The viral defense gene RNaseL acts as a regeneration repressor
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ABSTRACT: Normal Human Epidermal Keratinocytes treated with either Q-VD-OPh or vehicle,were prepared for protein analysis using proteomics approach.Protein expression changes were discussed.
Project description:Mammalian injury responses are predominantly characterized by fibrosis and scarring rathe than functional regeneration.This limited regenerative capacity in mammals could reflect loss of pro-regeneration programs or active suppression by genes functioning akin to tumor suppressors.
Project description:Our goal is to find new genes regulated by p21 in human primary cells . To get it we carried out a gene expression profiling in two different models, human myeloid leukemia K562 cells and human keratinocytes both of them with conditional expression of p21. In order to identify genes specifically modulated by p21 we compared with the cell line with overexpression of p27, because p21 and p27 belong to the same gene family and regulated the same genes specially in cell cycle. So, our intention is to identify only genes regulated by p21 and not p27. In order to confirm these results we studied the p21-dependent repression of mitotic genes in a different cellular system. We chose human primary keratinocytes because they are non-tumorigenic, non-immortalized and epithelial cells, in contrast to human myeloid leukemia K562 cells. Human primary keratinocytes were infected with recombinant adenoviruses expressing the full-length p21 protein. A dramatic increase in p21 in infected keratinocytes was demonstrated by RT-qPCR (as we show in the manuscript). As controls, we also infected the keratinocytes with adenovirus carrying the genes for p27 which overexpression was also confirmed by RT-qPCR (as we show in the manuscript). We prepared RNA 24 h after infection and performed large-scale expression assay using the Afftymetrix platform. The clustering analysis revealed that p21 provoked the down-regulation of a number genes involved in cell cycle control not shared by cells expressing p27 (as we show in the manuscript). Our goal, has been getting genes regulated more strongly by p21 and not by p27 in cell cycle and mitosis. Our result are supported because we have found the same genes in two different models and also we have validated (by RT-qPCR) more than 20 cell cycle and mitotic genes, found in our affymetrix arrays. Also we have found the region of p21 that is sufficient for gene regulation and for one gene we have described as p21 bind to the promoter. Finally, we have discussed in our manuscript how p21 can do this regulation by bioinformatic analysis of p21-target genes. The success of this study is to describe a new role of p21 as a transcriptional co-repressor in some systems.
Project description:The aim of the study was to describe the function of miR-146a in human skin keratinocytes in relation to chronic skin diseases. miR-146a precursor and the control were transfected into human primary keratinocytes treated with IFN-gamma, TNF-alpha or left untreated. mRNA expression profiles of each conditions were detected.
Project description:Skin exposed to environmental threats including injuries and oxidative stress developed an efficient but not fully recognized systems of repair and antioxidant protection. In this project we provide evidence that Foxn1 in keratinocytes regulates elements of electron transport chain and participates in thioredoxin system (Txn2, Txnrd3, Srxn1) induction, particularly under hypoxic environment. It is shown that Foxn1 in keratinocytes upregulate glutathione thioredoxin reductase 3 (Txnrd3) protein, and high levels of Txnrd3 mRNA were detected in injured skin of Foxn1+/+ mice. It also shown that Foxn1 strongly downregulate CCN2 protein participating in reconstruction of the epidermis after injury. As in vitro assay revealed that Foxn1 controls keratinocytes migration stimulating it under normoxia and suppressing under hypoxia. Keratinocytes overexpressing Foxn1 and exposed to hypoxia showed reduced ability to promote angiogenesis by downregulation of Vegfa. In conclusion, this study showed a new mechanism in which Foxn1, along with hypoxia, participates in the activation of antioxidant defense and controls functional properties of keratinocytes.
Project description:Mice with deficient expression of RASSF9 exhibit intriguing phenotypes of skin-related pathology, including abnormal thickening of the epidermis, dysregulated proliferation of keratinocytes, and alopecia. To delineate the underlying mechanism, we profiled gene expression in keratinocytes of RASSF9-mutant mice to identify targets whose expressions were affected by RASSF9 gene deletion. Primary keratinocytes from neonatal ICR mice of wildtype control (WT) or homozygous RASSF9 deletion (RASSF9-/-) were harvested for RNA extraction and hybridization on Affymetrix microarrays. For WT, a single microarray hybridization was performed. For RASSF9-/-, one hybridization was performed for each of two independent samples.
