Regulation of T Cell Differentiation and Function by EZH2

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Karantanos, Theodoros; Christofides, Anthos; Bardhan, Kankana; Li, Lequn; Boussiotis, Vassiliki A.

2016-01-01

The enhancer of zeste homolog 2 (EZH2), one of the polycomb-group proteins, is the catalytic subunit of Polycomb-repressive complex 2 (PRC2) and induces the trimethylation of the histone H3 lysine 27 (H3K27me3) promoting epigenetic gene silencing. EZH2 contains a SET domain promoting the methyltransferase activity, while the three other protein components of PRC2, namely EED, SUZ12, and RpAp46/48, induce compaction of the chromatin permitting EZH2 enzymatic activity. Numerous studies highlight the role of this evolutionary conserved protein as a master regulator of differentiation in humans involved in the repression of the homeotic gene and the inactivation of X-chromosome. Through its effects in the epigenetic regulation of critical genes, EZH2 has been strongly linked to cell cycle progression, stem cell pluripotency, and cancer biology, being currently at the cutting edge of research. Most recently, EZH2 has been associated with hematopoietic stem cell proliferation and differentiation, thymopoiesis and lymphopoiesis. Several studies have evaluated the role of EZH2 in the regulation of T cell differentiation and plasticity as well as its implications in the development of autoimmune diseases and graft-versus-host disease (GVHD). The aim of this review is to summarize the current knowledge regarding the role of EZH2 in the regulation of the differentiation and function of T cells focusing on possible applications in various immune-mediated conditions, including autoimmune disorders and GVHD. PMID:27199994

Diacylglycerol Kinases: Regulated Controllers of T Cell Activation, Function, and Development

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Gary A. Koretzky

2013-03-01

Full Text Available Diacylglycerol kinases (DGKs are a diverse family of enzymes that catalyze the conversion of diacylglycerol (DAG, a crucial second messenger of receptor-mediated signaling, to phosphatidic acid (PA. Both DAG and PA are bioactive molecules that regulate a wide set of intracellular signaling proteins involved in innate and adaptive immunity. Clear evidence points to a critical role for DGKs in modulating T cell activation, function, and development. More recently, studies have elucidated factors that control DGK function, suggesting an added complexity to how DGKs act during signaling. This review summarizes the available knowledge of the function and regulation of DGK isoforms in signal transduction with a particular focus on T lymphocytes.

Physiological Functions and Regulation of the Na+/H+ Exchanger [NHE1] in Renal Tubule Epithelial Cells

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Patricia G Vallés

2015-08-01

Full Text Available The sodium-hydrogen exchanger isoform-1 [NHE1] is a ubiquitously expressed plasma membrane protein that plays a central role in intracellular pH and cell volume homeostasis by catalyzing an electroneutral exchange of extracellular sodium and intracellular hydrogen. Outside of this important physiological function, the NHE1 cytosolic tail domain acts as a molecular scaffold regulating cell survival and actin cytoskeleton organization through NHE1-dependent signaling proteins. NHE1 plays main roles in response to physiological stress conditions which in addition to cell shrinkage and acidification, include hypoxia and mechanical stimuli, such as cell stretch. NHE1-mediated modulation of programmed cell death results from the exchanger-mediated changes in pHi, cell volume, and/or [Na+]I; and, it has recently become known that regulation of cellular signaling pathways are involved as well. This review focuses on NHE1 functions and regulations. We describe evidence showing how these structural actions integrate with ion translocation in regulating renal tubule epithelial cell survival.

New insights into Blimp-1 in T lymphocytes: a divergent regulator of cell destiny and effector function.

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Fu, Shin-Huei; Yeh, Li-Tzu; Chu, Chin-Chen; Yen, B Lin-Ju; Sytwu, Huey-Kang

2017-07-21

B lymphocyte-induced maturation protein-1 (Blimp-1) serves as a master regulator of the development and function of antibody-producing B cells. Given that its function in T lymphocytes has been identified within the past decade, we review recent findings with emphasis on its role in coordinated control of gene expression during the development, differentiation, and function of T cells. Expression of Blimp-1 is mainly confined to activated T cells and is essential for the production of interleukin (IL)-10 by a subset of forkhead box (Fox)p3 + regulatory T cells with an effector phenotype. Blimp-1 is also required to induce cell elimination in the thymus and critically modulates peripheral T cell activation and proliferation. In addition, Blimp-1 promotes T helper (Th) 2 lineage commitment and limits Th1, Th17 and follicular helper T cell differentiation. Furthermore, Blimp-1 coordinates with other transcription factors to regulate expression of IL-2, IL-21 and IL-10 in effector T lymphocytes. In CD8 + T cells, Blimp-1 expression is distinct in heterogeneous populations at the stages of clonal expansion, differentiation, contraction and memory formation when they encounter antigens. Moreover, Blimp-1 plays a fundamental role in coordinating cytokine receptor signaling networks and transcriptional programs to regulate diverse aspects of the formation and function of effector and memory CD8 + T cells and their exhaustion. Blimp-1 also functions as a gatekeeper of T cell activation and suppression to prevent or dampen autoimmune disease, antiviral responses and antitumor immunity. In this review, we discuss the emerging roles of Blimp-1 in the complex regulation of gene networks that regulate the destiny and effector function of T cells and provide a Blimp-1-dominated transcriptional framework for T lymphocyte homeostasis.

Matrix regulators in neural stem cell functions.

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Wade, Anna; McKinney, Andrew; Phillips, Joanna J

2014-08-01

Neural stem/progenitor cells (NSPCs) reside within a complex and dynamic extracellular microenvironment, or niche. This niche regulates fundamental aspects of their behavior during normal neural development and repair. Precise yet dynamic regulation of NSPC self-renewal, migration, and differentiation is critical and must persist over the life of an organism. In this review, we summarize some of the major components of the NSPC niche and provide examples of how cues from the extracellular matrix regulate NSPC behaviors. We use proteoglycans to illustrate the many diverse roles of the niche in providing temporal and spatial regulation of cellular behavior. The NSPC niche is comprised of multiple components that include; soluble ligands, such as growth factors, morphogens, chemokines, and neurotransmitters, the extracellular matrix, and cellular components. As illustrated by proteoglycans, a major component of the extracellular matrix, the NSPC, niche provides temporal and spatial regulation of NSPC behaviors. The factors that control NSPC behavior are vital to understand as we attempt to modulate normal neural development and repair. Furthermore, an improved understanding of how these factors regulate cell proliferation, migration, and differentiation, crucial for malignancy, may reveal novel anti-tumor strategies. This article is part of a Special Issue entitled Matrix-mediated cell behaviour and properties. Copyright © 2014 Elsevier B.V. All rights reserved.

Blimp-1 controls plasma cell function through regulation of immunoglobulin secretion and the unfolded protein response

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Tellier, Julie; Shi, Wei; Minnich, Martina; Liao, Yang; Crawford, Simon; Smyth, Gordon K; Kallies, Axel; Busslinger, Meinrad; Nutt, Stephen L

2015-01-01

Plasma cell differentiation requires silencing of B cell transcription, while establishing antibody-secretory function and long-term survival. The transcription factors Blimp-1 and IRF4 are essential for plasma cell generation, however their function in mature plasma cells has remained elusive. We have found that while IRF4 was essential for plasma cell survival, Blimp-1 was dispensable. Blimp-1-deficient plasma cells retained their transcriptional identity, but lost the ability to secrete antibody. Blimp-1 regulated many components of the unfolded protein response (UPR), including XBP-1 and ATF6. The overlap of Blimp-1 and XBP-1 function was restricted to the UPR, with Blimp-1 uniquely regulating mTOR activity and plasma cell size. Thus, Blimp-1 is required for the unique physiological capacity of plasma cells that enables the secretion of protective antibody. PMID:26779600

Function and Regulation of Yeast Ribonucleotide Reductase: Cell Cycle, Genotoxic Stress, and Iron Bioavailability

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Nerea Sanvisens

2013-04-01

Full Text Available Ribonucleotide reductases (RNRs are essential enzymes that catalyze the reduction of ribonucleotides to desoxyribonucleotides, thereby providing the building blocks required for de novo DNA biosynthesis. The RNR function is tightly regulated because an unbalanced or excessive supply of deoxyribonucleoside triphosphates (dNTPs dramatically increases the mutation rates during DNA replication and repair that can lead to cell death or genetic anomalies. In this review, we focus on Saccharomyces cerevisiae class Ia RNR as a model to understand the different mechanisms controlling RNR function and regulation in eukaryotes. Many studies have contributed to our current understanding of RNR allosteric regulation and, more recently, to its link to RNR oligomerization. Cells have developed additional mechanisms that restrict RNR activity to particular periods when dNTPs are necessary, such as the S phase or upon genotoxic stress. These regulatory strategies include the transcriptional control of the RNR gene expression, inhibition of RNR catalytic activity, and the subcellular redistribution of RNR subunits. Despite class Ia RNRs requiring iron as an essential cofactor for catalysis, little is known about RNR function regulation depending on iron bioavailability. Recent studies into yeast have deciphered novel strategies for the delivery of iron to RNR and for its regulation in response to iron deficiency. Taken together, these studies open up new possibilities to explore in order to limit uncontrolled tumor cell proliferation via RNR.

ADAM10 regulates Notch function in intestinal stem cells of mice.

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Tsai, Yu-Hwai; VanDussen, Kelli L; Sawey, Eric T; Wade, Alex W; Kasper, Chelsea; Rakshit, Sabita; Bhatt, Riha G; Stoeck, Alex; Maillard, Ivan; Crawford, Howard C; Samuelson, Linda C; Dempsey, Peter J

2014-10-01

A disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) is a cell surface sheddase that regulates physiologic processes, including Notch signaling. ADAM10 is expressed in all intestinal epithelial cell types, but the requirement for ADAM10 signaling in crypt homeostasis is not well defined. We analyzed intestinal tissues from mice with constitutive (Vil-Cre;Adam10(f/f) mice) and conditional (Vil-CreER;Adam10(f/f) and Leucine-rich repeat-containing GPCR5 [Lgr5]-CreER;Adam10(f/f) mice) deletion of ADAM10. We performed cell lineage-tracing experiments in mice that expressed a gain-of-function allele of Notch in the intestine (Rosa26(NICD)), or mice with intestine-specific disruption of Notch (Rosa26(DN-MAML)), to examine the effects of ADAM10 deletion on cell fate specification and intestinal stem cell maintenance. Loss of ADAM10 from developing and adult intestine caused lethality associated with altered intestinal morphology, reduced progenitor cell proliferation, and increased secretory cell differentiation. ADAM10 deletion led to the replacement of intestinal cell progenitors with 2 distinct, post-mitotic, secretory cell lineages: intermediate-like (Paneth/goblet) and enteroendocrine cells. Based on analysis of Rosa26(NICD) and Rosa26(DN-MAML) mice, we determined that ADAM10 controls these cell fate decisions by regulating Notch signaling. Cell lineage-tracing experiments showed that ADAM10 is required for survival of Lgr5(+) crypt-based columnar cells. Our findings indicate that Notch-activated stem cells have a competitive advantage for occupation of the stem cell niche. ADAM10 acts in a cell autonomous manner within the intestinal crypt compartment to regulate Notch signaling. This process is required for progenitor cell lineage specification and crypt-based columnar cell maintenance. Copyright © 2014 AGA Institute. Published by Elsevier Inc. All rights reserved.

Hypoxia and hypoxia-inducible factors as regulators of T cell development, differentiation, and function

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McNamee, Eóin N.; Johnson, Darlynn Korns; Homann, Dirk

2014-01-01

Oxygen is a molecule that is central to cellular respiration and viability, yet there are multiple physiologic and pathological contexts in which cells experience conditions of insufficient oxygen availability, a state known as hypoxia. Given the metabolic challenges of a low oxygen environment, hypoxia elicits a range of adaptive responses at the cellular, tissue, and systemic level to promote continued survival and function. Within this context, T lymphocytes are a highly migratory cell type of the adaptive immune system that frequently encounters a wide range of oxygen tensions in both health and disease. It is now clear that oxygen availability regulates T cell differentiation and function, a response orchestrated in large part by the hypoxia-inducible factor transcription factors. Here, we discuss the physiologic scope of hypoxia and hypoxic signaling, the contribution of these pathways in regulating T cell biology, and current gaps in our understanding. Finally, we discuss how emerging therapies that modulate the hypoxic response may offer new modalities to alter T cell function and the outcome of acute and chronic pathologies. PMID:22961658

Functioning of spontaneous and induced Con A regulators of T-cell proliferation. Modifying factors

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Kuz'mina, E.G.

1989-01-01

It is shown that active spontaneous non-specific regulators of T-cell proliferation are activated in peripheral blood ''in vivo'' by endogenous metabolites; non-specific regulator action can be induced ''in vitro'' by Con A, FGA. Non-specific regulators suppress and increase lymphocyte proliferation. Cyclic character of their functioning is revealed. 4 refs.; 1 tab

KLF2 in Regulation of NF-κB-Mediated Immune Cell Function and Inflammation

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Prerana Jha

2017-11-01

Full Text Available KLF2 (Kruppel-like factor 2 is a member of the zinc finger transcription factor family, which critically regulates embryonic lung development, function of endothelial cells and maintenance of quiescence in T-cells and monocytes. It is expressed in naïve T-cells and monocytes, however its level of expression decreases during activation and differentiation. KLF2 also plays critical regulatory role in various inflammatory diseases and their pathogenesis. Nuclear factor-kappaB (NF-κB is an important inducer of inflammation and the inflammation is mediated through the transcription of several proinflammatory cytokines, chemokines and adhesion molecules. So, both transcriptional factors KLF2 and NF-κB are being associated with the similar cellular functions and their maintenance. It was shown that KLF2 regulates most of the NF-κB-mediated activities. In this review, we focused on emphasizing the involvement of KLF2 in health and disease states and how they interact with transcriptional master regulator NF-κB.

Regulation of defensive function on gingival epithelial cells can prevent periodontal disease.

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Fujita, Tsuyoshi; Yoshimoto, Tetsuya; Kajiya, Mikihito; Ouhara, Kazuhisa; Matsuda, Shinji; Takemura, Tasuku; Akutagawa, Keiichi; Takeda, Katsuhiro; Mizuno, Noriyoshi; Kurihara, Hidemi

2018-05-01

Periodontal disease is a bacterial biofilm-associated inflammatory disease that has been implicated in many systemic diseases. A new preventive method for periodontal disease needs to be developed in order to promote the health of the elderly in a super-aged society. The gingival epithelium plays an important role as a mechanical barrier against bacterial invasion and a part of the innate immune response to infectious inflammation in periodontal tissue. The disorganization of cell-cell interactions and subsequent inflammation contribute to the initiation of periodontal disease. These make us consider that regulation of host defensive functions, epithelial barrier and neutrophil activity, may become novel preventive methods for periodontal inflammation. Based on this concept, we have found that several agents regulate the barrier function of gingival epithelial cells and suppress the accumulation of neutrophils in the gingival epithelium. We herein introduce the actions of irsogladine maleate, azithromycin, amphotericin B, and Houttuynia cordata (dokudami in Japanese), which is commonly used in traditional medicine, on the epithelial barrier and neutrophil migration in gingival epithelial cells in vivo and in vitro , in order to provide support for the clinical application of these agents to the prevention of periodontal inflammation.

Redox regulation of cell proliferation: Bioinformatics and redox proteomics approaches to identify redox-sensitive cell cycle regulators.

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Foyer, Christine H; Wilson, Michael H; Wright, Megan H

2018-03-29

Plant stem cells are the foundation of plant growth and development. The balance of quiescence and division is highly regulated, while ensuring that proliferating cells are protected from the adverse effects of environment fluctuations that may damage the genome. Redox regulation is important in both the activation of proliferation and arrest of the cell cycle upon perception of environmental stress. Within this context, reactive oxygen species serve as 'pro-life' signals with positive roles in the regulation of the cell cycle and survival. However, very little is known about the metabolic mechanisms and redox-sensitive proteins that influence cell cycle progression. We have identified cysteine residues on known cell cycle regulators in Arabidopsis that are potentially accessible, and could play a role in redox regulation, based on secondary structure and solvent accessibility likelihoods for each protein. We propose that redox regulation may function alongside other known posttranslational modifications to control the functions of core cell cycle regulators such as the retinoblastoma protein. Since our current understanding of how redox regulation is involved in cell cycle control is hindered by a lack of knowledge regarding both which residues are important and how modification of those residues alters protein function, we discuss how critical redox modifications can be mapped at the molecular level. Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.

Podoplanin regulates mammary stem cell function and tumorigenesis by potentiating Wnt/β-catenin signaling.

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Bresson, Laura; Faraldo, Marisa M; Di-Cicco, Amandine; Quintanilla, Miguel; Glukhova, Marina A; Deugnier, Marie-Ange

2018-02-21

Stem cells (SCs) drive mammary development, giving rise postnatally to an epithelial bilayer composed of luminal and basal myoepithelial cells. Dysregulation of SCs is thought to be at the origin of certain breast cancers; however, the molecular identity of SCs and the factors regulating their function remain poorly defined. We identified the transmembrane protein podoplanin (Pdpn) as a specific marker of the basal compartment, including multipotent SCs, and found Pdpn localized at the basal-luminal interface. Embryonic deletion of Pdpn targeted to basal cells diminished basal and luminal SC activity and affected the expression of several Wnt/β-catenin signaling components in basal cells. Moreover, Pdpn loss attenuated mammary tumor formation in a mouse model of β-catenin-induced breast cancer, limiting tumor-initiating cell expansion and promoting molecular features associated with mesenchymal-to-epithelial cell transition. In line with the loss-of-function data, we demonstrated that mechanistically Pdpn enhances Wnt/β-catenin signaling in mammary basal cells. Overall, this study uncovers a role for Pdpn in mammary SC function and, importantly, identifies Pdpn as a new regulator of Wnt/β-catenin signaling, a key pathway in mammary development and tumorigenesis. © 2018. Published by The Company of Biologists Ltd.

The regulation of function, growth and survival of GLP-1-producing L-cells

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Kuhre, Rune Ehrenreich; Holst, Jens Juul; Kappe, Camilla

2016-01-01

that regulate the growth, survival and function of these cells are largely unknown. We recently showed that prolonged exposure to high concentrations of the fatty acid palmitate induced lipotoxic effects, similar to those operative in insulin-producing cells, in an in vitro model of GLP-1-producing cells...... absorption and disposal, as well as cell proliferation and survival. In Type 2 Diabetes (T2D) reduced plasma levels of GLP-1 have been observed, and plasma levels of GLP-1, as well as reduced numbers of GLP-1 producing cells, have been correlated to obesity and insulin resistance. Increasing endogenous...... secretion of GLP-1 by selective targeting of the molecular mechanisms regulating secretion from the L-cell has been the focus of much recent research. An additional and promising strategy for enhancing endogenous secretion may be to increase the L-cell mass in the intestinal epithelium, but the mechanisms...

Neuron-NG2 Cell Synapses: Novel Functions for Regulating NG2 Cell Proliferation and Differentiation

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Qian-Kun Yang

2013-01-01

Full Text Available NG2 cells are a population of CNS cells that are distinct from neurons, mature oligodendrocytes, astrocytes, and microglia. These cells can be identified by their NG2 proteoglycan expression. NG2 cells have a highly branched morphology, with abundant processes radiating from the cell body, and express a complex set of voltage-gated channels, AMPA/kainate, and GABA receptors. Neurons notably form classical and nonclassical synapses with NG2 cells, which have varied characteristics and functions. Neuron-NG2 cell synapses could fine-tune NG2 cell activities, including the NG2 cell cycle, differentiation, migration, and myelination, and may be a novel potential therapeutic target for NG2 cell-related diseases, such as hypoxia-ischemia injury and periventricular leukomalacia. Furthermore, neuron-NG2 cell synapses may be correlated with the plasticity of CNS in adulthood with the synaptic contacts passing onto their progenies during proliferation, and synaptic contacts decrease rapidly upon NG2 cell differentiation. In this review, we highlight the characteristics of classical and nonclassical neuron-NG2 cell synapses, the potential functions, and the fate of synaptic contacts during proliferation and differentiation, with the emphasis on the regulation of the NG2 cell cycle by neuron-NG2 cell synapses and their potential underlying mechanisms.

miRNA-mediated functional changes through co-regulating function related genes.

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Jie He

Full Text Available BACKGROUND: MicroRNAs play important roles in various biological processes involving fairly complex mechanism. Analysis of genome-wide miRNA microarray demonstrate that a single miRNA can regulate hundreds of genes, but the regulative extent on most individual genes is surprisingly mild so that it is difficult to understand how a miRNA provokes detectable functional changes with such mild regulation. RESULTS: To explore the internal mechanism of miRNA-mediated regulation, we re-analyzed the data collected from genome-wide miRNA microarray with bioinformatics assay, and found that the transfection of miR-181b and miR-34a in Hela and HCT-116 tumor cells regulated large numbers of genes, among which, the genes related to cell growth and cell death demonstrated high Enrichment scores, suggesting that these miRNAs may be important in cell growth and cell death. MiR-181b induced changes in protein expression of most genes that were seemingly related to enhancing cell growth and decreasing cell death, while miR-34a mediated contrary changes of gene expression. Cell growth assays further confirmed this finding. In further study on miR-20b-mediated osteogenesis in hMSCs, miR-20b was found to enhance osteogenesis by activating BMPs/Runx2 signaling pathway in several stages by co-repressing of PPARγ, Bambi and Crim1. CONCLUSIONS: With its multi-target characteristics, miR-181b, miR-34a and miR-20b provoked detectable functional changes by co-regulating functionally-related gene groups or several genes in the same signaling pathway, and thus mild regulation from individual miRNA targeting genes could have contributed to an additive effect. This might also be one of the modes of miRNA-mediated gene regulation.

Molecular regulation of dendritic cell development and function in homeostasis, inflammation, and cancer.

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Chrisikos, Taylor T; Zhou, Yifan; Slone, Natalie; Babcock, Rachel; Watowich, Stephanie S; Li, Haiyan S

2018-03-14

Dendritic cells (DCs) are the principal antigen-presenting cells of the immune system and play key roles in controlling immune tolerance and activation. As such, DCs are chief mediators of tumor immunity. DCs can regulate tolerogenic immune responses that facilitate unchecked tumor growth. Importantly, however, DCs also mediate immune-stimulatory activity that restrains tumor progression. For instance, emerging evidence indicates the cDC1 subset has important functions in delivering tumor antigens to lymph nodes and inducing antigen-specific lymphocyte responses to tumors. Moreover, DCs control specific therapeutic responses in cancer including those resulting from immune checkpoint blockade. DC generation and function is influenced profoundly by cytokines, as well as their intracellular signaling proteins including STAT transcription factors. Regardless, our understanding of DC regulation in the cytokine-rich tumor microenvironment is still developing and must be better defined to advance cancer treatment. Here, we review literature focused on the molecular control of DCs, with a particular emphasis on cytokine- and STAT-mediated DC regulation. In addition, we highlight recent studies that delineate the importance of DCs in anti-tumor immunity and immune therapy, with the overall goal of improving knowledge of tumor-associated factors and intrinsic DC signaling cascades that influence DC function in cancer. Copyright © 2018 Elsevier Ltd. All rights reserved.

B cells promote inflammation in obesity and type 2 diabetes through regulation of T-cell function and an inflammatory cytokine profile.

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DeFuria, Jason; Belkina, Anna C; Jagannathan-Bogdan, Madhumita; Snyder-Cappione, Jennifer; Carr, Jordan David; Nersesova, Yanina R; Markham, Douglas; Strissel, Katherine J; Watkins, Amanda A; Zhu, Min; Allen, Jessica; Bouchard, Jacqueline; Toraldo, Gianluca; Jasuja, Ravi; Obin, Martin S; McDonnell, Marie E; Apovian, Caroline; Denis, Gerald V; Nikolajczyk, Barbara S

2013-03-26

Patients with type 2 diabetes (T2D) have disease-associated changes in B-cell function, but the role these changes play in disease pathogenesis is not well established. Data herein show B cells from obese mice produce a proinflammatory cytokine profile compared with B cells from lean mice. Complementary in vivo studies show that obese B cell-null mice have decreased systemic inflammation, inflammatory B- and T-cell cytokines, adipose tissue inflammation, and insulin resistance (IR) compared with obese WT mice. Reduced inflammation in obese/insulin resistant B cell-null mice associates with an increased percentage of anti-inflammatory regulatory T cells (Tregs). This increase contrasts with the sharply decreased percentage of Tregs in obese compared with lean WT mice and suggests that B cells may be critical regulators of T-cell functions previously shown to play important roles in IR. We demonstrate that B cells from T2D (but not non-T2D) subjects support proinflammatory T-cell function in obesity/T2D through contact-dependent mechanisms. In contrast, human monocytes increase proinflammatory T-cell cytokines in both T2D and non-T2D analyses. These data support the conclusion that B cells are critical regulators of inflammation in T2D due to their direct ability to promote proinflammatory T-cell function and secrete a proinflammatory cytokine profile. Thus, B cells are potential therapeutic targets for T2D.

Eps8 regulates hair bundle length and functional maturation of mammalian auditory hair cells.

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Valeria Zampini

2011-04-01

Full Text Available Hair cells of the mammalian cochlea are specialized for the dynamic coding of sound stimuli. The transduction of sound waves into electrical signals depends upon mechanosensitive hair bundles that project from the cell's apical surface. Each stereocilium within a hair bundle is composed of uniformly polarized and tightly packed actin filaments. Several stereociliary proteins have been shown to be associated with hair bundle development and function and are known to cause deafness in mice and humans when mutated. The growth of the stereociliar actin core is dynamically regulated at the actin filament barbed ends in the stereociliary tip. We show that Eps8, a protein with actin binding, bundling, and barbed-end capping activities in other systems, is a novel component of the hair bundle. Eps8 is localized predominantly at the tip of the stereocilia and is essential for their normal elongation and function. Moreover, we have found that Eps8 knockout mice are profoundly deaf and that IHCs, but not OHCs, fail to mature into fully functional sensory receptors. We propose that Eps8 directly regulates stereocilia growth in hair cells and also plays a crucial role in the physiological maturation of mammalian cochlear IHCs. Together, our results indicate that Eps8 is critical in coordinating the development and functionality of mammalian auditory hair cells.

Eps8 regulates hair bundle length and functional maturation of mammalian auditory hair cells.

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Zampini, Valeria; Rüttiger, Lukas; Johnson, Stuart L; Franz, Christoph; Furness, David N; Waldhaus, Jörg; Xiong, Hao; Hackney, Carole M; Holley, Matthew C; Offenhauser, Nina; Di Fiore, Pier Paolo; Knipper, Marlies; Masetto, Sergio; Marcotti, Walter

2011-04-01

Hair cells of the mammalian cochlea are specialized for the dynamic coding of sound stimuli. The transduction of sound waves into electrical signals depends upon mechanosensitive hair bundles that project from the cell's apical surface. Each stereocilium within a hair bundle is composed of uniformly polarized and tightly packed actin filaments. Several stereociliary proteins have been shown to be associated with hair bundle development and function and are known to cause deafness in mice and humans when mutated. The growth of the stereociliar actin core is dynamically regulated at the actin filament barbed ends in the stereociliary tip. We show that Eps8, a protein with actin binding, bundling, and barbed-end capping activities in other systems, is a novel component of the hair bundle. Eps8 is localized predominantly at the tip of the stereocilia and is essential for their normal elongation and function. Moreover, we have found that Eps8 knockout mice are profoundly deaf and that IHCs, but not OHCs, fail to mature into fully functional sensory receptors. We propose that Eps8 directly regulates stereocilia growth in hair cells and also plays a crucial role in the physiological maturation of mammalian cochlear IHCs. Together, our results indicate that Eps8 is critical in coordinating the development and functionality of mammalian auditory hair cells.

Hepatocyte growth factor regulated tyrosine kinase substrate in the peripheral development and function of B-cells

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Nagata, Takayuki; Murata, Kazuko; Murata, Ryo; Sun, Shu-lan; Saito, Yutaro; Yamaga, Shuhei; Tanaka, Nobuyuki; Tamai, Keiichi; Moriya, Kunihiko; Kasai, Noriyuki; Sugamura, Kazuo; Ishii, Naoto

2014-01-01

Highlights: •ESCRT-0 protein regulates the development of peripheral B-cells. •BCR expression on cell surface should be controlled by the endosomal-sorting system. •Hrs plays important roles in responsiveness to Ag stimulation in B lymphocytes. -- Abstract: Hepatocyte growth factor (HGF)-regulated tyrosine kinase substrate (Hrs) is a vesicular sorting protein that functions as one of the endosomal-sorting proteins required for transport (ESCRT). Hrs, which binds to ubiquitinated proteins through its ubiquitin-interacting motif (UIM), contributes to the lysosomal transport and degradation of ubiquitinated membrane proteins. However, little is known about the relationship between B-cell functions and ESCRT proteins in vivo. Here we examined the immunological roles of Hrs in B-cell development and functions using B-cell-specific Hrs-deficient (Hrs flox/flox ;mb1 cre/+ :Hrs-cKO) mice, which were generated using a cre-LoxP recombination system. Hrs deficiency in B-cells significantly reduced T-cell-dependent antibody production in vivo and impaired the proliferation of B-cells treated in vitro with an anti-IgM monoclonal antibody but not with LPS. Although early development of B-cells in the bone marrow was normal in Hrs-cKO mice, there was a significant decrease in the number of the peripheral transitional B-cells and marginal zone B-cells in the spleen of Hrs-cKO mice. These results indicate that Hrs plays important roles during peripheral development and physiological functions of B lymphocytes

Hepatocyte growth factor regulated tyrosine kinase substrate in the peripheral development and function of B-cells

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Nagata, Takayuki [Department of Pharmacy, Iwaki Meisei University, 5-5-1 Chuodai Iino, Iwaki, Fukushima 970-8551 (Japan); Department of Microbiology and Immunology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575 (Japan); Murata, Kazuko, E-mail: murata-k@iwakimu.ac.jp [Department of Pharmacy, Iwaki Meisei University, 5-5-1 Chuodai Iino, Iwaki, Fukushima 970-8551 (Japan); Murata, Ryo [Department of Pharmacy, Iwaki Meisei University, 5-5-1 Chuodai Iino, Iwaki, Fukushima 970-8551 (Japan); Sun, Shu-lan [Department of Microbiology and Immunology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575 (Japan); Saito, Yutaro; Yamaga, Shuhei [Department of Pharmacy, Iwaki Meisei University, 5-5-1 Chuodai Iino, Iwaki, Fukushima 970-8551 (Japan); Tanaka, Nobuyuki; Tamai, Keiichi [Division of Immunology, Miyagi Cancer Research Institute, 47-1 Nodayama, Medeshima-Shiode, Natori 981-1293 (Japan); Moriya, Kunihiko [Department of Pediatrics, Tohoku University School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8575 (Japan); Kasai, Noriyuki [Institute for Animal Experimentation, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575 (Japan); Sugamura, Kazuo [Division of Immunology, Miyagi Cancer Research Institute, 47-1 Nodayama, Medeshima-Shiode, Natori 981-1293 (Japan); Ishii, Naoto [Department of Microbiology and Immunology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575 (Japan)

2014-01-10

Highlights: •ESCRT-0 protein regulates the development of peripheral B-cells. •BCR expression on cell surface should be controlled by the endosomal-sorting system. •Hrs plays important roles in responsiveness to Ag stimulation in B lymphocytes. -- Abstract: Hepatocyte growth factor (HGF)-regulated tyrosine kinase substrate (Hrs) is a vesicular sorting protein that functions as one of the endosomal-sorting proteins required for transport (ESCRT). Hrs, which binds to ubiquitinated proteins through its ubiquitin-interacting motif (UIM), contributes to the lysosomal transport and degradation of ubiquitinated membrane proteins. However, little is known about the relationship between B-cell functions and ESCRT proteins in vivo. Here we examined the immunological roles of Hrs in B-cell development and functions using B-cell-specific Hrs-deficient (Hrs{sup flox/flox};mb1{sup cre/+}:Hrs-cKO) mice, which were generated using a cre-LoxP recombination system. Hrs deficiency in B-cells significantly reduced T-cell-dependent antibody production in vivo and impaired the proliferation of B-cells treated in vitro with an anti-IgM monoclonal antibody but not with LPS. Although early development of B-cells in the bone marrow was normal in Hrs-cKO mice, there was a significant decrease in the number of the peripheral transitional B-cells and marginal zone B-cells in the spleen of Hrs-cKO mice. These results indicate that Hrs plays important roles during peripheral development and physiological functions of B lymphocytes.

Neurotrophin Receptor p75NTR Regulates Immune Function of Plasmacytoid Dendritic Cells.

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Bandoła, Joanna; Richter, Cornelia; Ryser, Martin; Jamal, Arshad; Ashton, Michelle P; von Bonin, Malte; Kuhn, Matthias; Dorschner, Benjamin; Alexopoulou, Dimitra; Navratiel, Katrin; Roeder, Ingo; Dahl, Andreas; Hedrich, Christian M; Bonifacio, Ezio; Brenner, Sebastian; Thieme, Sebastian

2017-01-01

Plasmacytoid dendritic cells (pDCs) regulate innate and adaptive immunity. Neurotrophins and their receptors control the function of neuronal tissue. In addition, they have been demonstrated to be part of the immune response but little is known about the effector immune cells involved. We report, for the first time, the expression and immune-regulatory function of the low affinity neurotrophin receptor p75 neurotrophin receptor (p75NTR) by the antigen-presenting pDCs, mediated by toll-like receptor (TLR) 9 activation and differential phosphorylation of interferon regulatory factor 3 and 7. The modulation of p75NTR on pDCs significantly influences disease progression of asthma in an ovalbumin-induced mouse model mediated by the TLR9 signaling pathway. p75NTR activation of pDCs from patients with asthma increased allergen-specific T cell proliferation and cytokine secretion in nerve growth factor concentration-dependent manner. Further, p75NTR activation of pDCs delayed the onset of autoimmune diabetes in RIP-CD80GP mice and aggravated graft-versus-host disease in a xenotransplantation model. Thus, p75NTR signaling on pDCs constitutes a new and critical mechanism connecting neurotrophin signaling and immune response regulation with great therapeutic potential for a variety of immune disorders.

Neurotrophin Receptor p75NTR Regulates Immune Function of Plasmacytoid Dendritic Cells

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Joanna Bandoła

2017-08-01

Full Text Available Plasmacytoid dendritic cells (pDCs regulate innate and adaptive immunity. Neurotrophins and their receptors control the function of neuronal tissue. In addition, they have been demonstrated to be part of the immune response but little is known about the effector immune cells involved. We report, for the first time, the expression and immune-regulatory function of the low affinity neurotrophin receptor p75 neurotrophin receptor (p75NTR by the antigen-presenting pDCs, mediated by toll-like receptor (TLR 9 activation and differential phosphorylation of interferon regulatory factor 3 and 7. The modulation of p75NTR on pDCs significantly influences disease progression of asthma in an ovalbumin-induced mouse model mediated by the TLR9 signaling pathway. p75NTR activation of pDCs from patients with asthma increased allergen-specific T cell proliferation and cytokine secretion in nerve growth factor concentration-dependent manner. Further, p75NTR activation of pDCs delayed the onset of autoimmune diabetes in RIP-CD80GP mice and aggravated graft-versus-host disease in a xenotransplantation model. Thus, p75NTR signaling on pDCs constitutes a new and critical mechanism connecting neurotrophin signaling and immune response regulation with great therapeutic potential for a variety of immune disorders.

Phosphorylation regulates human T-cell leukemia virus type 1 Rex function

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Ward Michael

2009-11-01

Full Text Available Abstract Background Human T-cell leukemia virus type 1 (HTLV-1 is a pathogenic complex deltaretrovirus, which is the causative agent of adult T-cell leukemia/lymphoma (ATL and HTLV-1-associated myelopathy/tropical spastic paraparesis. In addition to the structural and enzymatic viral gene products, HTLV-1 encodes the positive regulatory proteins Tax and Rex along with viral accessory proteins. Tax and Rex proteins orchestrate the timely expression of viral genes important in viral replication and cellular transformation. Rex is a nucleolar-localizing shuttling protein that acts post-transcriptionally by binding and facilitating the export of the unspliced and incompletely spliced viral mRNAs from the nucleus to the cytoplasm. HTLV-1 Rex (Rex-1 is a phosphoprotein and general protein kinase inhibition correlates with reduced function. Therefore, it has been proposed that Rex-1 function may be regulated through site-specific phosphorylation. Results We conducted a phosphoryl mapping of Rex-1 over-expressed in transfected 293 T cells using a combination of affinity purification and liquid chromatography tandem mass spectrometry. We achieved 100% physical coverage of the Rex-1 polypeptide and identified five novel phosphorylation sites at Thr-22, Ser-36, Thr-37, Ser-97, and Ser-106. We also confirmed evidence of two previously identified residues, Ser-70 and Thr-174, but found no evidence of phosphorylation at Ser-177. The functional significance of these phosphorylation events was evaluated using a Rex reporter assay and site-directed mutational analysis. Our results indicate that phosphorylation at Ser-97 and Thr-174 is critical for Rex-1 function. Conclusion We have mapped completely the site-specific phosphorylation of Rex-1 identifying a total of seven residues; Thr-22, Ser-36, Thr-37, Ser-70, Ser-97, Ser-106, and Thr-174. Overall, this work is the first to completely map the phosphorylation sites in Rex-1 and provides important insight into

ZFP521 regulates murine hematopoietic stem cell function and facilitates MLL-AF9 leukemogenesis in mouse and human cells.

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Garrison, Brian S; Rybak, Adrian P; Beerman, Isabel; Heesters, Balthasar; Mercier, Francois E; Scadden, David T; Bryder, David; Baron, Roland; Rossi, Derrick J

2017-08-03

The concept that tumor-initiating cells can co-opt the self-renewal program of endogenous stem cells as a means of enforcing their unlimited proliferative potential is widely accepted, yet identification of specific factors that regulate self-renewal of normal and cancer stem cells remains limited. Using a comparative transcriptomic approach, we identify ZNF521 / Zfp521 as a conserved hematopoietic stem cell (HSC)-enriched transcription factor in human and murine hematopoiesis whose function in HSC biology remains elusive. Competitive serial transplantation assays using Zfp521 -deficient mice revealed that ZFP521 regulates HSC self-renewal and differentiation. In contrast, ectopic expression of ZFP521 in HSCs led to a robust maintenance of progenitor activity in vitro. Transcriptional analysis of human acute myeloid leukemia (AML) patient samples revealed that ZNF521 is highly and specifically upregulated in AMLs with MLL translocations. Using an MLL-AF9 murine leukemia model and serial transplantation studies, we show that ZFP521 is not required for leukemogenesis, although its absence leads to a significant delay in leukemia onset. Furthermore, knockdown of ZNF521 reduced proliferation in human leukemia cell lines possessing MLL-AF9 translocations. Taken together, these results identify ZNF521/ZFP521 as a critical regulator of HSC function, which facilitates MLL-AF9-mediated leukemic disease in mice.

Human neural progenitors express functional lysophospholipid receptors that regulate cell growth and morphology

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Callihan Phillip

2008-12-01

Full Text Available Abstract Background Lysophospholipids regulate the morphology and growth of neurons, neural cell lines, and neural progenitors. A stable human neural progenitor cell line is not currently available in which to study the role of lysophospholipids in human neural development. We recently established a stable, adherent human embryonic stem cell-derived neuroepithelial (hES-NEP cell line which recapitulates morphological and phenotypic features of neural progenitor cells isolated from fetal tissue. The goal of this study was to determine if hES-NEP cells express functional lysophospholipid receptors, and if activation of these receptors mediates cellular responses critical for neural development. Results Our results demonstrate that Lysophosphatidic Acid (LPA and Sphingosine-1-phosphate (S1P receptors are functionally expressed in hES-NEP cells and are coupled to multiple cellular signaling pathways. We have shown that transcript levels for S1P1 receptor increased significantly in the transition from embryonic stem cell to hES-NEP. hES-NEP cells express LPA and S1P receptors coupled to Gi/o G-proteins that inhibit adenylyl cyclase and to Gq-like phospholipase C activity. LPA and S1P also induce p44/42 ERK MAP kinase phosphorylation in these cells and stimulate cell proliferation via Gi/o coupled receptors in an Epidermal Growth Factor Receptor (EGFR- and ERK-dependent pathway. In contrast, LPA and S1P stimulate transient cell rounding and aggregation that is independent of EGFR and ERK, but dependent on the Rho effector p160 ROCK. Conclusion Thus, lysophospholipids regulate neural progenitor growth and morphology through distinct mechanisms. These findings establish human ES cell-derived NEP cells as a model system for studying the role of lysophospholipids in neural progenitors.

Piezo type mechanosensitive ion channel component 1 functions as a regulator of the cell fate determination of mesenchymal stem cells.

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Sugimoto, Asuna; Miyazaki, Aya; Kawarabayashi, Keita; Shono, Masayuki; Akazawa, Yuki; Hasegawa, Tomokazu; Ueda-Yamaguchi, Kimiko; Kitamura, Takamasa; Yoshizaki, Keigo; Fukumoto, Satoshi; Iwamoto, Tsutomu

2017-12-18

The extracellular environment regulates the dynamic behaviors of cells. However, the effects of hydrostatic pressure (HP) on cell fate determination of mesenchymal stem cells (MSCs) are not clearly understood. Here, we established a cell culture chamber to control HP. Using this system, we found that the promotion of osteogenic differentiation by HP is depend on bone morphogenetic protein 2 (BMP2) expression regulated by Piezo type mechanosensitive ion channel component 1 (PIEZO1) in MSCs. The PIEZO1 was expressed and induced after HP loading in primary MSCs and MSC lines, UE7T-13 and SDP11. HP and Yoda1, an activator of PIEZO1, promoted BMP2 expression and osteoblast differentiation, whereas inhibits adipocyte differentiation. Conversely, PIEZO1 inhibition reduced osteoblast differentiation and BMP2 expression. Furthermore, Blocking of BMP2 function by noggin inhibits HP induced osteogenic maker genes expression. In addition, in an in vivo model of medaka with HP loading, HP promoted caudal fin ray development whereas inhibition of piezo1 using GsMTx4 suppressed its development. Thus, our results suggested that PIEZO1 is responsible for HP and could functions as a factor for cell fate determination of MSCs by regulating BMP2 expression.

Cyclic guanosine monophosphate in the regulation of the cell function

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Małgorzata Zbrojkiewicz

2016-12-01

Full Text Available Intracellular concentration of cGMP depends on the activity of guanylate cyclase, responsible for its synthesis, on the activity of cyclic nucleotide degrading enzymes - phosphodiesterases (PDEs. There are two forms of guanylate cyclase: the membrane-bound cyclase and the soluble form. The physiological activators of the membrane guanylate cyclase are natriuretic peptides (NPs, and of the cytosolic guanylate cyclase - nitric oxide (NO and carbon monoxide (CO. Intracellular cGMP signaling pathways arise from its direct effect on the activity of G protein kinases, phosphodiesterases and cyclic nucleotide dependent cation channels. It has been shown in recent years that cGMP can also affect other signal pathways in cell signaling activity involving Wnt proteins and sex hormones. The increased interest in the research on the role of cGMP, resulted also in the discovery of its role in the regulation of phototransduction in the eye, neurotransmission, calcium homeostasis, platelet aggregation, heartbeat, bone remodeling, lipid metabolism and the activity of the cation channels. Better understanding of the mechanisms of action of cGMP in the regulation of cell function can create new opportunities for the cGMP affecting drugs use in the pharmacotherapy.

Nicotinic receptors and functional regulation of GABA cell microcircuitry in bipolar disorder and schizophrenia.

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Benes, Francine M

2012-01-01

Studies of the hippocampus in postmortem brains from patients with schizophrenia and bipolar disorder have provided evidence for a defect of GABAergic interneurons. Significant decreases in the expression of GAD67, a marker for GABA cell function, have been found repeatedly in several different brain regions that include the hippocampus. In this region, nicotinic receptors are thought to play an important role in modulating the activity of GABAergic interneurons by influences of excitatory cholinergic afferents on their activity. In bipolar disorder, this influence appears to be particularly prominent in the stratum oriens of sectors CA3/2 and CA1, two sites where these cells constitute the exclusive neuronal cell type. In sector CA3/2, this layer receives a robust excitatory projection from the basolateral amygdala (BLA) and this is thought to play a central role in regulating GABA cells at this locus. Using laser microdissection, recent studies have focused selectively on these two layers and their associated GABA cells using microarray technology. The results have provided support for the idea that nicotinic cholinergic receptors play a particularly important role in regulating the activity of GABA neurons at these loci by regulating the progression of cell cycle and the repair of damaged DNA. In bipolar disorder, there is a prominent reduction in the expression of mRNAs for several different nicotinic subunit isoforms. These decreases could reflect a diminished influence of this receptor system on these GABA cells, particularly in sector CA3/2 where a preponderance of abnormalities have been observed in postmortem studies. In patients with bipolar disorder, excitatory nicotinic cholinergic fibers from the medial septum may converge with glutamatergic fibers from the BLA on GABAergic interneurons in the stratum oriens of CA3/2 and result in disturbances of their genomic and functional integrity, ones that may induce disruptions of the integration of

Cancers take their Toll--the function and regulation of Toll-like receptors in cancer cells

DEFF Research Database (Denmark)

Chen, R; Alvero, A B; Silasi, D-A

2008-01-01

proliferation, would also be key factors in regulating and enhancing cancer progression. The TLR pathways, which play a critical role in tissue repair, are also key regulators in cancer progression as well as chemoresistance. TLRs serve as cell surface sensors that can initiate pathways leading to proliferation......Cancer could be deemed as an abnormal and uncontrolled tissue repair process. Therefore, it would not be surprising that factors that function in the tissue repair process, such as cytokines, chemokines, growth factors and Toll-like receptor (TLR) ligands, as well as growth signals for compensatory...... and chemoresistance; as well as mediators that are able to regulate the infiltrating immune cells to provide further support for cancer progression....

Ion Channels Involved in Cell Volume Regulation

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Hoffmann, Else Kay

2011-01-01

regulatory ion channels involved, and the mechanisms (cellular signalling pathways) that regulate these channels. Finally, I shall also briefly review current investigations in these two cell lines that focuses on how changes in cell volume can regulate cell functions such as cell migration, proliferation......This mini review outlines studies of cell volume regulation in two closely related mammalian cell lines: nonadherent Ehrlich ascites tumour cells (EATC) and adherent Ehrlich Lettre ascites (ELA) cells. Focus is on the regulatory volume decrease (RVD) that occurs after cell swelling, the volume...

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

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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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cell Cycle Regulation of Stem Cells by MicroRNAs.

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Mens, Michelle M J; Ghanbari, Mohsen

2018-06-01

MicroRNAs (miRNAs) are a class of small non-coding RNA molecules involved in the regulation of gene expression. They are involved in the fine-tuning of fundamental biological processes such as proliferation, differentiation, survival and apoptosis in many cell types. Emerging evidence suggests that miRNAs regulate critical pathways involved in stem cell function. Several miRNAs have been suggested to target transcripts that directly or indirectly coordinate the cell cycle progression of stem cells. Moreover, previous studies have shown that altered expression levels of miRNAs can contribute to pathological conditions, such as cancer, due to the loss of cell cycle regulation. However, the precise mechanism underlying miRNA-mediated regulation of cell cycle in stem cells is still incompletely understood. In this review, we discuss current knowledge of miRNAs regulatory role in cell cycle progression of stem cells. We describe how specific miRNAs may control cell cycle associated molecules and checkpoints in embryonic, somatic and cancer stem cells. We further outline how these miRNAs could be regulated to influence cell cycle progression in stem cells as a potential clinical application.

Regulation of Hematopoietic Cell Development and Function Through Phosphoinositides

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Mila Elich

2018-05-01

Full Text Available One of the most paramount receptor-induced signal transduction mechanisms in hematopoietic cells is production of the lipid second messenger phosphatidylinositol(3,4,5trisphosphate (PIP3 by class I phosphoinositide 3 kinases (PI3K. Defective PIP3 signaling impairs almost every aspect of hematopoiesis, including T cell development and function. Limiting PIP3 signaling is particularly important, because excessive PIP3 function in lymphocytes can transform them and cause blood cancers. Here, we review the key functions of PIP3 and related phosphoinositides in hematopoietic cells, with a special focus on those mechanisms dampening PIP3 production, turnover, or function. Recent studies have shown that beyond “canonical” turnover by the PIP3 phosphatases and tumor suppressors phosphatase and tensin homolog (PTEN and SH2 domain-containing inositol-5-phosphatase-1 (SHIP-1/2, PIP3 function in hematopoietic cells can also be dampened through antagonism with the soluble PIP3 analogs inositol(1,3,4,5tetrakisphosphate (IP4 and inositol-heptakisphosphate (IP7. Other evidence suggests that IP4 can promote PIP3 function in thymocytes. Moreover, IP4 or the kinases producing it limit store-operated Ca2+ entry through Orai channels in B cells, T cells, and neutrophils to control cell survival and function. We discuss current models for how soluble inositol phosphates can have such diverse functions and can govern as distinct processes as hematopoietic stem cell homeostasis, neutrophil macrophage and NK cell function, and development and function of B cells and T cells. Finally, we will review the pathological consequences of dysregulated IP4 activity in immune cells and highlight contributions of impaired inositol phosphate functions in disorders such as Kawasaki disease, common variable immunodeficiency, or blood cancer.

