Browse
Submit Data
Databases
API
Help

Dataset Information

7 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

IKKalpha, a critical regulator of epidermal differentiation and a suppressor of skin cancer.

ABSTRACT: IkappaB kinase alpha (IKKalpha), one of the two catalytic subunits of the IKK complex involved in nuclear factor kappaB (NF-kappaB) activation, also functions as a molecular switch that controls epidermal differentiation. This unexpected function requires IKKalpha nuclear translocation but does not depend on its kinase activity, and is independent of NF-kappaB signalling. Ikkalpha(-/-) mice present with a hyperproliferative and undifferentiated epidermis characterized by complete absence of a granular layer and stratum corneum. Ikkalpha-deficient keratinocytes do not express terminal differentiation markers and continue to proliferate even when subjected to differentiation-inducing stimuli. This antiproliferative function of IKKalpha is also important for the suppression of squamous cell carcinogenesis. The exact mechanisms by which nuclear IKKalpha controls keratinocyte proliferation and differentiation remained mysterious for some time. Recent studies, however, have revealed that IKKalpha is a major cofactor in a TGFbeta-Smad2/3 signalling pathway that is Smad4 independent. This pathway controls cell cycle withdrawal during keratinocyte terminal differentiation. Although these are not the only functions of nuclear IKKalpha, this multifunctional protein is a key regulator of keratinocyte and epidermal differentiation and a critical suppressor of skin cancer.

SUBMITTER: Descargues P

PROVIDER: S-EPMC2556095 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

IKKalpha is required to maintain skin homeostasis and prevent skin cancer.

Project description:It has long been known that excessive mitotic activity due to H-Ras can block keratinocyte differentiation and cause skin cancer. It is not clear whether there are any innate surveillants that are able to ensure that keratinocytes undergo terminal differentiation, preventing the disease. IKKalpha induces keratinocyte terminal differentiation, and its downregulation promotes skin tumor development. However, its intrinsic function in skin cancer is unknown. Here, we found that mice with IKKalpha deletion in keratinocytes develop a thickened epidermis and spontaneous squamous cell-like carcinomas. Inactivation of epidermal growth factor receptor (EGFR) or reintroduction of IKKalpha inhibits excessive mitosis, induces terminal differentiation, and prevents skin cancer through repressing an EGFR-driven autocrine loop. Thus, IKKalpha serves as an innate surveillant.

| S-EPMC7263012 | biostudies-literature

RNA-binding protein quaking, a critical regulator of colon epithelial differentiation and a suppressor of colon cancer.

Project description:Colon cancer is one of the best understood neoplasms from a genetic perspective, yet it remains the second most common cause of cancer-related death. Post-transcriptional regulation mediated by RNA-binding proteins or microRNAs coordinately targets multiple genes, holding promise involved in colon cancer initiation and development. Here we studied the role of RNA-binding protein quaking (QKI) in colon cancer.We observed the expression pattern of QKI in normal colon and colon cancers through reverse-transcription polymerase chain reaction and Western blot. Bisulfite sequencing and methylation-specific PCR were applied for QKI promoter methylation analysis. We used enterocyte differentiation markers and soft agar assay to test the role of QKI in colon differentiation and colon cancer development. 3' Untranslated region (UTR) reporter assay and RNA-immunoprecipitation were used to confirm the interaction between QKI and beta-catenin or p27.QKI is significantly down-regulated and even absent in some colon cancers, which is at least partially because of the promoter hypermethylation. Forced expression of QKI in the colon cancer cells increased the expression of enterocyte differentiation marker intestinal alkaline phosphatase and lactase, together with the enhancement of p27Kip1 protein level, and membrane localized beta-catenin. Finally, QKI overexpression reduced the proliferation and tumorigenesis ability.Our study establishes that QKI functions as a principal regulator in the differentiation of colon epithelium and a suppressor of carcinogenesis through coordinately targeting multiple genes associated with cell growth and differentiation, whose deregulation by methylation is involved in colon cancer onset and progress.

| S-EPMC2847771 | biostudies-literature

IKKalpha is a critical coregulator of a Smad4-independent TGFbeta-Smad2/3 signaling pathway that controls keratinocyte differentiation.

