophagy is initiated and how the autophagy machinery is transcriptionally regulated in response to ER stress. Some three dozen autophagy genes have been shown to be required for the correct assembly and function of the autophagic machinery; however; very little is known about how these genes are regulated by cellular stress. Here, we will review current knowledge regarding how ER stress and the unfolded protein response (UPR) induce autophagy, including description of the different autophagy-related genes which are regulated by the UPR. PMID:23052213

  3. TORC1 Inhibits GSK3-Mediated Elo2 Phosphorylation to Regulate Very Long Chain Fatty Acid Synthesis and Autophagy

    DEFF Research Database (Denmark)

    Zimmermann, Christine; Santos, Aline; Gable, Kenneth;

    2013-01-01

    the ceramide spectrum, reflecting aberrant VLCFA synthesis. Furthermore, VLCFA depletion results in constitutive activation of autophagy, which requires sphingoid base phosphorylation. This constitutive activation of autophagy diminishes cell survival, indicating that VLCFAs serve to dampen the amplitude...... of autophagy. Together, our data reveal a function for TORC1 and GSK3 in the regulation of VLCFA synthesis that has important implications for autophagy and cell homeostasis....

  4. Autophagy regulates keratin 8 homeostasis in mammary epithelial cells and in breast tumors

    Science.gov (United States)

    Kongara, Sameera; Kravchuk, Olga; Teplova, Irina; Lozy, Fred; Schulte, Jennifer; Moore, Dirk; Barnard, Nicola; Neumann, Carola A.; White, Eileen; Karantza, Vassiliki

    2010-01-01

    Autophagy is activated in response to cellular stressors and mediates lysosomal degradation and recycling of cytoplasmic material and organelles as a temporary cell survival mechanism. Defective autophagy is implicated in human pathology, as disruption of protein and organelle homeostasis enables disease-promoting mechanisms such as toxic protein aggregation, oxidative stress, genomic damage and inflammation. We previously showed that autophagy-defective immortalized mouse mammary epithelial cells (iMMECs) are susceptible to metabolic stress, DNA damage and genomic instability. We now report that autophagy deficiency was associated with ER and oxidative stress, and deregulation of p62-mediated keratin homeostasis in mammary cells and allograft tumors and in mammary tissues from genetically engineered mice. In human breast tumors, high phospho(Ser73)-K8 levels inversely correlated with Beclin 1 expression. Thus, autophagy preserves cellular fitness by limiting ER and oxidative stress, a function potentially important in autophagy-mediated suppression of mammary tumorigenesis. Furthermore, autophagy regulates keratin homeostasis in the mammary gland via a p62-dependent mechanism. High phospho(Ser73)-K8 expression may be a marker of autophagy functional status in breast tumors and, as such, could have therapeutic implications for breast cancer patients. PMID:20530580

  5. Reciprocal regulation of autophagy and dNTP pools in human cancer cells.

    Science.gov (United States)

    Chen, Wei; Zhang, Lisheng; Zhang, Keqiang; Zhou, Bingsen; Kuo, Mei-Ling; Hu, Shuya; Chen, Linling; Tang, Michelle; Chen, Yun-Ru; Yang, Lixin; Ann, David K; Yen, Yun

    2014-07-01

    Ribonucleotide reductase (RNR) plays a critical role in catalyzing the biosynthesis and maintaining the intracellular concentration of 4 deoxyribonucleoside triphosphates (dNTPs). Unbalanced or deficient dNTP pools cause serious genotoxic consequences. Autophagy is the process by which cytoplasmic constituents are degraded in lysosomes to maintain cellular homeostasis and bioenergetics. However, the role of autophagy in regulating dNTP pools is not well understood. Herein, we reported that starvation- or rapamycin-induced autophagy was accompanied by a decrease in RNR activity and dNTP pools in human cancer cells. Furthermore, downregulation of the small subunit of RNR (RRM2) by siRNA or treatment with the RNR inhibitor hydroxyurea substantially induced autophagy. Conversely, cancer cells with abundant endogenous intracellular dNTPs or treated with dNTP precursors were less responsive to autophagy induction by rapamycin, suggesting that autophagy and dNTP pool levels are regulated through a negative feedback loop. Lastly, treatment with si-RRM2 caused an increase in MAP1LC3B, ATG5, BECN1, and ATG12 transcript abundance in xenografted Tu212 tumors in vivo. Together, our results revealed a previously unrecognized reciprocal regulation between dNTP pools and autophagy in cancer cells.

  6. Transcription factors and cognate signalling cascades in the regulation of autophagy.

    Science.gov (United States)

    Chandra, Vemika; Bhagyaraj, Ella; Parkesh, Raman; Gupta, Pawan

    2016-05-01

    Autophagy is a process that maintains the equilibrium between biosynthesis and the recycling of cellular constituents; it is critical for avoiding the pathophysiology that results from imbalance in cellular homeostasis. Recent reports indicate the need for the design of high-throughput screening assays to identify targets and small molecules for autophagy modulation. For such screening, however, a better understanding of the regulation of autophagy is essential. In addition to regulation by various signalling cascades, regulation of gene expression by transcription factors is also critical. This review focuses on the various transcription factors as well as the corresponding signalling molecules that act together to translate the stimuli to effector molecules that up- or downregulate autophagy. This review rationalizes the importance of these transcription factors functioning in tandem with cognate signalling molecules and their interfaces as possible therapeutic targets for more specific pharmacological interventions. PMID:25651938

  7. IL13 activates autophagy to regulate secretion in airway epithelial cells.

    Science.gov (United States)

    Dickinson, John D; Alevy, Yael; Malvin, Nicole P; Patel, Khushbu K; Gunsten, Sean P; Holtzman, Michael J; Stappenbeck, Thaddeus S; Brody, Steven L

    2016-01-01

    Cytokine modulation of autophagy is increasingly recognized in disease pathogenesis, and current concepts suggest that type 1 cytokines activate autophagy, whereas type 2 cytokines are inhibitory. However, this paradigm derives primarily from studies of immune cells and is poorly characterized in tissue cells, including sentinel epithelial cells that regulate the immune response. In particular, the type 2 cytokine IL13 (interleukin 13) drives the formation of airway goblet cells that secrete excess mucus as a characteristic feature of airway disease, but whether this process is influenced by autophagy was undefined. Here we use a mouse model of airway disease in which IL33 (interleukin 33) stimulation leads to IL13-dependent formation of airway goblet cells as tracked by levels of mucin MUC5AC (mucin 5AC, oligomeric mucus/gel forming), and we show that these cells manifest a block in mucus secretion in autophagy gene Atg16l1-deficient mice compared to wild-type control mice. Similarly, primary-culture human tracheal epithelial cells treated with IL13 to stimulate mucus formation also exhibit a block in MUC5AC secretion in cells depleted of autophagy gene ATG5 (autophagy-related 5) or ATG14 (autophagy-related 14) compared to nondepleted control cells. Our findings indicate that autophagy is essential for airway mucus secretion in a type 2, IL13-dependent immune disease process and thereby provide a novel therapeutic strategy for attenuating airway obstruction in hypersecretory inflammatory diseases such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis lung disease. Taken together, these observations suggest that the regulation of autophagy by Th2 cytokines is cell-context dependent.

  8. Regulation of autophagy and chloroquine sensitivity by oncogenic RAS in vitro is context-dependent.

    Science.gov (United States)

    Morgan, Michael J; Gamez, Graciela; Menke, Christina; Hernandez, Ariel; Thorburn, Jacqueline; Gidan, Freddi; Staskiewicz, Leah; Morgan, Shellie; Cummings, Christopher; Maycotte, Paola; Thorburn, Andrew

    2014-10-01

    Chloroquine (CQ) is an antimalarial drug and late-stage inhibitor of autophagy currently FDA-approved for use in the treatment of rheumatoid arthritis and other autoimmune diseases. Based primarily on its ability to inhibit autophagy, CQ and its derivative, hydroxychloroquine, are currently being investigated as primary or adjuvant therapy in multiple clinical trials for cancer treatment. Oncogenic RAS has previously been shown to regulate autophagic flux, and cancers with high incidence of RAS mutations, such as pancreatic cancer, have been described in the literature as being particularly susceptible to CQ treatment, leading to the hypothesis that oncogenic RAS makes cancer cells dependent on autophagy. This autophagy "addiction" suggests that the mutation status of RAS in tumors could identify patients who would be more likely to benefit from CQ therapy. Here we show that RAS mutation status itself is unlikely to be beneficial in such a patient selection because oncogenic RAS does not always promote autophagy addiction. Moreover, oncogenic RAS can have opposite effects on both autophagic flux and CQ sensitivity in different cells. Finally, for any given cell type, the positive or negative effect of oncogenic RAS on autophagy does not necessarily predict whether RAS will promote or inhibit CQ-mediated toxicity. Thus, although our results confirm that different tumor cell lines display marked differences in how they respond to autophagy inhibition, these differences can occur irrespective of RAS mutation status and, in different contexts, can either promote or reduce chloroquine sensitivity of tumor cells.

  9. Autophagy contributes to regulation of the hypoxia response during submergence in Arabidopsis thaliana.

    Science.gov (United States)

    Chen, Liang; Liao, Bin; Qi, Hua; Xie, Li-Juan; Huang, Li; Tan, Wei-Juan; Zhai, Ning; Yuan, Li-Bing; Zhou, Ying; Yu, Lu-Jun; Chen, Qin-Fang; Shu, Wensheng; Xiao, Shi

    2015-01-01

    Autophagy involves massive degradation of intracellular components and functions as a conserved system that helps cells to adapt to adverse conditions. In mammals, hypoxia rapidly stimulates autophagy as a cell survival response. Here, we examine the function of autophagy in the regulation of the plant response to submergence, an abiotic stress that leads to hypoxia and anaerobic respiration in plant cells. In Arabidopsis thaliana, submergence induces the transcription of autophagy-related (ATG) genes and the formation of autophagosomes. Consistent with this, the autophagy-defective (atg) mutants are hypersensitive to submergence stress and treatment with ethanol, the end product of anaerobic respiration. Upon submergence, the atg mutants have increased levels of transcripts of anaerobic respiration genes (alcohol dehydrogenase 1, ADH1 and pyruvate decarboxylase 1, PDC1), but reduced levels of transcripts of other hypoxia- and ethylene-responsive genes. Both submergence and ethanol treatments induce the accumulation of reactive oxygen species (ROS) in the rosettes of atg mutants more than in the wild type. Moreover, the production of ROS by the nicotinamide adenine dinucleotide phosphate (NADPH) oxidases is necessary for plant tolerance to submergence and ethanol, submergence-induced expression of ADH1 and PDC1, and activation of autophagy. The submergence- and ethanol-sensitive phenotypes in the atg mutants depend on a complete salicylic acid (SA) signaling pathway. Together, our findings demonstrate that submergence-induced autophagy functions in the hypoxia response in Arabidopsis by modulating SA-mediated cellular homeostasis.

  10. Notch1 regulated autophagy controls survival and suppressor activity of activated murine T-regulatory cells

    Science.gov (United States)

    Marcel, Nimi; Sarin, Apurva

    2016-01-01

    Cell survival is one of several processes regulated by the Notch pathway in mammalian cells. Here we report functional outcomes of non-nuclear Notch signaling to activate autophagy, a conserved cellular response to nutrient stress, regulating survival in murine natural T-regulatory cells (Tregs), an immune subset controlling tolerance and inflammation. Induction of autophagy required ligand-dependent, Notch intracellular domain (NIC) activity, which controlled mitochondrial organization and survival of activated Tregs. Consistently, NIC immune-precipitated Beclin and Atg14, constituents of the autophagy initiation complex. Further, ectopic expression of an effector of autophagy (Atg3) or recombinant NIC tagged to a nuclear export signal (NIC-NES), restored autophagy and suppressor function in Notch1-/- Tregs. Furthermore, Notch1 deficiency in the Treg lineage resulted in immune hyperactivity, implicating Notch activity in Treg homeostasis. Notch1 integration with autophagy, revealed in these experiments, holds implications for Notch regulated cell-fate decisions governing differentiation. DOI: http://dx.doi.org/10.7554/eLife.14023.001 PMID:27267497

  11. EVA1A/TMEM166 Regulates Embryonic Neurogenesis by Autophagy.

    Science.gov (United States)

    Li, Mengtao; Lu, Guang; Hu, Jia; Shen, Xue; Ju, Jiabao; Gao, Yuanxu; Qu, Liujing; Xia, Yan; Chen, Yingyu; Bai, Yun

    2016-03-01

    Self-renewal and differentiation of neural stem cells is essential for embryonic neurogenesis, which is associated with cell autophagy. However, the mechanism by which autophagy regulates neurogenesis remains undefined. Here, we show that Eva1a/Tmem166, an autophagy-related gene, regulates neural stem cell self-renewal and differentiation. Eva1a depletion impaired the generation of newborn neurons, both in vivo and in vitro. Conversely, overexpression of EVA1A enhanced newborn neuron generation and maturation. Moreover, Eva1a depletion activated the PIK3CA-AKT axis, leading to the activation of the mammalian target of rapamycin and the subsequent inhibition of autophagy. Furthermore, addition of methylpyruvate to the culture during neural stem cell differentiation rescued the defective embryonic neurogenesis induced by Eva1a depletion, suggesting that energy availability is a significant factor in embryonic neurogenesis. Collectively, these data demonstrated that EVA1A regulates embryonic neurogenesis by modulating autophagy. Our results have potential implications for understanding the pathogenesis of neurodevelopmental disorders caused by autophagy dysregulation. PMID:26905199

  12. EVA1A/TMEM166 Regulates Embryonic Neurogenesis by Autophagy

    Directory of Open Access Journals (Sweden)

    Mengtao Li

    2016-03-01

    Full Text Available Self-renewal and differentiation of neural stem cells is essential for embryonic neurogenesis, which is associated with cell autophagy. However, the mechanism by which autophagy regulates neurogenesis remains undefined. Here, we show that Eva1a/Tmem166, an autophagy-related gene, regulates neural stem cell self-renewal and differentiation. Eva1a depletion impaired the generation of newborn neurons, both in vivo and in vitro. Conversely, overexpression of EVA1A enhanced newborn neuron generation and maturation. Moreover, Eva1a depletion activated the PIK3CA-AKT axis, leading to the activation of the mammalian target of rapamycin and the subsequent inhibition of autophagy. Furthermore, addition of methylpyruvate to the culture during neural stem cell differentiation rescued the defective embryonic neurogenesis induced by Eva1a depletion, suggesting that energy availability is a significant factor in embryonic neurogenesis. Collectively, these data demonstrated that EVA1A regulates embryonic neurogenesis by modulating autophagy. Our results have potential implications for understanding the pathogenesis of neurodevelopmental disorders caused by autophagy dysregulation.

  13. FLCN, a novel autophagy component, interacts with GABARAP and is regulated by ULK1 phosphorylation.

    Science.gov (United States)

    Dunlop, Elaine A; Seifan, Sara; Claessens, Tijs; Behrends, Christian; Kamps, Miriam Af; Rozycka, Ewelina; Kemp, Alain J; Nookala, Ravi K; Blenis, John; Coull, Barry J; Murray, James T; van Steensel, Maurice Am; Wilkinson, Simon; Tee, Andrew R

    2014-10-01

    Birt-Hogg-Dubé (BHD) syndrome is a rare autosomal dominant condition caused by mutations in the FLCN gene and characterized by benign hair follicle tumors, pneumothorax, and renal cancer. Folliculin (FLCN), the protein product of the FLCN gene, is a poorly characterized tumor suppressor protein, currently linked to multiple cellular pathways. Autophagy maintains cellular homeostasis by removing damaged organelles and macromolecules. Although the autophagy kinase ULK1 drives autophagy, the underlying mechanisms are still being unraveled and few ULK1 substrates have been identified to date. Here, we identify that loss of FLCN moderately impairs basal autophagic flux, while re-expression of FLCN rescues autophagy. We reveal that the FLCN complex is regulated by ULK1 and elucidate 3 novel phosphorylation sites (Ser406, Ser537, and Ser542) within FLCN, which are induced by ULK1 overexpression. In addition, our findings demonstrate that FLCN interacts with a second integral component of the autophagy machinery, GABA(A) receptor-associated protein (GABARAP). The FLCN-GABARAP association is modulated by the presence of either folliculin-interacting protein (FNIP)-1 or FNIP2 and further regulated by ULK1. As observed by elevation of GABARAP, sequestome 1 (SQSTM1) and microtubule-associated protein 1 light chain 3 (MAP1LC3B) in chromophobe and clear cell tumors from a BHD patient, we found that autophagy is impaired in BHD-associated renal tumors. Consequently, this work reveals a novel facet of autophagy regulation by ULK1 and substantially contributes to our understanding of FLCN function by linking it directly to autophagy through GABARAP and ULK1.

  14. Brown adipose tissue regulates glucose homeostasis and insulin sensitivity

    OpenAIRE

    Stanford, Kristin I.; Middelbeek, Roeland J.W.; Townsend, Kristy L.; An, Ding; Nygaard, Eva B.; Hitchcox, Kristen M.; Markan, Kathleen R.; Nakano, Kazuhiro; Hirshman, Michael F.; Tseng, Yu-Hua; Goodyear, Laurie J.

    2012-01-01

    Brown adipose tissue (BAT) is known to function in the dissipation of chemical energy in response to cold or excess feeding, and also has the capacity to modulate energy balance. To test the hypothesis that BAT is fundamental to the regulation of glucose homeostasis, we transplanted BAT from male donor mice into the visceral cavity of age- and sex-matched recipient mice. By 8–12 weeks following transplantation, recipient mice had improved glucose tolerance, increased insulin sensitivity, lowe...

  15. Hkat, a novel nutritionally regulated transmembrane protein in adipose tissues

    OpenAIRE

    Ren Zhang

    2012-01-01

    White adipose tissue is an active endocrine organ regulating many aspects of whole body physiology and pathology. Adipogenesis, a process in which premature cells differentiate into adipocytes, is a complex process that includes orchestrated changes in gene expression and cell morphology in response to various nutritional and hormonal stimuli. To profile transcriptome changes in response to nutritional stimulation, we performed RNA-seq on fat in mice treated with either a high-fat diet or fas...

  16. Complex regulation of autophagy in cancer - integrated approaches to discover the networks that hold a double-edged sword.

    Science.gov (United States)

    Kubisch, János; Türei, Dénes; Földvári-Nagy, László; Dunai, Zsuzsanna A; Zsákai, Lilian; Varga, Máté; Vellai, Tibor; Csermely, Péter; Korcsmáros, Tamás

    2013-08-01

    Autophagy, a highly regulated self-degradation process of eukaryotic cells, is a context-dependent tumor-suppressing mechanism that can also promote tumor cell survival upon stress and treatment resistance. Because of this ambiguity, autophagy is considered as a double-edged sword in oncology, making anti-cancer therapeutic approaches highly challenging. In this review, we present how systems-level knowledge on autophagy regulation can help to develop new strategies and efficiently select novel anti-cancer drug targets. We focus on the protein interactors and transcriptional/post-transcriptional regulators of autophagy as the protein and regulatory networks significantly influence the activity of core autophagy proteins during tumor progression. We list several network resources to identify interactors and regulators of autophagy proteins. As in silico analysis of such networks often necessitates experimental validation, we briefly summarize tractable model organisms to examine the role of autophagy in cancer. We also discuss fluorescence techniques for high-throughput monitoring of autophagy in humans. Finally, the challenges of pharmacological modulation of autophagy are reviewed. We suggest network-based concepts to overcome these difficulties. We point out that a context-dependent modulation of autophagy would be favored in anti-cancer therapy, where autophagy is stimulated in normal cells, while inhibited only in stressed cancer cells. To achieve this goal, we introduce the concept of regulo-network drugs targeting specific transcription factors or miRNA families identified with network analysis. The effect of regulo-network drugs propagates indirectly through transcriptional or post-transcriptional regulation of autophagy proteins, and, as a multi-directional intervention tool, they can both activate and inhibit specific proteins in the same time. The future identification and validation of such regulo-network drug targets may serve as novel intervention

  17. Acetyl-coenzyme A: a metabolic master regulator of autophagy and longevity.

    Science.gov (United States)

    Schroeder, Sabrina; Pendl, Tobias; Zimmermann, Andreas; Eisenberg, Tobias; Carmona-Gutierrez, Didac; Ruckenstuhl, Christoph; Mariño, Guillermo; Pietrocola, Federico; Harger, Alexandra; Magnes, Christoph; Sinner, Frank; Pieber, Thomas R; Dengjel, Jörn; Sigrist, Stephan J; Kroemer, Guido; Madeo, Frank

    2014-07-01

    As the major lysosomal degradation pathway, autophagy represents the guardian of cellular homeostasis, removing damaged and potentially harmful material and replenishing energy reserves in conditions of starvation. Given its vast physiological importance, autophagy is crucially involved in the process of aging and associated pathologies. Although the regulation of autophagy strongly depends on nutrient availability, specific metabolites that modulate autophagic responses are poorly described. Recently, we revealed nucleo-cytosolic acetyl-coenzyme A (AcCoA) as a phylogenetically conserved inhibitor of starvation-induced and age-associated autophagy. AcCoA is the sole acetyl-group donor for protein acetylation, explaining why pharmacological or genetic manipulations that modify the concentrations of nucleo-cytosolic AcCoA directly affect the levels of protein acetylation. The acetylation of histones and cytosolic proteins inversely correlates with the rate of autophagy in yeast and mammalian cells, respectively, despite the fact that the routes of de novo AcCoA synthesis differ across phyla. Thus, we propose nucleo-cytosolic AcCoA to act as a conserved metabolic rheostat, linking the cellular metabolic state to the regulation of autophagy via effects on protein acetylation.

  18. Autophagy regulates chlorpyrifos-induced apoptosis in SH-SY5Y cells

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hyeon [Department of Pharmacology, College of Medicine, Hanyang University (Korea, Republic of); Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul (Korea, Republic of); Lee, Jeong Eun [Department of Pharmacology, College of Medicine, Hanyang University (Korea, Republic of); Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Shin, In Chul [Department of Pharmacology, College of Medicine, Hanyang University (Korea, Republic of); Koh, Hyun Chul, E-mail: hckoh@hanyang.ac.kr [Department of Pharmacology, College of Medicine, Hanyang University (Korea, Republic of); Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul (Korea, Republic of)

    2013-04-01

    Recent studies have shown that up-regulation of autophagy may be a tractable therapeutic intervention for clearing disease-causing proteins, including α-synuclein, ubiquitin, and other misfolded or aggregated proteins in pesticide-induced neurodegeneration. In a previous study, we reported that chlorpyrifos (CPF)-induced mitochondria-dependent apoptosis is mediated through reactive oxygen species in SH-SY5Y cells. In this study, we explored a novel pharmacotherapeutic approach to prevent CPF neurotoxicity involving the regulation of autophagy. We investigated the modulation of CPF-induced apoptosis according to autophagy regulation. We found that CPF induced apoptosis in SH-SY5Y cells, as demonstrated by the activation of caspase-3 and nuclear condensation. In addition, we observed that cells treated with CPF underwent autophagic cell death by monitoring the expression of LC3-II and p62. Pretreatment with the autophagy inducer rapamycin significantly enhanced the cell viability of CPF-exposed cells, and the enhancement of cell viability was partially due to alleviation of CPF-induced apoptosis via a decrease in levels of cleaved caspase-3. Specifically, rapamycin pretreatment decreased Bax and increased Bcl-2 expression in mitochondria. In addition, rapamycin significantly decreased cytochrome c release in from mitochondria into the cytosol. However, pretreatment of cells with the autophagy inhibitor, 3-methyladenine (3MA), remarkably increased CPF toxicity in these cells; this with correlated with increased expression of Bax and decreased expression of Bcl-2 in mitochondria. Our results suggest that CPF-induced cytotoxicity is modified by autophagy regulation and that rapamycin protects against CPF-induced apoptosis by enhancing autophagy. Pharmacologic induction of autophagy by rapamycin may be a useful treatment strategy in neurodegenerative disorders. - Highlights: ► Chlorpyrifos (CPF) is cytotoxic to SH-SY5Y cells ► CPF-induced cytotoxicity is mediated by

  19. Methylprednisolone exerts neuroprotective effects by regulating autophagy and apoptosis

    Institute of Scientific and Technical Information of China (English)

    Wei Gao; Shu-rui Chen; Meng-yao Wu; Kai Gao; Yuan-long Li; Hong-yu Wang; Chen-yuan Li; Hong Li

    2016-01-01

    Methylprednisolone markedly reduces autophagy and apoptosis after secondary spinal cord injury. Here, we investigated whether pretreat-ment of cells with methylprednisolone would protect neuron-like cells from subsequent oxidative damagevia suppression of autophagy and apoptosis. Cultured N2a cells were pretreated with 10 µM methylprednisolone for 30 minutes, then exposed to 100 µM H2O2 for 24 hours. Inverted phase contrast microscope images, MTT assay, lfow cytometry and western blot results showed that, compared to cells ex-posed to 100 µM H2O2 alone, cells pretreated with methylprednisolone had a signiifcantly lower percentage of apoptotic cells, maintained a healthy morphology, and showed downregulation of autophagic protein light chain 3B and Beclin-1 protein expression. These ifndings indicate that methylprednisolone exerted neuroprotective effects against oxidative damage by suppressing autophagy and apoptosis.

  20. Mevalonate cascade regulation of airway mesenchymal cell autophagy and apoptosis: a dual role for p53.

    Directory of Open Access Journals (Sweden)

    Saeid Ghavami

    Full Text Available Statins inhibit the proximal steps of cholesterol biosynthesis, and are linked to health benefits in various conditions, including cancer and lung disease. We have previously investigated apoptotic pathways triggered by statins in airway mesenchymal cells, and identified reduced prenylation of small GTPases as a primary effector mechanism leading to p53-mediated cell death. Here, we extend our studies of statin-induced cell death by assessing endpoints of both apoptosis and autophagy, and investigating their interplay and coincident regulation. Using primary cultured human airway smooth muscle (HASM and human airway fibroblasts (HAF, autophagy, and autophagosome formation and flux were assessed by transmission electron microscopy, cytochemistry (lysosome number and co-localization with LC3 and immunoblotting (LC3 lipidation and Atg12-5 complex formation. Chemical inhibition of autophagy increased simvastatin-induced caspase activation and cell death. Similarly, Atg5 silencing with shRNA, thus preventing Atg5-12 complex formation, increased pro-apoptotic effects of simvastatin. Simvastatin concomitantly increased p53-dependent expression of p53 up-regulated modulator of apoptosis (PUMA, NOXA, and damage-regulated autophagy modulator (DRAM. Notably both mevalonate cascade inhibition-induced autophagy and apoptosis were p53 dependent: simvastatin increased nuclear p53 accumulation, and both cyclic pifithrin-α and p53 shRNAi partially inhibited NOXA, PUMA expression and caspase-3/7 cleavage (apoptosis and DRAM expression, Atg5-12 complex formation, LC3 lipidation, and autophagosome formation (autophagy. Furthermore, the autophagy response is induced rapidly, significantly delaying apoptosis, suggesting the existence of a temporally coordinated p53 regulation network. These findings are relevant for the development of statin-based therapeutic approaches in obstructive airway disease.

  1. Age-regulated function of autophagy in the mouse inner ear.

    Science.gov (United States)

    de Iriarte Rodríguez, Rocío; Pulido, Sara; Rodríguez-de la Rosa, Lourdes; Magariños, Marta; Varela-Nieto, Isabel

    2015-12-01

    Autophagy is a highly conserved catabolic process essential for embryonic development and adult homeostasis. The autophagic machinery supplies energy by recycling intracellular components and facilitates the removal of apoptotic cells. In the inner ear, autophagy has been reported to play roles during early development in the chicken embryo and in the response to otic injury in the adult mouse. However, there are no studies on the expression of the autophagy machinery in the postnatal and adult inner ear. Insulin-like growth factor 1 (IGF-1) is one of the factors that regulate both otic development and cochlear postnatal maturation and function. Here, we hypothesised that autophagy could be one of the processes involved in the cochlear development and functional maturation. We report that autophagy-related genes (ATG) Becn1, Atg4g and Atg5 are expressed in the mouse cochlea, vestibular system and brainstem cochlear nuclei from late developmental stages to adulthood. Atg9 was studied in the mouse cochlea and showed a similar pattern. The presence of autophagic flux was confirmed by decreased sequestosome 1 (SQSTM1/p62) and increased relative levels of microtubule-associated protein light chain 3-II (LC3-II). Inner ear autophagy flux is developmentally regulated and is lower at perinatal stages than in the adult mouse, where an expression plateau is reached at the age of two-months, coinciding with the age at which full functional activity is reached. Expression is maintained in adult mice and declines after the age of twelve months. LC3B labelling showed that autophagy was primarily associated with spiral ganglion neurons. Over time, Igf1 wild type mice showed lower expression of genes coding for IGF-1 high affinity receptor and the family factor IGF-2 than null mice. Parallel analysis of autophagy machinery gene expression showed no significant differences between the genotypes over the lifespan of the null mice. Taken together, these results show that the

  2. Prolactin (PRL) in adipose tissue: regulation and functions.

    Science.gov (United States)

    Ben-Jonathan, Nira; Hugo, Eric

    2015-01-01

    New information concerning the effects of prolactin (PRL) on metabolic processes warrants reevaluation of its overall metabolic actions. PRL affects metabolic homeostasis by regulating key enzymes and transporters associated with glucose and lipid metabolism in several target organs. In the lactating mammary gland, PRL increases the production of milk proteins, lactose, and lipids. In adipose tissue, PRL generally suppresses lipid storage and adipokine release and affect adipogenesis. A specific case is made for PRL in the human breast and adipose tissues, where it acts as a circulating hormone and an autocrine/paracrine factor. Although its overall effects on body composition are both modest and species-specific, PRL may be involved in the manifestation of insulin resistance.

  3. Intrinsic regulation of blood flow in adipose tissue

    DEFF Research Database (Denmark)

    Henriksen, O; Nielsen, Steen Levin; Paaske, W

    1976-01-01

    Previous studies on intact human subcutaneous tissue have shown, that blood flow remains constant during minor changes in perfusion pressure. This so-called autoregulatory response has not been demonstrable in isolated preparations of adipose tissue. In the present study on isolated, denervated...... vasoconstriction with pronounced flow reduction. These two reactions may be important for local regulation of blood flow in subcutaneous tissue during orthostatic changes in arterial and venous pressure. It is concluded that the response in adipose tissue to changes in arterial pressure (autoregulation), venous...... subcutaneous tissue in female rabbits only 2 of 12 expts. revealed an autoregulatory response during reduction in arterial perfusion pressure. Effluent blood flow from the tissue in the control state was 15.5 ml/100 g-min (S.D. 6.4, n = 12) corresponding to slight vasodilatation of the exposed tissue...

  4. Role and Regulation of Autophagy in Heat Stress Responses of Tomato Plants

    Directory of Open Access Journals (Sweden)

    Jie eZhou

    2014-04-01

    Full Text Available As sessile organisms, plants are constantly exposed to a wide spectrum of stress conditions such as high temperature, which causes protein misfolding. Misfolded proteins are highly toxic and must be efficiently removed to reduce cellular proteotoxic stress if restoration of native conformations is unsuccessful. Although selective autophagy is known to function in protein quality control by targeting degradation of misfolded and potentially toxic proteins, its role and regulation in heat stress responses have not been analyzed in crop plants. In the present study, we found that heat stress induced expression of autophagy-related (ATG genes and accumulation of autophagosomes in tomato plants. Virus-induced gene silencing of tomato ATG5 and ATG7 genes resulted in increased sensitivity of tomato plants to heat stress based on both increased development of heat stress symptoms and compromised photosynthetic parameters of heat-stressed leaf tissues. Silencing of tomato homologs for the selective autophagy receptor NBR1, which targets ubiquitinated protein aggregates, also compromised tomato heat tolerance. To better understand the regulation of heat-induced autophagy, we found that silencing of tomato ATG5, ATG7 or NBR1 compromised heat-induced expression of not only the targeted genes but also other autophagy-related genes. Furthermore, we identified two tomato genes encoding proteins highly homologous to Arabidopsis WRKY33 transcription factor, which has been previously shown to interact physically with an autophagy protein. Silencing of tomato WRKY33 genes compromised tomato heat tolerance and reduced heat-induced ATG gene expression and autophagosome accumulation. Based on these results, we propose that heat-induced autophagy in tomato is subject to cooperative regulation by both WRKY33 and ATG proteins and plays a critical role in tomato heat tolerance, mostly likely through selective removal of heat-induced protein aggregates.

  5. Role and regulation of autophagy in heat stress responses of tomato plants.

    Science.gov (United States)

    Zhou, Jie; Wang, Jian; Yu, Jing-Quan; Chen, Zhixiang

    2014-01-01

    As sessile organisms, plants are constantly exposed to a wide spectrum of stress conditions such as high temperature, which causes protein misfolding. Misfolded proteins are highly toxic and must be efficiently removed to reduce cellular proteotoxic stress if restoration of native conformations is unsuccessful. Although selective autophagy is known to function in protein quality control by targeting degradation of misfolded and potentially toxic proteins, its role and regulation in heat stress responses have not been analyzed in crop plants. In the present study, we found that heat stress induced expression of autophagy-related (ATG) genes and accumulation of autophagosomes in tomato plants. Virus-induced gene silencing (VIGS) of tomato ATG5 and ATG7 genes resulted in increased sensitivity of tomato plants to heat stress based on both increased development of heat stress symptoms and compromised photosynthetic parameters of heat-stressed leaf tissues. Silencing of tomato homologs for the selective autophagy receptor NBR1, which targets ubiquitinated protein aggregates, also compromised tomato heat tolerance. To better understand the regulation of heat-induced autophagy, we found that silencing of tomato ATG5, ATG7, or NBR1 compromised heat-induced expression of not only the targeted genes but also other autophagy-related genes. Furthermore, we identified two tomato genes encoding proteins highly homologous to Arabidopsis WRKY33 transcription factor, which has been previously shown to interact physically with an autophagy protein. Silencing of tomato WRKY33 genes compromised tomato heat tolerance and reduced heat-induced ATG gene expression and autophagosome accumulation. Based on these results, we propose that heat-induced autophagy in tomato is subject to cooperative regulation by both WRKY33 and ATG proteins and plays a critical role in tomato heat tolerance, mostly likely through selective removal of heat-induced protein aggregates.

  6. TBC1D14 regulates autophagy via the TRAPP complex and ATG9 traffic.

    Science.gov (United States)

    Lamb, Christopher A; Nühlen, Stefanie; Judith, Delphine; Frith, David; Snijders, Ambrosius P; Behrends, Christian; Tooze, Sharon A

    2016-02-01

    Macroautophagy requires membrane trafficking and remodelling to form the autophagosome and deliver its contents to lysosomes for degradation. We have previously identified the TBC domain-containing protein, TBC1D14, as a negative regulator of autophagy that controls delivery of membranes from RAB11-positive recycling endosomes to forming autophagosomes. In this study, we identify the TRAPP complex, a multi-subunit tethering complex and GEF for RAB1, as an interactor of TBC1D14. TBC1D14 binds to the TRAPP complex via an N-terminal 103 amino acid region, and overexpression of this region inhibits both autophagy and secretory traffic. TRAPPC8, the mammalian orthologue of a yeast autophagy-specific TRAPP subunit, forms part of a mammalian TRAPPIII-like complex and both this complex and TBC1D14 are needed for RAB1 activation. TRAPPC8 modulates autophagy and secretory trafficking and is required for TBC1D14 to bind TRAPPIII. Importantly, TBC1D14 and TRAPPIII regulate ATG9 trafficking independently of ULK1. We propose a model whereby TBC1D14 and TRAPPIII regulate a constitutive trafficking step from peripheral recycling endosomes to the early Golgi, maintaining the cycling pool of ATG9 required for initiation of autophagy. PMID:26711178

  7. Protein kinase B/Akt1 inhibits autophagy by down-regulating UVRAG expression

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wonseok; Ju, Ji-hyun; Lee, Kyung-min; Nam, KeeSoo; Oh, Sunhwa [Department of Life Science, College of Natural Science, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Shin, Incheol, E-mail: incheol@hanyang.ac.kr [Department of Life Science, College of Natural Science, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)

    2013-02-01

    Autophagy, or autophagocytosis, is a selective intracellular degradative process involving the cell's own lysosomal apparatus. An essential component in cell development, homeostasis, repair and resistance to stress, autophagy may result in either cell death or survival. The targeted region of the cell is sequestered within a membrane structure, the autophagosome, for regulation of the catabolic process. A key factor in both autophagosome formation and autophagosome maturation is a protein encoded by the ultraviolet irradiation resistance-associated gene (UVRAG). Conversely, the serine/threonine-specific protein kinase B (PKB, also known as Akt), which regulates survival in various cancers, inhibits autophagy through mTOR activation. We found that Akt1 may also directly inhibit autophagy by down-regulating UVRAG both in a 293T transient transfection system and breast cancer cells stably expressing Akt1. The UVRAG with mutations at putative Akt1-phosphorylation sites were still inhibited by Akt1, and dominant-negative Akt1 also inhibited UVRAG expression, suggesting that Akt1 down-regulates UVRAG by a kinase activity-independent mechanism. We showed that Akt1 overexpression in MDA-MB-231 breast cancer cells down-regulated UVRAG transcription. Cells over-expressing Akt1 were more resistant than control cells to ultraviolet light-induced autophagy and exhibited the associated reduction in cell viability. Levels of the autophagosome indicator protein LC3B-II and mRFP-GFP-LC3 were reduced in cells that over-expressing Akt1. Inhibiting Akt1 by siRNA or reintroducing UVRAG gene rescued the level of LC3B-II in UV-irradiation. Altogether, these data suggest that Akt1 may inhibit autophagy by decreasing UVRAG expression, which also sensitizes cancer cells to UV irradiation.

  8. Visceral periadventitial adipose tissue regulates arterial tone of mesenteric arteries.

    Science.gov (United States)

    Verlohren, Stefan; Dubrovska, Galyna; Tsang, Suk-Ying; Essin, Kirill; Luft, Friedrich C; Huang, Yu; Gollasch, Maik

    2004-09-01

    Periadventitial adipose tissue produces vasoactive substances that influence vascular contraction. Earlier studies addressed this issue in aorta, a vessel that does not contribute to peripheral vascular resistance. We tested the hypothesis that periadventitial adipose tissue modulates contraction of smaller arteries more relevant to blood pressure regulation. We studied mesenteric artery rings surrounded by periadventitial adipose tissue from adult male Sprague-Dawley rats. The contractile response to serotonin, phenylephrine, and endothelin I was markedly reduced in intact vessels compared with vessels without periadventitial fat. The contractile response to U46619 or depolarizing high K+-containing solutions (60 mmol/L) was similar in vessels with and without periadventitial fat. The K+ channel opener cromakalim induced relaxation of vessels precontracted by serotonin but not by U46619 or high K+-containing solutions (60 mmol/L), suggesting that K+ channels are involved. The intracellular membrane potential of smooth muscle cells was more hyperpolarized in intact vessels than in vessels without periadventitial fat. Both the anticontractile effect and membrane hyperpolarization of periadventitial fat were abolished by inhibition of delayed-rectifier K+ (K(v)) channels with 4-aminopyridine (2 mmol/L) or 3,4-diaminopyridine (1 mmol/L). Blocking other K+ channels with glibenclamide (3 micromol/L), apamin (1 micromol/L), iberiotoxin (100 nmol/L), tetraethylammonium ions (1 mmol/L), tetrapentylammonium ions (10 micromol/L), or Ba2+ (3 micromol/L) had no effect. Longitudinal removal of half the perivascular tissue reduced the anticontractile effect of fat by almost 50%, whereas removal of the endothelium had no effect. We suggest that visceral periadventitial adipose tissue controls mesenteric arterial tone by inducing vasorelaxation via K(v) channel activation in vascular smooth muscle cells. PMID:15302842

  9. Effects of autophagy regulation of tumor-associated macrophages on radiosensitivity of colorectal cancer cells.

    Science.gov (United States)

    Shao, Le-Ning; Zhu, Bao-Song; Xing, Chun-Gen; Yang, Xiao-Dong; Young, Wu; Cao, Jian-Ping

    2016-03-01

    Tumor‑associated macrophages (TAMs), a major component of the tumor microenvironment, are crucial to the processes of tumor growth, infiltration and metastasis, and contribute to drug resistance. The importance of TAMs in radiation resistance of colorectal cancer remains unclear. To investigate the effects of autophagy regulation of TAMs on the radiosensitivity of colorectal cancer cells, the current study induced TAM formation from THP‑1 monocyte cells. Sequential treatment of THP‑1 cells with PMA for 72 h and human recombinant interleukin‑4 for 24 h was used to stimulate THP‑1 differentiation to TAMs. Expression of the cell surface markers CD68, CD204 and CD206, and changes to cell morphology were used to confirm successful differentiation. The TAMs were stimulated to promote or inhibit autophagy during co‑culture with LoVo colorectal adenocarcinoma cells. The cells were irradiated, with subsequent measurement of LoVo colony formation and apoptosis. Additionally, the expression of p53, Bcl‑2, survivin and Smac proteins was assessed by western blotting. Monodansylcadaverin staining was used to analyze the presence of autophagic vacuoles in TAM, and western blot analysis was used to assess the expression of Beclin‑1, LC3B I and II, ATG‑3, ‑5 and ‑7. The results demonstrated TAM autophagy to be markedly altered by rapamycin and bafilomycin A1 treatment. Following co‑culture with TAMs, the colony formation rate and survival fraction of LoVo cells were significantly higher than those in the control group (PLoVo colorectal cancer cells. Upregulation of TAM autophagy using rapamycin exhibited more effective inhibition of LoVo colony formation than autophagy downregulation. Notably, apoptosis was significantly increased in LoVo cells when co‑cultured with TAMs only, or with rapamycin‑mediated autophagy upregulated TAMs, compared with LoVo cells cultured alone (PLoVo cells co‑cultured with TAMs, compared with the control group (P<0

  10. Autophagy regulates Wolbachia populations across diverse symbiotic associations

    OpenAIRE

    Voronin, Denis; Cook, Darren A. N.; Steven, Andrew; Taylor, Mark J

    2012-01-01

    Wolbachia are widespread and abundant intracellular symbionts of arthropods and filarial nematodes. Their symbiotic relationships encompass obligate mutualism, commensalism, parasitism, and pathogenicity. A consequence of these diverse associations is that Wolbachia encounter a wide range of host cells and intracellular immune defense mechanisms of invertebrates, which they must evade to maintain their populations and spread to new hosts. Here we show that autophagy, a conserved intracellular...

  11. Modulation of glutamine metabolism by the PI(3)K-PKB-FOXO network regulates autophagy

    NARCIS (Netherlands)

    van der Vos, Kristan E.; Eliasson, Pernilla; Proikas-Cezanne, Tassula; Vervoort, Stephin J.; van Boxtel, Ruben; Putker, Marrit; van Zutphen, Iris J.; Mauthe, Mario; Zellmer, Sebastian; Pals, Cornelieke; Verhagen, Liesbeth P.; Koerkamp, Marian J. A. Groot; Braat, A. Koen; Dansen, Tobias B.; Holstege, Frank C.; Gebhardt, Rolf; Burgering, Boudewijn M.; Coffer, Paul J.

    2012-01-01

    The PI(3)K-PKB-FOXO signalling network provides a major intracellular hub for the regulation of cell proliferation, survival and stress resistance. Here we report an unexpected role for FOXO transcription factors inregulating autophagy by modulating intracellular glutamine levels. To identify transc

  12. SYK regulates macrophage MHC-II expression via activation of autophagy in response to oxidized LDL

    Science.gov (United States)

    Choi, Soo-Ho; Gonen, Ayelet; Diehl, Cody J; Kim, Jungsu; Almazan, Felicidad; Witztum, Joseph L; Miller, Yury I

    2015-01-01

    Adaptive immunity, which plays an important role in the development of atherosclerosis, is mediated by major histocompatibility complex (MHC)-dependent antigen presentation. In atherosclerotic lesions, macrophages constitute an important class of antigen-presenting cells that activate adaptive immune responses to oxidized low-density lipoprotein (OxLDL). It has been reported that autophagy regulates adaptive immune responses by enhancing antigen presentation to MHC class II (MHC-II). In a previous study, we have demonstrated that SYK (spleen tyrosine kinase) regulates generation of reactive oxygen species (ROS) and activation of MAPK8/JNK1 in macrophages. Because ROS and MAPK8 are known to regulate autophagy, in this study we investigated the role of SYK in autophagy, MHC-II expression and adaptive immune response to OxLDL. We demonstrate that OxLDL induces autophagosome formation, MHC-II expression, and phosphorylation of SYK in macrophages. Gene knockout and pharmacological inhibitors of NOX2 and MAPK8 reduced OxLDL-induced autophagy. Using bone marrow-derived macrophages isolated from wild-type and myeloid-specific SYK knockout mice, we demonstrate that SYK regulates OxLDL-induced ROS generation, MAPK8 activation, BECN1-BCL2 dissociation, autophagosome formation and presentation of OxLDL-derived antigens to CD4+ T cells. ldlr−/− syk−/− mice fed a high-fat diet produced lower levels of IgG to malondialdehyde (MDA)-LDL, malondialdehyde-acetaldehyde (MAA)-LDL, and OxLDL compared to ldlr−/− mice. These results provide new insights into the mechanisms by which SYK regulates MHC-II expression via autophagy in macrophages and may contribute to regulation of adaptive immune responses in atherosclerosis. PMID:25946330

  13. SYK regulates macrophage MHC-II expression via activation of autophagy in response to oxidized LDL.

    Science.gov (United States)

    Choi, Soo-Ho; Gonen, Ayelet; Diehl, Cody J; Kim, Jungsu; Almazan, Felicidad; Witztum, Joseph L; Miller, Yury I

    2015-01-01

    Adaptive immunity, which plays an important role in the development of atherosclerosis, is mediated by major histocompatibility complex (MHC)-dependent antigen presentation. In atherosclerotic lesions, macrophages constitute an important class of antigen-presenting cells that activate adaptive immune responses to oxidized low-density lipoprotein (OxLDL). It has been reported that autophagy regulates adaptive immune responses by enhancing antigen presentation to MHC class II (MHC-II). In a previous study, we have demonstrated that SYK (spleen tyrosine kinase) regulates generation of reactive oxygen species (ROS) and activation of MAPK8/JNK1 in macrophages. Because ROS and MAPK8 are known to regulate autophagy, in this study we investigated the role of SYK in autophagy, MHC-II expression and adaptive immune response to OxLDL. We demonstrate that OxLDL induces autophagosome formation, MHC-II expression, and phosphorylation of SYK in macrophages. Gene knockout and pharmacological inhibitors of NOX2 and MAPK8 reduced OxLDL-induced autophagy. Using bone marrow-derived macrophages isolated from wild-type and myeloid-specific SYK knockout mice, we demonstrate that SYK regulates OxLDL-induced ROS generation, MAPK8 activation, BECN1-BCL2 dissociation, autophagosome formation and presentation of OxLDL-derived antigens to CD4(+) T cells. ldlr(-/-) syk(-/-) mice fed a high-fat diet produced lower levels of IgG to malondialdehyde (MDA)-LDL, malondialdehyde-acetaldehyde (MAA)-LDL, and OxLDL compared to ldlr(-/-) mice. These results provide new insights into the mechanisms by which SYK regulates MHC-II expression via autophagy in macrophages and may contribute to regulation of adaptive immune responses in atherosclerosis.

  14. New Potential Pharmacological Functions of Chinese Herbal Medicines via Regulation of Autophagy

    Directory of Open Access Journals (Sweden)

    Betty Yuen Kwan Law

    2016-03-01

    Full Text Available Autophagy is a universal catabolic cellular process for quality control of cytoplasm and maintenance of cellular homeostasis upon nutrient deprivation and environmental stimulus. It involves the lysosomal degradation of cellular components such as misfolded proteins or damaged organelles. Defects in autophagy are implicated in the pathogenesis of diseases including cancers, myopathy, neurodegenerations, infections and cardiovascular diseases. In the recent decade, traditional drugs with new clinical applications are not only commonly found in Western medicines, but also highlighted in Chinese herbal medicines (CHM. For instance, pharmacological studies have revealed that active components or fractions from Chaihu (Radix bupleuri, Hu Zhang (Rhizoma polygoni cuspidati, Donglingcao (Rabdosia rubesens, Hou po (Cortex magnoliae officinalis and Chuan xiong (Rhizoma chuanxiong modulate cancers, neurodegeneration and cardiovascular disease via autophagy. These findings shed light on the potential new applications and formulation of CHM decoctions via regulation of autophagy. This article reviews the roles of autophagy in the pharmacological actions of CHM and discusses their new potential clinical applications in various human diseases.

  15. Cathepsin-B-mediated cleavage of Disabled-2 regulates TGF-β-induced autophagy.

    Science.gov (United States)

    Jiang, Yong; Woosley, Alec N; Sivalingam, Nageswaran; Natarajan, Sneha; Howe, Philip H

    2016-08-01

    Transforming growth factor-β (TGF-β) induces the expression of Disabled-2 (Dab2), an endocytic adaptor and tumour suppressor, concomitant with the induction of an epithelial-mesenchymal transition (EMT) in mammary epithelial cells. Here we show that following TGF-β-mediated EMT, sustained TGF-β treatment leads to proteolytic degradation of Dab2 by cathepsin B (CTSB), loss of the mesenchymal phenotype and induction of autophagy. CTSB inhibition or expression of a CTSB-resistant Dab2 mutant maintains Dab2 expression and shifts long-term TGF-β-treated cells from autophagy to apoptosis. We further show that Dab2 interacts with Beclin-1 to promote casein-kinase-2-mediated phosphorylation of Beclin-1, preventing Beclin-1-Vps34 interaction and subsequent autophagosome assembly. Thus, CTSB-mediated degradation of Dab2 allows Beclin-1-Vps34 induction of autophagy, whereas sustained Dab2 expression prevents autophagy and promotes apoptosis by stabilizing the pro-apoptotic Bim protein. In vivo studies suggest that Dab2-mediated regulation of autophagy modulates chemotherapeutic resistance and tumour metastasis. PMID:27398911

  16. GABA in Paraventricular Nucleus Regulates Adipose Afferent Reflex in Rats.

    Directory of Open Access Journals (Sweden)

    Lei Ding

    Full Text Available Chemical stimulation of white adipose tissue (WAT induces adipose afferent reflex (AAR, and thereby causes a general sympathetic activation. Paraventricular nucleus (PVN is important in control of sympathetic outflow. This study was designed to investigate the role of γ-aminobutyric acid (GABA in PVN in regulating the AAR.Experiments were carried out in anesthetized rats. Renal sympathetic nerve activity (RSNA and mean arterial pressure (MAP were continuously recorded. AAR was evaluated by the RSNA and MAP responses to electrical stimulation of the right epididymal WAT (eWAT afferent nerve. Electrical stimulation of eWAT afferent nerve increase RSNA. Bilateral microinjection of the GABAA receptor agonist isoguvacine or the GABAB receptor agonist baclofen attenuated the AAR. The effect of isoguvacine on the AAR was greater than that of baclofen. The GABAA receptor antagonist gabazine enhanced the AAR, while the GABAB receptor antagonist CGP-35348 had no significant effect on the AAR. Bilateral PVN microinjection of vigabatrin, a selective GABA-transaminase inhibitor, to increase endogenous GABA levels in the PVN abolished the AAR. The inhibitory effect of vigabatrin on the AAR was attenuated by the pretreatment with gabazine or CGP-35348. Pretreatment with combined gabazine and CGP-35348 abolished the effects of vigabatrin.Activation of GABAA or GABAB receptors in the PVN inhibits the AAR. Blockade of GABAA receptors in the PVN enhances the AAR. Endogenous GABA in the PVN plays an important role in regulating the AAR.

  17. SIRT1 positively regulates autophagy and mitochondria function in embryonic stem cells under oxidative stress.

    Science.gov (United States)

    Ou, Xuan; Lee, Man Ryul; Huang, Xinxin; Messina-Graham, Steven; Broxmeyer, Hal E

    2014-05-01

    SIRT1, an NAD-dependent deacetylase, plays a role in regulation of autophagy. SIRT1 increases mitochondrial function and reduces oxidative stress, and has been linked to age-related reactive oxygen species (ROS) generation, which is highly dependent on mitochondrial metabolism. H2O2 induces oxidative stress and autophagic cell death through interference with Beclin 1 and the mTOR signaling pathways. We evaluated connections between SIRT1 activity and induction of autophagy in murine (m) and human (h) embryonic stem cells (ESCs) upon ROS challenge. Exogenous H2 O2 (1 mM) induced apoptosis and autophagy in wild-type (WT) and Sirt1-/- mESCs. High concentrations of H2O2 (1 mM) induced more apoptosis in Sirt1-/-, than in WT mESCs. However, addition of 3-methyladenine, a widely used autophagy inhibitor, in combination with H2O2 induced more cell death in WT than in Sirt1-/- mESCs. Decreased induction of autophagy in Sirt1-/- mESCs was demonstrated by decreased conversion of LC3-I to LC3-II, lowered expression of Beclin-1, and decreased LC3 punctae and LysoTracker staining. H2O2 induced autophagy with loss of mitochondrial membrane potential and disruption of mitochondrial dynamics in Sirt1-/- mESCs. Increased phosphorylation of P70/85-S6 kinase and ribosomal S6 was noted in Sirt1-/- mESCs, suggesting that SIRT1 regulates the mTOR pathway. Consistent with effects in mESCs, inhibition of SIRT1 using Lentivirus-mediated SIRT1 shRNA in hESCs demonstrated that knockdown of SIRT1 decreased H2O2-induced autophagy. This suggests a role for SIRT1 in regulating autophagy and mitochondria function in ESCs upon oxidative stress, effects mediated at least in part by the class III PI3K/Beclin 1 and mTOR pathways.

  18. Induction of autophagy by Imatinib sequesters Bcr-Abl in autophagosomes and down-regulates Bcr-Abl protein.

    LENUS (Irish Health Repository)

    Elzinga, Baukje M

    2013-06-01

    Chronic Myeloid Leukemia (CML) is a disease of hematopoietic stem cells which harbor the chimeric gene Bcr-Abl. Expression levels of this constitutively active tyrosine kinase are critical for response to tyrosine kinase inhibitor treatment and also disease progression, yet the regulation of protein stability is poorly understood. We have previously demonstrated that imatinib can induce autophagy in Bcr-Abl expressing cells. Autophagy has been associated with the clearance of large macromolecular signaling complexes and abnormal proteins, however, the contribution of autophagy to the turnover of Bcr-Abl protein in imatinib treated cells is unknown. In this study, we show that following imatinib treatment, Bcr-Abl is sequestered into vesicular structures that co-localize with the autophagy marker LC3 or GABARAP. This association is inhibited by siRNA mediated knockdown of autophagy regulators (Beclin 1\\/ATG7). Pharmacological inhibition of autophagy also reduced Bcr-Abl\\/LC3 co-localization in both K562 and CML patient cells. Bcr-Abl protein expression was reduced with imatinib treatment. Inhibition of both autophagy and proteasome activity in imatinib treated cells was required to restore Bcr-Abl protein levels to those of untreated cells. This ability to down-regulate Bcr-Abl protein levels through the induction of autophagy may be an additional and important feature of the activity of imatinib.

  19. Hypothalamic regulation of brown adipose tissue thermogenesis and energy homeostasis

    Directory of Open Access Journals (Sweden)

    Wei eZhang

    2015-08-01

    Full Text Available Obesity and diabetes are increasing at an alarming rate worldwide, but the strategies for the prevention and treatment of these disorders remain inadequate. Brown adipose tissue (BAT is important for cold protection by producing heat using lipids and glucose as metabolic fuels. This thermogenic action causes increased energy expenditure and significant lipid/glucose disposal. In addition, BAT in white adipose tissue (WAT or beige cells have been found and they also exhibit the thermogenic action similar to BAT. These data provide evidence indicating BAT/beige cells as a potential target for combating obesity and diabetes. Recent discoveries of active BAT and beige cells in adult humans have further highlighted this potential. Growing studies have also shown the importance of central nervous system in the control of BAT thermogenesis and WAT browning using animal models. This review is focused on central neural thermoregulation, particularly addressing our current understanding of the importance of hypothalamic neural signaling in the regulation of BAT/beige thermogenesis and energy homeostasis.

  20. Poly-ADP-ribosylation of HMGB1 regulates TNFSF10/TRAIL resistance through autophagy.

    Science.gov (United States)

    Yang, Minghua; Liu, Liying; Xie, Min; Sun, Xiaofang; Yu, Yan; Kang, Rui; Yang, Liangchun; Zhu, Shan; Cao, Lizhi; Tang, Daolin

    2015-01-01

    Both apoptosis ("self-killing") and autophagy ("self-eating") are evolutionarily conserved processes, and their crosstalk influences anticancer drug sensitivity and cell death. However, the underlying mechanism remains unclear. Here, we demonstrated that HMGB1 (high mobility group box 1), normally a nuclear protein, is a crucial regulator of TNFSF10/TRAIL (tumor necrosis factor [ligand] superfamily, member 10)-induced cancer cell death. Activation of PARP1 (poly [ADP-ribose] polymerase 1) was required for TNFSF10-induced ADP-ribosylation of HMGB1 in cancer cells. Moreover, pharmacological inhibition of PARP1 activity or knockdown of PARP1 gene expression significantly inhibited TNFSF10-induced HMGB1 cytoplasmic translocation and subsequent HMGB1-BECN1 complex formation. Furthermore, suppression of the PARP1-HMGB1 pathway diminished autophagy, increased apoptosis, and enhanced the anticancer activity of TNFSF10 in vitro and in a subcutaneous tumor model. These results indicate that PARP1 acts as a prominent upstream regulator of HMGB1-mediated autophagy and maintains a homeostatic balance between apoptosis and autophagy, which provides new insight into the mechanism of TNFSF10 resistance.

  1. Matrine-induced autophagy regulated by p53 through AMP-activated protein kinase in human hepatoma cells.

    Science.gov (United States)

    Xie, Shan-Bu; He, Xing-Xing; Yao, Shu-Kun

    2015-08-01

    Matrine, one of the main extract components of Sophora flavescens, has been shown to exhibit inhibitory effects on some tumors through autophagy. However, the mechanism underlying the effect of matrine remains unclear. The cultured human hepatocellular carcinoma cell line HepG2 and SMMC‑7721 were treated with matrine. Signal transduction and gene expression profile were determined. Matrine stimulated autophagy in SMMC‑7721 cells in a mammalian target of rapamycin (mTOR)-dependent manner, but in an mTOR-independent manner in HepG2 cells. Next, in HepG2 cells, autophagy induced by matrine was regulated by p53 inactivation through AMP-activated protein kinase (AMPK) signaling transduction, then AMPK suppression switched autophagy to apoptosis. Furthermore, the interferon (IFN)-inducible genes, including interferon α-inducible protein 27 (IFI27) and interferon induced transmembrane protein 1 (IFITM1), which are downstream effector of p53, might be modulated by matrine-induced autophagy. In addition, we found that the p53 protein isoforms, p53β, p53γ, ∆133p53, and ∆133p53γ, due to alternative splicing of intron 9, might be regulated by the p53-mediated autophagy. These results show that matrine induces autophagy in human hepatoma cells through a novel mechanism, which is p53/AMPK signaling pathway involvement in matrine-promoted autophagy.

  2. Hypothalamus-adipose tissue crosstalk: neuropeptide Y and the regulation of energy metabolism.

    Science.gov (United States)

    Zhang, Wei; Cline, Mark A; Gilbert, Elizabeth R

    2014-01-01

    Neuropeptide Y (NPY) is an orexigenic neuropeptide that plays a role in regulating adiposity by promoting energy storage in white adipose tissue and inhibiting brown adipose tissue activation in mammals. This review describes mechanisms underlying NPY's effects on adipose tissue energy metabolism, with an emphasis on cellular proliferation, adipogenesis, lipid deposition, and lipolysis in white adipose tissue, and brown fat activation and thermogenesis. In general, NPY promotes adipocyte differentiation and lipid accumulation, leading to energy storage in adipose tissue, with effects mediated mainly through NPY receptor sub-types 1 and 2. This review highlights hypothalamus-sympathetic nervous system-adipose tissue innervation and adipose tissue-hypothalamus feedback loops as pathways underlying these effects. Potential sources of NPY that mediate adipose effects include the bloodstream, sympathetic nerve terminals that innervate the adipose tissue, as well as adipose tissue-derived cells. Understanding the role of central vs. peripherally-derived NPY in whole-body energy balance could shed light on mechanisms underlying the pathogenesis of obesity. This information may provide some insight into searching for alternative therapeutic strategies for the treatment of obesity and associated diseases.

  3. Targeting γ-herpesvirus 68 Bcl-2-mediated down-regulation of autophagy.

    Science.gov (United States)

    Su, Minfei; Mei, Yang; Sanishvili, Ruslan; Levine, Beth; Colbert, Christopher L; Sinha, Sangita

    2014-03-21

    γ-herpesviruses (γHVs) are common human pathogens that encode homologs of the anti-apoptotic cellular Bcl-2 proteins, which are critical to viral reactivation and oncogenic transformation. The murine γHV68 provides a tractable in vivo model for understanding general features of these important human pathogens. Bcl-XL, a cellular Bcl-2 homolog, and the murine γHV68 Bcl-2 homolog, M11, both bind to a BH3 domain within the key autophagy effector Beclin 1 with comparable affinities, resulting in the down-regulation of Beclin 1-mediated autophagy. Despite this similarity, differences in residues lining the binding site of M11 and Bcl-XL dictate varying affinities for the different BH3 domain-containing proteins. Here we delineate Beclin 1 differential specificity determinants for binding to M11 or Bcl-XL by quantifying autophagy levels in cells expressing different Beclin 1 mutants and either M11 or Bcl-XL, and we show that a G120E/D121A Beclin 1 mutant selectively prevents down-regulation of Beclin 1-mediated autophagy by Bcl-XL, but not by M11. We use isothermal titration calorimetry to identify a Beclin 1 BH3 domain-derived peptide that selectively binds to M11, but not to Bcl-XL. The x-ray crystal structure of this peptide bound to M11 reveals the mechanism by which the M11 BH3 domain-binding groove accommodates this M11-specific peptide. This information was used to develop a cell-permeable peptide inhibitor that selectively inhibits M11-mediated, but not Bcl-XL-mediated, down-regulation of autophagy.

  4. The Ubiquitin Ligase Siah2 Regulates Obesity-induced Adipose Tissue Inflammation

    OpenAIRE

    Kilroy, Gail; Carter, Lauren E; Newman, Susan; Burk, David H.; Manuel, Justin; Möller, Andreas; Bowtell, David D.; Mynatt, Randall L.; Ghosh, Sujoy; Floyd, Z. Elizabeth

    2015-01-01

    Objective Chronic, low-grade adipose tissue inflammation associated with adipocyte hypertrophy is an important link in the relationship between obesity and insulin resistance. Although ubiquitin ligases regulate inflammatory processes, the role of these enzymes in metabolically driven adipose tissue inflammation is relatively unexplored. Herein, we examined the effect of the ubiquitin ligase Siah2 on obesity-related adipose tissue inflammation. Methods Wild-type and Siah2KO mice were fed a lo...

  5. A close connection between the PERK and IRE arms of the UPR and the transcriptional regulation of autophagy.

    Science.gov (United States)

    Deegan, Shane; Koryga, Izabela; Glynn, Sharon A; Gupta, Sanjeev; Gorman, Adrienne M; Samali, Afshin

    2015-01-01

    Endoplasmic reticulum (ER) stress is known to lead to activation of both the unfolded protein response (UPR) and autophagy. Although regulatory connections have been identified between the UPR and autophagy, it is still unclear to what extent the UPR regulates the genes involved at the different stages of the autophagy pathway. Here, we carried out a microarray analysis of HCT116 cells subjected to ER stress and observed the transcriptional upregulation of a large cohort of autophagy-related genes. Of particular interest, we identified the transcriptional upregulation of the autophagy receptor genes SQSTM1/p62, NBR1 and BNIP3L/NIX in response to ER stress and show that the inhibition of the UPR transmembrane receptors, PERK and IRE1, abrogates this upregulation. PMID:25475719

  6. MCOLN1 is a ROS sensor in lysosomes that regulates autophagy

    Science.gov (United States)

    Zhang, Xiaoli; Cheng, Xiping; Yu, Lu; Yang, Junsheng; Calvo, Raul; Patnaik, Samarjit; Hu, Xin; Gao, Qiong; Yang, Meimei; Lawas, Maria; Delling, Markus; Marugan, Juan; Ferrer, Marc; Xu, Haoxing

    2016-01-01

    Cellular stresses trigger autophagy to remove damaged macromolecules and organelles. Lysosomes ‘host' multiple stress-sensing mechanisms that trigger the coordinated biogenesis of autophagosomes and lysosomes. For example, transcription factor (TF)EB, which regulates autophagy and lysosome biogenesis, is activated following the inhibition of mTOR, a lysosome-localized nutrient sensor. Here we show that reactive oxygen species (ROS) activate TFEB via a lysosomal Ca2+-dependent mechanism independent of mTOR. Exogenous oxidants or increasing mitochondrial ROS levels directly and specifically activate lysosomal TRPML1 channels, inducing lysosomal Ca2+ release. This activation triggers calcineurin-dependent TFEB-nuclear translocation, autophagy induction and lysosome biogenesis. When TRPML1 is genetically inactivated or pharmacologically inhibited, clearance of damaged mitochondria and removal of excess ROS are blocked. Furthermore, TRPML1's ROS sensitivity is specifically required for lysosome adaptation to mitochondrial damage. Hence, TRPML1 is a ROS sensor localized on the lysosomal membrane that orchestrates an autophagy-dependent negative-feedback programme to mitigate oxidative stress in the cell. PMID:27357649

  7. Salinomycin activates AMP-activated protein kinase-dependent autophagy in cultured osteoblastoma cells: a negative regulator against cell apoptosis.

    Directory of Open Access Journals (Sweden)

    Lun-qing Zhu

    Full Text Available BACKGROUND: The malignant osteoblastoma has poor prognosis, thus the search for novel and more efficient chemo-agents against this disease is urgent. Salinomycin induces broad anti-cancer effects both in vivo and in vitro, however, its role in osteoblastoma is still not clear. KEY FINDINGS: Salinomycin induced both apoptosis and autophagy in cultured U2OS and MG-63 osteoblastoma cells. Inhibition of autophagy by 3-methyladenine (3-MA, or by RNA interference (RNAi of light chain 3B (LC3B, enhanced salinomycin-induced cytotoxicity and apoptosis. Salinomycin induced a profound AMP-activated protein kinase (AMPK activation, which was required for autophagy induction. AMPK inhibition by compound C, or by AMPKα RNAi prevented salinomycin-induced autophagy activation, while facilitating cancer cell death and apoptosis. On the other hand, the AMPK agonist AICAR promoted autophagy activation in U2OS cells. Salinomycin-induced AMPK activation was dependent on reactive oxygen species (ROS production in osteoblastoma cells. Antioxidant n-acetyl cysteine (NAC significantly inhibited salinomycin-induced AMPK activation and autophagy induction. CONCLUSIONS: Salinomycin activates AMPK-dependent autophagy in osteoblastoma cells, which serves as a negative regulator against cell apoptosis. AMPK-autophagy inhibition might be a novel strategy to sensitize salinomycin's effect in cancer cells.

  8. Oxidative Stress and Autophagy in the Regulation of Lysosome-Dependent Neuron Death

    OpenAIRE

    Pivtoraiko, Violetta N.; Stone, Sara L; Roth, Kevin A.; Shacka, John J

    2009-01-01

    Lysosomes critically regulate the pH-dependent catabolism of extracellular and intracellular macromolecules delivered from the endocytic/heterophagy and autophagy pathways, respectively. The importance of lysosomes to cell survival is underscored not only by their unique ability effectively to degrade metalloproteins and oxidatively damaged macromolecules, but also by the distinct potential for induction of both caspase-dependent and -independent cell death with a compromise in the integrity ...

  9. Role and Regulation of Autophagy in Heat Stress Responses of Tomato Plants

    OpenAIRE

    Jie eZhou; Jian eWang; Jingquan eYu; Zhixiang eChen

    2014-01-01

    As sessile organisms, plants are constantly exposed to a wide spectrum of stress conditions such as high temperature, which causes protein misfolding. Misfolded proteins are highly toxic and must be efficiently removed to reduce cellular proteotoxic stress if restoration of native conformations is unsuccessful. Although selective autophagy is known to function in protein quality control by targeting degradation of misfolded and potentially toxic proteins, its role and regulation in heat st...

  10. The Autophagy Regulator Rubicon Is a Feedback Inhibitor of CARD9-Mediated Host Innate Immunity

    OpenAIRE

    Yang, Chul-Su; Rodgers, Mary; Min, Chan-Ki; Lee, Jong-Soo; Kingeter, Lara; Lee, June-Yong; Jong, Ambrose; Kramnik, Igor; Lin, Xin; Jung, Jae U.

    2012-01-01

    Assembly of a scaffold consisting of CARD9, BCL10, and MALT1 (CBM complex) is critical for effective signaling by multiple pattern recognition receptors (PRRs) including Dectin and RIG-I. The RUN domain Beclin-1-interacting cysteine-rich-containing Rubicon protein associates constitutively with the Beclin-UVRAG-Vps34 complex under normal conditions to regulate autophagy. Rubicon also interacts with the phagocytic NADPH-oxidase complex upon TLR stimulation to induce potent antimicrobial respon...

  11. C-myb Regulates Autophagy for Pulp Vitality in Glucose Oxidative Stress.

    Science.gov (United States)

    Lee, Y H; Kim, H S; Kim, J S; Yu, M K; Cho, S D; Jeon, J G; Yi, H K

    2016-04-01

    Diabetes mellitus is closely related to oral-complicated diseases by oxidative stress. This study investigates whether cellular myeloblastosis (c-myb) could protect human dental pulp cells against glucose oxidative stress and regulate autophagy activity for pulp vitality. Diabetes mellitus was induced by streptozotocin in Sprague-Dawley rats, and their pulp tissue in teeth was analyzed in terms of pulp cavity and molecules by hematoxylin and eosin and immunohistochemistry staining. Human dental pulp cells were serially subcultured and treated with glucose oxidase in the presence of elevated glucose to generate glucose oxidative stress. The replication-deficient adenovirus c-myb and small interfering RNA c-myb were introduced for c-myb expression. The pulp tissue from the diabetic rats was structurally different from normal tissue in terms of narrow pulp capacity, reduced c-myb, and dentinogenesis molecules. Glucose oxidase treatment decreased c-myb and dentinogenesis molecules (bone morphogenetic protein 2 and 7, dentin matrix protein 1, and dentin sialophosphoprotein) in human dental pulp cells. However, overexpression of c-myb by adenovirus c-myb increased dentinogenesis, autophagy molecules (autophagy protein 5, microtubule-associated protein 1A/1B-light chain 3, and Beclin-1), and cell survival via p-AMPK/AKT signaling even with glucose oxidative stress. In contrast, the lack of c-myb decreased the above molecules and cell survival by downregulating p-AMPK/AKT signaling. The results indicate that diabetes leads to irreversible damage to dental pulp, which is related to downexpression of autophagy via the p-AMPK/AKT pathway by decline of c-myb. The findings of this study provide a new insight that c-myb could ameliorate autophagy activity and that it is applicable for monitoring complicated diseases of dental pulp. The involvement of c-myb in pulp pathology could serve a therapeutic target in oral-complicated diseases.

  12. HSF-1 is involved in attenuating the release of inflammatory cytokines induced by LPS through regulating autophagy.

    Science.gov (United States)

    Tong, Zhongyi; Jiang, Bimei; Zhang, Lingli; Liu, Yanjuan; Gao, Min; Jiang, Yu; Li, Yuanbin; Lu, Qinglan; Yao, Yongming; Xiao, Xianzhong

    2014-05-01

    Autophagy plays a protective role in endotoxemic mice. Heat shock factor 1 (HSF-1) also plays a crucial protective role in endotoxemic mice by decreasing inflammatory cytokines. The purpose of this study was to determine whether HSF-1 is involved in attenuating the release of inflammatory cytokines in lipopolysaccharide (LPS)-stimulated mice and peritoneal macrophages (PMs) through regulating autophagy activity. Autophagosome formation in HSF-1(+/+) and HSF-1(-/-) mice and PMs stimulated by LPS was examined by Western blotting and immunofluorescence. Lipopolysaccharide-induced autophagy and inflammatory cytokines were examined in HSF-1(+/+) and HSF-1(-/-) PMs treated with 3-methyladenine (3-MA) or rapamycin. Results showed that LPS-induced autophagy was elevated transiently at 12 h but declined at 24 h in the livers and lungs of mice. Higher levels of inflammatory cytokines and lower autophagy activity were detected in HSF-1(-/-) mice and PMs compared with HSF-1(+/+) mice and PMs. Interestingly, LPS-induced release of inflammatory cytokines did not further increase in HSF-1(-/-) PMs treated with 3-MA but aggravated in HSF-1(+/+) PMs. Lipopolysaccharide-induced autophagy did not decrease in HSF-1(-/-) PMs treated with 3-MA but decreased in HSF-1 PMs(+/+). Taken together, our results suggested that HSF-1 attenuated the release of inflammatory cytokines induced by LPS by regulating autophagy activity.

  13. Effector caspase Dcp-1 and IAP protein Bruce regulate starvation-induced autophagy during Drosophila melanogaster oogenesis.

    Science.gov (United States)

    Hou, Ying-Chen Claire; Chittaranjan, Suganthi; Barbosa, Sharon González; McCall, Kimberly; Gorski, Sharon M

    2008-09-22

    A complex relationship exists between autophagy and apoptosis, but the regulatory mechanisms underlying their interactions are largely unknown. We conducted a systematic study of Drosophila melanogaster cell death-related genes to determine their requirement in the regulation of starvation-induced autophagy. We discovered that six cell death genes--death caspase-1 (Dcp-1), hid, Bruce, Buffy, debcl, and p53-as well as Ras-Raf-mitogen activated protein kinase signaling pathway components had a role in autophagy regulation in D. melanogaster cultured cells. During D. melanogaster oogenesis, we found that autophagy is induced at two nutrient status checkpoints: germarium and mid-oogenesis. At these two stages, the effector caspase Dcp-1 and the inhibitor of apoptosis protein Bruce function to regulate both autophagy and starvation-induced cell death. Mutations in Atg1 and Atg7 resulted in reduced DNA fragmentation in degenerating midstage egg chambers but did not appear to affect nuclear condensation, which indicates that autophagy contributes in part to cell death in the ovary. Our study provides new insights into the molecular mechanisms that coordinately regulate autophagic and apoptotic events in vivo. PMID:18794330

  14. Effector caspase Dcp-1 and IAP protein Bruce regulate starvation-induced autophagy during Drosophila melanogaster oogenesis.