Osteomacs interact with megakaryocytes and osteoblasts to regulate murine hematopoietic stem cell function.

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Mohamad, Safa F; Xu, Linlin; Ghosh, Joydeep; Childress, Paul J; Abeysekera, Irushi; Himes, Evan R; Wu, Hao; Alvarez, Marta B; Davis, Korbin M; Aguilar-Perez, Alexandra; Hong, Jung Min; Bruzzaniti, Angela; Kacena, Melissa A; Srour, Edward F

2017-12-12

Networking between hematopoietic stem cells (HSCs) and cells of the hematopoietic niche is critical for stem cell function and maintenance of the stem cell pool. We characterized calvariae-resident osteomacs (OMs) and their interaction with megakaryocytes to sustain HSC function and identified distinguishing properties between OMs and bone marrow (BM)-derived macrophages. OMs, identified as CD45 + F4/80 + cells, were easily detectable (3%-5%) in neonatal calvarial cells. Coculture of neonatal calvarial cells with megakaryocytes for 7 days increased OM three- to sixfold, demonstrating that megakaryocytes regulate OM proliferation. OMs were required for the hematopoiesis-enhancing activity of osteoblasts, and this activity was augmented by megakaryocytes. Serial transplantation demonstrated that HSC repopulating potential was best maintained by in vitro cultures containing osteoblasts, OMs, and megakaryocytes. With or without megakaryocytes, BM-derived macrophages were unable to functionally substitute for neonatal calvarial cell-associated OMs. In addition, OMs differentiated into multinucleated, tartrate resistant acid phosphatase-positive osteoclasts capable of bone resorption. Nine-color flow cytometric analysis revealed that although BM-derived macrophages and OMs share many cell surface phenotypic similarities (CD45, F4/80, CD68, CD11b, Mac2, and Gr-1), only a subgroup of OMs coexpressed M-CSFR and CD166, thus providing a unique profile for OMs. CD169 was expressed by both OMs and BM-derived macrophages and therefore was not a distinguishing marker between these 2 cell types. These results demonstrate that OMs support HSC function and illustrate that megakaryocytes significantly augment the synergistic activity of osteoblasts and OMs. Furthermore, this report establishes for the first time that the crosstalk between OMs, osteoblasts, and megakaryocytes is a novel network supporting HSC function.

Structural-Functional Organization of the Eukaryotic Cell Nucleus and Transcription Regulation: Introduction to This Special Issue of Biochemistry (Moscow).

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Razin, S V

2018-04-01

This issue of Biochemistry (Moscow) is devoted to the cell nucleus and mechanisms of transcription regulation. Over the years, biochemical processes in the cell nucleus have been studied in isolation, outside the context of their spatial organization. Now it is clear that segregation of functional processes within a compartmentalized cell nucleus is very important for the implementation of basic genetic processes. The functional compartmentalization of the cell nucleus is closely related to the spatial organization of the genome, which in turn plays a key role in the operation of epigenetic mechanisms. In this issue of Biochemistry (Moscow), we present a selection of review articles covering the functional architecture of the eukaryotic cell nucleus, the mechanisms of genome folding, the role of stochastic processes in establishing 3D architecture of the genome, and the impact of genome spatial organization on transcription regulation.

The functional role for condensin in the regulation of chromosomal organization during the cell cycle.

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Kagami, Yuya; Yoshida, Kiyotsugu

2016-12-01

In all organisms, the control of cell cycle progression is a fundamental process that is essential for cell growth, development, and survival. Through each cell cycle phase, the regulation of chromatin organization is essential for natural cell proliferation and maintaining cellular homeostasis. During mitosis, the chromatin morphology is dramatically changed to have a "thread-like" shape and the condensed chromosomes are segregated equally into two daughter cells. Disruption of the mitotic chromosome architecture physically impedes chromosomal behaviors, such as chromosome alignment and chromosome segregation; therefore, the proper mitotic chromosome structure is required to maintain chromosomal stability. Accumulating evidence has demonstrated that mitotic chromosome condensation is induced by condensin complexes. Moreover, recent studies have shown that condensin also modulates interphase chromatin and regulates gene expression. This review mainly focuses on the molecular mechanisms that condensin uses to exert its functions during the cell cycle progression. Moreover, we discuss the condensin-mediated chromosomal organization in cancer cells.

RASAL3, a novel hematopoietic RasGAP protein, regulates the number and functions of NKT cells.

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Saito, Suguru; Kawamura, Toshihiko; Higuchi, Masaya; Kobayashi, Takahiro; Yoshita-Takahashi, Manami; Yamazaki, Maya; Abe, Manabu; Sakimura, Kenji; Kanda, Yasuhiro; Kawamura, Hiroki; Jiang, Shuying; Naito, Makoto; Yoshizaki, Takumi; Takahashi, Masahiko; Fujii, Masahiro

2015-05-01

Ras GTPase-activating proteins negatively regulate the Ras/Erk signaling pathway, thereby playing crucial roles in the proliferation, function, and development of various types of cells. In this study, we identified a novel Ras GTPase-activating proteins protein, RASAL3, which is predominantly expressed in cells of hematopoietic lineages, including NKT, B, and T cells. We established systemic RASAL3-deficient mice, and the mice exhibited a severe decrease in NKT cells in the liver at 8 weeks of age. The treatment of RASAL3-deficient mice with α-GalCer, a specific agonist for NKT cells, induced liver damage, but the level was less severe than that in RASAL3-competent mice, and the attenuated liver damage was accompanied by a reduced production of interleukin-4 and interferon-γ from NKT cells. RASAL3-deficient NKT cells treated with α-GalCer in vitro presented augmented Erk phosphorylation, suggesting that there is dysregulated Ras signaling in the NKT cells of RASAL3-deficient mice. Taken together, these results suggest that RASAL3 plays an important role in the expansion and functions of NKT cells in the liver by negatively regulating Ras/Erk signaling, and might be a therapeutic target for NKT-associated diseases. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Regulation of NKG2D-Dependent NK Cell Functions: The Yin and the Yang of Receptor Endocytosis

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Rosa Molfetta

2017-08-01

Full Text Available Natural-killer receptor group 2, member D (NKG2D is a well characterized natural killer (NK cell activating receptor that recognizes several ligands poorly expressed on healthy cells but up-regulated upon stressing stimuli in the context of cancer or viral infection. Although NKG2D ligands represent danger signals that render target cells more susceptible to NK cell lysis, accumulating evidence demonstrates that persistent exposure to ligand-expressing cells causes the decrease of NKG2D surface expression leading to a functional impairment of NKG2D-dependent NK cell functions. Upon ligand binding, NKG2D is internalized from the plasma membrane and sorted to lysosomes for degradation. However, receptor endocytosis is not only a mechanism of receptor clearance from the cell surface, but is also required for the proper activation of signalling events leading to the functional program of NK cells. This review is aimed at providing a summary of current literature relevant to the molecular mechanisms leading to NKG2D down-modulation with particular emphasis given to the role of NKG2D endocytosis in both receptor degradation and signal propagation. Examples of chronic ligand-induced down-regulation of NK cell activating receptors other than NKG2D, including natural cytotoxicity receptors (NCRs, DNAX accessory molecule-1 (DNAM1 and CD16, will be also discussed.

Proximity-based differential single cell analysis of the niche to identify stem/progenitor cell regulators

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Silberstein, Lev; Goncalves, Kevin A; Kharchenko, Peter V; Turcotte, Raphael; Kfoury, Youmna; Mercier, Francois; Baryawno, Ninib; Severe, Nicolas; Bachand, Jacqueline; Spencer, Joel; Papazian, Ani; Lee, Dongjun; Chitteti, Brahmananda Reddy; Srour, Edward F; Hoggatt, Jonathan; Tate, Tiffany; Celso, Cristina Lo; Ono, Noriaki; Nutt, Stephen; Heino, Jyrki; Sipilä, Kalle; Shioda, Toshihiro; Osawa, Masatake; Lin, Charles P; Hu, Guo-fu; Scadden, David T

2016-01-01

SUMMARY Physiological stem cell function is regulated by secreted factors produced by niche cells. In this study, we describe an unbiased approach based on differential single-cell gene expression analysis of mesenchymal osteolineage cells close to and further removed from hematopoietic stem/progenitor cells to identify candidate niche factors. Mesenchymal cells displayed distinct molecular profiles based on their relative location. Amongst the genes which were preferentially expressed in proximal cells, we functionally examined three secreted or cell surface molecules not previously connected to HSPC biology: the secreted RNase Angiogenin, the cytokine IL18 and the adhesion molecule Embigin and discovered that all of these factors are HSPC quiescence regulators. Our proximity-based differential single cell approach therefore reveals molecular heterogeneity within niche cells and can be used to identify novel extrinsic stem/progenitor cell regulators. Similar approaches could also be applied to other stem cell/niche pairs to advance understanding of microenvironmental regulation of stem cell function. PMID:27524439

Lasp-1 regulates podosome function.

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Miriam Stölting

Full Text Available Eukaryotic cells form a variety of adhesive structures to connect with their environment and to regulate cell motility. In contrast to classical focal adhesions, podosomes, highly dynamic structures of different cell types, are actively engaged in matrix remodelling and degradation. Podosomes are composed of an actin-rich core region surrounded by a ring-like structure containing signalling molecules, motor proteins as well as cytoskeleton-associated proteins. Lasp-1 is a ubiquitously expressed, actin-binding protein that is known to regulate cytoskeleton architecture and cell migration. This multidomain protein is predominantely present at focal adhesions, however, a second pool of Lasp-1 molecules is also found at lamellipodia and vesicle-like microdomains in the cytosol.In this report, we show that Lasp-1 is a novel component and regulator of podosomes. Immunofluorescence studies reveal a localization of Lasp-1 in the podosome ring structure, where it colocalizes with zyxin and vinculin. Life cell imaging experiments demonstrate that Lasp-1 is recruited in early steps of podosome assembly. A siRNA-mediated Lasp-1 knockdown in human macrophages affects podosome dynamics as well as their matrix degradation capacity. In summary, our data indicate that Lasp-1 is a novel component of podosomes and is involved in the regulation of podosomal function.

Lysophosphatidic acid signaling via LPA_1 and LPA_3 regulates cellular functions during tumor progression in pancreatic cancer cells

International Nuclear Information System (INIS)

Fukushima, Kaori; Takahashi, Kaede; Yamasaki, Eri; Onishi, Yuka; Fukushima, Nobuyuki; Honoki, Kanya; Tsujiuchi, Toshifumi

2017-01-01

Lysophosphatidic acid (LPA) signaling via G protein-coupled LPA receptors exhibits a variety of biological effects, such as cell proliferation, motility and differentiation. The aim of this study was to evaluate the roles of LPA_1 and LPA_3 in cellular functions during tumor progression in pancreatic cancer cells. LPA_1 and LPA_3 knockdown cells were generated from PANC-1 cells. The cell motile and invasive activities of PANC-1 cells were inhibited by LPA_1 and LPA_3 knockdown. In gelatin zymography, LPA_1 and LPA_3 knockdown cells indicated the low activation of matrix metalloproteinase-2 (MMP-2) in the presence of LPA. Next, to assess whether LPA_1 and LPA_3 regulate cellular functions induced by anticancer drug, PANC-1 cells were treated with cisplatin (CDDP) for approximately 6 months. The cell motile and invasive activities of long-term CDDP treated cells were markedly higher than those of PANC-1 cells, correlating with the expression levels of LPAR1 and LPAR3 genes. In soft agar assay, the long-term CDDP treated cells formed markedly large sized colonies. In addition, the cell motile and invasive activities enhanced by CDDP were significantly suppressed by LPA_1 and LPA_3 knockdown as well as colony formation. These results suggest that LPA signaling via LPA_1 and LPA_3 play an important role in the regulation of cellular functions during tumor progression in PANC-1 cells. - Highlights: • The cell motile and invasive activities of PANC-1 cells were stimulated by LPA_1 and LPA_3. • LPA_1 and LPA_3 enhanced MMP-2 activation in PANC-1 cells. • The expressions of LPAR1 and LPAR3 genes were elevated in PANC-1 cells treated with cisplatin. • The cell motile and invasive activities of PANC-1 cells treated with cisplatin were suppressed by LPA_1 and LPA_3 knockdown. • LPA_1 and LPA_3 are involved in the regulation of cellular functions during tumor progression in PANC-1 cells.

Transcription factors involved in the regulation of natural killer cell development and function: an update

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Martha Elia Luevano

2012-10-01

Full Text Available Natural Killer (NK cells belong to the innate immune system and are key effectors in the immune response against cancer and infection. Recent studies have contributed to the knowledge of events controlling NK cell fate. The use of knockout mice has enabled the discovery of key transcription factors (TFs essential for NK cell development and function. Yet, unwrapping the downstream targets of these TFs and their influence on NK cells remains a challenge. In this review we discuss the latest TFs described to be involved in the regulation of NK cell development and maturation.

Proximity-Based Differential Single-Cell Analysis of the Niche to Identify Stem/Progenitor Cell Regulators.

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Silberstein, Lev; Goncalves, Kevin A; Kharchenko, Peter V; Turcotte, Raphael; Kfoury, Youmna; Mercier, Francois; Baryawno, Ninib; Severe, Nicolas; Bachand, Jacqueline; Spencer, Joel A; Papazian, Ani; Lee, Dongjun; Chitteti, Brahmananda Reddy; Srour, Edward F; Hoggatt, Jonathan; Tate, Tiffany; Lo Celso, Cristina; Ono, Noriaki; Nutt, Stephen; Heino, Jyrki; Sipilä, Kalle; Shioda, Toshihiro; Osawa, Masatake; Lin, Charles P; Hu, Guo-Fu; Scadden, David T

2016-10-06

Physiological stem cell function is regulated by secreted factors produced by niche cells. In this study, we describe an unbiased approach based on the differential single-cell gene expression analysis of mesenchymal osteolineage cells close to, and further removed from, hematopoietic stem/progenitor cells (HSPCs) to identify candidate niche factors. Mesenchymal cells displayed distinct molecular profiles based on their relative location. We functionally examined, among the genes that were preferentially expressed in proximal cells, three secreted or cell-surface molecules not previously connected to HSPC biology-the secreted RNase angiogenin, the cytokine IL18, and the adhesion molecule Embigin-and discovered that all of these factors are HSPC quiescence regulators. Therefore, our proximity-based differential single-cell approach reveals molecular heterogeneity within niche cells and can be used to identify novel extrinsic stem/progenitor cell regulators. Similar approaches could also be applied to other stem cell/niche pairs to advance the understanding of microenvironmental regulation of stem cell function. Copyright © 2016 Elsevier Inc. All rights reserved.

A Novel Function for the Streptococcus pneumoniae Aminopeptidase N: Inhibition of T Cell Effector Function through Regulation of TCR Signaling

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Lance K. Blevins

2017-11-01

Full Text Available Streptococcus pneumoniae (Spn causes a variety of disease states including fatal bacterial pneumonia. Our previous finding that introduction of Spn into an animal with ongoing influenza virus infection resulted in a CD8+ T cell population with reduced effector function gave rise to the possibility of direct regulation by pneumococcal components. Here, we show that treatment of effector T cells with lysate derived from Spn resulted in inhibition of IFNγ and tumor necrosis factor α production as well as of cytolytic granule release. Spn aminopeptidase N (PepN was identified as the inhibitory bacterial component and surprisingly, this property was independent of the peptidase activity found in this family of proteins. Inhibitory activity was associated with reduced activation of ZAP-70, ERK1/2, c-Jun N-terminal kinase, and p38, demonstrating the ability of PepN to negatively regulate TCR signaling at multiple points in the cascade. These results reveal a novel immune regulatory function for a bacterial aminopeptidase.

Phosphodiesterases regulate airway smooth muscle function in health and disease.

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Krymskaya, Vera P; Panettieri, Reynold A

2007-01-01

On the basis of structure, regulation, and kinetic properties, phosphodiesterases (PDEs) represent a superfamily of enzymes divided into 11 subfamilies that catalyze cytosolic levels of 3',5'-cyclic adenosine monophosphate (cAMP) or 3',5'-cyclic guanosine monophosphate (cGMP) to 5'-AMP or 5'-GMP, respectively. PDE4 represents the major PDE expressed in inflammatory cells as well as airway smooth muscle (ASM), and selective PDE4 inhibitors provide a broad spectrum of anti-inflammatory effects such as abrogating cytokine and chemokine release from inflammatory cells and inhibiting inflammatory cell trafficking. Due to cell- and tissue-specific gene expression and regulation, PDEs modulate unique organ-based functions. New tools or compounds that selectively inhibit PDE subfamilies and genetically engineered mice deficient in selective isoforms have greatly enhanced our understanding of PDE function in airway inflammation and resident cell function. This chapter will focus on recent advances in our understanding of the role of PDE in regulating ASM function.

Physiology of cell volume regulation in vertebrates

DEFF Research Database (Denmark)

Hoffmann, Else K; Lambert, Ian H; Pedersen, Stine F

2009-01-01

and their regulation by, e.g., membrane deformation, ionic strength, Ca(2+), protein kinases and phosphatases, cytoskeletal elements, GTP binding proteins, lipid mediators, and reactive oxygen species, upon changes in cell volume. We also discuss the nature of the upstream elements in volume sensing in vertebrate...... organisms. Importantly, cell volume impacts on a wide array of physiological processes, including transepithelial transport; cell migration, proliferation, and death; and changes in cell volume function as specific signals regulating these processes. A discussion of this issue concludes the review.......The ability to control cell volume is pivotal for cell function. Cell volume perturbation elicits a wide array of signaling events, leading to protective (e.g., cytoskeletal rearrangement) and adaptive (e.g., altered expression of osmolyte transporters and heat shock proteins) measures and, in most...

Nfatc2 and Tob1 have non-overlapping function in T cell negative regulation and tumorigenesis.

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Sarah L May

Full Text Available Nfatc2 and Tob1 are intrinsic negative regulators of T cell activation. Nfatc2-deficient and Tob1-deficient T cells show reduced thresholds of activation; however, whether these factors have independent or overlapping roles in negative regulation of T cell responses has not been previously examined. Here, we show that Nfatc2 knockout (KO but not Tob1 KO mice have age-associated accumulation of persistently activated T cells in vivo and expansion of the CD44+ memory cell compartment and age-associated lymphocytic infiltrates in visceral organs, without significant changes in numbers of CD4+CD25+Foxp3+ regulatory T cells (Treg. In vitro, CD4+CD25- "conventional" T cells (Tconvs from both KO strains showed greater proliferation than wild type (WT Tconvs. However, while Tregs from Nfatc2 KO mice retained normal suppressive function, Tregs from Tob1 KOs had enhanced suppressive activity. Nfatc2 KO Tconvs expanded somewhat more rapidly than WT Tconvs under conditions of homeostatic proliferation, but their accelerated growth capacity was negated, at least acutely, in a lymphoreplete environment. Finally, Nfatc2 KO mice developed a previously uncharacterized increase in B-cell malignancies, which was not accelerated by the absence of Tob1. The data thus support the prevailing hypothesis that Nfatc2 and Tob1 are non-redundant regulators of lymphocyte homeostasis.

Reactive Oxygen Species Regulate the Inflammatory Function of NKT Cells through Promyelocytic Leukemia Zinc Finger.

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Kim, Yeung-Hyen; Kumar, Ajay; Chang, Cheong-Hee; Pyaram, Kalyani

2017-11-15

Reactive oxygen species (ROS) are byproducts of aerobic metabolism and contribute to both physiological and pathological conditions as second messengers. ROS are essential for activation of T cells, but how ROS influence NKT cells is unknown. In the present study, we investigated the role of ROS in NKT cell function. We found that NKT cells, but not CD4 or CD8 T cells, have dramatically high ROS in the spleen and liver of mice but not in the thymus or adipose tissues. Accordingly, ROS-high NKT cells exhibited increased susceptibility and apoptotic cell death with oxidative stress. High ROS in the peripheral NKT cells were primarily produced by NADPH oxidases and not mitochondria. We observed that sorted ROS-high NKT cells were enriched in NKT1 and NKT17 cells, whereas NKT2 cells were dominant in ROS-low cells. Furthermore, treatment of NKT cells with antioxidants led to reduced frequencies of IFN-γ- and IL-17-expressing cells, indicating that ROS play a role in regulating the inflammatory function of NKT cells. The transcription factor promyelocytic leukemia zinc finger (PLZF) seemed to control the ROS levels. NKT cells from adipose tissues that do not express PLZF and those from PLZF haplodeficient mice have low ROS. Conversely, ROS were highly elevated in CD4 T cells from mice ectopically expressing PLZF. Thus, our findings demonstrate that PLZF controls ROS levels, which in turn governs the inflammatory function of NKT cells. Copyright © 2017 by The American Association of Immunologists, Inc.

Codon usage regulates protein structure and function by affecting translation elongation speed in Drosophila cells.

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Zhao, Fangzhou; Yu, Chien-Hung; Liu, Yi

2017-08-21

Codon usage biases are found in all eukaryotic and prokaryotic genomes and have been proposed to regulate different aspects of translation process. Codon optimality has been shown to regulate translation elongation speed in fungal systems, but its effect on translation elongation speed in animal systems is not clear. In this study, we used a Drosophila cell-free translation system to directly compare the velocity of mRNA translation elongation. Our results demonstrate that optimal synonymous codons speed up translation elongation while non-optimal codons slow down translation. In addition, codon usage regulates ribosome movement and stalling on mRNA during translation. Finally, we show that codon usage affects protein structure and function in vitro and in Drosophila cells. Together, these results suggest that the effect of codon usage on translation elongation speed is a conserved mechanism from fungi to animals that can affect protein folding in eukaryotic organisms. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Microglia and Beyond: Innate Immune Cells As Regulators of Brain Development and Behavioral Function

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Kathryn M. Lenz

2018-04-01

Full Text Available Innate immune cells play a well-documented role in the etiology and disease course of many brain-based conditions, including multiple sclerosis, Alzheimer’s disease, traumatic brain and spinal cord injury, and brain cancers. In contrast, it is only recently becoming clear that innate immune cells, primarily brain resident macrophages called microglia, are also key regulators of brain development. This review summarizes the current state of knowledge regarding microglia in brain development, with particular emphasis on how microglia during development are distinct from microglia later in life. We also summarize the effects of early life perturbations on microglia function in the developing brain, the role that biological sex plays in microglia function, and the potential role that microglia may play in developmental brain disorders. Finally, given how new the field of developmental neuroimmunology is, we highlight what has yet to be learned about how innate immune cells shape the development of brain and behavior.

Microglia and Beyond: Innate Immune Cells As Regulators of Brain Development and Behavioral Function.

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Lenz, Kathryn M; Nelson, Lars H

2018-01-01

Innate immune cells play a well-documented role in the etiology and disease course of many brain-based conditions, including multiple sclerosis, Alzheimer's disease, traumatic brain and spinal cord injury, and brain cancers. In contrast, it is only recently becoming clear that innate immune cells, primarily brain resident macrophages called microglia, are also key regulators of brain development. This review summarizes the current state of knowledge regarding microglia in brain development, with particular emphasis on how microglia during development are distinct from microglia later in life. We also summarize the effects of early life perturbations on microglia function in the developing brain, the role that biological sex plays in microglia function, and the potential role that microglia may play in developmental brain disorders. Finally, given how new the field of developmental neuroimmunology is, we highlight what has yet to be learned about how innate immune cells shape the development of brain and behavior.

The role of extracellular matrix metalloproteinase inducer (EMMPRIN) in the regulation of bovine endometrial cell functions.

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Mishra, Birendra; Kizaki, Keiichiro; Sato, Takashi; Ito, Akira; Hashizume, Kazuyoshi

2012-06-01

Extracellular matrix metalloproteinase inducer (EMMPRIN) is a cell surface glycoprotein that stimulates the production of several matrix metalloproteinases (MMPs) for tissue remodeling. Previously, we detected EMMPRIN in the bovine endometrium, and it is mainly expressed in the luminal and glandular epithelium whereas MMPs are expressed in the underlying stroma. From this expression pattern, we hypothesized that EMMPRIN may regulate stromal MMPs in endometrial cell functions. To test this hypothesis, a coculture of epithelial and stromal cells was performed using a transwell system. In the coculture, epithelial cells were cultured on the insert membrane and stromal cell on the surface of well plates. Expression of stromal MMP-2 and MMP-14 was significantly higher in coculture with epithelial cell. Further, with the addition of anti-EMMPRIN antibody into the epithelial cell compartment, the expression of stromal EMMPRIN and MMP-2 and MMP-14 was decreased. To identify the active site of EMMPRIN for the augmentation of MMPs, EMMPRIN synthetic peptides that correspond to the extracellular loop domain-I (EM1, EM2, EM3, and EM4) were added into the epithelial cell compartment, and only EM2 at a higher dose interfered with EMMPRIN-mediated expression of MMP-14. Next, we examined the effects of progesterone and/or estrogen on the expression of EMMPRIN, MMP-2, and MMP-14. Progesterone (300 nM) significantly stimulated the expression of EMMPRIN but had no effects on any of the MMPs. These results suggest that EMMPRIN derived from epithelial cells regulates MMPs in the endometrium under progesterone-rich conditions and may thereby modulate bovine endometrial cell functions during gestation.

Different regulation of P-glycoprotein function between Caco-2 and Caki-1 cells by ezrin, radixin and moesin proteins.

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Yano, Kentaro; Otsuka, Kyoma; Kato, Yuko; Kawabata, Hideaki; Ohmori, Shinya; Arakawa, Hiroshi; Ogihara, Takuo

2016-03-01

P-glycoprotein (P-gp) mediates efflux of many xenobiotics, including therapeutic drugs, from normal and tumour tissues, and its functional localization on the plasma membrane of cells is regulated by scaffold proteins, such as ezrin, radixin and moesin (ERM proteins). We previously reported that radixin is involved in post-translational regulation of P-gp in hepatocellular carcinoma HepG2 cells and mouse small intestine, but not in mouse kidney. Here, we investigated whether the role of ERM proteins in regulation of P-gp transport activity in cancers is the same as that in the corresponding normal tissues, using human colon adenocarcinoma (Caco-2) cells and renal carcinoma (Caki-1) cells. In Caco-2 cells, radixin silencing alone reduced the P-gp-mediated intracellular accumulation of rhodamine123 (Rho123), while the mRNA level of P-gp was unchanged. Thus, it appears that only radixin among the ERMs regulates P-gp activity in Caco-2 cells. On the other hand, none of the ERM proteins influenced P-gp activity in Caki-1 cells. The regulation of P-gp by ERM proteins is different between Caco-2 and Caki-1 cells. Moreover, these regulatory properties are the same as those of the corresponding normal tissues, and suggest that tissue-specific differences in the regulation of P-gp by ERM proteins are retained in cancerous tissues. © 2016 Royal Pharmaceutical Society, Journal of Pharmacy and Pharmacology.

Microenvironmental regulation of hematopoietic stem cells and its implications in leukemogenesis.

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Seshadri, Madhav; Qu, Cheng-Kui

2016-07-01

Hematopoietic stem cells (HSCs) are a population of cells in the bone marrow which can self-renew, differentiate into late lineage progenitors, or remain quiescent. HSCs exist alongside several cell types in the bone marrow microenvironment that comprise the stem cell niche. These cells regulate HSC function and can contribute to leukemogenesis. In this review we will discuss recent advances in this field. In the vascular niche, arteriolar and sinusoidal zones appear to play distinct roles in HSC function. Endothelial cells modulate HSC function via Notch and other signaling pathways. In the endosteal niche multiple cell types regulate HSCs. Osteoblasts promote HSC quiescence via secreted factors and possibly physical interactions, whereas adipocytes may oppose HSC quiescence. The balance of these opposing factors depends on metabolic cues. Feedback from HSC-derived cells, including macrophages and megakaryocytes also appears to regulate HSC quiescence. Dysfunction of the bone marrow microenvironment, including mesenchymal stem cell-derived stromal cells and the sympathetic nervous system can induce or alter the progression of hematologic malignancies. Many cell types in the bone marrow microenvironment affect HSC function and contribute to malignancy. Further understanding how HSCs are regulated by the microenvironment has clinical implications for stem cell transplantation and other therapies for hematologic malignancies.

Hormonal regulation of Na+/K+-dependent ATPase activity and pump function in corneal endothelial cells.

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Hatou, Shin

2011-10-01

Na- and K-dependent ATPase (Na,K-ATPase) in the basolateral membrane of corneal endothelial cells plays an important role in the pump function of the corneal endothelium. We investigated the role of dexamethasone in the regulation of Na,K-ATPase activity and pump function in these cells. Mouse corneal endothelial cells were exposed to dexamethasone or insulin. ATPase activity was evaluated by spectrophotometric measurement, and pump function was measured using an Ussing chamber. Western blotting and immunocytochemistry were performed to measure the expression of the Na,K-ATPase α1-subunit. Dexamethasone increased Na,K-ATPase activity and the pump function of endothelial cells. Western blot analysis indicated that dexamethasone increased the expression of the Na,K-ATPase α1-subunit but decreased the ratio of active to inactive Na,K-ATPase α1-subunit. Insulin increased Na,K-ATPase activity and pump function of cultured corneal endothelial cells. These effects were transient and blocked by protein kinase C inhibitors and inhibitors of protein phosphatases 1 (PP1) and 2A (PP2A). Western blot analysis indicated that insulin decreased the amount of inactive Na,K-ATPase α1-subunit, but the expression of total Na,K-ATPase α1-subunit was unchanged. Immunocytochemistry showed that insulin increased cell surface expression of the Na,K-ATPase α1-subunit. Our results suggest that dexamethasone and insulin stimulate Na,K-ATPase activity in mouse corneal endothelial cells. The effect of dexamethasone activation in these cells was mediated by Na,K-ATPase synthesis and an increased enzymatic activity because of dephosphorylation of Na,K-ATPase α1-subunits. The effect of insulin is mediated by the protein kinase C, PP1, and/or PP2A pathways.

Interleukin 21 and its receptor are involved in NK cell expansion and regulation of lymphocyte function.

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Parrish-Novak, J; Dillon, S R; Nelson, A; Hammond, A; Sprecher, C; Gross, J A; Johnston, J; Madden, K; Xu, W; West, J; Schrader, S; Burkhead, S; Heipel, M; Brandt, C; Kuijper, J L; Kramer, J; Conklin, D; Presnell, S R; Berry, J; Shiota, F; Bort, S; Hambly, K; Mudri, S; Clegg, C; Moore, M; Grant, F J; Lofton-Day, C; Gilbert, T; Rayond, F; Ching, A; Yao, L; Smith, D; Webster, P; Whitmore, T; Maurer, M; Kaushansky, K; Holly, R D; Foster, D

2000-11-02

Cytokines are important in the regulation of haematopoiesis and immune responses, and can influence lymphocyte development. Here we have identified a class I cytokine receptor that is selectively expressed in lymphoid tissues and is capable of signal transduction. The full-length receptor was expressed in BaF3 cells, which created a functional assay for ligand detection and cloning. Conditioned media from activated human CD3+ T cells supported proliferation of the assay cell line. We constructed a complementary DNA expression library from activated human CD3+ T cells, and identified a cytokine with a four-helix-bundle structure using functional cloning. This cytokine is most closely related to IL2 and IL15, and has been designated IL21 with the receptor designated IL21 R. In vitro assays suggest that IL21 has a role in the proliferation and maturation of natural killer (NK) cell populations from bone marrow, in the proliferation of mature B-cell populations co-stimulated with anti-CD40, and in the proliferation of T cells co-stimulated with anti-CD3.

Involvement of FFA1 and FFA4 in the regulation of cellular functions during tumor progression in colon cancer cells.

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Takahashi, Kaede; Fukushima, Kaori; Onishi, Yuka; Minami, Kanako; Otagaki, Shiho; Ishimoto, Kaichi; Fukushima, Nobuyuki; Honoki, Kanya; Tsujiuchi, Toshifumi

2018-08-01

Free fatty acid receptor 1 (FFA1) and FFA4 mediate a variety of biological responses through binding of medium- and long-chain free fatty acids. The aim of this study was to investigate an involvement of FFA1 and FFA4 in the regulation of cellular functions during tumor progression in colon cancer cells. The long-term fluorouracil (5-FU) and cisplatin (CDDP) treated cells were generated from DLD1 cells (DLD-5FU and DLD-CDDP cells, respectively). FFAR1 expressions were lower in DLD-5FU and DLD-CDDP cells than in DLD1 cells. In contrast, DLD-5FU and DLD-CDDP cells showed the high FFAR4 expressions, compared with DLD1 cells. The cell motile activities of DLD-5FU and DLD-CDDP cells were reduced by GW9508 which is an agonist of FFA1 and FFA4. Moreover, GW1100, an antagonist of FFA1, inhibited the cell motile activities of DLD-5FU and DLD-CDDP cells. To evaluate whether FFA1 and FFA4 regulate the enhancement of cell motility, invasion and colony formation, highly migratory (hmDLD1) cells were established from DLD1 cells. FFAR1 expression was significantly higher in hmDLD1 cells than in DLD1 cells, but no change of FFAR4 expression was observed. The elevated cell motile and invasive activities and colony formation of hmDLD1 cells were suppressed by FFA1 inhibition. These results suggest that FFA1 and FFA4 are involved in the regulation of cellular functions during tumor progression in colon cancer DLD1 cells. Copyright © 2018 Elsevier Inc. All rights reserved.

Regulation of dendritic cell function by insulin/IGF-1/PI3K/Akt signaling through klotho expression.

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Xuan, Nguyen Thi; Hoang, Nguyen Huy; Nhung, Vu Phuong; Duong, Nguyen Thuy; Ha, Nguyen Hai; Hai, Nong Van

2017-06-01

Insulin or insulin-like growth factor 1 (IGF-1) promotes the activation of phosphoinositide 3 kinase (PI3K)/Akt signaling in immune cells including dendritic cells (DCs), the most potent professional antigen-presenting cells for naive T cells. Klotho, an anti-aging protein, participates in the regulation of the PI3K/Akt signaling, thus the Ca 2+ -dependent migration is reduced in klotho-deficient DCs. The present study explored the effects of insulin/IGF-1 on DC function through klotho expression. To this end, the mouse bone marrow cells were isolated and cultured with GM-CSF to attain bone marrow-derived DCs (BMDCs). Cells were treated with insulin or IGF-1 and followed by stimulating with lipopolysaccharides (LPS). Tumor necrosis factor (TNF)-α formation was examined by enzyme-linked immunosorbent assay (ELISA). Phagocytosis was analyzed by FITC-dextran uptake assay. The expression of klotho was determined by quantitative PCR, immunoprecipitation and western blotting. As a result, treatment of the cells with insulin/IGF-1 resulted in reducing the klotho expression as well as LPS-stimulated TNF-α release and increasing the FITC-dextran uptake but unaltering reactive oxygen species (ROS) production in BMDCs. The effects were abolished by using pharmacological inhibition of PI3K/Akt with LY294002 and paralleled by transfecting DCs with klotho siRNA. In conclusion, the regulation of klotho sensitive DC function by IGF-1 or insulin is mediated through PI3K/Akt signaling pathway in BMDCs.

Distinct Molecular Signature of Murine Fetal Liver and Adult Hematopoietic Stem Cells Identify Novel Regulators of Hematopoietic Stem Cell Function.

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Manesia, Javed K; Franch, Monica; Tabas-Madrid, Daniel; Nogales-Cadenas, Ruben; Vanwelden, Thomas; Van Den Bosch, Elisa; Xu, Zhuofei; Pascual-Montano, Alberto; Khurana, Satish; Verfaillie, Catherine M

2017-04-15

During ontogeny, fetal liver (FL) acts as a major site for hematopoietic stem cell (HSC) maturation and expansion, whereas HSCs in the adult bone marrow (ABM) are largely quiescent. HSCs in the FL possess faster repopulation capacity as compared with ABM HSCs. However, the molecular mechanism regulating the greater self-renewal potential of FL HSCs has not yet extensively been assessed. Recently, we published RNA sequencing-based gene expression analysis on FL HSCs from 14.5-day mouse embryo (E14.5) in comparison to the ABM HSCs. We reanalyzed these data to identify key transcriptional regulators that play important roles in the expansion of HSCs during development. The comparison of FL E14.5 with ABM HSCs identified more than 1,400 differentially expressed genes. More than 200 genes were shortlisted based on the gene ontology (GO) annotation term "transcription." By morpholino-based knockdown studies in zebrafish, we assessed the function of 18 of these regulators, previously not associated with HSC proliferation. Our studies identified a previously unknown role for tdg, uhrf1, uchl5, and ncoa1 in the emergence of definitive hematopoiesis in zebrafish. In conclusion, we demonstrate that identification of genes involved in transcriptional regulation differentially expressed between expanding FL HSCs and quiescent ABM HSCs, uncovers novel regulators of HSC function.

Fumarate hydratase is a critical metabolic regulator of hematopoietic stem cell functions.

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Guitart, Amelie V; Panagopoulou, Theano I; Villacreces, Arnaud; Vukovic, Milica; Sepulveda, Catarina; Allen, Lewis; Carter, Roderick N; van de Lagemaat, Louie N; Morgan, Marcos; Giles, Peter; Sas, Zuzanna; Gonzalez, Marta Vila; Lawson, Hannah; Paris, Jasmin; Edwards-Hicks, Joy; Schaak, Katrin; Subramani, Chithra; Gezer, Deniz; Armesilla-Diaz, Alejandro; Wills, Jimi; Easterbrook, Aaron; Coman, David; So, Chi Wai Eric; O'Carroll, Donal; Vernimmen, Douglas; Rodrigues, Neil P; Pollard, Patrick J; Morton, Nicholas M; Finch, Andrew; Kranc, Kamil R

2017-03-06

Strict regulation of stem cell metabolism is essential for tissue functions and tumor suppression. In this study, we investigated the role of fumarate hydratase (Fh1), a key component of the mitochondrial tricarboxylic acid (TCA) cycle and cytosolic fumarate metabolism, in normal and leukemic hematopoiesis. Hematopoiesis-specific Fh1 deletion (resulting in endogenous fumarate accumulation and a genetic TCA cycle block reflected by decreased maximal mitochondrial respiration) caused lethal fetal liver hematopoietic defects and hematopoietic stem cell (HSC) failure. Reexpression of extramitochondrial Fh1 (which normalized fumarate levels but not maximal mitochondrial respiration) rescued these phenotypes, indicating the causal role of cellular fumarate accumulation. However, HSCs lacking mitochondrial Fh1 (which had normal fumarate levels but defective maximal mitochondrial respiration) failed to self-renew and displayed lymphoid differentiation defects. In contrast, leukemia-initiating cells lacking mitochondrial Fh1 efficiently propagated Meis1 / Hoxa9 -driven leukemia. Thus, we identify novel roles for fumarate metabolism in HSC maintenance and hematopoietic differentiation and reveal a differential requirement for mitochondrial Fh1 in normal hematopoiesis and leukemia propagation. © 2017 Guitart et al.

Lysophosphatidic acid signaling via LPA{sub 1} and LPA{sub 3} regulates cellular functions during tumor progression in pancreatic cancer cells

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Fukushima, Kaori; Takahashi, Kaede; Yamasaki, Eri; Onishi, Yuka [Division of Molecular Oncology, Department of Life Science, Faculty of Science and Engineering, Kindai University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502 (Japan); Fukushima, Nobuyuki [Division of Molecular Neurobiology, Department of Life Science, Faculty of Science and Engineering, Kindai University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502 (Japan); Honoki, Kanya [Department of Orthopedic Surgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Tsujiuchi, Toshifumi, E-mail: ttujiuch@life.kindai.ac.jp [Division of Molecular Oncology, Department of Life Science, Faculty of Science and Engineering, Kindai University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502 (Japan)

2017-03-01

Lysophosphatidic acid (LPA) signaling via G protein-coupled LPA receptors exhibits a variety of biological effects, such as cell proliferation, motility and differentiation. The aim of this study was to evaluate the roles of LPA{sub 1} and LPA{sub 3} in cellular functions during tumor progression in pancreatic cancer cells. LPA{sub 1} and LPA{sub 3} knockdown cells were generated from PANC-1 cells. The cell motile and invasive activities of PANC-1 cells were inhibited by LPA{sub 1} and LPA{sub 3} knockdown. In gelatin zymography, LPA{sub 1} and LPA{sub 3} knockdown cells indicated the low activation of matrix metalloproteinase-2 (MMP-2) in the presence of LPA. Next, to assess whether LPA{sub 1} and LPA{sub 3} regulate cellular functions induced by anticancer drug, PANC-1 cells were treated with cisplatin (CDDP) for approximately 6 months. The cell motile and invasive activities of long-term CDDP treated cells were markedly higher than those of PANC-1 cells, correlating with the expression levels of LPAR1 and LPAR3 genes. In soft agar assay, the long-term CDDP treated cells formed markedly large sized colonies. In addition, the cell motile and invasive activities enhanced by CDDP were significantly suppressed by LPA{sub 1} and LPA{sub 3} knockdown as well as colony formation. These results suggest that LPA signaling via LPA{sub 1} and LPA{sub 3} play an important role in the regulation of cellular functions during tumor progression in PANC-1 cells. - Highlights: • The cell motile and invasive activities of PANC-1 cells were stimulated by LPA{sub 1} and LPA{sub 3}. • LPA{sub 1} and LPA{sub 3} enhanced MMP-2 activation in PANC-1 cells. • The expressions of LPAR1 and LPAR3 genes were elevated in PANC-1 cells treated with cisplatin. • The cell motile and invasive activities of PANC-1 cells treated with cisplatin were suppressed by LPA{sub 1} and LPA{sub 3} knockdown. • LPA{sub 1} and LPA{sub 3} are involved in the regulation of cellular functions during tumor

Functional Impairment of Myeloid Dendritic Cells during Advanced Stage of HIV-1 Infection: Role of Factors Regulating Cytokine Signaling.

Directory of Open Access Journals (Sweden)

Meenakshi Sachdeva

Full Text Available Severely immunocompromised state during advanced stage of HIV-1 infection has been linked to functionally defective antigen presentation by dendritic cells (DCs. The molecular mechanisms behind DC impairment are still obscure. We investigated changes in DC function and association of key regulators of cytokine signaling during different stages of HIV-1 infection and following antiretroviral therapy (ART.Phenotypic and functional characteristics of circulating myeloid DCs (mDCs in 56 ART-naive patients (23 in early and 33 in advanced stage of disease, 36 on ART and 24 healthy controls were evaluated. Sixteen patients were studied longitudinally prior-to and 6 months after the start of ART. For functional studies, monocyte-derived DCs (Mo-DCs were evaluated for endocytosis, allo-stimulation and cytokine secretion. The expression of suppressor of cytokine signaling (SOCS-1 and other regulators of cytokine signaling was evaluated by real-time RT-PCR.The ability to respond to an antigenic stimulation was severely impaired in patients in advanced HIV-1 disease which showed partial recovery in the treated group. Mo-DCs from patients with advanced HIV-disease remained immature with low allo-stimulation and reduced cytokine secretion even after TLR-4 mediated stimulation ex-vivo. The cells had an increased expression of negative regulatory factors like SOCS-1, SOCS-3, SH2-containing phosphatase (SHP-1 and a reduced expression of positive regulators like Janus kinase (JAK2 and Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB1. A functional recovery after siRNA mediated silencing of SOCS-1 in these mo-DCs confirms the role of negative regulatory factors in functional impairment of these cells.Functionally defective DCs in advanced stage of HIV-1 infection seems to be due to imbalanced state of negative and positive regulatory gene expression. Whether this is a cause or effect of increased viral replication at this stage of disease

Role of protein kinase C in regulation of Na+- and K +-dependent ATPase activity and pump function in corneal endothelial cells.

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Hatou, Shin; Yamada, Masakazu; Mochizuki, Hiroshi; Nishida, Teruo

2009-05-01

Na+- and K+-dependent ATPase (Na,K-ATPase) plays an important role in the pump function of the corneal endothelium. We investigated the possible role of protein kinase C (PKC) in regulation of Na,K-ATPase activity and pump function in corneal endothelial cells. Confluent monolayers of mouse corneal endothelial cells were exposed to phorbol 12,13-dibutyrate (PDBu) to induce activation of PKC. ATPase activity of the cells was evaluated by using ammonium molybdate in spectrophotometric measurement of phosphate released from ATP, with Na,K-ATPase activity being defined as the portion of total ATPase activity sensitive to ouabain. Pump function of the cells was measured with a Ussing chamber, with the pump function attributable to Na,K-ATPase activity being defined as the portion of the total short-circuit current sensitive to ouabain. PDBu (10(-7) M) increased the Na,K-ATPase activity and pump function of the cultured cells. These effects of PDBu were potentiated by the cyclooxygenase inhibitor indomethacin and the cytochrome P(450) inhibitor resorufin and were blocked by okadaic acid, an inhibitor of protein phosphatases 1 and 2A. Our results suggest that PKC bidirectionally regulates Na,K-ATPase activity in mouse corneal endothelial cells: it inhibits Na,K-ATPase activity in a cyclooxygenase- and cytochrome P(450)-dependent manner, whereas it stimulates such activity by activating protein phosphatases 1 or 2A.

Integrating physiological regulation with stem cell and tissue homeostasis

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Nakada, Daisuke; Levi, Boaz P.; Morrison, Sean J.

2015-01-01

Summary Stem cells are uniquely able to self-renew, to undergo multilineage differentiation, and to persist throughout life in a number of tissues. Stem cells are regulated by a combination of shared and tissue-specific mechanisms and are distinguished from restricted progenitors by differences in transcriptional and epigenetic regulation. Emerging evidence suggests that other aspects of cellular physiology, including mitosis, signal transduction, and metabolic regulation also differ between stem cells and their progeny. These differences may allow stem cells to be regulated independently of differentiated cells in response to circadian rhythms, changes in metabolism, diet, exercise, mating, aging, infection, and disease. This allows stem cells to sustain homeostasis or to remodel relevant tissues in response to physiological change. Stem cells are therefore not only regulated by short-range signals that maintain homeostasis within their tissue of origin, but also by long-range signals that integrate stem cell function with systemic physiology. PMID:21609826

EZH2: a pivotal regulator in controlling cell differentiation.

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Chen, Ya-Huey; Hung, Mien-Chie; Li, Long-Yuan

2012-01-01

Epigenetic regulation plays an important role in stem cell self-renewal, maintenance and lineage differentiation. The epigenetic profiles of stem cells are related to their transcriptional signature. Enhancer of Zeste homlog 2 (EZH2), a catalytic subunit of epigenetic regulator Polycomb repressive complex 2 (PRC2), has been shown to be a key regulator in controlling cellular differentiation. EZH2 is a histone methyltransferase that not only methylates histone H3 on Lys 27 (H3K27me3) but also interacts with and recruits DNA methyltransferases to methylate CpG at certain EZH2 target genes to establish firm repressive chromatin structures, contributing to tumor progression and the regulation of development and lineage commitment both in embryonic stem cells (ESCs) and adult stem cells. In addition to its well-recognized epigenetic gene silencing function, EZH2 also directly methylates nonhistone targets such as the cardiac transcription factor, GATA4, resulting in attenuated GATA4 transcriptional activity and gene repression. This review addresses recent progress toward the understanding of the biological functions and regulatory mechanisms of EZH2 and its targets as well as their roles in stem cell maintenance and cell differentiation.

The Drosophila T-box transcription factor Midline functions within the Notch–Delta signaling pathway to specify sensory organ precursor cell fates and regulates cell survival within the eye imaginal disc

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Das, Sudeshna; Chen, Q. Brent; Saucier, Joseph D.; Drescher, Brandon; Zong, Yan; Morgan, Sarah; Forstall, John; Meriwether, Andrew; Toranzo, Randy; Leal, Sandra M.

2014-01-01

We report that the T-box transcription factor Midline (Mid), an evolutionary conserved homolog of the vertebrate Tbx20 protein, functions within the Notch–Delta signaling pathway essential for specifying the fates of sensory organ precursor cells. This complements an established history of research showing that Mid regulates the cell-fate specification of diverse cell types within the developing heart, epidermis and central nervous system. Tbx20 has been detected in diverse neuronal and epithelial cells of embryonic eye tissues in both mice and humans. However, the mechanisms by which either Mid or Tbx20 function to regulate cell-fate specification or other critical aspects of eye development including cell survival have not yet been elucidated. We have also gathered preliminary evidence suggesting that Mid may play an indirect, but vital role in selecting SOP cells within the third-instar larval eye disc by regulating the expression of the proneural gene atonal. During subsequent pupal stages, Mid specifies SOP cell fates as a member of the Notch–Delta signaling hierarchy and is essential for maintaining cell viability within by inhibiting apoptotic pathways. We present several new hypotheses that seek to understand the role of Mid in regulating developmental processes downstream of the Notch receptor that are critical for specifying unique cell fates, patterning the adult eye and maintaining cellular homeostasis during eye disc morphogenesis. PMID:23962751

Regulation of proliferation and functioning of transplanted cells by using herpes simplex virus thymidine kinase gene in mice.