Project description:Cultured epidermal keratinocyte controls used for IFNg, TNFa and IL1 treatment. Interferon (IFN)-gamma, is a multifunctional, immunomodulatory cytokine with cell type-specific antiviral activities, particularly important in skin, where it is implicated in many diseases ranging from warts to psoriasis and cancer. Since epidermis is our first line of defence against many viruses, we investigated the molecular processes regulated by IFN-gamma in keratinocytes using DNA microarrays. We identified the IFN-gamma-regulated keratinocyte-specific genes in keratinocytes, IFN-gamma-induced tight junction proteins, presumably to deny viruses paracellular routes of infection. Furthermore, differing from published data, we find that IFN-gamma suppressed the expression of keratinocytes differentiation markers including desmosomal proteins, cornified envelope components and suprabasal cytokeratins. Inhibition of differentiation may interfere with the epidermal tropism of viruses that require differentiating cells for growth, for example, papillomaviruses. As in other cell types, IFN-gamma induced HLA, cell adhesion and proteasome proteins, facilitating leukocyte attraction and antigen-presentation by keratinocytes. IFN-gamma also induced chemokine/cytokines specific for mononuclear cells. IFN-gamma suppressed the expression of over 100 genes responsible for cell cycle, DNA replication and RNA metabolism, thereby shutting down many nuclear processes and denying viruses a healthy cell in which to replicate. Thus, uniquely in keratinocytes, IFN-gamma initiates a well-organized molecular programme boosting host antiviral defences, obstructing viral entry, suppressing cell proliferation and impeding differentiation.
Project description:MiR-31 is one of the most highly overexpressed miRNAs in psoriasis skin; however, its biological role in the disease has not been studied. Here we show that miR-31 is markedly overexpressed in psoriasis keratinocytes. To study the biological role of miR-31 in keratinocytes, we transfected miR-31 hairpin inhibitor (anti-miR-31) into primary human keratinocytes to inhibit endogenous miR-31. We performed a global transcriptome analysis of keratinocytes upon suppression of endogenous miR-31 using Affymetrix arrays. Expression profiling of primary human keratinocytes transfected with 10nM miR-31 hairpin inhibitor (anti-miR-31) or control hairpin RNA (anti-miR-Ctrl) for 48 hours (biological triplicates in each group) was performed using the Affymetrix GeneTitan system.
Project description:Transcriptional coactivator Mediator complex facilitates transcription of various transcription factors. Previously, we have generated Med1 conditional null mice, where a critical subunit of Mediator, Med1, is removed from keratinocytes. Here we present evidence that ablation of Med1 accelerated epidermal regeneration after injury. As bulge keratinocyte stem cells are important contributors to regenerate epidermis, we first analyzed properties of stem cells in Med1 null mice. BrdU long retaining analysis revealed that deletion of Med1 still maintained quiescence of bulge keratinocyte stem cells, despite of general hyperplasia observed in Med1 deficient keratinocytes. Gene expression analysis demonstrated that a series of niche matrix proteins decreased in Med1 deficient keratinocytes. In contrast, the expression of stem cell marker Sox9 was not altered, suggesting stem cells are present but activated because of abnormal niche surrounding stem cells. In addition, Med1 deletion suppressed injury induced inflammatory reaction, which indirectly regulates epidermal regeneration. We also indicated that TGFβ1 significantly decreased in both bulge and epidermal keratinocytes upon Med1 deletion. Our study demonstrates that coactivator Med1 has a critical role to maintain bulge stem cells and epidermal regeneration presumably through regulation in TGFβ signaling. n=3 WT and KO (each group contains keratinocytes isolated from adult skins excised from 2 mice)
Project description:Targets of Retinoic Acid (RA) were identified in primary human epidermal keratinocytes grown in the presence or absence of all-trans retinoic acid for 1, 4, 24, 48 and 72 hours. Targets of Thyroid Hormone (T3) were identified in primary human epidermal keratinocytes grown in the presence or absence of the hormone; same controls as for RA. Time course, 1, 4, 24, 48 and 72 hours
Project description:An essential function of the human epidermis is the maintenance of a protective barrier against the environment. As a consequence, keratinocytes, which make up this layer of the skin, undergo an elaborate process of self-renewal, terminal differentiation and cell death. Misregulation of these processes can lead to several human diseases including psoriasis and basal cell and squamous cell carcinomas. To identify novel regulators of keratinocyte differentiation, a cell-based screen of small molecule libraries was carried out for molecules that induce terminal differentiation of normal human epidermal keratinocytes (NHEKs). One class of molecules was identified, the 2-(3,4,5-trimethoxy-phenylamino)-pyrrolo[2,3-d]pyrimidines, which were shown to induce differentiation of epidermal progenitor cells to terminally differentiated keratinocytes. These molecules serve as useful mechanistic probes of the cellular differentiation programs that regulate the formation and homeostasis of the epidermis, and may lead to novel therapeutic approaches for the treatment of skin hyperproliferative disorders. Experiment Overall Design: samples were taken from duplicate treatments of cells with DMSO or PP-2 (compound 9) at various time points