    Science.gov (United States)

    Hou, Ying-Chen Claire; Chittaranjan, Suganthi; Barbosa, Sharon González; McCall, Kimberly; Gorski, Sharon M

    2008-09-22

    A complex relationship exists between autophagy and apoptosis, but the regulatory mechanisms underlying their interactions are largely unknown. We conducted a systematic study of Drosophila melanogaster cell death-related genes to determine their requirement in the regulation of starvation-induced autophagy. We discovered that six cell death genes--death caspase-1 (Dcp-1), hid, Bruce, Buffy, debcl, and p53-as well as Ras-Raf-mitogen activated protein kinase signaling pathway components had a role in autophagy regulation in D. melanogaster cultured cells. During D. melanogaster oogenesis, we found that autophagy is induced at two nutrient status checkpoints: germarium and mid-oogenesis. At these two stages, the effector caspase Dcp-1 and the inhibitor of apoptosis protein Bruce function to regulate both autophagy and starvation-induced cell death. Mutations in Atg1 and Atg7 resulted in reduced DNA fragmentation in degenerating midstage egg chambers but did not appear to affect nuclear condensation, which indicates that autophagy contributes in part to cell death in the ovary. Our study provides new insights into the molecular mechanisms that coordinately regulate autophagic and apoptotic events in vivo.

  15. Inducing autophagy

    DEFF Research Database (Denmark)

    Harder, Lea M; Bunkenborg, Jakob; Andersen, Jens S.

    2014-01-01

    Autophagy is a lysosomal-mediated catabolic process, which through degradation of different cytoplasmic components aids in maintaining cellular homeostasis and survival during exposure to extra- or intracellular stresses. Ammonia is a potential toxic and stress-inducing byproduct of glutamine...... catabolism, which has recently been found to induce autophagy in an MTOR independent way and support cancer cell survival. In this study, quantitative phosphoproteomics was applied to investigate the initial signaling events linking ammonia to the induction of autophagy. The MTOR inhibitor rapamycin was used...... as a reference treatment to emphasize the differences between an MTOR-dependent and -independent autophagy-induction. By this means 5901 phosphosites were identified of which 626 were treatment-specific regulated and 175 were coregulated. Investigation of the ammonia-specific regulated sites supported that MTOR...

  16. Leptin differentially regulate STAT3 activation in ob/ob mouse adipose mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    Zhou Zhou

    2012-12-01

    Full Text Available Abstract Background Leptin-deficient ob/ob mice exhibit adipocyte hypertrophy and hyperplasia as well as elevated adipose tissue and systemic inflammation. Multipotent stem cells isolated from adult adipose tissue can differentiate into adipocytes ex vivo and thereby contribute toward increased adipocyte cell numbers, obesity, and inflamm ation. Currently, information is lacking regarding regulation of adipose stem cell numbers as well as leptin-induced inflammation and its signaling pathway in ob/ob mice. Methods Using leptin deficient ob/ob mice, we investigated whether leptin injection into ob/ob mice increases adipose stem cell numbers and adipose tissue inflammatory marker MCP-1 mRNA and secretion levels. We also determined leptin mediated signaling pathways in the adipose stem cells. Results We report here that adipose stem cell number is significantly increased following leptin injection in ob/ob mice and with treatment of isolated stem cells with leptin in vitro. Leptin also up-regulated MCP-1 secretion in a dose- and time-dependent manner. We further showed that increased MCP-1 mRNA levels were due to increased phosphorylation of Signal Transducer and Activator of Transcription 3 (STAT3 Ser727 but not STAT3 Tyr705 phosphorylation, suggesting differential regulation of MCP-1 gene expression under basal and leptin-stimulated conditions in adipose stem cells. Conclusions Taken together, these studies demonstrate that leptin increases adipose stem cell number and differentially activates STAT3 protein resulting in up-regulation of MCP-1 gene expression. Further studies of mechanisms mediating adipose stem cell hyperplasia and leptin signaling in obesity are warranted and may help identify novel anti-obesity target strategies.

  17. Plac8 Links Oncogenic Mutations to Regulation of Autophagy and Is Critical to Pancreatic Cancer Progression

    Directory of Open Access Journals (Sweden)

    Conan Kinsey

    2014-05-01

    Full Text Available Mutations in p53 and RAS potently cooperate in oncogenic transformation, and correspondingly, these genetic alterations frequently coexist in pancreatic ductal adenocarcinoma (PDA and other human cancers. Previously, we identified a set of genes synergistically activated by combined RAS and p53 mutations as frequent downstream mediators of tumorigenesis. Here, we show that the synergistically activated gene Plac8 is critical for pancreatic cancer growth. Silencing of Plac8 in cell lines suppresses tumor formation by blocking autophagy, a process essential for maintaining metabolic homeostasis in PDA, and genetic inactivation in an engineered mouse model inhibits PDA progression. We show that Plac8 is a critical regulator of the autophagic machinery, localizing to the lysosomal compartment and facilitating lysosome-autophagosome fusion. Plac8 thus provides a mechanistic link between primary oncogenic mutations and the induction of autophagy, a central mechanism of metabolic reprogramming, during PDA progression.

  18. Effector caspase Dcp-1 and IAP protein Bruce regulate starvation-induced autophagy during Drosophila melanogaster oogenesis

    OpenAIRE

    Hou, Ying-Chen Claire; Chittaranjan, Suganthi; Barbosa, Sharon González; McCall, Kimberly; Gorski, Sharon M.

    2008-01-01

    A complex relationship exists between autophagy and apoptosis, but the regulatory mechanisms underlying their interactions are largely unknown. We conducted a systematic study of Drosophila melanogaster cell death–related genes to determine their requirement in the regulation of starvation-induced autophagy. We discovered that six cell death genes—death caspase-1 (Dcp-1), hid, Bruce, Buffy, debcl, and p53—as well as Ras–Raf–mitogen activated protein kinase signaling pathway components had a r...

  19. MARCH2 regulates autophagy by promoting CFTR ubiquitination and degradation and PIK3CA-AKT-MTOR signaling.

    Science.gov (United States)

    Xia, Dan; Qu, Liujing; Li, Ge; Hongdu, Beiqi; Xu, Chentong; Lin, Xin; Lou, Yaxin; He, Qihua; Ma, Dalong; Chen, Yingyu

    2016-09-01

    MARCH2 (membrane-associated RING-CH protein 2), an E3 ubiquitin ligase, is mainly associated with the vesicle trafficking. In the present study, for the first time, we demonstrated that MARCH2 negatively regulates autophagy. Our data indicated that overexpression of MARCH2 impaired autophagy, as evidenced by attenuated levels of LC3B-II and impaired degradation of endogenous and exogenous autophagic substrates. By contrast, loss of MARCH2 expression had the opposite effects. In vivo experiments demonstrate that MARCH2 knockout mediated autophagy results in an inhibition of tumorigenicity. Further investigation revealed that the induction of autophagy by MARCH2 deficiency was mediated through the PIK3CA-AKT-MTOR signaling pathway. Additionally, we found that MARCH2 interacts with CFTR (cystic fibrosis transmembrane conductance regulator), promotes the ubiquitination and degradation of CFTR, and inhibits CFTR-mediated autophagy in tumor cells. The functional PDZ domain of MARCH2 is required for the association with CFTR. Thus, our study identified a novel negative regulator of autophagy and suggested that the physical and functional connection between the MARCH2 and CFTR in different conditions will be elucidated in the further experiments. PMID:27308891

  20. Sirtuin 1 Regulates Dendritic Cell Activation and Autophagy during Respiratory Syncytial Virus-Induced Immune Responses.

    Science.gov (United States)

    Owczarczyk, Anna B; Schaller, Matthew A; Reed, Michelle; Rasky, Andrew J; Lombard, David B; Lukacs, Nicholas W

    2015-08-15

    Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infection in children worldwide. Sirtuin 1 (SIRT1), an NAD(+)-dependent deacetylase, has been associated with the induction of autophagy and the regulation of inflammatory mediators. We found that Sirt1 was upregulated in mouse lung after RSV infection. Infected animals that received EX-527, a selective SIRT1 inhibitor, displayed exacerbated lung pathology, with increased mucus production, elevated viral load, and enhanced Th2 cytokine production. Gene expression analysis of isolated cell populations revealed that Sirt1 was most highly upregulated in RSV-treated dendritic cells (DCs). Upon RSV infection, EX-527-treated DCs, Sirt1 small interfering RNA-treated DCs, or DCs from conditional knockout (Sirt1(f/f)-CD11c-Cre(+)) mice showed downregulated inflammatory cytokine gene expression and attenuated autophagy. Finally, RSV infection of Sirt1(f/f)-CD11c-Cre(+) mice resulted in altered lung and lymph node cytokine responses, leading to exacerbated pathology. These data indicate that SIRT1 promotes DC activation associated with autophagy-mediated processes during RSV infection, thereby directing efficient antiviral immune responses.

  1. Electroacupuncture Ameliorates Cerebral Ischemia-Reperfusion Injury by Regulation of Autophagy and Apoptosis

    Science.gov (United States)

    Shu, Shi; Li, Chun-Ming; You, Yan-Li; Qian, Xiao-Lu

    2016-01-01

    Background. The therapeutic mechanisms of cerebral ischemia treatment by acupuncture are yet not well addressed. Objective. We investigated the effects of electroacupuncture (EA) at GV26 observing the expression of autophagy-related proteins Beclin-1 and LC3B and proportion of apoptotic cells and Bcl-2 positive cells in MCAO/R model rats. Methods. Sprague-Dawley (SD) male rats were randomly assigned to 7 groups: model groups (M6h, M24h, and M72h), EA treatment groups (T6h, T24h, and T72h), and sham operation group (S). Neurological deficit and cerebral infarction volume were measured to assess the improvement effect, while the expression of Beclin-1 and LC3B and proportion of Tunel-positive and Bcl-2 positive cells were examined to explore EA effect on autophagy and apoptosis. Results. EA significantly decreased neurological deficit scores and the volume of cerebral infarction. Beclin-1 was significantly decreased in T24h, while LC3B-II/LC3B-I ratio markedly reduced in 6th hour. EA groups markedly reduced the number of Tunel positive cells, especially in T24h. Meanwhile, the number of Bcl-2 positive cells obviously increased after EA treatment, especially in T6h and T24h. Conclusions. The alleviation of inadequate autophagy and apoptosis may be a key mechanism involved in the reflex regulation of EA at GV26 to treat cerebral ischemia.

  2. SLAMF1 regulation of chemotaxis and autophagy determines CLL patient response

    Science.gov (United States)

    Bologna, Cinzia; Buonincontri, Roberta; Serra, Sara; Vaisitti, Tiziana; Audrito, Valentina; Brusa, Davide; Pagnani, Andrea; Coscia, Marta; D’Arena, Giovanni; Mereu, Elisabetta; Piva, Roberto; Furman, Richard R.; Rossi, Davide; Gaidano, Gianluca; Terhorst, Cox; Deaglio, Silvia

    2015-01-01

    Chronic lymphocytic leukemia (CLL) is a variable disease; therefore, markers to identify aggressive forms are essential for patient management. Here, we have shown that expression of the costimulatory molecule and microbial sensor SLAMF1 (also known as CD150) is lost in a subset of patients with an aggressive CLL that associates with a shorter time to first treatment and reduced overall survival. SLAMF1 silencing in CLL-like Mec-1 cells, which constitutively express SLAMF1, modulated pathways related to cell migration, cytoskeletal organization, and intracellular vesicle formation and recirculation. SLAMF1 deficiency associated with increased expression of CXCR4, CD38, and CD44, thereby positively affecting chemotactic responses to CXCL12. SLAMF1 ligation with an agonistic monoclonal antibody increased ROS accumulation and induced phosphorylation of p38, JNK1/2, and BCL2, thereby promoting the autophagic flux. Beclin1 dissociated from BCL2 in response to SLAMF1 ligation, resulting in formation of the autophagy macrocomplex, which contains SLAMF1, beclin1, and the enzyme VPS34. Accordingly, SLAMF1-silenced cells or SLAMF1lo primary CLL cells were resistant to autophagy-activating therapeutic agents, such as fludarabine and the BCL2 homology domain 3 mimetic ABT-737. Together, these results indicate that loss of SLAMF1 expression in CLL modulates genetic pathways that regulate chemotaxis and autophagy and that potentially affect drug responses, and suggest that these effects underlie unfavorable clinical outcome experienced by SLAMF1lo patients. PMID:26619119

  3. Hinokitiol protects primary neuron cells against prion peptide-induced toxicity via autophagy flux regulated by hypoxia inducing factor-1.

    Science.gov (United States)

    Moon, Ji-Hong; Lee, Ju-Hee; Lee, You-Jin; Park, Sang-Youel

    2016-05-24

    Prion diseases are fatal neurodegenerative disorders that are derived from structural changes of the native PrPc. Recent studies indicated that hinokitiol induced autophagy known to major function that keeps cells alive under stressful conditions. We investigated whether hinokitiol induces autophagy and attenuates PrP (106-126)-induced neurotoxicity. We observed increase of LC3-II protein level, GFP-LC3 puncta by hinokitiol in neuronal cells. Addition to, electron microscopy showed that hinokitiol enhanced autophagic vacuoles in neuronal cells. We demonstrated that hinokitiol protects against PrP (106-126)-induced neurotoxicity via autophagy by using autophagy inhibitor, wortmannin and 3MA, and ATG5 small interfering RNA (siRNA). We checked hinokitiol activated the hypoxia-inducible factor-1α (HIF-1α) and identified that hinokitiol-induced HIF-1α regulated autophagy. Taken together, this study is the first report demonstrating that hinokitiol protected against prion protein-induced neurotoxicity via autophagy regulated by HIF-1α. We suggest that hinokitiol is a possible therapeutic strategy in neuronal disorders including prion disease.

  4. A C9ORF72/SMCR8-containing complex regulates ULK1 and plays a dual role in autophagy

    Science.gov (United States)

    Yang, Mei; Liang, Chen; Swaminathan, Kunchithapadam; Herrlinger, Stephanie; Lai, Fan; Shiekhattar, Ramin; Chen, Jian-Fu

    2016-01-01

    The intronic GGGGCC hexanucleotide repeat expansion in chromosome 9 open reading frame 72 (C9ORF72) is a prevalent genetic abnormality identified in both frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Smith-Magenis syndrome chromosomal region candidate gene 8 (SMCR8) is a protein with unclear functions. We report that C9ORF72 is a component of a multiprotein complex containing SMCR8, WDR41, and ATG101 (an important regulator of autophagy). The C9ORF72 complex displays guanosine triphosphatase (GTPase) activity and acts as a guanosine diphosphate–guanosine 5′-triphosphate (GDP-GTP) exchange factor (GEF) for RAB39B. We created Smcr8 knockout mice and found that Smcr8 mutant cells exhibit impaired autophagy induction, which is similarly observed in C9orf72 knockdown cells. Mechanistically, SMCR8/C9ORF72 interacts with the key autophagy initiation ULK1 complex and regulates expression and activity of ULK1. The complex has an additional role in regulating later stages of autophagy. Whereas autophagic flux is enhanced in C9orf72 knockdown cells, depletion of Smcr8 results in a reduced flux with an abnormal expression of lysosomal enzymes. Thus, C9ORF72 and SMCR8 have similar functions in modulating autophagy induction by regulating ULK1 and play distinct roles in regulating autophagic flux. PMID:27617292

  5. Autophagy-related proteins are functionally active in human spermatozoa and may be involved in the regulation of cell survival and motility

    Science.gov (United States)

    Aparicio, I. M.; Espino, J.; Bejarano, I.; Gallardo-Soler, A.; Campo, M. L.; Salido, G. M.; Pariente, J. A.; Peña, F. J.; Tapia, J. A.

    2016-01-01

    Macroautophagy (hereafter autophagy) is an evolutionarily highly conserved cellular process that participates in the maintenance of intracellular homeostasis through the degradation of most long-lived proteins and entire organelles. Autophagy participates in some reproductive events; however, there are not reports regarding the role of autophagy in the regulation of sperm physiology. Hence, the aim of this study was to investigate whether autophagy-related proteins are present and functionally active in human spermatozoa. Proteins related to autophagy/mitophagy process (LC3, Atg5, Atg16, Beclin 1, p62, m-TOR, AMPKα 1/2, and PINK1) were present in human spermatozoa. LC3 colocalized with p62 in the middle piece of the spermatozoa. Autophagy activation induced a significant increase in motility and a decrease in PINK1, TOM20 expression and caspase 3/7 activation. In contrast, autophagy inhibition resulted in decreased motility, viability, ATP and intracellular calcium concentration whereas PINK1, TOM20 expression, AMPK phosphorylation and caspase 3/7 activation were significantly increased. In conclusion our results show that autophagy related proteins and upstream regulators are present and functional in human spermatozoa. Modification of mitochondrial proteins expression after autophagy activation/inhibition may be indicating that a specialized form of autophagy named mitophagy may be regulating sperm function such as motility and viability and may be cooperating with apoptosis. PMID:27633131

  6. Activation of ULK Kinase and Autophagy by GABARAP Trafficking from the Centrosome Is Regulated by WAC and GM130.

    Science.gov (United States)

    Joachim, Justin; Jefferies, Harold B J; Razi, Minoo; Frith, David; Snijders, Ambrosius P; Chakravarty, Probir; Judith, Delphine; Tooze, Sharon A

    2015-12-17

    Starvation-induced autophagy requires activation of the ULK complex at the phagophore. Two Golgi proteins, WAC and GM130, regulate autophagy, however their mechanism of regulation is unknown. In search of novel interaction partners of WAC, we found that GM130 directly interacts with WAC, and this interaction is required for autophagy. WAC is bound to the Golgi by GM130. WAC and GM130 interact with the Atg8 homolog GABARAP and regulate its subcellular localization. GABARAP is on the pericentriolar matrix, and this dynamic pool contributes to autophagosome formation. Tethering of GABARAP to the Golgi by GM130 inhibits autophagy, demonstrating an unexpected role for a golgin. WAC suppresses GM130 binding to GABARAP, regulating starvation-induced centrosomal GABARAP delivery to the phagophore. GABARAP, unlipidated and lipidated, but not LC3B, GABARAPL1, and GATE-16, specifically promotes ULK kinase activation dependent on the ULK1 LIR motif, elucidating a unique non-hierarchical role for GABARAP in starvation-induced activation of autophagy. PMID:26687599

  7. GADD45A inhibits autophagy by regulating the interaction between BECN1 and PIK3C3.

    Science.gov (United States)

    Zhang, Dongdong; Zhang, Weimin; Li, Dan; Fu, Ming; Chen, Runsheng; Zhan, Qimin

    2015-01-01

    GADD45A is a TP53-regulated and DNA damage-inducible tumor suppressor protein, which regulates cell cycle arrest, apoptosis, and DNA repair, and inhibits tumor growth and angiogenesis. However, the function of GADD45A in autophagy remains unknown. In this report, we demonstrate that GADD45A plays an important role in regulating the process of autophagy. GADD45A is able to decrease LC3-II expression and numbers of autophagosomes in mouse tissues and different cancer cell lines. Using bafilomycin A1 treatment, we have observed that GADD45A regulates autophagosome initiation. Likely, GADD45A inhibition of autophagy is through its influence on the interaction between BECN1 and PIK3C3. Immunoprecipitation and GST affinity isolation assays exhibit that GADD45A directly interacts with BECN1, and in turn dissociates the BECN1-PIK3C3 complex. Furthermore, we have mapped the 71 to 81 amino acids of the GADD45A protein that are necessary for the GADD45A interaction with BECN1. Knockdown of BECN1 can abolish autophagy alterations induced by GADD45A. Taken together, these findings provide the novel evidence that GADD45A inhibits autophagy via impairing the BECN1-PIK3C3 complex formation.

  8. Impaired macrophage autophagy increases the immune response in obese mice by promoting proinflammatory macrophage polarization.

    Science.gov (United States)

    Liu, Kun; Zhao, Enpeng; Ilyas, Ghulam; Lalazar, Gadi; Lin, Yu; Haseeb, Muhammad; Tanaka, Kathryn E; Czaja, Mark J

    2015-01-01

    Recent evidence that excessive lipid accumulation can decrease cellular levels of autophagy and that autophagy regulates immune responsiveness suggested that impaired macrophage autophagy may promote the increased innate immune activation that underlies obesity. Primary bone marrow-derived macrophages (BMDM) and peritoneal macrophages from high-fat diet (HFD)-fed mice had decreased levels of autophagic flux indicating a generalized impairment of macrophage autophagy in obese mice. To assess the effects of decreased macrophage autophagy on inflammation, mice with a Lyz2-Cre-mediated knockout of Atg5 in macrophages were fed a HFD and treated with low-dose lipopolysaccharide (LPS). Knockout mice developed systemic and hepatic inflammation with HFD feeding and LPS. This effect was liver specific as knockout mice did not have increased adipose tissue inflammation. The mechanism by which the loss of autophagy promoted inflammation was through the regulation of macrophage polarization. BMDM and Kupffer cells from knockout mice exhibited abnormalities in polarization with both increased proinflammatory M1 and decreased anti-inflammatory M2 polarization as determined by measures of genes and proteins. The heightened hepatic inflammatory response in HFD-fed, LPS-treated knockout mice led to liver injury without affecting steatosis. These findings demonstrate that autophagy has a critical regulatory function in macrophage polarization that downregulates inflammation. Defects in macrophage autophagy may underlie inflammatory disease states such as the decrease in macrophage autophagy with obesity that leads to hepatic inflammation and the progression to liver injury.

  9. IL-6 regulates exercise and training-induced adaptations in subcutaneous adipose tissue in mice

    DEFF Research Database (Denmark)

    Brandt, Claus; Jakobsen, Anne Hviid; Hassing, Helle Adser;

    2012-01-01

    Aim: The aim of this study was to test the hypothesis that IL-6 regulates exercise-induced gene responses in subcutaneous adipose tissue in mice. Methods: Four months old male IL-6 whole body knockout (KO) mice and C57B wild-type (WT) mice performed 1h of treadmill exercise, where subcutaneous...... adipose tissue (AT) was removed either immediately after, 4h or 10h after exercise as well as from mice not running acutely. Moreover, AT was sampled at resting conditions after 5 weeks of exercise training. Results: AT leptin mRNA decreased immediately after a single running exercise bout in both...... in regulating exercise and training-induced leptin and PPAR¿ expression in adipose tissue. In addition, while IL-6 is required for TNF-a mRNA reduction in response to acute exercise, IL-6 does not appear to be mandatory for anti-inflammatory effects of exercise training in adipose tissue....

  10. Galectin-4 expression is down-regulated in response to autophagy during differentiation of rat trophoblast cells.

    Science.gov (United States)

    Arikawa, Tomohiro; Liao, Shengjun; Shimada, Hiroki; Inoue, Tomoki; Sakata-Haga, Hiromi; Nakamura, Takanori; Hatta, Toshihisa; Shoji, Hiroki

    2016-01-01

    Placental development and trophoblast invasion of the maternal endometrium establish the maternal-fetal interface, which is critical for the developing embryo and fetus. Herein we show that overexpression of Galectin-4 (Gal-4) during trophoblast differentiation inhibited the enlargement of Rcho-1 cells (a model for rat trophoblast differentiation) and promoted cell-cell adhesion, whereas trophoblast specific markers and MMP-9 activity were not affected. In the rat placenta, microtubule associated protein 1 light chain 3 alpha (LC3) protein, an autophagy marker, is highly expressed on the maternal side of the decidua where Gal-4 expression is weak. In vitro assays showed that the expression of trophoblast-specific differentiation markers was reduced by 3-Methyladenine (3-MA) and Bafilomycin A1, known as autophagy inhibitors, compared to control cells. Furthermore, Gal-4 expression in Rcho-1 cells, which is normally down-regulated during differentiation, was not attenuated in the presence of autophagy inhibitors, suggesting that autophagy is upstream of Gal-4 expression. We herein describe a possible mechanism by which autophagy regulates trophoblast differentiation via regulation of Gal-4 expression in order to establish the maternal-fetal interface. PMID:27572741

  11. Ghrelin receptor regulates adipose tissue inflammation in aging

    Science.gov (United States)

    Aging is commonly associated with low-grade adipose inflammation, which is closely linked to insulin resistance. Ghrelin is the only circulating orexigenic hormone which is known to increase obesity and insulin resistance. We previously reported that the expression of the ghrelin receptor, growth ho...

  12. Hormonal regulation of lipoprotein lipase in adipose tissue (studies in the rat and in humans)

    NARCIS (Netherlands)

    M.G.A. Baggen (Marinus)

    1988-01-01

    textabstractCurrent data strongly suggest the most important role for insulin in the hormonal regulation of adipose tissue LPL activity. It is not clear from the literature what the role is of glucocorticoids in the regulation of the enzyme. Stress hormones as ACTH and adrenalin for example seem to

  13. Doxorubicin Regulates Autophagy Signals via Accumulation of Cytosolic Ca2+ in Human Cardiac Progenitor Cells

    Science.gov (United States)

    Park, Ji Hye; Choi, Sung Hyun; Kim, Hyungtae; Ji, Seung Taek; Jang, Woong Bi; Kim, Jae Ho; Baek, Sang Hong; Kwon, Sang Mo

    2016-01-01

    Doxorubicin (DOXO) is widely used to treat solid tumors. However, its clinical use is limited by side effects including serious cardiotoxicity due to cardiomyocyte damage. Resident cardiac progenitor cells (hCPCs) act as key regulators of homeostasis in myocardial cells. However, little is known about the function of hCPCs in DOXO-induced cardiotoxicity. In this study, we found that DOXO-mediated hCPC toxicity is closely related to calcium-related autophagy signaling and was significantly attenuated by blocking mTOR signaling in human hCPCs. DOXO induced hCPC apoptosis with reduction of SMP30 (regucalcin) and autophagosome marker LC3, as well as remarkable induction of the autophagy-related markers, Beclin-1, APG7, and P62/SQSTM1 and induction of calcium-related molecules, CaM (Calmodulin) and CaMKII (Calmodulin kinase II). The results of an LC3 puncta assay further indicated that DOXO reduced autophagosome formation via accumulation of cytosolic Ca2+. Additionally, DOXO significantly induced mTOR expression in hCPCs, and inhibition of mTOR signaling by rapamycin, a specific inhibitor, rescued DOXO-mediated autophagosome depletion in hCPCs with significant reduction of DOXO-mediated cytosolic Ca2+ accumulation in hCPCs, and restored SMP30 and mTOR expression. Thus, DOXO-mediated hCPC toxicity is linked to Ca2+-related autophagy signaling, and inhibition of mTOR signaling may provide a cardio-protective effect against DOXO-mediated hCPC toxicity. PMID:27735842

  14. Oxygen-glucose deprivation regulates BACE1 expression through induction of autophagy in Neuro-2a/APP695 cells

    Institute of Scientific and Technical Information of China (English)

    Rong-fu Chen; Xiao-jiang Sun; Ting Zhang; Yin-yi Sun; Ya-meng Sun; Wen-qi Chen; Nan Shi; Fang Shen; Yan Zhang; Kang-yong Liu

    2015-01-01

    Our previous ifndings have demonstrated that autophagy regulation can alleviate the decline of learning and memory by eliminating deposition of extracellular beta-amyloid peptide (Aβ) in the brain after stroke, but the exact mechanism is unclear. It is presumed that the regulation of beta-site APP-cleaving enzyme 1 (BACE1), the rate-limiting enzyme in metabolism of Aβ, would be a key site. Neuro-2a/amyloid precursor protein 695 (APP695) cell models of cerebral isch-emia were established by oxygen-glucose deprivation to investigate the effects of Rapamycin (an autophagy inducer) or 3-methyladenine (an autophagy inhibitor) on the expression of BACE1. Either oxygen-glucose deprivation or Rapamycin down-regulated the expression of BACE1 while 3-methyladenine up-regulated BACE1 expression. These results confirm that oxygen-glucose deprivation down-regulates BACE1 expression in Neuro-2a/APP695 cells through the introduc-tion of autophagy.

  15. Oxygen-glucose deprivation regulates BACE1 expression through induction of autophagy in Neuro-2a/APP695 cells

    Directory of Open Access Journals (Sweden)

    Rong-fu Chen

    2015-01-01

    Full Text Available Our previous findings have demonstrated that autophagy regulation can alleviate the decline of learning and memory by eliminating deposition of extracellular beta-amyloid peptide (Aβ in the brain after stroke, but the exact mechanism is unclear. It is presumed that the regulation of beta-site APP-cleaving enzyme 1 (BACE1, the rate-limiting enzyme in metabolism of Aβ, would be a key site. Neuro-2a/amyloid precursor protein 695 (APP695 cell models of cerebral ischemia were established by oxygen-glucose deprivation to investigate the effects of Rapamycin (an autophagy inducer or 3-methyladenine (an autophagy inhibitor on the expression of BACE1. Either oxygen-glucose deprivation or Rapamycin down-regulated the expression of BACE1 while 3-methyladenine up-regulated BACE1 expression. These results confirm that oxygen-glucose deprivation down-regulates BACE1 expression in Neuro-2a/APP695 cells through the introduction of autophagy.

  16. TOR complex 2-Ypk1 signaling is an essential positive regulator of the general amino acid control response and autophagy.

    Science.gov (United States)

    Vlahakis, Ariadne; Graef, Martin; Nunnari, Jodi; Powers, Ted

    2014-07-22

    The highly conserved Target of Rapamycin (TOR) kinase is a central regulator of cell growth and metabolism in response to nutrient availability. TOR functions in two structurally and functionally distinct complexes, TOR Complex 1 (TORC1) and TOR Complex 2 (TORC2). Through TORC1, TOR negatively regulates autophagy, a conserved process that functions in quality control and cellular homeostasis and, in this capacity, is part of an adaptive nutrient deprivation response. Here we demonstrate that during amino acid starvation TOR also operates independently as a positive regulator of autophagy through the conserved TORC2 and its downstream target protein kinase, Ypk1. Under these conditions, TORC2-Ypk1 signaling negatively regulates the Ca(2+)/calmodulin-dependent phosphatase, calcineurin, to enable the activation of the amino acid-sensing eIF2α kinase, Gcn2, and to promote autophagy. Our work reveals that the TORC2 pathway regulates autophagy in an opposing manner to TORC1 to provide a tunable response to cellular metabolic status.

  17. Leucine Supplementation Protects from Insulin Resistance by Regulating Adiposity Levels

    Science.gov (United States)

    Binder, Elke; Bermúdez-Silva, Francisco J.; André, Caroline; Elie, Melissa; Romero-Zerbo, Silvana Y.; Leste-Lasserre, Thierry; Belluomo, llaria; Duchampt, Adeline; Clark, Samantha; Aubert, Agnes; Mezzullo, Marco; Fanelli, Flaminia; Pagotto, Uberto; Layé, Sophie; Mithieux, Gilles; Cota, Daniela

    2013-01-01

    Background Leucine supplementation might have therapeutic potential in preventing diet-induced obesity and improving insulin sensitivity. However, the underlying mechanisms are at present unclear. Additionally, it is unclear whether leucine supplementation might be equally efficacious once obesity has developed. Methodology/Principal Findings Male C57BL/6J mice were fed chow or a high-fat diet (HFD), supplemented or not with leucine for 17 weeks. Another group of HFD-fed mice (HFD-pairfat group) was food restricted in order to reach an adiposity level comparable to that of HFD-Leu mice. Finally, a third group of mice was exposed to HFD for 12 weeks before being chronically supplemented with leucine. Leucine supplementation in HFD-fed mice decreased body weight and fat mass by increasing energy expenditure, fatty acid oxidation and locomotor activity in vivo. The decreased adiposity in HFD-Leu mice was associated with increased expression of uncoupling protein 3 (UCP-3) in the brown adipose tissue, better insulin sensitivity, increased intestinal gluconeogenesis and preservation of islets of Langerhans histomorphology and function. HFD-pairfat mice had a comparable improvement in insulin sensitivity, without changes in islets physiology or intestinal gluconeogenesis. Remarkably, both HFD-Leu and HFD-pairfat mice had decreased hepatic lipid content, which likely helped improve insulin sensitivity. In contrast, when leucine was supplemented to already obese animals, no changes in body weight, body composition or glucose metabolism were observed. Conclusions/Significance These findings suggest that leucine improves insulin sensitivity in HFD-fed mice by primarily decreasing adiposity, rather than directly acting on peripheral target organs. However, beneficial effects of leucine on intestinal gluconeogenesis and islets of Langerhans's physiology might help prevent type 2 diabetes development. Differently, metabolic benefit of leucine supplementation is lacking in

  18. Leucine supplementation protects from insulin resistance by regulating adiposity levels.

    Directory of Open Access Journals (Sweden)

    Elke Binder

    Full Text Available BACKGROUND: Leucine supplementation might have therapeutic potential in preventing diet-induced obesity and improving insulin sensitivity. However, the underlying mechanisms are at present unclear. Additionally, it is unclear whether leucine supplementation might be equally efficacious once obesity has developed. METHODOLOGY/PRINCIPAL FINDINGS: Male C57BL/6J mice were fed chow or a high-fat diet (HFD, supplemented or not with leucine for 17 weeks. Another group of HFD-fed mice (HFD-pairfat group was food restricted in order to reach an adiposity level comparable to that of HFD-Leu mice. Finally, a third group of mice was exposed to HFD for 12 weeks before being chronically supplemented with leucine. Leucine supplementation in HFD-fed mice decreased body weight and fat mass by increasing energy expenditure, fatty acid oxidation and locomotor activity in vivo. The decreased adiposity in HFD-Leu mice was associated with increased expression of uncoupling protein 3 (UCP-3 in the brown adipose tissue, better insulin sensitivity, increased intestinal gluconeogenesis and preservation of islets of Langerhans histomorphology and function. HFD-pairfat mice had a comparable improvement in insulin sensitivity, without changes in islets physiology or intestinal gluconeogenesis. Remarkably, both HFD-Leu and HFD-pairfat mice had decreased hepatic lipid content, which likely helped improve insulin sensitivity. In contrast, when leucine was supplemented to already obese animals, no changes in body weight, body composition or glucose metabolism were observed. CONCLUSIONS/SIGNIFICANCE: These findings suggest that leucine improves insulin sensitivity in HFD-fed mice by primarily decreasing adiposity, rather than directly acting on peripheral target organs. However, beneficial effects of leucine on intestinal gluconeogenesis and islets of Langerhans's physiology might help prevent type 2 diabetes development. Differently, metabolic benefit of leucine supplementation

  19. Insulin Regulates the Unfolded Protein Response in Human Adipose Tissue

    OpenAIRE

    Boden, Guenther; Cheung, Peter; Salehi, Sajad; Homko, Carol; Loveland-Jones, Catherine; Jayarajan, Senthil; Stein, T Peter; Williams, Kevin Jon; Liu, Ming-Lin; Barrero, Carlos A.; Merali, Salim

    2014-01-01

    Endoplasmic reticulum (ER) stress is increased in obesity and is postulated to be a major contributor to many obesity-related pathologies. Little is known about what causes ER stress in obese people. Here, we show that insulin upregulated the unfolded protein response (UPR), an adaptive reaction to ER stress, in vitro in 3T3-L1 adipocytes and in vivo, in subcutaneous (sc) adipose tissue of nondiabetic subjects, where it increased the UPR dose dependently over the entire physiologic insulin ra...

  20. Regulation of protein synthesis and autophagy in activated dendritic cells: implications for antigen processing and presentation.

    Science.gov (United States)

    Argüello, Rafael J; Reverendo, Marisa; Gatti, Evelina; Pierre, Philippe

    2016-07-01

    Antigenic peptides presented in the context of major histocompatibility complex (MHC) molecules originate from the degradation of both self and non-self proteins. T cells can therefore recognize at the surface of surveyed cells, the self-peptidome produced by the cell itself (mostly inducing tolerance) or immunogenic peptides derived from exogenous origins. The initiation of adaptive immune responses by dendritic cells (DCs), through the antigenic priming of naïve T cells, is associated to microbial pattern recognition receptors engagement. Activation of DCs by microbial product or inflammatory cytokines initiates multiple processes that maximize DC capacity to present exogenous antigens and stimulate T cells by affecting major metabolic and membrane traffic pathways. These include the modulation of protein synthesis, the regulation of MHC and co-stimulatory molecules transport, as well as the regulation of autophagy, that, all together promote exogenous antigen presentation while limiting the display of self-antigens by MHC molecules.

  1. TORC1 Inhibits GSK3-Mediated Elo2 Phosphorylation to Regulate Very Long Chain Fatty Acid Synthesis and Autophagy

    Directory of Open Access Journals (Sweden)

    Christine Zimmermann

    2013-11-01

    Full Text Available Very long chain fatty acids (VLCFAs are essential fatty acids with multiple functions, including ceramide synthesis. Although the components of the VLCFA biosynthetic machinery have been elucidated, how their activity is regulated to meet the cell’s metabolic demand remains unknown. The goal of this study was to identify mechanisms that regulate the rate of VLCFA synthesis, and we discovered that the fatty acid elongase Elo2 is regulated by phosphorylation. Elo2 phosphorylation is induced upon inhibition of TORC1 and requires GSK3. Expression of nonphosphorylatable Elo2 profoundly alters the ceramide spectrum, reflecting aberrant VLCFA synthesis. Furthermore, VLCFA depletion results in constitutive activation of autophagy, which requires sphingoid base phosphorylation. This constitutive activation of autophagy diminishes cell survival, indicating that VLCFAs serve to dampen the amplitude of autophagy. Together, our data reveal a function for TORC1 and GSK3 in the regulation of VLCFA synthesis that has important implications for autophagy and cell homeostasis.

  2. Roles and regulation of autophagy and apoptosis in the remodelling of the lepidopteran midgut epithelium during metamorphosis

    Science.gov (United States)

    Romanelli, Davide; Casartelli, Morena; Cappellozza, Silvia; de Eguileor, Magda; Tettamanti, Gianluca

    2016-01-01

    We previously showed that autophagy and apoptosis occur in the removal of the lepidopteran larval midgut during metamorphosis. However, their roles in this context and the molecular pathways underlying their activation and regulation were only hypothesized. The results of the present study better clarify the timing of the activation of these two processes: autophagic and apoptotic genes are transcribed at the beginning of metamorphosis, but apoptosis intervenes after autophagy. To investigate the mechanisms that promote the activation of autophagy and apoptosis, we designed a set of experiments based on injections of 20-hydroxyecdysone (20E). Our data demonstrate that autophagy is induced at the end of the last larval stage by the 20E commitment peak, while the onset of apoptosis occurs concomitantly with the 20E metamorphic peak. By impairing autophagic flux, the midgut epithelium degenerated faster, and higher caspase activity was observed compared to controls, whereas inhibiting caspase activation caused a severe delay in epithelial degeneration. Our data demonstrate that autophagy plays a pro-survival function in the silkworm midgut during metamorphosis, while apoptosis is the major process that drives the demise of the epithelium. The evidence collected in this study seems to exclude the occurrence of autophagic cell death in this setting. PMID:27609527

  3. Roles and regulation of autophagy and apoptosis in the remodelling of the lepidopteran midgut epithelium during metamorphosis

    Science.gov (United States)

    Romanelli, Davide; Casartelli, Morena; Cappellozza, Silvia; de Eguileor, Magda; Tettamanti, Gianluca

    2016-09-01

    We previously showed that autophagy and apoptosis occur in the removal of the lepidopteran larval midgut during metamorphosis. However, their roles in this context and the molecular pathways underlying their activation and regulation were only hypothesized. The results of the present study better clarify the timing of the activation of these two processes: autophagic and apoptotic genes are transcribed at the beginning of metamorphosis, but apoptosis intervenes after autophagy. To investigate the mechanisms that promote the activation of autophagy and apoptosis, we designed a set of experiments based on injections of 20-hydroxyecdysone (20E). Our data demonstrate that autophagy is induced at the end of the last larval stage by the 20E commitment peak, while the onset of apoptosis occurs concomitantly with the 20E metamorphic peak. By impairing autophagic flux, the midgut epithelium degenerated faster, and higher caspase activity was observed compared to controls, whereas inhibiting caspase activation caused a severe delay in epithelial degeneration. Our data demonstrate that autophagy plays a pro-survival function in the silkworm midgut during metamorphosis, while apoptosis is the major process that drives the demise of the epithelium. The evidence collected in this study seems to exclude the occurrence of autophagic cell death in this setting.

  4. Dissecting adipose tissue lipolysis: molecular regulation and implications for metabolic disease

    DEFF Research Database (Denmark)

    Nielsen, Thomas Svava; Jessen, Niels; Jørgensen, Jens Otto Lunde;

    2014-01-01

    is tightly regulated by hormonal and nutritional factors. Under conditions of negative energy balance such as fasting and exercise, stimulation of lipolysis results in a profound increase in FFA release from adipose tissue. This response is crucial in order to provide the organism with a sufficient supply...... localization, protein-protein interactions, and protein stability/degradation. Here, we provide an overview of the recent advances in the field of adipose tissue lipolysis with particular focus on the molecular regulation of the two main lipases, ATGL and HSL and the intracellular and extracellular signals......Lipolysis is the process by which triglycerides are hydrolyzed to free fatty acids (FFA) and glycerol. In adipocytes, this is achieved by the sequential action of Adipose Triglyceride Lipase (ATGL), Hormone Sensitive Lipase (HSL) and Monoglyceride Lipase (MGL). The activity in the lipolytic pathway...

  5. b-Series gangliosides crucially regulate leptin secretion in adipose tissues.

    Science.gov (United States)

    Ji, Shuting; Ohkawa, Yuki; Tokizane, Kyohei; Ohmi, Yuhsuke; Banno, Ryoichi; Furukawa, Keiko; Kiyama, Hiroshi; Furukawa, Koichi

    2015-04-01

    Gangliosides are widely involved in the regulation of cells and organs. However, little is known about their roles in leptin secretion from adipose tissues. Genetic deletion of b-series gangliosides resulted in the marked reduction of serum leptin. Expression analysis of leptin revealed that leptin accumulated in the adipose tissues of GD3 synthase-knockout (GD3S KO) mice. Analysis of primary cultured stromal vascular fractions (SVF) derived from GD3S KO mice revealed that leptin secretion was reduced, although leptin amounts in cells were increased compared with those of wild type. Interestingly, addition of b-series gangliosides to the culture medium of differentiated SVF resulted in the restoration of leptin secretion. Results of methyl-β-cyclodextrin treatment of differentiated 3T3-L1 cells as well as immunocytostaining of leptin and caveolin-1 suggested that b-series gangliosides regulate the leptin secretion from adipose tissues in lipid rafts.

  6. Autophagy counteracts apoptosis in human multiple myeloma cells exposed to oridonin in vitro via regulating intracellular ROS and SIRT1

    Institute of Scientific and Technical Information of China (English)

    Rong ZENG; Yan CHEN; Shuai ZHAO; Guo-hui CUI

    2012-01-01

    To explore the mechanisms underlying the oridonin-induced apoptosis and autophagy in human multiple myeloma cells in vitro.Methods:Human multiple myeloma RPMI8266 cells were used.The cell viability was assessed using MTT assay.Morphological changes of apoptosis and autophagy were observed under transmission electron microscope.TUNEL and annexin V-FITC/PI dual staining assays were used to measure apoptosis.Autophagy was analyzed using Western blot analysis and immunofluorescence staining with a QDs605 nm-Anti-LC3 fluorescent probe.Intracellular ROS was estimated with flow cytometry using DCFH-DA fluorescent probe.Protein levels of active caspase 3,Beclin 1 and SIRT1 were determined with Western blot analysis.Results:Exposure to oridonin (1-64 μmol/L) inhibited the proliferation of RPMI8266 cells in a concentration-dependent manner with an IC50 value of 6.74 μmol/L.Exposure to oridonin (7 μmol/L) simultaneously induced caspase 3-mediated apoptosis and Beclin 1-dependent autophagy of RPMI8266 cells.Both the apoptosis and autophagy were time-dependent,and apoptosis was the main effector pathway of cell death.Exposure to oridonin (7 μmol/L) increased intracellular ROS and reduced SIRT1 nuclear protein in a time-dependent manner.The blockade of intracellular generation of ROS by NAC (5 mmol/L) abrogated apoptosis,autophagy and the decrease of SIRT1 in the cells exposed to oridonin (7 μmol/L).The inhibition of autophagy by 3-MA (5 mmol/L) sensitized the cells to oridonin-induced apoptosis,which was accompanied by increased intracellular ROS and decreased SlRT1.Conclusion:Oridonin simultaneously induces apoptosis and autophagy of human multiple myeloma RPMI8266 cells via regulation of intracellular ROS generation and SIRT1 nuclear protein.The cytotoxicity of oridonin is mainly mediated through the apoptotic pathway,whereas the autophagy protects the cells from apoptosis.

  7. Up-Regulation of Mitochondrial Activity and Acquirement of Brown Adipose Tissue-Like Property in the White Adipose Tissue of Fsp27 Deficient Mice

    OpenAIRE

    Toh, Shen Yon; Gong, Jingyi; Du, Guoli; Li, John Zhong; Yang, Shuqun; Ye, Jing; Yao, Huilan; Zhang, Yinxin; Xue, Bofu; Li, Qing; Yang, Hongyuan; Wen, Zilong; Li, Peng

    2008-01-01

    Fsp27, a member of the Cide family proteins, was shown to localize to lipid droplet and promote lipid storage in adipocytes. We aimed to understand the biological role of Fsp27 in regulating adipose tissue differentiation, insulin sensitivity and energy balance. Fsp27 −/− mice and Fsp27/lep double deficient mice were generated and we examined the adiposity, whole body metabolism, BAT and WAT morphology, insulin sensitivity, mitochondrial activity, and gene expression changes in these mouse st...

  8. Up-Regulation of Mitochondrial Activity and Acquirement of Brown Adipose Tissue-Like Property in the White Adipose Tissue of Fsp27 Deficient Mice

    OpenAIRE

    Shen Yon Toh; Jingyi Gong; Guoli Du; John Zhong Li; Shuqun Yang; Jing Ye; Huilan Yao; Yinxin Zhang; Bofu Xue; Qing Li; Hongyuan Yang; Zilong Wen; Peng Li

    2008-01-01

    Fsp27, a member of the Cide family proteins, was shown to localize to lipid droplet and promote lipid storage in adipocytes. We aimed to understand the biological role of Fsp27 in regulating adipose tissue differentiation, insulin sensitivity and energy balance. Fsp27(-/-) mice and Fsp27/lep double deficient mice were generated and we examined the adiposity, whole body metabolism, BAT and WAT morphology, insulin sensitivity, mitochondrial activity, and gene expression changes in these mouse s...

  9. GAIP interacting protein C-terminus regulates autophagy and exosome biogenesis of pancreatic cancer through metabolic pathways.

    Directory of Open Access Journals (Sweden)

    Santanu Bhattacharya

    Full Text Available GAIP interacting protein C terminus (GIPC is known to play an important role in a variety of physiological and disease states. In the present study, we have identified a novel role for GIPC as a master regulator of autophagy and the exocytotic pathways in cancer. We show that depletion of GIPC-induced autophagy in pancreatic cancer cells, as evident from the upregulation of the autophagy marker LC3II. We further report that GIPC regulates cellular trafficking pathways by modulating the secretion, biogenesis, and molecular composition of exosomes. We also identified the involvement of GIPC on metabolic stress pathways regulating autophagy and microvesicular shedding, and observed that GIPC status determines the loading of cellular cargo in the exosome. Furthermore, we have shown the overexpression of the drug resistance gene ABCG2 in exosomes from GIPC-depleted pancreatic cancer cells. We also demonstrated that depletion of GIPC from cancer cells sensitized them to gemcitabine treatment, an avenue that can be explored as a potential therapeutic strategy to overcome drug resistance in cancer.

  10. Adipose Genes Down-Regulated During Experimental Endotoxemia Are Also Suppressed in Obesity

    Science.gov (United States)

    Hinkle, Christine C.; Haris, Lalarukh; Shah, Rhia; Mehta, Nehal N.; Putt, Mary E.; Reilly, Muredach P.

    2012-01-01

    Context: Adipose inflammation is a crucial link between obesity and its metabolic complications. Human experimental endotoxemia is a controlled model for the study of inflammatory cardiometabolic responses in vivo. Objective: We hypothesized that adipose genes down-regulated during endotoxemia would approximate changes observed with obesity-related inflammation and reveal novel candidates in cardiometabolic disease. Design, Subjects, and Intervention: Healthy volunteers (n = 14) underwent a 3 ng/kg endotoxin challenge; adipose biopsies were taken at 0, 4, 12, and 24 h for mRNA microarray. A priority list of highly down-regulated and biologically relevant genes was validated by RT-PCR in an independent sample of adipose from healthy subjects (n = 7) undergoing a subclinical 0.6 ng/kg endotoxemia protocol. Expression of validated genes was screened in adipose of lean and severely obese individuals (n = 11 per group), and cellular source was probed in cultured adipocytes and macrophages. Results: Endotoxemia (3 ng/kg) suppressed expression of 353 genes (to <67% of baseline; P < 1 × 10−5) of which 68 candidates were prioritized for validation. In low-dose (0.6 ng/kg) endotoxin validation, 22 (32%) of these 68 genes were confirmed. Functional classification revealed that many of these genes are involved in cell development and differentiation. Of validated genes, 59% (13 of 22) were down-regulated more than 1.5-fold in primary human adipocytes after treatment with endotoxin. In human macrophages, 59% (13 of 22) were up-regulated during differentiation to inflammatory M1 macrophages whereas 64% (14 of 22) were down-regulated during transition to homeostatic M2 macrophages. Finally, in obese vs. lean adipose, 91% (20 of 22) tended to have reduced expression (χ2 = 10.72, P < 0.01) with 50% (11 of 22) reaching P < 0.05 (χ2 = 9.28, P < 0.01). Conclusions: Exploration of down-regulated mRNA in adipose during human endotoxemia revealed suppression of genes involved in

  11. β-Adrenergic agonist and antagonist regulation of autophagy in HepG2 cells, primary mouse hepatocytes, and mouse liver.

    Directory of Open Access Journals (Sweden)

    Benjamin L Farah

    Full Text Available Autophagy recently has been shown to be involved in normal hepatic function and in pathological conditions such as non-alcoholic fatty liver disease. Adrenergic signalling also is an important regulator of hepatic metabolism and function. However, currently little is known about the potential role of adrenergic signaling on hepatic autophagy, and whether the β-adrenergic receptor itself may be a key regulator of autophagy. To address these issues, we investigated the actions of the β2-adrenergic receptor agonist, clenbuterol on hepatic autophagy. Surprisingly, we found that clenbuterol stimulated autophagy and autophagic flux in hepatoma cells, primary hepatocytes and in vivo. Similar effects also were observed with epinephrine treatment. Interestingly, propranolol caused a late block in autophagy in the absence and presence of clenbuterol, both in cell culture and in vivo. Thus, our results demonstrate that the β2-adrenergic receptor is a key regulator of hepatic autophagy, and that the β-blocker propranolol can independently induce a late block in autophagy.

  12. Autophagy Regulates the Post-Translational Cleavage of BCL-2 and Promotes Neuronal Survival

    Directory of Open Access Journals (Sweden)

    Laura Lossi

    2010-01-01

    Full Text Available B-cell lymphoma 2 protein (BCL-2 is one of the more widely investigated anti-apoptotic protein in mammals, and its levels are critical for protecting from programmed cell death. We report here that the cellular content of BCL-2 is regulated at post-translational level along the autophagy/lysosome pathways in organotypic cultures of post-natal mouse cerebellar cortex. Specifically this mechanism appears to be effective in the cerebellar granule cells (CGCs that are known to undergo massive programmed cell death (apoptosis during post-natal maturation. By the use of specific agonists/antagonist of calcium channels at the endoplasmic reticulum it was possible to understand the pivotal role of calcium release from intracellular stores in CGC neuroprotection. The more general significance of these findings is supported by a very recent study Niemann-Pick transgenic mice.

  13. Effect of regional muscle location but not adiposity on mitochondrial biogenesis-regulating proteins

    DEFF Research Database (Denmark)

    Ponce-González, Jesús Gustavo; Ara, Ignacio; Larsen, Steen;

    2016-01-01

    PURPOSE: The aim of this study was to determine if the expression of the mitochondrial biogenesis-regulating proteins SIRT1, SIRT3 and PGC-1alpha in human skeletal muscle is influenced by adiposity. METHOD: Twenty-nine male subjects were recruited into three groups: control (n = 10), obese (n = 1...

  14. Epigallocatechin-gallate (EGCG) regulates autophagy in human retinal pigment epithelial cells: A potential role for reducing UVB light-induced retinal damage

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chao-Peng; Yao, Jin; Tao, Zhi-Fu; Li, Xiu-Miao; Jiang, Qin, E-mail: jqin710@vip.sina.com; Yan, Biao, E-mail: yanbiao1982@hotmail.com

    2013-09-06

    Highlights: •UVB irradiation induces RPE autophagy. •EGCG treatment represses UVB-mediated autophagy. •EGCG regulates UVB-mediated autophagy through mTOR signaling pathway. •EGCG sensitizes RPE cells to UVB-induced damage in an autophagy-dependent manner. -- Abstract: Autophagy is an intracellular catabolic process involved in protein and organelle degradation via the lysosomal pathway that has been linked in the pathogenesis of age-related macular degeneration (AMD). UVB irradiation-mediated degeneration of the macular retinal pigment epithelial (RPE) cells is an important hallmark of AMD, which is along with the change in RPE autophagy. Thus, pharmacological manipulation of RPE autophagy may offer an alternative therapeutic target in AMD. Here, we found that epigallocatechin-3-gallate (EGCG), a polyphenolic compound from green tea, plays a regulatory role in UVB irradiation-induced autophagy in RPE cells. UVB irradiation results in a marked increase in the amount of LC3-II protein in a dose-dependent manner. EGCG administration leads to a significant reduction in the formation of LC3-II and autophagosomes. mTOR signaling activation is required for EGCG-induced LC3-II formation, as evidenced by the fact that EGCG-induced LC3-II formation is significantly impaired by rapamycin administration. Moreover, EGCG significantly alleviates the toxic effects of UVB irradiation on RPE cells in an autophagy-dependent manner. Collectively, our study reveals a novel role of EGCG in RPE autophagy. EGCG may be exploited as a potential therapeutic reagent for the treatment of pathological conditions associated with abnormal autophagy.

  15. Biallelic Mutations in the Autophagy Regulator DRAM2 Cause Retinal Dystrophy with Early Macular Involvement

    Science.gov (United States)

    El-Asrag, Mohammed E.; Sergouniotis, Panagiotis I.; McKibbin, Martin; Plagnol, Vincent; Sheridan, Eamonn; Waseem, Naushin; Abdelhamed, Zakia; McKeefry, Declan; Van Schil, Kristof; Poulter, James A.; Black, Graeme; Hall, Georgina; Ingram, Stuart; Gillespie, Rachel; Ramsden, Simon; Manson, Forbes; Hardcastle, Alison; Michaelides, Michel; Cheetham, Michael; Arno, Gavin; Thomas, Niclas; Bhattacharya, Shomi; Moore, Tony; Nemeth, Andrea; Downes, Susan; Lise, Stefano; Lord, Emma; Johnson, Colin A.; Carr, Ian M.; Leroy, Bart P.; De Baere, Elfride; Inglehearn, Chris F.; Webster, Andrew R.; Toomes, Carmel; Ali, Manir

    2015-01-01

    Retinal dystrophies are an overlapping group of genetically heterogeneous conditions resulting from mutations in more than 250 genes. Here we describe five families affected by an adult-onset retinal dystrophy with early macular involvement and associated central visual loss in the third or fourth decade of life. Affected individuals were found to harbor disease-causing variants in DRAM2 (DNA-damage regulated autophagy modulator protein 2). Homozygosity mapping and exome sequencing in a large, consanguineous British family of Pakistani origin revealed a homozygous frameshift variant (c.140delG [p.Gly47Valfs∗3]) in nine affected family members. Sanger sequencing of DRAM2 in 322 unrelated probands with retinal dystrophy revealed one European subject with compound heterozygous DRAM2 changes (c.494G>A [p.Trp165∗] and c.131G>A [p.Ser44Asn]). Inspection of previously generated exome sequencing data in unsolved retinal dystrophy cases identified a homozygous variant in an individual of Indian origin (c.64_66del [p.Ala22del]). Independently, a gene-based case-control association study was conducted via an exome sequencing dataset of 18 phenotypically similar case subjects and 1,917 control subjects. Using a recessive model and a binomial test for rare, presumed biallelic, variants, we found DRAM2 to be the most statistically enriched gene; one subject was a homozygote (c.362A>T [p.His121Leu]) and another a compound heterozygote (c.79T>C [p.Tyr27His] and c.217_225del [p.Val73_Tyr75del]). DRAM2 encodes a transmembrane lysosomal protein thought to play a role in the initiation of autophagy. Immunohistochemical analysis showed DRAM2 localization to photoreceptor inner segments and to the apical surface of retinal pigment epithelial cells where it might be involved in the process of photoreceptor renewal and recycling to preserve visual function. PMID:25983245

  16. Longevity-relevant regulation of autophagy at the level of the acetylproteome

    DEFF Research Database (Denmark)

    Mariño, Guillermo; Morselli, Eugenia; Bennetzen, Martin V;

    2011-01-01

    The acetylase inhibitor, spermidine and the deacetylase activator, resveratrol, both induce autophagy and prolong life span of the model organism Caenorhabditis elegans in an autophagydependent fashion. Based on these premises, we investigated the differences and similarities in spermidine...... and resveratrol-induced autophagy. The deacetylase sirtuin 1 (SIRT1) and its orthologs are required for the autophagy induction by resveratrol but dispensable for autophagy stimulation by spermidine in human cells, Saccharomyces cerevisiae and C. elegans. SIRT1 is also dispensable for life-span extension...... by spermidine. Mass spectrometry analysis of the human acetylproteome revealed that resveratrol and/or spermidine induce changes in the acetylation of 560 peptides corresponding to 375 different proteins. Among these, 170 proteins are part of the recently elucidated human autophagy protein network. Importantly...

  17. Thioredoxin Binding Protein-2 Regulates Autophagy of Human Lens Epithelial Cells under Oxidative Stress via Inhibition of Akt Phosphorylation

    Science.gov (United States)

    Yao, Ke; Zhang, Yidong; Chen, Guangdi; Lai, Kairan; Yin, Houfa

    2016-01-01

    Oxidative stress plays an essential role in the development of age-related cataract. Thioredoxin binding protein-2 (TBP-2) is a negative regulator of thioredoxin (Trx), which deteriorates cellular antioxidant system. Our study focused on the autophagy-regulating effect of TBP-2 under oxidative stress in human lens epithelial cells (LECs). Human lens epithelial cells were used for cell culture and treatment. Lentiviral-based transfection system was used for overexpression of TBP-2. Cytotoxicity assay, western blot analysis, GFP/mCherry-fused LC3 plasmid, immunofluorescence, and transmission electronic microscopy were performed. The results showed that autophagic response of LECs with increased LC3-II, p62, and GFP/mCherry-LC3 puncta (P < 0.01) was induced by oxidative stress. Overexpression of TBP-2 further strengthens this response and worsens the cell viability (P < 0.01). Knockdown of TBP-2 attenuates the autophagic response and cell viability loss induced by oxidative stress. TBP-2 mainly regulates autophagy in the initiation stage, which is mTOR-independent and probably caused by the dephosphorylation of Akt under oxidative stress. These findings suggest a novel role of TBP-2 in human LECs under oxidative stress. Oxidative stress can cause cell injury and autophagy in LECs, and TBP-2 regulates this response. Hence, this study provides evidence regarding the role of TBP-2 in lens and the possible mechanism of cataract development. PMID:27656263

  18. Up-Regulated Expression of LAMP2 and Autophagy Activity during Neuroendocrine Differentiation of Prostate Cancer LNCaP Cells

    Science.gov (United States)

    Vara-Ciruelos, Diana; Ramos-Torres, Ágata; Altamirano-Dimas, Manuel; Díaz-Laviada, Inés; Rodríguez-Henche, Nieves

    2016-01-01

    Neuroendocrine (NE) prostate cancer (PCa) is a highly aggressive subtype of prostate cancer associated with resistance to androgen ablation therapy. In this study, we used LNCaP prostate cancer cells cultured in a serum-free medium for 6 days as a NE model of prostate cancer. Serum deprivation increased the expression of NE markers such as neuron-specific enolase (NSE) and βIII tubulin (βIII tub) and decreased the expression of the androgen receptor protein in LNCaP cells. Using cDNA microarrays, we compared gene expression profiles of NE cells and non-differentiated LNCaP cells. We identified up-regulation of 155 genes, among them LAMP2, a lysosomal membrane protein involved in lysosomal stability and autophagy. We then confirmed up-regulation of LAMP2 in NE cells by qRT-PCR, Western blot and confocal microscopy assays, showing that mRNA up-regulation correlated with increased levels of LAMP2 protein. Subsequently, we determined autophagy activity in NE cells by assessing the protein levels of SQSTM/p62 and LC3 by Western blot and LC3 and Atg5 mRNAs content by qRT-PCR. The decreased levels of SQSTM/p62 was accompanied by an enhanced expression of LC3 and ATG5, suggesting activation of autophagy in NE cells. Blockage of autophagy with 1μM AKT inhibitor IV, or by silencing Beclin 1 and Atg5, prevented NE cell differentiation, as revealed by decreased levels of the NE markers. In addition, AKT inhibitor IV as well as Beclin1 and Atg5 kwockdown attenuated LAMP2 expression in NE cells. On the other hand, LAMP2 knockdown by siRNA led to a marked blockage of autophagy, prevention of NE differentiation and decrease of cell survival. Taken together, these results suggest that LAMP2 overexpression assists NE differentiation of LNCaP cells induced by serum deprivation and facilitates autophagy activity in order to attain the NE phenotype and cell survival. LAMP2 could thus be a potential biomarker and potential target for NE prostate cancer. PMID:27627761

  19. Autophagy regulates the therapeutic potential of mesenchymal stem cells in experimental autoimmune encephalomyelitis.

    Science.gov (United States)

    Dang, Shipeng; Xu, Huanbai; Xu, Congfeng; Cai, Wei; Li, Qian; Cheng, Yiji; Jin, Min; Wang, Ru-Xing; Peng, Yongde; Zhang, Yi; Wu, Changping; He, Xiaozhou; Wan, Bing; Zhang, Yanyun

    2014-07-01

    Mesenchymal stem cell (MSC)-based therapy is a promising approach to treat various inflammatory disorders including multiple sclerosis. However, the fate of MSCs in the inflammatory microenvironment is largely unknown. Experimental autoimmune encephalomyelitis (EAE) is a well-studied animal model of multiple sclerosis. We demonstrated that autophagy occurred in MSCs during their application for EAE treatment. Inflammatory cytokines, e.g., interferon gamma and tumor necrosis factor, induced autophagy in MSCs synergistically by inducing expression of BECN1/Beclin 1. Inhibition of autophagy by knockdown of Becn1 significantly improved the therapeutic effects of MSCs on EAE, which was mainly attributable to enhanced suppression upon activation and expansion of CD4(+) T cells. Mechanistically, inhibition of autophagy increased reactive oxygen species generation and mitogen-activated protein kinase 1/3 activation in MSCs, which were essential for PTGS2 (prostaglandin-endoperoxide synthase 2 [prostaglandin G/H synthase and cyclooxygenase]) and downstream prostaglandin E2 expression to exert immunoregulatory function. Furthermore, pharmacological treatment of MSCs to inhibit autophagy increased their immunosuppressive effects on T cell-mediated EAE. Our findings indicate that inflammatory microenvironment-induced autophagy downregulates the immunosuppressive function of MSCs. Therefore, modulation of autophagy in MSCs would provide a novel strategy to improve MSC-based immunotherapy.

  20. Regulation of HSL serine phosphorylation in skeletal muscle and adipose tissue.

    Science.gov (United States)

    Watt, Matthew J; Holmes, Anna G; Pinnamaneni, Srijan K; Garnham, Andrew P; Steinberg, Gregory R; Kemp, Bruce E; Febbraio, Mark A

    2006-03-01

    Hormone-sensitive lipase (HSL) is important for the degradation of triacylglycerol in adipose and muscle tissue, but the tissue-specific regulation of this enzyme is not fully understood. We investigated the effects of adrenergic stimulation and AMPK activation in vitro and in circumstances where AMPK activity and catecholamines are physiologically elevated in humans in vivo (during physical exercise) on HSL activity and phosphorylation at Ser(563) and Ser(660), the PKA regulatory sites, and Ser(565), the AMPK regulatory site. In human experiments, skeletal muscle, subcutaneous adipose and venous blood samples were obtained before, at 15 and 90 min during, and 120 min after exercise. Skeletal muscle HSL activity was increased by approximately 80% at 15 min compared with rest and returned to resting rates at the cessation of and 120 min after exercise. Consistent with changes in plasma epinephrine, skeletal muscle HSL Ser(563) and Ser(660) phosphorylation were increased by 27% at 15 min (P HSL Ser(565) phosphorylation and AMPK signaling were increased at 90 min during, and after, exercise. Phosphorylation of adipose tissue HSL paralleled changes in skeletal muscle in vivo, except HSL Ser(660) was elevated 80% in adipose compared with 35% in skeletal muscle during exercise. Studies in L6 myotubes and 3T3-L1 adipocytes revealed important tissue differences in the regulation of HSL. AMPK inhibited epinephrine-induced HSL activity in L6 myotubes and was associated with reduced HSL Ser(660) but not Ser(563) phosphorylation. HSL activity was reduced in L6 myotubes expressing constitutively active AMPK, confirming the inhibitory effects of AMPK on HSL activity. Conversely, in 3T3-L1 adipocytes, AMPK activation after epinephrine stimulation did not prevent HSL activity or glycerol release, which coincided with maintenance of HSL Ser(660) phosphorylation. Taken together, these data indicate that HSL activity is maintained in the face of AMPK activation as a result of

  1. 4E-BP1 regulates the differentiation of white adipose tissue.

    Science.gov (United States)

    Tsukiyama-Kohara, Kyoko; Katsume, Asao; Kimura, Kazuhiro; Saito, Masayuki; Kohara, Michinori

    2013-07-01

    4E Binding protein 1 (4E-BP1) suppresses translation initiation. The absence of 4E-BP1 drastically reduces the amount of adipose tissue in mice. To address the role of 4E-BP1 in adipocyte differentiation, we characterized 4E-BP1(-/-) mice in this study. The lack of 4E-BP1 decreased the amount of white adipose tissue and increased the amount of brown adipose tissue. In 4E-BP1(-/-) MEF cells, PPARγ coactivator 1 alpha (PGC-1α) expression increased and exogenous 4E-BP1 expression suppressed PGC-1α expression. The level of 4E-BP1 expression was higher in white adipocytes than in brown adipocytes and showed significantly greater up-regulation in white adipocytes than in brown adipocytes during preadipocyte differentiation into mature adipocytes. The amount of PGC-1α was consistently higher in HB cells (a brown preadipocyte cell line) than in HW cells (a white preadipocyte cell line) during differentiation. Moreover, the ectopic over-expression of 4E-BP1 suppressed PGC-1α expression in white adipocytes, but not in brown adipocytes. Thus, the results of our study indicate that 4E-BP1 may suppress brown adipocyte differentiation and PGC-1α expression in white adipose tissues.

  2. ADIPOSE TRIGLYCERIDE LIPASE REGULATES BASAL LIPOLYSIS AND LIPID DROPLET SIZE IN ADIPOCYTES

    OpenAIRE

    Miyoshi, Hideaki; Perfield, James W.; Obin, Martin S.; Greenberg, Andrew S.

    2008-01-01

    In adipocytes, lipid droplet (LD) size reflects a balance of triglyceride synthesis (lipogenesis) and hydrolysis (lipolysis). Perilipin A (Peri A), is the most abundant phosphoprotein on the surface of adipocyte LDs and has a crucial role in lipid storage and lipolysis. Adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL) are the major rate-determining enzymes for lipolysis in adipocytes. Each of these proteins (Peri A, ATGL and HSL) have been demonstrated to regulate lipid s...

  3. Conjugated Linoleic Acid in Humans: Regulation of Adiposity and Insulin Sensitivity1,2

    OpenAIRE

    Brown, J. Mark; McIntosh, Michael K.

    2003-01-01

    Conjugated linoleic acid (CLA) isomers, a group of positional and geometric isomers of linoleic acid [18:2(n-6)], have been studied extensively due to their ability to modulate cancer, atherosclerosis, obesity, immune function and diabetes in a variety of experimental models. The purpose of this review was to examine CLA’s isomer-specific regulation of adiposity and insulin sensitivity in humans and in cultures of human adipocytes. It has been clearly demonstrated that specific CLA isomers or...

  4. The regulation of HSL and LPL expression by DHT and flutamide in human subcutaneous adipose tissue.

    Science.gov (United States)

    Anderson, L A; McTernan, P G; Harte, A L; Barnett, A H; Kumar, S

    2002-05-01

    Clinical observations suggest a role for testosterone in the accumulation of central adiposity and with an associated increased risk of disease. To date, no human study has analysed the role of dihydrotestosterone (DHT) on adipose tissue mass regulation in vitro. This study investigated the role of DHT and androgen receptors (AR) in the regulation of lipolysis and lipogenesis by examining the key enzymes hormone sensitive lipase (HSL) and lipoprotein lipase (LPL) respectively. Isolated abdominal subcutaneous adipocytes (Scad) (n = 15) were treated with either DHT (10(-7)-10(-9) m), an antiandrogen, flutamide (FLT: 10(-7)-10(-9) m) or a combination of DHT (10(-7)-10(-9) m) with FLT (10(-8) m). Relative protein expression of HSL, LPL and AR was determined. In Scad, DHT inhibited HSL expression maximally at 10(-9) m (0.7 +/- 0.4**; p HSL expression data. LPL expression was reduced at all doses with combinations of DHT + FLT compared with DHT alone. Androgen receptor expression studies showed an inverse correlation with DHT, whereas DHT + FLT reduced AR expression. These studies indicate that DHT may alter HSL and LPL expression, whereas only LPL expression appears mediated by AR. These findings suggest a physiological role for DHT in the control of adipose tissue mass in women, and indicate that androgens may also play an important role in regulating lipid metabolism.

  5. Autophagy in infection.

    Science.gov (United States)

    Deretic, Vojo

    2010-04-01

    Autophagy is a ubiquitous eukaryotic cytoplasmic quality and quantity control pathway. The role of autophagy in cytoplasmic homeostasis seamlessly extends to cell-autonomous defense against intracellular microbes. Recent studies also point to fully integrated, multitiered regulatory and effector connections between autophagy and nearly all facets of innate and adaptive immunity. Autophagy in the immune system as a whole confers measured immune responses; on the flip side, suppression of autophagy can lead to inflammation and tissue damage, as evidenced by Crohn's disease predisposition polymorphisms in autophagy basal apparatus (Atg16L) and regulatory (IRGM) genes. Polymorphisms in the IRGM gene in human populations have also been linked to predisposition to tuberculosis. There are several areas of most recent growth: first, links between autophagy regulators and infectious disease predisposition in human populations; second, demonstration of a role for autophagy in infection control in vivo in animal models; third, the definition of specific antiautophagic defenses in highly evolved pathogens; and fourth, recognition of connections between the ubiquitin system and autophagy of bacteria (and interestingly mitochondria, which are incidentally organelles of bacterial evolutionary origin) via a growing list of modifier and adapter proteins including p62/SQSTM1, NDP52, Atg32, Parkin, and Nix/BNIP3L. PMID:20116986

  6. Selective Autophagy in Drosophila

    Directory of Open Access Journals (Sweden)

    Ioannis P. Nezis

    2012-01-01

    Full Text Available Autophagy is an evolutionarily conserved process of cellular self-eating and is a major pathway for degradation of cytoplasmic material by the lysosomal machinery. Autophagy functions as a cellular response in nutrient starvation, but it is also associated with the removal of protein aggregates and damaged organelles and therefore plays an important role in the quality control of proteins and organelles. Although it was initially believed that autophagy occurs randomly in the cell, during the last years, there is growing evidence that sequestration and degradation of cytoplasmic material by autophagy can be selective. Given the important role of autophagy and selective autophagy in several disease-related processes such as neurodegeneration, infections, and tumorigenesis, it is important to understand the molecular mechanisms of selective autophagy, especially at the organismal level. Drosophila is an excellent genetically modifiable model organism exhibiting high conservation in the autophagic machinery. However, the regulation and mechanisms of selective autophagy in Drosophila have been largely unexplored. In this paper, I will present an overview of the current knowledge about selective autophagy in Drosophila.

  7. HnRNP K contributes to drug resistance in acute myeloid leukemia through the regulation of autophagy.

    Science.gov (United States)

    Zhang, JinFang; Liu, XiaoLi; Lin, YuDeng; Li, YuLing; Pan, JianWei; Zong, Sa; Li, YongKang; Zhou, Yang

    2016-09-01

    The goal of this study was to explore the role of heterogeneous nuclear ribonucleoprotein K (hnRNP K) in drug resistance through the regulation of autophagy in acute myeloid leukemia (AML). First, we used fluorescence quantitative polymerase chain reaction (PCR) to verify the connection between the expression level of hnRNP K and the level of drug resistance in AML. We then used Western blotting to determine the expression level of the autophagy-related proteins microtubule-associated protein light chain 3 I and II (LC3 I/II) after the modulation of hnRNP K by ribonucleic acid (RNA) interference. Finally, an analysis of adriamycin drug sensitivity was conducted before and after the modulation of hnRNP K expression. hnRNP K and LC3 I/II were significantly overexpressed in the bone marrow of nonremission patients and in drug-resistant cell lines; however, the expression of LC3 I/II was decreased when the expression of hnRNP K was reduced and drug sensitivity to adriamycin could be restored. hnRNP K may be involved in the development of adriamycin resistance in AML through the regulation of autophagy.