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Tsujimura, Mari; Kusamori, Kosuke; Oda, Chihiro; Miyazaki, Airi; Katsumi, Hidemasa; Sakane, Toshiyasu; Nishikawa, Makiya; Yamamoto, Akira

2018-04-10

Though cell transplantation is becoming an attractive therapeutic method, uncontrolled cell proliferation or overexpression of cellular functions could cause adverse effects. These unfavorable outcomes could be avoided by regulating the proliferation or functioning of transplanted cells. In this study, we used a combination of the herpes simplex virus thymidine kinase (HSVtk) gene, a suicide gene, and ganciclovir (GCV) to control the proliferation and functioning of insulin-secreting cells after transplantation in diabetic mice. Mouse pancreatic β cell line MIN6 cells were selected as insulin-secreting cells for transfection with the HSVtk gene to obtain MIN6/HSVtk cells. Proliferation of MIN6/HSVtk cells was suppressed by GCV in a concentration-dependent manner; 0.25 μg/mL GCV maintained a constant number of MIN6/HSVtk cells for at least 16 days. MIN6 or MIN6/HSVtk cells were then transplanted to streptozotocin-induced diabetic mice. Mice transplanted with MIN6 cells exhibited hypoglycemia irrespective of GCV administration. In contrast, normal (around 150 mg/dL) blood glucose levels were maintained in mice transplanted with MIN6/HSVtk cells by a daily administration of 50 mg/kg of GCV. These results indicate that controlling the proliferation and functioning of HSVtk gene-expressing cells by GCV could greatly improve the usefulness and safety of cell-based therapy. Copyright © 2018 Elsevier B.V. All rights reserved.

Regulation of adult neural progenitor cell functions by purinergic signaling.

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Tang, Yong; Illes, Peter

2017-02-01

Extracellular purines are signaling molecules in the neurogenic niches of the brain and spinal cord, where they activate cell surface purinoceptors at embryonic neural stem cells (NSCs) and adult neural progenitor cells (NPCs). Although mRNA and protein are expressed at NSCs/NPCs for almost all subtypes of the nucleotide-sensitive P2X/P2Y, and the nucleoside-sensitive adenosine receptors, only a few of those have acquired functional significance. ATP is sequentially degraded by ecto-nucleotidases to ADP, AMP, and adenosine with agonistic properties for distinct receptor-classes. Nucleotides/nucleosides facilitate or inhibit NSC/NPC proliferation, migration and differentiation. The most ubiquitous effect of all agonists (especially of ATP and ADP) appears to be the facilitation of cell proliferation, usually through P2Y1Rs and sometimes through P2X7Rs. However, usually P2X7R activation causes necrosis/apoptosis of NPCs. Differentiation can be initiated by P2Y2R-activation or P2X7R-blockade. A key element in the transduction mechanism of either receptor is the increase of the intracellular free Ca 2+ concentration, which may arise due to its release from intracellular storage sites (G protein-coupling; P2Y) or due to its passage through the receptor-channel itself from the extracellular space (ATP-gated ion channel; P2X). Further research is needed to clarify how purinergic signaling controls NSC/NPC fate and how the balance between the quiescent and activated states is established with fine and dynamic regulation. GLIA 2017;65:213-230. © 2016 Wiley Periodicals, Inc.

The adventitia: essential regulator of vascular wall structure and function.

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Stenmark, Kurt R; Yeager, Michael E; El Kasmi, Karim C; Nozik-Grayck, Eva; Gerasimovskaya, Evgenia V; Li, Min; Riddle, Suzette R; Frid, Maria G

2013-01-01

The vascular adventitia acts as a biological processing center for the retrieval, integration, storage, and release of key regulators of vessel wall function. It is the most complex compartment of the vessel wall and is composed of a variety of cells, including fibroblasts, immunomodulatory cells (dendritic cells and macrophages), progenitor cells, vasa vasorum endothelial cells and pericytes, and adrenergic nerves. In response to vascular stress or injury, resident adventitial cells are often the first to be activated and reprogrammed to influence the tone and structure of the vessel wall; to initiate and perpetuate chronic vascular inflammation; and to stimulate expansion of the vasa vasorum, which can act as a conduit for continued inflammatory and progenitor cell delivery to the vessel wall. This review presents the current evidence demonstrating that the adventitia acts as a key regulator of vascular wall function and structure from the outside in.

Peptide regulators of peripheral taste function.

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Dotson, Cedrick D; Geraedts, Maartje C P; Munger, Steven D

2013-03-01

The peripheral sensory organ of the gustatory system, the taste bud, contains a heterogeneous collection of sensory cells. These taste cells can differ in the stimuli to which they respond and the receptors and other signaling molecules they employ to transduce and encode those stimuli. This molecular diversity extends to the expression of a varied repertoire of bioactive peptides that appear to play important functional roles in signaling taste information between the taste cells and afferent sensory nerves and/or in processing sensory signals within the taste bud itself. Here, we review studies that examine the expression of bioactive peptides in the taste bud and the impact of those peptides on taste functions. Many of these peptides produced in taste buds are known to affect appetite, satiety or metabolism through their actions in the brain, pancreas and other organs, suggesting a functional link between the gustatory system and the neural and endocrine systems that regulate feeding and nutrient utilization. Copyright © 2013 Elsevier Ltd. All rights reserved.

Nrf2 regulates cellular behaviors and Notch signaling in oral squamous cell carcinoma cells.

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Fan, Hong; Paiboonrungruan, Chorlada; Zhang, Xinyan; Prigge, Justin R; Schmidt, Edward E; Sun, Zheng; Chen, Xiaoxin

2017-11-04

Oxidative stress is known to play a pivotal role in the development of oral squamous cell carcinoma (OSCC). We have demonstrated that activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway has chemopreventive effects against oxidative stress-associated OSCC. However, Nrf2 have dual roles in cancer development; while it prevents carcinogenesis of normal cells, hyperactive Nrf2 also promotes the survival of cancer cells. This study is aimed to understand the function of Nrf2 in regulating cellular behaviors of OSCC cells, and the potential mechanisms through which Nrf2 facilitates OSCC. We established the Nrf2-overexpressing and Nrf2-knockdown OSCC cell lines, and examined the function of Nrf2 in regulating cell proliferation, migration, invasion, cell cycle and colony formation. Our data showed that Nrf2 overexpression promoted cancer phenotypes in OSCC cells, whereas Nrf2 silencing inhibited these phenotypes. In addition, Nrf2 positively regulated Notch signaling pathway in OSCC cells in vitro. Consistent with this observation, Nrf2 activation in Keap1 -/- mice resulted in not only hyperproliferation of squamous epithelial cells in mouse tongue as evidenced by increased expression of PCNA, but also activation of Notch signaling in these cells as evidenced by increased expression of NICD1 and Hes1. In conclusion, Nrf2 regulates cancer behaviors and Notch signaling in OSCC cells. Copyright © 2017 Elsevier Inc. All rights reserved.

Differentiation, distribution and gammadelta T cell-driven regulation of IL-22-producing T cells in tuberculosis.

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Shuyu Yao

2010-02-01

Full Text Available Differentiation, distribution and immune regulation of human IL-22-producing T cells in infections remain unknown. Here, we demonstrated in a nonhuman primate model that M. tuberculosis infection resulted in apparent increases in numbers of T cells capable of producing IL-22 de novo without in vitro Ag stimulation, and drove distribution of these cells more dramatically in lungs than in blood and lymphoid tissues. Consistently, IL-22-producing T cells were visualized in situ in lung tuberculosis (TB granulomas by confocal microscopy and immunohistochemistry, indicating that mature IL-22-producing T cells were present in TB granuloma. Surprisingly, phosphoantigen HMBPP activation of Vgamma2Vdelta2 T cells down-regulated the capability of T cells to produce IL-22 de novo in lymphocytes from blood, lung/BAL fluid, spleen and lymph node. Up-regulation of IFNgamma-producing Vgamma2Vdelta2 T effector cells after HMBPP stimulation coincided with the down-regulated capacity of these T cells to produce IL-22 de novo. Importantly, anti-IFNgamma neutralizing Ab treatment reversed the HMBPP-mediated down-regulation effect on IL-22-producing T cells, suggesting that Vgamma2Vdelta2 T-cell-driven IFNgamma-networking function was the mechanism underlying the HMBPP-mediated down-regulation of the capability of T cells to produce IL-22. These novel findings raise the possibility to ultimately investigate the function of IL-22 producing T cells and to target Vgamma2Vdelta2 T cells for balancing potentially hyper-activating IL-22-producing T cells in severe TB.

The Drosophila T-box transcription factor Midline functions within the Notch-Delta signaling pathway to specify sensory organ precursor cell fates and regulates cell survival within the eye imaginal disc.

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Das, Sudeshna; Chen, Q Brent; Saucier, Joseph D; Drescher, Brandon; Zong, Yan; Morgan, Sarah; Forstall, John; Meriwether, Andrew; Toranzo, Randy; Leal, Sandra M

2013-01-01

We report that the T-box transcription factor Midline (Mid), an evolutionary conserved homolog of the vertebrate Tbx20 protein, functions within the Notch-Delta signaling pathway essential for specifying the fates of sensory organ precursor (SOP) cells. These findings complement an established history of research showing that Mid regulates the cell-fate specification of diverse cell types within the developing heart, epidermis and central nervous system. Tbx20 has been detected in unique neuronal and epithelial cells of embryonic eye tissues in both mice and humans. However, the mechanisms by which either Mid or Tbx20 function to regulate cell-fate specification or other critical aspects of eye development including cell survival have not yet been elucidated. We have also gathered preliminary evidence suggesting that Mid may play an indirect, but vital role in selecting SOP cells within the third-instar larval eye disc by regulating the expression of the proneural gene atonal. During subsequent pupal stages, Mid specifies SOP cell fates as a member of the Notch-Delta signaling hierarchy and is essential for maintaining cell viability by inhibiting apoptotic pathways. We present several new hypotheses that seek to understand the role of Mid in regulating developmental processes downstream of the Notch receptor that are critical for specifying unique cell fates, patterning the adult eye and maintaining cellular homeostasis during eye disc morphogenesis. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Ion channels involved in cell volume regulation: effects on migration, proliferation, and programmed cell death in non adherent EAT cells and adherent ELA cells.

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Hoffmann, Else Kay

2011-01-01

This mini review outlines studies of cell volume regulation in two closely related mammalian cell lines: nonadherent Ehrlich ascites tumour cells (EATC) and adherent Ehrlich Lettre ascites (ELA) cells. Focus is on the regulatory volume decrease (RVD) that occurs after cell swelling, the volume regulatory ion channels involved, and the mechanisms (cellular signalling pathways) that regulate these channels. Finally, I shall also briefly review current investigations in these two cell lines that focuses on how changes in cell volume can regulate cell functions such as cell migration, proliferation, and programmed cell death. Copyright © 2011 S. Karger AG, Basel.

Innate lymphoid cells as regulators of immunity, inflammation and tissue homeostasis.

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Klose, Christoph S N; Artis, David

2016-06-21

Research over the last 7 years has led to the formal identification of innate lymphoid cells (ILCs), increased the understanding of their tissue distribution and has established essential functions of ILCs in diverse physiological processes. These include resistance to pathogens, the regulation of autoimmune inflammation, tissue remodeling, cancer and metabolic homeostasis. Notably, many ILC functions appear to be regulated by mechanisms distinct from those of other innate and adaptive immune cells. In this Review, we focus on how group 2 ILC (ILC2) and group 3 ILC (ILC3) responses are regulated and how these cells interact with other immune and non-immune cells to mediate their functions. We highlight experimental evidence from mouse models and patient-based studies that have elucidated the effects of ILCs on the maintenance of tissue homeostasis and the consequences for health and disease.

Mitochondrial fission proteins regulate programmed cell death in yeast.

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Fannjiang, Yihru; Cheng, Wen-Chih; Lee, Sarah J; Qi, Bing; Pevsner, Jonathan; McCaffery, J Michael; Hill, R Blake; Basañez, Gorka; Hardwick, J Marie

2004-11-15

The possibility that single-cell organisms undergo programmed cell death has been questioned in part because they lack several key components of the mammalian cell death machinery. However, yeast encode a homolog of human Drp1, a mitochondrial fission protein that was shown previously to promote mammalian cell death and the excessive mitochondrial fragmentation characteristic of apoptotic mammalian cells. In support of a primordial origin of programmed cell death involving mitochondria, we found that the Saccharomyces cerevisiae homolog of human Drp1, Dnm1, promotes mitochondrial fragmentation/degradation and cell death following treatment with several death stimuli. Two Dnm1-interacting factors also regulate yeast cell death. The WD40 repeat protein Mdv1/Net2 promotes cell death, consistent with its role in mitochondrial fission. In contrast to its fission function in healthy cells, Fis1 unexpectedly inhibits Dnm1-mediated mitochondrial fission and cysteine protease-dependent cell death in yeast. Furthermore, the ability of yeast Fis1 to inhibit mitochondrial fission and cell death can be functionally replaced by human Bcl-2 and Bcl-xL. Together, these findings indicate that yeast and mammalian cells have a conserved programmed death pathway regulated by a common molecular component, Drp1/Dnm1, that is inhibited by a Bcl-2-like function.

MicroRNAs regulate T-cell production of interleukin-9 and identify hypoxia-inducible factor-2α as an important regulator of T helper 9 and regulatory T-cell differentiation.

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Singh, Yogesh; Garden, Oliver A; Lang, Florian; Cobb, Bradley S

2016-09-01

MicroRNAs (miRNAs) regulate many aspects of helper T cell (Th) development and function. Here we found that they are required for the suppression of interleukin-9 (IL-9) expression in Th9 cells and other Th subsets. Two highly related miRNAs (miR-15b and miR-16) that we previously found to play an important role in regulatory T (Treg) cell differentiation were capable of suppressing IL-9 expression when they were over-expressed in Th9 cells. We used these miRNAs as tools to identify novel regulators of IL-9 expression and found that they could regulate the expression of Epas1, which encodes hypoxia-inducible factor (HIF)-2α. HIF proteins regulate metabolic pathway usage that is important in determining appropriate Th differentiation. The related protein, HIF-1α enhances Th17 differentiation and inhibits Treg cell differentiation. Here we found that HIF-2α was required for IL-9 expression in Th9 cells, but its expression was not sufficient in other Th subsets. Furthermore, HIF-2α suppressed Treg cell differentiation like HIF-1α, demonstrating both similar and distinct roles of the HIF proteins in Th differentiation and adding a further dimension to their function. Ironically, even though miR-15b and miR-16 suppressed HIF-2α expression in Treg cells, inhibiting their function in Treg cells did not lead to an increase in IL-9 expression. Therefore, the physiologically relevant miRNAs that regulate IL-9 expression in Treg cells and other subsets remain unknown. Nevertheless, the analysis of miR-15b and miR-16 function led to the discovery of the importance of HIF-2α so this work demonstrated the utility of studying miRNA function to identify novel regulatory pathways in helper T-cell development. © 2016 John Wiley & Sons Ltd.

Regulation of K-Cl cotransport: from function to genes.

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Adragna, N C; Di Fulvio, M; Lauf, P K

2004-10-01

This review intends to summarize the vast literature on K-Cl cotransport (COT) regulation from a functional and genetic viewpoint. Special attention has been given to the signaling pathways involved in the transporter's regulation found in several tissues and cell types, and more specifically, in vascular smooth muscle cells (VSMCs). The number of publications on K-Cl COT has been steadily increasing since its discovery at the beginning of the 1980s, with red blood cells (RBCs) from different species (human, sheep, dog, rabbit, guinea pig, turkey, duck, frog, rat, mouse, fish, and lamprey) being the most studied model. Other tissues/cell types under study are brain, kidney, epithelia, muscle/smooth muscle, tumor cells, heart, liver, insect cells, endothelial cells, bone, platelets, thymocytes and Leishmania donovani. One of the salient properties of K-Cl-COT is its activation by cell swelling and its participation in the recovery of cell volume, a process known as regulatory volume decrease (RVD). Activation by thiol modification with N-ethylmaleimide (NEM) has spawned investigations on the redox dependence of K-Cl COT, and is used as a positive control for the operation of the system in many tissues and cells. The most accepted model of K-Cl COT regulation proposes protein kinases and phosphatases linked in a chain of phosphorylation/dephosphorylation events. More recent studies include regulatory pathways involving the phosphatidyl inositol/protein kinase C (PKC)-mediated pathway for regulation by lithium (Li) in low-K sheep red blood cells (LK SRBCs), and the nitric oxide (NO)/cGMP/protein kinase G (PKG) pathway as well as the platelet-derived growth factor (PDGF)-mediated mechanism in VSMCs. Studies on VSM transfected cells containing the PKG catalytic domain demonstrated the participation of this enzyme in K-Cl COT regulation. Commonly used vasodilators activate K-Cl COT in a dose-dependent manner through the NO/cGMP/PKG pathway. Interaction between the

Cell-cycle regulation of non-enzymatic functions of the Drosophila methyltransferase PR-Set7.

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Zouaz, Amel; Fernando, Céline; Perez, Yannick; Sardet, Claude; Julien, Eric; Grimaud, Charlotte

2018-04-06

Tight cell-cycle regulation of the histone H4-K20 methyltransferase PR-Set7 is essential for the maintenance of genome integrity. In mammals, this mainly involves the interaction of PR-Set7 with the replication factor PCNA, which triggers the degradation of the enzyme by the CRL4CDT2 E3 ubiquitin ligase. PR-Set7 is also targeted by the SCFβ-TRCP ligase, but the role of this additional regulatory pathway remains unclear. Here, we show that Drosophila PR-Set7 undergoes a cell-cycle proteolytic regulation, independently of its interaction with PCNA. Instead, Slimb, the ortholog of β-TRCP, is specifically required for the degradation of the nuclear pool of PR-Set7 prior to S phase. Consequently, inactivation of Slimb leads to nuclear accumulation of PR-Set7, which triggers aberrant chromatin compaction and G1/S arrest. Strikingly, these phenotypes result from non-enzymatic PR-Set7 functions that prevent proper histone H4 acetylation independently of H4K20 methylation. Altogether, these results identify the Slimb-mediated PR-Set7 proteolysis as a new critical regulatory mechanism required for proper interphase chromatin organization at G1/S transition.

Functional study and regional mapping of 44 hormono-regulated genes isolated from a porcine granulosa cell library

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Hatey François

2001-01-01

Full Text Available Abstract cDNA clones from a pig granulosa cell cDNA library were isolated by differential hybridisation for follicle stimulating hormone (FSH regulation in granulosa cells in a previous study. The clones that did not match any known sequence were studied for their expression in granulosa cells (treated or not by FSH and in fresh isolated ovarian follicles mainly by comparative RT-PCR analysis. These results give functional data on genes that may be implicated in follicular growing. These ESTs have been localised on the porcine genome, using a somatic cell hybrid panel, providing new type I markers on the porcine map and information on the comparative map between humans and pigs.

Proteinase-Activated Receptor 1 (PAR1 regulates leukemic stem cell functions.

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Nicole Bäumer

Full Text Available External signals that are mediated by specific receptors determine stem cell fate. The thrombin receptor PAR1 plays an important role in haemostasis, thrombosis and vascular biology, but also in tumor biology and angiogenesis. Its expression and function in hematopoietic stem cells is largely unknown. Here, we analyzed expression and function of PAR1 in primary hematopoietic cells and their leukemic counterparts. AML patients' blast cells expressed much lower levels of PAR1 mRNA and protein than CD34+ progenitor cells. Constitutive Par1-deficiency in adult mice did not affect engraftment or stem cell potential of hematopoietic cells. To model an AML with Par1-deficiency, we retrovirally introduced the oncogene MLL-AF9 in wild type and Par1-/- hematopoietic progenitor cells. Par1-deficiency did not alter initial leukemia development. However, the loss of Par1 enhanced leukemic stem cell function in vitro and in vivo. Re-expression of PAR1 in Par1-/- leukemic stem cells delayed leukemogenesis in vivo. These data indicate that Par1 contributes to leukemic stem cell maintenance.

Proteinase-Activated Receptor 1 (PAR1) regulates leukemic stem cell functions.

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Bäumer, Nicole; Krause, Annika; Köhler, Gabriele; Lettermann, Stephanie; Evers, Georg; Hascher, Antje; Bäumer, Sebastian; Berdel, Wolfgang E; Müller-Tidow, Carsten; Tickenbrock, Lara

2014-01-01

External signals that are mediated by specific receptors determine stem cell fate. The thrombin receptor PAR1 plays an important role in haemostasis, thrombosis and vascular biology, but also in tumor biology and angiogenesis. Its expression and function in hematopoietic stem cells is largely unknown. Here, we analyzed expression and function of PAR1 in primary hematopoietic cells and their leukemic counterparts. AML patients' blast cells expressed much lower levels of PAR1 mRNA and protein than CD34+ progenitor cells. Constitutive Par1-deficiency in adult mice did not affect engraftment or stem cell potential of hematopoietic cells. To model an AML with Par1-deficiency, we retrovirally introduced the oncogene MLL-AF9 in wild type and Par1-/- hematopoietic progenitor cells. Par1-deficiency did not alter initial leukemia development. However, the loss of Par1 enhanced leukemic stem cell function in vitro and in vivo. Re-expression of PAR1 in Par1-/- leukemic stem cells delayed leukemogenesis in vivo. These data indicate that Par1 contributes to leukemic stem cell maintenance.

LRRK2 regulates voltage-gated calcium channel function.

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Cade eBedford

2016-05-01

Full Text Available Voltage-gated Ca2+ (CaV channels enable Ca2+ influx in response to membrane depolarization. CaV2.1 channels are localized to the presynaptic membrane of many types of neurons where they are involved in triggering neurotransmitter release. Several signaling proteins have been identified as important CaV2.1 regulators including protein kinases, G-proteins and Ca2+ binding proteins. Recently, we discovered that leucine rich repeat kinase 2 (LRRK2, a protein associated with inherited Parkinson’s disease, interacts with specific synaptic proteins and influences synaptic transmission. Since synaptic proteins functionally interact with CaV2.1 channels and synaptic transmission is triggered by Ca2+ entry via CaV2.1, we investigated whether LRRK2 could impact CaV2.1 channel function. CaV2.1 channel properties were measured using whole cell patch clamp electrophysiology in HEK293 cells transfected with CaV2.1 subunits and various LRRK2 constructs. Our results demonstrate that both wild type LRRK2 and the G2019S LRRK2 mutant caused a significant increase in whole cell Ca2+ current density compared to cells expressing only the CaV2.1 channel complex. In addition, LRRK2 expression caused a significant hyperpolarizing shift in voltage-dependent activation while having no significant effect on inactivation properties. These functional changes in CaV2.1 activity are likely due to a direct action of LRRK2 as we detected a physical interaction between LRRK2 and the β3 CaV channel subunit via coimmunoprecipitation. Furthermore, effects on CaV2.1 channel function are dependent on LRRK2 kinase activity as these could be reversed via treatment with a LRRK2 inhibitor. Interestingly, LRRK2 also augmented endogenous voltage-gated Ca2+ channel function in PC12 cells suggesting other CaV channels could also be regulated by LRRK2. Overall, our findings support a novel physiological role for LRRK2 in regulating CaV2.1 function that could have implications for how

Red Blood Cell Function and Dysfunction: Redox Regulation, Nitric Oxide Metabolism, Anemia

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Kuhn, Viktoria; Diederich, Lukas; Keller, T.C. Stevenson; Kramer, Christian M.; Lückstädt, Wiebke; Panknin, Christina; Suvorava, Tatsiana; Isakson, Brant E.; Kelm, Malte

2017-01-01

Abstract Significance: Recent clinical evidence identified anemia to be correlated with severe complications of cardiovascular disease (CVD) such as bleeding, thromboembolic events, stroke, hypertension, arrhythmias, and inflammation, particularly in elderly patients. The underlying mechanisms of these complications are largely unidentified. Recent Advances: Previously, red blood cells (RBCs) were considered exclusively as transporters of oxygen and nutrients to the tissues. More recent experimental evidence indicates that RBCs are important interorgan communication systems with additional functions, including participation in control of systemic nitric oxide metabolism, redox regulation, blood rheology, and viscosity. In this article, we aim to revise and discuss the potential impact of these noncanonical functions of RBCs and their dysfunction in the cardiovascular system and in anemia. Critical Issues: The mechanistic links between changes of RBC functional properties and cardiovascular complications related to anemia have not been untangled so far. Future Directions: To allow a better understanding of the complications associated with anemia in CVD, basic and translational science studies should be focused on identifying the role of noncanonical functions of RBCs in the cardiovascular system and on defining intrinsic and/or systemic dysfunction of RBCs in anemia and its relationship to CVD both in animal models and clinical settings. Antioxid. Redox Signal. 26, 718–742. PMID:27889956

Invariant NKT cells: regulation and function during viral infection.

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Jennifer A Juno

Full Text Available Natural killer T cells (NKT cells represent a subset of T lymphocytes that express natural killer (NK cell surface markers. A subset of NKT cells, termed invariant NKT cells (iNKT, express a highly restricted T cell receptor (TCR and respond to CD1d-restricted lipid ligands. iNKT cells are now appreciated to play an important role in linking innate and adaptive immune responses and have been implicated in infectious disease, allergy, asthma, autoimmunity, and tumor surveillance. Advances in iNKT identification and purification have allowed for the detailed study of iNKT activity in both humans and mice during a variety of chronic and acute infections. Comparison of iNKT function between non-pathogenic simian immunodeficiency virus (SIV infection models and chronic HIV-infected patients implies a role for iNKT activity in controlling immune activation. In vitro studies of influenza infection have revealed novel effector functions of iNKT cells including IL-22 production and modulation of myeloid-derived suppressor cells, but ex vivo characterization of human iNKT cells during influenza infection are lacking. Similarly, as recent evidence suggests iNKT involvement in dengue virus pathogenesis, iNKT cells may modulate responses to a number of emerging pathogens. This Review will summarize current knowledge of iNKT involvement in responses to viral infections in both human and mouse models and will identify critical gaps in knowledge and opportunities for future study. We will also highlight recent efforts to harness iNKT ligands as vaccine adjuvants capable of improving vaccination-induced cellular immune responses.

Functional and molecular characterization of transmembrane intracellular pH regulators in human dental pulp stem cells.

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Chen, Gunng-Shinng; Lee, Shiao-Pieng; Huang, Shu-Fu; Chao, Shih-Chi; Chang, Chung-Yi; Wu, Gwo-Jang; Li, Chung-Hsing; Loh, Shih-Hurng

2018-06-01

Homeostasis of intracellular pH (pH i ) plays vital roles in many cell functions, such as proliferation, apoptosis, differentiation and metastasis. Thus far, Na + -H + exchanger (NHE), Na + -HCO 3 - co-transporter (NBC), Cl - /HCO 3 - exchanger (AE) and Cl - /OH - exchanger (CHE) have been identified to co-regulate pH i homeostasis. However, functional and biological pH i -regulators in human dental pulp stem cells (hDPSCs) have yet to be identified. Microspectrofluorimetry technique with pH-sensitive fluorescent dye, BCECF, was used to detect pH i changes. NH 4 Cl and Na + -acetate pre-pulse were used to induce intracellular acidosis and alkalosis, respectively. Isoforms of pH i -regulators were detected by Western blot technique. The resting pH i was no significant difference between that in HEPES-buffered (nominal HCO 3 - -free) solution or CO 2 /HCO 3 -buffered system (7.42 and 7.46, respectively). The pH i recovery following the induced-intracellular acidosis was blocked completely by removing [Na + ] o , while only slowed (-63%) by adding HOE694 (a NHE1 specific inhibitor) in HEPES-buffered solution. The pH i recovery was inhibited entirely by removing [Na + ] o , while adding HOE 694 pulse DIDS (an anion-transporter inhibitor) only slowed (-55%) the acid extrusion. Both in HEPES-buffered and CO 2 /HCO 3 -buffered system solution, the pH i recovery after induced-intracellular alkalosis was entirely blocked by removing [Cl - ] o . Western blot analysis showed the isoforms of pH i regulators, including NHE1/2, NBCe1/n1, AE1/2/3/4 and CHE in the hDPSCs. We demonstrate for the first time that resting pH i is significantly higher than 7.2 and meditates functionally by two Na + -dependent acid extruders (NHE and NBC), two Cl - -dependent acid loaders (CHE and AE) and one Na + -independent acid extruder(s) in hDPSCs. These findings provide novel insight for basic and clinical treatment of dentistry. Copyright © 2018 Elsevier Ltd. All rights reserved.

Cloning of B cell-specific membrane tetraspanning molecule BTS possessing B cell proliferation-inhibitory function.

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Suenaga, Tadahiro; Arase, Hisashi; Yamasaki, Sho; Kohno, Masayuki; Yokosuka, Tadashi; Takeuchi, Arata; Hattori, Takamichi; Saito, Takashi

2007-11-01

Lymphocyte proliferation is regulated by signals through antigen receptors, co-stimulatory receptors, and other positive and negative modulators. Several membrane tetraspanning molecules are also involved in the regulation of lymphocyte growth and death. We cloned a new B cell-specific tetraspanning (BTS) membrane molecule, which is similar to CD20 in terms of expression, structure and function. BTS is specifically expressed in the B cell line and its expression is increased after the pre-B cell stage. BTS is expressed in intracellular granules and on the cell surface. Overexpression of BTS in immature B cell lines induces growth retardation through inhibition of cell cycle progression and cell size increase without inducing apoptosis. This inhibitory function is mediated predominantly by the N terminus of BTS. The development of mature B cells is inhibited in transgenic mice expressing BTS, suggesting that BTS is involved in the in vivo regulation of B cells. These results indicate that BTS plays a role in the regulation of cell division and B cell growth.

Gap junctions in cells of the immune system: structure, regulation and possible functional roles

Directory of Open Access Journals (Sweden)

J.C. Sáez

2000-04-01

Full Text Available Gap junction channels are sites of cytoplasmic communication between contacting cells. In vertebrates, they consist of protein subunits denoted connexins (Cxs which are encoded by a gene family. According to their Cx composition, gap junction channels show different gating and permeability properties that define which ions and small molecules permeate them. Differences in Cx primary sequences suggest that channels composed of different Cxs are regulated differentially by intracellular pathways under specific physiological conditions. Functional roles of gap junction channels could be defined by the relative importance of permeant substances, resulting in coordination of electrical and/or metabolic cellular responses. Cells of the native and specific immune systems establish transient homo- and heterocellular contacts at various steps of the immune response. Morphological and functional studies reported during the last three decades have revealed that many intercellular contacts between cells in the immune response present gap junctions or "gap junction-like" structures. Partial characterization of the molecular composition of some of these plasma membrane structures and regulatory mechanisms that control them have been published recently. Studies designed to elucidate their physiological roles suggest that they might permit coordination of cellular events which favor the effective and timely response of the immune system.

Mast Cell Function

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da Silva, Elaine Zayas Marcelino; Jamur, Maria Célia

2014-01-01

Since first described by Paul Ehrlich in 1878, mast cells have been mostly viewed as effectors of allergy. It has been only in the past two decades that mast cells have gained recognition for their involvement in other physiological and pathological processes. Mast cells have a widespread distribution and are found predominantly at the interface between the host and the external environment. Mast cell maturation, phenotype and function are a direct consequence of the local microenvironment and have a marked influence on their ability to specifically recognize and respond to various stimuli through the release of an array of biologically active mediators. These features enable mast cells to act as both first responders in harmful situations as well as to respond to changes in their environment by communicating with a variety of other cells implicated in physiological and immunological responses. Therefore, the critical role of mast cells in both innate and adaptive immunity, including immune tolerance, has gained increased prominence. Conversely, mast cell dysfunction has pointed to these cells as the main offenders in several chronic allergic/inflammatory disorders, cancer and autoimmune diseases. This review summarizes the current knowledge of mast cell function in both normal and pathological conditions with regards to their regulation, phenotype and role. PMID:25062998

Transcriptional regulation of pancreas development and β-cell function [Review].

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Fujitani, Yoshio

2017-05-30

A small number of cells in the adult pancreas are endocrine cells. They are arranged in clusters called islets of Langerhans. The islets make insulin, glucagon, and other endocrine hormones, and release them into the blood circulation. These hormones help control the level of blood glucose. Therefore, a dysfunction of endocrine cells in the pancreas results in impaired glucose homeostasis, or diabetes mellitus. The pancreas is an organ that originates from the evaginations of pancreatic progenitor cells in the epithelium of the foregut endoderm. Pancreas organogenesis and maturation of the islets of Langerhans occurs via a coordinated and complex interplay of transcriptional networks and signaling molecules, which guide a stepwise and repetitive process of the propagation of progenitor cells and their maturation, eventually resulting in a fully functional organ. Increasing our understanding of the extrinsic, as well as intrinsic mechanisms that control these processes should facilitate the efforts to generate surrogate β cells from ES or iPS cells, or to reactivate the function of important cell types within pancreatic islets that are lost in diabetes.

New insights into redox regulation of stem cell self-renewal and differentiation.

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Ren, Fenglian; Wang, Kui; Zhang, Tao; Jiang, Jingwen; Nice, Edouard Collins; Huang, Canhua

2015-08-01

Reactive oxygen species (ROS), the natural byproducts of aerobic metabolism, are precisely orchestrated to evoke diverse signaling pathways. To date, studies have focused mainly on the detrimental effects of ROS in stem cells. Recently, accumulating evidence has suggested that ROS also function as second messengers that modulate stem cell self-renewal and differentiation by regulating intricate signaling networks. Although many efforts have been made to clarify the general effects of ROS on signal transduction in stem cells, less is known about the initial and direct executors of ROS signaling, which are known as 'redox sensors'. Modifications of cysteine residues in redox sensors are of significant importance in the modulation of protein function in response to different redox conditions. Intriguingly, most key molecules in ROS signaling and cell cycle regulation (including transcriptional factors and kinases) that are crucial in the regulation of stem cell self-renewal and differentiation have the potential to be redox sensors. We highlight herein the importance of redox regulation of these key regulators in stem cell self-renewal and differentiation. Understanding the mechanisms of redox regulation in stem cell self-renewal and differentiation will open exciting new perspectives for stem cell biology. This article is part of a Special Issue entitled Redox regulation of differentiation and de-differentiation. Copyright © 2015 Elsevier B.V. All rights reserved.

Ikaros limits follicular B cell activation by regulating B cell receptor signaling pathways

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Heizmann, Beate; Sellars, MacLean; Macias-Garcia, Alejandra; Chan, Susan; Kastner, Philippe

2016-01-01

The Ikaros transcription factor is essential for early B cell development, but its effect on mature B cells is debated. We show that Ikaros is required to limit the response of naive splenic B cells to B cell receptor signals. Ikaros deficient follicular B cells grow larger and enter cell cycle faster after anti-IgM stimulation. Unstimulated mutant B cells show deregulation of positive and negative regulators of signal transduction at the mRNA level, and constitutive phosphorylation of ERK, p38, SYK, BTK, AKT and LYN. Stimulation results in enhanced and prolonged ERK and p38 phosphorylation, followed by hyper-proliferation. Pharmacological inhibition of ERK and p38 abrogates the increased proliferative response of Ikaros deficient cells. These results suggest that Ikaros functions as a negative regulator of follicular B cell activation.

Ikaros limits follicular B cell activation by regulating B cell receptor signaling pathways

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Heizmann, Beate [Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR 7104, Université de Strasbourg, 67404 Illkirch (France); Sellars, MacLean [Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR 7104, Université de Strasbourg, 67404 Illkirch (France); David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Macias-Garcia, Alejandra [Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR 7104, Université de Strasbourg, 67404 Illkirch (France); Institute for Medical Engineering and Science at MIT, Cambridge, MA 02139 (United States); Chan, Susan, E-mail: scpk@igbmc.fr [Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR 7104, Université de Strasbourg, 67404 Illkirch (France); Kastner, Philippe, E-mail: scpk@igbmc.fr [Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR 7104, Université de Strasbourg, 67404 Illkirch (France); Faculté de Médecine, Université de Strasbourg, Strasbourg (France)

2016-02-12

The Ikaros transcription factor is essential for early B cell development, but its effect on mature B cells is debated. We show that Ikaros is required to limit the response of naive splenic B cells to B cell receptor signals. Ikaros deficient follicular B cells grow larger and enter cell cycle faster after anti-IgM stimulation. Unstimulated mutant B cells show deregulation of positive and negative regulators of signal transduction at the mRNA level, and constitutive phosphorylation of ERK, p38, SYK, BTK, AKT and LYN. Stimulation results in enhanced and prolonged ERK and p38 phosphorylation, followed by hyper-proliferation. Pharmacological inhibition of ERK and p38 abrogates the increased proliferative response of Ikaros deficient cells. These results suggest that Ikaros functions as a negative regulator of follicular B cell activation.

Regulation of stem-cell mediated host immunity by the sphingolipid ...

International Development Research Centre (IDRC) Digital Library (Canada)

Regulation of stem-cell mediated host immunity by the sphingolipid pathway ... in the generation of mature immune cells and the functioning of the surrounding ... methods with human cells and genetically engineered mice to examine how the ...

Tip cells: master regulators of tubulogenesis?

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Weavers, Helen; Skaer, Helen

2014-07-01

The normal development of an organ depends on the coordinated regulation of multiple cell activities. Focusing on tubulogenesis, we review the role of specialised cells or groups of cells that are selected from within tissue primordia and differentiate at the outgrowing tips or leading edge of developing tubules. Tip or leading cells develop distinctive patterns of gene expression that enable them to act both as sensors and transmitters of intercellular signalling. This enables them to explore the environment, respond to both tissue intrinsic signals and extrinsic cues from surrounding tissues and to regulate the behaviour of their neighbours, including the setting of cell fate, patterning cell division, inducing polarity and promoting cell movement and cell rearrangements by neighbour exchange. Tip cells are also able to transmit mechanical tension to promote tissue remodelling and, by interacting with the extracellular matrix, they can dictate migratory pathways and organ shape. Where separate tubular structures fuse to form networks, as in the airways of insects or the vascular system of vertebrates, specialised fusion tip cells act to interconnect disparate elements of the developing network. Finally, we consider their importance in the maturation of mature physiological function and in the development of disease. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Golgi structure formation, function, and post-translational modifications in mammalian cells.

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Huang, Shijiao; Wang, Yanzhuang

2017-01-01

The Golgi apparatus is a central membrane organelle for trafficking and post-translational modifications of proteins and lipids in cells. In mammalian cells, it is organized in the form of stacks of tightly aligned flattened cisternae, and dozens of stacks are often linked laterally into a ribbon-like structure located in the perinuclear region of the cell. Proper Golgi functionality requires an intact architecture, yet Golgi structure is dynamically regulated during the cell cycle and under disease conditions. In this review, we summarize our current understanding of the relationship between Golgi structure formation, function, and regulation, with focus on how post-translational modifications including phosphorylation and ubiquitination regulate Golgi structure and on how Golgi unstacking affects its functions, in particular, protein trafficking, glycosylation, and sorting in mammalian cells.

Renal intercalated cells and blood pressure regulation

Directory of Open Access Journals (Sweden)

Susan M. Wall

2017-12-01

Full Text Available Type B and non-A, non-B intercalated cells are found within the connecting tubule and the cortical collecting duct. Of these cell types, type B intercalated cells are known to mediate Cl⁻ absorption and HCO₃⁻ secretion largely through pendrin-dependent Cl⁻/HCO₃⁻ exchange. This exchange is stimulated by angiotensin II administration and is also stimulated in models of metabolic alkalosis, for instance after aldosterone or NaHCO₃ administration. In some rodent models, pendrin-mediated HCO₃⁻ secretion modulates acid-base balance. However, the role of pendrin in blood pressure regulation is likely of more physiological or clinical significance. Pendrin regulates blood pressure not only by mediating aldosterone-sensitive Cl⁻ absorption, but also by modulating the aldosterone response for epithelial Na⁺ channel (ENaC-mediated Na⁺ absorption. Pendrin regulates ENaC through changes in open channel of probability, channel surface density, and channels subunit total protein abundance. Thus, aldosterone stimulates ENaC activity through both direct and indirect effects, the latter occurring through its stimulation of pendrin expression and function. Therefore, pendrin contributes to the aldosterone pressor response. Pendrin may also modulate blood pressure in part through its action in the adrenal medulla, where it modulates the release of catecholamines, or through an indirect effect on vascular contractile force. This review describes how aldosterone and angiotensin II-induced signaling regulate pendrin and the contributory role of pendrin in distal nephron function and blood pressure.

Phosphorylation regulates SIRT1 function.

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Tsutomu Sasaki

Full Text Available BACKGROUND: SIR2 is an NAD(+-dependent deacetylase [1]-[3] implicated in the regulation of lifespan in species as diverse as yeast [4], worms [5], and flies [6]. We previously reported that the level of SIRT1, the mammalian homologue of SIR2 [7], [8], is coupled to the level of mitotic activity in cells both in vitro and in vivo[9]. Cells from long-lived mice maintained SIRT1 levels of young mice in tissues that undergo continuous cell replacement by proliferating stem cells. Changes in SIRT1 protein level were not associated with changes in mRNA level, suggesting that SIRT1 could be regulated post-transcriptionally. However, other than a recent report on sumoylation [10] and identification of SIRT1 as a nuclear phospho-protein by mass spectrometry [11], post-translational modifications of this important protein have not been reported. METHODOLOGY/PRINCIPAL FINDINGS: We identified 13 residues in SIRT1 that are phosphorylated in vivo using mass spectrometry. Dephosphorylation by phosphatases in vitro resulted in decreased NAD(+-dependent deacetylase activity. We identified cyclinB/Cdk1 as a cell cycle-dependent kinase that forms a complex with and phosphorylates SIRT1. Mutation of two residues phosphorylated by Cyclin B/Cdk1 (threonine 530 and serine 540 disturbs normal cell cycle progression and fails to rescue proliferation defects in SIRT1-deficient cells [12], [13]. CONCLUSIONS/SIGNIFICANCE: Pharmacological manipulation of SIRT1 activity is currently being tested as a means of extending lifespan in mammals. Treatment of obese mice with resveratrol, a pharmacological activator of SIRT1, modestly but significantly improved longevity and, perhaps more importantly, offered some protection against the development of type 2 diabetes mellitus and metabolic syndrome [14]-[16]. Understanding the endogenous mechanisms that regulate the level and activity of SIRT1, therefore, has obvious relevance to human health and disease. Our results identify

Genetic and Epigenetic Mechanisms That Maintain Hematopoietic Stem Cell Function

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Kosan, Christian; Godmann, Maren

2016-01-01

All hematopoiesis cells develop from multipotent progenitor cells. Hematopoietic stem cells (HSC) have the ability to develop into all blood lineages but also maintain their stemness. Different molecular mechanisms have been identified that are crucial for regulating quiescence and self-renewal to maintain the stem cell pool and for inducing proliferation and lineage differentiation. The stem cell niche provides the microenvironment to keep HSC in a quiescent state. Furthermore, several transcription factors and epigenetic modifiers are involved in this process. These create modifications that regulate the cell fate in a more or less reversible and dynamic way and contribute to HSC homeostasis. In addition, HSC respond in a unique way to DNA damage. These mechanisms also contribute to the regulation of HSC function and are essential to ensure viability after DNA damage. How HSC maintain their quiescent stage during the entire life is still matter of ongoing research. Here we will focus on the molecular mechanisms that regulate HSC function. PMID:26798358

Genetic and Epigenetic Mechanisms That Maintain Hematopoietic Stem Cell Function

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Christian Kosan

2016-01-01

Full Text Available All hematopoiesis cells develop from multipotent progenitor cells. Hematopoietic stem cells (HSC have the ability to develop into all blood lineages but also maintain their stemness. Different molecular mechanisms have been identified that are crucial for regulating quiescence and self-renewal to maintain the stem cell pool and for inducing proliferation and lineage differentiation. The stem cell niche provides the microenvironment to keep HSC in a quiescent state. Furthermore, several transcription factors and epigenetic modifiers are involved in this process. These create modifications that regulate the cell fate in a more or less reversible and dynamic way and contribute to HSC homeostasis. In addition, HSC respond in a unique way to DNA damage. These mechanisms also contribute to the regulation of HSC function and are essential to ensure viability after DNA damage. How HSC maintain their quiescent stage during the entire life is still matter of ongoing research. Here we will focus on the molecular mechanisms that regulate HSC function.

Role of insulin in regulation of Na+-/K+-dependent ATPase activity and pump function in corneal endothelial cells.

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Hatou, Shin; Yamada, Masakazu; Akune, Yoko; Mochizuki, Hiroshi; Shiraishi, Atsushi; Joko, Takeshi; Nishida, Teruo; Tsubota, Kazuo

2010-08-01

The Na(+)-/K(+)-dependent ATPase (Na,K-ATPase) expressed in the basolateral membrane of corneal endothelial cells plays an important role in the pump function of the corneal endothelium. The role of insulin in the regulation of Na,K-ATPase activity and pump function in corneal endothelial cells was investigated. Confluent monolayers of mouse corneal endothelial cells were exposed to insulin. ATPase activity was evaluated by spectrophotometric measurement of phosphate released from ATP with the use of ammonium molybdate; Na,K-ATPase activity was defined as the portion of total ATPase activity sensitive to ouabain. Pump function was measured with the use of a Ussing chamber; pump function attributable to Na,K-ATPase activity was defined as the portion of the total short-circuit current sensitive to ouabain. Western blot analysis and immunocytochemistry were performed to measure the expression of the Na,K-ATPase alpha(1)-subunit. Insulin increased the Na,K-ATPase activity and pump function of cultured corneal endothelial cells. These effects were blocked by protein kinase C (PKC) inhibitors and protein phosphatases 1 and 2A inhibitor. Western blot analysis indicated that insulin decreased the ratio of the inactive Na,K-ATPase alpha(1)-subunit. Immunocytochemistry indicated that insulin increased the cell surface expression of the Na,K-ATPase alpha(1)-subunit. These results suggest that insulin increases the Na,K-ATPase activity and pump function of cultured corneal endothelial cells. The effect of insulin is mediated by PKC and presumably results in the activation of PP1, 2A, or both, which are essential for activating Na,K-ATPase by alpha(1)-subunit dephosphorylation.

Cell fate regulation in the shoot meristem.

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Laux, T; Mayer, K F

1998-04-01

The shoot meristem is a proliferative centre containing pluripotent stem cells that are the ultimate source of all cells and organs continuously added to the growing shoot. The progeny of the stem cells have two developmental options, either to renew the stem cell population or to leave the meristem and to differentiate, possibly according to signals from more mature tissue. The destiny of each cell depends on its position within the dynamic shoot meristem. Genetic data suggest a simple model in which graded positional information is provided by antagonistic gene functions and is interpreted by genes which regulate cell fate.

The Haematopoietic Stem Cell Niche: New Insights into the Mechanisms Regulating Haematopoietic Stem Cell Behaviour

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Andrew J. Lilly

2011-01-01

Full Text Available The concept of the haematopoietic stem cell (HSC niche was formulated by Schofield in the 1970s, as a region within the bone marrow containing functional cell types that can maintain HSC potency throughout life. Since then, ongoing research has identified numerous cell types and a plethora of signals that not only maintain HSCs, but also dictate their behaviour with respect to homeostatic requirements and exogenous stresses. It has been proposed that there are endosteal and vascular niches within the bone marrow, which are thought to regulate different HSC populations. However, recent data depicts a more complicated picture, with functional crosstalk between cells in these two regions. In this review, recent research into the endosteal/vascular cell types and signals regulating HSC behaviour are considered, together with the possibility of a single subcompartmentalised niche.

Identification of Cell Cycle-Regulated Genes by Convolutional Neural Network.

