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Sample records for hair cell differentiation

  1. Mammalian cochlear supporting cells can divide and trans-differentiate into hair cells.

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    White, Patricia M; Doetzlhofer, Angelika; Lee, Yun Shain; Groves, Andrew K; Segil, Neil

    2006-06-22

    Sensory hair cells of the mammalian organ of Corti in the inner ear do not regenerate when lost as a consequence of injury, disease, or age-related deafness. This contrasts with other vertebrates such as birds, where the death of hair cells causes surrounding supporting cells to re-enter the cell cycle and give rise to both new hair cells and supporting cells. It is not clear whether the lack of mammalian hair cell regeneration is due to an intrinsic inability of supporting cells to divide and differentiate or to an absence or blockade of regenerative signals. Here we show that post-mitotic supporting cells purified from the postnatal mouse cochlea retain the ability to divide and trans-differentiate into new hair cells in culture. Furthermore, we show that age-dependent changes in supporting cell proliferative capacity are due in part to changes in the ability to downregulate the cyclin-dependent kinase inhibitor p27(Kip1) (also known as Cdkn1b). These results indicate that postnatal mammalian supporting cells are potential targets for therapeutic manipulation.

  2. Inactivation of STAT3 Signaling Impairs Hair Cell Differentiation in the Developing Mouse Cochlea

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    Qianqian Chen

    2017-07-01

    Full Text Available Although STAT3 signaling is demonstrated to regulate sensory cell differentiation and regeneration in the zebrafish, its exact role is still unclear in mammalian cochleae. Here, we report that STAT3 and its activated form are specifically expressed in hair cells during mouse cochlear development. Importantly, conditional cochlear deletion of Stat3 leads to an inhibition on hair cell differentiation in mice in vivo and in vitro. By cell fate analysis, inactivation of STAT3 signaling shifts the cell division modes from asymmetric to symmetric divisions from supporting cells. Moreover, inhibition of Notch signaling stimulates STAT3 phosphorylation, and inactivation of STAT3 signaling attenuates production of supernumerary hair cells induced by a Notch pathway inhibitor. Our findings highlight an important role of the STAT3 signaling during mouse cochlear hair cell differentiation and may have clinical implications for the recovery of hair cell loss-induced hearing impairment.

  3. Differentiation of hepatocytes from induced pluripotent stem cells derived from human hair follicle mesenchymal stem cells.

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    Shi, Xu; Lv, Shuang; He, Xia; Liu, Xiaomei; Sun, Meiyu; Li, Meiying; Chi, Guangfan; Li, Yulin

    2016-10-01

    Due to the limitations of organ donors and immune rejection in severe liver diseases, stem cell-based therapy presents a promising application for tissue repair and regeneration. As a novel cell source, mesenchymal stem cells separated from human hair follicles (HF-MSCs) are convenient to obtain and have no age limit. To date, the differentiation of HF-MSCs into hepatocytes has not been reported. In this study, we explored whether HF-MSCs and HF-MSC-derived-induced pluripotent stem cells (HF-iPS) could differentiate into hepatocytes in vitro. Flow cytometry, Oil Red O stain and Alizarin Red stain were used to identify the characteristics of HF-MSCs. The expression of liver-specific gene was detected by immunofluorescence and Quantitative Polymerase Chain Reaction. Periodic Acid-Schiff stain, Indocyanine Green stain and Low-Density Lipoprotein stain were performed to evaluate the functions of induced hepatocyte-like cells (HLCs). HF-MSCs were unable to differentiate into HLCs using previously reported procedures for MSCs from other tissues. However, HF-iPS efficiently induced the generation of HLCs that expressed hepatocyte markers and drug metabolism-related genes. HF-iPS can be used as novel and alternative cellular tools for inducing hepatocytes in vitro, simultaneously benefiting from utilizing HF-MSCs as a noninvasive and convenient cell source for reprogramming.

  4. Tissue-engineered skin preserving the potential of epithelial cells to differentiate into hair after grafting.

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    Larouche, Danielle; Cuffley, Kristine; Paquet, Claudie; Germain, Lucie

    2011-03-01

    The aim of this study was to evaluate whether tissue-engineered skin produced in vitro was able to sustain growth of hair follicles in vitro and after grafting. Different tissues were designed. Dissociated newborn mouse keratinocytes or newborn mouse hair buds (HBs) were added onto dermal constructs consisting of a tissue-engineered cell-derived matrix elaborated from either newborn mouse or adult human fibroblasts cultured with ascorbic acid. After 7-21 days of maturation at the air-liquid interface, no hair was noticed in vitro. Epidermal differentiation was observed in all tissue-engineered skin. However, human fibroblast-derived tissue-engineered dermis (hD) promoted a thicker epidermis than mouse fibroblast-derived tissue-engineered dermis (mD). In association with mD, HBs developed epithelial cyst-like inclusions presenting outer root sheath-like attributes. In contrast, epidermoid cyst-like inclusions lined by a stratified squamous epithelium were present in tissues composed of HBs and hD. After grafting, pilo-sebaceous units formed and hair grew in skin elaborated from HBs cultured 10-26 days submerged in culture medium in association with mD. However, the number of normal hair follicles decreased with longer culture time. This hair-forming capacity after grafting was not observed in tissues composed of hD overlaid with HBs. These results demonstrate that epithelial stem cells can be kept in vitro in a permissive tissue-engineered dermal environment without losing their potential to induce hair growth after grafting.

  5. A Case of Basal Cell Carcinoma with Outer Hair Follicle Sheath Differentiation

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    Masazumi Onishi

    2015-12-01

    Full Text Available A 70-year-old Japanese man presented at our hospital with an asymptomatic, blackish, irregularly shaped plaque with a gray nodule in the periphery on his left lower leg. The lesion had been present for 10 years and had recently enlarged, associated with bleeding. Histopathologically, the tumor consisted of three distinct parts: The first part showed massive aggregation of basophilic basaloid cells with peripheral palisading and abundant melanin granules, and was diagnosed as solid-type basal cell carcinoma. The second part showed aggregation of clear cells with squamous eddies, and was diagnosed as proliferating trichilemmal tumor. The third part showed reticular aggregation of basaloid cells with infundibular cysts in the papillary dermis, and was diagnosed as infundibulocystic basal cell carcinoma. We diagnosed this tumor as basal cell carcinoma with various forms of hair follicle differentiation, including differentiation into the outer root sheath.

  6. The structural and functional differentiation of hair cells in a lizard's basilar papilla suggests an operational principle of amniote cochleas.

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    Chiappe, M Eugenia; Kozlov, Andrei S; Hudspeth, A J

    2007-10-31

    The hair cells in the mammalian cochlea are of two distinct types. Inner hair cells are responsible for transducing mechanical stimuli into electrical responses, which they forward to the brain through a copious afferent innervation. Outer hair cells, which are thought to mediate the active process that sensitizes and tunes the cochlea, possess a negligible afferent innervation. For every inner hair cell, there are approximately three outer hair cells, so only one-quarter of the hair cells directly deliver information to the CNS. Although this is a surprising feature for a sensory system, the occurrence of a similar innervation pattern in birds and crocodilians suggests that the arrangement has an adaptive value. Using a lizard with highly developed hearing, the tokay gecko, we demonstrate in the present study that the same principle operates in a third major group of terrestrial animals. We propose that the differentiation of hair cells into signaling and amplifying classes reflects incompatible strategies for the optimization of mechanoelectrical transduction and of an active process based on active hair-bundle motility.

  7. A central to peripheral progression of cell cycle exit and hair cell differentiation in the developing mouse cristae.

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    Slowik, Amber D; Bermingham-McDonogh, Olivia

    2016-03-01

    The inner ear contains six distinct sensory organs that each maintains some ability to regenerate hair cells into adulthood. In the postnatal cochlea, there appears to be a relationship between the developmental maturity of a region and its ability to regenerate as postnatal regeneration largely occurs in the apical turn, which is the last region to differentiate and mature during development. In the mature cristae there are also regional differences in regenerative ability, which led us to hypothesize that there may be a general relationship between the relative maturity of a region and the regenerative competence of that region in all of the inner ear sensory organs. By analyzing adult mouse cristae labeled embryonically with BrdU, we found that hair cell birth starts in the central region and progresses to the periphery with age. Since the peripheral region of the adult cristae also maintains active Notch signaling and some regenerative competence, these results are consistent with the hypothesis that the last regions to develop retain some of their regenerative ability into adulthood. Further, by analyzing embryonic day 14.5 inner ears we provide evidence for a wave of hair cell birth along the longitudinal axis of the cristae from the central regions to the outer edges. Together with the data from the adult inner ears labeled with BrdU as embryos, these results suggest that hair cell differentiation closely follows cell cycle exit in the cristae, unlike in the cochlea where they are uncoupled. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Inactivation of STAT3 Signaling Impairs Hair Cell Differentiation in the Developing Mouse Cochlea.

    Science.gov (United States)

    Chen, Qianqian; Quan, Yizhou; Wang, Naitao; Xie, Chengying; Ji, Zhongzhong; He, Hao; Chai, Renjie; Li, Huawei; Yin, Shankai; Chin, Y Eugene; Wei, Xunbin; Gao, Wei-Qiang

    2017-07-11

    Although STAT3 signaling is demonstrated to regulate sensory cell differentiation and regeneration in the zebrafish, its exact role is still unclear in mammalian cochleae. Here, we report that STAT3 and its activated form are specifically expressed in hair cells during mouse cochlear development. Importantly, conditional cochlear deletion of Stat3 leads to an inhibition on hair cell differentiation in mice in vivo and in vitro. By cell fate analysis, inactivation of STAT3 signaling shifts the cell division modes from asymmetric to symmetric divisions from supporting cells. Moreover, inhibition of Notch signaling stimulates STAT3 phosphorylation, and inactivation of STAT3 signaling attenuates production of supernumerary hair cells induced by a Notch pathway inhibitor. Our findings highlight an important role of the STAT3 signaling during mouse cochlear hair cell differentiation and may have clinical implications for the recovery of hair cell loss-induced hearing impairment. Copyright © 2017 International Society for Stem Cell Research. Published by Elsevier Inc. All rights reserved.

  9. A novel Atoh1 "self-terminating" mouse model reveals the necessity of proper Atoh1 level and duration for hair cell differentiation and viability.

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    Ning Pan

    Full Text Available Atonal homolog1 (Atoh1 is a bHLH transcription factor essential for inner ear hair cell differentiation. Targeted expression of Atoh1 at various stages in development can result in hair cell differentiation in the ear. However, the level and duration of Atoh1 expression required for proper hair cell differentiation and maintenance remain unknown. We generated an Atoh1 conditional knockout (CKO mouse line using Tg(Atoh1-cre, in which the cre expression is driven by an Atoh1 enhancer element that is regulated by Atoh1 protein to "self-terminate" its expression. The mutant mice show transient, limited expression of Atoh1 in all hair cells in the ear. In the organ of Corti, reduction and delayed deletion of Atoh1 result in progressive loss of almost all the inner hair cells and the majority of the outer hair cells within three weeks after birth. The remaining cells express hair cell marker Myo7a and attract nerve fibers, but do not differentiate normal stereocilia bundles. Some Myo7a-positive cells persist in the cochlea into adult stages in the position of outer hair cells, flanked by a single row of pillar cells and two to three rows of disorganized Deiters cells. Gene expression analyses of Atoh1, Barhl1 and Pou4f3, genes required for survival and maturation of hair cells, reveal earlier and higher expression levels in the inner compared to the outer hair cells. Our data show that Atoh1 is crucial for hair cell mechanotransduction development, viability, and maintenance and also suggest that Atoh1 expression level and duration may play a role in inner vs. outer hair cell development. These genetically engineered Atoh1 CKO mice provide a novel model for establishing critical conditions needed to regenerate viable and functional hair cells with Atoh1 therapy.

  10. miR-96 regulates the progression of differentiation in mammalian cochlear inner and outer hair cells.

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    Kuhn, Stephanie; Johnson, Stuart L; Furness, David N; Chen, Jing; Ingham, Neil; Hilton, Jennifer M; Steffes, Georg; Lewis, Morag A; Zampini, Valeria; Hackney, Carole M; Masetto, Sergio; Holley, Matthew C; Steel, Karen P; Marcotti, Walter

    2011-02-08

    MicroRNAs (miRNAs) are small noncoding RNAs able to regulate a broad range of protein-coding genes involved in many biological processes. miR-96 is a sensory organ-specific miRNA expressed in the mammalian cochlea during development. Mutations in miR-96 cause nonsyndromic progressive hearing loss in humans and mice. The mouse mutant diminuendo has a single base change in the seed region of the Mir96 gene leading to widespread changes in the expression of many genes. We have used this mutant to explore the role of miR-96 in the maturation of the auditory organ. We found that the physiological development of mutant sensory hair cells is arrested at around the day of birth, before their biophysical differentiation into inner and outer hair cells. Moreover, maturation of the hair cell stereocilia bundle and remodelling of auditory nerve connections within the cochlea fail to occur in miR-96 mutants. We conclude that miR-96 regulates the progression of the physiological and morphological differentiation of cochlear hair cells and, as such, coordinates one of the most distinctive functional refinements of the mammalian auditory system.

  11. The structural and functional differentiation of hair cells in a lizard’s basilar papilla suggests an operational principle of amniote cochleas

    Science.gov (United States)

    Chiappe, M. Eugenia; Kozlov, Andrei S.; Hudspeth, A. J.

    2007-01-01

    The hair cells in the mammalian cochlea are of two distinct types. Inner hair cells are responsible for transducing mechanical stimuli into electrical responses, which they forward to the brain through a copious afferent innervation. Outer hair cells, which are thought to mediate the active process that sensitizes and tunes the cochlea, possess a negligible afferent innervation. For every inner hair cell there are approximately three outer hair cells, so only a quarter of the hair cells directly deliver information to the central nervous system. Although this is a surprising feature for a sensory system, the occurrence of a similar innervation pattern in birds and crocodilians suggests that the arrangement has an adaptive value. Using a lizard with highly developed hearing, the tokay gecko, we demonstrate in the present study that the same principle operates in a third major group of terrestrial animals. We propose that the differentiation of hair cells into signaling and amplifying classes reflects incompatible strategies for the optimization of mechanoelectrical transduction and of an active process based on active hair-bundle motility. PMID:17978038

  12. Gentamicin differentially alters cellular metabolism of cochlear hair cells as revealed by NAD(P)H fluorescence lifetime imaging

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    Zholudeva, Lyandysha V.; Ward, Kristina G.; Nichols, Michael G.; Smith, Heather Jensen

    2015-05-01

    Aminoglycoside antibiotics are implicated as culprits of hearing loss in more than 120,000 individuals annually. Research has shown that the sensory cells, but not supporting cells, of the cochlea are readily damaged and/or lost after use of such antibiotics. High-frequency outer hair cells (OHCs) show a greater sensitivity to antibiotics than high- and low-frequency inner hair cells (IHCs). We hypothesize that variations in mitochondrial metabolism account for differences in susceptibility. Fluorescence lifetime microscopy was used to quantify changes in NAD(P)H in sensory and supporting cells from explanted murine cochleae exposed to mitochondrial uncouplers, inhibitors, and an ototoxic antibiotic, gentamicin (GM). Changes in metabolic state resulted in a redistribution of NAD(P)H between subcellular fluorescence lifetime pools. Supporting cells had a significantly longer lifetime than sensory cells. Pretreatment with GM increased NAD(P)H intensity in high-frequency sensory cells, as well as the NAD(P)H lifetime within IHCs. GM specifically increased NAD(P)H concentration in high-frequency OHCs, but not in IHCs or pillar cells. Variations in NAD(P)H intensity in response to mitochondrial toxins and GM were greatest in high-frequency OHCs. These results demonstrate that GM rapidly alters mitochondrial metabolism, differentially modulates cell metabolism, and provides evidence that GM-induced changes in metabolism are significant and greatest in high-frequency OHCs.

  13. Neuronal differentiation of hair-follicle-bulge-derived stem cells co-cultured with mouse cochlear modiolus explants.

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    Timo Schomann

    Full Text Available Stem-cell-based repair of auditory neurons may represent an attractive therapeutic option to restore sensorineural hearing loss. Hair-follicle-bulge-derived stem cells (HFBSCs are promising candidates for this type of therapy, because they (1 have migratory properties, enabling migration after transplantation, (2 can differentiate into sensory neurons and glial cells, and (3 can easily be harvested in relatively high numbers. However, HFBSCs have never been used for this purpose. We hypothesized that HFBSCs can be used for cell-based repair of the auditory nerve and we have examined their migration and incorporation into cochlear modiolus explants and their subsequent differentiation. Modiolus explants obtained from adult wild-type mice were cultured in the presence of EF1α-copGFP-transduced HFBSCs, constitutively expressing copepod green fluorescent protein (copGFP. Also, modiolus explants without hair cells were co-cultured with DCX-copGFP-transduced HFBSCs, which demonstrate copGFP upon doublecortin expression during neuronal differentiation. Velocity of HFBSC migration towards modiolus explants was calculated, and after two weeks, co-cultures were fixed and processed for immunohistochemical staining. EF1α-copGFP HFBSC migration velocity was fast: 80.5 ± 6.1 μm/h. After arrival in the explant, the cells formed a fascicular pattern and changed their phenotype into an ATOH1-positive neuronal cell type. DCX-copGFP HFBSCs became green-fluorescent after integration into the explants, confirming neuronal differentiation of the cells. These results show that HFBSC-derived neuronal progenitors are migratory and can integrate into cochlear modiolus explants, while adapting their phenotype depending on this micro-environment. Thus, HFBSCs show potential to be employed in cell-based therapies for auditory nerve repair.

  14. Characterisation of cell cycle arrest and terminal differentiation in a maximally proliferative human epithelial tissue: Lessons from the human hair follicle matrix.

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    Purba, Talveen S; Brunken, Lars; Peake, Michael; Shahmalak, Asim; Chaves, Asuncion; Poblet, Enrique; Ceballos, Laura; Gandarillas, Alberto; Paus, Ralf

    2017-09-01

    Human hair follicle (HF) growth and hair shaft formation require terminal differentiation-associated cell cycle arrest of highly proliferative matrix keratinocytes. However, the regulation of this complex event remains unknown. CIP/KIP family member proteins (p21 CIP1 , p27 KIP1 and p57 KIP2 ) regulate cell cycle progression/arrest, endoreplication, differentiation and apoptosis. Since they have not yet been adequately characterized in the human HF, we asked whether and where CIP/KIP proteins localise in the human hair matrix and pre-cortex in relation to cell cycle activity and HF-specific epithelial cell differentiation that is marked by keratin 85 (K85) protein expression. K85 expression coincided with loss or reduction in cell cycle activity markers, including in situ DNA synthesis (EdU incorporation), Ki-67, phospho-histone H3 and cyclins A and B1, affirming a post-mitotic state of pre-cortical HF keratinocytes. Expression of CIP/KIP proteins was found abundantly within the proliferative hair matrix, concomitant with a role in cell cycle checkpoint control. p21 CIP1 , p27 KIP1 and cyclin E persisted within post-mitotic keratinocytes of the pre-cortex, whereas p57 KIP2 protein decreased but became nuclear. These data imply a supportive role for CIP/KIP proteins in maintaining proliferative arrest, differentiation and anti-apoptotic pathways, promoting continuous hair bulb growth and hair shaft formation in anagen VI. Moreover, post-mitotic hair matrix regions contained cells with enlarged nuclei, and DNA in situ hybridisation showed cells that were >2N in the pre-cortex. This suggests that CIP/KIP proteins might counterbalance cyclin E to control further rounds of DNA replication in a cell population that has a propensity to become tetraploid. These data shed new light on the in situ-biography of human hair matrix keratinocytes on their path of active cell cycling, arrest and terminal differentiation, and showcase the human HF as an excellent, clinically

  15. The pluripotency of hair follicle stem cells.

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    Hoffman, Robert M

    2006-02-01

    The hair follicle bulge area is an abundant, easily accessible source of actively growing, pluripotent adult stem cells. Nestin, a protein marker for neural stem cells, is also expressed in follicle stem cells as well as their immediate differentiated progeny. The nestin-expressing hair follicle stem cells differentiated into neurons, glial cells, keratinocytes and smooth muscle cells in vitro. Hair-follicle stem cells were implanted into the gap region of a severed sciatic nerve. The hair follicle stem cells greatly enhanced the rate of nerve regeneration and the restoration of nerve function. The follicle stem cells transdifferentiated largely into Schwann cells which are known to support neuron regrowth. Function of the rejoined sciatic nerve was measured by contraction of the gastrocnemius muscle upon electrical stimulation. After severing the tibial nerve and subsequent transplantation of hair-follicle stem cells, the transplanted mice recovered the ability to walk normally. These results suggest that hair-follicle stem cells provide an important accessible, autologous source of adult stem cells for regenerative medicine.

  16. Differentiation of human scalp hair follicle keratinocytes in culture.

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    Weterings, P J; Verhagen, H; Wirtz, P; Vermorken, A J

    1984-01-01

    The morphology of human scalp hair follicle keratinocytes, cultured on the bovine eye lens capsule, is studied by light and electron microscopy. The hair follicle keratinocytes in the stratified cultures are characterized by the presence of numerous tonofilaments, desmosomes and lysosomes and by the presence of glycogen accumulations. The cells in the upper layers develop a cornified envelope. Moreover, an incomplete basal lamina is found between the capsule and the basal cells. However, some features of epidermal keratinocytes in vivo, such as keratohyalin granules and stratum corneum formation, are absent. Analysis of the polypeptides by sodium dodecylsulfate polyacrylamide gel electrophoresis also reveals differences between the cultured hair follicle cells and epidermis, whilst the patterns of cultured cells and hair follicle sheaths are similar. The morphological and protein biosynthetic aspects of terminal differentiation of the keratinocytes in vitro are correlated. These results are discussed in the light of the findings with cultured epidermal keratinocytes, reported in the literature.

  17. LGR4 and LGR5 regulate hair cell differentiation in the sensory epithelium of the developing mouse cochlea

    NARCIS (Netherlands)

    Zak, Magdalena; Van Oort, Thijs; Hendriksen, Ferry G.; Garcia, Marie Isabelle; Vassart, Gilbert; Grolman, Wilko

    2016-01-01

    In the developing cochlea, Wnt/β-catenin signaling positively regulates the proliferation of precursors and promotes the formation of hair cells by up-regulating Atoh1 expression. Not much, however, is known about the regulation of Wnt/β-catenin activity in the cochlea. In multiple tissues, the

  18. LSD1 is Required for Hair Cell Regeneration in Zebrafish.

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    He, Yingzi; Tang, Dongmei; Cai, Chengfu; Chai, Renjie; Li, Huawei

    2016-05-01

    Lysine-specific demethylase 1 (LSD1/KDM1A) plays an important role in complex cellular processes such as differentiation, proliferation, apoptosis, and cell cycle progression. It has recently been demonstrated that during development, downregulation of LSD1 inhibits cell proliferation, modulates the expression of cell cycle regulators, and reduces hair cell formation in the zebrafish lateral line, which suggests that LSD1-mediated epigenetic regulation plays a key role in the development of hair cells. However, the role of LSD1 in hair cell regeneration after hair cell loss remains poorly understood. Here, we demonstrate the effect of LSD1 on hair cell regeneration following neomycin-induced hair cell loss. We show that the LSD1 inhibitor trans-2-phenylcyclopropylamine (2-PCPA) significantly decreases the regeneration of hair cells in zebrafish after neomycin damage. In addition, immunofluorescent staining demonstrates that 2-PCPA administration suppresses supporting cell proliferation and alters cell cycle progression. Finally, in situ hybridization shows that 2-PCPA significantly downregulates the expression of genes related to Wnt/β-catenin and Fgf activation. Altogether, our data suggest that downregulation of LSD1 significantly decreases hair cell regeneration after neomycin-induced hair cell loss through inactivation of the Wnt/β-catenin and Fgf signaling pathways. Thus, LSD1 plays a critical role in hair cell regeneration and might represent a novel biomarker and potential therapeutic approach for the treatment of hearing loss.

  19. Induction of Functional Hair-Cell-Like Cells from Mouse Cochlear Multipotent Cells

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    Quanwen Liu

    2016-01-01

    Full Text Available In this paper, we developed a two-step-induction method of generating functional hair cells from inner ear multipotent cells. Multipotent cells from the inner ear were established and induced initially into progenitor cells committed to the inner ear cell lineage on the poly-L-lysine substratum. Subsequently, the committed progenitor cells were cultured on the mitotically inactivated chicken utricle stromal cells and induced into hair-cell-like cells containing characteristic stereocilia bundles. The hair-cell-like cells exhibited rapid permeation of FM1-43FX. The whole-cell patch-clamp technique was used to measure the membrane currents of cells differentiated for 7 days on chicken utricle stromal cells and analyze the biophysical properties of the hair-cell-like cells by recording membrane properties of cells. The results suggested that the hair-cell-like cells derived from inner ear multipotent cells were functional following differentiation in an enabling environment.

  20. Palmitoylation regulates epidermal homeostasis and hair follicle differentiation.

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    Pleasantine Mill

    2009-11-01

    Full Text Available Palmitoylation is a key post-translational modification mediated by a family of DHHC-containing palmitoyl acyl-transferases (PATs. Unlike other lipid modifications, palmitoylation is reversible and thus often regulates dynamic protein interactions. We find that the mouse hair loss mutant, depilated, (dep is due to a single amino acid deletion in the PAT, Zdhhc21, resulting in protein mislocalization and loss of palmitoylation activity. We examined expression of Zdhhc21 protein in skin and find it restricted to specific hair lineages. Loss of Zdhhc21 function results in delayed hair shaft differentiation, at the site of expression of the gene, but also leads to hyperplasia of the interfollicular epidermis (IFE and sebaceous glands, distant from the expression site. The specific delay in follicle differentiation is associated with attenuated anagen propagation and is reflected by decreased levels of Lef1, nuclear beta-catenin, and Foxn1 in hair shaft progenitors. In the thickened basal compartment of mutant IFE, phospho-ERK and cell proliferation are increased, suggesting increased signaling through EGFR or integrin-related receptors, with a parallel reduction in expression of the key differentiation factor Gata3. We show that the Src-family kinase, Fyn, involved in keratinocyte differentiation, is a direct palmitoylation target of Zdhhc21 and is mislocalized in mutant follicles. This study is the first to demonstrate a key role for palmitoylation in regulating developmental signals in mammalian tissue homeostasis.

  1. A function for Rac1 in the terminal differentiation and pigmentation of hair

    DEFF Research Database (Denmark)

    Behrendt, Kristina; Klatte, Jennifer; Pofahl, Ruth

    2012-01-01

    in the regulation of terminal hair follicle differentiation. To address this, we have expressed a constitutively active mutant of Rac1, L61Rac1, only in the basal epidermal layer and outer root sheath of mice possessing an epidermis-specific deletion of endogenous Rac1, which experience severe hair loss......The small GTPase Rac1 is ubiquitously expressed in proliferating and differentiating layers of the epidermis and hair follicles. Previously, Rac1 was shown to regulate stem cell behaviour in these compartments. We have asked whether Rac1 has, in addition, a specific, stem-cell-independent function....... The resulting 'rescue' mice exhibited a hair coat throughout their lives. Therefore, expression of Rac1 activity in the keratin-14-positive compartment of the skin is sufficient for the formation of hair follicles and hair in normal quantities. The quality of hair formed in rescue mice was, however, not normal...

  2. Stimulation of hair cells with ultraviolet light

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    Azimzadeh, Julien B.; Fabella, Brian A.; Hudspeth, A. J.

    2018-05-01

    Hair bundles are specialized organelles that transduce mechanical inputs into electrical outputs. To activate hair cells, physiologists have resorted to mechanical methods of hair-bundle stimulation. Here we describe a new method of hair-bundle stimulation, irradiation with ultraviolet light. A hair bundle illuminated by ultraviolet light rapidly moves towards its tall edge, a motion typically associated with excitatory stimulation. The motion disappears upon tip-link rupture and is associated with the opening of mechanotransduction channels. Hair bundles can be induced to move sinusoidally with oscillatory modulation of the stimulation power. We discuss the implications of ultraviolet stimulation as a novel hair-bundle stimulus.

  3. Hair cell regeneration in the avian auditory epithelium.

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    Stone, Jennifer S; Cotanche, Douglas A

    2007-01-01

    Regeneration of sensory hair cells in the mature avian inner ear was first described just over 20 years ago. Since then, it has been shown that many other non-mammalian species either continually produce new hair cells or regenerate them in response to trauma. However, mammals exhibit limited hair cell regeneration, particularly in the auditory epithelium. In birds and other non-mammals, regenerated hair cells arise from adjacent non-sensory (supporting) cells. Hair cell regeneration was initially described as a proliferative response whereby supporting cells re-enter the mitotic cycle, forming daughter cells that differentiate into either hair cells or supporting cells and thereby restore cytoarchitecture and function in the sensory epithelium. However, further analyses of the avian auditory epithelium (and amphibian vestibular epithelium) revealed a second regenerative mechanism, direct transdifferentiation, during which supporting cells change their gene expression and convert into hair cells without dividing. In the chicken auditory epithelium, these two distinct mechanisms show unique spatial and temporal patterns, suggesting they are differentially regulated. Current efforts are aimed at identifying signals that maintain supporting cells in a quiescent state or direct them to undergo direct transdifferentiation or cell division. Here, we review current knowledge about supporting cell properties and discuss candidate signaling molecules for regulating supporting cell behavior, in quiescence and after damage. While significant advances have been made in understanding regeneration in non-mammals over the last 20 years, we have yet to determine why the mammalian auditory epithelium lacks the ability to regenerate hair cells spontaneously and whether it is even capable of significant regeneration under additional circumstances. The continued study of mechanisms controlling regeneration in the avian auditory epithelium may lead to strategies for inducing

  4. Myc and Fgf Are Required for Zebrafish Neuromast Hair Cell Regeneration.

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    Lee, Sang Goo; Huang, Mingqian; Obholzer, Nikolaus D; Sun, Shan; Li, Wenyan; Petrillo, Marco; Dai, Pu; Zhou, Yi; Cotanche, Douglas A; Megason, Sean G; Li, Huawei; Chen, Zheng-Yi

    2016-01-01

    Unlike mammals, the non-mammalian vertebrate inner ear can regenerate the sensory cells, hair cells, either spontaneously or through induction after hair cell loss, leading to hearing recovery. The mechanisms underlying the regeneration are poorly understood. By microarray analysis on a chick model, we show that chick hair cell regeneration involves the activation of proliferation genes and downregulation of differentiation genes. Both MYC and FGF are activated in chick hair cell regeneration. Using a zebrafish lateral line neuromast hair cell regeneration model, we show that the specific inhibition of Myc or Fgf suppresses hair cell regeneration, demonstrating that both pathways are essential to the process. Rapid upregulation of Myc and delayed Fgf activation during regeneration suggest a role of Myc in proliferation and Fgf in differentiation. The dorsal-ventral pattern of fgfr1a in the neuromasts overlaps with the distribution of hair cell precursors. By laser ablation, we show that the fgfr1a-positive supporting cells are likely the hair cell precursors that directly give rise to new hair cells; whereas the anterior-posterior fgfr1a-negative supporting cells have heightened proliferation capacity, likely to serve as more primitive progenitor cells to replenish lost precursors after hair cell loss. Thus fgfr1a is likely to mark compartmentalized supporting cell subtypes with different capacities in renewal proliferation and hair cell regeneration. Manipulation of c-MYC and FGF pathways could be explored for mammalian hair cell regeneration.

  5. Regional up-regulation of NOX2 contributes to the differential vulnerability of outer hair cells to neomycin.

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    Qi, Meihao; Qiu, Yang; Zhou, Xueying; Tian, Keyong; Zhou, Ke; Sun, Fei; Yue, Bo; Chen, Fuquan; Zha, Dingjun; Qiu, Jianhua

    2018-06-02

    In hearing loss induced by aminoglycoside antibiotics, the outer hair cells (OHCs) in the basal turn are always more susceptible than OHCs in the apical turn, while the underlying mechanisms remain unknown. In this study, we reported that NAPDH oxidase 2 (NOX2) played an important role in the OHCs damage preferentially in the basal turn. Normally, NOX2 was evenly expressed in OHCs among different turns, at a relatively low level. However, after neomycin treatment, NOX2 was dominantly induced in OHCs in the basal turn. In vivo and in vitro studies demonstrated that inhibition of NOX2 significantly alleviated neomycin-induced OHCs damages, as seen from both the cleaved caspase-3 and TUNEL staining. Moreover, gp91 ds-tat delivery and DHE staining results showed that NOX2-derived ROS was responsible for neomycin ototoxicity. Taken together, our study shows that regional up-expression of NOX2 and subsequent increase of ROS in OHCs of the basal turn is an important factor contributing to the vulnerability of OHCs there, which should shed light on the prevention of hearing loss induced by aminoglycoside antibiotics. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. Improved biolistic transfection of hair cells.

    Directory of Open Access Journals (Sweden)

    Hongyu Zhao

    Full Text Available Transient transfection of hair cells has proven challenging. Here we describe modifications to the Bio-Rad Helios Gene Gun that, along with an optimized protocol, improve transfection of bullfrog, chick, and mouse hair cells. The increased penetrating power afforded by our method allowed us to transfect mouse hair cells from the basal side, through the basilar membrane; this configuration protects hair bundles from damage during the procedure. We characterized the efficiency of transfection of mouse hair cells with fluorescently-tagged actin fusion protein using both the optimized procedure and a published procedure; while the efficiency of the two methods was similar, the morphology of transfected hair cells was improved with the new procedure. In addition, using the improved method, we were able to transfect hair cells in the bullfrog sacculus and chick cochlea for the first time. We used fluorescent-protein fusions of harmonin b (USH1C and PMCA2 (ATP2B2; plasma-membrane Ca(2+-ATPase isoform 2 to examine protein distribution in hair cells. While PMCA2-EGFP localization was similar to endogenous PMCA2 detected with antibodies, high levels of harmonin-EGFP were found at stereocilia tapers in bullfrog and chick, but not mouse; by contrast, harmonin-EGFP was concentrated in stereocilia tips in mouse hair cells.

  7. Live cell imaging of Arabidopsis root hairs

    NARCIS (Netherlands)

    Ketelaar, T.

    2014-01-01

    Root hairs are tubular extensions from the root surface that expand by tip growth. This highly focused type of cell expansion, combined with position of root hairs on the surface of the root, makes them ideal cells for microscopic observation. This chapter describes the method that is routinely used

  8. Biophysics of Hair Cell Sensory Systems

    NARCIS (Netherlands)

    Duifhuis, Hendrikus; Horst, Johannes; van Dijk, Pim; van Netten, Sietse

    1993-01-01

    The last decade revealed to auditory researchers that hair cells can not only detect and process mechanical energy, but are also able to produce it. Thanks to the active hair cell, ears can produce otoacoustic emissions. This book gives the newest insights into the biophysics and physiology of

  9. Zebrafish hair cell mechanics and physiology through the lens of noise-induced hair cell death

    Science.gov (United States)

    Coffin, Allison B.; Xu, Jie; Uribe, Phillip M.

    2018-05-01

    Hair cells are exquisitely sensitive to auditory stimuli, but also to damage from a variety of sources including noise trauma and ototoxic drugs. Mammals cannot regenerate cochlear hair cells, while non-mammalian vertebrates exhibit robust regenerative capacity. Our research group uses the lateral line system of larval zebrafish to explore the mechanisms underlying hair cell damage, identify protective therapies, and determine molecular drivers of innate regeneration. The lateral line system contains externally located sensory organs called neuromasts, each composed of ˜8-20 hair cells. Lateral line hair cells are homologous to vertebrate inner ear hair cells and share similar susceptibility to ototoxic damage. In the last decade, the lateral line has emerged as a powerful model system for understanding hair cell death mechanisms and for identifying novel protective compounds. Here we demonstrate that the lateral line is a tractable model for noise-induced hair cell death. We have developed a novel noise damage system capable of inducing over 50% loss of lateral line hair cells, with hair cell death occurring in a dose- and time-dependent manner. Cell death is greatest 72 hours post-exposure. However, early signs of hair cell damage, including changes in membrane integrity and reduced mechanotransduction, are apparent within hours of noise exposure. These features, early signs of damage followed by delayed hair cell death, are consistent with mammalian data, suggesting that noise acts similarly on zebrafish and mammalian hair cells. In our future work we will use our new model system to investigate noise damage events in real time, and to develop protective therapies for future translational research.

  10. Study of inner ear and lateral line hair cell regeneration

    OpenAIRE

    Piqué Borràs, Maria Riera

    2013-01-01

    Death of sensory hair cells in the inner ear results in two global health problems that millions of people around the world suffer: hearing loss and balance disorders. Hair cells convert sound vibrations and head movements into electrical signals that are conveyed to the brain, and as a result of aging, exposure to noise, modern drugs or genetic predisposition, hair cells die. In mammals, the great majority of hair cells are produced during embryogenesis, and hair cells that ar...

  11. Hair follicle stem cell proliferation, Akt and Wnt signaling activation in TPA-induced hair regeneration.

    Science.gov (United States)

    Qiu, Weiming; Lei, Mingxing; Zhou, Ling; Bai, Xiufeng; Lai, Xiangdong; Yu, Yu; Yang, Tian; Lian, Xiaohua

    2017-06-01

    Regeneration of hair follicles relies on activation of hair follicle stem cells during telogen to anagen transition process in hair cycle. This process is rigorously controlled by intrinsic and environmental factors. 12-o-tetradecanoylphorbol-13-acetate (TPA), a tumor promoter, accelerates reentry of hair follicles into anagen phase. However, it is unclear that how TPA promotes the hair regeneration. In the present study, we topically applied TPA onto the dorsal skin of 2-month-old C57BL/6 female mice to examine the activity of hair follicle stem cells and alteration of signaling pathways during hair regeneration. We found that refractory telogen hair follicles entered anagen prematurely after TPA treatment, with the enhanced proliferation of CD34-positive hair follicle stem cells. Meanwhile, we observed Akt signaling was activated in epidermis, hair infundibulum, bulge and hair bulb, and Wnt signaling was also activated after hair follicle stem cells proliferation. Importantly, after overexpression of DKK1, a specific Wnt signaling inhibitor, the accelerated reentry of hair follicles into anagen induced by TPA was abolished. Our data indicated that TPA-induced hair follicle regeneration is associated with activation of Akt and Wnt/β-catenin signaling.

  12. Limited hair cell induction from human induced pluripotent stem cells using a simple stepwise method.

    Science.gov (United States)

    Ohnishi, Hiroe; Skerleva, Desislava; Kitajiri, Shin-ichiro; Sakamoto, Tatsunori; Yamamoto, Norio; Ito, Juichi; Nakagawa, Takayuki

    2015-07-10

    Disease-specific induced pluripotent stem cells (iPS) cells are expected to contribute to exploring useful tools for studying the pathophysiology of inner ear diseases and to drug discovery for treating inner ear diseases. For this purpose, stable induction methods for the differentiation of human iPS cells into inner ear hair cells are required. In the present study, we examined the efficacy of a simple induction method for inducing the differentiation of human iPS cells into hair cells. The induction of inner ear hair cell-like cells was performed using a stepwise method mimicking inner ear development. Human iPS cells were sequentially transformed into the preplacodal ectoderm, otic placode, and hair cell-like cells. As a first step, preplacodal ectoderm induction, human iPS cells were seeded on a Matrigel-coated plate and cultured in a serum free N2/B27 medium for 8 days according to a previous study that demonstrated spontaneous differentiation of human ES cells into the preplacodal ectoderm. As the second step, the cells after preplacodal ectoderm induction were treated with basic fibroblast growth factor (bFGF) for induction of differentiation into otic-placode-like cells for 15 days. As the final step, cultured cells were incubated in a serum free medium containing Matrigel for 48 days. After preplacodal ectoderm induction, over 90% of cultured cells expressed the genes that express in preplacodal ectoderm. By culture with bFGF, otic placode marker-positive cells were obtained, although their number was limited. Further 48-day culture in serum free media resulted in the induction of hair cell-like cells, which expressed a hair cell marker and had stereocilia bundle-like constructions on their apical surface. Our results indicate that hair cell-like cells are induced from human iPS cells using a simple stepwise method with only bFGF, without the use of xenogeneic cells. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  13. Implanted hair follicle stem cells form Schwann cells that support repair of severed peripheral nerves

    OpenAIRE

    Amoh, Yasuyuki; Li, Lingna; Campillo, Raul; Kawahara, Katsumasa; Katsuoka, Kensei; Penman, Sheldon; Hoffman, Robert M.

    2005-01-01

    The hair follicle bulge area is an abundant, easily accessible source of actively growing, pluripotent adult stem cells. Nestin, a protein marker for neural stem cells, also is expressed in follicle stem cells and their immediate, differentiated progeny. The fluorescent protein GFP, whose expression is driven by the nestin regulatory element in transgenic mice, served to mark the follicle cell fate. The pluripotent nestin-driven GFP stem cells are positive for the stem cell marker CD34 but ne...

  14. Regeneration of hair cells in the mammalian vestibular system.

    Science.gov (United States)

    Li, Wenyan; You, Dan; Chen, Yan; Chai, Renjie; Li, Huawei

    2016-06-01

    Hair cells regenerate throughout the lifetime of non-mammalian vertebrates, allowing these animals to recover from hearing and balance deficits. Such regeneration does not occur efficiently in humans and other mammals. Thus, balance deficits become permanent and is a common sensory disorder all over the world. Since Forge and Warchol discovered the limited spontaneous regeneration of vestibular hair cells after gentamicininduced damage in mature mammals, significant efforts have been exerted to trace the origin of the limited vestibular regeneration in mammals after hair cell loss. Moreover, recently many strategies have been developed to promote the hair cell regeneration and subsequent functional recovery of the vestibular system, including manipulating the Wnt, Notch and Atoh1. This article provides an overview of the recent advances in hair cell regeneration in mammalian vestibular epithelia. Furthermore, this review highlights the current limitations of hair cell regeneration and provides the possible solutions to regenerate functional hair cells and to partially restore vestibular function.

  15. Differential Expression of Proteins Associated with the Hair Follicle Cycle - Proteomics and Bioinformatics Analyses.

    Directory of Open Access Journals (Sweden)

    Lei Wang

    Full Text Available Hair follicle cycling can be divided into the following three stages: anagen, catagen, and telogen. The molecular signals that orchestrate the follicular transition between phases are still unknown. To better understand the detailed protein networks controlling this process, proteomics and bioinformatics analyses were performed to construct comparative protein profiles of mouse skin at specific time points (0, 8, and 20 days. Ninety-five differentially expressed protein spots were identified by MALDI-TOF/TOF as 44 proteins, which were found to change during hair follicle cycle transition. Proteomics analysis revealed that these changes in protein expression are involved in Ca2+-regulated biological processes, migration, and regulation of signal transduction, among other processes. Subsequently, three proteins were selected to validate the reliability of expression patterns using western blotting. Cluster analysis revealed three expression patterns, and each pattern correlated with specific cell processes that occur during the hair cycle. Furthermore, bioinformatics analysis indicated that the differentially expressed proteins impacted multiple biological networks, after which detailed functional analyses were performed. Taken together, the above data may provide insight into the three stages of mouse hair follicle morphogenesis and provide a solid basis for potential therapeutic molecular targets for this hair disease.

  16. Implanted hair follicle stem cells form Schwann cells that support repair of severed peripheral nerves.

    Science.gov (United States)

    Amoh, Yasuyuki; Li, Lingna; Campillo, Raul; Kawahara, Katsumasa; Katsuoka, Kensei; Penman, Sheldon; Hoffman, Robert M

    2005-12-06

    The hair follicle bulge area is an abundant, easily accessible source of actively growing, pluripotent adult stem cells. Nestin, a protein marker for neural stem cells, also is expressed in follicle stem cells and their immediate, differentiated progeny. The fluorescent protein GFP, whose expression is driven by the nestin regulatory element in transgenic mice, served to mark the follicle cell fate. The pluripotent nestin-driven GFP stem cells are positive for the stem cell marker CD34 but negative for keratinocyte marker keratin 15, suggesting their relatively undifferentiated state. These cells can differentiate into neurons, glia, keratinocytes, smooth muscle cells, and melanocytes in vitro. In vivo studies show the nestin-driven GFP hair follicle stem cells can differentiate into blood vessels and neural tissue after transplantation to the subcutis of nude mice. Equivalent hair follicle stem cells derived from transgenic mice with beta-actin-driven GFP implanted into the gap region of a severed sciatic nerve greatly enhance the rate of nerve regeneration and the restoration of nerve function. The follicle cells transdifferentiate largely into Schwann cells, which are known to support neuron regrowth. Function of the rejoined sciatic nerve was measured by contraction of the gastrocnemius muscle upon electrical stimulation. After severing the tibial nerve and subsequent transplantation of hair follicle stem cells, walking print length and intermediate toe spread significantly recovered, indicating that the transplanted mice recovered the ability to walk normally. These results suggest that hair follicle stem cells provide an important, accessible, autologous source of adult stem cells for regenerative medicine.

  17. The hair follicle bulge: a niche for adult stem cells.

    Science.gov (United States)

    Pasolli, Hilda Amalia

    2011-08-01

    Adult stem cells (SCs) are essential for tissue homeostasis and wound repair. They have the ability to both self-renew and differentiate into multiple cell types. They often reside in specialized microenvironments or niches that preserve their proliferative and tissue regenerative capacity. The murine hair follicle (HF) has a specialized and permanent compartment--the bulge, which safely lodges SCs and provides the necessary molecular cues to regulate their function. The HF undergoes cyclic periods of destruction, regeneration, and rest, making it an excellent system to study SC biology.

  18. Therapeutic potential of stem cells in auditory hair cell repair

    Directory of Open Access Journals (Sweden)

    Ryuji Hata

    2009-01-01

    Full Text Available The prevalence of acquired hearing loss is very high. About 10% of the total population and more than one third of the population over 65 years suffer from debilitating hearing loss. The most common type of hearing loss in adults is idiopathic sudden sensorineural hearing loss (ISSHL. In the majority of cases, ISSHL is permanent and typically associated with loss of sensory hair cells in the organ of Corti. Following the loss of sensory hair cells, the auditory neurons undergo secondary degeneration. Sensory hair cells and auditory neurons do not regenerate throughout life, and loss of these cells is irreversible and cumulative. However, recent advances in stem cell biology have gained hope that stem cell therapy comes closer to regenerating sensory hair cells in humans. A major advance in the prospects for the use of stem cells to restore normal hearing comes with the recent discovery that hair cells can be generated ex vivo from embryonic stem (ES cells, adult inner ear stem cells and neural stem cells. Furthermore, there is increasing evidence that stem cells can promote damaged cell repair in part by secreting diffusible molecules such as growth factors. These results suggest that stem-cell-based treatment regimens can be applicable to the damaged inner ear as future clinical applications.Previously we have established an animal model of cochlear ischemia in gerbils and showed progressive hair cell loss up to 4 days after ischemia. Auditory brain stem response (ABR recordings have demonstrated that this gerbil model displays severe deafness just after cochlear ischemia and gradually recovers thereafter. These pathological findings and clinical manifestations are reminiscent of ISSHL in humans. In this study, we have shown the effectiveness of stem cell therapy by using this animal model of ISSHL.

  19. Motility of vestibular hair cells in the chick.

    Science.gov (United States)

    Ogata, Y; Sekitani, T

    1993-01-01

    Recent studies of the outer hair cells in cochlea have demonstrated active motilities. However, very little study has been done on the vestibular hair cells (VHCs). The present study shows the motile response of the VHCs induced by application of Ca2+/ATP promoting contraction. Reversible cell shape changes could be shown in 10 of 16 isolated type I hair cells and 9 of 15 isolated type II hair cells by applying the contraction solution. Furthermore, the sensory hair bundles in the utricular epithelium pivoted around the base and stood perpendicularly to the apical borderline of the epithelium in response to the application of the same solution. It is suggested that the contraction of the isolated VHCs may be transferred to tension which causes the sensory hair bundles to restrict their motion in normal tissue, instead of changing the cell shape.

  20. Sensory hair cell death and regeneration in fishes

    Directory of Open Access Journals (Sweden)

    Jerry D. Monroe

    2015-04-01

    Full Text Available Sensory hair cells are specialized mechanotransductive receptors required for hearing and vestibular function. Loss of hair cells in humans and other mammals is permanent and causes reduced hearing and balance. In the early 1980’s, it was shown that hair cells continue to be added to the inner ear sensory epithelia in cartilaginous and bony fishes. Soon thereafter, hair cell regeneration was documented in the chick cochlea following acoustic trauma. Since then, research using chick and other avian models has led to great insights into hair cell death and regeneration. However, with the rise of the zebrafish as a model organism for studying disease and developmental processes, there has been an increased interest in studying sensory hair cell death and regeneration in its lateral line and inner ears. Advances derived from studies in zebrafish and other fish species include understanding the effect of ototoxins on hair cells and finding otoprotectants to mitigate ototoxin damage, the role of cellular proliferation versus direct transdifferentiation during hair cell regeneration, and elucidating cellular pathways involved in the regeneration process. This review will summarize research on hair cell death and regeneration using fish models, indicate the potential strengths and weaknesses of these models, and discuss several emerging areas of future studies.

  1. Neuromast hair cells retain the capacity of regeneration during heavy metal exposure.

    Science.gov (United States)

    Montalbano, G; Capillo, G; Laurà, R; Abbate, F; Levanti, M; Guerrera, M C; Ciriaco, E; Germanà, A

    2018-07-01

    The neuromast is the morphological unit of the lateral line of fishes and is composed of a cluster of central sensory cells (hair cells) surrounded by support and mantle cells. Heavy metals exposure leads to disruption of hair cells within the neuromast. It is well known that the zebrafish has the ability to regenerate the hair cells after damage caused by toxicants. The process of regeneration depends on proliferation, differentiation and cellular migration of sensory and non-sensory progenitor cells. Therefore, our study was made in order to identify which cellular types are involved in the complex process of regeneration during heavy metals exposure. For this purpose, adult zebrafish were exposed to various heavy metals (Arsenic, cadmium and zinc) for 72h. After acute (24h) exposure, immunohistochemical localization of S100 (a specific marker for hair cells) in the neuromasts highlighted the hair cells loss. The immunoreaction for Sox2 (a specific marker for stem cells), at the same time, was observed in the support and mantle cells, after exposure to arsenic and cadmium, while only in the support cells after exposure to zinc. After chronic (72h) exposure the hair cells were regenerated, showing an immunoreaction for S100 protein. At the same exposure time to the three metals, a Sox2 immunoreaction was expressed in support and mantle cells. Our results showed for the first time the regenerative capacity of hair cells, not only after, but also during exposure to heavy metals, demonstrated by the presence of different stem cells that can diversify in hair cells. Copyright © 2018 Elsevier GmbH. All rights reserved.

  2. Generation of inner ear organoids containing functional hair cells from human pluripotent stem cells.

    Science.gov (United States)

    Koehler, Karl R; Nie, Jing; Longworth-Mills, Emma; Liu, Xiao-Ping; Lee, Jiyoon; Holt, Jeffrey R; Hashino, Eri

    2017-06-01

    The derivation of human inner ear tissue from pluripotent stem cells would enable in vitro screening of drug candidates for the treatment of hearing and balance dysfunction and may provide a source of cells for cell-based therapies of the inner ear. Here we report a method for differentiating human pluripotent stem cells to inner ear organoids that harbor functional hair cells. Using a three-dimensional culture system, we modulate TGF, BMP, FGF, and WNT signaling to generate multiple otic-vesicle-like structures from a single stem-cell aggregate. Over 2 months, the vesicles develop into inner ear organoids with sensory epithelia that are innervated by sensory neurons. Additionally, using CRISPR-Cas9, we generate an ATOH1-2A-eGFP cell line to detect hair cell induction and demonstrate that derived hair cells exhibit electrophysiological properties similar to those of native sensory hair cells. Our culture system should facilitate the study of human inner ear development and research on therapies for diseases of the inner ear.

  3. Usher protein functions in hair cells and photoreceptors

    OpenAIRE

    Cosgrove, Dominic; Zallocchi, Marisa

    2013-01-01

    The 10 different genes associated with the deaf/blind disorder, Usher syndrome, encode a number of structurally and functionally distinct proteins, most expressed as multiple isoforms/protein variants. Functional characterization of these proteins suggests a role in stereocilia development in cochlear hair cells, likely owing to adhesive interactions in hair bundles. In mature hair cells, homodimers of the Usher cadherins, cadherin 23 and protocadherin 15, interact to form a structural fiber,...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

  6. Retinoic Acid Signaling Mediates Hair Cell Regeneration by Repressing p27kip and sox2 in Supporting Cells.

    Science.gov (United States)

    Rubbini, Davide; Robert-Moreno, Àlex; Hoijman, Esteban; Alsina, Berta

    2015-11-25

    During development, otic sensory progenitors give rise to hair cells and supporting cells. In mammalian adults, differentiated and quiescent sensory cells are unable to generate new hair cells when these are lost due to various insults, leading to irreversible hearing loss. Retinoic acid (RA) has strong regenerative capacity in several organs, but its role in hair cell regeneration is unknown. Here, we use genetic and pharmacological inhibition to show that the RA pathway is required for hair cell regeneration in zebrafish. When regeneration is induced by laser ablation in the inner ear or by neomycin treatment in the lateral line, we observe rapid activation of several components of the RA pathway, with dynamics that position RA signaling upstream of other signaling pathways. We demonstrate that blockade of the RA pathway impairs cell proliferation of supporting cells in the inner ear and lateral line. Moreover, in neuromast, RA pathway regulates the transcription of p27(kip) and sox2 in supporting cells but not fgf3. Finally, genetic cell-lineage tracing using Kaede photoconversion demonstrates that de novo hair cells derive from FGF-active supporting cells. Our findings reveal that RA has a pivotal role in zebrafish hair cell regeneration by inducing supporting cell proliferation, and shed light on the underlying transcriptional mechanisms involved. This signaling pathway might be a promising approach for hearing recovery. Hair cells are the specialized mechanosensory cells of the inner ear that capture auditory and balance sensory input. Hair cells die after acoustic trauma, ototoxic drugs or aging diseases, leading to progressive hearing loss. Mammals, in contrast to zebrafish, lack the ability to regenerate hair cells. Here, we find that retinoic acid (RA) pathway is required for hair cell regeneration in vivo in the zebrafish inner ear and lateral line. RA pathway is activated very early upon hair cell loss, promotes cell proliferation of progenitor cells

  7. Development and regeneration of vestibular hair cells in mammals.

    Science.gov (United States)

    Burns, Joseph C; Stone, Jennifer S

    2017-05-01

    Vestibular sensation is essential for gaze stabilization, balance, and perception of gravity. The vestibular receptors in mammals, Type I and Type II hair cells, are located in five small organs in the inner ear. Damage to hair cells and their innervating neurons can cause crippling symptoms such as vertigo, visual field oscillation, and imbalance. In adult rodents, some Type II hair cells are regenerated and become re-innervated after damage, presenting opportunities for restoring vestibular function after hair cell damage. This article reviews features of vestibular sensory cells in mammals, including their basic properties, how they develop, and how they are replaced after damage. We discuss molecules that control vestibular hair cell regeneration and highlight areas in which our understanding of development and regeneration needs to be deepened. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Mechanically Gated Ion Channels in Mammalian Hair Cells

    Directory of Open Access Journals (Sweden)

    Xufeng Qiu

    2018-04-01

    Full Text Available Hair cells in the inner ear convert mechanical stimuli provided by sound waves and head movements into electrical signal. Several mechanically evoked ionic currents with different properties have been recorded in hair cells. The search for the proteins that form the underlying ion channels is still in progress. The mechanoelectrical transduction (MET channel near the tips of stereociliary in hair cells, which is responsible for sensory transduction, has been studied most extensively. Several components of the sensory mechanotransduction machinery in stereocilia have been identified, including the multi-transmembrane proteins tetraspan membrane protein in hair cell stereocilia (TMHS/LHFPL5, transmembrane inner ear (TMIE and transmembrane channel-like proteins 1 and 2 (TMC1/2. However, there remains considerable uncertainty regarding the molecules that form the channel pore. In addition to the sensory MET channel, hair cells express the mechanically gated ion channel PIEZO2, which is localized near the base of stereocilia and not essential for sensory transduction. The function of PIEZO2 in hair cells is not entirely clear but it might have a role in damage sensing and repair processes. Additional stretch-activated channels of unknown molecular identity and function have been found to localize at the basolateral membrane of hair cells. Here, we review current knowledge regarding the different mechanically gated ion channels in hair cells and discuss open questions concerning their molecular composition and function.

  9. Sensory Hair Cells: An Introduction to Structure and Physiology.

    Science.gov (United States)

    McPherson, Duane R

    2018-06-18

    Sensory hair cells are specialized secondary sensory cells that mediate our senses of hearing, balance, linear acceleration, and angular acceleration (head rotation). In addition, hair cells in fish and amphibians mediate sensitivity to water movement through the lateral line system, and closely related electroreceptive cells mediate sensitivity to low-voltage electric fields in the aquatic environment of many fish species and several species of amphibian.Sensory hair cells share many structural and functional features across all vertebrate groups, while at the same time they are specialized for employment in a wide variety of sensory tasks. The complexity of hair cell structure is large, and the diversity of hair cell applications in sensory systems exceeds that seen for most, if not all, sensory cell types. The intent of this review is to summarize the more significant structural features and some of the more interesting and important physiological mechanisms that have been elucidated thus far. Outside vertebrates, hair cells are only known to exist in the coronal organ of tunicates. Electrical resonance, electromotility, and their exquisite mechanical sensitivity all contribute to the attractiveness of hair cells as a research subject.

  10. microRNA-183 is Essential for Hair Cell Regeneration after Neomycin Injury in Zebrafish.

    Science.gov (United States)

    Kim, Chang Woo; Han, Ji Hyuk; Wu, Ling; Choi, Jae Young

    2018-01-01

    microRNAs (miRNAs) are non-coding RNAs composed of 20 to 22 nucleotides that regulate development and differentiation in various organs by silencing specific RNAs and regulating gene expression. In the present study, we show that the microRNA (miR)-183 cluster is upregulated during hair cell regeneration and that its inhibition reduces hair cell regeneration following neomycin-induced ototoxicity in zebrafish. miRNA expression patterns after neomycin exposure were analyzed using microarray chips. Quantitative polymerase chain reaction was performed to validate miR-183 cluster expression patterns following neomycin exposure (500 μM for 2 h). After injection of an antisense morpholino (MO) to miR-183 (MO-183) immediately after fertilization, hair cell regeneration after neomycin exposure in neuromast cells was evaluated by fluorescent staining (YO-PRO1). The MO-183 effect also was assessed in transgenic zebrafish larvae expressing green fluorescent protein (GFP) in inner ear hair cells. Microarray analysis clearly showed that the miR-183 cluster (miR-96, miR-182, and miR-183) was upregulated after neomycin treatment. We also confirmed upregulated expression of the miR-183 cluster during hair cell regeneration after neomycin-induced ototoxicity. miR-183 inhibition using MO-183 reduced hair cell regeneration in both wild-type and GFP transgenic zebrafish larvae. Our work demonstrates that the miR-183 cluster is essential for the regeneration of hair cells following ototoxic injury in zebrafish larvae. Therefore, regulation of the miR-183 cluster can be a novel target for stimulation of hair cell regeneration. © Copyright: Yonsei University College of Medicine 2018

  11. Auditory hair cell centrioles undergo confined Brownian motion throughout the developmental migration of the kinocilium.

    Science.gov (United States)

    Lepelletier, Léa; de Monvel, Jacques Boutet; Buisson, Johanna; Desdouets, Chantal; Petit, Christine

    2013-07-02

    Planar polarization of the forming hair bundle, the mechanosensory antenna of auditory hair cells, depends on the poorly characterized center-to-edge displacement of a primary cilium, the kinocilium, at their apical surface. Taking advantage of the gradient of hair cell differentiation along the cochlea, we reconstituted a map of the kinocilia displacements in the mouse embryonic cochlea. We then developed a cochlear organotypic culture and video-microscopy approach to monitor the movements of the kinocilium basal body (mother centriole) and its daughter centriole, which we analyzed using particle tracking and modeling. We found that both hair cell centrioles undergo confined Brownian movements around their equilibrium positions, under the apparent constraint of a radial restoring force of ∼0.1 pN. This magnitude depended little on centriole position, suggesting nonlinear interactions with constraining, presumably cytoskeletal elements. The only dynamic change observed during the period of kinocilium migration was a doubling of the centrioles' confinement area taking place early in the process. It emerges from these static and dynamic observations that kinocilia migrate gradually in parallel with the organization of hair cells into rows during cochlear neuroepithelium extension. Analysis of the confined motion of hair cell centrioles under normal and pathological conditions should help determine which structures contribute to the restoring force exerting on them. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  12. Sensory hair cell regeneration in the zebrafish lateral line.

    Science.gov (United States)

    Lush, Mark E; Piotrowski, Tatjana

    2014-10-01

    Damage or destruction of sensory hair cells in the inner ear leads to hearing or balance deficits that can be debilitating, especially in older adults. Unfortunately, the damage is permanent, as regeneration of the inner ear sensory epithelia does not occur in mammals. Zebrafish and other non-mammalian vertebrates have the remarkable ability to regenerate sensory hair cells and understanding the molecular and cellular basis for this regenerative ability will hopefully aid us in designing therapies to induce regeneration in mammals. Zebrafish not only possess hair cells in the ear but also in the sensory lateral line system. Hair cells in both organs are functionally analogous to hair cells in the inner ear of mammals. The lateral line is a mechanosensory system found in most aquatic vertebrates that detects water motion and aids in predator avoidance, prey capture, schooling, and mating. Although hair cell regeneration occurs in both the ear and lateral line, most research to date has focused on the lateral line due to its relatively simple structure and accessibility. Here we review the recent discoveries made during the characterization of hair cell regeneration in zebrafish. Copyright © 2014 Wiley Periodicals, Inc.

  13. SENSORY HAIR CELL REGENERATION IN THE ZEBRAFISH LATERAL LINE

    Science.gov (United States)

    Lush, Mark E.; Piotrowski, Tatjana

    2014-01-01

    Damage or destruction of sensory hair cells in the inner ear leads to hearing or balance deficits that can be debilitating, especially in older adults. Unfortunately, the damage is permanent, as regeneration of the inner ear sensory epithelia does not occur in mammals. Zebrafish and other non-mammalian vertebrates have the remarkable ability to regenerate sensory hair cells and understanding the molecular and cellular basis for this regenerative ability will hopefully aid us in designing therapies to induce regeneration in mammals. Zebrafish not only possess hair cells in the ear but also in the sensory lateral line system. Hair cells in both organs are functionally analogous to hair cells in the inner ear of mammals. The lateral line is a mechanosensory system found in most aquatic vertebrates that detects water motion and aids in predator avoidance, prey capture, schooling and mating. Although hair cell regeneration occurs in both the ear and lateral line, most research to date has focused on the lateral line due to its relatively simple structure and accessibility. Here we review the recent discoveries made during the characterization of hair cell regeneration in zebrafish. PMID:25045019

  14. The design, calibration, and use of a water microjet for stimulating hair cell sensory hair bundles.

    Science.gov (United States)

    Saunders, J C; Szymko, Y M

    1989-11-01

    The design, calibration, and use of a noninvasive, noncontact device for stimulating hair cell hair bundles in vitro are described. This device employed a piezoelectric crystal, driven at high frequencies, to generate sinusoidal pressure in a contained fluid volume. The pressure was propagated to the tip of a glass micropipette and the oscillating water jet stimulus produced at the tip was used to stimulate sensory hair bundles. The movements of glass microbeads, caught in the oscillating pressure field of the water jet, provided a means of calibrating this stimulus. The linearity of the jet, its waveform and frequency response, the influence of pipette shape and tip diameter, as well as models to explain the operation of the water jet, are described. The use of this stimulus for measuring hair bundle micromechanics at high frequencies is then demonstrated.

  15. Outer hair cell piezoelectricity: frequency response enhancement and resonance behavior.

    Science.gov (United States)

    Weitzel, Erik K; Tasker, Ron; Brownell, William E

    2003-09-01

    Stretching or compressing an outer hair cell alters its membrane potential and, conversely, changing the electrical potential alters its length. This bi-directional energy conversion takes place in the cell's lateral wall and resembles the direct and converse piezoelectric effects both qualitatively and quantitatively. A piezoelectric model of the lateral wall has been developed that is based on the electrical and material parameters of the lateral wall. An equivalent circuit for the outer hair cell that includes piezoelectricity shows a greater admittance at high frequencies than one containing only membrane resistance and capacitance. The model also predicts resonance at ultrasonic frequencies that is inversely proportional to cell length. These features suggest all mammals use outer hair cell piezoelectricity to support the high-frequency receptor potentials that drive electromotility. It is also possible that members of some mammalian orders use outer hair cell piezoelectric resonance in detecting species-specific vocalizations.

  16. Numerical simulation of the hair formation -modeling of hair cycle

    Science.gov (United States)

    Kajihara, Narumichi; Nagayama, Katsuya

    2018-01-01

    In the recent years, the fields of study of anti-aging, health and beauty, cosmetics, and hair diseases have attracted significant attention. In particular, human hair is considered to be an important aspect with regard to an attractive appearance. To this end, many workers have sought to understand the formation mechanism of the hair root. However, observing growth in the hair root is difficult, and a detailed mechanism of the process has not yet been elucidated. Hair repeats growth, retraction, and pause cycles (hair cycle) in a repetitive process. In the growth phase, hair is formed through processes of cell proliferation and differentiation (keratinization). During the retraction phase, hair growth stops, and during the resting period, hair fall occurs and new hair grows. This hair cycle is believed to affect the elongation rate, thickness, strength, and shape of hair. Therefore, in this study, we introduce a particle model as a new method to elucidate the unknown process of hair formation, and to model the hair formation process accompanying the proliferation and differentiation of the hair root cells in all three dimensions. In addition, to the growth period, the retraction and the resting periods are introduced to realize the hair cycle using this model.

  17. Stem cell dynamics in the hair follicle niche

    Science.gov (United States)

    Rompolas, Panteleimon; Greco, Valentina

    2014-01-01

    Hair follicles are skin appendages of the mammalian skin that have the ability to periodically and stereotypically regenerate in order to continuously produce new hair over our lifetime. The ability of the hair follicle to regenerate is due to the presence of stem cells that along with other cell populations and non-cellular components, including molecular signals and extracellular material, make up a niche microenvironment. Mounting evidence suggests that the niche is critical for regulating stem cell behavior and thus the process of regeneration. Here we review the literature concerning past and current studies that have utilized mouse genetic models, combined with other approaches to dissect the molecular and cellular composition of the hair follicle niche. We also discuss our current understanding of how stem cells operate within the niche during the process of tissue regeneration and the factors that regulate their behavior. PMID:24361866

  18. Semicircular canals circumvent Brownian Motion overload of mechanoreceptor hair cells

    DEFF Research Database (Denmark)

    Muller, Mees; Heeck, Kier; Elemans, Coen P H

    2016-01-01

    Vertebrate semicircular canals (SCC) first appeared in the vertebrates (i.e. ancestral fish) over 600 million years ago. In SCC the principal mechanoreceptors are hair cells, which as compared to cochlear hair cells are distinctly longer (70 vs. 7 μm), 10 times more compliant to bending (44 vs. 500...... nN/m), and have a 100-fold higher tip displacement threshold (hair cells where the bundle is approximated as a stiff, cylindrical elastic rod subject to friction and thermal agitation. Our models suggest that the above...... differences aid SCC hair cells in circumventing the masking effects of Brownian motion noise of about 70 nm, and thereby permit transduction of very low frequency (

  19. Erythroid Differentiation Regulator 1 as a Novel Biomarker for Hair Loss Disorders.

    Science.gov (United States)

    Woo, Yu Ri; Hwang, Sewon; Jeong, Seo Won; Cho, Dae Ho; Park, Hyun Jeong

    2017-02-03

    Erythroid differentiation regulator 1 (Erdr1) is known to be involved in the inflammatory process via regulating the immune system in many cutaneous disorders, such as psoriasis and rosacea. However, the role of Erdr1 in various hair loss disorders remains unclear. The aim of this study was to investigate the putative role of Erdr1 in alopecias. Skin samples from 21 patients with hair loss disorders and five control subjects were retrieved, in order to assess their expression levels of Erdr1. Results revealed that expression of Erdr1 was significantly downregulated in the epidermis and hair follicles of patients with hair loss disorders, when compared to that in the control group. In particular, the expression of Erdr1 was significantly decreased in patients with alopecia areata. We propose that Erdr1 downregulation might be involved in the pathogenesis of hair loss, and could be considered as a novel biomarker for hair loss disorders.

  20. Falsification of the ionic channel theory of hair cell transduction.

    Science.gov (United States)

    Rossetto, Michelangelo

    2013-11-01

    The hair cell provides the transduction of mechanical vibrations in the balance and acoustic sense of all vertebrates that swim, walk, or fly. The current theory places hair cell transduction in a mechanically controlled ion channel. Although the theory of a mechanical input modulating the flow of ions through an ion pore has been a useful tool, it is falsified by experimental data in the literature and can be definitively falsified by a proposed experiment.

  1. SENSORY HAIR CELL REGENERATION IN THE ZEBRAFISH LATERAL LINE

    OpenAIRE

    Lush, Mark E.; Piotrowski, Tatjana

    2014-01-01

    Damage or destruction of sensory hair cells in the inner ear leads to hearing or balance deficits that can be debilitating, especially in older adults. Unfortunately, the damage is permanent, as regeneration of the inner ear sensory epithelia does not occur in mammals. Zebrafish and other non-mammalian vertebrates have the remarkable ability to regenerate sensory hair cells and understanding the molecular and cellular basis for this regenerative ability will hopefully aid us in designing ther...

  2. Gating energies and forces of the mammalian hair cell transducer channel and related hair bundle mechanics

    NARCIS (Netherlands)

    van Netten, SM; Kros, CJ

    2000-01-01

    We quantified the molecular energies and forces involved in opening and closing of mechanoelectrical transducer channels in hair cells using a novel generally applicable method. It relies on a thermodynamic description of the free energy of an ion channel in terms of its open probability. The

  3. Forensic Hair Differentiation Using Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectroscopy.

    Science.gov (United States)

    Manheim, Jeremy; Doty, Kyle C; McLaughlin, Gregory; Lednev, Igor K

    2016-07-01

    Hair and fibers are common forms of trace evidence found at crime scenes. The current methodology of microscopic examination of potential hair evidence is absent of statistical measures of performance, and examiner results for identification can be subjective. Here, attenuated total reflection (ATR) Fourier transform-infrared (FT-IR) spectroscopy was used to analyze synthetic fibers and natural hairs of human, cat, and dog origin. Chemometric analysis was used to differentiate hair spectra from the three different species, and to predict unknown hairs to their proper species class, with a high degree of certainty. A species-specific partial least squares discriminant analysis (PLSDA) model was constructed to discriminate human hair from cat and dog hairs. This model was successful in distinguishing between the three classes and, more importantly, all human samples were correctly predicted as human. An external validation resulted in zero false positive and false negative assignments for the human class. From a forensic perspective, this technique would be complementary to microscopic hair examination, and in no way replace it. As such, this methodology is able to provide a statistical measure of confidence to the identification of a sample of human, cat, and dog hair, which was called for in the 2009 National Academy of Sciences report. More importantly, this approach is non-destructive, rapid, can provide reliable results, and requires no sample preparation, making it of ample importance to the field of forensic science. © The Author(s) 2016.