  8. Spermine ameliorates ischemia/reperfusion injury in cardiomyocytes via regulation of autophagy

    Science.gov (United States)

    Duan, Qunjun; Yang, Weijun; Jiang, Daming; Tao, Kaiyu; Dong, Aiqiang; Cheng, Haifeng

    2016-01-01

    Myocardial infarction could result in high morbidity and mortality and heart diseases of children have becoming prevalent. Functions of spermine administration on cardiomyocytes remain unknown. The present study was designed to investigate the role of spermine pretreatment on myocardial ischemia/reperfusion injury (IRI). A cell model of simulated ischemia/reperfusion injury was established by incubating neonatal Sprague-Dawley rat cardiomyocytes in ischemia medium and re-cultured in normal medium. Of note, spermine pretreatment significantly reduced apoptosis and increased viability of immature cardiomyocytes. Spermine pretreatment enhanced autophagic flux as determined by confocal microscopy and transmission electron microscopy. Furthermore, proteins of mammalian target of rapamycin (mTOR) pathway were significantly reduced in response to spermine pretreatment during IRI, while proteins related to autophagy were up-regulated. The cell viability was enhanced and apoptosis decreased by rapamycin after spermine pretreatment, while these were reversed by 3-methyladenine. However, when immature cardiomyocytes were pretreated with rapamycin or 3-methyladenine, followed by IRI and spermine administration, no significant changes of viability and apoptosis were observed. In conclusion, this study suggests that spermine is a potential novel approach for preventing IRI, especially in children. PMID:27725878

  9. Rev-erb-α modulates skeletal muscle oxidative capacity by regulating mitochondrial biogenesis and autophagy

    Science.gov (United States)

    Woldt, Estelle; Sebti, Yasmine; Solt, Laura A.; Duhem, Christian; Lancel, Steve; Eeckhoute, Jérôme; Hesselink, Matthijs K.C.; Paquet, Charlotte; Delhaye, Stéphane; Shin, Youseung; Kamenecka, Theodore M.; Schaart, Gert; Lefebvre, Philippe; Nevière, Rémi; Burris, Thomas P.; Schrauwen, Patrick; Staels, Bart; Duez, Hélène

    2013-01-01

    The nuclear receptor Rev-erb-α modulates hepatic lipid and glucose metabolism, adipogenesis and the inflammatory response in macrophages. We show here that Rev-erb-α is highly expressed in oxidative skeletal muscle and plays a role in mitochondrial biogenesis and oxidative function, in gain- and loss-of function studies. Rev-erb-α-deficiency in skeletal muscle leads to reduced mitochondrial content and oxidative function, resulting in compromised exercise capacity. This phenotype was recapitulated in isolated fibers and in muscle cells upon Rev-erbα knock-down, while Rev-erb-α over-expression increased the number of mitochondria with improved respiratory capacity. Rev-erb-α-deficiency resulted in deactivation of the Stk11–Ampk–Sirt1–Ppargc1-α signaling pathway, whereas autophagy was up-regulated, resulting in both impaired mitochondrial biogenesis and increased clearance. Muscle over-expression or pharmacological activation of Rev-erb-α increased respiration and exercise capacity. This study identifies Rev-erb-α as a pharmacological target which improves muscle oxidative function by modulating gene networks controlling mitochondrial number and function. PMID:23852339

  10. Role of AMPK in regulation of LC3 lipidation as a marker of autophagy in skeletal muscle

    DEFF Research Database (Denmark)

    Fritzen, Andreas Mæchel; Frøsig, Christian; Jeppesen, Jacob Fuglsbjerg;

    2016-01-01

    During induction of the autophagosomal degradation process, LC3-I is lipidated to LC3-II and associates to the cargo isolation membrane allowing for autophagosome formation. Lipidation of LC3 results in an increased LC3-II/LC3-I ratio, and this ratio is an often used marker for autophagy in various...... tissues, including skeletal muscle. From cell studies AMPK has been proposed to be necessary and sufficient for LC3 lipidation. The aim of the present study was to investigate the role of AMPK in regulation of LC3 lipidation as a marker of autophagy in skeletal muscle. We observed an increase in the LC3.......01) in plasma insulin concentration, a subsequent decrease in muscle mTORC1 signaling and increased (pautophagy-promoting proteins, FoxO3a and ULK1. Furthermore, a higher (p

  11. RIPK1 regulates survival of human melanoma cells upon endoplasmic reticulum stress through autophagy.

    Science.gov (United States)

    Luan, Qi; Jin, Lei; Jiang, Chen Chen; Tay, Kwang Hong; Lai, Fritz; Liu, Xiao Ying; Liu, Yi Lun; Guo, Su Tang; Li, Chun Ying; Yan, Xu Guang; Tseng, Hsin-Yi; Zhang, Xu Dong

    2015-01-01

    Although RIPK1 (receptor [TNFRSF]-interacting protein kinase 1) is emerging as a critical determinant of cell fate in response to cellular stress resulting from activation of death receptors and DNA damage, its potential role in cell response to endoplasmic reticulum (ER) stress remains undefined. Here we report that RIPK1 functions as an important prosurvival mechanism in melanoma cells undergoing pharmacological ER stress induced by tunicamycin (TM) or thapsigargin (TG) through activation of autophagy. While treatment with TM or TG upregulated RIPK1 and triggered autophagy in melanoma cells, knockdown of RIPK1 inhibited autophagy and rendered the cells sensitive to killing by TM or TG, recapitulating the effect of inhibition of autophagy. Consistently, overexpression of RIPK1 enhanced induction of autophagy and conferred resistance of melanoma cells to TM- or TG-induced cell death. Activation of MAPK8/JNK1 or MAPK9/JNK2, which phosphorylated BCL2L11/BIM leading to its dissociation from BECN1/Beclin 1, was involved in TM- or TG-induced, RIPK1-mediated activation of autophagy; whereas, activation of the transcription factor HSF1 (heat shock factor protein 1) downstream of the ERN1/IRE1-XBP1 axis of the unfolded protein response was responsible for the increase in RIPK1 in melanoma cells undergoing pharmacological ER stress. Collectively, these results identify upregulation of RIPK1 as an important resistance mechanism of melanoma cells to TM- or TG-induced ER stress by protecting against cell death through activation of autophagy, and suggest that targeting the autophagy-activating mechanism of RIPK1 may be a useful strategy to enhance sensitivity of melanoma cells to therapeutic agents that induce ER stress.

  12. Egr-1 regulates autophagy in cigarette smoke-induced chronic obstructive pulmonary disease.

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    Zhi-Hua Chen

    Full Text Available BACKGROUND: Chronic obstructive pulmonary disease (COPD is a progressive lung disease characterized by abnormal cellular responses to cigarette smoke, resulting in tissue destruction and airflow limitation. Autophagy is a degradative process involving lysosomal turnover of cellular components, though its role in human diseases remains unclear. METHODOLOGY AND PRINCIPAL FINDINGS: Increased autophagy was observed in lung tissue from COPD patients, as indicated by electron microscopic analysis, as well as by increased activation of autophagic proteins (microtubule-associated protein-1 light chain-3B, LC3B, Atg4, Atg5/12, Atg7. Cigarette smoke extract (CSE is an established model for studying the effects of cigarette smoke exposure in vitro. In human pulmonary epithelial cells, exposure to CSE or histone deacetylase (HDAC inhibitor rapidly induced autophagy. CSE decreased HDAC activity, resulting in increased binding of early growth response-1 (Egr-1 and E2F factors to the autophagy gene LC3B promoter, and increased LC3B expression. Knockdown of E2F-4 or Egr-1 inhibited CSE-induced LC3B expression. Knockdown of Egr-1 also inhibited the expression of Atg4B, a critical factor for LC3B conversion. Inhibition of autophagy by LC3B-knockdown protected epithelial cells from CSE-induced apoptosis. Egr-1(-/- mice, which displayed basal airspace enlargement, resisted cigarette-smoke induced autophagy, apoptosis, and emphysema. CONCLUSIONS: We demonstrate a critical role for Egr-1 in promoting autophagy and apoptosis in response to cigarette smoke exposure in vitro and in vivo. The induction of autophagy at early stages of COPD progression suggests novel therapeutic targets for the treatment of cigarette smoke induced lung injury.

  13. Globular Adiponectin Causes Tolerance to LPS-Induced TNF-α Expression via Autophagy Induction in RAW 264.7 Macrophages: Involvement of SIRT1/FoxO3A Axis

    OpenAIRE

    Tilija Pun, Nirmala; Subedi, Amit; Kim, Mi Jin; Park, Pil-Hoon

    2015-01-01

    Adiponectin, an adipokine predominantly produced from adipose tissue, exhibited potent anti-inflammatory properties. In particular, it inhibits production of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), in macrophages. Autophagy, an intracellular self-digestion process, has been recently shown to regulate inflammatory responses. In the present study, we investigated the role of autophagy induction in the suppression of Lipopolysaccharide (LPS) -induced TNF-α expressi...

  14. Cyclophilin D Is Involved in the Regulation of Autophagy and Affects the Lifespan of P. anserina in Response to Mitochondrial Oxidative Stress

    Science.gov (United States)

    Kramer, Piet; Jung, Alexander T.; Hamann, Andrea; Osiewacz, Heinz D.

    2016-01-01

    The mitochondrial permeability transition pore plays a key role in programmed cell death and the induction of autophagy. Opening of the pore is regulated by the mitochondrial peptidyl prolyl-cis, trans-isomerase cyclophilin D (CYPD). Previously it was shown in the aging model organism Podospora anserina that PaCYPD abundance increases during aging and that PaCypD overexpressors are characterized by accelerated aging. Here, we describe a role of PaCYPD in the regulation of autophagy. We found that the accelerated aging phenotype observed in a strain overexpressing PaCypD is not metacaspase-dependent but is accompanied by an increase of general autophagy and mitophagy, the selective autophagic degradation of mitochondria. It thus is linked to what has been defined as “autophagic cell death” or “type II” programmed cell death. Moreover, we found that the previously demonstrated age-related induction of autophagy in wild-type aging depends on the presence of PaCYPD. Deletion of PaCypD leads to a decrease in autophagy in later stages of age and under paraquat-mediated oxidative stress. Finally, we report that PaCYPD is also required for mitohormesis, the beneficial effect of mild mitochondrial stress. Thus, PaCYPD plays a key role in the context-dependent regulation of pathways leading to pro-survival and pro-death effects of autophagy. PMID:27683587

  15. Cyclophilin D Is Involved in the Regulation of Autophagy and Affects the Lifespan of P. anserina in Response to Mitochondrial Oxidative Stress.

    Science.gov (United States)

    Kramer, Piet; Jung, Alexander T; Hamann, Andrea; Osiewacz, Heinz D

    2016-01-01

    The mitochondrial permeability transition pore plays a key role in programmed cell death and the induction of autophagy. Opening of the pore is regulated by the mitochondrial peptidyl prolyl-cis, trans-isomerase cyclophilin D (CYPD). Previously it was shown in the aging model organism Podospora anserina that PaCYPD abundance increases during aging and that PaCypD overexpressors are characterized by accelerated aging. Here, we describe a role of PaCYPD in the regulation of autophagy. We found that the accelerated aging phenotype observed in a strain overexpressing PaCypD is not metacaspase-dependent but is accompanied by an increase of general autophagy and mitophagy, the selective autophagic degradation of mitochondria. It thus is linked to what has been defined as "autophagic cell death" or "type II" programmed cell death. Moreover, we found that the previously demonstrated age-related induction of autophagy in wild-type aging depends on the presence of PaCYPD. Deletion of PaCypD leads to a decrease in autophagy in later stages of age and under paraquat-mediated oxidative stress. Finally, we report that PaCYPD is also required for mitohormesis, the beneficial effect of mild mitochondrial stress. Thus, PaCYPD plays a key role in the context-dependent regulation of pathways leading to pro-survival and pro-death effects of autophagy. PMID:27683587

  16. Autophagy regulates the apoptosis of bone marrow-derived mesenchymal stem cells under hypoxic condition via AMP-activated protein kinase/mammalian target of rapamycin pathway.

    Science.gov (United States)

    Zhang, Zheng; Yang, Ming; Wang, Yabin; Wang, Le; Jin, Zhitao; Ding, Liping; Zhang, Lijuan; Zhang, Lina; Jiang, Wei; Gao, Guojie; Yang, Junke; Lu, Bingwei; Cao, Feng; Hu, Taohong

    2016-06-01

    Bone marrow-derived mesenchymal stem cells (BM-MSCs) have been demonstrated as an ideal autologous stem cells source for cell-based therapy for myocardial infarction (MI). However, poor viability of donor stem cells after transplantation limits their therapeutic efficiency, whereas the underlying mechanism is still poorly understood. Autophagy, a highly conserved process of cellular degradation, is required for maintaining homeostasis and normal function. Here, we investigated the potential role of autophagy on apoptosis in BM-MSCs induced by hypoxic injury. BM-MSCs, isolated from male C57BL/6 mice, were subjected to hypoxia and serum deprivation (H/SD) injury for 6, 12, and 24 h, respectively. The autophagy state was regulated by 3-methyladenine (3MA) and rapamycin administration. Furthermore, compound C was administrated to inhibit AMPK. The apoptosis induced by H/SD was determined by TUNEL assays. Meanwhile, autophagy was measured by GFP-LC3 plasmids transfection and transmission electron microscope. Moreover, protein expressions were evaluated by Western blot assay. In the present study, we found that hypoxic stress increased autophagy and apoptosis in BM-MSCs time dependently. Meanwhile, hypoxia increased the activity of AMPK/mTOR signal pathway. Moreover, increased apoptosis in BM-MSCs under hypoxia was abolished by 3-MA, whereas was aggravated by rapamycin. Furthermore, the increased autophagy and apoptosis in BM-MSCs induced by hypoxia were abolished by AMPK inhibitor compound C. These data provide evidence that hypoxia induced AMPK/mTOR signal pathway activation which regulated the apoptosis and autophagy in BM-MSCs. Furthermore, the apoptosis of BM-MSCs under hypoxic condition was regulated by autophagy via AMPK/mTOR pathway. PMID:27005844

  17. Regulation of lipogenesis by glucocorticoids and insulin in human adipose tissue.

    Directory of Open Access Journals (Sweden)

    Laura L Gathercole

    Full Text Available Patients with glucocorticoid (GC excess, Cushing's syndrome, develop a classic phenotype characterized by central obesity and insulin resistance. GCs are known to increase the release of fatty acids from adipose, by stimulating lipolysis, however, the impact of GCs on the processes that regulate lipid accumulation has not been explored. Intracellular levels of active GC are dependent upon the activity of 11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1 and we have hypothesized that 11β-HSD1 activity can regulate lipid homeostasis in human adipose tissue (Chub-S7 cell line and primary cultures of human subcutaneous (sc and omental (om adipocytes. Across adipocyte differentiation, lipogenesis increased whilst β-oxidation decreased. GC treatment decreased lipogenesis but did not alter rates of β-oxidation in Chub-S7 cells, whilst insulin increased lipogenesis in all adipocyte cell models. Low dose Dexamethasone pre-treatment (5 nM of Chub-S7 cells augmented the ability of insulin to stimulate lipogenesis and there was no evidence of adipose tissue insulin resistance in primary sc cells. Both cortisol and cortisone decreased lipogenesis; selective 11β-HSD1 inhibition completely abolished cortisone-mediated repression of lipogenesis. GCs have potent actions upon lipid homeostasis and these effects are dependent upon interactions with insulin. These in vitro data suggest that manipulation of GC availability through selective 11β-HSD1 inhibition modifies lipid homeostasis in human adipocytes.

  18. Atorvastatin induces autophagy of mesenchymal stem cells under hypoxia and serum deprivation conditions by activating the mitogenactivated protein kinase/extracellular signal-regulated kinase pathway

    Institute of Scientific and Technical Information of China (English)

    Li Na; Zhang Qian; Qian Haiyan; Jin Chen; Yang Yuejin; Gao Runlin

    2014-01-01

    Background The survival ratio of implanted mesenchymal stem cells (MSCs) in the infarcted myocardium is low.Autophagy is a complex "self-eating" process and can be utilized for cell survival.We have found that atorvastatin (ATV) can effectively activate autophagy to enhance MSCs survival during hypoxia and serum deprivation (H/SD).The mitogenactivated protein kinase/extracellular signal-regulated kinase (MEK/ERK) pathway is a non-canonical autophagy pathway.We hypothesized that the MEK/ERK pathway mediated ATV-induced autophagy of MSCs under H/SD.Methods MSCs were pretreated with ATV (0.01-10 μmol/L) under H/SD for three hours.For inhibitor studies,the cells were pre-incubated with the MEK1/2 inhibitor U0126.Cell autophagy was assessed by acidic vesicular organelles (AVO)-positive cells using flow cytometry,autophagy related protein using Western blotting and autophagosome using transmission electron microscopy.Results Autophagy was elevated in the H/SD group compared with the normal group.ATV further enhanced the autophagic activity as well as the phosphorylation of ERK1/2 evidenced by more AVO-positive cells ((8.63±0.63)% vs.(5.77±0.44)%,P <0.05),higher LC3-Ⅱ/LC3-Ⅰ ratio (4.36±0.31 vs.2.52±0.18,P <0.05) and more autophagosomes.And treatment with U0126 downregulated the phosphorylation of ERK1/2 and attenuated ATV-induced autophagy.Conclusion The MEK/ERK pathway participates in ATV-induced autophagy in MSCs under H/SD,and modulation of the pathway could be a novel strategy to improve MSCs survival.

  19. Nutrient Regulation: Conjugated Linoleic Acid's Inflammatory and Browning Properties in Adipose Tissue.

    Science.gov (United States)

    Shen, Wan; McIntosh, Michael K

    2016-07-17

    Obesity is the most widespread nutritional disease in the United States. Developing effective and safe strategies to manage excess body weight is therefore of paramount importance. One potential strategy to reduce obesity is to consume conjugated linoleic acid (CLA) supplements containing isomers cis-9, trans-11 and trans-10, cis-12, or trans-10, cis-12 alone. Proposed antiobesity mechanisms of CLA include regulation of (a) adipogenesis, (b) lipid metabolism, (c) inflammation, (d) adipocyte apoptosis, (e) browning or beiging of adipose tissue, and (f) energy metabolism. However, causality of CLA-mediated responses to body fat loss, particularly the linkage between inflammation, thermogenesis, and energy metabolism, is unclear. This review examines whether CLA's antiobesity properties are due to inflammatory signaling and considers CLA's linkage with lipogenesis, lipolysis, thermogenesis, and browning of white and brown adipose tissue. We propose a series of questions and studies to interrogate the role of the sympathetic nervous system in mediating CLA's antiobesity properties. PMID:27431366

  20. Down-regulation of Zac1 gene expression in rat white adipose tissue by androgens.

    Science.gov (United States)

    Mirowska, Agnieszka; Sledzinski, Tomasz; Smolenski, Ryszard T; Swierczynski, Julian

    2014-03-01

    ZAC1 is a zinc-finger protein transcription factor, a transcriptional cofactor for nuclear receptors, and a co-activator of nuclear receptors, which interacts with multiple signaling pathways affecting apoptosis, cell cycle arrest, and metabolism. Some data suggest that ZAC1 regulates the expression of genes associated with function of adipose tissue. Since there is no information about the levels of Zac1 gene expression in white adipose tissue (WAT), and the expression of several genes associated with metabolic function of WAT is significantly lower in male than female animals, we have examined: (a) the relative ZAC1 mRNA levels in some organs/tissues, including three main depots of WAT, in 3-month-old male rats; (b) the relative ZAC1 mRNA levels in WAT of male and female rats; (c) the effect of orchidectomy and orchidectomy with concomitant testosterone treatment on ZAC1 mRNA and protein levels; (d) the effect of ovariectomy and ovariectomy with concomitant 17β-estradiol treatment on ZAC1 mRNA levels; (e) the effect of dihydrotestosterone on ZAC1 mRNA levels in isolated adipocytes. Our results indicate that: (a) ZAC1 mRNA levels are relatively high in WAT in comparison with other organs/tissues; (b) ZAC1 mRNA levels in subcutaneous WAT are approximately 2-fold lower than in epididymal and retroperitoneal adipose tissue; (c) ZAC1 mRNA levels in WAT of adult female rats are approximately 2-fold higher than in male rats; (d) testosterone is inversely related to ZAC1 mRNA and protein levels in WAT of male rats; and (e) dihydrotestosterone decreases the ZAC1 mRNA levels in adipocytes in dose dependent manner. In conclusion, Zac1 gene is highly expressed in white adipose tissue of adult rats. Androgens could play an important role in down-regulation of the ZAC1 mRNA and protein levels in rats.

  1. Autophagy regulates T lymphocyte proliferation through selective degradation of the cell-cycle inhibitor CDKN1B/p27Kip1.

    Science.gov (United States)

    Jia, Wei; He, Ming-Xiao; McLeod, Ian X; Guo, Jian; Ji, Dong; He, You-Wen

    2015-01-01

    The highly conserved cellular degradation pathway, macroautophagy, regulates the homeostasis of organelles and promotes the survival of T lymphocytes. Previous results indicate that Atg3-, Atg5-, or Pik3c3/Vps34-deficient T cells cannot proliferate efficiently. Here we demonstrate that the proliferation of Atg7-deficient T cells is defective. By using an adoptive transfer and Listeria monocytogenes (LM) mouse infection model, we found that the primary immune response against LM is intrinsically impaired in autophagy-deficient CD8(+) T cells because the cell population cannot expand after infection. Autophagy-deficient T cells fail to enter into S-phase after TCR stimulation. The major negative regulator of the cell cycle in T lymphocytes, CDKN1B, is accumulated in autophagy-deficient naïve T cells and CDKN1B cannot be degraded after TCR stimulation. Furthermore, our results indicate that genetic deletion of one allele of CDKN1B in autophagy-deficient T cells restores proliferative capability and the cells can enter into S-phase after TCR stimulation. Finally, we found that natural CDKN1B forms polymers and is physiologically associated with the autophagy receptor protein SQSTM1/p62 (sequestosome 1). Collectively, autophagy is required for maintaining the expression level of CDKN1B in naïve T cells and selectively degrades CDKN1B after TCR stimulation.

  2. Mycobacterium tuberculosis EIS gene inhibits macrophage autophagy through up-regulation of IL-10 by increasing the acetylation of histone H3.

    Science.gov (United States)

    Duan, Liang; Yi, Min; Chen, Juan; Li, Shengjin; Chen, Weixian

    2016-05-13

    Autophagy plays a crucial role in the progress of Mycobacterium tuberculosis (MTB) infection. Recently, MTB enhanced intracellular survival (EIS) protein was reported to be secreted from MTB cells and linked to the inhibition of autophagy and the intracellular persistence of the pathogen. Here, we investigated the mechanism of EIS-mediated inhibition of autophagy in a human phorbol myristate acetate (PMA)-treated THP-1 cell line as well as in murine macrophages. We confirmed that the presence of EIS led to the inhibition of rapamycin (Rapa)-induced autophagy, while IL-10 gene expression was increased and Akt/mTOR/p70S6K pathway was activated during the process. IL-10 gene silencing led to a significant recovery of EIS-mediated autophagy suppression and decreased activity of the Akt/mTOR/p70S6K pathway. IL-10 promoter activity was unaffected by EIS. Remarkably, EIS increased the acetylation level of histone H3 (Ac-H3), which binds to the SP1 and STAT3 region of the human IL-10 gene promoter sequence. Thus, EIS protein possibly increased IL-10 expression through the regulation of Ac-H3 of its promoter. Our data demonstrated that one possible mechanism of the MTB evasion of autophagy is that the EIS protein up-regulates IL-10 via Ac-H3 and thus activates Akt/mTOR/p70S6K pathway. PMID:27079235

  3. Identification of a novel MTOR activator and discovery of a competing endogenous RNA regulating autophagy in vascular endothelial cells.

    Science.gov (United States)

    Ge, Di; Han, Lei; Huang, ShuYa; Peng, Nan; Wang, PengChong; Jiang, Zheng; Zhao, Jing; Su, Le; Zhang, ShangLi; Zhang, Yun; Kung, HsiangFu; Zhao, BaoXiang; Miao, JunYing

    2014-06-01

    MTOR, a central regulator of autophagy, is involved in cancer and cardiovascular and neurological diseases. Modulating the MTOR signaling balance could be of great significance for numerous diseases. No chemical activators of MTOR have been found, and the urgent challenge is to find novel MTOR downstream components. In previous studies, we found a chemical small molecule, 3-benzyl-5-((2-nitrophenoxy) methyl)-dihydrofuran-2(3H)-one (3BDO), that inhibited autophagy in human umbilical vein endothelial cells (HUVECs) and neuronal cells. Here, we found that 3BDO activated MTOR by targeting FKBP1A (FK506-binding protein 1A, 12 kDa). We next used 3BDO to detect novel factors downstream of the MTOR signaling pathway. Activation of MTOR by 3BDO increased the phosphorylation of TIA1 (TIA1 cytotoxic granule-associated RNA binding protein/T-cell-restricted intracellular antigen-1). Finally, we used gene microarray, RNA interference, RNA-ChIP assay, bioinformatics, luciferase reporter assay, and other assays and found that 3BDO greatly decreased the level of a long noncoding RNA (lncRNA) derived from the 3' untranslated region (3'UTR) of TGFB2, known as FLJ11812. TIA1 was responsible for processing FLJ11812. Further experiments results showed that FLJ11812 could bind with MIR4459 targeting ATG13 (autophagy-related 13), and ATG13 protein level was decreased along with 3BDO-decreased FLJ11812 level. Here, we provide a new activator of MTOR, and our findings highlight the role of the lncRNA in autophagy.

  4. Brown Adipose Tissue Thermogenic Capacity Is Regulated by Elovl6

    Directory of Open Access Journals (Sweden)

    Chong Yew Tan

    2015-12-01

    Full Text Available Although many transcriptional pathways regulating BAT have been identified, the role of lipid biosynthetic enzymes in thermogenesis has been less investigated. Whereas cold exposure causes changes in the fatty acid composition of BAT, the functional consequences of this remains relatively unexplored. In this study, we demonstrate that the enzyme Elongation of Very Long Chain fatty acids 6 (Elovl6 is necessary for the thermogenic action of BAT. Elovl6 is responsible for converting C16 non-essential fatty acids into C18 species. Loss of Elovl6 does not modulate traditional BAT markers; instead, it causes reduced expression of mitochondrial electron transport chain components and lower BAT thermogenic capacity. The reduction in BAT activity appears to be counteracted by increased beiging of scWAT. When beige fat is disabled by thermoneutrality or aging, Elovl6 KO mice gain weight and have increased scWAT mass and impaired carbohydrate metabolism. Overall, our study suggests fatty acid chain length is important for BAT function.

  5. Adipose tissue and adipokines--energy regulation from the human perspective.

    Science.gov (United States)

    Trayhurn, Paul; Bing, Chen; Wood, I Stuart

    2006-07-01

    There has been a rapid rise in the incidence of obesity, primarily as a result of changes in lifestyle (diet and activity levels). Obesity has provided considerable impetus for the investigation of the fundamental mechanisms involved in the regulation of energy balance. Important developments include the identification of novel factors involved in the control of appetite, such as ghrelin, orexin A, and the endogenous cannabinoids, and the emergence of the concept of "nonexercise activity thermogenesis" (NEAT) provided new perspectives on energy expenditure. Studies on white adipose tissue have led to the recognition that it is an important endocrine organ, communicating with the brain and peripheral tissues through the secretion of leptin and other adipokines. There is a rapidly expanding list of protein factors released by white adipose tissue, including the key hormone, adiponectin. Of particular note is the range of cytokines, chemokines, and other inflammation-related proteins secreted by white fat as tissue mass rises; indeed, obesity is characterized by chronic mild inflammation. The adipokines provide an extensive network of communication both within adipose tissue and with other organs, and some are implicated directly in the pathologies associated with obesity, particularly the metabolic syndrome. Although the focus remains very much on obesity in humans, the disorder and its sequelae are also a growing concern in companion animals. PMID:16772463

  6. Irisin and Myonectin Regulation in the Insulin Resistant Muscle: Implications to Adipose Tissue: Muscle Crosstalk

    Directory of Open Access Journals (Sweden)

    Luis Gamas

    2015-01-01

    Full Text Available Myokines are peptides produced and secreted by the skeletal muscle, with autocrine, paracrine, and endocrine actions. Many of them are overexpressed during physical exercise and appear to contribute to the benefits of exercise to metabolic homeostasis. Irisin, resulting from the cleavage of the membrane protein FNDC5, was shown to induce adipocyte browning, with increased lipid oxidation and thermogenesis. Myonectin was only recently discovered and initial studies revealed a role in fatty acid uptake and oxidation in adipose tissue and liver. However, the mechanisms of their regulation by exercise are not entirely established. Impaired secretion and action of myokines, such as irisin and myonectin, may have a role in the establishment of insulin resistance. On the other hand, several studies have shown that insulin resistance in the skeletal muscle may change myokines expression and secretion. This may have consequences on lipid and glucose metabolism in adipose tissue and lead to a vicious cycle between impaired myokines production and insulin resistance. This review summarizes the current knowledge about the influence of skeletal muscle insulin resistance on the secretion of irisin and myonectin, as well as its impact on adipose tissue metabolism.

  7. Micro RNA-124a Regulates Lipolysis via Adipose Triglyceride Lipase and Comparative Gene Identification 58

    Directory of Open Access Journals (Sweden)

    Suman K. Das

    2015-04-01

    Full Text Available Lipolysis is the biochemical pathway responsible for the catabolism of cellular triacylglycerol (TG. Lipolytic TG breakdown is a central metabolic process leading to the generation of free fatty acids (FA and glycerol, thereby regulating lipid, as well as energy homeostasis. The precise tuning of lipolysis is imperative to prevent lipotoxicity, obesity, diabetes and other related metabolic disorders. Here, we present our finding that miR-124a attenuates RNA and protein expression of the major TG hydrolase, adipose triglyceride lipase (ATGL/PNPLA2 and its co-activator comparative gene identification 58 (CGI-58/ABHD5. Ectopic expression of miR-124a in adipocytes leads to reduced lipolysis and increased cellular TG accumulation. This phenotype, however, can be rescued by overexpression of truncated Atgl lacking its 3'UTR, which harbors the identified miR-124a target site. In addition, we observe a strong negative correlation between miR-124a and Atgl expression in various murine tissues. Moreover, miR-124a regulates the expression of Atgl and Cgi-58 in murine white adipose tissue during fasting as well as the expression of Atgl in murine liver, during fasting and re-feeding. Together, these results point to an instrumental role of miR-124a in the regulation of TG catabolism. Therefore, we suggest that miR-124a may be involved in the regulation of several cellular and organismal metabolic parameters, including lipid storage and plasma FA concentration.

  8. Mycobacterium tuberculosis eis regulates autophagy, inflammation, and cell death through redox-dependent signaling.

    Directory of Open Access Journals (Sweden)

    Dong-Min Shin

    Full Text Available The "enhanced intracellular survival" (eis gene of Mycobacterium tuberculosis (Mtb is involved in the intracellular survival of M. smegmatis. However, its exact effects on host cell function remain elusive. We herein report that Mtb Eis plays essential roles in modulating macrophage autophagy, inflammatory responses, and cell death via a reactive oxygen species (ROS-dependent pathway. Macrophages infected with an Mtb eis-deletion mutant H37Rv (Mtb-Δeis displayed markedly increased accumulation of massive autophagic vacuoles and formation of autophagosomes in vitro and in vivo. Infection of macrophages with Mtb-Δeis increased the production of tumor necrosis factor-α and interleukin-6 over the levels produced by infection with wild-type or complemented strains. Elevated ROS generation in macrophages infected with Mtb-Δeis (for which NADPH oxidase and mitochondria were largely responsible rendered the cells highly sensitive to autophagy activation and cytokine production. Despite considerable activation of autophagy and proinflammatory responses, macrophages infected with Mtb-Δeis underwent caspase-independent cell death. This cell death was significantly inhibited by blockade of autophagy and c-Jun N-terminal kinase-ROS signaling, suggesting that excessive autophagy and oxidative stress are detrimental to cell survival. Finally, artificial over-expression of Eis or pretreatment with recombinant Eis abrogated production of both ROS and proinflammatory cytokines, which depends on the N-acetyltransferase domain of the Eis protein. Collectively, these data indicate that Mtb Eis suppresses host innate immune defenses by modulating autophagy, inflammation, and cell death in a redox-dependent manner.

  9. WT1 is involved in the Akt-JNK pathway dependent autophagy through directly regulating Gas1 expression in human osteosarcoma cells.

    Science.gov (United States)

    Mo, Hao; He, Juliang; Yuan, Zhenchao; Mo, Ligen; Wu, Zhenjie; Lin, Xiang; Liu, Bin; Guan, Jian

    2016-09-01

    Macroautophagy (herein termed autophagy) works as a protective mechanism in tumorigenesis and development under metabolic stress condition. Multitudes of genes have been found involved in this process during past decades. In the present study, we report that Wilm's tumor suppressor1 (WT1) is involved in autophagy in osteosarcoma (OS) cells. WT1, a transcription factor with multitude of target genes, expresses in a majority of cancer types. Though wide-ranging effect of WT1 is now well documented, the function of WT1 in tumors remains poorly defined. In this chapter, it is found that high expression of WT1 positively correlates with active autophagy in human osteosarcoma cells. And further study on cell signaling pathway illustrates that Akt/JNK pathway acts as a positive regulator of autophagy induced by WT1. Here, we present evidence that WT1 modulates Akt/JNK signaling pathway mediated autophagy by controlling the expression of growth arrest-specific 1 (Gas1). We show that WT1 is required for Gas1 transcription in osteosarcoma cells. And Gas1 is upregulated followed WT1 overexpression in a time-dependent manner. Loss of Gas1 results in a reduction of WT1-induced autophagy. PMID:27453337

  10. p53: The Janus of autophagy?

    OpenAIRE

    Levine, Beth; Abrams, John

    2008-01-01

    The autophagy pathway functions in adaptation to nutrient stress and tumour suppression. The p53 tumour suppressor, previously thought to positively regulate autophagy, may also inhibit it. This dual interplay between p53 and autophagy regulation is enigmatic, but may underlie key aspects of metabolism and cancer biology.

  11. MiR-200b regulates autophagy associated with chemoresistance in human lung adenocarcinoma.

    Science.gov (United States)

    Pan, Banzhou; Feng, Bing; Chen, Yitian; Huang, Guichun; Wang, Rui; Chen, Longbang; Song, Haizhu

    2015-10-20

    Chemoresistance remains a major clinical problem in combating human lung adenocarcinoma (LAD), and abnormal autophagy is closely associated with this phenomenon. In the present study, an inverse correlation between miR-200b and autophagy-associated gene 12 (ATG12) expressions was observed in docetaxel-resistant (SPC-A1/DTX and H1299/DTX) and sensitive (SPC-A1 and H1299) LAD cells as well as in tissue samples. Further study showed that miR-200b directly targeted ATG12 in LAD. Moreover, miR-200b-dependent ATG12 downregulation inhibited autophagy and enhanced the chemosensitivity of SPC-A1/DTX and H1299/DTX cells both in vivo and in vitro. LAD chemoresistance is therefore closely related to downregulation of miR-200b and the corresponding upregulation of ATG12. These results provide new evidence for the mechanisms governing the microRNA (miRNA)-ATG12 network and their possible contribution to autophagy modulation and LAD chemoresistance.

  12. miR-140-5p attenuates chemotherapeutic drug-induced cell death by regulating autophagy through inositol 1,4,5-trisphosphate kinase 2 (IP3k2) in human osteosarcoma cells

    Science.gov (United States)

    Wei, Renxiong; Cao, Gang; Deng, Zhouming; Su, Jiajia; Cai, Lin

    2016-01-01

    Acquisition of drug-resistant phenotypes is often associated with chemotherapy in osteosarcoma. A number of studies have demonstrated a critical role for autophagy in osteosarcoma development, therapy and drug resistance. However, the molecular mechanisms underlying the autophagy-mediated chemotherapy resistance of osteosarcoma cells remain largely unknown. In the present study, we determined the autophagy and microRNA-140 (miR-140-5p, miRBase ID: MIMAT0000431) expression induced by chemotherapeutic drugs in osteosarcoma cells. Then we determined the promotory role of miR-140-5p to the chemotherapy-induced autophagy. Our results demonstrated that miR-140-5p expression was highly induced during chemotherapy of osteosarcoma cells, and this was accompanied by up-regulated autophagy. The increased miR-140-5p expression levels up-regulated anticancer drug-induced autophagy in osteosarcoma cells and ameliorated the anticancer drug-induced cell proliferation and viability decrease. Importantly, miR-140-5p regulates this context-specific autophagy through its target, inositol 1,4,5-trisphosphate kinase 2 (IP3k2). Therefore, the results of the present study demonstrated that miR-140-5p mediated drug-resistance in osteosarcoma cells by inducing autophagy. The present study provides evidence of miRNA regulation of autophagy through modulation of IP3 signalling. The present study recognized a novel mechanism of chemoresistance in osteosarcoma cancers. PMID:27582507

  13. Autophagy contributes to regulation of nuclear dynamics during vegetative growth and hyphal fusion in Fusarium oxysporum.

    Science.gov (United States)

    Corral-Ramos, Cristina; Roca, M Gabriela; Di Pietro, Antonio; Roncero, M Isabel G; Ruiz-Roldán, Carmen

    2015-01-01

    In the fungal pathogen Fusarium oxysporum, vegetative hyphal fusion triggers nuclear mitotic division in the invading hypha followed by migration of a nucleus into the receptor hypha and degradation of the resident nucleus. Here we examined the role of autophagy in fusion-induced nuclear degradation. A search of the F. oxysporum genome database for autophagy pathway components identified putative orthologs of 16 core autophagy-related (ATG) genes in yeast, including the ubiquitin-like protein Atg8, which is required for the formation of autophagosomal membranes. F. oxysporum Foatg8Δ mutants were generated in a strain harboring H1-cherry fluorescent protein (ChFP)-labeled nuclei to facilitate analysis of nuclear dynamics. The Foatg8Δ mutants did not show MDC-positive staining in contrast to the wild type and the FoATG8-complemented (cFoATG8) strain, suggesting that FoAtg8 is required for autophagy in F. oxysporum. The Foatg8Δ strains displayed reduced rates of hyphal growth, conidiation, and fusion, and were significantly attenuated in virulence on tomato plants and in the nonvertebrate animal host Galleria mellonella. In contrast to wild-type hyphae, which are almost exclusively composed of uninucleated hyphal compartments, the hyphae of the Foatg8Δ mutants contained a significant fraction of hyphal compartments with 2 or more nuclei. The increase in the number of nuclei per hyphal compartment was particularly evident after hyphal fusion events. Time-lapse microscopy analyses revealed abnormal mitotic patterns during vegetative growth in the Foatg8Δ mutants. Our results suggest that autophagy mediates nuclear degradation after hyphal fusion and has a general function in the control of nuclear distribution in F. oxysporum.

  14. Up-regulation of mitochondrial activity and acquirement of brown adipose tissue-like property in the white adipose tissue of fsp27 deficient mice.

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    Shen Yon Toh

    Full Text Available Fsp27, a member of the Cide family proteins, was shown to localize to lipid droplet and promote lipid storage in adipocytes. We aimed to understand the biological role of Fsp27 in regulating adipose tissue differentiation, insulin sensitivity and energy balance. Fsp27(-/- mice and Fsp27/lep double deficient mice were generated and we examined the adiposity, whole body metabolism, BAT and WAT morphology, insulin sensitivity, mitochondrial activity, and gene expression changes in these mouse strains. Furthermore, we isolated mouse embryonic fibroblasts (MEFs from wildtype and Fsp27(-/- mice, followed by their differentiation into adipocytes in vitro. We found that Fsp27 is expressed in both brown adipose tissue (BAT and white adipose tissue (WAT and its levels were significantly elevated in the WAT and liver of leptin-deficient ob/ob mice. Fsp27(-/- mice had increased energy expenditure, lower levels of plasma triglycerides and free fatty acids. Furthermore, Fsp27(-/-and Fsp27/lep double-deficient mice are resistant to diet-induced obesity and display increased insulin sensitivity. Moreover, white adipocytes in Fsp27(-/- mice have reduced triglycerides accumulation and smaller lipid droplets, while levels of mitochondrial proteins, mitochondrial size and activity are dramatically increased. We further demonstrated that BAT-specific genes and key metabolic controlling factors such as FoxC2, PPAR and PGC1alpha were all markedly upregulated. In contrast, factors inhibiting BAT differentiation such as Rb, p107 and RIP140 were down-regulated in the WAT of Fsp27(-/- mice. Remarkably, Fsp27(-/- MEFs differentiated in vitro show many brown adipocyte characteristics in the presence of the thyroid hormone triiodothyronine (T3. Our data thus suggest that Fsp27 acts as a novel regulator in vivo to control WAT identity, mitochondrial activity and insulin sensitivity.

  15. Autophagy and cytokines.

    Science.gov (United States)

    Harris, James

    2011-11-01

    Autophagy is a highly conserved homoeostatic mechanism for the lysosomal degradation of cytosolic constituents, including long-lived macromolecules, organelles and intracellular pathogens. Autophagosomes are formed in response to a number of environmental stimuli, including amino acid deprivation, but also by both host- and pathogen-derived molecules, including toll-like receptor ligands and cytokines. In particular, IFN-γ, TNF-α, IL-1, IL-2, IL-6 and TGF-β have been shown to induce autophagy, while IL-4, IL-10 and IL-13 are inhibitory. Moreover, autophagy can itself regulate the production and secretion of cytokines, including IL-1, IL-18, TNF-α, and Type I IFN. This review discusses the potentially pivotal roles of autophagy in the regulation of inflammation and the coordination of innate and adaptive immune responses.

  16. MECHANISMS IN ENDOCRINOLOGY: Brown adipose tissue in humans: regulation and metabolic significance.

    Science.gov (United States)

    Thuzar, Moe; Ho, Ken K Y

    2016-07-01

    The recent discovery that functional brown adipose tissue (BAT) persists in adult humans has enkindled a renaissance in metabolic research, with a view of harnessing its thermogenic capacity to combat obesity. This review focuses on the advances in the regulation and the metabolic significance of BAT in humans. BAT activity in humans is stimulated by cold exposure and by several factors such as diet and metabolic hormones. BAT function is regulated at two levels: an acute process involving the stimulation of the intrinsic thermogenic activity of brown adipocytes and a chronic process of growth involving the proliferation of pre-existing brown adipocytes or differentiation to brown adipocytes of adipocytes from specific white adipose tissue depots. BAT activity is reduced in the obese, and its stimulation by cold exposure increases insulin sensitivity and reduces body fat. These observations provide strong evidence that BAT plays a significant role in energy balance in humans and has the potential to be harnessed as a therapeutic target for the management of obesity. PMID:27220620

  17. Yin and Yang of hypothalamic insulin and leptin signaling in regulating white adipose tissue metabolism.

    Science.gov (United States)

    Scherer, Thomas; Buettner, Christoph

    2011-09-01

    Fatty acids released from white adipose tissue (WAT) provide important energy substrates during fasting. However, uncontrolled fatty acid release from WAT during non-fasting states causes lipotoxicity and promotes inflammation and insulin resistance, which can lead to and worsen type 2 diabetes (DM2). WAT is also a source for insulin sensitizing fatty acids such as palmitoleate produced during de novo lipogenesis. Insulin and leptin are two major hormonal adiposity signals that control energy homeostasis through signaling in the central nervous system. Both hormones have been implicated to regulate both WAT lipolysis and de novo lipogenesis through the mediobasal hypothalamus (MBH) in an opposing fashion independent of their respective peripheral receptors. Here, we review the current literature on brain leptin and insulin action in regulating WAT metabolism and discuss potential mechanisms and neuro-anatomical substrates that could explain the opposing effects of central leptin and insulin. Finally, we discuss the role of impaired hypothalamic control of WAT metabolism in the pathogenesis of insulin resistance, metabolic inflexibility and type 2 diabetes. PMID:21713385

  18. Adipose triglyceride lipase regulates lipid metabolism in dairy goat mammary epithelial cells.

    Science.gov (United States)

    Li, Jun; Luo, Jun; Wang, Hui; Shi, Hengbo; Zhu, Jiangjiang; Sun, Yuting; Yu, Kang; Yao, Dawei

    2015-01-01

    Adipose triglyceride lipase (ATGL) catalyzes the initial step in the lipid lipolysis process, hydrolyzing triglyceride (TG) to produce diacylglycerol (DG) and free fatty acids (FFA). In addition, ATGL regulates lipid storage and release in adipocyte cells. However, its role in mammary gland tissue remains unclear. To assess the role of the ATGL gene in the goat mammary gland, this study analyzed the tissue distribution and expression of key genes together with lipid accumulation after knockdown of the ATGL gene. The mRNA of ATGL was highly expressed in subcutaneous adipose tissue, the lung and the mammary gland with a significant increase in expression during the lactation period compared with the dry period of the mammary gland. Knockdown of the ATGL gene in goat mammary epithelial cells (GMECs) using siRNA resulted in a significant decrease in both ATGL mRNA and protein levels. Silencing of the ATGL gene markedly increased lipid droplet accumulation and intracellular TG concentration (Pfat formation and secretion was down-regulated (PCD36 for fatty acid uptake (P<0.05). In conclusion, these data suggest that the ATGL gene plays an important role in triglyceride lipolysis in GMECs and provides the first experimental evidence that ATGL may be involved in lipid metabolism during lactation. PMID:25307872

  19. Global genomic profiling reveals an extensive p53-regulated autophagy program contributing to key p53 responses

    OpenAIRE

    Kenzelmann Broz, Daniela; Spano Mello, Stephano; Bieging, Kathryn T.; Jiang, Dadi; Rachel L Dusek; Brady, Colleen A.; Sidow, Arend; Attardi, Laura D.

    2013-01-01

    To gain new insights into p53 biology, Kenzelmann Broz et al. used high-throughput sequencing to analyze global p53 transcriptional networks in primary mouse embryo fibroblasts in response to DNA damage. This approach identified autophagy genes as direct p53 target genes. p53-induced autophagy was important for both p53-dependent apoptosis and transformation suppression by p53. These data highlight an intimate connection between p53 and autophagy and suggest that autophagy contributes to p53-...

  20. Oxidative stress, autophagy, epigenetic changes and regulation by miRNAs as potential therapeutic targets in osteoarthritis.

    Science.gov (United States)

    Portal-Núñez, Sergio; Esbrit, Pedro; Alcaraz, María José; Largo, Raquel

    2016-05-15

    Aging is a natural process characterized by the declining ability of the different organs and tissues to respond to stress, increasing homeostatic imbalance and risk of disease. Osteoarthritis (OA) is a multifactorial disease in which cartilage degradation is a central feature. Aging is the main risk factor for OA. In OA cartilage, a decrease in the number of chondrocytes and in their ability to regenerate the extracellular matrix and adequately respond to stress has been described. OA chondrocytes show a senescence secretory phenotype (SSP) consisting on the overproduction of cytokines (interleukins 1 and 6), growth factors (e.g., epidermal growth factor) and matrix metalloproteinases (MMP) (e.g., MMP-3, MMP-13). Reactive Oxygen Species (ROS) play a major role in the induction of the SSP. In chondrocytes, an increase in ROS production leads to hyper-peroxidation, protein carbonylation and DNA damage which alter chondrocyte function. ROS overproduction also induces changes in metabolic pathways such as PI3K-Akt and ERK. Autophagy is a key mechanism for maintaining cell homeostasis by adjusting cell metabolism to nutrient supply and removing damaged organelles. In cartilage, aging-related loss of autophagy leads to cell death and OA, while stimulation of autophagy exerts protective effects on cartilage deterioration. Aging also interferes with epigenetic mechanisms such as activity of histone acetylases that control the pattern of DNA methylation, and induces up- or down-regulation of microRNAs expression. A deeper knowledge of the mechanisms involved in chondrocyte aging could identify potential targets for the treatment of OA, a prevalent and therapeutic-orphan disease.

  1. The autophagy gene Wdr45/Wipi4 regulates learning and memory function and axonal homeostasis.

    Science.gov (United States)

    Zhao, Yan G; Sun, Le; Miao, Guangyan; Ji, Cuicui; Zhao, Hongyu; Sun, Huayu; Miao, Lin; Yoshii, Saori R; Mizushima, Noboru; Wang, Xiaoqun; Zhang, Hong

    2015-01-01

    WDR45/WIPI4, encoding a WD40 repeat-containing PtdIns(3)P binding protein, is essential for the basal autophagy pathway. Mutations in WDR45 cause the neurodegenerative disease β-propeller protein-associated neurodegeneration (BPAN), a subtype of NBIA. We generated CNS-specific Wdr45 knockout mice, which exhibit poor motor coordination, greatly impaired learning and memory, and extensive axon swelling with numerous axon spheroids. Autophagic flux is defective and SQSTM1 (sequestosome-1)/p62 and ubiquitin-positive protein aggregates accumulate in neurons and swollen axons. Nes-Wdr45(fl/Y) mice recapitulate some hallmarks of BPAN, including cognitive impairment and defective axonal homeostasis, providing a model for revealing the disease pathogenesis of BPAN and also for investigating the possible role of autophagy in axon maintenance.

  2. ALFY-Controlled DVL3 Autophagy Regulates Wnt Signaling, Determining Human Brain Size.

    Directory of Open Access Journals (Sweden)

    Rotem Kadir

    2016-03-01

    Full Text Available Primary microcephaly is a congenital neurodevelopmental disorder of reduced head circumference and brain volume, with fewer neurons in the cortex of the developing brain due to premature transition between symmetrical and asymmetrical cellular division of the neuronal stem cell layer during neurogenesis. We now show through linkage analysis and whole exome sequencing, that a dominant mutation in ALFY, encoding an autophagy scaffold protein, causes human primary microcephaly. We demonstrate the dominant effect of the mutation in drosophila: transgenic flies harboring the human mutant allele display small brain volume, recapitulating the disease phenotype. Moreover, eye-specific expression of human mutant ALFY causes rough eye phenotype. In molecular terms, we demonstrate that normally ALFY attenuates the canonical Wnt signaling pathway via autophagy-dependent removal specifically of aggregates of DVL3 and not of Dvl1 or Dvl2. Thus, autophagic attenuation of Wnt signaling through removal of Dvl3 aggregates by ALFY acts in determining human brain size.

  3. Molecular pathways regulating the formation of brown-like adipocytes in white adipose tissue.

    Science.gov (United States)

    Fu, Jianfei; Li, Zhen; Zhang, Huiqin; Mao, Yushan; Wang, Anshi; Wang, Xin; Zou, Zuquan; Zhang, Xiaohong

    2015-07-01

    Adipose tissue is functionally composed of brown adipose tissue and white adipose tissue. The unique thermogenic capacity of brown adipose tissue results from expression of uncoupling protein 1 in the mitochondrial inner membrane. On the basis of recent findings that adult humans have functionally active brown adipose tissue, it is now recognized as playing a much more important role in human metabolism than was previously thought. More importantly, brown-like adipocytes can be recruited in white adipose tissue upon environmental stimulation and pharmacologic treatment, and this change is associated with increased energy expenditure, contributing to a lean and healthy phenotype. Thus, the promotion of brown-like adipocyte development in white adipose tissue offers novel possibilities for the development of therapeutic strategies to combat obesity and related metabolic diseases. In this review, we summarize recent advances in understanding the molecular mechanisms involved in the recruitment of brown-like adipocyte in white adipose tissue.

  4. AUTOPHAGY AND IL-1 FAMILY CYTOKINES

    Directory of Open Access Journals (Sweden)

    James Harris

    2013-01-01

    Full Text Available Autophagy is an important intracellular homeostatic mechanism for the targeting of cytosolic constituents, including organelles, for lysosomal degradation. Autophagy plays roles in numerous physiological processes, include immune cell responses to endogenous and exogenous pathogenic stimuli. Moreover, autophagy has a potentially pivotal role in the regulation of inflammatory responses. In particular, autophagy regulates endogenous inflammasome activators, as well as inflammasome components and pro-IL-1β. This review focuses specifically on the role autophagy plays in regulating the production, processing and secretion of IL-1 family cytokines.

  5. Intra-articular delivery of sinomenium encapsulated by chitosan microspheres and photo-crosslinked GelMA hydrogel ameliorates osteoarthritis by effectively regulating autophagy.

    Science.gov (United States)

    Chen, Pengfei; Xia, Chen; Mei, Sheng; Wang, Jiying; Shan, Zhi; Lin, Xianfeng; Fan, Shunwu

    2016-03-01

    Reduced expression of autophagy regulators has been observed in pathological cartilage in humans and mice. The present study aimed to investigate the synergistic therapeutic effect of promotion of chondrocyte autophagy via exposure to sinomenium (SIN) encapsulated by chitosan microspheres (CM-SIN) and photo-crosslinked gelatin methacrylate (GelMA) hydrogel, with the goal of evaluating CM-SIN as a treatment for patients with osteoarthritis. First, we fabricated and characterized GelMA hydrogels and chitosan microspheres. Next, we measured the effect of SIN on cartilage matrix degradation induced by IL1-β in chondrocytes and an ex vivo model. SIN ameliorated the pathological changes induced by IL1-β at least partially through activation of autophagy. Moreover, we surgically induced osteoarthritis in mice, which were injected intra-articularly with CM-SIN and GelMA. Cartilage matrix degradation and chondrocyte autophagy were evaluated 4 and 8 weeks after surgery. Treatment with the combination of CM-SIN and GelMA retarded the progression of surgically induced OA. SIN ameliorated cartilage matrix degradation at least partially by inducing autophagy in vivo. Our results demonstrate that injection of the combination of GelMA hydrogel and CM-SIN could be a promising strategy for treating patients with osteoarthritis.

  6. Differential regulation of oxytocin receptor in various adipose tissue depots and skeletal muscle types in obese Zucker rats.

    Science.gov (United States)

    Gajdosechova, L; Krskova, K; Olszanecki, R; Zorad, S

    2015-07-01

    Multifunctional peptide oxytocin currently undergoes intensive research due to its proposed anti-obesity properties. Until now, little is known about regulation of oxytocin receptor in metabolically active tissues in obesity. The aim of the present study was to measure expression of oxytocin receptor upon obese phenotype with respect to the variety among adipose tissue and skeletal muscles with distinct anatomical localisation. Total homogenates were prepared from epididymal, retroperitoneal and inguinal adipose tissues as well as quadriceps and soleus muscle from lean and obese Zucker rats. Oxytocin receptor protein was determined by immunoblot. Interestingly, elevated oxytocin receptor was observed in epididymal adipose tissue of obese rats in contrast to its downregulation in subcutaneous and no change in retroperitoneal fat. In lean animals, oxytocin receptor protein was expressed at similar levels in all adipose depots. This uniformity was not observed in the case of skeletal muscle in which fibre type composition seems to be determinant of oxytocin receptor expression. Quadriceps muscle with the predominance of glycolytic fibres exhibits higher oxytocin receptor expression than almost exclusively oxidative soleus muscle. Oxytocin receptor protein levels were decreased in both skeletal muscles analysed upon obese phenotype. The present work demonstrates that even under identical endocrine circumstances, oxytocin receptor is differentially regulated in adipose tissue of obese rats depending on fat depot localisation. These results also imply which tissues may be preferentially targeted by oxytocin treatment in metabolic disease.

  7. Lithium and autophagy.

    Science.gov (United States)

    Motoi, Yumiko; Shimada, Kohei; Ishiguro, Koichi; Hattori, Nobutaka

    2014-06-18

    Lithium, a drug used to treat bipolar disorders, has a variety of neuroprotective mechanisms, including autophagy regulation, in various neuropsychiatric conditions. In neurodegenerative diseases, lithium enhances degradation of aggregate-prone proteins, including mutated huntingtin, phosphorylated tau, and α-synuclein, and causes damaged mitochondria to degrade, while in a mouse model of cerebral ischemia and Alzheimer's disease autophagy downregulation by lithium is observed. The signaling pathway of lithium as an autophagy enhancer might be associated with the mammalian target of rapamycin (mTOR)-independent pathway, which is involved in myo-inositol-1,4,5-trisphosphate (IP3) in Huntington's disease and Parkinson's disease. However, the mTOR-dependent pathway might be involved in inhibiting glycogen synthase kinase-3β (GSK3β) in other diseases. Lithium's autophagy-enhancing property may contribute to the therapeutic benefit of patients with neuropsychiatric disorders. PMID:24738557

  8. Autophagy and obesity%自噬和肥胖

    Institute of Scientific and Technical Information of China (English)

    张林; 胡茂清

    2015-01-01

    [Summary] Autophagy is an intracellular degradation process by which the damaged organelles and macromolecules are lysosomal dependently degraded by auto‐phagocyte under the control of autophagy‐related genes. The autophagy level in hypothalamus and adipose tissue changes in obese individuals.Autophagy participates in the regulation of food intake and energy balance ,and associates with adipocyte differentiation and adipogenesis. More and more attention has been paid to the relationship between autophagy and obesity w hich may guide the new research direction of pathogenesis study and therapy of obesity.%自噬是在相关基因的调控下,自噬细胞溶酶体依赖性的降解细胞内受损的细胞器及大分子物质的过程。肥胖个体下丘脑、脂肪组织自噬水平改变,自噬参与了下丘脑控制进食及能量平衡调节,并且与脂肪细胞的分化、脂肪形成有关。自噬与肥胖发生的关系日益受到重视,为肥胖的发病机制研究及治疗提供了新的方向。

  9. Research Progress of the Relationship between Autophagy and Lipid Deposition%自噬与脂质沉积关系的研究进展

    Institute of Scientific and Technical Information of China (English)

    刘燕

    2012-01-01

    Autophagy is a kind of degradation pathway for the breakdown of cytosolic macromolecules and organelles in eukaryotic cells. In non-adipose tissues, activation of autophagy can protect tissue from damage of lipid deposition,while inhibition of autophagy can prevent the development of obesity in adipose tissue. Autophagy is involved in the regulation of lipid deposition. There is a close relationship between autophagy disorders and lipid deposition-related diseases, such as fatty liver,type 2 diabetes mellitus( T2DM )and metabolic syndrome( MS ). Here is to make a review on the role of autophagy and lipid deposition.%自噬是真核细胞内一种大分子物质和细胞器降解途径,在非脂肪组织,激活自噬可保护组织免于脂质沉积的损伤,在脂肪组织,抑制自噬可阻止肥胖的发展.自噬参与细胞脂质沉积的调节,与脂肪肝、2型糖尿病(T2DM)、代谢综合征(MS)等脂质沉积相关疾病的发生、发展关系密切.现就自噬与脂质沉积的关系予以综述.

  10. Nutritional Status and Cardiac Autophagy

    Directory of Open Access Journals (Sweden)

    Jihyun Ahn

    2013-02-01

    Full Text Available Autophagy is necessary for the degradation of long-lasting proteins and nonfunctional organelles, and is activated to promote cellular survival. However, overactivation of autophagy may deplete essential molecules and organelles responsible for cellular survival. Lifelong calorie restriction by 40% has been shown to increase the cardiac expression of autophagic markers, which suggests that it may have a cardioprotective effect by decreasing oxidative damage brought on by aging and cardiovascular diseases. Although cardiac autophagy is critical to regulating protein quality and maintaining cellular function and survival, increased or excessive autophagy may have deleterious effects on the heart under some circumstances, including pressure overload-induced heart failure. The importance of autophagy has been shown in nutrient supply and preservation of energy in times of limitation, such as ischemia. Some studies have suggested that a transition from obesity to metabolic syndrome may involve progressive changes in myocardial inflammation, mitochondrial dysfunction, fibrosis, apoptosis, and myocardial autophagy.

  11. Autophagy in plants and phytopathogens.

    Science.gov (United States)

    Yoshimoto, Kohki; Takano, Yoshitaka; Sakai, Yasuyoshi

    2010-04-01

    Plants and plant-associated microorganisms including phytopathogens have to adapt to drastic changes in environmental conditions. Because of their immobility, plants must cope with various types of environmental stresses such as starvation, oxidative stress, drought stress, and invasion by phytopathogens during their differentiation, development, and aging processes. Here we briefly describe the early studies of plant autophagy, summarize recent studies on the molecular functions of ATG genes, and speculate on the role of autophagy in plants and phytopathogens. Autophagy regulates senescence and pathogen-induced cell death in plants, and autophagy and pexophagy play critical roles in differentiation and the invasion of host cells by phytopathogenic fungi. PMID:20079356

  12. G0/G1 switch gene-2 regulates human adipocyte lipolysis by affecting activity and localization of adipose triglyceride lipase

    NARCIS (Netherlands)

    Schweiger, M.; Paar, M.; Eder, C.; Brandis, J.; Moser, E.; Gorkiewisz, G.; Grond, S.; Radner, F.P.W.; Cerk, I.; Cornaciu, I.; Oberer, M.; Kersten, A.H.; Zechner, R.; Zimmermann, M.B.; Lass, A.

    2012-01-01

    The hydrolysis of triglycerides in adipocytes, termed lipolysis, provides free fatty acids as energy fuel. Murine lipolysis largely depends on the activity of adipose triglyceride lipase (ATGL)5, which is regulated by two proteins annotated as comparative gene identification-58 (CGI-58) and G0/G1 sw

  13. The autophagy gene Atg16l1 differentially regulates Treg and TH2 cells to control intestinal inflammation.

    Science.gov (United States)

    Kabat, Agnieszka M; Harrison, Oliver J; Riffelmacher, Thomas; Moghaddam, Amin E; Pearson, Claire F; Laing, Adam; Abeler-Dörner, Lucie; Forman, Simon P; Grencis, Richard K; Sattentau, Quentin; Simon, Anna Katharina; Pott, Johanna; Maloy, Kevin J

    2016-01-01

    A polymorphism in the autophagy gene Atg16l1 is associated with susceptibility to inflammatory bowel disease (IBD); however, it remains unclear how autophagy contributes to intestinal immune homeostasis. Here, we demonstrate that autophagy is essential for maintenance of balanced CD4(+) T cell responses in the intestine. Selective deletion of Atg16l1 in T cells in mice resulted in spontaneous intestinal inflammation that was characterized by aberrant type 2 responses to dietary and microbiota antigens, and by a loss of Foxp3(+) Treg cells. Specific ablation of Atg16l1 in Foxp3(+) Treg cells in mice demonstrated that autophagy directly promotes their survival and metabolic adaptation in the intestine. Moreover, we also identify an unexpected role for autophagy in directly limiting mucosal TH2 cell expansion. These findings provide new insights into the reciprocal control of distinct intestinal TH cell responses by autophagy, with important implications for understanding and treatment of chronic inflammatory disorders. PMID:26910010

  14. Autophagy in mammalian cells

    Institute of Scientific and Technical Information of China (English)

    Kadija; Abounit; Tiziano; M; Scarabelli; Roy; B; McCauley

    2012-01-01

    Autophagy is a regulated process for the degradation of cellular components that has been well conserved in eukaryotic cells. The discovery of autophagy-regulating proteins in yeast has been important in understanding this process. Although many parallels exist between fungi and mammals in the regulation and execution of autophagy, there are some important differences. The preautophagosomal structure found in yeast has not been identified in mammals, and it seems that there may be multiple origins for autophagosomes, including endoplasmic reticulum, plasma membrane and mitochondrial outer membrane. The maturation of the phagophore is largely dependent on 5’-AMP activated protein kinase and other factors that lead to the dephosphorylation of mammalian target of rapamycin. Once the process is initiated, the mammalian phagophore elongates and matures into an autophagosome by processes that are similar to those in yeast. Cargo selection is dependent on the ubiquitin conjugation of protein aggregates and organelles and recognition of these conjugates by autophagosomal receptors. Lysosomal degradation of cargo produces metabolites that can be recycled during stress. Autophagy is an impor-tant cellular safeguard during starvation in all eukaryotes; however, it may have more complicated, tissue specific roles in mammals. With certain exceptions, autophagy seems to be cytoprotective, and defects in the process have been associated with human disease.

  15. Differential Expression of Cell Cycle Regulators During Hyperplastic and Hypertrophic Growth of Broiler Subcutaneous Adipose Tissue.

    Science.gov (United States)

    Zhang, J; Suh, Y; Choi, Y M; Chen, P R; Davis, M E; Lee, K

    2015-10-01

    Hyperplastic growth and hypertrophic growth within adipose tissue is tightly associated with cell cycle activity. In this study, CCNG2 and CDKN2C were found to be correlated with cell cycle inhibition during fat cell differentiation, whereas CCND3, CCNA1, and ANAPC5 were positively associated with cell cycle activity during fat cell proliferation after selection based on GEO datasets available on the NCBI website. The findings were validated through comparison of expressions of these genes among different tissues/fractions in broiler chickens and time points during primary cell culture using quantitative real-time PCR. Development of broiler subcutaneous adipose tissue was investigated on embryonic days 15 and 17 and on post-hatch days 0, 5, 11, and 33 using H&E staining and PCNA immunostaining with DAPI counter stain. In addition, mRNA expressions of five cell cycle regulators as well as precursor cell and adipocyte markers were measured at those time points. The results suggest that cellular proliferation activity decreased as the fat pad grows, but a population of precursor cells seemed to be maintained until post-hatch day 5 despite increasing differentiation activity. Hypertrophic growth gradually intensified despite a slight cessation on post-hatch day 0 due to increased energy expenditure during hatching and delayed food access. From post-hatch day 5 to day 11, most of the precursor cells may become differentiated. After post-hatch day 11, hyperplastic growth seemed to slow, while hypertrophic growth may become dominant. This study provides further understanding about broiler fat tissue development which is imperative for effective control of fat deposition.

  16. Adrenergic regulation of cellular plasticity in brown, beige/brite and white adipose tissues.

    Science.gov (United States)

    Ramseyer, Vanesa D; Granneman, James G

    2016-01-01

    The discovery of brown adipose tissue in adult humans along with the recognition of adipocyte heterogeneity and plasticity of white fat depots has renewed the interest in targeting adipose tissue for therapeutic benefit. Adrenergic activation is a well-established means of recruiting catabolic adipocyte phenotypes in brown and white adipose tissues. In this article, we review mechanisms of brown adipocyte recruitment by the sympathetic nervous system and by direct β-adrenergic receptor activation. We highlight the distinct modes of brown adipocyte recruitment in brown, beige/brite, and white adipose tissues, UCP1-independent thermogenesis, and potential non-thermogenic, metabolically beneficial effects of brown adipocytes.

  17. Precision autophagy: Will the next wave of selective autophagy markers and specific autophagy inhibitors feed clinical pipelines?

    Science.gov (United States)

    Lebovitz, Chandra B; DeVorkin, Lindsay; Bosc, Damien; Rothe, Katharina; Singh, Jagbir; Bally, Marcel; Jiang, Xiaoyan; Young, Robert N; Lum, Julian J; Gorski, Sharon M

    2015-01-01

    Research presented at the Vancouver Autophagy Symposium (VAS) 2014 suggests that autophagy's influence on health and disease depends on tight regulation and precision targeting of substrates. Discussions recognized a pressing need for robust biomarkers that accurately assess the clinical utility of modulating autophagy in disease contexts. Biomarker discovery could flow from investigations of context-dependent triggers, sensors, and adaptors that tailor the autophagy machinery to achieve target specificity. In his keynote address, Dr. Vojo Deretic (University of New Mexico) described the discovery of a cargo receptor family that utilizes peptide motif-based cargo recognition, a mechanism that may be more precise than generic substrate tagging. The keynote by Dr. Alec Kimmelman (Harvard Medical School) emphasized that unbiased screens for novel selective autophagy factors may accelerate the development of autophagy-based therapies. Using a quantitative proteomics screen for de novo identification of autophagosome substrates in pancreatic cancer, Kimmelman's group discovered a new type of selective autophagy that regulates bioavailable iron. Additional presentations revealed novel autophagy regulators and receptors in metabolic diseases, proteinopathies, and cancer, and outlined the development of specific autophagy inhibitors and treatment regimens that combine autophagy modulation with anticancer therapies. VAS 2014 stimulated interdisciplinary discussions focused on the development of biomarkers, drugs, and preclinical models to facilitate clinical translation of key autophagy discoveries.

  18. Regulation of metabolic health and adipose tissue function by group 2 innate lymphoid cells.

    Science.gov (United States)

    Cautivo, Kelly M; Molofsky, Ari B

    2016-06-01

    Adipose tissue (AT) is home to an abundance of immune cells. With chronic obesity, inflammatory immune cells accumulate and promote insulin resistance and the progression to type 2 diabetes mellitus. In contrast, recent studies have highlighted the regulation and function of immune cells in lean, healthy AT, including those associated with type 2 or "allergic" immunity. Although traditionally activated by infection with multicellular helminthes, AT type 2 immunity is active independently of infection, and promotes tissue homeostasis, AT "browning," and systemic insulin sensitivity, protecting against obesity-induced metabolic dysfunction and type 2 diabetes mellitus. In particular, group 2 innate lymphoid cells (ILC2s) are integral regulators of AT type 2 immunity, producing the cytokines interleukin-5 and IL-13, promoting eosinophils and alternatively activated macrophages, and cooperating with and promoting AT regulatory T (Treg) cells. In this review, we focus on the recent developments in our understanding of group 2 innate lymphoid cell cells and type 2 immunity in AT metabolism and homeostasis. PMID:27120716

  19. The Antiaging Gene Klotho Regulates Proliferation and Differentiation of Adipose-Derived Stem Cells.

    Science.gov (United States)

    Fan, Jun; Sun, Zhongjie

    2016-06-01

    Klotho was originally discovered as an aging-suppressor gene. The purpose of this study was to investigate whether secreted Klotho (SKL) affects the proliferation and differentiation of adipose-derived stem cells (ADSCs). RT-PCR and Western blot analysis showed that short-form Klotho was expressed in mouse ADSCs. The Klotho gene mutation KL(-/-) significantly decreased proliferation of ADSCs and expression of pluripotent transcription factors (Nanog, Sox-2, and Oct-4) in mice. The adipogenic differentiation of ADSCs was also decreased in KL(-/-) mice. Incubation with Klotho-deficient medium decreased ADSC proliferation, pluripotent transcription factor levels, and adipogenic differentiation, which is similar to what was found in KL(-/-) mice. These results indicate that Klotho deficiency suppresses ADSC proliferation and differentiation. Interestingly, treatment with recombinant SKL protein rescued the Klotho deficiency-induced impairment in ADSC proliferation and adipogenic differentiation. SKL also regulated ADSCs' differentiation to other cell lineages (osteoblasts, myofibroblasts), indicating that SKL maintains stemness of ADSCs. It is intriguing that overexpression of SKL significantly increased PPAR-γ expression and lipid formation in ADSCs following adipogenic induction, indicating enhanced adipogenic differentiation. Overexpression of SKL inhibited expression of TGFβ1 and its downstream signaling mediator Smad2/3. This study demonstrates, for the first time, that SKL is essential to the maintenance of normal proliferation and differentiation in ADSCs. Klotho regulates adipogenic differentiation in ADSCs, likely via inhibition of TGFβ1 and activation of PPAR-γ. Stem Cells 2016;34:1615-1625. PMID:26865060

  20. Regulation of metabolic health and adipose tissue function by group 2 innate lymphoid cells.

    Science.gov (United States)

    Cautivo, Kelly M; Molofsky, Ari B

    2016-06-01

    Adipose tissue (AT) is home to an abundance of immune cells. With chronic obesity, inflammatory immune cells accumulate and promote insulin resistance and the progression to type 2 diabetes mellitus. In contrast, recent studies have highlighted the regulation and function of immune cells in lean, healthy AT, including those associated with type 2 or "allergic" immunity. Although traditionally activated by infection with multicellular helminthes, AT type 2 immunity is active independently of infection, and promotes tissue homeostasis, AT "browning," and systemic insulin sensitivity, protecting against obesity-induced metabolic dysfunction and type 2 diabetes mellitus. In particular, group 2 innate lymphoid cells (ILC2s) are integral regulators of AT type 2 immunity, producing the cytokines interleukin-5 and IL-13, promoting eosinophils and alternatively activated macrophages, and cooperating with and promoting AT regulatory T (Treg) cells. In this review, we focus on the recent developments in our understanding of group 2 innate lymphoid cell cells and type 2 immunity in AT metabolism and homeostasis.

  1. AKT3 controls mitochondrial biogenesis and autophagy via regulation of the major nuclear export protein CRM-1.

    Science.gov (United States)

    Corum, Daniel G; Tsichlis, Philip N; Muise-Helmericks, Robin C

    2014-01-01

    Our previous work has shown that Akt3 is required for mitochondrial biogenesis in primary human endothelial cells (ECs) and in Akt3-null mice; Akt3 affects subcellular localization of peroxisome proliferator-activated receptor γ coactivator-1 (PGC-1α), the master regulator of mitochondrial biogenesis. The purpose of this study is to determine the mechanism by which Akt3 controls the subcellular distribution of PGC-1α and to explore the effect on mitochondrial biogenesis and turnover during angiogenesis. Here we use standard biochemical analyses and Akt3-knockdown strategies to show that Akt3 controls the stabilization of chromosome maintenance region-1 (CRM-1), the major nuclear export receptor. Site-directed mutagenesis and association analyses show that PGC-1α nuclear export is CRM-1 dependent. Akt3 knockdown and CRM-1 overexpression cause 3-fold reductions in PGC-1α target gene expression, compared to control levels. Akt3 inhibition causes autophagy, as measured by autophagosome formation, in a CRM-1-dependent, Akt1/mTOR-independent pathway. In vivo, Akt3-null and heterozygous mice show dose-dependent decreases in angiogenesis compared to wild-type littermates (~5- and 2.5-fold decreases, respectively), as assessed by Matrigel plug assays. This correlates with an ~1.5-fold decrease in mitochondrial Cox IV expression. Our studies suggest that Akt3 is a regulator of mitochondrial dynamics in the vasculature via regulation of CRM-1-dependent nuclear export.

  2. TUSC5 regulates insulin-mediated adipose tissue glucose uptake by modulation of GLUT4 recycling

    Directory of Open Access Journals (Sweden)

    Nigel Beaton

    2015-11-01

    Conclusions: Collectively, these findings establish TUSC5 as an adipose tissue-specific protein that enables proper protein recycling, linking the ubiquitous vesicle traffic machinery with tissue-specific insulin-mediated glucose uptake into adipose tissue and the maintenance of a healthy metabolic phenotype in mice and humans.

  3. The symphony of autophagy and calcium signaling.

    Science.gov (United States)

    Yao, Zhiyuan; Klionsky, Daniel J

    2015-01-01

    Posttranslational regulation of macroautophagy (hereafter autophagy), including phosphorylating and dephosphorylating components of the autophagy-related (Atg) core machinery and the corresponding upstream transcriptional factors, is important for the precise modulation of autophagy levels. Several kinases that are involved in phosphorylating autophagy-related proteins have been identified in both yeast and mammalian cells. However, there has been much less research published with regard to the identification of the complementary phosphatases that function in autophagy. A recent study identified PPP3/calcineurin, a calcium-dependent phosphatase, as a regulator of autophagy, and demonstrated that one of the key targets of PPP3/calcineurin is TFEB, a master transcriptional factor that controls autophagy and lysosomal function in mammalian cells.

  4. Modulation of pathogen recognition by autophagy

    Directory of Open Access Journals (Sweden)

    Ji Eun eOh

    2012-03-01

    Full Text Available Autophagy is an ancient biological process for maintaining cellular homeostasis by degradation of long-lived cytosolic proteins and organelles. Recent studies demonstrated that autophagy is availed by immune cells to regulate innate immunity. On the one hand, cells exert direct effector function by degrading intracellular pathogens; on the other hand, autophagy modulates pathogen recognition and downstream signaling for innate immune responses. Pathogen recognition via pattern recognition receptors induces autophagy. The function of phagocytic cells is enhanced by recruitment of autophagy-related proteins. Moreover, autophagy acts as a delivery system for viral replication complexes to migrate to the endosomal compartments where virus sensing occurs. In another case, key molecules of the autophagic pathway have been found to negatively regulate immune signaling, thus preventing aberrant activation of cytokine production and consequent immune responses. In this review, we focus on the recent advances in the role of autophagy in pathogen recognition and modulation of innate immune responses.

  5. The cellular decision between apoptosis and autophagy

    Institute of Scientific and Technical Information of China (English)

    Yong-Jun Fan; Wei-Xing Zong

    2013-01-01

    Apoptosis and autophagy are important molecular processes that maintain organismal and cellular homeostasis,respectively.While apoptosis fulfills its role through dismantling damaged or unwanted cells,autophagy maintains cellular homeostasis through recycling selective intracellular organelles and molecules.Yet in some conditions,autophagy can lead to cell death.Apoptosis and autophagy can be stimulated by the same stresses.Emerging evidence indicates an interplay between the core proteins in both pathways,which underlies the molecular mechanism of the crosstalk between apoptosis and autophagy.This review summarizes recent literature on molecules that regulate both the apoptotic and autophagic processes.