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Liu, Chenglin; Cui, Peng; Huang, Tao

2017-01-01

The cell cycle-regulated genes express periodically with the cell cycle stages, and the identification and study of these genes can provide a deep understanding of the cell cycle process. Large false positives and low overlaps are big problems in cell cycle-regulated gene detection. Here, a computational framework called DLGene was proposed for cell cycle-regulated gene detection. It is based on the convolutional neural network, a deep learning algorithm representing raw form of data pattern without assumption of their distribution. First, the expression data was transformed to categorical state data to denote the changing state of gene expression, and four different expression patterns were revealed for the reported cell cycle-regulated genes. Then, DLGene was applied to discriminate the non-cell cycle gene and the four subtypes of cell cycle genes. Its performances were compared with six traditional machine learning methods. At last, the biological functions of representative cell cycle genes for each subtype are analyzed. Our method showed better and more balanced performance of sensitivity and specificity comparing to other machine learning algorithms. The cell cycle genes had very different expression pattern with non-cell cycle genes and among the cell-cycle genes, there were four subtypes. Our method not only detects the cell cycle genes, but also describes its expression pattern, such as when its highest expression level is reached and how it changes with time. For each type, we analyzed the biological functions of the representative genes and such results provided novel insight to the cell cycle mechanisms. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Innate lymphoid cells in autoimmunity: emerging regulators in rheumatic diseases

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Shikhagaie, Medya M.; Germar, Kristine; Bal, Suzanne M.; Ros, Xavier Romero; Spits, Hergen

2017-01-01

Innate lymphoid cells (ILCs) are important in the regulation of barrier homeostasis. These cells do not express T cell receptors but share many functional similarities with T helper cells and cytotoxic CD8(+) T lymphocytes. ILCs are divided into three groups, namely group 1 ILCs, group 2 ILCs and

Empty conformers of HLA-B preferentially bind CD8 and regulate CD8+ T cell function.

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Geng, Jie; Altman, John D; Krishnakumar, Sujatha; Raghavan, Malini

2018-05-09

When complexed with antigenic peptides, human leukocyte antigen (HLA) class I (HLA-I) molecules initiate CD8 + T cell responses via interaction with the T cell receptor (TCR) and co-receptor CD8. Peptides are generally critical for the stable cell surface expression of HLA-I molecules. However, for HLA-I alleles such as HLA-B*35:01, peptide-deficient (empty) heterodimers are thermostable and detectable on the cell surface. Additionally, peptide-deficient HLA-B*35:01 tetramers preferentially bind CD8 and to a majority of blood-derived CD8 + T cells via a CD8-dependent binding mode. Further functional studies reveal that peptide-deficient conformers of HLA-B*35:01 do not directly activate CD8 + T cells, but accumulate at the immunological synapse in antigen-induced responses, and enhance cognate peptide-induced cell adhesion and CD8 + T cell activation. Together, these findings indicate that HLA-I peptide occupancy influences CD8 binding affinity, and reveal a new set of regulators of CD8 + T cell activation, mediated by the binding of empty HLA-I to CD8. © 2018, Geng et al.

S1P receptor signalling and RGS proteins; expression and function in vascular smooth muscle cells and transfected CHO cells

NARCIS (Netherlands)

Hendriks-Balk, Mariëlle C.; van Loenen, Pieter B.; Hajji, Najat; Michel, Martin C.; Peters, Stephan L. M.; Alewijnse, Astrid E.

2009-01-01

Sphingosine-1-phosphate (S1P) signalling via G protein-coupled receptors is important for the regulation of cell function and differentiation. Specific Regulators of G protein Signalling (RGS) proteins modulate the function of these receptors in many cell types including vascular smooth muscle cells

RPS27a promotes proliferation, regulates cell cycle progression and inhibits apoptosis of leukemia cells

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Wang, Houcai; Yu, Jing; Zhang, Lixia; Xiong, Yuanyuan; Chen, Shuying; Xing, Haiyan; Tian, Zheng; Tang, Kejing; Wei, Hui; Rao, Qing; Wang, Min; Wang, Jianxiang, E-mail: wangjx@ihcams.ac.cn

2014-04-18

Highlights: • RPS27a expression was up-regulated in advanced-phase CML and AL patients. • RPS27a knockdown changed biological property of K562 and K562/G01 cells. • RPS27a knockdown affected Raf/MEK/ERK, P21 and BCL-2 signaling pathways. • RPS27a knockdown may be applicable for new combination therapy in CML patients. - Abstract: Ribosomal protein S27a (RPS27a) could perform extra-ribosomal functions besides imparting a role in ribosome biogenesis and post-translational modifications of proteins. The high expression level of RPS27a was reported in solid tumors, and we found that the expression level of RPS27a was up-regulated in advanced-phase chronic myeloid leukemia (CML) and acute leukemia (AL) patients. In this study, we explored the function of RPS27a in leukemia cells by using CML cell line K562 cells and its imatinib resistant cell line K562/G01 cells. It was observed that the expression level of RPS27a was high in K562 cells and even higher in K562/G01 cells. Further analysis revealed that RPS27a knockdown by shRNA in both K562 and K562G01 cells inhibited the cell viability, induced cell cycle arrest at S and G2/M phases and increased cell apoptosis induced by imatinib. Combination of shRNA with imatinib treatment could lead to more cleaved PARP and cleaved caspase-3 expression in RPS27a knockdown cells. Further, it was found that phospho-ERK(p-ERK) and BCL-2 were down-regulated and P21 up-regulated in RPS27a knockdown cells. In conclusion, RPS27a promotes proliferation, regulates cell cycle progression and inhibits apoptosis of leukemia cells. It appears that drugs targeting RPS27a combining with tyrosine kinase inhibitor (TKI) might represent a novel therapy strategy in TKI resistant CML patients.

Mitochondrial respiration controls lysosomal function during inflammatory T cell responses

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Baixauli, Francesc; Acín-Pérez, Rebeca; Villarroya-Beltrí, Carolina; Mazzeo, Carla; Nuñez-Andrade, Norman; Gabandé-Rodriguez, Enrique; Dolores Ledesma, Maria; Blázquez, Alberto; Martin, Miguel Angel; Falcón-Pérez, Juan Manuel; Redondo, Juan Miguel; Enríquez, Jose Antonio; Mittelbrunn, Maria

2016-01-01

Summary The endolysosomal system is critical for the maintenance of cellular homeostasis. However, how endolysosomal compartment is regulated by mitochondrial function is largely unknown. We have generated a mouse model with defective mitochondrial function in CD4+ T lymphocytes by genetic deletion of the mitochondrial transcription factor A (Tfam). Mitochondrial respiration-deficiency impairs lysosome function, promotes p62 and sphingomyelin accumulation and disrupts endolysosomal trafficking pathways and autophagy, thus linking a primary mitochondrial dysfunction to a lysosomal storage disorder. The impaired lysosome function in Tfam-deficient cells subverts T cell differentiation toward pro-inflammatory subsets and exacerbates the in vivo inflammatory response. Restoration of NAD+ levels improves lysosome function and corrects the inflammatory defects in Tfam-deficient T cells. Our results uncover a mechanism by which mitochondria regulate lysosome function to preserve T cell differentiation and effector functions, and identify novel strategies for intervention in mitochondrial-related diseases. PMID:26299452

Diacylglycerol kinases in T cell tolerance and effector function

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Shelley S Chen

2016-11-01

Full Text Available Diacylglycerol kinases (DGKs are a family of enzymes that regulate the relative levels of diacylglycerol (DAG and phosphatidic acid (PA in cells by phosphorylating DAG to produce PA. Both DAG and PA are important second messengers cascading T cell receptor (TCR signal by recruiting multiple effector molecules such as RasGRP1, PKC, and mTOR. Studies have revealed important physiological functions of DGKs in the regulation of receptor signaling and the development and activation of immune cells. In this review, we will focus on recent progresses in our understanding of two DGK isoforms,  and , in CD8 T effector and memory cell differentiation, regulatory T cell development and function, and invariant NKT cell development and effector lineage differentiation.

Crosstalk between Bcl-2 family and Ras family small GTPases: potential cell fate regulation?

International Nuclear Information System (INIS)

Kang, Jia; Pervaiz, Shazib

2013-01-01

Cell fate regulation is a function of diverse cell signaling pathways that promote cell survival and or inhibit cell death execution. In this regard, the role of the Bcl-2 family in maintaining a tight balance between cell death and cell proliferation has been extensively studied. The conventional dogma links cell fate regulation by the Bcl-2 family to its effect on mitochondrial permeabilization and apoptosis amplification. However, recent evidence provide a novel mechanism for death regulation by the Bcl-2 family via modulating cellular redox metabolism. For example overexpression of Bcl-2 has been shown to contribute to a pro-oxidant intracellular milieu and down-regulation of cellular superoxide levels enhanced death sensitivity of Bcl-2 overexpressing cells. Interestingly, gene knockdown of the small GTPase Rac1 or pharmacological inhibition of its activity also reverted death phenotype in Bcl-2 expressing cells. This appears to be a function of an interaction between Bcl-2 and Rac1. Similar functional associations have been described between the Bcl-2 family and other members of the Ras superfamily. These interactions at the mitochondria provide novel opportunities for strategic therapeutic targeting of drug-resistant cancers.

Regulation of macrophage development and function in peripheral tissues

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Lavin, Yonit; Mortha, Arthur; Rahman, Adeeb; Merad, Miriam

2015-01-01

Macrophages are immune cells of haematopoietic origin that provide crucial innate immune defence and have tissue-specific functions in the regulation and maintenance of organ homeostasis. Recent studies of macrophage ontogeny, as well as transcriptional and epigenetic identity, have started to reveal the decisive role of the tissue stroma in the regulation of macrophage function. These findings suggest that most macrophages seed the tissues during embryonic development and functionally specialize in response to cytokines and metabolites that are released by the stroma and drive the expression of unique transcription factors. In this Review, we discuss how recent insights into macrophage ontogeny and macrophage–stroma interactions contribute to our understanding of the crosstalk that shapes macrophage function and the maintenance of organ integrity. PMID:26603899

Rac1 Regulates Endometrial Secretory Function to Control Placental Development

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Davila, Juanmahel; Laws, Mary J.; Kannan, Athilakshmi; Li, Quanxi; Taylor, Robert N.; Bagchi, Milan K.; Bagchi, Indrani C.

2015-01-01

During placenta development, a succession of complex molecular and cellular interactions between the maternal endometrium and the developing embryo ensures reproductive success. The precise mechanisms regulating this maternal-fetal crosstalk remain unknown. Our study revealed that the expression of Rac1, a member of the Rho family of GTPases, is markedly elevated in mouse decidua on days 7 and 8 of gestation. To investigate its function in the uterus, we created mice bearing a conditional deletion of the Rac1 gene in uterine stromal cells. Ablation of Rac1 did not affect the formation of the decidua but led to fetal loss in mid gestation accompanied by extensive hemorrhage. To gain insights into the molecular pathways affected by the loss of Rac1, we performed gene expression profiling which revealed that Rac1 signaling regulates the expression of Rab27b, another GTPase that plays a key role in targeting vesicular trafficking. Consequently, the Rac1-null decidual cells failed to secrete vascular endothelial growth factor A, which is a critical regulator of decidual angiogenesis, and insulin-like growth factor binding protein 4, which regulates the bioavailability of insulin-like growth factors that promote proliferation and differentiation of trophoblast cell lineages in the ectoplacental cone. The lack of secretion of these key factors by Rac1-null decidua gave rise to impaired angiogenesis and dysregulated proliferation of trophoblast cells, which in turn results in overexpansion of the trophoblast giant cell lineage and disorganized placenta development. Further experiments revealed that RAC1, the human ortholog of Rac1, regulates the secretory activity of human endometrial stromal cells during decidualization, supporting the concept that this signaling G protein plays a central and conserved role in controlling endometrial secretory function. This study provides unique insights into the molecular mechanisms regulating endometrial secretions that mediate stromal

Rac1 Regulates Endometrial Secretory Function to Control Placental Development.

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Juanmahel Davila

2015-08-01

Full Text Available During placenta development, a succession of complex molecular and cellular interactions between the maternal endometrium and the developing embryo ensures reproductive success. The precise mechanisms regulating this maternal-fetal crosstalk remain unknown. Our study revealed that the expression of Rac1, a member of the Rho family of GTPases, is markedly elevated in mouse decidua on days 7 and 8 of gestation. To investigate its function in the uterus, we created mice bearing a conditional deletion of the Rac1 gene in uterine stromal cells. Ablation of Rac1 did not affect the formation of the decidua but led to fetal loss in mid gestation accompanied by extensive hemorrhage. To gain insights into the molecular pathways affected by the loss of Rac1, we performed gene expression profiling which revealed that Rac1 signaling regulates the expression of Rab27b, another GTPase that plays a key role in targeting vesicular trafficking. Consequently, the Rac1-null decidual cells failed to secrete vascular endothelial growth factor A, which is a critical regulator of decidual angiogenesis, and insulin-like growth factor binding protein 4, which regulates the bioavailability of insulin-like growth factors that promote proliferation and differentiation of trophoblast cell lineages in the ectoplacental cone. The lack of secretion of these key factors by Rac1-null decidua gave rise to impaired angiogenesis and dysregulated proliferation of trophoblast cells, which in turn results in overexpansion of the trophoblast giant cell lineage and disorganized placenta development. Further experiments revealed that RAC1, the human ortholog of Rac1, regulates the secretory activity of human endometrial stromal cells during decidualization, supporting the concept that this signaling G protein plays a central and conserved role in controlling endometrial secretory function. This study provides unique insights into the molecular mechanisms regulating endometrial secretions

Regulation of Arabidopsis Early Anther Development by Putative Cell-Cell Signaling Molecules and Transcriptional Regulators

Institute of Scientific and Technical Information of China (English)

Yu-Jin Sun; Carey LH Hord; Chang-Bin Chen; Hong Ma

2007-01-01

Anther development in flowering plants involves the formation of several cell types, including the tapetal and pollen mother cells. The use of genetic and molecular tools has led to the identification and characterization of genes that are critical for normal cell division and differentiation in Arabidopsis early anther development. We review here several recent studies on these genes, including the demonstration that the putative receptor protein kinases BAM1 and BAM2 together play essential roles in the control of early cell division and differentiation. In addition, we discuss the hypothesis that BAM1/2 may form a positive-negative feedback regulatory loop with a previously identified key regulator, SPOROCYTELESS (also called NOZZLE),to control the balance between sporogenous and somatic cell types in the anther. Furthermore, we summarize the isolation and functional analysis of the DYSFUNCTIONAL TAPETUM1 (DYT1) gene in promoting proper tapetal cell differentiation. Our finding that DYT1 encodes a putative transcription factor of the bHLH family, as well as relevant expression analyses, strongly supports a model that DYT1 serves as a critical link between upstream factors and downstream target genes that are critical for normal tapetum development and function. These studies, together with other recently published works, indicate that cell-cell communication and transcriptional control are key processes essential for cell fate specification in anther development.

A balance of FGF and BMP signals regulates cell cycle exit and Equarin expression in lens cells

Science.gov (United States)

Jarrin, Miguel; Pandit, Tanushree; Gunhaga, Lena

2012-01-01

In embryonic and adult lenses, a balance of cell proliferation, cell cycle exit, and differentiation is necessary to maintain physical function. The molecular mechanisms regulating the transition of proliferating lens epithelial cells to differentiated primary lens fiber cells are poorly characterized. To investigate this question, we used gain- and loss-of-function analyses to modulate fibroblast growth factor (FGF) and/or bone morphogenetic protein (BMP) signals in chick lens/retina explants. Here we show that FGF activity plays a key role for proliferation independent of BMP signals. Moreover, a balance of FGF and BMP signals regulates cell cycle exit and the expression of Ccdc80 (also called Equarin), which is expressed at sites where differentiation of lens fiber cells occurs. BMP activity promotes cell cycle exit and induces Equarin expression in an FGF-dependent manner. In contrast, FGF activity is required but not sufficient to induce cell cycle exit or Equarin expression. Furthermore, our results show that in the absence of BMP activity, lens cells have increased cell cycle length or are arrested in the cell cycle, which leads to decreased cell cycle exit. Taken together, these findings suggest that proliferation, cell cycle exit, and early differentiation of primary lens fiber cells are regulated by counterbalancing BMP and FGF signals. PMID:22718906

Electrostatic behavior of the charge-regulated bacterial cell surface.

Science.gov (United States)

Hong, Yongsuk; Brown, Derick G

2008-05-06

The electrostatic behavior of the charge-regulated surfaces of Gram-negative Escherichia coli and Gram-positive Bacillus brevis was studied using numerical modeling in conjunction with potentiometric titration and electrophoretic mobility data as a function of solution pH and electrolyte composition. Assuming a polyelectrolytic polymeric bacterial cell surface, these experimental and numerical analyses were used to determine the effective site numbers of cell surface acid-base functional groups and Ca(2+) sorption coefficients. Using effective site concentrations determined from 1:1 electrolyte (NaCl) experimental data, the charge-regulation model was able to replicate the effects of 2:1 electrolyte (CaCl(2)), both alone and as a mixture with NaCl, on the measured zeta potential using a single Ca(2+) surface binding constant for each of the bacterial species. This knowledge is vital for understanding how cells respond to changes in solution pH and electrolyte composition as well as how they interact with other surfaces. The latter is especially important due to the widespread use of the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory in the interpretation of bacterial adhesion. As surface charge and surface potential both vary on a charge-regulated surface, accurate modeling of bacterial interactions with surfaces ultimately requires use of an electrostatic model that accounts for the charge-regulated nature of the cell surface.

Calcitonin gene-related peptide regulates type IV hypersensitivity through dendritic cell functions.

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Norihisa Mikami

Full Text Available Dendritic cells (DCs play essential roles in both innate and adaptive immune responses. In addition, mutual regulation of the nervous system and immune system is well studied. One of neuropeptides, calcitonin gene-related peptide (CGRP, is a potent regulator in immune responses; in particular, it has anti-inflammatory effects in innate immunity. For instance, a deficiency of the CGRP receptor component RAMP 1 (receptor activity-modifying protein 1 results in higher cytokine production in response to LPS (lipopolysaccharide. On the other hand, how CGRP affects DCs in adaptive immunity is largely unknown. In this study, we show that CGRP suppressed Th1 cell differentiation via inhibition of IL-12 production in DCs using an in vitro co-culture system and an in vivo ovalbumin-induced delayed-type hypersensitivity (DTH model. CGRP also down-regulated the expressions of chemokine receptor CCR2 and its ligands CCL2 and CCL12 in DCs. Intriguingly, the frequency of migrating CCR2(+ DCs in draining lymph nodes of RAMP1-deficient mice was higher after DTH immunization. Moreover, these CCR2(+ DCs highly expressed IL-12 and CD80, resulting in more effective induction of Th1 differentiation compared with CCR2(- DCs. These results indicate that CGRP regulates Th1 type reactions by regulating expression of cytokines, chemokines, and chemokine receptors in DCs.

Protein kinase C signaling and cell cycle regulation

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Adrian R Black

2013-01-01

Full Text Available A link between T cell proliferation and the protein kinase C (PKC family of serine/threonine kinases has been recognized for about thirty years. However, despite the wealth of information on PKC-mediated control of T cell activation, understanding of the effects of PKCs on the cell cycle machinery in this cell type remains limited. Studies in other systems have revealed important cell cycle-specific effects of PKC signaling that can either positively or negatively impact proliferation. The outcome of PKC activation is highly context-dependent, with the precise cell cycle target(s and overall effects determined by the specific isozyme involved, the timing of PKC activation, the cell type, and the signaling environment. Although PKCs can regulate all stages of the cell cycle, they appear to predominantly affect G0/G1 and G2. PKCs can modulate multiple cell cycle regulatory molecules, including cyclins, cyclin-dependent kinases (cdks, cdk inhibitors and cdc25 phosphatases; however, evidence points to Cip/Kip cdk inhibitors and D-type cyclins as key mediators of PKC-regulated cell cycle-specific effects. Several PKC isozymes can target Cip/Kip proteins to control G0/G1→S and/or G2→M transit, while effects on D-type cyclins regulate entry into and progression through G1. Analysis of PKC signaling in T cells has largely focused on its roles in T cell activation; thus, observed cell cycle effects are mainly positive. A prominent role is emerging for PKCθ, with non-redundant functions of other isozymes also described. Additional evidence points to PKCδ as a negative regulator of the cell cycle in these cells. As in other cell types, context-dependent effects of individual isozymes have been noted in T cells, and Cip/Kip cdk inhibitors and D-type cyclins appear to be major PKC targets. Future studies are anticipated to take advantage of the similarities between these various systems to enhance understanding of PKC-mediated cell cycle regulation in

Functions of TAM RTKs in regulating spermatogenesis and male fertility in mice.

Science.gov (United States)

Chen, Yongmei; Wang, Huizhen; Qi, Nan; Wu, Hui; Xiong, Weipeng; Ma, Jing; Lu, Qingxian; Han, Daishu

2009-10-01

Mice lacking TYRO3, AXL and MER (TAM) receptor tyrosine kinases (RTKs) are male sterile. The mechanism of TAM RTKs in regulating male fertility remains unknown. In this study, we analyzed in more detail the testicular phenotype of TAM triple mutant (TAM(-/-)) mice with an effort to understand the mechanism. We demonstrate that the three TAM RTKs cooperatively regulate male fertility, and MER appears to be more important than AXL and TYRO3. TAM(-/-) testes showed a progressive loss of germ cells from elongated spermatids to spermatogonia. Young adult TAM(-/-) mice exhibited oligo-astheno-teratozoospermia and various morphological malformations of sperm cells. As the mice aged, the germ cells were eventually depleted from the seminiferous tubules. Furthermore, we found that TAM(-/-) Sertoli cells have an impaired phagocytic activity and a large number of differentially expressed genes compared to wild-type controls. By contrast, the function of Leydig cells was not apparently affected by the mutation of TAM RTKs. Therefore, we conclude that the suboptimal function of Sertoli cells leads to the impaired spermatogenesis in TAM(-/-) mice. The results provide novel insight into the mechanism of TAM RTKs in regulating male fertility.

Developmental and Functional Control of Natural Killer Cells by Cytokines

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Yang Wu

2017-08-01

Full Text Available Natural killer (NK cells are effective in combating infections and tumors and as such are tempting for adoptive transfer therapy. However, they are not homogeneous but can be divided into three main subsets, including cytotoxic, tolerant, and regulatory NK cells, with disparate phenotypes and functions in diverse tissues. The development and functions of such NK cells are controlled by various cytokines, such as fms-like tyrosine kinase 3 ligand (FL, kit ligand (KL, interleukin (IL-3, IL-10, IL-12, IL-18, transforming growth factor-β, and common-γ chain family cytokines, which operate at different stages by regulating distinct signaling pathways. Nevertheless, the specific roles of each cytokine that regulates NK cell development or that shapes different NK cell functions remain unclear. In this review, we attempt to describe the characteristics of each cytokine and the existing protocols to expand NK cells using different combinations of cytokines and feeder cells. A comprehensive understanding of the role of cytokines in NK cell development and function will aid the generation of better efficacy for adoptive NK cell treatment.

Addition of interferon-alpha to a standard maturation cocktail induces CD38 up-regulation and increases dendritic cell function

DEFF Research Database (Denmark)

Trepiakas, Redas; Pedersen, Anders Elm; Met, Ozcan

2009-01-01

Monocyte-derived dendritic cells (DCs) are used as adjuvant cells in cancer immunotherapy and have shown promising results. In order to obtain full functional capacity, these DCs need to be maturated, and the current "gold standard" for this process is maturation with TNF-alpha, IL-1beta, IL-6...... a functional relationship between CD38, IFN-alpha and TLR3. Thus, CD38 appear to be a relevant marker for activation by TLR3 or IFN-alpha. Addition of IFN-alpha to the sDC cocktail results in up-regulation of both CD38 and CD83 and improved capacity for induction of autologous T-cell responses despite few...... other changes in DC phenotype and cytokine secretion. Our observations suggest that IFN-alpha could be included in maturation protocols for clinical grade DCs used for immunotherapy against cancer and should be included if DCs are used for CD8+ T-cell stimulation in vitro....

Stem cell aging: mechanisms, regulators and therapeutic opportunities

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Oh, Juhyun; Lee, Yang David; Wagers, Amy J

2014-01-01

Aging tissues experience a progressive decline in homeostatic and regenerative capacities, which has been attributed to degenerative changes in tissue-specific stem cells, stem cell niches and systemic cues that regulate stem cell activity. Understanding the molecular pathways involved in this age-dependent deterioration of stem cell function will be critical for developing new therapies for diseases of aging that target the specific causes of age-related functional decline. Here we explore key molecular pathways that are commonly perturbed as tissues and stem cells age and degenerate. We further consider experimental evidence both supporting and refuting the notion that modulation of these pathways per se can reverse aging phenotypes. Finally, we ask whether stem cell aging establishes an epigenetic ‘memory’ that is indelibly written or one that can be reset. PMID:25100532

Hydrogen peroxide production regulates the mitochondrial function in insulin resistant muscle cells: effect of catalase overexpression.

Science.gov (United States)

Barbosa, Marina R; Sampaio, Igor H; Teodoro, Bruno G; Sousa, Thais A; Zoppi, Claudio C; Queiroz, André L; Passos, Madla A; Alberici, Luciane C; Teixeira, Felipe R; Manfiolli, Adriana O; Batista, Thiago M; Cappelli, Ana Paula Gameiro; Reis, Rosana I; Frasson, Danúbia; Kettelhut, Isis C; Parreiras-e-Silva, Lucas T; Costa-Neto, Claudio M; Carneiro, Everardo M; Curi, Rui; Silveira, Leonardo R

2013-10-01

The mitochondrial redox state plays a central role in the link between mitochondrial overloading and insulin resistance. However, the mechanism by which the ROS induce insulin resistance in skeletal muscle cells is not completely understood. We examined the association between mitochondrial function and H2O2 production in insulin resistant cells. Our hypothesis is that the low mitochondrial oxygen consumption leads to elevated ROS production by a mechanism associated with reduced PGC1α transcription and low content of phosphorylated CREB. The cells were transfected with either the encoded sequence for catalase overexpression or the specific siRNA for catalase inhibition. After transfection, myotubes were incubated with palmitic acid (500μM) and the insulin response, as well as mitochondrial function and fatty acid metabolism, was determined. The low mitochondrial oxygen consumption led to elevated ROS production by a mechanism associated with β-oxidation of fatty acids. Rotenone was observed to reduce the ratio of ROS production. The elevated H2O2 production markedly decreased the PGC1α transcription, an effect that was accompanied by a reduced phosphorylation of Akt and CREB. The catalase transfection prevented the reduction in the phosphorylated level of Akt and upregulated the levels of phosphorylated CREB. The mitochondrial function was elevated and H2O2 production reduced, thus increasing the insulin sensitivity. The catalase overexpression improved mitochondrial respiration protecting the cells from fatty acid-induced, insulin resistance. This effect indicates that control of hydrogen peroxide production regulates the mitochondrial respiration preventing the insulin resistance in skeletal muscle cells by a mechanism associated with CREB phosphorylation and β-oxidation of fatty acids. Copyright © 2013 Elsevier B.V. All rights reserved.

Znhit1 causes cell cycle arrest and down-regulates CDK6 expression

International Nuclear Information System (INIS)

Yang, Zhengmin; Cao, Yonghao; Zhu, Xiaoyan; Huang, Ying; Ding, Yuqiang; Liu, Xiaolong

2009-01-01

Cyclin-dependent kinase 6 (CDK6) is the key element of the D-type cyclin holoenzymes which has been found to function in the regulation of G1-phase of the cell cycle and is presumed to play important roles in T cell function. In this study, Znhit1, a member of a new zinc finger protein family defined by a conserved Zf-HIT domain, induced arrest in the G1-phase of the cell cycle in NIH/3T3 cells. Of the G1 cell cycle factors examined, the expression of CDK6 was found to be strongly down-regulated by Znhit1 via transcriptional repression. This effect may have correlations with the decreased acetylation level of histone H4 in the CDK6 promoter region. In addition, considering that CDK6 expression predominates in T cells, the negative regulatory role of Znhit1 in TCR-induced T cell proliferation was validated using transgenic mice. These findings identified Znhit1 as a CDK6 regulator that plays an important role in cell proliferation.

Extracellular Matrix as a Regulator of Epidermal Stem Cell Fate.

Science.gov (United States)

Chermnykh, Elina; Kalabusheva, Ekaterina; Vorotelyak, Ekaterina

2018-03-27

Epidermal stem cells reside within the specific anatomic location, called niche, which is a microenvironment that interacts with stem cells to regulate their fate. Regulation of many important processes, including maintenance of stem cell quiescence, self-renewal, and homeostasis, as well as the regulation of division and differentiation, are common functions of the stem cell niche. As it was shown in multiple studies, extracellular matrix (ECM) contributes a lot to stem cell niches in various tissues, including that of skin. In epidermis, ECM is represented, primarily, by a highly specialized ECM structure, basement membrane (BM), which separates the epidermal and dermal compartments. Epidermal stem cells contact with BM, but when they lose the contact and migrate to the overlying layers, they undergo terminal differentiation. When considering all of these factors, ECM is of fundamental importance in regulating epidermal stem cells maintenance, proper mobilization, and differentiation. Here, we summarize the remarkable progress that has recently been made in the research of ECM role in regulating epidermal stem cell fate, paying special attention to the hair follicle stem cell niche. We show that the destruction of ECM components impairs epidermal stem cell morphogenesis and homeostasis. A deep understanding of ECM molecular structure as well as the development of in vitro system for stem cell maintaining by ECM proteins may bring us to developing new approaches for regenerative medicine.

Leading research on cell proliferation regulation technology; Saibo zoshoku seigyo gijutsu no sendo kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

For developing intelligent material, animal test alternative model, bio-cell analysis equipment, self-controlling bio-reactor and medical material, development of functional cells was studied by cell proliferation regulation technology. In fiscal 1996, the expression analysis and separation technology of specific gene for cell proliferation, and the intracellular regulation technology were surveyed from the viewpoint of intracellular regulation. The cell proliferation regulation technology by specific regulating material of cells, extracellular matrix, coculture system and embryonic cell was surveyed from the viewpoint of extracellular regulation. In addition, based on these survey results, new cell culture/analysis technology, new bio-material, artificial organ system, energy saving bio-reactor, environment purification microorganism, and animal test alternative model were surveyed as applications to industrial basic technologies from a long-term viewpoint. The approach to cell proliferation regulation requires preparation of a concrete proliferation regulation technology system of cells, and concrete application targets. 268 refs., 43 figs., 4 tabs.

Phosphorylation of Large T Antigen Regulates Merkel Cell Polyomavirus Replication

International Nuclear Information System (INIS)

Diaz, Jason; Wang, Xin; Tsang, Sabrina H.; Jiao, Jing; You, Jianxin

2014-01-01

Merkel Cell Polyomavirus (MCPyV) was recently discovered as a novel human polyomavirus that is associated with ~80% of Merkel Cell Carcinomas. The Large Tumor antigen (LT) is an early viral protein which has a variety of functions, including manipulation of the cell cycle and initiating viral DNA replication. Phosphorylation plays a critical regulatory role for polyomavirus LT proteins, but no investigation of MCPyV LT phosphorylation has been performed to date. In this report mass spectrometry analysis reveals three unique phosphorylation sites: T271, T297 and T299. In vivo replication assays confirm that phosphorylation of T271 does not play a role in viral replication, while modification at T297 and T299 have dramatic and opposing effects on LT’s ability to initiate replication from the viral origin. We test these mutants for their ability to bind, unwind, and act as a functional helicase at the viral origin. These studies provide a framework for understanding how phosphorylation of LT may dynamically regulate viral replication. Although the natural host cell of MCPyV has not yet been established, this work provides a foundation for understanding how LT activity is regulated and provides tools for better exploring this regulation in both natural host cells and Merkel cells

Phosphorylation of Large T Antigen Regulates Merkel Cell Polyomavirus Replication

Energy Technology Data Exchange (ETDEWEB)

Diaz, Jason; Wang, Xin; Tsang, Sabrina H. [Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104 (United States); Jiao, Jing [Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104 (United States); You, Jianxin, E-mail: jianyou@mail.med.upenn.edu [Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104 (United States)

2014-07-08

Merkel Cell Polyomavirus (MCPyV) was recently discovered as a novel human polyomavirus that is associated with ~80% of Merkel Cell Carcinomas. The Large Tumor antigen (LT) is an early viral protein which has a variety of functions, including manipulation of the cell cycle and initiating viral DNA replication. Phosphorylation plays a critical regulatory role for polyomavirus LT proteins, but no investigation of MCPyV LT phosphorylation has been performed to date. In this report mass spectrometry analysis reveals three unique phosphorylation sites: T271, T297 and T299. In vivo replication assays confirm that phosphorylation of T271 does not play a role in viral replication, while modification at T297 and T299 have dramatic and opposing effects on LT’s ability to initiate replication from the viral origin. We test these mutants for their ability to bind, unwind, and act as a functional helicase at the viral origin. These studies provide a framework for understanding how phosphorylation of LT may dynamically regulate viral replication. Although the natural host cell of MCPyV has not yet been established, this work provides a foundation for understanding how LT activity is regulated and provides tools for better exploring this regulation in both natural host cells and Merkel cells.

Regulation of beta cell replication

DEFF Research Database (Denmark)

Lee, Ying C; Nielsen, Jens Høiriis

2008-01-01

Beta cell mass, at any given time, is governed by cell differentiation, neogenesis, increased or decreased cell size (cell hypertrophy or atrophy), cell death (apoptosis), and beta cell proliferation. Nutrients, hormones and growth factors coupled with their signalling intermediates have been...... suggested to play a role in beta cell mass regulation. In addition, genetic mouse model studies have indicated that cyclins and cyclin-dependent kinases that determine cell cycle progression are involved in beta cell replication, and more recently, menin in association with cyclin-dependent kinase...... inhibitors has been demonstrated to be important in beta cell growth. In this review, we consider and highlight some aspects of cell cycle regulation in relation to beta cell replication. The role of cell cycle regulation in beta cell replication is mostly from studies in rodent models, but whether...

Development, regulation, metabolism and function of bone marrow adipose tissues.

Science.gov (United States)

Li, Ziru; Hardij, Julie; Bagchi, Devika P; Scheller, Erica L; MacDougald, Ormond A

2018-05-01

Most adipocytes exist in discrete depots throughout the body, notably in well-defined white and brown adipose tissues. However, adipocytes also reside within specialized niches, of which the most abundant is within bone marrow. Whereas bone marrow adipose tissue (BMAT) shares many properties in common with white adipose tissue, the distinct functions of BMAT are reflected by its development, regulation, protein secretion, and lipid composition. In addition to its potential role as a local energy reservoir, BMAT also secretes proteins, including adiponectin, RANK ligand, dipeptidyl peptidase-4, and stem cell factor, which contribute to local marrow niche functions and which may also influence global metabolism. The characteristics of BMAT are also distinct depending on whether marrow adipocytes are contained within yellow or red marrow, as these can be thought of as 'constitutive' and 'regulated', respectively. The rBMAT for instance can be expanded or depleted by myriad factors, including age, nutrition, endocrine status and pharmaceuticals. Herein we review the site specificity, age-related development, regulation and metabolic characteristics of BMAT under various metabolic conditions, including the functional interactions with bone and hematopoietic cells. Copyright © 2018 Elsevier Inc. All rights reserved.

Cell volume regulation: physiology and pathophysiology

DEFF Research Database (Denmark)

Lambert, I H; Hoffmann, E K; Pedersen, Stine Helene Falsig

2008-01-01

are sensed are still far from clear, significant progress has been made with respect to the nature of the sensors, transducers and effectors that convert a change in cell volume into a physiological response. In the present review, we summarize recent major developments in the field, and emphasize......Cell volume perturbation initiates a wide array of intracellular signalling cascades, leading to protective and adaptive events and, in most cases, activation of volume-regulatory osmolyte transport, water loss, and hence restoration of cell volume and cellular function. Cell volume is challenged....../hypernatremia. On the other hand, it has recently become clear that an increase or reduction in cell volume can also serve as a specific signal in the regulation of physiological processes such as transepithelial transport, cell migration, proliferation and death. Although the mechanisms by which cell volume perturbations...

Receptor-type Protein Tyrosine Phosphatase β Regulates Met Phosphorylation and Function in Head and Neck Squamous Cell Carcinoma

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Yiru Xu

2012-11-01

Full Text Available Head and neck squamous cell carcinoma (HNSCC is the sixth most common cancer and has a high rate of mortality. Emerging evidence indicates that hepatocyte growth factor receptor (or Met pathway plays a pivotal role in HNSCC metastasis and resistance to chemotherapy. Met function is dependent on tyrosine phosphorylation that is under direct control by receptor-type protein tyrosine phosphatase β (RPTP-β. We report here that RPTP-β expression is significantly downregulated in HNSCC cells derived from metastatic tumors compared to subject-matched cells from primary tumors. Knockdown of endogenous RPTP-β in HNSCC cells from primary tumor potentiated Met tyrosine phosphorylation, downstream mitogen-activated protein (MAP kinase pathway activation, cell migration, and invasion. Conversely, restoration of RPTP-β expression in cells from matched metastatic tumor decreased Met tyrosine phosphorylation and downstream functions. Furthermore, we observed that six of eight HNSCC tumors had reduced levels of RPTP-β protein in comparison with normal oral tissues. Collectively, the results demonstrate the importance of RPTP-β in tumor biology of HNSCC through direct dephosphorylation of Met and regulation of downstream signal transduction pathways. Reduced RPTP-β levels, with or without Met overexpression, could promote Met activation in HNSCC tumors.

Mitochondria-Associated Membranes As Networking Platforms and Regulators of Cancer Cell Fate

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Maria Livia Sassano

2017-08-01

Full Text Available The tight cross talk between two essential organelles of the cell, the endoplasmic reticulum (ER and mitochondria, is spatially and functionally regulated by specific microdomains known as the mitochondria-associated membranes (MAMs. MAMs are hot spots of Ca2+ transfer between the ER and mitochondria, and emerging data indicate their vital role in the regulation of fundamental physiological processes, chief among them mitochondria bioenergetics, proteostasis, cell death, and autophagy. Moreover, and perhaps not surprisingly, it has become clear that signaling events regulated at the ER–mitochondria intersection regulate key processes in oncogenesis and in the response of cancer cells to therapeutics. ER–mitochondria appositions have been shown to dynamically recruit oncogenes and tumor suppressors, modulating their activity and protein complex formation, adapt the bioenergetic demand of cancer cells and to regulate cell death pathways and redox signaling in cancer cells. In this review, we discuss some emerging players of the ER–mitochondria contact sites in mammalian cells, the key processes they regulate and recent evidence highlighting the role of MAMs in shaping cell-autonomous and non-autonomous signals that regulate cancer growth.

Regulation of FOXO1-mediated transcription and cell proliferation by PARP-1

Energy Technology Data Exchange (ETDEWEB)

Sakamaki, Jun-ichi; Daitoku, Hiroaki; Yoshimochi, Kenji [Center for Tsukuba Advanced Research Alliance, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Miwa, Masanao [Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526-0829 (Japan); Fukamizu, Akiyoshi, E-mail: akif@tara.tsukuba.ac.jp [Center for Tsukuba Advanced Research Alliance, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan)

2009-05-08

Forkhead box O (FOXO) transcription factors play an important role in a wide range of biological processes, including cell cycle control, apoptosis, detoxification of reactive oxygen species, and gluconeogenesis through regulation of gene expression. In this study, we demonstrated that PARP-1 functions as a negative regulator of FOXO1. We showed that PARP-1 directly binds to and poly(ADP-ribosyl)ates FOXO1 protein. PARP-1 represses FOXO1-mediated expression of cell cycle inhibitor p27{sup Kip1} gene. Notably, poly(ADP-ribosyl)ation activity was not required for the repressive effect of PARP-1 on FOXO1 function. Furthermore, knockdown of PARP-1 led to a decrease in cell proliferation in a manner dependent on FOXO1 function. Chromatin immunoprecipitation experiments confirmed that PARP-1 is recruited to the p27{sup Kip1} gene promoter through a binding to FOXO1. These results suggest that PARP-1 acts as a corepressor for FOXO1, which could play an important role in proper cell proliferation by regulating p27{sup Kip1} gene expression.

Membrane elastic properties and cell function.

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Bruno Pontes

Full Text Available Recent studies indicate that the cell membrane, interacting with its attached cytoskeleton, is an important regulator of cell function, exerting and responding to forces. We investigate this relationship by looking for connections between cell membrane elastic properties, especially surface tension and bending modulus, and cell function. Those properties are measured by pulling tethers from the cell membrane with optical tweezers. Their values are determined for all major cell types of the central nervous system, as well as for macrophage. Astrocytes and glioblastoma cells, which are considerably more dynamic than neurons, have substantially larger surface tensions. Resting microglia, which continually scan their environment through motility and protrusions, have the highest elastic constants, with values similar to those for resting macrophage. For both microglia and macrophage, we find a sharp softening of bending modulus between their resting and activated forms, which is very advantageous for their acquisition of phagocytic functions upon activation. We also determine the elastic constants of pure cell membrane, with no attached cytoskeleton. For all cell types, the presence of F-actin within tethers, contrary to conventional wisdom, is confirmed. Our findings suggest the existence of a close connection between membrane elastic constants and cell function.

Cell volume regulation in epithelial physiology and cancer

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Pedersen, Stine Helene Falsig; Hoffmann, Else Kay; Novak, Ivana

2013-01-01

expression of ion transporters and channels is now recognized as one of the hallmarks of cancer, it is timely to consider this especially for epithelia. Epithelial cells are highly proliferative and epithelial cancers, carcinomas, account for about 90% of all cancers. In this review we will focus on ion...... such as cancer, transepithelial and cell volume regulatory ion transport are dys-regulated. Furthermore, epithelial architecture and coordinated ion transport function are lost, cell survival/death balance is altered, and new interactions with the stroma arise, all contributing to drug resistance. Since altered...... transporters and channels with key physiological functions in epithelia and known roles in the development of cancer in these tissues. Their roles in cell survival, cell cycle progression, and development of drug resistance in epithelial cancers will be discussed....

Phenotypic and functional plasticity of cells of innate immunity: macrophages, mast cells and neutrophils

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Galli, Stephen J; Borregaard, Niels; Wynn, Thomas A

2011-01-01

Hematopoietic cells, including lymphoid and myeloid cells, can develop into phenotypically distinct 'subpopulations' with different functions. However, evidence indicates that some of these subpopulations can manifest substantial plasticity (that is, undergo changes in their phenotype and function......). Here we focus on the occurrence of phenotypically distinct subpopulations in three lineages of myeloid cells with important roles in innate and acquired immunity: macrophages, mast cells and neutrophils. Cytokine signals, epigenetic modifications and other microenvironmental factors can substantially...... and, in some cases, rapidly and reversibly alter the phenotype of these cells and influence their function. This suggests that regulation of the phenotype and function of differentiated hematopoietic cells by microenvironmental factors, including those generated during immune responses, represents...

Phenotypic and functional plasticity of cells of innate immunity: macrophages, mast cells and neutrophils

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Galli, Stephen J; Borregaard, Niels; Wynn, Thomas A

2011-01-01

). Here we focus on the occurrence of phenotypically distinct subpopulations in three lineages of myeloid cells with important roles in innate and acquired immunity: macrophages, mast cells and neutrophils. Cytokine signals, epigenetic modifications and other microenvironmental factors can substantially......Hematopoietic cells, including lymphoid and myeloid cells, can develop into phenotypically distinct 'subpopulations' with different functions. However, evidence indicates that some of these subpopulations can manifest substantial plasticity (that is, undergo changes in their phenotype and function...... and, in some cases, rapidly and reversibly alter the phenotype of these cells and influence their function. This suggests that regulation of the phenotype and function of differentiated hematopoietic cells by microenvironmental factors, including those generated during immune responses, represents...

Expression of FLNa in human melanoma cells regulates the function of integrin α1β1 and phosphorylation and localisation of PKB/AKT/ERK1/2 kinases.

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Krebs, Kristi; Ruusmann, Anu; Simonlatser, Grethel; Velling, Teet

2015-12-01

FLNa is a ubiquitous cytoskeletal protein that links transmembrane receptors, including integrins, to F-actin and functions as a signalling intermediate. We investigated FLNa's role in the function of integrin-type collagen receptors, EGF-EGFR signalling and regulation of PKB/Akt and ERK1/2. Using FLNa-deficient M2 human melanoma cells, and same cells expressing EGFP-FLNa (M2F) or its Ig-like repeats 1-8+24, 8-15+24 and 16-24, we found that in M2F and M2 8-15+24 cells, EGF induced the increased phosphorylation of PKB/Akt and ERK1/2. In M2F cells EGF induced the localisation of these kinases to cell nucleus and lamellipodia, respectively, and the ERK1/2 phosphorylation-dependent co-immunoprecipitation of FLNa with ERK1/2. Only M2F and M2 8-15+24 cells adhered to and spread on type I collagen whereas on fibronectin all cells behaved similarly. α1β1 and α2β1 were the integrin-type collagen receptors expressed on these cells with primarily α1β1 localising to focal contacts and affecting cell adhesion and migration in a manner dependent on FLNa or its Ig-like repeats 8-15. Our results suggest a role for FLNa repeats 8-15 in the α1-subunit-dependent regulation of integrin α1β1 function, EGF-EGFR signalling to PKB/Akt and ERK1/2, identify ERK1/2 in EGF-induced FLNa-associated protein complexes, and show that the function of different integrins is subjected to differential regulation by FLNa. Copyright © 2015. Published by Elsevier GmbH.

The Fas pathway is involved in pancreatic beta cell secretory function

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Schumann, Desiree M; Maedler, Kathrin; Franklin, Isobel

2007-01-01

Pancreatic beta cell mass and function increase in conditions of enhanced insulin demand such as obesity. Failure to adapt leads to diabetes. The molecular mechanisms controlling this adaptive process are unclear. Fas is a death receptor involved in beta cell apoptosis or proliferation, depending...... on the activity of the caspase-8 inhibitor FLIP. Here we show that the Fas pathway also regulates beta cell secretory function. We observed impaired glucose tolerance in Fas-deficient mice due to a delayed and decreased insulin secretory pattern. Expression of PDX-1, a beta cell-specific transcription factor...... regulating insulin gene expression and mitochondrial metabolism, was decreased in Fas-deficient beta cells. As a consequence, insulin and ATP production were severely reduced and only partly compensated for by increased beta cell mass. Up-regulation of FLIP enhanced NF-kappaB activity via NF...

Drak2 Does Not Regulate TGF-β Signaling in T Cells.

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Tarsha L Harris

Full Text Available Drak2 is a serine/threonine kinase expressed highest in T cells and B cells. Drak2-/- mice are resistant to autoimmunity in mouse models of type 1 diabetes and multiple sclerosis. Resistance to these diseases occurs, in part, because Drak2 is required for the survival of autoreactive T cells that induce disease. However, the molecular mechanisms by which Drak2 affects T cell survival and autoimmunity are not known. A recent report demonstrated that Drak2 negatively regulated transforming growth factor-β (TGF-β signaling in tumor cell lines. Thus, increased TGF-β signaling in the absence of Drak2 may contribute to the resistance to autoimmunity in Drak2-/- mice. Therefore, we examined if Drak2 functioned as a negative regulator of TGF-β signaling in T cells, and whether the enhanced susceptibility to death of Drak2-/- T cells was due to augmented TGF-β signaling. Using several in vitro assays to test TGF-β signaling and T cell function, we found that activation of Smad2 and Smad3, which are downstream of the TGF-β receptor, was similar between wildtype and Drak2-/- T cells. Furthermore, TGF-β-mediated effects on naïve T cell proliferation, activated CD8+ T cell survival, and regulatory T cell induction was similar between wildtype and Drak2-/- T cells. Finally, the increased susceptibility to death in the absence of Drak2 was not due to enhanced TGF-β signaling. Together, these data suggest that Drak2 does not function as a negative regulator of TGF-β signaling in primary T cells stimulated in vitro. It is important to investigate and discern potential molecular mechanisms by which Drak2 functions in order to better understand the etiology of autoimmune diseases, as well as to validate the use of Drak2 as a target for therapeutic treatment of these diseases.

Multiple Myeloma-Derived Exosomes Regulate the Functions of Mesenchymal Stem Cells Partially via Modulating miR-21 and miR-146a

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Qian Cheng

2017-01-01

Full Text Available Exosomes derived from cancer cells can affect various functions of mesenchymal stem cells (MSCs via conveying microRNAs (miRs. miR-21 and miR-146a have been demonstrated to regulate MSC proliferation and transformation. Interleukin-6 (IL-6 secreted from transformed MSCs in turn favors the survival of multiple myeloma (MM cells. However, the effects of MM exosomes on MSC functions remain largely unclear. In this study, we investigated the effects of OPM2 (a MM cell line exosomes (OPM2-exo on regulating the proliferation, cancer-associated fibroblast (CAF transformation, and IL-6 secretion of MSCs and determined the role of miR-21 and miR-146a in these effects. We found that OPM2-exo harbored high levels of miR-21 and miR-146a and that OPM2-exo coculture significantly increased MSC proliferation with upregulation of miR-21 and miR-146a. Moreover, OPM2-exo induced CAF transformation of MSCs, which was evidenced by increased fibroblast-activated protein (FAP, α-smooth muscle actin (α-SMA, and stromal-derived factor 1 (SDF-1 expressions and IL-6 secretion. Inhibition of miR-21 or miR-146a reduced these effects of OPM2-exo on MSCs. In conclusion, MM could promote the proliferation, CAF transformation, and IL-6 secretion of MSCs partially through regulating miR21 and miR146a.