  4. Cilia-driven fluid flow as an epigenetic cue for otolith biomineralization on sensory hair cells of the inner ear.

    Science.gov (United States)

    Yu, Xianwen; Lau, Doreen; Ng, Chee Peng; Roy, Sudipto

    2011-02-01

    Ciliary motility is necessary for many developmental and physiological processes in animals. In zebrafish, motile cilia are thought to be required for the deposition of otoliths, which comprise crystals of protein and calcium carbonate, on hair cells of the inner ear. The identity of the motile cilia and their role in otolith biogenesis, however, remain controversial. Here, we show that the ear vesicle differentiates numerous motile cilia, the spatial distribution of which changes as a function of the expression pattern of the ciliogenic gene foxj1b. By contrast, the hair cells develop immotile kinocilia that serve as static tethers for otolith crystallization. In ears devoid of all cilia, otoliths can form but they are of irregular shapes and sizes and appear to attach instead to the hair cell apical membranes. Moreover, overproduction of motile cilia also disrupts otolith deposition through sustained agitation of the precursor particles. Therefore, the correct spatial and temporal distribution of the motile cilia is crucial for proper otolith formation. Our findings support the view that the hair cells express a binding factor for the otolith precursors, while the motile cilia ensure that the precursors do not sediment prematurely and are efficiently directed towards the hair cells. We also provide evidence that the kinocilia are modified motile cilia that depend on Foxj1b for their differentiation. We propose that in hair cells, a Foxj1b-dependent motile ciliogenic program is altered by the proneural Atoh proteins to promote the differentiation of immotile kinocilia.

  5. Continuous Hair Cell Turnover in the Inner Ear Vestibular Organs of a Mammal, the Daubenton's Bat (Myotis daubentonii)

    Science.gov (United States)

    Kirkegaard, M.; Jørgensen, J. M.

    In both humans and mice the number of hair cells in the inner ear sensory epithelia declines with age, indicating cell death (Park et al. 1987; Rosenhall 1973). However, recent reports demonstrate the ability of the vestibular sensory epithelia to regenerate after injury (Forge et al. 1993, 1998; Kuntz and Oesterle 1998; Li and Forge 1997; Rubel et al. 1995; Tanyeri et al. 1995). Still, a continuous hair cell turnover in the vestibular epithelia has not previously been demonstrated in mature mammals. Bats are the only flying mammals, and they are known to live to a higher age than animals of equal size. The maximum age of many species is 20years, with average lifespans of 4-6years (Schober and Grimmberger 1989). Further, the young are fully developed and able to fly at the age of 2months, and thus the vestibular organs are thought to be differentiated at that age. Consequently, long-lived mammals such as bats might compensate for the loss of hair cells by producing new hair cells in their postembryonic life. Here we show that the utricular macula of adult Daubenton's bats (more than 6months old) contains innervated immature hair cells as well as apoptotic hair cells, which strongly indicates a continuous turnover of hair cells, as previously demonstrated in birds.

  6. Coenzyme Q10 protects hair cells against aminoglycoside.

    Directory of Open Access Journals (Sweden)

    Kazuma Sugahara

    Full Text Available It is well known that the production of free radicals is associated with sensory cell death induced by an aminoglycoside. Many researchers have reported that antioxidant reagents protect sensory cells in the inner ear, and coenzyme Q10 (CoQ10 is an antioxidant that is consumed as a health food in many countries. The purpose of this study was to investigate the role of CoQ10 in mammalian vestibular hair cell death induced by aminoglycoside. Cultured utricles of CBA/CaN mice were divided into three groups (control group, neomycin group, and neomycin + CoQ10 group. In the neomycin group, utricles were cultured with neomycin (1 mM to induce hair cell death. In the neomycin + CoQ10 group, utricles were cultured with neomycin and water-soluble CoQ10 (30-0.3 µM. Twenty-four hours after exposure to neomycin, the cultured tissues were fixed, and vestibular hair cells were labeled using an anti-calmodulin antibody. Significantly more hair cells survived in the neomycin + CoQ10 group than in the neomycin group. These data indicate that CoQ10 protects sensory hair cells against neomycin-induced death in the mammalian vestibular epithelium; therefore, CoQ10 may be useful as a protective drug in the inner ear.

  7. Melatonin mitigates neomycin-induced hair cell injury in zebrafish.

    Science.gov (United States)

    Oh, Kyoung Ho; Rah, Yoon Chan; Hwang, Kyu Ho; Lee, Seung Hoon; Kwon, Soon Young; Cha, Jae Hyung; Choi, June

    2017-10-01

    Ototoxicity due to medications, such as aminoglycosides, is irreversible, and free radicals in the inner ear are assumed to play a major role. Because melatonin has an antioxidant property, we hypothesize that it might mitigate hair cell injury by aminoglycosides. The objective of this study was to evaluate whether melatonin has an alleviative effect on neomycin-induced hair cell injury in zebrafish (Danio rerio). Various concentrations of melatonin were administered to 5-day post-fertilization zebrafish treated with 125 μM neomycin for 1 h. Surviving hair cells within four neuromasts were compared with that of a control group. Apoptosis was assessed via terminal deoxynucleotidyl transferase dUTP nick-end labeling assay. The changes of ultrastructure were confirmed using a scanning electron microscope. Melatonin alleviated neomycin-induced hair cell injury in neuromasts (neomycin + melatonin 100 μM: 13.88 ± 0.91 cells, neomycin only: 7.85 ± 0.90 cells; n = 10, p melatonin for 1 h in SEM findings. Melatonin is effective in alleviating aminoglycoside-induced hair cell injury in zebrafish. The results of this study demonstrated that melatonin has the potential to reduce apoptosis induced by aminoglycosides in zebrafish.

  8. The Effects of Urethane on Rat Outer Hair Cells

    Directory of Open Access Journals (Sweden)

    Mingyu Fu

    2016-01-01

    Full Text Available The cochlea converts sound vibration into electrical impulses and amplifies the low-level sound signal. Urethane, a widely used anesthetic in animal research, has been shown to reduce the neural responses to auditory stimuli. However, the effects of urethane on cochlea, especially on the function of outer hair cells, remain largely unknown. In the present study, we compared the cochlear microphonic responses between awake and urethane-anesthetized rats. The results revealed that the amplitude of the cochlear microphonic was decreased by urethane, resulting in an increase in the threshold at all of the sound frequencies examined. To deduce the possible mechanism underlying the urethane-induced decrease in cochlear sensitivity, we examined the electrical response properties of isolated outer hair cells using whole-cell patch-clamp recording. We found that urethane hyperpolarizes the outer hair cell membrane potential in a dose-dependent manner and elicits larger outward current. This urethane-induced outward current was blocked by strychnine, an antagonist of the α9 subunit of the nicotinic acetylcholine receptor. Meanwhile, the function of the outer hair cell motor protein, prestin, was not affected. These results suggest that urethane anesthesia is expected to decrease the responses of outer hair cells, whereas the frequency selectivity of cochlea remains unchanged.

  9. Protein biosynthesis in cultured human hair follicle cells.

    Science.gov (United States)

    Weterings, P J; Vermorken, A J; Bloemendal, H

    1980-10-31

    A new technique has been used for culturing human keratinocytes. The cells grow on the basement membrane-like capsules of bovine lenses. Lens cells were removed from the capsules by rigid trypsinization. In order to exclude any contamination with remaining living cells the isolated capsules were irradiated with X-rays at a dose of 10,000 rad. In this way human epithelial cells can be brought in culture from individual hair follicles. Since feeder cells are not used in this culture technique, the biosynthesis of keratinocyte proteins can be studied in these cultures. The newly synthesized proteins can be separated into a water-soluble, a urea-soluble, and a urea-insoluble fraction. Product analysis has been performed on the first two fractions revealing protein patterns identical to those of intact hair follicles. Product analysis of the urea-soluble fractions of microdissected hair follicles shows that the protein pattern of the cultured keratinocytes resembles the protein pattern of the hair follicle sheath. Studies on the metabolism of benzo(a)pyrene revealed that the enzyme aryl hydrocarbon hydroxylase (AHH) is present in cultured hair follicle cells. A possible use of our culture system for eventual detection of inherited predisposition for smoking-dependent lung cancer is discussed.

  10. Characterization of Lgr6+ Cells as an Enriched Population of Hair Cell Progenitors Compared to Lgr5+ Cells for Hair Cell Generation in the Neonatal Mouse Cochlea

    Directory of Open Access Journals (Sweden)

    Yanping Zhang

    2018-05-01

    Full Text Available Hair cell (HC loss is irreversible because only very limited HC regeneration has been observed in the adult mammalian cochlea. Wnt/β-catenin signaling regulates prosensory cell proliferation and differentiation during cochlear development, and Wnt activation promotes the proliferation of Lgr5+ cochlear HC progenitors in newborn mice. Similar to Lgr5, Lgr6 is also a Wnt downstream target gene. Lgr6 is reported to be present in adult stem cells in the skin, nail, tongue, lung, and mammary gland, and this protein is very important for adult stem cell maintenance in rapidly proliferating organs. Our previous studies showed that Lgr6+ cells are a subpopulation of Lgr5+ progenitor cells and that both Lgr6+ and Lgr5+ progenitors can generate Myosin7a+ HCs in vitro. Thus we hypothesized that Lgr6+ cells are an enriched population of cochlear progenitor cells. However, the detailed distinctions between the Lgr5+ and Lgr6+ progenitors are unclear. Here, we systematically compared the proliferation, HC differentiation, and detailed transcriptome expression profiles of these two progenitor populations. We found that the same number of isolated Lgr6+ progenitors generated significantly more Myosin7a+ HCs compared to Lgr5+ progenitors; however, Lgr5+ progenitors formed more epithelial colonies and more spheres than Lgr6+ progenitors in vitro. Using RNA-Seq, we compared the transcriptome differences between Lgr5+ and Lgr6+ progenitors and identified a list of significantly differential expressed genes that might regulate the proliferation and differentiation of these HC progenitors, including 4 cell cycle genes, 9 cell signaling pathway genes, and 54 transcription factors. In conclusion, we demonstrate that Lgr6+ progenitors are an enriched population of inner ear progenitors that generate more HCs compared to Lgr5+ progenitors in the newborn mouse cochlea, and the our research provides a series of genes that might regulate the proliferation of progenitors

  11. Hair Follicle: A Novel Source of Multipotent Stem Cells for Tissue Engineering and Regenerative Medicine

    Science.gov (United States)

    Mistriotis, Panagiotis

    2013-01-01

    The adult body harbors powerful reservoirs of stem cells that enable tissue regeneration under homeostatic conditions or in response to disease or injury. The hair follicle (HF) is a readily accessible mini organ within the skin and contains stem cells from diverse developmental origins that were shown to have surprisingly broad differentiation potential. In this review, we discuss the biology of the HF with particular emphasis on the various stem cell populations residing within the tissue. We summarize the existing knowledge on putative HF stem cell markers, the differentiation potential, and technologies to isolate and expand distinct stem cell populations. We also discuss the potential of HF stem cells for drug and gene delivery, tissue engineering, and regenerative medicine. We propose that the abundance of stem cells with broad differentiation potential and the ease of accessibility makes the HF an ideal source of stem cells for gene and cell therapies. PMID:23157470

  12. Usher protein functions in hair cells and photoreceptors.

    Science.gov (United States)

    Cosgrove, Dominic; Zallocchi, Marisa

    2014-01-01

    The 10 different genes associated with the deaf/blind disorder, Usher syndrome, encode a number of structurally and functionally distinct proteins, most expressed as multiple isoforms/protein variants. Functional characterization of these proteins suggests a role in stereocilia development in cochlear hair cells, likely owing to adhesive interactions in hair bundles. In mature hair cells, homodimers of the Usher cadherins, cadherin 23 and protocadherin 15, interact to form a structural fiber, the tip link, and the linkages that anchor the taller stereocilia's actin cytoskeleton core to the shorter adjacent stereocilia and the elusive mechanotransduction channels, explaining the deafness phenotype when these molecular interactions are perturbed. The conundrum is that photoreceptors lack a synonymous mechanotransduction apparatus, and so a common theory for Usher protein function in the two neurosensory cell types affected in Usher syndrome is lacking. Recent evidence linking photoreceptor cell dysfunction in the shaker 1 mouse model for Usher syndrome to light-induced protein translocation defects, combined with localization of an Usher protein interactome at the periciliary region of the photoreceptors suggests Usher proteins might regulate protein trafficking between the inner and outer segments of photoreceptors. A distinct Usher protein complex is trafficked to the ribbon synapses of hair cells, and synaptic defects have been reported in Usher mutants in both hair cells and photoreceptors. This review aims to clarify what is known about Usher protein function at the synaptic and apical poles of hair cells and photoreceptors and the prospects for identifying a unifying pathobiological mechanism to explain deaf/blindness in Usher syndrome. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. A Review of Gene Delivery and Stem Cell Based Therapies for Regenerating Inner Ear Hair Cells

    OpenAIRE

    Michael S. Detamore; Keerthana Devarajan; Hinrich Staecker

    2011-01-01

    Sensory neural hearing loss and vestibular dysfunction have become the most common forms of sensory defects, affecting millions of people worldwide. Developing effective therapies to restore hearing loss is challenging, owing to the limited regenerative capacity of the inner ear hair cells. With recent advances in understanding the developmental biology of mammalian and non-mammalian hair cells a variety of strategies have emerged to restore lost hair cells are being developed. Two predominan...

  14. Lgr5 marks cycling, yet long-lived, hair follicle stem cells.

    NARCIS (Netherlands)

    Jaks, V.; Barker, N.; Kasper, M.; van Es, J.H.; Snippert, H.J.G.; Clevers, H.; Toftgard, R.

    2008-01-01

    In mouse hair follicles, a group of quiescent cells in the bulge is believed to have stem cell activity. Lgr5, a marker of intestinal stem cells, is expressed in actively cycling cells in the bulge and secondary germ of telogen hair follicles and in the lower outer root sheath of anagen hair

  15. Maintained expression of the planar cell polarity molecule Vangl2 and reformation of hair cell orientation in the regenerating inner ear.

    Science.gov (United States)

    Warchol, Mark E; Montcouquiol, Mireille

    2010-09-01

    The avian inner ear possesses a remarkable ability to regenerate sensory hair cells after ototoxic injury. Regenerated hair cells possess phenotypes and innervation that are similar to those found in the undamaged ear, but little is known about the signaling pathways that guide hair cell differentiation during the regenerative process. The aim of the present study was to examine the factors that specify the orientation of hair cell stereocilia bundles during regeneration. Using organ cultures of the chick utricle, we show that hair cells are properly oriented after having regenerated entirely in vitro and that orientation is not affected by surgical removal of the striolar reversal zone. These results suggest that the orientation of regenerating stereocilia is not guided by the release of a diffusible morphogen from the striolar reversal zone but is specified locally within the regenerating sensory organ. In order to determine the nature of the reorientation cues, we examined the expression patterns of the core planar cell polarity molecule Vangl2 in the normal and regenerating utricle. We found that Vangl2 is asymmetrically expressed on cells within the sensory epithelium and that this expression pattern is maintained after ototoxic injury and throughout regeneration. Notably, treatment with a small molecule inhibitor of c-Jun-N-terminal kinase disrupted the orientation of regenerated hair cells. Both of these results are consistent with the hypothesis that noncanonical Wnt signaling guides hair cell orientation during regeneration.

  16. A Review of Gene Delivery and Stem Cell Based Therapies for Regenerating Inner Ear Hair Cells

    Directory of Open Access Journals (Sweden)

    Michael S. Detamore

    2011-09-01

    Full Text Available Sensory neural hearing loss and vestibular dysfunction have become the most common forms of sensory defects, affecting millions of people worldwide. Developing effective therapies to restore hearing loss is challenging, owing to the limited regenerative capacity of the inner ear hair cells. With recent advances in understanding the developmental biology of mammalian and non-mammalian hair cells a variety of strategies have emerged to restore lost hair cells are being developed. Two predominant strategies have developed to restore hair cells: transfer of genes responsible for hair cell genesis and replacement of missing cells via transfer of stem cells. In this review article, we evaluate the use of several genes involved in hair cell regeneration, the advantages and disadvantages of the different viral vectors employed in inner ear gene delivery and the insights gained from the use of embryonic, adult and induced pluripotent stem cells in generating inner ear hair cells. Understanding the role of genes, vectors and stem cells in therapeutic strategies led us to explore potential solutions to overcome the limitations associated with their use in hair cell regeneration.

  17. A review of gene delivery and stem cell based therapies for regenerating inner ear hair cells.

    Science.gov (United States)

    Devarajan, Keerthana; Staecker, Hinrich; Detamore, Michael S

    2011-09-13

    Sensory neural hearing loss and vestibular dysfunction have become the most common forms of sensory defects, affecting millions of people worldwide. Developing effective therapies to restore hearing loss is challenging, owing to the limited regenerative capacity of the inner ear hair cells. With recent advances in understanding the developmental biology of mammalian and non-mammalian hair cells a variety of strategies have emerged to restore lost hair cells are being developed. Two predominant strategies have developed to restore hair cells: transfer of genes responsible for hair cell genesis and replacement of missing cells via transfer of stem cells. In this review article, we evaluate the use of several genes involved in hair cell regeneration, the advantages and disadvantages of the different viral vectors employed in inner ear gene delivery and the insights gained from the use of embryonic, adult and induced pluripotent stem cells in generating inner ear hair cells. Understanding the role of genes, vectors and stem cells in therapeutic strategies led us to explore potential solutions to overcome the limitations associated with their use in hair cell regeneration.

  18. Activation of CHK1 in Supporting Cells Indirectly Promotes Hair Cell Survival

    Directory of Open Access Journals (Sweden)

    Azadeh Jadali

    2017-05-01

    Full Text Available The sensory hair cells of the inner ear are exquisitely sensitive to ototoxic insults. Loss of hair cells after exposure to ototoxic agents causes hearing loss. Chemotherapeutic agents such as cisplatin causes hair cell loss. Cisplatin forms DNA mono-adducts as well as intra- and inter-strand DNA crosslinks. DNA cisplatin adducts are repaired through the DNA damage response. The decision between cell survival and cell death following DNA damage rests on factors that are involved in determining damage tolerance, cell survival and apoptosis. Cisplatin damage on hair cells has been the main focus of many ototoxic studies, yet the effect of cisplatin on supporting cells has been largely ignored. In this study, the effects of DNA damage response in cochlear supporting cells were interrogated. Supporting cells play a major role in the development, maintenance and oto-protection of hair cells. Loss of supporting cells may indirectly affect hair cell survival or maintenance. Activation of the Phosphoinositide 3-Kinase (PI3K signaling was previously shown to promote hair cell survival. To test whether activating PI3K signaling promotes supporting cell survival after cisplatin damage, cochlear explants from the neural subset (NS Cre Pten conditional knockout mice were employed. Deletion of Phosphatase and Tensin Homolog (PTEN activates PI3K signaling in multiple cell types within the cochlea. Supporting cells lacking PTEN showed increased cell survival after cisplatin damage. Supporting cells lacking PTEN also showed increased phosphorylation of Checkpoint Kinase 1 (CHK1 levels after cisplatin damage. Nearest neighbor analysis showed increased numbers of supporting cells with activated PI3K signaling in close proximity to surviving hair cells in cisplatin damaged cochleae. We propose that increased PI3K signaling promotes supporting cell survival through phosphorylation of CHK1 and increased survival of supporting cells indirectly increases hair cell

  19. Heat pulse excitability of vestibular hair cells and afferent neurons

    Science.gov (United States)

    Brichta, Alan M.; Tabatabaee, Hessam; Boutros, Peter J.; Ahn, JoongHo; Della Santina, Charles C.; Poppi, Lauren A.; Lim, Rebecca

    2016-01-01

    In the present study we combined electrophysiology with optical heat pulse stimuli to examine thermodynamics of membrane electrical excitability in mammalian vestibular hair cells and afferent neurons. We recorded whole cell currents in mammalian type II vestibular hair cells using an excised preparation (mouse) and action potentials (APs) in afferent neurons in vivo (chinchilla) in response to optical heat pulses applied to the crista (ΔT ≈ 0.25°C per pulse). Afferent spike trains evoked by heat pulse stimuli were diverse and included asynchronous inhibition, asynchronous excitation, and/or phase-locked APs synchronized to each infrared heat pulse. Thermal responses of membrane currents responsible for APs in ganglion neurons were strictly excitatory, with Q10 ≈ 2. In contrast, hair cells responded with a mix of excitatory and inhibitory currents. Excitatory hair cell membrane currents included a thermoelectric capacitive current proportional to the rate of temperature rise (dT/dt) and an inward conduction current driven by ΔT. An iberiotoxin-sensitive inhibitory conduction current was also evoked by ΔT, rising in heat pulse excitability in vestibular sensory organs and provide quantitative methods for rational application of optical heat pulses to examine protein biophysics and manipulate cellular excitability. PMID:27226448

  20. Heat pulse excitability of vestibular hair cells and afferent neurons.

    Science.gov (United States)

    Rabbitt, Richard D; Brichta, Alan M; Tabatabaee, Hessam; Boutros, Peter J; Ahn, JoongHo; Della Santina, Charles C; Poppi, Lauren A; Lim, Rebecca

    2016-08-01

    In the present study we combined electrophysiology with optical heat pulse stimuli to examine thermodynamics of membrane electrical excitability in mammalian vestibular hair cells and afferent neurons. We recorded whole cell currents in mammalian type II vestibular hair cells using an excised preparation (mouse) and action potentials (APs) in afferent neurons in vivo (chinchilla) in response to optical heat pulses applied to the crista (ΔT ≈ 0.25°C per pulse). Afferent spike trains evoked by heat pulse stimuli were diverse and included asynchronous inhibition, asynchronous excitation, and/or phase-locked APs synchronized to each infrared heat pulse. Thermal responses of membrane currents responsible for APs in ganglion neurons were strictly excitatory, with Q10 ≈ 2. In contrast, hair cells responded with a mix of excitatory and inhibitory currents. Excitatory hair cell membrane currents included a thermoelectric capacitive current proportional to the rate of temperature rise (dT/dt) and an inward conduction current driven by ΔT An iberiotoxin-sensitive inhibitory conduction current was also evoked by ΔT, rising in protein biophysics and manipulate cellular excitability. Copyright © 2016 the American Physiological Society.

  1. An Analogue VLSI Implementation of the Meddis Inner Hair Cell Model

    Science.gov (United States)

    McEwan, Alistair; van Schaik, André

    2003-12-01

    The Meddis inner hair cell model is a widely accepted, but computationally intensive computer model of mammalian inner hair cell function. We have produced an analogue VLSI implementation of this model that operates in real time in the current domain by using translinear and log-domain circuits. The circuit has been fabricated on a chip and tested against the Meddis model for (a) rate level functions for onset and steady-state response, (b) recovery after masking, (c) additivity, (d) two-component adaptation, (e) phase locking, (f) recovery of spontaneous activity, and (g) computational efficiency. The advantage of this circuit, over other electronic inner hair cell models, is its nearly exact implementation of the Meddis model which can be tuned to behave similarly to the biological inner hair cell. This has important implications on our ability to simulate the auditory system in real time. Furthermore, the technique of mapping a mathematical model of first-order differential equations to a circuit of log-domain filters allows us to implement real-time neuromorphic signal processors for a host of models using the same approach.

  2. An Analogue VLSI Implementation of the Meddis Inner Hair Cell Model

    Directory of Open Access Journals (Sweden)

    Alistair McEwan

    2003-06-01

    Full Text Available The Meddis inner hair cell model is a widely accepted, but computationally intensive computer model of mammalian inner hair cell function. We have produced an analogue VLSI implementation of this model that operates in real time in the current domain by using translinear and log-domain circuits. The circuit has been fabricated on a chip and tested against the Meddis model for (a rate level functions for onset and steady-state response, (b recovery after masking, (c additivity, (d two-component adaptation, (e phase locking, (f recovery of spontaneous activity, and (g computational efficiency. The advantage of this circuit, over other electronic inner hair cell models, is its nearly exact implementation of the Meddis model which can be tuned to behave similarly to the biological inner hair cell. This has important implications on our ability to simulate the auditory system in real time. Furthermore, the technique of mapping a mathematical model of first-order differential equations to a circuit of log-domain filters allows us to implement real-time neuromorphic signal processors for a host of models using the same approach.

  3. XIRP2, an Actin-Binding Protein Essential for Inner Ear Hair-Cell Stereocilia

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    Déborah I. Scheffer

    2015-03-01

    Full Text Available Hair cells of the inner ear are mechanoreceptors for hearing and balance, and proteins highly enriched in hair cells may have specific roles in the development and maintenance of the mechanotransduction apparatus. We identified XIRP2/mXinβ as an enriched protein likely to be essential for hair cells. We found that different isoforms of this protein are expressed and differentially located: short splice forms (also called XEPLIN are targeted more to stereocilia, whereas two long isoforms containing a XIN-repeat domain are in both stereocilia and cuticular plates. Mice lacking the Xirp2 gene developed normal stereocilia bundles, but these degenerated with time: stereocilia were lost and long membranous protrusions emanated from the nearby apical surfaces. At an ultrastructural level, the paracrystalline actin filaments became disorganized. XIRP2 is apparently involved in the maintenance of actin structures in stereocilia and cuticular plates of hair cells, and perhaps in other organs where it is expressed.

  4. A method for culturing human hair follicle cells.

    Science.gov (United States)

    Weterings, P J; Vermorken, A J; Bloemendal, H

    1981-01-01

    For the first time a method for culturing human hair follicle cells is described. The bovine eye lens capsule, a basement membrane-like structure, is used as the substrate for the cultures. In a culture medium supplemented with hydrocortisone and insulin about 70% of the original follicles will form growing colonies of diploid keratinocytes.

  5. Investigation of hair dye deposition, hair color loss, and hair damage during multiple oxidative dyeing and shampooing cycles.

    Science.gov (United States)

    Zhang, Guojin; McMullen, Roger L; Kulcsar, Lidia

    2016-01-01

    Color fastness is a major concern for consumers and manufacturers of oxidative hair dye products. Hair dye loss results from multiple wash cycles in which the hair dye is dissolved by water and leaches from the hair shaft. In this study, we carried out a series of measurements to help us better understand the kinetics of the leaching process and pathways associated with its escape from the fiber. Hair dye leaching kinetics was measured by suspending hair in a dissolution apparatus and monitoring the dye concentration in solution (leached dye) with an ultraviolet-visible spectrophotometer. The physical state of dye deposited in hair fibers was evaluated by a reflectance light microscopy technique, based on image stacking, allowing enhanced depth of field imaging. The dye distribution within the fiber was monitored by infrared spectroscopic imaging of hair fiber cross sections. Damage to the ultrafine structure of the hair cuticle (surface, endocuticle, and cell membrane complex) and cortex (cell membrane complex) was determined in hair cross sections and on the hair fiber surface with atomic force microscopy. Using differential scanning calorimetry, we investigated how consecutive coloring and leaching processes affect the internal proteins of hair. Further, to probe the surface properties of hair we utilized contact angle measurements. This study was conducted on both pigmented and nonpigmented hair to gain insight into the influence of melanin on the hair dye deposition and leaching processes. Both types of hair were colored utilizing a commercial oxidative hair dye product based on pyrazole chemistry.

  6. Efferent control of the electrical and mechanical properties of hair cells in the bullfrog's sacculus.

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    Manuel Castellano-Muñoz

    2010-10-01

    Full Text Available Hair cells in the auditory, vestibular, and lateral-line systems respond to mechanical stimulation and transmit information to afferent nerve fibers. The sensitivity of mechanoelectrical transduction is modulated by the efferent pathway, whose activity usually reduces the responsiveness of hair cells. The basis of this effect remains unknown.We employed immunocytological, electrophysiological, and micromechanical approaches to characterize the anatomy of efferent innervation and the effect of efferent activity on the electrical and mechanical properties of hair cells in the bullfrog's sacculus. We found that efferent fibers form extensive synaptic terminals on all macular and extramacular hair cells. Macular hair cells expressing the Ca(2+-buffering protein calretinin contain half as many synaptic ribbons and are innervated by twice as many efferent terminals as calretinin-negative hair cells. Efferent activity elicits inhibitory postsynaptic potentials in hair cells and thus inhibits their electrical resonance. In hair cells that exhibit spiking activity, efferent stimulation suppresses the generation of action potentials. Finally, efferent activity triggers a displacement of the hair bundle's resting position.The hair cells of the bullfrog's sacculus receive a rich efferent innervation with the heaviest projection to calretinin-containing cells. Stimulation of efferent axons desensitizes the hair cells and suppresses their spiking activity. Although efferent activation influences mechanoelectrical transduction, the mechanical effects on hair bundles are inconsistent.

  7. Stem cell plasticity enables hair regeneration following Lgr5+ cell loss.

    Science.gov (United States)

    Hoeck, Joerg D; Biehs, Brian; Kurtova, Antonina V; Kljavin, Noelyn M; de Sousa E Melo, Felipe; Alicke, Bruno; Koeppen, Hartmut; Modrusan, Zora; Piskol, Robert; de Sauvage, Frederic J

    2017-06-01

    Under injury conditions, dedicated stem cell populations govern tissue regeneration. However, the molecular mechanisms that induce stem cell regeneration and enable plasticity are poorly understood. Here, we investigate stem cell recovery in the context of the hair follicle to understand how two molecularly distinct stem cell populations are integrated. Utilizing diphtheria-toxin-mediated cell ablation of Lgr5 + (leucine-rich repeat-containing G-protein-coupled receptor 5) stem cells, we show that killing of Lgr5 + cells in mice abrogates hair regeneration but this is reversible. During recovery, CD34 + (CD34 antigen) stem cells activate inflammatory response programs and start dividing. Pharmacological attenuation of inflammation inhibits CD34 + cell proliferation. Subsequently, the Wnt pathway controls the recovery of Lgr5 + cells and inhibition of Wnt signalling prevents Lgr5 + cell and hair germ recovery. Thus, our study uncovers a compensatory relationship between two stem cell populations and the underlying molecular mechanisms that enable hair follicle regeneration.

  8. Hair cell regeneration in the bullfrog vestibular otolith organs following aminoglycoside toxicity

    Science.gov (United States)

    Baird, Richard A.; Torres, M. A.; Schuff, N. R.

    1994-01-01

    Adult bullfrogs were given single intraotic injections of the aminoglycoside antibiotic gentamicin sulfate and sacrificed at postinjection times ranging from 0.5 to 9 days. The saccular and utricular maculae of normal and injected animals were examined in wholemount and cross-section. Intraotic 200 (mu) M gentamicin concentrations resulted in the uniform destruction of the hair bundles and, at later times, the cell bodies of saccular hair cells. In the utriculus, striolar hair cells were selectively damaged while extrastriolar hair cells were relatively unaffected. Regenerating hair cells, identified in sectioned material by their small cell bodies and short, well-formed hair bundles, were seen in the saccular and utricular maculae as early as 24-48 h postinjection. Immature versions of mature hair cell types in both otolith organs were recognized by the presence of absence of a bulbed kinocilia and the relative lengths of their kinocilia and longest sterocilia. Utricular hair cell types with kinocilia longer than their longest stereocilia were observed at earlier times than hair cell types with shorter kinocilia. In the same sacculus, the hair bundles of gentamicin-treated animals, even at 9 days postinjection, were significantly smaller than those of normal animals. The hair bundles of utricular hair cells, on the other hand, reached full maturity within the same time period.

  9. Enhancement of cell wall protein SRPP expression during emergent root hair development in Arabidopsis.

    Science.gov (United States)

    Uno, Hiroshi; Tanaka-Takada, Natsuki; Sato, Ryosuke; Maeshima, Masayoshi

    2017-10-03

    SRPP is a protein expressed in seeds and root hairs and is significantly induced in root hairs under phosphate (Pi)-deficient conditions. Root hairs in the knockout mutant srpp-1 display defects, i.e., suppression of cell growth and cell death. Here, we analyzed the expression profile of SRPP during cell elongation of root hairs and compared the transcript levels in several mutants with short root hairs. The mRNA level was increased in wild-type plants and decreased in mutants with short root hairs. Induction of SRPP expression by Pi starvation occurred one or two days later than induction of Pi-deficient sensitive genes, such as PHT1 and PHF1. These results indicate that the expression of SRPP is coordinated with root hair elongation. We hypothesize that SRPP is essential for structural robustness of the cell walls of root hairs.

  10. Guided genetic screen to identify genes essential in the regeneration of hair cells and other tissues.

    Science.gov (United States)

    Pei, Wuhong; Xu, Lisha; Huang, Sunny C; Pettie, Kade; Idol, Jennifer; Rissone, Alberto; Jimenez, Erin; Sinclair, Jason W; Slevin, Claire; Varshney, Gaurav K; Jones, MaryPat; Carrington, Blake; Bishop, Kevin; Huang, Haigen; Sood, Raman; Lin, Shuo; Burgess, Shawn M

    2018-01-01

    Regenerative medicine holds great promise for both degenerative diseases and traumatic tissue injury which represent significant challenges to the health care system. Hearing loss, which affects hundreds of millions of people worldwide, is caused primarily by a permanent loss of the mechanosensory receptors of the inner ear known as hair cells. This failure to regenerate hair cells after loss is limited to mammals, while all other non-mammalian vertebrates tested were able to completely regenerate these mechanosensory receptors after injury. To understand the mechanism of hair cell regeneration and its association with regeneration of other tissues, we performed a guided mutagenesis screen using zebrafish lateral line hair cells as a screening platform to identify genes that are essential for hair cell regeneration, and further investigated how genes essential for hair cell regeneration were involved in the regeneration of other tissues. We created genetic mutations either by retroviral insertion or CRISPR/Cas9 approaches, and developed a high-throughput screening pipeline for analyzing hair cell development and regeneration. We screened 254 gene mutations and identified 7 genes specifically affecting hair cell regeneration. These hair cell regeneration genes fell into distinct and somewhat surprising functional categories. By examining the regeneration of caudal fin and liver, we found these hair cell regeneration genes often also affected other types of tissue regeneration. Therefore, our results demonstrate guided screening is an effective approach to discover regeneration candidates, and hair cell regeneration is associated with other tissue regeneration.

  11. Static length changes of cochlear outer hair cells can tune low-frequency hearing.

    Directory of Open Access Journals (Sweden)

    Nikola Ciganović

    2018-01-01

    Full Text Available The cochlea not only transduces sound-induced vibration into neural spikes, it also amplifies weak sound to boost its detection. Actuators of this active process are sensory outer hair cells in the organ of Corti, whereas the inner hair cells transduce the resulting motion into electric signals that propagate via the auditory nerve to the brain. However, how the outer hair cells modulate the stimulus to the inner hair cells remains unclear. Here, we combine theoretical modeling and experimental measurements near the cochlear apex to study the way in which length changes of the outer hair cells deform the organ of Corti. We develop a geometry-based kinematic model of the apical organ of Corti that reproduces salient, yet counter-intuitive features of the organ's motion. Our analysis further uncovers a mechanism by which a static length change of the outer hair cells can sensitively tune the signal transmitted to the sensory inner hair cells. When the outer hair cells are in an elongated state, stimulation of inner hair cells is largely inhibited, whereas outer hair cell contraction leads to a substantial enhancement of sound-evoked motion near the hair bundles. This novel mechanism for regulating the sensitivity of the hearing organ applies to the low frequencies that are most important for the perception of speech and music. We suggest that the proposed mechanism might underlie frequency discrimination at low auditory frequencies, as well as our ability to selectively attend auditory signals in noisy surroundings.

  12. Hair cell regeneration in sensory epithelia from the inner ear of a urodele amphibian.

    Science.gov (United States)

    Taylor, Ruth R; Forge, Andrew

    2005-03-28

    The capacity of urodele amphibians to regenerate a variety of body parts is providing insight into mechanisms of tissue regeneration in vertebrates. In this study the ability of the newt, Notophthalmus viridescens, to regenerate inner ear hair cells in vitro was examined. Intact otic capsules were maintained in organotypic culture. Incubation in 2 mM gentamicin for 48 hours resulted in ablation of all hair cells from the saccular maculae. Thus, any hair cell recovery was not due to repair of damaged hair cells. Immature hair cells were subsequently observed at approximately 12 days posttreatment. Their number increased over the following 7-14 days to reach approximately 30% of the normal number. Following incubation of damaged tissue with bromodeoxyuridine (BrdU), labeled nuclei were confined strictly within regions of hair cell loss, indicating that supporting cells entered S-phase. Double labeling of tissue with two different hair cell markers and three different antibodies to BrdU in various combinations, however, all showed that the nuclei of cells that labeled with hair cell markers did not label for BrdU. This suggested that the new hair cells were not derived from those cells that had undergone mitosis. When mitosis was blocked with aphidicolin, new hair cells were still generated. The results suggest that direct phenotypic conversion of supporting cells into hair cells without an intervening mitotic event is a major mechanism of hair cell regeneration in the newt. A similar mechanism has been proposed for the hair cell recovery phenomenon observed in the vestibular organs of mammals. Copyright 2005 Wiley-Liss, Inc.

  13. The genetics of hair-cell function in zebrafish.

    Science.gov (United States)

    Nicolson, Teresa

    2017-09-01

    Our ears are remarkable sensory organs, providing the important senses of balance and hearing. The complex structure of the inner ear, or 'labyrinth', along with the assorted neuroepithelia, have evolved to detect head movements and sounds with impressive sensitivity. The rub is that the inner ear is highly vulnerable to genetic lesions and environmental insults. According to National Institute of Health estimates, hearing loss is one of the most commonly inherited or acquired sensorineural diseases. To understand the causes of deafness and balance disorders, it is imperative to understand the underlying biology of the inner ear, especially the inner workings of the sensory receptors. These receptors, which are termed hair cells, are particularly susceptible to genetic mutations - more than two dozen genes are associated with defects in this cell type in humans. Over the past decade, a substantial amount of progress has been made in working out the molecular basis of hair-cell function using vertebrate animal models. Given the transparency of the inner ear and the genetic tools that are available, zebrafish have become an increasingly popular animal model for the study of deafness and vestibular dysfunction. Mutagenesis screens for larval defects in hearing and balance have been fruitful in finding key components, many of which have been implicated in human deafness. This review will focus on the genes that are required for hair-cell function in zebrafish, with a particular emphasis on mechanotransduction. In addition, the generation of new tools available for the characterization of zebrafish hair-cell mutants will be discussed.

  14. Developing an active artificial hair cell using nonlinear feedback control

    Science.gov (United States)

    Joyce, Bryan S.; Tarazaga, Pablo A.

    2015-09-01

    The hair cells in the mammalian cochlea convert sound-induced vibrations into electrical signals. These cells have inspired a variety of artificial hair cells (AHCs) to serve as biologically inspired sound, fluid flow, and acceleration sensors and could one day replace damaged hair cells in humans. Most of these AHCs rely on passive transduction of stimulus while it is known that the biological cochlea employs active processes to amplify sound-induced vibrations and improve sound detection. In this work, an active AHC mimics the active, nonlinear behavior of the cochlea. The AHC consists of a piezoelectric bimorph beam subjected to a base excitation. A feedback control law is used to reduce the linear damping of the beam and introduce a cubic damping term which gives the AHC the desired nonlinear behavior. Model and experimental results show the AHC amplifies the response due to small base accelerations, has a higher frequency sensitivity than the passive system, and exhibits a compressive nonlinearity like that of the mammalian cochlea. This bio-inspired accelerometer could lead to new sensors with lower thresholds of detection, improved frequency sensitivities, and wider dynamic ranges.

  15. Inexhaustible hair-cell regeneration in young and aged zebrafish

    Directory of Open Access Journals (Sweden)

    Filipe Pinto-Teixeira

    2015-07-01

    Full Text Available Animals have evolved two general strategies to counter injury and maintain physiological function. The most prevalent is protection by isolating vital organs into body cavities. However, protection is not optimal for sensory systems because their external components need to be exposed to the environment to fulfill their receptive function. Thus, a common strategy to maintain sensory abilities against persistent environmental insult involves repair and regeneration. However, whether age or frequent injuries affect the regenerative capacity of sensory organs remains unknown. We have found that neuromasts of the zebrafish lateral line regenerate mechanosensory hair cells after recurrent severe injuries and in adulthood. Moreover, neuromasts can reverse transient imbalances of Notch signaling that result in defective organ proportions during repair. Our results reveal inextinguishable hair-cell regeneration in the lateral line, and suggest that the neuromast epithelium is formed by plastic territories that are maintained by continuous intercellular communication.

  16. Repair of traumatized mammalian hair cells via sea anemone repair proteins.

    Science.gov (United States)

    Tang, Pei-Ciao; Smith, Karen Müller; Watson, Glen M

    2016-08-01

    Mammalian hair cells possess only a limited ability to repair damage after trauma. In contrast, sea anemones show a marked capability to repair damaged hair bundles by means of secreted repair proteins (RPs). Previously, it was found that recovery of traumatized hair cells in blind cavefish was enhanced by anemone-derived RPs; therefore, the ability of anemone RPs to assist recovery of damaged hair cells in mammals was tested here. After a 1 h incubation in RP-enriched culture media, uptake of FM1-43 by experimentally traumatized murine cochlear hair cells was restored to levels comparable to those exhibited by healthy controls. In addition, RP-treated explants had significantly more normally structured hair bundles than time-matched traumatized control explants. Collectively, these results indicate that anemone-derived RPs assist in restoring normal function and structure of experimentally traumatized hair cells of the mouse cochlea. © 2016. Published by The Company of Biologists Ltd.

  17. Hair Follicle and Sebaceous Gland De Novo Regeneration With Cultured Epidermal Stem Cells and Skin-Derived Precursors.

    Science.gov (United States)

    Wang, Xiaoxiao; Wang, Xusheng; Liu, Jianjun; Cai, Ting; Guo, Ling; Wang, Shujuan; Wang, Jinmei; Cao, Yanpei; Ge, Jianfeng; Jiang, Yuyang; Tredget, Edward E; Cao, Mengjun; Wu, Yaojiong

    2016-12-01

    : Stem cell-based organ regeneration is purported to enable the replacement of impaired organs in the foreseeable future. Here, we demonstrated that a combination of cultured epidermal stem cells (Epi-SCs) derived from the epidermis and skin-derived precursors (SKPs) was capable of reconstituting functional hair follicles and sebaceous glands (SG). When Epi-SCs and SKPs were mixed in a hydrogel and implanted into an excisional wound in nude mice, the Epi-SCs formed de novo epidermis along with hair follicles, and SKPs contributed to dermal papilla in the neogenic hair follicles. Notably, a combination of culture-expanded Epi-SCs and SKPs derived from the adult human scalp were sufficient to generate hair follicles and hair. Bone morphogenetic protein 4, but not Wnts, sustained the expression of alkaline phosphatase in SKPs in vitro and the hair follicle-inductive property in vivo when SKPs were engrafted with neonatal epidermal cells into excisional wounds. In addition, Epi-SCs were capable of differentiating into sebocytes and formed de novo SGs, which excreted lipids as do normal SGs. Thus our results indicate that cultured Epi-SCs and SKPs are sufficient to generate de novo hair follicles and SGs, implying great potential to develop novel bioengineered skin substitutes with appendage genesis capacity. In postpartum humans, skin appendages lost in injury are not regenerated, despite the considerable achievement made in skin bioengineering. In this study, transplantation of a combination of culture-expanded epidermal stem cells and skin-derived progenitors from mice and adult humans led to de novo regeneration of functional hair follicles and sebaceous glands. The data provide transferable knowledge for the development of novel bioengineered skin substitutes with epidermal appendage regeneration capacity. ©AlphaMed Press.

  18. The electrical properties of auditory hair cells in the frog amphibian papilla.

    Science.gov (United States)

    Smotherman, M S; Narins, P M

    1999-07-01

    The amphibian papilla (AP) is the principal auditory organ of the frog. Anatomical and neurophysiological evidence suggests that this hearing organ utilizes both mechanical and electrical (hair cell-based) frequency tuning mechanisms, yet relatively little is known about the electrophysiology of AP hair cells. Using the whole-cell patch-clamp technique, we have investigated the electrical properties and ionic currents of isolated hair cells along the rostrocaudal axis of the AP. Electrical resonances were observed in the voltage response of hair cells harvested from the rostral and medial, but not caudal, regions of the AP. Two ionic currents, ICa and IK(Ca), were observed in every hair cell; however, their amplitudes varied substantially along the epithelium. Only rostral hair cells exhibited an inactivating potassium current (IA), whereas an inwardly rectifying potassium current (IK1) was identified only in caudal AP hair cells. Electrically tuned hair cells exhibited resonant frequencies from 50 to 375 Hz, which correlated well with hair cell position and the tonotopic organization of the papilla. Variations in the kinetics of the outward current contribute substantially to the determination of resonant frequency. ICa and IK(Ca) amplitudes increased with resonant frequency, reducing the membrane time constant with increasing resonant frequency. We conclude that a tonotopically organized hair cell substrate exists to support electrical tuning in the rostromedial region of the frog amphibian papilla and that the cellular mechanisms for frequency determination are very similar to those reported for another electrically tuned auditory organ, the turtle basilar papilla.

  19. Streptomycin ototoxicity and hair cell regeneration in the adult pigeon utricle

    Science.gov (United States)

    Frank, T. C.; Dye, B. J.; Newlands, S. D.; Dickman, J. D.

    1999-01-01

    OBJECTIVE: The purpose of this study was to develop a technique to investigate the regeneration of utricular hair cells in the adult pigeon (Columba livia) following complete hair cell loss through administration of streptomycin. STUDY DESIGN: Experimental animal study. METHODS: Animals were divided into four groups. Group 1 received 10 to 15 days of systemic streptomycin injections. Animals in Groups 2 and 3 received a single direct placement of a 1-, 2-, 4-, or 8-mg streptomycin dose into the perilymphatic space. Animals in Groups 1 and 2 were analyzed within 1 week from injection to investigate hair cell destruction, whereas Group 3 was investigated at later dates to study hair cell recovery. Group 4 animals received a control injection of saline into the perilymphatic space. Damage and recovery were quantified by counting hair cells in isolated utricles using scanning electron microscopy. RESULTS: Although systemic injections failed to reliably achieve complete utricular hair cell destruction, a single direct placement of a 2-, 4-, or 8-mg streptomycin dose caused complete destruction within the first week. Incomplete hair cell loss was observed with the 1-mg dose. Over the long term, regeneration of the hair cells was seen with the 2-mg dose but not the 8-mg dose. Control injections of saline into the perilymphatic space caused no measurable hair cell loss. CONCLUSIONS: Direct placement of streptomycin into the perilymph is an effective, reliable method for complete destruction of utricular hair cells while preserving the regenerative potential of the neuroepithelium.

  20. Cyclic dermal BMP signalling regulates stem cell activation during hair regeneration.

    Science.gov (United States)

    Plikus, Maksim V; Mayer, Julie Ann; de la Cruz, Damon; Baker, Ruth E; Maini, Philip K; Maxson, Robert; Chuong, Cheng-Ming

    2008-01-17

    In the age of stem cell engineering it is critical to understand how stem cell activity is regulated during regeneration. Hairs are mini-organs that undergo cyclic regeneration throughout adult life, and are an important model for organ regeneration. Hair stem cells located in the follicle bulge are regulated by the surrounding microenvironment, or niche. The activation of such stem cells is cyclic, involving periodic beta-catenin activity. In the adult mouse, regeneration occurs in waves in a follicle population, implying coordination among adjacent follicles and the extrafollicular environment. Here we show that unexpected periodic expression of bone morphogenetic protein 2 (Bmp2) and Bmp4 in the dermis regulates this process. This BMP cycle is out of phase with the WNT/beta-catenin cycle, thus dividing the conventional telogen into new functional phases: one refractory and the other competent for hair regeneration, characterized by high and low BMP signalling, respectively. Overexpression of noggin, a BMP antagonist, in mouse skin resulted in a markedly shortened refractory phase and faster propagation of the regenerative wave. Transplantation of skin from this mutant onto a wild-type host showed that follicles in donor and host can affect their cycling behaviours mutually, with the outcome depending on the equilibrium of BMP activity in the dermis. Administration of BMP4 protein caused the competent region to become refractory. These results show that BMPs may be the long-sought 'chalone' inhibitors of hair growth postulated by classical experiments. Taken together, results presented in this study provide an example of hierarchical regulation of local organ stem cell homeostasis by the inter-organ macroenvironment. The expression of Bmp2 in subcutaneous adipocytes indicates physiological integration between these two thermo-regulatory organs. Our findings have practical importance for studies using mouse skin as a model for carcinogenesis, intra-cutaneous drug

  1. Paraquat initially damages cochlear support cells leading to anoikis-like hair cell death.

    Science.gov (United States)

    Zhang, Jianhui; Sun, Hong; Salvi, Richard; Ding, Dalian

    2018-07-01

    Paraquat (PQ), one of the most widely used herbicides, is extremely dangerous because it generates the highly toxic superoxide radical. When paraquat was applied to cochlear organotypic cultures, it not only damaged the outer hair cells (OHCs) and inner hair cells (IHCs), but also caused dislocation of the hair cell rows. We hypothesized that the dislocation arose from damage to the support cells (SCs) that anchors hair cells within the epithelium. To test this hypothesis, rat postnatal cochlear cultures were treated with PQ. Shortly after PQ treatment, the rows of OHCs separated from one another and migrated radially away from IHCs suggesting loss of cell-cell adhesion that hold the hair cells in proper alignment. Hair cells dislocation was associated with extensive loss of SCs in the organ of Corti, loss of tympanic border cells (TBCs) beneath the basilar membrane, the early appearance of superoxide staining and caspase-8 labeling in SCs below the OHCs and disintegration of E-cadherin and β-catenin in the organ of Corti. Damage to the TBCs and SCs occurred prior to loss of OHC or IHC loss suggesting a form of detachment-induced apoptosis referred to as anoikis. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Criticality in cell differentiation

    Indian Academy of Sciences (India)

    Indrani Bose

    2017-11-09

    Nov 9, 2017 ... Differentiation is mostly based on binary decisions with the progenitor cells ..... accounts for the dominant part of the remaining variation ... significant loss in information. ..... making in vitro: emerging concepts and novel tools.

  3. Defining the cellular environment in the organ of Corti following extensive hair cell loss: a basis for future sensory cell replacement in the Cochlea.

    Directory of Open Access Journals (Sweden)

    Ruth R Taylor

    Full Text Available BACKGROUND: Following the loss of hair cells from the mammalian cochlea, the sensory epithelium repairs to close the lesions but no new hair cells arise and hearing impairment ensues. For any cell replacement strategy to be successful, the cellular environment of the injured tissue has to be able to nurture new hair cells. This study defines characteristics of the auditory sensory epithelium after hair cell loss. METHODOLOGY/PRINCIPAL FINDINGS: Studies were conducted in C57BL/6 and CBA/Ca mice. Treatment with an aminoglycoside-diuretic combination produced loss of all outer hair cells within 48 hours in both strains. The subsequent progressive tissue re-organisation was examined using immunohistochemistry and electron microscopy. There was no evidence of significant de-differentiation of the specialised columnar supporting cells. Kir4.1 was down regulated but KCC4, GLAST, microtubule bundles, connexin expression patterns and pathways of intercellular communication were retained. The columnar supporting cells became covered with non-specialised cells migrating from the outermost region of the organ of Corti. Eventually non-specialised, flat cells replaced the columnar epithelium. Flat epithelium developed in distributed patches interrupting regions of columnar epithelium formed of differentiated supporting cells. Formation of the flat epithelium was initiated within a few weeks post-treatment in C57BL/6 mice but not for several months in CBA/Ca's, suggesting genetic background influences the rate of re-organisation. CONCLUSIONS/SIGNIFICANCE: The lack of dedifferentiation amongst supporting cells and their replacement by cells from the outer side of the organ of Corti are factors that may need to be considered in any attempt to promote endogenous hair cell regeneration. The variability of the cellular environment along an individual cochlea arising from patch-like generation of flat epithelium, and the possible variability between individuals

  4. Feathers and Fins: Non-mammalian models for hair cell regeneration

    OpenAIRE

    Brignull, Heather R.; Raible, David W.; Stone, Jennifer S.

    2009-01-01

    Death of mechanosensory cells in the inner ear results in two profound disabilities: hearing loss and balance disorders. Although mammals lack the capacity to regenerate hair cells, recent studies in mice and other rodents have offered valuable insight into strategies for stimulating hair cell regeneration in mammals. Investigations of model organisms that retain the ability to form new hair cells after embryogenesis, such as fish and chicks, are equally important and have provided clues as t...

  5. Feathers and fins: non-mammalian models for hair cell regeneration.

    Science.gov (United States)

    Brignull, Heather R; Raible, David W; Stone, Jennifer S

    2009-06-24

    Death of mechanosensory cells in the inner ear results in two profound disabilities: hearing loss and balance disorders. Although mammals lack the capacity to regenerate hair cells, recent studies in mice and other rodents have offered valuable insight into strategies for stimulating hair cell regeneration in mammals. Investigations of model organisms that retain the ability to form new hair cells after embryogenesis, such as fish and birds, are equally important and have provided clues as to the cellular and molecular mechanisms that may block hair cell regeneration in mammals. Here, we summarize studies on hair cell regeneration in the chicken and the zebrafish, discuss specific advantages of each model, and propose future directions for the use of non-mammalian models in understanding hair cell regeneration.

  6. Selective Inner Hair Cell Dysfunction in Chinchillas Impairs Hearing-in-Noise in the Absence of Outer Hair Cell Loss.

    Science.gov (United States)

    Lobarinas, Edward; Salvi, Richard; Ding, Dalian

    2016-04-01

    Poorer hearing in the presence of background noise is a significant problem for the hearing impaired. Ototoxic drugs, ageing, and noise exposure can damage the sensory hair cells of the inner ear that are essential for normal hearing sensitivity. The relationship between outer hair cell (OHC) loss and progressively poorer hearing sensitivity in quiet or in competing background noise is supported by a number of human and animal studies. In contrast, the effect of moderate inner hair cell (IHC) loss or dysfunction shows almost no impact on behavioral measures of hearing sensitivity in quiet, when OHCs remain intact, but the relationship between selective IHC loss and hearing in noise remains relatively unknown. Here, a moderately high dose of carboplatin (75 mg/kg) that produced IHC loss in chinchillas ranging from 40 to 80 % had little effect on thresholds in quiet. However, when tested in the presence of competing broadband (BBN) or narrowband noise (NBN), thresholds increased significantly. IHC loss >60 % increased signal-to-noise ratios (SNRs) for tones (500-11,300 Hz) in competing BBN by 5-10 dB and broadened the masking function under NBN. These data suggest that IHC loss or dysfunction may play a significant role in listening in noise independent of OHC integrity and that these deficits may be present even when thresholds in quiet are within normal limits.

  7. Mammalian Cochlear Hair Cell Regeneration and Ribbon Synapse Reformation

    Directory of Open Access Journals (Sweden)

    Xiaoling Lu

    2016-01-01

    Full Text Available Hair cells (HCs are the sensory preceptor cells in the inner ear, which play an important role in hearing and balance. The HCs of organ of Corti are susceptible to noise, ototoxic drugs, and infections, thus resulting in permanent hearing loss. Recent approaches of HCs regeneration provide new directions for finding the treatment of sensor neural deafness. To have normal hearing function, the regenerated HCs must be reinnervated by nerve fibers and reform ribbon synapse with the dendrite of spiral ganglion neuron through nerve regeneration. In this review, we discuss the research progress in HC regeneration, the synaptic plasticity, and the reinnervation of new regenerated HCs in mammalian inner ear.

  8. Sonic hedgehog initiates cochlear hair cell regeneration through downregulation of retinoblastoma protein

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Na [Otology Skull Base Surgery Department, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Department of Otolaryngology and Program in Neuroscience, Harvard Medical School and Eaton Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA 02114 (United States); Chen, Yan [Central Laboratory, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Wang, Zhengmin [Otology Skull Base Surgery Department, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Institute of Biomedical Sciences, Fudan University, Shanghai 200032 (China); Chen, Guoling [Otology Skull Base Surgery Department, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Lin, Qin [Otology Skull Base Surgery Department, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Department of Otolaryngology, First Affiliated Hospital of Fujian Medical University, Otolaryngology Institute of Fujian Province, Fuzhou (China); Chen, Zheng-Yi, E-mail: Zheng-yi_chen@meei.harvard.edu [Department of Otolaryngology and Program in Neuroscience, Harvard Medical School and Eaton Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA 02114 (United States); Li, Huawei, E-mail: hwli@shmu.edu.cn [Otology Skull Base Surgery Department, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Institute of Biomedical Sciences, Fudan University, Shanghai 200032 (China)

    2013-01-11

    Highlights: Black-Right-Pointing-Pointer Shh activation in neonatal cochleae enhances sensory cell proliferation. Black-Right-Pointing-Pointer Proliferating supporting cells can transdifferentiate into hair cells. Black-Right-Pointing-Pointer Shh promotes proliferation by transiently modulating pRb activity. Black-Right-Pointing-Pointer Shh inhibits pRb by inhibiting transcription and increasing phosphorylation of pRb. -- Abstract: Cell cycle re-entry by cochlear supporting cells and/or hair cells is considered one of the best approaches for restoring hearing loss as a result of hair cell damage. To identify mechanisms that can be modulated to initiate cell cycle re-entry and hair cell regeneration, we studied the effect of activating the sonic hedgehog (Shh) pathway. We show that Shh signaling in postnatal rat cochleae damaged by neomycin leads to renewed proliferation of supporting cells and hair cells. Further, proliferating supporting cells are likely to transdifferentiate into hair cells. Shh treatment leads to inhibition of retinoblastoma protein (pRb) by increasing phosphorylated pRb and reducing retinoblastoma gene transcription. This results in upregulation of cyclins B1, D2, and D3, and CDK1. These results suggest that Shh signaling induces cell cycle re-entry in cochlear sensory epithelium and the production of new hair cells, in part by attenuating pRb function. This study provides an additional route to modulate pRb function with important implications in mammalian hair cell regeneration.

  9. Sonic hedgehog initiates cochlear hair cell regeneration through downregulation of retinoblastoma protein

    International Nuclear Information System (INIS)

    Lu, Na; Chen, Yan; Wang, Zhengmin; Chen, Guoling; Lin, Qin; Chen, Zheng-Yi; Li, Huawei

    2013-01-01

    Highlights: ► Shh activation in neonatal cochleae enhances sensory cell proliferation. ► Proliferating supporting cells can transdifferentiate into hair cells. ► Shh promotes proliferation by transiently modulating pRb activity. ► Shh inhibits pRb by inhibiting transcription and increasing phosphorylation of pRb. -- Abstract: Cell cycle re-entry by cochlear supporting cells and/or hair cells is considered one of the best approaches for restoring hearing loss as a result of hair cell damage. To identify mechanisms that can be modulated to initiate cell cycle re-entry and hair cell regeneration, we studied the effect of activating the sonic hedgehog (Shh) pathway. We show that Shh signaling in postnatal rat cochleae damaged by neomycin leads to renewed proliferation of supporting cells and hair cells. Further, proliferating supporting cells are likely to transdifferentiate into hair cells. Shh treatment leads to inhibition of retinoblastoma protein (pRb) by increasing phosphorylated pRb and reducing retinoblastoma gene transcription. This results in upregulation of cyclins B1, D2, and D3, and CDK1. These results suggest that Shh signaling induces cell cycle re-entry in cochlear sensory epithelium and the production of new hair cells, in part by attenuating pRb function. This study provides an additional route to modulate pRb function with important implications in mammalian hair cell regeneration.

  10. Na+ currents in vestibular type I and type II hair cells of the embryo and adult chicken.

    Science.gov (United States)

    Masetto, S; Bosica, M; Correia, M J; Ottersen, O P; Zucca, G; Perin, P; Valli, P

    2003-08-01

    In birds, type I and type II hair cells differentiate before birth. Here we describe that chick hair cells, from the semicircular canals, begin expressing a voltage-dependent Na current (INa) from embryonic day 14 (E14) and continue to express the current up to hatching (E21). During this period, INa was present in most (31/43) type I hair cells irrespective of their position in the crista, in most type II hair cells located far from the planum semilunatum (48/63), but only occasionally in type II hair cells close to the planum semilunatum (2/35). INa activated close to -60 mV, showed fast time- and voltage-dependent activation and inactivation, and was completely, and reversibly, blocked by submicromolar concentrations of tetrodotoxin (Kd = 17 nM). One peculiar property of INa concerns its steady-state inactivation, which is complete at -60 mV (half-inactivating voltage = -96 mV). INa was found in type I and type II hair cells from the adult chicken as well, where it had similar, although possibly not identical, properties and regional distribution. Current-clamp experiments showed that INa could contribute to the voltage response provided that the cell membrane was depolarized from holding potentials more negative than -80 mV. When recruited, INa produced a significant acceleration of the cell membrane depolarization, which occasionally elicited a large rapid depolarization followed by a rapid repolarization (action-potential-like response). Possible physiological roles for INa in the embryo and adult chicken are discussed.

  11. Valproic acid induces hair regeneration in murine model and activates alkaline phosphatase activity in human dermal papilla cells.

    Directory of Open Access Journals (Sweden)

    Soung-Hoon Lee

    Full Text Available Alopecia is the common hair loss problem that can affect many people. However, current therapies for treatment of alopecia are limited by low efficacy and potentially undesirable side effects. We have identified a new function for valproic acid (VPA, a GSK3β inhibitor that activates the Wnt/β-catenin pathway, to promote hair re-growth in vitro and in vivo.Topical application of VPA to male C3H mice critically stimulated hair re-growth and induced terminally differentiated epidermal markers such as filaggrin and loricrin, and the dermal papilla marker alkaline phosphatase (ALP. VPA induced ALP in human dermal papilla cells by up-regulating the Wnt/β-catenin pathway, whereas minoxidil (MNX, a drug commonly used to treat alopecia, did not significantly affect the Wnt/β-catenin pathway. VPA analogs and other GSK3β inhibitors that activate the Wnt/β-catenin pathway such as 4-phenyl butyric acid, LiCl, and BeCl(2 also exhibited hair growth-promoting activities in vivo. Importantly, VPA, but not MNX, successfully stimulate hair growth in the wounds of C3H mice.Our findings indicate that small molecules that activate the Wnt/β-catenin pathway, such as VPA, can potentially be developed as drugs to stimulate hair re-growth.

  12. Hair follicle defects and squamous cell carcinoma formation in Smad4 conditional knockout mouse skin.

    Science.gov (United States)

    Qiao, W; Li, A G; Owens, P; Xu, X; Wang, X-J; Deng, C-X

    2006-01-12

    Smad4 is the common mediator for TGFbeta signals, which play important functions in many biological processes. To study the role of Smad4 in skin development and epidermal tumorigenesis, we disrupted this gene in skin using the Cre-loxP approach. We showed that absence of Smad4 blocked hair follicle differentiation and cycling, leading to a progressive hair loss of mutant (MT) mice. MT hair follicles exhibited diminished expression of Lef1, and increased proliferative cells in the outer root sheath. Additionally, the skin of MT mice exhibited increased proliferation of basal keratinocytes and epidermal hyperplasia. Furthermore, we provide evidence that the absence of Smad4 resulted in a block of both TGFbeta and bone morphogenetic protein (BMP) signaling pathways, including p21, a well-known cyclin-dependent kinase inhibitor. Consequently, all MT mice developed spontaneous malignant skin tumors from 3 months to 13 months of age. The majority of tumors are malignant squamous cell carcinomas. A most notable finding is that tumorigenesis is accompanied by inactivation of phosphatase and tensin homolog deleted on chromosome 10 (Pten), activation of AKT, fast proliferation and nuclear accumulation of cyclin D1. These observations revealed the essential functions of Smad4-mediated signals in repressing skin tumor formation through the TGFbeta/BMP pathway, which interacts with the Pten signaling pathway.

  13. Constitutive transgene expression of Stem Cell Antigen-1 in the hair follicle alters the sensitivity to tumor formation and progression

    Directory of Open Access Journals (Sweden)

    Rikke Christensen

    2017-08-01

    Full Text Available The cell surface protein Stem Cell Antigen-1 (Sca-1 marks stem or progenitor cells in several murine tissues and is normally upregulated during cancer development. Although the specific function of Sca-1 remains unknown, Sca-1 seems to play a role in proliferation, differentiation and cell migration in a number of tissues. In the skin epithelium, Sca-1 is highly expressed in the interfollicular epidermis but is absent in most compartments of the hair follicle; however, the function of Sca-1 in the skin has not been investigated. To explore the role of Sca-1 in normal and malignant skin development we generated transgenic mice that express Sca-1 in the hair follicle stem cells that are normally Sca-1 negative. Development of hair follicles and interfollicular epidermis appeared normal in Sca-1 mutant mice; however, follicular induction of Sca-1 expression in bulge region and isthmus stem cells reduced the overall yield of papillomas in a chemical carcinogenesis protocol. Despite that fewer papillomas developed in transgenic mice a higher proportion of the papillomas underwent malignant conversion. These findings suggest that overexpression of Sca-1 in the hair follicle stem cells contributes at different stages of tumour development. In early stages, overexpression of Sca-1 decreases tumour formation while at later stages overexpression of Sca-1 seems to drive tumours towards malignant progression.

  14. REGULATED VESICULAR TRAFFICKING OF SPECIFIC PCDH15 AND VLGR1 VARIANTS IN AUDITORY HAIR CELLS

    Science.gov (United States)

    Zallocchi, Marisa; Delimont, Duane; Meehan, Daniel T.; Cosgrove, Dominic

    2012-01-01

    Usher syndrome is a genetically heterogeneous disorder characterized by hearing and balance dysfunction and progressive retinitis pigmentosa. Mouse models carrying mutations for the nine Usher-associated genes have splayed stereocilia and some show delayed maturation of ribbon synapses suggesting these proteins may play different roles in terminal differentiation of auditory hair cells. The presence of the Usher proteins at the basal and apical aspects of the neurosensory epithelia suggests the existence of regulated trafficking through specific transport proteins and routes. Immature mouse cochleae and UB/OC-1 cells were used in this work to address whether specific variants of PCDH15 and VLGR1 are being selectively transported to opposite poles of the hair cells. Confocal co-localization studies between apical and basal vesicular markers and the different PCDH15 and VLGR1 variants along with sucrose density gradients and the use of vesicle trafficking inhibitors show the existence of Usher protein complexes in at least two vesicular sub-pools. The apically trafficked pool co-localized with the early endosomal vesicle marker, rab5, while the basally trafficked pool associates with membrane microdomains and SNAP25. Moreover, co-immunoprecipitation experiments between SNAP25 and VLGR1 show a physical interaction of these two proteins in organ of Corti and brain. Collectively, these findings establish the existence of a differential vesicular trafficking mechanism for specific Usher protein variants in mouse cochlear hair cells, with the apical variants playing a potential role in endosomal recycling and stereocilia development/maintenance and the basolateral variants involved in vesicle docking and/or fusion through SNAP25-mediated interactions. PMID:23035094

  15. A simple method for purification of vestibular hair cells and non-sensory cells, and application for proteomic analysis.

    Science.gov (United States)

    Herget, Meike; Scheibinger, Mirko; Guo, Zhaohua; Jan, Taha A; Adams, Christopher M; Cheng, Alan G; Heller, Stefan

    2013-01-01

    Mechanosensitive hair cells and supporting cells comprise the sensory epithelia of the inner ear. The paucity of both cell types has hampered molecular and cell biological studies, which often require large quantities of purified cells. Here, we report a strategy allowing the enrichment of relatively pure populations of vestibular hair cells and non-sensory cells including supporting cells. We utilized specific uptake of fluorescent styryl dyes for labeling of hair cells. Enzymatic isolation and flow cytometry was used to generate pure populations of sensory hair cells and non-sensory cells. We applied mass spectrometry to perform a qualitative high-resolution analysis of the proteomic makeup of both the hair cell and non-sensory cell populations. Our conservative analysis identified more than 600 proteins with a false discovery rate of Analysis of proteins exclusively detected in either population revealed 64 proteins that were specific to hair cells and 103 proteins that were only detectable in non-sensory cells. Statistical analyses extended these groups by 53 proteins that are strongly upregulated in hair cells versus non-sensory cells and vice versa by 68 proteins. Our results demonstrate that enzymatic dissociation of styryl dye-labeled sensory hair cells and non-sensory cells is a valid method to generate pure enough cell populations for flow cytometry and subsequent molecular analyses.

  16. Genetically induced cell death in bulge stem cells reveals their redundancy for hair and epidermal regeneration.

    Science.gov (United States)

    Driskell, Iwona; Oeztuerk-Winder, Feride; Humphreys, Peter; Frye, Michaela

    2015-03-01

    Adult mammalian epidermis contains multiple stem cell populations in which quiescent and more proliferative stem and progenitor populations coexist. However, the precise interrelation of these populations in homeostasis remains unclear. Here, we blocked the contribution of quiescent keratin 19 (K19)-expressing bulge stem cells to hair follicle formation through genetic ablation of the essential histone methyltransferase Setd8 that is required for the maintenance of adult skin. Deletion of Setd8 eliminated the contribution of bulge cells to hair follicle regeneration through inhibition of cell division and induction of cell death, but the growth and morphology of hair follicles were unaffected. Furthermore, ablation of Setd8 in the hair follicle bulge blocked the contribution of K19-postive stem cells to wounded epidermis, but the wound healing process was unaltered. Our data indicate that quiescent bulge stem cells are dispensable for hair follicle regeneration and epidermal injury in the short term and support the hypothesis that quiescent and cycling stem cell populations are equipotent. © 2014 AlphaMed Press.