  6. Hydrogen-rich saline mediates neuroprotection through the regulation of endoplasmic reticulum stress and autophagy under hypoxia-ischemia neonatal brain injury in mice.

    Science.gov (United States)

    Bai, Xuemei; Liu, Song; Yuan, Lin; Xie, Yunkai; Li, Tong; Wang, Lingxiao; Wang, Xueer; Zhang, Tiantian; Qin, Shucun; Song, Guohau; Ge, Li; Wang, Zhen

    2016-09-01

    Hydrogen as a new medical gas exerts organ-protective effects through regulating oxidative stress, inflammation and apoptosis. Multiple lines of evidence reveal the protective effects of hydrogen in various models of brain injury. However, the exact mechanism underlying this protective effect of hydrogen against hypoxic-ischemic brain damage (HIBD) is not fully understood. The present study was designed to investigate whether hydrogen-rich saline (HS) attenuates HIBD in neonatal mice and whether the observed protection is associated with reduced endoplasmic reticulum (ER) stress and regulated autophagy. The results showed that HS treatment significantly improved brain edema and decreased infarct volume. Furthermore, HS significantly attenuated HIBD-induced ER stress responses, including the decreased expression of glucose-regulated protein 78, C/EBP homologous protein, and down-regulated transcription factor. Additionally, we demonstrated that HS induced autophagy, including increased LC3B and Beclin-1 expression and decreased phosphorylation of mTOR and Stat3, as well as phosphorylation of ERK. Taken together, HS exerts neuroprotection against HIBD in neonatal mouse, mediated in part by reducing ER stress and increasing autophagy machinery. PMID:27317636

  7. Regulation and function of FTO mRNA expression in human skeletal muscle and subcutaneous adipose tissue

    DEFF Research Database (Denmark)

    Grunnet, Louise G; Nilsson, Emma; Ling, Charlotte;

    2009-01-01

    and adipose tissue, and their influence on in vivo glucose and fat metabolism. Research Design and Methods. The FTO rs9939609 polymorphism was genotyped in two twin cohorts: 1) 298 elderly twins aged 62-83 years with glucose tolerance ranging from normal to type 2 diabetes and 2) 196 young (25-32 years......Objective. Common variants in FTO (the fat-mass and obesity-associated gene) associate with obesity and type 2 diabetes. The regulation and biological function of FTO mRNA expression in target tissue is unknown. We investigated the genetic and non-genetic regulation of FTO mRNA in skeletal muscle......) and elderly (58-66 years) non-diabetic twins examined by a hyperinsulinemic euglycemic clamp including indirect calorimetry. FTO mRNA expression was determined in subcutaneous adipose tissue (n=226) and skeletal muscle biopsies (n=158). Results. Heritability of FTO expression in both tissues was low, and FTO...

  8. ACE2/Ang 1-7 axis: A critical regulator of epicardial adipose tissue inflammation and cardiac dysfunction in obesity.

    Science.gov (United States)

    Patel, Vaibhav B; Basu, Ratnadeep; Oudit, Gavin Y

    2016-01-01

    Obesity is characterized by an excessive fat accumulation in adipose tissues leading to weight gain and is increasing in prevalence and is strongly associated with metabolic and cardiovascular disorders. The renin-angiotensin system (RAS) has emerged as a key pathogenic mechanism for these disorders; activated RAS and angiotensin (Ang) II production results in worsening of cardiovascular diseases and angiotensin converting enzyme 2 (ACE2) negatively regulates RAS by metabolizing Ang II into Ang 1-7. ACE2 is expressed in the adipocytes and its expression is upregulated in response to high fat diet induced obesity in mice. Loss of ACE2 results in heart failure with preserved ejection fraction which is mediated in part by epicardial adipose tissue inflammation. Angiotensin 1-7 reduces the obesity associated cardiac dysfunction predominantly via its role in adiponectin expression and attenuation of epicardial adipose tissue inflammation. Human heart disease is also linked with inflammed epicardial adipose tissue. Here, we discuss the important interpretation of the novel of ACE2/Ang 1-7 pathway in obesity associated cardiac dysfunction. PMID:27617176

  9. Region-specific variation in the properties of skeletal adipocytes reveals regulated and constitutive marrow adipose tissues

    OpenAIRE

    Erica L. Scheller; Doucette, Casey R.; Learman, Brian S.; Cawthorn, William P; Khandaker, Shaima; Schell, Benjamin; Wu, Brent; Ding, Shi-Ying; Bredella, Miriam A.; Fazeli, Pouneh K.; Khoury, Basma; Jepsen, Karl J.; Pilch, Paul F.; Klibanski, Anne; ROSEN, CLIFFORD J

    2015-01-01

    Marrow adipose tissue (MAT) accumulates in diverse clinical conditions but remains poorly understood. Here we show region-specific variation in MAT adipocyte development, regulation, size, lipid composition, gene expression, and genetic determinants. Early MAT formation in mice is conserved, while later development is strain dependent. Proximal, but not distal, MAT is lost with 21-day cold exposure. Rat MAT adipocytes from distal sites have an increased proportion of monounsaturated fatty aci...

  10. Autonomic regulation of brown adipose tissue thermogenesis in health and disease: potential clinical applications for altering BAT thermogenesis

    OpenAIRE

    Domenico eTupone; Madden, Christopher J.; Morrison, Shaun F.

    2014-01-01

    From mouse to man, brown adipose tissue (BAT) is a significant source of thermogenesis contributing to the maintenance of the body temperature homeostasis during the challenge of low environmental temperature. In rodents, BAT thermogenesis also contributes to the febrile increase in core temperature during the immune response. BAT sympathetic nerve activity controlling BAT thermogenesis is regulated by CNS neural networks which respond reflexively to thermal afferent signals from cutaneous an...

  11. CD44 Plays a Critical Role in Regulating Diet-Induced Adipose Inflammation, Hepatic Steatosis, and Insulin Resistance

    OpenAIRE

    Hong Soon Kang; Grace Liao; DeGraff, Laura M.; Kevin Gerrish; Bortner, Carl D.; Stavros Garantziotis; Jetten, Anton M.

    2013-01-01

    CD44 is a multifunctional membrane receptor implicated in the regulation of several biological processes, including inflammation. CD44 expression is elevated in liver and white adipose tissue (WAT) during obesity suggesting a possible regulatory role for CD44 in metabolic syndrome. To study this hypothesis, we examined the effect of the loss of CD44 expression on the development of various features of metabolic syndrome using CD44 null mice. Our study demonstrates that CD44-deficient mice (CD...

  12. Regulation of gene expression by FSP27 in white and brown adipose tissue

    Directory of Open Access Journals (Sweden)

    Xue Bofu

    2010-07-01

    Full Text Available Abstract Background Brown and white adipose tissues (BAT and WAT play critical roles in controlling energy homeostasis and in the development of obesity and diabetes. The mouse Fat-Specific protein 27 (FSP27, a member of the cell death-inducing DFF45-like effector (CIDE family, is expressed in both BAT and WAT and is associated with lipid droplets. Over-expression of FSP27 promotes lipid storage, whereas FSP27 deficient mice have improved insulin sensitivity and are resistant to diet-induced obesity. In addition, FSP27-deficient white adipocytes have reduced lipid storage, smaller lipid droplets, increased mitochondrial activity and a higher expression of several BAT-selective genes. To elucidate the molecular mechanism by which FSP27 controls lipid storage and gene expression in WAT and BAT, we systematically analyzed the gene expression profile of FSP27-deficient WAT by microarray analysis and compared the expression levels of a specific set of genes in WAT and BAT by semi-quantitative real-time PCR analysis. Results BAT-selective genes were significantly up-regulated, whereas WAT-selective genes were down-regulated in the WAT of FSP27-deficient mice. The expression of the BAT-selective genes was also dramatically up-regulated in the WAT of leptin/FSP27 double deficient mice. In addition, the expression levels of genes involved in multiple metabolic pathways, including oxidative phosphorylation, the TCA cycle, fatty acid synthesis and fatty acid oxidation, were increased in the FSP27-deficient WAT. In contrast, the expression levels for genes involved in extracellular matrix remodeling, the classic complement pathway and TGF-β signaling were down-regulated in the FSP27-deficient WAT. Most importantly, the expression levels of regulatory factors that determine BAT identity, such as CEBPα/β, PRDM16 and major components of the cAMP pathway, were markedly up-regulated in the WAT of FSP27-deficient mice. The expression levels of these regulatory

  13. The role of STAT3 in autophagy.

    Science.gov (United States)

    You, Liangkun; Wang, Zhanggui; Li, Hongsen; Shou, Jiawei; Jing, Zhao; Xie, Jiansheng; Sui, Xinbing; Pan, Hongming; Han, Weidong

    2015-01-01

    Autophagy is an evolutionarily conserved process in eukaryotes that eliminates harmful components and maintains cellular homeostasis in response to a series of extracellular insults. However, these insults may trigger the downstream signaling of another prominent stress responsive pathway, the STAT3 signaling pathway, which has been implicated in multiple aspects of the autophagic process. Recent reports further indicate that different subcellular localization patterns of STAT3 affect autophagy in various ways. For example, nuclear STAT3 fine-tunes autophagy via the transcriptional regulation of several autophagy-related genes such as BCL2 family members, BECN1, PIK3C3, CTSB, CTSL, PIK3R1, HIF1A, BNIP3, and microRNAs with targets of autophagy modulators. Cytoplasmic STAT3 constitutively inhibits autophagy by sequestering EIF2AK2 as well as by interacting with other autophagy-related signaling molecules such as FOXO1 and FOXO3. Additionally, the mitochondrial translocation of STAT3 suppresses autophagy induced by oxidative stress and may effectively preserve mitochondria from being degraded by mitophagy. Understanding the role of STAT3 signaling in the regulation of autophagy may provide insight into the classic autophagy model and also into cancer therapy, especially for the emerging targeted therapy, because a series of targeted agents execute antitumor activities via blocking STAT3 signaling, which inevitably affects the autophagy pathway. Here, we review several of the representative studies and the current understanding in this particular field.

  14. Adipose triglyceride lipase is a TG hydrolase of the small intestine and regulates intestinal PPARα signaling.

    Science.gov (United States)

    Obrowsky, Sascha; Chandak, Prakash G; Patankar, Jay V; Povoden, Silvia; Schlager, Stefanie; Kershaw, Erin E; Bogner-Strauss, Juliane G; Hoefler, Gerald; Levak-Frank, Sanja; Kratky, Dagmar

    2013-02-01

    Adipose triglyceride lipase (ATGL) is the rate-limiting enzyme mediating triglyceride (TG) hydrolysis. The lack of ATGL results in TG accumulation in multiple tissues, underscoring the critical role of ATGL in maintaining lipid homeostasis. Recent evidence suggests that ATGL affects TG metabolism via activation of peroxisome proliferator-activated receptor α (PPARα). To investigate specific effects of intestinal ATGL on lipid metabolism we generated mice lacking ATGL exclusively in the intestine (ATGLiKO). We found decreased TG hydrolase activity and increased intracellular TG content in ATGLiKO small intestines. Intragastric administration of [(3)H]trioleate resulted in the accumulation of radioactive TG in the intestine, whereas absorption into the systemic circulation was unchanged. Intraperitoneally injected [(3)H]oleate also accumulated within TG in ATGLiKO intestines, indicating that ATGL mobilizes fatty acids from the systemic circulation absorbed by the basolateral side from the blood. Down-regulation of PPARα target genes suggested modulation of cholesterol absorption by intestinal ATGL. Accordingly, ATGL deficiency in the intestine resulted in delayed cholesterol absorption. Importantly, this study provides evidence that ATGL has no impact on intestinal TG absorption but hydrolyzes TGs taken up from the intestinal lumen and systemic circulation. Our data support the role of ATGL in modulating PPARα-dependent processes also in the small intestine.

  15. A Secreted Slit2 Fragment Regulates Adipose Tissue Thermogenesis and Metabolic Function.

    Science.gov (United States)

    Svensson, Katrin J; Long, Jonathan Z; Jedrychowski, Mark P; Cohen, Paul; Lo, James C; Serag, Sara; Kir, Serkan; Shinoda, Kosaku; Tartaglia, Julia A; Rao, Rajesh R; Chédotal, Alain; Kajimura, Shingo; Gygi, Steven P; Spiegelman, Bruce M

    2016-03-01

    Activation of brown and beige fat can reduce obesity and improve glucose homeostasis through nonshivering thermogenesis. Whether brown or beige fat also secretes paracrine or endocrine factors to promote and amplify adaptive thermogenesis is not fully explored. Here we identify Slit2, a 180 kDa member of the Slit extracellular protein family, as a PRDM16-regulated secreted factor from beige fat cells. In isolated cells and in mice, full-length Slit2 is cleaved to generate several smaller fragments, and we identify an active thermogenic moiety as the C-terminal fragment. This Slit2-C fragment of 50 kDa promotes adipose thermogenesis, augments energy expenditure, and improves glucose homeostasis in vivo. Mechanistically, Slit2 induces a robust activation of PKA signaling, which is required for its prothermogenic activity. Our findings establish a previously unknown peripheral role for Slit2 as a beige fat secreted factor that has therapeutic potential for the treatment of obesity and related metabolic disorders.

  16. Prohibitin/annexin 2 interaction regulates fatty acid transport in adipose tissue

    Science.gov (United States)

    Salameh, Ahmad; Daquinag, Alexes C.; Staquicini, Daniela I.; An, Zhiqiang; Hajjar, Katherine A.; Pasqualini, Renata; Arap, Wadih; Kolonin, Mikhail G.

    2016-01-01

    We have previously identified prohibitin (PHB) and annexin A2 (ANX2) as proteins interacting on the surface of vascular endothelial cells in white adipose tissue (WAT) of humans and mice. Here, we demonstrate that ANX2 and PHB also interact in adipocytes. Mice lacking ANX2 have normal WAT vascularization, adipogenesis, and glucose metabolism but display WAT hypotrophy due to reduced fatty acid uptake by WAT endothelium and adipocytes. By using cell culture systems in which ANX2/PHB binding is disrupted either genetically or through treatment with a blocking peptide, we show that fatty acid transport efficiency relies on this protein complex. We also provide evidence that the interaction between ANX2 and PHB mediates fatty acid transport from the endothelium into adipocytes. Moreover, we demonstrate that ANX2 and PHB form a complex with the fatty acid transporter CD36. Finally, we show that the colocalization of PHB and CD36 on adipocyte surface is induced by extracellular fatty acids. Together, our results suggest that an unrecognized biochemical interaction between ANX2 and PHB regulates CD36-mediated fatty acid transport in WAT, thus revealing a new potential pathway for intervention in metabolic diseases.

  17. Depletion of white adipose tissue in cancer cachexia syndrome is associated with inflammatory signaling and disrupted circadian regulation.

    Directory of Open Access Journals (Sweden)

    Maria Tsoli

    Full Text Available Involuntary weight loss in patients with cancer is the hallmark of cancer cachexia. The etiology of cachexia is multifactorial involving loss of skeletal muscle and adipose tissue associated with high systemic levels of acute phase proteins and inflammatory cytokines. While muscle wasting overtly impacts on cancer patient quality of life, loss of lipid depots represents a sustained energy imbalance. In this study fat depletion was examined in Colon-26 model of cancer cachexia, which is a widely used rodent model of this syndrome. We investigated diurnal expression of circadian rhythm regulators as well as key mediators of energy metabolism and cytokine signaling. Mice bearing the C26 tumour exhibited reduced adipose mass, elevated adipose tissue lipolysis and a 5-fold increase in plasma levels of free fatty acids. These changes were associated with activated IL-6 signaling in WAT through a 3-fold increase in phosphorylated STAT3 and high SOCS3 gene expression levels. In addition perturbations in circadian regulation of lipid metabolism were also observed. Lipid catabolism did not appear to be influenced by the classical PKA pathway activating the lipase HSL. ATGL protein levels were elevated 2-fold in cachectic mice while 4-fold increase phosphorylated ACC and a 2-fold decrease in phosphorylated 4EBP1 was observed indicating that lipid metabolism is modulated by the ATGL & AMPK/mTOR pathways. This study provides evidence for activation of cytokine signaling and concomitant alterations in circadian rhythm and regulators of lipid metabolism in WAT of cachectic animals.

  18. Translocator protein 18 kDa (TSPO is regulated in white and brown adipose tissue by obesity.

    Directory of Open Access Journals (Sweden)

    Misty M Thompson

    Full Text Available Translocator protein 18 kDa (TSPO is an outer-mitochondrial membrane transporter which has many functions including participation in the mitochondrial permeability transition pore, regulation of reactive oxygen species (ROS, production of cellular energy, and is the rate-limiting step in the uptake of cholesterol. TSPO expression is dysregulated during disease pathologies involving changes in tissue energy demands such as cancer, and is up-regulated in activated macrophages during the inflammatory response. Obesity is associated with decreased energy expenditure, mitochondrial dysfunction, and chronic low-grade inflammation which collectively contribute to the development of the Metabolic Syndrome. Therefore, we hypothesized that dysregulation of TSPO in adipose tissue may be a feature of disease pathology in obesity. Radioligand binding studies revealed a significant reduction in TSPO ligand binding sites in mitochondrial extracts from both white (WAT and brown adipose tissue (BAT in mouse models of obesity (diet-induced and genetic compared to control animals. We also confirmed a reduction in TSPO gene expression in whole tissue extracts from WAT and BAT. Immunohistochemistry in WAT confirmed TSPO expression in adipocytes but also revealed high-levels of TSPO expression in WAT macrophages in obese animals. No changes in TSPO expression were observed in WAT or BAT after a 17 hour fast or 4 hour cold exposure. Treatment of mice with the TSPO ligand PK11195 resulted in regulation of metabolic genes in WAT. Together, these results suggest a potential role for TSPO in mediating adipose tissue homeostasis.

  19. Sexual dimorphic regulation of body weight dynamics and adipose tissue lipolysis.

    Directory of Open Access Journals (Sweden)

    Verena Benz

    Full Text Available BACKGROUND: Successful reduction of body weight (BW is often followed by recidivism to obesity. BW-changes including BW-loss and -regain is associated with marked alterations in energy expenditure (EE and adipose tissue (AT metabolism. Since these processes are sex-specifically controlled, we investigated sexual dimorphisms in metabolic processes during BW-dynamics (gain-loss-regain. RESEARCH DESIGN: Obesity was induced in C57BL/6J male (m and female (f mice by 15 weeks high-fat diet (HFD feeding. Subsequently BW was reduced (-20% by caloric restriction (CR followed by adaptive feeding, and a regain-phase. Measurement of EE, body composition, blood/organ sampling were performed after each feeding period. Lipolysis was analyzed ex-vivo in gonadal AT. RESULTS: Male mice exhibited accelerated BW-gain compared to females (relative BW-gain m:140.5±3.2%; f:103.7±6.5%; p<0.001. In consonance, lean mass-specific EE was significantly higher in females compared to males during BW-gain. Under CR female mice reached their target-BW significantly faster than male mice (m:12.2 days; f:7.6 days; p<0.001 accompanied by a sustained sex-difference in EE. In addition, female mice predominantly downsized gonadal AT whereas the relation between gonadal and total body fat was not altered in males. Accordingly, only females exhibited an increased rate of forskolin-stimulated lipolysis in AT associated with significantly higher glycerol concentrations, lower RER-values, and increased AT expression of adipose triglyceride lipase (ATGL and hormone sensitive lipase (HSL. Analysis of AT lipolysis in estrogen receptor alpha (ERα-deficient mice revealed a reduced lipolytic rate in the absence of ERα exclusively in females. Finally, re-feeding caused BW-regain faster in males than in females. CONCLUSION: The present study shows sex-specific dynamics during BW-gain-loss-regain. Female mice responded to CR with an increase in lipolytic activity, and augmented lipid

  20. BAFF knockout improves systemic inflammation via regulating adipose tissue distribution in high-fat diet-induced obesity.

    Science.gov (United States)

    Kim, Do-Hwan; Do, Myoung-Sool

    2015-01-01

    Obesity is recognized as a chronic low-grade inflammatory state due to adipose tissue expansion being accompanied by an increase in the production of proinflammatory adipokines. Our group is the first to report that B-cell-activating factor (BAFF) is produced from adipocytes and functions as a proinflammatory adipokine. Here, we investigated how loss of BAFF influenced diet-induced obesity in mice by challenging BAFF(-/-) mice with a high-fat diet for 10 weeks. The results demonstrated that weight gain in BAFF(-/-) mice was >30% than in control mice, with a specific increase in the fat mass of the subcutaneous region rather than the abdominal region. Expression of lipogenic genes was examined by quantitative real-time PCR, and increased lipogenesis was observed in the subcutaneous adipose tissue (SAT), whereas lipogenesis in the epididymal adipose tissue (EAT) was reduced. A significant decrease in EAT mass resulted in the downregulation of inflammatory gene expression in EAT, and more importantly, overall levels of inflammatory cytokines in the circulation were reduced in obese BAFF(-/-) mice. We also observed that the macrophages recruited in the enlarged SAT were predominantly M2 macrophages. 3T3-L1 adipocytes were cultured with adipose tissue conditioned media (ATCM), demonstrating that EAT ATCM from BAFF(-/-) mice contains antilipogenic and anti-inflammatory properties. Taken together, BAFF(-/-) improved systemic inflammation by redistributing adipose tissue into subcutaneous regions. Understanding the mechanisms by which BAFF regulates obesity in a tissue-specific manner would provide therapeutic opportunities to target obesity-related chronic diseases. PMID:25591987

  1. Photoperiod regulates lean mass accretion, but not adiposity, in growing F344 rats fed a high fat diet.

    Directory of Open Access Journals (Sweden)

    Alexander W Ross

    Full Text Available In this study the effects of photoperiod and diet, and their interaction, were examined for their effects on growth and body composition in juvenile F344 rats over a 4-week period. On long (16L:8D, relative to short (8L:16D, photoperiod food intake and growth rate were increased, but percentage adiposity remained constant (ca 3-4%. On a high fat diet (HFD, containing 22.8% fat (45% energy as fat, food intake was reduced, but energy intake increased on both photoperiods. This led to a small increase in adiposity (up to 10% without overt change in body weight. These changes were also reflected in plasma leptin and lipid levels. Importantly while both lean and adipose tissue were strongly regulated by photoperiod on a chow diet, this regulation was lost for adipose, but not lean tissue, on HFD. This implies that a primary effect of photoperiod is the regulation of growth and lean mass accretion. Consistent with this both hypothalamic GHRH gene expression and serum IGF-1 levels were photoperiod dependent. As for other animals and humans, there was evidence of central hyposomatotropism in response to obesity, as GHRH gene expression was suppressed by the HFD. Gene expression of hypothalamic AgRP and CRH, but not NPY nor POMC, accorded with the energy balance status on long and short photoperiod. However, there was a general dissociation between plasma leptin levels and expression of these hypothalamic energy balance genes. Similarly there was no interaction between the HFD and photoperiod at the level of the genes involved in thyroid hormone metabolism (Dio2, Dio3, TSHβ or NMU, which are important mediators of the photoperiodic response. These data suggest that photoperiod and HFD influence body weight and body composition through independent mechanisms but in each case the role of the hypothalamic energy balance genes is not predictable based on their known function.

  2. The role of brown adipose tissue in temperature regulation. [of hibernating and hypothermic mammals

    Science.gov (United States)

    Smith, R. E.

    1973-01-01

    The thermogenetic capacities of brown adipose tissue were studied on marmots, rats and monkeys in response to cold exposure. All experiments indicated that the brown fat produced heat and slowed the cooling of tissues.

  3. Visfatin mRNA expression in human subcutaneous adipose tissue is regulated by exercise

    DEFF Research Database (Denmark)

    Frydelund-Larsen, Lone; Åkerström, Thorbjörn; Nielsen, Søren;

    2006-01-01

    Visfatin [pre-beta-cell colony-enhancing factor (PBEF)] is a novel adipokine that is produced by adipose tissue, skeletal muscle, and liver and has insulin-mimetic actions. Regular exercise enhances insulin sensitivity. In the present study, we therefore examined visfatin mRNA expression...... in abdominal subcutaneous adipose tissue and skeletal muscle biopsies obtained from healthy young men at time points 0, 3, 4.5, 6, 9, and 24 h in relation to either 3 h of ergometer cycle exercise at 60% of Vo(2 max) or rest. Adipose tissue visfatin mRNA expression increased threefold at the time points 3, 4.......5, and 6 h in response to exercise (n = 8) compared with preexercise samples and compared with the resting control group (n = 7, P = 0.001). Visfatin mRNA expression in skeletal muscle was not influenced by exercise. The exercise-induced increase in adipose tissue visfatin was, however, not accompanied...

  4. Early B-cell Factor 1 Regulates Adipocyte Morphology and Lipolysis in White Adipose Tissue

    OpenAIRE

    Gao, Hui; Mejhert, Niklas; Fretz, Jackie A.; Arner, Erik; Lorente-Cebrián, Silvia; Ehrlund, Anna; Dahlman-Wright, Karin; Gong, Xiaowei; Strömblad, Staffan; Douagi, Iyadh; Laurencikiene, Jurga; Dahlman, Ingrid; Daub, Carsten O.; Rydén, Mikael; Horowitz, Mark C.

    2014-01-01

    White adipose tissue (WAT) morphology characterized by hypertrophy (i.e. fewer but larger adipocytes) associates with increased adipose inflammation, lipolysis, insulin resistance and risk of diabetes. However, the causal relationships and the mechanisms controlling WAT morphology are unclear. Herein, we identified EBF1 as an adipocyte-expressed transcription factor with decreased expression/activity in WAT hypertrophy. In human adipocytes, the regulatory targets of EBF1 were enriched for gen...

  5. Autophagy and IL-1 family cytokines

    Directory of Open Access Journals (Sweden)

    James eHarris

    2013-04-01

    Full Text Available Autophagy is an important intracellular homeostatic mechanism for the targeting of cytosolic constituents, including organelles, for lysosomal degradation. Autophagy plays roles in numerous physiological processes, including immune cell responses to endogenous and exogenous pathogenic stimuli. Moreover, autophagy has a potentially pivotal role to play in the regulation of inflammatory responses. In particular, autophagy regulates endogenous inflammasome activators, as well as inflammasome components and pro-IL-1β. As a result, autophagy acts a key modulator of IL-1β and IL-18, as well as IL-1α, release. This review focuses specifically on the role autophagy plays in regulating the production, processing and secretion of IL-1 and IL-18 and the consequences of this important function.

  6. Autophagy and IL-1 Family Cytokines.

    Science.gov (United States)

    Harris, James

    2013-01-01

    Autophagy is an important intracellular homeostatic mechanism for the targeting of cytosolic constituents, including organelles, for lysosomal degradation. Autophagy plays roles in numerous physiological processes, including immune cell responses to endogenous and exogenous pathogenic stimuli. Moreover, autophagy has a potentially pivotal role to play in the regulation of inflammatory responses. In particular, autophagy regulates endogenous inflammasome activators, as well as inflammasome components and pro-IL-1β. As a result, autophagy acts a key modulator of IL-1β and IL-18, as well as IL-1α, release. This review focuses specifically on the role autophagy plays in regulating the production, processing, and secretion of IL-1 and IL-18 and the consequences of this important function.

  7. Developmental regulation of adipose tissue growth through hyperplasia and hypertrophy in the embryonic Leghorn and broiler.

    Science.gov (United States)

    Chen, Paula; Suh, Yeunsu; Choi, Young Min; Shin, Sangsu; Lee, Kichoon

    2014-07-01

    The United States is a world leader in poultry production, which is the reason why achieving better performance and muscle growth each year is a necessity. Reducing accretion of adipose tissue is another important factor for poultry producers because this allows more nutrients to be directed toward muscle growth, but the effect of embryonic adipose growth on posthatch development has not been fully understood. The purpose of this study was to investigate the total DNA mass, morphological characteristics, differentiation markers, and triglyceride breakdown factors of embryonic adipose tissue, and their relation to hyperplastic and hypertrophic growth within layers (Leghorn) and meat-type chickens (broilers). After embryonic day (E) 12, broiler weight was significantly higher than Leghorn, and this trend continued throughout the rest of incubation and posthatch (P Adipose triglyceride lipase was highly expressed at E20 and d 1 posthatch to mobilize triglyceride degradation for energy during hatching. Thus, embryonic chicken adipose tissue was found to develop by hyperplastic mechanisms followed by hypertrophy. At embryonic stages and early posthatch, layer- and meat-type chicken adipose growth does not differ, which suggests breed differences occur posthatch.

  8. Novel regulator of acylated ghrelin, CF801, reduces weight gain, rebound feeding after a fast, and adiposity in mice

    Directory of Open Access Journals (Sweden)

    Martin K Wellman

    2015-09-01

    Full Text Available Ghrelin is a 28 amino-acid hormonal peptide that is intimately related to the regulation of food intake and body weight. Once secreted, ghrelin binds to the growth hormone secretagogue receptor-1a (GHSR-1a, the only known receptor for ghrelin and is capable of activating a number of signaling cascades ultimately resulting in an increase in food intake and adiposity. Because ghrelin has been linked to overeating and the development of obesity, a number of pharmacological interventions have been generated in order to interfere with either the activation of ghrelin or interrupting ghrelin signaling as a means to reducing appetite and decrease weight gain. Here we present a novel peptide, CF801, capable of reducing circulating acylated ghrelin levels and subsequent body weight gain and adiposity. To this end, we show that IP administration of CF801 is sufficient to reduce circulating plasma acylated ghrelin levels. Acutely, intraperitoneal injections of CF801 resulted in decreased rebound feeding after an overnight fast. When delivered chronically decreased weight gain and adiposity without affecting caloric intake. CF801, however, did cause a change in diet preference, decreasing preference for a high fat diet and increasing preference for regular chow diet. Given the complexity of ghrelin receptor function, we propose that CF801 along with other compounds that regulate ghrelin secretion may prove to be a beneficial tool in the study of the ghrelin system, and potential targets for ghrelin based obesity treatments without altering the function of ghrelin receptors.

  9. Functional Interactions between 17β-Estradiol and Progesterone Regulate Autophagy during Acini Formation by Bovine Mammary Epithelial Cells in 3D Cultures

    Directory of Open Access Journals (Sweden)

    Katarzyna Zielniok

    2014-01-01

    Full Text Available Mammary gland epithelium forms a network of ducts and alveolar units under control of ovarian hormones: 17-beta-estradiol (E2 and progesterone (P4. Mammary epithelial cells (MECs cultured on reconstituted basement membrane (rBM form three-dimensional (3D acini composed of polarized monolayers surrounding a lumen. Using the 3D culture of BME-UV1 bovine MECs we previously demonstrated that autophagy was induced in the centrally located cells of developing spheroids, and sex steroids increased this process. In the present study we showed that E2 and P4 enhanced the expression of ATG3, ATG5, and BECN1 genes during acini formation, and this effect was accelerated in the presence of both hormones together. The stimulatory action of E2 and P4 was also reflected by increased levels of Atg5, Atg3, and LC3-II proteins. Additionally, the activity of kinases involved in autophagy regulation, Akt, ERK, AMPK, and mTOR, was examined. E2 + P4 slightly increased the level of phosphorylated AMPK but diminished phosphorylated Akt and mTOR on day 9 of 3D culture. Thus, the synergistic actions of E2 and P4 accelerate the development of bovine mammary acini, which may be connected with stimulation of ATGs expression, as well as regulation of signaling pathways (PI3K/Akt/mTOR; AMPK/mTOR involved in autophagy induction.

  10. Hsp90 regulates processing of NF-κB2 p100 involving protection of NF-κB-inducing kinase (NIK) from autophagy-mediated degradation

    Institute of Scientific and Technical Information of China (English)

    Guoliang Qing; Pengrong Yan; Zhaoxia Qu; Hudan Liu; Gutian Xiao

    2007-01-01

    NF-κB-inducing kinase (NIK) is required for NF-κB activation based on the processing of NF-κB2 p100. Here we report a novel mechanism of NIK regulation involving the chaperone 90 kDa heat shock protein (Hsp90) and autophagy.Functional inhibition of lisp90 by the anti-tumor agent geldanamycin (GA) efficiently disrupts its interaction with NIK,resulting in NIK degradation and subsequent blockage of p100 processing. Surprisingly, GA-induced NIK degradation is mediated by autophagy, but largely independent of the ubiquitin-proteasome system. Hsp90 seems to be specifically involved in the folding/stabilization of NIK protein, because GA inhibition does not affect NIK mRNA transcription and translation. Furthermore, Hsp90 is not required for NIK-mediated recruitment of the α subunit of IκB kinase to p100, a key step in induction of p100 processing. These findings define an alternative mechanism for Hsp90 client degradation and identify a novel function of autophagy in NF-κB regulation. These findings also suggest a new therapeutic strategy for diseases associated with p100 processing.

  11. Modulation of inflammation by autophagy: consequences for Crohn's disease.

    NARCIS (Netherlands)

    Plantinga, T.S.; Joosten, L.A.B.; Meer, J.W.M. van der; Netea, M.G.

    2012-01-01

    Autophagy, the cellular machinery for targeting intracellular components for lysosomal degradation, is critically involved in the host defence to pathogenic microorganisms. Recent studies have unveiled several aspects of the immune response that are regulated by autophagy, including antigen presenta

  12. Metabolic reprogramming through fatty acid transport protein 1 (FATP1 regulates macrophage inflammatory potential and adipose inflammation

    Directory of Open Access Journals (Sweden)

    Amy R. Johnson

    2016-07-01

    Conclusion: Our findings provide evidence that FATP1 is a novel regulator of MΦ activation through control of substrate metabolism. Absence of FATP1 exacerbated pro-inflammatory activation in vitro and increased local and systemic components of the metabolic syndrome in HFD-fed Fatp1B−/− mice. In contrast, gain of FATP1 activity in MΦs suggested that Fatp1-mediated activation of fatty acids, substrate switch to glucose, oxidative stress, and lipid mediator synthesis are potential mechanisms. We demonstrate for the first time that FATP1 provides a unique mechanism by which the inflammatory tone of adipose and systemic metabolism may be regulated.

  13. Antioxidant catalase rescues against high fat diet-induced cardiac dysfunction via an IKKβ-AMPK-dependent regulation of autophagy.

    Science.gov (United States)

    Liang, Lei; Shou, Xi-Ling; Zhao, Hai-Kang; Ren, Gu-Qun; Wang, Jian-Bang; Wang, Xi-Hui; Ai, Wen-Ting; Maris, Jackie R; Hueckstaedt, Lindsay K; Ma, Ai-Qun; Zhang, Yingmei

    2015-02-01

    Autophagy, a conservative degradation process for long-lived and damaged proteins, participates in a variety of biological processes including obesity. However, the precise mechanism of action behind obesity-induced changes in autophagy still remains elusive. This study was designed to examine the role of the antioxidant catalase in high fat diet-induced changes in cardiac geometry and function as well as the underlying mechanism of action involved with a focus on autophagy. Wild-type (WT) and transgenic mice with cardiac overexpression of catalase were fed low or high fat diet for 20 weeks prior to assessment of myocardial geometry and function. High fat diet intake triggered obesity, hyperinsulinemia, and hypertriglyceridemia, the effects of which were unaffected by catalase transgene. Myocardial geometry and function were compromised with fat diet intake as manifested by cardiac hypertrophy, enlarged left ventricular end systolic and diastolic diameters, fractional shortening, cardiomyocyte contractile capacity and intracellular Ca²⁺ mishandling, the effects of which were ameliorated by catalase. High fat diet intake promoted reactive oxygen species production and suppressed autophagy in the heart, the effects of which were attenuated by catalase. High fat diet intake dampened phosphorylation of inhibitor kappa B kinase β(IKKβ), AMP-activated protein kinase (AMPK) and tuberous sclerosis 2 (TSC2) while promoting phosphorylation of mTOR, the effects of which were ablated by catalase. In vitro study revealed that palmitic acid compromised cardiomyocyte autophagy and contractile function in a manner reminiscent of fat diet intake, the effect of which was significantly alleviated by inhibition of IKKβ, activation of AMPK and induction of autophagy. Taken together, our data revealed that the antioxidant catalase counteracts against high fat diet-induced cardiac geometric and functional anomalies possibly via an IKKβ-AMPK-dependent restoration of myocardial

  14. Activation of the MAPK11/12/13/14 (p38 MAPK) pathway regulates the transcription of autophagy genes in response to oxidative stress induced by a novel copper complex in HeLa cells.

    Science.gov (United States)

    Zhong, Wu; Zhu, Haichuan; Sheng, Fugeng; Tian, Yonglu; Zhou, Jun; Chen, Yingyu; Li, Song; Lin, Jian

    2014-07-01

    Transition metal copper (Cu) can exist in oxidized or reduced states in cells, leading to cytotoxicity in cancer cells through oxidative stress. Recently, copper complexes are emerging as a new class of anticancer compounds. Here, we report that a novel anticancer copper complex (HYF127c/Cu) induces oxidative stress-dependent cell death in cancer cells. Further, transcriptional analysis revealed that oxidative stress elicits broad transcriptional changes of genes, in which autophagy-related genes are significantly changed in HYF127c/Cu-treated cells. Consistently, autophagy was induced in HYF127c/Cu-treated cells and inhibitors of autophagy promoted cell death induced by HYF127c/Cu. Further analysis identified that the MAPK11/12/13/14 (formerly known as p38 MAPK) pathway was also activated in HYF127c/Cu-treated cells. Meanwhile, the MAPK11/12/13/14 inhibitor SB203580 downregulated autophagy by inhibiting the transcription of the autophagy genes MAP1LC3B, BAG3, and HSPA1A, and promoted HYF127c/Cu-induced cell death. These data suggest that copper-induced oxidative stress will induce protective autophagy through transcriptional regulation of autophagy genes by activation of the MAPK11/12/13/14 pathway in HeLa cells.

  15. Taxol-induced unfolded protein response activation in breast cancer cells exposed to hypoxia: ATF4 activation regulates autophagy and inhibits apoptosis.

    Science.gov (United States)

    Notte, Annick; Rebucci, Magali; Fransolet, Maude; Roegiers, Edith; Genin, Marie; Tellier, Celine; Watillon, Kassandra; Fattaccioli, Antoine; Arnould, Thierry; Michiels, Carine

    2015-05-01

    Understanding the mechanisms responsible for the resistance against chemotherapy-induced cell death is still of great interest since the number of patients with cancer increases and relapse is commonly observed. Indeed, the development of hypoxic regions as well as UPR (unfolded protein response) activation is known to promote cancer cell adaptive responses to the stressful tumor microenvironment and resistance against anticancer therapies. Therefore, the impact of UPR combined to hypoxia on autophagy and apoptosis activation during taxol exposure was investigated in MDA-MB-231 and T47D breast cancer cells. The results showed that taxol rapidly induced UPR activation and that hypoxia modulated taxol-induced UPR activation differently according to the different UPR pathways (PERK, ATF6, and IRE1α). The putative involvement of these signaling pathways in autophagy or in apoptosis regulation in response to taxol exposure was investigated. However, while no link between the activation of these three ER stress sensors and autophagy or apoptosis regulation could be evidenced, results showed that ATF4 activation, which occurs independently of UPR activation, was involved in taxol-induced autophagy completion. In addition, an ATF4-dependent mechanism leading to cancer cell adaptation and resistance against taxol-induced cell death was evidenced. Finally, our results demonstrate that expression of ATF4, in association with hypoxia-induced genes, can be used as a biomarker of a poor prognosis for human breast cancer patients supporting the conclusion that ATF4 might play an important role in adaptation and resistance of breast cancer cells to chemotherapy in hypoxic tumors.

  16. Ghrelin Attenuates Liver Fibrosis through Regulation of TGF-β1 Expression and Autophagy

    Directory of Open Access Journals (Sweden)

    Yuqing Mao

    2015-09-01

    and maintaining the balance between MMP2 and TIMP1. Our results demonstrated that ghrelin attenuates liver fibrosis via inhibition of the TGF-β1/Smad3 and NF-κB signaling pathways, as well as autophagy suppression.

  17. Telmisartan attenuates the inflamed mesenteric adipose tissue in spontaneous colitis by mechanisms involving regulation of neurotensin/microRNA-155 pathway.

    Science.gov (United States)

    Li, Yi; Zuo, Lugen; Zhu, Weiming; Gong, Jianfeng; Zhang, Wei; Guo, Zhen; Gu, Lili; Li, Ning; Li, Jieshou

    2015-02-15

    Mesenteric adipose tissue hypertrophy is unique to Crohn's disease while the molecular basis of the crosstalk between MAT and the intestinal inflammation is largely unknown. Telmisartan is an angiotensin II type 1 receptor blocker and a peroxisome proliferator-activated receptor-receptor-γ agonist which has beneficial effects on fat distribution and pro-inflammatory adipokine expression. We evaluated the effect of telmisartan upon mesenteric adipose tissue alterations and inflammatory features in IL-10(-)/(-) mice. We found that treatment with telmisartan significantly ameliorated the severity of colitis in IL-10(-)/(-) mice. Additionally, administration of telmisartan was associated with restoration of mesenteric adipose tissue adipocyte morphology and the expression of adipokines. Furthermore, telmisartan treatment suppressed the neurotensin/microRNA-155 pathway in mesenteric adipose tissue from spontaneous colitis which was confirmed by an in vitro study using cultured mesenteric adipose tissue from Crohn's disease patients. Administration of telmisartan showed promising results in spontaneous colitis which was associated with the attenuated mesenteric adipose tissue alteration which at least in part, was associated with its activity in the regulation of the neurotensin/microRNA-155 pathway. These results support the hypothesis that regulating the abnormal immune response in adipose tissue is an important target for the treatment of Crohn's disease. PMID:25576685

  18. Autophagy is involved in regulating the immune response of dendritic cells to influenza A (H1N1) pdm09 infection.

    Science.gov (United States)

    Zang, Farong; Chen, Yinghu; Lin, Zhendong; Cai, Zhijian; Yu, Lei; Xu, Feng; Wang, Jiaoli; Zhu, Weiguo; Lu, Huoquan

    2016-05-01

    Autophagy can mediate antiviral immunity. However, it remains unknown whether autophagy regulates the immune response of dendritic cells (DCs) to influenza A (H1N1) pdm09 infection. In this study, we found that infection with the H1N1 virus induced DC autophagy in an endocytosis-dependent manner. Compared with autophagy-deficient Beclin-1(+/-) mice, we found that bone-marrow-derived DCs from wild-type mice (WT BMDCs) presented a more mature phenotype on H1N1 infection. Wild-type BMDCs secreted higher levels of interleukin-6 (IL-6), tumour necrosis factor- α (TNF-α), interferon-β (IFN-β), IL-12p70 and IFN-γ than did Beclin-1(+/-) BMDCs. In contrast to Beclin-1(+/-) BMDCs, H1N1-infected WT BMDCs exhibited increased activation of extracellular signal-regulated kinase, Jun N-terminal kinase, p38, and nuclear factor-κB as well as IFN regulatory factor 7 nuclear translocation. Blockade of autophagosomal and lysosomal fusion by bafilomycin A1 decreased the co-localization of H1N1 viruses, autophagosomes and lysosomes as well as the secretion of IL-6, TNF-α and IFN-β in H1N1-infected BMDCs. In contrast to Beclin-1(+/-) BMDCs, H1N1-infected WT BMDCs were more efficient in inducing allogeneic CD4(+) T-cell proliferation and driving T helper type 1, 2 and 17 cell differentiation while inhibiting CD4(+) Foxp3(+) regulatory T-cell differentiation. Moreover, WT BMDCs were more efficient at cross-presenting the ovalbumin antigen to CD8(+) T cells. We consistently found that Beclin-1(+/-) BMDCs were inferior in their inhibition of H1N1 virus replication and their induction of H1N1-specific CD4(+) and CD8(+) T-cell responses, which produced lower levels of IL-6, TNF-α and IFN-β in vivo. Our data indicate that autophagy is important in the regulation of the DC immune response to H1N1 infection, thereby extending our understanding of host immune responses to the virus.

  19. Central and peripheral mechanisms of the NPY system in the regulation of bone and adipose tissue.

    Science.gov (United States)

    Shi, Yan-Chuan; Baldock, Paul A

    2012-02-01

    Skeletal research is currently undergoing a period of marked expansion. The boundaries of "bone" research are being re-evaluated and with this, a growing recognition of a more complex and interconnected biology than previously considered. One aspect that has become the focus of particular attention is the relationship between bone and fat homeostasis. Evidence from a number of avenues indicates that bone and adipose regulation are both related and interdependent. This review examines the neuropeptide Y (NPY) system, known to exert powerful control over both bone and fat tissue. The actions of this system are characterized by signaling both within specific nuclei of the hypothalamus and also the target tissues, mediated predominantly through two G-protein coupled receptors (Y1 and Y2). In bone tissue, elevated NPY levels act consistently to repress osteoblast activity. Moreover, both central Y2 receptor and osteoblastic Y1 receptor signaling act similarly to repress bone formation. Conversely, loss of NPY expression or receptor signaling induces increased osteoblast activity and bone mass in both cortical and cancellous envelopes. In fat tissue, NPY action is more complex. Energy homeostasis is powerfully altered by elevations in hypothalamic NPY, resulting in increases in fat accretion and body-wide energy conservation, through the action of locally expressed Y1 receptors, while local Y2 receptors act to inhibit NPY-ergic tone. Loss of central NPY expression has a markedly reduced effect, consistent with a physiological drive to promote fat accretion. In fat tissue, NPY and Y1 receptors act to promote lipogenesis, consistent with their roles in the brain. Y2 receptors expressed in adipocytes also act in this manner, showing an opposing action to their role in the hypothalamus. While direct investigation of these processes has yet to be completed, these responses appear to be interrelated to some degree. The starvation-based signal of elevated central NPY inducing

  20. Autophagy mitigates metabolic stress and genome damage in mammary tumorigenesis

    Science.gov (United States)

    Karantza-Wadsworth, Vassiliki; Patel, Shyam; Kravchuk, Olga; Chen, Guanghua; Mathew, Robin; Jin, Shengkan; White, Eileen

    2007-01-01

    Autophagy is a catabolic process involving self-digestion of cellular organelles during starvation as a means of cell survival; however, if it proceeds to completion, autophagy can lead to cell death. Autophagy is also a haploinsufficient tumor suppressor mechanism for mammary tumorigenesis, as the essential autophagy regulator beclin1 is monoallelically deleted in breast carcinomas. However, the mechanism by which autophagy suppresses breast cancer remains elusive. Here we show that allelic loss of beclin1 and defective autophagy sensitized mammary epithelial cells to metabolic stress and accelerated lumen formation in mammary acini. Autophagy defects also activated the DNA damage response in vitro and in mammary tumors in vivo, promoted gene amplification, and synergized with defective apoptosis to promote mammary tumorigenesis. Therefore, we propose that autophagy limits metabolic stress to protect the genome, and that defective autophagy increases DNA damage and genomic instability that ultimately facilitate breast cancer progression. PMID:17606641

  1. Oxidative stress-induced autophagy: Role in pulmonary toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Malaviya, Rama [Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854 (United States); Laskin, Jeffrey D. [Department of Environmental and Occupational Medicine, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ 08854 (United States); Laskin, Debra L., E-mail: laskin@eohsi.rutgers.edu [Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854 (United States)

    2014-03-01

    Autophagy is an evolutionarily conserved catabolic process important in regulating the turnover of essential proteins and in elimination of damaged organelles and protein aggregates. Autophagy is observed in the lung in response to oxidative stress generated as a consequence of exposure to environmental toxicants. Whether autophagy plays role in promoting cell survival or cytotoxicity is unclear. In this article recent findings on oxidative stress-induced autophagy in the lung are reviewed; potential mechanisms initiating autophagy are also discussed. A better understanding of autophagy and its role in pulmonary toxicity may lead to the development of new strategies to treat lung injury associated with oxidative stress. - Highlights: • Exposure to pulmonary toxicants is associated with oxidative stress. • Oxidative stress is known to induce autophagy. • Autophagy is upregulated in the lung following exposure to pulmonary toxicants. • Autophagy may be protective or pathogenic.

  2. Regulation of Lipolysis and Adipose Tissue Signaling during Acute Endotoxin-Induced Inflammation

    DEFF Research Database (Denmark)

    Rittig, Nikolaj; Bach, Ermina; Thomsen, Henrik Holm;

    2016-01-01

    = 0.001) compared with Placebo. These effects were associated with increased phosphorylation of hormone sensitive lipase (pHSL) at ser650 in adipose tissue (p = 0.03), a trend towards elevated pHSL at ser552 (p = 0.09) and cAMP-dependent protein kinase A (PKA) phosphorylation of perilipin 1 (PLIN1) (p...... lipolysis in adipose tissue and is associated with increased pHSL and signs of increased PLIN1 phosphorylation combined with a trend toward decreased insulin signaling. The combination of these mechanisms appear to be the driving forces behind the increased lipolysis observed in the early stages of acute...

  3. Autophagy gets in on the regulatory act

    Institute of Scientific and Technical Information of China (English)

    Steven K. Backues; Daniel J. Klionsky

    2011-01-01

    Autophagy down-regulates the Wnt signal transduction pathway via targeted degradation of a key signaling protein. This may provide an explanation for autophagy's role in tumor suppression.%@@ The eukaryotic cell has at its disposal two primary methods for getting rid of unwanted proteins: the proteasome and autophagy.The proteasome is a large protein complex comprising regulatory and proteolytic subunits whose core function is the degradation of damaged or misfolded proteins.

  4. The Ca{sup 2+} channel TRPML3 specifically interacts with the mammalian ATG8 homologue GATE16 to regulate autophagy

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Suzy; Kim, Hyun Jin, E-mail: kimhyunjin@skku.edu

    2014-01-03

    Highlights: •Split-ubiquitin MY2H screen identified GATE16 as an interacting protein of TRPML3. •TRPML3 specifically binds to a mammalian ATG8 homologue GATE16, not to LC3B. •The interaction of TRPML3 with GATE16 facilitates autophagosome formation. •GATE16 is expressed in both autophagosome and extra-autophagosomal compartments. -- Abstract: TRPML3 is a Ca{sup 2+} permeable cation channel expressed in multiple intracellular compartments. Although TRPML3 is implicated in autophagy, how TRPML3 can regulate autophagy is not understood. To search interacting proteins with TRPML3 in autophagy, we performed split-ubiquitin membrane yeast two-hybrid (MY2H) screening with TRPML3-loop as a bait and identified GATE16, a mammalian ATG8 homologue. GST pull-down assay revealed that TRPML3 and TRPML3-loop specifically bind to GATE16, not to LC3B. Co-immunoprecipitation (co-IP) experiments showed that TRPML3 and TRPML3-loop pull down only the lipidated form of GATE16, indicating that the interaction occurs exclusively at the organellar membrane. The interaction of TRPML3 with GATE16 and GATE16-positive vesicle formation were increased in starvation induced autophagy, suggesting that the interaction facilitates the function of GATE16 in autophagosome formation. However, GATE16 was not required for TRPML3 trafficking to autophagosomes. Experiments using dominant-negative (DN) TRPML3(D458K) showed that GATE16 is localized not only in autophagosomes but also in extra-autophagosomal compartments, by contrast with LC3B. Since GATE16 acts at a later stage of the autophagosome biogenesis, our results suggest that TRPML3 plays a role in autophagosome maturation through the interaction with GATE16, by providing Ca{sup 2+} in the fusion process.

  5. Regulation of body mass and adiposity in the field vole, Microtus agrestis: a model of leptin resistance.

    Science.gov (United States)

    Król, Elzbieta; Speakman, John R

    2007-02-01

    Adult mammals are typically highly resistant to perturbations in their energy balance. In obese humans, however, this control appears to be lost. Apart from a few exceptional cases, this loss of control occurs despite appropriate levels of circulating leptin -- suggesting that elevated adiposity may be a consequence of failure to respond to the leptin signal: leptin resistance. When cold-acclimated male field voles (Microtus agrestis) are transferred from short (SD, 8 h light) to long (LD, 16 h light) photoperiods, they increase dramatically in body mass and fatness for about 4 weeks. After this period, their mass stabilizes at a new plateau about 25% higher than animals maintained in SD. The increase in adiposity is not caused by significant increases in food intake, but reflects an increase in digestive efficiency. Measures of circulating leptin reveal that the increased adiposity is matched by increased circulating leptin. By infusing voles with exogenous leptin, we have demonstrated that SD voles are leptin sensitive (reducing both body mass and food intake), whereas LD animals are leptin resistant. Voles may therefore be a useful model for understanding the process of leptin resistance. The change in leptin sensitivity in voles was not associated with changes in the levels of gene expression of the orexogenic or anorexogenic neuropeptides, such as neuropeptide Y, agouti-related peptide, POMC and cocaine- and amphetamine-regulated transcript, measured in the hypothalamic arcuate nucleus (ARC). During the phase that body mass was increasing, however, there was a transient increase in the ARC expression of suppressor of cytokine signalling-3 (SOCS3). These data suggest that the changes in the expression of SOCS3 in the ARC may be involved in leptin resistance. However, the mechanism by which these changes may be linked to alterations in digestive efficiency that underpin the changes in adiposity, or how the differences are signalled by changes in photoperiod

  6. Fibrates inhibit the apoptosis of Batten disease lymphoblast cells via autophagy recovery and regulation of mitochondrial membrane potential.

    Science.gov (United States)

    Hong, Minho; Song, Ki Duk; Lee, Hak-Kyo; Yi, SunShin; Lee, Yong Seok; Heo, Tae-Hwe; Jun, Hyun Sik; Kim, Sung-Jo

    2016-03-01

    Batten disease (BD; also known as juvenile neuronal ceroid lipofuscinosis) is a genetic disorder inherited as an autosomal recessive trait and is characterized by blindness, seizures, cognitive decline, and early death resulting from the inherited mutation of the CLN3 gene. Mitochondrial oxidative stress, endoplasmic reticulum (ER) stress, disrupted autophagy, and enhanced apoptosis have been suggested to play a role in BD pathogenesis. Fibrates, a class of lipid-lowering drugs that induce peroxisome proliferator-activated receptor-α (PPAR-α) activation, are the most commonly used PPAR agonists. Assuming that fibrates have a neuroprotective effect, we studied the effects of fibrates, fenofibrate, bezafibrate, and gemfibrozil on apoptosis, depolarization of mitochondrial membrane, and defective autophagy in BD lymphoblast cells. The viability of fibrate-treated BD lymphoblast cells increased to levels of normal lymphoblast cells. In addition, treatment with fibrates inhibited depolarization of mitochondrial membrane potential in BD lymphoblast cells. Defective autophagy in BD lymphoblast cells was normalized when treated with fibrates as indicated by increased acridine orange staining. The recovery of autophagy in BD lymphoblast cells is most likely attributed to the upregulation of autophagy proteins, lysosomal-associated membrane protein 1 (LAMP1), and LC3 I/II, after treatment with fibrates. This study therefore suggests that fibrates may have a therapeutic potential against BD. PMID:26659390

  7. Autophagy regulation revealed by SapM-induced block of autophagosome-lysosome fusion via binding RAB7

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Dong, E-mail: austhudong@126.com [Institute of Infection and Immunology, Department of Medical Immunology, Medical School, Anhui University of Science and Technology, Huainan (China); Wu, Jing, E-mail: wujing8008@126.com [Institute of Infection and Immunology, Department of Medical Immunology, Medical School, Anhui University of Science and Technology, Huainan (China); Wang, Wan; Mu, Min; Zhao, Runpeng; Xu, Xuewei; Chen, Zhaoquan [Institute of Infection and Immunology, Department of Medical Immunology, Medical School, Anhui University of Science and Technology, Huainan (China); Xiao, Jian [School of Pharmacy, Wenzhou Medical College, Wenzhou (China); Hu, Fengyu; Yang, Yabo [Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou (China); Zhang, Rongbo, E-mail: lory456@126.com [Institute of Infection and Immunology, Department of Medical Immunology, Medical School, Anhui University of Science and Technology, Huainan (China)

    2015-05-29

    The mechanism underlying autophagy alteration by mycobacterium tuberculosis remains unclear. Our previous study shows LpqH, a lipoprotein of mycobacterium tuberculosis, can cause autophagosomes accumulation in murine macrophages. It is well known that SapM, another virulence factor, plays an important role in blocking phagosome-endosome fusion. However, the mechanism that SapM interferes with autophagy remains poorly defined. In this study, we report that SapM suppresses the autophagy flux by blocking autophagosome fusion with lysosome. Exposure to SapM results in accumulations of autophagosomes and decreased co-localization of autophagosome with lysosome. Molecularly, Rab7, a small GTPase, is blocked by SapM through its CT domain and is prevented from involvement of autophagosome-lysosome fusion. In conclusion, our study reveals that SapM takes Rab7 as a previously unknown target to govern a distinct molecular mechanism underlying autophagosome-lysosome fusion, which may bring light to a new thought about developing potential drugs or vaccines against tuberculosis. - Highlights: • A mechanism for disrupting autophagosome-lysosome fusion induced by SapM. • Rab7 is involved in SapM-inhibited autophagy. • SapM interacts with Rab7 by CT-domain. • CT-domain is indispensable to SapM-inhibited autophagy.

  8. Autophagy regulation revealed by SapM-induced block of autophagosome-lysosome fusion via binding RAB7

    International Nuclear Information System (INIS)

    The mechanism underlying autophagy alteration by mycobacterium tuberculosis remains unclear. Our previous study shows LpqH, a lipoprotein of mycobacterium tuberculosis, can cause autophagosomes accumulation in murine macrophages. It is well known that SapM, another virulence factor, plays an important role in blocking phagosome-endosome fusion. However, the mechanism that SapM interferes with autophagy remains poorly defined. In this study, we report that SapM suppresses the autophagy flux by blocking autophagosome fusion with lysosome. Exposure to SapM results in accumulations of autophagosomes and decreased co-localization of autophagosome with lysosome. Molecularly, Rab7, a small GTPase, is blocked by SapM through its CT domain and is prevented from involvement of autophagosome-lysosome fusion. In conclusion, our study reveals that SapM takes Rab7 as a previously unknown target to govern a distinct molecular mechanism underlying autophagosome-lysosome fusion, which may bring light to a new thought about developing potential drugs or vaccines against tuberculosis. - Highlights: • A mechanism for disrupting autophagosome-lysosome fusion induced by SapM. • Rab7 is involved in SapM-inhibited autophagy. • SapM interacts with Rab7 by CT-domain. • CT-domain is indispensable to SapM-inhibited autophagy

  9. Transcriptome profiling of brown adipose tissue during cold exposure reveals extensive regulation of glucose metabolism

    DEFF Research Database (Denmark)

    Hao, Qin; Yadav, Rachita; Basse, Astrid L.;

    2015-01-01

    We applied digital gene expression profiling to determine the transcriptome of brown and white adipose tissues (BAT and WAT, respectively) during cold exposure. Male C57BL/6J mice were exposed to cold for 2 or 4 days. A notable induction of genes related to glucose uptake, glycolysis, glycogen...

  10. G0/G1 switch gene-2 regulates human adipocyte lipolysis by affecting activity and localization of adipose triglyceride lipase

    OpenAIRE

    Schweiger, Martina; Paar, Margret; Eder, Christina; Brandis, Janina; Moser, Elena; Gorkiewicz, Gregor; Grond, Susanne; Radner, Franz P. W.; Cerk, Ines; Cornaciu, Irina; Oberer, Monika; Kersten, Sander; Zechner, Rudolf; Zimmermann, Robert; Lass, Achim

    2012-01-01

    The hydrolysis of triglycerides in adipocytes, termed lipolysis, provides free fatty acids as energy fuel. Murine lipolysis largely depends on the activity of adipose triglyceride lipase (ATGL), which is regulated by two proteins annotated as comparative gene identification-58 (CGI-58) and G0/G1 switch gene-2 (G0S2). CGI-58 activates and G0S2 inhibits ATGL activity. In contrast to mice, the functional role of G0S2 in human adipocyte lipolysis is poorly characterized. Here we show that overexp...

  11. Dietary soy isoflavones differentially regulate expression of the lipid-metabolic genes in different white adipose tissues of the female Bama mini-pigs.

    Science.gov (United States)

    Jiang, Guoli; Li, Lili; Fan, Juexin; Zhang, Bin; Oso, A O; Xiao, Chaowu; Yin, Yulong

    2015-05-22

    Soy isoflavones have been shown to affect lipid metabolism, however the underlying molecular mechanism(s) have not yet been fully understood. The present study, using female Bama mini-pig as a model, examined the effects of soy isoflavones on lipid metabolism and involved gene expression in different white adipose tissues. Female Bama Xiang mini-pigs of 35 days old were fed a basal diet (control, Con), or basal diet supplemented with increasing amounts of soy isoflavones (250, 500, or 1250 mg/kg diet) for 120 days. The results showed that soy isoflavones did not affect the body weight, but decreased the dorsal subcutaneous adipose tissue (DSA) mass and increased the mass of abdominal subcutaneous adipose tissue (ASA) and perirenal adipose tissue (PRA). Besides, soy isoflavones decreased the expression of lipogenic genes and increased the expression of lipolytic genes in DSA, while the opposite effects were observed in ASA and PRA. In addition, the expression of lipoprotein lipase was down regulated in DSA while up regulated in ASA and PRA by soy isoflavones. Moreover, the expression of estrogen receptors (ERs) was up regulated in DSA, and down regulated in ASA and PRA by soy isoflavones. Our results suggest that soy isoflavones affected the lipid metabolism in white adipose tissues of Bama mini-pigs in a site-specific manner, which might be mediated through PPARs and ERs regulated gene expression.

  12. Ordered bulk degradation via autophagy

    DEFF Research Database (Denmark)

    Dengjel, Jörn; Kristensen, Anders Riis; Andersen, Jens S

    2008-01-01

    During amino acid starvation, cells undergo macroautophagy which is regarded as an unspecific bulk degradation process. Lately, more and more organelle-specific autophagy subtypes such as reticulophagy, mitophagy and ribophagy have been described and it could be shown, depending on the experimental...... setup, that autophagy specifically can remove certain subcellular components. We used an unbiased quantitative proteomics approach relying on stable isotope labeling by amino acids in cell culture (SILAC) to study global protein dynamics during amino acid starvation-induced autophagy. Looking...... at proteasomal and lysosomal degradation ample cross-talk between the two degradation pathways became evident. Degradation via autophagy appeared to be ordered and regulated at the protein complex/organelle level. This raises several important questions such as: can macroautophagy itself be specific and what...

  13. Autophagy in DNA Damage Response

    Directory of Open Access Journals (Sweden)

    Piotr Czarny

    2015-01-01

    Full Text Available DNA damage response (DDR involves DNA repair, cell cycle regulation and apoptosis, but autophagy is also suggested to play a role in DDR. Autophagy can be activated in response to DNA-damaging agents, but the exact mechanism underlying this activation is not fully understood, although it is suggested that it involves the inhibition of mammalian target of rapamycin complex 1 (mTORC1. mTORC1 represses autophagy via phosphorylation of the ULK1/2–Atg13–FIP200 complex thus preventing maturation of pre-autophagosomal structures. When DNA damage occurs, it is recognized by some proteins or their complexes, such as poly(ADPribose polymerase 1 (PARP-1, Mre11–Rad50–Nbs1 (MRN complex or FOXO3, which activate repressors of mTORC1. SQSTM1/p62 is one of the proteins whose levels are regulated via autophagic degradation. Inhibition of autophagy by knockout of FIP200 results in upregulation of SQSTM1/p62, enhanced DNA damage and less efficient damage repair. Mitophagy, one form of autophagy involved in the selective degradation of mitochondria, may also play role in DDR. It degrades abnormal mitochondria and can either repress or activate apoptosis, but the exact mechanism remains unknown. There is a need to clarify the role of autophagy in DDR, as this process may possess several important biomedical applications, involving also cancer therapy.

  14. Ursolic acid attenuates diabetic mesangial cell injury through the up-regulation of autophagy via miRNA-21/PTEN/Akt/mTOR suppression.

    Directory of Open Access Journals (Sweden)

    Xinxing Lu

    Full Text Available To investigate the effect of ursolic acid on autophagy mediated through the miRNA-21-targeted phosphoinositide 3 kinase (PI3K/protein kinase B (Akt/mammalian target of rapamycin (mTOR pathway in rat mesangial cells cultured under high glucose (HG conditions.Rat glomerular mesangial cells were cultured under normal glucose, HG, HG with the PI3K inhibitor LY294002 or HG with ursolic acid conditions. Cell proliferation and hypertrophy were assayed using an MTT assay and the ratio of total protein to cell number, respectively. The miRNA-21 expression was detected using RT-qPCR. The expression of phosphatase and tensin homolog (PTEN/AKT/mTOR signaling signatures, autophagy-associated protein and collagen I was detected by western blotting and RT-qPCR. Autophagosomes were observed using electron microscopy.Compared with mesangial cells cultured under normal glucose conditions, the cells exposed to HG showed up-regulated miRNA-21 expression, down-regulated PTEN protein and mRNA expression, up-regulated p85PI3K, pAkt, pmTOR, p62/SQSTMI, and collagen I expression and down-regulated LC3II expression. Ursolic acid and LY294002 inhibited HG-induced mesangial cell hypertrophy and proliferation, down-regulated p85PI3K, pAkt, pmTOR, p62/SQSTMI, and collagen I expression and up-regulated LC3II expression. However, LY294002 did not affect the expression of miRNA-21 and PTEN. Ursolic acid down-regulated miRNA-21 expression and up-regulated PTEN protein and mRNA expression.Ursolic acid inhibits the glucose-induced up-regulation of mesangial cell miRNA-21 expression, up-regulates PTEN expression, inhibits the activation of PI3K/Akt/mTOR signaling pathway, and enhances autophagy to reduce the accumulation of the extracellular matrix and ameliorate cell hypertrophy and proliferation.

  15. Autophagy and Retromer Components in Plant Innate Immunity

    DEFF Research Database (Denmark)

    Munch, David

    -hormone salicylic acid. Here, I present data that make it clear that NPR1 does not directly regulate autophagy, but instead control stress responses that indirectly activate autophagy. The observations presented will also clarify why autophagy has been described as being both a pro-death and pro-life pathway under...

  16. Autophagy and the nutritional signaling pathway

    Directory of Open Access Journals (Sweden)

    Long HE,Shabnam ESLAMFAM,Xi MA,Defa LI

    2016-09-01

    Full Text Available During their growth and development, animals adapt to tremendous changes in order to survive. These include responses to both environmental and physiological changes and autophagy is one of most important adaptive and regulatory mechanisms. Autophagy is defined as an autolytic process to clear damaged cellular organelles and recycle the nutrients via lysosomic degradation. The process of autophagy responds to special conditions such as nutrient withdrawal. Once autophagy is induced, phagophores form and then elongate and curve to form autophagosomes. Autophagosomes then engulf cargo, fuse with endosomes, and finally fuse with lysosomes for maturation. During the initiation process, the ATG1/ULK1 (unc-51-like kinase 1 and VPS34 (which encodes a class III phosphatidylinositol (PtdIns 3-kinase complexes are critical in recruitment and assembly of other complexes required for autophagy. The process of autophagy is regulated by autophagy related genes (ATGs. Amino acid and energy starvation mediate autophagy by activating mTORC1 (mammalian target of rapamycin and AMP-activated protein kinase (AMPK. AMPK is the energy status sensor, the core nutrient signaling component and the metabolic kinase of cells. This review mainly focuses on the mechanism of autophagy regulated by nutrient signaling especially for the two important complexes, ULK1 and VPS34.

  17. Regulation of autophagy via PERK-eIF2α effectively relieve the radiation myelitis induced by iodine-125.

    Directory of Open Access Journals (Sweden)

    Zuozhang Yang

    Full Text Available Radiation myelitis is the most serious complication in clinical radiotherapy for spinal metastases. We previously showed that (125I brachytherapy induced apoptosis of spinal cord neurons accompanied by autophagy. In this study, we further investigated the mechanism by which (125I radiation triggered autophagy in neural cells. We found that autophagy induced by (125I radiation was involved in endoplasmic reticulum (ER stress and mainly dependent on PERK-eIF2α pathway. The expressions of LC3II, ATG12 and PI3K were significantly suppressed in PERK knockout neural cells. Meanwhile, the expressions of phosphorylated-Akt s473 and caspase3/8 all significantly increased in neural cells transfected with a PERK siRNA and which enhanced apoptosis of neurons after (125I radiation. The results were consistent with that by MTT and Annexin-FITC/PT staining. In animal model of banna pigs with radiation myelitis caused by (125I brachytherapy, we have successfully decreased PERK expression by intrathecal administration of the lentivirus vector. The apoptosis rate was significantly higher than that in control group and which deteriorated radiation myelitis of banna pigs. Thus, autophagy caused by (125I radiation was mainly as an attempt of cell survival at an early stage, but it would be a self-destructive process and promoted the process of apoptosis and necrosis radiated by (125I for more than 72 hours. The study would be useful and helpful to maximize efficiency of radiation therapy in clinical therapy.

  18. Weight gain and inflammation regulate aromatase expression in male adipose tissue, as evidenced by reporter gene activity.

    Science.gov (United States)

    Polari, L; Yatkin, E; Martínez Chacón, M G; Ahotupa, M; Smeds, A; Strauss, L; Zhang, F; Poutanen, M; Saarinen, N; Mäkelä, S I

    2015-09-01

    Obesity and white adipose tissue (WAT) inflammation are associated with enhanced aromatization in women, but little is known about the regulation of aromatase (CYP19A1) gene expression in male WAT. We investigated the impact of weight gain and WAT inflammation on the regulation of CYP19A1 in males, by utilizing the hARO-Luc aromatase reporter mouse model containing a >100-kb 5'-region of the human CYP19A1 gene. We show that hARO-Luc reporter activity is enhanced in WAT of mice with increased adiposity and inflammation. Dexamethasone and TNFα, as well as forskolin and phorbol 12-myristate 13-acetate, upregulate hARO-Luc activity, suggesting the involvement of promoters I.4 and I.3/II. Furthermore, we show that diet enriched with antioxidative plant polyphenols attenuates WAT inflammation and hARO-Luc activity in obese males. In conclusion, our data suggest that obesity-associated WAT inflammation leads to increased peripheral CYP19A1 expression in males, and that polyphenol-enriched diet may have the potential to attenuate excessive aromatization in WAT of obese men. PMID:26054748

  19. Keeping autophagy in cheCK1

    Science.gov (United States)

    Cheong, Jit Kong; Virshup, David M.

    2016-01-01

    Abstract Mutant RAS-driven cancer cells cope with proliferative stress by increasing basal autophagy to maintain protein/organelle and energy homeostasis. We recently demonstrated that casein kinase 1 alpha (CK1α), a therapeutically tractable enzyme, is critical for fine-tuning the transcriptional regulation of mutant RAS-induced autophagy and the development of mutant RAS-driven cancers. PMID:27314070

  20. White Adipose Tissue Development in Zebrafish Is Regulated by Both Developmental Time and Fish Size

    OpenAIRE

    Imrie, Dru; Sadler, Kirsten C.

    2010-01-01

    Adipocytes are heterogeneous. Whether their differences are attributed to anatomical location or to different developmental origins is unknown. We investigated whether development of different white adipose tissue (WAT) depots in zebrafish occurs simultaneously or whether adipogenesis is influenced by the metabolic demands of growing fish. Like mammals, zebrafish adipocyte morphology is distinctive and adipocytes express cell-specific markers. All adults contain WAT in pancreatic, subcutaneou...

  1. Regulation of fructose 2,6-bisphosphate concentration in white adipose tissue.

    OpenAIRE

    Rider, Mark; Hue, Louis

    1985-01-01

    Injection of insulin to fed rats diminished the concentration of fructose 2,6-bisphosphate in white adipose tissue. Incubation of epididymal fat-pads or adipocytes with insulin stimulated lactate release and sugar detritiation and also decreased fructose 2,6-bisphosphate concentration. Such a decrease was, however, not observed in fat-pads from starved or alloxan-diabetic rats. Incubation of adipocytes from fed rats with various concentrations of glucose or fructose led to a dose-dependent ri...

  2. The metastasis suppressor, N-myc downstream-regulated gene 1 (NDRG1), inhibits stress-induced autophagy in cancer cells.

    Science.gov (United States)

    Sahni, Sumit; Bae, Dong-Hun; Lane, Darius J R; Kovacevic, Zaklina; Kalinowski, Danuta S; Jansson, Patric J; Richardson, Des R

    2014-04-01

    N-myc downstream regulated gene 1 (NDRG1) is a potent metastasis suppressor with an undefined role in the stress response. Autophagy is a pro-survival pathway and can be regulated via the protein kinase-like endoplasmic reticulum kinase (PERK)/eIF2α-mediated endoplasmic reticulum (ER) stress pathway. Hence, we investigated the role of NDRG1 in stress-induced autophagy as a mechanism of inhibiting metastasis via the induction of apoptosis. As thiosemicarbazone chelators induce stress and up-regulate NDRG1 to inhibit metastasis, we studied their effects on the ER stress response and autophagy. This was important to assess, as little is understood regarding the role of the stress induced by iron depletion and its role in autophagy. We observed that the chelator, di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), which forms redox-active iron and copper complexes, effectively induced ER stress as shown by activation of the PERK/eIF2α pathway. Dp44mT also increased the expression of the autophagic marker, LC3-II, and this was dependent on activation of the PERK/eIF2α axis, as silencing PERK prevented LC3-II accumulation. The effect of Dp44mT on LC3-II expression was at least partially due to iron-depletion, as this effect was also demonstrated with the classical iron chelator, desferrioxamine (DFO), and was not observed for the DFO-iron complex. NDRG1 overexpression also inhibited basal autophagic initiation and the ER stress-mediated autophagic pathway via suppression of the PERK/eIF2α axis. Moreover, NDRG1-mediated suppression of the pro-survival autophagic pathway probably plays a role in its anti-metastatic effects by inducing apoptosis. In fact, multiple pro-apoptotic markers were increased, whereas anti-apoptotic Bcl-2 was decreased upon NDRG1 overexpression. This study demonstrates the role of NDRG1 as an autophagic inhibitor that is important for understanding its mechanism of action. PMID:24532803

  3. Regulation of UCP1 in the Browning of Epididymal Adipose Tissue by β3-Adrenergic Agonist: A Role for MicroRNAs

    Directory of Open Access Journals (Sweden)

    Zongji Zheng

    2014-01-01

    Full Text Available Background. White adipose tissue browning may be a promising strategy to combat obesity. UCP1 is strongly induced in White adipose tissue with β3-adrenergic agonist treatment, but the causes of this increase have not been fully elucidated. This study aims to explore more miRNAs involved in the process of browning of visceral adipose tissue. Methods. Total of fourteen mice were randomly divided into control and study group. Study group mice were injected intraperitoneally with CL316243 once daily for seven days; meanwhile the control group were treated with 0.9% NaCl. After a 7-day period, the expression of genes involved in WAT browning and potential UCP1-targeting miRNAs in adipose tissues was analyzed by qPCR. Results. qPCR analysis revealed that UCP1, DIO2, CIDEA, and CPT1B in epididymal adipose tissue were overexpressed in CL316243 group. Furthermore, potential UCP1-targeting miR-9 and miR-338-3p in epididymal adipose tissue were significantly decreased in CL316243 group. Conclusion. This suggests that potential UCP1-targeting miR-9 and miR-338-3p may be involved in the browning of epididymal adipose tissue by regulating UCP1 gene expression. In this study, we demonstrated that this increase of UCP1 is due, at least in part, to the decreased expression of certain UCP1-targeting miRNAs in epididymal adipose tissue compared to control.