Project description:Cell-cycle exit and differentiation of suprabasal epidermal keratinocytes require nuclear IkappaB kinase alpha (IKKalpha), but not its protein kinase activity. IKKalpha also is a suppressor of squamous cell carcinoma (SCC), but its mode of action remains elusive. Postulating that IKKalpha may serve as a transcriptional regulator in keratinocytes, we searched for cell-cycle-related genes that could illuminate this function. IKKalpha was found to control several Myc antagonists, including Mad1, Mad2, and Ovol1, through the association with TGFbeta-regulated Smad2/3 transcription factors and is required for Smad3 recruitment to at least one of these targets. Surprisingly, Smad2/3-dependent Mad1 induction and keratinocyte differentiation are independent of Smad4, the almost universal coregulator of canonical TGFbeta signaling. IKKalpha also is needed for nuclear accumulation of activated Smad2/3 in the epidermis, and Smad2/3 are required for epidermal differentiation. We suggest that a TGFbeta-Smad2/3-IKKalpha axis is a critical Smad4-independent regulator of keratinocyte proliferation and differentiation.

| S-EPMC2268163 | biostudies-literature

Topical hesperidin improves epidermal permeability barrier function and epidermal differentiation in normal murine skin.

Project description:Orange peel extract appears to exhibit beneficial effects on skin whitening, inflammation, UVB protection, as well as keratinocyte proliferation. In the present study, we determine whether topical hesperidin influences epidermal permeability barrier function and its underlying mechanisms. Hairless mice were treated topically with 2% hesperidin or 70% ethanol alone twice daily for 6 days. At the end of treatment, basal transepidermal water loss (TEWL) was measured 2 and 4 h post barrier disruption. Epidermal proliferation and differentiation were evaluated by immunohistochemical staining and Western blot analysis. Additionally, lamellar body density and secretion were assessed by electron microscopy. Although there were no significant differences in basal barrier function, in comparison with control animals, topical hesperidin significantly accelerated barrier recovery at both 2 and 4 h after acute barrier abrogation. Enhanced barrier function in hesperidin-treated skin correlated with stimulation of both epidermal proliferation and differentiation, as well as enhanced lamellar body secretion. These results indicate that topical hesperidin enhances epidermal permeability barrier homeostasis at least in part due to stimulation of epidermal proliferation, differentiation, as well as lamellar body secretion.

| S-EPMC3335754 | biostudies-literature

CIC is a critical regulator of neuronal differentiation.

Project description:Capicua (CIC), a member of the high mobility group-box (HMG-box) superfamily of transcriptional repressors, is frequently mutated in human oligodendrogliomas. However, its functions in brain development and tumorigenesis remain poorly understood. Here, we report that brain-specific deletion of Cic compromises developmental transition of neuroblasts to immature neurons in mouse hippocampus and compromises normal neuronal differentiation. Combined gene expression and ChIP-seq analyses identified VGF as an important CIC-repressed transcriptional surrogate involved in neuronal lineage regulation. Aberrant VGF expression promotes neural progenitor cell proliferation by suppressing their differentiation. Mechanistically, we demonstrated that CIC represses VGF expression by tethering SIN3-HDAC to form a transcriptional corepressor complex. Mass spectrometry analysis of CIC-interacting proteins further identified the BRG1-containing mSWI/SNF complex whose function is necessary for transcriptional repression by CIC. Together, this study uncovers a potentially novel regulatory pathway of CIC-dependent neuronal differentiation and may implicate these molecular mechanisms in CIC-dependent brain tumorigenesis.

| S-EPMC7253013 | biostudies-literature

BAF180 is a critical regulator of p21 induction and a tumor suppressor mutated in breast cancer.

Project description:Screening for tumor suppressor genes in breast cancer revealed multiple truncating mutations of PB1, which encodes the BAF180 subunit of the PBAF chromatin remodeling complex. Mutation was associated with loss of heterozygosity of the wild-type allele. BAF180 complementation of BAF180-mutant tumor cells caused G(1) arrest that was dependent on increased expression of the cyclin/cyclin-dependent kinase inhibitor p21/WAF1/CIP1. Endogenous wild-type BAF180 bound to the p21 promoter and was required for proper p21 expression and G(1) arrest after transforming growth factor-beta and gamma-radiation treatment. BAF180 thus functions on two tumor suppressor signaling pathways as a physiologic mediator of p21 expression. We conclude that BAF180 suppresses tumorigenesis, at least in part, through its ability to regulate p21.

| S-EPMC2915562 | biostudies-literature

Egr-5 is a post-mitotic regulator of planarian epidermal differentiation.

Project description:Neoblasts are an abundant, heterogeneous population of adult stem cells (ASCs) that facilitate the maintenance of planarian tissues and organs, providing a powerful system to study ASC self-renewal and differentiation dynamics. It is unknown how the collective output of neoblasts transit through differentiation pathways to produce specific cell types. The planarian epidermis is a simple tissue that undergoes rapid turnover. We found that as epidermal progeny differentiate, they progress through multiple spatiotemporal transition states with distinct gene expression profiles. We also identified a conserved early growth response family transcription factor, egr-5, that is essential for epidermal differentiation. Disruption of epidermal integrity by egr-5 RNAi triggers a global stress response that induces the proliferation of neoblasts and the concomitant expansion of not only epidermal, but also multiple progenitor cell populations. Our results further establish the planarian epidermis as a novel paradigm to uncover the molecular mechanisms regulating ASC specification in vivo.

| S-EPMC4716842 | biostudies-literature

Histamine suppresses epidermal keratinocyte differentiation and impairs skin barrier function in a human skin model.