  17. Drive mechanisms to the inner and outer hair cell stereocilia

    Science.gov (United States)

    Maftoon, Nima; Motallebzadeh, Hamid; Guinan, John J.; Puria, Sunil

    2018-05-01

    It has been long believed that inner hair cell (IHC) stimulation can be gleaned from the classic ter-Kuile shear motion between the reticular lamina (RL) and tectorial membrane (TM). The present study explores this and other IHC stimulation mechanisms using a finite-element-model representation of an organ of Corti (OoC) cross section with fluid-structure interaction. A 3-D model of a cross section of the OoC including soft tissue and the fluid in the sub-tectorial space, tunnel of Corti and above the TM was formulated based on anatomical measurements from the gerbil apical turn. The outer hair cells (OHCs), Deiter's cells and their phalangeal processes are represented as Y-shaped building-block elements. Each of the IHC and OHC bundles is represented by a single sterocilium. Linearized Navier-Stokes equations coupled with linear-elastic equations discretized with tetrahedral elements are solved in the frequency domain. We evaluated the dynamic changes in the OoC motion including sub-tectorial gap dimensions for 0.1 to 10 kHz input frequencies. Calculations show the classic ter-Kuile motion but more importantly they show that the gap-height changes which produce oscillatory radial flow in the subtectorial space. Phase changes in the stereocilia across OHC rows and the IHC are also observed.

  18. Characterization of Rat Hair Follicle Stem Cells Selected by Vario Magnetic Activated Cell Sorting System

    International Nuclear Information System (INIS)

    Huang, Enyi; Lian, Xiaohua; Chen, Wei; Yang, Tian; Yang, Li

    2009-01-01

    Hair follicle stem cells (HfSCs) play crucial roles in hair follicle morphogenesis and hair cycling. These stem cells are self-renewable and have the multi-lineage potential to generate epidermis, sebaceous glands, and hair follicle. The separation and identification of hair follicle stem cells are important for further research in stem cell biology. In this study, we report on the successful enrichment of rat hair follicle stem cells through vario magnetic activated cell sorting (Vario MACS) and the biological characteristics of the stem cells. We chose the HfSCs positive surface markers CD34, α6-integrin and the negative marker CD71 to design four isolation strategies: positive selection with single marker of CD34, positive selection with single marker of α6-integrin, CD71 depletion followed by CD34 positive selection, and CD71 depletion followed by α6-integrin positive selection. The results of flow cytometry analysis showed that all four strategies had ideal effects. Specifically, we conducted a series of researches on HfSCs characterized by their high level of CD34, termed CD34 bri cells, and low to undetectable expression of CD34, termed CD34 dim cells. CD34 bri cells had greater proliferative potential and higher colony-forming ability than CD34 dim cells. Furthermore, CD34 bri cells had some typical characteristics as progenitor cells, such as large nucleus, obvious nucleolus, large nuclear:cytoplasmic ratio and few cytoplasmic organelles. Our findings clearly demonstrated that HfSCs with high purity and viability could be successfully enriched with Vario MACS

  19. Regional analysis of whole cell currents from hair cells of the turtle posterior crista.

    Science.gov (United States)

    Brichta, Alan M; Aubert, Anne; Eatock, Ruth Anne; Goldberg, Jay M

    2002-12-01

    The turtle posterior crista is made up of two hemicristae, each consisting of a central zone containing type I and type II hair cells and a surrounding peripheral zone containing only type II hair cells and extending from the planum semilunatum to the nonsensory torus. Afferents from various regions of a hemicrista differ in their discharge properties. To see if afferent diversity is related to the basolateral currents of the hair cells innervated, we selectively harvested type I and II hair cells from the central zone and type II hair cells from two parts of the peripheral zone, one near the planum and the other near the torus. Voltage-dependent currents were studied with the whole cell, ruptured-patch method and characterized in voltage-clamp mode. We found regional differences in both outwardly and inwardly rectifying voltage-sensitive currents. As in birds and mammals, type I hair cells have a distinctive outwardly rectifying current (I(K,L)), which begins activating at more hyperpolarized voltages than do the outward currents of type II hair cells. Activation of I(K,L) is slow and sigmoidal. Maximal outward conductances are large. Outward currents in type II cells vary in their activation kinetics. Cells with fast kinetics are associated with small conductances and with partial inactivation during 200-ms depolarizing voltage steps. Almost all type II cells in the peripheral zone and many in the central zone have fast kinetics. Some type II cells in the central zone have large outward currents with slow kinetics and little inactivation. Although these currents resemble I(K,L), they can be distinguished from the latter both electrophysiologically and pharmacologically. There are two varieties of inwardly rectifying currents in type II hair cells: activation of I(K1) is rapid and monoexponential, whereas that of I(h) is slow and sigmoidal. Many type II cells either have both inward currents or only have I(K1); very few cells only have I(h). Inward currents are

  20. Regulatory T Cells in Skin Facilitate Epithelial Stem Cell Differentiation.

    Science.gov (United States)

    Ali, Niwa; Zirak, Bahar; Rodriguez, Robert Sanchez; Pauli, Mariela L; Truong, Hong-An; Lai, Kevin; Ahn, Richard; Corbin, Kaitlin; Lowe, Margaret M; Scharschmidt, Tiffany C; Taravati, Keyon; Tan, Madeleine R; Ricardo-Gonzalez, Roberto R; Nosbaum, Audrey; Bertolini, Marta; Liao, Wilson; Nestle, Frank O; Paus, Ralf; Cotsarelis, George; Abbas, Abul K; Rosenblum, Michael D

    2017-06-01

    The maintenance of tissue homeostasis is critically dependent on the function of tissue-resident immune cells and the differentiation capacity of tissue-resident stem cells (SCs). How immune cells influence the function of SCs is largely unknown. Regulatory T cells (Tregs) in skin preferentially localize to hair follicles (HFs), which house a major subset of skin SCs (HFSCs). Here, we mechanistically dissect the role of Tregs in HF and HFSC biology. Lineage-specific cell depletion revealed that Tregs promote HF regeneration by augmenting HFSC proliferation and differentiation. Transcriptional and phenotypic profiling of T regs and HFSCs revealed that skin-resident Tregs preferentially express high levels of the Notch ligand family member, Jagged 1 (Jag1). Expression of Jag1 on Tregs facilitated HFSC function and efficient HF regeneration. Taken together, our work demonstrates that Tregs in skin play a major role in HF biology by promoting the function of HFSCs. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Effect of JNK inhibitor SP600125 on hair cell regeneration in zebrafish (Danio rerio) larvae

    Science.gov (United States)

    Sun, Shaoyang; Wang, Xu; Li, Wenyan; Li, Huawei

    2016-01-01

    The c-Jun amino-terminal kinase (JNK) proteins are a subgroup of the mitogen-activated protein kinase family. They play a complex role in cell proliferation, survival, and apoptosis. Here, we report a novel role of JNK signalling in hair cell regeneration. We eliminated hair cells of 5-day post-fertilization zebrafish larvae using neomycin followed by JNK inhibition with SP600125. JNK inhibition strongly decreased the number of regenerated hair cells in response to neomycin damage. These changes were associated with reduced proliferation. JNK inhibition also increased cleaved caspase-3 activity and induced apoptosis in regenerating neuromasts. Finally, JNK inhibition with SP600125 decreased the expression of genes related to Wnt. Over-activation of the Wnt signalling pathway partly rescued the hair cell regeneration defects induced by JNK inhibition. Together, our findings provide novel insights into the function of JNK and show that JNK inhibition blocks hair cell regeneration by controlling the Wnt signalling pathway. PMID:27438150

  2. Position-dependent patterning of spontaneous action potentials in immature cochlear inner hair cells

    Science.gov (United States)

    Johnson, Stuart L.; Eckrich, Tobias; Kuhn, Stephanie; Zampini, Valeria; Franz, Christoph; Ranatunga, Kishani M.; Roberts, Terri P.; Masetto, Sergio; Knipper, Marlies; Kros, Corné J.; Marcotti, Walter

    2011-01-01

    Spontaneous action potential activity is crucial for mammalian sensory system development. In the auditory system, patterned firing activity has been observed in immature spiral ganglion cells and brain-stem neurons and is likely to depend on cochlear inner hair cell (IHC) action potentials. It remains uncertain whether spiking activity is intrinsic to developing IHCs and whether it shows patterning. We found that action potentials are intrinsically generated by immature IHCs of altricial rodents and that apical IHCs exhibit bursting activity as opposed to more sustained firing in basal cells. We show that the efferent neurotransmitter ACh, by fine-tuning the IHC’s resting membrane potential (Vm), is crucial for the bursting pattern in apical cells. Endogenous extracellular ATP also contributes to the Vm of apical and basal IHCs by activating SK2 channels. We hypothesize that the difference in firing pattern along the cochlea instructs the tonotopic differentiation of IHCs and auditory pathway. PMID:21572434

  3. Sonic Hedgehog Initiates Cochlear Hair Cell Regeneration through Downregulation of Retinoblastoma Protein

    Science.gov (United States)

    Lu, Na; Chen, Yan; Wang, Zhengmin; Chen, Guoling; Lin, Qin; Chen, Zheng-Yi; Li, Huawei

    2013-01-01

    Cell cycle re-entry by cochlear supporting cells and/or hair cells is considered one of the best approaches for restoring hearing loss as a result of hair cell damage. To identify mechanisms that can be modulated to initiate cell cycle re-entry and hair cell regeneration, we studied the effect of activating the sonic hedgehog (Shh) pathway. We show that Shh signaling in postnatal rat cochleae damaged by neomycin leads to renewed proliferation of supporting cells and hair cells. Further, proliferating supporting cells are likely to transdifferentiate into hair cells. Shh treatment leads to inhibition of retinoblastoma protein (pRb) by increasing phosphorylated pRb and reducing retinoblastoma gene transcription. This results in upregulation of cyclins B1, D2, and D3, and CDK1. These results suggest that Shh signaling induces cell cycle re-entry in cochlear sensory epithelium and the production of new hair cells, in part by attenuating pRb function. This study provides an additional route to modulate pRb function with important implications in mammalian hair cell regeneration. PMID:23211596

  4. Natural bizbenzoquinoline derivatives protect zebrafish lateral line sensory hair cells from aminoglycoside toxicity

    Directory of Open Access Journals (Sweden)

    Matthew eKruger

    2016-03-01

    Full Text Available Moderate to severe hearing loss affects 360 million people worldwide and most often results from damage to sensory hair cells. Hair cell damage can result from aging, genetic mutations, excess noise exposure, and certain medications including aminoglycoside antibiotics. Aminoglycosides are effective at treating infections associated with cystic fibrosis and other life-threatening conditions such as sepsis, but cause hearing loss in 20-30% of patients. It is therefore imperative to develop new therapies to combat hearing loss and allow safe use of these potent antibiotics. We approach this drug discovery question using the larval zebrafish lateral line because zebrafish hair cells are structurally and functionally similar to mammalian inner ear hair cells and respond similarly to toxins. We screened a library of 502 natural compounds in order to identify novel hair cell protectants. Our screen identified four bisbenzylisoquinoline derivatives: berbamine, E6 berbamine, hernandezine, and isotetrandrine, each of which robustly protected hair cells from aminoglycoside-induced damage. Using fluorescence microscopy and electrophysiology, we demonstrated that the natural compounds confer protection by reducing antibiotic uptake into hair cells and showed that hair cells remain functional during and after incubation in E6 berbamine. We also determined that these natural compounds do not reduce antibiotic efficacy. Together, these natural compounds represent a novel source of possible otoprotective drugs that may offer therapeutic options for patients receiving aminoglycoside treatment.

  5. Pairwise coupling of hair cell transducer channels links auditory sensitivity and dynamic range

    NARCIS (Netherlands)

    van Netten, Sietse M.; Meulenberg, Cecil J. W.; Lennan, George W. T.; Kros, Corne J.

    Hair cells in the inner ear provide the basis for the exquisite hearing capabilities of mammals. These cells transduce sound-induced displacements of their mechanosensitive hair bundle into electrical currents within a fraction of a millisecond and with nanometer fidelity. Excitatory displacements

  6. Biotechnology in the Treatment of Sensorineural Hearing Loss: Foundations and Future of Hair Cell Regeneration

    Science.gov (United States)

    Parker, Mark A.

    2011-01-01

    Purpose: To provide an overview of the methodologies involved in the field of hair cell regeneration. First, the author provides a tutorial on the biotechnological foundations of this field to assist the reader in the comprehension and interpretation of the research involved in hair cell regeneration. Next, the author presents a review of stem…

  7. Discussion: Changes in Vocal Production and Auditory Perception after Hair Cell Regeneration.

    Science.gov (United States)

    Ryals, Brenda M.; Dooling, Robert J.

    2000-01-01

    A bird study found that with sufficient time and training after hair cell and hearing loss and hair cell regeneration, the mature avian auditory system can accommodate input from a newly regenerated periphery sufficiently to allow for recognition of previously familiar vocalizations and the learning of new complex acoustic classifications.…

  8. Membrane properties of chick semicircular canal hair cells in situ during embryonic development.

    Science.gov (United States)

    Masetto, S; Perin, P; Malusà, A; Zucca, G; Valli, P

    2000-05-01

    The electrophysiological properties of developing vestibular hair cells have been investigated in a chick crista slice preparation, from embryonic day 10 (E10) to E21 (when hatching would occur). Patch-clamp whole-cell experiments showed that different types of ion channels are sequentially expressed during development. An inward Ca(2+) current and a slow outward rectifying K(+) current (I(K(V))) are acquired first, at or before E10, followed by a rapid transient K(+) current (I(K(A))) at E12, and by a small Ca-dependent K(+) current (I(KCa)) at E14. Hair cell maturation then proceeds with the expression of hyperpolarization-activated currents: a slow I(h) appears first, around E16, followed by the fast inward rectifier I(K1) around E19. From the time of its first appearance, I(K(A)) is preferentially expressed in peripheral (zone 1) hair cells, whereas inward rectifying currents are preferentially expressed in intermediate (zone 2) and central (zone 3) hair cells. Each conductance conferred distinctive properties on hair cell voltage response. Starting from E15, some hair cells, preferentially located at the intermediate region, showed the amphora shape typical of type I hair cells. From E17 (a time when the afferent calyx is completed) these cells expressed I(K, L), the signature current of mature type I hair cells. Close to hatching, hair cell complements and regional organization of ion currents appeared similar to those reported for the mature avian crista. By the progressive acquisition of different types of inward and outward rectifying currents, hair cell repolarization after both positive- and negative-current injections is greatly strengthened and speeded up.

  9. Spontaneous hair cell regeneration in the mouse utricle following gentamicin ototoxicity.

    Science.gov (United States)

    Kawamoto, Kohei; Izumikawa, Masahiko; Beyer, Lisa A; Atkin, Graham M; Raphael, Yehoash

    2009-01-01

    Whereas most epithelial tissues turn-over and regenerate after a traumatic lesion, this restorative ability is diminished in the sensory epithelia of the inner ear; it is absent in the cochlea and exists only in a limited capacity in the vestibular epithelium. The extent of regeneration in vestibular hair cells has been characterized for several mammalian species including guinea pig, rat, and chinchilla, but not yet in mouse. As the fundamental model species for investigating hereditary disease, the mouse can be studied using a wide variety of genetic and molecular tools. To design a mouse model for vestibular hair cell regeneration research, an aminoglycoside-induced method of complete hair cell elimination was developed in our lab and applied to the murine utricle. Loss of utricular hair cells was observed using scanning electron microscopy, and corroborated by a loss of fluorescent signal in utricles from transgenic mice with GFP-positive hair cells. Regenerative capability was characterized at several time points up to six months following insult. Using scanning electron microscopy, we observed that as early as two weeks after insult, a few immature hair cells, demonstrating the characteristic immature morphology indicative of regeneration, could be seen in the utricle. As time progressed, larger numbers of immature hair cells could be seen along with some mature cells resembling surface morphology of type II hair cells. By six months post-lesion, numerous regenerated hair cells were present in the utricle, however, neither their number nor their appearance was normal. A BrdU assay suggested that at least some of the regeneration of mouse vestibular hair cells involved mitosis. Our results demonstrate that the vestibular sensory epithelium in mice can spontaneously regenerate, elucidate the time course of this process, and identify involvement of mitosis in some cases. These data establish a road map of the murine vestibular regenerative process, which can be

  10. Osteoblastic cells: differentiation and trans-differentiation

    DEFF Research Database (Denmark)

    Kassem, Moustapha; Abdallah, Basem; Saeed, Hamid

    2008-01-01

    The osteoblast is the bone forming cell and is derived from mesenchymal stem cells (MSC) present among the bone marrow stroma. MSC are capable of multi-lineage differentiation into mesoderm-type cells such as osteoblasts and adipocytes. Understanding the mechanisms underlying osteoblast different...

  11. Stem Cell-Associated Marker Expression in Canine Hair Follicles.

    Science.gov (United States)

    Gerhards, Nora M; Sayar, Beyza S; Origgi, Francesco C; Galichet, Arnaud; Müller, Eliane J; Welle, Monika M; Wiener, Dominique J

    2016-03-01

    Functional hair follicle (HF) stem cells (SCs) are crucial to maintain the constant recurring growth of hair. In mice and humans, SC subpopulations with different biomarker expression profiles have been identified in discrete anatomic compartments of the HF. The rare studies investigating canine HF SCs have shown similarities in biomarker expression profiles to that of mouse and human SCs. The aim of our study was to broaden the current repertoire of SC-associated markers and their expression patterns in the dog. We combined analyses on the expression levels of CD34, K15, Sox9, CD200, Nestin, LGR5 and LGR6 in canine skin using RT-qPCR, the corresponding proteins in dog skin lysates, and their expression patterns in canine HFs using immunohistochemistry. Using validated antibodies, we were able to define the location of CD34, Sox9, Keratin15, LGR5 and Nestin in canine HFs and confirm that all tested biomarkers are expressed in canine skin. Our results show similarities between the expression profile of canine, human and mouse HF SC markers. This repertoire of biomarkers will allow us to conduct functional studies and investigate alterations in the canine SC compartment of different diseases, like alopecia or skin cancer with the possibility to extend relevant findings to human patients. © 2016 The Histochemical Society.

  12. 2,3-Dihydroxybenzoic acid attenuates kanamycin-induced volume reduction in mouse utricular type I hair cells

    DEFF Research Database (Denmark)

    Severinsen, Stig Åvall; Kirkegaard, Mette; Nyengaard, Jens Randel

    2006-01-01

    injection. Total volume of the utricle, as well as total number of hair and supporting cells, were estimated on light microscopic sections. Total volume and mean volume of hair cell types I and II and supporting cells were estimated on digital transmission electron micrographs. Total volume of the utricular...... macula, hair cell type I and supporting cells decreased significantly in animals injected with kanamycin but not in animals co-treated with DHB. Hair and supporting cell numbers remained unchanged in all three groups. In conclusion, the kanamycin-induced volume reduction of type I hair cells...

  13.  Hair follicle as a novel source of stem cells

    Directory of Open Access Journals (Sweden)

    Romana Joachimiak

    2012-04-01

    Full Text Available  Tissue engineering as a rapidly developing branch of science offers hope for the use of its products in medical practice. Among the components of tissue substitutes are different types of cells, especially stem cells. A promising source of adult stem cells is hair follicles. Development of follicles in the skin takes place even during fetal life. They arise due to the impact of epidermal and mesenchymal cells. The next steps in the formation of hair follicles are under the control of many factors. Hair follicles are the niche of various stem cell populations and are a major source of cells responsible for regeneration of the hair, sebaceous glands and epidermis. The term „hair follicle stem cells” is most often used in relation to the epithelial cell population. Hair follicle stem cell studies are complicated by the fact that these stem cells divide relatively rarely.The aim of this study is to present the characteristics of cells isolated from the hair follicle in the light of recent research.

  14. The delayed rectifier, IKI, is the major conductance in type I vestibular hair cells across vestibular end organs

    Science.gov (United States)

    Ricci, A. J.; Rennie, K. J.; Correia, M. J.

    1996-01-01

    Hair cells were dissociated from the semicircular canal, utricle, lagena and saccule of white king pigeons. Type I hair cells were identified morphologically based on the ratios of neck width to cuticular plate width (NPR rectifier characterized previously in semicircular canal hair cells as IKI.

  15. Distinct roles of Eps8 in the maturation of cochlear and vestibular hair cells.

    Science.gov (United States)

    Tavazzani, Elisa; Spaiardi, Paolo; Zampini, Valeria; Contini, Donatella; Manca, Marco; Russo, Giancarlo; Prigioni, Ivo; Marcotti, Walter; Masetto, Sergio

    2016-07-22

    Several genetic mutations affecting the development and function of mammalian hair cells have been shown to cause deafness but not vestibular defects, most likely because vestibular deficits are sometimes centrally compensated. The study of hair cell physiology is thus a powerful direct approach to ascertain the functional status of the vestibular end organs. Deletion of Epidermal growth factor receptor pathway substrate 8 (Eps8), a gene involved in actin remodeling, has been shown to cause deafness in mice. While both inner and outer hair cells from Eps8 knockout (KO) mice showed abnormally short stereocilia, inner hair cells (IHCs) also failed to acquire mature-type ion channels. Despite the fact that Eps8 is also expressed in vestibular hair cells, Eps8 KO mice show no vestibular deficits. In the present study we have investigated the properties of vestibular Type I and Type II hair cells in Eps8-KO mice and compared them to those of cochlear IHCs. In the absence of Eps8, vestibular hair cells show normally long kinocilia, significantly shorter stereocilia and a normal pattern of basolateral voltage-dependent ion channels. We have also found that while vestibular hair cells from Eps8 KO mice show normal voltage responses to injected sinusoidal currents, which were used to mimic the mechanoelectrical transducer current, IHCs lose their ability to synchronize their responses to the stimulus. We conclude that the absence of Eps8 produces a weaker phenotype in vestibular hair cells compared to cochlear IHCs, since it affects the hair bundle morphology but not the basolateral membrane currents. This difference is likely to explain the absence of obvious vestibular dysfunction in Eps8 KO mice. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  16. Daunomycin accumulation and induction of programmed cell death in rat hair follicles

    DEFF Research Database (Denmark)

    Shin, Masashi; Larsson, Lars-Inge; Hougaard, David M.

    2009-01-01

    The anthracycline antibiotic daunomycin (DM) is useful for the treatment of leukemia but has side-effects such as alopecia. Using immunocytochemistry, we show that, after a single i.v. injection, DM accumulates in the nuclei of matrix cells and in the outer root sheath of hair follicles. DM......-positive matrix cells are detectable up to 48 h after injection and exhibit a characteristic granular morphology, which is not observed in saline-injected controls. TUNEL-staining has revealed that DM injection induces programmed cell death (PCD) in rat hair follicles. Cells undergoing PCD are detectable as late...... (PCD type 2). Interestingly, little, if any, DM accumulation or apoptosis has been detected in the dermal hair papillae. This may have a bearing on potential regeneration of the hair follicles. Thus, DM accumulates in a characteristic pattern in hair follicles. This accumulation is associated...

  17. The nude mutant gene Foxn1 is a HOXC13 regulatory target during hair follicle and nail differentiation.

    Science.gov (United States)

    Potter, Christopher S; Pruett, Nathanael D; Kern, Michael J; Baybo, Mary Ann; Godwin, Alan R; Potter, Kathleen A; Peterson, Ron L; Sundberg, John P; Awgulewitsch, Alexander

    2011-04-01

    Among the Hox genes, homeobox C13 (Hoxc13) has been shown to be essential for proper hair shaft differentiation, as Hoxc13 gene-targeted (Hoxc13(tm1Mrc)) mice completely lack external hair. Because of the remarkable overt phenotypic parallels to the Foxn1(nu) (nude) mutant mice, we sought to determine whether Hoxc13 and forkhead box N1 (Foxn1) might act in a common pathway of hair follicle (HF) differentiation. We show that the alopecia exhibited by both the Hoxc13(tm1Mrc) and Foxn1(nu) mice is because of strikingly similar defects in hair shaft differentiation and that both mutants suffer from a severe nail dystrophy. These phenotypic similarities are consistent with the extensive overlap between Hoxc13 and Foxn1 expression patterns in the HF and the nail matrix. Furthermore, DNA microarray analysis of skin from Hoxc13(tm1Mrc) mice identified Foxn1 as significantly downregulated along with numerous hair keratin genes. This Foxn1 downregulation apparently reflects the loss of direct transcriptional control by HOXC13 as indicated by our results obtained through co-transfection and chromatin immunoprecipitation (ChIP) assays. As presented in the discussion, these data support a regulatory model of keratinocyte differentiation in which HOXC13-dependent activation of Foxn1 is part of a regulatory cascade controlling the expression of terminal differentiation markers.

  18. Hair casts

    OpenAIRE

    Sweta S Parmar; Kirti S Parmar; Bela J Shah

    2014-01-01

    Hair casts or pseudonits are circumferential concretions, which cover the hair shaft in such a way that, it could be easily removed. They are thin, cylindrical, and elongated in length. We present an unusual case of an 8-year-old girl presenting with hair casts. Occurrence of these is unusual, and they may have varied associations. This patient was suffering from developmental delay. It is commonly misdiagnosed as and very important to differentiate from pediculosis capitis.

  19. The acquisition of mechano-electrical transducer current adaptation in auditory hair cells requires myosin VI

    NARCIS (Netherlands)

    Marcotti, Walter; Corns, Laura F.; Goodyear, Richard J.; Rzadzinska, Agnieszka K.; Avraham, Karen B.; Steel, Karen P.; Richardson, Guy P.; Kros, Corne J.

    2016-01-01

    The transduction of sound into electrical signals occurs at the hair bundles atop sensory hair cells in the cochlea, by means of mechanosensitive ion channels, the mechano-electrical transducer (MET) channels. The MET currents decline during steady stimuli; this is termed adaptation and ensures they

  20. Gene expression underlying enhanced, steroid-dependent auditory sensitivity of hair cell epithelium in a vocal fish.

    Science.gov (United States)

    Fergus, Daniel J; Feng, Ni Y; Bass, Andrew H

    2015-10-14

    Successful animal communication depends on a receiver's ability to detect a sender's signal. Exemplars of adaptive sender-receiver coupling include acoustic communication, often important in the context of seasonal reproduction. During the reproductive summer season, both male and female midshipman fish (Porichthys notatus) exhibit similar increases in the steroid-dependent frequency sensitivity of the saccule, the main auditory division of the inner ear. This form of auditory plasticity enhances detection of the higher frequency components of the multi-harmonic, long-duration advertisement calls produced repetitively by males during summer nights of peak vocal and spawning activity. The molecular basis of this seasonal auditory plasticity has not been fully resolved. Here, we utilize an unbiased transcriptomic RNA sequencing approach to identify differentially expressed transcripts within the saccule's hair cell epithelium of reproductive summer and non-reproductive winter fish. We assembled 74,027 unique transcripts from our saccular epithelial sequence reads. Of these, 6.4 % and 3.0 % were upregulated in the reproductive and non-reproductive saccular epithelium, respectively. Gene ontology (GO) term enrichment analyses of the differentially expressed transcripts showed that the reproductive saccular epithelium was transcriptionally, translationally, and metabolically more active than the non-reproductive epithelium. Furthermore, the expression of a specific suite of candidate genes, including ion channels and components of steroid-signaling pathways, was upregulated in the reproductive compared to the non-reproductive saccular epithelium. We found reported auditory functions for 14 candidate genes upregulated in the reproductive midshipman saccular epithelium, 8 of which are enriched in mouse hair cells, validating their hair cell-specific functions across vertebrates. We identified a suite of differentially expressed genes belonging to neurotransmission and

  1. Investigating the origins of nanostructural variations in differential ethnic hair types using X-ray scattering techniques.

    Science.gov (United States)

    Wade, M; Tucker, I; Cunningham, P; Skinner, R; Bell, F; Lyons, T; Patten, K; Gonzalez, L; Wess, T

    2013-10-01

    Human hair is a major determinant of visual ethnic differentiation. Although hair types are celebrated as part of our ethnic diversity, the approach to hair care has made the assumption that hair types are structurally and chemically similar. Although this is clearly not the case at the macroscopic level, the intervention of many hair treatments is at the nanoscopic and molecular levels. The purpose of the work presented here is to identify the main nanoscopic and molecular hierarchical differences across five different ethnic hair types from hair fibres taken exclusively from the scalp. These are Afro (subdivided into elastic 'rubber' and softer non-elastic 'soft'), Chinese, European and Mullato (mixed race). Small angle X-Ray scattering (SAXS) is a technique capable of resolving nanostructural variations in complex materials. Individual hair fibres from different ethnic hair types were used to investigate structural features found in common and also specific to each type. Simultaneous wide angle X-Ray scattering (WAXS) was used to analyse the submolecular level structure of the fibrous keratin present. The data sets from both techniques were analysed with principal component analysis (PCA) to identify underlying variables. Principal component analysis of both SAXS and WAXS data was shown to discriminate the scattering signal between different hair types. The X-ray scattering results show a common underlying keratin intermediate filament (KIF) structure. However, distinct differences were observed in the preferential orientation and intensity signal from the lipid component of the hair. In addition, differences were observed in the intensity distribution of the very low-angle sample-dependent diffuse scatter surrounding the 'beamstop.' The results indicate that the fibrous keratin scaffold remains consistent between ethnic hair types. The hierarchies made by these may be modulated by variation in the content of keratin-associated proteins (KAPs) and lipids that

  2. Unleashing the potential of the root hair cell as a single plant cell type model in root systems biology

    Directory of Open Access Journals (Sweden)

    Zhenzhen eQiao

    2013-11-01

    Full Text Available Plant root is an organ composed of multiple cell types with different functions. This multicellular complexity limits our understanding of root biology because –omics studies performed at the level of the entire root reflect the average responses of all cells composing the organ. To overcome this difficulty and allow a more comprehensive understanding of root cell biology, an approach is needed that would focus on one single cell type in the plant root. Because of its biological functions (i.e. uptake of water and various nutrients; primary site of infection by nitrogen-fixing bacteria in legumes, the root hair cell is an attractive single cell model to study root cell response to various stresses and treatments. To fully study their biology, we have recently optimized procedures in obtaining root hair cell samples. We culture the plants using an ultrasound aeroponic system maximizing root hair cell density on the entire root systems and allowing the homogeneous treatment of the root system. We then isolate the root hair cells in liquid nitrogen. Isolated root hair yields could be up to 800 to 1000 mg of plant cells from 60 root systems. Using soybean as a model, the purity of the root hair was assessed by comparing the expression level of genes previously identified as soybean root hair specific between preparations of isolated root hair cells and stripped roots, roots devoid in root hairs. Enlarging our tests to include other plant species, our results support the isolation of large quantities of highly purified root hair cells which is compatible with a systems biology approach.

  3. Artifactual voltage response recorded from hair cells with patch-clamp amplifiers.

    Science.gov (United States)

    Masetto, S; Weng, T; Valli, P; Correia, M J

    1999-06-23

    Patch-clamp amplifiers (PCAs) are commonly used to characterize voltage- and current-clamp responses in the same cell. However, the cell membrane voltage response can be severely distorted by PCAs working in the current-clamp mode. Here we compare the voltage response of pigeon semicircular canal hair cells in situ, recorded with two different PCAs, and with a classic microelectrode bridge amplifier (BA). We found that the voltage response of hair cells recorded with PCAs differed significantly from that recorded with the BA. The true hair cell membrane voltage response to positive current steps was characterized by a strongly damped oscillation, whose frequency and duration depended on hair cell location in the sensory crista ampullaris.

  4. Type I hair cell degeneration in the utricular macula of the waltzing guinea pig

    DEFF Research Database (Denmark)

    Severinsen, Stig A; Raarup, Merete Krog; Ulfendahl, Mats

    2008-01-01

    Waltzing guinea pigs are an inbred guinea pig strain with a congenital and progressive balance and hearing disorder. A unique rod-shaped structure is found in the type I vestibular hair cells, that traverses the cell in an axial direction, extending towards the basement membrane. The present study...... estimates the total number of utricular hair cells and supporting cells in waltzing guinea pigs and age-matched control animals using the optical fractionator method. Animals were divided into four age groups (1, 7, 49 and 343 day-old). The number of type I hair cells decreased by 20% in the 343 day......-old waltzing guinea pigs compared to age-matched controls and younger animals. Two-photon confocal laser scanning microscopy using antibodies against fimbrin and betaIII-tubulin showed that the rods were exclusive to type I hair cells. There was no significant change in the length of the filament rods with age...

  5. Alternative Splice Forms Influence Functions of Whirlin in Mechanosensory Hair Cell Stereocilia

    Directory of Open Access Journals (Sweden)

    Seham Ebrahim

    2016-05-01

    Full Text Available WHRN (DFNB31 mutations cause diverse hearing disorders: profound deafness (DFNB31 or variable hearing loss in Usher syndrome type II. The known role of WHRN in stereocilia elongation does not explain these different pathophysiologies. Using spontaneous and targeted Whrn mutants, we show that the major long (WHRN-L and short (WHRN-S isoforms of WHRN have distinct localizations within stereocilia and also across hair cell types. Lack of both isoforms causes abnormally short stereocilia and profound deafness and vestibular dysfunction. WHRN-S expression, however, is sufficient to maintain stereocilia bundle morphology and function in a subset of hair cells, resulting in some auditory response and no overt vestibular dysfunction. WHRN-S interacts with EPS8, and both are required at stereocilia tips for normal length regulation. WHRN-L localizes midway along the shorter stereocilia, at the level of inter-stereociliary links. We propose that differential isoform expression underlies the variable auditory and vestibular phenotypes associated with WHRN mutations.

  6. Alternative Splice Forms Influence Functions of Whirlin in Mechanosensory Hair Cell Stereocilia.

    Science.gov (United States)

    Ebrahim, Seham; Ingham, Neil J; Lewis, Morag A; Rogers, Michael J C; Cui, Runjia; Kachar, Bechara; Pass, Johanna C; Steel, Karen P

    2016-05-03

    WHRN (DFNB31) mutations cause diverse hearing disorders: profound deafness (DFNB31) or variable hearing loss in Usher syndrome type II. The known role of WHRN in stereocilia elongation does not explain these different pathophysiologies. Using spontaneous and targeted Whrn mutants, we show that the major long (WHRN-L) and short (WHRN-S) isoforms of WHRN have distinct localizations within stereocilia and also across hair cell types. Lack of both isoforms causes abnormally short stereocilia and profound deafness and vestibular dysfunction. WHRN-S expression, however, is sufficient to maintain stereocilia bundle morphology and function in a subset of hair cells, resulting in some auditory response and no overt vestibular dysfunction. WHRN-S interacts with EPS8, and both are required at stereocilia tips for normal length regulation. WHRN-L localizes midway along the shorter stereocilia, at the level of inter-stereociliary links. We propose that differential isoform expression underlies the variable auditory and vestibular phenotypes associated with WHRN mutations. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  7. ACh-induced hyperpolarization and decreased resistance in mammalian type II vestibular hair cells.

    Science.gov (United States)

    Poppi, Lauren A; Tabatabaee, Hessam; Drury, Hannah R; Jobling, Phillip; Callister, Robert J; Migliaccio, Americo A; Jordan, Paivi M; Holt, Joseph C; Rabbitt, Richard D; Lim, Rebecca; Brichta, Alan M

    2018-01-01

    In the mammalian vestibular periphery, electrical activation of the efferent vestibular system (EVS) has two effects on afferent activity: 1) it increases background afferent discharge and 2) decreases afferent sensitivity to rotational stimuli. Although the cellular mechanisms underlying these two contrasting afferent responses remain obscure, we postulated that the reduction in afferent sensitivity was attributed, in part, to the activation of α9- containing nicotinic acetylcholine (ACh) receptors (α9*nAChRs) and small-conductance potassium channels (SK) in vestibular type II hair cells, as demonstrated in the peripheral vestibular system of other vertebrates. To test this hypothesis, we examined the effects of the predominant EVS neurotransmitter ACh on vestibular type II hair cells from wild-type (wt) and α9-subunit nAChR knockout (α9 -/- ) mice. Immunostaining for choline acetyltransferase revealed there were no obvious gross morphological differences in the peripheral EVS innervation among any of these strains. ACh application onto wt type II hair cells, at resting potentials, produced a fast inward current followed by a slower outward current, resulting in membrane hyperpolarization and decreased membrane resistance. Hyperpolarization and decreased resistance were due to gating of SK channels. Consistent with activation of α9*nAChRs and SK channels, these ACh-sensitive currents were antagonized by the α9*nAChR blocker strychnine and SK blockers apamin and tamapin. Type II hair cells from α9 -/- mice, however, failed to respond to ACh at all. These results confirm the critical importance of α9nAChRs in efferent modulation of mammalian type II vestibular hair cells. Application of exogenous ACh reduces electrical impedance, thereby decreasing type II hair cell sensitivity. NEW & NOTEWORTHY Expression of α9 nicotinic subunit was crucial for fast cholinergic modulation of mammalian vestibular type II hair cells. These findings show a multifaceted

  8. Comparative study of human-induced pluripotent stem cells derived from bone marrow cells, hair keratinocytes, and skin fibroblasts.

    Science.gov (United States)

    Streckfuss-Bömeke, Katrin; Wolf, Frieder; Azizian, Azadeh; Stauske, Michael; Tiburcy, Malte; Wagner, Stefan; Hübscher, Daniela; Dressel, Ralf; Chen, Simin; Jende, Jörg; Wulf, Gerald; Lorenz, Verena; Schön, Michael P; Maier, Lars S; Zimmermann, Wolfram H; Hasenfuss, Gerd; Guan, Kaomei

    2013-09-01

    Induced pluripotent stem cells (iPSCs) provide a unique opportunity for the generation of patient-specific cells for use in disease modelling, drug screening, and regenerative medicine. The aim of this study was to compare human-induced pluripotent stem cells (hiPSCs) derived from different somatic cell sources regarding their generation efficiency and cardiac differentiation potential, and functionalities of cardiomyocytes. We generated hiPSCs from hair keratinocytes, bone marrow mesenchymal stem cells (MSCs), and skin fibroblasts by using two different virus systems. We show that MSCs and fibroblasts are more easily reprogrammed than keratinocytes. This corresponds to higher methylation levels of minimal promoter regions of the OCT4 and NANOG genes in keratinocytes than in MSCs and fibroblasts. The success rate and reprogramming efficiency was significantly higher by using the STEMCCA system than the OSNL system. All analysed hiPSCs are pluripotent and show phenotypical characteristics similar to human embryonic stem cells. We studied the cardiac differentiation efficiency of generated hiPSC lines (n = 24) and found that MSC-derived hiPSCs exhibited a significantly higher efficiency to spontaneously differentiate into beating cardiomyocytes when compared with keratinocyte-, and fibroblast-derived hiPSCs. There was no significant difference in the functionalities of the cardiomyocytes derived from hiPSCs with different origins, showing the presence of pacemaker-, atrial-, ventricular- and Purkinje-like cardiomyocytes, and exhibiting rhythmic Ca2+ transients and Ca2+ sparks in hiPSC-derived cardiomyocytes. Furthermore, spontaneously and synchronously beating and force-developing engineered heart tissues were generated. Human-induced pluripotent stem cells can be reprogrammed from all three somatic cell types, but with different efficiency. All analysed iPSCs can differentiate into cardiomyocytes, and the functionalities of cardiomyocytes derived from different cell

  9. Effect of histone deacetylase inhibitors trichostatin A and valproic acid on hair cell regeneration in zebrafish lateral line neuromasts

    Science.gov (United States)

    He, Yingzi; Cai, Chengfu; Tang, Dongmei; Sun, Shan; Li, Huawei

    2014-01-01

    In humans, auditory hair cells are not replaced when injured. Thus, cochlear hair cell loss causes progressive and permanent hearing loss. Conversely, non-mammalian vertebrates are capable of regenerating lost sensory hair cells. The zebrafish lateral line has numerous qualities that make it well-suited for studying hair cell development and regeneration. Histone deacetylase (HDAC) activity has been shown to have an important role in regenerative processes in vertebrates, but its function in hair cell regeneration in vivo is not fully understood. Here, we have examined the role of HDAC activity in hair cell regeneration in the zebrafish lateral line. We eliminated lateral line hair cells of 5-day post-fertilization larvae using neomycin and then treated the larvae with HDAC inhibitors. To assess hair cell regeneration, we used 5-bromo-2-deoxyuridine (BrdU) incorporation in zebrafish larvae to label mitotic cells after hair cell loss. We found that pharmacological inhibition of HDACs using trichostatin A (TSA) or valproic acid (VPA) increased histone acetylation in the regenerated neuromasts following neomycin-induced damage. We also showed that treatment with TSA or VPA decreased the number of supporting cells and regenerated hair cells in response to hair cell damage. Additionally, BrdU immunostaining and western blot analysis showed that TSA or VPA treatment caused a significant decrease in the percentage of S-phase cells and induced p21Cip1 and p27Kip1 expression, both of which are likely to explain the decrease in the amount of newly regenerated hair cells in treated embryos. Finally, we showed that HDAC inhibitors induced no observable cell death in neuromasts as measured by cleaved caspase-3 immunohistochemistry and western blot analysis. Taken together, our results demonstrate that HDAC activity has an important role in the regeneration of hair cells in the lateral line. PMID:25431550

  10. Effect of histone deacetylase inhibitors trichostatin A and valproic acid on hair cell regeneration in zebrafish lateral line neuromasts

    Directory of Open Access Journals (Sweden)

    Yingzi eHe

    2014-11-01

    Full Text Available In humans, auditory hair cells are not replaced when injured. Thus, cochlear hair cell loss causes progressive and permanent hearing loss. Conversely, nonmammalian vertebrates are capable of regenerating lost sensory hair cells. The zebrafish lateral line has numerous qualities that make it well suited for studying hair cell development and regeneration. Histone deacetylase (HDAC activity has been shown to have an important role in regenerative processes in vertebrates, but its function in hair cell regeneration in vivo is not fully understood. Here, we have examined the role of HDAC activity in hair cell regeneration in the zebrafish lateral line. We eliminated lateral line hair cells of 5-day post-fertilization larvae using neomycin and then treated the larvae with HDAC inhibitors. To assess hair cell regeneration, we used 5-bromo-2-deoxyuridine (BrdU incorporation in zebrafish larvae to label mitotic cells after hair cell loss. We found that pharmacological inhibition of HDACs using trichostatin A (TSA or valproic acid (VPA increased histone acetylation in the regenerated neuromasts following neomycin-induced damage. We also showed that treatment with TSA or VPA decreased the number of supporting cells and regenerated hair cells in response to hair cell damage. Additionally, BrdU immunostaining and western blot analysis showed that TSA or VPA treatment caused a significant decrease in the percentage of S-phase cells and induced p21Cip1 and p27Kip1 expression, both of which are likely to explain the decrease in the amount of newly regenerated hair cells in treated embryos. Finally, we showed that HDAC inhibitors induced no observable cell death in neuromasts as measured by cleaved caspase-3 immunohistochemistry and western blot analysis. Taken together, our results demonstrate that HDAC activity has an important role in the regeneration of hair cells in the lateral line.

  11. Diphtheria Toxin-Induced Cell Death Triggers Wnt-Dependent Hair Cell Regeneration in Neonatal Mice.

    Science.gov (United States)

    Hu, Lingxiang; Lu, Jingrong; Chiang, Hao; Wu, Hao; Edge, Albert S B; Shi, Fuxin

    2016-09-07

    Cochlear hair cells (HCs), the sensory cells that respond to sound, do not regenerate after damage in adult mammals, and their loss is a major cause of deafness. Here we show that HC regeneration in newborn mouse ears occurred spontaneously when the original cells were ablated by treatment with diphtheria toxin (DT) in ears that had been engineered to overexpress the DT receptor, but was not detectable when HCs were ablated in vivo by the aminoglycoside antibiotic neomycin. A variety of Wnts (Wnt1, Wnt2, Wnt2b, Wnt4, Wnt5a, Wnt7b, Wnt9a, Wnt9b, and Wnt11) and Wnt pathway component Krm2 were upregulated after DT damage. Nuclear β-catenin was upregulated in HCs and supporting cells of the DT-damaged cochlea. Pharmacological inhibition of Wnt decreased spontaneous regeneration, confirming a role of Wnt signaling in HC regeneration. Inhibition of Notch signaling further potentiated supporting cell proliferation and HC differentiation that occurred spontaneously. The absence of new HCs in the neomycin ears was correlated to less robust Wnt pathway activation, but the ears subjected to neomycin treatment nonetheless showed increased cell division and HC differentiation after subsequent forced upregulation of β-catenin. These studies suggest, first, that Wnt signaling plays a key role in regeneration, and, second, that the outcome of a regenerative response to damage in the newborn cochlea is determined by reaching a threshold level of Wnt signaling rather than its complete absence or presence. Sensory HCs of the inner ear do not regenerate in the adult, and their loss is a major cause of deafness. We found that HCs regenerated spontaneously in the newborn mouse after diphtheria toxin (DT)-induced, but not neomycin-induced, HC death. Regeneration depended on activation of Wnt signaling, and regeneration in DT-treated ears correlated to a higher level of Wnt activation than occurred in nonregenerating neomycin-treated ears. This is significant because insufficient

  12. Low density of membrane particles in auditory hair cells of lizards and birds suggests an absence of somatic motility.

    Science.gov (United States)

    Köppl, Christine; Forge, Andrew; Manley, Geoffrey A

    2004-11-08

    Hair cells are the mechanoreceptive cells of the vertebrate lateral line and inner ear. In addition to their sensory function, hair cells display motility and thus themselves generate mechanical energy, which is thought to enhance sensitivity. Two principal cellular mechanism are known that can mediate hair-cell motility in vitro. One of these is based on voltage-dependent changes of an intramembrane protein and has so far been demonstrated only in outer hair cells of the mammalian cochlea. Correlated with this, the cell membranes of outer hair cells carry an extreme density of embedded particles, as revealed by freeze fracturing. The present study explored the possibility of membrane-based motility in hair cells of nonmammals, by determining their density of intramembrane particles. Replicas of freeze-fractured membrane were prepared from auditory hair cells of a lizard, the Tokay gecko, and a bird, the barn owl. These species were chosen because of independent evidence for active cochlear mechanics, in the form of spontaneous otoacoustic emissions. For quantitative comparison, mammalian inner and outer hair cells, as well as vestibular hair, cells were reevaluated. Lizard and bird hair cells displayed median densities of 2,360 and 1,880 intramembrane particles/microm2, respectively. This was not significantly different from the densities in vestibular and mammalian inner hair cells; however, it was about half the density in of mammalian outer hair cells. This suggests that nonmammalian hair cells do not possess high densities of motor protein in their membranes and are thus unlikely to be capable of somatic motility. 2004 Wiley-Liss, Inc.

  13. Distribution and time course of hair cell regeneration in the pigeon utricle

    Science.gov (United States)

    Dye, B. J.; Frank, T. C.; Newlands, S. D.; Dickman, J. D.

    1999-01-01

    Vestibular and cochlear regeneration following ototoxic insult from aminoglycoside antibiotics has been well documented, particularly in birds. In the present study, intraotic application of a 2 mg streptomycin paste was used to achieve complete vestibular hair cell destruction in pigeons (Columba livia) while preserving regenerative ability. Scanning electron microscopy was used to quantify hair cell density longitudinally during regeneration in three different utricular macula locations, including the striola, central and peripheral regions. The utricular epithelium was void of stereocilia (indicating hair cell loss) at 4 days after intraotic treatment with streptomycin. At 2 weeks the stereocilia began to appear randomly and mostly in an immature form. However, when present most kinocilia were polarized toward the developing striola. Initially, regeneration occurred more rapidly in the central and peripheral regions of the utricle as compared to the striola. As regeneration proceeded from 2 to 12 weeks, hair cell density in the striola region equaled the density noted in the central and peripheral regions. At 24 weeks, hair cell density of the central and peripheral regions was equal to normal values, however the striola region had a slightly greater hair cell density than that observed for normal animals.

  14. The Hair Follicle: An Underutilized Source of Cells and Materials for Regenerative Medicine.

    Science.gov (United States)

    Kiani, Mehrdad T; Higgins, Claire A; Almquist, Benjamin D

    2018-04-09

    The hair follicle is one of only two structures within the adult body that selectively degenerates and regenerates, making it an intriguing organ to study and use for regenerative medicine. Hair follicles have been shown to influence wound healing, angiogenesis, neurogenesis, and harbor distinct populations of stem cells; this has led to cells from the follicle being used in clinical trials for tendinosis and chronic ulcers. In addition, keratin produced by the follicle in the form of a hair fiber provides an abundant source of biomaterials for regenerative medicine. In this review, we provide an overview of the structure of a hair follicle, explain the role of the follicle in regulating the microenvironment of skin and the impact on wound healing, explore individual cell types of interest for regenerative medicine, and cover several applications of keratin-based biomaterials.

  15. Making sense of Wnt signaling – linking hair cell regeneration to development

    Directory of Open Access Journals (Sweden)

    Lina eJansson

    2015-03-01

    Full Text Available Wnt signaling is a highly conserved pathway crucial for development and homeostasis of multicellular organisms. Secreted Wnt ligands bind Frizzled receptors to regulate diverse processes such as axis patterning, cell division, and cell fate specification. They also serve to govern self-renewal of somatic stem cells in several adult tissues. The complexity of the pathway can be attributed to the myriad of Wnt and Frizzled combinations as well as its diverse context-dependent functions. In the developing mouse inner ear, Wnt signaling plays diverse roles, including specification of the otic placode and patterning of the otic vesicle. At later stages, its activity governs sensory hair cell specification, cell cycle regulation, and hair cell orientation. In regenerating sensory organs from non-mammalian species, Wnt signaling can also regulate the extent of proliferative hair cell regeneration. This review describes the current knowledge of the roles of Wnt signaling and Wnt-responsive cells in hair cell development and regeneration. We also discuss possible future directions and the potential application and limitation of Wnt signaling in augmenting hair cell regeneration.

  16. Human hair follicle pluripotent stem (hfPS) cells promote regeneration of peripheral-nerve injury: an advantageous alternative to ES and iPS cells.

    Science.gov (United States)

    Amoh, Yasuyuki; Kanoh, Maho; Niiyama, Shiro; Hamada, Yuko; Kawahara, Katsumasa; Sato, Yuichi; Hoffman, Robert M; Katsuoka, Kensei

    2009-08-01

    The optimal source of stem cells for regenerative medicine is a major question. Embryonic stem (ES) cells have shown promise for pluripotency but have ethical issues and potential to form teratomas. Pluripotent stem cells have been produced from skin cells by either viral-, plasmid- or transposon-mediated gene transfer. These stem cells have been termed induced pluripotent stem cells or iPS cells. iPS cells may also have malignant potential and are inefficiently produced. Embryonic stem cells may not be suited for individualized therapy, since they can undergo immunologic rejection. To address these fundamental problems, our group is developing hair follicle pluripotent stem (hfPS) cells. Our previous studies have shown that mouse hfPS cells can differentiate to neurons, glial cells in vitro, and other cell types, and can promote nerve and spinal cord regeneration in vivo. hfPS cells are located above the hair follicle bulge in what we have termed the hfPS cell area (hfPSA) and are nestin positive and keratin 15 (K-15) negative. Human hfPS cells can also differentiate into neurons, glia, keratinocytes, smooth muscle cells, and melanocytes in vitro. In the present study, human hfPS cells were transplanted in the severed sciatic nerve of the mouse where they differentiated into glial fibrillary-acidic-protein (GFAP)-positive Schwann cells and promoted the recovery of pre-existing axons, leading to nerve generation. The regenerated nerve recovered function and, upon electrical stimulation, contracted the gastrocnemius muscle. The hfPS cells can be readily isolated from the human scalp, thereby providing an accessible, autologous and safe source of stem cells for regenerative medicine that have important advantages over ES or iPS cells. (c) 2009 Wiley-Liss, Inc.

  17. Cytoplasm localization of aminopeptidase M1 and its functional activity in root hair cells and BY-2 cells.

    Science.gov (United States)

    Lee, Ok Ran; Cho, Hyung-Taeg

    2012-12-01

    Aminopeptidase M1 (APM1) was the first M1 metallopeptidase family member identified in Arabidopsis, isolated by its affinity for the auxin transport inhibitor N-1-naphthylphthalamic acid (NPA). A loss-of-function mutation showed various developmental defects in cell division and auxin transport. APM1 was shown to be localized in endomembrane structures, the cytoplasm, and the plasma membrane. These previous results suggested that APM1 has diverse functional roles in different cell and tissue types. Here we report that APM1 localized to the cytoplasm, and its over-expression in the root hair cell caused longer root hair phenotypes. Treatment of aminopeptidase inhibitors caused internalization of auxin efflux PIN-FORMED proteins in root hair cells and suppressed short root hair phenotype of PIN3 overexpression line (PIN3ox). APM1 also localized to the cytoplasm in tobacco BY-2 cells, its over-expression had little effect on auxin transport in these cells.

  18. Monitoring intracellular calcium ion dynamics in hair cell populations with Fluo-4 AM.

    Directory of Open Access Journals (Sweden)

    Kateri J Spinelli

    Full Text Available We optimized Fluo-4 AM loading of chicken cochlea to report hair-bundle Ca(2+ signals in populations of hair cells. The bundle Ca(2+ signal reported the physiological state of the bundle and cell; extruding cells had very high bundle Fluo-4 fluorescence, cells with intact bundles and tip links had intermediate fluorescence, and damaged cells with broken tip links had low fluorescence. Moreover, Fluo-4 fluorescence in the bundle correlated with Ca(2+ entry through transduction channels; mechanically activating transduction channels increased the Fluo-4 signal, while breaking tip links with Ca(2+ chelators or blocking Ca(2+ entry through transduction channels each caused bundle and cell-body Fluo-4 fluorescence to decrease. These results show that when tip links break, bundle and soma Ca(2+ decrease, which could serve to stimulate the hair cell's tip-link regeneration process. Measurement of bundle Ca(2+ with Fluo-4 AM is therefore a simple method for assessing mechanotransduction in hair cells and permits an increased understanding of the interplay of tip links, transduction channels, and Ca(2+ signaling in the hair cell.

  19. Zebrafish Models for the Mechanosensory Hair Cell Dysfunction in Usher Syndrome 3 Reveal That Clarin-1 Is an Essential Hair Bundle Protein.

    Science.gov (United States)

    Gopal, Suhasini R; Chen, Daniel H-C; Chou, Shih-Wei; Zang, Jingjing; Neuhauss, Stephan C F; Stepanyan, Ruben; McDermott, Brian M; Alagramam, Kumar N

    2015-07-15

    Usher syndrome type III (USH3) is characterized by progressive loss of hearing and vision, and varying degrees of vestibular dysfunction. It is caused by mutations that affect the human clarin-1 protein (hCLRN1), a member of the tetraspanin protein family. The missense mutation CLRN1(N48K), which affects a conserved N-glycosylation site in hCLRN1, is a common causative USH3 mutation among Ashkenazi Jews. The affected individuals hear at birth but lose that function over time. Here, we developed an animal model system using zebrafish transgenesis and gene targeting to provide an explanation for this phenotype. Immunolabeling demonstrated that Clrn1 localized to the hair cell bundles (hair bundles). The clrn1 mutants generated by zinc finger nucleases displayed aberrant hair bundle morphology with diminished function. Two transgenic zebrafish that express either hCLRN1 or hCLRN1(N48K) in hair cells were produced to examine the subcellular localization patterns of wild-type and mutant human proteins. hCLRN1 localized to the hair bundles similarly to zebrafish Clrn1; in contrast, hCLRN1(N48K) largely mislocalized to the cell body with a small amount reaching the hair bundle. We propose that this small amount of hCLRN1(N48K) in the hair bundle provides clarin-1-mediated function during the early stages of life; however, the presence of hCLRN1(N48K) in the hair bundle diminishes over time because of intracellular degradation of the mutant protein, leading to progressive loss of hair bundle integrity and hair cell function. These findings and genetic tools provide an understanding and path forward to identify therapies to mitigate hearing loss linked to the CLRN1 mutation. Mutations in the clarin-1 gene affect eye and ear function in humans. Individuals with the CLRN1(N48K) mutation are born able to hear but lose that function over time. Here, we develop an animal model system using zebrafish transgenesis and gene targeting to provide an explanation for this phenotype

  20. Minoxidil Promotes Hair Growth through Stimulation of Growth Factor Release from Adipose-Derived Stem Cells

    Directory of Open Access Journals (Sweden)

    Nahyun Choi

    2018-02-01

    Full Text Available Minoxidil directly promotes hair growth via the stimulation of dermal papilla (DP and epithelial cells. Alternatively, there is little evidence for indirect promotion of hair growth via stimulation of adipose-derived stem cells (ASCs. We investigated whether minoxidil stimulates ASCs and if increased growth factor secretion by ASCs facilitates minoxidil-induced hair growth. Telogen-to-anagen induction was examined in mice. Cultured DP cells and vibrissae hair follicle organ cultures were used to further examine the underlying mechanisms. Subcutaneous injection of minoxidil-treated ASCs accelerated telogen-to-anagen transition in mice, and increased hair weight at day 14 post-injection. Minoxidil did not alter ASC proliferation, but increased migration and tube formation. Minoxidil also increased the secretion of growth factors from ASCs, including chemokine (C-X-C motif ligand 1 (CXCL1, platelet-derived endothelial cell growth factor (PD-ECGF, and platelet-derived growth factor-C (PDGF-C. Minoxidil increased extracellular signal–regulated kinases 1/2 (ERK1/2 phosphorylation, and concomitant upregulation of PD-ECGF and PDGF-C mRNA levels were attenuated by an ERK inhibitor. Subcutaneous injection of CXCL1, PD-ECGF, or PDGF-C enhanced anagen induction in mice, and both CXCL1 and PDGF-C increased hair length in ex vivo organ culture. Treatment with CXCL1, PD-ECGF, or PDGF-C also increased the proliferation index in DP cells. Finally, topical application of CXCL1, PD-ECGF, or PDGF-C with 2% minoxidil enhanced anagen induction when compared to minoxidil alone. Minoxidil stimulates ASC motility and increases paracrine growth factor signaling. Minoxidil-stimulated secretion of growth factors by ASCs may enhance hair growth by promoting DP proliferation. Therefore, minoxidil can be used as an ASC preconditioning agent for hair regeneration.

  1. Minoxidil Promotes Hair Growth through Stimulation of Growth Factor Release from Adipose-Derived Stem Cells

    Science.gov (United States)

    Choi, Nahyun; Shin, Soyoung; Song, Sun U.; Sung, Jong-Hyuk

    2018-01-01

    Minoxidil directly promotes hair growth via the stimulation of dermal papilla (DP) and epithelial cells. Alternatively, there is little evidence for indirect promotion of hair growth via stimulation of adipose-derived stem cells (ASCs). We investigated whether minoxidil stimulates ASCs and if increased growth factor secretion by ASCs facilitates minoxidil-induced hair growth. Telogen-to-anagen induction was examined in mice. Cultured DP cells and vibrissae hair follicle organ cultures were used to further examine the underlying mechanisms. Subcutaneous injection of minoxidil-treated ASCs accelerated telogen-to-anagen transition in mice, and increased hair weight at day 14 post-injection. Minoxidil did not alter ASC proliferation, but increased migration and tube formation. Minoxidil also increased the secretion of growth factors from ASCs, including chemokine (C-X-C motif) ligand 1 (CXCL1), platelet-derived endothelial cell growth factor (PD-ECGF), and platelet-derived growth factor-C (PDGF-C). Minoxidil increased extracellular signal–regulated kinases 1/2 (ERK1/2) phosphorylation, and concomitant upregulation of PD-ECGF and PDGF-C mRNA levels were attenuated by an ERK inhibitor. Subcutaneous injection of CXCL1, PD-ECGF, or PDGF-C enhanced anagen induction in mice, and both CXCL1 and PDGF-C increased hair length in ex vivo organ culture. Treatment with CXCL1, PD-ECGF, or PDGF-C also increased the proliferation index in DP cells. Finally, topical application of CXCL1, PD-ECGF, or PDGF-C with 2% minoxidil enhanced anagen induction when compared to minoxidil alone. Minoxidil stimulates ASC motility and increases paracrine growth factor signaling. Minoxidil-stimulated secretion of growth factors by ASCs may enhance hair growth by promoting DP proliferation. Therefore, minoxidil can be used as an ASC preconditioning agent for hair regeneration. PMID:29495622

  2. Protective effects of edaravone against cisplatin-induced hair cell damage in zebrafish.

    Science.gov (United States)

    Hong, Seok Jin; Im, Gi Jung; Chang, Jiwon; Chae, Sung Won; Lee, Seung Hoon; Kwon, Soon Young; Jung, Hak Hyun; Chung, Ah Young; Park, Hae Chul; Choi, June

    2013-06-01

    Edaravone is known to have a potent free radical scavenging effect. The objective of the present study was to evaluate the effects of edaravone on cisplatin-induced ototoxicity in transgenic zebrafish (Brn3C: EGFP). Five day post-fertilization zebrafish larvae were exposed to 1000 μM cisplatin and 50 μM, 100 μM, 250 μM, 500 μM, 750 μM, and 1000 μM concentrations of edaravone for 4h. Hair cells within neuromasts of the supraorbital (SO1 and SO2), otic (O1), and occipital (OC1) lateral lines were analyzed by fluorescence microscopy and confocal microscopy (n=10). Hair cell survival was calculated as a percentage of the hair cells in the control group that were not exposed to cisplatin. Ultrastructural changes were evaluated using scanning electron microscopy and transmission electron microscopy. Edaravone protected cisplatin-induced hair cell loss of neuromasts (edaravone 750 μM: 8.7 ± 1.5 cells, cisplatin 1000 μM only: 3.7 ± 0.9 cells; n=10, pedaravone for 4h. Edaravone attenuated cisplatin-induced hair cell damage in zebrafish. The results of the current study suggest that cisplatin induces apoptosis, and the apoptotic cell death can be prevented by treatment with edaravone in zebrafish. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  3. Hair cell counts in a rat model of sound damage: Effects of tissue preparation & identification of regions of hair cell loss.

    Science.gov (United States)

    Neal, Christopher; Kennon-McGill, Stefanie; Freemyer, Andrea; Shum, Axel; Staecker, Hinrich; Durham, Dianne

    2015-10-01

    Exposure to intense sound can damage or kill cochlear hair cells (HC). This loss of input typically manifests as noise induced hearing loss, but it can also be involved in the initiation of other auditory disorders such as tinnitus or hyperacusis. In this study we quantify changes in HC number following exposure to one of four sound damage paradigms. We exposed adult, anesthetized Long-Evans rats to a unilateral 16 kHz pure tone that varied in intensity (114 dB or 118 dB) and duration (1, 2, or 4 h) and sacrificed animals 2-4 weeks later. We compared two different methods of tissue preparation, plastic embedding/sectioning and whole mount dissection, for quantifying hair cell loss as a function of frequency. We found that the two methods of tissue preparation produced largely comparable cochleograms, with whole mount dissections allowing a more rapid evaluation of hair cell number. Both inner and outer hair cell loss was observed throughout the length of the cochlea irrespective of sound damage paradigm. Inner HC loss was either equal to or greater than outer HC loss. Increasing the duration of sound exposures resulted in more severe HC loss, which included all HC lesions observed in an analogous shorter duration exposure. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Re-Emergent Inhibition of Cochlear Inner Hair Cells in a Mouse Model of Hearing Loss.

    Science.gov (United States)

    Zachary, Stephen Paul; Fuchs, Paul Albert

    2015-07-01

    Hearing loss among the elderly correlates with diminished social, mental, and physical health. Age-related cochlear cell death does occur, but growing anatomical evidence suggests that synaptic rearrangements on sensory hair cells also contribute to auditory functional decline. Here we present voltage-clamp recordings from inner hair cells of the C57BL/6J mouse model of age-related hearing loss, which reveal that cholinergic synaptic inputs re-emerge during aging. These efferents are functionally inhibitory, using the same ionic mechanisms as do efferent contacts present transiently before the developmental onset of hearing. The strength of efferent inhibition of inner hair cells increases with hearing threshold elevation. These data indicate that the aged cochlea regains features of the developing cochlea and that efferent inhibition of the primary receptors of the auditory system re-emerges with hearing impairment. Synaptic changes in the auditory periphery are increasingly recognized as important factors in hearing loss. To date, anatomical work has described the loss of afferent contacts from cochlear hair cells. However, relatively little is known about the efferent innervation of the cochlea during hearing loss. We performed intracellular recordings from mouse inner hair cells across the lifespan and show that efferent innervation of inner hair cells arises in parallel with the loss of afferent contacts and elevated hearing threshold during aging. These efferent neurons inhibit inner hair cells, raising the possibility that they play a role in the progression of age-related hearing loss. Copyright © 2015 the authors 0270-6474/15/359701-06$15.00/0.

  5. Mild perinatal adversities moderate the association between maternal harsh parenting and hair cortisol: Evidence for differential susceptibility.

    Science.gov (United States)

    Windhorst, Dafna A; Rippe, Ralph C A; Mileva-Seitz, Viara R; Verhulst, Frank C; Jaddoe, Vincent W V; Noppe, Gerard; van Rossum, Elisabeth F C; van den Akker, Erica L T; Tiemeier, Henning; van IJzendoorn, Marinus H; Bakermans-Kranenburg, Marian J

    2017-04-01

    It has been shown that following exposure to mild perinatal adversity, children have greater susceptibility to both the negative and positive aspects of their subsequent environment. In a large population-based cohort study (N = 1,776), we investigated whether mild perinatal adversity moderated the association between maternal harsh parenting and children's hair cortisol levels, a biomarker of chronic stress. Mild perinatal adversity was defined as late preterm birth (gestational age at birth of 34-37 weeks, 6 days) or small for gestational age (birth weight between the 2.5th and 10th percentile for full term gestational age). Harsh parenting was assessed by maternal self-report at 3 years. Children's hair cortisol concentrations were measured from hair samples collected at age 6. There were no significant bivariate associations between mild perinatal adversities and harsh parenting and hair cortisol. However, mild perinatal adversities moderated the association between maternal harsh parenting and hair cortisol levels. Children with mild perinatal adversity had lower cortisol levels if parented more harshly and higher cortisol levels in the absence of harsh parenting than children who did not experience mild perinatal adversity. These results provide further evidence that mild perinatal adversity is a potential marker of differential susceptibility to environmental influences. © 2017 Wiley Periodicals, Inc.

  6. Molecular Conversations and the Development of the Hair Follicle and Basal Cell Carcinoma

    OpenAIRE

    Harris, Pamela Jo; Takebe, Naoko; Ivy, S. Percy

    2010-01-01

    The understanding of the anatomy and development of fetal and adult hair follicles and molecular study of the major embryonic pathways that regulate the hair follicle have led to exciting discoveries concerning the development of basal cell carcinoma (BCC). These studies have shed light on the major roles of Sonic hedgehog (Shh) signaling and its interactions with the insulin-like growth factor (IGF) axis in BCC development. New work, for example, explores a link between Shh signaling and IGF...

  7. Differential correlations between maternal hair levels of tobacco and alcohol with fetal growth restriction clinical subtypes.

    Science.gov (United States)

    Sabra, Sally; Malmqvist, Ebba; Almeida, Laura; Gratacos, Eduard; Gomez Roig, Maria Dolores

    2018-08-01

    Maternal exposure to tobacco and alcohol is a known cause, among others, for fetal growth restriction (FGR). Clinically, FGR can be subclassified into two forms: intrauterine growth restriction (IUGR) and small for gestational age (SGA), based on the severity of the growth retardation, and abnormal uterine artery Doppler or cerebro-placental ratio. This study aimed at investigating any differential correlation between maternal exposures to these toxins with the two clinical forms of FGR. Therefore, a case-control study was conducted in Barcelona, Spain. Sixty-four FGR subjects, who were further subclassified into IUGR (n = 36) and SGA (n = 28), and 89 subjects matched appropriate-for-gestational age (AGA), were included. The levels of nicotine (NIC) and ethyl glucuronide (EtG), biomarkers of tobacco and alcohol exposure, respectively, were assessed in the maternal hair in the third trimester. Our analysis showed 65% of the pregnant women consumed alcohol, 25% smoked, and 19% did both. The odds ratios (ORs) of IUGR were 21 times versus 14 times for being SGA with maternal heavy smoking, while with alcohol consumption the ORs for IUGR were 22 times versus 37 times for the SGA group. The differential correlations between these toxins with the two subtypes of FGR suggest different mechanisms influencing fetal weight. Our alarming data of alcohol consumption during pregnancy should be considered for further confirmation among Spanish women. Copyright © 2018 Elsevier Inc. All rights reserved.

  8. Concurrent gradients of ribbon volume and AMPA-receptor patch volume in cochlear afferent synapses on gerbil inner hair cells.

    Science.gov (United States)

    Zhang, Lichun; Engler, Sina; Koepcke, Lena; Steenken, Friederike; Köppl, Christine

    2018-07-01

    The Mongolian gerbil is a classic animal model for age-related hearing loss. As a prerequisite for studying age-related changes, we characterized cochlear afferent synaptic morphology in young adult gerbils, using immunolabeling and quantitative analysis of confocal microscopic images. Cochlear wholemounts were triple-labeled with a hair-cell marker, a marker of presynaptic ribbons, and a marker of postsynaptic AMPA-type glutamate receptors. Seven cochlear positions covering an equivalent frequency range from 0.5 - 32 kHz were evaluated. The spatial positions of synapses were determined in a coordinate system with reference to their individual inner hair cell. Synapse numbers confirmed previous reports for gerbils (on average, 20-22 afferents per inner hair cell). The volumes of presynaptic ribbons and postsynaptic glutamate receptor patches were positively correlated: larger ribbons associated with larger receptor patches and smaller ribbons with smaller patches. Furthermore, the volumes of both presynaptic ribbons and postsynaptic receptor patches co-varied along the modiolar-pillar and the longitudinal axes of their hair cell. The gradients in ribbon volume are consistent with previous findings in cat, guinea pig, mouse and rat and further support a role in differentiating the physiological properties of type I afferents. However, the positive correlation between the volumes of pre- and postsynaptic elements in the gerbil is different to the opposing gradients found in the mouse, suggesting species-specific differences in the postsynaptic AMPA receptors that are unrelated to the fundamental classes of type I afferents. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Characterization of the Transcriptomes of Lgr5+ Hair Cell Progenitors and Lgr5- Supporting Cells in the Mouse Cochlea.