  4. Autophagy-associated immune responses and cancer immunotherapy

    Science.gov (United States)

    Xu, Yinghua; Han, Weidong; Lou, Fang; Fei, Weiqiang; Liu, Shuiping; Jing, Zhao; Sui, Xinbing

    2016-01-01

    Autophagy is an evolutionarily conserved catabolic process by which cellular components are sequestered into a double-membrane vesicle and delivered to the lysosome for terminal degradation and recycling. Accumulating evidence suggests that autophagy plays a critical role in cell survival, senescence and homeostasis, and its dysregulation is associated with a variety of diseases including cancer, cardiovascular disease, neurodegeneration. Recent studies show that autophagy is also an important regulator of cell immune response. However, the mechanism by which autophagy regulates tumor immune responses remains elusive. In this review, we will describe the role of autophagy in immune regulation and summarize the possible molecular mechanisms that are currently well documented in the ability of autophagy to control cell immune response. In addition, the scientific and clinical hurdles regarding the potential role of autophagy in cancer immunotherapy will be discussed. PMID:26788909

  5. Autophagy-associated immune responses and cancer immunotherapy.

    Science.gov (United States)

    Pan, Hongming; Chen, Liuxi; Xu, Yinghua; Han, Weidong; Lou, Fang; Fei, Weiqiang; Liu, Shuiping; Jing, Zhao; Sui, Xinbing

    2016-04-19

    Autophagy is an evolutionarily conserved catabolic process by which cellular components are sequestered into a double-membrane vesicle and delivered to the lysosome for terminal degradation and recycling. Accumulating evidence suggests that autophagy plays a critical role in cell survival, senescence and homeostasis, and its dysregulation is associated with a variety of diseases including cancer, cardiovascular disease, neurodegeneration. Recent studies show that autophagy is also an important regulator of cell immune response. However, the mechanism by which autophagy regulates tumor immune responses remains elusive. In this review, we will describe the role of autophagy in immune regulation and summarize the possible molecular mechanisms that are currently well documented in the ability of autophagy to control cell immune response. In addition, the scientific and clinical hurdles regarding the potential role of autophagy in cancer immunotherapy will be discussed.

  6. Tumor Suppression and Promotion by Autophagy

    Directory of Open Access Journals (Sweden)

    Yenniffer Ávalos

    2014-01-01

    Full Text Available Autophagy is a highly regulated catabolic process that involves lysosomal degradation of proteins and organelles, mostly mitochondria, for the maintenance of cellular homeostasis and reduction of metabolic stress. Problems in the execution of this process are linked to different pathological conditions, such as neurodegeneration, aging, and cancer. Many of the proteins that regulate autophagy are either oncogenes or tumor suppressor proteins. Specifically, tumor suppressor genes that negatively regulate mTOR, such as PTEN, AMPK, LKB1, and TSC1/2 stimulate autophagy while, conversely, oncogenes that activate mTOR, such as class I PI3K, Ras, Rheb, and AKT, inhibit autophagy, suggesting that autophagy is a tumor suppressor mechanism. Consistent with this hypothesis, the inhibition of autophagy promotes oxidative stress, genomic instability, and tumorigenesis. Nevertheless, autophagy also functions as a cytoprotective mechanism under stress conditions, including hypoxia and nutrient starvation, that promotes tumor growth and resistance to chemotherapy in established tumors. Here, in this brief review, we will focus the discussion on this ambiguous role of autophagy in the development and progression of cancer.

  7. Modulating autophagy: a strategy for cancer therapy

    Institute of Scientific and Technical Information of China (English)

    Jun-Lin Li; Shao-Liang Han; Xia Fan

    2011-01-01

    Autophagy is a process in which long-lived proteins,damaged cell organelles,and other cellular particles are sequestered and degraded.This process is important for maintaining the cellular microenvironment when the cell is under stress.Many studies have shown that autophagy plays a complex role in human diseases,especially in cancer,where it is known to have paradoxical effects.Namely,autophagy provides the energy for metabolism and tumor growth and leads to cell death that promotes tumor suppression.The link between autophagy and cancer is also evident in that some of the genes that regulate carcinogenesis,oncogenes and tumor suppressor genes,participate in or impact the autophagy process.Therefore,modulating autophagy will be a valuable topic for cancer therapy.Many studies have shown that autophagy can inhibit the tumor growth when autophagy modulators are combined with radiotherapy and/or chemotherapy.These findings suggest that autophagy may be a potent target for cancer therapy.

  8. Oridonin Up-regulates Expression of P21 and Induces Autophagy and Apoptosis in Human Prostate Cancer Cells

    Directory of Open Access Journals (Sweden)

    Xiang Li, Xiang Li, Jiaxiong Wang, Zaiyuan Ye, Ji-Cheng Li

    2012-01-01

    Full Text Available Background: Oridonin (ORI could inhibit the proliferation and induce apoptosis in various cancer cell lines. However, the mechanism is not fully understood.Methods: Human prostate cancer (HPC cells were cultured in vitro and cell viability was detected by the CCK-8 assay. The ultrastructure changes were observed under transmission electron microscope (TEM. Chemical staining with acridine orange (AO, MDC or DAPI was used to detect acidic vesicular organelles (AVOs and alternation of DNA. Expression of LC3 and P21 was detected by Western Blot. Apoptotic rates and cell cycle arrest were detected by FACS.Results: Our study demonstrated that after ORI treatment, the proliferations of human prostate cancer (HPC cell lines PC-3 and LNCaP were inhibited in a concentration and time-dependent manner. ORI induced cell cycle arrest at the G2/M phase. A large number of autophagosomes with double-membrane structure and acidic vesicular organelles (AVOs were detected in the cytoplasm of HPC cells treated with ORI for 24 hours. ORI resulted in the conversion of LC3-I to LC3-II and recruitment of LC3-II to the autophagosomal membranes. Autophagy inhibitor 3-methyladenine (3-MA reduced AVOs formation and inhibited LC3-I to LC3-II conversion. At 48 h, DNA fragmentation, chromatin condensation and disappearance of surface microvilli were detected in ORI-treated cells. ORI induced a significant increase in the number of apoptotic cells (PC-3: 5.4% to 27.0%, LNCaP: 5.3% to 31.0%. Promoting autophagy by nutrient starvation increased cell viability, while inhibition of autophagy by 3-MA promoted cell death. The expression of P21 was increased by ORI, which could be completely reversed by the inhibition of autophagy.Conclusions: Our findings indicated that autophagy occurred before the onset of apoptosis and protected cancer cells in ORI-treated HPC cells. P21 was involved in ORI-induced autophagy and apoptosis. Our results provide an experimental basis for understand

  9. Autophagy to Survive

    Directory of Open Access Journals (Sweden)

    Muzeyyen Izmirli

    2014-06-01

    Full Text Available Autophagy is the catabolic mechanism that involves cell degradation of unnecessary or dysfunctional cellular components through the actions of lysosomes. It helps to keep the cells alive in such cases like oxidative stress, lack of nutrients and growth factors providing recycling of intracellular molecules. However, it works as a part of metabolism regulation, morphogenesis, cell differentiation, senescence, cell death and immune system. As a result of impairment of this mechanism, pathological situations arise including cancer, neurodegenerative and infectious diseases. Consequently, researches about autophagy mechanism are important for the development of novel diagnosis, follow-up and treatment modalities in health problems. [Archives Medical Review Journal 2014; 23(3.000: 411-419

  10. Autophagy in the control of food intake.

    Science.gov (United States)

    Singh, Rajat

    2012-04-01

    The cellular nutrient sensing apparatus detects nutritional depletion and transmits this information to downstream effectors that generate energy from alternate sources. Autophagy is a crucial catabolic pathway that turns over redundant cytoplasmic components in lysosomes to provide energy to the starved cell. Recent studies have described a role for hypothalamic autophagy in the control of food intake and energy balance. Activated autophagy in hypothalamic neurons during starvation mobilized neuron-intrinsic lipids to generate free fatty acids that increased AgRP levels. AgRP neuron-specific inhibition of autophagy decreased fasting-induced increases in AgRP levels and food intake. Deletion of autophagy in AgRP neurons led to constitutive increases in levels of proopiomelanocortin and its active processed product, α-melanocyte stimulating hormone that contributed to reduced adiposity in these rodents. The current manuscript discusses these new findings and raises additional questions that may help understand how hypothalamic autophagy controls food intake and energy balance. These studies may have implications for designing new therapies against obesity and insulin resistance. PMID:23700515

  11. Emerging connections between RNA and autophagy

    DEFF Research Database (Denmark)

    Frankel, Lisa B; Lubas, Michal; Lund, Anders H

    2016-01-01

    Macroautophagy/autophagy is a key catabolic process, essential for maintaining cellular homeostasis and survival through the removal and recycling of unwanted cellular material. Emerging evidence has revealed intricate connections between the RNA and autophagy research fields. While a majority...... of studies have focused on protein, lipid and carbohydrate catabolism via autophagy, accumulating data supports the view that several types of RNA and associated ribonucleoprotein complexes are specifically recruited to phagophores (precursors to autophagosomes) and subsequently degraded in the lysosome....../vacuole. Moreover, recent studies have revealed a substantial number of novel autophagy regulators with RNA-related functions, indicating roles for RNA and associated proteins not only as cargo, but also as regulators of this process. In this review, we discuss widespread evidence of RNA catabolism via autophagy...

  12. Beta(3)-adrenergic signaling acutely down regulates adipose triglyceride lipase in brown adipocytes.

    Science.gov (United States)

    Deiuliis, Jeffrey A; Liu, Li-Fen; Belury, Martha A; Rim, Jong S; Shin, Sangsu; Lee, Kichoon

    2010-06-01

    Mice exposed to cold rely upon brown adipose tissue (BAT)-mediated nonshivering thermogenesis to generate body heat using dietary glucose and lipids from the liver and white adipose tissue. In this report, we investigate how cold exposure affects the PI3 K/Akt signaling cascade and the expression of genes involved in lipid metabolism and trafficking in BAT. Cold exposure at an early time point led to the activation of the PI3 K/Akt, insulin-like signaling cascade followed by a transient decrease in adipose triglyceride lipase (ATGL) gene and protein expression in BAT. To further investigate how cold exposure-induced signaling altered ATGL expression, cultured primary brown adipocytes were treated with the beta(3)-adrenergic receptor (beta(3)AR) agonist CL 316,243 (CL) resulting in activation of PI3 K/Akt, ERK 1/2, and p38 signaling pathways and significantly decreased ATGL protein levels. ATGL protein levels decreased significantly 30 min post CL treatment suggesting protein degradation. Inhibition of PKA signaling by H89 rescued ATGL levels. The effects of PKA signaling on ATGL were shown to be independent of relevant pathways downstream of PKA such as PI3 K/Akt, ERK 1/2, and p38. However, CL treatment in 3T3-L1 adipocytes did not decrease ATGL protein and mRNA expression, suggesting a distinct response in WAT to beta3-adrenergic agonism. Transitory effects, possibly attributed to acute Akt activation during the early recruitment phase, were noted as well as stable changes in gene expression which may be attributed to beta3-adrenergic signaling in BAT.

  13. SPBP is a sulforaphane induced transcriptional coactivator of NRF2 regulating expression of the autophagy receptor p62/SQSTM1.

    Science.gov (United States)

    Darvekar, Sagar Ramesh; Elvenes, Julianne; Brenne, Hanne Britt; Johansen, Terje; Sjøttem, Eva

    2014-01-01

    Organisms exposed to oxidative stress respond by orchestrating a stress response to prevent further damage. Intracellular levels of antioxidant agents increase, and damaged components are removed by autophagy induction. The KEAP1-NRF2 signaling pathway is the main pathway responsible for cell defense against oxidative stress and for maintaining the cellular redox balance at physiological levels. Sulforaphane, an isothiocyanate derived from cruciferous vegetables, is a potent inducer of KEAP1-NRF2 signaling and antioxidant response element driven gene expression. In this study, we show that sulforaphane enhances the expression of the transcriptional coregulator SPBP. The expression curve peaks 6-8 hours post stimulation, and parallels the sulforaphane-induced expression of NRF2 and the autophagy receptor protein p62/SQSTM1. Reporter gene assays show that SPBP stimulates the expression of p62/SQSTM1 via ARE elements in the promoter region, and siRNA mediated knock down of SPBP significantly decreases the expression of p62/SQSTM1 and the formation of p62/SQSTM1 bodies in HeLa cells. Furthermore, SPBP siRNA reduces the sulforaphane induced expression of NRF2, and the expression of the autophagy marker protein LC3B. Both these proteins contain ARE-like elements in their promoter regions. Over-expressed SPBP and NRF2 acts synergistically on the p62/SQSTM1 promoter and colocalize in nuclear speckles in HeLa cells. Collectively, these results suggest that SPBP is a coactivator of NRF2, and hence may be important for securing enhanced and sustained expression of NRF2 induced genes such as proteins involved in selective autophagy.

  14. SPBP is a sulforaphane induced transcriptional coactivator of NRF2 regulating expression of the autophagy receptor p62/SQSTM1.

    Directory of Open Access Journals (Sweden)

    Sagar Ramesh Darvekar

    Full Text Available Organisms exposed to oxidative stress respond by orchestrating a stress response to prevent further damage. Intracellular levels of antioxidant agents increase, and damaged components are removed by autophagy induction. The KEAP1-NRF2 signaling pathway is the main pathway responsible for cell defense against oxidative stress and for maintaining the cellular redox balance at physiological levels. Sulforaphane, an isothiocyanate derived from cruciferous vegetables, is a potent inducer of KEAP1-NRF2 signaling and antioxidant response element driven gene expression. In this study, we show that sulforaphane enhances the expression of the transcriptional coregulator SPBP. The expression curve peaks 6-8 hours post stimulation, and parallels the sulforaphane-induced expression of NRF2 and the autophagy receptor protein p62/SQSTM1. Reporter gene assays show that SPBP stimulates the expression of p62/SQSTM1 via ARE elements in the promoter region, and siRNA mediated knock down of SPBP significantly decreases the expression of p62/SQSTM1 and the formation of p62/SQSTM1 bodies in HeLa cells. Furthermore, SPBP siRNA reduces the sulforaphane induced expression of NRF2, and the expression of the autophagy marker protein LC3B. Both these proteins contain ARE-like elements in their promoter regions. Over-expressed SPBP and NRF2 acts synergistically on the p62/SQSTM1 promoter and colocalize in nuclear speckles in HeLa cells. Collectively, these results suggest that SPBP is a coactivator of NRF2, and hence may be important for securing enhanced and sustained expression of NRF2 induced genes such as proteins involved in selective autophagy.

  15. Altered gut microbiota and endocannabinoid system tone in obese and diabetic leptin-resistant mice: impact on apelin regulation in adipose tissue

    NARCIS (Netherlands)

    Geurts, L.; Vos, de W.M.

    2011-01-01

    Growing evidence supports the role of gut microbiota in the development of obesity, type 2 diabetes, and low-grade inflammation. The endocrine activity of adipose tissue has been found to contribute to the regulation of glucose homeostasis and low-grade inflammation. Among the key hormones produced

  16. Dioscin strengthens the efficiency of adriamycin in MCF-7 and MCF-7/ADR cells through autophagy induction: More than just down-regulation of MDR1.

    Science.gov (United States)

    Wang, Changyuan; Huo, Xiaokui; Wang, Lijuan; Meng, Qiang; Liu, Zhihao; Liu, Qi; Sun, Huijun; Sun, Pengyuan; Peng, Jinyong; Liu, Kexin

    2016-01-01

    The purpose of present study was to investigate the effect of dioscin on activity of adriamycin (ADR) in ADR-sensitive (MCF-7) and ADR-resistant (MCF-7/ADR) human breast cancer cells and to clarify the molecular mechanisms involved. Antiproliferation effect of ADR was enhanced by dioscin in MCF-7 and MCF-7/ADR cells. Dioscin significantly inhibited MDR1 mRNA and protein expression and MDR1 promoter and nuclear factor κ-B (NF-κB) activity in MCF-7/ADR cells. Additionally, inhibitor κB-α (IκB-α) degradation was inhibited by dioscin. Moreover, dioscin induced the formation of vacuoles in the cytoplasm and protein level of LC3-II in MCF-7 and MCF-7/ADR cells. Autophagy inhibitor 3-MA abolished the effect of dioscin on ADR cytotoxicity. Dioscin inhibited phosphorylation of PI3K and Akt, resulting in upregulation of LC3-II expression. In conclusion, dioscin increased ADR chemosensitivity by down-regulating MDR1 expression through NF-κB signaling inhibition in MCF-7/ADR cells. Autophagy was induced by dioscin to ameliorate the cytotoxicity of ADR via inhibition of the PI3K/AKT pathways in MCF-7 and MCF-7/ADR cells. These findings provide evidence in support of further investigation into the clinical application of dioscin as a chemotherapy adjuvant. PMID:27329817

  17. Exercise reduces adipose tissue via cannabinoid receptor type 1 which is regulated by peroxisome proliferator-activated receptor-δ

    International Nuclear Information System (INIS)

    Obesity is one major cardiovascular risk factor. We tested effects of endurance exercise on cannabinoid receptor type 1 (CB1) and peroxisome proliferator-activated receptor-δ (PPAR-δ)-dependent pathways in adipose tissue. Male Wistar rats were randomly assigned to standard laboratory chow or a high-fat diet without and with regular endurance exercise. Exercise in rats on high-fat diet significantly reduced visceral fat mass, blood pressure, and adipocyte size (each p < 0.05). Adipocyte hypertrophy induced by high-fat diet was accompanied by increased CB1 expression in adipose tissue, whereas exercise significantly reduced CB1 expression (each p < 0.05). CB1 receptor expression and adipocyte differentiation were directly regulated by PPAR-δ. Adipocyte hypertrophy induced by high-fat diet was accompanied by reduced PPAR-δ. Furthermore, selective silencing of PPAR-δ by RNA interference in 3T3-L1-preadipocyte cells significantly increased CB1 expression from 1.00 ± 0.06 (n = 3) to 1.91 ± 0.06 (n = 3; p < 0.01) and increased adipocyte differentiation, whereas adenovirus-mediated overexpression of PPAR-δ significantly reduced CB1 expression to 0.39 ± 0.03 (n = 3; p < 0.01) and reduced adipocyte differentiation. In the presence of the CB1 antagonist rimonabant adipocyte differentiation in stimulated 3T3 L1 preadipocyte cells was significantly reduced. The study indicates that high-fat diet-induced hypertrophy of adipocytes is associated with increased CB1 receptor expression which is directly regulated by PPAR-δ. Both CB1 and PPAR-δ are intimately involved in therapeutic interventions against a most important cardiovascular risk factor

  18. Exercise reduces adipose tissue via cannabinoid receptor type 1 which is regulated by peroxisome proliferator-activated receptor-delta.

    Science.gov (United States)

    Yan, Zhen Cheng; Liu, Dao Yan; Zhang, Li Li; Shen, Chen Yi; Ma, Qun Li; Cao, Ting Bing; Wang, Li Juan; Nie, Hai; Zidek, Walter; Tepel, Martin; Zhu, Zhi Ming

    2007-03-01

    Obesity is one major cardiovascular risk factor. We tested effects of endurance exercise on cannabinoid receptor type 1 (CB1) and peroxisome proliferator-activated receptor-delta (PPAR-delta)-dependent pathways in adipose tissue. Male Wistar rats were randomly assigned to standard laboratory chow or a high-fat diet without and with regular endurance exercise. Exercise in rats on high-fat diet significantly reduced visceral fat mass, blood pressure, and adipocyte size (each pAdipocyte hypertrophy induced by high-fat diet was accompanied by increased CB1 expression in adipose tissue, whereas exercise significantly reduced CB1 expression (each padipocyte differentiation were directly regulated by PPAR-delta. Adipocyte hypertrophy induced by high-fat diet was accompanied by reduced PPAR-delta. Furthermore, selective silencing of PPAR-delta by RNA interference in 3T3-L1-preadipocyte cells significantly increased CB1 expression from 1.00+/-0.06 (n=3) to 1.91+/-0.06 (n=3; padipocyte differentiation, whereas adenovirus-mediated overexpression of PPAR-delta significantly reduced CB1 expression to 0.39+/-0.03 (n=3; padipocyte differentiation. In the presence of the CB1 antagonist rimonabant adipocyte differentiation in stimulated 3T3 L1 preadipocyte cells was significantly reduced. The study indicates that high-fat diet-induced hypertrophy of adipocytes is associated with increased CB1 receptor expression which is directly regulated by PPAR-delta. Both CB1 and PPAR-delta are intimately involved in therapeutic interventions against a most important cardiovascular risk factor. PMID:17223076

  19. Increased mitochondrial fission promotes autophagy and hepatocellular carcinoma cell survival through the ROS-modulated coordinated regulation of the NFKB and TP53 pathways.

    Science.gov (United States)

    Huang, Qichao; Zhan, Lei; Cao, Haiyan; Li, Jibin; Lyu, Yinghua; Guo, Xu; Zhang, Jing; Ji, Lele; Ren, Tingting; An, Jiaze; Liu, Bingrong; Nie, Yongzhan; Xing, Jinliang

    2016-06-01

    Mitochondrial morphology is dynamically remodeled by fusion and fission in cells, and dysregulation of this process is closely implicated in tumorigenesis. However, the mechanism by which mitochondrial dynamics influence cancer cell survival is considerably less clear, especially in hepatocellular carcinoma (HCC). In this study, we systematically investigated the alteration of mitochondrial dynamics and its functional role in the regulation of autophagy and HCC cell survival. Furthermore, the underlying molecular mechanisms and therapeutic application were explored in depth. Mitochondrial fission was frequently upregulated in HCC tissues mainly due to an elevated expression ratio of DNM1L to MFN1, which significantly contributed to poor prognosis of HCC patients. Increased mitochondrial fission by forced expression of DNM1L or knockdown of MFN1 promoted the survival of HCC cells both in vitro and in vivo mainly by facilitating autophagy and inhibiting mitochondria-dependent apoptosis. We further demonstrated that the survival-promoting role of increased mitochondrial fission was mediated via elevated ROS production and subsequent activation of AKT, which facilitated MDM2-mediated TP53 degradation, and NFKBIA- and IKK-mediated transcriptional activity of NFKB in HCC cells. Also, a crosstalk between TP53 and NFKB pathways was involved in the regulation of mitochondrial fission-mediated cell survival. Moreover, treatment with mitochondrial division inhibitor-1 significantly suppressed tumor growth in an in vivo xenograft nude mice model. Our findings demonstrate that increased mitochondrial fission plays a critical role in regulation of HCC cell survival, which provides a strong evidence for this process as drug target in HCC treatment. PMID:27124102

  20. Autophagy is an inflammation-related defensive mechanism against disease.

    Science.gov (United States)

    Joven, Jorge; Guirro, Maria; Mariné-Casadó, Roger; Rodríguez-Gallego, Esther; Menéndez, Javier A

    2014-01-01

    The inflammatory response is an energy-intensive process. Consequently, metabolism is closely associated with immune function. The autophagy machinery plays a role in metabolism by providing energy but may also be used to attack invading pathogens (xenophagy). The autophagy machinery may function to protect against not only the threats of infection but also the threats of the host's own response acting on the central immunological tolerance and the negative regulation of innate and inflammatory signaling. The balance between too little and too much autophagy is critical for the survival of immune cells because autophagy is linked to type 2-cell death programmed necrosis and apoptosis. Changes in inflammatory cells are driven by extracellular signals; however, the mechanisms by which cytokines mediate autophagy regulation and govern immune cell function remain unknown. Certain cytokines increase autophagy, whereas others inhibit autophagy. The relationship between autophagy and inflammation is also important in the pathogenesis of metabolic, non-communicable diseases. Inflammation per se is not the cause of obesity-associated diseases, but it is secondary to both the positive energy balance and the specific cellular responses. In metabolic tissues, the suppression of autophagy increases inflammation with the overexpression of cytokines, resulting in an activation of autophagy. The physiological role of these apparently contradictory findings remains uncertain but exemplifies future challenges in the therapeutic modulation of autophagy in the management of disease.

  1. Overexpression of KAI1 induces autophagy and increases MiaPaCa-2 cell survival through the phosphorylation of extracellular signal-regulated kinases

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Chun-Yan [State Key Laboratory of Cancer Biology and Institute of Digestive Diseases, Xijing Hospital of Digestive Disease, Fourth Military Medical University, Xi' an 710032 (China); Department of Gastroenterology, Shenyang General Hospital of PLA, 83 Wenhua Road, Shenyang 110016 (China); Yan, Jun; Yang, Yue-Feng; Xiao, Feng-Jun; Li, Qing-Fang; Zhang, Qun-Wei; Wang, Li-Sheng [Department of Experimental Hematology, Beijing Institute of Radiation Medicine, Beijing 100850 (China); Guo, Xiao-Zhong, E-mail: guoxiaozhong1962@163.com [Department of Gastroenterology, Shenyang General Hospital of PLA, 83 Wenhua Road, Shenyang 110016 (China); Wang, Hua, E-mail: wanghua@bmi.ac.cn [Department of Experimental Hematology, Beijing Institute of Radiation Medicine, Beijing 100850 (China)

    2011-01-21

    Research highlights: {yields} We first investigate the effects of KAI1 on autophagy in MiaPaCa-2 cells. {yields} Our findings demonstrate that KAI1 induces autophagy, which in turn inhibits KAI1-induced apoptosis. {yields} This study also supplies a possible novel therapeutic method for the treatment of pancreatic cancer using autophagy inhibitors. -- Abstract: KAI1, a metastasis-suppressor gene belonging to the tetraspanin family, is known to inhibit cancer metastasis without affecting the primary tumorigenicity by inhibiting the epidermal growth factor (EGF) signaling pathway. Recent studies have shown that hypoxic conditions of solid tumors induce high-level autophagy and KAI1 expression. However, the relationship between autophagy and KAI1 remains unclear. By using transmission electron microscopy, confocal microscopy, and Western blotting, we found that KAI1 can induce autophagy in a dose- and time-dependent manner in the human pancreatic cell line MiaPaCa-2. KAI1-induced autophagy was confirmed by the expression of autophagy-related proteins LC3 and Beclin 1. KAI1 induces autophagy through phosphorylation of extracellular signal-related kinases rather than that of AKT. KAI1-induced autophagy protects MiaPaCa-2 cells from apoptosis and proliferation inhibition partially through the downregulation of poly [adenosine diphosphate (ADP)-ribose] polymerase (PARP) cleavage and caspase-3 activation.

  2. Glucocorticoids Acutely Increase Brown Adipose Tissue Activity in Humans, Revealing Species-Specific Differences in UCP-1 Regulation.

    Science.gov (United States)

    Ramage, Lynne E; Akyol, Murat; Fletcher, Alison M; Forsythe, John; Nixon, Mark; Carter, Roderick N; van Beek, Edwin J R; Morton, Nicholas M; Walker, Brian R; Stimson, Roland H

    2016-07-12

    The discovery of brown adipose tissue (BAT) in adult humans presents a new therapeutic target for metabolic disease; however, little is known about the regulation of human BAT. Chronic glucocorticoid excess causes obesity in humans, and glucocorticoids suppress BAT activation in rodents. We tested whether glucocorticoids regulate BAT activity in humans. In vivo, the glucocorticoid prednisolone acutely increased (18)fluorodeoxyglucose uptake by BAT (measured using PET/CT) in lean healthy men during mild cold exposure (16°C-17°C). In addition, prednisolone increased supraclavicular skin temperature (measured using infrared thermography) and energy expenditure during cold, but not warm, exposure in lean subjects. In vitro, glucocorticoids increased isoprenaline-stimulated respiration and UCP-1 in human primary brown adipocytes, but substantially decreased isoprenaline-stimulated respiration and UCP-1 in primary murine brown and beige adipocytes. The highly species-specific regulation of BAT function by glucocorticoids may have important implications for the translation of novel treatments to activate BAT to improve metabolic health. PMID:27411014

  3. The Impact of Autophagy on Cell Death Modalities

    Directory of Open Access Journals (Sweden)

    Stefan W. Ryter

    2014-01-01

    Full Text Available Autophagy represents a homeostatic cellular mechanism for the turnover of organelles and proteins, through a lysosome-dependent degradation pathway. During starvation, autophagy facilitates cell survival through the recycling of metabolic precursors. Additionally, autophagy can modulate other vital processes such as programmed cell death (e.g., apoptosis, inflammation, and adaptive immune mechanisms and thereby influence disease pathogenesis. Selective pathways can target distinct cargoes (e.g., mitochondria and proteins for autophagic degradation. At present, the causal relationship between autophagy and various forms of regulated or nonregulated cell death remains unclear. Autophagy can occur in association with necrosis-like cell death triggered by caspase inhibition. Autophagy and apoptosis have been shown to be coincident or antagonistic, depending on experimental context, and share cross-talk between signal transduction elements. Autophagy may modulate the outcome of other regulated forms of cell death such as necroptosis. Recent advances suggest that autophagy can dampen inflammatory responses, including inflammasome-dependent caspase-1 activation and maturation of proinflammatory cytokines. Autophagy may also act as regulator of caspase-1 dependent cell death (pyroptosis. Strategies aimed at modulating autophagy may lead to therapeutic interventions for diseases in which apoptosis or other forms of regulated cell death may play a cardinal role.

  4. The Nuclear Zinc Finger Protein Zfat Maintains FoxO1 Protein Levels in Peripheral T Cells by Regulating the Activities of Autophagy and the Akt Signaling Pathway.

    Science.gov (United States)

    Ishikura, Shuhei; Iwaihara, Yuri; Tanaka, Yoko; Luo, Hao; Nishi, Kensuke; Doi, Keiko; Koyanagi, Midori; Okamura, Tadashi; Tsunoda, Toshiyuki; Shirasawa, Senji

    2016-07-15

    Forkhead box O1 (FoxO1) is a key molecule for the development and functions of peripheral T cells. However, the precise mechanisms regulating FoxO1 expression in peripheral T cells remain elusive. We previously reported that Zfat(f/f)-CD4Cre mice showed a marked decline in FoxO1 protein levels in peripheral T cells, partially through proteasomal degradation. Here we have identified the precise mechanisms, apart from proteasome-mediated degradation, of the decreased FoxO1 levels in Zfat-deficient T cells. First, we confirmed that tamoxifen-inducible deletion of Zfat in Zfat(f/f)-CreERT2 mice coincidently decreases FoxO1 protein levels in peripheral T cells, indicating that Zfat is essential for maintaining FoxO1 levels in these cells. Although the proteasome-specific inhibitors lactacystin and epoxomicin only moderately increase FoxO1 protein levels, the inhibitors of lysosomal proteolysis bafilomycin A1 and chloroquine restore the decreased FoxO1 levels in Zfat-deficient T cells to levels comparable with those in control cells. Furthermore, Zfat-deficient T cells show increased numbers of autophagosomes and decreased levels of p62 protein, together indicating that Zfat deficiency promotes lysosomal FoxO1 degradation through autophagy. In addition, Zfat deficiency increases the phosphorylation levels of Thr-308 and Ser-473 of Akt and the relative amounts of cytoplasmic to nuclear FoxO1 protein levels, indicating that Zfat deficiency causes Akt activation, leading to nuclear exclusion of FoxO1. Our findings have demonstrated a novel role of Zfat in maintaining FoxO1 protein levels in peripheral T cells by regulating the activities of autophagy and the Akt signaling pathway. PMID:27226588

  5. HIV-1 differentially modulates autophagy in neurons and astrocytes.

    Science.gov (United States)

    Mehla, Rajeev; Chauhan, Ashok

    2015-08-15

    Autophagy, a lysosomal degradative pathway that maintains cellular homeostasis, has emerged as an innate immune defense against pathogens. The role of autophagy in the deregulated HIV-infected central nervous system (CNS) is unclear. We have found that HIV-1-induced neuro-glial (neurons and astrocytes) damage involves modulation of the autophagy pathway. Neuro-glial stress induced by HIV-1 led to biochemical and morphological dysfunctions. X4 HIV-1 produced neuro-glial toxicity coupled with suppression of autophagy, while R5 HIV-1-induced toxicity was restricted to neurons. Rapamycin, a specific mTOR inhibitor (autophagy inducer) relieved the blockage of the autophagy pathway caused by HIV-1 and resulted in neuro-glial protection. Further understanding of the regulation of autophagy by cytokines and chemokines or other signaling events may lead to recognition of therapeutic targets for neurodegenerative diseases.

  6. Interleukin-1β regulates fat-liver crosstalk in obesity by auto-paracrine modulation of adipose tissue inflammation and expandability.

    Directory of Open Access Journals (Sweden)

    Ori Nov

    Full Text Available The inflammasome has been recently implicated in obesity-associated dys-metabolism. However, of its products, the specific role of IL-1β was clinically demonstrated to mediate only the pancreatic beta-cell demise, and in mice mainly the intra-hepatic manifestations of obesity. Yet, it remains largely unknown if IL-1β, a cytokine believed to mainly function locally, could regulate dysfunctional inter-organ crosstalk in obesity. Here we show that High-fat-fed (HFF mice exhibited a preferential increase of IL-1β in portal compared to systemic blood. Moreover, portally-drained mesenteric fat transplantation from IL-1βKO donors resulted in lower pyruvate-glucose flux compared to mice receiving wild-type (WT transplant. These results raised a putative endocrine function for visceral fat-derived IL-1β in regulating hepatic gluconeogenic flux. IL-1βKO mice on HFF exhibited only a minor or no increase in adipose expression of pro-inflammatory genes (including macrophage M1 markers, Mac2-positive crown-like structures and CD11b-F4/80-double-positive macrophages, all of which were markedly increased in WT-HFF mice. Further consistent with autocrine/paracrine functions of IL-1β within adipose tissue, adipose tissue macrophage lipid content was increased in WT-HFF mice, but significantly less in IL-1βKO mice. Ex-vivo, adipose explants co-cultured with primary hepatocytes from WT or IL-1-receptor (IL-1RI-KO mice suggested only a minor direct effect of adipose-derived IL-1β on hepatocyte insulin resistance. Importantly, although IL-1βKOs gained weight similarly to WT-HFF, they had larger fat depots with similar degree of adipocyte hypertrophy. Furthermore, adipogenesis genes and markers (pparg, cepba, fabp4, glut4 that were decreased by HFF in WT, were paradoxically elevated in IL-1βKO-HFF mice. These local alterations in adipose tissue inflammation and expansion correlated with a lower liver size, less hepatic steatosis, and preserved insulin

  7. Transcriptome profiling of brown adipose tissue during cold exposure reveals extensive regulation of glucose metabolism.

    Science.gov (United States)

    Hao, Qin; Yadav, Rachita; Basse, Astrid L; Petersen, Sidsel; Sonne, Si B; Rasmussen, Simon; Zhu, Qianhua; Lu, Zhike; Wang, Jun; Audouze, Karine; Gupta, Ramneek; Madsen, Lise; Kristiansen, Karsten; Hansen, Jacob B

    2015-03-01

    We applied digital gene expression profiling to determine the transcriptome of brown and white adipose tissues (BAT and WAT, respectively) during cold exposure. Male C57BL/6J mice were exposed to cold for 2 or 4 days. A notable induction of genes related to glucose uptake, glycolysis, glycogen metabolism, and the pentose phosphate pathway was observed in BAT from cold-exposed animals. In addition, glycerol-3-phosphate dehydrogenase 1 expression was induced in BAT from cold-challenged mice, suggesting increased synthesis of glycerol from glucose. Similarly, expression of lactate dehydrogenases was induced by cold in BAT. Pyruvate dehydrogenase kinase 2 (Pdk2) and Pdk4 were expressed at significantly higher levels in BAT than in WAT, and Pdk2 was induced in BAT by cold. Of notice, only a subset of the changes detected in BAT was observed in WAT. Based on changes in gene expression during cold exposure, we propose a model for the intermediary glucose metabolism in activated BAT: 1) fluxes through glycolysis and the pentose phosphate pathway are induced, the latter providing reducing equivalents for de novo fatty acid synthesis; 2) glycerol synthesis from glucose is increased, facilitating triacylglycerol synthesis/fatty acid re-esterification; 3) glycogen turnover and lactate production are increased; and 4) entry of glucose carbon into the tricarboxylic acid cycle is restricted by PDK2 and PDK4. In summary, our results demonstrate extensive and diverse gene expression changes related to glucose handling in activated BAT. PMID:25516548

  8. GPR30 regulates diet-induced adiposity in female mice and adipogenesis in vitro

    Science.gov (United States)

    Wang, Aihua; Luo, Jing; Moore, William; Alkhalidy, Hana; Wu, Ling; Zhang, Jinhua; Zhen, Wei; Wang, Yao; Clegg, Deborah J.; Bin Xu; Cheng, Zhiyong; McMillan, Ryan P.; Hulver, Matthew W.; Liu, Dongmin

    2016-01-01

    Recent studies showed that GPR30, a seven-transmembrane G-protein-coupled receptor, is a novel estrogen receptor (ER) that mediates some biological events elicited by estrogen in several types of cancer cells. However, its physiological or pathological role in vivo is unclear. Here, we show that GPR30 knockout (GPRKO) female mice were protected from high-fat diet (HFD)-induced obesity, blood glucose intolerance, and insulin resistance. The decreased body weight gain in GPRKO female mice is due to the reduction in body fat mass. These effects occurred in the absence of significant changes in food intake, intestinal fat absorption, triglyceride metabolism, or energy expenditure. However, GPR30 had no significant metabolic effects in male mice fed the HFD and both sexes of mice fed a chow diet. Further, GPR30 expression levels in fat tissues of WT obese female mice were greatly increased, whereas ERα and β expression was not altered. Deletion of GPR30 reduced adipogenic differentiation of adipose tissue-derived stromal cells. Conversely, activation of GPR30 enhanced adipogenic differentiation of 3T3-L1 preadipocytes. These findings provide evidence for the first time that GPR30 promotes adipogenesis and therefore the development of obesity in female mice exposed to excess fat energy. PMID:27698362

  9. 自噬与甲状腺癌的研究进展%Autophagy and its research progress in thyroid cancer

    Institute of Scientific and Technical Information of China (English)

    张思林; 罗庆; 余杰情

    2016-01-01

    To summarize the autophagy and its research progress in thyroid cancer.In combination with available literatures published in recent years involving the relationship between autophagy and thyroid cancer,the characteristics of autophagy,the role in thyroid cancer were reviewed.The changes of autophagy level will directly or indirectly participate in the pathogenesis and progression of thyroid cancer.Reagents regulating autophagy will have broad prospect of application in thyroid cancer therapy.The autophagy in the thyroid cancer is still poorly understood,and to clarify the molecular mechanism of autophagy and kill thyroid cancer cells by reasonable regulation of autophagy still needs more further studies.

  10. 白色脂肪棕色化及其调控因素%Browning of white adipose tissue and its regulating factors

    Institute of Scientific and Technical Information of China (English)

    吕丹; 陈树春; 李晓思

    2014-01-01

    Recently,great progress has been achieved in the understanding of the origin,differentiation,function,and regulation of adipose tissue.While white adipose tissue in the body is responsible for storing energy and secreting adipocytokines which involved in various metabolic diseases,brown adipose tissue is mainly responsible for producing heat and energy consumption.So ‘browning of white adipose tissue’ has great potential to be used in the treatment of obesity and many related diseases,which can provide new options for the treatment of these diseases in the future.The process of ‘browning of white adipose tissue’ is regulated by many factors,such as a variety of transcriptional regulators,proteins and hormones,so new intervention method may be achieved by targeting these regulatory factors.%近年,对脂肪组织的起源、分化、作用及调节的认识有了新的进展.体内的白色脂肪组织负责储存能量并分泌一些脂肪因子参与各种代谢性疾病的发生,而棕色脂肪组织主要负责产热和消耗能量.因此,“白色脂肪棕色化”对肥胖及许多相关疾病有着巨大的治疗潜力,可为这些疾病的治疗提供新的选择.“白色脂肪棕色化”这一过程受多种因素调控,如多种转录调节剂、蛋白质和激素等,因此未来可通过干预这些调控因素来研究相关疾病的新治疗方法.

  11. Epigenetic modifications as regulatory elements of autophagy in cancer.

    Science.gov (United States)

    Sui, Xinbing; Zhu, Jing; Zhou, Jichun; Wang, Xian; Li, Da; Han, Weidong; Fang, Yong; Pan, Hongming

    2015-05-01

    Epigenetic modifications have been considered as hallmarks of cancer and play an important role in tumor initiation and development. Epigenetic mechanisms, including DNA methylation, histone modifications, and microRNAs, may regulate cell cycle and apoptosis, as well as macroautophagy (hereafter referred to as autophagy). Autophagy, as a crucial cellular homeostatic mechanism, performs a dual role, having pro-survival or pro-death properties. A variety of signaling pathways including epigenetic control have been implicated in the upregulation or downregulation of autophagy. However, the role of epigenetic regulation in autophagy is still less well acknowledged. Recent studies have linked epigenetic control to the autophagic process. Some epigenetic modifiers are also involved in the regulation of autophagy and potentiate the efficacy of traditional therapeutics. Thus, understanding the novel functions of epigenetic control in autophagy may allow us to develop potential therapeutic approaches for cancer treatment.

  12. Midazolam regulated caspase pathway, endoplasmic reticulum stress, autophagy, and cell cycle to induce apoptosis in MA-10 mouse Leydig tumor cells

    Directory of Open Access Journals (Sweden)

    So EC

    2016-04-01

    Full Text Available Edmund Cheung So,1,2 Yung-Chia Chen,3 Shu-Chun Wang,4 Chia-Ching Wu,4 Man-Chi Huang,4 Meng-Shao Lai,4 Bo-Syong Pan,4,5 Fu-Chi Kang,6 Bu-Miin Huang4 1Department of Anesthesia, An Nan Hospital, China Medical University, Tainan, Taiwan, Republic of China; 2Department of Anesthesia, School of Medicine, China Medical University, Taichung, Taiwan; Republic of China; 3Department of Anatomy, School of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Republic of China; 4Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China; 5Department of Cancer Biology, Wake Forest University School of Medicine, Winston Salem, NC, USA; 6Department of Anesthesia, Chi Mei Medical Center, Chiali, Tainan, Taiwan, Republic of China Purpose: Midazolam is widely used as a sedative and anesthetic induction agent by modulating the different GABA receptors in the central nervous system. Studies have also shown that midazolam has an anticancer effect on various tumors. In a previous study, we found that midazolam could induce MA-10 mouse Leydig tumor cell apoptosis by activating caspase cascade. However, the detailed mechanism related to the upstream and downstream pathways of the caspase cascade, such as endoplasmic reticulum (ER stress, autophagy, and p53 pathways plus cell cycle regulation in MA-10 mouse Leydig tumor cells, remains elusive.Methods: Flow cytometry assay and Western blot analyses were exploited.Results: Midazolam significantly decreased cell viability but increased sub-G1 phase cell numbers in MA-10 cells (P<0.05. Annexin V/propidium iodide double staining further confirmed that midazolam induced apoptosis. In addition, expressions of Fas and Fas ligand could be detected in MA-10 cells with midazolam treatments, and Bax translocation and cytochrome c release were also involved in midazolam-induced MA-10 cell apoptosis. Moreover, the staining and expression of LC3-II proteins could

  13. De Novo Reconstruction of Adipose Tissue Transcriptomes Reveals Long Non-coding RNA Regulators of Brown Adipocyte Development.

    Science.gov (United States)

    Alvarez-Dominguez, Juan R; Bai, Zhiqiang; Xu, Dan; Yuan, Bingbing; Lo, Kinyui Alice; Yoon, Myeong Jin; Lim, Yen Ching; Knoll, Marko; Slavov, Nikolai; Chen, Shuai; Chen, Peng; Lodish, Harvey F; Sun, Lei

    2015-05-01

    Brown adipose tissue (BAT) protects against obesity by promoting energy expenditure via uncoupled respiration. To uncover BAT-specific long non-coding RNAs (lncRNAs), we used RNA-seq to reconstruct de novo transcriptomes of mouse brown, inguinal white, and epididymal white fat and identified ∼1,500 lncRNAs, including 127 BAT-restricted loci induced during differentiation and often targeted by key regulators PPARγ, C/EBPα, and C/EBPβ. One of them, lnc-BATE1, is required for establishment and maintenance of BAT identity and thermogenic capacity. lnc-BATE1 inhibition impairs concurrent activation of brown fat and repression of white fat genes and is partially rescued by exogenous lnc-BATE1 with mutated siRNA-targeting sites, demonstrating a function in trans. We show that lnc-BATE1 binds heterogeneous nuclear ribonucleoprotein U and that both are required for brown adipogenesis. Our work provides an annotated catalog for the study of fat depot-selective lncRNAs and establishes lnc-BATE1 as a regulator of BAT development and physiology.

  14. Developmental, hormonal, and nutritional regulation of expression of porcine adipose tissue triglyceride lipase (pATGL) gene

    Science.gov (United States)

    Adipose triglyceride lipase (ATGL) is a newly identified lipase. We report for the first time the porcine ATGL sequence and characterize ATGL gene and protein expression in vitro and in vivo. Adult pig tissue expresses ATGL at high levels in the white adipose and muscle tissue relative to other te...

  15. Autophagy, Metabolism, and Cancer.

    Science.gov (United States)

    White, Eileen; Mehnert, Janice M; Chan, Chang S

    2015-11-15

    Macroautophagy (autophagy hereafter) captures intracellular proteins and organelles and degrades them in lysosomes. The degradation breakdown products are released from lysosomes and recycled into metabolic and biosynthetic pathways. Basal autophagy provides protein and organelle quality control by eliminating damaged cellular components. Starvation-induced autophagy recycles intracellular components into metabolic pathways to sustain mitochondrial metabolic function and energy homeostasis. Recycling by autophagy is essential for yeast and mammals to survive starvation through intracellular nutrient scavenging. Autophagy suppresses degenerative diseases and has a context-dependent role in cancer. In some models, cancer initiation is suppressed by autophagy. By preventing the toxic accumulation of damaged protein and organelles, particularly mitochondria, autophagy limits oxidative stress, chronic tissue damage, and oncogenic signaling, which suppresses cancer initiation. This suggests a role for autophagy stimulation in cancer prevention, although the role of autophagy in the suppression of human cancer is unclear. In contrast, some cancers induce autophagy and are dependent on autophagy for survival. Much in the way that autophagy promotes survival in starvation, cancers can use autophagy-mediated recycling to maintain mitochondrial function and energy homeostasis to meet the elevated metabolic demand of growth and proliferation. Thus, autophagy inhibition may be beneficial for cancer therapy. Moreover, tumors are more autophagy-dependent than normal tissues, suggesting that there is a therapeutic window. Despite these insights, many important unanswered questions remain about the exact mechanisms of autophagy-mediated cancer suppression and promotion, how relevant these observations are to humans, and whether the autophagy pathway can be modulated therapeutically in cancer. See all articles in this CCR Focus section, "Cell Death and Cancer Therapy."

  16. Crosstalk of clock gene expression and autophagy in aging

    Science.gov (United States)

    Kalfalah, Faiza; Janke, Linda; Schiavi, Alfonso; Tigges, Julia; Ix, Alexander; Ventura, Natascia; Boege, Fritz; Reinke, Hans

    2016-01-01

    Autophagy and the circadian clock counteract tissue degeneration and support longevity in many organisms. Accumulating evidence indicates that aging compromises both the circadian clock and autophagy but the mechanisms involved are unknown. Here we show that the expression levels of transcriptional repressor components of the circadian oscillator, most prominently the human Period homologue PER2, are strongly reduced in primary dermal fibroblasts from aged humans, while raising the expression of PER2 in the same cells partially restores diminished autophagy levels. The link between clock gene expression and autophagy is corroborated by the finding that the circadian clock drives cell-autonomous, rhythmic autophagy levels in immortalized murine fibroblasts, and that siRNA-mediated downregulation of PER2 decreases autophagy levels while leaving core clock oscillations intact. Moreover, the Period homologue lin-42 regulates autophagy and life span in the nematode Caenorhabditis elegans, suggesting an evolutionarily conserved role for Period proteins in autophagy control and aging. Taken together, this study identifies circadian clock proteins as set-point regulators of autophagy and puts forward a model, in which age-related changes of clock gene expression promote declining autophagy levels. PMID:27574892

  17. Primary cilia: the chemical antenna regulating human adipose-derived stem cell osteogenesis.

    Directory of Open Access Journals (Sweden)

    Josephine C Bodle

    Full Text Available Adipose-derived stem cells (ASC are multipotent stem cells that show great potential as a cell source for osteogenic tissue replacements and it is critical to understand the underlying mechanisms of lineage specification. Here we explore the role of primary cilia in human ASC (hASC differentiation. This study focuses on the chemosensitivity of the primary cilium and the action of its associated proteins: polycystin-1 (PC1, polycystin-2 (PC2 and intraflagellar transport protein-88 (IFT88, in hASC osteogenesis. To elucidate cilia-mediated mechanisms of hASC differentiation, siRNA knockdown of PC1, PC2 and IFT88 was performed to disrupt cilia-associated protein function. Immunostaining of the primary cilium structure indicated phenotypic-dependent changes in cilia morphology. hASC cultured in osteogenic differentiation media yielded cilia of a more elongated conformation than those cultured in expansion media, indicating cilia-sensitivity to the chemical environment and a relationship between the cilium structure and phenotypic determination. Abrogation of PC1, PC2 and IFT88 effected changes in both hASC proliferation and differentiation activity, as measured through proliferative activity, expression of osteogenic gene markers, calcium accretion and endogenous alkaline phosphatase activity. Results indicated that IFT88 may be an early mediator of the hASC differentiation process with its knockdown increasing hASC proliferation and decreasing Runx2, alkaline phosphatase and BMP-2 mRNA expression. PC1 and PC2 knockdown affected later osteogenic gene and end-product expression. PC1 knockdown resulted in downregulation of alkaline phosphatase and osteocalcin gene expression, diminished calcium accretion and reduced alkaline phosphatase enzymatic activity. Taken together our results indicate that the structure of the primary cilium is intimately associated with the process of hASC osteogenic differentiation and that its associated proteins are critical

  18. Hypoxia, MTOR and autophagy

    OpenAIRE

    Blagosklonny, Mikhail V.

    2013-01-01

    Although hypoxia can cause cell cycle arrest, it may simultaneously suppress a conversion from this arrest to senescence. Furthermore, hypoxia can suppress senescence caused by diverse stimuli, maintaining reversible quiescence instead. Hypoxia activates autophagy and inhibits MTOR, thus also activating autophagy. What is the relationship between autophagy and cellular senescence? Also, can inhibition of MTOR and stimulation of autophagy explain the gerosuppressive effects of hypoxia?

  19. Autophagy modulation as a target for anticancer drug discovery

    Institute of Scientific and Technical Information of China (English)

    Xin LI; Huai-long XU; Yong-xi LIU; Na AN; Si ZHAO; Jin-ku BAO

    2013-01-01

    Autophagy,an evolutionarily conserved catabolic process involving the engulfment and degradation of non-essential or abnormal cellular organelles and proteins,is crucial for homeostatic maintenance in living cells.This highly regulated,multi-step process has been implicated in diverse diseases including cancer.Autophagy can function as either a promoter or a suppressor of cancer,which makes it a promising and challenging therapeutic target.Herein,we overview the regulatory mechanisms and dual roles of autophagy in cancer.We also describe some of the representative agents that exert their anticancer effects by regulating autophagy.Additionally,some emerging strategies aimed at modulating autophagy are discussed as having the potential for future anticancer drug discovery.In summary,these findings will provide valuable information to better utilize autophagy in the future development of anticancer therapeutics that meet clinical requirements.

  20. Regulation of G0/G1 switch gene 2 (G0S2) expression in human adipose tissue.

    Science.gov (United States)

    Skopp, Alexander; May, Marcus; Janke, Juergen; Kielstein, Heike; Wunder, Ruth; Flade-Kuthe, Ricarda; Kuthe, Andreas; Jordan, Jens; Engeli, Stefan

    2016-05-01

    The G0/G1 switch gene 2 (G0S2) protein attenuated adipose triglyceride lipase (ATGL) activity and decreased lipolysis in rodent and human adipocytes. We hypothesized that G0S2 mRNA expression in human adipose tissue is influenced by depot, adipocyte size, body weight and caloric intake. Adipose tissue samples were obtained during abdominal surgery and by needle biopsy before and 3 h after an extended glucose load in lean subjects. G0S2 mRNA was 7× higher expressed in mature human adipocytes compared to the stromavascular fraction. Cell size inversely correlated with G0S2 mRNA expression in both, subcutaneous and omental adipose depots. G0S2 mRNA expression was 75% higher in subcutaneous compared to omental adipose tissue. Obesity was associated with lower G0S2 mRNA expression in subcutaneous adipose tissue. Acute glucose ingestion after an overnight fast did not significantly increase G0S2 expression in subcutaneous adipose tissue. In conclusion, differences in G0S2 expression may explain depot-specific and obesity-associated differences in lipolysis on the molecular level. PMID:26707160

  1. Mechanisms of mitochondria and autophagy crosstalk

    OpenAIRE

    Rambold, Angelika S.; Lippincott-Schwartz, Jennifer

    2011-01-01

    Autophagy is a cellular survival pathway that recycles intracellular components to compensate for nutrient depletion and ensures the appropriate degradation of organelles. Mitochondrial number and health are regulated by mitophagy, a process by which excessive or damaged mitochondria are subjected to autophagic degradation. Autophagy is thus a key determinant for mitochondrial health and proper cell function. Mitophagic malfunction has been recently proposed to contribute to progressive neuro...

  2. Autophagy in lung disease pathogenesis and therapeutics

    OpenAIRE

    Ryter, Stefan W.; Augustine M K Choi

    2015-01-01

    Autophagy, a cellular pathway for the degradation of damaged organelles and proteins, has gained increasing importance in human pulmonary diseases, both as a modulator of pathogenesis and as a potential therapeutic target. In this pathway, cytosolic cargos are sequestered into autophagosomes, which are delivered to the lysosomes where they are enzymatically degraded and then recycled as metabolic precursors. Autophagy exerts an important effector function in the regulation of inflammation, an...

  3. Identification of a novel phosphorylation site in adipose triglyceride lipase as a regulator of lipid droplet localization.

    Science.gov (United States)

    Xie, Xitao; Langlais, Paul; Zhang, Xiaodong; Heckmann, Bradlee L; Saarinen, Alicia M; Mandarino, Lawrence J; Liu, Jun

    2014-06-15

    Adipose triglyceride lipase (ATGL), the rate-limiting enzyme for triacylglycerol (TG) hydrolysis, has long been known to be a phosphoprotein. However, the potential phosphorylation events that are involved in the regulation of ATGL function remain incompletely defined. Here, using a combinatorial proteomics approach, we obtained evidence that at least eight different sites of ATGL can be phosphorylated in adipocytes. Among them, Thr³⁷² resides within the hydrophobic region known to mediate lipid droplet (LD) targeting. Although it had no impact on the TG hydrolase activity, substitution of phosphorylation-mimic Asp for Thr³⁷² eliminated LD localization and LD-degrading capacity of ATGL expressed in HeLa cells. In contrast, mutation of Thr³⁷² to Ala gave a protein that bound LDs and functioned the same as the wild-type protein. In nonstimulated adipocytes, the Asp mutation led to decreased LD association and basal lipolytic activity of ATGL, whereas the Ala mutation produced opposite effects. Moreover, the LD translocation of ATGL upon β-adrenergic stimulation was also compromised by the Asp mutation. In accord with these findings, the Ala mutation promoted and the Asp mutation attenuated the capacity of ATGL to mediate lipolysis in adipocytes under both basal and stimulated conditions. Collectively, these studies identified Thr³⁷² as a novel phosphorylation site that may play a critical role in determining subcellular distribution as well as lipolytic action of ATGL.

  4. Identification of a novel phosphorylation site in adipose triglyceride lipase as a regulator of lipid droplet localization.

    Science.gov (United States)

    Xie, Xitao; Langlais, Paul; Zhang, Xiaodong; Heckmann, Bradlee L; Saarinen, Alicia M; Mandarino, Lawrence J; Liu, Jun

    2014-06-15

    Adipose triglyceride lipase (ATGL), the rate-limiting enzyme for triacylglycerol (TG) hydrolysis, has long been known to be a phosphoprotein. However, the potential phosphorylation events that are involved in the regulation of ATGL function remain incompletely defined. Here, using a combinatorial proteomics approach, we obtained evidence that at least eight different sites of ATGL can be phosphorylated in adipocytes. Among them, Thr³⁷² resides within the hydrophobic region known to mediate lipid droplet (LD) targeting. Although it had no impact on the TG hydrolase activity, substitution of phosphorylation-mimic Asp for Thr³⁷² eliminated LD localization and LD-degrading capacity of ATGL expressed in HeLa cells. In contrast, mutation of Thr³⁷² to Ala gave a protein that bound LDs and functioned the same as the wild-type protein. In nonstimulated adipocytes, the Asp mutation led to decreased LD association and basal lipolytic activity of ATGL, whereas the Ala mutation produced opposite effects. Moreover, the LD translocation of ATGL upon β-adrenergic stimulation was also compromised by the Asp mutation. In accord with these findings, the Ala mutation promoted and the Asp mutation attenuated the capacity of ATGL to mediate lipolysis in adipocytes under both basal and stimulated conditions. Collectively, these studies identified Thr³⁷² as a novel phosphorylation site that may play a critical role in determining subcellular distribution as well as lipolytic action of ATGL. PMID:24801391

  5. AMP-Activated Kinase Regulates Lipid Droplet Localization and Stability of Adipose Triglyceride Lipase in C. elegans Dauer Larvae.

    Directory of Open Access Journals (Sweden)

    Meng Xie

    Full Text Available Animals have developed diverse mechanisms to adapt to their changing environment. Like many organisms the free-living nematode C. elegans can alternate between a reproductive mode or a diapause-like "dauer" stage during larval development to circumvent harsh environmental conditions. The master metabolic regulator AMP-activated protein kinase (AMPK is critical for survival during the dauer stage, where it phosphorylates adipose triglyceride lipase (ATGL-1 at multiple sites to block lipid hydrolysis and ultimately protect the cellular triglyceride-based energy depot from rapid depletion. However, how the AMPK-mediated phosphorylation affects the function of ATGL-1 has not been characterised at the molecular level. Here we show that AMPK phosphorylation leads to the generation of 14-3-3 binding sites on ATGL-1, which are recognized by the C. elegans 14-3-3 protein orthologue PAR-5. Physical interaction of ATGL-1 with PAR-5 results in sequestration of ATGL-1 away from the lipid droplets and eventual proteasome-mediated degradation. In addition, we also show that the major AMPK phosphorylation site on ATGL-1, Ser 303, is required for both modification of its lipid droplet localization and its degradation. Our data provide mechanistic insight as to how AMPK functions to enhance survival through its ability to protect the accumulated triglyceride deposits from rapid hydrolysis to preserve the energy stores during periods of extended environmental duress.

  6. Rph1 mediates the nutrient-limitation signaling pathway leading to transcriptional activation of autophagy.

    Science.gov (United States)

    Bernard, Amélie; Klionsky, Daniel J

    2015-04-01

    To maintain proper cellular homeostasis, the magnitude of autophagy activity has to be finely tuned in response to environmental changes. Many aspects of autophagy regulation have been extensively studied: pathways integrating signals through the master regulators TORC1 and PKA lead to multiple post-translational modifications affecting the functions, protein-protein interactions, and localization of Atg proteins. The expression of several ATG genes increases sharply upon autophagy induction conditions, and defects in ATG gene expression are associated with various diseases, pointing to the importance of transcriptional regulation of autophagy. Yet, how changes in ATG gene expression affect the rate of autophagy is not well characterized, and transcriptional regulators of the autophagy pathway remain largely unknown. To identify such regulators, we analyzed the expression of several ATG genes in a library of DNA-binding protein mutants. This led to the identification of Rph1 as a master transcriptional regulator of autophagy.

  7. Nutrigenomic regulation of adipose tissue development - role of retinoic acid: A review.

    Science.gov (United States)

    Wang, Bo; Yang, Qiyuan; Harris, Corrine L; Nelson, Mark L; Busboom, Jan R; Zhu, Mei-Jun; Du, Min

    2016-10-01

    To improve the efficiency of animal production, livestock have been extensively selected or managed to reduce fat accumulation and increase lean growth, which reduces intramuscular or marbling fat content. To enhance marbling, a better understanding of the mechanisms regulating adipogenesis is needed. Vitamin A has recently been shown to have a profound impact on all stages of adipogenesis. Retinoic acid, an active metabolite of vitamin A, activates both retinoic acid receptors (RAR) and retinoid X receptors (RXR), inducing epigenetic changes in key regulatory genes governing adipogenesis. Additionally, Vitamin D and folates interact with the retinoic acid receptors to regulate adipogenesis. In this review, we discuss nutritional regulation of adipogenesis, focusing on retinoic acid and its impact on epigenetic modifications of key adipogenic genes. PMID:27086067

  8. Autophagy: for better or for worse

    Institute of Scientific and Technical Information of China (English)

    Ellen Wirawan; Tom Vanden Berghe; Saskia Lippens; Patrizia Agostinis; Peter Vandenabeele

    2012-01-01

    Autophagy is a lysosomal degradation pathway that degrades damaged or superfluous cell components into basic biomolecules,which are then recycled back into the cytosol.In this respect,autophagy drives a flow of biomolecules in a continuous degradation-regeneration cycle.Autophagy is generally considered a pro-survival mechanism protecting cells under stress or poor nutrient conditions.Current research clearly shows that autophagy fulfills numerous functions in vital biological processes.It is implicated in development,differentiation,innate and adaptive immunity,ageing and cell death.In addition,accumulating evidence demonstrates interesting links between autophagy and several human diseases and tumor development.Therefore,autophagy seems to be an important player in the life and death of cells and organisms.Despite the mounting knowledge about autophagy,the mechanisms through which the autophagic machinery regulates these diverse processes are not entirely understood.In this review,we give a comprehensive overview of the autophagic signaling pathway,its role in general cellular processes and its connection to cell death.In addition,we present a brief overview of the possible contribution of defective autophagic signaling to disease.

  9. Autophagy in Mycobacterium tuberculosis and HIV infections

    Directory of Open Access Journals (Sweden)

    Lucile eEspert

    2015-06-01

    Full Text Available Human Immunodeficiency Virus (HIV and Mycobacterium tuberculosis (M.tb are among the most lethal human pathogens worldwide, each being responsible for around 1.5 million deaths annually. Moreover, synergy between acquired immune deficiency syndrome (AIDS and tuberculosis (TB has turned HIV/M.tb co-infection into a major public health threat in developing countries. In the past decade, autophagy, a lysosomal catabolic process, has emerged as a major host immune defense mechanism against infectious agents like M.tb and HIV. Nevertheless, in some instances, autophagy machinery appears to be instrumental for HIV infection. Finally, there is mounting evidence that both pathogens deploy various countermeasures to thwart autophagy. This mini-review proposes an overview of the roles and regulations of autophagy in HIV and M.tb infections with an emphasis on microbial factors. We also discuss the role of autophagy manipulation in the context of HIV/M.tb co-infection. In future, a comprehensive understanding of autophagy interaction with these pathogens will be critical for development of autophagy-based prophylactic and therapeutic interventions for AIDS and TB.

  10. WASH inhibits autophagy through suppression of Beclin 1 ubiquitination

    OpenAIRE

    Xia, Pengyan; Wang, Shuo; Du, Ying; Zhao, Zhenao; Shi, Lei; Sun, Lei; Huang, Guanling; Ye, Buqing; Li, Chong; Dai, Zhonghua; Hou, Ning; Cheng, Xuan; Sun, Qingyuan; Li, Lei(Beijing Institute of Petrochemical Technology, Beijing, 102617, People's Republic of China); Yang, Xiao

    2013-01-01

    Autophagy degrades cytoplasmic proteins and organelles to recycle cellular components that are required for cell survival and tissue homeostasis. However, it is not clear how autophagy is regulated in mammalian cells. WASH (Wiskott–Aldrich syndrome protein (WASP) and SCAR homologue) plays an essential role in endosomal sorting through facilitating tubule fission via Arp2/3 activation. Here, we demonstrate a novel function of WASH in modulation of autophagy. We show that WASH deficiency causes...

  11. Autophagy and mitophagy in the myocardium: therapeutic potential and concerns

    OpenAIRE

    Jimenez, Rebecca E; Kubli, Dieter A.; Gustafsson, Åsa B.

    2014-01-01

    The autophagic-lysosomal degradation pathway is critical for cardiac homeostasis, and defects in this pathway are associated with development of cardiomyopathy. Autophagy is responsible for the normal turnover of organelles and long-lived proteins. Autophagy is also rapidly up-regulated in response to stress, where it rapidly clears dysfunctional organelles and cytotoxic protein aggregates in the cell. Autophagy is also important in clearing dysfunctional mitochondria before they can cause ha...

  12. RUFY4: Immunity piggybacking on autophagy?

    Science.gov (United States)

    Terawaki, Seigo; Camosseto, Voahirana; Pierre, Philippe; Gatti, Evelina

    2016-01-01

    Although autophagy is a highly conserved mechanism among species and cell types, few are the molecules involved with the autophagic process that display cell- or tissue- specific expression. We have unraveled the positive regulatory role on autophagy of RUFY4 (RUN and FYVE domain containing 4), which is expressed in subsets of immune cells, including dendritic cells (DCs). DCs orchestrate the eradication of pathogens by coordinating the action of the different cell types involved in microbe recognition and destruction during the immune response. To fulfill this function, DC display particular regulation of their endocytic and autophagy pathways in response to the immune environment. Autophagy flux is downmodulated in DCs upon microbe sensing, but is remarkably augmented, when cells are differentiated in the presence of the pleiotropic cytokine IL4 (interleukin 4). From gene expression studies aimed at comparing the impact of IL4 on DC differentiation, we identified RUFY4, as a novel regulator that augments autophagy flux and, when overexpressed, induces drastic membrane redistribution and strongly tethers lysosomes. RUFY4 is therefore one of the few known positive regulators of autophagy that is expressed in a cell-specific manner or under specific immunological conditions associated with IL4 expression such as allergic asthma.

  13. Autophagy in stem and progenitor cells.

    Science.gov (United States)

    Rodolfo, Carlo; Di Bartolomeo, Sabrina; Cecconi, Francesco

    2016-02-01

    Autophagy is a highly conserved cellular process, responsible for the degradation and recycling of damaged and/or outlived proteins and organelles. This is the major cellular pathway, acting throughout the formation of cytosolic vesicles, called autophagosomes, for the delivering to lysosome. Recycling of cellular components through autophagy is a crucial step for cell homeostasis as well as for tissue remodelling during development. Impairment of this process has been related to the pathogenesis of various diseases, such as cancer and neurodegeneration, to the response to bacterial and viral infections, and to ageing. The ability of stem cells to self-renew and differentiate into the mature cells of the body renders this unique type of cell highly crucial to development and tissue renewal, not least in various diseases. During the last two decades, extensive knowledge about autophagy roles and regulation in somatic cells has been acquired; however, the picture about the role and the regulation of autophagy in the different types of stem cells is still largely unknown. Autophagy is a major player in the quality control and maintenance of cellular homeostasis, both crucial factors for stem cells during an organism's life. In this review, we have highlighted the most significant advances in the comprehension of autophagy regulation in embryonic and tissue stem cells, as well as in cancer stem cells and induced pluripotent cells.

  14. CD44 plays a critical role in regulating diet-induced adipose inflammation, hepatic steatosis, and insulin resistance.

    Directory of Open Access Journals (Sweden)

    Hong Soon Kang

    Full Text Available CD44 is a multifunctional membrane receptor implicated in the regulation of several biological processes, including inflammation. CD44 expression is elevated in liver and white adipose tissue (WAT during obesity suggesting a possible regulatory role for CD44 in metabolic syndrome. To study this hypothesis, we examined the effect of the loss of CD44 expression on the development of various features of metabolic syndrome using CD44 null mice. Our study demonstrates that CD44-deficient mice (CD44KO exhibit a significantly reduced susceptibility to the development of high fat-diet (HFD-induced hepatic steatosis, WAT-associated inflammation, and insulin resistance. The decreased expression of genes involved in fatty acid synthesis and transport (Fasn and Cd36, de novo triglyceride synthesis (Mogat1, and triglyceride accumulation (Cidea, Cidec appears in part responsible for the reduced hepatic lipid accumulation in CD44KO(HFD mice. In addition, the expression of various inflammatory and cell matrix genes, including several chemokines and its receptors, osteopontin, and several matrix metalloproteinases and collagen genes was greatly diminished in CD44KO(HFD liver consistent with reduced inflammation and fibrogenesis. In contrast, lipid accumulation was significantly increased in CD44KO(HFD WAT, whereas inflammation as indicated by the reduced infiltration of macrophages and expression of macrophage marker genes, was significantly diminished in WAT of CD44KO(HFD mice compared to WT(HFD mice. CD44KO(HFD mice remained considerably more insulin sensitive and glucose tolerant than WT(HFD mice and exhibited lower blood insulin levels. Our study indicates that CD44 plays a critical role in regulating several aspects of metabolic syndrome and may provide a new therapeutic target in the management of insulin resistance.

  15. Determinants of human adipose tissue gene expression: impact of diet, sex, metabolic status, and cis genetic regulation.

    Directory of Open Access Journals (Sweden)

    Nathalie Viguerie

    2012-09-01

    Full Text Available Weight control diets favorably affect parameters of the metabolic syndrome and delay the onset of diabetic complications. The adaptations occurring in adipose tissue (AT are likely to have a profound impact on the whole body response as AT is a key target of dietary intervention. Identification of environmental and individual factors controlling AT adaptation is therefore essential. Here, expression of 271 transcripts, selected for regulation according to obesity and weight changes, was determined in 515 individuals before, after 8-week low-calorie diet-induced weight loss, and after 26-week ad libitum weight maintenance diets. For 175 genes, opposite regulation was observed during calorie restriction and weight maintenance phases, independently of variations in body weight. Metabolism and immunity genes showed inverse profiles. During the dietary intervention, network-based analyses revealed strong interconnection between expression of genes involved in de novo lipogenesis and components of the metabolic syndrome. Sex had a marked influence on AT expression of 88 transcripts, which persisted during the entire dietary intervention and after control for fat mass. In women, the influence of body mass index on expression of a subset of genes persisted during the dietary intervention. Twenty-two genes revealed a metabolic syndrome signature common to men and women. Genetic control of AT gene expression by cis signals was observed for 46 genes. Dietary intervention, sex, and cis genetic variants independently controlled AT gene expression. These analyses help understanding the relative importance of environmental and individual factors that control the expression of human AT genes and therefore may foster strategies aimed at improving AT function in metabolic diseases.

  16. The Role of AKT/mTOR Pathway in Stress Response to UV-Irradiation: Implication in Skin Carcinogenesis by Regulation of Apoptosis, Autophagy and Senescence

    Directory of Open Access Journals (Sweden)

    Elwira Strozyk

    2013-07-01

    Full Text Available Induction of DNA damage by UVB and UVA radiation may generate mutations and genomic instability leading to carcinogenesis. Therefore, skin cells being repeatedly exposed to ultraviolet (UV light have acquired multilayered protective mechanisms to avoid malignant transformation. Besides extensive DNA repair mechanisms, the damaged skin cells can be eliminated by induction of apoptosis, which is mediated through the action of tumor suppressor p53. In order to prevent the excessive loss of skin cells and to maintain the skin barrier function, apoptotic pathways are counteracted by anti-apoptotic signaling including the AKT/mTOR pathway. However, AKT/mTOR not only prevents cell death, but is also active in cell cycle transition and hyper-proliferation, thereby also counteracting p53. In turn, AKT/mTOR is tuned down by the negative regulators being controlled by the p53. This inhibition of AKT/mTOR, in combination with transactivation of damage-regulated autophagy modulators, guides the p53-mediated elimination of damaged cellular components by autophagic clearance. Alternatively, p53 irreversibly blocks cell cycle progression to prevent AKT/mTOR-driven proliferation, thereby inducing premature senescence. Conclusively, AKT/mTOR via an extensive cross talk with p53 influences the UV response in the skin with no black and white scenario deciding over death or survival.

  17. Autophagy in Tuberculosis

    Science.gov (United States)

    Deretic, Vojo

    2014-01-01

    Autophagy as an immune mechanism controls inflammation and acts as a cell-autonomous defense against intracellular microbes including Mycobacterium tuberculosis. An equally significant role of autophagy is its anti-inflammatory and tissue-sparing function. This combination of antimicrobial and anti-inflammatory actions prevents active disease in animal models. In human populations, genetic links between autophagy, inflammatory bowel disease, and susceptibility to tuberculosis provide further support to these combined roles of autophagy. The autophagic control of M. tuberculosis and prevention of progressive disease provide novel insights into physiological and immune control of tuberculosis. It also offers host-based therapeutic opportunities because autophagy can be pharmacologically modulated. PMID:25167980

  18. Regulation of Nutrient Metabolism in Equine Skeletal Muscle and Adipose Tissue

    OpenAIRE

    Suagee, Jessica Kanekakenre

    2010-01-01

    Glucose and lipid metabolism are dysregulated in obese horses. Altered glucose metabolism is evidenced by the development of insulin resistance and increased fasting plasma insulin concentrations (hyperinsulinemia) while altered lipid metabolism is evidenced by increased plasma lipid concentrations. Obesity in horses also increases the risk of the painful hoof disease, laminitis. Three experiments were performed to investigate the regulation of nutrient metabolism in skeletal muscle and adip...

  19. Steroid biosynthesis in adipose tissue.

    Science.gov (United States)

    Li, Jiehan; Papadopoulos, Vassilios; Vihma, Veera

    2015-11-01

    Tissue-specific expression of steroidogenic enzymes allows the modulation of active steroid levels in a local manner. Thus, the measurement of local steroid concentrations, rather than the circulating levels, has been recognized as a more accurate indicator of the steroid action within a specific tissue. Adipose tissue, one of the largest endocrine tissues in the human body, has been established as an important site for steroid storage and metabolism. Locally produced steroids, through the enzymatic conversion from steroid precursors delivered to adipose tissue, have been proven to either functionally regulate adipose tissue metabolism, or quantitatively contribute to the whole body's steroid levels. Most recently, it has been suggested that adipose tissue may contain the steroidogenic machinery necessary for the initiation of steroid biosynthesis de novo from cholesterol. This review summarizes the evidence indicating the presence of the entire steroidogenic apparatus in adipose tissue and discusses the potential roles of local steroid products in modulating adipose tissue activity and other metabolic parameters.

  20. Adipose tissue mTORC2 regulates ChREBP-driven de novo lipogenesis and hepatic glucose metabolism

    Science.gov (United States)

    Tang, Yuefeng; Wallace, Martina; Sanchez-Gurmaches, Joan; Hsiao, Wen-Yu; Li, Huawei; Lee, Peter L.; Vernia, Santiago; Metallo, Christian M.; Guertin, David A.