Prolonged oxidative stress down-regulates Early B cell factor 1 with inhibition of its tumor suppressive function against cholangiocarcinoma genesis

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Napat Armartmuntree

2018-04-01

Full Text Available Early B cell factor 1 (EBF1 is a transcription factor involved in the differentiation of several stem cell lineages and it is a negative regulator of estrogen receptors. EBF1 is down-regulated in many tumors, and is believed to play suppressive roles in cancer promotion and progression. However, the functional roles of EBF1 in carcinogenesis are unclear. Liver fluke-infection-associated cholangiocarcinoma (CCA is an oxidative stress-driven cancer of bile duct epithelium. In this study, we investigated EBF1 expression in tissues from CCA patients, CCA cell lines (KKU-213, KKU-214 and KKU-156, cholangiocyte (MMNK1 and its oxidative stress-resistant (ox-MMNK1-L cell lines. The formation of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG was used as an oxidative stress marker. Our results revealed that EBF1 expression was suppressed in cancer cells compared with the individual normal bile duct cells at tumor adjacent areas of CCA tissues. CCA patients with low EBF1 expression and high formation of 8-oxodG were shown to correlate with poor survival. Moreover, EBF1 was suppressed in the oxidative stress-resistant cell line and all of CCA cell lines compared to the cholangiocyte cell line. This suggests that prolonged oxidative stress suppressed EBF1 expression and the reduced EBF1 level may facilitate CCA genesis. To elucidate the significance of EBF1 suppression in CCA genesis, EBF1 expression of the MMNK1 cell line was down-regulated by siRNA technique, and its effects on stem cell properties (CD133 and Oct3/4 expressions, tumorigenic properties (cell proliferation, wound healing and cell migration, estrogen responsive gene (TFF1, estrogen-stimulated wound healing, and cell migration were examined. The results showed that CD133, Oct3/4 and TFF1 expression levels, wound healing, and cell migration of EBF1 knockdown-MMNK1 cells were significantly increased. Also, cell migration of EBF1-knockdown cells was significantly enhanced after 17�

Gene function in early mouse embryonic stem cell differentiation

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Campbell Pearl A

2007-03-01

Full Text Available Abstract Background Little is known about the genes that drive embryonic stem cell differentiation. However, such knowledge is necessary if we are to exploit the therapeutic potential of stem cells. To uncover the genetic determinants of mouse embryonic stem cell (mESC differentiation, we have generated and analyzed 11-point time-series of DNA microarray data for three biologically equivalent but genetically distinct mESC lines (R1, J1, and V6.5 undergoing undirected differentiation into embryoid bodies (EBs over a period of two weeks. Results We identified the initial 12 hour period as reflecting the early stages of mESC differentiation and studied probe sets showing consistent changes of gene expression in that period. Gene function analysis indicated significant up-regulation of genes related to regulation of transcription and mRNA splicing, and down-regulation of genes related to intracellular signaling. Phylogenetic analysis indicated that the genes showing the largest expression changes were more likely to have originated in metazoans. The probe sets with the most consistent gene changes in the three cell lines represented 24 down-regulated and 12 up-regulated genes, all with closely related human homologues. Whereas some of these genes are known to be involved in embryonic developmental processes (e.g. Klf4, Otx2, Smn1, Socs3, Tagln, Tdgf1, our analysis points to others (such as transcription factor Phf21a, extracellular matrix related Lama1 and Cyr61, or endoplasmic reticulum related Sc4mol and Scd2 that have not been previously related to mESC function. The majority of identified functions were related to transcriptional regulation, intracellular signaling, and cytoskeleton. Genes involved in other cellular functions important in ESC differentiation such as chromatin remodeling and transmembrane receptors were not observed in this set. Conclusion Our analysis profiles for the first time gene expression at a very early stage of m

Meis1 regulates Foxn4 expression during retinal progenitor cell differentiation

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Mohammed M. Islam

2013-09-01

The transcription factor forkhead box N4 (Foxn4 is a key regulator in a variety of biological processes during development. In particular, Foxn4 plays an essential role in the genesis of horizontal and amacrine neurons from neural progenitors in the vertebrate retina. Although the functions of Foxn4 have been well established, the transcriptional regulation of Foxn4 expression during progenitor cell differentiation remains unclear. Here, we report that an evolutionarily conserved 129 bp noncoding DNA fragment (Foxn4CR4.2 or CR4.2, located ∼26 kb upstream of Foxn4 transcription start site, functions as a cis-element for Foxn4 regulation. CR4.2 directs gene expression in Foxn4-positive cells, primarily in progenitors, differentiating horizontal and amacrine cells. We further determined that the gene regulatory activity of CR4.2 is modulated by Meis1 binding motif, which is bound and activated by Meis1 transcription factor. Deletion of the Meis1 binding motif or knockdown of Meis1 expression abolishes the gene regulatory activity of CR4.2. In addition, knockdown of Meis1 expression diminishes the endogenous Foxn4 expression and affects cell lineage development. Together, we demonstrate that CR4.2 and its interacting Meis1 transcription factor play important roles in regulating Foxn4 expression during early retinogenesis. These findings provide new insights into molecular mechanisms that govern gene regulation in retinal progenitors and specific cell lineage development.

Myostatin signals through Pax7 to regulate satellite cell self-renewal

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McFarlane, Craig; Hennebry, Alex; Thomas, Mark; Plummer, Erin; Ling, Nicholas; Sharma, Mridula; Kambadur, Ravi

2008-01-01

Myostatin, a Transforming Growth Factor-beta (TGF-β) super-family member, has previously been shown to negatively regulate satellite cell activation and self-renewal. However, to date the mechanism behind Myostatin function in satellite cell biology is not known. Here we show that Myostatin signals via a Pax7-dependent mechanism to regulate satellite cell self-renewal. While excess Myostatin inhibited Pax7 expression via ERK1/2 signaling, an increase in Pax7 expression was observed following both genetic inactivation and functional antagonism of Myostatin. As a result, we show that either blocking or inactivating Myostatin enhances the partitioning of the fusion-incompetent self-renewed satellite cell lineage (high Pax7 expression, low MyoD expression) from the pool of actively proliferating myogenic precursor cells. Consistent with this result, over-expression of Pax7 in C2C12 myogenic cells resulted in increased self-renewal through a mechanism which slowed both myogenic proliferation and differentiation. Taken together, these results suggest that increased expression of Pax7 promotes satellite cell self-renewal, and furthermore Myostatin may control the process of satellite cell self-renewal through regulation of Pax7. Thus we speculate that, in addition to the intrinsic factors (such as Pax7), extrinsic factors both positive and negative in nature, will play a major role in determining the stemness of skeletal muscle satellite cells

Defining the role of mesenchymal stromal cells on the regulation of matrix metalloproteinases in skeletal muscle cells

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Sassoli, Chiara; Nosi, Daniele; Tani, Alessia; Chellini, Flaminia; Mazzanti, Benedetta; Quercioli, Franco; Zecchi-Orlandini, Sandra; Formigli, Lucia

2014-01-01

Recent studies indicate that mesenchymal stromal cell (MSC) transplantation improves healing of injured and diseased skeletal muscle, although the mechanisms of benefit are poorly understood. In the present study, we investigated whether MSCs and/or their trophic factors were able to regulate matrix metalloproteinase (MMP) expression and activity in different cells of the muscle tissue. MSCs in co-culture with C2C12 cells or their conditioned medium (MSC-CM) up-regulated MMP-2 and MMP-9 expression and function in the myoblastic cells; these effects were concomitant with the down-regulation of the tissue inhibitor of metalloproteinases (TIMP)-1 and -2 and with increased cell motility. In the single muscle fiber experiments, MSC-CM administration increased MMP-2/9 expression in Pax-7 + satellite cells and stimulated their mobilization, differentiation and fusion. The anti-fibrotic properties of MSC-CM involved also the regulation of MMPs by skeletal fibroblasts and the inhibition of their differentiation into myofibroblasts. The treatment with SB-3CT, a potent MMP inhibitor, prevented in these cells, the decrease of α-smooth actin and type-I collagen expression induced by MSC-CM, suggesting that MSC-CM could attenuate the fibrogenic response through mechanisms mediated by MMPs. Our results indicate that growth factors and cytokines released by these cells may modulate the fibrotic response and improve the endogenous mechanisms of muscle repair/regeneration. - Highlights: • MSC-CM contains paracrine factors that up-regulate MMP expression and function in different skeletal muscle cells. • MSC-CM promotes myoblast and satellite cell migration, proliferation and differentiation. • MSC-CM negatively interferes with fibroblast-myoblast transition in primary skeletal fibroblasts. • Paracrine factors from MSCs modulate the fibrotic response and improve the endogenous mechanisms of muscle regeneration

Defining the role of mesenchymal stromal cells on the regulation of matrix metalloproteinases in skeletal muscle cells

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Sassoli, Chiara; Nosi, Daniele; Tani, Alessia; Chellini, Flaminia [Dept. of Experimental and Clinical Medicine—Section of Anatomy and Histology, University of Florence, Largo Brambilla, 3, 50134, Florence (Italy); Mazzanti, Benedetta [Dept. of Experimental and Clinical Medicine—Section of Haematology, University of Florence, Largo Brambilla, 3, 50134, Florence (Italy); Quercioli, Franco [CNR-National Institute of Optics (INO), Largo Enrico Fermi 6, 50125 Arcetri-Florence (Italy); Zecchi-Orlandini, Sandra [Dept. of Experimental and Clinical Medicine—Section of Anatomy and Histology, University of Florence, Largo Brambilla, 3, 50134, Florence (Italy); Formigli, Lucia, E-mail: formigli@unifi.it [Dept. of Experimental and Clinical Medicine—Section of Anatomy and Histology, University of Florence, Largo Brambilla, 3, 50134, Florence (Italy)

2014-05-01

Recent studies indicate that mesenchymal stromal cell (MSC) transplantation improves healing of injured and diseased skeletal muscle, although the mechanisms of benefit are poorly understood. In the present study, we investigated whether MSCs and/or their trophic factors were able to regulate matrix metalloproteinase (MMP) expression and activity in different cells of the muscle tissue. MSCs in co-culture with C2C12 cells or their conditioned medium (MSC-CM) up-regulated MMP-2 and MMP-9 expression and function in the myoblastic cells; these effects were concomitant with the down-regulation of the tissue inhibitor of metalloproteinases (TIMP)-1 and -2 and with increased cell motility. In the single muscle fiber experiments, MSC-CM administration increased MMP-2/9 expression in Pax-7{sup +} satellite cells and stimulated their mobilization, differentiation and fusion. The anti-fibrotic properties of MSC-CM involved also the regulation of MMPs by skeletal fibroblasts and the inhibition of their differentiation into myofibroblasts. The treatment with SB-3CT, a potent MMP inhibitor, prevented in these cells, the decrease of α-smooth actin and type-I collagen expression induced by MSC-CM, suggesting that MSC-CM could attenuate the fibrogenic response through mechanisms mediated by MMPs. Our results indicate that growth factors and cytokines released by these cells may modulate the fibrotic response and improve the endogenous mechanisms of muscle repair/regeneration. - Highlights: • MSC-CM contains paracrine factors that up-regulate MMP expression and function in different skeletal muscle cells. • MSC-CM promotes myoblast and satellite cell migration, proliferation and differentiation. • MSC-CM negatively interferes with fibroblast-myoblast transition in primary skeletal fibroblasts. • Paracrine factors from MSCs modulate the fibrotic response and improve the endogenous mechanisms of muscle regeneration.

Cdt1 revisited: complex and tight regulation during the cell cycle and consequences of deregulation in mammalian cells

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Fujita Masatoshi

2006-10-01

Full Text Available Abstract In eukaryotic cells, replication of genomic DNA initiates from multiple replication origins distributed on multiple chromosomes. To ensure that each origin is activated precisely only once during each S phase, a system has evolved which features periodic assembly and disassembly of essential pre-replication complexes (pre-RCs at replication origins. The pre-RC assembly reaction involves the loading of a presumptive replicative helicase, the MCM2-7 complexes, onto chromatin by the origin recognition complex (ORC and two essential factors, CDC6 and Cdt1. The eukaryotic cell cycle is driven by the periodic activation and inactivation of cyclin-dependent kinases (Cdks and assembly of pre-RCs can only occur during the low Cdk activity period from late mitosis through G1 phase, with inappropriate re-assembly suppressed during S, G2, and M phases. It was originally suggested that inhibition of Cdt1 function after S phase in vertebrate cells is due to geminin binding and that Cdt1 hyperfunction resulting from Cdt1-geminin imbalance induces re-replication. However, recent progress has revealed that Cdt1 activity is more strictly regulated by two other mechanisms in addition to geminin: (1 functional and SCFSkp2-mediated proteolytic regulation through phosphorylation by Cdks; and (2 replication-coupled proteolysis mediated by the Cullin4-DDB1Cdt2 ubiquitin ligase and PCNA, an eukaryotic sliding clamp stimulating replicative DNA polymerases. The tight regulation implies that Cdt1 control is especially critical for the regulation of DNA replication in mammalian cells. Indeed, Cdt1 overexpression evokes chromosomal damage even without re-replication. Furthermore, deregulated Cdt1 induces chromosomal instability in normal human cells. Since Cdt1 is overexpressed in cancer cells, this could be a new molecular mechanism leading to carcinogenesis. In this review, recent insights into Cdt1 function and regulation in mammalian cells are discussed.

The microRNA-200 family coordinately regulates cell adhesion and proliferation in hair morphogenesis.

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Hoefert, Jaimee E; Bjerke, Glen A; Wang, Dongmei; Yi, Rui

2018-06-04

The microRNA (miRNA)-200 (miR-200) family is highly expressed in epithelial cells and frequently lost in metastatic cancer. Despite intensive studies into their roles in cancer, their targets and functions in normal epithelial tissues remain unclear. Importantly, it remains unclear how the two subfamilies of the five-miRNA family, distinguished by a single nucleotide within the seed region, regulate their targets. By directly ligating miRNAs to their targeted mRNA regions, we identify numerous miR-200 targets involved in the regulation of focal adhesion, actin cytoskeleton, cell cycle, and Hippo/Yap signaling. The two subfamilies bind to largely distinct target sites, but many genes are coordinately regulated by both subfamilies. Using inducible and knockout mouse models, we show that the miR-200 family regulates cell adhesion and orientation in the hair germ, contributing to precise cell fate specification and hair morphogenesis. Our findings demonstrate that combinatorial targeting of many genes is critical for miRNA function and provide new insights into miR-200's functions. © 2018 Hoefert et al.

Induced pluripotent stem cells-derived myeloid-derived suppressor cells regulate the CD8+ T cell response

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Daniel Joyce

2018-05-01

Full Text Available Myeloid-derived suppressor cells (MDSCs are markedly increased in cancer patients and tumor-bearing mice and promote tumor growth and survival by inhibiting host innate and adaptive immunity. In this study, we generated and characterized MDSCs from murine-induced pluripotent stem cells (iPSCs. The iPSCs were co-cultured with OP9 cells, stimulated with GM-CSF, and became morphologically heterologous under co-culturing with hepatic stellate cells. Allogeneic and OVA-specific antigen stimulation demonstrated that iPS-MDSCs have a T-cell regulatory function. Furthermore, a popliteal lymph node assay and autoimmune hepatitis model showed that iPS-MDSCs also regulate immune responsiveness in vivo and have a therapeutic effect against hepatitis. Taken together, our results demonstrated a method of generating functional MDSCs from iPSCs and highlighted the potential of iPS-MDSCs as a key cell therapy resource for transplantation and autoimmune diseases. Keywords: Myeloid-derived suppressor cells, Induced pluripotent stem cells, T cell response

SAMHD1 is down regulated in lung cancer by methylation and inhibits tumor cell proliferation

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Wang, Jia-lei; Lu, Fan-zhen; Shen, Xiao-Yong; Wu, Yun; Zhao, Li-ting

2014-01-01

Highlights: • SAMHD1 expression level is down regulated in lung adenocarcinoma. • The promoter of SAMHD1 is methylated in lung adenocarcinoma. • Over expression of SAMHD1 inhibits the proliferation of lung cancer cells. - Abstract: The function of dNTP hydrolase SAMHD1 as a viral restriction factor to inhibit the replication of several viruses in human immune cells was well established. However, its regulation and function in lung cancer have been elusive. Here, we report that SAMHD1 is down regulated both on protein and mRNA levels in lung adenocarcinoma compared to adjacent normal tissue. We also found that SAMHD1 promoter is highly methylated in lung adenocarcinoma, which may inhibit its gene expression. Furthermore, over expression of the SAMHD1 reduces dNTP level and inhibits the proliferation of lung tumor cells. These results reveal the regulation and function of SAMHD1 in lung cancer, which is important for the proliferation of lung tumor cells

Function and regulation of LAG3 on CD4+CD25- T cells in non-small cell lung cancer.

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Ma, Qin-Yun; Huang, Da-Yu; Zhang, Hui-Jun; Wang, Shaohua; Chen, Xiao-Feng

2017-11-15

LAG3 is a surface molecule found on a subset of immune cells. The precise function of LAG3 appears to be context-dependent. In this study, we investigated the effect of LAG3 on CD4 + CD25 - T cells from non-small cell lung cancer (NSCLC) patients. We found that in the peripheral blood mononuclear cells of NSCLC patients, LAG3 was significantly increased in CD4 + T cells directly ex vivo and primarily in the CD4 + CD25 - fraction, which was regulated by prolonged TCR stimulation and the presence of IL-27. TCR stimulation also increased CD25 expression, but not Foxp3 expression, in LAG3-expressing CD4 + CD25 - cells Compared to LAG3-nonexpressing CD4 + CD25 - cells, LAG3-expressing CD4 + CD25 - cells presented significantly higher levels of PD1 and TIM3, two inhibitory receptors best described in exhausted CD8 + T effector cells. LAG3-expressing CD4 + CD25 - cells also presented impaired proliferation compared with LAG3-nonexpressing CD4 + CD25 - cells but could be partially rescued by inhibiting both PD1 and TIM3. Interestingly, CD8 + T cells co-incubated with LAG3-expressing CD4 + CD25 - cells at equal cell numbers demonstrated significantly lower proliferation than CD8 + T cells incubated alone. Co-culture with CD8 + T cell and LAG3-expressing CD4 + CD25 - T cell also upregulated soluble IL-10 level in the supernatant, of which the concentration was positively correlated with the number of LAG3-expressing CD4 + CD25 - T cells. In addition, we found that LAG3-expressing CD4 + CD25 - T cells infiltrated the resected tumors and were present at higher frequencies of in metastases than in primary tumors. Taken together, these data suggest that LAG3-expressing CD4 + CD25 - T cells represent another regulatory immune cell type with potential to interfere with anti-tumor immunity. Copyright © 2017 Elsevier Inc. All rights reserved.

The cell cycle-regulated genes of Schizosaccharomyces pombe.

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Oliva, Anna; Rosebrock, Adam; Ferrezuelo, Francisco; Pyne, Saumyadipta; Chen, Haiying; Skiena, Steve; Futcher, Bruce; Leatherwood, Janet

2005-07-01

Many genes are regulated as an innate part of the eukaryotic cell cycle, and a complex transcriptional network helps enable the cyclic behavior of dividing cells. This transcriptional network has been studied in Saccharomyces cerevisiae (budding yeast) and elsewhere. To provide more perspective on these regulatory mechanisms, we have used microarrays to measure gene expression through the cell cycle of Schizosaccharomyces pombe (fission yeast). The 750 genes with the most significant oscillations were identified and analyzed. There were two broad waves of cell cycle transcription, one in early/mid G2 phase, and the other near the G2/M transition. The early/mid G2 wave included many genes involved in ribosome biogenesis, possibly explaining the cell cycle oscillation in protein synthesis in S. pombe. The G2/M wave included at least three distinctly regulated clusters of genes: one large cluster including mitosis, mitotic exit, and cell separation functions, one small cluster dedicated to DNA replication, and another small cluster dedicated to cytokinesis and division. S. pombe cell cycle genes have relatively long, complex promoters containing groups of multiple DNA sequence motifs, often of two, three, or more different kinds. Many of the genes, transcription factors, and regulatory mechanisms are conserved between S. pombe and S. cerevisiae. Finally, we found preliminary evidence for a nearly genome-wide oscillation in gene expression: 2,000 or more genes undergo slight oscillations in expression as a function of the cell cycle, although whether this is adaptive, or incidental to other events in the cell, such as chromatin condensation, we do not know.

The Cell Cycle–Regulated Genes of Schizosaccharomyces pombe

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Oliva, Anna; Rosebrock, Adam; Ferrezuelo, Francisco; Pyne, Saumyadipta; Chen, Haiying; Skiena, Steve

2005-01-01

Many genes are regulated as an innate part of the eukaryotic cell cycle, and a complex transcriptional network helps enable the cyclic behavior of dividing cells. This transcriptional network has been studied in Saccharomyces cerevisiae (budding yeast) and elsewhere. To provide more perspective on these regulatory mechanisms, we have used microarrays to measure gene expression through the cell cycle of Schizosaccharomyces pombe (fission yeast). The 750 genes with the most significant oscillations were identified and analyzed. There were two broad waves of cell cycle transcription, one in early/mid G2 phase, and the other near the G2/M transition. The early/mid G2 wave included many genes involved in ribosome biogenesis, possibly explaining the cell cycle oscillation in protein synthesis in S. pombe. The G2/M wave included at least three distinctly regulated clusters of genes: one large cluster including mitosis, mitotic exit, and cell separation functions, one small cluster dedicated to DNA replication, and another small cluster dedicated to cytokinesis and division. S. pombe cell cycle genes have relatively long, complex promoters containing groups of multiple DNA sequence motifs, often of two, three, or more different kinds. Many of the genes, transcription factors, and regulatory mechanisms are conserved between S. pombe and S. cerevisiae. Finally, we found preliminary evidence for a nearly genome-wide oscillation in gene expression: 2,000 or more genes undergo slight oscillations in expression as a function of the cell cycle, although whether this is adaptive, or incidental to other events in the cell, such as chromatin condensation, we do not know. PMID:15966770

Non-coding RNAs as epigenetic regulator of glioma stem-like cell differentiation

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Keisuke eKatsushima

2014-02-01

Full Text Available Glioblastomas show heterogeneous histological features. These distinct phenotypic states are thought to be associated with the presence of glioma stem cells (GSCs, which are highly tumorigenic and self-renewing sub-population of tumor cells that have different functional characteristics. Differentiation of GSCs may be regulated by multi-tiered epigenetic mechanisms that orchestrate the expression of thousands of genes. One such regulatory mechanism involves functional non-coding RNAs (ncRNAs, such as microRNAs (miRNAs; a large number of ncRNAs have been identified and shown to regulate the expression of genes associated with cell differentiation programs. Given the roles of miRNAs in cell differentiation, it is possible they are involved in the regulation of gene expression networks in GSCs that are important for the maintenance of the pluripotent state and for directing differentiation. Here, we review recent findings on ncRNAs associated with GSC differentiation and discuss how these ncRNAs contribute to the establishment of tissue heterogeneity during glioblastoma tumor formation.

SOX2 regulates acinar cell development in the salivary gland

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Emmerson, Elaine; May, Alison J; Nathan, Sara; Cruz-Pacheco, Noel; Lizama, Carlos O; Maliskova, Lenka; Zovein, Ann C; Shen, Yin; Muench, Marcus O; Knox, Sarah M

2017-01-01

Acinar cells play an essential role in the secretory function of exocrine organs. Despite this requirement, how acinar cells are generated during organogenesis is unclear. Using the acini-ductal network of the developing human and murine salivary gland, we demonstrate an unexpected role for SOX2 and parasympathetic nerves in generating the acinar lineage that has broad implications for epithelial morphogenesis. Despite SOX2 being expressed by progenitors that give rise to both acinar and duct cells, genetic ablation of SOX2 results in a failure to establish acini but not ducts. Furthermore, we show that SOX2 targets acinar-specific genes and is essential for the survival of acinar but not ductal cells. Finally, we illustrate an unexpected and novel role for peripheral nerves in the creation of acini throughout development via regulation of SOX2. Thus, SOX2 is a master regulator of the acinar cell lineage essential to the establishment of a functional organ. DOI: http://dx.doi.org/10.7554/eLife.26620.001 PMID:28623666

Cell-Cycle-Specific Function of p53 in Fanconi Anemia Hematopoietic Stem and Progenitor Cell Proliferation

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Xiaoli Li

2018-02-01

Full Text Available Summary: Overactive p53 has been proposed as an important pathophysiological factor for bone marrow failure syndromes, including Fanconi anemia (FA. Here, we report a p53-dependent effect on hematopoietic stem and progenitor cell (HSPC proliferation in mice deficient for the FA gene Fanca. Deletion of p53 in Fanca−/− mice leads to replicative exhaustion of the hematopoietic stem cell (HSC in transplant recipients. Using Fanca−/− HSCs expressing the separation-of-function mutant p53515C transgene, which selectively impairs the p53 function in apoptosis but keeps its cell-cycle checkpoint activities intact, we show that the p53 cell-cycle function is specifically required for the regulation of Fanca−/− HSC proliferation. Our results demonstrate that p53 plays a compensatory role in preventing FA HSCs from replicative exhaustion and suggest a cautious approach to manipulating p53 signaling as a therapeutic utility in FA. : In this article, Pang and colleagues demonstrate a p53-dependent HSPC proliferation regulation in mice deficient for the Fanca gene in the Fanconi anemia (FA pathway. They show that the p53 cell-cycle function is specifically required for the regulation of FA HSC proliferation. These results suggest that overactive p53 may represent a compensatory checkpoint mechanism for FA HSC proliferation. Keywords: p53, bone marrow failure, Fanconi anemia, hematopoietic stem and progenitor cells, apoptosis, cell cycle, proliferation

Cystatin F as a regulator of immune cell cytotoxicity.

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Kos, Janko; Nanut, Milica Perišić; Prunk, Mateja; Sabotič, Jerica; Dautović, Esmeralda; Jewett, Anahid

2018-05-10

Cysteine cathepsins are lysosomal peptidases involved in the regulation of innate and adaptive immune responses. Among the diverse processes, regulation of granule-dependent cytotoxicity of cytotoxic T-lymphocytes (CTLs) and natural killer (NK) cells during cancer progression has recently gained significant attention. The function of cysteine cathepsins is regulated by endogenous cysteine protease inhibitors-cystatins. Whereas other cystatins are generally cytosolic or extracellular proteins, cystatin F is present in endosomes and lysosomes and is thus able to regulate the activity of its target directly. It is delivered to endosomal/lysosomal vesicles as an inactive, disulphide-linked dimer. Proteolytic cleavage of its N-terminal part leads to the monomer, the only form that is a potent inhibitor of cathepsins C, H and L, involved in the activation of granzymes and perforin. In NK cells and CTLs the levels of active cathepsin C and of granzyme B are dependent on the concentration of monomeric, active cystatin F. In tumour microenvironment, inactive dimeric cystatin F can be secreted from tumour cells or immune cells and further taken up by the cytotoxic cells. Subsequent monomerization and inhibition of cysteine cathepsins within the endosomal/lysosomal vesicles impairs granzyme and perforin activation, and provokes cell anergy. Further, the glycosylation pattern has been shown to be important in controlling secretion of cystatin F from target cells, as well as internalization by cytotoxic cells and trafficking to endosomal/lysosomal vesicles. Cystatin F is therefore an important mediator used by bystander cells to reduce NK and T-cell cytotoxicity.

The Arabidopsis synaptotagmin SYTA regulates the cell-to-cell movement of diverse plant viruses

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Asako eUchiyama

2014-11-01

Full Text Available Synaptotagmins are a large gene family in animals that have been extensively characterized due to their role as calcium sensors to regulate synaptic vesicle exocytosis and endocytosis in neurons, and dense core vesicle exocytosis for hormone secretion from neuroendocrine cells. Thought to be exclusive to animals, synaptotagmins have recently been characterized in Arabidopsis thaliana, in which they comprise a five gene family. Using infectivity and leaf-based functional assays, we have shown that Arabidopsis SYTA regulates endocytosis and marks an endosomal vesicle recycling pathway to regulate movement protein-mediated trafficking of the Begomovirus Cabbage leaf curl virus (CaLCuV and the Tobamovirus Tobacco mosaic virus (TMV through plasmodesmata (Lewis and Lazarowitz, 2010. To determine whether SYTA has a central role in regulating the cell-to-cell trafficking of a wider range of diverse plant viruses, we extended our studies here to examine the role of SYTA in the cell-to-cell movement of additional plant viruses that employ different modes of movement, namely the Potyvirus Turnip mosaic virus (TuMV, the Caulimovirus Cauliflower mosaic virus (CaMV and the Tobamovirus Turnip vein clearing virus (TVCV, which in contrast to TMV does efficiently infect Arabidopsis. We found that both TuMV and TVCV systemic infection, and the cell-to-cell trafficking of the their movement proteins, were delayed in the Arabidopsis Col-0 syta-1 knockdown mutant. In contrast, CaMV systemic infection was not inhibited in syta-1. Our studies show that SYTA is a key regulator of plant virus intercellular movement, being necessary for the ability of diverse cell-to-cell movement proteins encoded by Begomoviruses (CaLCuV MP, Tobamoviruses (TVCV and TMV 30K protein and Potyviruses (TuMV P3N-PIPO to alter PD and thereby mediate virus cell-to-cell spread.

Dynamic autophagic activity affected the development of thoracic aortic dissection by regulating functional properties of smooth muscle cells

International Nuclear Information System (INIS)

Wang, Yang; Zhao, Zhi-Min; Zhang, Guan-Xin; Yang, Fan; Yan, Yan; Liu, Su-Xuan; Li, Song-Hua; Wang, Guo-Kun; Xu, Zhi-Yun

2016-01-01

The aortic medial degeneration is the key histopathologic feature of Thoracic aortic dissection (TAD). The aim of this study was to identify the change of autophagic activity in the aortic wall during TAD development, and to explore the roles of autophagy on regulating functional properties of smooth muscle cells (SMCs). Firstly, compared with control group (n = 11), the increased expression of autophagic markers Beclin1 and LC3 was detected in the aortic wall from TAD group (n = 23) by immunochemistry and western blot. We found that more autophagic vacuoles were present in the aortic wall of TAD patients using Transmission electron microscopy. Next, autophagic activity was examined in AD mice model established by β-aminopropionitrile fumarate (BAPN) and angiotensin II. Immunochemistry proved that autophagic activity was dynamically changed during AD development. Beclin1 and LC3 were detected up-regulated in the aortic wall in the second week after BAPN feeding, earlier than the fragmentation or loss of elastic fibers. When AD occurred in the 4th week, the expression of Beclin1 and LC3 began to decrease, but still higher than the control. Furthermore, autophagy was found to inhibit starvation-induced apoptosis of SMCs. Meanwhile, blockage of autophagy could suppress PDGF-induced phenotypic switch of SMCs. Taken together, autophagic activity was dynamically changed in the aortic wall during TAD development. The abnormal autophagy could regulate the functional properties of aortic SMCs, which might be the potential pathogenesis of TAD. - Highlights: • Autophagy is up-regulated in aorta wall from thoracic aorta dissection (TAD) patient. • Autophagic activity is dynamically changed during TAD development. • Dynamically change of autophagy is associated with pathological process of TAD. • Autophagy participate in the development of TAD by regulating function of SMCs.

Palmitoylation as a Functional Regulator of Neurotransmitter Receptors

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Vladimir S. Naumenko

2018-01-01

Full Text Available The majority of neuronal proteins involved in cellular signaling undergo different posttranslational modifications significantly affecting their functions. One of these modifications is a covalent attachment of a 16-C palmitic acid to one or more cysteine residues (S-palmitoylation within the target protein. Palmitoylation is a reversible modification, and repeated cycles of palmitoylation/depalmitoylation might be critically involved in the regulation of multiple signaling processes. Palmitoylation also represents a common posttranslational modification of the neurotransmitter receptors, including G protein-coupled receptors (GPCRs and ligand-gated ion channels (LICs. From the functional point of view, palmitoylation affects a wide span of neurotransmitter receptors activities including their trafficking, sorting, stability, residence lifetime at the cell surface, endocytosis, recycling, and synaptic clustering. This review summarizes the current knowledge on the palmitoylation of neurotransmitter receptors and its role in the regulation of receptors functions as well as in the control of different kinds of physiological and pathological behavior.

Regulation of TGFβ in the immune system: an emerging role for integrins and dendritic cells.

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Worthington, John J; Fenton, Thomas M; Czajkowska, Beata I; Klementowicz, Joanna E; Travis, Mark A

2012-12-01

Regulation of an immune response requires complex crosstalk between cells of the innate and adaptive immune systems, via both cell-cell contact and secretion of cytokines. An important cytokine with a broad regulatory role in the immune system is transforming growth factor-β (TGF-β). TGF-β is produced by and has effects on many different cells of the immune system, and plays fundamental roles in the regulation of immune responses during homeostasis, infection and disease. Although many cells can produce TGFβ, it is always produced as an inactive complex that must be activated to bind to the TGFβ receptor complex and promote downstream signalling. Thus, regulation of TGFβ activation is a crucial step in controlling TGFβ function. This review will discuss how TGFβ controls diverse immune responses and how TGFβ function is regulated, with a focus on recent work highlighting a critical role for the integrin αvβ8 expressed by dendritic cells in activating TGFβ. Copyright © 2012 Elsevier GmbH. All rights reserved.

Functional analysis of the cell cycle regulator Rca1 in Drosophila melanogaster

OpenAIRE

Zielke, Norman

2007-01-01

Tight regulation of APC/C activity is essential for cell cycle progression. An important class of negative APC/C regulators are the Rca1/Emi1 family proteins. All members of the Rca1/Emi1 family share a conserved zinc binding region (ZBR) which is essential for their inhibitory activity. The Rca1/Emi1 proteins belong to the class of F-box proteins that are known to act as substrate recognition subunits in SCF-E3-ligase complexes. Emi1 and Rca1 interact in vitro with members of the Skp family ...

NKp46 clusters at the immune synapse and regulates NK cell polarization

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Uzi eHadad

2015-09-01

Full Text Available Natural killer cells play an important role in first-line defense against tumor and virus-infected cells. The activity of NK cells is tightly regulated by a repertoire of cell-surface expressed inhibitory and activating receptors. NKp46 is a major NK cell activating receptor that is involved in the elimination of target cells. NK cells form different types of synapses that result in distinct functional outcomes: cytotoxic, inhibitory, and regulatory. Recent studies revealed that complex integration of NK receptor signaling controls cytoskeletal rearrangement and other immune synapse-related events. However the distinct nature by which NKp46 participates in NK immunological synapse formation and function remains unknown. In this study we determined that NKp46 forms microclusters structures at the immune synapse between NK cells and target cells. Over-expression of human NKp46 is correlated with increased accumulation of F-actin mesh at the immune synapse. Concordantly, knock-down of NKp46 in primary human NK cells decreased recruitment of F-actin to the synapse. Live cell imaging experiments showed a linear correlation between NKp46 expression and lytic granules polarization to the immune synapse. Taken together, our data suggest that NKp46 signaling directly regulates the NK lytic immune synapse from early formation to late function.

Analysis of cell-cycle regulation following exposure of lung-derived cells to γ-rays

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Trani, D.; Lucchetti, C.; Cassone, M.; D'Agostino, L.; Caputi, M.; Giordano, A.

Acute exposure of mammalian cells to ionizing radiation results in a delay of cell-cycle progression and/or augmentation of apoptosis. Following ionizing radiation-induced DNA damage, cell-cycle arrest in the G1- or G2-phase of the cell-cycle prevents or delays DNA replication or mitosis, providing time for the DNA repair machinery to exert its function. Deregulation or failing of cell-cycle checkpoints and/or DNA repair mechanisms may lead normal cells bearing chromosome mutations to acquire neoplastic autonomy, which in turn can trigger the onset of cancer. Existing studies have focused on the impact of p53 status on the radiation response of lung cancer (LC) cell lines in terms of both cell-cycle regulation and apoptosis, while no comparative studies have been performed on the radiation response of lung derived normal and cancerous epithelial cells. To investigate the radiation response in normal and cancerous phenotypes, along with the role and impact of p53 status, and possible correlations with pRb/p105 or other proteins involved in carcinogenesis and cell-cycle regulation, we selected two lung-derived epithelial cell lines, one normal (NL20, p53 wild-type) and one non-small cell lung cancer (NSCLC), H358 (known to be p53-deficient). We compared the levels of γ-induced cell proliferation ability, cell-cycle arrest, apoptotic index, and expression levels of cell-cycle regulating and regulated proteins. The different cell sensitivity, apoptotic response and protein expression profiles resulting from our study for NL20 and H358 cells suggest that still unknown mechanisms involving p53, pRb/p105 and their target molecules might play a pivotal role in determining cell sensitivity and resistance upon exposure to ionizing radiation.

Post-transcriptional gene expression control by NANOS is up-regulated and functionally important in pRb-deficient cells.

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Miles, Wayne O; Korenjak, Michael; Griffiths, Lyra M; Dyer, Michael A; Provero, Paolo; Dyson, Nicholas J

2014-10-01

Inactivation of the retinoblastoma tumor suppressor (pRb) is a common oncogenic event that alters the expression of genes important for cell cycle progression, senescence, and apoptosis. However, in many contexts, the properties of pRb-deficient cells are similar to wild-type cells suggesting there may be processes that counterbalance the transcriptional changes associated with pRb inactivation. Therefore, we have looked for sets of evolutionary conserved, functionally related genes that are direct targets of pRb/E2F proteins. We show that the expression of NANOS, a key facilitator of the Pumilio (PUM) post-transcriptional repressor complex, is directly repressed by pRb/E2F in flies and humans. In both species, NANOS expression increases following inactivation of pRb/RBF1 and becomes important for tissue homeostasis. By analyzing datasets from normal retinal tissue and pRb-null retinoblastomas, we find a strong enrichment for putative PUM substrates among genes de-regulated in tumors. These include pro-apoptotic genes that are transcriptionally down-regulated upon pRb loss, and we characterize two such candidates, MAP2K3 and MAP3K1, as direct PUM substrates. Our data suggest that NANOS increases in importance in pRb-deficient cells and helps to maintain homeostasis by repressing the translation of transcripts containing PUM Regulatory Elements (PRE). © 2014 The Authors.

Regulation of development and function of different T cell subtypes by Rel/NF-κB family members

International Nuclear Information System (INIS)

Vallabhapurapu, S.

2004-09-01

This study reveals the requirement of distinct members of the Rel/NF-κB family in both hematopoietic and non-hematopoietic cells for the development of thymic NKT cells. Activation of NF-κB via the classical IκBα-regulated pathway is required within the NKT precursors for their efficient maturation from NK1.1 - precursors to mature NK1.1 + NKT cells. The Rel/NF-κB family member RelB, on the other hand, is required in thymic stromal cells for the generation of very early NK1.1 - precursors. NF-κB-inducing kinase (NIK) has also been shown to be required in thymic stromal cells for NKT cell development and this study demonstrates that NIK specifically regulates both constitutive and signal-induced DNA binding of RelB, but not RelA. Moreover, NIK-induced DNA binding of RelB depends on the processing of inhibitory p100 to p52, revealing an alternate pathway of NF-κB induction. Thus, Rel/NF-κB complexes activated by the classical IκBα-regulated pathway in NKT precursors and an alternate NIK/p100/RelB pathway in thymic stromal cells regulate different stages of NKT cell development. (orig.)

Regulation of development and function of different T cell subtypes by Rel/NF-{kappa}B family members

Energy Technology Data Exchange (ETDEWEB)

Vallabhapurapu, S.

2004-09-01

This study reveals the requirement of distinct members of the Rel/NF-{kappa}B family in both hematopoietic and non-hematopoietic cells for the development of thymic NKT cells. Activation of NF-{kappa}B via the classical I{kappa}B{alpha}-regulated pathway is required within the NKT precursors for their efficient maturation from NK1.1{sup -} precursors to mature NK1.1{sup +} NKT cells. The Rel/NF-{kappa}B family member RelB, on the other hand, is required in thymic stromal cells for the generation of very early NK1.1{sup -} precursors. NF-{kappa}B-inducing kinase (NIK) has also been shown to be required in thymic stromal cells for NKT cell development and this study demonstrates that NIK specifically regulates both constitutive and signal-induced DNA binding of RelB, but not RelA. Moreover, NIK-induced DNA binding of RelB depends on the processing of inhibitory p100 to p52, revealing an alternate pathway of NF-{kappa}B induction. Thus, Rel/NF-{kappa}B complexes activated by the classical I{kappa}B{alpha}-regulated pathway in NKT precursors and an alternate NIK/p100/RelB pathway in thymic stromal cells regulate different stages of NKT cell development. (orig.)

The vitamin D receptor and T cell function

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Martin eKongsbak

2013-06-01

Full Text Available The vitamin D receptor (VDR is a nuclear, ligand-dependent transcription factor that in complex with hormonally active vitamin D, 1,25(OH2D3, regulates the expression of more than 900 genes involved in a wide array of physiological functions. The impact of 1,25(OH2D3-VDR signaling on immune function has been the focus of many recent studies as a link between 1,25(OH2D3 and sus-ceptibility to various infections and to development of a variety of inflammatory diseases has been suggested. It is also becoming increasingly clear that microbes slow down immune reactivity by dysregulating the VDR ultimately to increase their chance of survival. Immune modulatory therapies that enhance VDR expression and activity are therefore considered in the clinic today to a greater extent. As T cells are of great importance for both protective immunity and development of inflammatory diseases a variety of studies have been engaged investigating the impact of VDR ex-pression in T cells and found that VDR expression and activity plays an important role in both T cell development, differentiation and effector function. In this review we will analyze current know-ledge of VDR regulation and function in T cells and discuss its importance for immune activity.

Structural interaction and functional regulation of polycystin-2 by filamin.

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Qian Wang

Full Text Available Filamins are important actin cross-linking proteins implicated in scaffolding, membrane stabilization and signal transduction, through interaction with ion channels, receptors and signaling proteins. Here we report the physical and functional interaction between filamins and polycystin-2, a TRP-type cation channel mutated in 10-15% patients with autosomal dominant polycystic kidney disease. Yeast two-hybrid and GST pull-down experiments demonstrated that the C-termini of filamin isoforms A, B and C directly bind to both the intracellular N- and C-termini of polycystin-2. Reciprocal co-immunoprecipitation experiments showed that endogenous polycystin-2 and filamins are in the same complexes in renal epithelial cells and human melanoma A7 cells. We then examined the effect of filamin on polycystin-2 channel function by electrophysiology studies with a lipid bilayer reconstitution system and found that filamin-A substantially inhibits polycystin-2 channel activity. Our study indicates that filamins are important regulators of polycystin-2 channel function, and further links actin cytoskeletal dynamics to the regulation of this channel protein.

Epigenetic regulation of hematopoietic stem cell aging

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Beerman, Isabel; Rossi, Derrick J.

2014-01-01

Aging is invariably associated with alterations of the hematopoietic stem cell (HSC) compartment, including loss of functional capacity, altered clonal composition, and changes in lineage contribution. Although accumulation of DNA damage occurs during HSC aging, it is unlikely such consistent aging phenotypes could be solely attributed to changes in DNA integrity. Another mechanism by which heritable traits could contribute to the changes in the functional potential of aged HSCs is through alterations in the epigenetic landscape of adult stem cells. Indeed, recent studies on hematopoietic stem cells have suggested that altered epigenetic profiles are associated with HSC aging and play a key role in modulating the functional potential of HSCs at different stages during ontogeny. Even small changes of the epigenetic landscape can lead to robustly altered expression patterns, either directly by loss of regulatory control or through indirect, additive effects, ultimately leading to transcriptional changes of the stem cells. Potential drivers of such changes in the epigenetic landscape of aged HSCs include proliferative history, DNA damage, and deregulation of key epigenetic enzymes and complexes. This review will focus largely on the two most characterized epigenetic marks – DNA methylation and histone modifications – but will also discuss the potential role of non-coding RNAs in regulating HSC function during aging

Epigenetic regulation of hematopoietic stem cell aging

Energy Technology Data Exchange (ETDEWEB)

Beerman, Isabel, E-mail: isabel.beerman@childrens.harvard.edu [Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138 (United States); Department of Pediatrics, Harvard Medical School, Boston, MA 02115 (United States); Program in Cellular and Molecular Medicine, Division of Hematology/Oncology, Boston Children' s Hospital, MA 02116 (United States); Rossi, Derrick J. [Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138 (United States); Department of Pediatrics, Harvard Medical School, Boston, MA 02115 (United States); Program in Cellular and Molecular Medicine, Division of Hematology/Oncology, Boston Children' s Hospital, MA 02116 (United States)

2014-12-10

Aging is invariably associated with alterations of the hematopoietic stem cell (HSC) compartment, including loss of functional capacity, altered clonal composition, and changes in lineage contribution. Although accumulation of DNA damage occurs during HSC aging, it is unlikely such consistent aging phenotypes could be solely attributed to changes in DNA integrity. Another mechanism by which heritable traits could contribute to the changes in the functional potential of aged HSCs is through alterations in the epigenetic landscape of adult stem cells. Indeed, recent studies on hematopoietic stem cells have suggested that altered epigenetic profiles are associated with HSC aging and play a key role in modulating the functional potential of HSCs at different stages during ontogeny. Even small changes of the epigenetic landscape can lead to robustly altered expression patterns, either directly by loss of regulatory control or through indirect, additive effects, ultimately leading to transcriptional changes of the stem cells. Potential drivers of such changes in the epigenetic landscape of aged HSCs include proliferative history, DNA damage, and deregulation of key epigenetic enzymes and complexes. This review will focus largely on the two most characterized epigenetic marks – DNA methylation and histone modifications – but will also discuss the potential role of non-coding RNAs in regulating HSC function during aging.

Bex2 regulates cell proliferation and apoptosis in malignant glioma cells via the c-Jun NH2-terminal kinase pathway

International Nuclear Information System (INIS)

Zhou, Xiuping; Meng, Qingming; Xu, Xuebin; Zhi, Tongle; Shi, Qiong; Wang, Yong; Yu, Rutong

2012-01-01

Highlights: ► The expression levels of Bex2 markedly increased in glioma tissues. ► Bex2 over-expression promoted cell proliferation, while its down-regulation inhibited cell growth. ► Bex2 down-regulation promoted cell apoptosis via JNK/c-Jun signaling pathway. -- Abstract: The function of Bex2, a member of the Brain Expressed X-linked gene family, in glioma is controversial and its mechanism is largely unknown. We report here that Bex2 regulates cell proliferation and apoptosis in malignant glioma cells via the c-Jun NH2-terminal kinase (JNK) pathway. The expression level of Bex2 is markedly increased in glioma tissues. We observed that Bex2 over-expression promotes cell proliferation, while down-regulation of Bex2 inhibits cell growth. Furthermore, Bex2 down-regulation promotes cell apoptosis and activates the JNK pathway; these effects were abolished by administration of the JNK specific inhibitor, (SP600125). Thus, Bex2 may be an important player during the development of glioma.

Proline-rich tyrosine kinase 2 (Pyk2) mediates vascular endothelial-cadherin-based cell-cell adhesion by regulating beta-catenin tyrosine phosphorylation

NARCIS (Netherlands)

van Buul, Jaap D.; Anthony, Eloise C.; Fernandez-Borja, Mar; Burridge, Keith; Hordijk, Peter L.

2005-01-01

Vascular endothelial-cadherin (VE-cadherin) controls endothelial cell-cell adhesion and preserves endothelial integrity. In order to maintain endothelial barrier function, VE-cadherin function is tightly regulated through mechanisms that involve protein phosphorylation and cytoskeletal dynamics.

Modeling the cost and benefit of proteome regulation in a growing bacterial cell

Science.gov (United States)

Sharma, Pooja; Pratim Pandey, Parth; Jain, Sanjay

2018-07-01

Escherichia coli cells differentially regulate the production of metabolic and ribosomal proteins in order to stay close to an optimal growth rate in different environments, and exhibit the bacterial growth laws as a consequence. We present a simple mathematical model of a growing-dividing cell in which an internal dynamical mechanism regulates the allocation of proteomic resources between different protein sectors. The model allows an endogenous determination of the growth rate of the cell as a function of cellular and environmental parameters, and reproduces the bacterial growth laws. We use the model and its variants to study the balance between the cost and benefit of regulation. A cost is incurred because cellular resources are diverted to produce the regulatory apparatus. We show that there is a window of environments or a ‘niche’ in which the unregulated cell has a higher fitness than the regulated cell. Outside this niche there is a large space of constant and time varying environments in which regulation is an advantage. A knowledge of the ‘niche boundaries’ allows one to gain an intuitive understanding of the class of environments in which regulation is an advantage for the organism and which would therefore favour the evolution of regulation. The model allows us to determine the ‘niche boundaries’ as a function of cellular parameters such as the size of the burden of the regulatory apparatus. This class of models may be useful in elucidating various tradeoffs in cells and in making in-silico predictions relevant for synthetic biology.