    Science.gov (United States)

    Cheng, Cheng; Guo, Luo; Lu, Ling; Xu, Xiaochen; Zhang, ShaSha; Gao, Junyan; Waqas, Muhammad; Zhu, Chengwen; Chen, Yan; Zhang, Xiaoli; Xuan, Chuanying; Gao, Xia; Tang, Mingliang; Chen, Fangyi; Shi, Haibo; Li, Huawei; Chai, Renjie

    2017-01-01

    Cochlear supporting cells (SCs) have been shown to be a promising resource for hair cell (HC) regeneration in the neonatal mouse cochlea. Previous studies have reported that Lgr5+ SCs can regenerate HCs both in vitro and in vivo and thus are considered to be inner ear progenitor cells. Lgr5+ progenitors are able to regenerate more HCs than Lgr5- SCs, and it is important to understand the mechanism behind the proliferation and HC regeneration of these progenitors. Here, we isolated Lgr5+ progenitors and Lgr5- SCs from Lgr5-EGFP-CreERT2/Sox2-CreERT2/Rosa26-tdTomato mice via flow cytometry. As expected, we found that Lgr5+ progenitors had significantly higher proliferation and HC regeneration ability than Lgr5- SCs. Next, we performed RNA-Seq to determine the gene expression profiles of Lgr5+ progenitors and Lgr5- SCs. We analyzed the genes that were enriched and differentially expressed in Lgr5+ progenitors and Lgr5- SCs, and we found 8 cell cycle genes, 9 transcription factors, and 24 cell signaling pathway genes that were uniquely expressed in one population but not the other. Last, we made a protein-protein interaction network to further analyze the role of these differentially expressed genes. In conclusion, we present a set of genes that might regulate the proliferation and HC regeneration ability of Lgr5+ progenitors, and these might serve as potential new therapeutic targets for HC regeneration.

  10. Characterization of the Transcriptomes of Lgr5+ Hair Cell Progenitors and Lgr5- Supporting Cells in the Mouse Cochlea

    Directory of Open Access Journals (Sweden)

    Haibo Shi

    2017-04-01

    Full Text Available Cochlear supporting cells (SCs have been shown to be a promising resource for hair cell (HC regeneration in the neonatal mouse cochlea. Previous studies have reported that Lgr5+ SCs can regenerate HCs both in vitro and in vivo and thus are considered to be inner ear progenitor cells. Lgr5+ progenitors are able to regenerate more HCs than Lgr5- SCs, and it is important to understand the mechanism behind the proliferation and HC regeneration of these progenitors. Here, we isolated Lgr5+ progenitors and Lgr5- SCs from Lgr5-EGFP-CreERT2/Sox2-CreERT2/Rosa26-tdTomato mice via flow cytometry. As expected, we found that Lgr5+ progenitors had significantly higher proliferation and HC regeneration ability than Lgr5- SCs. Next, we performed RNA-Seq to determine the gene expression profiles of Lgr5+ progenitors and Lgr5- SCs. We analyzed the genes that were enriched and differentially expressed in Lgr5+ progenitors and Lgr5- SCs, and we found 8 cell cycle genes, 9 transcription factors, and 24 cell signaling pathway genes that were uniquely expressed in one population but not the other. Last, we made a protein–protein interaction network to further analyze the role of these differentially expressed genes. In conclusion, we present a set of genes that might regulate the proliferation and HC regeneration ability of Lgr5+ progenitors, and these might serve as potential new therapeutic targets for HC regeneration.

  11. Characterization of the Transcriptomes of Lgr5+ Hair Cell Progenitors and Lgr5- Supporting Cells in the Mouse Cochlea

    Science.gov (United States)

    Cheng, Cheng; Guo, Luo; Lu, Ling; Xu, Xiaochen; Zhang, ShaSha; Gao, Junyan; Waqas, Muhammad; Zhu, Chengwen; Chen, Yan; Zhang, Xiaoli; Xuan, Chuanying; Gao, Xia; Tang, Mingliang; Chen, Fangyi; Shi, Haibo; Li, Huawei; Chai, Renjie

    2017-01-01

    Cochlear supporting cells (SCs) have been shown to be a promising resource for hair cell (HC) regeneration in the neonatal mouse cochlea. Previous studies have reported that Lgr5+ SCs can regenerate HCs both in vitro and in vivo and thus are considered to be inner ear progenitor cells. Lgr5+ progenitors are able to regenerate more HCs than Lgr5- SCs, and it is important to understand the mechanism behind the proliferation and HC regeneration of these progenitors. Here, we isolated Lgr5+ progenitors and Lgr5- SCs from Lgr5-EGFP-CreERT2/Sox2-CreERT2/Rosa26-tdTomato mice via flow cytometry. As expected, we found that Lgr5+ progenitors had significantly higher proliferation and HC regeneration ability than Lgr5- SCs. Next, we performed RNA-Seq to determine the gene expression profiles of Lgr5+ progenitors and Lgr5- SCs. We analyzed the genes that were enriched and differentially expressed in Lgr5+ progenitors and Lgr5- SCs, and we found 8 cell cycle genes, 9 transcription factors, and 24 cell signaling pathway genes that were uniquely expressed in one population but not the other. Last, we made a protein–protein interaction network to further analyze the role of these differentially expressed genes. In conclusion, we present a set of genes that might regulate the proliferation and HC regeneration ability of Lgr5+ progenitors, and these might serve as potential new therapeutic targets for HC regeneration. PMID:28491023

  12. Progressive hearing loss and degeneration of hair cell stereocilia in taperin gene knockout mice

    International Nuclear Information System (INIS)

    Chen, Mo; Wang, Qin; Zhu, Gang-Hua; Hu, Peng; Zhou, Yuan; Wang, Tian; Lai, Ruo-Sha; Xiao, Zi-An; Xie, Ding-Hua

    2016-01-01

    The TPRN gene encodes taperin, which is prominently present at the taper region of hair cell stereocilia. Mutations in TPRN have been reported to cause autosomal recessive nonsyndromic deafness 79(DFNB 79). To investigate the role of taperin in pathogenesis of hearing loss, we generated TPRN knockout mice using TALEN technique. Sanger sequencing confirmed an 11 bp deletion at nucleotide 177–187 in exon 1 of TPRN, which results in a truncated form of taperin protein. Heterozygous TPRN +/− mice showed apparently normal auditory phenotypes to their wide-type (WT) littermates. Homozygous TPRN −/− mice exhibited progressive sensorineural hearing loss as reflected by auditory brainstem response to both click and tone burst stimuli at postnatal days 15 (P15), 30 (P30), and 60 (P60). Alex Fluor-594 phalloidin labeling showed no obvious difference in hair cell numbers in the cochlea between TPRN −/− mice and WT mice under light microscope. However, scanning electronic microscopy revealed progressive degeneration of inner hair cell stereocilia, from apparently normal at postnatal days 3 (P3) to scattered absence at P15 and further to substantial loss at P30. The outer hair cell stereocilia also showed progressive degeneration, though much less severe, Collectively, we conclude that taperin plays an important role in maintenance of hair cell stereocilia. Establishment of TPRN knockout mice enables further investigation into the function of this gene. - Highlights: • TPRN −/− mice were generated using TALEN technique. • TPRN −/− mice presented progressive hearing loss. • WT and TPRN −/− mice showed no difference in hair cell numbers. • TPRN −/− mice showed progressive degeneration of hair cell stereocilia.

  13. Interfacing of differential-capacitive biomimetic hair flow-sensors for optimal sensitivity

    International Nuclear Information System (INIS)

    + Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands))" data-affiliation=" (Transducers Science and Technology Group, MESA+ Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands))" >Dagamseh, A M K; + Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands))" data-affiliation=" (Transducers Science and Technology Group, MESA+ Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands))" >Bruinink, C M; + Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands))" data-affiliation=" (Transducers Science and Technology Group, MESA+ Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands))" >Wiegerink, R J; + Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands))" data-affiliation=" (Transducers Science and Technology Group, MESA+ Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands))" >Lammerink, T S J; + Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands))" data-affiliation=" (Transducers Science and Technology Group, MESA+ Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands))" >Droogendijk, H; + Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands))" data-affiliation=" (Transducers Science and Technology Group, MESA+ Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands))" >Krijnen, G J M

    2013-01-01

    Biologically inspired sensor-designs are investigated as a possible path to surpass the performance of more traditionally engineered designs. Inspired by crickets, artificial hair sensors have shown the ability to detect minute flow signals. This paper addresses developments in the design, fabrication, interfacing and characterization of biomimetic hair flow-sensors towards sensitive high-density arrays. Improvement of the electrode design of the hair sensors has resulted in a reduction of the smallest hair movements that can be measured. In comparison to the arrayed hairs-sensor design, the detection-limit was arguably improved at least twelve-fold, down to 1 mm s –1 airflow amplitude at 250 Hz as measured in a bandwidth of 3 kHz. The directivity pattern closely resembles a figure-of-eight. These sensitive hair-sensors open possibilities for high-resolution spatio-temporal flow pattern observations. (paper)

  14. Frequency response for electromotility of isolated outer hair cells of the guinea pig

    NARCIS (Netherlands)

    Wit, HP; vanDijk, P; Segenhout, HM

    1996-01-01

    Frequency and impulse responses were determined for isolated guinea pig outer hair cells by electrically stimulating the cells between two wire electrodes with white noise. Cells were attached to the bottom of a small culture dish at one end while the other end was freely moving. Results have the

  15. Tauroursodeoxycholic acid attenuates gentamicin-induced cochlear hair cell death in vitro.

    Science.gov (United States)

    Jia, Zhanwei; He, Qiang; Shan, Chunguang; Li, Fengyi

    2018-09-15

    Gentamycin is one of the most clinically used aminoglycoside antibiotics which induce intrinsic apoptosis of hair cells. Tauroursodeoxycholic acid (TUDCA) is known as safe cell-protective agent in disorders associated with apoptosis. We aimed to investigate the protective effects of TUDCA against gentamicin-induced ototoxicity. House Ear Institute-Organ of Corti 1(HEI-OC1) cells and explanted cochlear tissue were treated with gentamicin and TUDCA, followed by serial analyses including cell viability assay, hair cell staining, qPCR, ELISA and western blotting to determine the cell damage by the parameters relevant to cell apoptosis and endoplasmic reticulum stress. TUDCA significantly attenuated gentamicin-induced cell damage in cultured HEI-OC1 cells and explanted cochlear hair cells. TUDCA alleviated gentamicin-induced cell apoptosis, supported by the decreased Bax/Bcl2 ratio compared with that of gentamicin treated alone. TUDCA decreased gentamicin-induced nitric oxide production and protein nitration in both models. In addition, TUDCA suppressed gentamicin-induced endoplasmic reticulum stress as reflected by inversing the expression levels of Binding immunoglobulin protein (Bip), CCAAT/-enhancer-binding protein homologous protein (CHOP) and Caspase 3. TUDCA attenuated gentamicin-induced hair cell death by inhibiting protein nitration activation and ER stress, providing new insights into the new potential therapies for sensorineural deafness. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Hedgehog Signaling Promotes the Proliferation and Subsequent Hair Cell Formation of Progenitor Cells in the Neonatal Mouse Cochlea

    Science.gov (United States)

    Chen, Yan; Lu, Xiaoling; Guo, Luo; Ni, Wenli; Zhang, Yanping; Zhao, Liping; Wu, Lingjie; Sun, Shan; Zhang, Shasha; Tang, Mingliang; Li, Wenyan; Chai, Renjie; Li, Huawei

    2017-01-01

    Hair cell (HC) loss is the major cause of permanent sensorineural hearing loss in mammals. Unlike lower vertebrates, mammalian cochlear HCs cannot regenerate spontaneously after damage, although the vestibular system does maintain limited HC regeneration capacity. Thus HC regeneration from the damaged sensory epithelium has been one of the main areas of research in the field of hearing restoration. Hedgehog signaling plays important roles during the embryonic development of the inner ear, and it is involved in progenitor cell proliferation and differentiation as well as the cell fate decision. In this study, we show that recombinant Sonic Hedgehog (Shh) protein effectively promotes sphere formation, proliferation, and differentiation of Lgr5+ progenitor cells isolated from the neonatal mouse cochlea. To further explore this, we determined the effect of Hedgehog signaling on cell proliferation and HC regeneration in cultured cochlear explant from transgenic R26-SmoM2 mice that constitutively activate Hedgehog signaling in the supporting cells of the cochlea. Without neomycin treatment, up-regulation of Hedgehog signaling did not significantly promote cell proliferation or new HC formation. However, after injury to the sensory epithelium by neomycin treatment, the over-activation of Hedgehog signaling led to significant supporting cell proliferation and HC regeneration in the cochlear epithelium explants. RNA sequencing and real-time PCR were used to compare the transcripts of the cochleae from control mice and R26-SmoM2 mice, and multiple genes involved in the proliferation and differentiation processes were identified. This study has important implications for the treatment of sensorineural hearing loss by manipulating the Hedgehog signaling pathway. PMID:29311816

  17. Hedgehog Signaling Promotes the Proliferation and Subsequent Hair Cell Formation of Progenitor Cells in the Neonatal Mouse Cochlea

    Directory of Open Access Journals (Sweden)

    Yan Chen

    2017-12-01

    Full Text Available Hair cell (HC loss is the major cause of permanent sensorineural hearing loss in mammals. Unlike lower vertebrates, mammalian cochlear HCs cannot regenerate spontaneously after damage, although the vestibular system does maintain limited HC regeneration capacity. Thus HC regeneration from the damaged sensory epithelium has been one of the main areas of research in the field of hearing restoration. Hedgehog signaling plays important roles during the embryonic development of the inner ear, and it is involved in progenitor cell proliferation and differentiation as well as the cell fate decision. In this study, we show that recombinant Sonic Hedgehog (Shh protein effectively promotes sphere formation, proliferation, and differentiation of Lgr5+ progenitor cells isolated from the neonatal mouse cochlea. To further explore this, we determined the effect of Hedgehog signaling on cell proliferation and HC regeneration in cultured cochlear explant from transgenic R26-SmoM2 mice that constitutively activate Hedgehog signaling in the supporting cells of the cochlea. Without neomycin treatment, up-regulation of Hedgehog signaling did not significantly promote cell proliferation or new HC formation. However, after injury to the sensory epithelium by neomycin treatment, the over-activation of Hedgehog signaling led to significant supporting cell proliferation and HC regeneration in the cochlear epithelium explants. RNA sequencing and real-time PCR were used to compare the transcripts of the cochleae from control mice and R26-SmoM2 mice, and multiple genes involved in the proliferation and differentiation processes were identified. This study has important implications for the treatment of sensorineural hearing loss by manipulating the Hedgehog signaling pathway.

  18. HCN channels are not required for mechanotransduction in sensory hair cells of the mouse inner ear.

    Directory of Open Access Journals (Sweden)

    Geoffrey C Horwitz

    Full Text Available The molecular composition of the hair cell transduction channel has not been identified. Here we explore the novel hypothesis that hair cell transduction channels include HCN subunits. The HCN family of ion channels includes four members, HCN1-4. They were originally identified as the molecular correlates of the hyperpolarization-activated, cyclic nucleotide gated ion channels that carry currents known as If, IQ or Ih. However, based on recent evidence it has been suggested that HCN subunits may also be components of the elusive hair cell transduction channel. To investigate this hypothesis we examined expression of mRNA that encodes HCN1-4 in sensory epithelia of the mouse inner ear, immunolocalization of HCN subunits 1, 2 and 4, uptake of the transduction channel permeable dye, FM1-43 and electrophysiological measurement of mechanotransduction current. Dye uptake and transduction current were assayed in cochlear and vestibular hair cells of wildtype mice exposed to HCN channel blockers or a dominant-negative form of HCN2 that contained a pore mutation and in mutant mice that lacked HCN1, HCN2 or both. We found robust expression of HCNs 1, 2 and 4 but little evidence that localized HCN subunits in hair bundles, the site of mechanotransduction. Although high concentrations of the HCN antagonist, ZD7288, blocked 50-70% of the transduction current, we found no reduction of transduction current in either cochlear or vestibular hair cells of HCN1- or HCN2- deficient mice relative to wild-type mice. Furthermore, mice that lacked both HCN1 and HCN2 also had normal transduction currents. Lastly, we found that mice exposed to the dominant-negative mutant form of HCN2 had normal transduction currents as well. Taken together, the evidence suggests that HCN subunits are not required for mechanotransduction in hair cells of the mouse inner ear.

  19. Ca(2+) currents and voltage responses in Type I and Type II hair cells of the chick embryo semicircular canal.

    Science.gov (United States)

    Masetto, Sergio; Zampini, Valeria; Zucca, Giampiero; Valli, Paolo

    2005-11-01

    Type I and Type II hair cells, and Type II hair cells located in different zones of the semicircular canal crista, express different patterns of voltage-dependent K channels, each one specifically shaping the hair cell receptor potential. We report here that, close to hatching, chicken embryo semicircular canal Type I and Type II hair cells express a similar voltage-dependent L-type calcium current (I(Ca)), whose main features are: activation above -60 mV, fast activation kinetics, and scarce inactivation. I(Ca) should be already active at rest in Zone 1 Type II hair cells, whose resting membrane potential was on average slightly less negative than -60 mV. Conversely, I(Ca) would not be active at rest in Type II hair cells from Zone 2 and 3, nor in Type I hair cells, since their resting membrane potential was significantly more negative than -60 mV. However, even small depolarising currents would activate I(Ca) steadily in Zone 2 and 3 Type II hair cells, but not in Type I hair cells because of the robust repolarising action of their specific array of K(+) currents. The implications of the present findings in the afferent discharge are discussed.

  20. Stria vascularis and cochlear hair cell changes in syphilis: A human temporal bone study.

    Science.gov (United States)

    Hızlı, Ömer; Kaya, Serdar; Hızlı, Pelin; Paparella, Michael M; Cureoglu, Sebahattin

    2016-12-01

    To observe any changes in stria vascularis and cochlear hair cells in patients with syphilis. We examined 13 human temporal bone samples from 8 patients with syphilis (our syphilis group), as well as 12 histopathologically normal samples from 9 age-matched patients without syphilis (our control group). We compared, between the two groups, the mean area of the stria vascularis (measured with conventional light microscopy connected to a personal computer) and the mean percentage of cochlear hair cell loss (obtained from cytocochleograms). In our syphilis group, only 1 (7.7%) of the 13 samples had precipitate in the endolymphatic or perilymphatic spaces; 8 (61.5%) of the samples revealed the presence of endolymphatic hydrops (4 cochlear, 4 saccular). The mean area of the stria vascularis did not significantly differ, in any turn of the cochlea, between the 2 groups (P>0.1). However, we did find significant differences between the 2 groups in the mean percentage of outer hair cells in the apical turn (Psyphilis group, we observed either complete loss of the organ of Corti or a flattened organ of Corti without any cells in addition to the absence of both outer and inner hair cells. In this study, syphilis led either to complete loss of the organ of Corti or to significant loss of cochlear hair cells, in addition to cochleosaccular hydrops. But the area of the stria vascularis did not change. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  1. FGF signalling controls the specification of hair placode-derived SOX9 positive progenitors to Merkel cells.

    Science.gov (United States)

    Nguyen, Minh Binh; Cohen, Idan; Kumar, Vinod; Xu, Zijian; Bar, Carmit; Dauber-Decker, Katherine L; Tsai, Pai-Chi; Marangoni, Pauline; Klein, Ophir D; Hsu, Ya-Chieh; Chen, Ting; Mikkola, Marja L; Ezhkova, Elena

    2018-06-13

    Merkel cells are innervated mechanosensory cells responsible for light-touch sensations. In murine dorsal skin, Merkel cells are located in touch domes and found in the epidermis around primary hairs. While it has been shown that Merkel cells are skin epithelial cells, the progenitor cell population that gives rise to these cells is unknown. Here, we show that during embryogenesis, SOX9-positive (+) cells inside hair follicles, which were previously known to give rise to hair follicle stem cells (HFSCs) and cells of the hair follicle lineage, can also give rise to Merkel Cells. Interestingly, while SOX9 is critical for HFSC specification, it is dispensable for Merkel cell formation. Conversely, FGFR2 is required for Merkel cell formation but is dispensable for HFSCs. Together, our studies uncover SOX9(+) cells as precursors of Merkel cells and show the requirement for FGFR2-mediated epithelial signalling in Merkel cell specification.

  2. Mutations in ap1b1 cause mistargeting of the Na(+/K(+-ATPase pump in sensory hair cells.

    Directory of Open Access Journals (Sweden)

    Rachel Clemens Grisham

    Full Text Available The hair cells of the inner ear are polarized epithelial cells with a specialized structure at the apical surface, the mechanosensitive hair bundle. Mechanotransduction occurs within the hair bundle, whereas synaptic transmission takes place at the basolateral membrane. The molecular basis of the development and maintenance of the apical and basal compartments in sensory hair cells is poorly understood. Here we describe auditory/vestibular mutants isolated from forward genetic screens in zebrafish with lesions in the adaptor protein 1 beta subunit 1 (ap1b1 gene. Ap1b1 is a subunit of the adaptor complex AP-1, which has been implicated in the targeting of basolateral membrane proteins. In ap1b1 mutants we observed that although the overall development of the inner ear and lateral-line organ appeared normal, the sensory epithelium showed progressive signs of degeneration. Mechanically-evoked calcium transients were reduced in mutant hair cells, indicating that mechanotransduction was also compromised. To gain insight into the cellular and molecular defects in ap1b1 mutants, we examined the localization of basolateral membrane proteins in hair cells. We observed that the Na(+/K(+-ATPase pump (NKA was less abundant in the basolateral membrane and was mislocalized to apical bundles in ap1b1 mutant hair cells. Accordingly, intracellular Na(+ levels were increased in ap1b1 mutant hair cells. Our results suggest that Ap1b1 is essential for maintaining integrity and ion homeostasis in hair cells.

  3. Causes and Consequences of Sensory Hair Cell Damage and Recovery in Fishes.

    Science.gov (United States)

    Smith, Michael E; Monroe, J David

    2016-01-01

    Sensory hair cells are the mechanotransductive receptors that detect gravity, sound, and vibration in all vertebrates. Damage to these sensitive receptors often results in deficits in vestibular function and hearing. There are currently two main reasons for studying the process of hair cell loss in fishes. First, fishes, like other non-mammalian vertebrates, have the ability to regenerate hair cells that have been damaged or lost via exposure to ototoxic chemicals or acoustic overstimulation. Thus, they are used as a biomedical model to understand the process of hair cell death and regeneration and find therapeutics that treat or prevent human hearing loss. Secondly, scientists and governmental natural resource managers are concerned about the potential effects of intense anthropogenic sounds on aquatic organisms, including fishes. Dr. Arthur N. Popper and his students, postdocs and research associates have performed pioneering experiments in both of these lines of fish hearing research. This review will discuss the current knowledge regarding the causes and consequences of both lateral line and inner ear hair cell damage in teleost fishes.

  4. Position-dependent patterning of spontaneous action potentials in immature cochlear inner hair cells.

    Science.gov (United States)

    Johnson, Stuart L; Eckrich, Tobias; Kuhn, Stephanie; Zampini, Valeria; Franz, Christoph; Ranatunga, Kishani M; Roberts, Terri P; Masetto, Sergio; Knipper, Marlies; Kros, Corné J; Marcotti, Walter

    2011-06-01

    Spontaneous action potential activity is crucial for mammalian sensory system development. In the auditory system, patterned firing activity has been observed in immature spiral ganglion and brain-stem neurons and is likely to depend on cochlear inner hair cell (IHC) action potentials. It remains uncertain whether spiking activity is intrinsic to developing IHCs and whether it shows patterning. We found that action potentials were intrinsically generated by immature IHCs of altricial rodents and that apical IHCs showed bursting activity as opposed to more sustained firing in basal cells. We show that the efferent neurotransmitter acetylcholine fine-tunes the IHC's resting membrane potential (V(m)), and as such is crucial for the bursting pattern in apical cells. Endogenous extracellular ATP also contributes to the V(m) of apical and basal IHCs by triggering small-conductance Ca(2+)-activated K(+) (SK2) channels. We propose that the difference in firing pattern along the cochlea instructs the tonotopic differentiation of IHCs and auditory pathway.

  5. Wnt activation followed by Notch inhibition promotes mitotic hair cell regeneration in the postnatal mouse cochlea

    Science.gov (United States)

    Li, Wenyan; Chen, Yan; Zhang, Shasha; Tang, Mingliang; Sun, Shan; Chai, Renjie; Li, Huawei

    2016-01-01

    Hair cell (HC) loss is the main cause of permanent hearing loss in mammals. Previous studies have reported that in neonatal mice cochleae, Wnt activation promotes supporting cell (SC) proliferation and Notch inhibition promotes the trans-differentiation of SCs into HCs. However, Wnt activation alone fails to regenerate significant amounts of new HCs, Notch inhibition alone regenerates the HCs at the cost of exhausting the SC population, which leads to the death of the newly regenerated HCs. Mitotic HC regeneration might preserve the SC number while regenerating the HCs, which could be a better approach for long-term HC regeneration. We present a two-step gene manipulation, Wnt activation followed by Notch inhibition, to accomplish mitotic regeneration of HCs while partially preserving the SC number. We show that Wnt activation followed by Notch inhibition strongly promotes the mitotic regeneration of new HCs in both normal and neomycin-damaged cochleae while partially preserving the SC number. Lineage tracing shows that the majority of the mitotically regenerated HCs are derived specifically from the Lgr5+ progenitors with or without HC damage. Our findings suggest that the co-regulation of Wnt and Notch signaling might provide a better approach to mitotically regenerate HCs from Lgr5+ progenitor cells. PMID:27564256

  6. Cockayne syndrome group B (Csb) and group a (Csa) deficiencies predispose to hearing loss and cochlear hair cell degeneration in mice.

    Science.gov (United States)

    Nagtegaal, A Paul; Rainey, Robert N; van der Pluijm, Ingrid; Brandt, Renata M C; van der Horst, Gijsbertus T J; Borst, J Gerard G; Segil, Neil

    2015-03-11

    Sensory hair cells in the cochlea, like most neuronal populations that are postmitotic, terminally differentiated, and non-regenerating, depend on robust mechanisms of self-renewal for lifelong survival. We report that hair cell homeostasis requires a specific sub-branch of the DNA damage nucleotide excision repair pathway, termed transcription-coupled repair (TCR). Cockayne syndrome (CS), caused by defects in TCR, is a rare DNA repair disorder with a broad clinical spectrum that includes sensorineural hearing loss. We tested hearing and analyzed the cellular integrity of the organ of Corti in two mouse models of this disease with mutations in the Csb gene (CSB(m/m) mice) and Csa gene (Csa(-/-) mice), respectively. Csb(m/m) and Csa(-/-) mice manifested progressive hearing loss, as measured by an increase in auditory brainstem response thresholds. In contrast to wild-type mice, mutant mice showed reduced or absent otoacoustic emissions, suggesting cochlear outer hair cell impairment. Hearing loss in Csb(m/m) and Csa(-/-) mice correlated with progressive hair cell loss in the base of the organ of Corti, starting between 6 and 13 weeks of age, which increased by 16 weeks of age in a basal-to-apical gradient, with outer hair cells more severely affected than inner hair cells. Our data indicate that the hearing loss observed in CS patients is reproduced in mouse models of this disease. We hypothesize that accumulating DNA damage, secondary to the loss of TCR, contributes to susceptibility to hearing loss. Copyright © 2015 the authors 0270-6474/15/354280-07$15.00/0.

  7. Wnt-10b secreted from lymphocytes promotes differentiation of skin epithelial cells

    International Nuclear Information System (INIS)

    Ouji, Yukiteru; Yoshikawa, Masahide; Shiroi, Akira; Ishizaka, Shigeaki

    2006-01-01

    Wnt-10b was originally isolated from lymphoid tissue and is known to be involved in a wide range of biological actions, while recently it was found to be expressed early in the development of hair follicles. However, few studies have been conducted concerning the role of Wnt-10b with the differentiation of skin epithelial cells. To evaluate its role in epithelial differentiation, we purified Wnt-10b from the supernatant of a concanavalin A-stimulated lymphocyte culture using an affinity column and investigated its effects on the differentiation of adult mouse-derived primary skin epithelial cells (MPSEC). MPSEC cultured with Wnt-10b showed morphological changes from cuboidal to spindle-shaped with inhibited proliferation, and also obtained characteristics of the hair shaft and inner root sheath of the hair follicle, represented by red-colored Ayoub Shklar staining, and reactions to AE-13 and AE-15 as seen with immunocytology. Further, RT-PCR analysis demonstrated the expression of mRNA for keratin 1, keratin 2, loricrin, mHa5, and mHb5, in association with a decreased expression of the basal cell marker keratin 5, in Wnt-10b-treated MPSEC. In addition, involvement of the canonical Wnt signal pathway was demonstrated by a TCF reporter (pTOPFLASH) assay. These results suggest that Wnt-10b promotes the differentiation of MPSEC and may play an important role in hair follicle development by promoting differentiation of epithelial cells

  8. Up-to-date Clinical Trials of Hair Regeneration Using Conditioned Media of Adipose-Derived Stem Cells in Male and Female Pattern Hair Loss.

    Science.gov (United States)

    Shin, Hyoseung; Won, Chong Hyun; Chung, Woon-Kyung; Park, Byung-Soon

    2017-01-01

    The primary roles of mesenchymal stem cells (MSCs) are to maintain the stem cell niche, facilitate recovery after injury, and ensure healthy aging and the homeostasis of organ and tissues. MSCs have recently emerged as a new therapeutic option for hair loss. Since adipose-derived stem cells (ADSCs) are the most accessible sources of MSCs, ADSCbased hair regeneration is investigated. Besides replacing degenerated cells in affected organs, ADSCs exhibit their beneficial effects through the paracrine actions of various cytokines and growth factors. Several laboratory experiments and animal studies have shown that ADSC-related proteins can stimulate hair growth. In addition, we introduce our clinical pilot studies using conditioned media of ADSCs for pattern hair loss in men and women. We believe that conditioned media of ADSCs represents a promising alternative therapeutic strategy for hair loss. We also discuss practical therapeutic challenges and the direction of future research. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  9. Intercellular K⁺ accumulation depolarizes Type I vestibular hair cells and their associated afferent nerve calyx.

    Science.gov (United States)

    Contini, D; Zampini, V; Tavazzani, E; Magistretti, J; Russo, G; Prigioni, I; Masetto, S

    2012-12-27

    Mammalian vestibular organs contain two types of sensory receptors, named Type I and Type II hair cells. While Type II hair cells are contacted by several small afferent nerve terminals, the basolateral surface of Type I hair cells is almost entirely enveloped by a single large afferent nerve terminal, called calyx. Moreover Type I, but not Type II hair cells, express a low-voltage-activated outward K(+) current, I(K,L), which is responsible for their much lower input resistance (Rm) at rest as compared to Type II hair cells. The functional meaning of I(K,L) and associated calyx is still enigmatic. By combining the patch-clamp whole-cell technique with the mouse whole crista preparation, we have recorded the current- and voltage responses of in situ hair cells. Outward K(+) current activation resulted in K(+) accumulation around Type I hair cells, since it induced a rightward shift of the K(+) reversal potential the magnitude of which depended on the amplitude and duration of K(+) current flow. Since this phenomenon was never observed for Type II hair cells, we ascribed it to the presence of a residual calyx limiting K(+) efflux from the synaptic cleft. Intercellular K(+) accumulation added a slow (τ>100ms) depolarizing component to the cell voltage response. In a few cases we were able to record from the calyx and found evidence for intercellular K(+) accumulation as well. The resulting depolarization could trigger a discharge of action potentials in the afferent nerve fiber. Present results support a model where pre- and postsynaptic depolarization produced by intercellular K(+) accumulation cooperates with neurotransmitter exocytosis in sustaining afferent transmission arising from Type I hair cells. While vesicular transmission together with the low Rm of Type I hair cells appears best suited for signaling fast head movements, depolarization produced by intercellular K(+) accumulation could enhance signal transmission during slow head movements. Copyright

  10. Auditory hair cell defects as potential cause for sensorineural deafness in Wolf-Hirschhorn syndrome.

    Science.gov (United States)

    Ahmed, Mohi; Ura, Kiyoe; Streit, Andrea

    2015-09-01

    WHSC1 is a histone methyltransferase (HMT) that catalyses the addition of methyl groups to lysine 36 on histone 3. In humans, WHSC1 haploinsufficiency is associated with all known cases of Wolf-Hirschhorn syndrome (WHS). The cardinal feature of WHS is a craniofacial dysmorphism, which is accompanied by sensorineural hearing loss in 15% of individuals with WHS. Here, we show that WHSC1-deficient mice display craniofacial defects that overlap with WHS, including cochlea anomalies. Although auditory hair cells are specified normally, their stereocilia hair bundles required for sound perception fail to develop the appropriate morphology. Furthermore, the orientation and cellular organisation of cochlear hair cells and their innervation are defective. These findings identify, for the first time, the likely cause of sensorineural hearing loss in individuals with WHS. © 2015. Published by The Company of Biologists Ltd.

  11. Auditory hair cell defects as potential cause for sensorineural deafness in Wolf-Hirschhorn syndrome

    Directory of Open Access Journals (Sweden)

    Mohi Ahmed

    2015-09-01

    Full Text Available WHSC1 is a histone methyltransferase (HMT that catalyses the addition of methyl groups to lysine 36 on histone 3. In humans, WHSC1 haploinsufficiency is associated with all known cases of Wolf-Hirschhorn syndrome (WHS. The cardinal feature of WHS is a craniofacial dysmorphism, which is accompanied by sensorineural hearing loss in 15% of individuals with WHS. Here, we show that WHSC1-deficient mice display craniofacial defects that overlap with WHS, including cochlea anomalies. Although auditory hair cells are specified normally, their stereocilia hair bundles required for sound perception fail to develop the appropriate morphology. Furthermore, the orientation and cellular organisation of cochlear hair cells and their innervation are defective. These findings identify, for the first time, the likely cause of sensorineural hearing loss in individuals with WHS.

  12. ER stress inhibitor attenuates hearing loss and hair cell death in Cdh23erl/erl mutant mice.

    Science.gov (United States)

    Hu, Juan; Li, Bo; Apisa, Luke; Yu, Heping; Entenman, Shami; Xu, Min; Stepanyan, Ruben; Guan, Bo-Jhih; Müller, Ulrich; Hatzoglou, Maria; Zheng, Qing Yin

    2016-11-24

    Hearing loss is one of the most common sensory impairments in humans. Mouse mutant models helped us to better understand the mechanisms of hearing loss. Recently, we have discovered that the erlong (erl) mutation of the cadherin23 (Cdh23) gene leads to hearing loss due to hair cell apoptosis. In this study, we aimed to reveal the molecular pathways upstream to apoptosis in hair cells to exploit more effective therapeutics than an anti-apoptosis strategy. Our results suggest that endoplasmic reticulum (ER) stress is the earliest molecular event leading to the apoptosis of hair cells and hearing loss in erl mice. We also report that the ER stress inhibitor, Salubrinal (Sal), could delay the progression of hearing loss and preserve hair cells. Our results provide evidence that therapies targeting signaling pathways in ER stress development prevent hair cell apoptosis at an early stage and lead to better outcomes than those targeting downstream factors, such as tip-link degeneration and apoptosis.

  13. The Rho GTPase Cdc42 regulates hair cell planar polarity and cellular patterning in the developing cochlea

    Directory of Open Access Journals (Sweden)

    Anna Kirjavainen

    2015-03-01

    Full Text Available Hair cells of the organ of Corti (OC of the cochlea exhibit distinct planar polarity, both at the tissue and cellular level. Planar polarity at tissue level is manifested as uniform orientation of the hair cell stereociliary bundles. Hair cell intrinsic polarity is defined as structural hair bundle asymmetry; positioning of the kinocilium/basal body complex at the vertex of the V-shaped bundle. Consistent with strong apical polarity, the hair cell apex displays prominent actin and microtubule cytoskeletons. The Rho GTPase Cdc42 regulates cytoskeletal dynamics and polarization of various cell types, and, thus, serves as a candidate regulator of hair cell polarity. We have here induced Cdc42 inactivation in the late-embryonic OC. We show the role of Cdc42 in the establishment of planar polarity of hair cells and in cellular patterning. Abnormal planar polarity was displayed as disturbances in hair bundle orientation and morphology and in kinocilium/basal body positioning. These defects were accompanied by a disorganized cell-surface microtubule network. Atypical protein kinase C (aPKC, a putative Cdc42 effector, colocalized with Cdc42 at the hair cell apex, and aPKC expression was altered upon Cdc42 depletion. Our data suggest that Cdc42 together with aPKC is part of the machinery establishing hair cell planar polarity and that Cdc42 acts on polarity through the cell-surface microtubule network. The data also suggest that defects in apical polarization are influenced by disturbed cellular patterning in the OC. In addition, our data demonstrates that Cdc42 is required for stereociliogenesis in the immature cochlea.

  14. Micronucleus frequency in exfoliated buccal cells from hairdresser who expose to hair products

    Directory of Open Access Journals (Sweden)

    Koh Hui Yee

    2015-06-01

    Full Text Available Background: Hairdresser is one of the fastest growing occupations in today’s society. Hairdresser help styling, cutting, colouring, perming, curling, straightening hair and various treatment to customer. Somehow, hairdresser are constantly exposed to chemical substances such as aromatic amines, hydrogen peroxide, thioglycolic acid, formaldehyde in hair products which can cause damage to human’s genome. Micronucleus is one of the effective biomarker for processes associated with the induction of DNA damage. Purpose: The aim of this study was to determine the micronucleus frequencies in buccal mucosa epithelial cells of hairdresser who were exposed to chemical of hair products. Method: This study was conducted on twenty female subjects, who were divided into 2 groups: exposed and non-exposed (control group. All subjects recruited were working in the same beauty salon. Buccal cells were obtained from each individual by using cytobrush. The cells were stained with modified Feulgen-Ronssenback method and counting of micronucleus per 1000 cell was done under light microscope. The data were analyzed using independent t-test and one-way Anova (p<0.05. Result: The result showed a significant difference in micronucleus frequency between 2 groups. There were a significantly increase of micronucleus frequency in hairdressers and increase of  micronucleus frequency with the longer duration of exposure. Conclusion: It concluded that the chemical substances of hair products had affected the micronucleus frequency ofthe epithelial cells in buccal mucosa of hairdressers.

  15. Noise-Induced Loss of Hair Cells and Cochlear Synaptopathy Are Mediated by the Activation of AMPK

    Science.gov (United States)

    Hill, Kayla; Yuan, Hu; Wang, Xianren

    2016-01-01

    Noise-induced hearing loss (NIHL) is a major unresolved public health problem. Here, we investigate pathomechanisms of sensory hair cell death and suggest a novel target for protective intervention. Cellular survival depends upon maintenance of energy homeostasis, largely by AMP-activated protein kinase (AMPK). In response to a noise exposure in CBA/J mice, the levels of phosphorylated AMPKα increased in hair cells in a noise intensity-dependent manner. Inhibition of AMPK via siRNA or the pharmacological inhibitor compound C attenuated noise-induced loss of outer hair cells (OHCs) and synaptic ribbons, and preserved auditory function. Additionally, noise exposure increased the activity of the upstream AMPK kinase liver kinase B1 (LKB1) in cochlear tissues. The inhibition of LKB1 by siRNA attenuated the noise-increased phosphorylation of AMPKα in OHCs, reduced the loss of inner hair cell synaptic ribbons and OHCs, and protected against NIHL. These results indicate that noise exposure induces hair cell death and synaptopathy by activating AMPK via LKB1-mediated pathways. Targeting these pathways may provide a novel route to prevent NIHL. SIGNIFICANCE STATEMENT Our results demonstrate for the first time that the activation of AMP-activated protein kinase (AMPK) α in sensory hair cells is noise intensity dependent and contributes to noise-induced hearing loss by mediating the loss of inner hair cell synaptic ribbons and outer hair cells. Noise induces the phosphorylation of AMPKα1 by liver kinase B1 (LKB1), triggered by changes in intracellular ATP levels. The inhibition of AMPK activation by silencing AMPK or LKB1, or with the pharmacological inhibitor compound C, reduced outer hair cell and synaptic ribbon loss as well as noise-induced hearing loss. This study provides new insights into mechanisms of noise-induced hearing loss and suggests novel interventions for the prevention of the loss of sensory hair cells and cochlear synaptopathy. PMID:27413159

  16. Hair regrowth in alopecia areata patients following Stem Cell Educator therapy.

    Science.gov (United States)

    Li, Yanjia; Yan, Baoyong; Wang, Hepeng; Li, Heng; Li, Quanhai; Zhao, Dong; Chen, Yana; Zhang, Ye; Li, Wenxia; Zhang, Jun; Wang, Shanfeng; Shen, Jie; Li, Yunxiang; Guindi, Edward; Zhao, Yong

    2015-04-20

    Alopecia areata (AA) is one of the most common autoimmune diseases and targets the hair follicles, with high impact on the quality of life and self-esteem of patients due to hair loss. Clinical management and outcomes are challenged by current limited immunosuppressive and immunomodulating regimens. We have developed a Stem Cell Educator therapy in which a patient's blood is circulated through a closed-loop system that separates mononuclear cells from the whole blood, allows the cells to briefly interact with adherent human cord blood-derived multipotent stem cells (CB-SC), and returns the "educated" autologous cells to the patient's circulation. In an open-label, phase 1/phase 2 study, patients (N = 9) with severe AA received one treatment with the Stem Cell Educator therapy. The median age was 20 years (median alopecic duration, 5 years). Clinical data demonstrated that patients with severe AA achieved improved hair regrowth and quality of life after receiving Stem Cell Educator therapy. Flow cytometry revealed the up-regulation of Th2 cytokines and restoration of balancing Th1/Th2/Th3 cytokine production in the peripheral blood of AA subjects. Immunohistochemistry indicated the formation of a "ring of transforming growth factor beta 1 (TGF-β1)" around the hair follicles, leading to the restoration of immune privilege of hair follicles and the protection of newly generated hair follicles against autoimmune destruction. Mechanistic studies revealed that co-culture with CB-SC may up-regulate the expression of coinhibitory molecules B and T lymphocyte attenuator (BTLA) and programmed death-1 receptor (PD-1) on CD8β(+)NKG2D(+) effector T cells and suppress their proliferation via herpesvirus entry mediator (HVEM) ligands and programmed death-1 ligand (PD-L1) on CB-SCs. Current clinical data demonstrated the safety and efficacy of the Stem Cell Educator therapy for the treatment of AA. This innovative approach produced lasting improvement in hair regrowth in

  17. Definitive Endoderm Formation from Plucked Human Hair-Derived Induced Pluripotent Stem Cells and SK Channel Regulation

    Directory of Open Access Journals (Sweden)

    Anett Illing

    2013-01-01

    Full Text Available Pluripotent stem cells present an extraordinary powerful tool to investigate embryonic development in humans. Essentially, they provide a unique platform for dissecting the distinct mechanisms underlying pluripotency and subsequent lineage commitment. Modest information currently exists about the expression and the role of ion channels during human embryogenesis, organ development, and cell fate determination. Of note, small and intermediate conductance, calcium-activated potassium channels have been reported to modify stem cell behaviour and differentiation. These channels are broadly expressed throughout human tissues and are involved in various cellular processes, such as the after-hyperpolarization in excitable cells, and also in differentiation processes. To this end, human induced pluripotent stem cells (hiPSCs generated from plucked human hair keratinocytes have been exploited in vitro to recapitulate endoderm formation and, concomitantly, used to map the expression of the SK channel (SKCa subtypes over time. Thus, we report the successful generation of definitive endoderm from hiPSCs of ectodermal origin using a highly reproducible and robust differentiation system. Furthermore, we provide the first evidence that SKCas subtypes are dynamically regulated in the transition from a pluripotent stem cell to a more lineage restricted, endodermal progeny.

  18. ROOT HAIR DEFECTIVE SIX-LIKE Class I Genes Promote Root Hair Development in the Grass Brachypodium distachyon.

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    Chul Min Kim

    2016-08-01

    Full Text Available Genes encoding ROOT HAIR DEFECTIVE SIX-LIKE (RSL class I basic helix loop helix proteins are expressed in future root hair cells of the Arabidopsis thaliana root meristem where they positively regulate root hair cell development. Here we show that there are three RSL class I protein coding genes in the Brachypodium distachyon genome, BdRSL1, BdRSL2 and BdRSL3, and each is expressed in developing root hair cells after the asymmetric cell division that forms root hair cells and hairless epidermal cells. Expression of BdRSL class I genes is sufficient for root hair cell development: ectopic overexpression of any of the three RSL class I genes induces the development of root hairs in every cell of the root epidermis. Expression of BdRSL class I genes in root hairless Arabidopsis thaliana root hair defective 6 (Atrhd6 Atrsl1 double mutants, devoid of RSL class I function, restores root hair development indicating that the function of these proteins has been conserved. However, neither AtRSL nor BdRSL class I genes is sufficient for root hair development in A. thaliana. These data demonstrate that the spatial pattern of class I RSL activity can account for the pattern of root hair cell differentiation in B. distachyon. However, the spatial pattern of class I RSL activity cannot account for the spatial pattern of root hair cells in A. thaliana. Taken together these data indicate that that the functions of RSL class I proteins have been conserved among most angiosperms-monocots and eudicots-despite the dramatically different patterns of root hair cell development.

  19. Role for a Novel Usher Protein Complex in Hair Cell Synaptic Maturation

    Science.gov (United States)

    Zallocchi, Marisa; Meehan, Daniel T.; Delimont, Duane; Rutledge, Joseph; Gratton, Michael Anne; Flannery, John; Cosgrove, Dominic

    2012-01-01

    The molecular mechanisms underlying hair cell synaptic maturation are not well understood. Cadherin-23 (CDH23), protocadherin-15 (PCDH15) and the very large G-protein coupled receptor 1 (VLGR1) have been implicated in the development of cochlear hair cell stereocilia, while clarin-1 has been suggested to also play a role in synaptogenesis. Mutations in CDH23, PCDH15, VLGR1 and clarin-1 cause Usher syndrome, characterized by congenital deafness, vestibular dysfunction and retinitis pigmentosa. Here we show developmental expression of these Usher proteins in afferent spiral ganglion neurons and hair cell synapses. We identify a novel synaptic Usher complex comprised of clarin-1 and specific isoforms of CDH23, PCDH15 and VLGR1. To establish the in vivo relevance of this complex, we performed morphological and quantitative analysis of the neuronal fibers and their synapses in the Clrn1−/− mouse, which was generated by incomplete deletion of the gene. These mice showed a delay in neuronal/synaptic maturation by both immunostaining and electron microscopy. Analysis of the ribbon synapses in Ames waltzerav3J mice also suggests a delay in hair cell synaptogenesis. Collectively, these results show that, in addition to the well documented role for Usher proteins in stereocilia development, Usher protein complexes comprised of specific protein isoforms likely function in synaptic maturation as well. PMID:22363448

  20. Role for a novel Usher protein complex in hair cell synaptic maturation.

    Directory of Open Access Journals (Sweden)

    Marisa Zallocchi

    Full Text Available The molecular mechanisms underlying hair cell synaptic maturation are not well understood. Cadherin-23 (CDH23, protocadherin-15 (PCDH15 and the very large G-protein coupled receptor 1 (VLGR1 have been implicated in the development of cochlear hair cell stereocilia, while clarin-1 has been suggested to also play a role in synaptogenesis. Mutations in CDH23, PCDH15, VLGR1 and clarin-1 cause Usher syndrome, characterized by congenital deafness, vestibular dysfunction and retinitis pigmentosa. Here we show developmental expression of these Usher proteins in afferent spiral ganglion neurons and hair cell synapses. We identify a novel synaptic Usher complex comprised of clarin-1 and specific isoforms of CDH23, PCDH15 and VLGR1. To establish the in vivo relevance of this complex, we performed morphological and quantitative analysis of the neuronal fibers and their synapses in the Clrn1-/- mouse, which was generated by incomplete deletion of the gene. These mice showed a delay in neuronal/synaptic maturation by both immunostaining and electron microscopy. Analysis of the ribbon synapses in Ames waltzer(av3J mice also suggests a delay in hair cell synaptogenesis. Collectively, these results show that, in addition to the well documented role for Usher proteins in stereocilia development, Usher protein complexes comprised of specific protein isoforms likely function in synaptic maturation as well.

  1. Organ-level quorum sensing directs regeneration in hair stem cell populations

    Science.gov (United States)

    Chen, Chih-Chiang; Wang, Lei; Plikus, Maksim V.; Jiang, Ting Xin; Murray, Philip J.; Ramos, Raul; Guerrero-Juarez, Christian F.; Hughes, Michael W; Lee, Oscar K.; Shi, Songtao; Widelitz, Randall B.; Lander, Arthur D.; Chuong, Cheng Ming

    2015-01-01

    SUMMARY Coordinated organ behavior is crucial for an effective response to environmental stimuli. By studying regeneration of hair follicles in response to patterned hair removal, we demonstrate that organ-level quorum sensing allows coordinated responses to skin injury. Removing hair at different densities leads to a regeneration of up to 5 times more neighboring, unplucked resting hairs, indicating activation of a collective decision-making process. Through data modeling, the range of the quorum signal was estimated to be on the order of 1 mm, greater than expected for a diffusible molecular cue. Molecular and genetic analysis uncovered a two-step mechanism, where release of CCL2 from injured hairs leads to recruitment of TNF-α secreting macrophages, which accumulate and signal to both plucked and unplucked follicles. By coupling immune response with regeneration, this mechanism allows skin to respond predictively to distress, disregarding mild injury, while meeting stronger injury with full-scale cooperative activation of stem cells. PMID:25860610

  2. Hair cosmetics and camouflage technics

    Directory of Open Access Journals (Sweden)

    Zahide Eriş Eken

    2014-06-01

    Full Text Available Hair is composed of a mixture of trace elements in small quantities, proteins, lipids and water. Proteins consist of helical polypeptide amino acid molecules. In the hair cells; polypeptide chains of keratin protein would be organized in filaments. In recent years, hair cosmetics showed a significant change and development. The content of shampoos which is used to cleanse the hair has enhanced significantly. Hair conditioner, hair styling products, pomades, brilliantine, and gloss sprays, hair protective products, camouflage products are most commonly used hair cosmetics. Hair shaping procedures are frequently applied.

  3. Three-dimensional architecture of hair-cell linkages as revealedby electron-microscopic tomography

    Energy Technology Data Exchange (ETDEWEB)

    Auer, Manfred; Koster, Bram; Ziese, Ulrike; Bajaj, Chandrajit; Volkmann, Niels; Wang, Da Neng; Hudspeth, A. James

    2006-07-28

    The senses of hearing and balance rest upon mechanoelectrical transduction by the hair bundles of hair cells in the inner ear. Located at the apical cellular surface, each hair bundle comprises several tens of stereocilia and a single kinocilium that are interconnected by extracellular proteinaceous links. Using electron-microscopic tomography of bullfrog saccular sensory epithelia, we examined the three-dimensional structures of ankle or basal links, kinociliary links, and tip links. We observed clear differences in the dimensions and appearances of the three links. We found two distinct populations of tip links suggestive of the involvement of two proteins or splice variants. We noted auxiliary links connecting the upper portions of tip links to the taller stereocilia. Tip links and auxiliary links show a tendency to adopt a globular conformation when disconnected from the membrane surface.

  4. Trace element distribution in the hair of some sickle cell anemia patients and controls

    International Nuclear Information System (INIS)

    Oluwole, A.F.; Asubiojo, O.I.; Adekile, A.D.; Filby, R.H.; Bragg, A.; Grimm, C.I.

    1990-01-01

    Hair samples of some young sickle cell anemia (SCA) and Control patients in Nigeria were analyzed for 12 elements, viz, Se, Hg, Cr, Fe, Zn, Co, Cu, Br, As, Sb, Na, and Sc, using instrumental Neutron Activation Analysis (INAA). With the exception of Cu, which was found to be significantly higher in the hair of SCA patients (at the 0.05 level of the t-test), there were generally no significant differences in elemental concentrations within the two groups. A preliminary study of the elemental contents of the fingernails of the same subjects showed a higher abundance of most of the elements in nail than in hair. These preliminary results were compared with similar studies form some other parts of the world

  5. Human Wharton's Jelly Mesenchymal Stem Cells plasticity augments scar-free skin wound healing with hair growth.

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    Vikram Sabapathy

    Full Text Available Human mesenchymal stem cells (MSCs are a promising candidate for cell-based transplantation and regenerative medicine therapies. Thus in the present study Wharton's Jelly Mesenchymal Stem Cells (WJ-MSCs have been derived from extra embryonic umbilical cord matrix following removal of both arteries and vein. Also, to overcome the clinical limitations posed by fetal bovine serum (FBS supplementation because of xenogeneic origin of FBS, usual FBS cell culture supplement has been replaced with human platelet lysate (HPL. Apart from general characteristic features of bone marrow-derived MSCs, wharton jelly-derived MSCs have the ability to maintain phenotypic attributes, cell growth kinetics, cell cycle pattern, in vitro multilineage differentiation plasticity, apoptotic pattern, normal karyotype-like intrinsic mesenchymal stem cell properties in long-term in vitro cultures. Moreover, the WJ-MSCs exhibited the in vitro multilineage differentiation capacity by giving rise to differentiated cells of not only mesodermal lineage but also to the cells of ectodermal and endodermal lineage. Also, WJ-MSC did not present any aberrant cell state upon in vivo transplantation in SCID mice and in vitro soft agar assays. The immunomodulatory potential assessed by gene expression levels of immunomodulatory factors upon exposure to inflammatory cytokines in the fetal WJ-MSCs was relatively higher compared to adult bone marrow-derived MSCs. WJ-MSCs seeded on decellularized amniotic membrane scaffold transplantation on the skin injury of SCID mice model demonstrates that combination of WJ-MSCs and decellularized amniotic membrane scaffold exhibited significantly better wound-healing capabilities, having reduced scar formation with hair growth and improved biomechanical properties of regenerated skin compared to WJ-MSCs alone. Further, our experimental data indicate that indocyanin green (ICG at optimal concentration can be resourcefully used for labeling of stem cells

  6. Isolation of hair follicle bulge stem cells from YFP-expressing reporter mice.

    Science.gov (United States)

    Nakrieko, Kerry-Ann; Irvine, Timothy S; Dagnino, Lina

    2013-01-01

    In this article we provide a method to isolate hair follicle stem cells that have undergone targeted gene inactivation. The mice from which these cells are isolated are bred into a Rosa26-yellow fluorescent protein (YFP) reporter background, which results in YFP expression in the targeted stem cell population. These cells are isolated and purified by fluorescence-activated cell sorting, using epidermal stem cell-specific markers in conjunction with YFP fluorescence. The purified cells can be used for gene expression studies, clonogenic experiments, and biological assays, such as viability and capacity for directional migration.

  7. Ingrown Hair

    Science.gov (United States)

    Ingrown hair Overview An ingrown hair occurs when a shaved or tweezed hair grows back into the skin. It can cause inflammation, pain and tiny bumps in the area where the hair was removed. Ingrown hair is a common condition ...

  8. Body Hair

    Science.gov (United States)

    ... girlshealth.gov/ Home Body Puberty Body hair Body hair Even before you get your first period , you ... removing pubic hair Ways to get rid of hair top Removing body hair can cause skin irritation, ...

  9. Evolution of vertebrate mechanosensory hair cells and inner ears: toward identifying stimuli that select mutation driven altered morphologies

    Science.gov (United States)

    Fritzsch, Bernd; Straka, Hans

    2014-01-01

    Among the major distance senses of vertebrates, the ear is unique in its complex morphological changes during evolution. Conceivably, these changes enable the ear to adapt toward sensing various physically well-characterized stimuli. This review develops a scenario that integrates sensory cell with organ evolution. We propose that molecular and cellular evolution of the vertebrate hair cells occurred prior to the formation of the vertebrate ear. We previously proposed that the genes driving hair cell differentiation, were aggregated in the otic region through developmental re-patterning that generated a unique vertebrate embryonic structure, the otic placode. In agreement with the presence of graviceptive receptors in many vertebrate outgroups, it is likely that the vertebrate ear originally functioned as a simple gravity-sensing organ. Based on the rare occurrence of angular acceleration receptors in vertebrate outgroups, we further propose that the canal system evolved with a more sophisticated ear morphogenesis. This evolving morphogenesis obviously turned the initial otocyst into a complex set of canals and recesses, harboring multiple sensory epithelia each adapted to the acquisition of a specific aspect of a given physical stimulus. As support for this evolutionary progression, we provide several details of the molecular basis of ear development. PMID:24281353

  10. Minocycline attenuates streptomycin-induced cochlear hair cell death by inhibiting protein nitration and poly (ADP-ribose) polymerase activation.

    Science.gov (United States)

    Wang, Ping; Li, Haonan; Yu, Shuyuan; Jin, Peng; Hassan, Abdurahman; Du, Bo

    2017-08-24

    This study aimed to elucidate the protective effect of minocycline against streptomycin-induced damage of cochlear hair cells and its mechanism. Cochlear membranes were isolated from newborn Wistar rats and randomly divided into control, 500μmol/L streptomycin, 100μmol/L minocycline, and streptomycin and minocycline treatment groups. Hair cell survival was analyzed by detecting the expression of 3-nitrotyrosine (3-NT) in cochlear hair cells by immunofluorescence and an enzyme-linked immunosorbent assay. Expression of 3-NT and inducible nitric oxide synthase (iNOS), and poly (ADP-Ribose) polymerase (PARP) and caspase-3 activation were evaluated by western blotting. The results demonstrated hair cell loss at 24h after streptomycin treatment. No change was found in supporting cells of the cochleae. Minocycline pretreatment improved hair cell survival and significantly reduced the expression of iNOS and 3-NT in cochlear tissues compared with the streptomycin treatment group. PARP and caspase-3 activation was increased in the streptomycin treatment group compared with the control group, and pretreatment with minocycline decreased cleaved PARP and activated caspase-3 expression. Minocycline protected cochlear hair cells from injury caused by streptomycin in vitro. The mechanism underlying the protective effect may be associated with the inhibition of excessive formation of nitric oxide, reduction of the nitration stress reaction, and inhibition of PARP and caspase-3 activation in cochlear hair cells. Combined minocycline therapy can be applied to patients requiring streptomycin treatment. Copyright © 2017. Published by Elsevier B.V.

  11. Wnt1a maintains characteristics of dermal papilla cells that induce mouse hair regeneration in a 3D preculture system.

    Science.gov (United States)

    Dong, Liang; Hao, Haojie; Liu, Jiejie; Tong, Chuan; Ti, Dongdong; Chen, Deyun; Chen, Li; Li, Meirong; Liu, Huiling; Fu, Xiaobing; Han, Weidong

    2017-05-01

    Hair follicle morphogenesis and regeneration depend on intensive but well-orchestrated interactions between epithelial and mesenchymal components. Therefore, an alternative strategy to reproduce the process of epithelial-mesenchymal interaction in vitro could use a 3D system containing appropriate cell populations. The 3D air-liquid culture system for reproducibly generating hair follicles from dissociated epithelial and dermal papilla (DP) cells combined with a collagen-chitosan scaffold is described in this study. Wnt-CM was prepared from the supernatant of Wnt1a-expressing bone marrow mesenchymal stem cells (BM-MSCs) that maintain the hair-inducing gene expression of DP cells. The collagen-chitosan scaffold cells (CCS cells) were constructed using a two-step method by inoculating the Wnt-CM-treated DP cells and epidermal (EP) cells into the CCS. The cells in the air-liquid culture formed dermal condensates and a proliferative cell layer in vitro. The CCS cells were able to induce hair regeneration in nude mice. The results demonstrate that Wnt-CM can maintain the hair induction ability of DP cells in expansion cultures, and this approach can be used for large-scale preparation of CCS cells in vitro to treat hair loss. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Wnt-10b promotes differentiation of skin epithelial cells in vitro

    International Nuclear Information System (INIS)

    Ouji, Yukiteru; Yoshikawa, Masahide; Shiroi, Akira; Ishizaka, Shigeaki

    2006-01-01

    To evaluate the role of Wnt-10b in epithelial differentiation, we investigated the effects of Wnt-10b on adult mouse-derived primary skin epithelial cells (MPSEC). Recombinant Wnt-10b protein (rWnt-10b) was prepared using a gene engineering technique and MPSEC were cultured in its presence, which resulted in morphological changes from cuboidal to spindle-shaped and inhibited their proliferation. Further, involvement of the canonical Wnt signal pathway was also observed. MPSEC treated with rWnt-10b showed characteristics of the hair shaft and inner root sheath of the hair follicle, in results of Ayoub Shklar staining and immunocytochemistry. Further, the cells expressed mRNA for differentiated epithelial cells, including keratin 1, keratin 2, loricrin, mHa5, and mHb5, in association with a decreased expression of the basal cell marker keratin 5. These results suggest that Wnt-10b promotes the differentiation of MPSEC

  13. The actin-binding proteins eps8 and gelsolin have complementary roles in regulating the growth and stability of mechanosensory hair bundles of mammalian cochlear outer hair cells.

    Directory of Open Access Journals (Sweden)

    Jennifer Olt

    Full Text Available Sound transduction depends upon mechanosensitive channels localized on the hair-like bundles that project from the apical surface of cochlear hair cells. Hair bundles show a stair-case structure composed of rows of stereocilia, and each stereocilium contains a core of tightly-packed and uniformly-polarized actin filaments. The growth and maintenance of the stereociliary actin core are dynamically regulated. Recently, it was shown that the actin-binding protein gelsolin is expressed in the stereocilia of outer hair cells (OHCs and in its absence they become long and straggly. Gelsolin is part of a whirlin scaffolding protein complex at the stereocilia tip, which has been shown to interact with other actin regulatory molecules such as Eps8. Here we investigated the physiological effects associated with the absence of gelsolin and its possible overlapping role with Eps8. We found that, in contrast to Eps8, gelsolin does not affect mechanoelectrical transduction during immature stages of development. Moreover, OHCs from gelsolin knockout mice were able to mature into fully functional sensory receptors as judged by the normal resting membrane potential and basolateral membrane currents. Mechanoelectrical transducer current in gelsolin-Eps8 double knockout mice showed a profile similar to that observed in the single mutants for Eps8. We propose that gelsolin has a non-overlapping role with Eps8. While Eps8 is mainly involved in the initial growth of stereocilia in both inner hair cells (IHCs and OHCs, gelsolin is required for the maintenance of mature hair bundles of low-frequency OHCs after the onset of hearing.

  14. Mitochondria in aging cell differentiation

    Czech Academy of Sciences Publication Activity Database

    Palková, Zdena; Váchová, Libuše

    2016-01-01

    Roč. 8, č. 7 (2016), s. 1287-1288 ISSN 1945-4589 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 Keywords : mitochondria * cell differentiation * retrograde signaling Subject RIV: EE - Microbiology, Virology Impact factor: 4.867, year: 2016

  15. Hair curvature: a natural dialectic and review.

    Science.gov (United States)

    Nissimov, Joseph N; Das Chaudhuri, Asit Baran

    2014-08-01

    Although hair forms (straight, curly, wavy, etc.) are present in apparently infinite variations, each fibre can be reduced to a finite sequence of tandem segments of just three types: straight, bent/curly, or twisted. Hair forms can thus be regarded as resulting from genetic pathways that induce, reverse or modulate these basic curvature modes. However, physical interconversions between twists and curls demonstrate that strict one-to-one correspondences between them and their genetic causes do not exist. Current hair-curvature theories do not distinguish between bending and twisting mechanisms. We here introduce a multiple papillary centres (MPC) model which is particularly suitable to explain twisting. The model combines previously known features of hair cross-sectional morphology with partially/completely separated dermal papillae within single follicles, and requires such papillae to induce differential growth rates of hair cortical material in their immediate neighbourhoods. The MPC model can further help to explain other, poorly understood, aspects of hair growth and morphology. Separate bending and twisting mechanisms would be preferentially affected at the major or minor ellipsoidal sides of fibres, respectively, and together they exhaust the possibilities for influencing hair-form phenotypes. As such they suggest dialectic for hair-curvature development. We define a natural-dialectic (ND) which could take advantage of speculative aspects of dialectic, but would verify its input data and results by experimental methods. We use this as a top-down approach to first define routes by which hair bending or twisting may be brought about and then review evidence in support of such routes. In particular we consider the wingless (Wnt) and mammalian target of rapamycin (mTOR) pathways as paradigm pathways for molecular hair bending and twisting mechanisms, respectively. In addition to the Wnt canonical pathway, the Wnt/Ca(2+) and planar cell polarity (PCP) pathways

  16. Role of somatostatin receptor-2 in gentamicin-induced auditory hair cell loss in the Mammalian inner ear.

    Directory of Open Access Journals (Sweden)

    Yves Brand

    Full Text Available Hair cells and spiral ganglion neurons of the mammalian auditory system do not regenerate, and their loss leads to irreversible hearing loss. Aminoglycosides induce auditory hair cell death in vitro, and evidence suggests that phosphatidylinositol-3-kinase/Akt signaling opposes gentamicin toxicity via its downstream target, the protein kinase Akt. We previously demonstrated that somatostatin-a peptide with hormone/neurotransmitter properties-can protect hair cells from gentamicin-induced hair cell death in vitro, and that somatostatin receptors are expressed in the mammalian inner ear. However, it remains unknown how this protective effect is mediated. In the present study, we show a highly significant protective effect of octreotide (a drug that mimics and is more potent than somatostatin on gentamicin-induced hair cell death, and increased Akt phosphorylation in octreotide-treated organ of Corti explants in vitro. Moreover, we demonstrate that somatostatin receptor-1 knockout mice overexpress somatostatin receptor-2 in the organ of Corti, and are less susceptible to gentamicin-induced hair cell loss than wild-type or somatostatin-1/somatostatin-2 double-knockout mice. Finally, we show that octreotide affects auditory hair cells, enhances spiral ganglion neurite number, and decreases spiral ganglion neurite length.

  17. Transdifferentiation of Human Hair Follicle Mesenchymal Stem Cells into Red Blood Cells by OCT4

    Directory of Open Access Journals (Sweden)

    Zhijing Liu

    2015-01-01

    Full Text Available Shortage of red blood cells (RBCs, erythrocytes can have potentially life-threatening consequences for rare or unusual blood type patients with massive blood loss resulting from various conditions. Erythrocytes have been derived from human pluripotent stem cells (PSCs, but the risk of potential tumorigenicity cannot be ignored, and a majority of these cells produced from PSCs express embryonic ε- and fetal γ-globins with little or no adult β-globin and remain nucleated. Here we report a method to generate erythrocytes from human hair follicle mesenchymal stem cells (hHFMSCs by enforcing OCT4 gene expression and cytokine stimulation. Cells generated from hHFMSCs expressed mainly the adult β-globin chain with minimum level of the fetal γ-globin chain. Furthermore, these cells also underwent multiple maturation events and formed enucleated erythrocytes with a biconcave disc shape. Gene expression analyses showed that OCT4 regulated the expression of genes associated with both pluripotency and erythroid development during hHFMSC transdifferentiation toward erythroid cells. These findings show that mature erythrocytes can be generated from adult somatic cells, which may serve as an alternative source of RBCs for potential autologous transfusion.

  18. Espins and the actin cytoskeleton of hair cell stereocilia and sensory cell microvilli

    Science.gov (United States)

    Sekerková, Gabriella; Zheng, Lili; Loomis, Patricia A.; Mugnaini, Enrico; Bartles, James R.

    2008-01-01

    The espins are novel actin-bundling proteins that are produced in multiple isoforms from a single gene. They are present at high concentration in the parallel actin bundle of hair cell stereocilia and are the target of deafness mutations in mice and humans. Espins are also enriched in the microvilli of taste receptor cells, solitary chemoreceptor cells, vomeronasal sensory neurons and Merkel cells, suggesting that espins play important roles in the microvillar projections of vertebrate sensory cells. Espins are potent actin-bundling proteins that are not inhibited by Ca2+. In cells, they efficiently elongate parallel actin bundles and, thereby, help determine the steady-state length of microvilli and stereocilia. Espins bind actin monomer via their WH2 domain and can assemble actin bundles in cells. Certain espin isoforms can also bind phosphatidylinositol 4,5-bisphosphate, profilins or SH3 proteins. These biological activities distinguish espins from other actin-bundling proteins and may make them well-suited to sensory cells. PMID:16909209

  19. Feasibility of human hair follicle-derived mesenchymal stem cells/CultiSpher(®)-G constructs in regenerative medicine.

    Science.gov (United States)

    Li, Pengdong; Liu, Feilin; Wu, Chunling; Jiang, Wenyue; Zhao, Guifang; Liu, Li; Bai, Tingting; Wang, Li; Jiang, Yixu; Guo, Lili; Qi, Xiaojuan; Kou, Junna; Fan, Ruirui; Hao, Deshun; Lan, Shaowei; Li, Yulin; Liu, Jin Yu

    2015-10-01

    The use of human mesenchymal stem cells (hMSCs) in cell therapies has increased the demand for strategies that allow efficient cell scale-up. Preliminary data on the three-dimensional (3D) spinner culture describing the potential use of microcarriers for hMSCs culture scale-up have been reported. We exploited a rich source of autologous stem cells (human hair follicle) and demonstrated the robust in vitro long-term expansion of human hair follicle-derived mesenchymal stem cells (hHF-MSCs) by using CultiSpher(®)-G microcarriers. We analyzed the feasibility of 3D culture by using hHF-MSCs/CultiSpher(®)-G microcarrier constructs for its potential applicability in regenerative medicine by comparatively analyzing the performance of hHF-MSCs adhered to the CultiSpher(®)-G microspheres in 3D spinner culture and those grown on the gelatin-coated plastic dishes (2D culture), using various assays. We showed that the hHF-MSCs seeded at various densities quickly adhered to and proliferated well on the microspheres, thus generating at least hundreds of millions of hHF-MSCs on 1 g of CultiSpher(®)-G within 12 days. This resulted in a cumulative cell expansion of greater than 26-fold. Notably, the maximum and average proliferation rates in 3D culture were significantly greater than that of the 2D culture. However, the hHF-MSCs from both the cultures retained surface marker and nestin expression, proliferation capacity and differentiation potentials toward adipocytes, osteoblasts and smooth muscle cells and showed no significant differences as evidenced by Edu incorporation, cell cycle, colony formation, apoptosis, biochemical quantification and qPCR assays.

  20. Inositol bisphosphate and inositol trisphosphate inhibit cell-to-cell passage of carboxyfluorescein in staminal hairs ofSetcreasea purpurea.

    Science.gov (United States)

    Tucker, E B

    1988-06-01

    pH-buffered carboxyfluorescein (Buffered-CF) alone (control), or Buffered-CF solutions containing one of the following: (1)D-myo-inositol (I); (2)D-myo-inositol 2-monophosphate (IP1); (3)D-myo-inositol 1,4-bisphosphate (IP2); (4)D-myo-inositol 1,4,5-trisphosphate (IP3); (5)D-fructose 2,6-diphosphate (F-2,6P2) were microinjected into the terminal cells of staminal hairs ofSetcreasea purpurea Boom. Passage of the CF from this terminal cell along the chain of cells towards the filament was monitored for 5 min using fluorescence microscopy and quantified using computer-assisted fluorescence-intensity video analysis. Cell-to-cell transport of CF in hairs microinjected with Buffered-CF containing either I, IP1 or F-2,6P2 was similar to that in hairs microinjected with Buffered-CF only. On the other hand, cell-to-cell transport of CF in hairs microinjected with Buffered-CF containing either IP2 or IP3 was inhibited. These results indicate that polyphosphoinositols may be involved in the regulation of intercellular transport of low-molecular-weight, hydrophilic molecules in plants.