    2016-01-01

    Adipose tissue de novo lipogenesis (DNL) positively influences insulin sensitivity, is reduced in obesity, and predicts insulin resistance. Therefore, elucidating mechanisms controlling adipose tissue DNL could lead to therapies for type 2 diabetes. Here, we report that mechanistic target of rapamycin complex 2 (mTORC2) functions in white adipose tissue (WAT) to control expression of the lipogenic transcription factor ChREBPβ. Conditionally deleting the essential mTORC2 subunit Rictor in mature adipocytes decreases ChREBPβ expression, which reduces DNL in WAT, and impairs hepatic insulin sensitivity. Mechanistically, Rictor/mTORC2 promotes ChREBPβ expression in part by controlling glucose uptake, but without impairing pan-AKT signalling. High-fat diet also rapidly decreases adipose tissue ChREBPβ expression and insulin sensitivity in wild-type mice, and does not further exacerbate insulin resistance in adipose tissue Rictor knockout mice, implicating adipose tissue DNL as an early target in diet-induced insulin resistance. These data suggest mTORC2 functions in WAT as part of an extra-hepatic nutrient-sensing mechanism to control glucose homeostasis. PMID:27098609

  1. The DUB-ious lack of ALIS in Salmonella infection: a Salmonella deubiquitinase regulates the autophagy of protein aggregates.

    Science.gov (United States)

    Thomas, Mair; Mesquita, Francisco S; Holden, David W

    2012-12-01

    Ubiquitinated aggregates are formed in eukaryotic cells in response to several external stimuli, including exposure to bacterial lipopolysaccharide (LPS). Although Salmonella enterica serovar Typhimurium (S. Typhimurium) LPS has been shown to induce aggresome-like induced structures (ALIS) in macrophages, these have not been described in S. Typhimurium-infected macrophages. Given that LPS is present in infection, this suggests that S. Typhimurium might suppress the formation of ALIS. We found that S. Typhimurium induces the formation of ubiquitinated aggregates in epithelial cells and macrophages, but that their presence is masked by the deubiquitinase (DUB) activity of the S. Typhimurium virulence protein, SseL. SseL deubiquitinates SQSTM1/p62-bound proteins found in S. Typhimurium-induced aggregates and ALIS, and reduces the recruitment of autophagic components. While the functions of ALIS and other ubiquitinated aggregates remain unclear, they serve to sequester cytosolic proteins under a variety of stress conditions and are suggested to be involved in host immune defense. During infection, the deubiquitinase activity of SseL reduces autophagic flux in infected cells and favors bacterial replication. This is a new example of how a bacterial pathogen counteracts the autophagy pathway through the action of a translocated virulence protein.

  2. miR-487b-5p Regulates Temozolomide Resistance of Lung Cancer Cells Through LAMP2-Medicated Autophagy.

    Science.gov (United States)

    Bao, Liang; Lv, Lei; Feng, Jinping; Chen, Yuyu; Wang, Xinhua; Han, Shuguang; Zhao, Hongqing

    2016-08-01

    Temozolomide (TMZ) is a standard agent used in the treatment of various types of cancers, including lung carcinoma, but TMZ resistance is common and accounts for many treatment failures. We investigated miRNA-487b-5p (miR-487b-5p) was highly expressed in A549 and H1299 cells which acquired TMZ resistance. Suppression of miR-487b-5p had overt effects on cellular proliferation and migration in the presence of TMZ. On the other hand, knockdown of miR-487b-5p resulted in increased survival and moderate tumor growth in vivo. In addition, the decreased cellular proliferation following miR-487b-5p suppression was linked to enhanced autophagy, evident by drastically increased levels of LC3-II, BECLIN1, and LAMP2 when miR-487b-5p was knocked down. Further analysis revealed that LAMP2 might be the target gene of miR-487b-5p. In conclusion, our study suggested that miR-487b-5p may be a potential biomarker of acquired TMZ resistance in lung cancer cells, and miR-487b-5p inhibition can be further explored as a chemotherapy target in the treatment of TMZ-resistant lung carcinoma.

  3. Beyond glycolysis: GAPDHs are multi-functional enzymes involved in regulation of ROS, autophagy, and plant immune responses.

    Directory of Open Access Journals (Sweden)

    Elizabeth Henry

    2015-04-01

    Full Text Available Glyceraldehyde-3-phosphate dehydrogenase (GAPDH is an important enzyme in energy metabolism with diverse cellular regulatory roles in vertebrates, but few reports have investigated the importance of plant GAPDH isoforms outside of their role in glycolysis. While animals possess one GAPDH isoform, plants possess multiple isoforms. In this study, cell biological and genetic approaches were used to investigate the role of GAPDHs during plant immune responses. Individual Arabidopsis GAPDH knockouts (KO lines exhibited enhanced disease resistance phenotypes upon inoculation with the bacterial plant pathogen Pseudomonas syringae pv. tomato. KO lines exhibited accelerated programmed cell death and increased electrolyte leakage in response to effector triggered immunity. Furthermore, KO lines displayed increased basal ROS accumulation as visualized using the fluorescent probe H2DCFDA. The gapa1-2 and gapc1 KOs exhibited constitutive autophagy phenotypes in the absence of nutrient starvation. Due to the high sequence conservation between vertebrate and plant cytosolic GAPDH, our experiments focused on cytosolic GAPC1 cellular dynamics using a complemented GAPC1-GFP line. Confocal imaging coupled with an endocytic membrane marker (FM4-64 and endosomal trafficking inhibitors (BFA, Wortmannin demonstrated cytosolic GAPC1 is localized to the plasma membrane and the endomembrane system, in addition to the cytosol and nucleus. After perception of bacterial flagellin, GAPC1 dynamically responded with a significant increase in size of fluorescent puncta and enhanced nuclear accumulation. Taken together, these results indicate that plant GAPDHs can affect multiple aspects of plant immunity in diverse sub-cellular compartments.

  4. Beyond glycolysis: GAPDHs are multi-functional enzymes involved in regulation of ROS, autophagy, and plant immune responses.

    Science.gov (United States)

    Henry, Elizabeth; Fung, Nicholas; Liu, Jun; Drakakaki, Georgia; Coaker, Gitta

    2015-04-01

    Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is an important enzyme in energy metabolism with diverse cellular regulatory roles in vertebrates, but few reports have investigated the importance of plant GAPDH isoforms outside of their role in glycolysis. While animals possess one GAPDH isoform, plants possess multiple isoforms. In this study, cell biological and genetic approaches were used to investigate the role of GAPDHs during plant immune responses. Individual Arabidopsis GAPDH knockouts (KO lines) exhibited enhanced disease resistance phenotypes upon inoculation with the bacterial plant pathogen Pseudomonas syringae pv. tomato. KO lines exhibited accelerated programmed cell death and increased electrolyte leakage in response to effector triggered immunity. Furthermore, KO lines displayed increased basal ROS accumulation as visualized using the fluorescent probe H2DCFDA. The gapa1-2 and gapc1 KOs exhibited constitutive autophagy phenotypes in the absence of nutrient starvation. Due to the high sequence conservation between vertebrate and plant cytosolic GAPDH, our experiments focused on cytosolic GAPC1 cellular dynamics using a complemented GAPC1-GFP line. Confocal imaging coupled with an endocytic membrane marker (FM4-64) and endosomal trafficking inhibitors (BFA, Wortmannin) demonstrated cytosolic GAPC1 is localized to the plasma membrane and the endomembrane system, in addition to the cytosol and nucleus. After perception of bacterial flagellin, GAPC1 dynamically responded with a significant increase in size of fluorescent puncta and enhanced nuclear accumulation. Taken together, these results indicate that plant GAPDHs can affect multiple aspects of plant immunity in diverse sub-cellular compartments. PMID:25918875

  5. Autophagy modulates articular cartilage vesicle formation in primary articular chondrocytes.

    Science.gov (United States)

    Rosenthal, Ann K; Gohr, Claudia M; Mitton-Fitzgerald, Elizabeth; Grewal, Rupinder; Ninomiya, James; Coyne, Carolyn B; Jackson, William T

    2015-05-22

    Chondrocyte-derived extracellular organelles known as articular cartilage vesicles (ACVs) participate in non-classical protein secretion, intercellular communication, and pathologic calcification. Factors affecting ACV formation and release remain poorly characterized; although in some cell types, the generation of extracellular vesicles is associated with up-regulation of autophagy. We sought to determine the role of autophagy in ACV production by primary articular chondrocytes. Using an innovative dynamic model with a light scatter nanoparticle counting apparatus, we determined the effects of autophagy modulators on ACV number and content in conditioned medium from normal adult porcine and human osteoarthritic chondrocytes. Healthy articular chondrocytes release ACVs into conditioned medium and show significant levels of ongoing autophagy. Rapamycin, which promotes autophagy, increased ACV numbers in a dose- and time-dependent manner associated with increased levels of autophagy markers and autophagosome formation. These effects were suppressed by pharmacologic autophagy inhibitors and short interfering RNA for ATG5. Caspase-3 inhibition and a Rho/ROCK inhibitor prevented rapamycin-induced increases in ACV number. Osteoarthritic chondrocytes, which are deficient in autophagy, did not increase ACV number in response to rapamycin. SMER28, which induces autophagy via an mTOR-independent mechanism, also increased ACV number. ACVs induced under all conditions had similar ecto-enzyme specific activities and types of RNA, and all ACVs contained LC3, an autophagosome-resident protein. These findings identify autophagy as a critical participant in ACV formation, and augment our understanding of ACVs in cartilage disease and repair.

  6. PPARγ and MyoD are differentially regulated by myostatin in adipose-derived stem cells and muscle satellite cells

    International Nuclear Information System (INIS)

    Myostatin (MSTN) is a secreted protein belonging to the transforming growth factor-β (TGF-β) family that is primarily expressed in skeletal muscle and also functions in adipocyte maturation. Studies have shown that MSTN can inhibit adipogenesis in muscle satellite cells (MSCs) but not in adipose-derived stem cells (ADSCs). However, the mechanism by which MSTN differently regulates adipogenesis in these two cell types remains unknown. Peroxisome proliferator-activated receptor-γ (PPARγ) and myogenic differentiation factor (MyoD) are two key transcription factors in fat and muscle cell development that influence adipogenesis. To investigate whether MSTN differentially regulates PPARγ and MyoD, we analyzed PPARγ and MyoD expression by assessing mRNA, protein and methylation levels in ADSCs and MSCs after treatment with 100 ng/mL MSTN for 0, 24, and 48 h. PPARγ mRNA levels were downregulated after 24 h and upregulated after 48 h of treatment in ADSCs, whereas in MSCs, PPARγ levels were downregulated at both time points. MyoD expression was significantly increased in ADSCs and decreased in MSCs. PPARγ and MyoD protein levels were upregulated in ADSCs and downregulated in MSCs. The CpG methylation levels of the PPARγ and MyoD promoters were decreased in ADSCs and increased in MSCs. Therefore, this study demonstrated that the different regulatory adipogenic roles of MSTN in ADSCs and MSCs act by differentially regulating PPARγ and MyoD expression. - Highlights: • PPARγ and MyoD mRNA and protein levels are upregulated by myostatin in ADSCs. • PPARγ and MyoD mRNA and protein levels are downregulated by myostatin in MSCs. • PPARγ exhibited different methylation levels in myostatin-treated ADSCs and MSCs. • MyoD exhibited different methylation levels in myostatin-treated ADSCs and MSCs. • PPARγ and MyoD are differentially regulated by myostatin in ADSCs and MSCs

  7. PPARγ and MyoD are differentially regulated by myostatin in adipose-derived stem cells and muscle satellite cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Feng [Key Laboratory of Swine Genetics and Breeding of the Agricultural Ministry and Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of the Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070 (China); Deng, Bing [Wuhan Institute of Animal Science and Veterinary Medicine, Wuhan Academy of Agricultural Science and Technology, Wuhan, Hubei, 430208 (China); Wen, Jianghui [Wu Han University of Technology, Wuhan 430074 (China); Chen, Kun [Key Laboratory of Swine Genetics and Breeding of the Agricultural Ministry and Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of the Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070 (China); Liu, Wu; Ye, Shengqiang; Huang, Haijun [Wuhan Institute of Animal Science and Veterinary Medicine, Wuhan Academy of Agricultural Science and Technology, Wuhan, Hubei, 430208 (China); Jiang, Siwen, E-mail: jiangsiwen@mail.hzau.edu.cn [Key Laboratory of Swine Genetics and Breeding of the Agricultural Ministry and Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of the Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070 (China); Xiong, Yuanzhu, E-mail: xiongyzhu@163.com [Key Laboratory of Swine Genetics and Breeding of the Agricultural Ministry and Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of the Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070 (China)

    2015-03-06

    Myostatin (MSTN) is a secreted protein belonging to the transforming growth factor-β (TGF-β) family that is primarily expressed in skeletal muscle and also functions in adipocyte maturation. Studies have shown that MSTN can inhibit adipogenesis in muscle satellite cells (MSCs) but not in adipose-derived stem cells (ADSCs). However, the mechanism by which MSTN differently regulates adipogenesis in these two cell types remains unknown. Peroxisome proliferator-activated receptor-γ (PPARγ) and myogenic differentiation factor (MyoD) are two key transcription factors in fat and muscle cell development that influence adipogenesis. To investigate whether MSTN differentially regulates PPARγ and MyoD, we analyzed PPARγ and MyoD expression by assessing mRNA, protein and methylation levels in ADSCs and MSCs after treatment with 100 ng/mL MSTN for 0, 24, and 48 h. PPARγ mRNA levels were downregulated after 24 h and upregulated after 48 h of treatment in ADSCs, whereas in MSCs, PPARγ levels were downregulated at both time points. MyoD expression was significantly increased in ADSCs and decreased in MSCs. PPARγ and MyoD protein levels were upregulated in ADSCs and downregulated in MSCs. The CpG methylation levels of the PPARγ and MyoD promoters were decreased in ADSCs and increased in MSCs. Therefore, this study demonstrated that the different regulatory adipogenic roles of MSTN in ADSCs and MSCs act by differentially regulating PPARγ and MyoD expression. - Highlights: • PPARγ and MyoD mRNA and protein levels are upregulated by myostatin in ADSCs. • PPARγ and MyoD mRNA and protein levels are downregulated by myostatin in MSCs. • PPARγ exhibited different methylation levels in myostatin-treated ADSCs and MSCs. • MyoD exhibited different methylation levels in myostatin-treated ADSCs and MSCs. • PPARγ and MyoD are differentially regulated by myostatin in ADSCs and MSCs.

  8. Autophagy in Inflammatory Diseases

    Directory of Open Access Journals (Sweden)

    Alexander J. S. Choi

    2011-01-01

    Full Text Available Autophagy provides a mechanism for the turnover of cellular organelles and proteins through a lysosome-dependent degradation pathway. During starvation, autophagy exerts a homeostatic function that promotes cell survival by recycling metabolic precursors. Additionally, autophagy can interact with other vital processes such as programmed cell death, inflammation, and adaptive immune mechanisms, and thereby potentially influence disease pathogenesis. Macrophages deficient in autophagic proteins display enhanced caspase-1-dependent proinflammatory cytokine production and the activation of the inflammasome. Autophagy provides a functional role in infectious diseases and sepsis by promoting intracellular bacterial clearance. Mutations in autophagy-related genes, leading to loss of autophagic function, have been implicated in the pathogenesis of Crohn's disease. Furthermore, autophagy-dependent mechanisms have been proposed in the pathogenesis of several pulmonary diseases that involve inflammation, including cystic fibrosis and pulmonary hypertension. Strategies aimed at modulating autophagy may lead to therapeutic interventions for diseases associated with inflammation.

  9. MicroRNA 21 regulates the proliferation of human adipose tissue-derived mesenchymal stem cells and high-fat diet-induced obesity alters microRNA 21 expression in white adipose tissues.

    Science.gov (United States)

    Kim, Yeon Jeong; Hwang, Soo Hyun; Cho, Hyun Hwa; Shin, Keun Koo; Bae, Yong Chan; Jung, Jin Sup

    2012-01-01

    A better understanding of the molecular mechanisms that govern human adipose tissue-derived mesenchymal stem cells (hASCs) differentiation could provide new insights into a number of diseases including obesity. Our previous study demonstrated that microRNA-21 (miR-21) controls the adipogenic differentiation of hASCs. In this study, we determined the expression of miR-21 in white adipose tissues in a high-fat diet (HFD)-induced obesity mouse model to examine the relationship between miR-21 and obesity and the effect of miR-21 on hASCs proliferation. Our study showed biphasic changes of miR-21 expression and a correlation between miR-21 level and adipocyte number in the epididymal fat of HFD mice. Over-expression of miR-21 decreased cell proliferation, whereas inhibiting miR-21 with 2'-O-methyl-antisense RNA increased it. Over-expression of miR-21 decreased both protein and mRNA levels of STAT3, whereas inhibiting miR-21 with 2'-O-methyl-antisense RNA increased these levels. The activity of a luciferase construct containing the miR-21 target site from the STAT3 3'UTR was lower in LV-miR21-infected hASCs than in LV-miLacZ infected cells. RNA interference-mediated down-regulation of STAT3 decreased cell proliferation without affecting adipogenic differentiation. These findings provide the evidence of the correlation between miR-21 level and adipocyte number in the white adipose tissue of HFD-induced obese mice, which provides new insights into the mechanisms of obesity.

  10. Globular Adiponectin Causes Tolerance to LPS-Induced TNF-α Expression via Autophagy Induction in RAW 264.7 Macrophages: Involvement of SIRT1/FoxO3A Axis.

    Science.gov (United States)

    Pun, Nirmala Tilija; Subedi, Amit; Kim, Mi Jin; Park, Pil-Hoon

    2015-01-01

    Adiponectin, an adipokine predominantly produced from adipose tissue, exhibited potent anti-inflammatory properties. In particular, it inhibits production of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), in macrophages. Autophagy, an intracellular self-digestion process, has been recently shown to regulate inflammatory responses. In the present study, we investigated the role of autophagy induction in the suppression of Lipopolysaccharide (LPS) -induced TNF-α expression by globular adiponectin (gAcrp) and its potential mechanisms. Herein, we found that gAcrp treatment increased expression of genes related with autophagy, including Atg5 and microtubule-associated protein light chain (LC3B), induced autophagosome formation and autophagy flux in RAW 264.7 macrophages. Similar results were observed in primary macrophages isolated peritoneum of mice. Interestingly, inhibition of autophagy by pretreatment with Bafilomycin A1 or knocking down of LC3B gene restored suppression of TNF-α expression, tumor necrosis factor receptor- associated factor 6 (TRAF6) expression and p38MAPK phosphorylation by gAcrp, implying a critical role of autophagy induction in the development of tolerance to LPS-induced TNF-α expression by gAcrp. We also found that knocking-down of FoxO3A, a forkhead box O member of transcription factor, blocked gAcrp-induced expression of LC3II and Atg5. Moreover, gene silencing of Silent information regulator 1 (SIRT1) blocked both gAcrp-induced nuclear translocation of FoxO3A and LC3II expression. Finally, pretreatment with ROS inhibitors, prevented gAcrp-induced SIRT1 expression and further generated inhibitory effects on gAcrp-induced autophagy, indicating a role of ROS production in gAcrp-induced SIRT1 expression and subsequent autophagy induction. Taken together, these findings indicate that globular adiponectin suppresses LPS-induced TNF-α expression, at least in part, via autophagy activation. Furthermore, SIRT1-FoxO3A

  11. Globular Adiponectin Causes Tolerance to LPS-Induced TNF-α Expression via Autophagy Induction in RAW 264.7 Macrophages: Involvement of SIRT1/FoxO3A Axis.

    Science.gov (United States)

    Pun, Nirmala Tilija; Subedi, Amit; Kim, Mi Jin; Park, Pil-Hoon

    2015-01-01

    Adiponectin, an adipokine predominantly produced from adipose tissue, exhibited potent anti-inflammatory properties. In particular, it inhibits production of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), in macrophages. Autophagy, an intracellular self-digestion process, has been recently shown to regulate inflammatory responses. In the present study, we investigated the role of autophagy induction in the suppression of Lipopolysaccharide (LPS) -induced TNF-α expression by globular adiponectin (gAcrp) and its potential mechanisms. Herein, we found that gAcrp treatment increased expression of genes related with autophagy, including Atg5 and microtubule-associated protein light chain (LC3B), induced autophagosome formation and autophagy flux in RAW 264.7 macrophages. Similar results were observed in primary macrophages isolated peritoneum of mice. Interestingly, inhibition of autophagy by pretreatment with Bafilomycin A1 or knocking down of LC3B gene restored suppression of TNF-α expression, tumor necrosis factor receptor- associated factor 6 (TRAF6) expression and p38MAPK phosphorylation by gAcrp, implying a critical role of autophagy induction in the development of tolerance to LPS-induced TNF-α expression by gAcrp. We also found that knocking-down of FoxO3A, a forkhead box O member of transcription factor, blocked gAcrp-induced expression of LC3II and Atg5. Moreover, gene silencing of Silent information regulator 1 (SIRT1) blocked both gAcrp-induced nuclear translocation of FoxO3A and LC3II expression. Finally, pretreatment with ROS inhibitors, prevented gAcrp-induced SIRT1 expression and further generated inhibitory effects on gAcrp-induced autophagy, indicating a role of ROS production in gAcrp-induced SIRT1 expression and subsequent autophagy induction. Taken together, these findings indicate that globular adiponectin suppresses LPS-induced TNF-α expression, at least in part, via autophagy activation. Furthermore, SIRT1-FoxO3A

  12. Proteasome inhibition-induced p38 MAPK/ERK signaling regulates autophagy and apoptosis through the dual phosphorylation of glycogen synthase kinase 3{beta}

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Cheol-Hee [Research Center for Resistant Cells, Chosun University, Seosuk-dong, Dong-gu, Gwangju 501-759 (Korea, Republic of); Department of Pharmacology, College of Medicine, Chosun University, Seosuk-dong, Dong-gu, Gwangju 501-759 (Korea, Republic of); Lee, Byung-Hoon [College of Pharmacy and Multiscreening Center for Drug Development, Seoul National University, Seoul 151-742 (Korea, Republic of); Ahn, Sang-Gun [Department of Pathology, College of Dentistry, Chosun University, Gwangju 501-759 (Korea, Republic of); Oh, Seon-Hee, E-mail: oshccw@hanmail.net [Research Center for Resistant Cells, Chosun University, Seosuk-dong, Dong-gu, Gwangju 501-759 (Korea, Republic of)

    2012-02-24

    Highlights: Black-Right-Pointing-Pointer MG132 induces the phosphorylation of GSK3{beta}{sup Ser9} and, to a lesser extent, of GSK3{beta}{sup Thr390}. Black-Right-Pointing-Pointer MG132 induces dephosphorylation of p70S6K{sup Thr389} and phosphorylation of p70S6K{sup Thr421/Ser424}. Black-Right-Pointing-Pointer Inactivation of p38 dephosphorylates GSK3{beta}{sup Ser9} and phosphorylates GSK3{beta}{sup Thr390}. Black-Right-Pointing-Pointer Inactivation of p38 phosphorylates p70S6K{sup Thr389} and increases the phosphorylation of p70S6K{sup Thr421/Ser424}. Black-Right-Pointing-Pointer Inactivation of p38 decreases autophagy and increases apoptosis induced by MG132. -- Abstract: Proteasome inhibition is a promising approach for cancer treatment; however, the underlying mechanisms involved have not been fully elucidated. Here, we show that proteasome inhibition-induced p38 mitogen-activated protein kinase regulates autophagy and apoptosis by modulating the phosphorylation status of glycogen synthase kinase 3{beta} (GSK3{beta}) and 70 kDa ribosomal S6 kinase (p70S6K). The treatment of MDA-MB-231 cells with MG132 induced endoplasmic reticulum stress through the induction of ATF6a, PERK phosphorylation, and CHOP, and apoptosis through the cleavage of Bax and procaspase-3. MG132 caused the phosphorylation of GSK3{beta} at Ser{sup 9} and, to a lesser extent, Thr{sup 390}, the dephosphorylation of p70S6K at Thr{sup 389}, and the phosphorylation of p70S6K at Thr{sup 421} and Ser{sup 424}. The specific p38 inhibitor SB203080 reduced the p-GSK3{beta}{sup Ser9} and autophagy through the phosphorylation of p70S6K{sup Thr389}; however, it augmented the levels of p-ERK, p-GSK3{beta}{sup Thr390}, and p-70S6K{sup Thr421/Ser424} induced by MG132, and increased apoptotic cell death. The GSK inhibitor SB216763, but not lithium, inhibited the MG132-induced phosphorylation of p38, and the downstream signaling pathway was consistent with that in SB203580-treated cells. Taken together, our

  13. Inflammation, Autophagy, and Obesity: Common Features in the Pathogenesis of Pancreatitis and Pancreatic Cancer

    OpenAIRE

    Gukovsky, Ilya; Ning LI; Todoric, Jelena; Gukovskaya, Anna; Karin, Michael

    2013-01-01

    Inflammation and autophagy are cellular defense mechanisms. When these processes are deregulated (deficient or overactivated) they produce pathologic effects, such as oxidative stress, metabolic impairments, and cell death. Unresolved inflammation and disrupted regulation of autophagy are common features of pancreatitis and pancreatic cancer. Furthermore, obesity, a risk factor for pancreatitis and pancreatic cancer, promotes inflammation and inhibits or deregulates autophagy, creating an env...

  14. A Sensitive IHC Method for Monitoring Autophagy-Specific Markers in Human Tumor Xenografts.

    Science.gov (United States)

    He, Helen; Yang, Yu; Xiang, Zhongmin; Yu, Lunyin; Chouitar, Jouhara; Yu, Jie; D'Amore, Natalie Roy; Li, Ping; Li, Zhi; Bowman, Douglas; Theisen, Matthew; Brownell, James E; Tirrell, Stephen

    2016-01-01

    Objective. Use of tyramide signal amplification (TSA) to detect autophagy biomarkers in formalin fixed and paraffin embedded (FFPE) xenograft tissue. Materials and Methods. Autophagy marker regulation was studied in xenograft tissues using Amp HQ IHC and standard IHC methods. Results. The data demonstrate the feasibility of using high sensitivity TSA IHC assays to measure low abundant autophagy markers in FFPE xenograft tissue. PMID:27247826

  15. Research Progression of Cellular Autophagy in Liver System Diseases

    Institute of Scientific and Technical Information of China (English)

    Liu Chunyun; Gong Xiangwen; Xiao Xinfa; Yuan Xiangying

    2013-01-01

    Autophagy is a basic biological phenomenon widely existed in eukaryotic cells and an important mechanism for cells to adjust to the surrounding environment, prevent invasion of pathogenic micro-organisms and maintain homeostasis, whose activity changes evidently in multiple liver system diseases, suggesting that there is close association between autophagy and the generation and development of liver system diseases. It is also reported that autophagy develops and exerts an important function in many liver-related diseases, such as hepatic carcinoma, non-alcoholic fatty liver disease, alcoholic liver disease, viral liver disease and acute liver injury. Therefore, this study aimed to summarize the relationship between autophagy and multiple liver diseases, hoping to explore the effect of autophagy in liver system diseases and further study the regulative effect of autophagy so as to provide new thoughts for their treatment.

  16. Influence of Autophagy Regulation Agent on the Proliferation of Toxoplasma Gondii in Mice%自噬调控剂对小鼠体内弓形虫增殖的影响

    Institute of Scientific and Technical Information of China (English)

    张琼; 张婧; 高劲松; 李万峰; 汪学龙

    2016-01-01

    Objective:To study the influence of autophagy regulation agent on the proliferation of toxo-plasma gondii in mice.Methods:Using autophagy inhibitors bafilomycin A1 and autophagy iinducing agent lithium chloride respectively to intervene toxoplasma gondii infected mice.Fluorescence quantitative PCR was used to detect proliferation of Toxoplasma gondii under different experimental conditions.Results:Quantita-tive PCR results showed that bafilomycin A1 dose and the number of toxoplasma gondii in mice was negative correlated,while inducing agent lithium chloride and the number of toxoplasma gondii in mice was positive correlated.Conclusion:The regulation on autophagy of host cells in mice could regulate the proliferation and replication of toxoplasma gondii.%目的::研究自噬调控剂对小鼠体内弓形虫增殖的影响。方法:建立弓形虫感染的小鼠模型,分别使用自噬抑制剂巴弗洛霉 A1(bafilomycin A1)和自噬诱导剂氯化锂对弓形虫感染小鼠模型进行干预,应用荧光定量 PCR 检测不同实验条件下弓形虫数量。结果:实验结果表明巴弗洛霉素 A1剂量与小鼠体内弓形虫数量呈负相关,而诱导剂氯化锂与小鼠体内弓形虫数量呈正相关。结论:调控宿主细胞自噬可调控体内弓形虫增殖。

  17. Altered gut microbiota and endocannabinoid system tone in obese and diabetic leptin-resistant mice: impact on apelin regulation in adipose tissue

    Directory of Open Access Journals (Sweden)

    Lucie eGeurts

    2011-07-01

    Full Text Available Growing evidence supports the role of gut microbiota in the development of obesity, type 2 diabetes and low-grade inflammation. The endocrine activity of adipose tissue has been found to contribute to the regulation of glucose homeostasis and low-grade inflammation. Among the key hormones produced by this tissue, apelin has been shown to regulate glucose homeostasis. Recently, it has been proposed that gut microbiota participate in adipose tissue metabolism via the endocannabinoid system and gut microbiota-derived compounds, namely lipopolysaccharide (LPS. We have investigated gut microbiota composition in obese and diabetic leptin-resistant mice (db/db by combining pyrosequencing and phylogenetic microarray analysis of 16S ribosomal RNA gene sequences. We observed a significant higher abundance of Firmicutes, Proteobacteria and Fibrobacteres phyla in db/db mice compared to lean mice. The abundance of 10 genera was significantly affected by the genotype. We identified the roles of the endocannabinoid system and LPS in the regulation of apelinergic system tone (apelin and APJ mRNA expression in genetic obese and diabetic mice. By using in vivo and in vitro models, we have demonstrated that both the endocannabinoid system and low-grade inflammation differentially regulate apelin and APJ mRNA expression in adipose tissue. Finally, deep-gut microbiota profiling revealed that the gut microbial community of type 2 diabetic mice is significantly different from that of their lean counterparts. This indicates specific relationships between the gut microbiota and the regulation of the apelinergic system. However, the exact roles of specific bacteria in shaping the phenotype of db/db mice remain to be determined.

  18. Application and interpretation of current autophagy inhibitors and activators

    Institute of Scientific and Technical Information of China (English)

    Ya-ping YANG; Li-fang HU; Hui-fen ZHENG; Cheng-jie MAO; Wei-dong HU; Kang-ping XIONG; Fen WANG

    2013-01-01

    Aut ophagy is the major intracellular degradation system,by which cytoplasmic materials are delivered to and degraded in the lysosome.As a quality control mechanism for cytoplasmic proteins and organelles,autophagy plays important roles in a variety of human diseases,including neurodegenerative diseases,cancer,cardiovascular disease,diabetes and infectious and inflammatory diseases.The discovery of ATG genes and the dissection of the signaling pathways involved in regulating autophagy have greatly enriched our knowledge on the occurrence and development of this lysosomal degradation pathway.In addition to its role in degradation,autophagy may also promote a type of programmed cell death that is different from apoptosis,termed type II programmed cell death.Owing to the dual roles of autophagy in cell death and the specificity of diseases,the exact mechanisms of autophagy in various diseases require more investigation.The application of autophagy inhibitors and activators will help us understand the regulation of autophagy in human diseases,and provide insight into the use of autophagy-targeted drugs.In this review,we summarize the latest research on autophagy inhibitors and activators and discuss the possibility of their application in human disease therapy.

  19. Autophagy is required for IL-2-mediated fibroblast growth

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Rui [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15219 (United States); Tang, Daolin, E-mail: tangd2@upmc.edu [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15219 (United States); Lotze, Michael T., E-mail: lotzemt@upcm.edu [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15219 (United States); Zeh III, Herbert J., E-mail: zehh@upmc.edu [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15219 (United States)

    2013-02-15

    Autophagy is an evolutionarily conserved pathway responsible for delivery of cytoplasmic material into the lysosomal degradation pathway to enable vesicular exocytosis. Interleukin (IL)-2 is produced by T-cells and its activity is important for immunoregulation. Fibroblasts are an immune competent cell type, playing a critical role in wound healing, chronic inflammation, and tumor development. Although autophagy plays an important role in each of these processes, whether it regulates IL-2 activity in fibroblasts is unknown. Here, we show that autophagy is required for IL-2-induced cell growth in fibroblasts. IL-2 significantly induced autophagy in mouse embryonic fibroblasts (MEFs) and primary lung fibroblasts. Autophagy inhibitors (e.g., 3-methylamphetamine and bafilomycin A1) or knockdown of ATG5 and beclin 1 blocked clinical grade IL-2-induced autophagy. Moreover, IL-2 induced HMGB1 cytoplasmic translocation in MEFs and promoted interaction between HMGB1 and beclin1, which is required for autophagy induction. Pharmacological and genetic inhibition of autophagy inhibited IL-2-induced cell proliferation and enhanced IL-2-induced apoptosis. These findings suggest that autophagy is an important pro-survival regulator for IL-2-induced cell growth in fibroblasts.

  20. Sestrin2, a regulator of thermogenesis and mitohormesis in brown adipose tissue

    Directory of Open Access Journals (Sweden)

    Seung-Hyun eRo

    2015-07-01

    Full Text Available Sestrin2 is a stress-inducible protein that functions as an antioxidant and inhibitor of mTOR complex 1. In a recent study, we found that Sestrin2 overexpression in brown adipocytes interfered with normal metabolism by reducing mitochondrial respiration through the suppression of uncoupling protein 1 (UCP1 expression. The metabolic effects of Sestrin2 in brown adipocytes were dependent on its antioxidant activity, and chemical antioxidants produced similar effects in inhibiting UCP1-dependent thermogenesis. These observations suggest that low levels of ROS in brown adipocytes can actually be beneficial and necessary for proper metabolic homeostasis. In addition, considering that Sestrins are ROS-inducible and perform ROS-detoxifying as well as other metabolism-controlling functions, they are potential regulators of mitohormesis. This is a concept in which overall beneficial effects result from low-level oxidative stress stimuli, such as the ones induced by caloric restriction or physical exercise. In this perspective, we incorporate our recent insight obtained from the Sestrin2 study towards a better understanding of the relationship between ROS, Sestrin2 and mitochondrial metabolism in the context of brown adipocyte physiology.

  1. NAMPT-Mediated NAD(+) Biosynthesis in Adipocytes Regulates Adipose Tissue Function and Multi-organ Insulin Sensitivity in Mice.

    Science.gov (United States)

    Stromsdorfer, Kelly L; Yamaguchi, Shintaro; Yoon, Myeong Jin; Moseley, Anna C; Franczyk, Michael P; Kelly, Shannon C; Qi, Nathan; Imai, Shin-Ichiro; Yoshino, Jun

    2016-08-16

    Obesity is associated with adipose tissue dysfunction and multi-organ insulin resistance. However, the mechanisms of such obesity-associated systemic metabolic complications are not clear. Here, we characterized mice with adipocyte-specific deletion of nicotinamide phosphoribosyltransferase (NAMPT), a rate-limiting NAD(+) biosynthetic enzyme known to decrease in adipose tissue of obese and aged rodents and people. We found that adipocyte-specific Nampt knockout mice had severe insulin resistance in adipose tissue, liver, and skeletal muscle and adipose tissue dysfunction, manifested by increased plasma free fatty acid concentrations and decreased plasma concentrations of a major insulin-sensitizing adipokine, adiponectin. Loss of Nampt increased phosphorylation of CDK5 and PPARγ (serine-273) and decreased gene expression of obesity-linked phosphorylated PPARγ targets in adipose tissue. These deleterious alterations were normalized by administering rosiglitazone or a key NAD(+) intermediate, nicotinamide mononucleotide (NMN). Collectively, our results provide important mechanistic and therapeutic insights into obesity-associated systemic metabolic derangements, particularly multi-organ insulin resistance. PMID:27498863

  2. NAMPT-mediated NAD+ biosynthesis in adipocytes regulates adipose tissue function and multi-organ insulin sensitivity in mice

    Science.gov (United States)

    Stromsdorfer, Kelly L.; Yamaguchi, Shintaro; Yoon, Myeong Jin; Moseley, Anna C.; Franczyk, Michael P.; Kelly, Shannon C.; Qi, Nathan; Imai, Shin-ichiro; Yoshino, Jun

    2016-01-01

    SUMMARY Obesity is associated with adipose tissue dysfunction and multi-organ insulin resistance. However, the mechanisms of such obesity-associated systemic metabolic complications are not clear. Here, we characterized mice with adipocyte-specific deletion of nicotinamide phosphoribosyltransferase (NAMPT), a rate-limiting NAD+ biosynthetic enzyme known to decrease in adipose tissue of obese and aged rodents and people. We found that adipocyte-specific Nampt knockout mice had severe insulin resistance in adipose tissue, liver, and skeletal muscle, and adipose tissue dysfunction, manifested by increased plasma free fatty acids concentrations and decreased plasma concentrations of a major insulin-sensitizing adipokine, adiponectin. Loss of Nampt increased phosphorylation of CDK5 and PPARγ (serine-273) and decreased gene expression of obesity-linked phosphorylated PPARγ targets in adipose tissue. Remarkably, these deleterious alterations were normalized by administering rosiglitazone or a key NAD+ intermediate, nicotinamide mononucleotide (NMN). Collectively, our results provide important mechanistic and therapeutic insights into obesity-associated systemic metabolic derangements, particularly multi-organ insulin resistance. PMID:27498863

  3. Regulation of glucose utilization and lipogenesis in adipose tissue of diabetic and fat fed animals: Effects of insulin and manganese

    Indian Academy of Sciences (India)

    Najma Z Baquer; M Sinclair; S Kunjara; Umesh C S Yadav; P McLean

    2003-03-01

    In order to evaluate the modulatory effects of manganese, high fat diet fed and alloxan diabetic rats were taken and the changes in the glucose oxidation, glycerol release and effects of manganese on these parameters were measured from adipose tissue. An insulin-mimetic effect of manganese was observed in the adipose tissue in the controls and an additive effect of insulin and manganese on glucose oxidation was seen when Mn2+ was added in vitro. The flux of glucose through the pentose phosphate pathway and glycolysis was significantly decreased in high fat fed animals. Although the in vitro addition of Mn2+ was additive with insulin when 14CO2 was measured from control animals, it was found neither in young diabetic animals (6–8 weeks old) nor in the old (16 weeks old). Both insulin and manganese caused an increased oxidation of carbon-1 of glucose and an increase of its incorporation into 14C-lipids in the young control animals; the additive effect of insulin and manganese suggests separate site of action. This effect was decreased in fat fed animals, diabetic animals and old animals. Manganese alone was found to decrease glycerol in both the control and diabetic adipose tissue in in vitro incubations. The results of the effects of glucose oxidation, lipogenesis, and glycerol release in adipose tissue of control and diabetic animals of different ages are presented together with the effect of manganese on adipose tissue from high fat milk diet fed animals.

  4. The protein factor-arrest 11 (Far11) is essential for the toxicity of human caspase-10 in yeast and participates in the regulation of autophagy and the DNA damage signaling.

    Science.gov (United States)

    Lisa-Santamaría, Patricia; Jiménez, Alberto; Revuelta, José L

    2012-08-24

    The heterologous expression of human caspase-10 in Saccharomyces cerevisiae induces a lethal phenotype, which includes some hallmarks of apoptosis and autophagy, alterations in the intra-S checkpoint, and cell death. To determine the cellular processes and pathways that are responsible of the caspase-10-induced cell death we have designed a loss-of-function screening system to identify genes that are essential for the lethal phenotype. We observed that the ER-Golgi-localized family of proteins Far, MAPK signaling, the autophagy machinery, and several kinases and phosphatases are essential for caspase-10 toxicity. We also found that the expression of caspase-10 elicits a simultaneous activation of the MAP kinases Fus3, Kss1, and Slt2. Furthermore, the protein Far11, which is a target of MAP kinases, is essential for the dephosphorylation of Atg13 and, consequently, for the induction of autophagy. In addition, Far11 participates in the regulation of the DNA damage response through the dephosphorylation of Rad53. Finally, we have also demonstrated that Far11 is able to physically interact with the phosphatases Pph21, Pph22, and Pph3. Overall, our results indicate that the expression of human caspase-10 in S. cerevisiae activates an intracellular death signal that depends on the Far protein complex and that Far11 may function as a regulator subunit of phosphatases in different processes, thus representing a mechanistic link between them. PMID:22782902

  5. Annexin A2 Regulates Autophagy in Pseudomonas aeruginosa Infection through the Akt1-mTOR-ULK1/2 Signaling Pathway.

    Science.gov (United States)

    Li, Rongpeng; Tan, Shirui; Yu, Min; Jundt, Michael C; Zhang, Shuang; Wu, Min

    2015-10-15

    Earlier studies reported that a cell membrane protein, Annexin A2 (AnxA2), plays multiple roles in the development, invasion, and metastasis of cancer. Recent studies demonstrated that AnxA2 also functions in immunity against infection, but the underlying mechanism remains largely elusive. Using a mouse infection model, we reveal a crucial role for AnxA2 in host defense against Pseudomonas aeruginosa, as anxa2(-/-) mice manifested severe lung injury, systemic dissemination, and increased mortality compared with wild-type littermates. In addition, anxa2(-/-) mice exhibited elevated inflammatory cytokines (TNF-α, IL-6, IL-1β, and IFN-γ), decreased bacterial clearance by macrophages, and increased superoxide release in the lung. We further identified an unexpected molecular interaction between AnxA2 and Fam13A, which activated Rho GTPase. P. aeruginosa infection induced autophagosome formation by inhibiting Akt1 and mTOR. Our results indicate that AnxA2 regulates autophagy, thereby contributing to host immunity against bacteria through the Akt1-mTOR-ULK1/2 signaling pathway.

  6. A nonapoptotic role for CASP2/caspase 2: modulation of autophagy.

    Science.gov (United States)

    Tiwari, Meenakshi; Sharma, Lokendra K; Vanegas, Difernando; Callaway, Danielle A; Bai, Yidong; Lechleiter, James D; Herman, Brian

    2014-06-01

    CASP2/caspase 2 plays a role in aging, neurodegeneration, and cancer. The contributions of CASP2 have been attributed to its regulatory role in apoptotic and nonapoptotic processes including the cell cycle, DNA repair, lipid biosynthesis, and regulation of oxidant levels in the cells. Previously, our lab demonstrated CASP2-mediated modulation of autophagy during oxidative stress. Here we report the novel finding that CASP2 is an endogenous repressor of autophagy. Knockout or knockdown of CASP2 resulted in upregulation of autophagy in a variety of cell types and tissues. Reinsertion of Caspase-2 gene (Casp2) in mouse embryonic fibroblast (MEFs) lacking Casp2 (casp2(-/-)) suppresses autophagy, suggesting its role as a negative regulator of autophagy. Loss of CASP2-mediated autophagy involved AMP-activated protein kinase, mechanistic target of rapamycin, mitogen-activated protein kinase, and autophagy-related proteins, indicating the involvement of the canonical pathway of autophagy. The present study also demonstrates an important role for loss of CASP2-induced enhanced reactive oxygen species production as an upstream event in autophagy induction. Additionally, in response to a variety of stressors that induce CASP2-mediated apoptosis, casp2(-/-) cells demonstrate a further upregulation of autophagy compared with wild-type MEFs, and upregulated autophagy provides a survival advantage. In conclusion, we document a novel role for CASP2 as a negative regulator of autophagy, which may provide important insight into the role of CASP2 in various processes including aging, neurodegeneration, and cancer.

  7. Autophagy and its neuroprotection in neurodegenerative diseases

    Institute of Scientific and Technical Information of China (English)

    Ping Gu; Avaneesh Jakkoju; Mingwei Wang; Weidong Le

    2011-01-01

    It has been suggested that protein misfolding and aggregation contribute significantly to the development of neurodegenerative diseases. Misfolded and aggregated proteins are cleared by ubiquitin proteasomal system (UPS) and by both Micro and Macro autophagy lysosomal pathway (ALP). Autophagosomal dysfunction has been implicated in an increasing number of diseases including neurodegenerative diseases. Autophagy is a cellular self-eating process that plays an important role in neuroprotection as well as neuronal injury and death. While a decrease in autophagic activity interferes with protein degradation and possibly organelle turnover, increased autophagy has been shown to facilitate the clearance of aggregation-prone proteins and promote neuronal survival in a number of disease models. On the other hand, too much autophagic activity can be detrimental, suggesting the regulation of autophagy is critical in dictating cell fate. In this review paper, we will discuss various aspects of ALP biology and its dual functions in neuronal cell death and survival. We will also evaluate the role of autophagy in neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis. Finally, we will explore the therapeutic potential of autophagy modifiers in several neurodegenerative diseases.

  8. Visceral adiposity syndrome.

    Science.gov (United States)

    Lopes, Heno F; Corrêa-Giannella, Maria Lúcia; Consolim-Colombo, Fernanda M; Egan, Brent M

    2016-01-01

    adipose tissue blocks lipolysis to a variety of lipolytic stimuli and adipose tissue send inputs to the brain. An imbalance of sympathetic/parasympathetic and alpha2 adrenergic/beta3 receptor is related to visceral adipose tissue storage and insulin sensitivity. Thus, in addition to the well-known factors classically associated with VAS, abnormal autonomic activity also emerges as an important factor regulating white adipose tissue, which highlights complex role of adipose tissue in the VAS. PMID:27437032

  9. Autophagy attenuates diabetic glomerular damage through protection of hyperglycemia-induced podocyte injury.

    Directory of Open Access Journals (Sweden)

    Li Fang

    Full Text Available Despite the recent attention focused on the important role of autophagy in maintaining podocyte homeostasis, little is known about the changes and mechanisms of autophagy in podocyte dysfunction under diabetic condition. In this study, we investigated the role of autophagy in podocyte biology and its involvement in the pathogenesis of diabetic nephropathy. Podocytes had a high basal level of autophagy. And basal autophagy inhibition either by 3-methyladenenine (3-MA or by Beclin-1 siRNA was detrimental to its architectural structure. However, under diabetic condition in vivo and under high glucose conditions in vitro, high basal level of autophagy in podocytes became defective and defective autophagy facilitated the podocyte injury. Since the dynamics of endoplasmic reticulum(ER seemed to play a vital role in regulating the autophagic flux, the results that Salubrinal/Tauroursodeoxycholic acid (TUDCA could restore defective autophagy further indicated that the evolution of autophagy may be mediated by the changes of cytoprotective output in the ER stress. Finally, we demonstrated in vivo that the autophagy of podocyte was inhibited under diabetic status and TUDCA could improve defective autophagy. Taken together, these data suggested that autophagy might be interrupted due to the failure of ER cytoprotective capacity upon high glucose induced unmitigated stress, and the defective autophagy might accelerate the irreparable progression of diabetic nephropathy.

  10. The HIF-2α-MALAT1-miR-216b axis regulates multi-drug resistance of hepatocellular carcinoma cells via modulating autophagy.

    Science.gov (United States)

    Yuan, Peng; Cao, Weibin; Zang, Quanling; Li, Guixin; Guo, Xiangfei; Fan, Jianghe

    2016-09-23

    In this study, we firstly investigated the association among lncRNA MALAT1, HIF-1α and HIF-2α in hepatocellular carcinoma (HCC) cells. Then, we investigated the regulative effect of MALAT1 on multi-drug resistance (MDR) in HCC cells and the underlying mechanism. The results showed that MALAT1 was over two times higher in BEL-7402/5-FU cells than in BEL-7402 cells. It was HIF-2α, but not HIF-1α induced MALAT1 upregulation in HCC cells. Dual luciferase assay demonstrated that there were at least two binding sites of miR-26b in MALAT1. Therefore, we infer that there is a HIF-2α-MALAT1-miR-216b axis in HCC cells. Cell viability assay showed that both MALAT1 siRNA and miR-216b mimics reduced IC50 of 5-FU, ADR and MMC in BEL-7402/5-FU cells. MALAT1 siRNA and miR-216b mimics showed similar effect as 3-MA on reducing LC3-II levels, inhibiting p62 degradation and suppressing GFP-LC3 puncta formation in BEL-7402/5-FU cells. Flow cytometric analysis showed that 3-MA treatment, MALAT1 siRNA and miR-216b mimics all promoted 5-FU induced apoptosis in BEL-7402/5-FU cells. Therefore, this study firstly revealed that there is a HIF-2α-MALAT1-miR-216b axis regulating MDR of HCC cells via modulating autophagy. PMID:27524242

  11. Serratia marcescens ShlA pore-forming toxin is responsible for early induction of autophagy in host cells and is transcriptionally regulated by RcsB.

    Science.gov (United States)

    Di Venanzio, Gisela; Stepanenko, Tatiana M; García Véscovi, Eleonora

    2014-09-01

    Serratia marcescens is a Gram-negative bacterium that thrives in a wide variety of ambient niches and interacts with an ample range of hosts. As an opportunistic human pathogen, it has increased its clinical incidence in recent years, being responsible for life-threatening nosocomial infections. S. marcescens produces numerous exoproteins with toxic effects, including the ShlA pore-forming toxin, which has been catalogued as its most potent cytotoxin. However, the regulatory mechanisms that govern ShlA expression, as well as its action toward the host, have remained unclear. We have shown that S. marcescens elicits an autophagic response in host nonphagocytic cells. In this work, we determine that the expression of ShlA is responsible for the autophagic response that is promoted prior to bacterial internalization in epithelial cells. We show that a strain unable to express ShlA is no longer able to induce this autophagic mechanism, while heterologous expression of ShlA/ShlB suffices to confer on noninvasive Escherichia coli the capacity to trigger autophagy. We also demonstrate that shlBA harbors a binding motif for the RcsB regulator in its promoter region. RcsB-dependent control of shlBA constitutes a feed-forward regulatory mechanism that allows interplay with flagellar-biogenesis regulation. At the top of the circuit, activated RcsB downregulates expression of flagella by binding to the flhDC promoter region, preventing FliA-activated transcription of shlBA. Simultaneously, RcsB interaction within the shlBA promoter represses ShlA expression. This circuit offers multiple access points to fine-tune ShlA production. These findings also strengthen the case for an RcsB role in orchestrating the expression of Serratia virulence factors.

  12. Set points, settling points and some alternative models: theoretical options to understand how genes and environments combine to regulate body adiposity

    Directory of Open Access Journals (Sweden)

    John R. Speakman

    2011-11-01

    Full Text Available The close correspondence between energy intake and expenditure over prolonged time periods, coupled with an apparent protection of the level of body adiposity in the face of perturbations of energy balance, has led to the idea that body fatness is regulated via mechanisms that control intake and energy expenditure. Two models have dominated the discussion of how this regulation might take place. The set point model is rooted in physiology, genetics and molecular biology, and suggests that there is an active feedback mechanism linking adipose tissue (stored energy to intake and expenditure via a set point, presumably encoded in the brain. This model is consistent with many of the biological aspects of energy balance, but struggles to explain the many significant environmental and social influences on obesity, food intake and physical activity. More importantly, the set point model does not effectively explain the ‘obesity epidemic’ – the large increase in body weight and adiposity of a large proportion of individuals in many countries since the 1980s. An alternative model, called the settling point model, is based on the idea that there is passive feedback between the size of the body stores and aspects of expenditure. This model accommodates many of the social and environmental characteristics of energy balance, but struggles to explain some of the biological and genetic aspects. The shortcomings of these two models reflect their failure to address the gene-by-environment interactions that dominate the regulation of body weight. We discuss two additional models – the general intake model and the dual intervention point model – that address this issue and might offer better ways to understand how body fatness is controlled.

  13. Emerging role of selective autophagy in human diseases.

    Directory of Open Access Journals (Sweden)

    Kenji eMizumura

    2014-11-01

    Full Text Available AbstractAutophagy was originally described as a highly conserved system for the degradation of cytosol through a lysosome-dependent pathway. In response to starvation, autophagy degrades organelles and proteins to provide metabolites and energy for its pro-survival effects. Autophagy is recognized as playing a role in the pathogenesis of disease either directly or indirectly, through the regulation of vital processes such as programmed cell death, inflammation, and adaptive immune mechanisms. Recent studies have demonstrated that autophagy is not only a simple metabolite recycling system, but also has the ability to degrade specific cellular targets, such as mitochondria, cilia, and invading bacteria. In addition, selective autophagy has also been implicated in vesicle trafficking pathways, with potential roles in secretion and other intracellular transport processes. Selective autophagy has drawn the attention of researchers because of its potential importance in clinical diseases. Therapeutic strategies to target selective autophagy rather than general autophagy may maximize clinical benefit by enhancing selectivity. In this review, we outline the principle components of selective autophagy processes and their emerging importance in human disease, with an emphasis on pulmonary diseases.

  14. Exercise reduces adipose tissue via cannabinoid receptor type 1 which is regulated by peroxisome proliferator-activated receptor-delta

    DEFF Research Database (Denmark)

    Yan, Zhen Cheng; Liu, Dao Yan; Zhang, Li Li;

    2007-01-01

    Obesity is one major cardiovascular risk factor. We tested effects of endurance exercise on cannabinoid receptor type 1 (CB1) and peroxisome proliferator-activated receptor-delta (PPAR-delta)-dependent pathways in adipose tissue. Male Wistar rats were randomly assigned to standard laboratory chow...

  15. Genetic versus Non-Genetic Regulation of miR-103, miR-143 and miR-483-3p Expression in Adipose Tissue and Their Metabolic Implications-A Twin Study

    DEFF Research Database (Denmark)

    Bork-Jensen, Jette; Thuesen, Anne Cathrine Baun; Bang-Bertelsen, Claus Heiner;

    2014-01-01

    Murine models suggest that the microRNAs miR-103 and miR-143 may play central roles in the regulation of subcutaneous adipose tissue (SAT) and development of type 2 diabetes (T2D). The microRNA miR-483-3p may reduce adipose tissue expandability and cause ectopic lipid accumulation, insulin...... expression levels. In addition, the miR-103 levels were positively associated with 2 h plasma glucose levels and hemoglobin A1c independently of BMI. Heritability estimates for all three microRNAs were low. In conclusion, the expression levels of miR-103, miR-143 and miR-483-3p in adipose tissue...... are primarily influenced by non-genetic factors, and miR-103 may be involved in the development of adiposity and control of glucose metabolism in humans....

  16. The Parkinson's disease-associated genes ATP13A2 and SYT11 regulate autophagy via a common pathway

    Science.gov (United States)

    Bento, Carla F.; Ashkenazi, Avraham; Jimenez-Sanchez, Maria; Rubinsztein, David C.

    2016-01-01

    Forms of Parkinson's disease (PD) are associated with lysosomal and autophagic dysfunction. ATP13A2, which is mutated in some types of early-onset Parkinsonism, has been suggested as a regulator of the autophagy–lysosome pathway. However, little is known about the ATP13A2 effectors and how they regulate this pathway. Here we show that ATP13A2 depletion negatively regulates another PD-associated gene (SYT11) at both transcriptional and post-translational levels. Decreased SYT11 transcription is controlled by a mechanism dependent on MYCBP2-induced ubiquitination of TSC2, which leads to mTORC1 activation and decreased TFEB-mediated transcription of SYT11, while increased protein turnover is regulated by SYT11 ubiquitination and degradation. Both mechanisms account for a decrease in the levels of SYT11, which, in turn, induces lysosomal dysfunction and impaired degradation of autophagosomes. Thus, we propose that ATP13A2 and SYT11 form a new functional network in the regulation of the autophagy–lysosome pathway, which is likely to contribute to forms of PD-associated neurodegeneration. PMID:27278822

  17. Adipose tissues and thyroid hormones

    Directory of Open Access Journals (Sweden)

    Maria-Jesus eObregon

    2014-12-01

    Full Text Available The maintenance of energy balance is regulated by complex homeostatic mechanisms, including those emanating from adipose tissue. The main function of the adipose tissue is to store the excess of metabolic energy in the form of fat. The energy stored as fat can be mobilized during periods of energy deprivation (hunger, fasting, diseases. The adipose tissue has also a homeostatic role regulating energy balance and functioning as endocrine organ that secretes substances that control body homeostasis. Two adipose tissues have been identified: white and brown adipose tissues (WAT and BAT with different phenotype, function and regulation. WAT stores energy, while BAT dissipates energy as heat. Brown and white adipocytes have different ontogenetic origin and lineage and specific markers of WAT and BAT have been identified. Brite or beige adipose tissue has been identified in WAT with some properties of BAT. Thyroid hormones exert pleiotropic actions, regulating the differentiation process in many tissues including the adipose tissue. Adipogenesis gives raise to mature adipocytes and is regulated by several transcription factors (c/EBPs, PPARs that coordinately activate specific genes, resulting in the adipocyte phenotype. T3 regulates several genes involved in lipid mobilization and storage and in thermogenesis. Both WAT and BAT are targets of thyroid hormones, which regulate genes crucial for their proper function: lipogenesis, lipolysis, thermogenesis, mitochondrial function, transcription factors, the availability of nutrients. T3 acts directly through specific TREs in the gene promoters, regulating transcription factors. The deiodinases D3, D2 and D1 regulate the availability of T3. D3 is activated during proliferation, while D2 is linked to the adipocyte differentiation program, providing T3 needed for lipogenesis and thermogenesis. We examine the differences between BAT, WAT and brite/beige adipocytes and the process that activate UCP1 in WAT and

  18. Autophagy and cancer

    Institute of Scientific and Technical Information of China (English)

    Si-Zhao; Lu; Duygu; Dee; Harrison-Findik

    2013-01-01

    Autophagy is a homeostatic and evolutionarily conserved mechanism of self-digestion by which the cells degrade and recycle long-lived proteins and excess or damaged organelles.Autophagy is activated in response to both physiological and pathological stimuli including growth factor depletion,energy deficiency or the upregulation of Bcl-2 protein expression.A novel role of autophagy in various cancers has been proposed.Interestingly,evidence that supports both a positive and negative role of autophagy in the pathogenesis of cancer has been reported.As a tumor suppression mechanism,autophagy maintains genome stability,induces senescence and possibly autophagic cell death.On the other hand,autophagy participates in tumor growth and maintenance by supplying metabolic substrate,limiting oxidative stress,and maintaining cancer stem cell population.It has been proposed that the differential roles of autophagy in cancer are disease type and stage specific.In addition,substrate selectivity might be involved in carrying out the specific effect of autophagy in cancer,and represents one of the potential directions for future studies.

  19. Selective inhibition of PI3K/Akt/mTOR signaling pathway regulates autophagy of macrophage and vulnerability of atherosclerotic plaque.

    Directory of Open Access Journals (Sweden)

    Chungang Zhai

    Full Text Available Macrophage infiltration contributes to the instability of atherosclerotic plaques. In the present study, we investigated whether selective inhibition of PI3K/Akt/mTOR signaling pathway can enhance the stability of atherosclerotic plaques by activation of macrophage autophagy. In vitro study, selective inhibitors or siRNA of PI3K/Akt/mTOR pathways were used to treat the rabbit's peritoneal primary macrophage cells. Inflammation related cytokines secreted by macrophages were measured. Ultrastructure changes of macrophages were examined by transmission electron microscope. mRNA or protein expression levels of autophagy related gene Beclin 1, protein 1 light chain 3 II dots (LC3-II or Atg5-Atg12 conjugation were assayed by quantitative RT-PCR or Western blot. In vivo study, vulnerable plaque models were established in 40 New Zealand White rabbits and then drugs or siRNA were given for 8 weeks to inhibit the PI3K/Akt/mTOR signaling pathway. Intravascular ultrasound (IVUS was performed to observe the plaque imaging. The ultrastructure of the abdominal aortic atherosclerosis lesions were analyzed with histopathology. RT-PCR or Western blot methods were used to measure the expression levels of corresponding autophagy related molecules. We found that macrophage autophagy was induced in the presence of Akt inhibitor, mTOR inhibitor and mTOR-siRNA in vitro study, while PI3K inhibitor had the opposite role. In vivo study, we found that macrophage autophagy increased significantly and the rabbits had lower plaque rupture incidence, lower plaque burden and decreased vulnerability index in the inhibitors or siRNA treated groups. We made a conclusion that selective inhibition of the Akt/mTOR signal pathway can reduce macrophages and stabilize the vulnerable atherosclerotic plaques by promoting macrophage autophagy.

  20. Chemical Inhibition of Autophagy

    DEFF Research Database (Denmark)

    Baek, Eric; Lin Kim, Che; Gyeom Kim, Mi;

    2016-01-01

    Chinese hamster ovary (CHO) cells activate and undergo apoptosis and autophagy for various environmental stresses. Unlike apoptosis, studies on increasing the production of therapeutic proteins in CHO cells by targeting the autophagy pathway are limited. In order to identify the effects of chemical...... autophagy inhibitors on the specific productivity (qp), nine chemical inhibitors that had been reported to target three different phases of autophagy (metformin, dorsomorphin, resveratrol, and SP600125 against initiation and nucleation; 3-MA, wortmannin, and LY294002 against elongation, and chloroquine...... significantly increased the qp of DG44-Fc and DUKX-Fc. In contrast, for DG44-Ab, only 3-MA significantly increased the qp. The autophagy-inhibiting activity of the nine chemical inhibitors on the rCHO cell lines was evaluated through Western blot analysis and flow cytometry. Unexpectedly, some chemical...

  1. Autophagy in Hepatic Fibrosis

    Directory of Open Access Journals (Sweden)

    Yang Song

    2014-01-01

    Full Text Available Hepatic fibrosis is a leading cause of morbidity and mortality worldwide. Hepatic fibrosis is usually associated with chronic liver diseases caused by infection, drugs, metabolic disorders, or autoimmune imbalances. Effective clinical therapies are still lacking. Autophagy is a cellular process that degrades damaged organelles or protein aggregation, which participates in many pathological processes including liver diseases. Autophagy participates in hepatic fibrosis by activating hepatic stellate cells and may participate as well through influencing other fibrogenic cells. Besides that, autophagy can induce some liver diseases to develop while it may play a protective role in hepatocellular abnormal aggregates related liver diseases and reduces fibrosis. With a better understanding of the potential effects of autophagy on hepatic fibrosis, targeting autophagy might be a novel therapeutic strategy for hepatic fibrosis in the near future.

  2. Crosstalk between Autophagy and Apoptosis: Potential and Emerging Therapeutic Targets for Cardiac Diseases

    Directory of Open Access Journals (Sweden)

    Meng Li

    2016-03-01

    Full Text Available Autophagy is a cell survival process which is related to breaking down and reusing cytoplasm components. Moreover, autophagy regulates cell death under certain conditions. Apoptosis has the characteristics of chromatin agglutination and the shrinking of nuclear and apoptosis body form. Even if the mechanisms of autophagy and apoptosis have differences, some proteins modulate both autophagy and apoptosis. Crosstalk between them exists. This review highlights recent advances in the interaction of autophagy and apoptosis and its importance in the development of cardiovascular diseases.

  3. Regulated expression of the obese gene product (leptin) in white adipose tissue and 3T3-L1 adipocytes.

    OpenAIRE

    MacDougald, O A; Hwang, C. S.; Fan, H; Lane, M D

    1995-01-01

    A mutation within the obese gene was recently identified as the genetic basis for obesity in the ob/ob mouse. The obese gene product, leptin, is a 16-kDa protein expressed predominantly in adipose tissue. Consistent with leptin's postulated role as an extracellular signaling protein, human embryonic kidney 293 cells transfected with the obese gene secreted leptin with minimal intracellular accumulation. Upon differentiation of 3T3-L1 preadipocytes into adipocytes, the leptin mRNA was expresse...

  4. Tartrate resistant acid phosphatase 5a : a potential regulator of adipocyte cell number and differentiation in white adipose tissue

    OpenAIRE

    Patlaka, Christina

    2015-01-01

    Tartrate- resistant acid phosphatase (TRAP) exists in two isoforms, TRAP 5a which is monomeric and TRAP 5b which is a dimer generated by proteolytic cleavage of TRAP 5a, that exhibit different functions and localizations. TRAP 5a is expressed by adipose tissue macrophages and secreted into the extracellular environment and has been shown to lead to hyperplastic insulin- sensitive obesity when over-expressed in mice. In bone, TRAP is suggested to interact with the heparan sulfat...

  5. Sexual dimorphism in activation of placental autophagy in obese women with evidence for fetal programming from a placenta-specific mouse model.

    Science.gov (United States)

    Muralimanoharan, Sribalasubashini; Gao, Xiaoli; Weintraub, Susan; Myatt, Leslie; Maloyan, Alina

    2016-05-01

    The incidence of maternal obesity and its co-morbidities (diabetes, cardiovascular disease) continues to increase at an alarming rate, with major public health implications. In utero exposure to maternal obesity has been associated with development of cardiovascular and metabolic diseases in the offspring as a result of developmental programming. The placenta regulates maternal-fetal metabolism and shows significant changes in its function with maternal obesity. Autophagy is a cell-survival process, which is responsible for the degradation of damaged organelles and misfolded proteins. Here we show an activation of autophagosomal formation and autophagosome-lysosome fusion in placentas of males but not females from overweight (OW) and obese (OB) women vs. normal weight (NW) women. However, total autophagic activity in these placentas appeared to be decreased as it showed an increase in SQSTM1/p62 and a decrease in lysosomal biogenesis. A mouse model with a targeted deletion of the essential autophagy gene Atg7 in placental tissue showed significant placental abnormalities comparable to those seen in human placenta with maternal obesity. These included a decrease in expression of mitochondrial genes and antioxidants, and decreased lysosomal biogenesis. Strikingly, the knockout mice were developmentally programmed as they showed an increased sensitivity to high-fat diet-induced obesity, hyperglycemia, hyperinsulinemia, increased adiposity, and cardiac remodeling. In summary, our results indicate a sexual dimorphism in placental autophagy in response to maternal obesity. We also show that autophagy plays an important role in placental function and that inhibition of placental autophagy programs the offspring to obesity, and to metabolic and cardiovascular diseases. PMID:26986453

  6. The protective roles of autophagy in ischemic preconditioning

    Institute of Scientific and Technical Information of China (English)

    Wen-jun YAN; Hai-long DONG; Li-ze XIONG

    2013-01-01

    Autophagy,a process for the degradation of protein aggregates and dysfunctional organelles,is required for cellular homeostasis and cell survival in response to stress and is implicated in endogenous protection.Ischemic preconditioning is a brief and nonlethal episode of ischemia,confers protection against subsequent ischemia-repenfusion through the up-regulation of endogenous protective mechanisms.Emerging evidence shows that autophagy is associated with the protective effect of ischemic preconditioning.This review summarizes recent progress in research on the functions and regulations of the autophagy pathway in preconditioning-induced protection and cellular survival.

  7. Telemetric control of peripheral lipophagy by hypothalamic autophagy.

    Science.gov (United States)

    Martinez-Lopez, Nuria; Singh, Rajat

    2016-08-01

    Autophagy maintains cellular quality control by degrading organelles, and cytosolic proteins and their aggregates in lysosomes. Autophagy also degrades lipid droplets (LD) through a process termed lipophagy. During lipophagy, LD are sequestered within autophagosomes and degraded by lysosomal acid lipases to generate free fatty acids that are β-oxidized for energy. Lipophagy was discovered in hepatocytes, and since then has been shown to function in diverse cell types. Whether lipophagy degrades LD in the major fat storing cell-the adipocyte-remained unclear. We have found that blocking autophagy in brown adipose tissues (BAT) by deleting the autophagy gene Atg7 in BAT MYF5 (myogenic factor 5)-positive progenitors increases basal lipid content in BAT and decreases lipid utilization during cold exposure-indicating that lipophagy contributes to lipohomeostasis in the adipose tissue. Surprisingly, knocking out Atg7 in hypothalamic proopiomelanocortin (POMC) neurons also blocks lipophagy in BAT and liver suggesting that specific neurons within the central nervous system (CNS) exert telemetric control over lipophagy in BAT and liver. PMID:27341145

  8. Autophagy in Plants--What's New on the Menu?

    Science.gov (United States)

    Michaeli, Simon; Galili, Gad; Genschik, Pascal; Fernie, Alisdair R; Avin-Wittenberg, Tamar

    2016-02-01

    Autophagy is a major cellular degradation pathway in eukaryotes. Recent studies have revealed the importance of autophagy in many aspects of plant life, including seedling establishment, plant development, stress resistance, metabolism, and reproduction. This is manifested by the dual ability of autophagy to execute bulk degradation under severe environmental conditions, while simultaneously to be highly selective in targeting specific compartments and protein complexes to regulate key cellular processes, even during favorable growth conditions. Delivery of cellular components to the vacuole enables their recycling, affecting the plant metabolome, especially under stress. Recent research in Arabidopsis has further unveiled fundamental mechanistic aspects in autophagy which may have relevance in non-plant systems. We review the most recent discoveries concerning autophagy in plants, touching upon all these aspects.

  9. Targeting autophagy to sensitive glioma to temozolomide treatment.

    Science.gov (United States)

    Yan, Yuanliang; Xu, Zhijie; Dai, Shuang; Qian, Long; Sun, Lunquan; Gong, Zhicheng

    2016-02-02

    Temozolomide (TMZ), an alkylating agent, is widely used for treating primary and recurrent high-grade gliomas. However, the efficacy of TMZ is often limited by the development of resistance. Recently, studies have found that TMZ treatment could induce autophagy, which contributes to therapy resistance in glioma. To enhance the benefit of TMZ in the treatment of glioblastomas, effective combination strategies are needed to sensitize glioblastoma cells to TMZ. In this regard, as autophagy could promote cell survival or autophagic cell death, modulating autophagy using a pharmacological inhibitor, such as chloroquine, or an inducer, such as rapamycin, has received considerably more attention. To understand the effectiveness of regulating autophagy in glioblastoma treatment, this review summarizes reports on glioblastoma treatments with TMZ and autophagic modulators from in vitro and in vivo studies, as well as clinical trials. Additionally, we discuss the possibility of using autophagy regulatory compounds that can sensitive TMZ treatment as a chemotherapy for glioma treatment.

  10. Autophagy process is associated with anti-neoplastic function

    Institute of Scientific and Technical Information of China (English)

    Chong Wang; Yachen Wang; Michael A. McNutt; Wei-Guo Zhu

    2011-01-01

    Autophagy is a highly conserved process of cellular degradation, which is present in yeast, plants, and mammals.Under normal physiological conditions, autophagy acts to maintain cellular homeostasis and regulate the turnover of organelles.In response to cellular stresses, autophagy prevents the accumulation of impaired proteins and organelles, which serves to inhibit carcinogenesis.On this basis,it is widely accepted that most tumor suppressors, such as beclin 1 associated proteins, forkhead box class O (FoxO)family proteins, multiple mammalian target of Rapamycin (mTOR) inactivators, and nuclear p53 play a role in indu cing autophagy.Here, we focus on how the process of autophagy is associated with anti-neoplastic function.

  11. Characterization of early autophagy signaling by quantitative phosphoproteomics

    DEFF Research Database (Denmark)

    Rigbolt, Kristoffer Tg; Zarei, Mostafa; Sprenger, Adrian;

    2014-01-01

    Under conditions of nutrient shortage autophagy is the primary cellular mechanism ensuring availability of substrates for continuous biosynthesis. Subjecting cells to starvation or rapamycin efficiently induces autophagy by inhibiting the MTOR signaling pathway triggering increased autophagic flux....... To elucidate the regulation of early signaling events upon autophagy induction, we applied quantitative phosphoproteomics characterizing the temporal phosphorylation dynamics after starvation and rapamycin treatment. We obtained a comprehensive atlas of phosphorylation kinetics within the first 30 min upon...... induction of autophagy with both treatments affecting widely different cellular processes. The identification of dynamic phosphorylation already after 2 min demonstrates that the earliest events in autophagy signaling occur rapidly after induction. The data was subjected to extensive bioinformatics analysis...

  12. Host Cell Autophagy in Immune Response to Zoonotic Infections

    Directory of Open Access Journals (Sweden)

    Panagiotis Skendros

    2012-01-01

    Full Text Available Autophagy is a fundamental homeostatic process in which cytoplasmic targets are sequestered within double-membraned autophagosomes and subsequently delivered to lysosomes for degradation. Accumulating evidence supports the pivotal role of autophagy in host defense against intracellular pathogens implicating both innate and adaptive immunity. Many of these pathogens cause common zoonotic infections worldwide. The induction of the autophagic machinery by innate immune receptors signaling, such as TLRs, NOD1/2, and p62/SQSTM1 in antigen-presenting cells results in inhibition of survival and elimination of invading pathogens. Furthermore, Th1 cytokines induce the autophagic process, whereas autophagy also contributes to antigen processing and MHC class II presentation, linking innate to adaptive immunity. However, several pathogens have developed strategies to avoid autophagy or exploit autophagic machinery to their advantage. This paper focuses on the role of host cell autophagy in the regulation of immune response against intracellular pathogens, emphasizing on selected bacterial and protozoan zoonoses.

  13. Autophagy in Plants--What's New on the Menu?

    Science.gov (United States)

    Michaeli, Simon; Galili, Gad; Genschik, Pascal; Fernie, Alisdair R; Avin-Wittenberg, Tamar

    2016-02-01

    Autophagy is a major cellular degradation pathway in eukaryotes. Recent studies have revealed the importance of autophagy in many aspects of plant life, including seedling establishment, plant development, stress resistance, metabolism, and reproduction. This is manifested by the dual ability of autophagy to execute bulk degradation under severe environmental conditions, while simultaneously to be highly selective in targeting specific compartments and protein complexes to regulate key cellular processes, even during favorable growth conditions. Delivery of cellular components to the vacuole enables their recycling, affecting the plant metabolome, especially under stress. Recent research in Arabidopsis has further unveiled fundamental mechanistic aspects in autophagy which may have relevance in non-plant systems. We review the most recent discoveries concerning autophagy in plants, touching upon all these aspects. PMID:26598298

  14. Adipose tissue plasticity from WAT to BAT and in between.

    Science.gov (United States)

    Lee, Yun-Hee; Mottillo, Emilio P; Granneman, James G

    2014-03-01

    Adipose tissue plays an essential role in regulating energy balance through its metabolic, cellular and endocrine functions. Adipose tissue has been historically classified into anabolic white adipose tissue and catabolic brown adipose tissue. An explosion of new data, however, points to the remarkable heterogeneity among the cells types that can become adipocytes, as well as the inherent metabolic plasticity of mature cells. These data indicate that targeting cellular and metabolic plasticity of adipose tissue might provide new avenues for treatment of obesity-related diseases. This review will discuss the developmental origins of adipose tissue, the cellular complexity of adipose tissues, and the identification of progenitors that contribute to adipogenesis throughout development. We will touch upon the pathological remodeling of adipose tissue and discuss how our understanding of adipose tissue remodeling can uncover new therapeutic targets. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease.