The bHLH factors Dpn and members of the E(spl complex mediate the function of Notch signalling regulating cell proliferation during wing disc development

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Beatriz P. San Juan

2012-05-01

The Notch signalling pathway plays an essential role in the intricate control of cell proliferation and pattern formation in many organs during animal development. In addition, mutations in most members of this pathway are well characterized and frequently lead to tumour formation. The Drosophila imaginal wing discs have provided a suitable model system for the genetic and molecular analysis of the different pathway functions. During disc development, Notch signalling at the presumptive wing margin is necessary for the restricted activation of genes required for pattern formation control and disc proliferation. Interestingly, in different cellular contexts within the wing disc, Notch can either promote cell proliferation or can block the G1-S transition by negatively regulating the expression of dmyc and bantam micro RNA. The target genes of Notch signalling that are required for these functions have not been identified. Here, we show that the Hes vertebrate homolog, deadpan (dpn, and the Enhancer-of-split complex (E(splC genes act redundantly and cooperatively to mediate the Notch signalling function regulating cell proliferation during wing disc development.

Thymic function in the regulation of T cells, and molecular mechanisms underlying the modulation of cytokines and stress signaling (Review).

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Yan, Fenggen; Mo, Xiumei; Liu, Junfeng; Ye, Siqi; Zeng, Xing; Chen, Dacan

2017-11-01

The thymus is critical in establishing and maintaining the appropriate microenvironment for promoting the development and selection of T cells. The function and structure of the thymus gland has been extensively studied, particularly as the thymus serves an important physiological role in the lymphatic system. Numerous studies have investigated the morphological features of thymic involution. Recently, research attention has increasingly been focused on thymic proteins as targets for drug intervention. Omics approaches have yielded novel insights into the thymus and possible drug targets. The present review addresses the signaling and transcriptional functions of the thymus, including the molecular mechanisms underlying the regulatory functions of T cells and their role in the immune system. In addition, the levels of cytokines secreted in the thymus have a significant effect on thymic functions, including thymocyte migration and development, thymic atrophy and thymic recovery. Furthermore, the regulation and molecular mechanisms of stress‑mediated thymic atrophy and involution were investigated, with particular emphasis on thymic function as a potential target for drug development and discovery using proteomics.

NFIX Regulates Neural Progenitor Cell Differentiation During Hippocampal Morphogenesis

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Heng, Yee Hsieh Evelyn; McLeay, Robert C.; Harvey, Tracey J.; Smith, Aaron G.; Barry, Guy; Cato, Kathleen; Plachez, Céline; Little, Erica; Mason, Sharon; Dixon, Chantelle; Gronostajski, Richard M.; Bailey, Timothy L.; Richards, Linda J.; Piper, Michael

2014-01-01

Neural progenitor cells have the ability to give rise to neurons and glia in the embryonic, postnatal and adult brain. During development, the program regulating whether these cells divide and self-renew or exit the cell cycle and differentiate is tightly controlled, and imbalances to the normal trajectory of this process can lead to severe functional consequences. However, our understanding of the molecular regulation of these fundamental events remains limited. Moreover, processes underpinning development of the postnatal neurogenic niches within the cortex remain poorly defined. Here, we demonstrate that Nuclear factor one X (NFIX) is expressed by neural progenitor cells within the embryonic hippocampus, and that progenitor cell differentiation is delayed within Nfix−/− mice. Moreover, we reveal that the morphology of the dentate gyrus in postnatal Nfix−/− mice is abnormal, with fewer subgranular zone neural progenitor cells being generated in the absence of this transcription factor. Mechanistically, we demonstrate that the progenitor cell maintenance factor Sry-related HMG box 9 (SOX9) is upregulated in the hippocampus of Nfix−/− mice and demonstrate that NFIX can repress Sox9 promoter-driven transcription. Collectively, our findings demonstrate that NFIX plays a central role in hippocampal morphogenesis, regulating the formation of neuronal and glial populations within this structure. PMID:23042739

Pten Regulates Retinal Amacrine Cell Number by Modulating Akt, Tgfβ, and Erk Signaling.

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Tachibana, Nobuhiko; Cantrup, Robert; Dixit, Rajiv; Touahri, Yacine; Kaushik, Gaurav; Zinyk, Dawn; Daftarian, Narsis; Biernaskie, Jeff; McFarlane, Sarah; Schuurmans, Carol

2016-09-07

All tissues are genetically programmed to acquire an optimal size that is defined by total cell number and individual cellular dimensions. The retina contains stereotyped proportions of one glial and six neuronal cell types that are generated in overlapping waves. How multipotent retinal progenitors know when to switch from making one cell type to the next so that appropriate numbers of each cell type are generated is poorly understood. Pten is a phosphatase that controls progenitor cell proliferation and differentiation in several lineages. Here, using a conditional loss-of-function strategy, we found that Pten regulates retinal cell division and is required to produce the full complement of rod photoreceptors and amacrine cells in mouse. We focused on amacrine cell number control, identifying three downstream Pten effector pathways. First, phosphoinositide 3-kinase/Akt signaling is hyperactivated in Pten conditional knock-out (cKO) retinas, and misexpression of constitutively active Akt (Akt-CA) in retinal explants phenocopies the reduction in amacrine cell production observed in Pten cKOs. Second, Akt-CA activates Tgfβ signaling in retinal explants, which is a negative feedback pathway for amacrine cell production. Accordingly, Tgfβ signaling is elevated in Pten cKO retinas, and epistatic analyses placed Pten downstream of TgfβRII in amacrine cell number control. Finally, Pten regulates Raf/Mek/Erk signaling levels to promote the differentiation of all amacrine cell subtypes, which are each reduced in number in Pten cKOs. Pten is thus a positive regulator of amacrine cell production, acting via multiple downstream pathways, highlighting its diverse actions as a mediator of cell number control. Despite the importance of size for optimal organ function, how individual cell types are generated in correct proportions is poorly understood. There are several ways to control cell number, including readouts of organ function (e.g., secreted hormones reach functional

Biophysical force regulation in 3D tumor cell invasion

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Wu, Mingming

When embedded within 3D extracellular matrices (ECM), animal cells constantly probe and adapt to the ECM locally (at cell length scale) and exert forces and communicate with other cells globally (up to 10 times of cell length). It is now well accepted that mechanical crosstalk between animal cells and their microenvironment critically regulate cell function such as migration, proliferation and differentiation. Disruption of the cell-ECM crosstalk is implicated in a number of pathologic processes including tumor progression and fibrosis. Central to the problem of cell-ECM crosstalk is the physical force that cells generate. By measuring single cell generated force within 3D collagen matrices, we revealed a mechanical crosstalk mechanism between the tumor cells and the ECM. Cells generate sufficient force to stiffen collagen fiber network, and stiffer matrix, in return promotes larger cell force generation. Our work highlights the importance of fibrous nonlinear elasticity in regulating tumor cell-ECM interaction, and results may have implications in the rapid tissue stiffening commonly found in tumor progression and fibrosis. This work is partially supported by NIH Grants R21RR025801 and R21GM103388.

An Integrated Cell Purification and Genomics Strategy Reveals Multiple Regulators of Pancreas Development

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Benitez, Cecil M.; Qu, Kun; Sugiyama, Takuya; Pauerstein, Philip T.; Liu, Yinghua; Tsai, Jennifer; Gu, Xueying; Ghodasara, Amar; Arda, H. Efsun; Zhang, Jiajing; Dekker, Joseph D.; Tucker, Haley O.; Chang, Howard Y.; Kim, Seung K.

2014-01-01

The regulatory logic underlying global transcriptional programs controlling development of visceral organs like the pancreas remains undiscovered. Here, we profiled gene expression in 12 purified populations of fetal and adult pancreatic epithelial cells representing crucial progenitor cell subsets, and their endocrine or exocrine progeny. Using probabilistic models to decode the general programs organizing gene expression, we identified co-expressed gene sets in cell subsets that revealed patterns and processes governing progenitor cell development, lineage specification, and endocrine cell maturation. Purification of Neurog3 mutant cells and module network analysis linked established regulators such as Neurog3 to unrecognized gene targets and roles in pancreas development. Iterative module network analysis nominated and prioritized transcriptional regulators, including diabetes risk genes. Functional validation of a subset of candidate regulators with corresponding mutant mice revealed that the transcription factors Etv1, Prdm16, Runx1t1 and Bcl11a are essential for pancreas development. Our integrated approach provides a unique framework for identifying regulatory genes and functional gene sets underlying pancreas development and associated diseases such as diabetes mellitus. PMID:25330008

An integrated cell purification and genomics strategy reveals multiple regulators of pancreas development.

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Cecil M Benitez

2014-10-01

Full Text Available The regulatory logic underlying global transcriptional programs controlling development of visceral organs like the pancreas remains undiscovered. Here, we profiled gene expression in 12 purified populations of fetal and adult pancreatic epithelial cells representing crucial progenitor cell subsets, and their endocrine or exocrine progeny. Using probabilistic models to decode the general programs organizing gene expression, we identified co-expressed gene sets in cell subsets that revealed patterns and processes governing progenitor cell development, lineage specification, and endocrine cell maturation. Purification of Neurog3 mutant cells and module network analysis linked established regulators such as Neurog3 to unrecognized gene targets and roles in pancreas development. Iterative module network analysis nominated and prioritized transcriptional regulators, including diabetes risk genes. Functional validation of a subset of candidate regulators with corresponding mutant mice revealed that the transcription factors Etv1, Prdm16, Runx1t1 and Bcl11a are essential for pancreas development. Our integrated approach provides a unique framework for identifying regulatory genes and functional gene sets underlying pancreas development and associated diseases such as diabetes mellitus.

Demethoxycurcumin inhibited human epithelia ovarian cancer cells' growth via up-regulating miR-551a.

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Du, Zhenhua; Sha, Xianqun

2017-03-01

Curcumin is a natural agent that has ability to dampen tumor cells' growth. However, the natural form of curcumin is prone to degrade and unstable in vitro. Here, we demonstrated that demethoxycurcumin (a curcumin-related demethoxy compound) could inhibit cell proliferation and induce apoptosis of ovarian cancer cells. Moreover, IRS2/PI3K/Akt axis was inactivated in cells treated with demethoxycurcumin. Quantitative real-time reverse transcription polymerase chain reaction demonstrated that miR-551a was down-regulated in ovarian cancer tissues and ovarian cancer cell lines. Over-expression of miR-551a inhibited cell proliferation and induced apoptosis of ovarian cancer cells, whereas down-regulation of miR-551a exerted the opposite function. Luciferase assays confirmed that there was a binding site of miR-551a in IRS2, and we found that miR-551a exerted tumor-suppressive function by targeting IRS2 in ovarian cancer cells. Remarkably, miR-551a was up-regulated in the cells treated with demethoxycurcumin, and demethoxycurcumin suppressed IRS2 by restoration of miR-551a. In conclusion, demethoxycurcumin hindered ovarian cancer cells' malignant progress via up-regulating miR-551a.

The cell cycle-regulated genes of Schizosaccharomyces pombe.

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Anna Oliva

2005-07-01

Full Text Available Many genes are regulated as an innate part of the eukaryotic cell cycle, and a complex transcriptional network helps enable the cyclic behavior of dividing cells. This transcriptional network has been studied in Saccharomyces cerevisiae (budding yeast and elsewhere. To provide more perspective on these regulatory mechanisms, we have used microarrays to measure gene expression through the cell cycle of Schizosaccharomyces pombe (fission yeast. The 750 genes with the most significant oscillations were identified and analyzed. There were two broad waves of cell cycle transcription, one in early/mid G2 phase, and the other near the G2/M transition. The early/mid G2 wave included many genes involved in ribosome biogenesis, possibly explaining the cell cycle oscillation in protein synthesis in S. pombe. The G2/M wave included at least three distinctly regulated clusters of genes: one large cluster including mitosis, mitotic exit, and cell separation functions, one small cluster dedicated to DNA replication, and another small cluster dedicated to cytokinesis and division. S. pombe cell cycle genes have relatively long, complex promoters containing groups of multiple DNA sequence motifs, often of two, three, or more different kinds. Many of the genes, transcription factors, and regulatory mechanisms are conserved between S. pombe and S. cerevisiae. Finally, we found preliminary evidence for a nearly genome-wide oscillation in gene expression: 2,000 or more genes undergo slight oscillations in expression as a function of the cell cycle, although whether this is adaptive, or incidental to other events in the cell, such as chromatin condensation, we do not know.

HDAC up-regulation in early colon field carcinogenesis is involved in cell tumorigenicity through regulation of chromatin structure.

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Yolanda Stypula-Cyrus

Full Text Available Normal cell function is dependent on the proper maintenance of chromatin structure. Regulation of chromatin structure is controlled by histone modifications that directly influence chromatin architecture and genome function. Specifically, the histone deacetylase (HDAC family of proteins modulate chromatin compaction and are commonly dysregulated in many tumors, including colorectal cancer (CRC. However, the role of HDAC proteins in early colorectal carcinogenesis has not been previously reported. We found HDAC1, HDAC2, HDAC3, HDAC5, and HDAC7 all to be up-regulated in the field of human CRC. Furthermore, we observed that HDAC2 up-regulation is one of the earliest events in CRC carcinogenesis and observed this in human field carcinogenesis, the azoxymethane-treated rat model, and in more aggressive colon cancer cell lines. The universality of HDAC2 up-regulation suggests that HDAC2 up-regulation is a novel and important early event in CRC, which may serve as a biomarker. HDAC inhibitors (HDACIs interfere with tumorigenic HDAC activity; however, the precise mechanisms involved in this process remain to be elucidated. We confirmed that HDAC inhibition by valproic acid (VPA targeted the more aggressive cell line. Using nuclease digestion assays and transmission electron microscopy imaging, we observed that VPA treatment induced greater changes in chromatin structure in the more aggressive cell line. Furthermore, we used the novel imaging technique partial wave spectroscopy (PWS to quantify nanoscale alterations in chromatin. We noted that the PWS results are consistent with the biological assays, indicating a greater effect of VPA treatment in the more aggressive cell type. Together, these results demonstrate the importance of HDAC activity in early carcinogenic events and the unique role of higher-order chromatin structure in determining cell tumorigenicity.

Foxa2 and Pdx1 cooperatively regulate postnatal maturation of pancreatic β-cells

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Aimée Bastidas-Ponce

2017-06-01

Full Text Available Objective: The transcription factors (TF Foxa2 and Pdx1 are key regulators of beta-cell (β-cell development and function. Mutations of these TFs or their respective cis-regulatory consensus binding sites have been linked to maturity diabetes of the young (MODY, pancreas agenesis, or diabetes susceptibility in human. Although Foxa2 has been shown to directly regulate Pdx1 expression during mouse embryonic development, the impact of this gene regulatory interaction on postnatal β-cell maturation remains obscure. Methods: In order to easily monitor the expression domains of Foxa2 and Pdx1 and analyze their functional interconnection, we generated a novel double knock-in homozygous (FVFPBFDHom fluorescent reporter mouse model by crossing the previously described Foxa2-Venus fusion (FVF with the newly generated Pdx1-BFP (blue fluorescent protein fusion (PBF mice. Results: Although adult PBF homozygous animals exhibited a reduction in expression levels of Pdx1, they are normoglycemic. On the contrary, despite normal pancreas and endocrine development, the FVFPBFDHom reporter male animals developed hyperglycemia at weaning age and displayed a reduction in Pdx1 levels in islets, which coincided with alterations in β-cell number and islet architecture. The failure to establish mature β-cells resulted in loss of β-cell identity and trans-differentiation towards other endocrine cell fates. Further analysis suggested that Foxa2 and Pdx1 genetically and functionally cooperate to regulate maturation of adult β-cells. Conclusions: Our data show that the maturation of pancreatic β-cells requires the cooperative function of Foxa2 and Pdx1. Understanding the postnatal gene regulatory network of β-cell maturation will help to decipher pathomechanisms of diabetes and identify triggers to regenerate dedifferentiated β-cell mass. Keywords: Foxa2, Pdx1, β-Cell maturation, β-Cell identity, Trans-differentiation

TET2 Regulates Mast Cell Differentiation and Proliferation through Catalytic and Non-catalytic Activities

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Sara Montagner

2016-05-01

Full Text Available Summary: Dioxygenases of the TET family impact genome functions by converting 5-methylcytosine (5mC in DNA to 5-hydroxymethylcytosine (5hmC. Here, we identified TET2 as a crucial regulator of mast cell differentiation and proliferation. In the absence of TET2, mast cells showed disrupted gene expression and altered genome-wide 5hmC deposition, especially at enhancers and in the proximity of downregulated genes. Impaired differentiation of Tet2-ablated cells could be relieved or further exacerbated by modulating the activity of other TET family members, and mechanistically it could be linked to the dysregulated expression of C/EBP family transcription factors. Conversely, the marked increase in proliferation induced by the loss of TET2 could be rescued exclusively by re-expression of wild-type or catalytically inactive TET2. Our data indicate that, in the absence of TET2, mast cell differentiation is under the control of compensatory mechanisms mediated by other TET family members, while proliferation is strictly dependent on TET2 expression. : The impact of TET enzymes on gene expression and cell function is incompletely understood. Montagner et al. investigate the TET-mediated regulation of mast cell differentiation and function, uncover transcriptional pathways regulated by TET2, and identify both enzymatic activity-dependent and -independent functions of TET2. Keywords: differentiation, DNA hydroxymethylation, epigenetics, mast cells, proliferation, TET

Human CD5+ Innate Lymphoid Cells Are Functionally Immature and Their Development from CD34+ Progenitor Cells Is Regulated by Id2

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Maho Nagasawa

2017-08-01

Full Text Available Innate lymphoid cells (ILCs have emerged as a key cell type involved in surveillance and maintenance of mucosal tissues. Mouse ILCs rely on the transcriptional regulator Inhibitor of DNA-binding protein 2 (Id2 for their development. Here, we show that Id2 also drives development of human ILC because forced expression of Id2 in human thymic progenitors blocked T cell commitment, upregulated CD161 and promyelocytic leukemia zinc finger (PLZF, and maintained CD127 expression, markers that are characteristic for human ILCs. Surprisingly CD5 was also expressed on these in vitro generated ILCs. This was not an in vitro artifact because CD5 was also found on ex vivo isolated ILCs from thymus and from umbilical cord blood. CD5 was also expressed on small proportions of ILC2 and ILC3. CD5+ ILCs were functionally immature, but could further differentiate into mature CD5− cytokine-secreting ILCs. Our data show that Id2 governs human ILC development from thymic progenitor cells toward immature CD5+ ILCs.

Deep-Sea-Derived Butyrolactone I Suppresses Ovalbumin-Induced Anaphylaxis by Regulating Mast Cell Function in a Murine Model.

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Liu, Qing-Mei; Xie, Chun-Lan; Gao, Yuan-Yuan; Liu, Bo; Lin, Wei-Xiang; Liu, Hong; Cao, Min-Jie; Su, Wen-Jin; Yang, Xian-Wen; Liu, Guang-Ming

2018-05-22

Deep-sea-derived butyrolactone I (BTL-I), which was identified as a type of butanolide, was isolated from Aspergillus sp. Ovalbumin (OVA)-induced BALB/c anaphylaxis was established to explore the antifood allergic activity of BTL-I. As a result, BTL-I was able to alleviate OVA-induced allergy symptoms, reduce the levels of histamine and mouse mast cell proteinases, inhibit OVA-specific IgE, and decrease the population of mast cells in the spleen and mesenteric lymph nodes. BTL-I also significantly suppressed mast-dependent passive cutaneous anaphylaxis. Additionally, the maturation of bone marrow-derived mast cells (BMMCs) declined as BTL-I caused down-regulation of c-KIT receptors. Furthermore, molecular docking analyses revealed that BTL-I interacted with the inhibitory receptor, FcγRIIB. In conclusion, the reduction of mast cell function by deep-sea-derived BTL-I as well as its interactions with the inhibitory receptor, FcγRIIB, may contribute to BTL-I-related protection against food anaphylaxis.

In vivo labelling of functional ribosomes reveals spatial regulation during starvation in Podospora anserina

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Silar Philippe

2000-11-01

Full Text Available Abstract Background To date, in eukaryotes, ribosomal protein expression is known to be regulated at the transcriptional and/or translational levels. But other forms of regulation may be possible. Results Here, we report the successful tagging of functional ribosomal particles with a S7-GFP chimaeric protein, making it possible to observe in vivo ribosome dynamics in the filamentous fungus Podospora anserina. Microscopic observations revealed a novel kind of ribosomal protein regulation during the passage between cell growth and stationary phases, with a transient accumulation of ribosomal proteins and/or ribosome subunits in the nucleus, possibly the nucleolus, being observed at the beginning of stationary phase. Conclusion Nuclear sequestration can be another level of ribosomal protein regulation in eukaryotic cells.This may contribute to the regulation of cell growth and division.

In vivo labelling of functional ribosomes reveals spatial regulation during starvation in Podospora anserina

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Lalucque, Hervé; Silar, Philippe

2000-01-01

Background To date, in eukaryotes, ribosomal protein expression is known to be regulated at the transcriptional and/or translational levels. But other forms of regulation may be possible. Results Here, we report the successful tagging of functional ribosomal particles with a S7-GFP chimaeric protein, making it possible to observe in vivo ribosome dynamics in the filamentous fungus Podospora anserina. Microscopic observations revealed a novel kind of ribosomal protein regulation during the passage between cell growth and stationary phases, with a transient accumulation of ribosomal proteins and/or ribosome subunits in the nucleus, possibly the nucleolus, being observed at the beginning of stationary phase. Conclusion Nuclear sequestration can be another level of ribosomal protein regulation in eukaryotic cells.This may contribute to the regulation of cell growth and division. PMID:11112985

Executive functions and self-regulation.

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Hofmann, Wilhelm; Schmeichel, Brandon J; Baddeley, Alan D

2012-03-01

Self-regulation is a core aspect of adaptive human behavior that has been studied, largely in parallel, through the lenses of social and personality psychology as well as cognitive psychology. Here, we argue for more communication between these disciplines and highlight recent research that speaks to their connection. We outline how basic facets of executive functioning (working memory operations, behavioral inhibition, and task-switching) may subserve successful self-regulation. We also argue that temporary reductions in executive functions underlie many of the situational risk factors identified in the social psychological research on self-regulation and review recent evidence that the training of executive functions holds significant potential for improving poor self-regulation in problem populations. Copyright © 2012 Elsevier Ltd. All rights reserved.

Mucosal innate immune cells regulate both gut homeostasis and intestinal inflammation.

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Kurashima, Yosuke; Goto, Yoshiyuki; Kiyono, Hiroshi

2013-12-01

Continuous exposure of intestinal mucosal surfaces to diverse microorganisms and their metabolites reflects the biological necessity for a multifaceted, integrated epithelial and immune cell-mediated regulatory system. The development and function of the host cells responsible for the barrier function of the intestinal surface (e.g., M cells, Paneth cells, goblet cells, and columnar epithelial cells) are strictly regulated through both positive and negative stimulation by the luminal microbiota. Stimulation by damage-associated molecular patterns and commensal bacteria-derived microbe-associated molecular patterns provokes the assembly of inflammasomes, which are involved in maintaining the integrity of the intestinal epithelium. Mucosal immune cells located beneath the epithelium play critical roles in regulating both the mucosal barrier and the relative composition of the luminal microbiota. Innate lymphoid cells and mast cells, in particular, orchestrate the mucosal regulatory system to create a mutually beneficial environment for both the host and the microbiota. Disruption of mucosal homeostasis causes intestinal inflammation such as that seen in inflammatory bowel disease. Here, we review the recent research on the biological interplay among the luminal microbiota, epithelial cells, and mucosal innate immune cells in both healthy and pathological conditions. © 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

EZH2 regulates neuroblastoma cell differentiation via NTRK1 promoter epigenetic modifications.

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Li, Zhenghao; Takenobu, Hisanori; Setyawati, Amallia Nuggetsiana; Akita, Nobuhiro; Haruta, Masayuki; Satoh, Shunpei; Shinno, Yoshitaka; Chikaraishi, Koji; Mukae, Kyosuke; Akter, Jesmin; Sugino, Ryuichi P; Nakazawa, Atsuko; Nakagawara, Akira; Aburatani, Hiroyuki; Ohira, Miki; Kamijo, Takehiko

2018-05-01

The polycomb repressor complex 2 molecule EZH2 is now known to play a role in essential cellular processes, namely, cell fate decisions, cell cycle regulation, senescence, cell differentiation, and cancer development/progression. EZH2 inhibitors have recently been developed; however, their effectiveness and underlying molecular mechanisms in many malignancies have not yet been elucidated in detail. Although the functional role of EZH2 in tumorigenesis in neuroblastoma (NB) has been investigated, mutations of EZH2 have not been reported. A Kaplan-Meier analysis on the event free survival and overall survival of NB patients indicated that the high expression of EZH2 correlated with an unfavorable prognosis. In order to elucidate the functional roles of EZH2 in NB tumorigenesis and its aggressiveness, we knocked down EZH2 in NB cell lines using lentivirus systems. The knockdown of EZH2 significantly induced NB cell differentiation, e.g., neurite extension, and the neuronal differentiation markers, NF68 and GAP43. EZH2 inhibitors also induced NB cell differentiation. We performed a comprehensive transcriptome analysis using Human Gene Expression Microarrays and found that NTRK1 (TrkA) is one of the EZH2-related suppression targets. The depletion of NTRK1 canceled EZH2 knockdown-induced NB cell differentiation. Our integrative methylome, transcriptome, and chromatin immunoprecipitation assays using NB cell lines and clinical samples clarified that the NTRK1 P1 and P2 promoter regions were regulated differently by DNA methylation and EZH2-related histone modifications. The NTRK1 transcript variants 1/2, which were regulated by EZH2-related H3K27me3 modifications at the P1 promoter region, were strongly expressed in favorable, but not unfavorable NB. The depletion and inhibition of EZH2 successfully induced NTRK1 transcripts and functional proteins. Collectively, these results indicate that EZH2 plays important roles in preventing the differentiation of NB cells and also

Epigenetic regulation of vascular smooth muscle cell function in atherosclerosis.

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Findeisen, Hannes M; Kahles, Florian K; Bruemmer, Dennis

2013-04-01

Epigenetics involve heritable and acquired changes in gene transcription that occur independently of the DNA sequence. Epigenetic mechanisms constitute a hierarchic upper-level of transcriptional control through complex modifications of chromosomal components and nuclear structures. These modifications include, for example, DNA methylation or post-translational modifications of core histones; they are mediated by various chromatin-modifying enzymes; and ultimately they define the accessibility of a transcriptional complex to its target DNA. Integrating epigenetic mechanisms into the pathophysiologic concept of complex and multifactorial diseases such as atherosclerosis may significantly enhance our understanding of related mechanisms and provide promising therapeutic approaches. Although still in its infancy, intriguing scientific progress has begun to elucidate the role of epigenetic mechanisms in vascular biology, particularly in the control of smooth muscle cell phenotypes. In this review, we will summarize epigenetic pathways in smooth muscle cells, focusing on mechanisms involved in the regulation of vascular remodeling.

Overexpression of neurofilament H disrupts normal cell structure and function

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Szebenyi, Gyorgyi; Smith, George M.; Li, Ping; Brady, Scott T.

2002-01-01

Studying exogenously expressed tagged proteins in live cells has become a standard technique for evaluating protein distribution and function. Typically, expression levels of experimentally introduced proteins are not regulated, and high levels are often preferred to facilitate detection. However, overexpression of many proteins leads to mislocalization and pathologies. Therefore, for normative studies, moderate levels of expression may be more suitable. To understand better the dynamics of intermediate filament formation, transport, and stability in a healthy, living cell, we inserted neurofilament heavy chain (NFH)-green fluorescent protein (GFP) fusion constructs in adenoviral vectors with tetracycline (tet)-regulated promoters. This system allows for turning on or off the synthesis of NFH-GFP at a selected time, for a defined period, in a dose-dependent manner. We used this inducible system for live cell imaging of changes in filament structure and cell shape, motility, and transport associated with increasing NFH-GFP expression. Cells with low to intermediate levels of NFH-GFP were structurally and functionally similar to neighboring, nonexpressing cells. In contrast, overexpression led to pathological alterations in both filament organization and cell function. Copyright 2002 Wiley-Liss, Inc.

Ras proteins have multiple functions in vegetative cells of Dictyostelium.

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Bolourani, Parvin; Spiegelman, George; Weeks, Gerald

2010-11-01

During the aggregation of Dictyostelium cells, signaling through RasG is more important in regulating cyclic AMP (cAMP) chemotaxis, whereas signaling through RasC is more important in regulating the cAMP relay. However, RasC is capable of substituting for RasG for chemotaxis, since rasG⁻ cells are only partially deficient in chemotaxis, whereas rasC⁻/rasG⁻ cells are totally incapable of chemotaxis. In this study we have examined the possible functional overlap between RasG and RasC in vegetative cells by comparing the vegetative cell properties of rasG⁻, rasC⁻, and rasC⁻/rasG⁻ cells. In addition, since RasD, a protein not normally found in vegetative cells, is expressed in vegetative rasG⁻ and rasC⁻/rasG⁻ cells and appears to partially compensate for the absence of RasG, we have also examined the possible functional overlap between RasG and RasD by comparing the properties of rasG⁻ and rasC⁻/rasG⁻ cells with those of the mutant cells expressing higher levels of RasD. The results of these two lines of investigation show that RasD is capable of totally substituting for RasG for cytokinesis and growth in suspension, whereas RasC is without effect. In contrast, for chemotaxis to folate, RasC is capable of partially substituting for RasG, but RasD is totally without effect. Finally, neither RasC nor RasD is able to substitute for the role that RasG plays in regulating actin distribution and random motility. These specificity studies therefore delineate three distinct and none-overlapping functions for RasG in vegetative cells.

Ion Exchangers NHX1 and NHX2 Mediate Active Potassium Uptake into Vacuoles to Regulate Cell Turgor and Stomatal Function in Arabidopsis[W][OA

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Barragán, Verónica; Leidi, Eduardo O.; Andrés, Zaida; Rubio, Lourdes; De Luca, Anna; Fernández, José A.; Cubero, Beatriz; Pardo, José M.

2012-01-01

Intracellular NHX proteins are Na+,K+/H+ antiporters involved in K+ homeostasis, endosomal pH regulation, and salt tolerance. Proteins NHX1 and NHX2 are the two major tonoplast-localized NHX isoforms. Here, we show that NHX1 and NHX2 have similar expression patterns and identical biochemical activity, and together they account for a significant amount of the Na+,K+/H+ antiport activity in tonoplast vesicles. Reverse genetics showed functional redundancy of NHX1 and NHX2 genes. Growth of the double mutant nhx1 nhx2 was severely impaired, and plants were extremely sensitive to external K+. By contrast, nhx1 nhx2 mutants showed similar sensitivity to salinity stress and even greater rates of Na+ sequestration than the wild type. Double mutants had reduced ability to create the vacuolar K+ pool, which in turn provoked greater K+ retention in the cytosol, impaired osmoregulation, and compromised turgor generation for cell expansion. Genes NHX1 and NHX2 were highly expressed in guard cells, and stomatal function was defective in mutant plants, further compromising their ability to regulate water relations. Together, these results show that tonoplast-localized NHX proteins are essential for active K+ uptake at the tonoplast, for turgor regulation, and for stomatal function. PMID:22438021

Fip1 regulates mRNA alternative polyadenylation to promote stem cell self-renewal

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Lackford, Brad; Yao, Chengguo; Charles, Georgette M; Weng, Lingjie; Zheng, Xiaofeng; Choi, Eun-A; Xie, Xiaohui; Wan, Ji; Xing, Yi; Freudenberg, Johannes M; Yang, Pengyi; Jothi, Raja; Hu, Guang; Shi, Yongsheng

2014-01-01

mRNA alternative polyadenylation (APA) plays a critical role in post-transcriptional gene control and is highly regulated during development and disease. However, the regulatory mechanisms and functional consequences of APA remain poorly understood. Here, we show that an mRNA 3′ processing factor, Fip1, is essential for embryonic stem cell (ESC) self-renewal and somatic cell reprogramming. Fip1 promotes stem cell maintenance, in part, by activating the ESC-specific APA profiles to ensure the optimal expression of a specific set of genes, including critical self-renewal factors. Fip1 expression and the Fip1-dependent APA program change during ESC differentiation and are restored to an ESC-like state during somatic reprogramming. Mechanistically, we provide evidence that the specificity of Fip1-mediated APA regulation depends on multiple factors, including Fip1-RNA interactions and the distance between APA sites. Together, our data highlight the role for post-transcriptional control in stem cell self-renewal, provide mechanistic insight on APA regulation in development, and establish an important function for APA in cell fate specification. PMID:24596251

An RNA-binding protein, Qki5, regulates embryonic neural stem cells through pre-mRNA processing in cell adhesion signaling.

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Hayakawa-Yano, Yoshika; Suyama, Satoshi; Nogami, Masahiro; Yugami, Masato; Koya, Ikuko; Furukawa, Takako; Zhou, Li; Abe, Manabu; Sakimura, Kenji; Takebayashi, Hirohide; Nakanishi, Atsushi; Okano, Hideyuki; Yano, Masato

2017-09-15

Cell type-specific transcriptomes are enabled by the action of multiple regulators, which are frequently expressed within restricted tissue regions. In the present study, we identify one such regulator, Quaking 5 (Qki5), as an RNA-binding protein (RNABP) that is expressed in early embryonic neural stem cells and subsequently down-regulated during neurogenesis. mRNA sequencing analysis in neural stem cell culture indicates that Qki proteins play supporting roles in the neural stem cell transcriptome and various forms of mRNA processing that may result from regionally restricted expression and subcellular localization. Also, our in utero electroporation gain-of-function study suggests that the nuclear-type Qki isoform Qki5 supports the neural stem cell state. We next performed in vivo transcriptome-wide protein-RNA interaction mapping to search for direct targets of Qki5 and elucidate how Qki5 regulates neural stem cell function. Combined with our transcriptome analysis, this mapping analysis yielded a bona fide map of Qki5-RNA interaction at single-nucleotide resolution, the identification of 892 Qki5 direct target genes, and an accurate Qki5-dependent alternative splicing rule in the developing brain. Last, our target gene list provides the first compelling evidence that Qki5 is associated with specific biological events; namely, cell-cell adhesion. This prediction was confirmed by histological analysis of mice in which Qki proteins were genetically ablated, which revealed disruption of the apical surface of the lateral wall in the developing brain. These data collectively indicate that Qki5 regulates communication between neural stem cells by mediating numerous RNA processing events and suggest new links between splicing regulation and neural stem cell states. © 2017 Hayakawa-Yano et al.; Published by Cold Spring Harbor Laboratory Press.

Zfp206 regulates ES cell gene expression and differentiation.

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Zhang, Wen; Walker, Emily; Tamplin, Owen J; Rossant, Janet; Stanford, William L; Hughes, Timothy R

2006-01-01

Understanding transcriptional regulation in early developmental stages is fundamental to understanding mammalian development and embryonic stem (ES) cell properties. Expression surveys suggest that the putative SCAN-Zinc finger transcription factor Zfp206 is expressed specifically in ES cells [Zhang,W., Morris,Q.D., Chang,R., Shai,O., Bakowski,M.A., Mitsakakis,N., Mohammad,N., Robinson,M.D., Zirngibl,R., Somogyi,E. et al., (2004) J. Biol., 3, 21; Brandenberger,R., Wei,H., Zhang,S., Lei,S., Murage,J., Fisk,G.J., Li,Y., Xu,C., Fang,R., Guegler,K. et al., (2004) Nat. Biotechnol., 22, 707-716]. Here, we confirm this observation, and we show that ZFP206 expression decreases rapidly upon differentiation of cultured mouse ES cells, and during development of mouse embryos. We find that there are at least six isoforms of the ZFP206 transcript, the longest being predominant. Overexpression and depletion experiments show that Zfp206 promotes formation of undifferentiated ES cell clones, and positively regulates abundance of a very small set of transcripts whose expression is also specific to ES cells and the two- to four-cell stages of preimplantation embryos. This set includes members of the Zscan4, Thoc4, Tcstv1 and eIF-1A gene families, none of which have been functionally characterized in vivo but whose members include apparent transcription factors, RNA-binding proteins and translation factors. Together, these data indicate that Zfp206 is a regulator of ES cell differentiation that controls a set of genes expressed very early in development, most of which themselves appear to be regulators.

Regulation of Histone Acetyltransferase TIP60 Function by Histone Deacetylase 3

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Yi, Jingjie; Huang, Xiangyang; Yang, Yuxia; Zhu, Wei-Guo; Gu, Wei; Luo, Jianyuan

2014-01-01

The key member of the MOZ (monocyticleukaemia zinc finger protein), Ybf2/Sas3, Sas2, and TIP60 acetyltransferases family, Tat-interactive protein, 60 kD (TIP60), tightly modulates a wide array of cellular processes, including chromatin remodeling, gene transcription, apoptosis, DNA repair, and cell cycle arrest. The function of TIP60 can be regulated by SIRT1 through deacetylation. Here we found that TIP60 can also be functionally regulated by HDAC3. We identified six lysine residues as its autoacetylation sites. Mutagenesis of these lysines to arginines completely abolishes the autoacetylation of TIP60. Overexpression of HDAC3 increases TIP60 ubiquitination levels. However, unlike SIRT1, HDAC3 increased the half-life of TIP60. Further study found that HDAC3 colocalized with TIP60 both in the nucleus and the cytoplasm, which could be the reason why HDAC3 can stabilize TIP60. The deacetylation of TIP60 by both SIRT1 and HDAC3 reduces apoptosis induced by DNA damage. Knockdown of HDAC3 in cells increased TIP60 acetylation levels and increased apoptosis after DNA damage. Together, our findings provide a better understanding of TIP60 regulation mechanisms, which is a significant basis for further studies of its cellular functions. PMID:25301942

Longitudinal Changes in Insulin Resistance, Beta-Cell Function and Glucose Regulation Status in Prediabetes.

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Kim, Chul-Hee; Kim, Hong-Kyu; Kim, Eun-Hee; Bae, Sung-Jin; Choe, Jaewon; Park, Joong-Yeol

2018-01-01

The changes in insulin resistance and insulin secretion and their association with changes in glucose regulation status in Asians with prediabetes remain uncertain. We included Korean adults (aged 20-79 years) with prediabetes who underwent routine medical check-ups at a mean interval of 5 years. Prediabetes was defined as fasting plasma glucose (FPG) 5.6-6.9mmol/l or HbA1c 5.7-6.4% (39-46mmol/mol). Insulin resistance (HOMA-IR) and beta-cell function (HOMA-%B) indices were assessed by homeostasis model assessment. Incident diabetes was defined as FPG ≥ 7.0mmol/l, HbA1c ≥ 6.5% (48mmol/mol), or initiation of antidiabetic medications. Among the 7,208 participants with prediabetes, 4,410 (61.2%) remained as prediabetes (control group), 2,123 (29.5%) reverted to normal glucose regulation (regressors), and 675 (9.4%) progressed to type 2 diabetes (progressors) after 5 years. Compared with the control group, the progressors had higher baseline HOMA-IR (2.48 ± 1.45 versus 2.06 ± 1.20, P prediabetes, longitudinal change in insulin resistance was the predominant factor in Koreans. Copyright © 2018 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.

Cell Cycle Regulation by Alternative Polyadenylation of CCND1.

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Wang, Qiong; He, Guopei; Hou, Mengmeng; Chen, Liutao; Chen, Shangwu; Xu, Anlong; Fu, Yonggui

2018-05-01

Global shortening of 3'UTRs by alternative polyadenylation (APA) has been observed in cancer cells. However, the role of APA in cancer remains unknown. CCND1 is a proto-oncogene that regulates progression through the G1-S phase of the cell cycle; moreover, it has been observed to be switching to proximal APA sites in cancer cells. To investigate the biological function of the APA of CCND1, we edited the weak poly(A) signal (PAS) of the proximal APA site to a canonical PAS using the CRISPR/Cas9 method, which can force the cells to use a proximal APA site. Cell cycle profiling and proliferation assays revealed that the proximal APA sites of CCND1 accelerated the cell cycle and promoted cell proliferation, but UTR-APA and CR-APA act via different molecular mechanisms. These results indicate that PAS editing with CRISPR/Cas9 provides a good method by which to study the biological function of APA.

Versatile function of the circadian protein CIPC as a regulator of Erk activation

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Matsunaga, Ryota; Nishino, Tasuku; Yokoyama, Atsushi; Nakashima, Akio; Kikkawa, Ushio; Konishi, Hiroaki

2016-01-01

The CLOCK-interacting protein, Circadian (CIPC), has been identified as an additional negative-feedback regulator of the circadian clock. However, recent study on CIPC knockout mice has shown that CIPC is not critically required for basic circadian clock function, suggesting other unknown biological roles for CIPC. In this study, we focused on the cell cycle dependent nuclear-cytoplasmic shuttling function of CIPC and on identifying its binding proteins. Lys186 and 187 were identified as the essential amino acid residues within the nuclear localization signal (NLS) of CIPC. We identified CIPC-binding proteins such as the multifunctional enzyme CAD protein (carbamoyl-phosphate synthetase 2, aspartate transcarbamoylase, and dihydroorotase), which is a key enzyme for de novo pyrimidine synthesis. Compared to control cells, HEK293 cells overexpressing wild-type CIPC showed suppressed cell proliferation and retardation of cell cycle. We also found that PMA-induced Erk activation was inhibited with expression of wild-type CIPC. In contrast, the NLS mutant of CIPC, which reduced the ability of CIPC to translocate into the nucleus, did not exhibit these biological effects. Since CAD and Erk have significant roles in cell proliferation and cell cycle, CIPC may work as a cell cycle regulator by interacting with these binding proteins. - Highlights: • CIPC is a cell cycle dependent nuclear-cytoplasmic shuttling protein. • K186 and 187are the essential amino acid residues within the NLS of CIPC. • CAD was identified as a novel CIPC-binding protein. • CIPC might regulate the activity and translocation of CAD in the cells.

Versatile function of the circadian protein CIPC as a regulator of Erk activation

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Matsunaga, Ryota; Nishino, Tasuku [Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima 727-0023 (Japan); Yokoyama, Atsushi [Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575 (Japan); Nakashima, Akio; Kikkawa, Ushio [Biosignal Research Center, Kobe University, Kobe 657-8501 (Japan); Konishi, Hiroaki, E-mail: hkonishi@pu-hiroshima.ac.jp [Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima 727-0023 (Japan)

2016-01-15

The CLOCK-interacting protein, Circadian (CIPC), has been identified as an additional negative-feedback regulator of the circadian clock. However, recent study on CIPC knockout mice has shown that CIPC is not critically required for basic circadian clock function, suggesting other unknown biological roles for CIPC. In this study, we focused on the cell cycle dependent nuclear-cytoplasmic shuttling function of CIPC and on identifying its binding proteins. Lys186 and 187 were identified as the essential amino acid residues within the nuclear localization signal (NLS) of CIPC. We identified CIPC-binding proteins such as the multifunctional enzyme CAD protein (carbamoyl-phosphate synthetase 2, aspartate transcarbamoylase, and dihydroorotase), which is a key enzyme for de novo pyrimidine synthesis. Compared to control cells, HEK293 cells overexpressing wild-type CIPC showed suppressed cell proliferation and retardation of cell cycle. We also found that PMA-induced Erk activation was inhibited with expression of wild-type CIPC. In contrast, the NLS mutant of CIPC, which reduced the ability of CIPC to translocate into the nucleus, did not exhibit these biological effects. Since CAD and Erk have significant roles in cell proliferation and cell cycle, CIPC may work as a cell cycle regulator by interacting with these binding proteins. - Highlights: • CIPC is a cell cycle dependent nuclear-cytoplasmic shuttling protein. • K186 and 187are the essential amino acid residues within the NLS of CIPC. • CAD was identified as a novel CIPC-binding protein. • CIPC might regulate the activity and translocation of CAD in the cells.

Cell cycle regulation of hematopoietic stem or progenitor cells.

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Hao, Sha; Chen, Chen; Cheng, Tao

2016-05-01

The highly regulated process of blood production is achieved through the hierarchical organization of hematopoietic stem cell (HSC) subsets and their progenies, which differ in self-renewal and differentiation potential. Genetic studies in mice have demonstrated that cell cycle is tightly controlled by the complex interplay between extrinsic cues and intrinsic regulatory pathways involved in HSC self-renewal and differentiation. Deregulation of these cellular programs may transform HSCs or hematopoietic progenitor cells (HPCs) into disease-initiating stem cells, and can result in hematopoietic malignancies such as leukemia. While previous studies have shown roles for some cell cycle regulators and related signaling pathways in HSCs and HPCs, a more complete picture regarding the molecular mechanisms underlying cell cycle regulation in HSCs or HPCs is lacking. Based on accumulated studies in this field, the present review introduces the basic components of the cell cycle machinery and discusses their major cellular networks that regulate the dormancy and cell cycle progression of HSCs. Knowledge on this topic would help researchers and clinicians to better understand the pathogenesis of relevant blood disorders and to develop new strategies for therapeutic manipulation of HSCs.

Electrical stimulation as a biomimicry tool for regulating muscle cell behavior.

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Ahadian, Samad; Ostrovidov, Serge; Hosseini, Vahid; Kaji, Hirokazu; Ramalingam, Murugan; Bae, Hojae; Khademhosseini, Ali

2013-01-01

There is a growing need to understand muscle cell behaviors and to engineer muscle tissues to replace defective tissues in the body. Despite a long history of the clinical use of electric fields for muscle tissues in vivo, electrical stimulation (ES) has recently gained significant attention as a powerful tool for regulating muscle cell behaviors in vitro. ES aims to mimic the electrical environment of electroactive muscle cells (e.g., cardiac or skeletal muscle cells) by helping to regulate cell-cell and cell-extracellular matrix (ECM) interactions. As a result, it can be used to enhance the alignment and differentiation of skeletal or cardiac muscle cells and to aid in engineering of functional muscle tissues. Additionally, ES can be used to control and monitor force generation and electrophysiological activity of muscle tissues for bio-actuation and drug-screening applications in a simple, high-throughput, and reproducible manner. In this review paper, we briefly describe the importance of ES in regulating muscle cell behaviors in vitro, as well as the major challenges and prospective potential associated with ES in the context of muscle tissue engineering.

Hemidesmosomal linker proteins regulate cell motility, invasion and tumorigenicity in oral squamous cell carcinoma derived cells.

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Chaudhari, Pratik Rajeev; Charles, Silvania Emlit; D'Souza, Zinia Charlotte; Vaidya, Milind Murlidhar

2017-11-15

BPAG1e and Plectin are hemidesmosomal linker proteins which anchor intermediate filament proteins to the cell surface through β4 integrin. Recent reports indicate that these proteins play a role in various cellular processes apart from their known anchoring function. However, the available literature is inconsistent. Further, the previous study from our laboratory suggested that Keratin8/18 pair promotes cell motility and tumor progression by deregulating β4 integrin signaling in oral squamous cell carcinoma (OSCC) derived cells. Based on these findings, we hypothesized that linker proteins may have a role in neoplastic progression of OSCC. Downregulation of hemidesmosomal linker proteins in OSCC derived cells resulted in reduced cell migration accompanied by alterations in actin organization. Further, decreased MMP9 activity led to reduced cell invasion in linker proteins knockdown cells. Moreover, loss of these proteins resulted in reduced tumorigenic potential. SWATH analysis demonstrated upregulation of N-Myc downstream regulated gene 1 (NDRG1) in linker proteins downregulated cells as compared to vector control cells. Further, the defects in phenotype upon linker proteins ablation were rescued upon loss of NDRG1 in linker proteins knockdown background. These data together indicate that hemidesmosomal linker proteins regulate cell motility, invasion and tumorigenicity possibly through NDRG1 in OSCC derived cells. Copyright © 2017 Elsevier Inc. All rights reserved.

Widespread immunological functions of mast cells: fact or fiction?

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Rodewald, Hans-Reimer; Feyerabend, Thorsten B

2012-07-27

Immunological functions of mast cells are currently considered to be much broader than the original role of mast cells in IgE-driven allergic disease. The spectrum of proposed mast cell functions includes areas as diverse as the regulation of innate and adaptive immune responses, protective immunity against viral, microbial, and parasitic pathogens, autoimmunity, tolerance to graft rejection, promotion of or protection from cancer, wound healing, angiogenesis, cardiovascular diseases, diabetes, obesity, and others. The vast majority of in vivo mast cell data have been based on mast cell-deficient Kit mutant mice. However, work in new mouse mutants with unperturbed Kit function, which have a surprisingly normal immune system, has failed to corroborate some key immunological aspects, formerly attributed to mast cells. Here, we consider the implications of these recent developments for the state of the field as well as for future work, aiming at deciphering the physiological functions of mast cells. Copyright © 2012 Elsevier Inc. All rights reserved.