  1. No Correlates for Somatic Motility in Freeze-Fractured Hair-Cell Membranes of Lizards and Birds

    Science.gov (United States)

    Köppl, C.; Forge, A.; Manley, G. A.

    2003-02-01

    It is not known whether active processes in mammals and non-mammals are due to the same underlying mechanism. To address this, we studied the size and density of particles in hair-cell membranes in mammals, in a lizard, the Tokay gecko, and in a bird, the barn owl. We surmised that if the prominent particles described in mammalian outer-hair-cell membranes are responsible for cochlear motility, a similar occurrence in non-mammalian hair cells would argue for similar mechanisms. Particle densities differed, however, substantially from those of mammals, suggesting that non-mammals have no membrane-based motility.

  2. Hair Follicle Dermal Sheath Derived Cells Improve Islet Allograft Survival without Systemic Immunosuppression

    Directory of Open Access Journals (Sweden)

    Xiaojie Wang

    2015-01-01

    Full Text Available Immunosuppressive drugs successfully prevent rejection of islet allografts in the treatment of type I diabetes. However, the drugs also suppress systemic immunity increasing the risk of opportunistic infection and cancer development in allograft recipients. In this study, we investigated a new treatment for autoimmune diabetes using naturally immune privileged, hair follicle derived, autologous cells to provide localized immune protection of islet allotransplants. Islets from Balb/c mouse donors were cotransplanted with syngeneic hair follicle dermal sheath cup cells (DSCC, group 1 or fibroblasts (FB, group 2 under the kidney capsule of immune-competent, streptozotocin induced, diabetic C57BL/6 recipients. Group 1 allografts survived significantly longer than group 2 (32.2 ± 12.2 versus 14.1 ± 3.3 days, P<0.001 without administration of any systemic immunosuppressive agents. DSCC reduced T cell activation in the renal lymph node, prevented graft infiltrates, modulated inflammatory chemokine and cytokine profiles, and preserved better beta cell function in the islet allografts, but no systemic immunosuppression was observed. In summary, DSCC prolong islet allograft survival without systemic immunosuppression by local modulation of alloimmune responses, enhancing of beta cell survival, and promoting of graft revascularization. This novel finding demonstrates the capacity of easily accessible hair follicle cells to be used as local immunosuppression agents in islet transplantation.

  3. Basal cell carcinoma preferentially arises from stem cells within hair follicle and mechanosensory niches.

    Science.gov (United States)

    Peterson, Shelby C; Eberl, Markus; Vagnozzi, Alicia N; Belkadi, Abdelmadjid; Veniaminova, Natalia A; Verhaegen, Monique E; Bichakjian, Christopher K; Ward, Nicole L; Dlugosz, Andrzej A; Wong, Sunny Y

    2015-04-02

    Basal cell carcinoma (BCC) is characterized by frequent loss of PTCH1, leading to constitutive activation of the Hedgehog pathway. Although the requirement for Hedgehog in BCC is well established, the identity of disease-initiating cells and the compartments in which they reside remain controversial. By using several inducible Cre drivers to delete Ptch1 in different cell compartments in mice, we show here that multiple hair follicle stem cell populations readily develop BCC-like tumors. In contrast, stem cells within the interfollicular epidermis do not efficiently form tumors. Notably, we observed that innervated Gli1-expressing progenitors within mechanosensory touch dome epithelia are highly tumorigenic. Sensory nerves activate Hedgehog signaling in normal touch domes, while denervation attenuates touch dome-derived tumors. Together, our studies identify varying tumor susceptibilities among different stem cell populations in the skin, highlight touch dome epithelia as "hot spots" for tumor formation, and implicate cutaneous nerves as mediators of tumorigenesis. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Regulators of Tfh cell differentiation

    Directory of Open Access Journals (Sweden)

    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.

  5. A role for CSLD3 during cell-wall synthesis in apical plasma membranes of tip-growing root-hair cells.

    Science.gov (United States)

    Park, Sungjin; Szumlanski, Amy L; Gu, Fangwei; Guo, Feng; Nielsen, Erik

    2011-07-17

    In plants, cell shape is defined by the cell wall, and changes in cell shape and size are dictated by modification of existing cell walls and deposition of newly synthesized cell-wall material. In root hairs, expansion occurs by a process called tip growth, which is shared by root hairs, pollen tubes and fungal hyphae. We show that cellulose-like polysaccharides are present in root-hair tips, and de novo synthesis of these polysaccharides is required for tip growth. We also find that eYFP-CSLD3 proteins, but not CESA cellulose synthases, localize to a polarized plasma-membrane domain in root hairs. Using biochemical methods and genetic complementation of a csld3 mutant with a chimaeric CSLD3 protein containing a CESA6 catalytic domain, we provide evidence that CSLD3 represents a distinct (1→4)-β-glucan synthase activity in apical plasma membranes during tip growth in root-hair cells.

  6. Mechanoelectrical transduction of adult outer hair cells studied in a gerbil hemicochlea.

    Science.gov (United States)

    He, David Z Z; Jia, Shuping; Dallos, Peter

    2004-06-17

    Sensory receptor cells of the mammalian cochlea are morphologically and functionally dichotomized. Inner hair cells transmit auditory information to the brain, whereas outer hair cells (OHC) amplify the mechanical signal, which is then transduced by inner hair cells. Amplification by OHCs is probably mediated by their somatic motility in a mechanical feedback process. OHC motility in vivo is thought to be driven by the cell's receptor potential. The first steps towards the generation of the receptor potential are the deflection of the stereociliary bundle, and the subsequent flow of transducer current through the mechanosensitive transducer channels located at their tips. Quantitative relations between transducer currents and basilar membrane displacements are lacking, as well as their variation along the cochlear length. To address this, we simultaneously recorded OHC transducer currents (or receptor potentials) and basilar membrane motion in an excised and bisected cochlea, the hemicochlea. This preparation permits recordings from adult OHCs at various cochlear locations while the basilar membrane is mechanically stimulated. Furthermore, the stereocilia are deflected by the same means of stimulation as in vivo. Here we show that asymmetrical transducer currents and receptor potentials are significantly larger than previously thought, they possess a highly restricted dynamic range and strongly depend on cochlear location.

  7. The function and molecular identity of inward rectifier channels in vestibular hair cells of the mouse inner ear

    Science.gov (United States)

    Levin, Michaela E.

    2012-01-01

    Inner ear hair cells respond to mechanical stimuli with graded receptor potentials. These graded responses are modulated by a host of voltage-dependent currents that flow across the basolateral membrane. Here, we examine the molecular identity and the function of a class of voltage-dependent ion channels that carries the potassium-selective inward rectifier current known as IK1. IK1 has been identified in vestibular hair cells of various species, but its molecular composition and functional contributions remain obscure. We used quantitative RT-PCR to show that the inward rectifier gene, Kir2.1, is highly expressed in mouse utricle between embryonic day 15 and adulthood. We confirmed Kir2.1 protein expression in hair cells by immunolocalization. To examine the molecular composition of IK1, we recorded voltage-dependent currents from type II hair cells in response to 50-ms steps from −124 to −54 in 10-mV increments. Wild-type cells had rapidly activating inward currents with reversal potentials close to the K+ equilibrium potential and a whole-cell conductance of 4.8 ± 1.5 nS (n = 46). In utricle hair cells from Kir2.1-deficient (Kir2.1−/−) mice, IK1 was absent at all stages examined. To identify the functional contribution of Kir2.1, we recorded membrane responses in current-clamp mode. Hair cells from Kir2.1−/− mice had significantly (P < 0.001) more depolarized resting potentials and larger, slower membrane responses than those of wild-type cells. These data suggest that Kir2.1 is required for IK1 in type II utricle hair cells and contributes to hyperpolarized resting potentials and fast, small amplitude receptor potentials in response to current inputs, such as those evoked by hair bundle deflections. PMID:22496522

  8. An allosteric gating model recapitulates the biophysical properties of IK,L expressed in mouse vestibular type I hair cells.

    Science.gov (United States)

    Spaiardi, Paolo; Tavazzani, Elisa; Manca, Marco; Milesi, Veronica; Russo, Giancarlo; Prigioni, Ivo; Marcotti, Walter; Magistretti, Jacopo; Masetto, Sergio

    2017-11-01

    Vestibular type I and type II hair cells and their afferent fibres send information to the brain regarding the position and movement of the head. The characteristic feature of type I hair cells is the expression of a low-voltage-activated outward rectifying K + current, I K,L , whose biophysical properties and molecular identity are still largely unknown. In vitro, the afferent nerve calyx surrounding type I hair cells causes unstable intercellular K + concentrations, altering the biophysical properties of I K,L . We found that in the absence of the calyx, I K,L in type I hair cells exhibited unique biophysical activation properties, which were faithfully reproduced by an allosteric channel gating scheme. These results form the basis for a molecular and pharmacological identification of I K,L . Type I and type II hair cells are the sensory receptors of the mammalian vestibular epithelia. Type I hair cells are characterized by their basolateral membrane being enveloped in a single large afferent nerve terminal, named the calyx, and by the expression of a low-voltage-activated outward rectifying K + current, I K,L . The biophysical properties and molecular profile of I K,L are still largely unknown. By using the patch-clamp whole-cell technique, we examined the voltage- and time-dependent properties of I K,L in type I hair cells of the mouse semicircular canal. We found that the biophysical properties of I K,L were affected by an unstable K + equilibrium potential (V eq K + ). Both the outward and inward K + currents shifted V eq K + consistent with K + accumulation or depletion, respectively, in the extracellular space, which we attributed to a residual calyx attached to the basolateral membrane of the hair cells. We therefore optimized the hair cell dissociation protocol in order to isolate mature type I hair cells without their calyx. In these cells, the uncontaminated I K,L showed a half-activation at -79.6 mV and a steep voltage dependence (2.8 mV). I K,L also

  9. Differential relationships between chronic hormone profiles in pregnancy and maternal investment in rhesus monkey mothers with hair loss in the neonatal period.

    Science.gov (United States)

    Dettmer, Amanda M; Rosenberg, Kendra; Menard, Mark T; El-Mallah, Saif N; Woodward, Ruth A; Suomi, Stephen J; Meyer, Jerrold S

    2017-01-01

    Hair loss is commonly used as an indicator of well being in primate facilities, yet it has been shown to also occur in otherwise healthy pregnant and postpartum females. There is significant variability in the incidence of hair loss during these important developmental periods, reasons for which remain unclear. We studied female rhesus monkeys (Macaca mulatta, n = 47) with and without hair loss in pregnancy/postpartum. We hypothesized that, similar to previously published reports, pregnancy would result in an increased likelihood of hair loss, and that hair loss would be correlated with higher hair cortisol concentrations (HCCs). We further hypothesized that hair loss among pregnant females is related to differential maternal investment. We studied a subset of monkeys (n = 26) from mid-to-late pregnancy through peak lactation, some of which exhibited hair loss in the perinatal period (n = 15), and some of which did not (n = 11). We examined fetal measurements, infant birth weight, infant growth rate, and milk yield volume (MYV) in the first 30 days as indices of investment. We found that pregnant monkeys showed a greater incidence of hair loss across the study year (χ 2 (2)  = 6.55, P = 0.038), and that mothers with hair loss had significantly higher HCCs in pregnancy than those without (F (2,28)  = 3.8, P = 0.017, η p 2  = 0.21). HCCs in pregnancy were correlated with severity of hair loss in the neonatal period (r (37)  = 0.42, P = 0.008). Moreover, HCCs in pregnancy were positively correlated with infant birth weight (r (12)  = 0.56, P = 0.038), infant growth rate (r (12)  = 0.64, P = 0.014), and MYV (r (11)  = 0.85, P hair loss in some monkeys, especially during the birthing season, may be a signal of greater physiological stress during pregnancy and differential investment by mothers to their offspring. Am. J. Primatol. 79:e22489, 2017. © 2015 Wiley Periodicals, Inc. © 2016 Wiley Periodicals

  10. Interactions between hair cells shape spontaneous otoacoustic emissions in a model of the tokay gecko's cochlea.

    Directory of Open Access Journals (Sweden)

    Michael Gelfand

    2010-06-01

    Full Text Available The hearing of tetrapods including humans is enhanced by an active process that amplifies the mechanical inputs associated with sound, sharpens frequency selectivity, and compresses the range of responsiveness. The most striking manifestation of the active process is spontaneous otoacoustic emission, the unprovoked emergence of sound from an ear. Hair cells, the sensory receptors of the inner ear, are known to provide the energy for such emissions; it is unclear, though, how ensembles of such cells collude to power observable emissions.We have measured and modeled spontaneous otoacoustic emissions from the ear of the tokay gecko, a convenient experimental subject that produces robust emissions. Using a van der Pol formulation to represent each cluster of hair cells within a tonotopic array, we have examined the factors that influence the cooperative interaction between oscillators.A model that includes viscous interactions between adjacent hair cells fails to produce emissions similar to those observed experimentally. In contrast, elastic coupling yields realistic results, especially if the oscillators near the ends of the array are weakened so as to minimize boundary effects. Introducing stochastic irregularity in the strength of oscillators stabilizes peaks in the spectrum of modeled emissions, further increasing the similarity to the responses of actual ears. Finally, and again in agreement with experimental findings, the inclusion of a pure-tone external stimulus repels the spectral peaks of spontaneous emissions. Our results suggest that elastic coupling between oscillators of slightly differing strength explains several properties of the spontaneous otoacoustic emissions in the gecko.

  11. Interactions between hair cells shape spontaneous otoacoustic emissions in a model of the tokay gecko's cochlea.

    Science.gov (United States)

    Gelfand, Michael; Piro, Oreste; Magnasco, Marcelo O; Hudspeth, A J

    2010-06-15

    The hearing of tetrapods including humans is enhanced by an active process that amplifies the mechanical inputs associated with sound, sharpens frequency selectivity, and compresses the range of responsiveness. The most striking manifestation of the active process is spontaneous otoacoustic emission, the unprovoked emergence of sound from an ear. Hair cells, the sensory receptors of the inner ear, are known to provide the energy for such emissions; it is unclear, though, how ensembles of such cells collude to power observable emissions. We have measured and modeled spontaneous otoacoustic emissions from the ear of the tokay gecko, a convenient experimental subject that produces robust emissions. Using a van der Pol formulation to represent each cluster of hair cells within a tonotopic array, we have examined the factors that influence the cooperative interaction between oscillators. A model that includes viscous interactions between adjacent hair cells fails to produce emissions similar to those observed experimentally. In contrast, elastic coupling yields realistic results, especially if the oscillators near the ends of the array are weakened so as to minimize boundary effects. Introducing stochastic irregularity in the strength of oscillators stabilizes peaks in the spectrum of modeled emissions, further increasing the similarity to the responses of actual ears. Finally, and again in agreement with experimental findings, the inclusion of a pure-tone external stimulus repels the spectral peaks of spontaneous emissions. Our results suggest that elastic coupling between oscillators of slightly differing strength explains several properties of the spontaneous otoacoustic emissions in the gecko.

  12. Conditional deletion of pejvakin in adult outer hair cells causes progressive hearing loss in mice.

    Science.gov (United States)

    Harris, Suzan L; Kazmierczak, Marcin; Pangršič, Tina; Shah, Prahar; Chuchvara, Nadiya; Barrantes-Freer, Alonso; Moser, Tobias; Schwander, Martin

    2017-03-06

    Mutations in the Pejvakin (Pjvk) gene cause autosomal recessive hearing loss DFNB59 with audiological features of auditory neuropathy spectrum disorder (ANSD) or cochlear dysfunction. The precise mechanisms underlying the variable clinical phenotypes of DFNB59 remain unclear. Here, we demonstrate that mice with conditional ablation of the Pjvk gene in all sensory hair cells or only in outer hair cells (OHCs) show similar auditory phenotypes with early-onset profound hearing loss. By contrast, loss of Pjvk in adult OHCs causes a slowly progressive hearing loss associated with OHC degeneration and delayed loss of inner hair cells (IHCs), indicating a primary role for pejvakin in regulating OHC function and survival. Consistent with this model, synaptic transmission at the IHC ribbon synapse is largely unaffected in sirtaki mice that carry a C-terminal deletion mutation in Pjvk. Using the C-terminal domain of pejvakin as bait, we identified in a cochlear cDNA library ROCK2, an effector for the small GTPase Rho, and the scaffold protein IQGAP1, involved in modulating actin dynamics. Both ROCK2 and IQGAP1 associate via their coiled-coil domains with pejvakin. We conclude that pejvakin is required to sustain OHC activity and survival in a cell-autonomous manner likely involving regulation of Rho signaling. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  13. Effects of neuroactive steroids on cochlear hair cell death induced by gentamicin.

    Science.gov (United States)

    Nakamagoe, Mariko; Tabuchi, Keiji; Nishimura, Bungo; Hara, Akira

    2011-12-11

    As neuroactive steroids, sex steroid hormones have non-reproductive effects. We previously reported that 17β-estradiol (βE2) had protective effects against gentamicin (GM) ototoxicity in the cochlea. In the present study, we examined whether the protective action of βE2 on GM ototoxicity is mediated by the estrogen receptor (ER) and whether other estrogens (17α-estradiol (αE2), estrone (E1), and estriol (E3)) and other neuroactive steroids, dehydroepiandrosterone (DHEA) and progesterone (P), have similar protective effects. The basal turn of the organ of Corti was dissected from Sprague-Dawley rats and cultured in a medium containing 100 μM GM for 48h. The effects of βE2 and ICI 182,780, a selective ER antagonist, were examined. In addition, the effects of other estrogens, DHEA and P were tested using this culture system. Loss of outer hair cells induced by GM exposure was compared among groups. βE2 exhibited a protective effect against GM ototoxicity, but its protective effect was antagonized by ICI 182,780. αE2, E1, and E3 also protected hair cells against gentamicin ototoxicity. DHEA showed a protective effect; however, the addition of ICI 182,780 did not affect hair cell loss. P did not have any effect on GM-induced outer hair cell death. The present findings suggest that estrogens and DHEA are protective agents against GM ototoxicity. The results of the ER antagonist study also suggest that the protective action of βE2 is mediated via ER but that of DHEA is not related to its conversion to estrogen and binding to ER. Further studies on neuroactive steroids may lead to new insights regarding cochlear protection. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Interactions between Hair Cells Shape Spontaneous Otoacoustic Emissions in a Model of the Tokay Gecko's Cochlea

    OpenAIRE

    Gelfand, Michael; Piro, Oreste; Magnasco, Marcelo O.; Hudspeth, A. J.

    2010-01-01

    Background The hearing of tetrapods including humans is enhanced by an active process that amplifies the mechanical inputs associated with sound, sharpens frequency selectivity, and compresses the range of responsiveness. The most striking manifestation of the active process is spontaneous otoacoustic emission, the unprovoked emergence of sound from an ear. Hair cells, the sensory receptors of the inner ear, are known to provide the energy for such emissions; it is unclear, though, how ens...

  15. Hair Removal

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Hair Removal KidsHealth / For Teens / Hair Removal What's in ... you need any of them? Different Types of Hair Before removing hair, it helps to know about ...

  16. Hair Transplants

    Science.gov (United States)

    ... Search Skin Experts Skin Treatments Hair Transplants Share » HAIR TRANSPLANTS Before (left) and after (right) - front of ... transplant. Photo courtesy of N. Sadick What are hair transplants? In punch transplanting, a plug containing hair ...

  17. Your Hair

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Your Hair KidsHealth / For Kids / Your Hair What's in this ... eyes from sweat dripping down from your forehead. Hair Comes From Where? Whether hair is growing out ...

  18. Effect of inner and outer hair cell lesions on electrically evoked otoacoustic emissions.

    Science.gov (United States)

    Reyes, S; Ding, D; Sun, W; Salvi, R

    2001-08-01

    When the cochlea is stimulated by a sinusoidal current, the inner ear emits an acoustic signal at the stimulus frequency, termed the electrically evoked otoacoustic emission (EEOAE). Recent studies have found EEOAEs in birds lacking outer hair cells (OHCs), raising the possibility that other types of hair cells, including inner hair cells (IHCs), may generate EEOAEs. To determine the relative contribution of IHCs and OHCs to the generation of the EEOAE, we measured the amplitude of EEOAEs, distortion product otoacoustic emissions (DPOAEs), the cochlear microphonic (CM) and the compound action potential (CAP) in normal chinchillas and chinchillas with IHC lesions or IHC plus OHC lesions induced by carboplatin. Selective IHC loss had little or no effect on CM amplitude and caused a slight reduction in mean DPOAE amplitude. However, IHC loss resulted in a massive reduction in CAP amplitude. Importantly, selective IHC lesions did not reduce EEOAE amplitude, but instead, EEOAE amplitude increased at high frequencies. When both IHCs and OHCs were destroyed, the amplitude of the CM, DPOAE and EEOAE all decreased. The increase in EEOAE amplitude seen with IHC loss may be due to (1) loss of tonic efferent activity to the OHCs, (2) change in the mechanical properties of the cochlea or (3) elimination of EEOAEs produced by IHCs in phase opposition to those from OHCs.

  19. Ethanol extract of Piper longum L. attenuates gentamicin-induced hair cell loss in neonatal cochlea cultures.

    Science.gov (United States)

    Du, Xiao Fei; Song, Jae-Jun; Hong, Seungug; Kim, Jihye

    2012-06-01

    Piper longum L. (PL), also as known as long pepper, a well-known spice and traditional medicine in Asia and Pacific islands, has been reported to exhibit wide spectrum activity including antioxidant activity. However, little information is available on its protective effect on gentamicin (GM) induced ototoxicity which is commonly regarded as being mediated by reactive oxygen species and reactive nitrogen species. This study was undertaken to investigate the protective effect of PL ethanol extract on gentamicin-induced hair cell loss in neonatal cochlea cultures. Cochlea cultures from postnatal day 2-3 mice were used for analysis of the protective effects of PL against gentamicin-induced hair cell loss by phalloidin staining. E. coil cultures were used to determine whether PL interferes with the antibiotic activity of GM. Nitric oxide (NO)-scavenging activity of PL was also measured in vitro. GM induced significant dose-dependent hair cell loss in cochlea cultures. However, without interfering with the antibiotic activity of GM, PL showed a significant and concentration-dependent protective effect against GM-induced hair cell loss, and hair cells retained their stereocilia well. In addition, PL expressed direct scavenging activity toward NO radical liberated within solution of sodium nitroprusside. These findings demonstrate the protective effect of PL on GM-induced hair cell loss in neonatal cochlea cultures, and suggest that it might be of therapeutic benefit for treatment of GM-induced ototoxicity.

  20. Ectodermal Differentiation of Wharton's Jelly Mesenchymal Stem Cells for Tissue Engineering and Regenerative Medicine Applications.

    Science.gov (United States)

    Jadalannagari, Sushma; Aljitawi, Omar S

    2015-06-01

    Mesenchymal stem cells (MSCs) from Wharton's jelly (WJ) of the human umbilical cord are perinatal stem cells that have self-renewal ability, extended proliferation potential, immunosuppressive properties, and are accordingly excellent candidates for tissue engineering. These MSCs are unique, easily accessible, and a noncontroversial cell source of regeneration in medicine. Wharton's jelly mesenchymal stem cells (WJMSCs) are multipotent and capable of multilineage differentiation into cells like adipocytes, bone, cartilage, and skeletal muscle upon exposure to appropriate conditions. The ectoderm is one of the three primary germ layers found in the very early embryo that differentiates into the epidermis, nervous system (spine, peripheral nerves, brain), and exocrine glands (mammary, sweat, salivary, and lacrimal glands). Accumulating evidence shows that MSCs obtained from WJ have an ectodermal differentiation potential. The current review examines this differentiation potential of WJMSC into the hair follicle, skin, neurons, and sweat glands along with discussing the potential utilization of such differentiation in regenerative medicine.

  1. Mobilizing Transit-Amplifying Cell-Derived Ectopic Progenitors Prevents Hair Loss from Chemotherapy or Radiation Therapy.

    Science.gov (United States)

    Huang, Wen-Yen; Lai, Shih-Fan; Chiu, Hsien-Yi; Chang, Michael; Plikus, Maksim V; Chan, Chih-Chieh; Chen, You-Tzung; Tsao, Po-Nien; Yang, Tsung-Lin; Lee, Hsuan-Shu; Chi, Peter; Lin, Sung-Jan

    2017-11-15

    Genotoxicity-induced hair loss from chemotherapy and radiotherapy is often encountered in cancer treatment, and there is a lack of effective treatment. In growing hair follicles (HF), quiescent stem cells (SC) are maintained in the bulge region, and hair bulbs at the base contain rapidly dividing, yet genotoxicity-sensitive transit-amplifying cells (TAC) that maintain hair growth. How genotoxicity-induced HF injury is repaired remains unclear. We report here that HFs mobilize ectopic progenitors from distinct TAC compartments for regeneration in adaptation to the severity of dystrophy induced by ionizing radiation (IR). Specifically, after low-dose IR, keratin 5 + basal hair bulb progenitors, rather than bulge SCs, were quickly activated to replenish matrix cells and regenerated all concentric layers of HFs, demonstrating their plasticity. After high-dose IR, when both matrix and hair bulb cells were depleted, the surviving outer root sheath cells rapidly acquired an SC-like state and fueled HF regeneration. Their progeny then homed back to SC niche and supported new cycles of HF growth. We also revealed that IR induced HF dystrophy and hair loss and suppressed WNT signaling in a p53- and dose-dependent manner. Augmenting WNT signaling attenuated the suppressive effect of p53 and enhanced ectopic progenitor proliferation after genotoxic injury, thereby preventing both IR- and cyclophosphamide-induced alopecia. Hence, targeted activation of TAC-derived progenitor cells, rather than quiescent bulge SCs, for anagen HF repair can be a potential approach to prevent hair loss from chemotherapy and radiotherapy. Cancer Res; 77(22); 6083-96. ©2017 AACR . ©2017 American Association for Cancer Research.

  2. Diffuse large B-cell lymphoma chemotherapy reveals a combined immunodeficiency syndrome in cartilage hair hypoplasia.

    Science.gov (United States)

    Nguyen, Alexandre; Martin Silva, Nicolas; de Boysson, Hubert; Damaj, Gandhi; Aouba, Achille

    2018-04-24

    Cartilage hair hypoplasia (CHH) is a rare autosomal recessive ribosomopathy characterised by skeletal and integumentary system manifestations. It may also present with varied forms and intensities of haematopoietic and/or immune disorders. We report a 27-year-old female who presented a picture of combined immunodeficiency after receiving an adriamycin-based chemotherapy regimen followed by autologous stem cell transplantation. Her medical history indicated neonatal dwarfism, recurrent ear, nose and throat and respiratory infections, and hypogammaglobulinaemia, which were suggestive of a primary minor B-cell immune deficiency. Taken together, the diagnosis of cartilage hair hypoplasia was suspected and confirmed by means of molecular biological analysis. Here, we discuss the causal relationship and molecular mechanisms existing between both primary immunodeficiency and lymphoma conditions and between chemotherapy cytotoxicity and aggravation of the immune system and associated hematopoietic dysfunction, considering the role of all these components in light of the initially undiagnosed cartilage hair hypoplasia. Finally, this case highlights the importance of screening for primary immunodeficiencies in the setting of a diagnosis of lymphoma and/or dwarfism; moreover, CHH must be distinguished from other causes of small size; its diagnosis and complete check-up must include the molecular characterisation, and its management must be global in collaboration with haematologists, immunologists and internists.

  3. MicroRNA-148b promotes proliferation of hair follicle cells by targeting NFAT5

    Directory of Open Access Journals (Sweden)

    Wanbao YANG,Qinqun LI,Bo SU,Mei YU

    2016-03-01

    Full Text Available MicroRNAs (miRNAs, small non-coding RNAs, are involved in many aspects of biological processes. Previous studies have indicated that miRNAs are important for hair follicle development and growth. In our study, we found by qRT-PCR that miR-148b was significantly upregulated in sheep wool follicle bulbs in anagen phase compared with the telogen phase of the hair follicle cycle. Overexpression of miR-148b promoted proliferation of both HHDPC and HHGMC. By using the TOPFlash system we demonstrated that miR-148b could activate Wnt/β-catenin pathway and b-catenin, cycD, c-jun and PPARD were consistently upregulated accordingly. Furthermore, transcript factor nuclear factor of activated T cells type 5 (NFAT5 and Wnt10b were predicted to be the target of miR-148b and this was substantiated using a Dual-Luciferase reporter system. Subsequently NFAT5 was further identified as the target of miR-148b using western blotting. These results were considered to indicate that miR-148b could activate the Wnt/β-catenin signal pathway by targeting NFAT5 to promote the proliferation of human hair follicle cells.

  4. Hair cell regeneration or the expression of related factors that regulate the fate specification of supporting cells in the cochlear ducts of embryonic and posthatch chickens.

    Science.gov (United States)

    Jiang, Lingling; Jin, Ran; Xu, Jincao; Ji, Yubin; Zhang, Meiguang; Zhang, Xuebo; Zhang, Xinwen; Han, Zhongming; Zeng, Shaoju

    2016-02-01

    Hair cells in posthatch chickens regenerate spontaneously through mitosis or the transdifferentiation of supporting cells in response to antibiotic injury. However, how embryonic chicken cochleae respond to antibiotic treatment remains unknown. This study is the first to indicate that unlike hair cells in posthatch chickens, the auditory epithelium was free from antibiotic injury (25-250 mg gentamicin/kg) in embryonic chickens, although FITC-conjugated gentamicin actually reached embryonic hair cells. Next, we examined and counted the cells and performed labeling for BrdU, Sox2, Atoh1/Math1, PV or p27(kip1) (triple or double labeling) in the injured cochlea ducts after gentamicin treatment at 2 h (h), 15 h, 24 h, 2 days (d), 3 d and 7 d after BrdU treatment in posthatch chickens. Our results indicated that following gentamicin administration, proliferating cells (BrdU+) were labeled for Atoh1/Math1 in the damaged areas 3d after gentamicin administration, whereas hair cells (PV+) renewed through mitosis (BrdU+) or direct transdifferentiation (BrdU-) were evident only after 5 d of gentamicin administration. In addition, Sox2 expression was up-regulated in triggered supporting cells at an early stage of regeneration, but stopped at the advent of mature hair cells. Our study also indicated that p27(kip1) was expressed in both hair cells and supporting cells but was down-regulated in a subgroup of the supporting cells that gave rise to hair cells. These data and the obtained dynamic changes of the cells labeled for BrdU, Sox2, Atoh1/Math1, PV or p27(kip1) are useful for understanding supporting cell behaviors and their fate specification during hair cell regeneration. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Noise-Induced Loss of Hair Cells and Cochlear Synaptopathy Are Mediated by the Activation of AMPK.

    Science.gov (United States)

    Hill, Kayla; Yuan, Hu; Wang, Xianren; Sha, Su-Hua

    2016-07-13

    Noise-induced hearing loss (NIHL) is a major unresolved public health problem. Here, we investigate pathomechanisms of sensory hair cell death and suggest a novel target for protective intervention. Cellular survival depends upon maintenance of energy homeostasis, largely by AMP-activated protein kinase (AMPK). In response to a noise exposure in CBA/J mice, the levels of phosphorylated AMPKα increased in hair cells in a noise intensity-dependent manner. Inhibition of AMPK via siRNA or the pharmacological inhibitor compound C attenuated noise-induced loss of outer hair cells (OHCs) and synaptic ribbons, and preserved auditory function. Additionally, noise exposure increased the activity of the upstream AMPK kinase liver kinase B1 (LKB1) in cochlear tissues. The inhibition of LKB1 by siRNA attenuated the noise-increased phosphorylation of AMPKα in OHCs, reduced the loss of inner hair cell synaptic ribbons and OHCs, and protected against NIHL. These results indicate that noise exposure induces hair cell death and synaptopathy by activating AMPK via LKB1-mediated pathways. Targeting these pathways may provide a novel route to prevent NIHL. Our results demonstrate for the first time that the activation of AMP-activated protein kinase (AMPK) α in sensory hair cells is noise intensity dependent and contributes to noise-induced hearing loss by mediating the loss of inner hair cell synaptic ribbons and outer hair cells. Noise induces the phosphorylation of AMPKα1 by liver kinase B1 (LKB1), triggered by changes in intracellular ATP levels. The inhibition of AMPK activation by silencing AMPK or LKB1, or with the pharmacological inhibitor compound C, reduced outer hair cell and synaptic ribbon loss as well as noise-induced hearing loss. This study provides new insights into mechanisms of noise-induced hearing loss and suggests novel interventions for the prevention of the loss of sensory hair cells and cochlear synaptopathy. Copyright © 2016 the authors 0270-6474/16/367497-14$15.00/0.

  6. Simulation of Cell Patterning Triggered by Cell Death and Differential Adhesion in Drosophila Wing.

    Science.gov (United States)

    Nagai, Tatsuzo; Honda, Hisao; Takemura, Masahiko

    2018-02-27

    The Drosophila wing exhibits a well-ordered cell pattern, especially along the posterior margin, where hair cells are arranged in a zigzag pattern in the lateral view. Based on an experimental result observed during metamorphosis of Drosophila, we considered that a pattern of initial cells autonomously develops to the zigzag pattern through cell differentiation, intercellular communication, and cell death (apoptosis) and performed computer simulations of a cell-based model of vertex dynamics for tissues. The model describes the epithelial tissue as a monolayer cell sheet of polyhedral cells. Their vertices move according to equations of motion, minimizing the sum total of the interfacial and elastic energies of cells. The interfacial energy densities between cells are introduced consistently with an ideal zigzag cell pattern, extracted from the experimental result. The apoptosis of cells is modeled by gradually reducing their equilibrium volume to zero and by assuming that the hair cells prohibit neighboring cells from undergoing apoptosis. Based on experimental observations, we also assumed wing elongation along the proximal-distal axis. Starting with an initial cell pattern similar to the micrograph experimentally obtained just before apoptosis, we carried out the simulations according to the model mentioned above and successfully reproduced the ideal zigzag cell pattern. This elucidates a physical mechanism of patterning triggered by cell apoptosis theoretically and exemplifies, to our knowledge, a new framework to study apoptosis-induced patterning. We conclude that the zigzag cell pattern is formed by an autonomous communicative process among the participant cells. Copyright © 2018 Biophysical Society. All rights reserved.

  7. Magnetic Nanoparticles as Mechanical Actuators of Inner Ear Hair Cells

    Science.gov (United States)

    2016-01-13

    Nanoparticles: A Precision Tool for Cell Imaging and Activations”, Seminar, 5th Frontier Scientist Workshop, KAST , Hotel Novotel London West, London, UK, Oct...of Science and Technology ( KAST ), Westin Chosun Hotel, Seoul, Korea, Nov. 2nd, 2012. “Rational Design of Nanoparticles for Biomedical and Energy

  8. Inhibition of nitrogen-fixing activity of the cyanobiont affects the localization of glutamine synthetase in hair cells of Azolla.

    Science.gov (United States)

    Uheda, Eiji; Maejima, Kazuhiro

    2009-10-15

    In the Azolla-Anabaena association, the host plant Azolla efficiently incorporates and assimilates ammonium ions that are released from the nitrogen-fixing cyanobiont, probably via glutamine synthetase (GS; EC 6.3.1.2) in hair cells, which are specialized cells protruding into the leaf cavity. In order to clarify the regulatory mechanism underlying ammonium assimilation in the Azolla-Anabaena association, Azolla plants were grown under an argon environment (Ar), in which the nitrogen-fixing activity of the cyanobiont was inhibited specifically and completely. The localization of GS in hair cells was determined by immunoelectron microscopy and quantitative analysis of immunogold labeling. Azolla plants grew healthily under Ar when nitrogen sources, such as NO(3)(-) and NH(4)(+), were provided in the growth medium. Both the number of cyanobacterial cells per leaf and the heterocyst frequency of the plants under Ar were similar to those of plants in a nitrogen environment (N(2)). In hair cells of plants grown under Ar, regardless of the type of nitrogen source provided, only weak labeling of GS was observed in the cytoplasm and in chloroplasts. In contrast, in hair cells of plants grown under N(2), abundant labeling of GS was observed in both sites. These findings indicate that specific inhibition of the nitrogen-fixing activity of the cyanobiont affects the localization of GS isoenzymes. Ammonium fixed and released by the cyanobiont could stimulate GS synthesis in hair cells. Simultaneously, the abundant GS, probably GS1, in these cells, could assimilate ammonium rapidly.

  9. Selective deletion of cochlear hair cells causes rapid age-dependent changes in spiral ganglion and cochlear nucleus neurons.

    Science.gov (United States)

    Tong, Ling; Strong, Melissa K; Kaur, Tejbeer; Juiz, Jose M; Oesterle, Elizabeth C; Hume, Clifford; Warchol, Mark E; Palmiter, Richard D; Rubel, Edwin W

    2015-05-20

    During nervous system development, critical periods are usually defined as early periods during which manipulations dramatically change neuronal structure or function, whereas the same manipulations in mature animals have little or no effect on the same property. Neurons in the ventral cochlear nucleus (CN) are dependent on excitatory afferent input for survival during a critical period of development. Cochlear removal in young mammals and birds results in rapid death of target neurons in the CN. Cochlear removal in older animals results in little or no neuron death. However, the extent to which hair-cell-specific afferent activity prevents neuronal death in the neonatal brain is unknown. We further explore this phenomenon using a new mouse model that allows temporal control of cochlear hair cell deletion. Hair cells express the human diphtheria toxin (DT) receptor behind the Pou4f3 promoter. Injections of DT resulted in nearly complete loss of organ of Corti hair cells within 1 week of injection regardless of the age of injection. Injection of DT did not influence surrounding supporting cells directly in the sensory epithelium or spiral ganglion neurons (SGNs). Loss of hair cells in neonates resulted in rapid and profound neuronal loss in the ventral CN, but not when hair cells were eliminated at a more mature age. In addition, normal survival of SGNs was dependent on hair cell integrity early in development and less so in mature animals. This defines a previously undocumented critical period for SGN survival. Copyright © 2015 the authors 0270-6474/15/357878-14$15.00/0.

  10. External light activates hair follicle stem cells through eyes via an ipRGC-SCN-sympathetic neural pathway.

    Science.gov (United States)

    Fan, Sabrina Mai-Yi; Chang, Yi-Ting; Chen, Chih-Lung; Wang, Wei-Hung; Pan, Ming-Kai; Chen, Wen-Pin; Huang, Wen-Yen; Xu, Zijian; Huang, Hai-En; Chen, Ting; Plikus, Maksim V; Chen, Shih-Kuo; Lin, Sung-Jan

    2018-06-29

    Changes in external light patterns can alter cell activities in peripheral tissues through slow entrainment of the central clock in suprachiasmatic nucleus (SCN). It remains unclear whether cells in otherwise photo-insensitive tissues can achieve rapid responses to changes in external light. Here we show that light stimulation of animals' eyes results in rapid activation of hair follicle stem cells with prominent hair regeneration. Mechanistically, light signals are interpreted by M1-type intrinsically photosensitive retinal ganglion cells (ipRGCs), which signal to the SCN via melanopsin. Subsequently, efferent sympathetic nerves are immediately activated. Increased norepinephrine release in skin promotes hedgehog signaling to activate hair follicle stem cells. Thus, external light can directly regulate tissue stem cells via an ipRGC-SCN autonomic nervous system circuit. Since activation of sympathetic nerves is not limited to skin, this circuit can also facilitate rapid adaptive responses to external light in other homeostatic tissues.

  11. l-N-acetylcysteine protects outer hair cells against TNFα initiated ototoxicity in vitro.

    Science.gov (United States)

    Tillinger, Joshua A; Gupta, Chhavi; Ila, Kadri; Ahmed, Jamal; Mittal, Jeenu; Van De Water, Thomas R; Eshraghi, Adrien A

    2018-03-07

    The present study is aimed at determining the efficacy and exploring the mechanisms by which l-N-acetylcysteine (l-NAC) provides protection against tumor necrosis factor-alpha (TNFα)-induced oxidative stress damage and hair cell loss in 3-day-old rat organ of Corti (OC) explants. Previous work has demonstrated a high level of oxidative stress in TNFα-challenged OC explants. TNFα can potentially play a significant role in hair cell loss following an insult to the inner ear. l-NAC has shown to provide effective protection against noise-induced hearing loss in laboratory animals but mechanisms of this otoprotective effect are not well-defined. Rat OC explants were exposed to either: (1) saline control (N = 12); (2) TNFα (2 μg/ml, N = 12); (3) TNFα+l-NAC (5 mM, N = 12); (4) TNFα+l-NAC (10 mM, N = 12); or (5) l-NAC (10 mM, N = 12). Outer hair cell (OHC) density, levels of reactive oxygen species (ROS), lipid peroxidation of cell membranes, gluthathione activity, and mitochondrial viability were assayed. l-NAC (5 and 10 mM) provided protection for OHCs from ototoxic level of TNFα in OC explants. Groups treated with TNFα+l-NAC (5 mM) showed a highly significant reduction of both ROS (p l-NAC (5 mM) treated explants (p l-NAC is a promising treatment for protecting auditory HCs from TNFα-induced oxidative stress and subsequent loss via programmed cell death.

  12. Distinguishing diffuse alopecia areata (AA) from pattern hair loss (PHL) using CD3(+) T cells.

    Science.gov (United States)

    Kolivras, Athanassios; Thompson, Curtis

    2016-05-01

    Distinguishing between diffuse subacute alopecia areata (AA), in which the peribulbar infiltrate is absent, and pattern hair loss is challenging, particularly in cases that lack marked follicular miniaturization and a marked catagen/telogen shift. We sought to distinguish diffuse AA from pattern hair loss using CD3(+) T lymphocytes. A total of 28 cases of subacute AA and 31 cases of pattern hair loss were selected and a 4-mm punch biopsy was performed. All the specimens were processed using the "HoVert" (horizontal and vertical) technique. In all cases, hematoxylin-eosin and immunohistochemical stains for CD3, CD4, CD8, and CD20 were performed. The presence of CD3(+) lymphocytes within empty follicular fibrous tracts (stela), even without a concomitant peribulbar infiltrate, is a reliable histopathological clue in supporting a diagnosis of AA (sensitivity 0.964, specificity 1, P ≤ .001). Limited tissue for analysis remained in the clinical sample tissue blocks. The presence of CD3(+) T-cells within empty follicular fibrous tracts (stela) supports a diagnosis of AA. Copyright © 2015 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  13. Inner hair cell stereocilia movements captured in-situ by a high-speed camera with subpixel image processing

    Science.gov (United States)

    Wang, Yanli; Puria, Sunil; Steele, Charles R.; Ricci, Anthony J.

    2018-05-01

    Mechanical stimulation of the stereocilia hair bundles of the inner and outer hair cells (IHCs and OHCs, respectively) drives IHC synaptic release and OHC electromotility. The modes of hair-bundle motion can have a dramatic influence on the electrophysiological responses of the hair cells. The in vivo modes of motion are, however, unknown for both IHC and OHC bundles. In this work, we are developing technology to investigate the in situ hair-bundle motion in excised mouse cochleae, for which the hair bundles of the OHCs are embedded in the tectorial membrane but those of the IHCs are not. Motion is generated by pushing onto the stapes at 1 kHz with a glass probe coupled to a piezo stack, and recorded using a high-speed camera at 10,000 frames per second. The motions of individual IHC stereocilia and the cell boundary are analyzed using 2D and 1D Gaussian fitting algorithms, respectively. Preliminary results show that the IHC bundle moves mainly in the radial direction and exhibits a small degree of splay, and that the stereocilia in the second row move less than those in the first row, even in the same focal plane.

  14. Nuclear Mechanics and Stem Cell Differentiation.

    Science.gov (United States)

    Mao, Xinjian; Gavara, Nuria; Song, Guanbin

    2015-12-01

    Stem cells are characterized by their self-renewal and multi-lineage differentiation potential. Stem cell differentiation is a prerequisite for the application of stem cells in regenerative medicine and clinical therapy. In addition to chemical stimulation, mechanical cues play a significant role in regulating stem cell differentiation. The integrity of mechanical sensors is necessary for the ability of cells to respond to mechanical signals. The nucleus, the largest and stiffest cellular organelle, interacts with the cytoskeleton as a key mediator of cell mechanics. Nuclear mechanics are involved in the complicated interactions of lamins, chromatin and nucleoskeleton-related proteins. Thus, stem cell differentiation is intimately associated with nuclear mechanics due to its indispensable role in mechanotransduction and mechanical response. This paper reviews several main contributions of nuclear mechanics, highlights the hallmarks of the nuclear mechanics of stem cells, and provides insight into the relationship between nuclear mechanics and stem cell differentiation, which may guide clinical applications in the future.

  15. Local Mechanisms for Loud Sound-Enhanced Aminoglycoside Entry into Outer Hair Cells

    Directory of Open Access Journals (Sweden)

    Hongzhe eLi

    2015-04-01

    Full Text Available Loud sound exposure exacerbates aminoglycoside ototoxicity, increasing the risk of permanent hearing loss and degrading the quality of life in affected individuals. We previously reported that loud sound exposure induces temporary threshold shifts (TTS and enhances uptake of aminoglycosides, like gentamicin, by cochlear outer hair cells (OHCs. Here, we explore mechanisms by which loud sound exposure and TTS could increase aminoglycoside uptake by OHCs that may underlie this form of ototoxic synergy.Mice were exposed to loud sound levels to induce TTS, and received fluorescently-tagged gentamicin (GTTR for 30 minutes prior to fixation. The degree of TTS was assessed by comparing auditory brainstem responses before and after loud sound exposure. The number of tip links, which gate the GTTR-permeant mechanoelectrical transducer (MET channels, was determined in OHC bundles, with or without exposure to loud sound, using scanning electron microscopy.We found wide-band noise (WBN levels that induce TTS also enhance OHC uptake of GTTR compared to OHCs in control cochleae. In cochlear regions with TTS, the increase in OHC uptake of GTTR was significantly greater than in adjacent pillar cells. In control mice, we identified stereociliary tip links at ~50% of potential positions in OHC bundles. However, the number of OHC tip links was significantly reduced in mice that received WBN at levels capable of inducing TTS.These data suggest that GTTR uptake by OHCs during TTS occurs by increased permeation of surviving, mechanically-gated MET channels, and/or non-MET aminoglycoside-permeant channels activated following loud sound exposure. Loss of tip links would hyperpolarize hair cells and potentially increase drug uptake via aminoglycoside-permeant channels expressed by hair cells. The effect of TTS on aminoglycoside-permeant channel kinetics will shed new light on the mechanisms of loud sound-enhanced aminoglycoside uptake, and consequently on ototoxic

  16. Peroxynitrite induces apoptosis of mouse cochlear hair cells via a Caspase-independent pathway in vitro.

    Science.gov (United States)

    Cao, Zhixin; Yang, Qianqian; Yin, Haiyan; Qi, Qi; Li, Hongrui; Sun, Gaoying; Wang, Hongliang; Liu, Wenwen; Li, Jianfeng

    2017-11-01

    Peroxynitrite (ONOO - ) is a potent and versatile oxidant implicated in a number of pathophysiological processes. The present study was designed to investigate the effect of ONOO - on the cultured cochlear hair cells (HCs) of C57BL/6 mice in vitro as well as the possible mechanism underlying the action of such an oxidative stress. The in vitro primary cultured cochlear HCs were subjected to different concentrations of ONOO - , then, the cell survival and morphological changes were examined by immunofluorescence and transmission electron microscopy (TEM), the apoptosis was determined by Terminal deoxynucleotidyl transferase dUNT nick end labeling (TUNEL) assay, the mRNA expressions of Caspase-3, Caspase-8, Caspase-9, Apaf1, Bcl-2, and Bax were analyzed by RT-PCR, and the protein expressions of Caspase-3 and AIF were assessed by immunofluorescence. This work demonstrated that direct exposure of primary cultured cochlear HCs to ONOO - could result in a base-to-apex gradient injury of HCs in a concentration-dependent manner. Furthermore, ONOO - led to much more losses of outer hair cells than inner hair cells mainly through the induction of apoptosis of HCs as evidenced by TEM and TUNEL assays. The mRNA expressions of Caspase-8, Caspase-9, Apaf1, and Bax were increased and, meanwhile, the mRNA expression of Bcl-2 was decreased in response to ONOO - treatment. Of interesting, the expression of Caspase-3 had no significant change, whereas, the expression alteration of AIF was observed. These results suggested that ONOO - can effectively damage the survival of cochlear HCs via triggering the apoptotic pathway. The findings from this work suggest that ONOO - -induced apoptosis is mediated, at least in part, via a Caspase-independent pathway in cochlear HCs.

  17. Functional recovery of anterior semicircular canal afferents following hair cell regeneration in birds

    Science.gov (United States)

    Boyle, Richard; Highstein, Stephen M.; Carey, John P.; Xu, Jinping

    2002-01-01

    Streptomycin sulfate (1.2 g/kg i.m.) was administered for 5 consecutive days to 5-7-day-old white Leghorn chicks; this causes damage to semicircular canal hair cells that ultimately regenerate to reform the sensory epithelium. During the recovery period, electrophysiological recordings were taken sequentially from anterior semicircular canal primary afferents using an indentation stimulus of the canal that has been shown to mimic rotational stimulation. Chicks were assigned to an early (14-18 days; n = 8), intermediate (28-34 days; n = 5), and late (38-58 days; n = 4) period based on days after treatment. Seven untreated chicks, 15-67 days old, provided control data. An absence of background and indent-induced discharge was the prominent feature of afferents in the early period: only "silent" afferents were encountered in 5/8 experiments. In several of these chicks, fascicles of afferent fibers were seen extending up to the epithelium that was void of hair cells, and intra- and extracellular biocytin labeling revealed afferent processes penetrating into the supporting cell layer of the crista. In 3/8 chicks 74 afferents could be characterized, and they significantly differed from controls (n = 130) by having a lower discharge rate and a negligible response to canal stimulation. In the intermediate period there was considerable variability in discharge properties of 121 afferents, but as a whole the number of "silent" fibers in the canal nerve diminished, the background rate increased, and a response to canal stimulation detected. Individually biocytin-labeled afferents had normal-appearing terminal specializations in the sensory epithelium by 28 days poststreptomycin. In the late period, afferents (n = 58) remained significantly different from controls in background discharge properties and response gain. The evidence suggests that a considerable amount of variability exists between chicks in the return of vestibular afferent function following ototoxic injury and

  18. Effect of low-level laser treatment on cochlea hair-cell recovery after ototoxic hearing loss

    Science.gov (United States)

    Rhee, Chung-Ku; He, Peijie; Jung, Jae Yun; Ahn, Jin-Chul; Chung, Phil-Sang; Lee, Min Young; Suh, Myung-Whan

    2013-12-01

    The primary cause of hearing loss includes damage to cochlear hair cells. Low-level laser therapy (LLLT) has become a popular treatment for damaged nervous systems. Based on the idea that cochlea hair cells and neural cells are from same developmental origin, the effect of LLLT on hearing loss in animal models is evaluated. Hearing loss animal models were established, and the animals were irradiated by 830-nm diode laser once a day for 10 days. Power density of the laser treatment was 900 mW/cm2, and the fluence was 162 to 194 J. The tympanic membrane was evaluated after LLLT. Thresholds of auditory brainstem responses were evaluated before treatment, after gentamicin, and after 10 days of LLLT. Quantitative scanning electron microscopic (SEM) observations were done by counting remaining hair cells. Tympanic membranes were intact at the end of the experiment. No adverse tissue reaction was found. On SEM images, LLLT significantly increased the number of hair cells in middle and basal turns. Hearing was significantly improved by laser irradiation. After LLLT treatment, both the hearing threshold and hair-cell count significantly improved.

  19. Effect of N-Acetylcysteine in Protecting from Simultaneous Noise and Carbon Monoxide Induced Hair Cell Loss

    Directory of Open Access Journals (Sweden)

    Akram Pourbakht

    2011-06-01

    Full Text Available Background and Aim: N-acetylcysteine, a glutathione precursor and reactive oxygen species scavenger, is reported to be effective in reducing noise-induced hearing loss. Many workers in industry are exposed simultaneously to noise and chemical pollutants such as carbon monoxide. We investigated effectiveness of N-acetylcysteine in protecting the cochlea from simultaneous noise and carbon monoxide damages.Methods: Twelve rabbits were exposed simeltaneously to 100 dB sound pressure level of broad band noise and carbon monoxide 8 hours a day for 5 days. One hour before exposure, experimental group received 325 mg/kg of N-acetylcysteine while normal saline was administered for the control group. The protective effect of N-acetylcysteine was evaluated 3 weeks after exposure by histological assessment of the hair cells.Results: Simultaneous exposure to noise and carbon monoxide resulted in a considerable damage to the outer hair cells; however, the inner hair cells and the pillar cells remained intact. Use of N-acetylcysteine in the experimental group significantly reduced the extent of outer hair cell loss.Conclusion: N-acetylcysteine attenuates simultaneous noise and carbon monoxide induced hair cell damage in rabbits.

  20. Rescue of Outer Hair Cells with Antisense Oligonucleotides in Usher Mice Is Dependent on Age of Treatment.

    Science.gov (United States)

    Ponnath, Abhilash; Depreux, Frederic F; Jodelka, Francine M; Rigo, Frank; Farris, Hamilton E; Hastings, Michelle L; Lentz, Jennifer J

    2018-02-01

    The absence of functional outer hair cells is a component of several forms of hereditary hearing impairment, including Usher syndrome, the most common cause of concurrent hearing and vision loss. Antisense oligonucleotide (ASO) treatment of mice with the human Usher mutation, Ush1c c.216G>A, corrects gene expression and significantly improves hearing, as measured by auditory-evoked brainstem responses (ABRs), as well as inner and outer hair cell (IHC and OHC) bundle morphology. However, it is not clear whether the improvement in hearing achieved by ASO treatment involves the functional rescue of outer hair cells. Here, we show that Ush1c c.216AA mice lack OHC function as evidenced by the absence of distortion product otoacoustic emissions (DPOAEs) in response to low-, mid-, and high-frequency tone pairs. This OHC deficit is rescued by treatment with an ASO that corrects expression of Ush1c c.216G>A. Interestingly, although rescue of inner hairs cells, as measured by ABR, is achieved by ASO treatment as late as 7 days after birth, rescue of outer hair cells, measured by DPOAE, requires treatment before post-natal day 5. These results suggest that ASO-mediated rescue of both IHC and OHC function is age dependent and that the treatment window is different for the different cell types. The timing of treatment for congenital hearing disorders is of critical importance for the development of drugs such ASO-29 for hearing rescue.

  1. Titrated extract of Centella asiatica increases hair inductive property through inhibition of STAT signaling pathway in three-dimensional spheroid cultured human dermal papilla cells.

    Science.gov (United States)

    Choi, Yeong Min; An, Sungkwan; Lee, Junwoo; Lee, Jae Ho; Lee, Jae Nam; Kim, Young Sam; Ahn, Kyu Joong; An, In-Sook; Bae, Seunghee

    2017-12-01

    Dermal papilla (DP) is a pivotal part of hair follicle, and the smaller size of the DP is related with the hair loss. In this study, we investigated the effect of titrated extract of Centella asiatica (TECA) on hair growth inductive property on 3D spheroid cultured human DP cells (HDP cells). Significantly increased effect of TECA on cell viability was only shown in 3D sphered HPD cells, not in 2D cultured HDP cells. Also, TECA treatment increased the sphere size of HDP cells. The luciferase activity of STAT reporter genes and the expression of STAT-targeted genes, SOCS1 and SOCS3, were significantly decreased. Also, TECA treatment increased the expression of the hair growth-related signature genes in 3D sphered HDP cells. Furthermore, TECA led to downregulation of the level of phosphorylated STAT proteins in 3D sphered HDP cells. Overall, TECA activates the potential of hair inductive capacity in HDP cells.

  2. Partial Aminoglycoside Lesions in Vestibular Epithelia Reveal Broad Sensory Dysfunction Associated with Modest Hair Cell Loss and Afferent Calyx Retraction.

    Science.gov (United States)

    Sultemeier, David R; Hoffman, Larry F

    2017-01-01

    Although the effects of aminoglycoside antibiotics on hair cells have been investigated for decades, their influences on the dendrites of primary afferent neurons have not been widely studied. This is undoubtedly due to the difficulty in disassociating pathology to dendritic processes from that resulting from loss of the presynaptic hair cell. This was overcome in the present investigation through development of a preparation using Chinchilla laniger that enabled direct perilymphatic infusion. Through this strategy we unmasked gentamicin's potential effects on afferent calyces. The pathophysiology of the vestibular neuroepithelia after post-administration durations of 0.5 through 6 months was assessed using single-neuron electrophysiology, immunohistochemistry, and confocal microscopy. Hair cell densities within cristae central zones (0.5-, 1-, 2-, and 6-months) and utricle peri- and extrastriola (6-months) regions were determined, and damage to calretinin-immunoreactive calyces was quantified. Gentamicin-induced hair cell loss exhibited a profile that reflected elimination of a most-sensitive group by 0.5-months post-administration (18.2%), followed by loss of a second group (20.6%) over the subsequent 5.5 months. The total hair cell loss with this gentamicin dose (approximately 38.8%) was less than the estimated fraction of type I hair cells in the chinchilla's crista central zone (approximately 60%), indicating that viable type I hair cells remained. Extensive lesions to afferent calyces were observed at 0.5-months, though stimulus-evoked modulation was intact at this post-administration time. Widespread compromise to calyx morphology and severe attenuation of stimulus-evoked afferent discharge modulation was found at 1 month post-administration, a condition that persisted in preparations examined through the 6-month post-administration interval. Spontaneous discharge was robust at all post-administration intervals. All calretinin-positive calyces had retracted

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

    Science.gov (United States)

    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.

  4. The mechanosensory structure of the hair cell requires clarin-1, a protein encoded by Usher syndrome III causative gene.

    Science.gov (United States)

    Geng, Ruishuang; Melki, Sami; Chen, Daniel H-C; Tian, Guilian; Furness, David N; Oshima-Takago, Tomoko; Neef, Jakob; Moser, Tobias; Askew, Charles; Horwitz, Geoff; Holt, Jeffrey R; Imanishi, Yoshikazu; Alagramam, Kumar N

    2012-07-11

    Mutation in the clarin-1 gene (Clrn1) results in loss of hearing and vision in humans (Usher syndrome III), but the role of clarin-1 in the sensory hair cells is unknown. Clarin-1 is predicted to be a four transmembrane domain protein similar to members of the tetraspanin family. Mice carrying null mutation in the clarin-1 gene (Clrn1(-/-)) show loss of hair cell function and a possible defect in ribbon synapse. We investigated the role of clarin-1 using various in vitro and in vivo approaches. We show by immunohistochemistry and patch-clamp recordings of Ca(2+) currents and membrane capacitance from inner hair cells that clarin-1 is not essential for formation or function of ribbon synapse. However, reduced cochlear microphonic potentials, FM1-43 [N-(3-triethylammoniumpropyl)-4-(4-(dibutylamino)styryl) pyridinium dibromide] loading, and transduction currents pointed to diminished cochlear hair bundle function in Clrn1(-/-) mice. Electron microscopy of cochlear hair cells revealed loss of some tall stereocilia and gaps in the v-shaped bundle, although tip links and staircase arrangement of stereocilia were not primarily affected by Clrn1(-/-) mutation. Human clarin-1 protein expressed in transfected mouse cochlear hair cells localized to the bundle; however, the pathogenic variant p.N48K failed to localize to the bundle. The mouse model generated to study the in vivo consequence of p.N48K in clarin-1 (Clrn1(N48K)) supports our in vitro and Clrn1(-/-) mouse data and the conclusion that CLRN1 is an essential hair bundle protein. Furthermore, the ear phenotype in the Clrn1(N48K) mouse suggests that it is a valuable model for ear disease in CLRN1(N48K), the most prevalent Usher syndrome III mutation in North America.

  5. Association of intracellular and synaptic organization in cochlear inner hair cells revealed by 3D electron microscopy

    OpenAIRE

    Bullen, Anwen; West, Timothy; Moores, Carolyn; Ashmore, Jonathan; Fleck, Roland A.; MacLellan-Gibson, Kirsty; Forge, Andrew

    2015-01-01

    ABSTRACT The ways in which cell architecture is modelled to meet cell function is a poorly understood facet of cell biology. To address this question, we have studied the cytoarchitecture of a cell with highly specialised organisation, the cochlear inner hair cell (IHC), using multiple hierarchies of three-dimensional (3D) electron microscopy analyses. We show that synaptic terminal distribution on the IHC surface correlates with cell shape, and the distribution of a highly organised network ...

  6. Influence of leisure-time noise on outer hair cell activity in medical students.

    Science.gov (United States)

    Rosanowski, Frank; Eysholdt, Ulrich; Hoppe, Ulrich

    2006-10-01

    Noise exceeding a certain level can damage outer hair cells and thus cause hearing loss. In the past, noise-induced hearing loss was mainly caused by occupational noise. Leisure-time noise may be a promoting factor, particularly in young adults. The purpose of this study was to investigate whether transient evoked otoacoustic emissions (TEOAE) can be used to evaluate outer hair cell damage in young adults with no history of hearing complaints. The data obtained from the measurement of TEOAE were correlated with the participants' listening habits and exposure to leisure-time noise. Eighty-eight young adults (47 women, 41 men; age 22.9+/-2.9 years) were examined. TEOAE were measured using standard ILO 88 equipment. All participants had normal hearing (hearing thresholds better than 20 dB HL; frequency range 0.125-10 kHz). None of the participants suffered from permanent tinnitus. All participants answered a questionnaire concerning their listening habits. On average, the participants frequented a discotheque 1.4 times a month; 25% had never visited a discotheque, 35% visited once a month and 32% twice or three times a month. Sixteen per cent reported transient tinnitus after every visit to a discotheque and 58% after nearly every visit. Eight per cent suffered from transient hearing loss after every visit to a disco and 37% after nearly every visit. Three per cent (4%) reported tinnitus (nearly) every morning after visiting a discotheque. The TEOAE level was above 6 dB in all participants [9.2+/-3.6 dB (mean +/- SD)] and reproducibility was above 60% (90+/-9%). All values matched pass criteria for normal TEOAE under clinical conditions. However, TEOAE levels and reproducibility decreased significantly with an increased number of visits to discotheques. Outer hair cell damage could be measured using TEOAE in individuals exposed to leisure-time noise, although these individuals exhibited no measurable puretone hearing loss.

  7. Can bone marrow differentiate into renal cells?

    Science.gov (United States)

    Imai, Enyu; Ito, Takahito

    2002-10-01

    A considerable plasticity of adult stem cells has been confirmed in a wide variety of tissues. In particular, the pluripotency of bone marrow-derived stem cells may influence the regeneration of injured tissues and may provide novel avenues in regenerative medicine. Bone marrow contains at least hematopoietic and mesenchymal stem cells, and both can differentiate into a wide range of differentiated cells. Side population (SP) cells, which are originally defined in bone marrow cells by high efflux of DNA-binding dye, seem to be a new class of multipotent stem cells. Irrespective of the approach used to obtain stem cells, the fates of marrow-derived cells following bone marrow transplantation can be traced by labeling donor cells with green fluorescence protein or by identifying donor Y chromosome in female recipients. So far, bone marrow-derived cells have been reported to differentiate into renal cells, including mesangial cells, endothelial cells, podocytes, and tubular cells in the kidney, although controversy exists. Further studies are required to address this issue. Cell therapy will be promising when we learn to control stem cells such as bone marrow-derived stem cells, embryonic stem cells, and resident stem cells in the kidney. Identification of factors that support stem cells or promote their differentiation should provide a relevant step towards cell therapy.

  8. Future time perspective: opportunities and limitations are differentially associated with subjective well-being and hair cortisol concentration.

    Science.gov (United States)

    Kozik, Pavel; Hoppmann, Christiane A; Gerstorf, Denis

    2015-01-01

    Future time perspective has been associated with subjective well-being, though depending on the line of research considered either an open-ended future time perspective or a limited future time perspective has been associated with high well-being. Most of this research however has conceptualized future time perspective as a one-dimensional construct, whereas recent evidence has demonstrated that there are likely at least two different underlying dimensions, a focus on opportunities and a focus on limitations. This project first seeks to replicate the two-dimensional structure of the Future Time Perspective Scale, and then examines the associations these dimensions may have with different measures of subjective well-being and a biological index of chronic stress. To test if the two dimensions of the Future Time Perspective Scale, a focus on opportunities and a focus on limitations, differentially associate with two measures of subjective well-being and a biological indicator of chronic stress, namely hair cortisol. Sixty-six community-dwelling participants with a mean age of 72 years (SD = 5.83) completed the Future Time Perspective Scale, Center for Epidemiologic Studies Depression Scale, and Philadelphia Geriatric Center Morale Scale. Participants also provided a 3-cm-long hair strand to index cortisol accumulation over the past 3 months. Following the results of a factor analysis, a mediation model was created for each dimension of the Future Time Perspective Scale, and significance testing was done through a bootstrapping approach to harness maximal statistical power. Factor analysis results replicated the two-dimensional structure of the Future Time Perspective Scale. Both dimensions were then found to have unique associations with well-being. Specifically, a high focus on opportunities was associated with fewer depressive symptoms and higher morale, whereas a low focus on limitations was associated with reduced hair cortisol, though this association was

  9. ATP-gamma-S shifts the operating point of outer hair cell transduction towards scala tympani.

    Science.gov (United States)

    Bobbin, Richard P; Salt, Alec N

    2005-07-01

    ATP receptor agonists and antagonists alter cochlear mechanics as measured by changes in distortion product otoacoustic emissions (DPOAE). Some of the effects on DPOAEs are consistent with the hypothesis that ATP affects mechano-electrical transduction and the operating point of the outer hair cells (OHCs). This hypothesis was tested by monitoring the effect of ATP-gamma-S on the operating point of the OHCs. Guinea pigs anesthetized with urethane and with sectioned middle ear muscles were used. The cochlear microphonic (CM) was recorded differentially (scala vestibuli referenced to scala tympani) across the basal turn before and after perfusion (20 min) of the perilymph compartment with artificial perilymph (AP) and ATP-gamma-S dissolved in AP. The operating point was derived from the cochlear microphonics (CM) recorded in response low frequency (200 Hz) tones at high level (106, 112 and 118 dB SPL). The analysis procedure used a Boltzmann function to simulate the CM waveform and the Boltzmann parameters were adjusted to best-fit the calculated waveform to the CM. Compared to the initial perfusion with AP, ATP-gamma-S (333 microM) enhanced peak clipping of the positive peak of the CM (that occurs during organ of Corti displacements towards scala tympani), which was in keeping with ATP-induced displacement of the transducer towards scala tympani. CM waveform analysis quantified the degree of displacement and showed that the changes were consistent with the stimulus being centered on a different region of the transducer curve. The change of operating point meant that the stimulus was applied to a region of the transducer curve where there was greater saturation of the output on excursions towards scala tympani and less saturation towards scala vestibuli. A significant degree of recovery of the operating point was observed after washing with AP. Dose response curves generated by perfusing ATP-gamma-S (333 microM) in a cumulative manner yielded an EC(50) of 19.8 micro

  10. Confirming a Role for α9nAChRs and SK Potassium Channels in Type II Hair Cells of the Turtle Posterior Crista

    Directory of Open Access Journals (Sweden)

    Xiaorong Xu Parks

    2017-11-01

    Full Text Available In turtle posterior cristae, cholinergic vestibular efferent neurons (VENs synapse on type II hair cells, bouton afferents innervating type II hair cells, and afferent calyces innervating type I hair cells. Electrical stimulation of VENs releases acetylcholine (ACh at these synapses to exert diverse effects on afferent background discharge including rapid inhibition of bouton afferents and excitation of calyx-bearing afferents. Efferent-mediated inhibition is most pronounced in bouton afferents innervating type II hair cells near the torus, but becomes progressively smaller and briefer when moving longitudinally through the crista toward afferents innervating the planum. Sharp-electrode recordings have inferred that efferent-mediated inhibition of bouton afferents requires the sequential activation of alpha9-containing nicotinic ACh receptors (α9*nAChRs and small-conductance, calcium-dependent potassium channels (SK in type II hair cells. Gradations in the strength of efferent-mediated inhibition across the crista likely reflect variations in α9*nAChRs and/or SK activation in type II hair cells from those different regions. However, in turtle cristae, neither inference has been confirmed with direct recordings from type II hair cells. To address these gaps, we performed whole-cell, patch-clamp recordings from type II hair cells within a split-epithelial preparation of the turtle posterior crista. Here, we can easily visualize and record hair cells while maintaining their native location within the neuroepithelium. Consistent with α9*nAChR/SK activation, ACh-sensitive currents in type II hair cells were inward at hyperpolarizing potentials but reversed near −90 mV to produce outward currents that typically peaked around −20 mV. ACh-sensitive currents were largest in torus hair cells but absent from hair cells near the planum. In current clamp recordings under zero-current conditions, ACh robustly hyperpolarized type II hair cells. ACh

  11. In Vivo Interplay between p27Kip1, GATA3, ATOH1, and POU4F3 Converts Non-sensory Cells to Hair Cells in Adult Mice

    Directory of Open Access Journals (Sweden)

    Bradley J. Walters

    2017-04-01

    Full Text Available Summary: Hearing loss is widespread and persistent because mature mammalian auditory hair cells (HCs are nonregenerative. In mice, the ability to regenerate HCs from surrounding supporting cells (SCs declines abruptly after postnatal maturation. We find that combining p27Kip1 deletion with ectopic ATOH1 expression surmounts this age-related decline, leading to conversion of SCs to HCs in mature mouse cochleae and after noise damage. p27Kip1 deletion, independent of canonical effects on Rb-family proteins, upregulated GATA3, a co-factor for ATOH1 that is lost from SCs with age. Co-activation of GATA3 or POU4F3 and ATOH1 promoted conversion of SCs to HCs in adult mice. Activation of POU4F3 alone also converted mature SCs to HCs in vivo. These data illuminate a genetic pathway that initiates auditory HC regeneration and suggest p27Kip1, GATA3, and POU4F3 as additional therapeutic targets for ATOH1-mediated HC regeneration. : Auditory hair cells are nonregenerative, resulting in persistent hearing loss upon damage. Walters et al. find that manipulating two genes, p27Kip1 and Atoh1, induces the conversion of nonsensory cells to hair cells in adult mice. This effect is mediated by GATA3 and POU4F3, where POU4F3 alone was found to convert nonsensory cells. Keywords: regeneration, aging, differentiation, proliferation, development, cancer, sensory, cochlea, hearing

  12. Hair Loss

    Science.gov (United States)

    ... is why some people with eating disorders like anorexia and bulimia lose their hair: The body isn't getting enough protein, vitamins, and minerals to support hair growth. Some teens who are vegetarians also lose their hair if ...