  15. Rab32 is important for autophagy and lipid storage in Drosophila.

    Directory of Open Access Journals (Sweden)

    Chao Wang

    Full Text Available Lipids are essential components of all organisms. Within cells, lipids are mainly stored in a specific type of organelle, called the lipid droplet. The molecular mechanisms governing the dynamics of lipid droplets have been little explored. The protein composition of lipid droplets has been analyzed in numerous proteomic studies, and a large number of lipid droplet-associated proteins have been identified, including Rab small GTPases. Rab proteins are known to participate in many intracellular membranous events; however, their exact role in lipid droplets is largely unexplored. Here we systematically investigate the roles of Drosophila Rab family proteins in lipid storage in the larval adipose tissue, fat body. Rab32 and several other Rabs were found to affect the size of lipid droplets as well as lipid levels. Further studies showed that Rab32 and Rab32 GEF/Claret may be involved in autophagy, consequently affecting lipid storage. Loss-of-function mutants of several components in the autophagy pathway result in similar effects on lipid storage. These results highlight the potential functions of Rabs in regulating lipid metabolism.

  16. Autophagy in Skeletal Muscle Homeostasis and in Muscular Dystrophies

    OpenAIRE

    Paolo Bonaldo; Paolo Grumati

    2012-01-01

    Skeletal muscles are the agent of motion and one of the most important tissues responsible for the control of metabolism. The maintenance of muscle homeostasis is finely regulated by the balance between catabolic and anabolic process. Macroautophagy (or autophagy) is a catabolic process that provides the degradation of protein aggregation and damaged organelles through the fusion between autophagosomes and lysosomes. Proper regulation of the autophagy flux is fundamental for the homeostasis o...

  17. Autophagy in ageing and ageing-associated diseases

    Institute of Scientific and Technical Information of China (English)

    Li-qiang HE; Jia-hong LU; Zhen-yu YUE

    2013-01-01

    Autophagy is a cell self-digestion process via lysosomes that clears "cellular waste",including aberrantly modified proteins or protein aggregates and damaged organelles.Therefore,autophagy is considered a protein and organelle quality control mechanism that maintains normal cellular homeostasis.Dysfunctional autophagy has been observed in ageing tissues and several ageing-associated diseases.Lifespan of model organisms such as yeast,worms,flies,and mice can be extended through promoting autophagy,either by genetic manipulations such as over-expression of Sirtuin 1,or by administrations of rapamycin,resveratrol or spermidine.The evidence supports that autophagy may play an important role in delaying ageing or extending lifespan.In this review,we summarize the current knowledge about autophagy and its regulation,outline recent developments ie the genetic and pharmacological manipulations of autophagy that affects the lifespan,and discuss the role of autophagy in the ageing-related diseases.ow in Center for Neurodegenerative and Neuroimmunologic Diseases,Department of Neurology,University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School,Piscataway,NJ 08854,USA

  18. Cellular and Molecular Connections between Autophagy and Inflammation

    Directory of Open Access Journals (Sweden)

    Pierre Lapaquette

    2015-01-01

    Full Text Available Autophagy is an intracellular catabolic pathway essential for the recycling of proteins and larger substrates such as aggregates, apoptotic corpses, or long-lived and superfluous organelles whose accumulation could be toxic for cells. Because of its unique feature to engulf part of cytoplasm in double-membrane cup-shaped structures, which further fuses with lysosomes, autophagy is also involved in the elimination of host cell invaders and takes an active part of the innate and adaptive immune response. Its pivotal role in maintenance of the inflammatory balance makes dysfunctions of the autophagy process having important pathological consequences. Indeed, defects in autophagy are associated with a wide range of human diseases including metabolic disorders (diabetes and obesity, inflammatory bowel disease (IBD, and cancer. In this review, we will focus on interrelations that exist between inflammation and autophagy. We will discuss in particular how mediators of inflammation can regulate autophagy activity and, conversely, how autophagy shapes the inflammatory response. Impact of genetic polymorphisms in autophagy-related gene on inflammatory bowel disease will be also discussed.

  19. LC3B is indispensable for selective autophagy of p62 but not basal autophagy

    Energy Technology Data Exchange (ETDEWEB)

    Maruyama, Yoko [Protein Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506 (Japan); Department of Pediatrics, School of Medicine, Keio University, Tokyo 160-8582 (Japan); Sou, Yu-Shin; Kageyama, Shun [Protein Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506 (Japan); Takahashi, Takao [Department of Pediatrics, School of Medicine, Keio University, Tokyo 160-8582 (Japan); Ueno, Takashi [Division of Proteomics and Biomolecular Science, Center for Biomedical Research Resources, Juntendo University Graduate School of Medicine, Tokyo 113-8421 (Japan); Tanaka, Keiji [Laboratory of Protein Metabolism, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506 (Japan); Komatsu, Masaaki, E-mail: komatsu-ms@igakuken.or.jp [Protein Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506 (Japan); Department of Biochemistry, School of Medicine, Niigata University, Niigata 951-8510 (Japan); Ichimura, Yoshinobu, E-mail: ichimura-ys@igakuken.or.jp [Protein Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506 (Japan)

    2014-03-28

    Highlights: • Knockdown of LC3 or GABARAP families did not affect the basal autophagy. • LC3B has a higher affinity for the autophagy-specific substrate, p62, than GABARAPs. • siRNA-mediated knockdown of LC3B, but not that of GABARAPs, resulted in significant accumulation of p62. - Abstract: Autophagy is a unique intracellular protein degradation system accompanied by autophagosome formation. Besides its important role through bulk degradation in supplying nutrients, this system has an ability to degrade certain proteins, organelles, and invading bacteria selectively to maintain cellular homeostasis. In yeasts, Atg8p plays key roles in both autophagosome formation and selective autophagy based on its membrane fusion property and interaction with autophagy adaptors/specific substrates. In contrast to the single Atg8p in yeast, mammals have 6 homologs of Atg8p comprising LC3 and GABARAP families. However, it is not clear these two families have different or similar functions. The aim of this study was to determine the separate roles of LC3 and GABARAP families in basal/constitutive and/or selective autophagy. While the combined knockdown of LC3 and GABARAP families caused a defect in long-lived protein degradation through lysosomes, knockdown of each had no effect on the degradation. Meanwhile, knockdown of LC3B but not GABARAPs resulted in significant accumulation of p62/Sqstm1, one of the selective substrate for autophagy. Our results suggest that while mammalian Atg8 homologs are functionally redundant with regard to autophagosome formation, selective autophagy is regulated by specific Atg8 homologs.

  20. Autophagy in the light of sphingolipid metabolism

    DEFF Research Database (Denmark)

    Harvald, Eva Bang; Olsen, Anne Sofie Braun; Færgeman, Nils J.

    2015-01-01

    , has over the past decade been recognized as an essential part of metabolism. Autophagy not only rids the cell of excessive or damaged organelles, misfolded proteins, and invading microorganisms, it also provides nutrients to maintain crucial cellular functions. Besides serving as essential structural......Maintenance of cellular homeostasis requires tight and coordinated control of numerous metabolic pathways, which are governed by interconnected networks of signaling pathways and energy-sensing regulators. Autophagy, a lysosomal degradation pathway by which the cell self-digests its own components...

  1. YY1-MIR372-SQSTM1 regulatory axis in autophagy.

    Science.gov (United States)

    Feng, Lifeng; Ma, Yanning; Sun, Jie; Shen, Qi; Liu, Leiming; Lu, Haiqi; Wang, Faliang; Yue, Yongfang; Li, Jiaqiu; Zhang, Shenjie; Lin, Xiaoying; Chu, Jue; Han, Weidong; Wang, Xian; Jin, Hongchuan

    2014-08-01

    Autophagy is a self-proteolytic process that degrades intracellular material to enable cellular survival under unfavorable conditions. However, how autophagy is activated in human carcinogenesis remains largely unknown. Herein we report an epigenetic regulation of autophagy in human cancer cells. YY1 (YY1 transcription factor) is a well-known epigenetic regulator and is upregulated in many cancers. We found that YY1 knockdown inhibited cell viability and autophagy flux through downregulating SQSTM1 (sequestosome 1). YY1 regulated SQSTM1 expression through the epigenetic modulation of the transcription of MIR372 (microRNA 372) which was found to target SQSTM1 directly. During nutrient starvation, YY1 was stimulated to promote SQSTM1 expression and subsequent autophagy activation by suppressing MIR372 expression. Similar to YY1 depletion, MIR372 overexpression blocked autophagy activation and inhibited in vivo tumor growth. SQSTM1 upregulation and competent autophagy flux thus contributed to the oncogenic function of YY1. YY1-promoted SQSTM1 upregulation might be a useful histological marker for cancer detection and a potential target for drug development.

  2. Autophagy and Autoimmunity CrossTalks

    Directory of Open Access Journals (Sweden)

    Abhisek eBhattacharya

    2013-04-01

    Full Text Available Autophagy, initially viewed as a conserved bulk-degradation mechanism, has emerged as a central player in a multitude of immune functions. Autophagy is important in host defense against intracellular and extracellular pathogens, metabolic syndromes, immune cell homeostasis, antigen processing and presentation and maintenance of tolerance. The observation that the above processes are implicated in triggering or exacerbating autoimmunity raises the possibility that the autophagy pathway is involved in mediating autoimmune processes, either directly or as a consequence of innate or adaptive functions mediated by the pathway. Genome-wide association studies have shown association between single nucleotide polymorphisms (SNPs in autophagy related gene 5 (Atg5, and Atg16l1 with susceptibility to systemic lupus erythematous (SLE and Crohn’s disease, respectively. Enhanced expression of Atg5 was also reported in blood of mice with experimental autoimmune encephalomyelitis (EAE, a mouse model of multiple sclerosis (MS, and in T cells isolated from blood or brain tissues from patients with active relapse of MS. This review explores the roles of autophagy pathway in the innate and adaptive immune systems on regulating or mediating the onset, progression or exacerbation of autoimmune processes.

  3. Tumor Protein (TP)-p53 Members as Regulators of Autophagy in Tumor Cells upon Marine Drug Exposure.

    Science.gov (United States)

    Ratovitski, Edward A

    2016-01-01

    Targeting autophagic pathways might play a critical role in designing novel chemotherapeutic approaches in the treatment of human cancers, and the prevention of tumor-derived chemoresistance. Marine compounds were found to decrease tumor cell growth in vitro and in vivo. Some of them were shown to induce autophagic flux in tumor cells. In this study, we observed that the selected marine life-derived compounds (Chromomycin A2, Psammaplin A, and Ilimaquinone) induce expression of several autophagic signaling intermediates in human squamous cell carcinoma, glioblastoma, and colorectal carcinoma cells in vitro through a transcriptional regulation by tumor protein (TP)-p53 family members. These conclusions were supported by specific qPCR expression analysis, luciferase reporter promoter assay, and chromatin immunoprecipitation of promoter sequences bound to the TP53 family proteins, and silencing of the TP53 members in tumor cells. PMID:27537898

  4. 脂肪细胞的功能调节与脂肪组织重构%Functional regulation of adipocytes and adipose tissue remodeling

    Institute of Scientific and Technical Information of China (English)

    马度芳; 李晓

    2016-01-01

    Adipocytes are classified into three types, including white, brown, and “beige/brite” adipocytes. There exist differences in origin of adipocytes, gene expressions, morphology, and functions among three kinds of adipocytes. Multiple factors such as physical and chemical factors, neurohormonal and immunological factors, transcriptional factors have been shown to regulate and control the browning process and lipolysis of white adipose tissue. Thus, they may become new targets for anti-obesity intervention. In the process of obesity, chronic inflammation reaction, adipose tissue remodeling and abnormal angiogenesis occurring in the adipose tissue cause pathological fat expansion and reduce lipid storage in adipocytes. Understanding adipocytes biology is important to decipher how the aberrant adipose tissue contributes to obesity and metabolic disorders, and provides guidance for treating obesity.%脂肪细胞分为白色脂肪细胞、棕色脂肪细胞和米色脂肪细胞,三者在细胞来源、基因表达、形态学及功能方面存在差异。机体理化因素、神经内分泌和免疫因素、转录因子等多种因素可调控白色脂肪“棕色化”和脂肪分解。这些因素可能是药物干预的新靶点。肥胖时脂肪组织慢性炎症、纤维化和血管异常可导致脂肪扩充障碍,降低脂肪细胞的储脂能力。了解脂肪组织的这些生物学特性可揭示异常的脂肪组织如何导致肥胖以及肥胖相关的代谢紊乱,而且对于肥胖的治疗具有指导性意义。

  5. MicroRNA regulation of stem cell differentiation and diseases of the bone and adipose tissue: Perspectives on miRNA biogenesis and cellular transcriptome.

    Science.gov (United States)

    Martin, E C; Qureshi, A T; Dasa, V; Freitas, M A; Gimble, J M; Davis, T A

    2016-05-01

    MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression through targeting and suppression of mRNAs. miRNAs have been under investigation for the past twenty years and there is a large breadth of information on miRNAs in diseases such as cancer and immunology. Only more recently have miRNAs shown promise as a mechanism for intervention with respect to diseases of the bone and adipose tissue. In mesenchymal stem cell (MSC) differentiation, alterations in miRNA expression patterns can differentially promote an osteogenic, adipogenic, or myogenic phenotype. This manuscript reviews the current literature with respect to miRNAs in the context of MSC function with a particular focus on novel avenues for the examination of miRNA associated with bone and adipose tissue biology and disease. Specifically we highlight the need for a greater depth of investigation on MSCs with respect to miRNA biogenesis, processing, strand selection, and heterogeneity. We discuss how these mechanisms facilitate both altered miRNA expression and function.

  6. A role for TOR complex 2 signaling in promoting autophagy.

    Science.gov (United States)

    Vlahakis, Ariadne; Powers, Ted

    2014-01-01

    The conserved target of rapamycin (TOR) kinase is a central regulator of cell growth in response to nutrient availability. TOR forms 2 structurally and functionally distinct complexes, TORC1 and TORC2, and negatively regulates autophagy via TORC1. Here we demonstrate TOR also operates independently through the TORC2 signaling pathway to promote autophagy upon amino acid limitation. Under these conditions, TORC2, through its downstream target kinase Ypk1, inhibits the Ca(2+)- and Cmd1/calmodulin-dependent phosphatase, calcineurin, to enable the activation of the amino acid-sensing EIF2S1/eIF2α kinase, Gcn2, and promote autophagy. Thus TORC2 signaling regulates autophagy in a pathway distinct from TORC1 to provide a tunable response to the cellular metabolic state.

  7. A critical role of autophagy in plant resistance to necrotrophic fungal pathogens.

    Science.gov (United States)

    Lai, Zhibing; Wang, Fei; Zheng, Zuyu; Fan, Baofang; Chen, Zhixiang

    2011-06-01

    Autophagy is a pathway for degradation of cytoplasmic components. In plants, autophagy plays an important role in nutrient recycling during nitrogen or carbon starvation, and in responses to abiotic stress. Autophagy also regulates age- and immunity-related programmed cell death, which is important in plant defense against biotrophic pathogens. Here we show that autophagy plays a critical role in plant resistance to necrotrophic pathogens. ATG18a, a critical autophagy protein in Arabidopsis, interacts with WRKY33, a transcription factor that is required for resistance to necrotrophic pathogens. Expression of autophagy genes and formation of autophagosomes are induced in Arabidopsis by the necrotrophic fungal pathogen Botrytis cinerea. Induction of ATG18a and autophagy by B. cinerea was compromised in the wrky33 mutant, which is highly susceptible to necrotrophic pathogens. Arabidopsis mutants defective in autophagy exhibit enhanced susceptibility to the necrotrophic fungal pathogens B. cinerea and Alternaria brassicicola based on increased pathogen growth in the mutants. The hypersusceptibility of the autophagy mutants was associated with reduced expression of the jasmonate-regulated PFD1.2 gene, accelerated development of senescence-like chlorotic symptoms, and increased protein degradation in infected plant tissues. These results strongly suggest that autophagy cooperates with jasmonate- and WRKY33-mediated signaling pathways in the regulation of plant defense responses to necrotrophic pathogens.

  8. Lkb1 controls brown adipose tissue growth and thermogenesis by regulating the intracellular localization of CRTC3

    Science.gov (United States)

    Shan, Tizhong; Xiong, Yan; Zhang, Pengpeng; Li, Zhiguo; Jiang, Qingyang; Bi, Pengpeng; Yue, Feng; Yang, Gongshe; Wang, Yizhen; Liu, Xiaoqi; Kuang, Shihuan

    2016-01-01

    Brown adipose tissue (BAT) dissipates energy through Ucp1-mediated uncoupled respiration and its activation may represent a therapeutic strategy to combat obesity. Here we show that Lkb1 controls BAT expansion and UCP1 expression in mice. We generate adipocyte-specific Lkb1 knockout mice and show that, compared with wild-type littermates, these mice exhibit elevated UCP1 expression in BAT and subcutaneous white adipose tissue, have increased BAT mass and higher energy expenditure. Consequently, KO mice have improved glucose tolerance and insulin sensitivity, and are more resistant to high-fat diet (HFD)-induced obesity. Deletion of Lkb1 results in a cytoplasm to nuclear translocation of CRTC3 in brown adipocytes, where it recruits C/EBPβ to enhance Ucp1 transcription. In parallel, the absence of Lkb1 also suppresses AMPK activity, leading to activation of the mTOR signalling pathway and subsequent BAT expansion. These data suggest that inhibition of Lkb1 or its downstream signalling in adipocytes could be a novel strategy to increase energy expenditure in the context of obesity, diabetes and other metabolic diseases. PMID:27461402

  9. Targeting autophagy in cancer management – strategies and developments

    Directory of Open Access Journals (Sweden)

    Ozpolat B

    2015-09-01

    Full Text Available Bulent Ozpolat,1 Doris M Benbrook2 1Department of Experimental Therapeutics, The University of Texas – Houston, MD Anderson Cancer Center, Houston, TX, 2Department of Obstetrics and Gynecology, University of Oklahoma HSC, Oklahoma City, OK, USA Abstract: Autophagy is a highly regulated catabolic process involving lysosomal degradation of intracellular components, damaged organelles, misfolded proteins, and toxic aggregates, reducing oxidative stress and protecting cells from damage. The process is also induced in response to various conditions, including nutrient deprivation, metabolic stress, hypoxia, anticancer therapeutics, and radiation therapy to adapt cellular conditions for survival. Autophagy can function as a tumor suppressor mechanism in normal cells and dysregulation of this process (ie, monoallelic Beclin-1 deletion may lead to malignant transformation and carcinogenesis. In tumors, autophagy is thought to promote tumor growth and progression by helping cells to adapt and survive in metabolically-challenged and harsh tumor microenvironments (ie, hypoxia and acidity. Recent in vitro and in vivo studies in preclinical models suggested that modulation of autophagy can be used as a therapeutic modality to enhance the efficacy of conventional therapies, including chemo and radiation therapy. Currently, more than 30 clinical trials are investigating the effects of autophagy inhibition in combination with cytotoxic chemotherapies and targeted agents in various cancers. In this review, we will discuss the role, molecular mechanism, and regulation of autophagy, while targeting this process as a novel therapeutic modality, in various cancers. Keywords: autophagy inhibition, chemotherapy, tumor microenvironment

  10. Autophagy and Transporter-Based Multi-Drug Resistance

    Directory of Open Access Journals (Sweden)

    Zhe-Sheng Chen

    2012-08-01

    Full Text Available All the therapeutic strategies for treating cancers aim at killing the cancer cells via apoptosis (programmed cell death type I. Defective apoptosis endow tumor cells with survival. The cell can respond to such defects with autophagy. Autophagy is a cellular process by which cytoplasmic material is either degraded to maintain homeostasis or recycled for energy and nutrients in starvation. A plethora of evidence has shown that the role of autophagy in tumors is complex. A lot of effort is needed to underline the functional status of autophagy in tumor progression and treatment, and elucidate how to tweak autophagy to treat cancer. Furthermore, during the treatment of cancer, the limitation for the cure rate and survival is the phenomenon of multi drug resistance (MDR. The development of MDR is an intricate process that could be regulated by drug transporters, enzymes, anti-apoptotic genes or DNA repair mechanisms. Reports have shown that autophagy has a dual role in MDR. Furthermore, it has been reported that activation of a death pathway may overcome MDR, thus pointing the importance of other death pathways to regulate tumor cell progression and growth. Therefore, in this review we will discuss the role of autophagy in MDR tumors and a possible link amongst these phenomena.

  11. IFNB1/interferon-ß-induced autophagy in MCF-7 breast cancer cells counteracts its proapoptotic function

    DEFF Research Database (Denmark)

    Ambjørn, Malene; Ejlerskov, Patrick; Liu, Yawei;

    2013-01-01

    of survival pathways leading to treatment resistance. Defects in autophagy, a conserved cellular degradation pathway, are implicated in numerous cancer diseases. Autophagy is induced in response to cancer therapies and can contribute to treatment resistance. While the type II IFN, IFNG, which in many aspects...... differs significantly from type I IFNs, can induce autophagy, no such function for any type I IFN has been reported. We show here that IFNB1 induces autophagy in MCF-7, MDAMB231 and SKBR3 breast cancer cells by measuring the turnover of two autophagic markers, MAP1LC3B/LC3 and SQSTM1/p62. The induction...... of autophagy in MCF-7 cells occurred upstream of the negative regulator of autophagy MTORC1, and autophagosome formation was dependent on the known core autophagy molecule ATG7 and the IFNB1 signaling molecule STAT1. Using siRNA-mediated silencing of several core autophagy molecules and STAT1, we provide...

  12. Astemizole-Histamine induces Beclin-1-independent autophagy by targeting p53-dependent crosstalk between autophagy and apoptosis.

    Science.gov (United States)

    Jakhar, Rekha; Paul, Souren; Bhardwaj, Monika; Kang, Sun Chul

    2016-03-01

    Apoptosis and autophagy are genetically regulated, evolutionarily conserved processes that can jointly seal cancer cell fates, and numerous death stimuli are capable of activating either pathway. Although crosstalk between apoptosis and autophagy is quite complex and sometimes contradictory, it remains a key factor determining the outcomes of death-related pathologies such as cancer. In the present study, exposure of MCF-7 breast cancer cells to HIS and the H1 receptor antagonist AST both alone and together with HIS (AST-HIS) led to generation of intracellular ROS, which induced massive cellular vacuolization through dilation of the ER and mitochondria. Consequently, apoptosis by Bax translocation, cytochrome c release, and caspase activation were triggered. In addition, AST-HIS caused ER stress-induced autophagy in MCF-7 cells, as evidenced by an increased LC3-II/LC3-I ratio, with surprisingly no changes in Beclin-1 expression. Non-canonical autophagy was induced via p53 phosphorylation, which increased p53-p62 interactions to enhance Beclin-1-independent autophagy as evidenced by immunocytochemistry and immunoprecipitation. In the absence of Beclin-1, enhanced autophagy further activated apoptosis through caspase induction. In conclusion, these findings indicate that AST-HIS-induced apoptosis and autophagy can be regulated by ROS-mediated signaling pathways. PMID:26739061

  13. N-acetylcysteine attenuates ischemia-reperfusion-induced apoptosis and autophagy in mouse liver via regulation of the ROS/JNK/Bcl-2 pathway.

    Directory of Open Access Journals (Sweden)

    Chengfen Wang

    Full Text Available BACKGROUND: Hepatic ischemia-reperfusion injury (HIRI remains a pivotal clinical problem after hemorrhagic shock, transplantation, and some types of toxic hepatic injury. Apoptosis and autophagy play important roles in cell death during HIRI. It is also known that N-acetylcysteine (NAC has significant pharmacologic effects on HIRI including elimination of reactive oxygen species (ROS and attenuation of hepatic apoptosis. However, the effects of NAC on HIRI-induced autophagy have not been reported. In this study, we evaluated the effects of NAC on autophagy and apoptosis in HIRI, and explored the possible mechanism involved. METHODS: A mouse model of segmental (70% hepatic warm ischemia was adopted to determine hepatic injury. NAC (150 mg/kg, a hepatoprotection agent, was administered before surgery. We hypothesized that the mechanism of NAC may involve the ROS/JNK/Bcl-2 pathway. We evaluated the expression of JNK, P-JNK, Bcl-2, Beclin 1 and LC3 by western blotting and immunohistochemical staining. Autophagosomes were evaluated by transmission electron microscopy (TEM. RESULTS: We found that ALT, AST and pathological changes were significantly improved in the NAC group. Western blotting analysis showed that the expression levels of Beclin 1 and LC3 were significantly decreased in NAC-treated mice. In addition, JNK, p-JNK, Bax, TNF-α, NF-κB, IL2, IL6 and levels were also decreased in NAC-treated mice. CONCLUSION: NAC can prevent HIRI-induced autophagy and apoptosis by influencing the JNK signal pathway. The mechanism is likely to involve attenuation of JNK and p-JNK via scavenged ROS, an indirect increase in Bcl-2 level, and finally an alteration in the balance of Beclin 1 and Bcl-2.

  14. Autophagy in Skeletal Muscle Homeostasis and in Muscular Dystrophies

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    Paolo Bonaldo

    2012-07-01

    Full Text Available Skeletal muscles are the agent of motion and one of the most important tissues responsible for the control of metabolism. The maintenance of muscle homeostasis is finely regulated by the balance between catabolic and anabolic process. Macroautophagy (or autophagy is a catabolic process that provides the degradation of protein aggregation and damaged organelles through the fusion between autophagosomes and lysosomes. Proper regulation of the autophagy flux is fundamental for the homeostasis of skeletal muscles during physiological situations and in response to stress. Defective as well as excessive autophagy is harmful for muscle health and has a pathogenic role in several forms of muscle diseases. This review will focus on the role of autophagy in muscle homeostasis and diseases.

  15. microRNA-101 is a potent inhibitor of autophagy

    DEFF Research Database (Denmark)

    Frankel, Lisa B; Wen, Jiayu; Lees, Michael;

    2011-01-01

    Autophagy is an evolutionarily conserved mechanism of cellular self-digestion in which proteins and organelles are degraded through delivery to lysosomes. Defects in this process are implicated in numerous human diseases including cancer. To further elucidate regulatory mechanisms of autophagy, we...... performed a functional screen in search of microRNAs (miRNAs), which regulate the autophagic flux in breast cancer cells. In this study, we identified the tumour suppressive miRNA, miR-101, as a potent inhibitor of basal, etoposide- and rapamycin-induced autophagy. Through transcriptome profiling, we...... identified three novel miR-101 targets, STMN1, RAB5A and ATG4D. siRNA-mediated depletion of these genes phenocopied the effect of miR-101 overexpression, demonstrating their importance in autophagy regulation. Importantly, overexpression of STMN1 could partially rescue cells from miR-101-mediated inhibition...

  16. Autophagy research: Lessons from metabolism

    NARCIS (Netherlands)

    A.J. Meijer

    2009-01-01

    Autophagy research continues to expand exponentially. Clearly autophagy and metabolism are intimately connected; however, the rapid expansion of research into this topic inevitably brings the risk that important basic knowledge of metabolism will be overlooked when considering experimental data. Unf

  17. Autophagy as a Potential Target for Sarcopenia.

    Science.gov (United States)

    Fan, Jingjing; Kou, Xianjuan; Jia, Shaohui; Yang, Xiaoqi; Yang, Yi; Chen, Ning

    2016-07-01

    Sarcopenia is an aging-related disease with a significant reduction in mass and strength of skeletal muscle due to the imbalance between protein synthesis and protein degradation. The loss of skeletal muscle is an inevitable event during aging process, which can result in the significant impact on the quality of life, and also can increase the risk for other aging-associated diseases in the elderly. However, the underlying molecular mechanism of aging-related skeletal muscle loss is still poorly understood. Autophagy is a degradation pathway for the clearance of dysfunctional organelles and damaged macromolecules during aging process. Appropriate induction or accurate regulation of autophagic process and improved quality control of mitochondria through autophagy or other strategies are required for the maintenance of skeletal muscle mass. In this article, we have summarized the current understanding of autophagic pathways in sarcopenia, and discussed the functional status of autophagy and autophagy-associated quality control of mitochondria in the pathogenesis of sarcopenia. Moreover, this article will provide some theoretical references for the exploration of scientific and optimal intervention strategies such as exercise and caloric restriction for the prevention and treatment of sarcopenia through the regulation of autophagic pathways. PMID:26580995

  18. Calcium Homeostasis and ER Stress in Control of Autophagy in Cancer Cells

    Directory of Open Access Journals (Sweden)

    Elżbieta Kania

    2015-01-01

    Full Text Available Autophagy is a basic catabolic process, serving as an internal engine during responses to various cellular stresses. As regards cancer, autophagy may play a tumor suppressive role by preserving cellular integrity during tumor development and by possible contribution to cell death. However, autophagy may also exert oncogenic effects by promoting tumor cell survival and preventing cell death, for example, upon anticancer treatment. The major factors influencing autophagy are Ca2+ homeostasis perturbation and starvation. Several Ca2+ channels like voltage-gated T- and L-type channels, IP3 receptors, or CRAC are involved in autophagy regulation. Glucose transporters, mainly from GLUT family, which are often upregulated in cancer, are also prominent targets for autophagy induction. Signals from both Ca2+ perturbations and glucose transport blockage might be integrated at UPR and ER stress activation. Molecular pathways such as IRE 1-JNK-Bcl-2, PERK-eIF2α-ATF4, or ATF6-XBP 1-ATG are related to autophagy induced through ER stress. Moreover ER molecular chaperones such as GRP78/BiP and transcription factors like CHOP participate in regulation of ER stress-mediated autophagy. Autophagy modulation might be promising in anticancer therapies; however, it is a context-dependent matter whether inhibition or activation of autophagy leads to tumor cell death.

  19. Phospholipase C-related catalytically inactive protein (PRIP regulates lipolysis in adipose tissue by modulating the phosphorylation of hormone-sensitive lipase.

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    Toshiya Okumura

    Full Text Available Phosphorylation of hormone-sensitive lipase (HSL and perilipin by protein kinase A (PKA promotes the hydrolysis of lipids in adipocytes. Although activation of lipolysis by PKA has been well studied, inactivation via protein phosphatases is poorly understood. Here, we investigated whether phospholipase C-related catalytically inactive protein (PRIP, a binding partner for protein phosphatase 1 and protein phosphatase 2A (PP2A, is involved in lipolysis by regulating phosphatase activity. PRIP knockout (PRIP-KO mice displayed reduced body-fat mass as compared with wild-type mice fed with standard chow ad libitum. Most other organs appeared normal, suggesting that mutant mice had aberrant fat metabolism in adipocytes. HSL in PRIP-KO adipose tissue was highly phosphorylated compared to that in wild-type mice. Starvation of wild-type mice or stimulation of adipose tissue explants with the catabolic hormone, adrenaline, translocated both PRIP and PP2A from the cytosol to lipid droplets, but the translocation of PP2A was significantly reduced in PRIP-KO adipocytes. Consistently, the phosphatase activity associated with lipid droplet fraction in PRIP-KO adipocytes was significantly reduced and was independent of adrenaline stimulation. Lipolysis activity, as assessed by measurement of non-esterified fatty acids and glycerol, was higher in PRIP-KO adipocytes. When wild-type adipocytes were treated with a phosphatase inhibitor, they showed a high lipolysis activity at the similar level to PRIP-KO adipocytes. Collectively, these results suggest that PRIP promotes the translocation of phosphatases to lipid droplets to trigger the dephosphorylation of HSL and perilipin A, thus reducing PKA-mediated lipolysis.

  20. Apolipoprotein E-dependent inverse regulation of vertebral bone and adipose tissue mass in C57Bl/6 mice: modulation by diet-induced obesity.

    Science.gov (United States)

    Bartelt, Alexander; Beil, F Timo; Schinke, Thorsten; Roeser, Kerstin; Ruether, Wolfgang; Heeren, Joerg; Niemeier, Andreas

    2010-10-01

    The long prevailing view that obesity is generally associated with beneficial effects on the skeleton has recently been challenged. Apolipoprotein E (apoE) is known to influence both adipose tissue and bone. The goal of the current study was to examine the impact of apoE on the development of fat mass and bone mass in mice under conditions of diet-induced obesity (DIO). Four week-old male C57BL/6 (WT) and apoE-deficient (apoE(-/-)) mice received a control or a diabetogenic high-fat diet (HFD) for 16 weeks. The control-fed apoE(-/-) animals displayed less total fat mass and higher lumbar trabecular bone volume (BV/TV) than WT controls. When stressed with HFD to induce obesity, apoE(-/-) mice had a lower body weight, lower serum glucose, insulin and leptin levels and accumulated less white adipose tissue mass at all sites including bone marrow. While WT animals showed no significant change in BV/TV and bone formation rate (BFR), apoE deficiency led to a decrease of BV/TV and BFR when stressed with HFD. Bone resorption parameters were not affected by HFD in either genotype. Taken together, under normal dietary conditions, apoE-deficient mice acquire less fat mass and more bone mass than WT littermates. When stressed with HFD to develop DIO, the difference of total body fat mass becomes larger and the difference of bone mass smaller between the genotypes. We conclude that apoE is involved in an inverse regulation of bone mass and fat mass in growing mice and that this effect is modulated by diet-induced obesity. PMID:20633710

  1. Up-regulation of miRNA-221 inhibits hypoxia/reoxygenation-induced autophagy through the DDIT4/mTORC1 and Tp53inp1/p62 pathways.

    Science.gov (United States)

    Chen, Qiying; Zhou, Yue; Richards, A Mark; Wang, Peipei

    2016-05-20

    Timely reperfusion in acute myocardial infarction has improved clinical outcomes but the benefits are partially offset by ischemia-reperfusion injury (I/R). MiRNA regulates mRNA of multiple effectors within injury and survival cell signaling pathways. We have previously reported the protective effects of miRNA-221 in I/R injury. The purpose of this study was to explore the mechanisms underlying cardioprotection of miR-221. Myoblast H9c2 and neonatal rat ventricular myocytes (NRVM) were subjected to 0.2% O2 hypoxia followed by 2 h of re-oxygenation (H/R). In gain-and-loss function studies through transfections of miR-221 mimic (miR-221) and inhibitor (miR-221-i), the protective effects of miR-221 were confirmed as assessed by increased cell metabolic activity (WST-1) and decreased LDH release. Autophagy was assessed by GFP-LC3 labeling of autophagosome formation, LC3 and p62 measurements. Co-immuno-precipitation and specific gene cloning and function were used to identify the pathways underpinning miR-221 effects. MiR-221 significantly reduced H/R injury in association with inhibition of autophagy. Underlying mechanisms include (1) down-regulation of Ddit4 (disinhibiting the mTORC1/p-4EBP1 pathway) which inhibits autophagosome formation (2) down-regulation of Tp53inp1 (with reduced Tp53inp1/p62 complex formation) which inhibits autophagosome degradation. In conclusion, miRNA-221 exerts cytoprotective effects in hypoxia-reoxygenation injury in association with alterations in autophagic cell injury. Mir-221 may constitute is a novel therapeutic target in the treatment of cardiac I/R injury. PMID:27105917

  2. Targeting Adipose Tissue Lipid Metabolism to Improve Glucose Metabolism in Cardiometabolic Disease

    Directory of Open Access Journals (Sweden)

    Johan W.E. Jocken

    2014-10-01

    Full Text Available With Type 2 diabetes mellitus and cardiovascular disease prevalence on the rise, there is a growing need for improved strategies to prevent or treat obesity and insulin resistance, both of which are major risk factors for these chronic diseases. Impairments in adipose tissue lipid metabolism seem to play a critical role in these disorders. In the classical picture of intracellular lipid breakdown, cytosolic lipolysis was proposed as the sole mechanism for triacylglycerol hydrolysis in adipocytes. Recent evidence suggests involvement of several hormones, membrane receptors, and intracellular signalling cascades, which has added complexity to the regulation of cytosolic lipolysis. Interestingly, a specific form of autophagy, called lipophagy, has been implicated as alternative lipolytic pathway. Defective regulation of cytosolic lipolysis and lipophagy might have substantial effects on lipid metabolism, thereby contributing to adipose tissue dysfunction, insulin resistance, and related cardiometabolic (cMet diseases. This review will discuss recent advances in our understanding of classical lipolysis and lipophagy in adipocyte lipid metabolism under normal and pathological conditions. Furthermore, the question of whether modulation of adipocyte lipolysis and lipophagy might be a potential therapeutic target to combat cMet disorders will be addressed.

  3. Receptor Proteins in Selective Autophagy

    Directory of Open Access Journals (Sweden)

    Christian Behrends

    2012-01-01

    Full Text Available Autophagy has long been thought to be an essential but unselective bulk degradation pathway. However, increasing evidence suggests selective autophagosomal turnover of a broad range of substrates. Bifunctional autophagy receptors play a key role in selective autophagy by tethering cargo to the site of autophagosomal engulfment. While the identity of molecular components involved in selective autophagy has been revealed at least to some extent, we are only beginning to understand how selectivity is achieved in this process. Here, we summarize the mechanistic and structural basis of receptor-mediated selective autophagy.

  4. Regulation of adipogenesis by paracrine factors from adipose stromal-vascular fraction - a link to fat depot-specific differences.

    Science.gov (United States)

    Meissburger, Bettina; Perdikari, Aliki; Moest, Hansjörg; Müller, Sebastian; Geiger, Matthias; Wolfrum, Christian

    2016-09-01

    Visceral and subcutaneous adipose tissue depots have distinct features and contribute differentially to the development of metabolic dysfunction. We show here that adipocyte differentiation in subcutaneous stromal-vascular fraction (SVF) is increased compared to visceral SVF, however this increased differentiation capacity seems not to be due to changes in the number of adipocyte precursor cells. Rather, we demonstrate that secreted heat-sensitive factors from the SVF can inhibit adipocyte differentiation and that this effect is higher in visceral than in subcutaneous SVF, suggesting that visceral SVF is a source of secreted factors that can inhibit adipocyte formation. In order to explore secreted proteins that potentially inhibit differentiation in visceral preadipocytes we analyzed the secretome of both SVFs which led to the identification of 113 secreted proteins with an overlap of 42%. Further expression analysis in both depots revealed 16 candidates that were subsequently analyzed in a differentiation screen using an adenoviral knockdown system. From this analysis we were able to identify two potential inhibitory candidates, namely decorin (Dcn) and Sparc-like 1 (Sparcl1). We could show that ablation of either candidate enhanced adipogenesis in visceral preadipocytes, while treatment of primary cultures with recombinant Sparcl1 and Dcn blocked adipogenesis in a dose dependent manner. In conclusion, our data suggests that the differences in adipogenesis between depots might be due to paracrine and autocrine feedback mechanisms which could in turn contribute to metabolic homeostasis. PMID:27317982

  5. Metabolic Regulation of Adipose Tissue on Reproduction%脂肪组织对繁殖的代谢调控

    Institute of Scientific and Technical Information of China (English)

    冯冬冬; 姚海莉; 贺小卫; 杜亚轩; 左晓梅

    2012-01-01

    脂肪组织可以分泌一系列激素和细胞因子,广泛参与机体的能量代谢、免疫和炎症反应、发育和生殖等生理、病理活动。瘦素、脂联素和抵抗素被认为是重要的脂肪分泌因子,可能在介导能量代谢状态、神经内分泌轴及繁殖的过程中发挥重要作用。%The adipose tissue can secrete hormones and gy metabolism, immune and inflammatory responses, develop logical activities. Leptin, adiponectin and resistin was consid tissue, and may play an important role in the process of inte crine axis and reproduction. cytokines, which participate widely in the body's enerment, reproduction and other physiological and pathoered to be important factors which secreted by dipose raction between energy metabolic and the neuroendocrine axis and reproduction.

  6. Oxidative stress in mouse sperm impairs embryo development, fetal growth and alters adiposity and glucose regulation in female offspring.

    Directory of Open Access Journals (Sweden)

    Michelle Lane

    Full Text Available Paternal health cues are able to program the health of the next generation however the mechanism for this transmission is unknown. Reactive oxygen species (ROS are increased in many paternal pathologies, some of which program offspring health, and are known to induce DNA damage and alter the methylation pattern of chromatin. We therefore investigated whether a chemically induced increase of ROS in sperm impairs embryo, pregnancy and offspring health. Mouse sperm was exposed to 1500 µM of hydrogen peroxide (H2O2, which induced oxidative damage, however did not affect sperm motility or the ability to bind and fertilize an oocyte. Sperm treated with H2O2 delayed on-time development of subsequent embryos, decreased the ratio of inner cell mass cells (ICM in the resulting blastocyst and reduced implantation rates. Crown-rump length at day 18 of gestation was also reduced in offspring produced by H2O2 treated sperm. Female offspring from H2O2 treated sperm were smaller, became glucose intolerant and accumulated increased levels of adipose tissue compared to control female offspring. Interestingly male offspring phenotype was less severe with increases in fat depots only seen at 4 weeks of age, which was restored to that of control offspring later in life, demonstrating sex-specific impacts on offspring. This study implicates elevated sperm ROS concentrations, which are common to many paternal health pathologies, as a mediator of programming offspring for metabolic syndrome and obesity.

  7. The role of autophagy in lung ischemia/reperfusion injury after lung transplantation in rats

    Science.gov (United States)

    Liu, Sheng; Zhang, Jun; Yu, Bentong; Huang, Lei; Dai, Bin; Liu, Jichun; Tang, Jian

    2016-01-01

    Background: The aim of this study was to explore the role of autophagy in the cold I/R injury following lung transplantation. Methods: The rat orthotopic lung transplantation model was established to perform the level of autophagy in the cold I/R injury in this study. The pretreatment of inhibitor (3-Methyladenine [3-MA]) and activator (rapamycin [RAPA]) of autophagy were performed to assess the role of autophagy in the cold I/R injury following lung transplantation in rats. Results: After lung transplantation, the autophagy, lung cell apoptosis and lung injury were aggravated and peaked at 6 h following the transplantation. The inhibition of autophagy by 3-MA induced downregulated of autophagy, decreased cell apoptosis. Meanwhile, the lung injury, which was indicated by calculating the peak inspiratory pressure (PIP), pulmonary vein blood gas analysis (PO2) and ratio of wet to dry in lung (W/D), was ameliorated after treatment with 3-MA. The activation of autophagy by RAPA causing the upregulated of autophagy and apoptosis of lung cells, and enhanced the lung injury. Conclusion: All the results suggested that the autophagy was involved in the cold I/R injury in lung transplantation model, and played a potential role on the regulation of I/R injury after lung transplantation. PMID:27648150

  8. Hepatitis B virus x protein induces autophagy via activating death-associated protein kinase.

    Science.gov (United States)

    Zhang, H-T; Chen, G G; Hu, B-G; Zhang, Z-Y; Yun, J-P; He, M-L; Lai, P B S

    2014-01-01

    Hepatitis B virus x protein (HBX), a product of hepatitis B virus (HBV), is a multifunctional protein that regulates viral replication and various cellular functions. Recently, HBX has been shown to induce autophagy; however, the responsible mechanism is not fully known. In this study, we established stable HBX-expressing epithelial Chang cells as the platform to study how HBX induced autophagy. The results showed that the overexpression of HBX resulted in starvation-induced autophagy. HBX-induced autophagy was related to its ability to dephosphorylate/activate death-associated protein kinase (DAPK). The block of DAPK by its siRNA significantly counteracted HBX-mediated autophagy, confirming the positive role of DAPK in this process. HBX also induced Beclin 1, which functions at the downstream of the DAPK-mediated autophagy pathway. Although HBX could activate JNK, a kinase known to participate in autophagy in certain conditions, the change in JNK failed to influence HBX-induced autophagy. In conclusion, HBX induces autophagy via activating DAPK in a pathway related to Beclin 1, but not JNK. This new finding should help us to understand the role of autophagy in HBX-mediated pathogenesis and thus may provide targets for intervening HBX-related disorders.

  9. Minireview: adiposity, inflammation, and atherogenesis.

    Science.gov (United States)

    Lyon, Christopher J; Law, Ronald E; Hsueh, Willa A

    2003-06-01

    Adipose tissue is a dynamic endocrine organ that secretes a number of factors that are increasingly recognized to contribute to systemic and vascular inflammation. Several of these factors, collectively referred to as adipokines, have now been shown regulate, directly or indirectly, a number of the processes that contribute to the development of atherosclerosis, including hypertension, endothelial dysfunction, insulin resistance, and vascular remodeling. Several adipokines are preferentially expressed in visceral adipose tissue, and the secretion of proinflammatory adipokines is elevated with increasing adiposity. Not surprisingly, approaches that reduce adipose tissue depots, including surgical fat removal, exercise, and reduced caloric intake, improve proinflammatory adipokine levels and reduce the severity of their resultant pathologies. Systemic adipokine levels can also be favorably altered by treatment with several of the existing drug classes used to treat insulin resistance, hypertension, and hypercholesterolemia. Greater understanding of adipokine regulation, however, should result in the design of improved treatment strategies to control disease states associated with increase adiposity, an important outcome in view of the growing worldwide epidemic of obesity. PMID:12746274

  10. Interactions between Autophagy and Bacterial Toxins: Targets for Therapy?

    Science.gov (United States)

    Mathieu, Jacques

    2015-08-04

    Autophagy is a physiological process involved in defense mechanisms for clearing intracellular bacteria. The autophagic pathway is finely regulated and bacterial toxins interact with this process in a complex manner. Bacterial toxins also interact significantly with many biochemical processes. Evaluations of the effects of bacterial toxins, such as endotoxins, pore-forming toxins and adenylate cyclases, on autophagy could support the development of new strategies for counteracting bacterial pathogenicity. Treatment strategies could focus on drugs that enhance autophagic processes to improve the clearance of intracellular bacteria. However, further in vivo studies are required to decipher the upregulation of autophagy and potential side effects limiting such approaches. The capacity of autophagy activation strategies to improve the outcome of antibiotic treatment should be investigated in the future.

  11. Glucocorticoids induce autophagy in rat bone marrow mesenchymal stem cells

    DEFF Research Database (Denmark)

    Wang, L.; Fan, J.; Lin, Y. S.;

    2015-01-01

    Glucocorticoidinduced osteoporosis (GIOP) is a widespread clinical complication following glucocorticoid therapy. This irreversible damage to boneforming and resorbing cells is essential in the pathogenesis of osteoporosis. Autophagy is a physiological process involved in the regulation of cells...... and their responses to diverse stimuli, however, the role of autophagy in glucocorticoidinduced damage to bone marrow mesenchymal stem cells (BMSCs) remains unclear. The current study confirmed that glucocorticoid administration impaired the proliferation of BMSCs. Transmission electron microscopy......, immunohistochemistry and western blot analysis detected autophagy in vitro and in GIOP model rats (in vivo). With the addition of the autophagy inhibitor 3methyladenine, the proliferative ability of BMSCs was further reduced, while the number of apoptotic BMSCs was significantly increased. The data suggests...

  12. Interactions between Autophagy and Bacterial Toxins: Targets for Therapy?

    Directory of Open Access Journals (Sweden)

    Jacques Mathieu

    2015-08-01

    Full Text Available Autophagy is a physiological process involved in defense mechanisms for clearing intracellular bacteria. The autophagic pathway is finely regulated and bacterial toxins interact with this process in a complex manner. Bacterial toxins also interact significantly with many biochemical processes. Evaluations of the effects of bacterial toxins, such as endotoxins, pore-forming toxins and adenylate cyclases, on autophagy could support the development of new strategies for counteracting bacterial pathogenicity. Treatment strategies could focus on drugs that enhance autophagic processes to improve the clearance of intracellular bacteria. However, further in vivo studies are required to decipher the upregulation of autophagy and potential side effects limiting such approaches. The capacity of autophagy activation strategies to improve the outcome of antibiotic treatment should be investigated in the future.

  13. Interplay between the cellular autophagy machinery and positive-stranded RNA viruses

    Institute of Scientific and Technical Information of China (English)

    Junyan Shi; Honglin Luo

    2012-01-01

    Autophagy is a conserved cellular process that acts as a key regulator in maintaining cellular homeostasis.Recent studies implicate an important role for autophagy in infection and immunity by removing invading pathogens and through modulating innate and adaptive immune responses.However,several pathogens,notably some positive-stranded RNA viruses,have subverted autophagy to their own ends.In this review,we summarize the current understanding of how viruses with a positive-stranded RNA genome interact with the host autophagy machinery to control their replication and spread.We review the mechanisms underlying the induction of autophagy and discuss the pro- and anti-viral functions of autophagy and the potential mechanisms involved.

  14. Mechanisms of autophagy and apoptosis:Recent developments in breast cancer cells

    Institute of Scientific and Technical Information of China (English)

    Juan; M; Esteve; Erwin; Knecht

    2011-01-01

    Autophagy,the pathway whereby cell components are degraded by lysosomes,is involved in the cell response to environmental stresses,such as nutrient deprivation,hypoxia or exposition to chemotherapeutic agents.Under these conditions,which are reminiscent of certain phases of tumor development,autophagy either promotes cell survival or induces cell death. This strengthens the possibility that autophagy could be an important target in cancer therapy,as has been proposed.Here,we describe the regulation of survival and death by autophagy and apoptosis,especially in cultured breast cancer cells.In particular,we discuss whether autophagy represents an apoptosis-independent process and/or if they share common pathways. We believe that understanding in detail the molecular mechanisms that underlie the relationships between autophagy and apoptosis in breast cancer cells could improve the available treatments for this disease.

  15. Cinnamon extract regulates plasma levels of adipose-derived factors and expression of multiple genes related to carbohydrate metabolism and lipogenesis in adipose tissue of fructose-fed rats

    Science.gov (United States)

    We reported previously that a dietary cinnamon extract (CE) improves systemic insulin sensitivity and dyslipidemia by enhancing insulin signaling. In the present study, we examined the effects of CE on several biomarkers including plasma levels of adipose-derived adipokines, and the potential molec...

  16. A role for autophagy in the extension of lifespan by dietary restriction in C. elegans.

    Directory of Open Access Journals (Sweden)

    Malene Hansen

    2008-02-01

    Full Text Available In many organisms, dietary restriction appears to extend lifespan, at least in part, by down-regulating the nutrient-sensor TOR (Target Of Rapamycin. TOR inhibition elicits autophagy, the large-scale recycling of cytoplasmic macromolecules and organelles. In this study, we asked whether autophagy might contribute to the lifespan extension induced by dietary restriction in C. elegans. We find that dietary restriction and TOR inhibition produce an autophagic phenotype and that inhibiting genes required for autophagy prevents dietary restriction and TOR inhibition from extending lifespan. The longevity response to dietary restriction in C. elegans requires the PHA-4 transcription factor. We find that the autophagic response to dietary restriction also requires PHA-4 activity, indicating that autophagy is a transcriptionally regulated response to food limitation. In spite of the rejuvenating effect that autophagy is predicted to have on cells, our findings suggest that autophagy is not sufficient to extend lifespan. Long-lived daf-2 insulin/IGF-1 receptor mutants require both autophagy and the transcription factor DAF-16/FOXO for their longevity, but we find that autophagy takes place in the absence of DAF-16. Perhaps autophagy is not sufficient for lifespan extension because although it provides raw material for new macromolecular synthesis, DAF-16/FOXO must program the cells to recycle this raw material into cell-protective longevity proteins.

  17. Adipose Tissue Biology: An Update Review

    Directory of Open Access Journals (Sweden)

    Anna Meiliana

    2009-12-01

    Full Text Available BACKGROUND: Obesity is a major health problem in most countries in the world today. It increases the risk of diabetes, heart disease, fatty liver and some form of cancer. Adipose tissue biology is currently one of the “hot” areas of biomedical science, as fundamental for the development of novel therapeutics for obesity and its related disorders.CONTENT: Adipose tissue consist predominantly of adipocytes, adipose-derived stromal cells (ASCs, vascular endothelial cells, pericytes, fibroblast, macrophages, and extracellular matrix. Adipose tissue metabolism is extremely dynamic, and the supply of and removal of substrates in the blood is acutely regulated according to the nutritional state. Adipose tissue possesses the ability to a very large extent to modulate its own metabolic activities including differentiation of new adipocytes and production of blood vessels as necessary to accommodate increasing fat stores. At the same time, adipocytes signal to other tissue to regulate their energy metabolism in accordance with the body's nutritional state. Ultimately adipocyte fat stores have to match the body's overall surplus or deficit of energy. Obesity causes adipose tissue dysfunction and results in obesity-related disorders. SUMMARY: It is now clear that adipose tissue is a complex and highly active metabolic and endocrine organ. Undestanding the molecular mechanisms underlying obesity and its associated disease cluster is also of great significance as the need for new and more effective therapeutic strategies is more urgent than ever.  KEYWORDS: obesity, adipocyte, adipose, tissue, adipogenesis, angiogenesis, lipid droplet, lipolysis, plasticity, dysfunction.

  18. DNA damage and autophagy

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Rocha, Humberto; Garcia-Garcia, Aracely [Redox Biology Center and School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583 (United States); Panayiotidis, Mihalis I. [School of Community Health Sciences, University of Nevada, Reno, NV 89557 (United States); Franco, Rodrigo, E-mail: rfrancocruz2@unl.edu [Redox Biology Center and School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583 (United States)

    2011-06-03

    Both exogenous and endogenous agents are a threat to DNA integrity. Exogenous environmental agents such as ultraviolet (UV) and ionizing radiation, genotoxic chemicals and endogenous byproducts of metabolism including reactive oxygen species can cause alterations in DNA structure (DNA damage). Unrepaired DNA damage has been linked to a variety of human disorders including cancer and neurodegenerative disease. Thus, efficient mechanisms to detect DNA lesions, signal their presence and promote their repair have been evolved in cells. If DNA is effectively repaired, DNA damage response is inactivated and normal cell functioning resumes. In contrast, when DNA lesions cannot be removed, chronic DNA damage triggers specific cell responses such as cell death and senescence. Recently, DNA damage has been shown to induce autophagy, a cellular catabolic process that maintains a balance between synthesis, degradation, and recycling of cellular components. But the exact mechanisms by which DNA damage triggers autophagy are unclear. More importantly, the role of autophagy in the DNA damage response and cellular fate is unknown. In this review we analyze evidence that supports a role for autophagy as an integral part of the DNA damage response.

  19. Dopamine Oxidation and Autophagy

    Directory of Open Access Journals (Sweden)

    Patricia Muñoz

    2012-01-01

    Full Text Available The molecular mechanisms involved in the neurodegenerative process of Parkinson's disease remain unclear. Currently, there is a general agreement that mitochondrial dysfunction, α-synuclein aggregation, oxidative stress, neuroinflammation, and impaired protein degradation are involved in the neurodegeneration of dopaminergic neurons containing neuromelanin in Parkinson's disease. Aminochrome has been proposed to play an essential role in the degeneration of dopaminergic neurons containing neuromelanin by inducing mitochondrial dysfunction, oxidative stress, the formation of neurotoxic α-synuclein protofibrils, and impaired protein degradation. Here, we discuss the relationship between the oxidation of dopamine to aminochrome, the precursor of neuromelanin, autophagy dysfunction in dopaminergic neurons containing neuromelanin, and the role of dopamine oxidation to aminochrome in autophagy dysfunction in dopaminergic neurons. Aminochrome induces the following: (i the formation of α-synuclein protofibrils that inactivate chaperone-mediated autophagy; (ii the formation of adducts with α- and β-tubulin, which induce the aggregation of the microtubules required for the fusion of autophagy vacuoles and lysosomes.

  20. Autophagy studies in Bombyx mori

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    L Tian

    2015-03-01

    Full Text Available Autophagy, which is well conserved from yeast to mammals, plays essential roles in development and diseases. Using the domesticated silkworm, Bombyx mori, as a model insect, several reports on autophagy have been made recently. Autophagic features are observed in the midgut and fat body during the larval-pupal transition as well as the silk gland and ovarian nurse cells during the pupal stage. There are 14 autophagy related (Atg genes, including at least two transcript variants of Atg1, predicated in Bombyx. Expression of most Atg genes is consistent with the autophagy process in the fat body during the larval-pupal transition, and reduction of Atg1 expression by RNAi blocks this process. The molting hormone, 20-hydroxyecdysone (20E, and starvation induce autophagy in the fat body by upregulating Atg gene expression and blocking the PI3K-TORC1 pathway. Meanwhile, autophagy precedes apoptosis in the midgut and other larval tissues during the larval-pupal transition, while the detailed mechanism is not illustrated yet. We assume that there are at least four future directions about autophagy studies in Bombyx during the next years: (1 physiological functions of autophagy; (2 identification of new components involved in the autophagy process; (3 detailed molecular mechanism of autophagosome formation; (4 functional relationship between autophagy and apoptosis.

  1. miR-34a inhibits differentiation of human adipose tissue-derived stem cells by regulating cell cycle and senescence induction.

    Science.gov (United States)

    Park, Ho; Park, Hyeon; Pak, Ha-Jin; Yang, Dong-Yun; Kim, Yun-Hong; Choi, Won-Jun; Park, Se-Jin; Cho, Jung-Ah; Lee, Kyo-Won

    2015-01-01

    MicroRNAs (miRNAs) are critical in the maintenance, differentiation, and lineage commitment of stem cells. Stem cells have the unique property to differentiate into tissue-specific cell types (lineage commitment) during cell division (self-renewal). In this study, we investigated whether miR-34a, a cell cycle-regulating microRNA, could control the stem cell properties of adipose tissue-derived stem cells (ADSCs). First, we found that the expression level of miR-34a was increased as the cell passage number was increased. This finding, however, was inversely correlated with our finding that the overexpression of miR-34a induced the decrease of cell proliferation. In addition, miR-34a overexpression decreased the expression of various cell cycle regulators such as CDKs (-2, -4, -6) and cyclins (-E, -D), but not p21 and p53. The cell cycle analysis showed accumulation of dividing cells at S phase by miR-34a, which was reversible by co-treatment with anti-miR-34a. The potential of adipogenesis and osteogenesis of ADSCs was also decreased by miR-34a overexpression, which was recovered by co-treatment with anti-miR-34a. The surface expression of stem cell markers including CD44 was also down-regulated by miR-34a overexpression as similar to that elicited by cell cycle inhibitors. miR-34a also caused a significant decrease in mRNA expression of stem cell transcription factors as well as STAT-3 expression and phosphorylation. Cytokine profiling revealed that miR-34a significantly modulated IL-6 and -8 production, which was strongly related to cellular senescence. These data suggest the importance of miR-34a for the fate of ADSCs toward senescence rather than differentiation.

  2. Adipose-Derived Stem Cells

    DEFF Research Database (Denmark)

    Toyserkani, Navid Mohamadpour; Quaade, Marlene Louise; Sheikh, Søren Paludan;

    2015-01-01

    Emerging evidence has shown that adipose tissue is the richest and most accessible source of mesenchymal stem cells. Many different therapies for chronic wounds exist with varying success rates. The capacity of adipose-derived stem cells (ASCs) to promote angiogenesis, secrete growth factors......, regulate the inflammatory process, and differentiate into multiple cell types makes them a potential ideal therapy for chronic wounds. The aim of this article was to review all preclinical trials using ASCs in problem wound models. A systematic search was performed and 12 studies were found where different...

  3. Tightly regulated and homogeneous transgene expression in human adipose-derived mesenchymal stem cells by lentivirus with tet-off system.

    Directory of Open Access Journals (Sweden)

    Hiroyuki Moriyama

    Full Text Available Genetic modification of human adipose tissue-derived multilineage progenitor cells (hADMPCs is highly valuable for their exploitation in therapeutic applications. Here, we have developed a novel single tet-off lentiviral vector platform. This vector combines (1 a modified tetracycline (tet-response element composite promoter, (2 a multi-cistronic strategy to express an improved version of the tet-controlled transactivator and the blasticidin resistance gene under the control of a ubiquitous promoter, and (3 acceptor sites for easy recombination cloning of the gene of interest. In the present study, we used the cytomegalovirus (CMV or the elongation factor 1 α (EF-1α promoter as the ubiquitous promoter, and EGFP was introduced as the gene of interest. hADMPCs transduced with a lentiviral vector carrying either the CMV promoter or the EF-1α promoter were effectively selected by blasticidin without affecting their stem cell properties, and EGFP expression was strictly regulated by doxycycline (Dox treatment in these cells. However, the single tet-off lentiviral vector carrying the EF-1α promoter provided more homogenous expression of EGFP in hADMPCs. Intriguingly, differentiated cells from these Dox-responsive cell lines constitutively expressed EGFP only in the absence of Dox. This single tet-off lentiviral vector thus provides an important tool for applied research on hADMPCs.

  4. Cathepsin-D, a key protease in breast cancer, is up-regulated in obese mouse and human adipose tissue, and controls adipogenesis.

    Directory of Open Access Journals (Sweden)

    Olivier Masson

    Full Text Available The aspartic protease cathepsin-D (cath-D is overexpressed by human epithelial breast cancer cells and is closely correlated with poor prognosis in breast cancer. The adipocyte is one of the most prominent cell types in the tumor-microenvironment of breast cancer, and clinical studies have shown that obesity increases the incidence of breast cancer. Here, we provide the first evidence that cath-D expression is up-regulated in adipose tissue from obese human beings, as well as in adipocytes from the obese C57BI6/J mouse. Cath-D expression is also increased during human and mouse adipocyte differentiation. We show that cath-D silencing in 3T3-F442A murine preadipocytes leads to lipid-depleted cells after adipogenesis induction, and inhibits of the expression of PPARγ, HSL and aP2 adipocyte differentiation markers. Altogether, our findings demonstrate the key role of cath-D in the control of adipogenesis, and suggest that cath-D may be a novel target in obesity.

  5. Autophagy deficiency in myeloid cells increases susceptibility to obesity-induced diabetes and experimental colitis.

    Science.gov (United States)

    Lee, Hae-Youn; Kim, Jinyoung; Quan, Wenying; Lee, June-Chul; Kim, Min-Soo; Kim, Seok-Hyung; Bae, Jin-Woo; Hur, Kyu Yeon; Lee, Myung-Shik

    2016-08-01

    Autophagy, which is critical for the proper turnover of organelles such as endoplasmic reticulum and mitochondria, affects diverse aspects of metabolism, and its dysregulation has been incriminated in various metabolic disorders. However, the role of autophagy of myeloid cells in adipose tissue inflammation and type 2 diabetes has not been addressed. We produced mice with myeloid cell-specific deletion of Atg7 (autophagy-related 7), an essential autophagy gene (Atg7 conditional knockout [cKO] mice). While Atg7 cKO mice were metabolically indistinguishable from control mice, they developed diabetes when bred to ob/w mice (Atg7 cKO-ob/ob mice), accompanied by increases in the crown-like structure, inflammatory cytokine expression and inflammasome activation in adipose tissue. Mφs (macrophages) from Atg7 cKO mice showed significantly higher interleukin 1 β release and inflammasome activation in response to a palmitic acid plus lipopolysaccharide combination. Moreover, a decrease in the NAD(+):NADH ratio and increase in intracellular ROS content after treatment with palmitic acid in combination with lipopolysaccharide were more pronounced in Mφs from Atg7 cKO mice, suggesting that mitochondrial dysfunction in autophagy-deficient Mφs leads to an increase in lipid-induced inflammasome and metabolic deterioration in Atg7 cKO-ob/ob mice. Atg7 cKO mice were more susceptible to experimental colitis, accompanied by increased colonic cytokine expression, T helper 1 skewing and systemic bacterial invasion. These results suggest that autophagy of Mφs is important for the control of inflammasome activation in response to metabolic or extrinsic stress, and autophagy deficiency in Mφs may contribute to the progression of metabolic syndrome associated with lipid injury and colitis. PMID:27337687

  6. Autophagy During Cardiac Stress: Joys and Frustrations of Autophagy

    Science.gov (United States)

    Gottlieb, Roberta A.; Mentzer, Robert M.

    2013-01-01

    The study of autophagy has been transformed by the cloning of most genes in the pathway and the introduction of GFP-LC3 as a reporter to allow visual assessment of autophagy. The field of cardiac biology is not alone in attempting to understand the implications of autophagy. The purpose of this review is to address some of the controversies and conundrums associated with the evolving studies of autophagy in the heart. Autophagy is a cellular process involving a complex orchestration of regulatory gene products as well as machinery for assembly, selective targeting, and degradation of autophagosomes and their contents. Our understanding of the role of autophagy in human disease is rapidly evolving as investigators examine the process in different tissues and different pathophysiological contexts. In the field of heart disease, autophagy has been examined in the settings of ischemia and reperfusion, preconditioning, cardiac hypertrophy, and heart failure. This review addresses the role of autophagy in cardioprotection, the balance of catabolism and anabolism, the concept of mitochondrial quality control, and the implications of impaired autophagic flux or frustrated autophagy. PMID:20148666

  7. Imaging white adipose tissue with confocal microscopy.

    Science.gov (United States)

    Martinez-Santibañez, Gabriel; Cho, Kae Won; Lumeng, Carey N

    2014-01-01

    Adipose tissue is composed of a variety of cell types that include mature adipocytes, endothelial cells, fibroblasts, adipocyte progenitors, and a range of inflammatory leukocytes. These cells work in concert to promote nutrient storage in adipose tissue depots and vary widely based on location. In addition, overnutrition and obesity impart significant changes in the architecture of adipose tissue that are strongly associated with metabolic dysfunction. Recent studies have called attention to the importance of adipose tissue microenvironments in regulating adipocyte function and therefore require techniques that preserve cellular interactions and permit detailed analysis of three-dimensional structures in fat. This chapter summarizes our experience with the use of laser scanning confocal microscopy for imaging adipose tissue in rodents.

  8. Retinoid receptor signaling and autophagy in acute promyelocytic leukemia

    Energy Technology Data Exchange (ETDEWEB)

    Orfali, Nina [Cork Cancer Research Center, University College Cork, Cork (Ireland); Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065, USA. (United States); McKenna, Sharon L. [Cork Cancer Research Center, University College Cork, Cork (Ireland); Cahill, Mary R. [Department of Hematology, Cork University Hospital, Cork (Ireland); Gudas, Lorraine J., E-mail: ljgudas@med.cornell.edu [Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065, USA. (United States); Mongan, Nigel P., E-mail: nigel.mongan@nottingham.ac.uk [Faculty of Medicine and Health Science, School of Veterinary Medicine and Science, University of Nottingham, LE12 5RD (United Kingdom); Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065, USA. (United States)

    2014-05-15

    Retinoids are a family of signaling molecules derived from vitamin A with well established roles in cellular differentiation. Physiologically active retinoids mediate transcriptional effects on cells through interactions with retinoic acid (RARs) and retinoid-X (RXR) receptors. Chromosomal translocations involving the RARα gene, which lead to impaired retinoid signaling, are implicated in acute promyelocytic leukemia (APL). All-trans-retinoic acid (ATRA), alone and in combination with arsenic trioxide (ATO), restores differentiation in APL cells and promotes degradation of the abnormal oncogenic fusion protein through several proteolytic mechanisms. RARα fusion-protein elimination is emerging as critical to obtaining sustained remission and long-term cure in APL. Autophagy is a degradative cellular pathway involved in protein turnover. Both ATRA and ATO also induce autophagy in APL cells. Enhancing autophagy may therefore be of therapeutic benefit in resistant APL and could broaden the application of differentiation therapy to other cancers. Here we discuss retinoid signaling in hematopoiesis, leukemogenesis, and APL treatment. We highlight autophagy as a potential important regulator in anti-leukemic strategies. - Highlights: • Normal and aberrant retinoid signaling in hematopoiesis and leukemia is reviewed. • We suggest a novel role for RARα in the development of X-RARα gene fusions in APL. • ATRA therapy in APL activates transcription and promotes onco-protein degradation. • Autophagy may be involved in both onco-protein degradation and differentiation. • Pharmacologic autophagy induction may potentiate ATRA's therapeutic effects.

  9. The role of autophagy in microbial infection and immunity

    Directory of Open Access Journals (Sweden)

    Desai M

    2015-01-01

    Full Text Available Mayura Desai,1 Rong Fang,2 Jiaren Sun11Department of Microbiology and Immunology, 2Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX, USAAbstract: The autophagy pathway represents an evolutionarily conserved cell recycling process that is activated in response to nutrient deprivation and other stress signals. Over the years, it has been linked to an array of cellular functions. Equally, a wide range of cell-intrinsic, as well as extracellular, factors have been implicated in the induction of the autophagy pathway. Microbial infections represent one such factor that can not only activate autophagy through specific mechanisms but also manipulate the response to the invading microbe's advantage. Moreover, in many cases, particularly among viruses, the pathway has been shown to be intricately involved in the replication cycle of the pathogen. Conversely, autophagy also plays a role in combating the infection process, both through direct destruction of the pathogen and as one of the key mediating factors in the host defense mechanisms of innate and adaptive immunity. Further, the pathway also plays a role in controlling the pathogenesis of infectious diseases by regulating inflammation. In this review, we discuss various interactions between pathogens and the cellular autophagic response and summarize the immunological functions of the autophagy pathway.Keywords: autophagy, xenophagy, antiviral, antibacterial

  10. Activation of Autophagy by Metals in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Pérez-Martín, Marta; Blaby-Haas, Crysten E; Pérez-Pérez, María Esther; Andrés-Garrido, Ascensión; Blaby, Ian K; Merchant, Sabeeha S; Crespo, José L

    2015-09-01

    Autophagy is an intracellular self-degradation pathway by which eukaryotic cells recycle their own material in response to specific stress conditions. Exposure to high concentrations of metals causes cell damage, although the effect of metal stress on autophagy has not been explored in photosynthetic organisms. In this study, we investigated the effect of metal excess on autophagy in the model unicellular green alga Chlamydomonas reinhardtii. We show in cells treated with nickel an upregulation of ATG8 that is independent of CRR1, a global regulator of copper signaling in Chlamydomonas. A similar effect on ATG8 was observed with copper and cobalt but not with cadmium or mercury ions. Transcriptome sequencing data revealed an increase in the abundance of the protein degradation machinery, including that responsible for autophagy, and a substantial overlap of that increased abundance with the hydrogen peroxide response in cells treated with nickel ions. Thus, our results indicate that metal stress triggers autophagy in Chlamydomonas and suggest that excess nickel may cause oxidative damage, which in turn activates degradative pathways, including autophagy, to clear impaired components and recover cellular homeostasis. PMID:26163317

  11. Protective Effects of Gastrodin Against Autophagy-Mediated Astrocyte Death.

    Science.gov (United States)

    Wang, Xin-shang; Tian, Zhen; Zhang, Nan; Han, Jing; Guo, Hong-liang; Zhao, Ming-gao; Liu, Shui-bing

    2016-03-01

    Gastrodin is an active ingredient derived from the rhizome of Gastrodia elata. This compound is usually used to treat convulsive illness, dizziness, vertigo, and headache. This study aimed to investigate the effect of gastrodin on the autophagy of glial cells exposed to lipopolysaccharides (LPS, 1 µg/mL). Autophagy is a form of programmed cell death, although it also promotes cell survival. In cultured astrocytes, LPS exposure induced excessive autophagy and apoptosis, which were significantly prevented by the pretreatment cells with gastrodin (10 μM). The protective effects of gastrodin via autophagy inhibition were verified by the decreased levels of LC3-II, P62, and Beclin-1, which are classical markers for autophagy. Furthermore, gastrodin protected astrocytes from apoptosis through Bcl-2 and Bax signaling pathway. The treatment of astrocytes with rapamycin (500 nM), wortmannin (100 nM), and LY294002 (10 μM), which are inhibitors of mTOR and PI3K, respectively, eliminated the known effects of gastrodin on the inhibited Beclin-1 expression. Furthermore, gastrodin blocked the down-regulation of glutamine synthetase induced by LPS exposure in astrocytes. Our results suggest that gastrodin can be used as a preventive agent for the excessive autophagy induced by LPS. PMID:26643508

  12. Adipose tissue fibrosis

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    The increasing prevalence of obesity causes a majorinterest in white adipose tissue biology. Adipose tissuecells are surrounded by extracellular matrix proteinswhose composition and remodeling is of crucial importancefor cell function. The expansion of adipose tissue inobesity is linked to an inappropriate supply with oxygenand hypoxia development. Subsequent activation ofhypoxia inducible factor 1 (HIF-1) inhibits preadipocytedifferentiation and initiates adipose tissue fibrosis. Therebyadipose tissue growth is limited and excess triglyceridesare stored in ectopic tissues. Stressed adipocytes andhypoxia contribute to immune cell immigration andactivation which further aggravates adipose tissuefibrosis. There is substantial evidence that adipose tissuefibrosis is linked to metabolic dysfunction,both in rodentmodels and in the clinical setting. Peroxisome proliferatoractivated receptor gamma agonists and adiponectin bothreduce adipose tissue fibrosis, inflammation and insulinresistance. Current knowledge suggests that antifibroticdrugs, increasing adipose tissue oxygen supply or HIF-1antagonists will improve adipose tissue function andthereby ameliorate metabolic diseases.

  13. Autophagy Promotes Focal Adhesion Disassembly and Cell Motility of Metastatic Tumor Cells through the Direct Interaction of Paxillin with LC3.

    Science.gov (United States)

    Sharifi, Marina N; Mowers, Erin E; Drake, Lauren E; Collier, Chris; Chen, Hong; Zamora, Marta; Mui, Stephanie; Macleod, Kay F

    2016-05-24

    Autophagy is a conserved catabolic process that plays a housekeeping role in eliminating protein aggregates and organelles and is activated during nutrient deprivation to generate metabolites and energy. Autophagy plays a significant role in tumorigenesis, although opposing context-dependent functions of autophagy in cancer have complicated efforts to target autophagy for therapeutic purposes. We demonstrate that autophagy inhibition reduces tumor cell migration and invasion in vitro and attenuates metastasis in vivo. Numerous abnormally large focal adhesions (FAs) accumulate in autophagy-deficient tumor cells, reflecting a role for autophagy in FA disassembly through targeted degradation of paxillin. We demonstrate that paxillin interacts with processed LC3 through a conserved LIR motif in the amino-terminal end of paxillin and that this interaction is regulated by oncogenic SRC activity. Together, these data establish a function for autophagy in FA turnover, tumor cell motility, and metastasis. PMID:27184837

  14. The neuro-glial properties of adipose-derived adult stromal (ADAS cells are not regulated by Notch 1 and are not derived from neural crest lineage.

    Directory of Open Access Journals (Sweden)

    Philip C Wrage

    Full Text Available We investigated whether adipose-derived adult stromal (ADAS are of neural crest origin and the extent to which Notch 1 regulates their growth and differentiation. Mouse ADAS cells cultured in media formulated for neural stem cells (NSC displayed limited capacity for self-renewal, clonogenicity, and neurosphere formation compared to NSC from the subventricular zone in the hippocampus. Although ADAS cells expressed Nestin, GFAP, NSE and Tuj1 in vitro, exposure to NSC differentiation supplements did not induce mature neuronal marker expression. In contrast, in mesenchymal stem cell (MSC media, ADAS cells retained their ability to proliferate and differentiate beyond 20 passages and expressed high levels of Nestin. In neuritizing cocktails, ADAS cells extended processes, downregulated Nestin expression, and displayed depolarization-induced Ca(2+ transients but no spontaneous or evoked neural network activity on Multi-Electrode Arrays. Deletion of Notch 1 in ADAS cell cultures grown in NSC proliferation medium did not significantly alter their proliferative potential in vitro or the differentiation-induced downregulation of Nestin. Co-culture of ADAS cells with fibroblasts that stably expressed the Notch ligand Jagged 1 or overexpression of the Notch intracellular domain (NICD did not alter ADAS cell growth, morphology, or cellular marker expression. ADAS cells did not display robust expression of neural crest transcription factors or genes (Sox, CRABP2, and TH; and lineage tracing analyses using Wnt1-Cre;Rosa26R-lacZ or -EYFP reporter mice confirmed that fewer than 2% of the ADAS cell population derived from a Wnt1-positive population during development. In summary, although media formulations optimized for MSCs or NSCs enable expansion of mouse ADAS cells in vitro, we find no evidence that these cells are of neural crest origin, that they can undergo robust terminal differentiation into functionally mature neurons, and that Notch 1 is likely to be

  15. Differential regulatory functions of three classes of phosphatidylinositol and phosphoinositide 3-kinases in autophagy.