Allergic TH2 Response Governed by B-Cell Lymphoma 6 Function in Naturally Occurring Memory Phenotype CD4+ T Cells.

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Ogasawara, Takashi; Kohashi, Yuko; Ikari, Jun; Taniguchi, Toshibumi; Tsuruoka, Nobuhide; Watanabe-Takano, Haruko; Fujimura, Lisa; Sakamoto, Akemi; Hatano, Masahiko; Hirata, Hirokuni; Fukushima, Yasutsugu; Fukuda, Takeshi; Kurasawa, Kazuhiro; Tatsumi, Koichiro; Tokuhisa, Takeshi; Arima, Masafumi

2018-01-01

Transcriptional repressor B-cell lymphoma 6 (Bcl6) appears to regulate T H 2 immune responses in allergies, but its precise role is unclear. We previously reported that Bcl6 suppressed IL-4 production in naïve CD4 + T cell-derived memory T H 2 cells. To investigate Bcl6 function in allergic responses in naturally occurring memory phenotype CD4 + T (MPT) cells and their derived T H 2 (MPT H 2) cells, Bcl6 -manipulated mice , highly conserved intron enhancer (hcIE)-deficient mice , and reporter mice for conserved noncoding sequence 2 (CNS2) 3' distal enhancer region were used to elucidate Bcl6 function in MPT cells. The molecular mechanisms of Bcl6-mediated T H 2 cytokine gene regulation were elucidated using cellular and molecular approaches. Bcl6 function in MPT cells was determined using adoptive transfer to naïve mice, which were assessed for allergic airway inflammation. Bcl6 suppressed IL-4 production in MPT and MPT H 2 cells by suppressing CNS2 enhancer activity. Bcl6 downregulated Il4 expression in MPT H 2 cells, but not MPT cells, by suppressing hcIE activity. The inhibitory functions of Bcl6 in MPT and MPT H 2 cells attenuated allergic responses. Bcl6 is a critical regulator of IL-4 production by MPT and MPT H 2 cells in T H 2 immune responses related to the pathogenesis of allergies.

Allergic TH2 Response Governed by B-Cell Lymphoma 6 Function in Naturally Occurring Memory Phenotype CD4+ T Cells

Science.gov (United States)

Ogasawara, Takashi; Kohashi, Yuko; Ikari, Jun; Taniguchi, Toshibumi; Tsuruoka, Nobuhide; Watanabe-Takano, Haruko; Fujimura, Lisa; Sakamoto, Akemi; Hatano, Masahiko; Hirata, Hirokuni; Fukushima, Yasutsugu; Fukuda, Takeshi; Kurasawa, Kazuhiro; Tatsumi, Koichiro; Tokuhisa, Takeshi; Arima, Masafumi

2018-01-01

Transcriptional repressor B-cell lymphoma 6 (Bcl6) appears to regulate TH2 immune responses in allergies, but its precise role is unclear. We previously reported that Bcl6 suppressed IL-4 production in naïve CD4+ T cell-derived memory TH2 cells. To investigate Bcl6 function in allergic responses in naturally occurring memory phenotype CD4+ T (MPT) cells and their derived TH2 (MPTH2) cells, Bcl6-manipulated mice, highly conserved intron enhancer (hcIE)-deficient mice, and reporter mice for conserved noncoding sequence 2 (CNS2) 3′ distal enhancer region were used to elucidate Bcl6 function in MPT cells. The molecular mechanisms of Bcl6-mediated TH2 cytokine gene regulation were elucidated using cellular and molecular approaches. Bcl6 function in MPT cells was determined using adoptive transfer to naïve mice, which were assessed for allergic airway inflammation. Bcl6 suppressed IL-4 production in MPT and MPTH2 cells by suppressing CNS2 enhancer activity. Bcl6 downregulated Il4 expression in MPTH2 cells, but not MPT cells, by suppressing hcIE activity. The inhibitory functions of Bcl6 in MPT and MPTH2 cells attenuated allergic responses. Bcl6 is a critical regulator of IL-4 production by MPT and MPTH2 cells in TH2 immune responses related to the pathogenesis of allergies. PMID:29696026

Regulation of cell proliferation and apoptosis in neuroblastoma cells by ccp1, a FGF2 downstream gene

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Inman Gareth J

2010-11-01

Full Text Available Abstract Background Coiled-coil domain containing 115 (Ccdc115 or coiled coil protein-1 (ccp1 was previously identified as a downstream gene of Fibroblast Growth Factor 2 (FGF2 highly expressed in embryonic and adult brain. However, its function has not been characterised to date. Here we hypothesized that ccp1 may be a downstream effecter of FGF2, promoting cell proliferation and protecting from apoptosis. Methods Forced ccp1 expression in mouse embryonic fibroblast (MEF and neuroblastoma SK-N-SH cell line, as well as down-regulation of ccp1 expression by siRNA in NIH3T3, was used to characterize the role of ccp1. Results Ccp1 over-expression increased cell proliferation, whereas down-regulation of ccp1 expression reduced it. Ccp1 was able to increase cell proliferation in the absence of serum. Furthermore, ccp1 reduced apoptosis upon withdrawal of serum in SK-N-SH. The mitogen-activated protein kinase (MAPK or ERK Kinase (MEK inhibitor, U0126, only partially inhibited the ccp1-dependent BrdU incorporation, indicating that other signaling pathway may be involved in ccp1-induced cell proliferation. Induction of Sprouty (SPRY upon FGF2 treatment was accelerated in ccp1 over-expressing cells. Conclusions All together, the results showed that ccp1 regulates cell number by promoting proliferation and suppressing cell death. FGF2 was shown to enhance the effects of ccp1, however, it is likely that other mitogenic factors present in the serum can also enhance the effects. Whether these effects are mediated by FGF2 influencing the ccp1 function or by increasing the ccp1 expression level is still unclear. At least some of the proliferative regulation by ccp1 is mediated by MAPK, however other signaling pathways are likely to be involved.

Transcription factor RBP-J-mediated signalling regulates basophil immunoregulatory function in mouse asthma model.

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Qu, Shuo-Yao; He, Ya-Long; Zhang, Jian; Wu, Chang-Gui

2017-09-01

Basophils (BA) play an important role in the promotion of aberrant T helper type 2 (Th2) immune responses in asthma. It is not only the effective cell, but also modulates the initiation of Th2 immune responses. We earlier demonstrated that Notch signalling regulates the biological function of BAin vitro. However, whether this pathway plays the same role in vivo is not clear. The purpose of the present study was to investigate the effect of Notch signalling on BA function in the regulation of allergic airway inflammation in a murine model of asthma. Bone marrow BA were prepared by bone marrow cell culture in the presence of recombinant interleukin-3 (rIL-3; 300 pg/ml) for 7 days, followed by isolation of the CD49b + microbeads. The recombination signal binding protein J (RBP-J -/- ) BA were co-cultured with T cells, and the supernatant and the T-cell subtypes were examined. The results indicated disruption of the capacity of BA for antigen presentation alongside an up-regulation of the immunoregulatory function. This was possibly due to the low expression of OX40L in the RBP-J -/- BA. Basophils were adoptively transferred to ovalbumin-sensitized recipient mice, to establish an asthma model. Lung pathology, cytokine profiles of brobchoalveolar fluid, airway hyperactivity and the absolute number of Th1/Th2 cells in lungs were determined. Overall, our results indicate that the RBP-J-mediated Notch signalling is critical for BA-dependent immunoregulation. Deficiency of RBP-J influences the immunoregulatory functions of BA, which include activation of T cells and their differentiation into T helper cell subtypes. The Notch signalling pathway is a potential therapeutic target for BA-based immunotherapy against asthma. © 2017 John Wiley & Sons Ltd.

Hsa-let-7a functions as a tumor suppressor in renal cell carcinoma cell lines by targeting c-myc

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Liu, Yongchao; Yin, Bingde; Zhang, Changcun; Zhou, Libin [Department of Urology, Shanghai First People' s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200080 (China); Fan, Jie, E-mail: jief67@sina.com [Department of Urology, Shanghai First People' s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200080 (China)

2012-01-06

Highlights: Black-Right-Pointing-Pointer This study is the first to test the let-7a/c-myc loop in renal cell carcinoma cell lines. Black-Right-Pointing-Pointer Let-7a down-regulated c-myc in three renal cell carcinoma cell lines. Black-Right-Pointing-Pointer c-myc target genes were down-regulated because of the let-7a-mediated down-regulation of c-myc. Black-Right-Pointing-Pointer The let-7a/c-myc loop has a significant function in renal cell carcinoma cell lines. -- Abstract: Widespread functions of the c-myc pathway play a crucial role in renal cell carcinoma (RCC) carcinogenesis. Thus, we evaluated the connection between proto-oncogenic c-myc and anti-neoplastic hsa-let-7a (let-7a) in RCC cell lines. The levels of c-myc and let-7a in 3 RCC cell lines (769P, Caki-1 and 786O) were measured after transfecting the cells with let-7a mimics or a negative control. The change in c-myc protein level was confirmed by Western blot. The anti-neoplastic function of let-7a was evaluated using cell counting kit-8 (CCK-8) for proliferation analysis and cell flow cytometry for cell cycle analysis. The changes of downstream targets of c-myc were measured using reverse transcription quantitative real-time PCR (qRT-PCR). Our results suggest for the first time that let-7a acts as a tumor suppressor in RCC cell lines by down-regulating c-myc and c-myc target genes such as proliferating cell nuclear antigen (PCNA), cyclin D1 (CCND1) and the miR17-92 cluster, which is accompanied by proliferation inhibition and cell cycle arrest.

Genome-wide RNAi Screen Identifies Networks Involved in Intestinal Stem Cell Regulation in Drosophila

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Xiankun Zeng

2015-02-01

Full Text Available The intestinal epithelium is the most rapidly self-renewing tissue in adult animals and maintained by intestinal stem cells (ISCs in both Drosophila and mammals. To comprehensively identify genes and pathways that regulate ISC fates, we performed a genome-wide transgenic RNAi screen in adult Drosophila intestine and identified 405 genes that regulate ISC maintenance and lineage-specific differentiation. By integrating these genes into publicly available interaction databases, we further developed functional networks that regulate ISC self-renewal, ISC proliferation, ISC maintenance of diploid status, ISC survival, ISC-to-enterocyte (EC lineage differentiation, and ISC-to-enteroendocrine (EE lineage differentiation. By comparing regulators among ISCs, female germline stem cells, and neural stem cells, we found that factors related to basic stem cell cellular processes are commonly required in all stem cells, and stem-cell-specific, niche-related signals are required only in the unique stem cell type. Our findings provide valuable insights into stem cell maintenance and lineage-specific differentiation.

miR-99 regulates normal and malignant hematopoietic stem cell self-renewal.

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Khalaj, Mona; Woolthuis, Carolien M; Hu, Wenhuo; Durham, Benjamin H; Chu, S Haihua; Qamar, Sarah; Armstrong, Scott A; Park, Christopher Y

2017-07-21

The microRNA-99 ( miR-99 ) family comprises a group of broadly conserved microRNAs that are highly expressed in hematopoietic stem cells (HSCs) and acute myeloid leukemia stem cells (LSCs) compared with their differentiated progeny. Herein, we show that miR-99 regulates self-renewal in both HSCs and LSCs. miR-99 maintains HSC long-term reconstitution activity by inhibiting differentiation and cell cycle entry. Moreover, miR-99 inhibition induced LSC differentiation and depletion in an MLL-AF9-driven mouse model of AML, leading to reduction in leukemia-initiating activity and improved survival in secondary transplants. Confirming miR-99 's role in established AML, miR-99 inhibition induced primary AML patient blasts to undergo differentiation. A forward genetic shRNA library screen revealed Hoxa1 as a critical mediator of miR-99 function in HSC maintenance, and this observation was independently confirmed in both HSCs and LSCs. Together, these studies demonstrate the importance of noncoding RNAs in the regulation of HSC and LSC function and identify miR-99 as a critical regulator of stem cell self-renewal. © 2017 Khalaj et al.

Regulation of cell wall biosynthesis.

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Zhong, Ruiqin; Ye, Zheng-Hua

2007-12-01

Plant cell walls differ in their amount and composition among various cell types and even in different microdomains of the wall of a given cell. Plants must have evolved regulatory mechanisms controlling biosynthesis, targeted secretion, and assembly of wall components to achieve the heterogeneity in cell walls. A number of factors, including hormones, the cytoskeleton, glycosylphosphatidylinositol-anchored proteins, phosphoinositides, and sugar nucleotide supply, have been implicated in the regulation of cell wall biosynthesis or deposition. In the past two years, there have been important discoveries in transcriptional regulation of secondary wall biosynthesis. Several transcription factors in the NAC and MYB families have been shown to be the key switches for activation of secondary wall biosynthesis. These studies suggest a transcriptional network comprised of a hierarchy of transcription factors is involved in regulating secondary wall biosynthesis. Further investigation and integration of the regulatory players participating in the making of cell walls will certainly lead to our understanding of how wall amounts and composition are controlled in a given cell type. This may eventually allow custom design of plant cell walls on the basis of our needs.

β-Catenin Is a Positive Regulator of Estrogen Receptor-α Function in Breast Cancer Cells

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Gupta, Nibedita; Schmitt, Fee; Grebhardt, Sina; Mayer, Doris, E-mail: d.mayer@dkfz.de [Hormones and Signal Transduction Group, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 581, 69120 Heidelberg (Germany)

2011-07-22

Estrogen receptor-alpha (ERα) is a key factor in the development of breast cancer in humans. The expression and activity of ERα is regulated by a multitude of intracellular and extracellular signals. Here we show a cross-talk between β-catenin and ERα in human breast cancer cells. Knockdown of β-catenin by RNAi resulted in significant reduction of ERα mRNA and/or protein levels in MCF-7, T-47D, and BT-474 breast cancer cells and in significant reduction of estradiol-induced expression of the ERα target genes pS2 and GREB1. In addition β-catenin silencing resulted in significant decrease of growth of MCF-7 cells both in the absence and presence of estradiol. β-catenin and ERα could not be co-immunoprecipitated by ERα antibodies from lysates of E2-treated or untreated cells suggesting lack of direct physical interaction. It is concluded that β-catenin is a positive regulator of ERα mRNA and protein expression.

Role of Cytokine-Induced Glycosylation Changes in Regulating Cell Interactions and Cell Signaling in Inflammatory Diseases and Cancer

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Justine H. Dewald

2016-11-01

Full Text Available Glycosylation is one of the most important modifications of proteins and lipids, and cell surface glycoconjugates are thought to play important roles in a variety of biological functions including cell-cell and cell-substrate interactions, bacterial adhesion, cell immunogenicity and cell signaling. Alterations of glycosylation are observed in number of diseases such as cancer and chronic inflammation. In that context, pro-inflammatory cytokines have been shown to modulate cell surface glycosylation by regulating the expression of glycosyltransferases involved in the biosynthesis of carbohydrate chains. These changes in cell surface glycosylation are also known to regulate cell signaling and could contribute to disease pathogenesis. This review summarizes our current knowledge of the glycosylation changes induced by pro-inflammatory cytokines, with a particular focus on cancer and cystic fibrosis, and their consequences on cell interactions and signaling.

The ROCK isoforms differentially regulate the morphological characteristics of carcinoma cells.

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Jerrell, Rachel J; Leih, Mitchell J; Parekh, Aron

2017-06-26

Rho-associated kinase (ROCK) activity drives cell migration via actomyosin contractility. During invasion, individual cancer cells can transition between 2 modes of migration, mesenchymal and amoeboid. Changes in ROCK activity can cause a switch between these migration phenotypes which are defined by distinct morphologies. However, recent studies have shown that the ROCK isoforms are not functionally redundant as previously thought. Therefore, it is unclear whether the ROCK isoforms play different roles in regulating migration phenotypes. Here, we found that ROCK1 and ROCK2 differentially regulate carcinoma cell morphology resulting in intermediate phenotypes that share some mesenchymal and amoeboid characteristics. These findings suggest that the ROCK isoforms play unique roles in the phenotypic plasticity of mesenchymal carcinoma cells which may have therapeutic implications.

Epigenetic Regulation of Epidermal Stem Cell Biomarkers and Their Role in Wound Healing

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Sabita N. Saldanha

2015-12-01

Full Text Available As an actively renewable tissue, changes in skin architecture are subjected to the regulation of stem cells that maintain the population of cells responsible for the formation of epidermal layers. Stems cells retain their self-renewal property and express biomarkers that are unique to this population. However, differential regulation of the biomarkers can initiate the pathway of terminal cell differentiation. Although, pockets of non-clarity in stem cell maintenance and differentiation in skin still exist, the influence of epigenetics in epidermal stem cell functions and differentiation in skin homeostasis and wound healing is clearly evident. The focus of this review is to discuss the epigenetic regulation of confirmed and probable epidermal stem cell biomarkers in epidermal stratification of normal skin and in diseased states. The role of epigenetics in wound healing, especially in diseased states of diabetes and cancer, will also be conveyed.

Specification of Drosophila corpora cardiaca neuroendocrine cells from mesoderm is regulated by Notch signaling.

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Sangbin Park

2011-08-01

Full Text Available Drosophila neuroendocrine cells comprising the corpora cardiaca (CC are essential for systemic glucose regulation and represent functional orthologues of vertebrate pancreatic α-cells. Although Drosophila CC cells have been regarded as developmental orthologues of pituitary gland, the genetic regulation of CC development is poorly understood. From a genetic screen, we identified multiple novel regulators of CC development, including Notch signaling factors. Our studies demonstrate that the disruption of Notch signaling can lead to the expansion of CC cells. Live imaging demonstrates localized emergence of extra precursor cells as the basis of CC expansion in Notch mutants. Contrary to a recent report, we unexpectedly found that CC cells originate from head mesoderm. We show that Tinman expression in head mesoderm is regulated by Notch signaling and that the combination of Daughterless and Tinman is sufficient for ectopic CC specification in mesoderm. Understanding the cellular, genetic, signaling, and transcriptional basis of CC cell specification and expansion should accelerate discovery of molecular mechanisms regulating ontogeny of organs that control metabolism.

Redox Regulation of Endothelial Cell Fate

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Song, Ping; Zou, Ming-Hui

2014-01-01

Endothelial cells (ECs) are present throughout blood vessels and have variable roles in both physiological and pathological settings. EC fate is altered and regulated by several key factors in physiological or pathological conditions. Reactive nitrogen species and reactive oxygen species derived from NAD(P)H oxidases, mitochondria, or nitric oxide-producing enzymes are not only cytotoxic but also compose a signaling network in the redox system. The formation, actions, key molecular interactions, and physiological and pathological relevance of redox signals in ECs remain unclear. We review the identities, sources, and biological actions of oxidants and reductants produced during EC function or dysfunction. Further, we discuss how ECs shape key redox sensors and examine the biological functions, transcriptional responses, and post-translational modifications evoked by the redox system in ECs. We summarize recent findings regarding the mechanisms by which redox signals regulate the fate of ECs and address the outcome of altered EC fate in health and disease. Future studies will examine if the redox biology of ECs can be targeted in pathophysiological conditions. PMID:24633153

Dendritic cell maturation: functional specialization through signaling specificity and transcriptional programming.

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Dalod, Marc; Chelbi, Rabie; Malissen, Bernard; Lawrence, Toby

2014-05-16

Dendritic cells (DC) are key regulators of both protective immune responses and tolerance to self-antigens. Soon after their discovery in lymphoid tissues by Steinman and Cohn, as cells with the unique ability to prime naïve antigen-specific T cells, it was realized that DC can exist in at least two distinctive states characterized by morphological, phenotypic and functional changes-this led to the description of DC maturation. It is now well appreciated that there are several subsets of DC in both lymphoid and non-lymphoid tissues of mammals, and these cells show remarkable functional specialization and specificity in their roles in tolerance and immunity. This review will focus on the specific characteristics of DC subsets and how their functional specialization may be regulated by distinctive gene expression programs and signaling responses in both steady-state and in the context of inflammation. In particular, we will highlight the common and distinctive genes and signaling pathways that are associated with the functional maturation of DC subsets. © 2014 The Authors.

Bacterial cell-cell communication in the host via RRNPP peptide-binding regulators

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David ePerez-Pascual

2016-05-01

Full Text Available Human microbiomes are composed of complex and dense bacterial consortia. In these environments, bacteria are able to react quickly to change by coordinating their gene expression at the population level via small signaling molecules. In Gram-positive bacteria, cell-cell communication is mostly mediated by peptides that are released into the extracellular environment. Cell-cell communication based on these peptides is especially widespread in the group Firmicutes, in which they regulate a wide array of biological processes, including functions related to host-microbe interactions. Among the different agents of communication, the RRNPP family of cytoplasmic transcriptional regulators, together with their cognate re-internalized signaling peptides, represents a group of emerging importance. RRNPP members that have been studied so far are found mainly in species of bacilli, streptococci, and enterococci. These bacteria are characterized as both human commensal and pathogenic, and share different niches in the human body with other microorganisms. The goal of this mini-review is to present the current state of research on the biological relevance of RRNPP mechanisms in the context of the host, highlighting their specific roles in commensalism or virulence.

Using riboswitches to regulate gene expression and define gene function in mycobacteria.

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Van Vlack, Erik R; Seeliger, Jessica C

2015-01-01

Mycobacteria include both environmental species and many pathogenic species such as Mycobacterium tuberculosis, an intracellular pathogen that is the causative agent of tuberculosis in humans. Inducible gene expression is a powerful tool for examining gene function and essentiality, both in in vitro culture and in host cell infections. The theophylline-inducible artificial riboswitch has recently emerged as an alternative to protein repressor-based systems. The riboswitch is translationally regulated and is combined with a mycobacterial promoter that provides transcriptional control. We here provide methods used by our laboratory to characterize the riboswitch response to theophylline in reporter strains, recombinant organisms containing riboswitch-regulated endogenous genes, and in host cell infections. These protocols should facilitate the application of both existing and novel artificial riboswitches to the exploration of gene function in mycobacteria. © 2015 Elsevier Inc. All rights reserved.

Regulated internalization of NMDA receptors drives PKD1-mediated suppression of the activity of residual cell-surface NMDA receptors.

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Fang, Xiao-Qian; Qiao, Haifa; Groveman, Bradley R; Feng, Shuang; Pflueger, Melissa; Xin, Wen-Kuan; Ali, Mohammad K; Lin, Shuang-Xiu; Xu, Jindong; Duclot, Florian; Kabbaj, Mohamed; Wang, Wei; Ding, Xin-Sheng; Santiago-Sim, Teresa; Jiang, Xing-Hong; Salter, Michael W; Yu, Xian-Min

2015-11-19

Constitutive and regulated internalization of cell surface proteins has been extensively investigated. The regulated internalization has been characterized as a principal mechanism for removing cell-surface receptors from the plasma membrane, and signaling to downstream targets of receptors. However, so far it is still not known whether the functional properties of remaining (non-internalized) receptor/channels may be regulated by internalization of the same class of receptor/channels. The N-methyl-D-aspartate receptor (NMDAR) is a principal subtype of glutamate-gated ion channel and plays key roles in neuronal plasticity and memory functions. NMDARs are well-known to undergo two types of regulated internalization - homologous and heterologous, which can be induced by high NMDA/glycine and DHPG, respectively. In the present work, we investigated effects of regulated NMDAR internalization on the activity of residual cell-surface NMDARs and neuronal functions. In electrophysiological experiments we discovered that the regulated internalization of NMDARs not only reduced the number of cell surface NMDARs but also caused an inhibition of the activity of remaining (non-internalized) surface NMDARs. In biochemical experiments we identified that this functional inhibition of remaining surface NMDARs was mediated by increased serine phosphorylation of surface NMDARs, resulting from the activation of protein kinase D1 (PKD1). Knockdown of PKD1 did not affect NMDAR internalization but prevented the phosphorylation and inhibition of remaining surface NMDARs and NMDAR-mediated synaptic functions. These data demonstrate a novel concept that regulated internalization of cell surface NMDARs not only reduces the number of NMDARs on the cell surface but also causes an inhibition of the activity of remaining surface NMDARs through intracellular signaling pathway(s). Furthermore, modulating the activity of remaining surface receptors may be an effective approach for treating receptor

A Simple Matter of Life and Death—The Trials of Postnatal Beta-Cell Mass Regulation

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Elena Tarabra

2012-01-01

Full Text Available Pancreatic beta-cells, which secrete the hormone insulin, are the key arbiters of glucose homeostasis. Defective beta-cell numbers and/or function underlie essentially all major forms of diabetes and must be restored if diabetes is to be cured. Thus, the identification of the molecular regulators of beta-cell mass and a better understanding of the processes of beta-cell differentiation and proliferation may provide further insight for the development of new therapeutic targets for diabetes. This review will focus on the principal hormones and nutrients, as well as downstream signalling pathways regulating beta-cell mass in the adult. Furthermore, we will also address more recently appreciated regulators of beta-cell mass, such as microRNAs.

Regulation of Germinal Center Reactions by B and T Cells

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Yeonseok Chung

2013-10-01

Full Text Available Break of B cell tolerance to self-antigens results in the development of autoantibodies and, thus, leads to autoimmunity. How B cell tolerance is maintained during active germinal center (GC reactions is yet to be fully understood. Recent advances revealed several subsets of T cells and B cells that can positively or negatively regulate GC B cell responses in vivo. IL-21-producing CXCR5+ CD4+ T cells comprise a distinct lineage of helper T cells—termed follicular helper T cells (TFH—that can provide help for the development of GC reactions where somatic hypermutation and affinity maturation take place. Although the function of TFH cells is beneficial in generating high affinity antibodies against infectious agents, aberrant activation of TFH cell or B cell to self-antigens results in autoimmunity. At least three subsets of immune cells have been proposed as regulatory cells that can limit such antibody-mediated autoimmunity, including follicular regulatory T cells (TFR, Qa-1 restricted CD8+ regulatory T cells (CD8+TREG, and regulatory B cells (BREG. In this review, we will discuss our current understanding of GC B cell regulation with specific emphasis on the newly identified immune cell subsets involved in this process.

Oxygen Tension Regulates Human Mesenchymal Stem Cell Paracrine Functions.

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Paquet, Joseph; Deschepper, Mickael; Moya, Adrien; Logeart-Avramoglou, Delphine; Boisson-Vidal, Catherine; Petite, Hervé

2015-07-01

: Mesenchymal stem cells (MSCs) have captured the attention and research endeavors of the scientific world because of their differentiation potential. However, there is accumulating evidence suggesting that the beneficial effects of MSCs are predominantly due to the multitude of bioactive mediators secreted by these cells. Because the paracrine potential of MSCs is closely related to their microenvironment, the present study investigated and characterized select aspects of the human MSC (hMSC) secretome and assessed its in vitro and in vivo bioactivity as a function of oxygen tension, specifically near anoxia (0.1% O2) and hypoxia (5% O2), conditions that reflect the environment to which MSCs are exposed during MSC-based therapies in vivo. In contrast to supernatant conditioned media (CM) obtained from hMSCs cultured at either 5% or 21% of O2, CM from hMSCs cultured under near anoxia exhibited significantly (p mesenchymal stem cell (hMSC) secretome and assessed its in vitro and in vivo biological bioactivity as a function of oxygen tension, specifically near anoxia (0.1% O2) and hypoxia (5% O2), conditions that reflect the environment to which MSCs are exposed during MSC-based therapies in vivo. The present study provided the first evidence of a shift of the hMSC cytokine signature induced by oxygen tension, particularly near anoxia (0.1% O2). Conditioned media obtained from hMSCs cultured under near anoxia exhibited significantly enhanced chemotactic and proangiogenic properties and a significant decrease in the inflammatory mediator content. These findings provide new evidence that elucidates aspects of great importance for the use of MSCs in regenerative medicine, could contribute to improving the efficacy of such therapies, and most importantly highlighted the interest in using conditioned media in therapeutic modalities. ©AlphaMed Press.

Complement Receptor 3 Has Negative Impact on Tumor Surveillance through Suppression of Natural Killer Cell Function

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Cheng-Fei Liu

2017-11-01

Full Text Available Complement receptor 3 (CR3 is expressed abundantly on natural killer (NK cells; however, whether it plays roles in NK cell-dependent tumor surveillance is largely unknown. Here, we show that CR3 is an important negative regulator of NK cell function, which has negative impact on tumor surveillance. Mice deficient in CR3 (CD11b−/− mice exhibited a more activated NK phenotype and had enhanced NK-dependent tumor killing. In a B16-luc melanoma-induced lung tumor growth and metastasis model, mice deficient in CR3 had reduced tumor growth and metastases, compared with WT mice. In addition, adaptive transfer of NK cells lacking CR3 (into NK-deficient mice mediated more efficient suppression of tumor growth and metastases, compared with the transfer of CR3 sufficient NK cells, suggesting that CR3 can impair tumor surveillance through suppression of NK cell function. In vitro analyses showed that engagement of CR3 with iC3b (classical CR3 ligand on NK cells negatively regulated NK cell activity and effector functions (i.e. direct tumor cell killing, antibody-dependent NK-mediated tumor killing. Cell signaling analyses showed that iC3b stimulation caused activation of Src homology 2 domain-containing inositol-5-phosphatase-1 (SHIP-1 and JNK, and suppression of ERK in NK cells, supporting that iC3b mediates negative regulation of NK cell function through its effects on SHIP-1, JNK, and ERK signal transduction pathways. Thus, our findings demonstrate a previously unknown role for CR3 in dysregulation of NK-dependent tumor surveillance and suggest that the iC3b/CR3 signaling is a critical negative regulator of NK cell function and may represent a new target for preserving NK cell function in cancer patients and improving NK cell-based therapy.

The cell cycle inhibitor p27Kip¹ controls self-renewal and pluripotency of human embryonic stem cells by regulating the cell cycle, Brachyury and Twist.

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Menchón, Cristina; Edel, Michael J; Izpisua Belmonte, Juan Carlos

2011-05-01

The continued turn over of human embryonic stem cells (hESC) while maintaining an undifferentiated state is dependent on the regulation of the cell cycle. Here we asked the question if a single cell cycle gene could regulate the self-renewal or pluripotency properties of hESC. We identified that the protein expression of the p27(Kip)¹ cell cycle inhibitor is low in hESC cells and increased with differentiation. By adopting a gain and loss of function strategy we forced or reduced its expression in undifferentiating conditions to define its functional role in self-renewal and pluripotency. Using undifferentiation conditions, overexpression of p27(Kip)¹ in hESC lead to a G₁phase arrest with an enlarged and flattened hESC morphology and consequent loss of self-renewal ability. Loss of p27(Kip)¹ caused an elongated/scatter cell-like phenotype involving up-regulation of Brachyury and Twist gene expression. We demonstrate the novel finding that p27(Kip)¹ protein occupies the Twist1 gene promoter and manipulation of p27(Kip)¹ by gain and loss of function is associated with Twist gene expression changes. These results define p27(Kip)¹ expression levels as critical for self-renewal and pluripotency in hESC and suggest a role for p27(Kip)¹ in controlling an epithelial to mesenchymal transition (EMT) in hESC.

Regulators of Tfh cell differentiation

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Gajendra Motiram Jogdand

2016-11-01

Full Text Available The follicular helper T (Tfh cells help is critical for activation of B cells, antibody class switching and germinal center formation. The Tfh cells are characterized by the expression of CXCR5, ICOS, PD-1, Bcl-6, and IL-21. They are involved in clearing infections and are adversely linked with autoimmune diseases and also have a role in viral replication as well as clearance. Tfh cells are generated from naïve CD4 T cells with sequential steps involving cytokine signaling (IL-21, IL-6, IL-12, activin A, migration and positioning in the germinal center by CXCR5, surface receptors (ICOS/ICOSL, SAP/SLAM as well as transcription factor (Bcl-6, c-Maf, STAT3 signaling and repressor miR155. On the other hand Tfh generation is negatively regulated at specific steps of Tfh generation by specific cytokine (IL-2, IL-7, surface receptor (PD-1, CTLA-4, transcription factors Blimp-1, STAT5, T-bet, KLF-2 signaling and repressor miR 146a. Interestingly, miR 17-92 and FOXO1 acts as a positive as well as a negative regulator of Tfh differentiation depending on the time of expression and disease specificity. Tfh cells are also generated from the conversion of other effector T cells as exemplified by Th1 cells converting into Tfh during viral infection. The mechanistic details of effector T cells conversion into Tfh are yet to be clear. To manipulate Tfh cells for therapeutic implication and or for effective vaccination strategies, it is important to know positive and negative regulators of Tfh generation. Hence, in this review we have highlighted and interlinked molecular signaling from cytokines, surface receptors, transcription factors, ubiquitin Ligase and miRNA as positive and negative regulators for Tfh differentiation.

Identification of microRNAs regulating the developmental pathways of bone marrow derived mast cells.

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Yang Xiang

Full Text Available MicroRNAs (miRNAs play important roles in leukocyte differentiation, although those utilised for specific programs and key functions remain incompletely characterised. As a global approach to gain insights into the potential regulatory role of miRNA in mast cell differentiation we characterised expression in BM cultures from the initiation of differentiation. In cultures enriched in differentiating mast cells we characterised miRNA expression and identified miRNA targeting the mRNA of putative factors involved in differentiation pathways and cellular identity. Detailed pathway analysis identified a unique miRNA network that is intimately linked to the mast cell differentiation program.We identified 86 unique miRNAs with expression patterns that were up- or down- regulated at 5-fold or more during bone marrow derived mast cells (BMMC development. By employing TargetScan and MeSH databases, we identified 524 transcripts involved in 30 canonical pathways as potentially regulated by these specific 86 miRNAs. Furthermore, by applying miRanda and IPA analyses, we predict that 7 specific miRNAs of this group are directly associated with the expression of c-Kit and FcεRIα and likewise, that 18 miRNAs promote expression of Mitf, GATA1 and c/EBPα three core transcription factors that direct mast cell differentiation. Furthermore, we have identified 11 miRNAs that may regulate the expression of STATs-3, -5a/b, GATA2 and GATA3 during differentiation, along with 13 miRNAs that target transcripts encoding Ndst2, mMCP4 and mMCP6 and thus may regulate biosynthesis of mast cell secretory mediators.This investigation characterises changes in miRNA expression in whole BM cultures during the differentiation of mast cells and predicts functional links between miRNAs and their target mRNAs for the regulation of development. This information provides an important resource for further investigations of the contributions of miRNAs to mast cell differentiation and

Cell Elasticity Determines Macrophage Function

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Patel, Naimish R.; Bole, Medhavi; Chen, Cheng; Hardin, Charles C.; Kho, Alvin T.; Mih, Justin; Deng, Linhong; Butler, James; Tschumperlin, Daniel; Fredberg, Jeffrey J.; Krishnan, Ramaswamy; Koziel, Henry

2012-01-01

Macrophages serve to maintain organ homeostasis in response to challenges from injury, inflammation, malignancy, particulate exposure, or infection. Until now, receptor ligation has been understood as being the central mechanism that regulates macrophage function. Using macrophages of different origins and species, we report that macrophage elasticity is a major determinant of innate macrophage function. Macrophage elasticity is modulated not only by classical biologic activators such as LPS and IFN-γ, but to an equal extent by substrate rigidity and substrate stretch. Macrophage elasticity is dependent upon actin polymerization and small rhoGTPase activation, but functional effects of elasticity are not predicted by examination of gene expression profiles alone. Taken together, these data demonstrate an unanticipated role for cell elasticity as a common pathway by which mechanical and biologic factors determine macrophage function. PMID:23028423

Cell elasticity determines macrophage function.

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Naimish R Patel

Full Text Available Macrophages serve to maintain organ homeostasis in response to challenges from injury, inflammation, malignancy, particulate exposure, or infection. Until now, receptor ligation has been understood as being the central mechanism that regulates macrophage function. Using macrophages of different origins and species, we report that macrophage elasticity is a major determinant of innate macrophage function. Macrophage elasticity is modulated not only by classical biologic activators such as LPS and IFN-γ, but to an equal extent by substrate rigidity and substrate stretch. Macrophage elasticity is dependent upon actin polymerization and small rhoGTPase activation, but functional effects of elasticity are not predicted by examination of gene expression profiles alone. Taken together, these data demonstrate an unanticipated role for cell elasticity as a common pathway by which mechanical and biologic factors determine macrophage function.

Regulation of Innate Lymphoid Cells by Aryl Hydrocarbon Receptor

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Li, Shiyang; Bostick, John W.; Zhou, Liang

2018-01-01

With striking similarity to their adaptive T helper cell counterparts, innate lymphoid cells (ILCs) represent an emerging family of cell types that express signature transcription factors, including T-bet+ Eomes+ natural killer cells, T-bet+ Eomes− group 1 ILCs, GATA3+ group 2 ILCs, RORγt+ group 3 ILCs, and newly identified Id3+ regulatory ILC. ILCs are abundantly present in barrier tissues of the host (e.g., the lung, gut, and skin) at the interface of host–environment interactions. Active research has been conducted to elucidate molecular mechanisms underlying the development and function of ILCs. The aryl hydrocarbon receptor (Ahr) is a ligand-dependent transcription factor, best known to mediate the effects of xenobiotic environmental toxins and endogenous microbial and dietary metabolites. Here, we review recent progresses regarding Ahr function in ILCs. We focus on the Ahr-mediated cross talk between ILCs and other immune/non-immune cells in host tissues especially in the gut. We discuss the molecular mechanisms of the action of Ahr expression and activity in regulation of ILCs in immunity and inflammation, and the interaction between Ahr and other pathways/transcription factors in ILC development and function with their implication in disease. PMID:29354125

The lupus susceptibility gene Pbx1 regulates the balance between follicular helper T cell and regulatory T cell differentiation

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Choi, Seung-Chul; Hutchinson, Tarun E.; Titov, Anton A.; Seay, Howard R.; Li, Shiwu; Brusko, Todd M.; Croker, Byron P.; Salek-Ardakani, Shahram; Morel, Laurence

2016-01-01

Pbx1 controls chromatin accessibility to a large number of genes and is entirely conserved between mice and humans. The Pbx1-d dominant negative isoform is more frequent in the CD4+ T cells from lupus patients than from healthy controls. Pbx1-d is associated with the production of autoreactive T cells in mice carrying the Sle1a1 lupus susceptibility locus. Transgenic expression of Pbx1-d in CD4+ T cells reproduced the phenotypes of Sle1a1 mice, with increased inflammatory functions of CD4+ T cells and impaired regulatory T cell homeostasis. Pbx1-d Tg also expanded the number of follicular helper T cells in a cell-intrinsic and antigen-specific manner that was enhanced in recall responses, and resulted in TH1-biased antibodies. Moreover, Pbx1-d Tg CD4+ T cells upregulated the expression of miR-10a, miR-21 and miR-155, which have been implicated in Treg and TFH cell homeostasis. Our results suggest that Pbx1-d impacts lupus development by regulating effector T cell differentiation and promoting TFH cells at the expense of Treg cells. In addition, our results identify Pbx1 as a novel regulator of CD4+ T cell effector function. PMID:27296664

Dynamic balance between master transcription factors determines the fates and functions of CD4 T cell and innate lymphoid cell subsets

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2017-01-01

CD4 T cells, including T regulatory cells (Treg cells) and effector T helper cells (Th cells), and recently identified innate lymphoid cells (ILCs) play important roles in host defense and inflammation. Both CD4 T cells and ILCs can be classified into distinct lineages based on their functions and the expression of lineage-specific genes, including those encoding effector cytokines, cell surface markers, and key transcription factors. It was first recognized that each lineage expresses a specific master transcription factor and the expression of these factors is mutually exclusive because of cross-regulation among these factors. However, recent studies indicate that the master regulators are often coexpressed. Furthermore, the expression of master regulators can be dynamic and quantitative. In this review, we will first discuss similarities and differences between the development and functions of CD4 T cell and ILC subsets and then summarize recent literature on quantitative, dynamic, and cell type–specific balance between the master transcription factors in determining heterogeneity and plasticity of these subsets. PMID:28630089

Progranulin regulates lysosomal function and biogenesis through acidification of lysosomes.

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Tanaka, Yoshinori; Suzuki, Genjiro; Matsuwaki, Takashi; Hosokawa, Masato; Serrano, Geidy; Beach, Thomas G; Yamanouchi, Keitaro; Hasegawa, Masato; Nishihara, Masugi

2017-03-01

Progranulin (PGRN) haploinsufficiency resulting from loss-of-function mutations in the PGRN gene causes frontotemporal lobar degeneration accompanied by TDP-43 accumulation, and patients with homozygous mutations in the PGRN gene present with neuronal ceroid lipofuscinosis. Although it remains unknown why PGRN deficiency causes neurodegenerative diseases, there is increasing evidence that PGRN is implicated in lysosomal functions. Here, we show PGRN is a secretory lysosomal protein that regulates lysosomal function and biogenesis by controlling the acidification of lysosomes. PGRN gene expression and protein levels increased concomitantly with the increase of lysosomal biogenesis induced by lysosome alkalizers or serum starvation. Down-regulation or insufficiency of PGRN led to the increased lysosomal gene expression and protein levels, while PGRN overexpression led to the decreased lysosomal gene expression and protein levels. In particular, the level of mature cathepsin D (CTSDmat) dramatically changed depending upon PGRN levels. The acidification of lysosomes was facilitated in cells transfected with PGRN. Then, this caused degradation of CTSDmat by cathepsin B. Secreted PGRN is incorporated into cells via sortilin or cation-independent mannose 6-phosphate receptor, and facilitated the acidification of lysosomes and degradation of CTSDmat. Moreover, the change of PGRN levels led to a cell-type-specific increase of insoluble TDP-43. In the brain tissue of FTLD-TDP patients with PGRN deficiency, CTSD and phosphorylated TDP-43 accumulated in neurons. Our study provides new insights into the physiological function of PGRN and the role of PGRN insufficiency in the pathogenesis of neurodegenerative diseases. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

IL-15 regulates homeostasis and terminal maturation of NKT cells1

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Gordy, Laura E.; Bezbradica, Jelena S.; Flyak, Andrew I.; Spencer, Charles T.; Dunkle, Alexis; Sun, Jingchun; Stanic, Aleksandar K.; Boothby, Mark R.; He, You-Wen; Zhao, Zhongming; Van Kaer, Luc; Joyce, Sebastian

2011-01-01

Semi-invariant natural killer T (NKT) cells are thymus-derived innate lymphocytes that modulate microbial and tumour immunity as well as autoimmune diseases. These immunoregulatory properties of NKT cells are acquired during their development. Much has been learnt regarding the molecular and cellular cues that promote NKT cell development, yet how these cells are maintained in the thymus and the periphery and how they acquire functional competence are incompletely understood. We found that IL-15 induced several Bcl-2 family survival factors in thymic and splenic NKT cells in vitro. Yet, IL15-mediated thymic and peripheral NKT cell survival critically depended on Bcl-xL expression. Additionally, IL-15 regulated thymic developmental stage 2 (ST2) to ST3 lineage progression and terminal NKT cell differentiation. Global gene expression analyses and validation revealed that IL-15 regulated Tbx21 (T-bet) expression in thymic NKT cells. The loss of IL15 also resulted in poor expression of key effector molecules such as IFN-γ, granzyme A and C as well as several NK cell receptors in NKT cells. Taken together, our findings reveal a critical role for IL-15 in NKT cell survival, which is mediated by Bcl-xL, and effector differentiation, which is consistent with a role of T-bet in regulating terminal maturation. PMID:22084435

MTSS1 is epigenetically regulated in glioma cells and inhibits glioma cell motility

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Daniel Luxen

2017-02-01

Full Text Available Epigenetic silencing by DNA methylation in brain tumors has been reported for many genes, however, their function on pathogenesis needs to be evaluated. We investigated the MTSS1 gene, identified as hypermethylated by differential methylation hybridization (DMH. Fifty-nine glioma tissue samples and seven glioma cell lines were examined for hypermethylation of the MTSS1 promotor, MTSS1 expression levels and gene dosage. GBM cell lines were treated with demethylating agents and interrogated for functional consequences of MTSS1 expression after transient transfection. Hypermethylation was significantly associated with IDH1/2 mutation. Comparative SNP analysis indicates higher incidence of loss of heterozygosity of MTSS1 in anaplastic astrocytomas and secondary glioblastomas as well as hypermethylation of the remaining allele. Reversal of promoter hypermethylation results in an increased MTSS1 expression. Cell motility was significantly inhibited by MTSS1 overexpression without influencing cell growth or apoptosis. Immunofluorescence analysis of MTSS1 in human astrocytes indicates co-localization with actin filaments. MTSS1 is down-regulated by DNA methylation in glioblastoma cell lines and is part of the G-CIMP phenotype in primary glioma tissues. Our data on normal astrocytes suggest a function of MTSS1 at focal contact structures with an impact on migratory capacity but no influence on apoptosis or cellular proliferation.

Regulation of Mitochondrial Function and Cellular Energy Metabolism by Protein Kinase C-λ/ι: A Novel Mode of Balancing Pluripotency

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Mahato, Biraj; Home, Pratik; Rajendran, Ganeshkumar; Paul, Arindam; Saha, Biswarup; Ganguly, Avishek; Ray, Soma; Roy, Nairita; Swerdlow, Russell H.; Paul, Soumen

2014-01-01

Pluripotent stem cells (PSCs) contain functionally immature mitochondria and rely upon high rates of glycolysis for their energy requirements. Thus, altered mitochondrial function and promotion of aerobic glycolysis is key to maintain and induce pluripotency. However, signaling mechanisms that regulate mitochondrial function and reprogram metabolic preferences in self-renewing vs. differentiated PSC populations are poorly understood. Here, using murine embryonic stem cells (ESCs) as a model system, we demonstrate that atypical protein kinase C isoform, PKC lambda/iota (PKCλ/ι), is a key regulator of mitochondrial function in ESCs. Depletion of PKCλ/ι in ESCs maintains their pluripotent state as evident from germline offsprings. Interestingly, loss of PKCλ/ι in ESCs leads to impairment in mitochondrial maturation, organization and a metabolic shift toward glycolysis under differentiating condition. Our mechanistic analyses indicate that a PKCλ/ι-HIF1α-PGC1α axis regulates mitochondrial respiration and balances pluripotency in ESCs. We propose that PKCλ/ι could be a crucial regulator of mitochondrial function and energy metabolism in stem cells and other cellular contexts. PMID:25142417

Autoimmune Regulator (AIRE) Is Expressed in Spermatogenic Cells, and It Altered the Expression of Several Nucleic-Acid-Binding and Cytoskeletal Proteins in Germ Cell 1 Spermatogonial (GC1-spg) Cells.

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Radhakrishnan, Karthika; Bhagya, Kongattu P; Kumar, Anil Tr; Devi, Anandavalli N; Sengottaiyan, Jeeva; Kumar, Pradeep G

2016-08-01

Autoimmune regulator (AIRE) is a gene associated with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED). AIRE is expressed heavily in the thymic epithelial cells and is involved in maintaining self-tolerance through regulating the expression of tissue-specific antigens. The testes are the most predominant extrathymic location where a heavy expression of AIRE is reported. Homozygous Aire-deficient male mice were infertile, possibly due to impaired spermatogenesis, deregulated germ cell apoptosis, or autoimmunity. We report that AIRE is expressed in the testes of neonatal, adolescent, and adult mice. AIRE expression was detected in glial cell derived neurotrophic factor receptor alpha (GFRα)(+) (spermatogonia), GFRα(-)/synaptonemal complex protein (SCP3)(+) (meiotic), and GFRα(-)/Phosphoglycerate kinase 2 (PGK2)(+) (postmeiotic) germ cells in mouse testes. GC1-spg, a germ-cell-derived cell line, did not express AIRE. Retinoic acid induced AIRE expression in GC1-spg cells. Ectopic expression of AIRE in GC1-spg cells using label-free LC-MS/MS identified a total of 371 proteins that were differentially expressed. 100 proteins were up-regulated, and 271 proteins were down-regulated. Data are available via ProteomeXchange with identifier PXD002511. Functional analysis of the differentially expressed proteins showed increased levels of various nucleic-acid-binding proteins and transcription factors and a decreased level of various cytoskeletal and structural proteins in the AIRE overexpressing cells as compared with the empty vector-transfected controls. The transcripts of a select set of the up-regulated proteins were also elevated. However, there was no corresponding decrease in the mRNA levels of the down-regulated set of proteins. Molecular function network analysis indicated that AIRE influenced gene expression in GC1-spg cells by acting at multiple levels, including transcription, translation, RNA processing, protein transport, protein

Reciprocal expression of Bmi1 and Mel-18 is associated with functioning of primitive hematopoietic cells.