  13. S-nitrosoglutathione promotes cell wall remodelling, alters the transcriptional profile and induces root hair formation in the hairless root hair defective 6 (rhd6) mutant of Arabidopsis thaliana.

    Science.gov (United States)

    Moro, Camila Fernandes; Gaspar, Marilia; da Silva, Felipe Rodrigues; Pattathil, Sivakumar; Hahn, Michael G; Salgado, Ione; Braga, Marcia Regina

    2017-03-01

    Nitric oxide (NO) exerts pleiotropic effects on plant development; however, its involvement in cell wall modification during root hair formation (RHF) has not yet been addressed. Here, mutants of Arabidopsis thaliana with altered root hair phenotypes were used to assess the involvement of S-nitrosoglutathione (GSNO), the primary NO source, in cell wall dynamics and gene expression in roots induced to form hairs. GSNO and auxin restored the root hair phenotype of the hairless root hair defective 6 (rhd6) mutant. A positive correlation was observed between increased NO production and RHF induced by auxin in rhd6 and transparent testa glabra (ttg) mutants. Deposition of an epitope within rhamnogalacturonan-I recognized by the CCRC-M2 antibody was delayed in root hair cells (trichoblasts) compared with nonhair cells (atrichoblasts). GSNO, but not auxin, restored the wild-type root glycome and transcriptome profiles in rhd6, modulating the expression of a large number of genes related to cell wall composition and metabolism, as well as those encoding ribosomal proteins, DNA and histone-modifying enzymes and proteins involved in post-translational modification. Our results demonstrate that NO plays a key role in cell wall remodelling in trichoblasts and suggest that it also participates in chromatin modification in root cells of A. thaliana. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  14. Cholesterol influences voltage-gated calcium channels and BK-type potassium channels in auditory hair cells.

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    Erin K Purcell

    Full Text Available The influence of membrane cholesterol content on a variety of ion channel conductances in numerous cell models has been shown, but studies exploring its role in auditory hair cell physiology are scarce. Recent evidence shows that cholesterol depletion affects outer hair cell electromotility and the voltage-gated potassium currents underlying tall hair cell development, but the effects of cholesterol on the major ionic currents governing auditory hair cell excitability are unknown. We investigated the effects of a cholesterol-depleting agent (methyl beta cyclodextrin, MβCD on ion channels necessary for the early stages of sound processing. Large-conductance BK-type potassium channels underlie temporal processing and open in a voltage- and calcium-dependent manner. Voltage-gated calcium channels (VGCCs are responsible for calcium-dependent exocytosis and synaptic transmission to the auditory nerve. Our results demonstrate that cholesterol depletion reduced peak steady-state calcium-sensitive (BK-type potassium current by 50% in chick cochlear hair cells. In contrast, MβCD treatment increased peak inward calcium current (~30%, ruling out loss of calcium channel expression or function as a cause of reduced calcium-sensitive outward current. Changes in maximal conductance indicated a direct impact of cholesterol on channel number or unitary conductance. Immunoblotting following sucrose-gradient ultracentrifugation revealed BK expression in cholesterol-enriched microdomains. Both direct impacts of cholesterol on channel biophysics, as well as channel localization in the membrane, may contribute to the influence of cholesterol on hair cell physiology. Our results reveal a new role for cholesterol in the regulation of auditory calcium and calcium-activated potassium channels and add to the growing evidence that cholesterol is a key determinant in auditory physiology.

  15. Hair Dye and Hair Relaxers

    Science.gov (United States)

    ... For Consumers Consumer Information by Audience For Women Hair Dye and Hair Relaxers Share Tweet Linkedin Pin it More sharing ... products. If you have a bad reaction to hair dyes and relaxers, you should: Stop using the ...

  16. Artificial Cochlear Sensory Epithelium with Functions of Outer Hair Cells Mimicked Using Feedback Electrical Stimuli

    Directory of Open Access Journals (Sweden)

    Tetsuro Tsuji

    2018-05-01

    Full Text Available We report a novel vibration control technique of an artificial auditory cochlear epithelium that mimics the function of outer hair cells in the organ of Corti. The proposed piezoelectric and trapezoidal membrane not only has the acoustic/electric conversion and frequency selectivity of the previous device developed mainly by one of the authors and colleagues, but also has a function to control local vibration according to sound stimuli. Vibration control is achieved by applying local electrical stimuli to patterned electrodes on an epithelium made using micro-electro-mechanical system technology. By choosing appropriate phase differences between sound and electrical stimuli, it is shown that it is possible to both amplify and dampen membrane vibration, realizing better control of the response of the artificial cochlea. To be more specific, amplification and damping are achieved when the phase difference between the membrane vibration by sound stimuli and electrical stimuli is zero and π , respectively. We also demonstrate that the developed control system responds automatically to a change in sound frequency. The proposed technique can be applied to mimic the nonlinear response of the outer hair cells in a cochlea, and to realize a high-quality human auditory system.

  17. Fabrication and characterization of artificial hair cell sensor based on MWCNT-PDMS composite

    Science.gov (United States)

    Kim, Chi Yeon; Lee, Hyun Sup; Cho, Yo Han; Joh, Cheeyoung; Choi, Pyung; Park, Seong Jin

    2011-06-01

    The aim of this work is to design and fabricate a flow sensor using an artificial hair cell (AHC) inspired by biological hair cells of fish. The sensor consists of a single cilium structure with high aspect ratio and a mechanoreceptor using force sensitive resistor (FSR). The cilium structure is designed for capturing a drag force with direction due to flow field around the sensor and the mechanoreceptor is designed for sensing the drag force with direction from the cilium structure and converting it into an electric signal. The mechanoreceptor has a symmetric four electrodes to sense the drag force and its direction. To fabricate the single cilium structure with high aspect ratio, we have proposed a new design concept using a separated micro mold system (SMS) fabricated by the LIGA process. For a successful replication of the cilium structure, we used the hot embossing process with the help of a double-sided mold system. We used a composite of multiwall carbon nanotube and polydimethylsiloxane (MWCNT-PDMS). The performance of the mechanoreceptors was measured by a computer-controlled nanoindenter. We carried out several experiments with the sensor in the different flow rate and direction using the experimental test apparatus. To calibrate the sensor and calculate the velocity with direction based the signal from the sensor, we analyzed the coupled phenomena between flow field and the cilium structure to calculate the deflection of the cilium structure and the drag force applying to the cilium structure due to the flow field around sensor.

  18. ILDR1 deficiency causes degeneration of cochlear outer hair cells and disrupts the structure of the organ of Corti: a mouse model for human DFNB42

    Directory of Open Access Journals (Sweden)

    Qing Sang

    2015-03-01

    Full Text Available Immunoglobulin-like domain containing receptor 1 (ILDR1 is a poorly characterized gene that was first identified in lymphoma cells. Mutations in ILDR1 are responsible for DFNB42, but the pathogenesis of hearing loss caused by ILDR1 mutations remains to be elucidated. To explore the role of ILDR1 in hearing, we created Ildr1 knockout mice. In heterozygous mice, ILDR1 expression was found in outer hair cells (OHCs and inner hair cells (IHCs of the organ of Corti. ILDR1-deficient mice are profoundly deaf by postnatal day 21 (P21. No significant difference was observed in the supporting cells and IHCs of ILDR1-deficient mice, but progressive degeneration of OHCs occurred at P15 and disruption of the tunnel running through the organ of Corti was noticeable at P21. By P28, there were no OHCs visible in any of the turns of the organ of Corti, and the tunnel of the organ of Corti was entirely destroyed. ILDR1 deficiency affects expression of tricellulin in vivo, and this provides a possible explanation to hearing loss. To further elucidate the mechanism of deafness related to ILDR1 deficiency, we pursued a differential proteomic approach to comprehensively assess differential protein expression in the cochleae of Ildr1+/− and Ildr1−/− mice at P21. Altogether, 708 proteins were up-regulated (fold change >1.5 and 114 proteins were down-regulated (fold change <0.5 in the Ildr1−/− mice compared with Ildr1+/− mice. Gene ontology classification indicated that a number of differentially expressed proteins are involved in cell adhesion, protein and vesicle-mediated transport, cell death, membrane organization, and cellular homeostasis. A few of these proteins are closely related to hearing development. Taken together, our data suggest that ILDR1 is important for the survival of OHCs and provide novel insights into the pathogenesis of human deafness DFNB42 deafness.

  19. Transcriptome changes during intestinal cell differentiation

    DEFF Research Database (Denmark)

    Tadjali, Mehrdad; Seidelin, Jakob B; Olsen, Jørgen Lillelund

    2002-01-01

    The expression of 18149 genes have been analysed during the differentiation of the human intestinal cell line Caco-2. cDNA probes from undifferentiated and differentiated Caco-2 cells were separately hybridised to EST DNAs spotted in an array on a nylon membrane. A remarkable change in the transc...

  20. Expression of EFR3A in the mouse cochlea during degeneration of spiral ganglion following hair cell loss.

    Directory of Open Access Journals (Sweden)

    Chen Nie

    Full Text Available Retrograde degeneration of spiral ganglion cells in the cochlea following hair cell loss is similar to dying back in pathology. The EFR3A gene has recently been discovered to be involved in the pathogenesis of dying back. The relationship of EFR3A and spiral ganglion degeneration, however, was rarely investigated. In this study, we destroyed the hair cells of the mouse cochlea by co-administration of kanamycin and furosemide and then investigated the EFR3A expression during the induced spiral ganglion cell degeneration. Our results revealed that co-administration of kanamycin and furosemide quickly induced hair cell loss in the C57BL/6J mice and then resulted in progressive degeneration of the spiral ganglion beginning at day 5 following drug administration. The number of the spiral ganglion cells began to decrease at day 15. The expression of EFR3A increased remarkably in the spiral ganglion at day 5 and then decreased to near normal level within the next 10 days. Our study suggested that the change of EFR3A expression in the spiral ganglion was coincident with the time of the spiral ganglion degeneration, which implied that high expression of EFR3A may be important to prompt initiation of spiral ganglion degeneration following hair cell loss.

  1. Morphogenetic Mechanisms in the Cyclic Regeneration of Hair Follicles and Deer Antlers from Stem Cells

    Science.gov (United States)

    Li, Chunyi; McMahon, Chris

    2013-01-01

    We have made comparisons between hair follicles (HFs) and antler units (AUs)—two seemingly unrelated mammalian organs. HFs are tiny and concealed within skin, whereas AUs are gigantic and grown externally for visual display. However, these two organs share some striking similarities. Both consist of permanent and cyclic/temporary components and undergo stem-cell-based organogenesis and cyclic regeneration. Stem cells of both organs reside in the permanent part and the growth centres are located in the temporary part of each respective organ. Organogenesis and regeneration of both organs depend on epithelial-mesenchymal interactions. Establishment of these interactions requires stem cells and reactive/niche cells (dermal papilla cells for HFs and epidermal cells for AUs) to be juxtaposed, which is achieved through destruction of the cyclic part to bring the reactive cells into close proximity to the respective stem cell niche. Developments of HFs and AUs are regulated by similar endocrine (particularly testosterone) and paracrine (particularly IGF1) factors. Interestingly, these two organs come to interplay during antlerogenesis. In conclusion, we believe that investigators from the fields of both HF and AU biology could greatly benefit from a comprehensive comparison between these two organs. PMID:24383056

  2. The Mechanosensory Structure of the Hair Cell Requires Clarin-1, a Protein Encoded by Usher Syndrome III Causative Gene

    Science.gov (United States)

    Geng, Ruishuang; Melki, Sami; Chen, Daniel H.-C.; Tian, Guilian; Furness, David; Oshima-Takago, Tomoko; Neef, Jakob; Moser, Tobias; Askew, Charles; Horwitz, Geoff; Holt, Jeffrey; Imanishi, Yoshikazu; Alagramam, Kumar N.

    2012-01-01

    Mutation in the clarin-1 gene results in loss of hearing and vision in humans (Usher syndrome III), but the role of clarin-1 in the sensory hair cells is unknown. Clarin-1 is predicted to be a four transmembrane domain protein similar to members of the tetraspanin family. Mice carrying null mutation in the clarin-1 (Clrn1−/−) gene show loss of hair cell function and a possible defect in ribbon synapse. We investigated the role of clarin-1 using various in vitro and in vivo approaches. We show by immunohistochemistry and patch-clamp recordings of Ca2+ currents and membrane capacitance from IHCs that clarin-1 is not essential for formation or function of ribbon synapse. However, reduced cochlear microphonic potentials, FM1-43 loading and transduction currents pointed to diminished cochlear hair bundle function in Clrn1−/− mice. Electron microscopy of cochlear hair cells revealed loss of some tall stereocilia and gaps in the v-shaped bundle, although tip-links and staircase arrangement of stereocilia were not primarily affected by Clrn1−/− mutation. Human clarin-1 protein expressed in transfected mouse cochlear hair cells localized to the bundle; however, the pathogenic variant, p.N48K, failed to localize to the bundle. The mouse model generated to study the in vivo consequence of p. N48K in clarin-1 (Clrn1N48K) supports our in vitro and Clrn1−/− mouse data and the conclusion that CLRN1 is an essential hair bundle protein. Further, the ear phenotype in the Clrn1N48K mouse suggests that it is a valuable model for ear disease in CLRN1N48K, the most prevalent Usher III mutation in North America. PMID:22787034

  3. Management of hair loss diseases

    Directory of Open Access Journals (Sweden)

    Manabu Ohyama

    2010-12-01

    Full Text Available The treatment of hair loss diseases is sometimes difficult because of insufficient efficacy and limited options. However, recent advances in understanding of the pathophysiology and development of new remedies have improved the treatment of refractory hair loss conditions. In this article, an update on the management of hair loss diseases is provided, especially focusing on recently reported therapeutic approaches for alopecia areata (AA. An accurate diagnosis is indispensable to optimize treatment. Dry dermoscopy represents new diagnostic techniques, which could enable the differentiation of barely indistinguishable alopecias, e.g. AA and trichotillomania. An organized scalp biopsy adopting both vertical and transverse sectioning approaches also provides a deep insight into the pathophysiology of ongoing alopecias. Among various treatments for AA, intraregional corticosteroid and contact immunotherapy have been recognized as first-line therapies. However, some AA cases are refractory to both treatments. Recent studies have demonstrated the efficacy of pulse corticosteroid therapy or the combination of oral psoralen ultraviolet A therapy and systemic corticosteroids for severe AA. Previous clinical observations have suggested the potential role of antihistamines as supportive medications for AA. Experimental evaluation using AA model mice further supports their effectiveness in AA treatment. Finasteride opens up new possibilities for the treatment of androgenetic alopecia. For androgenetic alopecia patients refractory to finasteride, the combination of finasteride with topical minoxidil or the administration of dutasteride, another 5 alpha-reductase inhibitor, may provide better outcomes. Scarring alopecia is the most difficult form of hair loss disorder to treat. The bulge stem cell area is destroyed by unnecessary immune reactions with resultant permanent loss of hair follicle structures in scarring alopecia. Currently, treatment options for

  4. Hair biology and its comprehensive sequence in female pattern baldness: clinical connotation diagnosis and differential diagnosis--Part II.

    Science.gov (United States)

    Sehgal, Virendra N; Srivastava, Govind; Aggarwal, Ashok K; Midha, Rashmi

    2013-01-01

    Hair can become a source of concern when there is a change in its texture, number, and thinning. Although female pattern baldness is common, it has received little attention compared with male pattern baldness. Thinning that affects the vertex is insidious and progressive. Hair loss in women has accordingly been interpreted and classified differently than that in men. The Ludwig scale is the most accepted classification. The gross anatomy and the general microanatomy of the hair follicle, including that of the anagen, catagen, and telogen phase, are presented. The hair growth cycle, encompassing anagen, catagen, telogen, exogen, and kenogen, is also discussed to address pattern hair loss in women and provide therapeutic options that are currently available.

  5. Gene Expression in Hair Follicle Dermal Papilla Cells after Treatment with Stanozolol

    Directory of Open Access Journals (Sweden)

    M. Reiter

    2009-01-01

    Full Text Available Doping with anabolic agents is a topic in sports where strength is crucial, e.g. sprinting, weight lifting and many more. Testosterone and its functional analogs are the drugs of choice taken as pills, creams, tape or injections to increase muscle mass and body performance, and to reduce body fat. Stanozolol (17β-hydroxy-17α-methyl-5α-androst- 2-eno[3,2c]pyrazol is a testosterone analogue with the same anabolic effect like testosterone but its ring structure makes it possible to take it orally. Therefore, stanozolol is one of the most frequently used anabolic steroids. Common verification methods for anabolic drugs exist, identifying the chemicals in tissues, like hair or blood samples. The idea of this feasibility study was to search for specific gene expression regulations induced by stanozolol to identify the possible influence of the synthetically hormone on different metabolic pathways. Finding biomarkers for anabolic drugs could be supportive of the existing methods and an additional proof for illegal drug abuse. In two separate cell cultures, human HFDPC (hair follicle dermal papilla cells from a female and a male donor were treated with stanozolol. In the female cell culture treatment concentrations of 0 nM (control, 1 nM, 10 nM and 100 nM were chosen. Cells were taken 0 h, 6 h, 24 h and 48 h after stimulation and totalRNA was extracted. Learning from the results of the pilot experiment, the male cell culture was treated in 10 nM and 100 nM concentrations and taken after 0 h, 6 h, 24 h and 72 h. Using quantitative real-time RT-PCR expression of characteristics of different target genes were analysed. Totally 13 genes were selected according to their functionality by screening the actual literature and composed to functional groups: factors of apoptosis regulation were Fas Ligand (FasL, its receptor (FasR, Caspase 8 and Bcl-2. Androgen receptor (AR and both estrogen receptors (ERα, ERβ were summarized in the steroid receptor group

  6. Cancer stem cells and differentiation therapy.

    Science.gov (United States)

    Jin, Xiong; Jin, Xun; Kim, Hyunggee

    2017-10-01

    Cancer stem cells can generate tumors from only a small number of cells, whereas differentiated cancer cells cannot. The prominent feature of cancer stem cells is its ability to self-renew and differentiate into multiple types of cancer cells. Cancer stem cells have several distinct tumorigenic abilities, including stem cell signal transduction, tumorigenicity, metastasis, and resistance to anticancer drugs, which are regulated by genetic or epigenetic changes. Like normal adult stem cells involved in various developmental processes and tissue homeostasis, cancer stem cells maintain their self-renewal capacity by activating multiple stem cell signaling pathways and inhibiting differentiation signaling pathways during cancer initiation and progression. Recently, many studies have focused on targeting cancer stem cells to eradicate malignancies by regulating stem cell signaling pathways, and products of some of these strategies are in preclinical and clinical trials. In this review, we describe the crucial features of cancer stem cells related to tumor relapse and drug resistance, as well as the new therapeutic strategy to target cancer stem cells named "differentiation therapy."

  7. DNA repair in murine embryonic stem cells and differentiated cells

    International Nuclear Information System (INIS)

    Tichy, Elisia D.; Stambrook, Peter J.

    2008-01-01

    Embryonic stem (ES) cells are rapidly proliferating, self-renewing cells that have the capacity to differentiate into all three germ layers to form the embryo proper. Since these cells are critical for embryo formation, they must have robust prophylactic mechanisms to ensure that their genomic integrity is preserved. Indeed, several studies have suggested that ES cells are hypersensitive to DNA damaging agents and readily undergo apoptosis to eliminate damaged cells from the population. Other evidence suggests that DNA damage can cause premature differentiation in these cells. Several laboratories have also begun to investigate the role of DNA repair in the maintenance of ES cell genomic integrity. It does appear that ES cells differ in their capacity to repair damaged DNA compared to differentiated cells. This minireview focuses on repair mechanisms ES cells may use to help preserve genomic integrity and compares available data regarding these mechanisms with those utilized by differentiated cells

  8. Identification of Differentially Expressed miRNAs between White and Black Hair Follicles by RNA-Sequencing in the Goat (Capra hircus)

    Science.gov (United States)

    Wu, Zhenyang; Fu, Yuhua; Cao, Jianhua; Yu, Mei; Tang, Xiaohui; Zhao, Shuhong

    2014-01-01

    MicroRNAs (miRNAs) play a key role in many biological processes by regulating gene expression at the post-transcriptional level. A number of miRNAs have been identified from livestock species. However, compared with other animals, such as pigs and cows, the number of miRNAs identified in goats is quite low, particularly in hair follicles. In this study, to investigate the functional roles of miRNAs in goat hair follicles of goats with different coat colors, we sequenced miRNAs from two hair follicles samples (white and black) using Solexa sequencing. A total of 35,604,016 reads were obtained, which included 30,878,637 clean reads (86.73%). MiRDeep2 software identified 214 miRNAs. Among them, 205 were conserved among species and nine were novel miRNAs. Furthermore, DESeq software identified six differentially expressed miRNAs. Quantitative PCR confirmed differential expression of two miRNAs, miR-10b and miR-211. KEGG pathways were analyzed using the DAVID website for the predicted target genes of the differentially expressed miRNAs. Several signaling pathways including Notch and MAPK pathways may affect the process of coat color formation. Our study showed that the identified miRNAs might play an essential role in black and white follicle formation in goats. PMID:24879525

  9. Identification of Differentially Expressed miRNAs between White and Black Hair Follicles by RNA-Sequencing in the Goat (Capra hircus

    Directory of Open Access Journals (Sweden)

    Zhenyang Wu

    2014-05-01

    Full Text Available MicroRNAs (miRNAs play a key role in many biological processes by regulating gene expression at the post-transcriptional level. A number of miRNAs have been identified from livestock species. However, compared with other animals, such as pigs and cows, the number of miRNAs identified in goats is quite low, particularly in hair follicles. In this study, to investigate the functional roles of miRNAs in goat hair follicles of goats with different coat colors, we sequenced miRNAs from two hair follicles samples (white and black using Solexa sequencing. A total of 35,604,016 reads were obtained, which included 30,878,637 clean reads (86.73%. MiRDeep2 software identified 214 miRNAs. Among them, 205 were conserved among species and nine were novel miRNAs. Furthermore, DESeq software identified six differentially expressed miRNAs. Quantitative PCR confirmed differential expression of two miRNAs, miR-10b and miR-211. KEGG pathways were analyzed using the DAVID website for the predicted target genes of the differentially expressed miRNAs. Several signaling pathways including Notch and MAPK pathways may affect the process of coat color formation. Our study showed that the identified miRNAs might play an essential role in black and white follicle formation in goats.

  10. Spaceflight-induced synaptic modifications within hair cells of the mammalian utricle.

    Science.gov (United States)

    Sultemeier, David R; Choy, Kristel R; Schweizer, Felix E; Hoffman, Larry F

    2017-06-01

    Exposure to the microgravity conditions of spaceflight alleviates the load normally imposed by the Earth's gravitational field on the inner ear utricular epithelia. Previous ultrastructural investigations have shown that spaceflight induces an increase in synapse density within hair cells of the rat utricle. However, the utricle exhibits broad physiological heterogeneity across different epithelial regions, and it is unknown whether capabilities for synaptic plasticity generalize to hair cells across its topography. To achieve systematic and broader sampling of the epithelium than was previously conducted, we used immunohistochemistry and volumetric image analyses to quantify synapse distributions across representative utricular regions in specimens from mice exposed to spaceflight (a 15-day mission of the space shuttle Discovery). These measures were compared with similarly sampled Earth-bound controls. Following paraformaldehyde fixation and microdissection, immunohistochemistry was performed on intact specimens to label presynaptic ribbons (anti-CtBP2) and postsynaptic receptor complexes (anti-Shank1A). Synapses were identified as closely apposed pre- and postsynaptic puncta. Epithelia from horizontal semicircular canal cristae served as "within-specimen" controls, whereas utricles and cristae from Earth-bound cohorts served as experimental controls. We found that synapse densities decreased in the medial extrastriolae of microgravity specimens compared with experimental controls, whereas they were unchanged in the striolae and horizontal cristae from the two conditions. These data demonstrate that structural plasticity was topographically localized to the utricular region that encodes very low frequency and static changes in linear acceleration, and illuminates the remarkable capabilities of utricular hair cells for synaptic plasticity in adapting to novel gravitational environments. NEW & NOTEWORTHY Spaceflight imposes a radically different sensory environment

  11. CLRN1 is nonessential in the mouse retina but is required for cochlear hair cell development.

    Directory of Open Access Journals (Sweden)

    Scott F Geller

    2009-08-01

    Full Text Available Mutations in the CLRN1 gene cause Usher syndrome type 3 (USH3, a human disease characterized by progressive blindness and deafness. Clarin 1, the protein product of CLRN1, is a four-transmembrane protein predicted to be associated with ribbon synapses of photoreceptors and cochlear hair cells, and recently demonstrated to be associated with the cytoskeleton. To study Clrn1, we created a Clrn1 knockout (KO mouse and characterized the histological and functional consequences of Clrn1 deletion in the retina and cochlea. Clrn1 KO mice do not develop a retinal degeneration phenotype, but exhibit progressive loss of sensory hair cells in the cochlea and deterioration of the organ of Corti by 4 months. Hair cell stereocilia in KO animals were longer and disorganized by 4 months, and some Clrn1 KO mice exhibited circling behavior by 5-6 months of age. Clrn1 mRNA expression was localized in the retina using in situ hybridization (ISH, laser capture microdissection (LCM, and RT-PCR. Retinal Clrn1 transcripts were found throughout development and adulthood by RT-PCR, although expression peaked at P7 and declined to undetectable levels in adult retina by ISH. LCM localized Clrn1 transcripts to the retinas inner nuclear layer, and WT levels of retinal Clrn1 expression were observed in photoreceptor-less retinas. Examination of Clrn1 KO mice suggests that CLRN1 is unnecessary in the murine retina but essential for normal cochlear development and function. This may reflect a redundancy in the mouse retina not present in human retina. In contrast to mouse KO models of USH1 and USH2, our data indicate that Clrn1 expression in the retina is restricted to the Müller glia. This is a novel finding, as most retinal degeneration associated proteins are expressed in photoreceptors, not in glia. If CLRN1 expression in humans is comparable to the expression pattern observed in mice, this is the first report of an inner retinal protein that, when mutated, causes retinal

  12. Eye and hair colour, skin type and constitutive skin pigmentation as risk factors for basal cell carcinoma and cutaneous malignant melanoma. A Danish case-control study

    DEFF Research Database (Denmark)

    Lock-Andersen, J; Drzewiecki, K T; Wulf, H C

    1999-01-01

    To assess the importance of hair and eye colour, skin type and constitutive skin pigmentation as risk factors for basal cell carcinoma and cutaneous malignant melanoma in fair-skinned Caucasians, we conducted two identical case-control studies in Denmark. We studied 145 cases with basal cell...... the present hair colour and eye colour, and the constitutive skin pigmentation was measured objectively by skin reflectance of UV unexposed buttock skin. There were no differences between basal cell carcinoma cases and controls in hair colour or eye colour or constitutive skin pigmentation, but more cases...... were of skin type II than skin type IV; skin type 11 was a risk factor for basal cell carcinoma with an odds ratio (OR) of 2.3. For cutaneous malignant melanoma, more cases than controls were red-haired or blond and of skin type II, but there was no difference in constitutive skin pigmentation. Hair...

  13. Transcriptome changes during intestinal cell differentiation

    DEFF Research Database (Denmark)

    Tadjali, Mehrdad; Seidelin, Jakob B; Olsen, Jørgen

    2002-01-01

    The expression of 18149 genes have been analysed during the differentiation of the human intestinal cell line Caco-2. cDNA probes from undifferentiated and differentiated Caco-2 cells were separately hybridised to EST DNAs spotted in an array on a nylon membrane. A remarkable change in the transc......The expression of 18149 genes have been analysed during the differentiation of the human intestinal cell line Caco-2. cDNA probes from undifferentiated and differentiated Caco-2 cells were separately hybridised to EST DNAs spotted in an array on a nylon membrane. A remarkable change...... cells by performing reverse transcriptase-polymerase chain reaction on RNA extracted from laser dissected intestinal crypt and villi. In a screen of eight transcripts one - SART3 - was identified as a marker for human colonic crypts....

  14. Calcium-Induced calcium release during action potential firing in developing inner hair cells.

    Science.gov (United States)

    Iosub, Radu; Avitabile, Daniele; Grant, Lisa; Tsaneva-Atanasova, Krasimira; Kennedy, Helen J

    2015-03-10

    In the mature auditory system, inner hair cells (IHCs) convert sound-induced vibrations into electrical signals that are relayed to the central nervous system via auditory afferents. Before the cochlea can respond to normal sound levels, developing IHCs fire calcium-based action potentials that disappear close to the onset of hearing. Action potential firing triggers transmitter release from the immature IHC that in turn generates experience-independent firing in auditory neurons. These early signaling events are thought to be essential for the organization and development of the auditory system and hair cells. A critical component of the action potential is the rise in intracellular calcium that activates both small conductance potassium channels essential during membrane repolarization, and triggers transmitter release from the cell. Whether this calcium signal is generated by calcium influx or requires calcium-induced calcium release (CICR) is not yet known. IHCs can generate CICR, but to date its physiological role has remained unclear. Here, we used high and low concentrations of ryanodine to block or enhance CICR to determine whether calcium release from intracellular stores affected action potential waveform, interspike interval, or changes in membrane capacitance during development of mouse IHCs. Blocking CICR resulted in mixed action potential waveforms with both brief and prolonged oscillations in membrane potential and intracellular calcium. This mixed behavior is captured well by our mathematical model of IHC electrical activity. We perform two-parameter bifurcation analysis of the model that predicts the dependence of IHCs firing patterns on the level of activation of two parameters, the SK2 channels activation and CICR rate. Our data show that CICR forms an important component of the calcium signal that shapes action potentials and regulates firing patterns, but is not involved directly in triggering exocytosis. These data provide important insights

  15. Chromatin in embryonic stem cell neuronal differentiation.

    Science.gov (United States)

    Meshorer, E

    2007-03-01

    Chromatin, the basic regulatory unit of the eukaryotic genetic material, is controlled by epigenetic mechanisms including histone modifications, histone variants, DNA methylation and chromatin remodeling. Cellular differentiation involves large changes in gene expression concomitant with alterations in genome organization and chromatin structure. Such changes are particularly evident in self-renewing pluripotent embryonic stem cells, which begin, in terms of cell fate, as a tabula rasa, and through the process of differentiation, acquire distinct identities. Here I describe the changes in chromatin that accompany neuronal differentiation, particularly of embryonic stem cells, and discuss how chromatin serves as the master regulator of cellular destiny.

  16. Human Pluripotent Stem Cell Differentiation into Functional Epicardial Progenitor Cells

    NARCIS (Netherlands)

    Guadix, Juan Antonio; Orlova, Valeria V.; Giacomelli, Elisa; Bellin, Milena; Ribeiro, Marcelo C.; Mummery, Christine L.; Pérez-Pomares, José M.; Passier, Robert

    2017-01-01

    Human pluripotent stem cells (hPSCs) are widely used to study cardiovascular cell differentiation and function. Here, we induced differentiation of hPSCs (both embryonic and induced) to proepicardial/epicardial progenitor cells that cover the heart during development. Addition of retinoic acid (RA)

  17. Effect of outer hair cell piezoelectricity on high-frequency receptor potentials.

    Science.gov (United States)

    Spector, Alexander A; Brownell, William E; Popel, Aleksander S

    2003-01-01

    The low-pass voltage response of outer hair cells predicted by conventional equivalent circuit analysis would preclude the active force production at high frequencies. We have found that the band pass characteristics can be improved by introducing the piezoelectric properties of the cell wall. In contrast to the conventional analysis, the receptor potential does not tend to zero and at any frequency is greater than a limiting value. In addition, the phase shift between the transduction current and receptor potential tends to zero. The piezoelectric properties cause an additional, strain-dependent, displacement current in the cell wall. The wall strain is estimated on the basis of a model of the cell deformation in the organ of Corti. The limiting value of the receptor potential depends on the ratio of a parameter determined by the piezoelectric coefficients and the strain to the membrane capacitance. In short cells, we have found that for the low-frequency value of about 2-3 mV and the strain level of 0.1% the receptor potential can reach 0.4 mV throughout the whole frequency range. In long cells, we have found that the effect of the piezoelectric properties is much weaker. These results are consistent with major features of the cochlear amplifier.

  18. Round window administration of gentamicin: a new method for the study of ototoxicity of cochlear hair cells.

    Science.gov (United States)

    Husmann, K R; Morgan, A S; Girod, D A; Durham, D

    1998-11-01

    Damage to inner ear sensory hair cells after systemic administration of ototoxic drugs has been documented in humans and animals. Birds have the ability to regenerate new hair cells to replace those damaged by drugs or noise. Unfortunately, the systemic administration of gentamicin damages both ears in a variable fashion with potentially confounding systemic drug effects. We developed a method of direct application of gentamicin to one cochlea of hatchling chickens, allowing the other ear to serve as a within-animal control. We tested variables including the vehicle for application, location of application, dosage, and duration of gentamicin exposure. After 5 or 28 days survival, the percent length damage to the cochlea and regeneration of hair cells was evaluated using scanning electron microscopy. Controls consisted of the opposite unexposed cochlea and additional animals which received saline instead of gentamicin. Excellent damage was achieved using gentamicin-soaked Gelfoam pledgets applied to the round window membrane. The percent length damage could be varied from 15 to 100% by changing the dosage of gentamicin, with exposures as short as 30 min. No damage was observed in control animals. Regeneration of hair cells was observed in both the base and apex by 28 days survival.

  19. Temperature dependency of cupular mechanics and hair cell frequency selectivity in the fish canal lateral line organ

    NARCIS (Netherlands)

    Wiersinga-Post, JEC; van Netten, SM

    2000-01-01

    The mechanical frequency selectivity of the cupula located in the supraorbital lateral line canal and the frequency selectivity of the hair cells driven by the cupula were measured simultaneously in vivo. Laser interferometry was used to measure cupular mechanics and extracellular receptor

  20. Localization and expression of clarin-1, the Clrn1 gene product, in auditory hair cells and photoreceptors

    Science.gov (United States)

    Zallocchi, Marisa; Meehan, Daniel T.; Delimont, Duane; Askew, Charles; Garrige, Suneetha; Gratton, Michael Anne; Rothermund-Franklin, Christie A.; Cosgrove, Dominic

    2009-01-01

    The Usher syndrome 3A (CLRN1) gene encodes clarin-1, which is a member of the tetraspanin family of transmembrane proteins. Although identified more than 6 years ago, little is known about its localization or function in the eye and ear. We developed a polyclonal antibody that react with all clarin-1 isoforms and used it to characterize protein expression in cochlea and retina. In the cochlea, we observe clarin-1expression in the stereocilia of P0 mice, and in synaptic terminals present at the base of the auditory hair cells from E18 to P6. In the retina, clarin-1 localizes to the connecting cilia, inner segment of photoreceptors and to the ribbon synapses. RT-PCR from P0 cochlea and P28 retina show mRNAs encoding only isoforms 2 and 3. Western-blots show that only isoform 2 is present in protein extracts from these same tissues. We examined clarin-1 expression in the immortomouse-derived hair cell line UB/OC-1. Only isoform 2 is expressed in UB/OC-1 at both mRNA and protein levels, suggesting this isoform is biologically relevant to hair cell function. The protein co-localizes with microtubules and post-transgolgi vesicles. The sub-cellular localization of clarin-1 in hair cells and photoreceptors suggests it functions at both the basal and apical poles of neurosensoriepithelia. PMID:19539019

  1. The role of hair cells, cilia and ciliary motility in otolith formation in the zebrafish otic vesicle.

    Science.gov (United States)

    Stooke-Vaughan, Georgina A; Huang, Peng; Hammond, Katherine L; Schier, Alexander F; Whitfield, Tanya T

    2012-05-01

    Otoliths are biomineralised structures required for the sensation of gravity, linear acceleration and sound in the zebrafish ear. Otolith precursor particles, initially distributed throughout the otic vesicle lumen, become tethered to the tips of hair cell kinocilia (tether cilia) at the otic vesicle poles, forming two otoliths. We have used high-speed video microscopy to investigate the role of cilia and ciliary motility in otolith formation. In wild-type ears, groups of motile cilia are present at the otic vesicle poles, surrounding the immotile tether cilia. A few motile cilia are also found on the medial wall, but most cilia (92-98%) in the otic vesicle are immotile. In mutants with defective cilia (iguana) or ciliary motility (lrrc50), otoliths are frequently ectopic, untethered or fused. Nevertheless, neither cilia nor ciliary motility are absolutely required for otolith tethering: a mutant that lacks cilia completely (MZovl) is still capable of tethering otoliths at the otic vesicle poles. In embryos with attenuated Notch signalling [mindbomb mutant or Su(H) morphant], supernumerary hair cells develop and otolith precursor particles bind to the tips of all kinocilia, or bind directly to the hair cells' apical surface if cilia are absent [MZovl injected with a Su(H)1+2 morpholino]. However, if the first hair cells are missing (atoh1b morphant), otolith formation is severely disrupted and delayed. Our data support a model in which hair cells produce an otolith precursor-binding factor, normally localised to tether cell kinocilia. We also show that embryonic movement plays a minor role in the formation of normal otoliths.

  2. Protective effect of hexane and ethanol extract of piper longum L. On gentamicin-induced hair cell loss in neonatal cultures.

    Science.gov (United States)

    Yadav, Mukesh Kumar; Choi, June; Song, Jae-Jun

    2014-03-01

    Gentamicin (GM) is a commonly used aminoglycoside antibiotic that generates free oxygen radicals within the inner ear, which can cause vestibulo-cochlear toxicity and permanent damage to the sensory hair cells and neurons. Piper longum L. (PL) is a well-known spice and traditional medicine in Asia and Pacific islands, which has been reported to exhibit a wide spectrum of activity, including antioxidant activity. In this study, we evaluated the effect of hexane:ethanol (2:8) PL extract (subfraction of PL [SPL] extract) on GM-induced hair cell loss in basal, middle and apical regions in a neonatal cochlea cultures. The protective effects of SPL extract were measured by phalloidin staining of cultures from postnatal day 2-3 mice with GM-induced hair cell loss. The anti-apoptosis activity of SPL extract was measured using double labeling by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and myosin-7a staining. The radical-scavenging activity of SPL extract was assessed using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. SPL extract at a concentration of 1 µg/mL significantly inhibited GM-induced hair cell loss at basal and middle region of cochlea, while 5 µg/mL was effective against apical region hair cell loss. The protective effect of SPL extract was concentration dependent and hair cells retained their stereocilia in explants treated with SPL extract prior to treatment with 0.3 mM GM. SPL extract decreased GM-induced apoptosis of hair cells as assessed by TUNEL staining. The outer hair and inner hair counts were not decreased in SPL extract treated groups in compare to GM treated explants. Additionally, SPL extract showed concentration dependent radical scavenging activity in a DPPH assay. An anti-apoptosis effect and potent radical scavenger activity of SPL extract protects from GM-induced hair cell loss at basal, middle and apical regions in neonatal cochlea cultures.

  3. Thermal noise and the incessant vibration of the outer hair cells in the cochlea

    Directory of Open Access Journals (Sweden)

    W. Fritze

    1998-01-01

    Full Text Available The continual exposure of outer hair cells (OHCs to thermal noise causes vibrations in resonant frequency. As these vibrations are backprojected, they should be recordable as audiofrequencies in the outer ear canal. But even though they are likely to be amplified in some areas by clustering in terms of the chaos theory, they cannot be picked up in the outer ear canal by currently available recording technologies. Conditions change in the presence of pathology, e.g. loss of OHCs and fibrous replacement: Clusters grow in size and amplitudes become larger so that the vibrations can be picked up as spontaneous oto-acoustic emissions (SOAEs in the outer ear canal. Efforts are needed to demonstrate the presence of physiological OHC vibrations (emission by incessant vibration, EIV by processing auditory recordings with statistical methods.

  4. Dynamics of Lgr6+ Progenitor Cells in the Hair Follicle, Sebaceous Gland, and Interfollicular Epidermis

    Directory of Open Access Journals (Sweden)

    Anja Füllgrabe

    2015-11-01

    Full Text Available The dynamics and interactions between stem cell pools in the hair follicle (HF, sebaceous gland (SG, and interfollicular epidermis (IFE of murine skin are still poorly understood. In this study, we used multicolor lineage tracing to mark Lgr6-expressing basal cells in the HF isthmus, SG, and IFE. We show that these Lgr6+ cells constitute long-term self-renewing populations within each compartment in adult skin. Quantitative analysis of clonal dynamics revealed that the Lgr6+ progenitor cells compete neutrally in the IFE, isthmus, and SG, indicating population asymmetry as the underlying mode of tissue renewal. Transcriptional profiling of Lgr6+ and Lgr6− cells did not reveal a distinct Lgr6-associated gene expression signature, raising the question of whether Lgr6 expression requires extrinsic niche signals. Our results elucidate the interrelation and behavior of Lgr6+ populations in the IFE, HF, and SG and suggest population asymmetry as a common mechanism for homeostasis in several epithelial skin compartments.

  5. Recent Advancements in the Regeneration of Auditory Hair Cells and Hearing Restoration

    Directory of Open Access Journals (Sweden)

    Rahul Mittal

    2017-07-01

    Full Text Available Neurosensory responses of hearing and balance are mediated by receptors in specialized neuroepithelial sensory cells. Any disruption of the biochemical and molecular pathways that facilitate these responses can result in severe deficits, including hearing loss and vestibular dysfunction. Hearing is affected by both environmental and genetic factors, with impairment of auditory function being the most common neurosensory disorder affecting 1 in 500 newborns, as well as having an impact on the majority of elderly population. Damage to auditory sensory cells is not reversible, and if sufficient damage and cell death have taken place, the resultant deficit may lead to permanent deafness. Cochlear implants are considered to be one of the most successful and consistent treatments for deaf patients, but only offer limited recovery at the expense of loss of residual hearing. Recently there has been an increased interest in the auditory research community to explore the regeneration of mammalian auditory hair cells and restoration of their function. In this review article, we examine a variety of recent therapies, including genetic, stem cell and molecular therapies as well as discussing progress being made in genome editing strategies as applied to the restoration of hearing function.

  6. Control of differentiation of melanoma cells

    International Nuclear Information System (INIS)

    Eguchi, Goro

    1980-01-01

    To develop the method to induce the appearance of differentiation in amelanotic melanoma, experimental control of differentiation in B-16 melanoma cells of mice was discussed. Human melanoma cells and yellow melanin pigment cells useful for a fundamental study of radiotherapy for cancer were cultured and were differentiated into some lines. Melanotic B-16 cells and amelanotic B-16 cells were irradiated with thermal neutron (neutron: 2.7 x 10 12 , γ-dose: 32.3 rad) after they were cultured in culture solution containing 10 γ/ml of 10 B-dopa for 13 hours. A fine structure 5 hours after the irradiation in one of 5 experimental cases showed aggregated disintegration of melanin pigment particles, markedly deformed and fragmentized nucleus, and structural changes in cell membrane. (Tsunoda, M.)

  7. Noise-induced nitrotyrosine increase and outer hair cell death in guinea pig cochlea.

    Science.gov (United States)

    Han, Wei-ju; Shi, Xiao-rui; Nuttall, Alfred

    2013-01-01

    Modern research has provided new insights into the biological mechanisms of noise-induced hearing loss, and a number of studies showed the appearance of increased reactive oxygen species (ROS) and reactive nitrogen species (RNS) during and after noise exposure. This study was designed to investigate the noise exposure induced nitrotyrosine change and the mechanism of outer hair cells death in guinea pig cochlea. Thirty guinea pigs were used in this study. The experimental animals were either exposed for 4 hours per day to broadband noise at 122 dB SPL (A-weighted) for 2 consecutive days or perfused cochleae with 5 mg/ml of the SIN1 solutions, an exogenous NO and superoxide donor, for 30 minutes. Then the cochleae of the animals were dissected. Propidium iodide (PI), a DNA intercalating fluorescent probe, was used to trace morphological changes in OHC nuclei. The distribution of nitrotyrosine (NT) in the organ of Corti and the cochlear lateral wall tissue from the guinea pigs were examined using fluorescence immunohistochemistry method. Whole mounts of organ of Corti were prepared. Morphological and fluorescent changes were examined under a confocal microscope. Either after noise exposure or after SIN1 perfusion, outer hair cells (OHCs) death with characteristics of both apoptotic and necrotic degradation appeared. Nitrotyrosine immunolabeling could be observed in the OHCs from the control animals. After noise exposure, NT immunostaining became much greater than the control animals in OHCs. The apoptotic OHC has significant increase of nitrotyrosine in and around the nucleus following noise exposure. In the normal later wall of cochleae, relatively weak nitrotyrosine immunolabeling could be observed. After noise exposure, nitrotyrosine immunoactivity became stronger in stria vascularis. Noise exposure induced increase of nitrotyrosine production is associated with OHCs death suggesting reactive nitrogen species participation in the cochlear pathophysiology of noise

  8. Nucleotide excision repair in differentiated cells

    Energy Technology Data Exchange (ETDEWEB)

    Wees, Caroline van der [Department of Toxicogenetics, Leiden University Medical Center, Leiden (Netherlands); Department of Cardiology, Leiden University Medical Center, Leiden (Netherlands); Jansen, Jacob [Department of Toxicogenetics, Leiden University Medical Center, Leiden (Netherlands); Vrieling, Harry [Department of Toxicogenetics, Leiden University Medical Center, Leiden (Netherlands); Laarse, Arnoud van der [Department of Cardiology, Leiden University Medical Center, Leiden (Netherlands); Zeeland, Albert van [Department of Toxicogenetics, Leiden University Medical Center, Leiden (Netherlands); Mullenders, Leon [Department of Toxicogenetics, Leiden University Medical Center, Leiden (Netherlands)]. E-mail: l.mullenders@lumc.nl

    2007-01-03

    Nucleotide excision repair (NER) is the principal pathway for the removal of a wide range of DNA helix-distorting lesions and operates via two NER subpathways, i.e. global genome repair (GGR) and transcription-coupled repair (TCR). Although detailed information is available on expression and efficiency of NER in established mammalian cell lines, little is known about the expression of NER pathways in (terminally) differentiated cells. The majority of studies in differentiated cells have focused on repair of UV-induced cyclobutane pyrimidine dimers (CPD) and 6-4-photoproducts (6-4PP) because of the high frequency of photolesions at low level of toxicity and availability of sensitive technologies to determine photolesions in defined regions of the genome. The picture that emerges from these studies is blurred and rather complex. Fibroblasts and terminally differentiated myocytes of the rat heart display equally efficient GGR of 6-4PP but poor repair of CPD due to the absence of p48 expression. This repair phenotype is clearly different from human terminal differentiated neurons. Furthermore, both cell types were found to carry out TCR of CPD, thus mimicking the repair phenotype of established rodent cell lines. In contrast, in intact rat spermatogenic cells repair was very inefficient at the genome overall level and in transcriptionally active genes indicating that GGR and TCR are non-functional. Also, non-differentiated mouse embryonic stem (ES) cells exhibit low levels of NER after UV irradiation. However, the mechanisms that lead to low NER activity are clearly different: in differentiated spermatogenic cells differences in chromatin compaction and sequestering of NER proteins may underlie the lack of NER activity in pre-meiotic cells, whereas in non-differentiated ES cells NER is impaired by a strong apoptotic response.

  9. Multifunctional Merkel cells: their roles in electromagnetic reception, finger-print formation, Reiki, epigenetic inheritance and hair form.

    Science.gov (United States)

    Irmak, M Kemal

    2010-08-01

    Merkel cells are located in glabrous and hairy skin and in some mucosa. They are characterized by dense-core secretory granules and cytoskeletal filaments. They are attached to neighboring keratinocytes by desmosomes and contain melanosomes similar to keratinocytes. They are excitable cells in close contact with sensory nerve endings but their function is still unclear. In this review, following roles are attributed for the first time to the Merkel cells: (1) melanosomes in Merkel cells may be involved in mammalian magnetoreception. In this model melanosome as a biological magnetite is connected by cytoskeletal filaments to mechanically gated ion channels embedded in the Merkel cell membrane. The movement of melanosome with the changing electromagnetic field may open ion channels directly producing a receptor potential that can be transmitted to brain via sensory neurons. (2) Merkel cells may be involved in finger-print formation: Merkel cells in glabrous skin are located at the base of the epidermal ridges the type of which defines the finger-print pattern. Finger-print formation starts at the 10th week of pregnancy after the arrival of Merkel cells. Keratinocyte proliferation and the buckling process observed in the basal layer of epidermis resulting in the epidermal ridges may be controlled and formed by Merkel cells. (3) Brain-Merkel cell connection is bi-directional and Merkel cells not only absorb but also radiate the electromagnetic frequencies. Hence, efferent aspects of the palmar and plantar Merkel nerve endings may form the basis of the biofield modalities such as Reiki, therapeutic touch and telekinesis. (4) Adaptive geographic variations such as skin color, craniofacial morphology and hair form result from interactions between environmental factors and epigenetic inheritance system. While environmental factors produce modifications in the body, they simultaneously induce epigenetic modifications in the oocytes and in this way adaptive changes could be

  10. Human Pluripotent Stem Cell Differentiation into Functional Epicardial Progenitor Cells

    Directory of Open Access Journals (Sweden)

    Juan Antonio Guadix

    2017-12-01

    Full Text Available Summary: Human pluripotent stem cells (hPSCs are widely used to study cardiovascular cell differentiation and function. Here, we induced differentiation of hPSCs (both embryonic and induced to proepicardial/epicardial progenitor cells that cover the heart during development. Addition of retinoic acid (RA and bone morphogenetic protein 4 (BMP4 promoted expression of the mesodermal marker PDGFRα, upregulated characteristic (proepicardial progenitor cell genes, and downregulated transcription of myocardial genes. We confirmed the (proepicardial-like properties of these cells using in vitro co-culture assays and in ovo grafting of hPSC-epicardial cells into chick embryos. Our data show that RA + BMP4-treated hPSCs differentiate into (proepicardial-like cells displaying functional properties (adhesion and spreading over the myocardium of their in vivo counterpart. The results extend evidence that hPSCs are an excellent model to study (proepicardial differentiation into cardiovascular cells in human development and evaluate their potential for cardiac regeneration. : The authors have shown that hPSCs can be instructed in vitro to differentiate into a specific cardiac embryonic progenitor cell population called the proepicardium. Proepicardial cells are required for normal formation of the heart during development and might contribute to the development of cell-based therapies for heart repair. Keywords: human pluripotent stem cells, proepicardium, progenitor cells, cardiovascular, differentiation

  11. Localization of calcium in the sensory cells of the Dionaea trigger hair by laser micro-mass analysis (LAMMA)

    International Nuclear Information System (INIS)

    Buchen, B.; Schröder, W.H.

    1986-01-01

    In Dionaea, mechanical bending of the trigger hair induces action potentials which spread over the trap lobes to the motor cells (review Bentrup 1979). The perception of the stimulus and its transformation into a physiological signal occurs in a ring of specialized epidermal cells in the indentation zone of the trigger hair. These sensory cells (Haberlandt 1906) are characterized by a highly evolved ER complex at the apical and the basal cell pole. The ER surrounds several vacuoles containing poly phenols (Buchen et al. 1983). In order to study the function of these cell structures in sensory transduction, we examined the development of the trigger hair (Casser et al. 1985). During its development, a change in the membrane potential could be measured for the first time when the structural polarity of the sensory cell was established. Yet the short action potentials which are necessary for trap closure were fired only if the typical ER complex in the cell poles was visible. Since membrane potential changes are mediated by ions, we tried to identify and to localize ions possibly involved in these processes. Here we present the first results

  12. Nanotopographical Control of Stem Cell Differentiation

    Directory of Open Access Journals (Sweden)

    Laura E. McNamara

    2010-01-01

    Full Text Available Stem cells have the capacity to differentiate into various lineages, and the ability to reliably direct stem cell fate determination would have tremendous potential for basic research and clinical therapy. Nanotopography provides a useful tool for guiding differentiation, as the features are more durable than surface chemistry and can be modified in size and shape to suit the desired application. In this paper, nanotopography is examined as a means to guide differentiation, and its application is described in the context of different subsets of stem cells, with a particular focus on skeletal (mesenchymal stem cells. To address the mechanistic basis underlying the topographical effects on stem cells, the likely contributions of indirect (biochemical signal-mediated and direct (force-mediated mechanotransduction are discussed. Data from proteomic research is also outlined in relation to topography-mediated fate determination, as this approach provides insight into the global molecular changes at the level of the functional effectors.

  13. Biophysical regulation of stem cell differentiation.

    Science.gov (United States)

    Govey, Peter M; Loiselle, Alayna E; Donahue, Henry J

    2013-06-01

    Bone adaptation to its mechanical environment, from embryonic through adult life, is thought to be the product of increased osteoblastic differentiation from mesenchymal stem cells. In parallel with tissue-scale loading, these heterogeneous populations of multipotent stem cells are subject to a variety of biophysical cues within their native microenvironments. Bone marrow-derived mesenchymal stem cells-the most broadly studied source of osteoblastic progenitors-undergo osteoblastic differentiation in vitro in response to biophysical signals, including hydrostatic pressure, fluid flow and accompanying shear stress, substrate strain and stiffness, substrate topography, and electromagnetic fields. Furthermore, stem cells may be subject to indirect regulation by mechano-sensing osteocytes positioned to more readily detect these same loading-induced signals within the bone matrix. Such paracrine and juxtacrine regulation of differentiation by osteocytes occurs in vitro. Further studies are needed to confirm both direct and indirect mechanisms of biophysical regulation within the in vivo stem cell niche.

  14. Transplantation of an LGR6+ Epithelial Stem Cell-Enriched Scaffold for Repair of Full-Thickness Soft-Tissue Defects: The In Vitro Development of Polarized Hair-Bearing Skin.

    Science.gov (United States)

    Lough, Denver M; Wetter, Nathan; Madsen, Christopher; Reichensperger, Joel; Cosenza, Nicole; Cox, Lisa; Harrison, Carrie; Neumeister, Michael W

    2016-02-01

    Recent literature has shown that full-thickness wounds, devoid of the stem cell niche, can subsequently be reconstructed with functional skin elements following migration of the LGR6 epithelial stem cell into the wound bed. In this study, the authors use a variety of LGR6 epithelial stem cell-seeded scaffolds to determine therapeutic utility and regenerative potential in the immediate reconstruction of full-thickness wounds. Isolated LGR6 epithelial stem cells were seeded onto a spectrum of acellular matrices and monitored in both in vitro and in vivo settings to determine their relative capacity to regenerate tissues and heal wounds. Wound beds containing LGR6 stem cell-seeded scaffolds showed significantly augmented rates of healing, epithelialization, and hair growth compared with controls. Gene and proteomic expression studies indicate that LGR6 stem cell-seeded constructs up-regulate WNT, epidermal growth factor, and angiogenesis pathways. Finally, the addition of stromal vascular fraction to LGR6 stem cell-seeded constructs induces polarized tissue formation, nascent hair growth, and angiogenesis within wounds. LGR6 stem cells are able to undergo proliferation, differentiation, and migration following seeding onto a variety of collagen-based scaffolding. In addition, deployment of these constructs induces epithelialization, hair growth, and angiogenesis within wound beds. The addition of stromal vascular fraction to LGR6 stem cell-containing scaffolds initiated an early form of tissue polarization, providing for the first time a clinically applicable stem cell-based construct that is capable of the repair of full-thickness wounds and hair regeneration. Therapeutic, V.

  15. The genetic network controlling plasma cell differentiation.

    Science.gov (United States)

    Nutt, Stephen L; Taubenheim, Nadine; Hasbold, Jhagvaral; Corcoran, Lynn M; Hodgkin, Philip D

    2011-10-01

    Upon activation by antigen, mature B cells undergo immunoglobulin class switch recombination and differentiate into antibody-secreting plasma cells, the endpoint of the B cell developmental lineage. Careful quantitation of these processes, which are stochastic, independent and strongly linked to the division history of the cell, has revealed that populations of B cells behave in a highly predictable manner. Considerable progress has also been made in the last few years in understanding the gene regulatory network that controls the B cell to plasma cell transition. The mutually exclusive transcriptomes of B cells and plasma cells are maintained by the antagonistic influences of two groups of transcription factors, those that maintain the B cell program, including Pax5, Bach2 and Bcl6, and those that promote and facilitate plasma cell differentiation, notably Irf4, Blimp1 and Xbp1. In this review, we discuss progress in the definition of both the transcriptional and cellular events occurring during late B cell differentiation, as integrating these two approaches is crucial to defining a regulatory network that faithfully reflects the stochastic features and complexity of the humoral immune response. 2011 Elsevier Ltd. All rights reserved.

  16. d-Tubocurarine and Berbamine: Alkaloids That Are Permeant Blockers of the Hair Cell's Mechano-Electrical Transducer Channel and Protect from Aminoglycoside Toxicity

    Directory of Open Access Journals (Sweden)

    Nerissa K. Kirkwood

    2017-09-01

    Full Text Available Aminoglycoside antibiotics are widely used for the treatment of life-threatening bacterial infections, but cause permanent hearing loss in a substantial proportion of treated patients. The sensory hair cells of the inner ear are damaged following entry of these antibiotics via the mechano-electrical transducer (MET channels located at the tips of the hair cell's stereocilia. d-Tubocurarine (dTC is a MET channel blocker that reduces the loading of gentamicin-Texas Red (GTTR into rat cochlear hair cells and protects them from gentamicin treatment. Berbamine is a structurally related alkaloid that reduces GTTR labeling of zebrafish lateral-line hair cells and protects them from aminoglycoside-induced cell death. Both compounds are thought to reduce aminoglycoside entry into hair cells through the MET channels. Here we show that dTC (≥6.25 μM or berbamine (≥1.55 μM protect zebrafish hair cells in vivo from neomycin (6.25 μM, 1 h. Protection of zebrafish hair cells against gentamicin (10 μM, 6 h was provided by ≥25 μM dTC or ≥12.5 μM berbamine. Hair cells in mouse cochlear cultures are protected from longer-term exposure to gentamicin (5 μM, 48 h by 20 μM berbamine or 25 μM dTC. Berbamine is, however, highly toxic to mouse cochlear hair cells at higher concentrations (≥30 μM whilst dTC is not. The absence of toxicity in the zebrafish assays prompts caution in extrapolating results from zebrafish neuromasts to mammalian cochlear hair cells. MET current recordings from mouse outer hair cells (OHCs show that both compounds are permeant open-channel blockers, rapidly and reversibly blocking the MET channel with half-blocking concentrations of 2.2 μM (dTC and 2.8 μM (berbamine in the presence of 1.3 mM Ca2+ at −104 mV. Berbamine, but not dTC, also blocks the hair cell's basolateral K+ current, IK,neo, and modeling studies indicate that berbamine permeates the MET channel more readily than dTC. These studies reveal key properties of

  17. Stimulation of the inner hair cell stereocilia: A sensitivity and noise analysis

    Science.gov (United States)

    Sasmal, Aritra; Grosh, Karl

    2018-05-01

    The inner hair cell (IHC) hair bundles (HBs) of the mammalian cochlea are located in a 2-6 µm wide fluid filled gap of the sub-tectorial space (STS) between the tectorial membrane (TM) and the reticular lamina (RL) and are excited by the radial flow of the viscous endolymphatic fluid. According to the fluctuation dissipation theorem, the viscosity of the STS fluid that couples the HBs to the radial motion of the TM also gives rise to mechanical fluctuations which are transduced into current noise by the mechano-electric transduction (MET) channels at the tip of the HBs. Conversely, the inherent stochasticity of the MET channels leads to fluctuations in the resting tension of the tip links and induce dissipation. In this study, we quantified the viscous and channel noise in the gerbil cochlea through an analytic model. The channel noise was found to be the dominant noise at the characteristic frequency (CF) of the apex while viscous noise was the dominant noise source at the CF of the base. The net root mean square (RMS) fluctuation of the HB motion was predicted to be at least 1.18 nm at the base and 2.72 nm at the apex, while the narrowband threshold TM radial motion was estimated to be 5 pm at the base and 0.1 nm at the apex. We studied the trade-off between sensitivity and noise on the HBs by varying the height of the HBs and predicted that the taller HBs have a lower TM shear displacement threshold in spite of experiencing higher viscous noise force.

  18. 3-Deoxysappanchalcone Promotes Proliferation of Human Hair Follicle Dermal Papilla Cells and Hair Growth in C57BL/6 Mice by Modulating WNT/β-Catenin and STAT Signaling

    Science.gov (United States)

    Kim, Young Eun; Choi, Hyung Chul; Lee, In-Chul; Yuk, Dong Yeon; Lee, Hyosung; Choi, Bu Young

    2016-01-01

    3-Deoxysappanchalcone (3-DSC) has been reported to possess anti-allergic, antiviral, anti-inflammatory and antioxidant activities. In the present study, we investigated the effects of 3-DSC on the proliferation of human hair follicle dermal papilla cells (HDPCs) and mouse hair growth in vivo. A real-time cell analyzer system, luciferase assay, Western blot and real-time polymerase chain reaction (PCR) were employed to measure the biochemical changes occurring in HDPCs in response to 3-DSC treatment. The effect of 3-DSC on hair growth in C57BL/6 mice was also examined. 3-DSC promoted the proliferation of HDPCs, similar to Tofacitinib, an inhibitor of janus-activated kinase (JAK). 3-DSC promoted phosphorylation of β-catenin and transcriptional activation of the T-cell factor. In addition, 3-DSC potentiated interleukin-6 (IL-6)-induced phosphorylation and subsequent transactivation of signal transducer and activator of transcription-3 (STAT3), thereby increasing the expression of cyclin-dependent kinase-4 (Cdk4), fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF). On the contrary, 3-DSC attenuated STAT6 mRNA expression and IL4-induced STAT6 phosphorylation in HDPCs. Finally, we observed that topical application of 3-DSC promoted the anagen phase of hair growth in C57BL/6 mice. 3-DSC stimulates hair growth possibly by inducing proliferation of follicular dermal papilla cells via modulation of WNT/β-catenin and STAT signaling. PMID:27795451

  19. Hair Removal

    DEFF Research Database (Denmark)

    Hædersdal, Merete

    2011-01-01

    Hair removal with optical devices has become a popular mainstream treatment that today is considered the most efficient method for the reduction of unwanted hair. Photothermal destruction of hair follicles constitutes the fundamental concept of hair removal with red and near-infrared wavelengths...... suitable for targeting follicular and hair shaft melanin: normal mode ruby laser (694 nm), normal mode alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), long-pulse Nd:YAG laser (1,064 nm), and intense pulsed light (IPL) sources (590-1,200 nm). The ideal patient has thick dark terminal hair......, white skin, and a normal hormonal status. Currently, no method of lifelong permanent hair eradication is available, and it is important that patients have realistic expectations. Substantial evidence has been found for short-term hair removal efficacy of up to 6 months after treatment with the available...

  20. Hair removal

    DEFF Research Database (Denmark)

    Haedersdal, Merete; Haak, Christina S

    2011-01-01

    Hair removal with optical devices has become a popular mainstream treatment that today is considered the most efficient method for the reduction of unwanted hair. Photothermal destruction of hair follicles constitutes the fundamental concept of hair removal with red and near-infrared wavelengths...... suitable for targeting follicular and hair shaft melanin: normal mode ruby laser (694 nm), normal mode alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), long-pulse Nd:YAG laser (1,064 nm), and intense pulsed light (IPL) sources (590-1,200 nm). The ideal patient has thick dark terminal hair......, white skin, and a normal hormonal status. Currently, no method of lifelong permanent hair eradication is available, and it is important that patients have realistic expectations. Substantial evidence has been found for short-term hair removal efficacy of up to 6 months after treatment with the available...

  1. Thrombopoietin inhibits murine mast cell differentiation

    Science.gov (United States)

    Martelli, Fabrizio; Ghinassi, Barbara; Lorenzini, Rodolfo; Vannucchi, Alessandro M; Rana, Rosa Alba; Nishikawa, Mitsuo; Partamian, Sandra; Migliaccio, Giovanni; Migliaccio, Anna Rita

    2009-01-01

    We have recently shown that Mpl, the thrombopoietin receptor, is expressed on murine mast cells and on their precursors and that targeted deletion of the Mpl gene increases mast cell differentiation in mice. Here we report that treatment of mice with thrombopoietin, or addition of this growth factor to bone marrow-derived mast cell cultures, severely hampers the generation of mature cells from their precursors by inducing apoptosis. Analysis of the expression profiling of mast cells obtained in the presence of thrombopoietin suggests that thrombopoietin induces apoptosis of mast cells by reducing expression of the transcription factor Mitf and its target anti-apoptotic gene Bcl2. PMID:18276801

  2. The passive cable properties of hair cell stereocilia and their contribution to somatic capacitance measurements.

    Science.gov (United States)

    Breneman, Kathryn D; Highstein, Stephen M; Boyle, Richard D; Rabbitt, Richard D

    2009-01-01

    Somatic measurements of whole-cell capacitance are routinely used to understand physiologic events occurring in remote portions of cells. These studies often assume the intracellular space is voltage-clamped. We questioned this assumption in auditory and vestibular hair cells with respect to their stereocilia based on earlier studies showing that neurons, with radial dimensions similar to stereocilia, are not always isopotential under voltage-clamp. To explore this, we modeled the stereocilia as passive cables with transduction channels located at their tips. We found that the input capacitance measured at the soma changes when the transduction channels at the tips of the stereocilia are open compared to when the channels are closed. The maximum capacitance is felt with the transducer closed but will decrease as the transducer opens due to a length-dependent voltage drop along the stereocilium length. This potential drop is proportional to the intracellular resistance and stereocilium tip conductance and can produce a maximum capacitance error on the order of fF for single stereocilia and pF for the bundle.

  3. Repeated exposure to hair dye induces regulatory T cells in mice

    DEFF Research Database (Denmark)

    Rubin, I M C; Dabelsteen, S; Nielsen, M M

    2010-01-01

    We have recently shown that commercial p-phenylenediamine (PPD)-containing hair dyes are potent immune activators that lead to severe contact hypersensitivity in an animal model. However, only a minority of people exposed to permanent hair dyes develops symptomatic contact hypersensitivity...

  4. Hair cosmetics

    OpenAIRE

    Nina Madnani; Kaleem Khan

    2013-01-01

    The hair cosmetic industry has undergone a revolutionary change over the last two decades. The focus has dramatically veered from merely cleaning to repair, increasing the tensile strength, reducing oxidative damage, and stimulating growth. Newer shorter procedures to make hair look naturally more lustrous, smooth, and manageable have evolved. Specialized grooming products have been formulated to cleanse, calm, and condition the hair, and are tailored for different hair-types, for example, dr...

  5. Hair Interactions

    OpenAIRE

    Cani , Marie-Paule; Bertails , Florence

    2006-01-01

    International audience; Processing interactions is one of the main challenges in hair animation. Indeed, in addition to the collisions with the body, an extremely large number of contacts with high friction rates are permanently taking place between individual hair strands. Simulating the latter is essential: without hair self-interactions, strands would cross each other during motion or come to rest at the same location, yielding unrealistic behavior and a visible lack of hair volume. This c...

  6. Mechanism of action of minoxidil in the treatment of androgenetic alopecia is likely mediated by mitochondrial adenosine triphosphate synthase-induced stem cell differentiation.

    Science.gov (United States)

    Goren, A; Naccarato, T; Situm, M; Kovacevic, M; Lotti, T; McCoy, J

    2017-01-01

    Topical minoxidil is the only topical drug approved by the US Food and Drug Administration (FDA) for the treatment of androgenetic alopecia. However, the exact mechanism by which minoxidil stimulates anagen phase and promotes hair growth is not fully understood. In the late telegen phase of the hair follicle growth cycle, stem cells located in the bulge region differentiate and re-enter anagen phase, a period of growth lasting 2-6 years. In androgenetic alopecia, the anagen phase is shortened and a progressive miniaturization of hair follicles occurs, eventually leading to hair loss. Several studies have demonstrated that minoxidil increases the amount of intracellular Ca2+, which has been shown to up-regulate the enzyme adenosine triphosphate (ATP) synthase. A recent study demonstrated that ATP synthase, independent of its role in ATP synthesis, promotes stem cell differentiation. As such, we propose that minoxidil induced Ca2+ influx can increase stem cell differentiation and may be a key factor in the mechanism by which minoxidil facilitates hair growth. Based on our theory, we provide a roadmap for the development of a new class of drugs for the treatment of androgenetic alopecia.

  7. Hair cosmetics

    Directory of Open Access Journals (Sweden)

    Nina Madnani

    2013-01-01

    Full Text Available The hair cosmetic industry has undergone a revolutionary change over the last two decades. The focus has dramatically veered from merely cleaning to repair, increasing the tensile strength, reducing oxidative damage, and stimulating growth. Newer shorter procedures to make hair look naturally more lustrous, smooth, and manageable have evolved. Specialized grooming products have been formulated to cleanse, calm, and condition the hair, and are tailored for different hair-types, for example, dry, dry-damaged, oily, colored, and gray hair. Other products are formulated to alter the color or structure of the hair shaft, for example, hair dyes, perming/relaxing. Hair sprays and waxes/gels, can alter the ′lift′ of the hair-shaft. Although dermatologists are experts in managing scalp and hair diseases, the esthetic applications of newer cosmetic therapies still remain elusive. This article attempts to fill the lacunae in our knowledge of hair cosmetics and esthetic procedures relevant in today′s rapidly changing beauty-enhancing industry, with special emphasis on the Indian scenario for chemical and ′natural′ hair products.

  8. Neomycin damage and regeneration of hair cells in both mechanoreceptor and electroreceptor lateral line organs of the larval Siberian sturgeon (Acipenser baerii).