    Science.gov (United States)

    Yu, Xinlei; Long, Yun Chau; Shen, Han-Ming

    2015-01-01

    Autophagy is an evolutionarily conserved and exquisitely regulated self-eating cellular process with important biological functions. Phosphatidylinositol 3-kinases (PtdIns3Ks) and phosphoinositide 3-kinases (PI3Ks) are involved in the autophagic process. Here we aim to recapitulate how 3 classes of these lipid kinases differentially regulate autophagy. Generally, activation of the class I PI3K suppresses autophagy, via the well-established PI3K-AKT-MTOR (mechanistic target of rapamycin) complex 1 (MTORC1) pathway. In contrast, the class III PtdIns3K catalytic subunit PIK3C3/Vps34 forms a protein complex with BECN1 and PIK3R4 and produces phosphatidylinositol 3-phosphate (PtdIns3P), which is required for the initiation and progression of autophagy. The class II enzyme emerged only recently as an alternative source of PtdIns3P and autophagic initiator. However, the orthodox paradigm is challenged by findings that the PIK3CB catalytic subunit of class I PI3K acts as a positive regulator of autophagy, and PIK3C3 was thought to be an amino acid sensor for MTOR, which curbs autophagy. At present, a number of PtdIns3K and PI3K inhibitors, including specific PIK3C3 inhibitors, have been developed for suppression of autophagy and for clinical applications in autophagy-related human diseases.

  16. Genetic versus Non-Genetic Regulation of miR-103, miR-143 and miR-483-3p Expression in Adipose Tissue and Their Metabolic Implications—A Twin Study

    Directory of Open Access Journals (Sweden)

    Jette Bork-Jensen

    2014-07-01

    Full Text Available Murine models suggest that the microRNAs miR-103 and miR-143 may play central roles in the regulation of subcutaneous adipose tissue (SAT and development of type 2 diabetes (T2D. The microRNA miR-483-3p may reduce adipose tissue expandability and cause ectopic lipid accumulation, insulin resistance and T2D. We aimed to explore the genetic and non-genetic factors that regulate these microRNAs in human SAT, and to investigate their impact on metabolism in humans. Levels of miR-103, miR-143 and miR-483-3p were measured in SAT biopsies from 244 elderly monozygotic and dizygotic twins using real-time PCR. Heritability estimates were calculated and multiple regression analyses were performed to study associations between these microRNAs and measures of metabolism, as well as between these microRNAs and possible regulating factors. We found that increased BMI was associated with increased miR-103 expression levels. In addition, the miR-103 levels were positively associated with 2 h plasma glucose levels and hemoglobin A1c independently of BMI. Heritability estimates for all three microRNAs were low. In conclusion, the expression levels of miR-103, miR-143 and miR-483-3p in adipose tissue are primarily influenced by non-genetic factors, and miR-103 may be involved in the development of adiposity and control of glucose metabolism in humans.

  17. Ras-Related Tumorigenesis Is Suppressed by BNIP3-Mediated Autophagy through Inhibition of Cell Proliferation

    Directory of Open Access Journals (Sweden)

    Shan-Ying Wu

    2011-12-01

    Full Text Available Autophagy plays diverse roles in Ras-related tumorigenesis. H-rasval12 induces autophagy through multiple signaling pathways including Raf-1/ERK pathway, and various ERK downstream molecules of autophagy have been reported. In this study, Bcl-2/adenovirus E1B 19-kDa–interacting protein 3 (BNIP3 is identified as a downstream transducer of the Ras/Raf/ERK signaling pathway to induce autophagy. BNIP3 was upregulated by H-rasval12 at the transcriptional level to compete with Beclin 1 for binding with Bcl-2. H-rasval12–induced autophagy suppresses cell proliferation demonstrated both in vitro and in vivo by expression of ectopic BNIP3, Atg5, or interference RNA of BNIP3 (siBNIP3 and Atg5 (shAtg5 using mouse NIH3T3 and embryo fibroblast cells. H-rasval12 induces different autophagic responses depending on the duration of Ras overexpression. After a short time (48 hours of Ras overexpression, autophagy inhibits cell proliferation. In contrast, a longer time (2 weeks of Ras overexpression, cell proliferation was enhanced by autophagy. Furthermore, overexpression of mutant Ras, BNIP3, and LC3-II was detected in bladder cancer T24 cells and the tumor parts of 75% of bladder cancer specimens indicating a positive correlation between autophagy and tumorigenesis. Taken together, our mouse model demonstrates a balance between BNIP3-mediated autophagy and H-rasval12–induced tumor formation and reveals that H-rasval12 induces autophagy in a BNIP3-dependent manner, and the threshold of autophagy plays a decisive role in H-rasval12–induced tumorigenesis. Our findings combined with others’ reports suggest a new therapeutic strategy against Ras-related tumorigenesis by negative or positive regulation of autophagic activity, which is determined by the level of autophagy and tumor progression stages.

  18. The role of autophagy in the intracellular survival of Campylobacter concisus

    Directory of Open Access Journals (Sweden)

    Jose A. Burgos-Portugal

    2014-01-01

    Full Text Available Campylobacter concisus is an emerging pathogen that has been associated with gastrointestinal diseases. Given the importance of autophagy for the elimination of intracellular bacteria and the subversion of this process by pathogenic bacteria, we investigated the role of autophagy in C. concisus intracellular survival. Gentamicin protection assays were employed to assess intracellular levels of C. concisus within Caco-2 cells, following autophagy induction and inhibition. To assess the interaction between C. concisus and autophagosomes, confocal microscopy, scanning electron microscopy, and transmission electron microscopy were employed. Expression levels of 84 genes involved in the autophagy process were measured using qPCR. Autophagy inhibition resulted in two- to four-fold increases in intracellular levels of C. concisus within Caco-2 cells, while autophagy induction resulted in a significant reduction in intracellular levels or bacterial clearance. C. concisus strains with low intracellular survival levels showed a dramatic increase in these levels upon autophagy inhibition. Confocal microscopy showed co-localization of the bacterium with autophagosomes, while transmission electron microscopy identified intracellular bacteria persisting within autophagic vesicles. Further, qPCR showed that following infection, 13 genes involved in the autophagy process were significantly regulated, and a further five showed borderline results, with an overall indication towards a dampening effect exerted by the bacterium on this process. Our data collectively indicates that while autophagy is important for the clearance of C. concisus, some strains may manipulate this process to benefit their intracellular survival.

  19. Death and survival of neuronal and astrocytic cells in ischemic brain injury: a role of autophagy

    Institute of Scientific and Technical Information of China (English)

    Min XU; Hui-ling ZHANG

    2011-01-01

    Autophagy is a highly regulated cellular mechanism that leads to degradation of long-lived proteins and dysfunctional organelles. The process has been implicated in a variety of physiological and pathological conditions relevant to neurological diseases. Recent studies show the existence of autophagy in cerebral ischemia, but no consensus has yet been reached regarding the functions of autophagy in this condition. This article highlights the activation of autophagy during cerebral ischemia and/or reperfusion, especially in neurons and astrocytes, as well as the role of autophagy in neuronal or astrocytic cell death and survival. We propose that physiological levels of autophagy, presumably caused by mild to modest hypoxia or ischemia, appear to be protective. However, high levels of autophagy caused by severe hypoxia or ischemia and/or reperfusion may cause self-digestion and eventual neuronal and astrocytic cell death. We also discuss that oxidative and endoplasmic reticulum (ER) stresses in cerebral hypoxia or ischemia and/or reperfusion are potent stimuli of autophagy in neurons and astrocytes. In addition, we review the evidence suggesting a considerable overlap between autophagy on one hand, and apoptosis, necrosis and necroptosis on the other hand, in determining the outcomes and final morphology of damaged neurons and astrocytes.

  20. Autophagy and ethanol-induced liver injury

    Institute of Scientific and Technical Information of China (English)

    Terrence M Donohue Jr

    2009-01-01

    The majority of ethanol metabolism occurs in the liver. Consequently, this organ sustains the greatest damage from ethanol abuse. Ethanol consumption disturbs the delicate balance of protein homeostasis in the liver, causing intracellular protein accumulation due to a disruption of hepatic protein catabolism.Evidence indicates that ethanol or its metabolism impairs trafficking events in the liver, including the process of macroautophagy, which is the engulfment and degradation of cytoplasmic constituents by the lysosomal system. Autophagy is an essential, ongoing cellular process that is highly regulated by nutrients,endocrine factors and signaling pathways. A great number of the genes and gene products that govern the autophagic response have been characterized and the major metabolic and signaling pathways that activate or suppress autophagy have been identified. This review describes the process of autophagy, its regulation and the possible mechanisms by which ethanol disrupts the process of autophagic degradation. The implications of autophagic suppression are discussed in relation to the pathogenesis of alcohol-induced liver injury.

  1. Adipose tissue: cell heterogeneity and functional diversity.

    Science.gov (United States)

    Esteve Ràfols, Montserrat

    2014-02-01

    There are two types of adipose tissue in the body whose function appears to be clearly differentiated. White adipose tissue stores energy reserves as fat, whereas the metabolic function of brown adipose tissue is lipid oxidation to produce heat. A good balance between them is important to maintain energy homeostasis. The concept of white adipose tissue has radically changed in the past decades, and is now considered as an endocrine organ that secretes many factors with autocrine, paracrine, and endocrine functions. In addition, we can no longer consider white adipose tissue as a single tissue, because it shows different metabolic profiles in its different locations, with also different implications. Although the characteristic cell of adipose tissue is the adipocyte, this is not the only cell type present in adipose tissue, neither the most abundant. Other cell types in adipose tissue described include stem cells, preadipocytes, macrophages, neutrophils, lymphocytes, and endothelial cells. The balance between these different cell types and their expression profile is closely related to maintenance of energy homeostasis. Increases in adipocyte size, number and type of lymphocytes, and infiltrated macrophages are closely related to the metabolic syndrome diseases. The study of regulation of proliferation and differentiation of preadipocytes and stem cells, and understanding of the interrelationship between the different cell types will provide new targets for action against these diseases.

  2. Secretory function of adipose tissue.

    Science.gov (United States)

    Kuryszko, J; Sławuta, P; Sapikowski, G

    2016-01-01

    There are two kinds of adipose tissue in mammals: white adipose tissue - WAT and brown adipose tissue - BAT. The main function of WAT is accumulation of triacylglycerols whereas the function of BAT is heat generation. At present, WAT is also considered to be an endocrine gland that produces bioactive adipokines, which take part in glucose and lipid metabolism. Considering its endocrine function, the adipose tissue is not a homogeneous gland but a group of a few glands which act differently. Studies on the secretory function of WAT began in 1994 after discovery of leptin known as the satiation hormone, which regulates body energy homeostasis and maintainence of body mass. Apart from leptin, the following belong to adipokines: adiponectin, resistin, apelin, visfatin and cytokines: TNF and IL 6. Adiponectin is a polypeptide hormone of antidiabetic, anti-inflammatory and anti-atherogenic activity. It plays a key role in carbohydrate and fat metabolism. Resistin exerts a counter effect compared to adiponectin and its physiological role is to maintain fasting glycaemia. Visfatin stimulates insulin secretion and increases insulin sensitivity and glucose uptake by muscle cells and adipocytes. Apelin probably increases the insulin sensitivity of tissues. TNF evokes insulin resistance by blocking insulin receptors and inhibits insulin secretion. Approximately 30% of circulating IL 6 comes from adipose tissue. It causes insulin resistance by decreasing the expression of insulin receptors, decreases adipogenesis and adiponectin and visfatin secretion, and stimulates hepatic gluconeogenesis. In 2004, Bays introduced the notion of adiposopathy, defined as dysfunction of the adipose tissue, whose main feature is insulin and leptin resistance as well as the production of inflammatory cytokines: TNF and IL 6 and monocyte chemoattractant protein. This means that excess of adipose tissue, especially visceral adipose tissue, leads to the development of a chronic subclinical

  3. Adipose, bone and muscle tissues as new endocrine organs: role of reciprocal regulation for osteoporosis and obesity development.

    Science.gov (United States)

    Migliaccio, Silvia; Greco, Emanuela A; Wannenes, Francesca; Donini, Lorenzo M; Lenzi, Andrea

    2014-01-01

    The belief that obesity is protective against osteoporosis has recently been revised. In fact, the latest epidemiologic and clinical studies show that a high level of fat mass, but also reduced muscle mass, might be a risk factor for osteoporosis and fragility fractures. Furthermore, increasing evidence seems to indicate that different components such as myokines, adipokines and growth factors, released by both fat and muscle tissues, could play a key role in the regulation of skeletal health and in low bone mineral density and, thus, in osteoporosis development. This review considers old and recent data in the literature to further evaluate the relationship between fat, bone and muscle tissue.

  4. Autophagy in cardiovascular biology

    OpenAIRE

    Lavandero, Sergio; Chiong, Mario; Rothermel, Beverly A.; Hill, Joseph A.

    2015-01-01

    Cardiovascular disease is the leading cause of death worldwide. As such, there is great interest in identifying novel mechanisms that govern the cardiovascular response to disease-related stress. First described in failing hearts, autophagy within the cardiovascular system has been widely characterized in cardiomyocytes, cardiac fibroblasts, endothelial cells, vascular smooth muscle cells, and macrophages. In all cases, a window of optimal autophagic activity appears to be critical to the mai...

  5. AUTOPHAGY IN LUNG CANCER

    OpenAIRE

    Jaboin, Jerry J.; Hwang, Misun; Lu, Bo

    2009-01-01

    Lung cancer is the leading cause of cancer-related deaths worldwide. The relatively poor cure rate in lung cancer patients has been associated with a resistance to chemotherapy and radiation that is at least in part related to defects in cellular apoptotic machinery. Exploitation of another form of cell death, autophagy, has the capacity to improve the therapeutic gain of current therapies. In an effort to develop novel treatment strategies to enhance the therapeutic ratio for lung cancer, we...

  6. Autophagy in dementias.

    Science.gov (United States)

    Kragh, Christine Lund; Ubhi, Kiren; Wyss-Coray, Tony; Wyss-Corey, Tony; Masliah, Eliezer

    2012-01-01

    Dementias are a varied group of disorders typically associated with memory loss, impaired judgment and/or language and by symptoms affecting other cognitive and social abilities to a degree that interferes with daily functioning. Alzheimer's disease (AD) is the most common cause of a progressive dementia, followed by dementia with Lewy bodies (DLB), frontotemporal dementia (FTD), (VaD) and HIV-associated neurocognitive disorders (HAND). The pathogenesis of this group of disorders has been linked to the abnormal accumulation of proteins in the brains of affected individuals, which in turn has been related to deficits in protein clearance. Autophagy is a key cellular protein clearance pathway with proteolytic cleavage and degradation via the ubiquitin-proteasome pathway representing another important clearance mechanism. Alterations in the levels of autophagy and the proteins associated with the autophagocytic pathway have been reported in various types of dementias. This review will examine recent literature across these disorders and highlight a common theme of altered autophagy across the spectrum of the dementias. PMID:22150925

  7. Roles of autophagy in male reproductive development in plants

    Directory of Open Access Journals (Sweden)

    Shigeru eHanamata

    2014-09-01

    Full Text Available Autophagy, a major catabolic pathway in eukaryotic cells, is essential in development, maintenance of cellular homeostasis, immunity and programmed cell death (PCD in multicellular organisms. In plant cells, autophagy plays roles in recycling of proteins and metabolites including lipids, and is involved in many physiological processes such as abiotic and biotic stress responses. However, its roles during reproductive development had remained poorly understood. Quantitative live cell imaging techniques for the autophagic flux and genetic studies in several plant species have recently revealed significant roles of autophagy in developmental processes, regulation of PCD and lipid metabolism. We here review the novel roles of autophagic fluxes in plant cells, and discuss their possible significance in PCD and metabolic regulation, with particular focus on male reproductive development during the pollen maturation.

  8. 4-Hydroxynonenal Regulates TNF-α Gene Transcription Indirectly via ETS1 and microRNA-29b in Human Adipocytes Induced From Adipose Tissue-Derived Stromal Cells.

    Science.gov (United States)

    Zhang, Xi-Mei; Guo, Lin; Huang, Xiang; Li, Qiu-Ming; Chi, Mei-Hua

    2016-08-01

    Obesity is characterized by an accumulation of excessive body fat and can be diagnosed by a variety of measures, such as BMI. However, in some obese individuals, oxidative stress is also thought to be an important pathogenic mechanism of obesity-associated metabolic syndrome. Oxidative stress increases the lipid peroxidation product, 4-hydroxynonenal (4-HNE), which is one of the most abundant and active lipid peroxides. Within the adipose tissue, adipocytes are derived from adipose tissue-derived stromal cells (ADSCs), which play a key role in the generation and metabolism of adipose tissue. Additionally, obesity is associated with low-grade inflammation. Specific microRNAs (miRNAs) that regulate obesity-associated inflammation are largely dysregulated in metabolic syndrome (MS). In this study, we aim to confirm whether 4-HNE and miRNAs play a role in the regulation of TNF-α gene transcription. We enrolled six obese individuals who were referred to Harbin Medical University (Heilongjiang, China) and six nonobese control participants. Plasma 4-HNE levels of the 12 subjects were determined by ELISA. Using qRT-PCR, we measured ETS1, miR-29b, SP1, and TNF-α levels in subcutaneous white adipose tissue (WAT). Furthermore, we examined the relationship between ETS1 and TNF-α using a luciferase reporter assay and a ChIP assay. Our results suggest that ETS1 promotes TNF-α gene transcription in adipocytes. In addition, we demonstrated that 4-HNE promotes TNF-α gene transcription through the inhibition of the miR-29b → SP1 → TNF-α pathway and promotion of the ETS1 → TNF-α pathway. Anat Rec, 299:1145-1152, 2016. © 2016 Wiley Periodicals, Inc. PMID:27164408

  9. Regulatory coordination between two major intracellular homeostatic systems: heat shock response and autophagy.

    Science.gov (United States)

    Dokladny, Karol; Zuhl, Micah Nathaniel; Mandell, Michael; Bhattacharya, Dhruva; Schneider, Suzanne; Deretic, Vojo; Moseley, Pope Lloyd

    2013-05-24

    The eukaryotic cell depends on multitiered homeostatic systems ensuring maintenance of proteostasis, organellar integrity, function and turnover, and overall cellular viability. At the two opposite ends of the homeostatic system spectrum are heat shock response and autophagy. Here, we tested whether there are interactions between these homeostatic systems, one universally operational in all prokaryotic and eukaryotic cells, and the other one (autophagy) is limited to eukaryotes. We found that heat shock response regulates autophagy. The interaction between the two systems was demonstrated by testing the role of HSF-1, the central regulator of heat shock gene expression. Knockdown of HSF-1 increased the LC3 lipidation associated with formation of autophagosomal organelles, whereas depletion of HSF-1 potentiated both starvation- and rapamycin-induced autophagy. HSP70 expression but not expression of its ATPase mutant inhibited starvation or rapamycin-induced autophagy. We also show that exercise induces autophagy in humans. As predicted by our in vitro studies, glutamine supplementation as a conditioning stimulus prior to exercise significantly increased HSP70 protein expression and prevented the expected exercise induction of autophagy. Our data demonstrate for the first time that heat shock response, from the top of its regulatory cascade (HSF-1) down to the execution stages delivered by HSP70, controls autophagy thus connecting and coordinating the two extreme ends of the homeostatic systems in the eukaryotic cell. PMID:23576438

  10. Epigallocatechin-3-gallate (EGCG, a green tea polyphenol, stimulates hepatic autophagy and lipid clearance.

    Directory of Open Access Journals (Sweden)

    Jin Zhou

    Full Text Available Epigallocatechin gallate (EGCG is a major polyphenol in green tea that has been shown to have anti-inflammatory, anti-cancer, anti-steatotic effects on the liver. Autophagy also mediates similar effects; however, it is not currently known whether EGCG can regulate hepatic autophagy. Here, we show that EGCG increases hepatic autophagy by promoting the formation of autophagosomes, increasing lysosomal acidification, and stimulating autophagic flux in hepatic cells and in vivo. EGCG also increases phosphorylation of AMPK, one of the major regulators of autophagy. Importantly, siRNA knockdown of AMPK abrogated autophagy induced by EGCG. Interestingly, we observed lipid droplet within autophagosomes and autolysosomes and increased lipid clearance by EGCG, suggesting it promotes lipid metabolism by increasing autophagy. In mice fed with high-fat/western style diet (HFW; 60% energy as fat, reduced levels of calcium, vitamin D3, choline, folate, and fiber, EGCG treatment reduces hepatosteatosis and concomitantly increases autophagy. In summary, we have used genetic and pharmacological approaches to demonstrate EGCG induction of hepatic autophagy, and this may contribute to its beneficial effects in reducing hepatosteatosis and potentially some other pathological liver conditions.

  11. Genetic mutations in adipose triglyceride lipase and myocardial up-regulation of peroxisome proliferated activated receptor-γ in patients with triglyceride deposit cardiomyovasculopathy

    International Nuclear Information System (INIS)

    Highlights: •Triglyceride deposit cardiomyovasculopathy (TGCV) is a rare severe heart disease. •PPARγ is up-regulated in myocardium in patients with TGCV. •Possible vicious cycle for fatty acid may be involved in pathophysiology of TGCV. -- Abstract: Adipose triglyceride lipase (ATGL, also known as PNPLA2) is an essential molecule for hydrolysis of intracellular triglyceride (TG). Genetic ATGL deficiency is a rare multi-systemic neutral lipid storage disease. Information regarding its clinical profile and pathophysiology, particularly for cardiac involvement, is still very limited. A previous middle-aged ATGL-deficient patient in our institute (Case 1) with severe heart failure required cardiac transplantation (CTx) and exhibited a novel phenotype, “Triglyceride deposit cardiomyovasculopathy (TGCV)”. Here, we tried to elucidate molecular mechanism underlying TGCV. The subjects were two cases with TGCV, including our second case who was a 33-year-old male patient (Case 2) with congestive heart failure requiring CTx. Case 2 was homozygous for a point mutation in the 5′ splice donor site of intron 5 in the ATGL, which results in at least two types of mRNAs due to splicing defects. The myocardium of both patients (Cases 1 and 2) showed up-regulation of peroxisome proliferated activated receptors (PPARs), key transcription factors for metabolism of long chain fatty acids (LCFAs), which was in contrast to these molecules’ lower expression in ATGL-targeted mice. We investigated the intracellular metabolism of LCFAs under human ATGL-deficient conditions using patients’ passaged skin fibroblasts as a model. ATGL-deficient cells showed higher uptake and abnormal intracellular transport of LCFA, resulting in massive TG accumulation. We used these findings from cardiac specimens and cell-biological experiments to construct a hypothetical model to clarify the pathophysiology of the human disorder. In patients with TGCV, even when hydrolysis of intracellular TG

  12. Genetic mutations in adipose triglyceride lipase and myocardial up-regulation of peroxisome proliferated activated receptor-γ in patients with triglyceride deposit cardiomyovasculopathy

    Energy Technology Data Exchange (ETDEWEB)

    Hirano, Ken-ichi, E-mail: khirano@cnt-osaka.com [Laboratory of Cardiovascular Disease, Novel, Non-Invasive, and Nutritional Therapeutics (CNT), Graduate School of Medicine, Osaka University, 6-2-3, Furuedai, Suita, Osaka 565-0874 (Japan); Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, 2-2, Yamadaoka, Suita, Osaka 565-0871 (Japan); Tanaka, Tatsuya [Center for Medical Research and Education, Graduate School of Medicine, Osaka University, 2-2, Yamadaoka, Suita, Osaka 565-0871 (Japan); Ikeda, Yoshihiko [Department of Pathology, National Cerebral and Cardiovascular Center, 5-7-1 Fujishirodai, Suita 565-8565 (Japan); Yamaguchi, Satoshi [Laboratory of Cardiovascular Disease, Novel, Non-Invasive, and Nutritional Therapeutics (CNT), Graduate School of Medicine, Osaka University, 6-2-3, Furuedai, Suita, Osaka 565-0874 (Japan); Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, 2-2, Yamadaoka, Suita, Osaka 565-0871 (Japan); Zaima, Nobuhiro [Department of Applied Biochemistry, Kinki University, 3327-204, Nakamachi, Nara 631-8505 (Japan); Kobayashi, Kazuhiro [Division of Neurology/Molecular Brain Science, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Suzuki, Akira [Laboratory of Cardiovascular Disease, Novel, Non-Invasive, and Nutritional Therapeutics (CNT), Graduate School of Medicine, Osaka University, 6-2-3, Furuedai, Suita, Osaka 565-0874 (Japan); Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, 2-2, Yamadaoka, Suita, Osaka 565-0871 (Japan); Sakata, Yasuhiko [Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, 2-2, Yamadaoka, Suita, Osaka 565-0871 (Japan); Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, 1-1, Seiryo-cho, Aoba-ku, Sendai 980-8574 (Japan); and others

    2014-01-10

    Highlights: •Triglyceride deposit cardiomyovasculopathy (TGCV) is a rare severe heart disease. •PPARγ is up-regulated in myocardium in patients with TGCV. •Possible vicious cycle for fatty acid may be involved in pathophysiology of TGCV. -- Abstract: Adipose triglyceride lipase (ATGL, also known as PNPLA2) is an essential molecule for hydrolysis of intracellular triglyceride (TG). Genetic ATGL deficiency is a rare multi-systemic neutral lipid storage disease. Information regarding its clinical profile and pathophysiology, particularly for cardiac involvement, is still very limited. A previous middle-aged ATGL-deficient patient in our institute (Case 1) with severe heart failure required cardiac transplantation (CTx) and exhibited a novel phenotype, “Triglyceride deposit cardiomyovasculopathy (TGCV)”. Here, we tried to elucidate molecular mechanism underlying TGCV. The subjects were two cases with TGCV, including our second case who was a 33-year-old male patient (Case 2) with congestive heart failure requiring CTx. Case 2 was homozygous for a point mutation in the 5′ splice donor site of intron 5 in the ATGL, which results in at least two types of mRNAs due to splicing defects. The myocardium of both patients (Cases 1 and 2) showed up-regulation of peroxisome proliferated activated receptors (PPARs), key transcription factors for metabolism of long chain fatty acids (LCFAs), which was in contrast to these molecules’ lower expression in ATGL-targeted mice. We investigated the intracellular metabolism of LCFAs under human ATGL-deficient conditions using patients’ passaged skin fibroblasts as a model. ATGL-deficient cells showed higher uptake and abnormal intracellular transport of LCFA, resulting in massive TG accumulation. We used these findings from cardiac specimens and cell-biological experiments to construct a hypothetical model to clarify the pathophysiology of the human disorder. In patients with TGCV, even when hydrolysis of intracellular TG

  13. PGC-1α is required for exercise- and exercise training-induced UCP1 up-regulation in mouse white adipose tissue.

    Directory of Open Access Journals (Sweden)

    Stine Ringholm

    Full Text Available BACKGROUND: The aim of the present study was to test the hypotheses that 1 a single exercise bout increases UCP1 mRNA in both inguinal (iWAT and epididymal (eWAT, 2 UCP1 expression and responsiveness to exercise are different in iWAT and eWAT, 3 PGC-1α determines the basal levels of UCP1 and PRDM16 in WAT and 4 exercise and exercise training regulate UCP1 and PRDM16 expression in WAT in a PGC-1α-dependent manner. METHODS: Whole body PGC-1α knockout (KO and wildtype (WT littermate mice performed a single treadmill exercise bout at 14 m/min and 10% slope for 1 hour. Mice were sacrificed and iWAT, eWAT and quadriceps muscle were removed immediately after, 2, 6 and 10 hours after running, and from sedentary mice that served as controls. In addition, PGC-1α KO mice and WT littermates were exercise trained for 5 weeks with sedentary mice as untrained controls. Thirty-six-37 hours after the last exercise bout iWAT was removed. RESULTS: UCP1 mRNA content increased 19-fold in iWAT and 7.5-fold in eWAT peaking at 6 h and 0' of recovery, respectively, in WT but with no changes in PGC-1α KO mice. UCP1 protein was undetectable in eWAT and very low in iWAT of untrained mice but increased with exercise training to 4.4 (AU in iWAT from WT mice without significant effects in PGC-1α KO mice. CONCLUSION: The present observations provide evidence that exercise training increases UCP1 protein in iWAT through PGC-1α, likely as a cumulative effect of transient increases in UCP1 expression after each exercise bout. Moreover, the results suggest that iWAT is more responsive than eWAT in exercise-induced regulation of UCP1. In addition, as PRDM16 mRNA content decreased in recovery from acute exercise, the present findings suggest that acute exercise elicits regulation of several brown adipose tissue genes in mouse WAT.

  14. Hexokinase II inhibitor, 3-BrPA induced autophagy by stimulating ROS formation in human breast cancer cells

    OpenAIRE

    Zhang, Qianwen; Zhang, Yuanyuan; Zhang, Pei; Chao, Zhenhua; Xia, Fei; Jiang, Chenchen; Zhang, Xudong; JIANG, ZHIWEN; Liu, Hao

    2014-01-01

    Hexokinase II (HKII), a key enzyme of glycolysis, is widely over-expressed in cancer cells. 3-bromopyruvate (3-BrPA), an inhibitor of HK II, has been proposed as a specific antitumor agent. Autophagy is a process that regulates the balance between protein synthesis and protein degradation. Autophagy in mammalian systems occurs under basal conditions and can be stimulated by stresses, including starvation, oxidative stress. Therefore, we hypothesized that 3-BrPA could induce autophagy. In the ...

  15. Impact of embryo number and periconceptional undernutrition on factors regulating adipogenesis, lipogenesis, and metabolism in adipose tissue in the sheep fetus.

    Science.gov (United States)

    Lie, Shervi; Morrison, Janna L; Williams-Wyss, Olivia; Ozanne, Susan E; Zhang, Song; Walker, Simon K; Kleemann, David O; MacLaughlin, Severence M; Roberts, Claire T; McMillen, I Caroline

    2013-10-15

    Maternal undernutrition around the time of conception is associated with an increased risk of insulin resistance in adulthood. We hypothesized that maternal undernutrition during the periconceptional (PCUN: -60 to 7 days) and/or preimplantation (PIUN: 0-7 days) periods would result in a decrease in UCP1 expression and the abundance of insulin signaling molecules and an increase in the abundance of factors that regulate adipogenesis and lipogenesis in fetal perirenal adipose tissue (PAT) and that these effects would be different in singletons and twins. Maternal PCUN and PIUN resulted in a decrease in UCP1 expression in PAT, and PIUN resulted in higher circulating insulin concentrations, an increased abundance of pPKCζ and PDK4, and a decreased abundance of Akt1, phosphorylated mTOR, and PPARγ in PAT in singleton and twin fetuses. In singletons, there was also a decrease in the abundance of p110β in PAT in the PCUN and PIUN groups and an increase in total AMPKα in PAT in the PIUN group. In twins, however, there was an increase in the abundance of mTOR in the PCUN group and an increase in PDK2 and decrease in total AMPKα in the PIUN group. Thus exposure to periconceptional undernutrition programs changes in the thermogenic capacity and the insulin and fatty acid oxidation signaling pathway in visceral fat, and these effects are different in singletons and twins. These findings are important, as the thermogenic capacity of brown fat and the insulin sensitivity of visceral fat are important determinants of the risk of developing obesity and an insulin resistance phenotype in later life. PMID:23921136

  16. Regulation of apelin and its receptor expression in adipose tissues of obesity rats with hypertension and cultured 3T3-L1 adipocytes.

    Science.gov (United States)

    Wu, Hongxian; Cheng, Xian Wu; Hao, Changning; Zhang, Zhi; Yao, Huali; Murohara, Toyoaki; Dai, Qiuyan

    2014-01-01

    The apelin/APJ system has been implicated in obesity-related hypertension. We investigated the mechanism responsible for the pathogenesis of obesity-related hypertension with a special focus on the crosstalk between AngII/its type 1 receptor (AT1R) signaling and apelin/APJ expression. Sprague-Dawley rats fed a high-fat (obesity-related hypertension, OH) or normal-fat diet (NF) for 15 weeks were randomly assigned to one of two groups and administered vehicle or perindopril for 4 weeks. Compared to the NF rats, the OH rats showed lower levels of plasma apelin and apelin/APJ mRNAs of perirenal adipose tissues, and these changes were restored by perindopril. Administration of the AT1R antagonist olmesartan resulted in the restoration of the reduction of apelin and APJ expressions induced by AngII for 48 h in 3T3-L1 adipocytes. Among several inhibitors for extracellular signal-regulated kinases 1/2 (ERK1/2) PD98059, p38 mitogen-activated protein kinase (p38MAPK) SB203580 and phosphatidylinositol 3-kinase (PI3K) LY294002, the latter showed an additive effect on AngII-mediated inhibitory effects. In addition, the levels of p-Akt, p-ERK and p38MAPK proteins were decreased by long-term treatment with AngII (120 min), and these changes were restored by Olmesartan. Apelin/APJ appears to be impaired in obesity-related hypertension. The AngII inhibition-mediated beneficial effects are likely attributable, at least in part, to restoration of p38/ERK-dependent apelin/APJ expression in diet-induced obesity-related hypertension.

  17. Autophagy and Non-Alcoholic Fatty Liver Disease

    Directory of Open Access Journals (Sweden)

    Vanessa J. Lavallard

    2014-01-01

    Full Text Available Autophagy, or cellular self-digestion, is a catabolic process that targets cell constituents including damaged organelles, unfolded proteins, and intracellular pathogens to lysosomes for degradation. Autophagy is crucial for development, differentiation, survival, and homeostasis. Important links between the regulation of autophagy and liver complications associated with obesity, non-alcoholic fatty liver disease (NAFLD, have been reported. The spectrum of these hepatic abnormalities extends from isolated steatosis to non-alcoholic steatohepatitis (NASH, steatofibrosis, which sometimes leads to cirrhosis, and hepatocellular carcinoma. NAFLD is one of the three main causes of cirrhosis and increases the risk of liver-related death and hepatocellular carcinoma. The pathophysiological mechanisms of the progression of a normal liver to steatosis and then more severe disease are complex and still unclear. The regulation of the autophagic flux, a dynamic response, and the knowledge of the role of autophagy in specific cells including hepatocytes, hepatic stellate cells, immune cells, and hepatic cancer cells have been extensively studied these last years. This review will provide insight into the current understanding of autophagy and its role in the evolution of the hepatic complications associated with obesity, from steatosis to hepatocellular carcinoma.

  18. Ubiquitin and Autophagy%泛素与自噬

    Institute of Scientific and Technical Information of China (English)

    冯梅; 王莉新; 王易

    2011-01-01

    Protein degradation mediated by ubiquitin and autophagy are the basic mechanisms involved in cellular self-regulation. Ubiquitin may be involved in the process of autophagy by serving as a umversal recognition signal. Induction of autophagy can promote ubiquitination, thereby enhancing the degradation of substrate. This paper mainly focuses on the relation and the potential mutual regulation between ubiquitination and autophagy, as well as the phenomenon of programmed cell death that is associated with both ubiquitination and autophagy processes.%泛素调节的蛋白质降解过程和细胞的自噬现象都是细胞自我调节的基本机制.其中,泛素可能作为一种普遍的识别信号参与了自噬过程;而自噬的诱导又能促进泛素化作用,从而增强对底物的降解.本文着重探讨这两者间的关系及可能存在的相互调节作用,并兼及两者共同涉及的细胞程序性死亡现象.

  19. Thyroid hormone stimulates hepatic lipid catabolism via activation of autophagy.

    Science.gov (United States)

    Sinha, Rohit Anthony; You, Seo-Hee; Zhou, Jin; Siddique, Mobin M; Bay, Boon-Huat; Zhu, Xuguang; Privalsky, Martin L; Cheng, Sheue-Yann; Stevens, Robert D; Summers, Scott A; Newgard, Christopher B; Lazar, Mitchell A; Yen, Paul M

    2012-07-01

    For more than a century, thyroid hormones (THs) have been known to exert powerful catabolic effects, leading to weight loss. Although much has been learned about the molecular mechanisms used by TH receptors (TRs) to regulate gene expression, little is known about the mechanisms by which THs increase oxidative metabolism. Here, we report that TH stimulation of fatty acid β-oxidation is coupled with induction of hepatic autophagy to deliver fatty acids to mitochondria in cell culture and in vivo. Furthermore, blockade of autophagy by autophagy-related 5 (ATG5) siRNA markedly decreased TH-mediated fatty acid β-oxidation in cell culture and in vivo. Consistent with this model, autophagy was altered in livers of mice expressing a mutant TR that causes resistance to the actions of TH as well as in mice with mutant nuclear receptor corepressor (NCoR). These results demonstrate that THs can regulate lipid homeostasis via autophagy and help to explain how THs increase oxidative metabolism.

  20. Sex dimorphism and depot differences in adipose tissue function.

    Science.gov (United States)

    White, Ursula A; Tchoukalova, Yourka D

    2014-03-01

    Obesity, characterized by excessive adiposity, is a risk factor for many metabolic pathologies, such as type 2 diabetes mellitus (T2DM). Numerous studies have shown that adipose tissue distribution may be a greater predictor of metabolic health. Upper-body fat (visceral and subcutaneous abdominal) is commonly associated with the unfavorable complications of obesity, while lower-body fat (gluteal-femoral) may be protective. Current research investigations are focused on analyzing the metabolic properties of adipose tissue, in order to better understand the mechanisms that regulate fat distribution in both men and women. This review will highlight the adipose tissue depot- and sex-dependent differences in white adipose tissue function, including adipogenesis, adipose tissue developmental patterning, the storage and release of fatty acids, and secretory function. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease.

  1. Inhibition of autophagy induced by proteasome inhibition increases cell death in human SHG-44 glioma cells

    Institute of Scientific and Technical Information of China (English)

    Peng-fei GE; Ji-zhou ZHANG; Xiao-fei WANG; Fan-kai MENG; Wen-chen LI; Yong-xin LUAN; Feng LING; Yi-nan LUO

    2009-01-01

    Aim:The ubiquitin-proteasome system (UPS) and lysosome-dependent macroautophagy (autophagy) are two major intracellular pathways for protein degradation.Recent studies suggest that proteasome inhibitors may reduce tumor growth and activate autophagy.Due to the dual roles of autophagy in tumor cell survival and death,the effect of autophagy on the destiny of glioma cells remains unclear.In this study,we sought to investigate whether inhibition of the proteasome can induce autophagy and the effects of autophagy on the fate of human SHG-44 glioma cells.Methods:The proteasome inhibitor MG-132 was used to induce autophagy in SHG-44 glioma cells,and the effect of autophagy on the survival of SHG-44 glioma cells was investigated using an autophagy inhibitor 3-MA.Cell viability was measured by MTT assay.Apoptosis and cell cycle were detected by flow cytometry.The expression of autophagy related proteins was determined by Western blot.Results:MG-132 inhibited cell proliferation,induced cell death and cell cycle arrest at G~JM phase,and activated autophagy in SHG-44 glioma cells.The expression of autophagy-related Beclin-1 and LC3-1 was significantly up-regulated and part of LC3-1 was converted into LC3-11.However,when SHG-44 glioma cells were co-treated with MG-132 and 3-MA,the cells became less viable,but cell death and cell numbers at G2/M phase increased.Moreover,the accumulation of acidic vesicular organelles was decreased,the expression of Beclin-1 and LC3 was significantly down-regulated and the conversion of LC3-11 from LC3-1 was also inhibited.Conclusion:Inhibition of the proteasome can induce autophagy in human SHG-44 glioma cells,and inhibition of autophagy increases cell death.This discovery may shed new light on the effect of autophagy on modulating the fate of SHG-44 glioma cells.

  2. Quercetin Alleviates High-Fat Diet-Induced Oxidized Low-Density Lipoprotein Accumulation in the Liver: Implication for Autophagy Regulation

    Directory of Open Access Journals (Sweden)

    Liang Liu

    2015-01-01

    Full Text Available A growing body of evidence has indicated that high-fat diet-induced nonalcoholic fatty liver disease is usually accompanied by oxidized low-density lipoprotein (ox-LDL deposited in the liver. The current study aimed to investigate the effect of quercetin on high-fat diet-induced ox-LDL accumulation in the liver and to explore the potential underlying mechanisms. The results demonstrate that quercetin supplementation for 24 weeks significantly alleviated high-fat diet-induced liver damage and reduced hepatic cholesterol and ox-LDL level. Quercetin notably inhibited both mRNA and protein expression of CD36 (reduced by 53% and 71%, resp. and MSR1 (reduced by 25% and 45%, resp., which were upregulated by high-fat diet. The expression of LC3II was upregulated by 2.4 times whereas that of p62 and mTOR was downregulated by 57% and 63% by quercetin treatment. Therefore, the significantly improved autophagy lysosomal degradation capacity for ox-LDL may be implicated in the hepatoprotective effect of quercetin; scavenger receptors mediated ox-LDL uptake might also be involved.

  3. Neuronal autophagy in cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    Feng Xu; Jin-Hua Gu; Zheng-Hong Qin

    2012-01-01

    Autophagy has evolved as a conserved process for the bulk degradation and recycling of cytosolic components,such as long-lived proteins and organelles.In neurons,autophagy is important for homeostasis and protein quality control and is maintained at relatively low levels under normal conditions,while it is upregulated in response to pathophysiological conditions,such as cerebral ischemic injury.However,the role of autophagy is more complex.It depends on age or brain maturity,region,severity of insult,and the stage of ischemia.Whether autophagy plays a beneficial or a detrimental role in cerebral ischemia depends on various pathological conditions.In this review,we elucidate the role of neuronal autophagy in cerebral ischemia.

  4. Advanced Glycation End Products Affect Osteoblast Proliferation and Function by Modulating Autophagy Via the Receptor of Advanced Glycation End Products/Raf Protein/Mitogen-activated Protein Kinase/Extracellular Signal-regulated Kinase Kinase/Extracellular Signal-regulated Kinase (RAGE/Raf/MEK/ERK) Pathway.

    Science.gov (United States)

    Meng, Hong-Zheng; Zhang, Wei-Lin; Liu, Fei; Yang, Mao-Wei

    2015-11-20

    The interaction between advanced glycation end products (AGEs) and receptor of AGEs (RAGE) is associated with the development and progression of diabetes-associated osteoporosis, but the mechanisms involved are still poorly understood. In this study, we found that AGE-modified bovine serum albumin (AGE-BSA) induced a biphasic effect on the viability of hFOB1.19 cells; cell proliferation was stimulated after exposure to low dose AGE-BSA, but cell apoptosis was stimulated after exposure to high dose AGE-BSA. The low dose AGE-BSA facilitates proliferation of hFOB1.19 cells by concomitantly promoting autophagy, RAGE production, and the Raf/MEK/ERK signaling pathway activation. Furthermore, we investigated the effects of AGE-BSA on the function of hFOB1.19 cells. Interestingly, the results suggest that the short term effects of low dose AGE-BSA increase osteogenic function and decrease osteoclastogenic function, which are likely mediated by autophagy and the RAGE/Raf/MEK/ERK signal pathway. In contrast, with increased treatment time, the opposite effects were observed. Collectively, AGE-BSA had a biphasic effect on the viability of hFOB1.19 cells in vitro, which was determined by the concentration of AGE-BSA and treatment time. A low concentration of AGE-BSA activated the Raf/MEK/ERK signal pathway through the interaction with RAGE, induced autophagy, and regulated the proliferation and function of hFOB1.19 cells.

  5. MYBL2 guides autophagy suppressor VDAC2 in the developing ovary to inhibit autophagy through a complex of VDAC2-BECN1-BCL2L1 in mammals.

    Science.gov (United States)

    Yuan, Jia; Zhang, Ying; Sheng, Yue; Fu, Xiazhou; Cheng, Hanhua; Zhou, Rongjia

    2015-01-01

    Oogenesis is essential for female gamete production in mammals. The total number of ovarian follicles is determined early in life and production of ovarian oocytes is thought to stop during the lifetime. However, the molecular mechanisms underling oogenesis, particularly autophagy regulation in the ovary, remain largely unknown. Here, we reveal an important MYBL2-VDAC2-BECN1-BCL2L1 pathway linking autophagy suppression in the developing ovary. The transcription factors GATA1 and MYBL2 can bind to and activate the Vdac2 promoter. MYBL2 regulates the spatiotemporal expression of VDAC2 in the developing ovary. Strikingly, in the VDAC2 transgenic pigs (Sus scrofa/Ss), VDAC2 exerts its function by inhibiting autophagy in the ovary. In contrast, Vdac2 knockout promotes autophagy. Moreover, VDAC2-mediated autophagy suppression is dependent on its interactions with both BECN1 and BCL2L1 to stabilize the BECN1 and BCL2L1 complex, suggesting VDAC2 as an autophagy suppressor in the pathway. Our findings provide a functional connection among the VDAC2, MYBL2, the BECN1-BCL2L1 pathway and autophagy suppression in the developing ovary, which is implicated in improving female fecundity.

  6. Autophagy mediated by arginine depletion activation of the nutrient sensor GCN2 contributes to interferon-γ-induced malignant transformation of primary bovine mammary epithelial cells

    Science.gov (United States)

    Xia, X-j; Gao, Y-y; Zhang, J; Wang, L; Zhao, S; Che, Y-y; Ao, C-j; Yang, H-j; Wang, J-q; Lei, L-c

    2016-01-01

    Autophagy has been linked to the regulation of both the prevention and progression of cancer. IFN-γ has been shown to induce autophagy in multiple cell lines in vitro. However, whether IFN-γ can induce autophagy and whether autophagy promotes malignant transformation in healthy lactating bovine mammary epithelial cells (BMECs) remain unclear. Here, we provide the first evidence of the correlation between IFN-γ treatment, autophagy and malignant transformation and of the mechanism underlying IFN-γ-induced autophagy and subsequent malignant transformation in primary BMECs. IFN-γ levels were significantly increased in cattle that received normal long-term dietary corn straw (CS) roughage supplementation. In addition, an increase in autophagy was clearly observed in the BMECs from the mammary tissue of cows expressing high levels of IFN-γ. In vitro, autophagy was clearly induced in primary BMECs by IFN-γ within 24 h. This induced autophagy could subsequently promote dramatic primary BMEC transformation. Furthermore, we found that IFN-γ promoted arginine depletion, activated the general control nonderepressible-2 kinase (GCN2) signalling pathway and resulted in an increase in autophagic flux and the amount of autophagy in BMECs. Overall, our findings are the first to demonstrate that arginine depletion and kinase GCN2 expression mediate IFN-γ-induced autophagy that may promote malignant progression and that immunometabolism, autophagy and cancer are strongly correlated. These results suggest new directions and paths for preventing and treating breast cancer in relation to diet. PMID:27551491

  7. Idarubicin induces mTOR-dependent cytotoxic autophagy in leukemic cells

    Energy Technology Data Exchange (ETDEWEB)

    Ristic, Biljana [Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade (Serbia); Bosnjak, Mihajlo [Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade (Serbia); Arsikin, Katarina [Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade (Serbia); Mircic, Aleksandar; Suzin-Zivkovic, Violeta [Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade (Serbia); Bogdanovic, Andrija [Clinic for Hematology, Clinical Centre of Serbia, School of Medicine, University of Belgrade, Belgrade (Serbia); Perovic, Vladimir [Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade (Serbia); Martinovic, Tamara; Kravic-Stevovic, Tamara; Bumbasirevic, Vladimir [Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade (Serbia); Trajkovic, Vladimir, E-mail: vtrajkovic@med.bg.ac.rs [Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade (Serbia); Harhaji-Trajkovic, Ljubica, E-mail: buajk@yahoo.com [Institute for Biological Research, University of Belgrade, Belgrade, Despot Stefan Blvd. 142, 11000 Belgrade (Serbia)

    2014-08-01

    We investigated if the antileukemic drug idarubicin induces autophagy, a process of programmed cellular self-digestion, in leukemic cell lines and primary leukemic cells. Transmission electron microscopy and acridine orange staining demonstrated the presence of autophagic vesicles and intracellular acidification, respectively, in idarubicin-treated REH leukemic cell line. Idarubicin increased punctuation/aggregation of microtubule-associated light chain 3B (LC3B), enhanced the conversion of LC3B-I to autophagosome-associated LC3B-II in the presence of proteolysis inhibitors, and promoted the degradation of the selective autophagic target p62, thus indicating the increase in autophagic flux. Idarubicin inhibited the phosphorylation of the main autophagy repressor mammalian target of rapamycin (mTOR) and its downstream target p70S6 kinase. The treatment with the mTOR activator leucine prevented idarubicin-mediated autophagy induction. Idarubicin-induced mTOR repression was associated with the activation of the mTOR inhibitor AMP-activated protein kinase and down-regulation of the mTOR activator Akt. The suppression of autophagy by pharmacological inhibitors or LC3B and beclin-1 genetic knockdown rescued REH cells from idarubicin-mediated oxidative stress, mitochondrial depolarization, caspase activation and apoptotic DNA fragmentation. Idarubicin also caused mTOR inhibition and cytotoxic autophagy in K562 leukemic cell line and leukocytes from chronic myeloid leukemia patients, but not healthy controls. By demonstrating mTOR-dependent cytotoxic autophagy in idarubicin-treated leukemic cells, our results warrant caution when considering combining idarubicin with autophagy inhibitors in leukemia therapy. - Highlights: • Idarubicin induces autophagy in leukemic cell lines and primary leukemic cells. • Idarubicin induces autophagy by inhibiting mTOR in leukemic cells. • mTOR suppression by idarubicin is associated with AMPK activation and Akt blockade.

  8. Clock circadian regulator (CLOCK) gene network expression patterns in bovine adipose, liver, and mammary gland at 3 time points during the transition from pregnancy into lactation.

    Science.gov (United States)

    Wang, M; Zhou, Z; Khan, M J; Gao, J; Loor, J J

    2015-07-01

    The transition from late gestation to early lactation is the most critical phase of the lactation cycle for mammals. Research in rodents has revealed changes in the clock circadian regulator (CLOCK) gene network expression around parturition. However, their expression profiles and putative functions during the periparturient period in ruminants remain to be determined. The present study aimed to investigate the expression pattern of the CLOCK network and selected metabolic genes simultaneously in mammary gland (MG), liver (LIV), and subcutaneous adipose tissue (AT). Seven dairy cows were biopsied at -10 (±2), 7, and 21 d relative to parturition. A day × tissue interaction was observed for ARNTL, CRY1, and PER2 due to upregulation at 7 and 21 d postpartum, with their expression being greater in AT and MG compared with LIV. No interaction was detected for CLOCK, CRY2, PER1, and PER3. In general, the expression of NPAS2, NR1D1, NR2F2, ALAS1, FECH, FBXW11, CCRN4L, PPARA, PPARGC1A, and FGF21 was lower at -10 d but increased postpartum in all tissues. The interaction detected for CSNK1D was associated with increased expression postpartum in AT and MG but not LIV. The interaction detected for CPT1A was due to upregulation in AT and LIV postpartum without a change in MG. In contrast, the interaction for PPARG was due to upregulation in AT and MG postpartum but a downregulation in LIV. Leptin was barely detectable in LIV, but there was an interaction effect in AT and MG associated with upregulation postpartum in MG and downregulation in AT. Together, these results suggest that the control of metabolic adaptations in LIV, MG, and AT around parturition might be partly regulated through the CLOCK gene network. Although the present study did not specifically address rhythmic control of tissue metabolism via the CLOCK gene network, the difference in expression of genes studied among tissues confirms that the behavior of circadian-controlled metabolic genes around parturition

  9. Sinomenine Hydrochloride Protects against Polymicrobial Sepsis via Autophagy

    Directory of Open Access Journals (Sweden)

    Yu Jiang

    2015-01-01

    Full Text Available Sepsis, a systemic inflammatory response to infection, is the major cause of death in intensive care units (ICUs. The mortality rate of sepsis remains high even though the treatment and understanding of sepsis both continue to improve. Sinomenine (SIN is a natural alkaloid extracted from Chinese medicinal plant Sinomenium acutum, and its hydrochloride salt (Sinomenine hydrochloride, SIN-HCl is widely used to treat rheumatoid arthritis (RA. However, its role in sepsis remains unclear. In the present study, we investigated the role of SIN-HCl in sepsis induced by cecal ligation and puncture (CLP in BALB/c mice and the corresponding mechanism. SIN-HCl treatment improved the survival of BALB/c mice that were subjected to CLP and reduced multiple organ dysfunction and the release of systemic inflammatory mediators. Autophagy activities were examined using Western blotting. The results showed that CLP-induced autophagy was elevated, and SIN-HCl treatment further strengthened the autophagy activity. Autophagy blocker 3-methyladenine (3-MA was used to investigate the mechanism of SIN-HCl in vitro. Autophagy activities were determined by examining the autophagosome formation, which was shown as microtubule-associated protein light chain 3 (LC3 puncta with green immunofluorescence. SIN-HCl reduced lipopolysaccharide (LPS-induced inflammatory cytokine release and increased autophagy in peritoneal macrophages (PM. 3-MA significantly decreased autophagosome formation induced by LPS and SIN-HCl. The decrease of inflammatory cytokines caused by SIN-HCl was partially aggravated by 3-MA treatment. Taken together, our results indicated that SIN-HCl could improve survival, reduce organ damage, and attenuate the release of inflammatory cytokines induced by CLP, at least in part through regulating autophagy activities.

  10. Sinomenine hydrochloride protects against polymicrobial sepsis via autophagy.

    Science.gov (United States)

    Jiang, Yu; Gao, Min; Wang, Wenmei; Lang, Yuejiao; Tong, Zhongyi; Wang, Kangkai; Zhang, Huali; Chen, Guangwen; Liu, Meidong; Yao, Yongming; Xiao, Xianzhong

    2015-01-23

    Sepsis, a systemic inflammatory response to infection, is the major cause of death in intensive care units (ICUs). The mortality rate of sepsis remains high even though the treatment and understanding of sepsis both continue to improve. Sinomenine (SIN) is a natural alkaloid extracted from Chinese medicinal plant Sinomenium acutum, and its hydrochloride salt (Sinomenine hydrochloride, SIN-HCl) is widely used to treat rheumatoid arthritis (RA). However, its role in sepsis remains unclear. In the present study, we investigated the role of SIN-HCl in sepsis induced by cecal ligation and puncture (CLP) in BALB/c mice and the corresponding mechanism. SIN-HCl treatment improved the survival of BALB/c mice that were subjected to CLP and reduced multiple organ dysfunction and the release of systemic inflammatory mediators. Autophagy activities were examined using Western blotting. The results showed that CLP-induced autophagy was elevated, and SIN-HCl treatment further strengthened the autophagy activity. Autophagy blocker 3-methyladenine (3-MA) was used to investigate the mechanism of SIN-HCl in vitro. Autophagy activities were determined by examining the autophagosome formation, which was shown as microtubule-associated protein light chain 3 (LC3) puncta with green immunofluorescence. SIN-HCl reduced lipopolysaccharide (LPS)-induced inflammatory cytokine release and increased autophagy in peritoneal macrophages (PM). 3-MA significantly decreased autophagosome formation induced by LPS and SIN-HCl. The decrease of inflammatory cytokines caused by SIN-HCl was partially aggravated by 3-MA treatment. Taken together, our results indicated that SIN-HCl could improve survival, reduce organ damage, and attenuate the release of inflammatory cytokines induced by CLP, at least in part through regulating autophagy activities.

  11. Live and Let Die: Roles of Autophagy in Cadmium Nephrotoxicity

    Directory of Open Access Journals (Sweden)

    Frank Thévenod

    2015-04-01

    Full Text Available The transition metal ion cadmium (Cd2+ is a significant environmental contaminant. With a biological half-life of ~20 years, Cd2+ accumulates in the kidney cortex, where it particularly damages proximal tubule (PT cells and can result in renal fibrosis, failure, or cancer. Because death represents a powerful means by which cells avoid malignant transformation, it is crucial to clearly identify and understand the pathways that determine cell fate in chronic Cd2+ nephrotoxicity. When cells are subjected to stress, they make a decision to adapt and survive, or—depending on the magnitude and duration of stress—to die by several modes of death (programmed cell death, including autophagic cell death (ACD. Autophagy is part of a larger system of intracellular protein degradation and represents the channel by which organelles and long-lived proteins are delivered to the lysosome for degradation. Basal autophagy levels in all eukaryotic cells serve as a dynamic physiological recycling system, but they can also be induced by intra- or extracellular stress and pathological processes, such as endoplasmic reticulum (ER stress. In a context-dependent manner, autophagy can either be protective and hence contribute to survival, or promote death by non-apoptotic or apoptotic pathways. So far, the role of autophagy in Cd2+-induced nephrotoxicity has remained unsettled due to contradictory results. In this review, we critically survey the current literature on autophagy in Cd2+-induced nephrotoxicity in light of our own ongoing studies. Data obtained in kidney cells illustrate a dual and complex function of autophagy in a stimulus- and time-dependent manner that possibly reflects distinct outcomes in vitro and in vivo. A better understanding of the context-specific regulation of cell fate by autophagy may ultimately contribute to the development of preventive and novel therapeutic strategies for acute and chronic Cd2+ nephrotoxicity.

  12. ATG12-ATG3 connects basal autophagy and late endosome function.

    Science.gov (United States)

    Murrow, Lyndsay; Debnath, Jayanta

    2015-01-01

    In addition to supporting cell survival in response to starvation or stress, autophagy promotes basal protein and organelle turnover. Compared to our understanding of stress-induced autophagy, little is known about how basal autophagy is regulated and how its activity is coordinated with other cellular processes. We recently identified a novel interaction between the ATG12-ATG3 conjugate and the ESCRT-associated protein PDCD6IP/Alix that promotes basal autophagy and endolysosomal trafficking. Moreover, ATG12-ATG3 is required for diverse PDCD6IP-mediated functions including late endosome distribution, exosome secretion, and viral budding. Our results highlight the importance of late endosomes for basal autophagic flux and reveal distinct roles for the core autophagy proteins ATG12 and ATG3 in controlling late endosome function.

  13. miR-224-3p inhibits autophagy in cervical cancer cells by targeting FIP200

    Science.gov (United States)

    Fang, Wang; Shu, Shan; Yongmei, Li; Endong, Zhu; Lirong, Yin; Bei, Sun

    2016-01-01

    Cervical cancer (CC) is a malignant solid tumor, which is one of the main causes of morbidity and mortality in women. Persistent High-risk human papillomavirus (hrHPV) infection is closely related to cervical cancer and autophagy has been suggested to inhibit viral infections. miRNAs have been reported to regulate autophagy in many solid tumors with many studies implicating miR-224-3p in the regulation of autophagy. In this study, we performed a miRNA microarray analysis on CC tissues and found that a large number of miRNAs with differential expressions in hrHPV-infected tissues. We identified miR-224-3p as a candidate miRNA selectively up regulated in HPV-infected tissues and cell lines. Further analysis revealed that miR-224-3p regulates autophagy in cervical cancer tissues and cell lines. While the overexpression of miR-224-3p inhibits autophagy in HPV-infected cells, knocking down endogenous miR-224-3p increases autophagy activity in the same cells. In addition, we found that miR-224-3p directly inhibits the expression of autophagy related gene, FAK family-interacting protein of 200 kDa (FIP200). In summary, we found that miR-224-3p regulates autophagy in hrHPV-induced cervical cancer cells through targeting FIP200 expression. PMID:27615604

  14. miR-224-3p inhibits autophagy in cervical cancer cells by targeting FIP200.

    Science.gov (United States)

    Fang, Wang; Shu, Shan; Yongmei, Li; Endong, Zhu; Lirong, Yin; Bei, Sun

    2016-01-01

    Cervical cancer (CC) is a malignant solid tumor, which is one of the main causes of morbidity and mortality in women. Persistent High-risk human papillomavirus (hrHPV) infection is closely related to cervical cancer and autophagy has been suggested to inhibit viral infections. miRNAs have been reported to regulate autophagy in many solid tumors with many studies implicating miR-224-3p in the regulation of autophagy. In this study, we performed a miRNA microarray analysis on CC tissues and found that a large number of miRNAs with differential expressions in hrHPV-infected tissues. We identified miR-224-3p as a candidate miRNA selectively up regulated in HPV-infected tissues and cell lines. Further analysis revealed that miR-224-3p regulates autophagy in cervical cancer tissues and cell lines. While the overexpression of miR-224-3p inhibits autophagy in HPV-infected cells, knocking down endogenous miR-224-3p increases autophagy activity in the same cells. In addition, we found that miR-224-3p directly inhibits the expression of autophagy related gene, FAK family-interacting protein of 200 kDa (FIP200). In summary, we found that miR-224-3p regulates autophagy in hrHPV-induced cervical cancer cells through targeting FIP200 expression. PMID:27615604

  15. Autophagy and neurodegenerative disorders

    Institute of Scientific and Technical Information of China (English)

    Evangelia Kesidou; Roza Lagoudaki; Olga Touloumi; Kyriaki-Nefeli Poulatsidou; Constantina Simeonidou

    2013-01-01

    Accumulation of aberrant proteins and inclusion bodies are hallmarks in most neurodegenerative diseases. Consequently, these aggregates within neurons lead to toxic effects, overproduction of reactive oxygen species and oxidative stress. Autophagy is a significant intracel ular mechanism that removes damaged organelles and misfolded proteins in order to maintain cel homeostasis. Excessive or insufficient autophagic activity in neurons leads to altered homeostasis and influences their survival rate, causing neurodegeneration. The review article provides an update of the role of autophagic process in representative chronic and acute neurodegenerative disorders.

  16. Heme oxygenase-1 enhances autophagy in podocytes as a protective mechanism against high glucose-induced apoptosis

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Chenglong [Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing (China); Zheng, Haining [Department of Hyperbaric Oxygen, Nanjing General Hospital of Nanjing Military Command, Nanjing (China); Huang, Shanshan; You, Na; Xu, Jiarong; Ye, Xiaolong; Zhu, Qun; Feng, Yamin; You, Qiang; Miao, Heng [Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing (China); Ding, Dafa, E-mail: dingdafa2004@aliyun.com [Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing (China); Lu, Yibing, E-mail: luyibing2004@126.com [Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing (China)

    2015-10-01

    Injury and loss of podocytes play vital roles in diabetic nephropathy progression. Emerging evidence suggests autophagy, which is induced by multiple stressors including hyperglycemia, plays a protective role. Meanwhile, heme oxygenase-1 (HO-1) possesses powerful anti-apoptotic properties. Therefore, we investigated the impact of autophagy on podocyte apoptosis under diabetic conditions and its association with HO-1. Mouse podocytes were cultured in vitro; apoptosis was detected by flow cytometry. Transmission electron microscopy and biochemical autophagic flux assays were used to measure the autophagy markers microtubule-associated protein 1 light chain 3-II (LC3-II) and beclin-1. LC3-II and beclin-1 expression peaked 12–24 h after exposing podocytes to high glucose. Inhibition of autophagy with 3-methyladenine or Beclin-1 siRNAs or Atg 5 siRNAs sensitized cells to apoptosis, suggesting autophagy is a survival mechanism. HO-1 inactivation inhibited autophagy, which aggravated podocyte injury in vitro. Hemin-induced autophagy also protected podocytes from hyperglycemia in vitro and was abrogated by HO-1 siRNA. Adenosine monophosphate-activated protein kinase phosphorylation was higher in hemin-treated and lower in HO-1 siRNA-treated podocytes. Suppression of AMPK activity reversed HO-1-mediated Beclin-1 upregulation and autophagy, indicating HO-1-mediated autophagy is AMPK dependent. These findings suggest HO-1 induction and regulation of autophagy are potential therapeutic targets for diabetic nephropathy. - Highlights: • High glucose leads to increased autophagy in podocytes at an early stage. • The early autophagic response protects against high glucose-induced apoptosis. • Heme oxygenase-1 enhances autophagy and decreases high glucose -mediated apoptosis. • Heme oxygenase-1 induces autophagy through the activation of AMPK.

  17. The yeast Saccharomyces cerevisiae: an overview of methods to study autophagy progression

    Science.gov (United States)

    Delorme-Axford, Elizabeth; Guimaraes, Rodrigo Soares; Reggiori, Fulvio; Klionsky, Daniel J.

    2014-01-01

    Macroautophagy (hereafter autophagy) is a highly evolutionarily conserved process essential for sustaining cellular integrity, homeostasis, and survival. Most eukaryotic cells constitutively undergo autophagy at a low basal level. However, various stimuli, including starvation, organelle deterioration, stress, and pathogen infection, potently upregulate autophagy. The hallmark morphological feature of autophagy is the formation of the double-membrane vesicle known as the autophagosome. In yeast, flux through the pathway culminates in autophagosome-vacuole fusion, and the subsequent degradation of the resulting autophagic bodies and cargo by vacuolar hydrolases, followed by efflux of the breakdown products. Importantly, aberrant autophagy is associated with diverse human pathologies. Thus, there is a need for ongoing work in this area to further understand the cellular factors regulating this process. The field of autophagy research has grown exponentially in recent years, and although numerous model organisms are being used to investigate autophagy, the baker’s yeast Saccharomyces cerevisiae remains highly relevant, as there are significant and unique benefits to working with this organism. In this review, we will focus on the current methods available to evaluate and monitor autophagy in S. cerevisiae, which in several cases have also been subsequently exploited in higher eukaryotes. PMID:25526918

  18. Erythropoietin protects epithelial cells from excessive autophagy and apoptosis in experimental neonatal necrotizing enterocolitis.

    Directory of Open Access Journals (Sweden)

    Yueyue Yu

    Full Text Available Neonatal necrotizing enterocolitis (NEC is a devastating gastrointestinal disease of preterm infants. Increased intestinal epithelium permeability is an early event in NEC pathogenesis. Autophagy and apoptosis are induced by multiple stress pathways which may impact the intestinal barrier, and they have been associated with pathogenesis of diverse gastrointestinal diseases including inflammatory bowel disease. Using both in vitro and in vivo models, this study investigates autophagy and apoptosis under experimental NEC stresses. Furthermore this study evaluates the effect of erythropoietin (Epo, a component of breast milk previously shown to decrease the incidence of NEC and to preserve intestinal barrier function, on intestinal autophagy and apoptosis. It was found that autophagy and apoptosis are both rapidly up regulated in NEC in vivo as indicated by increased expression of the autophagy markers Beclin 1 and LC3II, and by evidence of apoptosis by TUNEL and cleaved caspase-3 staining. In the rat NEC experimental model, autophagy preceded the onset of apoptosis in intestine. In vitro studies suggested that Epo supplementation significantly decreased both autophagy and apoptosis via the Akt/mTOR signaling pathway and the MAPK/ERK pathway respectively. These results suggest that Epo protects intestinal epithelium from excessive autophagy and apoptosis in experimental NEC.

  19. Evolutionary trends and functional anatomy of the human expanded autophagy network.

    Science.gov (United States)

    Till, Andreas; Saito, Rintaro; Merkurjev, Daria; Liu, Jing-Jing; Syed, Gulam Hussain; Kolnik, Martin; Siddiqui, Aleem; Glas, Martin; Scheffler, Björn; Ideker, Trey; Subramani, Suresh

    2015-01-01

    All eukaryotic cells utilize autophagy for protein and organelle turnover, thus assuring subcellular quality control, homeostasis, and survival. In order to address recent advances in identification of human autophagy associated genes, and to describe autophagy on a system-wide level, we established an autophagy-centered gene interaction network by merging various primary data sets and by retrieving respective interaction data. The resulting network ('AXAN') was analyzed with respect to subnetworks, e.g. the prime gene subnetwork (including the core machinery, signaling pathways and autophagy receptors) and the transcription subnetwork. To describe aspects of evolution within this network, we assessed the presence of protein orthologs across 99 eukaryotic model organisms. We visualized evolutionary trends for prime gene categories and evolutionary tracks for selected AXAN genes. This analysis confirms the eukaryotic origin of autophagy core genes while it points to a diverse evolutionary history of autophagy receptors. Next, we used module identification to describe the functional anatomy of the network at the level of pathway modules. In addition to obvious pathways (e.g., lysosomal degradation, insulin signaling) our data unveil the existence of context-related modules such as Rho GTPase signaling. Last, we used a tripartite, image-based RNAi - screen to test candidate genes predicted to play a role in regulation of autophagy. We verified the Rho GTPase, CDC42, as a novel regulator of autophagy-related signaling. This study emphasizes the applicability of system-wide approaches to gain novel insights into a complex biological process and to describe the human autophagy pathway at a hitherto unprecedented level of detail.

  20. The Adipose Tissue in Farm Animals

    DEFF Research Database (Denmark)

    Sauerwein, Helga; Bendixen, Emoke; Restelli, Laura;

    2014-01-01

    Adipose tissue is not only a tissue where energy is stored but is also involved in regulating several body functions such as appetite and energy expenditure via its endocrine activity. Moreover, it thereby modulates complex processes like reproduction, inflammation and immune response. The products...... secreted from adipose tissue comprise hormones and cytokines that are collectively termed as adipocytokines or "adipokines"; the discovery and characterization of new proteins secreted by adipose tissue is still ongoing and their number is thus increasing. Adipokines act in both endocrine manner as well...... as locally, as autocrine or paracrine effectors. Proteomics has emerged as a valuable technique to characterize both cellular and secreted proteomes from adipose tissues, including those of main cellular fractions, i.e. the adipocytes or the stromal vascular fraction containing mainly adipocyte precursors...

  1. Autophagy and Tumor%自噬与肿瘤

    Institute of Scientific and Technical Information of China (English)

    王宗鼎

    2011-01-01

    自噬(autophagy)作为细胞一种基本生物学特征,具有独特的形态学改变和特有的调控通路.近年来,自噬在关于对肿瘤的作用的研究已成为热点,在不同的种类肿瘤中,自噬扮演着不同的角色,分为促进和抑制肿瘤两种作用.自噬异常与人类恶性肿瘤的发生、发展联系紧密,其启动及调节与细胞能量代谢、微环境变化、抑癌基因及癌基因家族及复杂的信号调节等有关.清楚了解自噬的特点可为肿瘤治疗提供新的方向.%As a basic biological characteristic of cells, autophagy corresponds with specific morphological changes and a specific regulating pathways. In recent years autophagy has become a hot topic, in part due to its roles in both promoting and preventing neoplasms. Irregularities in autophagy in humans are closely linked to the occurrence of malignant neoplasms. Activation and regulation of autophagy influence not only cellular metabolism, but also microenvironments, antioncogene and oncogene function as well as complex signaling pathways. A clear understanding of autophagy would provide new approaches to the treatment of neoplasms.

  2. Disruption of Inducible 6-Phosphofructo-2-kinase Ameliorates Diet-induced Adiposity but Exacerbates Systemic Insulin Resistance and Adipose Tissue Inflammatory Response*

    OpenAIRE

    Huo, Yuqing; Guo, Xin; Li, Honggui; Wang, Huan; Zhang, Weiyu; Wang, Ying; Zhou, Huaijun; Gao, Zhanguo; Telang, Sucheta; Chesney, Jason; Chen, Y. Eugene; Ye, Jianping; Chapkin, Robert S.; Wu, Chaodong

    2009-01-01

    Adiposity is commonly associated with adipose tissue dysfunction and many overnutrition-related metabolic diseases including type 2 diabetes. Much attention has been paid to reducing adiposity as a way to improve adipose tissue function and systemic insulin sensitivity. PFKFB3/iPFK2 is a master regulator of adipocyte nutrient metabolism. Using PFKFB3+/− mice, the present study investigated the role of PFKFB3/iPFK2 in regulating diet-induced adiposity and systemic insulin resistance. On a high...

  3. Meta-review of protein network regulating obesity between validated obesity candidate genes in the white adipose tissue of high-fat diet-induced obese C57BL/6J mice.

    Science.gov (United States)

    Kim, Eunjung; Kim, Eun Jung; Seo, Seung-Won; Hur, Cheol-Goo; McGregor, Robin A; Choi, Myung-Sook

    2014-01-01

    Worldwide obesity and related comorbidities are increasing, but identifying new therapeutic targets remains a challenge. A plethora of microarray studies in diet-induced obesity models has provided large datasets of obesity associated genes. In this review, we describe an approach to examine the underlying molecular network regulating obesity, and we discuss interactions between obesity candidate genes. We conducted network analysis on functional protein-protein interactions associated with 25 obesity candidate genes identified in a literature-driven approach based on published microarray studies of diet-induced obesity. The obesity candidate genes were closely associated with lipid metabolism and inflammation. Peroxisome proliferator activated receptor gamma (Pparg) appeared to be a core obesity gene, and obesity candidate genes were highly interconnected, suggesting a coordinately regulated molecular network in adipose tissue. In conclusion, the current network analysis approach may help elucidate the underlying molecular network regulating obesity and identify anti-obesity targets for therapeutic intervention.

  4. Fat metabolism is regulated by altered gene expression of lipogenic enzymes and regulatory factors in liver and adipose tissue but not in semimembranosus muscle of pigs during the fattening period.

    Science.gov (United States)

    Duran-Montgé, P; Theil, P K; Lauridsen, C; Esteve-Garcia, E

    2009-11-01

    It has been shown previously that lipid metabolism is regulated by fatty acids (FA) and that thyroid hormones are important regulators of energy metabolism. The effects of weight, dietary fat level and dietary FA profile on thyroid hormone levels and expression of lipogenic genes and tissue FA composition were studied. Sixty-one crossbred gilts weighing 62 ± 5.2 kg BW average were either slaughtered at the beginning of the trial (n = 5) or fed one of seven diets (n = 8 pigs per diet): a semi-synthetic diet formulated to contain a very low level of fat (NF) and six diets based on barley-soybean meal supplemented with approximately 10% fat of different origin and slaughtered at 100 kg BW. The supplemental fats were tallow, high-oleic sunflower oil, sunflower oil (SFO), linseed oil, fat blend (55% tallow, 35% sunflower oil, 10% linseed oil) and fish oil blend (40% fish oil, 60% linseed oil). In general, the dietary FA profiles altered the FA composition of liver, semimembranosus muscle and adipose tissues. Pigs fed the NF diet had the highest free and total triiodothyronine (T3) values followed by pigs fed SFO. Total T3 levels were higher in pigs at 60 kg than in pigs at 100 kg. Correlations between thyroid hormones and genes encoding enzymes of fat synthesis in adipose tissue (acetyl CoA carboxylase (ACACA), fatty acid synthase and stearoyl CoA desaturase (SCD)) and the large differences in expression of lipogenic genes at different weights (60 and 100 kg BW), suggest a role for thyroid hormones and for T3, in particular, in regulating whole animal fat metabolism, with effects brought about by altered expression of lipogenic genes. Liver sterol receptor element binding protein-1 (SREBP1) mRNA content was affected by dietary treatment (P influence on mRNA abundance of genes related with lipid metabolism