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Kajiume, Teruyuki; Ohno, Norioki; Sera, Yasuhiko; Kawahara, Yumi; Yuge, Louis; Kobayashi, Masao

2009-07-01

The Polycomb-group (PcG) genes regulate global gene expression in many biological processes, including hematopoiesis, by manipulating specific target genes. It is known that various PcG genes regulate self-renewal of hematopoietic stem cells (HSCs). Here we have shown that the reciprocal expression of PcG proteins regulates self-renewal and differentiation of HSCs. We used murine and human bone marrow cells and evaluated the reciprocal expression of PcG proteins on the basis of their respective intranuclear distributions. PcG-gene expression in HSCs was knocked down by small interfering RNAs. The function of each gene in HSCs was analyzed in vitro and in vivo. Cells were either Bmi1-positive or Mel-18-positive. The Bmi1-positive cells contained very little amounts of Mel-18 and vice versa. The bmi1-knockdown marrow cells did not show HSC function, while the mel-18-knockdown marrow cells showed increased stem cell function. Results of the analysis on human cells were similar to those observed in case of murine cells. In a clinical investigation, transplantation using sources with a low Bmi1 to Mel-18 ratio was associated with early hematopoietic recovery. Reciprocal expression of Bmi1 and Mel-18 regulated HSC function. Here, we observed that expression of the PcG genes-bmi1 and mel-18-is correlated with self-renewal and differentiation of HSCs. Thus, it was suggested that the balance between Bmi1 and Mel-18 regulates self-renewal of HSCs.

Churchill regulates cell movement and mesoderm specification by repressing Nodal signaling

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Mentzer Laura

2007-11-01

Full Text Available Abstract Background Cell movements are essential to the determination of cell fates during development. The zinc-finger transcription factor, Churchill (ChCh has been proposed to regulate cell fate by regulating cell movements during gastrulation in the chick. However, the mechanism of action of ChCh is not understood. Results We demonstrate that ChCh acts to repress the response to Nodal-related signals in zebrafish. When ChCh function is abrogated the expression of mesodermal markers is enhanced while ectodermal markers are expressed at decreased levels. In cell transplant assays, we observed that ChCh-deficient cells are more motile than wild-type cells. When placed in wild-type hosts, ChCh-deficient cells often leave the epiblast, migrate to the germ ring and are later found in mesodermal structures. We demonstrate that both movement of ChCh-compromised cells to the germ ring and acquisition of mesodermal character depend on the ability of the donor cells to respond to Nodal signals. Blocking Nodal signaling in the donor cells at the levels of Oep, Alk receptors or Fast1 inhibited migration to the germ ring and mesodermal fate change in the donor cells. We also detect additional unusual movements of transplanted ChCh-deficient cells which suggests that movement and acquisition of mesodermal character can be uncoupled. Finally, we demonstrate that ChCh is required to limit the transcriptional response to Nodal. Conclusion These data establish a broad role for ChCh in regulating both cell movement and Nodal signaling during early zebrafish development. We show that chch is required to limit mesodermal gene expression, inhibit Nodal-dependant movement of presumptive ectodermal cells and repress the transcriptional response to Nodal signaling. These findings reveal a dynamic role for chch in regulating cell movement and fate during early development.

Role of Estrogen in Thyroid Function and Growth Regulation

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Ana Paula Santin

2011-01-01

Full Text Available Thyroid diseases are more prevalent in women, particularly between puberty and menopause. It is wellknown that estrogen (E has indirect effects on the thyroid economy. Direct effects of this steroid hormone on thyroid cells have been described more recently; so, the aim of the present paper was to review the evidences of these effects on thyroid function and growth regulation, and its mechanisms. The expression and ratios of the two E receptors, α and β, that mediate the genomic effects of E on normal and abnormal thyroid tissue were also reviewed, as well as nongenomic, distinct molecular pathways. Several evidences support the hypothesis that E has a direct role in thyroid follicular cells; understanding its influence on the growth and function of the thyroid in normal and abnormal conditions can potentially provide new targets for the treatment of thyroid diseases.

Cell shape regulates global histone acetylation in human mammaryepithelial cells

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Le Beyec, Johanne; Xu, Ren; Lee, Sun-Young; Nelson, Celeste M.; Rizki, Aylin; Alcaraz, Jordi; Bissell, Mina J.

2007-02-28

Extracellular matrix (ECM) regulates cell morphology and gene expression in vivo; these relationships are maintained in three-dimensional (3D) cultures of mammary epithelial cells. In the presence of laminin-rich ECM (lrECM), mammary epithelial cells round up and undergo global histone deacetylation, a process critical for their functional differentiation. However, it remains unclear whether lrECM-dependent cell rounding and global histone deacetylation are indeed part of a common physical-biochemical pathway. Using 3D cultures as well as nonadhesive and micropatterned substrata, here we showed that the cell 'rounding' caused by lrECM was sufficient to induce deacetylation of histones H3 and H4 in the absence of biochemical cues. Microarray and confocal analysis demonstrated that this deacetylation in 3D culture is associated with a global increase in chromatin condensation and a reduction in gene expression. Whereas cells cultured on plastic substrata formed prominent stress fibers, cells grown in 3D lrECM or on micropatterns lacked these structures. Disruption of the actin cytoskeleton with cytochalasin D phenocopied the lrECM-induced cell rounding and histone deacetylation. These results reveal a novel link between ECM-controlled cell shape and chromatin structure, and suggest that this link is mediated by changes in the actin cytoskeleton.

NK Cell Subtypes as Regulators of Autoimmune Liver Disease

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Guohui Jiao

2016-01-01

Full Text Available As major components of innate immunity, NK cells not only exert cell-mediated cytotoxicity to destroy tumors or infected cells, but also act to regulate the functions of other cells in the immune system by secreting cytokines and chemokines. Thus, NK cells provide surveillance in the early defense against viruses, intracellular bacteria, and cancer cells. However, the effecter function of NK cells must be exquisitely controlled to prevent inadvertent attack against normal “self” cells. In an organ such as the liver, where the distinction between immunotolerance and immune defense against routinely processed pathogens is critical, the plethora of NK cells has a unique role in the maintenance of homeostasis. Once self-tolerance is broken, autoimmune liver disease resulted. NK cells act as a “two-edged weapon” and even play opposite roles with both regulatory and inducer activities in the hepatic environment. That is, NK cells act not only to produce inflammatory cytokines and chemokines, but also to alter the proliferation and activation of associated lymphocytes. However, the precise regulatory mechanisms at work in autoimmune liver diseases remain to be identified. In this review, we focus on recent research with NK cells and their potential role in the development of autoimmune liver disease.

JMJD2A attenuation affects cell cycle and tumourigenic inflammatory gene regulation in lipopolysaccharide stimulated neuroectodermal stem cells

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Das, Amitabh, E-mail: amitabhdas.kn@gmail.com [Department of Bionanotechnology, Hanyang University, Seoul 133-791 (Korea, Republic of); Chai, Jin Choul, E-mail: jincchai@gmail.com [Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of); Jung, Kyoung Hwa, E-mail: khjung2@gmail.com [Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of); Das, Nando Dulal, E-mail: nando.hu@gmail.com [Clinical Research Centre, Inha University School of Medicine, Incheon 400-711 (Korea, Republic of); Kang, Sung Chul, E-mail: gujiju11@gmail.com [Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of); Lee, Young Seek, E-mail: yslee@hanyang.ac.kr [Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of); Seo, Hyemyung, E-mail: hseo@hanyang.ac.kr [Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of); Chai, Young Gyu, E-mail: ygchai@hanyang.ac.kr [Department of Bionanotechnology, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of)

2014-11-01

JMJD2A is a lysine trimethyl-specific histone demethylase that is highly expressed in a variety of tumours. The role of JMJD2A in tumour progression remains unclear. The objectives of this study were to identify JMJD2A-regulated genes and understand the function of JMJD2A in p53-null neuroectodermal stem cells (p53{sup −/−} NE-4Cs). We determined the effect of LPS as a model of inflammation in p53{sup −/−} NE-4Cs and investigated whether the epigenetic modifier JMJD2A alter the expression of tumourigenic inflammatory genes. Global gene expression was measured in JMJD2A knockdown (kd) p53{sup −/−} NE-4Cs and in LPS-stimulated JMJD2A-kd p53{sup −/−} NE-4C cells. JMJD2A attenuation significantly down-regulated genes were Cdca2, Ccnd2, Ccnd1, Crebbp, IL6rα, and Stat3 related with cell cycle, proliferation, and inflammatory-disease responses. Importantly, some tumour-suppressor genes including Dapk3, Timp2 and TFPI were significantly up-regulated but were not affected by silencing of the JMJD2B. Furthermore, we confirmed the attenuation of JMJD2A also down-regulated Cdca2, Ccnd2, Crebbp, and Rest in primary NSCs isolated from the forebrains of E15 embryos of C57/BL6J mice with effective p53 inhibitor pifithrin-α (PFT-α). Transcription factor (TF) motif analysis revealed known binding patterns for CDC5, MYC, and CREB, as well as three novel motifs in JMJD2A-regulated genes. IPA established molecular networks. The molecular network signatures and functional gene-expression profiling data from this study warrants further investigation as an effective therapeutic target, and studies to elucidate the molecular mechanism of JMJD2A-kd-dependent effects in neuroectodermal stem cells should be performed. - Highlights: • Significant up-regulation of epigenetic modifier JMJD2A mRNA upon LPS treatment. • Inhibition of JMJD2A attenuated key inflammatory and tumourigenic genes. • Establishing IPA based functional genomics in JMJD2A-attenuated p53{sup �

Regulation of cell cycle progression by cell-cell and cell-matrix forces

NARCIS (Netherlands)

Uroz, Marina; Wistorf, Sabrina; Serra-Picamal, Xavier; Conte, Vito; Sales-Pardo, Marta; Roca-Cusachs, Pere; Guimerà, Roger; Trepat, Xavier

2018-01-01

It has long been proposed that the cell cycle is regulated by physical forces at the cell-cell and cell-extracellular matrix (ECM) interfaces 1-12 . However, the evolution of these forces during the cycle has never been measured in a tissue, and whether this evolution affects cell cycle progression

Vinculin contributes to Cell Invasion by Regulating Contractile Activation

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Mierke, Claudia Tanja

2008-07-01

Vinculin is a component of the focal adhesion complex and is described as a mechano-coupling protein connecting the integrin receptor and the actin cytoskeleton. Vinculin knock-out (k.o.) cells (vin-/-) displayed increased migration on a 2-D collagen- or fibronectin-coated substrate compared to wildtype cells, but the role of vinculin in cell migration through a 3-D connective tissue is unknown. We determined the invasiveness of established tumor cell lines using a 3-D collagen invasion assay. Gene expression analysis of 4 invasive and 4 non-invasive tumor cell lines revealed that vinculin expression was significantly increased in invasive tumor cell lines. To analyze the mechanisms by which vinculin increased cell invasion in a 3-D gel, we studied mouse embryonic fibroblasts wildtype and vin-/- cells. Wildtype cells were 3-fold more invasive compared vin-/- cells. We hypothesized that the ability to generate sufficient traction forces is a prerequisite for tumor cell migration in a 3-D connective tissue matrix. Using traction microscopy, we found that wildtype exerted 3-fold higher tractions on fibronectin-coated polyacrylamide gels compared to vin-/- cells. These results show that vinculin controls two fundamental functions that lead to opposite effects on cell migration in a 2-D vs. a 3-D environment: On the one hand, vinculin stabilizes the focal adhesions (mechano-coupling function) and thereby reduces motility in 2-D. On the other hand, vinculin is also a potent activator of traction generation (mechano-regulating function) that is important for cell invasion in a 3-D environment.

Volume regulation and shape bifurcation in the cell nucleus.

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Kim, Dong-Hwee; Li, Bo; Si, Fangwei; Phillip, Jude M; Wirtz, Denis; Sun, Sean X

2015-09-15

Alterations in nuclear morphology are closely associated with essential cell functions, such as cell motility and polarization, and correlate with a wide range of human diseases, including cancer, muscular dystrophy, dilated cardiomyopathy and progeria. However, the mechanics and forces that shape the nucleus are not well understood. Here, we demonstrate that when an adherent cell is detached from its substratum, the nucleus undergoes a large volumetric reduction accompanied by a morphological transition from an almost smooth to a heavily folded surface. We develop a mathematical model that systematically analyzes the evolution of nuclear shape and volume. The analysis suggests that the pressure difference across the nuclear envelope, which is influenced by changes in cell volume and regulated by microtubules and actin filaments, is a major factor determining nuclear morphology. Our results show that physical and chemical properties of the extracellular microenvironment directly influence nuclear morphology and suggest that there is a direct link between the environment and gene regulation. © 2015. Published by The Company of Biologists Ltd.

Glucagon Couples Hepatic Amino Acid Catabolism to mTOR-Dependent Regulation of α-Cell Mass

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Mark J. Solloway

2015-07-01

Full Text Available Understanding the regulation of islet cell mass has important implications for the discovery of regenerative therapies for diabetes. The liver plays a central role in metabolism and the regulation of endocrine cell number, but liver-derived factors that regulate α-cell and β-cell mass remain unidentified. We propose a nutrient-sensing circuit between liver and pancreas in which glucagon-dependent control of hepatic amino acid metabolism regulates α-cell mass. We found that glucagon receptor inhibition reduced hepatic amino acid catabolism, increased serum amino acids, and induced α-cell proliferation in an mTOR-dependent manner. In addition, mTOR inhibition blocked amino-acid-dependent α-cell replication ex vivo and enabled conversion of α-cells into β-like cells in vivo. Serum amino acids and α-cell proliferation were increased in neonatal mice but fell throughout postnatal development in a glucagon-dependent manner. These data reveal that amino acids act as sensors of glucagon signaling and can function as growth factors that increase α-cell proliferation.

Lysosomal Regulation of mTORC1 by Amino Acids in Mammalian Cells

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Yao Yao

2017-07-01

Full Text Available The mechanistic target of rapamycin complex 1 (mTORC1 is a master regulator of cell growth in eukaryotic cells. The active mTORC1 promotes cellular anabolic processes including protein, pyrimidine, and lipid biosynthesis, and inhibits catabolic processes such as autophagy. Consistent with its growth-promoting functions, hyper-activation of mTORC1 signaling is one of the important pathomechanisms underlying major human health problems including diabetes, neurodegenerative disorders, and cancer. The mTORC1 receives multiple upstream signals such as an abundance of amino acids and growth factors, thus it regulates a wide range of downstream events relevant to cell growth and proliferation control. The regulation of mTORC1 by amino acids is a fast-evolving field with its detailed mechanisms currently being revealed as the precise picture emerges. In this review, we summarize recent progress with respect to biochemical and biological findings in the regulation of mTORC1 signaling on the lysosomal membrane by amino acids.

Drosophila Glypicans Regulate Follicle Stem Cell Maintenance and Niche Competition.

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Su, Tsu-Yi; Nakato, Eriko; Choi, Pui Yee; Nakato, Hiroshi

2018-04-09

Adult stem cells reside in specialized microenvironments, called niches, which provide signals for stem cells to maintain their undifferentiated and self-renewing state. To maintain stem cell quality, several types of stem cells are known to be regularly replaced by progenitor cells through niche competition. However, the cellular and molecular bases for stem cell competition for niche occupancy are largely unknown. Here, we show that two Drosophila members of the glypican family of heparan sulfate proteoglycans (HSPGs), Dally and Dally-like (Dlp), differentially regulate follicle stem cell (FSC) maintenance and FSC competitiveness for niche occupancy. Lineage analyses of glypican mutant FSC clones showed that dally is essential for normal FSC maintenance. In contrast, dlp is a hyper-competitive mutation: dlp mutant FSC progenitors often eventually occupy the entire epithelial sheet. RNAi knockdown experiments showed that Dally and Dlp play both partially redundant and distinct roles in regulating Jak/Stat, Wg and Hh signaling in FSCs. The Drosophila FSC system offers a powerful genetic model to study the mechanisms by which HSPGs exert specific functions in stem cell replacement and competition. Copyright © 2018, Genetics.

Identification of Novel Ovarian Cancer Oncogenes that Function by Regulating Exosome Function

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2017-09-01

Novel Ovarian Cancer Oncogenes that Function by Regulating Exosome Function September 2017 x 1Sep2016...31Aug2017 Email: mbirrer@partners.org 6 Identification of Novel Ovarian Cancer Oncogenes that Function by Regulating Exosome Function xx

Interleukin 20 regulates dendritic cell migration and expression of co-stimulatory molecules

DEFF Research Database (Denmark)

Bech, Rikke; Jalilian, Babak; Agger, Ralf

2016-01-01

BACKGROUND: Psoriasis is an inflammatory disease characterized by leukocyte skin infiltration. Interestingly, recent works suggest that the migration of dendritic cells (DCs) is abnormal in psoriatic skin. DCs have significant role in regulating the function of T lymphocytes, at least in part...... influenced by the local environment of cytokines. In psoriatic skin lesions the expression of IL-20 is highly up-regulated. It is unclear if this cytokine has any influence on DCs. METHODS: Here, we investigated the influence of IL-20 in monocyte-derived dendritic cell (MDDCs) in vitro. This work addressed...

Evidence for paracrine/autocrine regulation of GLP-1-producing cells

DEFF Research Database (Denmark)

Kappe, Camilla; Zhang, Qimin; Holst, Jens Juul

2013-01-01

Glucagon-like peptide-1 (GLP-1), secreted from gut L cells upon nutrient intake, forms the basis for novel drugs against type 2 diabetes (T2D). Secretion of GLP-1 has been suggested to be impaired in T2D and in conditions associated with hyperlipidemia and insulin resistance. Further, recent...... studies support lipotoxicity of GLP-1-producing cells in vitro. However, little is known about the regulation of L-cell viability/function, the effects of insulin signaling, or the potential effects of stable GLP-1 analogs and dipeptidyl peptidase-4 (DPP-4) inhibitors. We determined effects of insulin...... as well as possible autocrine action of GLP-1 on viability/apoptosis of GLP-1-secreting cells in the presence/absence of palmitate, while also assessing direct effects on function. The studies were performed using the GLP-1-secreting cell line GLUTag, and palmitate was used to simulate hyperlipidemia. Our...

Semaphorin7A and its receptors: pleiotropic regulators of immune cell function, bone homeostasis, and neural development.

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Jongbloets, Bart C; Ramakers, Geert M J; Pasterkamp, R Jeroen

2013-03-01

Semaphorins form a large, evolutionary conserved family of cellular guidance signals. The semaphorin family contains several secreted and transmembrane proteins, but only one GPI-anchored member, Semaphorin7A (Sema7A). Although originally identified in immune cells, as CDw108, Sema7A displays widespread expression outside the immune system. It is therefore not surprising that accumulating evidence supports roles for this protein in a wide variety of biological processes in different organ systems and in disease. Well-characterized biological effects of Sema7A include those during bone and immune cell regulation, neuron migration and neurite growth. These effects are mediated by two receptors, plexinC1 and integrins. However, most of what is known today about Sema7A signaling concerns Sema7A-integrin interactions. Here, we review our current knowledge of Sema7A function and signaling in different organ systems, highlighting commonalities between the cellular effects and signaling pathways activated by Sema7A in different cell types. Furthermore, we discuss a potential role for Sema7A in disease and provide directions for further research. Copyright © 2013 Elsevier Ltd. All rights reserved.

Tetraspanin CD9 regulates cell contraction and actin arrangement via RhoA in human vascular smooth muscle cells.

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Michael J Herr

Full Text Available The most prevalent cardiovascular diseases arise from alterations in vascular smooth muscle cell (VSMC morphology and function. Tetraspanin CD9 has been previously implicated in regulating vascular pathologies; however, insight into how CD9 may regulate adverse VSMC phenotypes has not been provided. We utilized a human model of aortic smooth muscle cells to understand the consequences of CD9 deficiency on VSMC phenotypes. Upon knocking down CD9, the cells developed an abnormally small and rounded morphology. We determined that this morphological change was due to a lack of typical parallel actin arrangement. We also found similar total RhoA but decreased GTP-bound (active RhoA levels in CD9 deficient cells. As a result, cells lacking a full complement of CD9 were less contractile than their control treated counterparts. Upon restoration of RhoA activity in the CD9 deficient cells, the phenotype was reversed and cell contraction was restored. Conversely, inhibition of RhoA activity in the control cells mimicked the CD9-deficient cell phenotype. Thus, alteration in CD9 expression was sufficient to profoundly disrupt cellular actin arrangement and endogenous cell contraction by interfering with RhoA signaling. This study provides insight into how CD9 may regulate previously described vascular smooth muscle cell pathophysiology.

Cell cycle regulation in human embryonic stem cells: links to adaptation to cell culture.

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Barta, Tomas; Dolezalova, Dasa; Holubcova, Zuzana; Hampl, Ales

2013-03-01

Cell cycle represents not only a tightly orchestrated mechanism of cell replication and cell division but it also plays an important role in regulation of cell fate decision. Particularly in the context of pluripotent stem cells or multipotent progenitor cells, regulation of cell fate decision is of paramount importance. It has been shown that human embryonic stem cells (hESCs) show unique cell cycle characteristics, such as short doubling time due to abbreviated G1 phase; these properties change with the onset of differentiation. This review summarizes the current understanding of cell cycle regulation in hESCs. We discuss cell cycle properties as well as regulatory machinery governing cell cycle progression of undifferentiated hESCs. Additionally, we provide evidence that long-term culture of hESCs is accompanied by changes in cell cycle properties as well as configuration of several cell cycle regulatory molecules.

Role and regulation of apoptotic cell death in the kidney. Y2K update.

Science.gov (United States)

Ortiz, A; Lorz, C; Catalan, M P; Justo, P; Egido, J

2000-08-01

Apoptosis is an active form of cell death that, in balance with mitosis, regulates cell number. Cell number abnormalities are a frequent feature of renal disease. We now review current concepts on the molecular regulation of apoptotic cell death, including the influence of survival and lethal factors from the extracellular microenvironment as well as the role of intracellular regulators of apoptosis, such as death receptors, proapoptotic and antiapoptotic bcl2-related proteins, the mitochondria and caspases. In addition the role of apoptosis in the genesis, persistence and progression and remodeling and resolution of renal injury is discussed. Information on the expression and function of apoptosis regulatory proteins in specific renal syndromes is summarized. Finally, future perspectives in research and clinical intervention are discussed.

Somite-Derived Retinoic Acid Regulates Zebrafish Hematopoietic Stem Cell Formation.

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Laura M Pillay

Full Text Available Hematopoietic stem cells (HSCs are multipotent progenitors that generate all vertebrate adult blood lineages. Recent analyses have highlighted the importance of somite-derived signaling factors in regulating HSC specification and emergence from dorsal aorta hemogenic endothelium. However, these factors remain largely uncharacterized. We provide evidence that the vitamin A derivative retinoic acid (RA functions as an essential regulator of zebrafish HSC formation. Temporal analyses indicate that RA is required for HSC gene expression prior to dorsal aorta formation, at a time when the predominant RA synthesis enzyme, aldh1a2, is strongly expressed within the paraxial mesoderm and somites. Previous research implicated the Cxcl12 chemokine and Notch signaling pathways in HSC formation. Consequently, to understand how RA regulates HSC gene expression, we surveyed the expression of components of these pathways in RA-depleted zebrafish embryos. During somitogenesis, RA-depleted embryos exhibit altered expression of jam1a and jam2a, which potentiate Notch signaling within nascent endothelial cells. RA-depleted embryos also exhibit a severe reduction in the expression of cxcr4a, the predominant Cxcl12b receptor. Furthermore, pharmacological inhibitors of RA synthesis and Cxcr4 signaling act in concert to reduce HSC formation. Our analyses demonstrate that somite-derived RA functions to regulate components of the Notch and Cxcl12 chemokine signaling pathways during HSC formation.

Functions of Heterogeneous Nuclear Ribonucleoproteins in Stem Cell Potency and Differentiation

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Qishan Chen

2013-01-01

Full Text Available Stem cells possess huge importance in developmental biology, disease modelling, cell replacement therapy, and tissue engineering in regenerative medicine because they have the remarkable potential for self-renewal and to differentiate into almost all the cell types in the human body. Elucidation of molecular mechanisms regulating stem cell potency and differentiation is essential and critical for extensive application. Heterogeneous nuclear ribonucleoproteins (hnRNPs are modular proteins consisting of RNA-binding motifs and auxiliary domains characterized by extensive and divergent functions in nucleic acid metabolism. Multiple roles of hnRNPs in transcriptional and posttranscriptional regulation enable them to be effective gene expression regulators. More recent findings show that hnRNP proteins are crucial factors implicated in maintenance of stem cell self-renewal and pluripotency and cell differentiation. The hnRNPs interact with certain sequences in target gene promoter regions to initiate transcription. In addition, they recognize 3′UTR or 5′UTR of specific gene mRNA forming mRNP complex to regulate mRNA stability and translation. Both of these regulatory pathways lead to modulation of gene expression that is associated with stem cell proliferation, cell cycle control, pluripotency, and committed differentiation.

Ihh/Gli2 signaling promotes osteoblast differentiation by regulating Runx2 expression and function.

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Shimoyama, Atsuko; Wada, Masahiro; Ikeda, Fumiyo; Hata, Kenji; Matsubara, Takuma; Nifuji, Akira; Noda, Masaki; Amano, Katsuhiko; Yamaguchi, Akira; Nishimura, Riko; Yoneda, Toshiyuki

2007-07-01

Genetic and cell biological studies have indicated that Indian hedgehog (Ihh) plays an important role in bone development and osteoblast differentiation. However, the molecular mechanism by which Ihh regulates osteoblast differentiation is complex and remains to be fully elucidated. In this study, we investigated the role of Ihh signaling in osteoblast differentiation using mesenchymal cells and primary osteoblasts. We observed that Ihh stimulated alkaline phosphatase (ALP) activity, osteocalcin expression, and calcification. Overexpression of Gli2- but not Gli3-induced ALP, osteocalcin expression, and calcification of these cells. In contrast, dominant-negative Gli2 markedly inhibited Ihh-dependent osteoblast differentiation. Ihh treatment or Gli2 overexpression also up-regulated the expression of Runx2, an essential transcription factor for osteoblastogenesis, and enhanced the transcriptional activity and osteogenic action of Runx2. Coimmunoprecipitation analysis demonstrated a physical interaction between Gli2 and Runx2. Moreover, Ihh or Gli2 overexpression failed to increase ALP activity in Runx2-deficient mesenchymal cells. Collectively, these results suggest that Ihh regulates osteoblast differentiation of mesenchymal cells through up-regulation of the expression and function of Runx2 by Gli2.

TLX: A master regulator for neural stem cell maintenance and neurogenesis.

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Islam, Mohammed M; Zhang, Chun-Li

2015-02-01

The orphan nuclear receptor TLX, also known as NR2E1, is an essential regulator of neural stem cell (NSC) self-renewal, maintenance, and neurogenesis. In vertebrates, TLX is specifically localized to the neurogenic regions of the forebrain and retina throughout development and adulthood. TLX regulates the expression of genes involved in multiple pathways, such as the cell cycle, DNA replication, and cell adhesion. These roles are primarily performed through the transcriptional repression or activation of downstream target genes. Emerging evidence suggests that the misregulation of TLX might play a role in the onset and progression of human neurological disorders making this factor an ideal therapeutic target. Here, we review the current understanding of TLX function, expression, regulation, and activity significant to NSC maintenance, adult neurogenesis, and brain plasticity. This article is part of a Special Issue entitled: Nuclear receptors in animal development. Copyright © 2014 Elsevier B.V. All rights reserved.

Effects of Human Umbilical Cord Mesenchymal Stem Cells on Human Trophoblast Cell Functions In Vitro

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Yajing Huang

2016-01-01

Full Text Available Trophoblast cell dysfunction is involved in many disorders during pregnancy such as preeclampsia and intrauterine growth restriction. Few treatments exist, however, that target improving trophoblast cell function. Human umbilical cord mesenchymal stem cells (hUCMSCs are capable of self-renewing, can undergo multilineage differentiation, and have homing abilities; in addition, they have immunomodulatory effects and paracrine properties and thus are a prospective source for cell therapy. To identify whether hUCMSCs can regulate trophoblast cell functions, we treated trophoblast cells with hUCMSC supernatant or cocultured them with hUCMSCs. Both treatments remarkably enhanced the migration and invasion abilities of trophoblast cells and upregulated their proliferation ability. At a certain concentration, hUCMSCs also modulated hCG, PIGF, and sEndoglin levels in the trophoblast culture medium. Thus, hUCMSCs have a positive effect on trophoblast cellular functions, which may provide a new avenue for treatment of placenta-related diseases during pregnancy.

Dual role of miR-21 in CD4+ T-cells: activation-induced miR-21 supports survival of memory T-cells and regulates CCR7 expression in naive T-cells.

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Katarzyna Smigielska-Czepiel

Full Text Available Immune cell-type specific miRNA expression patterns have been described but the detailed role of single miRNAs in the function of T-cells remains largely unknown. We investigated the role of miR-21 in the function of primary human CD4+ T-cells. MiR-21 is substantially expressed in T-cells with a memory phenotype, and is robustly upregulated upon αCD3/CD28 activation of both naive and memory T-cells. By inhibiting the endogenous miR-21 function in activated naive and memory T-cells, we showed that miR-21 regulates fundamentally different aspects of T-cell biology, depending on the differentiation status of the T-cell. Stable inhibition of miR-21 function in activated memory T-cells led to growth disadvantage and apoptosis, indicating that the survival of memory T-cells depends on miR-21 function. In contrast, stable inhibition of miR-21 function in activated naive T-cells did not result in growth disadvantage, but led to a significant induction of CCR7 protein expression. Direct interaction between CCR7 and miR-21 was confirmed in a dual luciferase reporter assay. Our data provide evidence for a dual role of miR-21 in CD4+ T cells; Regulation of T-cell survival is confined to activated memory T-cells, while modulation of potential homing properties, through downregulation of CCR7 protein expression, is observed in activated naive T-cells.

Substrate Curvature Regulates Cell Migration -A Computational Study

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He, Xiuxiu; Jiang, Yi

Cell migration in host microenvironment is essential to cancer etiology, progression and metastasis. Cellular processes of adhesion, cytoskeletal polymerization, contraction, and matrix remodeling act in concert to regulate cell migration, while local extracellular matrix architecture modulate these processes. In this work we study how stromal microenvironment with native and cell-derived curvature at micron-meter scale regulate cell motility pattern. We developed a 3D model of single cell migration on a curved substrate. Mathematical analysis of cell morphological adaption to the cell-substrate interface shows that cell migration on convex surfaces deforms more than on concave surfaces. Both analytical and simulation results show that curved surfaces regulate the cell motile force for cell's protruding front through force balance with focal adhesion and cell contraction. We also found that cell migration on concave substrates is more persistent. These results offer a novel biomechanical explanation to substrate curvature regulation of cell migration. NIH 1U01CA143069.

A positive feedback regulation of ISL-1 in DLBCL but not in pancreatic β-cells

Energy Technology Data Exchange (ETDEWEB)

Zhang, Qiao, E-mail: zhangqiao200824@126.com [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences (Ministry of Education), Peking University, 38 Xueyuan Road, 100191 Beijing (China); Yang, Zhe, E-mail: zheyang@bjmu.edu.cn [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences (Ministry of Education), Peking University, 38 Xueyuan Road, 100191 Beijing (China); Wang, Weiping, E-mail: wwp@bjmu.edu.cn [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences (Ministry of Education), Peking University, 38 Xueyuan Road, 100191 Beijing (China); Guo, Ting, E-mail: luckyguoting@bjmu.edu.cn [Department of Gastrointestinal Translation Research, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital, 52 Fucheng Road, 100142 Beijing (China); Jia, Zhuqing, E-mail: zhuqingjia@126.com [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences (Ministry of Education), Peking University, 38 Xueyuan Road, 100191 Beijing (China); Ma, Kangtao, E-mail: makangtao11@126.com [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences (Ministry of Education), Peking University, 38 Xueyuan Road, 100191 Beijing (China); Zhou, Chunyan, E-mail: chunyanzhou@bjmu.edu.cn [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences (Ministry of Education), Peking University, 38 Xueyuan Road, 100191 Beijing (China)

2014-07-04

Highlights: • ISL-1 is highly expressed in human pancreatic β-cells and DLBCL. • ISL-1 accelerates the tumorigenesis of DLBCL in vivo. • c-Myc positively regulates ISL-1 expression in DLBCL but not in pancreatic β-cells. • ISL-1 and c-Myc forms an ISL-1/c-Myc transcriptional complex only in DLBCL. • Positive feedback regulation of ISL-1 does not exist in normal pancreatic β-cell. - Abstract: Insulin enhancer binding protein-1 (ISL-1), a LIM-homeodomain transcription factor, has been reported to play essential roles in promoting adult pancreatic β-cells proliferation. Recent studies indicate that ISL-1 may also involve in the occurrence of a variety of tumors. However, whether ISL-1 has any functional effect on tumorigenesis, and what are the differences on ISL-1 function in distinct conditions, are completely unknown. In this study, we found that ISL-1 was highly expressed in human pancreatic β-cells, as well as in diffuse large B cell lymphoma (DLBCL), but to a much less extent in other normal tissues or tumor specimens. Further study revealed that ISL-1 promoted the proliferation of pancreatic β-cells and DLBCL cells, and also accelerated the tumorigenesis of DLBCL in vivo. We also found that ISL-1 could activate c-Myc transcription not only in pancreatic β-cells but also in DLBCL cells. However, a cell-specific feedback regulation was detectable only in DLBCL cells. This auto-regulatory loop was established by the interaction of ISL-1 and c-Myc to form an ISL-1/c-Myc transcriptional complex, and synergistically to promote ISL-1 transcription through binding on the ISL-1 promoter. Taken together, our results demonstrate a positive feedback regulation of ISL-1 in DLBCL but not in pancreatic β-cells, which might result in the functional diversities of ISL-1 in different physiological and pathological processes.

A positive feedback regulation of ISL-1 in DLBCL but not in pancreatic β-cells

International Nuclear Information System (INIS)

Zhang, Qiao; Yang, Zhe; Wang, Weiping; Guo, Ting; Jia, Zhuqing; Ma, Kangtao; Zhou, Chunyan

2014-01-01

Highlights: • ISL-1 is highly expressed in human pancreatic β-cells and DLBCL. • ISL-1 accelerates the tumorigenesis of DLBCL in vivo. • c-Myc positively regulates ISL-1 expression in DLBCL but not in pancreatic β-cells. • ISL-1 and c-Myc forms an ISL-1/c-Myc transcriptional complex only in DLBCL. • Positive feedback regulation of ISL-1 does not exist in normal pancreatic β-cell. - Abstract: Insulin enhancer binding protein-1 (ISL-1), a LIM-homeodomain transcription factor, has been reported to play essential roles in promoting adult pancreatic β-cells proliferation. Recent studies indicate that ISL-1 may also involve in the occurrence of a variety of tumors. However, whether ISL-1 has any functional effect on tumorigenesis, and what are the differences on ISL-1 function in distinct conditions, are completely unknown. In this study, we found that ISL-1 was highly expressed in human pancreatic β-cells, as well as in diffuse large B cell lymphoma (DLBCL), but to a much less extent in other normal tissues or tumor specimens. Further study revealed that ISL-1 promoted the proliferation of pancreatic β-cells and DLBCL cells, and also accelerated the tumorigenesis of DLBCL in vivo. We also found that ISL-1 could activate c-Myc transcription not only in pancreatic β-cells but also in DLBCL cells. However, a cell-specific feedback regulation was detectable only in DLBCL cells. This auto-regulatory loop was established by the interaction of ISL-1 and c-Myc to form an ISL-1/c-Myc transcriptional complex, and synergistically to promote ISL-1 transcription through binding on the ISL-1 promoter. Taken together, our results demonstrate a positive feedback regulation of ISL-1 in DLBCL but not in pancreatic β-cells, which might result in the functional diversities of ISL-1 in different physiological and pathological processes

CP-25, a Novel Anti-inflammatory and Immunomodulatory Drug, Inhibits the Functions of Activated Human B Cells through Regulating BAFF and TNF-alpha Signaling and Comparative Efficacy with Biological Agents

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Feng Zhang

2017-12-01

Full Text Available Paeoniflorin-6′-O-benzene sulfonate (code: CP-25 was the chemistry structural modifications of Paeoniflorin (Pae. CP-25 inhibited B cells proliferation stimulated by B cell activating factor belonging to the TNF family (BAFF or Tumor necrosis factor alpha (TNF-alpha. CP-25, Rituximab and Etanercept reduced the percentage and numbers of CD19+ B cells, CD19+CD20+ B cells, CD19+CD27+ B cells and CD19+CD20+CD27+ B cells induced by BAFF or TNF-alpha. There was significant difference between CP-25 and Rituximab or CP-25 and Etanercept. CP-25 down-regulated the high expression of BAFFR, BCMA, and TACI stimulated by BAFF or TNF-alpha. The effects of Rituximab and Etanercept on BAFFR or BCMA were stronger than that of CP-25. CP-25, Rituximab and Etanercept down-regulated significantly the expression of TNFR1 and TNFR2 on B cell stimulated by BAFF or TNF-alpha. CP-25, Rituximab and Etanercept down-regulated the expression of MKK3, P-p38, P-p65, TRAF2, and p52 in B cells stimulated by BAFF and the expression of TRAF2 and P-p65 in B cells stimulated by TNF-alpha. These results suggest that CP-25 regulated moderately activated B cells function by regulating the classical and alternative NF-κB signaling pathway mediated by BAFF and TNF-alpha-TRAF2-NF-κB signaling pathway. This study suggests that CP-25 may be a promising anti-inflammatory immune and soft regulation drug.

CP-25, a Novel Anti-inflammatory and Immunomodulatory Drug, Inhibits the Functions of Activated Human B Cells through Regulating BAFF and TNF-alpha Signaling and Comparative Efficacy with Biological Agents.

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Zhang, Feng; Shu, Jin-Ling; Li, Ying; Wu, Yu-Jing; Zhang, Xian-Zheng; Han, Le; Tang, Xiao-Yu; Wang, Chen; Wang, Qing-Tong; Chen, Jing-Yu; Chang, Yan; Wu, Hua-Xun; Zhang, Ling-Ling; Wei, Wei

2017-01-01

Paeoniflorin-6'- O -benzene sulfonate (code: CP-25) was the chemistry structural modifications of Paeoniflorin (Pae). CP-25 inhibited B cells proliferation stimulated by B cell activating factor belonging to the TNF family (BAFF) or Tumor necrosis factor alpha (TNF-alpha). CP-25, Rituximab and Etanercept reduced the percentage and numbers of CD19 + B cells, CD19 + CD20 + B cells, CD19 + CD27 + B cells and CD19 + CD20 + CD27 + B cells induced by BAFF or TNF-alpha. There was significant difference between CP-25 and Rituximab or CP-25 and Etanercept. CP-25 down-regulated the high expression of BAFFR, BCMA, and TACI stimulated by BAFF or TNF-alpha. The effects of Rituximab and Etanercept on BAFFR or BCMA were stronger than that of CP-25. CP-25, Rituximab and Etanercept down-regulated significantly the expression of TNFR1 and TNFR2 on B cell stimulated by BAFF or TNF-alpha. CP-25, Rituximab and Etanercept down-regulated the expression of MKK3, P-p38, P-p65, TRAF2, and p52 in B cells stimulated by BAFF and the expression of TRAF2 and P-p65 in B cells stimulated by TNF-alpha. These results suggest that CP-25 regulated moderately activated B cells function by regulating the classical and alternative NF-κB signaling pathway mediated by BAFF and TNF-alpha-TRAF2-NF-κB signaling pathway. This study suggests that CP-25 may be a promising anti-inflammatory immune and soft regulation drug.

Cell density and N-cadherin interactions regulate cell proliferation in the sensory epithelia of the inner ear.

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Warchol, Mark E

2002-04-01

Sensory hair cells in the inner ears of nonmammalian vertebrates can regenerate after injury. In many species, replacement hair cells are produced by the proliferation of epithelial supporting cells. Thus, the ability of supporting cells to undergo renewed proliferation is a key determinant of regenerative ability. The present study used cultures of isolated inner ear sensory epithelia to identify cellular signals that regulate supporting cell proliferation. Small pieces of sensory epithelia from the chicken utricle were cultured in glass microwells. Under those conditions, cell proliferation was inversely related to local cell density. The signaling molecules N-cadherin, beta-catenin, and focal adhesion kinase were immunolocalized in the cultured epithelial cells, and high levels of phosphotyrosine immunoreactivity were present at cell-cell junctions and focal contacts of proliferating cells. Binding of microbeads coated with a function-blocking antibody to N-cadherin inhibited ongoing proliferation. The growth of epithelial cells was also affected by the density of extracellular matrix molecules. The results suggest that cell density, cell-cell contact, and the composition of the extracellular matrix may be critical influences on the regulation of sensory regeneration in the inner ear.

A ROLE FOR INTERLEUKIN 8 IN DIRECT REGULATION OF T CELL FUNCTIONAL ACTIVITY

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M. E. Meniailo

2017-01-01

Full Text Available CD3+T lymphocytes were isolated from normal donors by positive magnetic separation. Activation of the T cells with particles conjugated with antibodies to CD3, СD28 and СD2 molecules led to substantial increase in T cell production of interleukin-8 (IL-8. An interleukin-8 receptor (CXCR1, CD181 was initially expressed in 13.3% of T lymphocytes. Activation of T lymphocytes resulted into a detectable increase of CD181+ cell number among CD4+ naïve cells and CD4+ terminally-differentiated effector cells, and, conversely, into decrease of their number among CD4+ effector memory cells. Activation of T lymphocytes was assessed by membrane expression of CD25 molecule (receptor for IL-2. IL-8 (0.01-10.0 ng/ml was shown to markedly reduce activation of both CD4- and CD4+ effector memory T cells, as well as terminallydifferentiated T effectors, without significantly affecting activation of naive T lymphocytes and central memory T cells. IL-8 noticeably increased IL-2 production by activated Т cells, caused a reduced IL-10 production, and did not significantly affect the secretion of IFNγ and IL-4. The data obtained suggest a significance of IL-8 for direct regulation of adaptive T cell responses.

A role for the retinoblastoma protein as a regulator of mouse osteoblast cell adhesion: implications for osteogenesis and osteosarcoma formation.

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Bernadette Sosa-García

2010-11-01

Full Text Available The retinoblastoma protein (pRb is a cell cycle regulator inactivated in most human cancers. Loss of pRb function results from mutations in the gene coding for pRb or for any of its upstream regulators. Although pRb is predominantly known as a cell cycle repressor, our data point to additional pRb functions in cell adhesion. Our data show that pRb regulates the expression of a wide repertoire of cell adhesion genes and regulates the assembly of the adherens junctions required for cell adhesion. We conducted our studies in osteoblasts, which depend on both pRb and on cell-to-cell contacts for their differentiation and function. We generated knockout mice in which the RB gene was excised specifically in osteoblasts using the cre-lox P system and found that osteoblasts from pRb knockout mice did not assemble adherens junction at their membranes. pRb depletion in wild type osteoblasts using RNAi also disrupted adherens junctions. Microarrays comparing pRb-expressing and pRb-deficient osteoblasts showed that pRb controls the expression of a number of cell adhesion genes, including cadherins. Furthermore, pRb knockout mice showed bone abnormalities consistent with osteoblast adhesion defects. We also found that pRb controls the function of merlin, a well-known regulator of adherens junction assembly, by repressing Rac1 and its effector Pak1. Using qRT-PCR, immunoblots, co-immunoprecipitation assays, and immunofluorescent labeling, we observed that pRb loss resulted in Rac1 and Pak1 overexpression concomitant with merlin inactivation by Pak1, merlin detachment from the membrane, and adherens junction loss. Our data support a pRb function in cell adhesion while elucidating the mechanism for this function. Our work suggests that in some tumor types pRb inactivation results in both a loss of cell cycle control that promotes initial tumor growth as well as in a loss of cell-to-cell contacts, which contributes to later stages of metastasis.

Cannabinoids Regulate Bcl-2 and Cyclin D2 Expression in Pancreatic β Cells.

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Jihye Kim

Full Text Available Recent reports have shown that cannabinoid 1 receptors (CB1Rs are expressed in pancreatic β cells, where they induce cell death and cell cycle arrest by directly inhibiting insulin receptor activation. Here, we report that CB1Rs regulate the expression of the anti-apoptotic protein Bcl-2 and cell cycle regulator cyclin D2 in pancreatic β cells. Treatment of MIN6 and βTC6 cells with a synthetic CB1R agonist, WIN55,212-2, led to a decrease in the expression of Bcl-2 and cyclin D2, in turn inducing cell cycle arrest in G0/G1 phase and caspase-3-dependent apoptosis. Additionally, genetic deletion and pharmacological blockade of CB1Rs after injury in mice led to increased levels of Bcl-2 and cyclin D2 in pancreatic β cells. These findings provide evidence for the involvement of Bcl-2 and cyclin D2 mediated by CB1Rs in the regulation of β-cell survival and growth, and will serve as a basis for developing new therapeutic interventions to enhance β-cell function and growth in diabetes.

The putative bZIP transcription factor BzpN slows proliferation and functions in the regulation of cell density by autocrine signals in Dictyostelium.

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Jonathan E Phillips

Full Text Available The secreted proteins AprA and CfaD function as autocrine signals that inhibit cell proliferation in Dictyostelium discoideum, thereby regulating cell numbers by a negative feedback mechanism. We report here that the putative basic leucine zipper transcription factor BzpN plays a role in the inhibition of proliferation by AprA and CfaD. Cells lacking BzpN proliferate more rapidly than wild-type cells but do not reach a higher stationary density. Recombinant AprA inhibits wild-type cell proliferation but does not inhibit the proliferation of cells lacking BzpN. Recombinant CfaD also inhibits wild-type cell proliferation, but promotes the proliferation of cells lacking BzpN. Overexpression of BzpN results in a reduced cell density at stationary phase, and this phenotype requires AprA, CfaD, and the kinase QkgA. Conditioned media from high-density cells stops the proliferation of wild-type but not bzpN(- cells and induces a nuclear localization of a BzpN-GFP fusion protein, though this localization does not require AprA or CfaD. Together, the data suggest that BzpN is necessary for some but not all of the effects of AprA and CfaD, and that BzpN may function downstream of AprA and CfaD in a signal transduction pathway that inhibits proliferation.

The Putative bZIP Transcripton Factor BzpN Slows Proliferation and Functions in the Regulation of Cell Density by Autocrine Signals in Dictyostelium

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Phillips, Jonathan E.; Huang, Eryong; Shaulsky, Gad; Gomer, Richard H.

2011-01-01

The secreted proteins AprA and CfaD function as autocrine signals that inhibit cell proliferation in Dictyostelium discoideum, thereby regulating cell numbers by a negative feedback mechanism. We report here that the putative basic leucine zipper transcription factor BzpN plays a role in the inhibition of proliferation by AprA and CfaD. Cells lacking BzpN proliferate more rapidly than wild-type cells but do not reach a higher stationary density. Recombinant AprA inhibits wild-type cell proliferation but does not inhibit the proliferation of cells lacking BzpN. Recombinant CfaD also inhibits wild-type cell proliferation, but promotes the proliferation of cells lacking BzpN. Overexpression of BzpN results in a reduced cell density at stationary phase, and this phenotype requires AprA, CfaD, and the kinase QkgA. Conditioned media from high-density cells stops the proliferation of wild-type but not bzpN− cells and induces a nuclear localization of a BzpN-GFP fusion protein, though this localization does not require AprA or CfaD. Together, the data suggest that BzpN is necessary for some but not all of the effects of AprA and CfaD, and that BzpN may function downstream of AprA and CfaD in a signal transduction pathway that inhibits proliferation. PMID:21760904

The putative bZIP transcription factor BzpN slows proliferation and functions in the regulation of cell density by autocrine signals in Dictyostelium.

Science.gov (United States)

Phillips, Jonathan E; Huang, Eryong; Shaulsky, Gad; Gomer, Richard H

2011-01-01

The secreted proteins AprA and CfaD function as autocrine signals that inhibit cell proliferation in Dictyostelium discoideum, thereby regulating cell numbers by a negative feedback mechanism. We report here that the putative basic leucine zipper transcription factor BzpN plays a role in the inhibition of proliferation by AprA and CfaD. Cells lacking BzpN proliferate more rapidly than wild-type cells but do not reach a higher stationary density. Recombinant AprA inhibits wild-type cell proliferation but does not inhibit the proliferation of cells lacking BzpN. Recombinant CfaD also inhibits wild-type cell proliferation, but promotes the proliferation of cells lacking BzpN. Overexpression of BzpN results in a reduced cell density at stationary phase, and this phenotype requires AprA, CfaD, and the kinase QkgA. Conditioned media from high-density cells stops the proliferation of wild-type but not bzpN(-) cells and induces a nuclear localization of a BzpN-GFP fusion protein, though this localization does not require AprA or CfaD. Together, the data suggest that BzpN is necessary for some but not all of the effects of AprA and CfaD, and that BzpN may function downstream of AprA and CfaD in a signal transduction pathway that inhibits proliferation.

Regulation of Innate Lymphoid Cells by Aryl Hydrocarbon Receptor