    Science.gov (United States)

    Fan, Chunxin; Zou, Sha; Wang, Jian; Zhang, Bo; Song, Jiakun

    2016-05-01

    The lateral line found in some amphibians and fishes has two distinctive classes of sensory organs: mechanoreceptors (neuromasts) and electroreceptors (ampullary organs). Hair cells in neuromasts can be damaged by aminoglycoside antibiotics and they will regenerate rapidly afterward. Aminoglycoside sensitivity and the capacity for regeneration have not been investigated in ampullary organs. We treated Siberian sturgeon (Acipenser baerii) larvae with neomycin and observed loss and regeneration of sensory hair cells in both organs by labeling with DASPEI and scanning electron microscopy (SEM). The numbers of sensory hair cells in both organs were reduced to the lowest levels at 6 hours posttreatment (hpt). New sensory hair cells began to appear at 12 hpt and were regenerated completely in 7 days. To reveal the possible mechanism for ampullary hair cell regeneration, we analyzed cell proliferation and the expression of neural placodal gene eya1 during regeneration. Both cell proliferation and eya1 expression were concentrated in peripheral mantle cells and both increased to the highest level at 12 hpt, which is consistent with the time course for regeneration of the ampullary hair cells. Furthermore, we used Texas Red-conjugated gentamicin in an uptake assay following pretreatment with a cation channel blocker (amiloride) and found that entry of the antibiotic was suppressed in both organs. Together, our results indicate that ampullary hair cells in Siberian sturgeon larvae can be damaged by neomycin exposure and they can regenerate rapidly. We suggest that the mechanisms for aminoglycoside uptake and hair cell regeneration are conserved for mechanoreceptors and electroreceptors. J. Comp. Neurol. 524:1443-1456, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  9. Hair Dyes Resorcinol and Lawsone Reduce Production of Melanin in Melanoma Cells by Tyrosinase Activity Inhibition and Decreasing Tyrosinase and Microphthalmia-Associated Transcription Factor (MITF Expression

    Directory of Open Access Journals (Sweden)

    Shu-Mei Lee

    2015-01-01

    Full Text Available Hair coloring products are one of the most important cosmetics for modern people; there are three major types of hair dyes, including the temporary, semi-permanent and permanent hair dyes. The selected hair dyes (such as ammonium persulfate, sodium persulfate, resorcinol and lawsone are the important components for hair coloring products. Therefore, we analyzed the effects of these compounds on melanogenesis in B16-F10 melanoma cells. The results proved that hair dyes resorcinol and lawsone can reduce the production of melanin. The results also confirmed that resorcinol and lawsone inhibit mushroom and cellular tyrosinase activities in vitro. Resorcinol and lawsone can also downregulate the protein levels of tyrosinase and microphthalmia-associated transcription factor (MITF in B16-F10 cells. Thus, we suggest that frequent use of hair dyes may have the risk of reducing natural melanin production in hair follicles. Moreover, resorcinol and lawsone may also be used as hypopigmenting agents to food, agricultural and cosmetic industry in the future.

  10. Transitory endolymph leakage induced hearing loss and tinnitus: depolarization, biphasic shortening and loss of electromotility of outer hair cells

    Science.gov (United States)

    Zenner, H. P.; Reuter, G.; Zimmermann, U.; Gitter, A. H.; Fermin, C.; LePage, E. L.

    1994-01-01

    There are types of deafness and tinnitus in which ruptures or massive changes in the ionic permeability of the membranes lining the endolymphatic space [e.g., of the reticular lamina (RL)] are believed to allow potassium-rich endolymph to deluge the low [K+] perilymphatic fluid (e.g., in the small spaces of Nuel). This would result in a K+ intoxication of sensory and neural structures. Acute attacks of Meniere's disease have been suggested to be an important example for this event. The present study investigated the effects of transiently elevated [K+] due to the addition of artificial endolymph to the basolateral cell surface of outer hair cells (OHC) in replicating endolymph-induced K+ intoxication of the perilymph in the small spaces of Nuel. The influence of K+ intoxication of the basolateral OHC cell surface on the transduction was then examined. Intoxication resulted in an inhibition of the physiological repolarizing K+ efflux from hair cells. This induced unwanted depolarizations of the hair cells, interfering with mechanoelectrical transduction. A pathological longitudinal OHC shortening was also found, with subsequent compression of the organ of Corti possibly influencing the micromechanics of the mechanically active OHC. Both micromechanical and electrophysiological alterations are proposed to contribute to endolymph leakage induced attacks of deafness and possibly also to tinnitus. Moreover, repeated or long-lasting K+ intoxications of OHC resulted in a chronic and complete loss of OHC motility. This is suggested to be a pathophysiological basis in some patients with chronic hearing loss resulting from Meniere's syndrome.

  11. Discrimination between basal cell carcinoma and hair follicles in skin tissue sections by Raman micro-spectroscopy

    Science.gov (United States)

    Larraona-Puy, M.; Ghita, A.; Zoladek, A.; Perkins, W.; Varma, S.; Leach, I. H.; Koloydenko, A. A.; Williams, H.; Notingher, I.

    2011-05-01

    Skin cancer is the most common human malignancy and basal cell carcinoma (BCC) represents approximately 80% of the non-melanoma cases. Current methods of treatment require histopathological evaluation of the tissues by qualified personnel. However, this method is subjective and in some cases BCC can be confused with other structures in healthy skin, including hair follicles. In this preliminary study, we investigated the potential of Raman micro-spectroscopy (RMS) to discriminate between hair follicles and BCC in skin tissue sections excised during Mohs micrographic surgery (MMS). Imaging and diagnosis of skin sections was automatically generated using ' a priori'-built spectral model based on LDA. This model had 90 ± 9% sensitivity and 85 ± 9% specificity for discrimination of BCC from dermis and epidermis. The model used selected Raman bands corresponding to the largest spectral differences between the Raman spectra of BCC and the normal skin regions, associated mainly with nucleic acids and collagen type I. Raman spectra corresponding to the epidermis regions of the hair follicles were found to be closer to those of healthy epidermis rather than BCC. Comparison between Raman spectral images and the gold standard haematoxylin and eosin (H&E) histopathology diagnosis showed good agreement. Some hair follicle regions were misclassified as BCC; regions corresponded mainly to the outermost layer of hair follicle (basal cells) which are expected to have higher nucleic acid concentration. This preliminary study shows the ability of RMS to distinguish between BCC and other tissue structures associated to healthy skin which can be confused with BCC due to their similar morphology.

  12. The tip-link antigen, a protein associated with the transduction complex of sensory hair cells, is protocadherin-15.

    Science.gov (United States)

    Ahmed, Zubair M; Goodyear, Richard; Riazuddin, Saima; Lagziel, Ayala; Legan, P Kevin; Behra, Martine; Burgess, Shawn M; Lilley, Kathryn S; Wilcox, Edward R; Riazuddin, Sheikh; Griffith, Andrew J; Frolenkov, Gregory I; Belyantseva, Inna A; Richardson, Guy P; Friedman, Thomas B

    2006-06-28

    Sound and acceleration are detected by hair bundles, mechanosensory structures located at the apical pole of hair cells in the inner ear. The different elements of the hair bundle, the stereocilia and a kinocilium, are interconnected by a variety of link types. One of these links, the tip link, connects the top of a shorter stereocilium with the lateral membrane of an adjacent taller stereocilium and may gate the mechanotransducer channel of the hair cell. Mass spectrometric and Western blot analyses identify the tip-link antigen, a hitherto unidentified antigen specifically associated with the tip and kinocilial links of sensory hair bundles in the inner ear and the ciliary calyx of photoreceptors in the eye, as an avian ortholog of human protocadherin-15, a product of the gene for the deaf/blindness Usher syndrome type 1F/DFNB23 locus. Multiple protocadherin-15 transcripts are shown to be expressed in the mouse inner ear, and these define four major isoform classes, two with entirely novel, previously unidentified cytoplasmic domains. Antibodies to the three cytoplasmic domain-containing isoform classes reveal that each has a different spatiotemporal expression pattern in the developing and mature inner ear. Two isoforms are distributed in a manner compatible for association with the tip-link complex. An isoform located at the tips of stereocilia is sensitive to calcium chelation and proteolysis with subtilisin and reappears at the tips of stereocilia as transduction recovers after the removal of calcium chelators. Protocadherin-15 is therefore associated with the tip-link complex and may be an integral component of this structure and/or required for its formation.

  13. The Antigen Presenting Cells Instruct Plasma Cell Differentiation

    Directory of Open Access Journals (Sweden)

    Wei eXu

    2014-01-01

    Full Text Available The professional antigen presenting cells (APCs, including many subsets of dendritic cells and macrophages, not only mediate prompt but nonspecific response against microbes, but also bridge the antigen-specific adaptive immune response through antigen presentation. In the latter, typically activated B cells acquire cognate signals from T helper cells in the germinal center of lymphoid follicles to differentiate into plasma cells, which generate protective antibodies. Recent advances have revealed that many APC subsets provide not only signal 1 (the antigen, but also signal 2 to directly instruct the differentiation process of plasma cells in a T cell-independent manner. Herein, the different signals provided by these APC subsets to direct B cell proliferation, survival, class switching and terminal differentiation are discussed. We furthermore propose that the next generation of vaccines for boosting antibody response could be designed by targeting APCs.

  14. Targeted inactivation of integrin-linked kinase in hair follicle stem cells reveals an important modulatory role in skin repair after injury.

    Science.gov (United States)

    Nakrieko, Kerry-Ann; Rudkouskaya, Alena; Irvine, Timothy S; D'Souza, Sudhir J A; Dagnino, Lina

    2011-07-15

    Integrin-linked kinase (ILK) is key for normal epidermal morphogenesis, but little is known about its role in hair follicle stem cells and epidermal regeneration. Hair follicle stem cells are important contributors to newly formed epidermis following injury. We inactivated the Ilk gene in the keratin 15--expressing stem cell population of the mouse hair follicle bulge. Loss of ILK expression in these cells resulted in impaired cutaneous wound healing, with substantially decreased wound closure rates. ILK-deficient stem cells produced very few descendants that moved toward the epidermal surface and into the advancing epithelium that covers the wound. Furthermore, those few mutant cells that homed in the regenerated epidermis exhibited a reduced residence time. Paradoxically, ILK-deficient bulge stem cells responded to anagen growth signals and contributed to newly regenerated hair follicles during this phase of hair follicle growth. Thus ILK plays an important modulatory role in the normal contribution of hair follicle stem cell progeny to the regenerating epidermis following injury.

  15. Tracking plasma cell differentiation and survival.

    Science.gov (United States)

    Roth, Katrin; Oehme, Laura; Zehentmeier, Sandra; Zhang, Yang; Niesner, Raluca; Hauser, Anja E

    2014-01-01

    Plasma cells play a crucial role for the humoral immune response as they represent the body's factories for antibody production. The differentiation from a B cell into a plasma cell is controlled by a complex transcriptional network and happens within secondary lymphoid organs. Based on their lifetime, two types of antibody secreting cells can be distinguished: Short-lived plasma cells are located in extrafollicular sites of secondary lymphoid organs such as lymph node medullary cords and the splenic red pulp. A fraction of plasmablasts migrate from secondary lymphoid organs to the bone marrow where they can become long-lived plasma cells. Bone marrow plasma cells reside in special microanatomical environments termed survival niches, which provide factors promoting their longevity. Reticular stromal cells producing the chemokine CXCL12, which is known to attract plasmablasts to the bone marrow but also to promote plasma cell survival, play a crucial role in the maintenance of these niches. In addition, hematopoietic cells are contributing to the niches by providing other soluble survival factors. Here, we review the current knowledge on the factors involved in plasma cell differentiation, their localization and migration. We also give an overview on what is known regarding the maintenance of long lived plasma cells in survival niches of the bone marrow. © 2013 International Society for Advancement of Cytometry.

  16. mTOR signaling promotes stem cell activation via counterbalancing BMP-mediated suppression during hair regeneration.

    Science.gov (United States)

    Deng, Zhili; Lei, Xiaohua; Zhang, Xudong; Zhang, Huishan; Liu, Shuang; Chen, Qi; Hu, Huimin; Wang, Xinyue; Ning, Lina; Cao, Yujing; Zhao, Tongbiao; Zhou, Jiaxi; Chen, Ting; Duan, Enkui

    2015-02-01

    Hair follicles (HFs) undergo cycles of degeneration (catagen), rest (telogen), and regeneration (anagen) phases. Anagen begins when the hair follicle stem cells (HFSCs) obtain sufficient activation cues to overcome suppressive signals, mainly the BMP pathway, from their niche cells. Here, we unveil that mTOR complex 1 (mTORC1) signaling is activated in HFSCs, which coincides with the HFSC activation at the telogen-to-anagen transition. By using both an inducible conditional gene targeting strategy and a pharmacological inhibition method to ablate or inhibit mTOR signaling in adult skin epithelium before anagen initiation, we demonstrate that HFs that cannot respond to mTOR signaling display significantly delayed HFSC activation and extended telogen. Unexpectedly, BMP signaling activity is dramatically prolonged in mTOR signaling-deficient HFs. Through both gain- and loss-of-function studies in vitro, we show that mTORC1 signaling negatively affects BMP signaling, which serves as a main mechanism whereby mTORC1 signaling facilitates HFSC activation. Indeed, in vivo suppression of BMP by its antagonist Noggin rescues the HFSC activation defect in mTORC1-null skin. Our findings reveal a critical role for mTOR signaling in regulating stem cell activation through counterbalancing BMP-mediated repression during hair regeneration. © The Author (2015). Published by Oxford University Press on behalf of Journal of Molecular Cell Biology, IBCB, SIBS, CAS. All rights reserved.

  17. Loss of Slc4a1b chloride/bicarbonate exchanger function protects mechanosensory hair cells from aminoglycoside damage in the zebrafish mutant persephone.

    Directory of Open Access Journals (Sweden)

    Dale W Hailey

    Full Text Available Mechanosensory hair cell death is a leading cause of hearing and balance disorders in the human population. Hair cells are remarkably sensitive to environmental insults such as excessive noise and exposure to some otherwise therapeutic drugs. However, individual responses to damaging agents can vary, in part due to genetic differences. We previously carried out a forward genetic screen using the zebrafish lateral line system to identify mutations that alter the response of larval hair cells to the antibiotic neomycin, one of a class of aminoglycoside compounds that cause hair cell death in humans. The persephone mutation confers resistance to aminoglycosides. 5 dpf homozygous persephone mutants are indistinguishable from wild-type siblings, but differ in their retention of lateral line hair cells upon exposure to neomycin. The mutation in persephone maps to the chloride/bicarbonate exchanger slc4a1b and introduces a single Ser-to-Phe substitution in zSlc4a1b. This mutation prevents delivery of the exchanger to the cell surface and abolishes the ability of the protein to import chloride across the plasma membrane. Loss of function of zSlc4a1b reduces hair cell death caused by exposure to the aminoglycosides neomycin, kanamycin, and gentamicin, and the chemotherapeutic drug cisplatin. Pharmacological block of anion transport with the disulfonic stilbene derivatives DIDS and SITS, or exposure to exogenous bicarbonate, also protects hair cells against damage. Both persephone mutant and DIDS-treated wild-type larvae show reduced uptake of labeled aminoglycosides. persephone mutants also show reduced FM1-43 uptake, indicating a potential impact on mechanotransduction-coupled activity in the mutant. We propose that tight regulation of the ionic environment of sensory hair cells, mediated by zSlc4a1b activity, is critical for their sensitivity to aminoglycoside antibiotics.

  18. Resveratrol attenuates CoCl2-induced cochlear hair cell damage through upregulation of Sirtuin1 and NF-κB deacetylation.

    Directory of Open Access Journals (Sweden)

    Ping Wang

    Full Text Available The goals of this study were to investigate the effects of hypoxia on cochlear hair cell damage, and to explore the role of sirtuin1 in hypoxia-induced hair cell damage. Cochlear organotypic cultures from postnatal day 4 rats were used in this study. Hypoxia was induced by treating cochlear explants with CoCl2. Cochlear cultures were treated with CoCl2 alone or in combination with the sirtuin1 activator resveratrol and the sirtuin1 inhibitor sirtinol. Hair cell damage was identified by phalloidin staining and imaged using scanning electron microscopy. RT-PCR and Western blot analyses were used to detect the expression of sirtuin1 and acetylated nuclear factor-κB (NF-κB. Low concentrations of CoCl2 (100-200 μM did not cause an obvious change in the number and morphology of hair cells, whereas higher concentrations of CoCl2 (300-400 μM induced swelling of hair cells, accompanied by cell loss. Increased sirtuin1 expression was induced by CoCl2 at 100 to 200 μM, but not at 400 μM. NF-κB acetylation was significantly increased in explants treated with 400 μM CoCl2. Pretreatment with resveratrol prevented CoCl2-induced hair cell loss and acetylation of NF-κB. The protective effect of resveratrol was significantly reduced by sirtinol. CoCl2 induces hair cell damage in organotypic cochleae cultures. Resveratrol attenuates CoCl2-induced cochlear hair cell damage possibly via activation of sirtuin1, which deacetylates NF-κB.

  19. Bioprinting and Differentiation of Stem Cells

    Directory of Open Access Journals (Sweden)

    Scott A. Irvine

    2016-09-01

    Full Text Available The 3D bioprinting of stem cells directly into scaffolds offers great potential for the development of regenerative therapies; in particular for the fabrication of organ and tissue substitutes. For this to be achieved; the lineage fate of bioprinted stem cell must be controllable. Bioprinting can be neutral; allowing culture conditions to trigger differentiation or alternatively; the technique can be designed to be stimulatory. Such factors as the particular bioprinting technique; bioink polymers; polymer cross-linking mechanism; bioink additives; and mechanical properties are considered. In addition; it is discussed that the stimulation of stem cell differentiation by bioprinting may lead to the remodeling and modification of the scaffold over time matching the concept of 4D bioprinting. The ability to tune bioprinting properties as an approach to fabricate stem cell bearing scaffolds and to also harness the benefits of the cells multipotency is of considerable relevance to the field of biomaterials and bioengineering.

  20. The antigen presenting cells instruct plasma cell differentiation.

    Science.gov (United States)

    Xu, Wei; Banchereau, Jacques

    2014-01-06

    The professional antigen presenting cells (APCs), including many subsets of dendritic cells and macrophages, not only mediate prompt but non-specific response against microbes, but also bridge the antigen-specific adaptive immune response through antigen presentation. In the latter, typically activated B cells acquire cognate signals from T helper cells in the germinal center of lymphoid follicles to differentiate into plasma cells (PCs), which generate protective antibodies. Recent advances have revealed that many APC subsets provide not only "signal 1" (the antigen), but also "signal 2" to directly instruct the differentiation process of PCs in a T-cell-independent manner. Herein, the different signals provided by these APC subsets to direct B cell proliferation, survival, class switching, and terminal differentiation are discussed. We furthermore propose that the next generation of vaccines for boosting antibody response could be designed by targeting APCs.

  1. VEGF induces proliferation of human hair follicle dermal papilla cells through VEGFR-2-mediated activation of ERK

    International Nuclear Information System (INIS)

    Li, Wei; Man, Xiao-Yong; Li, Chun-Ming; Chen, Jia-Qi; Zhou, Jiong; Cai, Sui-Qing; Lu, Zhong-Fa; Zheng, Min

    2012-01-01

    Vascular endothelial growth factor (VEGF) is one of the strongest regulators of physiological and pathological angiogenesis. VEGF receptor 2 (VEGFR-2), the primary receptor for VEGF, is thought to mediate major functional effects of VEGF. Previously, we have localized both VEGF and VEGFR-2 in human hair follicles. In this study, we further defined the expression and roles of VEGFR-2 on human hair follicle dermal papilla (DP) cells. The expression of VEGFR-2 on DP cells was examined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis separately, and localization of VEGFR-2 was defined by immunofluorescence. The effect of VEGF on DP cells was analyzed by MTT assays and specific inhibitors. Finally, the role of VEGF involved in the signaling pathways was investigated by Western blot. RT-PCR and Western blot analysis demonstrated the expression of VEGFR-2 on DP cells. Immunostaining for VEGFR-2 showed strong signal on cultured human DP cells in vitro. Exogenous VEGF 165 stimulated proliferation of DP cells in a dose-dependent manner. Furthermore, this stimulation was blocked by a VEGFR-2 neutralizing antibody (MAB3571) and an ERK inhibitor (PD98059). VEGF 165 -induced phosphorylation of ERK1/2 was abolished by MAB3571 and PD98059, while the phosphorylation of p38, JNK and AKT were not changed by VEGF 165 . Taken together, VEGFR-2 is expressed on primary human hair follicle DP cells and VEGF induces proliferation of DP cells through VEGFR-2/ERK pathway, but not p38, JNK or AKT signaling. -- Highlights: ► We examine the expression of VEGFR-2 on cultured human dermal papilla (DP) cells. ► VEGF 165 stimulated proliferation of human DP cells in a dose-dependent manner. ► This stimulation was through VEGFR-2-mediated activation of ERK.

  2. Localization of Myosin and Actin in the Pelage and Whisker Hair Follicles of Rat

    International Nuclear Information System (INIS)

    Morioka, Kiyokazu; Matsuzaki, Toshiyuki; Takata, Kuniaki

    2006-01-01

    The combined effects of myosin II and actin enable muscle and nonmuscle cells to generate forces required for muscle contraction, cell division, cell migration, cellular morphological changes, the maintenance of cellular tension and polarity, and so on. However, except for the case of muscle contraction, the details are poorly understood. We focus on nonmuscle myosin and actin in the formation and maintenance of hair and skin, which include highly active processes in mammalian life with respect to the cellular proliferation, differentiation, and movement. The localization of nonmuscle myosin II and actin in neonatal rat dorsal skin, mystacial pad, hair follicles, and vibrissal follicles was studied by immunohistochemical technique to provide the basis for the elucidation of the roles of these proteins. Specificities of the antibodies were verified by using samples from the relevant tissues and subjecting them to immunoblotting test prior to morphological analyses. The myosin and actin were abundant and colocalized in the spinous and granular layers but scarce in the basal layer of the dorsal and mystacial epidermis. In hair and vibrissal follicles, nonmuscle myosin and actin were colocalized in the outer root sheath and some hair matrix cells adjoining dermal papillae. In contrast, most areas of the inner root sheath and hair matrix appeared to comprise very small amounts of myosin and actin. Hair shaft may comprise significant myosin during the course of its keratinization. These results suggest that the actin-myosin system plays a part in cell movement, differentiation, protection and other key functions of skin and hair cells

  3. A synthetic prestin reveals protein domains and molecular operation of outer hair cell piezoelectricity.

    Science.gov (United States)

    Schaechinger, Thorsten J; Gorbunov, Dmitry; Halaszovich, Christian R; Moser, Tobias; Kügler, Sebastian; Fakler, Bernd; Oliver, Dominik

    2011-06-24

    Prestin, a transporter-like protein of the SLC26A family, acts as a piezoelectric transducer that mediates the fast electromotility of outer hair cells required for cochlear amplification and auditory acuity in mammals. Non-mammalian prestin orthologues are anion transporters without piezoelectric activity. Here, we generated synthetic prestin (SynPres), a chimera of mammalian and non-mammalian prestin exhibiting both, piezoelectric properties and anion transport. SynPres delineates two distinct domains in the protein's transmembrane core that are necessary and sufficient for generating electromotility and associated non-linear charge movement (NLC). Functional analysis of SynPres showed that the amplitude of NLC and hence electromotility are determined by the transport of monovalent anions. Thus, prestin-mediated electromotility is a dual-step process: transport of anions by an alternate access cycle, followed by an anion-dependent transition generating electromotility. The findings define structural and functional determinants of prestin's piezoelectric activity and indicate that the electromechanical process evolved from the ancestral transport mechanism.

  4. Cochlear Outer-Hair-Cell Power Generation and Viscous Fluid Loss

    Science.gov (United States)

    Wang, Yanli; Steele, Charles R.; Puria, Sunil

    2016-01-01

    Since the discovery of otoacoustic emissions and outer hair cell (OHC) motility, the fundamental question of whether the cochlea produces mechanical power remains controversial. In the present work, direct calculations are performed on power loss due to fluid viscosity and power generated by the OHCs. A three-dimensional box model of the mouse cochlea is used with a feed-forward/feed-backward approximation representing the organ of Corti cytoarchitecture. The model is fit to in vivo basilar membrane motion with one free parameter for the OHCs. The calculations predict that the total power output from the three rows of OHCs can be over three orders of magnitude greater than the acoustic input power at 10 dB sound pressure level (SPL). While previous work shows that the power gain, or the negative damping, diminishes with intensity, we show explicitly based on our model that OHC power output increases and saturates with SPL. The total OHC power output is about 2 pW at 80 dB SPL, with a maximum of about 10 fW per OHC.

  5. Frequency locking in auditory hair cells: Distinguishing between additive and parametric forcing

    Science.gov (United States)

    Edri, Yuval; Bozovic, Dolores; Yochelis, Arik

    2016-10-01

    The auditory system displays remarkable sensitivity and frequency discrimination, attributes shown to rely on an amplification process that involves a mechanical as well as a biochemical response. Models that display proximity to an oscillatory onset (also known as Hopf bifurcation) exhibit a resonant response to distinct frequencies of incoming sound, and can explain many features of the amplification phenomenology. To understand the dynamics of this resonance, frequency locking is examined in a system near the Hopf bifurcation and subject to two types of driving forces: additive and parametric. Derivation of a universal amplitude equation that contains both forcing terms enables a study of their relative impact on the hair cell response. In the parametric case, although the resonant solutions are 1 : 1 frequency locked, they show the coexistence of solutions obeying a phase shift of π, a feature typical of the 2 : 1 resonance. Different characteristics are predicted for the transition from unlocked to locked solutions, leading to smooth or abrupt dynamics in response to different types of forcing. The theoretical framework provides a more realistic model of the auditory system, which incorporates a direct modulation of the internal control parameter by an applied drive. The results presented here can be generalized to many other media, including Faraday waves, chemical reactions, and elastically driven cardiomyocytes, which are known to exhibit resonant behavior.

  6. Clinical and immunologic outcome of patients with cartilage hair hypoplasia after hematopoietic stem cell transplantation.

    Science.gov (United States)

    Bordon, Victoria; Gennery, Andrew R; Slatter, Mary A; Vandecruys, Els; Laureys, Genevieve; Veys, Paul; Qasim, Waseem; Waseem, Qasim; Friedrich, Wilhelm; Wulfraat, Nico M; Scherer, Franziska; Cant, Andrew J; Fischer, Alain; Cavazzana-Calvo, Marina; Cavazanna-Calvo, Marina; Bredius, Robbert G M; Notarangelo, Luigi D; Mazzolari, Evelina; Neven, Benedicte; Güngör, Tayfun; Tayfun, Güngör

    2010-07-08

    Cartilage-hair hypoplasia (CHH) is a rare autosomal recessive disease caused by mutations in the RMRP gene. Beside dwarfism, CHH has a wide spectrum of clinical manifestations including variable grades of combined immunodeficiency, autoimmune complications, and malignancies. Previous reports in single CHH patients with significant immunodeficiencies have demonstrated that allogeneic hematopoietic stem cell transplantation (HSCT) is an effective treatment for the severe immunodeficiency, while growth failure remains unaffected. Because long-term experience in larger cohorts of CHH patients after HSCT is currently unreported, we performed a European collaborative survey reporting on 16 patients with CHH and immunodeficiency who underwent HSCT. Immune dysregulation, lymphoid malignancy, and autoimmunity were important features in this cohort. Thirteen patients were transplanted in early childhood ( approximately 2.5 years). The other 3 patients were transplanted at adolescent age. Of 16 patients, 10 (62.5%) were long-term survivors, with a median follow-up of 7 years. T-lymphocyte numbers and function have normalized, and autoimmunity has resolved in all survivors. HSCT should be considered in CHH patients with severe immunodeficiency/autoimmunity, before the development of severe infections, major organ damage, or malignancy might jeopardize the outcome of HSCT and the quality of life in these patients.

  7. Hyposmotic stimulation-induced nitric oxide production in outer hair cells of the guinea pig cochlea.

    Science.gov (United States)

    Takeda-Nakazawa, Hiroko; Harada, Narinobu; Shen, Jing; Kubo, Nobuo; Zenner, Hans-Peter; Yamashita, Toshio

    2007-08-01

    Nitric oxide (NO) production during hyposmotic stimulation in outer hair cells (OHCs) of the guinea pig cochlea was investigated using the NO sensitive dye DAF-2. Simultaneous measurement of the cell length and NO production showed rapid hyposmotic-induced cell swelling to precede NO production in OHCs. Hyposmotic stimulation failed to induce NO production in the Ca2+-free solution. L-NG-nitroarginine methyl ester (L-NAME), a non-specific NO synthase inhibitor and gadolinium, a stretch-activated channel blocker inhibited the hyposmotic stimulation-induced NO production whereas suramin, a P2 receptor antagonist did not. S-nitroso-N-acetylpenicillamine (SNAP), a NO donor inhibited the hyposmotic stimulation-induced increase in the intracellular Ca2+ concentrations ([Ca2+]i) while L-NAME enhanced it. 1H-[1,2,4]oxadiazole[4,3a]quinoxalin-1-one, an inhibitor of guanylate cyclase and KT5823, an inhibitor of cGMP-dependent protein kinase (PKG) mimicked effects of L-NAME on the Ca2+ response. Transient receptor potential vanilloid 4 (TRPV4), an osmo- and mechanosensitive channel was expressed in the OHCs by means of immunohistochemistry. 4alpha-phorbol 12,13-didecanoate, a TRPV4 synthetic activator, induced NO production in OHCs. These results suggest that hyposmotic stimulation can induce NO production by the [Ca2+]i increase, which is presumably mediated by the activation of TRPV4 in OHCs. NO conversely inhibits the Ca2+ response via the NO-cGMP-PKG pathway by a feedback mechanism.

  8. Schwann cells promote neuronal differentiation of bone marrow ...

    African Journals Online (AJOL)

    Administrator

    2011-04-25

    Apr 25, 2011 ... Bone marrow stromal cells (BMSCs), a type of multipotent stem cell, can differentiate into various types ... induced to differentiate into neuron-like cells when they are ... axonal regeneration and functional reconstruction do not.

  9. Early transcriptional response to aminoglycoside antibiotic suggests alternate pathways leading to apoptosis of sensory hair cells in the mouse inner ear

    Directory of Open Access Journals (Sweden)

    Neil eSegil

    2015-05-01

    Full Text Available Aminoglycoside antibiotics are the drug of choice for treating many bacterial infections, but their administration results in hearing loss in nearly one fourth of the patients who receive them. Several biochemical pathways have been implicated in aminoglycoside antibiotic ototoxicity; however, little is known about how hair cells respond to aminoglycoside antibiotics at the transcriptome level. Here we have investigated the genome-wide response to the aminoglycoside antibiotic gentamicin. Using organotypic cultures of the perinatal organ of Corti, we performed RNA sequencing using cDNA libraries obtained from FACS-purified hair cells. Within 3 hours of gentamicin treatment, the messenger RNA level of more than three thousand genes in hair cells changed significantly. Bioinformatic analysis of these changes highlighted several known signal transduction pathways, including the JNK pathway and the NF-κB pathway, in addition to genes involved in the stress response, apoptosis, cell cycle control, and DNA damage repair. In contrast, only 698 genes, mainly involved in cell cycle and metabolite biosynthetic processes, were significantly affected in the non-hair cell population. The gene expression profiles of hair cells in response to gentamicin share a considerable similarity with those previously observed in gentamicin-induced nephrotoxicity. Our findings suggest that previously observed early responses to gentamicin in hair cells in specific signaling pathways are reflected in changes in gene expression. Additionally, the observed changes in gene expression of cell cycle regulatory genes indicate a disruption of the postmitotic state, which may suggest an alternative pathway regulating gentamicin-induced hair cell death. This work provides a more comprehensive view of aminoglycoside antibiotic ototoxicity, and thus contribute to identifying potential pathways or therapeutic targets to alleviate this important side effect of aminoglycoside

  10. Hydrogels from feather keratin show higher viscoelastic properties and cell proliferation than those from hair and wool keratins.

    Science.gov (United States)

    Esparza, Yussef; Bandara, Nandika; Ullah, Aman; Wu, Jianping

    2018-09-01

    Hydrogel prepared from keratin shows potential applications in tissue engineering. However, the importance of the keratin sources has not been considered. The objectives of this study were to characterize and compare the rheological (storage modulus), physical (porosity, pore size, swelling capacity, and water contact angle) and in vitro cell compatibility of hydrogel scaffolds prepared from various keratin sources. Keratins were characterized by means of their molecular weight, amino acid composition, thermal and conformational properties. Hydrogels from chicken feather keratins demonstrated substantially higher storage modulus (G') than hair and wool keratin hydrogels. However, higher swelling capacity (>3000%) was determined in hair and wool over feather keratin (1500%) hydrogels. Our results suggest that small molecular weight and β-sheet conformation of feather keratin (~10 kDa) facilitated the self-assembly of rigid hydrogels through disulfide bond re-oxidation. Whereas, high molecular weight (10-75 kDa) stretchable α-helix conformation in hair and wool keratins resulted in weaker hydrogels. The cell cultures using fibroblasts showed the highest proliferation rate on chicken feather keratin hydrogel scaffolds. After 15 days of culture, partial breakdown of keratin fibers was observed. Results indicate that stiffer avian keratins can be used to fabricate more mechanically robust biomaterials than mammalian keratins. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Differential white cell count by centrifugal microfluidics.

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, Gregory Jon; Tentori, Augusto M.; Schaff, Ulrich Y.

    2010-07-01

    We present a method for counting white blood cells that is uniquely compatible with centrifugation based microfluidics. Blood is deposited on top of one or more layers of density media within a microfluidic disk. Spinning the disk causes the cell populations within whole blood to settle through the media, reaching an equilibrium based on the density of each cell type. Separation and fluorescence measurement of cell types stained with a DNA dye is demonstrated using this technique. The integrated signal from bands of fluorescent microspheres is shown to be proportional to their initial concentration in suspension. Among the current generation of medical diagnostics are devices based on the principle of centrifuging a CD sized disk functionalized with microfluidics. These portable 'lab on a disk' devices are capable of conducting multiple assays directly from a blood sample, embodied by platforms developed by Gyros, Samsung, and Abaxis. [1,2] However, no centrifugal platform to date includes a differential white blood cell count, which is an important metric complimentary to diagnostic assays. Measuring the differential white blood cell count (the relative fraction of granulocytes, lymphocytes, and monocytes) is a standard medical diagnostic technique useful for identifying sepsis, leukemia, AIDS, radiation exposure, and a host of other conditions that affect the immune system. Several methods exist for measuring the relative white blood cell count including flow cytometry, electrical impedance, and visual identification from a stained drop of blood under a microscope. However, none of these methods is easily incorporated into a centrifugal microfluidic diagnostic platform.

  12. Interactions Between Epidermal Keratinocytes, Dendritic Epidermal T-Cells, and Hair Follicle Stem Cells.

    Science.gov (United States)

    Badarinath, Krithika; Dutta, Abhik; Hegde, Akshay; Pincha, Neha; Gund, Rupali; Jamora, Colin

    2018-06-13

    The interplay of immune cells and stem cells in maintaining skin homeostasis and repair is an exciting new frontier in cutaneous biology. With the growing appreciation of the importance of this new crosstalk comes the requirement of methods to interrogate the molecular underpinnings of these leukocyte-stem cell interactions. Here we describe how a combination of FACS, cellular coculture assays, and conditioned media treatments can be utilized to advance our understanding of this emerging area of intercellular communication between immune cells and stem cells.

  13. Manipulating the cell differentiation through lentiviral vectors.

    Science.gov (United States)

    Coppola, Valeria; Galli, Cesare; Musumeci, Maria; Bonci, Désirée

    2010-01-01

    The manipulation of cell differentiation is important to create new sources for the treatment of degenerative diseases or solve cell depletion after aggressive therapy against cancer. In this chapter, the use of a tissue-specific promoter lentiviral vector to obtain a myocardial pure lineage from murine embryonic stem cells (mES) is described in detail. Since the cardiac isoform of troponin I gene product is not expressed in skeletal or other muscle types, short mouse cardiac troponin proximal promoter is used to drive reporter genes. Cells are infected simultaneously with two lentiviral vectors, the first expressing EGFP to monitor the transduction efficiency, and the other expressing a puromycin resistance gene to select the specific cells of interest. This technical approach describes a method to obtain a pure cardiomyocyte population and can be applied to other lineages of interest.

  14. Cell differentiation: therapeutical challenges in diabetes.

    Science.gov (United States)

    Roche, Enrique; Vicente-Salar, Nestor; Arribas, Maribel; Paredes, Beatriz

    2012-01-01

    Stem cells, derived from either embryonic or adult tissues, are considered to be potential sources of insulin-secreting cells to be transplanted into type 1 and advanced stages of type 2 diabetic patients. Many laboratories have considered this possibility, resulting in a large amount of published protocols, with a wide degree of complexity among them. Our group was the first to report that it was possible to obtain insulin-secreting cells from mouse embryonic stem cells, proving the feasibility of this new challenge. The same observation was immediately reported using human embryonic stem cells. However, the resulting cell product was not properly characterised, affecting the reproducibility of the protocol by other groups. A more elaborated protocol was developed by Lumelsky and co-workers, demonstrating that neuroectodermal cells could be an alternative source for insulin-producing cells. However, the resulting cells of this protocol produced low amounts of the hormone. This aimed other groups to perform key changes in order to improve the insulin content of the resulting cells. Recently, Baetge's group has published a new protocol based on the knowledge accumulated in pancreatic development. In this protocol, human embryonic stem cells were differentiated into islet-like structures through a five step protocol, emulating the key steps during embryonic development of the endocrine pancreas. The final cell product, however, seemed to be in an immature state, thus further improvement is required. Despite this drawback, the protocol represents the culmination of work performed by different groups and offers new research challenges for the investigators in this exciting field. Concerning adult stem cells, the possibility of identifying pancreatic precursors or of reprogramming extrapancreatic derived cells are key possibilities that may circumvent the problems that appear when using embryonic stem cells, such as immune rejection and tumour formation.

  15. In vitro differentiation of mouse embryonic stem cells into functional ...

    African Journals Online (AJOL)

    Studies have shown that embryonic stem (ES) cells can be successfully differentiated into liver cells, which offer the potential unlimited cell source for a variety of end-stage liver disease. In our study, in order to induce mouse ES cells to differentiate into hepatocyte-like cells under chemically defined conditions, ES cells ...

  16. Generation of Induced Pluripotent Stem Cells from Hair Follicle Bulge Neural Crest Stem Cells

    NARCIS (Netherlands)

    Ma, Ming-San; Czepiel, Marcin; Krause, Tina; Schaefer, Karl-Herbert; Boddeke, Erik; Copray, Sjef

    2014-01-01

    Induced pluripotent stem cells (iPSCs) are promising candidates for the study of disease models as well as for tissue engineering purposes. Part of a strategy to develop safe reprogramming technique is reducing the number of exogenous reprogramming factors. Some cells types are more prone to

  17. The epigenomics of embryonic stem cell differentiation.

    Science.gov (United States)

    Kraushaar, Daniel C; Zhao, Keji

    2013-01-01

    Embryonic stem cells (ESCs) possess an open and highly dynamic chromatin landscape, which underlies their plasticity and ultimately maintains ESC pluripotency. The ESC epigenome must not only maintain the transcription of pluripotency-associated genes but must also, through gene priming, facilitate rapid and cell type-specific activation of developmental genes upon lineage commitment. Trans-generational inheritance ensures that the ESC chromatin state is stably transmitted from one generation to the next; yet at the same time, epigenetic marks are highly dynamic, reversible and responsive to extracellular cues. Once committed to differentiation, the ESC epigenome is remodeled and resolves into a more compact chromatin state. A thorough understanding of the role of chromatin modifiers in ESC fate and differentiation will be important if they are to be used for therapeutic purposes. Recent technical advances, particularly in next-generation sequencing technologies, have provided a genome-scale view of epigenetic marks and chromatin modifiers. More affordable and faster sequencing platforms have led to a comprehensive characterization of the ESC epigenome and epigenomes of differentiated cell types. In this review, we summarize and discuss the recent progress that has highlighted the central role of histone modifications, histone variants, DNA methylation and chromatin modifiers in ESC pluripotency and ESC fate. We provide a detailed and comprehensive discussion of genome-wide studies that are pertinent to our understanding of mammalian development.

  18. Proteomic cornerstones of hematopoietic stem cell differentiation

    DEFF Research Database (Denmark)

    Klimmeck, Daniel; Hansson, Jenny; Raffel, Simon

    2012-01-01

    Regenerative tissues such as the skin epidermis, the intestinal mucosa or the hematopoietic system are organized in a hierarchical manner with stem cells building the top of this hierarchy. Somatic stem cells harbor the highest self-renewal activity and generate a series of multipotent progenitors...... which differentiate into lineage committed progenitors and subsequently mature cells. In this report, we applied an in-depth quantitative proteomic approach to analyze and compare the full proteomes of ex vivo isolated and FACS-sorted populations highly enriched for either multipotent hematopoietic stem....../progenitor cells (HSPCs, Lin(neg)Sca-1(+)c-Kit(+)) or myeloid committed precursors (Lin(neg)Sca-1(-)c-Kit(+)). By employing stable isotope dimethyl labeling and high-resolution mass spectrometry, more than 5,000 proteins were quantified. From biological triplicate experiments subjected to rigorous statistical...

  19. Regenerative therapy for vestibular disorders using human induced pluripotent stem cells (iPSCs): neural differentiation of human iPSC-derived neural stem cells after in vitro transplantation into mouse vestibular epithelia.

    Science.gov (United States)

    Taura, Akiko; Nakashima, Noriyuki; Ohnishi, Hiroe; Nakagawa, Takayuki; Funabiki, Kazuo; Ito, Juichi; Omori, Koichi

    2016-10-01

    Vestibular ganglion cells, which convey sense of motion from vestibular hair cells to the brainstem, are known to degenerate with aging and after vestibular neuritis. Thus, regeneration of vestibular ganglion cells is important to aid in the recovery of balance for associated disorders. The present study derived hNSCs from induced pluripotent stem cells (iPSCs) and transplanted these cells into mouse utricle tissues. After a 7-day co-culture period, histological and electrophysiological examinations of transplanted hNSCs were performed. Injected hNSC-derived cells produced elongated axon-like structures within the utricle tissue that made contact with vestibular hair cells. A proportion of hNSC-derived cells showed spontaneous firing activities, similar to those observed in cultured mouse vestibular ganglion cells. However, hNSC-derived cells around the mouse utricle persisted as immature neurons or occasionally differentiated into putative astrocytes. Moreover, electrophysiological examination showed hNSC-derived cells around utricles did not exhibit any obvious spontaneous firing activities. Injected human neural stem cells (hNSCs) showed signs of morphological maturation including reconnection to denervated hair cells and partial physiological maturation, suggesting hNSC-derived cells possibly differentiated into neurons.

  20. Characterization of Wnt and Notch-Responsive Lgr5+ Hair Cell Progenitors in the Striolar Region of the Neonatal Mouse Utricle

    Science.gov (United States)

    You, Dan; Guo, Luo; Li, Wenyan; Sun, Shan; Chen, Yan; Chai, Renjie; Li, Huawei

    2018-01-01

    Dysfunctions in hearing and balance are largely connected with hair cell (HC) loss. Although regeneration of HCs in the adult cochlea does not occur, there is still limited capacity for HC regeneration in the mammalian utricle from a distinct population of supporting cells (SCs). In response to HC damage, these Lgr5+ SCs, especially those in the striolar region, can regenerate HCs. In this study, we isolated Lgr5+ SCs and Plp1+ SCs (which originate from the striolar and extrastriolar regions, respectively) from transgenic mice by flow cytometry so as to compare the properties of these two subsets of SCs. We found that the Lgr5+ progenitors had greater proliferation and HC regeneration ability than the Plp1+ SCs and that the Lgr5+ progenitors responded more strongly to Wnt and Notch signaling than Plp1+ SCs. We then compared the gene expression profiles of the two populations by RNA-Seq and identified several genes that were significantly differentially expressed between the two populations, including genes involved in the cell cycle, transcription and cell signaling pathways. Targeting these genes and pathways might be a potential way to activate HC regeneration. PMID:29760650

  1. Factors affecting the simultaneous determination of copper, lead, cadmium, and zinc concentrations in human head hair using differential pulse anodic stripping voltammetry method

    International Nuclear Information System (INIS)

    Wandiga, S.O.; Jumba, I.O.

    1982-01-01

    Conditions of analysis of copper, lead, cadmium and zinc content in human hair using differential pulse anodic stripping voltammetry (DPASV) and hanging mercury drop electrode (HMDE) have been established. Sample digestion using using the mixture HCI; H 2 O 2 ;HNO 3 in the ratio 2:1:40 by volume gave the best wet-ashing procedure. The peak currents and peak potentials of zinc, cadmium and lead, copper were maximum at pH 6-7 and 1-3 respectively, when excess H 2 O 2 was eliminated with subsequent addition of hydroxyamine hydrochloride. Matrix concentration effects were minimized by digesting weights not exceeding 50 mg per sample. The effect of selenium (IV) was negligible and was ignored. The detection limit of 0.0036 ng/cm 3 for Cd + 2 was obtained while the values for zinc, lead and copper were 0.0230, 0.0287 and 0.0269 ng/cm 3 respectively at the 95% confidence limit. The observed DPASV condition of analysis of these metals are useful for routine determination of the metals in human hair and should complement the conventional flame absorption spectrophotometry method. (author)

  2. Directional differentiation of chicken embryonic stem cells into ...

    African Journals Online (AJOL)

    Jane

    2011-08-01

    Aug 1, 2011 ... In this study, the differentiation potential of chicken ES cells was investigated ... Key words: Chicken embryonic stem cells, in vitro, directional differentiation, .... synthesized by using the Revert Aid first strand cDNA synthesis kit.

  3. The amazing miniorgan: Hair follicle

    Directory of Open Access Journals (Sweden)

    Çiler Çelik Özenci

    2014-06-01

    Full Text Available Hair is a primary characteristic of mammals, and exerts a wide range of functions including thermoregulation, physical protection, sensory activity, and social interactions. The hair shaft consists of terminally differentiated keratinocytes that are produced by the hair follicle. Hair follicle development takes place during fetal skin development and relies on tightly regulated ectodermal–mesodermal interactions. Hair follicles form during embryonic development and, after birth, undergo recurrent cycling of growth (anagen, apoptosis-driven regression (catagen, and relative quiescence (telogen. As a functional mini-organ, the hair follicle develops in an environment with dynamic and alternating changes of diverse molecular signals. Our molecular understanding of hair follicle biology relies heavily on genetically engineered mouse models with abnormalities in hair structure, growth, and/or pigmentation and significant advances have been made toward the identification of key signaling pathways and the regulatory genes involved. In this review, the basic concepts of hair follicle, a mini-complex organ, biology will be presented and its importance in clinical applications will be summarized.

  4. Artificial fish skin of self-powered micro-electromechanical systems hair cells for sensing hydrodynamic flow phenomena.

    Science.gov (United States)

    Asadnia, Mohsen; Kottapalli, Ajay Giri Prakash; Miao, Jianmin; Warkiani, Majid Ebrahimi; Triantafyllou, Michael S

    2015-10-06

    Using biological sensors, aquatic animals like fishes are capable of performing impressive behaviours such as super-manoeuvrability, hydrodynamic flow 'vision' and object localization with a success unmatched by human-engineered technologies. Inspired by the multiple functionalities of the ubiquitous lateral-line sensors of fishes, we developed flexible and surface-mountable arrays of micro-electromechanical systems (MEMS) artificial hair cell flow sensors. This paper reports the development of the MEMS artificial versions of superficial and canal neuromasts and experimental characterization of their unique flow-sensing roles. Our MEMS flow sensors feature a stereolithographically fabricated polymer hair cell mounted on Pb(Zr(0.52)Ti(0.48))O3 micro-diaphragm with floating bottom electrode. Canal-inspired versions are developed by mounting a polymer canal with pores that guide external flows to the hair cells embedded in the canal. Experimental results conducted employing our MEMS artificial superficial neuromasts (SNs) demonstrated a high sensitivity and very low threshold detection limit of 22 mV/(mm s(-1)) and 8.2 µm s(-1), respectively, for an oscillating dipole stimulus vibrating at 35 Hz. Flexible arrays of such superficial sensors were demonstrated to localize an underwater dipole stimulus. Comparative experimental studies revealed a high-pass filtering nature of the canal encapsulated sensors with a cut-off frequency of 10 Hz and a flat frequency response of artificial SNs. Flexible arrays of self-powered, miniaturized, light-weight, low-cost and robust artificial lateral-line systems could enhance the capabilities of underwater vehicles. © 2015 The Author(s).

  5. Elementary properties of Ca(2+) channels and their influence on multivesicular release and phase-locking at auditory hair cell ribbon synapses.

    Science.gov (United States)

    Magistretti, Jacopo; Spaiardi, Paolo; Johnson, Stuart L; Masetto, Sergio

    2015-01-01

    Voltage-gated calcium (Cav1.3) channels in mammalian inner hair cells (IHCs) open in response to sound and the resulting Ca(2+) entry triggers the release of the neurotransmitter glutamate onto afferent terminals. At low to mid sound frequencies cell depolarization follows the sound sinusoid and pulses of transmitter release from the hair cell generate excitatory postsynaptic currents (EPSCs) in the afferent fiber that translate into a phase-locked pattern of action potential activity. The present article summarizes our current understanding on the elementary properties of single IHC Ca(2+) channels, and how these could have functional implications for certain, poorly understood, features of synaptic transmission at auditory hair cell ribbon synapses.

  6. Elementary properties of Ca2+ channels and their influence on multivesicular release and phase-locking at auditory hair cell ribbon synapses

    Science.gov (United States)

    Magistretti, Jacopo; Spaiardi, Paolo; Johnson, Stuart L.; Masetto, Sergio

    2015-01-01

    Voltage-gated calcium (Cav1.3) channels in mammalian inner hair cells (IHCs) open in response to sound and the resulting Ca2+ entry triggers the release of the neurotransmitter glutamate onto afferent terminals. At low to mid sound frequencies cell depolarization follows the sound sinusoid and pulses of transmitter release from the hair cell generate excitatory postsynaptic currents (EPSCs) in the afferent fiber that translate into a phase-locked pattern of action potential activity. The present article summarizes our current understanding on the elementary properties of single IHC Ca2+ channels, and how these could have functional implications for certain, poorly understood, features of synaptic transmission at auditory hair cell ribbon synapses. PMID:25904847

  7. An in vivo root hair assay for determining rates of apoptotic-like programmed cell death in plants

    Directory of Open Access Journals (Sweden)

    Hogg Bridget V

    2011-12-01

    Full Text Available Abstract In Arabidopsis thaliana we demonstrate that dying root hairs provide an easy and rapid in vivo model for the morphological identification of apoptotic-like programmed cell death (AL-PCD in plants. The model described here is transferable between species, can be used to investigate rates of AL-PCD in response to various treatments and to identify modulation of AL-PCD rates in mutant/transgenic plant lines facilitating rapid screening of mutant populations in order to identify genes involved in AL-PCD regulation.

  8. Calcium Regulates Molecular Interactions of Otoferlin with Soluble NSF Attachment Protein Receptor (SNARE) Proteins Required for Hair Cell Exocytosis*

    Science.gov (United States)

    Ramakrishnan, Neeliyath A.; Drescher, Marian J.; Morley, Barbara J.; Kelley, Philip M.; Drescher, Dennis G.

    2014-01-01

    Mutations in otoferlin, a C2 domain-containing ferlin family protein, cause non-syndromic hearing loss in humans (DFNB9 deafness). Furthermore, transmitter secretion of cochlear inner hair cells is compromised in mice lacking otoferlin. In the present study, we show that the C2F domain of otoferlin directly binds calcium (KD = 267 μm) with diminished binding in a pachanga (D1767G) C2F mouse mutation. Calcium was found to differentially regulate binding of otoferlin C2 domains to target SNARE (t-SNARE) proteins and phospholipids. C2D–F domains interact with the syntaxin-1 t-SNARE motif with maximum binding within the range of 20–50 μm Ca2+. At 20 μm Ca2+, the dissociation rate was substantially lower, indicating increased binding (KD = ∼10−9) compared with 0 μm Ca2+ (KD = ∼10−8), suggesting a calcium-mediated stabilization of the C2 domain·t-SNARE complex. C2A and C2B interactions with t-SNAREs were insensitive to calcium. The C2F domain directly binds the t-SNARE SNAP-25 maximally at 100 μm and with reduction at 0 μm Ca2+, a pattern repeated for C2F domain interactions with phosphatidylinositol 4,5-bisphosphate. In contrast, C2F did not bind the vesicle SNARE protein synaptobrevin-1 (VAMP-1). Moreover, an antibody targeting otoferlin immunoprecipitated syntaxin-1 and SNAP-25 but not synaptobrevin-1. As opposed to an increase in binding with increased calcium, interactions between otoferlin C2F domain and intramolecular C2 domains occurred in the absence of calcium, consistent with intra-C2 domain interactions forming a “closed” tertiary structure at low calcium that “opens” as calcium increases. These results suggest a direct role for otoferlin in exocytosis and modulation of calcium-dependent membrane fusion. PMID:24478316

  9. Effects of diurnal temperature difference and gamma radiation on the frequency of somatic cell mutations in the stamen hairs

    International Nuclear Information System (INIS)

    Kim, Jin Kyu; Kim, Won Rok; Kim, Jae Sung; Shin, Hae Shick; Lee, Jeong Joo

    1998-01-01

    This study deals with the effects of diurnal temperature difference (DTD) on somatic cell mutation frequencies in Tradescantia stamen hairs irradiated with radiation. Potted plants of Tradescantia 4430 were irradiated with 0.3, 0.5, 1.0 and 2.0 Gy of gamma radiation. The irradiated plants were maintained under two different experimental conditions; at constant temperature of 20 degree C (DTD0) and at 28 degree C for 14-h day and 8 degree C for 10-h night (DTD20). The somatic cell mutation rate in 0.5 Gy irradiated group showed a big increase on the 6th day and reached a maximum value on the 10th day after irradiation while the rate in the experimental group under the condition of DTD20 started to increase on the 8th day and got to a maximal value on the 14th day postirradiation. In both of the two experiments, the dose-response relationships were clearly linear. The slope of the DTD20 dose-response curve was much steeper than that of the DTD0 one. In conclusion, a great DTD, as one of environmental stresses, enhanced the effectiveness of radiation in the induction of somatic cell mutations and caused a shift of the peak interval of radiation-induced mutations in Tradescantia stamen hairs

  10. Wnt signaling induces differentiation of progenitor cells in organotypic keratinocyte cultures

    Directory of Open Access Journals (Sweden)

    Liu Bob Y

    2007-02-01

    Full Text Available Abstract Background Interfollicular skin develops normally only when the activity of the progenitor cells in the basal layer is counterbalanced by the exit of cells into the suprabasal layers, where they differentiate and cornify to establish barrier function. Distinct stem and progenitor compartments have been demonstrated in hair follicles and sebaceous glands, but there are few data to describe the control of interfollicular progenitor cell activity. Wnt signaling has been shown to be an important growth-inducer of stem cell compartments in skin and many other tissues. Results Here, we test the effect of ectopic Wnt1 expression on the behavior of interfollicular progenitor cells in an organotypic culture model, and find that Wnt1 signaling inhibits their growth and promotes terminal differentiation. Conclusion These results are consistent with the phenotypes reported for transgenic mice engineered to have gain or loss of function of Wnt signaling in skin, which would recommend our culture model as an accurate one for molecular analysis. Since it is known that canonical ligands are expressed in skin, it is likely that this pathway normally regulates the balance of growth and differentiation, and suggests it could be important to pathogenesis.

  11. Hair Transplants

    Science.gov (United States)

    ... for Every Season How to Choose the Best Skin Care Products In This Section Dermatologic Surgery What is dermatologic ... for Every Season How to Choose the Best Skin Care Products Hair Transplants Before (left) and after (right) - top ...

  12. Hair restoration.

    Science.gov (United States)

    Rawnsley, Jeffrey D

    2008-08-01

    The impact of male hair loss as a personal and social marker of aging is tremendous and its persistence as a human concern throughout recorded history places it in the forefront of male concern about the physical signs of aging. Restoration of the frontal hairline has the visual effect of re-establishing facial symmetry and turning back time. Follicular unit transplantation has revolutionized hair restoration, with its focus on redistributing large numbers of genetically stable hair to balding scalp in a natural distribution. Follicular unit hair restoration surgery is a powerful tool for the facial plastic surgeon in male aesthetic facial rejuvenation because it offers high-impact, natural-appearing results with minimal downtime and risk for adverse outcome.

  13. Effects of ultraviolet-visible irradiation in the presence of melanin isolated from human black or red hair upon Ehrlich ascites carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Menon, I.A.; Persad, S.; Ranadive, N.S.; Haberman, H.F.

    1983-07-01

    The present study is an attempt to investigate the possibility that ultraviolet irradiation in the presence of pheomelanin may be more harmful to cells than the irradiation in the presence of eumelanin. The effects of UV-visible irradiation upon Ehrlich ascites carcinoma cells in the presence of the melanin isolated from human black hair (eumelanin) or from red hair (pheomelanin) were investigated. Irradiation of these cells was found to produce cell lysis, as observed by leakage of 51Cr from labeled cells and intracellular lactic dehydrogenase from the cells and decrease in cell viability demonstrated by the trypan blue exclusion test. The three parameters were quantitatively parallel to one another under various experimental conditions, namely different periods of irradiation and irradiation in the presence of different concentrations of melanin. The above effects were more pronounced when the irradiation was carried out in the presence of melanin from red hair than in the presence of black-hair melanin. In the absence of either melanin, the irradiation did not produce any significant effect in cell viability or cell lysis. Irradiation of the cells in the presence of red-hair melanin also decreased the transplantability of these cells. These observations clearly show that irradiation of cells in the presence of pheomelanin could produce cytotoxic effects. The present experimental design may have application in the development of in vitro models for the study of UV radiation-induced cutaneous carcinogenesis. The reactions of pheomelanin may be related to the susceptibility of ''Celtic'' skin to UV radiation-induced skin damage and carcinogenesis.

  14. Neuroendocrine differentiation of prostate cancer cells

    Czech Academy of Sciences Publication Activity Database

    Souček, Karel; Pernicová, Zuzana; Lincová, Eva; Staršíchová, Andrea; Kozubík, Alois

    2008-01-01

    Roč. 102, č. 5 (2008), s. 393 ISSN 0009-2770. [Mezioborové setkání mladých biologů, biochemiků a chemiků. Konference Sigma-Aldrich /8./. 10.06.2008-13.06.2008, Devět skal - Žďárské vrchy] R&D Projects: GA ČR(CZ) GA204/07/0834; GA ČR(CZ) GA310/07/0961 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : neuroendocrine differentiation * prostate cancer * neuroendocrine-like cells Subject RIV: BO - Biophysics

  15. Eye and hair colour, skin type and constitutive skin pigmentation as risk factors for basal cell carcinoma and cutaneous malignant melanoma. A Danish case-control study

    DEFF Research Database (Denmark)

    Lock-Andersen, J; Drzewiecki, K T; Wulf, H C

    1999-01-01

    To assess the importance of hair and eye colour, skin type and constitutive skin pigmentation as risk factors for basal cell carcinoma and cutaneous malignant melanoma in fair-skinned Caucasians, we conducted two identical case-control studies in Denmark. We studied 145 cases with basal cell...

  16. Differentiated cells are more efficient than adult stem cells for cloning by somatic cell nuclear transfer.

    Science.gov (United States)

    Sung, Li-Ying; Gao, Shaorong; Shen, Hongmei; Yu, Hui; Song, Yifang; Smith, Sadie L; Chang, Ching-Chien; Inoue, Kimiko; Kuo, Lynn; Lian, Jin; Li, Ao; Tian, X Cindy; Tuck, David P; Weissman, Sherman M; Yang, Xiangzhong; Cheng, Tao

    2006-11-01

    Since the creation of Dolly via somatic cell nuclear transfer (SCNT), more than a dozen species of mammals have been cloned using this technology. One hypothesis for the limited success of cloning via SCNT (1%-5%) is that the clones are likely to be derived from adult stem cells. Support for this hypothesis comes from the findings that the reproductive cloning efficiency for embryonic stem cells is five to ten times higher than that for somatic cells as donors and that cloned pups cannot be produced directly from cloned embryos derived from differentiated B and T cells or neuronal cells. The question remains as to whether SCNT-derived animal clones can be derived from truly differentiated somatic cells. We tested this hypothesis with mouse hematopoietic cells at different differentiation stages: hematopoietic stem cells, progenitor cells and granulocytes. We found that cloning efficiency increases over the differentiation hierarchy, and terminally differentiated postmitotic granulocytes yield cloned pups with the greatest cloning efficiency.

  17. Probing stem cell differentiation using atomic force microscopy

    International Nuclear Information System (INIS)

    Liang, Xiaobin; Shi, Xuetao; Ostrovidov, Serge; Wu, Hongkai; Nakajima, Ken

    2016-01-01

    Graphical abstract: - Highlights: • Atomic force microscopy (AFM) was developed to probe stem cell differentiation. • The mechanical properties of stem cells and their ECMs can be used to clearly distinguish specific stem cell-differentiated lineages. • AFM is a facile and useful tool for monitoring stem cell differentiation in a non-invasive manner. - Abstract: A real-time method using atomic force microscopy (AFM) was developed to probe stem cell differentiation by measuring the mechanical properties of cells and the extracellular matrix (ECM). The mechanical properties of stem cells and their ECMs can be used to clearly distinguish specific stem cell-differentiated lineages. It is clear that AFM is a facile and useful tool for monitoring the differentiation of stem cells in a non-invasive manner.

  18. Probing stem cell differentiation using atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Xiaobin [Graduate School of Science and Engineering, Tokyo Institute of Technology, Ookayama 2-12-1, Meguro-ku, Tokyo 152-8550 (Japan); Shi, Xuetao, E-mail: mrshixuetao@gmail.com [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Ostrovidov, Serge [WPI-Advanced Institute for Materials Research, Tohoku University, Sendai (Japan); Wu, Hongkai, E-mail: chhkwu@ust.hk [Department of Chemistry & Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China); Nakajima, Ken [Graduate School of Science and Engineering, Tokyo Institute of Technology, Ookayama 2-12-1, Meguro-ku, Tokyo 152-8550 (Japan)

    2016-03-15

    Graphical abstract: - Highlights: • Atomic force microscopy (AFM) was developed to probe stem cell differentiation. • The mechanical properties of stem cells and their ECMs can be used to clearly distinguish specific stem cell-differentiated lineages. • AFM is a facile and useful tool for monitoring stem cell differentiation in a non-invasive manner. - Abstract: A real-time method using atomic force microscopy (AFM) was developed to probe stem cell differentiation by measuring the mechanical properties of cells and the extracellular matrix (ECM). The mechanical properties of stem cells and their ECMs can be used to clearly distinguish specific stem cell-differentiated lineages. It is clear that AFM is a facile and useful tool for monitoring the differentiation of stem cells in a non-invasive manner.

  19. The effect of the inner-hair-cell mediated transduction on the shape of neural tuning curves

    Science.gov (United States)

    Altoè, Alessandro; Pulkki, Ville; Verhulst, Sarah

    2018-05-01

    The inner hair cells of the mammalian cochlea transform the vibrations of their stereocilia into releases of neurotransmitter at the ribbon synapses, thereby controlling the activity of the afferent auditory fibers. The mechanical-to-neural transduction is a highly nonlinear process and it introduces differences between the frequency-tuning of the stereocilia and that of the afferent fibers. Using a computational model of the inner hair cell that is based on in vitro data, we estimated that smaller vibrations of the stereocilia are necessary to drive the afferent fibers above threshold at low (≤0.5 kHz) than at high (≥4 kHz) driving frequencies. In the base of the cochlea, the transduction process affects the low-frequency tails of neural tuning curves. In particular, it introduces differences between the frequency-tuning of the stereocilia and that of the auditory fibers resembling those between basilar membrane velocity and auditory fibers tuning curves in the chinchilla base. For units with a characteristic frequency between 1 and 4 kHz, the transduction process yields shallower neural than stereocilia tuning curves as the characteristic frequency decreases. This study proposes that transduction contributes to the progressive broadening of neural tuning curves from the base to the apex.

  20. No dramatic age-related loss of hair cells and spiral ganglion neurons in Bcl-2 over-expression mice or Bax null mice

    Directory of Open Access Journals (Sweden)

    Ohlemiller Kevin K

    2010-07-01

    Full Text Available Abstract Age-related decline of neuronal function is associated with age-related structural changes. In the central nervous system, age-related decline of cognitive performance is thought to be caused by synaptic loss instead of neuronal loss. However, in the cochlea, age-related loss of hair cells and spiral ganglion neurons (SGNs is consistently observed in a variety of species, including humans. Since age-related loss of these cells is a major contributing factor to presbycusis, it is important to study possible molecular mechanisms underlying this age-related cell death. Previous studies suggested that apoptotic pathways were involved in age-related loss of hair cells and SGNs. In the present study, we examined the role of Bcl-2 gene in age-related hearing loss. In one transgenic mouse line over-expressing human Bcl-2, there were no significant differences between transgenic mice and wild type littermate controls in their hearing thresholds during aging. Histological analysis of the hair cells and SGNs showed no significant conservation of these cells in transgenic animals compared to the wild type controls during aging. These data suggest that Bcl-2 overexpression has no significant effect on age-related loss of hair cells and SGNs. We also found no delay of age-related hearing loss in mice lacking Bax gene. These findings suggest that age-related hearing loss is not through an apoptotic pathway involving key members of Bcl-2 family.

  1. Association of intracellular and synaptic organization in cochlear inner hair cells revealed by 3D electron microscopy.

    Science.gov (United States)

    Bullen, Anwen; West, Timothy; Moores, Carolyn; Ashmore, Jonathan; Fleck, Roland A; MacLellan-Gibson, Kirsty; Forge, Andrew

    2015-07-15

    The ways in which cell architecture is modelled to meet cell function is a poorly understood facet of cell biology. To address this question, we have studied the cytoarchitecture of a cell with highly specialised organisation, the cochlear inner hair cell (IHC), using multiple hierarchies of three-dimensional (3D) electron microscopy analyses. We show that synaptic terminal distribution on the IHC surface correlates with cell shape, and the distribution of a highly organised network of membranes and mitochondria encompassing the infranuclear region of the cell. This network is juxtaposed to a population of small vesicles, which represents a potential new source of neurotransmitter vesicles for replenishment of the synapses. Structural linkages between organelles that underlie this organisation were identified by high-resolution imaging. Taken together, these results describe a cell-encompassing network of membranes and mitochondria present in IHCs that support efficient coding and transmission of auditory signals. Such techniques also have the potential for clarifying functionally specialised cytoarchitecture of other cell types. © 2015. Published by The Company of Biologists Ltd.

  2. Reduced systemic toxicity and preserved vestibular toxicity following co-treatment with nitriles and CYP2E1 inhibitors: a mouse model for hair cell loss.

    Science.gov (United States)

    Saldaña-Ruíz, Sandra; Boadas-Vaello, Pere; Sedó-Cabezón, Lara; Llorens, Jordi

    2013-10-01

    Several nitriles, including allylnitrile and cis-crotononitrile, have been shown to be ototoxic and cause hair cell degeneration in the auditory and vestibular sensory epithelia of mice. However, these nitriles can also be lethal due in large part to the microsomal metabolic release of cyanide, which is mostly dependent on the activity of the 2E1 isoform of the cytochrome P450 (CYP2E1). In this study, we co-administered mice with a nitrile and, to reduce their lethal effects, a selective CYP2E1 inhibitor: diallylsulfide (DAS) or trans-1,2-dichloroethylene (TDCE). Both in female 129S1/SvImJ (129S1) mice co-treated with DAS and cis-crotononitrile and in male RjOrl:Swiss/CD-1 (Swiss) mice co-treated with TDCE and allylnitrile, the nitrile caused a dose-dependent loss of vestibular function, as assessed by a specific behavioral test battery, and of hair cells, as assessed by hair bundle counts using scanning electron microscopy. In the experiments, the CYP2E1 inhibitors provided significant protection against the lethal effects of the nitriles and did not diminish the vestibular toxicity as assessed by behavioral effects in comparison to animals receiving no inhibitor. Additional experiments using a single dose of allylnitrile demonstrated that TDCE does not cause hair cell loss on its own and does not modify the vestibular toxicity of the nitrile in either male or female 129S1 mice. In all the experiments, high vestibular dysfunction scores in the behavioral test battery predicted extensive to complete loss of hair cells in the utricles. This provides a means of selecting animals for subsequent studies of vestibular hair cell regeneration or replacement.

  3. Unique B cell differentiation profile in tolerant kidney transplant patients.

    Science.gov (United States)

    Chesneau, M; Pallier, A; Braza, F; Lacombe, G; Le Gallou, S; Baron, D; Giral, M; Danger, R; Guerif, P; Aubert-Wastiaux, H; Néel, A; Michel, L; Laplaud, D-A; Degauque, N; Soulillou, J-P; Tarte, K; Brouard, S

    2014-01-01

    Operationally tolerant patients (TOL) display a higher number of blood B cells and transcriptional B cell signature. As they rarely develop an allo-immune response, they could display an abnormal B cell differentiation. We used an in vitro culture system to explore T-dependent differentiation of B cells into plasma cells. B cell phenotype, apoptosis, proliferation, cytokine, immunoglobulin production and markers of differentiation were followed in blood of these patients. Tolerant recipients show a higher frequency of CD20(+) CD24(hi) CD38(hi) transitional and CD20(+) CD38(lo) CD24(lo) naïve B cells compared to patients with stable graft function, correlating with a decreased frequency of CD20(-) CD38(+) CD138(+) differentiated plasma cells, suggestive of abnormal B cell differentiation. B cells from TOL proliferate normally but produce more IL-10. In addition, B cells from tolerant recipients exhibit a defective expression of factors of the end step of differentiation into plasma cells and show a higher propensity for cell death apoptosis compared to patients with stable graft function. This in vitro profile is consistent with down-regulation of B cell differentiation genes and anti-apoptotic B cell genes in these patients in vivo. These data suggest that a balance between B cells producing IL-10 and a deficiency in plasma cells may encourage an environment favorable to the tolerance maintenance. © Copyright 2013 The American Society of Transplantation and the American Society of Transplant Surgeons.

  4. Removing Hair Safely

    Science.gov (United States)

    ... For Consumers Home For Consumers Consumer Updates Removing Hair Safely Share Tweet Linkedin Pin it More sharing ... related to common methods of hair removal. Laser Hair Removal In this method, a laser destroys hair ...

  5. Hair Loss (Alopecia)

    Science.gov (United States)

    ... care Kids’ zone Video library Find a dermatologist Hair loss Overview Hereditary hair loss: Millions of men ... of hair loss can often be successfully treated. Hair loss: Overview Also called alopecia (al-o-PEE- ...

  6. In vitro differentiation of mouse embryonic stem cells into functional ...

    African Journals Online (AJOL)

    Jane

    2011-08-22

    Aug 22, 2011 ... hepatocyte transplantation therapy and toxicity screening in drug discovery. Key words: Embryonic stem cells, hepatic-like cells, in vitro differentiation, sodium butyrate, ... from embryonic stem (ES) cell or induced pluripotent.