Project description:BackgroundDefects in keratinocyte differentiation and skin barrier are important features of inflammatory skin diseases like atopic dermatitis. Mast cells and their main mediator histamine are abundant in inflamed skin and thus may contribute to disease pathogenesis.MethodsHuman primary keratinocytes were cultured under differentiation-promoting conditions in the presence and absence of histamine, histamine receptor agonists and antagonists. The expression of differentiation-associated genes and epidermal junction proteins was quantified by real-time PCR, Western blot, and immunofluorescence labeling. The barrier function of human skin models was tested by the application of biotin as tracer molecule.ResultsThe addition of histamine to human keratinocyte cultures and organotypic skin models reduced the expression of the differentiation-associated proteins keratin 1/10, filaggrin, and loricrin by 80-95%. Moreover, the addition of histamine to skin models resulted in the loss of the granular layer and thinning of the epidermis and stratum corneum by 50%. The histamine receptor H1R agonist, 2-pyridylethylamine, suppressed keratinocyte differentiation to the same extent as did histamine. Correspondingly, cetirizine, an antagonist of H1R, virtually abrogated the effect of histamine. The expression of tight junction proteins zona occludens-1, occludin, claudin-1, and claudin-4, as well as that of desmosomal junction proteins corneodesmosin and desmoglein-1, was down-regulated by histamine. The tracer molecule biotin readily penetrated the tight junction barrier of skin cultures grown in the presence of histamine, while their diffusion was completely blocked in nontreated controls.ConclusionsOur findings suggest a new mechanism by which mast cell activation and histamine release contribute to skin barrier defects in inflammatory skin diseases.

| S-EPMC3555427 | biostudies-literature

GEMC1 is a critical regulator of multiciliated cell differentiation.

Project description:The generation of multiciliated cells (MCCs) is required for the proper function of many tissues, including the respiratory tract, brain, and germline. Defects in MCC development have been demonstrated to cause a subclass of mucociliary clearance disorders termed reduced generation of multiple motile cilia (RGMC). To date, only two genes, Multicilin (MCIDAS) and cyclin O (CCNO) have been identified in this disorder in humans. Here, we describe mice lacking GEMC1 (GMNC), a protein with a similar domain organization as Multicilin that has been implicated in DNA replication control. We have found that GEMC1-deficient mice are growth impaired, develop hydrocephaly with a high penetrance, and are infertile, due to defects in the formation of MCCs in the brain, respiratory tract, and germline. Our data demonstrate that GEMC1 is a critical regulator of MCC differentiation and a candidate gene for human RGMC or related disorders.

| S-EPMC5207319 | biostudies-literature

Rab25 Deficiency Perturbs Epidermal Differentiation and Skin Barrier Function in Mice.

Project description:Rab25, a member of the Rab11 small GTPase family, is central to achieving cellular polarity in epithelial tissues. Rab25 is highly expressed in epithelial cells of various tissues including breast, vagina, cervix, the gastrointestinal tract, and skin. Rab25 plays key roles in tumorigenesis, mainly by regulating epithelial differentiation and proliferation. However, its role in skin physiology is relatively unknown. In this study, we demonstrated that Rab25 knock-out (KO) mice show a skin barrier dysfunction with high trans-epidermal water loss and low cutaneous hydration. To examine this observation, we investigated the histology and epidermal differentiation markers of the skin in Rab25 KO mice. Rab25 KO increased cell proliferation at the basal layer of epidermis, whereas the supra-basal layer remained unaffected. Ceramide, which is a critical lipid component for skin barrier function, was not altered by Rab25 KO in its distribution or amount, as determined by immunohistochemistry. Notably, levels of epidermal differentiation markers, including loricrin, involucrin, and keratins (5, 14, 1, and 10) increased prominently in Rab25 KO mice. In line with this, depletion of Rab25 with single hairpin RNA increased the expression of differentiation markers in a human keratinocyte cell line, HaCaT. Transcriptomic analysis of the skin revealed increased expression of genes associated with skin development, epidermal development, and keratinocyte differentiation in Rab25 KO mice. Collectively, these results suggested that Rab25 is involved in the regulation of epidermal differentiation and proliferation.

| S-EPMC6824620 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data