  7. Six1 is essential for differentiation and patterning of the mammalian auditory sensory epithelium.

    Directory of Open Access Journals (Sweden)

    Ting Zhang

    2017-09-01

    Full Text Available The organ of Corti in the cochlea is a two-cell layered epithelium: one cell layer of mechanosensory hair cells that align into one row of inner and three rows of outer hair cells interdigitated with one cell layer of underlying supporting cells along the entire length of the cochlear spiral. These two types of epithelial cells are derived from common precursors in the four- to five-cell layered primordium and acquire functionally important shapes during terminal differentiation through the thinning process and convergent extension. Here, we have examined the role of Six1 in the establishment of the auditory sensory epithelium. Our data show that prior to terminal differentiation of the precursor cells, deletion of Six1 leads to formation of only a few hair cells and defective patterning of the sensory epithelium. Previous studies have suggested that downregulation of Sox2 expression in differentiating hair cells must occur after Atoh1 mRNA activation in order to allow Atoh1 protein accumulation due to antagonistic effects between Atoh1 and Sox2. Our analysis indicates that downregulation of Sox2 in the differentiating hair cells depends on Six1 activity. Furthermore, we found that Six1 is required for the maintenance of Fgf8 expression and dynamic distribution of N-cadherin and E-cadherin in the organ of Corti during differentiation. Together, our analyses uncover essential roles of Six1 in hair cell differentiation and formation of the organ of Corti in the mammalian cochlea.

  8. [CONDITIONS OF SYNOVIAL MESENCHYMAL STEM CELLS DIFFERENTIATING INTO FIBROCARTILAGE CELLS].

    Science.gov (United States)

    Fu, Peiliang; Cong, Ruijun; Chen, Song; Zhang, Lei; Ding, Zheru; Zhou, Qi; Li, Lintao; Xu, Zhenyu; Wu, Yuli; Wu, Haishan

    2015-01-01

    To explore the conditions of synovial derived mesenchymal stem cells (SMSCs) differentiating into the fibrocartilage cells by using the orthogonal experiment. The synovium was harvested from 5 adult New Zealand white rabbits, and SMSCs were separated by adherence method. The flow cytometry and multi-directional differentiation method were used to identify the SMSCs. The conditions were found from the preliminary experiment and literature review. The missing test was carried out to screen the conditions and then 12 conditions were used for the orthogonal experiment, including transforming growth factor β1 (TGF-β1), bone morphogenic protein 2 (BMP-2), dexamethasone (DEX), proline, ascorbic acid (ASA), pyruvic acid, insulin + transferrin + selenious acid pre-mixed solution (ITS), bovin serum albumin (BSA), basic fibroblast growth factor (bFGF), intermittent hydraulic pressure (IHP), bone morphogenic protein 7 (BMP-7), and insulin-like growth factor (IGF). The L60 (212) orthogonal experiment was designed using the SPSS 18.0 with 2 level conditions and the cells were induced to differentiate on the small intestinal submucosa (SIS)-3D scaffold. The CD151+/CD44+ cells were detected with the flow cytometry and then the differentiation rate was recorded. The immumohistochemical staining, cellular morphology, toluidine blue staining, and semi-quantitative RT-PCR examination for the gene expressions of sex determining region Y (SRY)-box 9 gene (Sox9), aggrecan gene (AGN), collagen type I gene (Col I), collagen type II gene (Col II), collagen type IX gene (Col IX) were used for result confirmation. The differentiation rate was calculated as the product of CD151/CD44+ cells and cells with Col I high expression. The grow curve was detected with the DNA abundance using the PicoGreen Assay. The visual observation and the variances analysis among the variable were used to evaluate the result of the orthogonal experiment, 1 level interaction was considered. The q-test and the

  9. Nanomaterials modulate stem cell differentiation: biological interaction and underlying mechanisms.

    Science.gov (United States)

    Wei, Min; Li, Song; Le, Weidong

    2017-10-25

    Stem cells are unspecialized cells that have the potential for self-renewal and differentiation into more specialized cell types. The chemical and physical properties of surrounding microenvironment contribute to the growth and differentiation of stem cells and consequently play crucial roles in the regulation of stem cells' fate. Nanomaterials hold great promise in biological and biomedical fields owing to their unique properties, such as controllable particle size, facile synthesis, large surface-to-volume ratio, tunable surface chemistry, and biocompatibility. Over the recent years, accumulating evidence has shown that nanomaterials can facilitate stem cell proliferation and differentiation, and great effort is undertaken to explore their possible modulating manners and mechanisms on stem cell differentiation. In present review, we summarize recent progress in the regulating potential of various nanomaterials on stem cell differentiation and discuss the possible cell uptake, biological interaction and underlying mechanisms.

  10. Transplantation and differentiation of donor cells in the cloned pigs

    International Nuclear Information System (INIS)

    Shimada, Arata; Tomii, Ryo; Kano, Koichiro; Nagashima, Hiroshi

    2006-01-01

    The application of nuclear transfer technology is an interesting approach to investigate stem and progenitor cell transplantation therapy. If stem cells are used as a nuclear donor, donor cells can engraft into cloned animals without histocompatible problems. However, it is still uncertain whether donor cells can engraft to cloned animal and differentiate in vivo. To address this problem, we transplanted donor cells to dermal tissues of cloned pigs developed by using preadipocytes as donor cells. Preadipocytes are adipocytic progenitor which can differentiate to mature adipocytes in vitro. We showed that the donor preadipocytes were successfully transplanted into the cloned pigs without immune rejection and they differentiated into mature adipocytes in vivo 3 weeks after transplantation. In contrast, allogenic control preadipocytes, which can differentiate in vitro, did not differentiate in vivo. These results indicate that donor progenitor cells can differentiate in cloned animal

  11. Hair follicle proteoglycans

    DEFF Research Database (Denmark)

    Couchman, J R

    1993-01-01

    that are present in the epithelial and stromal compartments of hair follicles. However, the transmembrane proteoglycan syndecan may be important in follicle morphogenesis, both with respect to the epithelium and dermal papilla cells. Syndecan may possess both heparan and chondroitin sulfate chains, interacts...... basement membranes, including those surrounding the epithelial compartment of hair follicles. Additionally, and quite unlike the dermis, the dermal papilla is enriched in basement-membrane components, especially a chondroitin 6-sulfate-containing proteoglycan, BM-CSPG. The function of this proteoglycan...... is not known, but developmental studies indicate that it may have a role in stabilizing basement membranes. In the hair cycle, BM-CSPG decreases through catagen and is virtually absent from the telogen papilla. One or more heparan sulfate proteoglycans, including perlecan, are also present in papilla...

  12. Oligodendrocyte differentiation and implantation : new insights for remyelinating cell therapy

    NARCIS (Netherlands)

    Sher, Falak; Balasubramaniyan, Veerakumar; Boddeke, Erik; Copray, Sjef

    2008-01-01

    Purpose of review Recent research on oligodendrocyte development has yielded new insights on the involvement of morphogens and differentiation factors in oligodendrogenesis. This knowledge has improved strategies to control neural stem cell-derived oligodendrocyte differentiation and functional

  13. The goya mouse mutant reveals distinct newly identified roles for MAP3K1 in the development and survival of cochlear sensory hair cells

    Directory of Open Access Journals (Sweden)

    Andrew Parker

    2015-12-01

    Full Text Available Mitogen-activated protein kinase, MAP3K1, plays an important role in a number of cellular processes, including epithelial migration during eye organogenesis. In addition, studies in keratinocytes indicate that MAP3K1 signalling through JNK is important for actin stress fibre formation and cell migration. However, MAP3K1 can also act independently of JNK in the regulation of cell proliferation and apoptosis. We have identified a mouse mutant, goya, which exhibits the eyes-open-at-birth and microphthalmia phenotypes. In addition, these mice also have hearing loss. The goya mice carry a splice site mutation in the Map3k1 gene. We show that goya and kinase-deficient Map3k1 homozygotes initially develop supernumerary cochlear outer hair cells (OHCs that subsequently degenerate, and a progressive profound hearing loss is observed by 9 weeks of age. Heterozygote mice also develop supernumerary OHCs, but no cellular degeneration or hearing loss is observed. MAP3K1 is expressed in a number of inner-ear cell types, including outer and inner hair cells, stria vascularis and spiral ganglion. Investigation of targets downstream of MAP3K1 identified an increase in p38 phosphorylation (Thr180/Tyr182 in multiple cochlear tissues. We also show that the extra OHCs do not arise from aberrant control of proliferation via p27KIP1. The identification of the goya mutant reveals a signalling molecule involved with hair-cell development and survival. Mammalian hair cells do not have the ability to regenerate after damage, which can lead to irreversible sensorineural hearing loss. Given the observed goya phenotype, and the many diverse cellular processes that MAP3K1 is known to act upon, further investigation of this model might help to elaborate upon the mechanisms underlying sensory hair cell specification, and pathways important for their survival. In addition, MAP3K1 is revealed as a new candidate gene for human sensorineural hearing loss.

  14. Genetic DNA profile in urine and hair follicles from patients who have undergone allogeneic hematopoietic stem cell transplantation.

    Science.gov (United States)

    Santurtún, Ana; Riancho, José A; Santurtún, Maite; Richard, Carlos; Colorado, M Mercedes; García Unzueta, Mayte; Zarrabeitia, María T

    2017-09-01

    Biological samples from patients who have undergone allogeneic hematopoietic stem cell transplantation (HSCT) constitute a challenge for individual identification. In this study we analyzed the genetic profiles (by the amplification of 15 autosomic STRs) of HSCT patients found in different types of samples (blood, hair and urine) that may be the source of DNA in civil or criminal forensic cases. Our results show that while in hair follicles the donor component was not detected in any patient, thus being a reliable source of biological material for forensic identification, mixed chimerism was detected in urine samples from all patient, and no correlation was found between the time elapsed from the transplant and the percentage of chimerism. These results certainly have practical implications if the urine is being considered as a source of DNA for identification purposes in HSTC patients. Moreover, taking into consideration that chimerism was found not only in patients with leukocyturia (given the hematopoietic origin of leukocytes, this was expected), but also in those without observable leukocytes in the sediment, we conclude that an alternative source or sources of donor DNA must be implicated. Copyright © 2017 The Chartered Society of Forensic Sciences. Published by Elsevier B.V. All rights reserved.

  15. Wnt-10b, uniquely among Wnts, promotes epithelial differentiation and shaft growth

    International Nuclear Information System (INIS)

    Ouji, Yukiteru; Yoshikawa, Masahide; Moriya, Kei; Nishiofuku, Mariko; Matsuda, Ryosuke; Ishizaka, Shigeaki

    2008-01-01

    Although Wnts are expressed in hair follicles throughout life from embryo to adult, and considered to be critical for their development and maturation, their roles remain largely unknown. In the present study, we investigated the effects of Wnts (Wnt-3a, Wnt-5a, Wnt-10b, and Wnt-11) on epithelial cell differentiation using adult mouse-derived primary skin epithelial cell (MPSEC) cultures and hair growth using hair follicle organ cultures. Only Wnt-10b showed evident promotion of epithelial cell differentiation and hair shaft growth, in contrast to Wnt-3a, 5a, and 11. Our results suggest that Wnt-10b is unique and plays an important role in differentiation of epithelial cells in the hair follicle

  16. Downregulation of rRNA transcription triggers cell differentiation.

    Directory of Open Access Journals (Sweden)

    Yuki Hayashi

    Full Text Available Responding to various stimuli is indispensable for the maintenance of homeostasis. The downregulation of ribosomal RNA (rRNA transcription is one of the mechanisms involved in the response to stimuli by various cellular processes, such as cell cycle arrest and apoptosis. Cell differentiation is caused by intra- and extracellular stimuli and is associated with the downregulation of rRNA transcription as well as reduced cell growth. The downregulation of rRNA transcription during differentiation is considered to contribute to reduced cell growth. However, the downregulation of rRNA transcription can induce various cellular processes; therefore, it may positively regulate cell differentiation. To test this possibility, we specifically downregulated rRNA transcription using actinomycin D or a siRNA for Pol I-specific transcription factor IA (TIF-IA in HL-60 and THP-1 cells, both of which have differentiation potential. The inhibition of rRNA transcription induced cell differentiation in both cell lines, which was demonstrated by the expression of the common differentiation marker CD11b. Furthermore, TIF-IA knockdown in an ex vivo culture of mouse hematopoietic stem cells increased the percentage of myeloid cells and reduced the percentage of immature cells. We also evaluated whether differentiation was induced via the inhibition of cell cycle progression because rRNA transcription is tightly coupled to cell growth. We found that cell cycle arrest without affecting rRNA transcription did not induce differentiation. To the best of our knowledge, our results demonstrate the first time that the downregulation of rRNA levels could be a trigger for the induction of differentiation in mammalian cells. Furthermore, this phenomenon was not simply a reflection of cell cycle arrest. Our results provide a novel insight into the relationship between rRNA transcription and cell differentiation.

  17. Human invariant NKT cell subsets differentially promote differentiation, antibody production, and T cell stimulation by B cells in vitro.

    OpenAIRE

    O'REILLY, VINCENT

    2013-01-01

    PUBLISHED Invariant NK T (iNKT) cells can provide help for B cell activation and Ab production. Because B cells are also capable of cytokine production, Ag presentation, and T cell activation, we hypothesized that iNKT cells will also influence these activities. Furthermore, subsets of iNKT cells based on CD4 and CD8 expression that have distinct functional activities may differentially affect B cell functions. We investigated the effects of coculturing expanded human CD4(+), CD8α(+), and ...

  18. Directional differentiation of chicken embryonic stem cells into ...

    African Journals Online (AJOL)

    Chicken embryonic stem (ES) cells are useful for producing transgenic chickens and preserving genetic material in avian species. In this study, the differentiation potential of chicken ES cells was investigated in vitro. Chicken ES cells were differentiated into osteoblasts cultured for 15 to 21 days in the induction media ...

  19. Root hair defective4 encodes a phosphatidylinositol-4-phosphate phosphatase required for proper root hair development in Arabidopsis thaliana

    NARCIS (Netherlands)

    Thole, J.M.; Vermeer, J.E.M.; Zhang, Y.; Gadella, Th.W.J.; Nielsen, E.

    2008-01-01

    Polarized expansion of root hair cells in Arabidopsis thaliana is improperly controlled in root hair-defective rhd4-1 mutant plants, resulting in root hairs that are shorter and randomly form bulges along their length. Using time-lapse fluorescence microscopy in rhd4-1 root hairs, we analyzed

  20. Primitive human hematopoietic cells give rise to differentially specified daughter cells upon their initial cell division.

    NARCIS (Netherlands)

    Giebel, B.; Zhang, T.; Beckmann, J.; Spanholtz, J.; Wernet, P.; Ho, A.; Punzel, M.

    2006-01-01

    It is often predicted that stem cells divide asymmetrically, creating a daughter cell that maintains the stem-cell capacity, and 1 daughter cell committed to differentiation. While asymmetric stem-cell divisions have been proven to occur in model organisms (eg, in Drosophila), it remains illusive

  1. Ion channel regulation of the dynamical instability of the resting membrane potential in saccular hair cells of the green frog (Rana esculenta)

    NARCIS (Netherlands)

    Jorgensen, F; Kroese, ABA

    2005-01-01

    Aims: We investigated the ion channel regulation of the resting membrane potential of hair cells with the aim to determine if the resting membrane potential is poised close to instability and thereby a potential cause of the spontaneous afferent spike activity. Methods: The ionic mechanism and the

  2. Single-channel L-type Ca2+ currents in chicken embryo semicircular canal type I and type II hair cells.

    Science.gov (United States)

    Zampini, Valeria; Valli, Paolo; Zucca, Giampiero; Masetto, Sergio

    2006-08-01

    Few data are available concerning single Ca channel properties in inner ear hair cells and particularly none in vestibular type I hair cells. By using the cell-attached configuration of the patch-clamp technique in combination with the semicircular canal crista slice preparation, we determined the elementary properties of voltage-dependent Ca channels in chicken embryo type I and type II hair cells. The pipette solutions included Bay K 8644. With 70 mM Ba(2+) in the patch pipette, Ca channel activity appeared as very brief openings at -60 mV. Ca channel properties were found to be similar in type I and type II hair cells; therefore data were pooled. The mean inward current amplitude was -1.3 +/- 0.1 (SD) pA at - 30 mV (n = 16). The average slope conductance was 21 pS (n = 20). With 5 mM Ba(2+) in the patch pipette, very brief openings were already detectable at -80 mV. The mean inward current amplitude was -0.7 +/- 0.2 pA at -40 mV (n = 9). The average slope conductance was 11 pS (n = 9). The mean open time and the open probability increased significantly with depolarization. Ca channel activity was still present and unaffected when omega-agatoxin IVA (2 microM) and omega-conotoxin GVIA (3.2 microM) were added to the pipette solution. Our results show that types I and II hair cells express L-type Ca channels with similar properties. Moreover, they suggest that in vivo Ca(2+) influx might occur at membrane voltages more negative than -60 mV.

  3. Symbiotic Cell Differentiation and Cooperative Growth in Multicellular Aggregates.

    Directory of Open Access Journals (Sweden)

    Jumpei F Yamagishi

    2016-10-01

    Full Text Available As cells grow and divide under a given environment, they become crowded and resources are limited, as seen in bacterial biofilms and multicellular aggregates. These cells often show strong interactions through exchanging chemicals, as evident in quorum sensing, to achieve mutualism and division of labor. Here, to achieve stable division of labor, three characteristics are required. First, isogenous cells differentiate into several types. Second, this aggregate of distinct cell types shows better growth than that of isolated cells without interaction and differentiation, by achieving division of labor. Third, this cell aggregate is robust with respect to the number distribution of differentiated cell types. Indeed, theoretical studies have thus far considered how such cooperation is achieved when the ability of cell differentiation is presumed. Here, we address how cells acquire the ability of cell differentiation and division of labor simultaneously, which is also connected with the robustness of a cell society. For this purpose, we developed a dynamical-systems model of cells consisting of chemical components with intracellular catalytic reaction dynamics. The reactions convert external nutrients into internal components for cellular growth, and the divided cells interact through chemical diffusion. We found that cells sharing an identical catalytic network spontaneously differentiate via induction from cell-cell interactions, and then achieve division of labor, enabling a higher growth rate than that in the unicellular case. This symbiotic differentiation emerged for a class of reaction networks under the condition of nutrient limitation and strong cell-cell interactions. Then, robustness in the cell type distribution was achieved, while instability of collective growth could emerge even among the cooperative cells when the internal reserves of products were dominant. The present mechanism is simple and general as a natural consequence of

  4. Non-genetic heterogeneity, criticality and cell differentiation.

    Science.gov (United States)

    Pal, Mainak; Ghosh, Sayantari; Bose, Indrani

    2014-11-27

    The different cell types in a living organism acquire their identity through the process of cell differentiation in which multipotent progenitor cells differentiate into distinct cell types. Experimental evidence and analysis of large-scale microarray data establish the key role played by a two-gene motif in cell differentiation in a number of cell systems. The two genes express transcription factors which repress each other's expression and autoactivate their own production. A number of theoretical models have recently been proposed based on the two-gene motif to provide a physical understanding of how cell differentiation occurs. In this paper, we study a simple model of cell differentiation which assumes no cooperativity in the regulation of gene expression by the transcription factors. The latter repress each other's activity directly through DNA binding and indirectly through the formation of heterodimers. We specifically investigate how deterministic processes combined with stochasticity contribute in bringing about cell differentiation. The deterministic dynamics of our model give rise to a supercritical pitchfork bifurcation from an undifferentiated stable steady state to two differentiated stable steady states. The stochastic dynamics of our model are studied using the approaches based on the Langevin equations and the linear noise approximation. The simulation results provide a new physical understanding of recent experimental observations. We further propose experimental measurements of quantities like the variance and the lag-1 autocorrelation function in protein fluctuations as the early signatures of an approaching bifurcation point in the cell differentiation process.

  5. A point mutation in the hair cell nicotinic cholinergic receptor prolongs cochlear inhibition and enhances noise protection.

    Directory of Open Access Journals (Sweden)

    Julian Taranda

    2009-01-01

    Full Text Available The transduction of sound in the auditory periphery, the cochlea, is inhibited by efferent cholinergic neurons projecting from the brainstem and synapsing directly on mechanosensory hair cells. One fundamental question in auditory neuroscience is what role(s this feedback plays in our ability to hear. In the present study, we have engineered a genetically modified mouse model in which the magnitude and duration of efferent cholinergic effects are increased, and we assess the consequences of this manipulation on cochlear function. We generated the Chrna9L9'T line of knockin mice with a threonine for leucine change (L9'T at position 9' of the second transmembrane domain of the alpha9 nicotinic cholinergic subunit, rendering alpha9-containing receptors that were hypersensitive to acetylcholine and had slower desensitization kinetics. The Chrna9L9'T allele produced a 3-fold prolongation of efferent synaptic currents in vitro. In vivo, Chrna9L9'T mice had baseline elevation of cochlear thresholds and efferent-mediated inhibition of cochlear responses was dramatically enhanced and lengthened: both effects were reversed by strychnine blockade of the alpha9alpha10 hair cell nicotinic receptor. Importantly, relative to their wild-type littermates, Chrna9(L9'T/L9'T mice showed less permanent hearing loss following exposure to intense noise. Thus, a point mutation designed to alter alpha9alpha10 receptor gating has provided an animal model in which not only is efferent inhibition more powerful, but also one in which sound-induced hearing loss can be restrained, indicating the ability of efferent feedback to ameliorate sound trauma.

  6. Reduced sensory stimulation alters the molecular make-up of glutamatergic hair cell synapses in the developing cochlea.

    Science.gov (United States)

    Barclay, M; Constable, R; James, N R; Thorne, P R; Montgomery, J M

    2016-06-14

    Neural activity during early development is known to alter innervation pathways in the central and peripheral nervous systems. We sought to examine how reduced sound-induced sensory activity in the cochlea affected the consolidation of glutamatergic synapses between inner hair cells (IHC) and the primary auditory neurons as these synapses play a primary role in transmitting sound information to the brain. A unilateral conductive hearing loss was induced prior to the onset of sound-mediated stimulation of the sensory hair cells, by rupturing the tympanic membrane and dislocating the auditory ossicles in the left ear of P11 mice. Auditory brainstem responses at P15 and P21 showed a 40-50-dB increase in thresholds for frequencies 8-32kHz in the dislocated ear relative to the control ear. Immunohistochemistry and confocal microscopy were subsequently used to examine the effect of this attenuation of sound stimulation on the expression of RIBEYE, which comprises the presynaptic ribbons, Shank-1, a postsynaptic scaffolding protein, and the GluA2/3 and 4 subunits of postsynaptic AMPA receptors. Our results show that dislocation did not alter the number of pre- or postsynaptic protein puncta. However, dislocation did increase the size of RIBEYE, GluA4, GluA2/3 and Shank-1 puncta, with postsynaptic changes preceding presynaptic changes. Our data suggest that a reduction in sound stimulation during auditory development induces plasticity in the molecular make-up of IHC glutamatergic synapses, but does not affect the number of these synapses. Up-regulation of synaptic proteins with sound attenuation may facilitate a compensatory increase in synaptic transmission due to the reduced sensory stimulation of the IHC. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  7. Diffuse alopecia areata is associated with intense inflammatory infiltration and CD8+ T cells in hair loss regions and an increase in serum IgE level

    Directory of Open Access Journals (Sweden)

    Ying Zhao

    2012-01-01

    Full Text Available Background: Mechanism leading to an abrupt hair loss in diffuse alopecia areata (AA remains unclear. Aims: To explore the characteristics of diffuse AA and possible factors involved in its pathogenesis. Methods: Clinical and laboratory data of 17 diffuse AA patients and 37 patchy AA patients were analyzed retrospectively. Serum IgE level was evaluated in all diffuse and patchy AA patients, as well as 27 healthy subjects without hair loss to serve as normal control. Univariate analysis was performed using Fisher′s exact test and Wilcoxon rank-sum test. Associations between inflammatory cell infiltration and laboratory values were analyzed using Spearman rank correlation test. Results: The mean age of patients with diffuse AA was 27 years with a mean disease duration of 1.77 months. All of them presented in spring or summer with an acute onset of diffuse hair loss preceded by higher incidence of scalp pruritus. Although no statistically significant difference on the incidence of atopic disease among three groups has been found, serum IgE level in diffuse AA was higher than that in healthy controls, but was comparable to that in patchy AA group. Histopathology of lesional scalp biopsies showed more intense infiltration comprising of mononuclear cells, eosinophils, CD3 + , and CD8 + T cells around hair bulbs in diffuse AA group than in patchy AA group. Moreover, IgE level in diffuse AA patients positively correlated with intensity of infiltration by mononuclear cells, eosinophils, and CD8 + T cells. Conclusions: Hypersensitivity may be involved in pathogenesis of diffuse AA. The acute onset of diffuse AA may be related to intense local inflammatory infiltration of hair loss region and an increase in serum IgE level.

  8. Possible biological dosimeters in skin and hair

    International Nuclear Information System (INIS)

    Potten, C.S.

    1986-01-01

    The hair follicle, when producing hair, contains rapidly proliferating cells, some of which are very sensitive to radiation. These can be detected by studying the incidence of dead or dying (apoptotic) cells which reach peak yields 12 h after irradiation. The yield of apoptotic cells in the follicle has been studied after various doses. The response is dose-dependent and sensitive down to levels of a few cGy. Any reduction in cell production resulting from mitotic delay or cell death might be expressed as a reduction in the width of the hair. This has been studied and the abnormality referred to as dysplasia of the hair. The fraction of dysplastic hairs is strongly dose dependent over the range 2-10 Gy. More detailed studies using higher magnification and numerous measurements of hair width should make this end-point an even more sensitive assay for radiation exposure. Preliminary measurements on the average width at a critical point along the length of the hair illustrate that doses between 1.0 and 1.5 Gy can be detected. The width of the hair is dose dependent. The length of the affected region of the hair is also probably dose dependent. Estimates for the full reduction in volume of hair should increase the sensitivity further. (orig./MG)

  9. Fractalkine Signaling Regulates Macrophage Recruitment into the Cochlea and Promotes the Survival of Spiral Ganglion Neurons after Selective Hair Cell Lesion.

    Science.gov (United States)

    Kaur, Tejbeer; Zamani, Darius; Tong, Ling; Rubel, Edwin W; Ohlemiller, Kevin K; Hirose, Keiko; Warchol, Mark E

    2015-11-11

    Macrophages are recruited into the cochlea in response to injury caused by acoustic trauma or ototoxicity, but the nature of the interaction between macrophages and the sensory structures of the inner ear remains unclear. The present study examined the role of fractalkine signaling in regulating the injury-evoked behavior of macrophages following the selective ablation of cochlear hair cells. We used a novel transgenic mouse model in which the human diphtheria toxin receptor (huDTR) is selectively expressed under the control of Pou4f3, a hair cell-specific transcription factor. Administration of diphtheria toxin (DT) to these mice resulted in nearly complete ablation of cochlear hair cells, with no evident pathology among supporting cells, spiral ganglion neurons, or cells of the cochlear lateral wall. Hair cell death led to an increase in macrophages associated with the sensory epithelium of the cochlea. Their numbers peaked at 14 days after DT and then declined at later survival times. Increased macrophages were also observed within the spiral ganglion, but their numbers remained elevated for (at least) 56 d after DT. To investigate the role of fractalkine signaling in macrophage recruitment, we crossed huDTR mice to a mouse line that lacks expression of the fractalkine receptor (CX3CR1). Disruption of fractalkine signaling reduced macrophage recruitment into both the sensory epithelium and spiral ganglion and also resulted in diminished survival of spiral ganglion neurons after hair cell death. Our results suggest a fractalkine-mediated interaction between macrophages and the neurons of the cochlea. It is known that damage to the inner ear leads to recruitment of inflammatory cells (macrophages), but the chemical signals that initiate this recruitment and the functions of macrophages in the damaged ear are unclear. Here we show that fractalkine signaling regulates macrophage recruitment into the cochlea and also promotes the survival of cochlear afferents after

  10. Correlation between membrane fluidity cellular development and stem cell differentiation

    KAUST Repository

    Noutsi, Bakiza Kamal

    2016-01-01

    Cell membranes are made up of a complex structure of lipids and proteins that diffuse laterally giving rise to what we call membrane fluidity. During cellular development, such as neuronal differentiation, cell membranes undergo dramatic structural

  11. Female pattern hair loss

    Directory of Open Access Journals (Sweden)

    Archana Singal

    2013-01-01

    Full Text Available Female pattern hair loss (FPHL is a common cause of hair loss in women characterized by diffuse reduction in hair density over the crown and frontal scalp with retention of the frontal hairline. Its prevalence increases with advancing age and is associated with significant psychological morbidity. The pathophysiology of FPHL is still not completely understood and seems to be multifactorial. Although androgens have been implicated, the involvement of androgen-independent mechanisms is evident from frequent lack of clinical or biochemical markers of hyperandrogenism in affected women. The role of genetic polymorphisms involving the androgen and estrogen receptors is being increasingly recognized in its causation and predicting treatment response to anti-androgens. There are different clinical patterns and classifications of FPHL, knowledge of which facilitates patient management and research. Chronic telogen effluvium remains as the most important differential diagnosis. Thorough history, clinical examination, and evaluation are essential to confirm diagnosis. Patients with clinical signs of androgen excess require assessment of biochemical parameters and imaging studies. It is prudent to screen the patients for metabolic syndrome and cardiovascular risk factors. The treatment comprises medical and/or surgical modalities. Medical treatment should be initiated early as it effectively arrests hair loss progression rather than stimulating regrowth. Minoxidil continues to be the first line therapy whereas anti-androgens form the second line of treatment. The progressive nature of FPHL mandates long-term treatment for sustained effect. Medical therapy may be supplemented with cosmetic concealment in those desirous of greater hair density. Surgery may be worthwhile in some carefully selected patients.

  12. Female Pattern Hair Loss

    Science.gov (United States)

    Herskovitz, Ingrid; Tosti, Antonella

    2013-01-01

    Context: Female pattern hair loss (FPHL) also known as female androgenetic alopecia is a common condition afflicting millions of women that can be cosmetically disrupting. Prompt diagnosis and treatment are essential for obtaining optimal outcome. This review addresses the clinical presentation of female pattern hair loss, its differential diagnosis and treatment modalities. Evidence Acquisition: A) Diffuse thinning of the crown region with preservation of the frontal hairline (Ludwig’s type) B) The “Christmas tree pattern” where the thinning is wider in the frontal scalp giving the alopecic area a triangular shaped figure resembling a christmas tree. C) Thinning associated with bitemporal recession (Hamilton type). Generally, FPHL is not associated with elevated androgens. Less commonly females with FPHL may have other skin or general signs of hyperandrogenism such as hirsutism, acne, irregular menses, infertility, galactorrhea and insulin resistance. The most common endocrinological abnormality associated with FPHL is polycystic ovarian syndrome (PCOS). Results: The most important diseases to consider in the differential diagnosis of FPHL include Chronic Telogen Effluvium (CTE), Permanent Alopecia after Chemotherapy (PAC), Alopecia Areata Incognito (AAI) and Frontal Fibrosing Alopecia (FFA). This review describes criteria for distinguishing these conditions from FPHL. Conclusions: The only approved treatment for FPHL, which is 2% topical Minoxidil, should be applied at the dosage of 1ml twice day for a minimum period of 12 months. This review will discuss off-label alternative modalities of treatment including 5-alfa reductase inhibitors, antiandrogens, estrogens, prostaglandin analogs, lasers, light treatments and hair transplantation. PMID:24719635

  13. Female pattern hair loss.

    Science.gov (United States)

    Herskovitz, Ingrid; Tosti, Antonella

    2013-10-01

    Female pattern hair loss (FPHL) also known as female androgenetic alopecia is a common condition afflicting millions of women that can be cosmetically disrupting. Prompt diagnosis and treatment are essential for obtaining optimal outcome. This review addresses the clinical presentation of female pattern hair loss, its differential diagnosis and treatment modalities. A) Diffuse thinning of the crown region with preservation of the frontal hairline (Ludwig's type) B) The "Christmas tree pattern" where the thinning is wider in the frontal scalp giving the alopecic area a triangular shaped figure resembling a christmas tree. C) Thinning associated with bitemporal recession (Hamilton type). Generally, FPHL is not associated with elevated androgens. Less commonly females with FPHL may have other skin or general signs of hyperandrogenism such as hirsutism, acne, irregular menses, infertility, galactorrhea and insulin resistance. The most common endocrinological abnormality associated with FPHL is polycystic ovarian syndrome (PCOS). The most important diseases to consider in the differential diagnosis of FPHL include Chronic Telogen Effluvium (CTE), Permanent Alopecia after Chemotherapy (PAC), Alopecia Areata Incognito (AAI) and Frontal Fibrosing Alopecia (FFA). This review describes criteria for distinguishing these conditions from FPHL. The only approved treatment for FPHL, which is 2% topical Minoxidil, should be applied at the dosage of 1ml twice day for a minimum period of 12 months. This review will discuss off-label alternative modalities of treatment including 5-alfa reductase inhibitors, antiandrogens, estrogens, prostaglandin analogs, lasers, light treatments and hair transplantation.

  14. Elementary properties of CaV1.3 Ca(2+) channels expressed in mouse cochlear inner hair cells.

    Science.gov (United States)

    Zampini, Valeria; Johnson, Stuart L; Franz, Christoph; Lawrence, Neil D; Münkner, Stefan; Engel, Jutta; Knipper, Marlies; Magistretti, Jacopo; Masetto, Sergio; Marcotti, Walter

    2010-01-01

    Mammalian cochlear inner hair cells (IHCs) are specialized to process developmental signals during immature stages and sound stimuli in adult animals. These signals are conveyed onto auditory afferent nerve fibres. Neurotransmitter release at IHC ribbon synapses is controlled by L-type Ca(V)1.3 Ca(2+) channels, the biophysics of which are still unknown in native mammalian cells. We have investigated the localization and elementary properties of Ca(2+) channels in immature mouse IHCs under near-physiological recording conditions. Ca(V)1.3 Ca(2+) channels at the cell pre-synaptic site co-localize with about half of the total number of ribbons present in immature IHCs. These channels activated at about 70 mV, showed a relatively short first latency and weak inactivation, which would allow IHCs to generate and accurately encode spontaneous Ca(2+) action potential activity characteristic of these immature cells. The Ca(V)1.3 Ca(2+) channels showed a very low open probability (about 0.15 at 20 mV: near the peak of an action potential). Comparison of elementary and macroscopic Ca(2+) currents indicated that very few Ca(2+) channels are associated with each docked vesicle at IHC ribbon synapses. Finally, we found that the open probability of Ca(2+) channels, but not their opening time, was voltage dependent. This finding provides a possible correlation between presynaptic Ca(2+) channel properties and the characteristic frequency/amplitude of EPSCs in auditory afferent fibres.

  15. Inhibition of H3K9me2 Reduces Hair Cell Regeneration after Hair Cell Loss in the Zebrafish Lateral Line by Down-Regulating the Wnt and Fgf Signaling Pathways

    Science.gov (United States)

    Tang, Dongmei; Lin, Qin; He, Yingzi; Chai, Renjie; Li, Huawei

    2016-01-01

    The activation of neuromast (NM) supporting cell (SC) proliferation leads to hair cell (HC) regeneration in the zebrafish lateral line. Epigenetic mechanisms have been reported that regulate HC regeneration in the zebrafish lateral line, but the role of H3K9me2 in HC regeneration after HC loss remains poorly understood. In this study, we focused on the role of H3K9me2 in HC regeneration following neomycin-induced HC loss. To investigate the effects of H3K9me2 in HC regeneration, we took advantage of the G9a/GLP-specific inhibitor BIX01294 that significantly reduces the dimethylation of H3K9. We found that BIX01294 significantly reduced HC regeneration after neomycin-induced HC loss in the zebrafish lateral line. BIX01294 also significantly reduced the proliferation of NM cells and led to fewer SCs in the lateral line. In situ hybridization showed that BIX01294 significantly down-regulated the Wnt and Fgf signaling pathways, which resulted in reduced SC proliferation and HC regeneration in the NMs of the lateral line. Altogether, our results suggest that down-regulation of H3K9me2 significantly decreases HC regeneration after neomycin-induced HC loss through inactivation of the Wnt/β-catenin and Fgf signaling pathways. Thus H3K9me2 plays a critical role in HC regeneration. PMID:27303264

  16. Inhibition of H3K9me2 Reduces Hair Cell Regeneration after Hair Cell Loss in the Zebrafish Lateral Line by Down-Regulating the Wnt and Fgf Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Dongmei eTang

    2016-05-01

    Full Text Available The activation of neuromast supporting cell (SC proliferation leads to hair cell (HC regeneration in the zebrafish lateral line. Epigenetic mechanisms have been reported that regulate HC regeneration in the zebrafish lateral line, but the role of H3K9me2 in HC regeneration after HC loss remains poorly understood. In this study, we focused on the role of H3K9me2 in HC regeneration following neomycin-induced HC loss. To investigate the effects of H3K9me2 in HC regeneration, we took advantage of the G9a/GLP-specific inhibitor BIX01294 that significantly reduces the dimethylation of H3K9. We found that BIX01294 significantly reduced HC regeneration after neomycin-induced HC loss in the zebrafish lateral line. BIX01294 also significantly reduced the proliferation of neuromast cells and led to fewer SCs in the lateral line. In situ hybridization showed that BIX01294 significantly down-regulated the Wnt and Fgf signaling pathways, which resulted in reduced SC proliferation and HC regeneration in the neuromasts of the lateral line. Altogether, our results suggest that down-regulation of H3K9me2 significantly decreases HC regeneration after neomycin-induced HC loss through inactivation of the Wnt/β-catenin and Fgf signaling pathways. Thus H3K9me2 plays a critical role in HC regeneration.

  17. Membrane glycoproteins of differentiating skeletal muscle cells

    International Nuclear Information System (INIS)

    Miller, K.R.; Remy, C.N.; Smith, P.B.

    1987-01-01

    The composition of N-linked glycoprotein oligosaccharides was studied in myoblasts and myotubes of the C2 muscle cell line. Oligosaccharides were radioactively labelled for 15 hr with [ 3 H] mannose and plasma membranes isolated. Ten glycopeptides were detected by SDS-PAGE and fluorography. The extent of labelling was 4-6 fold greater in myoblasts vs myotubes. A glycopeptide of Mr > 100,000 was found exclusively in myoblast membranes. Lectin chromatography revealed that the proportion of tri-, tetranntenary, biantennary and high mannose chains was similar throughout differentiation. The high mannose chain fraction was devoid of hybrid chains. The major high mannose chain contained nine mannose residues. The higher level of glycopeptide labelling in myoblasts vs myotubes corresponded to a 5-fold greater rate of protein synthesis. Pulse-chase experiments were used to follow the synthesis of the Dol-oligosaccharides. Myoblasts and myotubes labelled equivalently the glucosylated tetradecasaccharide but myoblasts labelled the smaller intermediates 3-4 greater than myotubes. Myoblasts also exhibited a 2-3 fold higher Dol-P dependent glycosyl transferase activity for chain elongation and Dol-sugar synthesis. Together these results show that the degree of protein synthesis and level of Dol-P are contributing factors in the higher capacity of myoblasts to produce N-glycoproteins compared to myotubes

  18. Differential marker expression by cultures rich in mesenchymal stem cells

    Science.gov (United States)

    2013-01-01

    Background Mesenchymal stem cells have properties that make them amenable to therapeutic use. However, the acceptance of mesenchymal stem cells in clinical practice requires standardized techniques for their specific isolation. To date, there are no conclusive marker (s) for the exclusive isolation of mesenchymal stem cells. Our aim was to identify markers differentially expressed between mesenchymal stem cell and non-stem cell mesenchymal cell cultures. We compared and contrasted the phenotype of tissue cultures in which mesenchymal stem cells are rich and rare. By initially assessing mesenchymal stem cell differentiation, we established that bone marrow and breast adipose cultures are rich in mesenchymal stem cells while, in our hands, foreskin fibroblast and olfactory tissue cultures contain rare mesenchymal stem cells. In particular, olfactory tissue cells represent non-stem cell mesenchymal cells. Subsequently, the phenotype of the tissue cultures were thoroughly assessed using immuno-fluorescence, flow-cytometry, proteomics, antibody arrays and qPCR. Results Our analysis revealed that all tissue cultures, regardless of differentiation potential, demonstrated remarkably similar phenotypes. Importantly, it was also observed that common mesenchymal stem cell markers, and fibroblast-associated markers, do not discriminate between mesenchymal stem cell and non-stem cell mesenchymal cell cultures. Examination and comparison of the phenotypes of mesenchymal stem cell and non-stem cell mesenchymal cell cultures revealed three differentially expressed markers – CD24, CD108 and CD40. Conclusion We indicate the importance of establishing differential marker expression between mesenchymal stem cells and non-stem cell mesenchymal cells in order to determine stem cell specific markers. PMID:24304471

  19. Expression and localization of VEGFR-2 in hair follicles during induced hair growth in mice.

    Science.gov (United States)

    Wu, Xian-Jie; Jing, Jing; Lu, Zhong-Fa; Zheng, Min

    2018-06-16

    Recently, VEGFR-2 has been detected not only in vascular and lymphatic endothelial cells but also in some non-vascular endothelial cells, particularly human hair follicles, sebaceous glands, and sweat glands. In addition, VEGFR-2 has been confirmed to play direct roles in hair follicle keratinocyte regulation beyond simply angiogenesis. To elucidate whether VEGFR-2 activation plays a role in hair follicle cycling regulation, immunofluorescence of VEGFR-2 expression was performed during hair cycling of the dorsum of the mouse induced by hair plucking. We observed that staining for VEGFR-2 in hair follicles during anagen II and IV was much stronger than during anagen VI, catagen and telogen. During anagen II, intense staining for VEGFR-2 was observed on the keratinocyte strands of the hair follicle. Subsequently, we detected intense staining for VEGFR-2 in the ORS, IRS and hair bulb during anagen IV. Moderate staining for VEGFR-2 was detected in the ORS and hair bulb, but staining was most intense in IRS during anagen VI. During catagen, staining for VEGFR-2 in the IRS remained intense, while staining in the ORS and hair bulb was significantly weakened and was negative in the dermal papilla. During telogen, we detected VEGFR-2 in germ cells, cap, and club hair adjoining the epidermis. In conclusion, VEGFR-2 was expressed on the hair follicles of the dorsum of the mouse and varied in expression on the mouse hair follicles during hair cycling, suggesting that VEGFR-2 may exert roles in hair cycle regulation in hair follicles on the dorsum of mice.

  20. Schwann cells promote neuronal differentiation of bone marrow ...

    African Journals Online (AJOL)

    It has been suggested that the BMSCs have the capacity to differentiate into neurons under specific experimental conditions, using chemical factors. In this study, we showed that BMSCs can be induced to differentiate into neuron-like cells when they are co-cultured with Schwann cells by Brdu pulse label technology.

  1. Isolation and Osteogenic Differentiation of Rat Periosteum-derived Cells

    OpenAIRE

    Declercq, Heidi Andrea; De Ridder, Leo Isabelle; Cornelissen, Maria Jozefa

    2005-01-01

    Selection of appropriate cultures having an osteogenic potential is a necessity if cell/biomaterial interactions are studied in long-term cultures. Osteoblastic cells derived from rat long bones or calvaria have the disadvantage of being in an advanced differentiation stage which results in terminal differentiation within 21 days. In this regard, less differentiated periosteum-derived osteoprogenitors could be more suitable.

  2. A Conditioned Medium of Umbilical Cord Mesenchymal Stem Cells Overexpressing Wnt7a Promotes Wound Repair and Regeneration of Hair Follicles in Mice

    Directory of Open Access Journals (Sweden)

    Liang Dong

    2017-01-01

    Full Text Available Mesenchymal stem cells (MSCs can affect the microenvironment of a wound and thereby accelerate wound healing. Wnt proteins act as key mediators of skin development and participate in the formation of skin appendages such as hair. The mechanisms of action of MSCs and Wnt proteins on skin wounds are largely unknown. Here, we prepared a Wnt7a-containing conditioned medium (Wnt-CM from the supernatant of cultured human umbilical cord-MSCs (UC-MSCs overexpressing Wnt7a in order to examine the effects of this CM on cutaneous healing. Our results revealed that Wnt-CM can accelerate wound closure and induce regeneration of hair follicles. Meanwhile, Wnt-CM enhanced expression of extracellular matrix (ECM components and cell migration of fibroblasts but inhibited the migratory ability and expression of K6 and K16 in keratinocytes by enhancing expression of c-Myc. However, we found that the CM of fibroblasts treated with Wnt-CM (HFWnt-CM-CM can also promote wound repair and keratinocyte migration; but there was no increase in the number of hair follicles of regeneration. These data indicate that Wnt7a and UC-MSCs have synergistic effects: they can accelerate wound repair and induce hair regeneration via cellular communication in the wound microenvironment. Thus, this study opens up new avenues of research on the mechanisms underlying wound repair.

  3. Intracellulair Organization: A Prerequisite for Root Hair Elongation and Cell Wall Deposition

    NARCIS (Netherlands)

    Emons, A.M.C.; Ketelaar, M.J.

    2009-01-01

    Cell growth requires not only production of matter, but in addition, the targeting, transport, and delivery of this matter to the site of cell expansion. Thus, a proper organization of cell structure, the cytoarchitecture, is a necessity for cell elongation. The actual process of cell growth in a

  4. Demethylating agent, 5-azacytidine, reverses differentiation of embryonic stem cells

    International Nuclear Information System (INIS)

    Tsuji-Takayama, Kazue; Inoue, Toshiya; Ijiri, Yoshihiro; Otani, Takeshi; Motoda, Ryuichi; Nakamura, Shuji; Orita, Kunzo

    2004-01-01

    The de novo methylation activity is essential for embryonic development as well as embryonic stem (ES) cell differentiation, where the intensive and extensive DNA methylation was detected. In this study, we investigated the effects of a demethylating agent, 5-azacytidine (5-AzaC), on differentiated ES cells in order to study the possibility of reversing the differentiation process. We first induced differentiation of ES cells by forming embryoid bodies, and then the cells were treated with 5-AzaC. The cells showed some undifferentiated features such as stem cell-like morphology with unclear cell-to-cell boundary and proliferative responsiveness to LIF. Moreover, 5-AzaC increased the expressions of ES specific markers, SSEA-1, and alkaline phosphatase activity as well as ES specific genes, Oct4, Nanog, and Sox2. We also found that 5-AzaC demethylated the promoter region of H19 gene, a typical methylated gene during embryonic differentiation. These results indicate that 5-AzaC reverses differentiation state of ES cells through its DNA demethylating activity to differentiation related genes

  5. Hepatic differentiation potential of commercially available human mesenchymal stem cells.

    Science.gov (United States)

    Ong, Shin-Yeu; Dai, Hui; Leong, Kam W

    2006-12-01

    The ready availability and low immunogenicity of commercially available mesenchymal stem cells (MSC) render them a potential cell source for the development of therapeutic products. With cell source a major bottleneck in hepatic tissue engineering, we investigated whether commercially available human MSC (hMSC) can transdifferentiate into the hepatic lineage. Based on previous studies that find rapid gain of hepatic genes in bone marrow-derived stem cells cocultured with liver tissue, we used a similar approach to drive hepatic differentiation by coculturing the hMSC with rat livers treated or untreated with gadolinium chloride (GdCl(3)). After a 24-hour coculture period with liver tissue injured by GdCl(3) in a Transwell configuration, approximately 34% of the cells differentiated into albumin-expressing cells. Cocultured cells were subsequently maintained with growth factors to complete the hepatic differentiation. Cocultured cells expressed more hepatic gene markers, and had higher metabolic functions and P450 activity than cells that were only differentiated with growth factors. In conclusion, commercially available hMSC do show hepatic differentiation potential, and a liver microenvironment in culture can provide potent cues to accelerate and deepen the differentiation. The ability to generate hepatocyte-like cells from a commercially available cell source would find interesting applications in liver tissue engineering.

  6. Two pore channel 2 differentially modulates neural differentiation of mouse embryonic stem cells.

    Directory of Open Access Journals (Sweden)

    Zhe-Hao Zhang

    Full Text Available Nicotinic acid adenine dinucleotide phosphate (NAADP is an endogenous Ca(2+ mobilizing nucleotide presented in various species. NAADP mobilizes Ca(2+ from acidic organelles through two pore channel 2 (TPC2 in many cell types and it has been previously shown that NAADP can potently induce neuronal differentiation in PC12 cells. Here we examined the role of TPC2 signaling in the neural differentiation of mouse embryonic stem (ES cells. We found that the expression of TPC2 was markedly decreased during the initial ES cell entry into neural progenitors, and the levels of TPC2 gradually rebounded during the late stages of neurogenesis. Correspondingly, TPC2 knockdown accelerated mouse ES cell differentiation into neural progenitors but inhibited these neural progenitors from committing to neurons. Overexpression of TPC2, on the other hand, inhibited mouse ES cell from entering the early neural lineage. Interestingly, TPC2 knockdown had no effect on the differentiation of astrocytes and oligodendrocytes of mouse ES cells. Taken together, our data indicate that TPC2 signaling plays a temporal and differential role in modulating the neural lineage entry of mouse ES cells, in that TPC2 signaling inhibits ES cell entry to early neural progenitors, but is required for late neuronal differentiation.

  7. NOV/CCN3 impairs muscle cell commitment and differentiation

    International Nuclear Information System (INIS)

    Calhabeu, Frederico; Lafont, Jerome; Le Dreau, Gwenvael; Laurent, Maryvonne; Kazazian, Chantal; Schaeffer, Laurent; Martinerie, Cecile; Dubois, Catherine

    2006-01-01

    NOV (nephroblastoma overexpressed) is a member of a family of proteins which encodes secreted matrix-associated proteins. NOV is expressed during development in dermomyotome and limb buds, but its functions are still poorly defined. In order to understand the role of NOV in myogenic differentiation, C2C12 cells overexpressing NOV (C2-NOV) were generated. These cells failed to engage into myogenic differentiation, whereas they retained the ability to differentiate into osteoblasts. In differentiating conditions, C2-NOV cells remained proliferative, failed to express differentiation markers and lost their ability to form myotubes. Inhibition of differentiation by NOV was also observed with human primary muscle cells. Further examination of C2-NOV cells revealed a strong downregulation of the myogenic determination genes MyoD and Myf5 and of IGF-II expression. MyoD forced expression in C2-NOV was sufficient to restore differentiation and IGF-II induction whereas 10 -6 M insulin treatment had no effects. NOV therefore acts upstream of MyoD and does not affect IGF-II induction and signaling. HES1, a target of Notch, previously proposed to mediate NOV action, was not implicated in the inhibition of differentiation. We propose that NOV is a specific cell fate regulator in the myogenic lineage, acting negatively on key myogenic genes thus controlling the transition from progenitor cells to myoblasts

  8. Diclofenac and triamcinolone acetonide impair tenocytic differentiation and promote adipocytic differentiation of mesenchymal stem cells.

    Science.gov (United States)

    Fredriksson, Maritha; Li, Yan; Stålman, Anders; Haldosén, Lars-Arne; Felländer-Tsai, Li

    2013-09-02

    Tendinopathies are often empirically treated with oral/topical nonsteroidal anti-inflammatory medications and corticosteroid injections despite their unclear effects on tendon regeneration. Recent studies indicate that tendon progenitors exhibit stem cell-like properties, i.e., differentiation to osteoblasts, adipocytes, and chondrocytes, in addition to tenocytes. Our present study aims at understanding the effects of triamcinolone acetonide and diclofenac on tenocytic differentiation of mesenchymal stem cells. The murine fibroblast C3H10T1/2 cell line was induced to tenocytic differentiation by growth differentiation factor-7. Cell proliferation and differentiation with the exposure of different concentrations of triamcinolone acetonide and diclofenac were measured by WST-1 assay and real-time polymerase chain reaction analysis, respectively. Cell proliferation was decreased in a concentration-dependent manner when exposed to triamcinolone acetonide and diclofenac. In addition to tenocytic differentiation, adipocyte formation was observed, both at gene expression and microscopic level, when the cells were exposed to triamcinolone acetonide or high concentrations of diclofenac. Our results indicate that triamcinolone acetonide and diclofenac might alter mesenchymal stem cell differentiation in a nonfavorable way regarding tendon regeneration; therefore, these medications should be used with more caution clinically.

  9. Differential effects of ambient temperature on warm cell responses to infrared radiation in the bloodsucking bug Rhodnius prolixus.

    Science.gov (United States)

    Zopf, Lydia M; Lazzari, Claudio R; Tichy, Harald

    2014-03-01

    Thermoreceptors provide animals with background information about the thermal environment, which is at least indirectly a prerequisite for thermoregulation and assists bloodsucking insects in the search for their host. Recordings from peg-in-pit sensilla and tapered hairs on the antennae of the bug Rhodnius prolixus revealed two physiologically different types of warm cells. Both types responded more strongly to temperature pulses produced by switching between two air streams at different constant temperatures than to infrared radiation pulses employed in still air. In addition, both warm cells were better able to discriminate small changes in air temperature than in infrared radiation. As convective and radiant heat determines the discharge, it is impossible for a single warm cell to signal the nature of the stimulus unequivocally. Individual responses are ambiguous, not with regard to temperature change, but with regard to its source. We argue that the bugs use mechanical flow information to differentiate between pulses of convective and radiant heat. However, if pulses of radiant heat occur together with a constant temperature air stream, the mechanical cues would not allow avoiding ambiguity that convective heat introduces into radiant heat stimulation. In this situation, the warm cell in the tapered hairs produced stronger responses than those in the peg-in-pit sensilla. The reversal in the excitability of the two types of warm cells provides a criterion by which to distinguish the combination of convective and radiant heat from the stimuli presented alone.

  10. Vascular Mural Cells Promote Noradrenergic Differentiation of Embryonic Sympathetic Neurons

    Directory of Open Access Journals (Sweden)

    Vitor Fortuna

    2015-06-01

    Full Text Available The sympathetic nervous system controls smooth muscle tone and heart rate in the cardiovascular system. Postganglionic sympathetic neurons (SNs develop in close proximity to the dorsal aorta (DA and innervate visceral smooth muscle targets. Here, we use the zebrafish embryo to ask whether the DA is required for SN development. We show that noradrenergic (NA differentiation of SN precursors temporally coincides with vascular mural cell (VMC recruitment to the DA and vascular maturation. Blocking vascular maturation inhibits VMC recruitment and blocks NA differentiation of SN precursors. Inhibition of platelet-derived growth factor receptor (PDGFR signaling prevents VMC differentiation and also blocks NA differentiation of SN precursors. NA differentiation is normal in cloche mutants that are devoid of endothelial cells but have VMCs. Thus, PDGFR-mediated mural cell recruitment mediates neurovascular interactions between the aorta and sympathetic precursors and promotes their noradrenergic differentiation.

  11. Vascular Mural Cells Promote Noradrenergic Differentiation of Embryonic Sympathetic Neurons.

    Science.gov (United States)

    Fortuna, Vitor; Pardanaud, Luc; Brunet, Isabelle; Ola, Roxana; Ristori, Emma; Santoro, Massimo M; Nicoli, Stefania; Eichmann, Anne

    2015-06-23

    The sympathetic nervous system controls smooth muscle tone and heart rate in the cardiovascular system. Postganglionic sympathetic neurons (SNs) develop in close proximity to the dorsal aorta (DA) and innervate visceral smooth muscle targets. Here, we use the zebrafish embryo to ask whether the DA is required for SN development. We show that noradrenergic (NA) differentiation of SN precursors temporally coincides with vascular mural cell (VMC) recruitment to the DA and vascular maturation. Blocking vascular maturation inhibits VMC recruitment and blocks NA differentiation of SN precursors. Inhibition of platelet-derived growth factor receptor (PDGFR) signaling prevents VMC differentiation and also blocks NA differentiation of SN precursors. NA differentiation is normal in cloche mutants that are devoid of endothelial cells but have VMCs. Thus, PDGFR-mediated mural cell recruitment mediates neurovascular interactions between the aorta and sympathetic precursors and promotes their noradrenergic differentiation. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  12. Early stage differentiation of thallus cells of Porphyra haitanensis (Rhodophyta)

    Science.gov (United States)

    Wang, Sujuan; Sun, Yunlong; Lu, Anming; Wang, Guangyuan

    1987-09-01

    The early stage differentiation of thallus cells of Porphyra haitanensis T. J. Chang et B. F. Zheng was studied. Protoplasts or single cells were isolated from the blades using enzyme mixture comprising 2% sea snail gut enzyme and 1% cellulase. The isolated protoplasts or single cells were incubated in the MES medium. The cell differentiations were examined under the microscope at intervals after incubation. Four types of cell differentiation, namely, normal, abnormal, carposporangial and spermatorangial, and rhizoidal types, were observed. Since normal cell differentiations occur mostly in small thalli 50 mm in length and middle portions of big thalli 200 mm in length, it is essential to select tissues from these two kinds of thalli essential for commercial production.

  13. Differentiation of stem cells upon deprivation of exogenous FGF2

    DEFF Research Database (Denmark)

    Kjartansdóttir, Kristín Rós; Gabrielsen, Anette; Reda, Ahmed

    2012-01-01

    Establishing a model for in vitro differentiation of human embryonic stem cells (hESCs) towards the germ cell lineage could be used to identify molecular mechanisms behind germ cell differentiation that may help in understanding human infertility. Here, we evaluate whether a lack of exogenous...... fibroblast growth factor 2 (FGF2) is supporting spontaneous differentiation of hESCs cultured on human foreskin fibroblast (hFF) monolayers towards germ cell lineage. Additionally to depriving the hESCs of exogenous FGF2, cells were stimulated with all-trans retinoic acid (ATRA). To get a more comprehensive...... impression on effects of removal of FGF2 and stimulation with ATRA, we combined the results of three cell lines for each experimental setting. When combining gene expression profiles of three cell lines for 96 genes, only 6 genes showed a significant up-regulation in all cell lines, when no FGF2 was added...

  14. Epigenetic control of CD8+ T cell differentiation.

    Science.gov (United States)

    Henning, Amanda N; Roychoudhuri, Rahul; Restifo, Nicholas P

    2018-05-01

    Upon stimulation, small numbers of naive CD8 + T cells proliferate and differentiate into a variety of memory and effector cell types. CD8 + T cells can persist for years and kill tumour cells and virally infected cells. The functional and phenotypic changes that occur during CD8 + T cell differentiation are well characterized, but the epigenetic states that underlie these changes are incompletely understood. Here, we review the epigenetic processes that direct CD8 + T cell differentiation and function. We focus on epigenetic modification of DNA and associated histones at genes and their regulatory elements. We also describe structural changes in chromatin organization that affect gene expression. Finally, we examine the translational potential of epigenetic interventions to improve CD8 + T cell function in individuals with chronic infections and cancer.

  15. Survival of partially differentiated mouse embryonic stem cells in the scala media of the guinea pig cochlea.

    Science.gov (United States)

    Hildebrand, Michael S; Dahl, Hans-Henrik M; Hardman, Jennifer; Coleman, Bryony; Shepherd, Robert K; de Silva, Michelle G

    2005-12-01

    The low regenerative capacity of the hair cells of the mammalian inner ear is a major obstacle for functional recovery following sensorineural hearing loss. A potential treatment is to replace damaged tissue by transplantation of stem cells. To test this approach, undifferentiated and partially differentiated mouse embryonic stem (ES) cells were delivered into the scala media of the deafened guinea pig cochlea. Transplanted cells survived in the scala media for a postoperative period of at least nine weeks, evidenced by histochemical and direct fluorescent detection of enhanced green fluorescent protein (EGFP). Transplanted cells were discovered near the spiral ligament and stria vascularis in the endolymph fluid of the scala media. In some cases, cells were observed close to the damaged organ of Corti structure. There was no evidence of significant immunological rejection of the implanted ES cells despite the absence of immunosuppression. Our surgical approach allowed efficient delivery of ES cells to the scala media while preserving the delicate structures of the cochlea. This is the first report of the survival of partially differentiated ES cells in the scala media of the mammalian cochlea, and it provides support for the potential of cell-based therapies for sensorineural hearing impairment.

  16. In vitro germ cell differentiation from cynomolgus monkey embryonic stem cells.

    Directory of Open Access Journals (Sweden)

    Kaori Yamauchi

    Full Text Available BACKGROUND: Mouse embryonic stem (ES cells can differentiate into female and male germ cells in vitro. Primate ES cells can also differentiate into immature germ cells in vitro. However, little is known about the differentiation markers and culture conditions for in vitro germ cell differentiation from ES cells in primates. Monkey ES cells are thus considered to be a useful model to study primate gametogenesis in vitro. Therefore, in order to obtain further information on germ cell differentiation from primate ES cells, this study examined the ability of cynomolgus monkey ES cells to differentiate into germ cells in vitro. METHODS AND FINDINGS: To explore the differentiation markers for detecting germ cells differentiated from ES cells, the expression of various germ cell marker genes was examined in tissues and ES cells of the cynomolgus monkey (Macaca fascicularis. VASA is a valuable gene for the detection of germ cells differentiated from ES cells. An increase of VASA expression was observed when differentiation was induced in ES cells via embryoid body (EB formation. In addition, the expression of other germ cell markers, such as NANOS and PIWIL1 genes, was also up-regulated as the EB differentiation progressed. Immunocytochemistry identified the cells expressing stage-specific embryonic antigen (SSEA 1, OCT-4, and VASA proteins in the EBs. These cells were detected in the peripheral region of the EBs as specific cell populations, such as SSEA1-positive, OCT-4-positive cells, OCT-4-positive, VASA-positive cells, and OCT-4-negative, VASA-positive cells. Thereafter, the effect of mouse gonadal cell-conditioned medium and growth factors on germ cell differentiation from monkey ES cells was examined, and this revealed that the addition of BMP4 to differentiating ES cells increased the expression of SCP1, a meiotic marker gene. CONCLUSION: VASA is a valuable gene for the detection of germ cells differentiated from ES cells in monkeys, and the

  17. Id2 reinforces TH1 cell differentiation and inhibits E2A to repress TFH cell differentiation

    Science.gov (United States)

    Shaw, Laura A.; Bélanger, Simon; Omilusik, Kyla D.; Cho, Sunglim; Scott-Browne, James P.; Nance, J. Philip; Goulding, John; Lasorella, Anna; Lu, Li-Fan; Crotty, Shane; Goldrath, Ananda W.

    2016-01-01

    Differentiation of T helper (TH) effector subsets is critical for host protection. E protein transcription factors and Id proteins are important arbiters of T cell development, but their role in differentiation of TH1 and TFH cells is not well understood. TH1 cells showed robust Id2 expression compared to TFH cells, and RNAi depletion of Id2 increased TFH cell frequencies. Further, TH1 cell differentiation was blocked by Id2 deficiency, leading to E protein-dependent accumulation of effector cells with mixed characteristics during viral infection and severely impaired generation of TH1 cells following Toxoplasma gondii infection. The TFH-defining transcriptional repressor Bcl6 bound the Id2 locus, providing a mechanism for the bimodal Id2 expression and reciprocal development of TH1 and TFH cell fates. PMID:27213691

  18. Telogen Effluvium Hair Loss

    Science.gov (United States)

    ... Category: Share: Yes No, Keep Private Telogen Effluvium Hair Loss Share | It is normal to lose up to ... months after the "shock". This sudden increase in hair loss, usually described as the hair coming out in ...

  19. Hair Pulling (Trichotillomania)

    Science.gov (United States)

    ... for Families - Vietnamese Spanish Facts for Families Guide Hair Pulling (Trichotillomania) No. 96; Reviewed July 2013 It ... for children and adolescents to play with their hair. However, frequent or obsessive hair pulling can lead ...

  20. Calcium-loaded 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid blocks cell-to-cell diffusion of carboxyfluorescein in staminal hairs of Setcreasea purpurea.

    Science.gov (United States)

    Tucker, E B

    1990-08-01

    The effect of microinjected calcium-loaded 1,2-bis(2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid (CaBAPTA) on cell-to-cell diffusion of carboxyfluorescein (CF) was examined in staminal hairs of S. purpurea Boom. The CaBAPTA was microinjected into the cytoplasm of the staminal hairs either with CF or prior to a subsequent microinjection of CF. The cell-to-cell diffusion of CF along the hair was monitored using enhanced-fluorescence video microscopy. Cytoplasmic streaming stopped in cells treated with CaBAPTA, indicating that intracellular Ca(2+) had increased. Cell-to-cell diffusion of CF was blocked in cells treated with Ca-BAPTA. An inhibition of cytoplasmic streaming and cell-to-cell diffusion was observed in the cells adjoining the CaBAPTA-microinjected cell, indicating that the Ca-BAPTA appeared to pass through plasmodesmata. While cytoplasmic streaming resumed 5-10 min after CaBAPTA treatment, cell-to-cell diffusion did not resume until 30-120 min later. These data support an involvement of calcium in the regulation of cell-to-cell communication in plants.

  1. Hypercholesterolemia Induces Differentiation of Regulatory T Cells in the Liver.

    Science.gov (United States)

    Mailer, Reiner K W; Gisterå, Anton; Polyzos, Konstantinos A; Ketelhuth, Daniel F J; Hansson, Göran K

    2017-05-26

    The liver is the central organ that responds to dietary cholesterol intake and facilitates the release and clearance of lipoprotein particles. Persistent hypercholesterolemia leads to immune responses against lipoprotein particles that drive atherosclerosis. However, the effect of hypercholesterolemia on hepatic T-cell differentiation remains unknown. To investigate hepatic T-cell subsets upon hypercholesterolemia. We observed that hypercholesterolemia elevated the intrahepatic regulatory T (Treg) cell population and increased the expression of transforming growth factor-β1 in the liver. Adoptive transfer experiments revealed that intrahepatically differentiated Treg cells relocated to the inflamed aorta in atherosclerosis-prone low-density lipoprotein receptor deficient ( Ldlr -/- ) mice. Moreover, hypercholesterolemia induced the differentiation of intrahepatic, but not intrasplenic, Th17 cells in wild-type mice, whereas the disrupted liver homeostasis in hypercholesterolemic Ldlr -/- mice led to intrahepatic Th1 cell differentiation and CD11b + CD11c + leukocyte accumulation. Our results elucidate a new mechanism that controls intrahepatic T-cell differentiation during atherosclerosis development and indicates that intrahepatically differentiated T cells contribute to the CD4 + T-cell pool in the atherosclerotic aorta. © 2017 American Heart Association, Inc.

  2. The Root Hair Specific SYP123 Regulates the Localization of Cell Wall Components and Contributes to Rizhobacterial Priming of Induced Systemic Resistance

    Directory of Open Access Journals (Sweden)

    Cecilia Rodriguez-Furlán

    2016-07-01

    Full Text Available Root hairs are important for nutrient and water uptake and are also critically involved the interaction with soil inhabiting microbiota. Root hairs are tubular-shaped outgrowths that emerge from trichoblasts. This polarized elongation is maintained and regulated by a robust mechanism involving the endomembrane secretory and endocytic system. Members of the syntaxin family of SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptor in plants (SYP, have been implicated in regulation of the fusion of vesicles with the target membranes in both exocytic and endocytic pathways. One member of this family, SYP123, is expressed specifically in the root hairs and accumulated in the growing tip region. This study shows evidence of the SYP123 role in polarized trafficking using knockout insertional mutant plants. We were able to observe defects in the deposition of cell wall proline rich protein PRP3 and cell wall polysaccharides. In a complementary strategy, similar results were obtained using a plant expressing a dominant negative soluble version of SYP123 (SP2 fragment lacking the transmembrane domain. The evidence presented indicates that SYP123 is also regulating PRP3 protein distribution by recycling by endocytosis. We also present evidence that indicates that SYP123 is necessary for the response of roots to plant growth promoting rhizobacterium (PGPR in order to trigger trigger induced systemic response (ISR. Plants with a defective SYP123 function were unable to mount a systemic acquired resistance (SAR in response to bacterial pathogen infection and induced systemic resistance (ISR upon interaction with rhizobacteria. These results indicated that SYP123 was involved in the polarized localization of protein and polysaccharides in growing root hairs and that this activity also contributed to the establishment of effective plant defense responses. Root hairs represent very plastic structures were many biotic and abiotic factors

  3. Actin depolymerization enhances adipogenic differentiation in human stromal stem cells.

    Science.gov (United States)

    Chen, Li; Hu, Huimin; Qiu, Weimin; Shi, Kaikai; Kassem, Moustapha

    2018-05-01

    Human stromal stem cells (hMSCs) differentiate into adipocytes that play a role in skeletal tissue homeostasis and whole body energy metabolism. During adipocyte differentiation, hMSCs exhibit significant changes in cell morphology suggesting changes in cytoskeletal organization. Here, we examined the effect of direct modulation of actin microfilament dynamics on adipocyte differentiation. Stabilizing actin filaments in hMSCs by siRNA-mediated knock down of the two main actin depolymerizing factors (ADFs): Cofilin 1 (CFL1) and Destrin (DSTN) or treating the cells by Phalloidin reduced adipocyte differentiation as evidenced by decreased number of mature adipocytes and decreased adipocyte specific gene expression (ADIPOQ, LPL, PPARG, FABP4). In contrast, disruption of actin cytoskeleton by Cytochalasin D enhanced adipocyte differentiation. Follow up studies revealed that the effects of CFL1 on adipocyte differentiation depended on the activity of LIM domain kinase 1 (LIMK1) which is the major upstream kinase of CFL1. Inhibiting LIMK by its specific chemical inhibitor LIMKi inhibited the phosphorylation of CFL1 and actin polymerization, and enhanced the adipocyte differentiation. Moreover, treating hMSCs by Cytochalasin D inhibited ERK and Smad2 signaling and this was associated with enhanced adipocyte differentiation. On the other hand, Phalloidin enhanced ERK and Smad2 signaling, but inhibited adipocyte differentiation which was rescued by ERK specific chemical inhibitor U0126. Our data provide a link between restructuring of hMSCs cytoskeleton and hMSCs lineage commitment and differentiation. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Identification of transcript regulatory patterns in cell differentiation.

    Science.gov (United States)

    Gusnanto, Arief; Gosling, John Paul; Pope, Christopher

    2017-10-15

    Studying transcript regulatory patterns in cell differentiation is critical in understanding its complex nature of the formation and function of different cell types. This is done usually by measuring gene expression at different stages of the cell differentiation. However, if the gene expression data available are only from the mature cells, we have some challenges in identifying transcript regulatory patterns that govern the cell differentiation. We propose to exploit the information of the lineage of cell differentiation in terms of correlation structure between cell types. We assume that two different cell types that are close in the lineage will exhibit many common genes that are co-ex