Steady-state and IL-1{alpha}-induced gene expression in wild-type and p38{alpha}-knockout HaCaT keratinocytes
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ABSTRACT: Keratinocytes, the epithelial cells of the skin, reprogram their gene expression and produce immune effector molecules when exposed to environmental and endogenous triggers of inflammation. It remains unclear how keratinocytes process physiologic signals generated during skin irritation and switch from a homeostatic to an inflammatory state. This gene expression analysis shows that the stress-activated protein kinase p38{alpha} is crucial for keratinocytes to prompt changes in their transcriptome upon cytokine stimulation.
Project description:Immortalized keratinocytes HaCaT is popular model for skin research (toxicity, irritation, allergic reactions or interaction of cells). They maintain stable keratinocyte phenotype and respond to keratinocyte differentiation stimuli. However, the programs of stratification and expression of differentiation markers in HaCaT keratinocytes are aberrant. HaCaT cells bear two mutant p53 alleles (R282Q and H179Y) which contain Gain-of-Function (GOV) mutations acquired as a result of spontaneous immortalization (mutp53). At the same time, mutp53 acts as a transcription factor, and also affects interaction of p63 protein with its transcription targets. It is known that proteins of the P53 family play an important role in regulating processes of proliferation and differentiation of human keratinocytes.At the same time, the role of mutp53 in these processes is not fully clear. We present data sets obtained as a result of high-performance proteomic analysis of immortalized HaCaT keratinocytes with p53 knockout in two different states: sub-confluent and confluent, which are characterized by different intensity of cell differentiation processes. As a protocol for proteomic profiling of cells, we used the approach of obtaining LC-MS/MS measurements followed by their processing with Progenesis LC-MS software (Nonlinear Dynamics Ltd.)
Project description:Keratinocytes are one of the major sources of chemokines in skin tissue. Therefore, we used keratinocytes HaCaT exposed to TNF-α/IFN-γ (10 ng/ml) to construct to establish an in vitro AD model. RNA from the control group and AD model group were performed RNA sequencing and KEGG analysis. The results showed that lots of cytokine-cytokine receptor pathways of HaCaT cells were activated in the AD model. Further analysis showed that chemokine expression was significantly up-regulated in the model group
Project description:Endogenous glucocorticoids (GCs) are pivotal in controlling inflammation. Keratinocyte-derived GCs contribute to local skin homeostasis as deletion of the GC-producing enzyme 11β-hydroxylase (Cyp11b1) in keratinocytes exacerbated skin inflammation. Since local tamoxifen-induced knockout (KO) induction may contribute to skin irritation, we implemented intraperitoneal injections to induce a systemic skin GC depletion preventing experimental skin irritation in order to reveal the importance of skin GC in steady-state. Both, local and systemic skin GC deficiency models exhibited reduced skin GC levels and increased migration of skin antigen-presenting cells to draining lymph nodes. However, systemic skin GC ablation did not result in pronounced skin inflammation as seen in local model. Interestingly, systemic skin GC deficiency elevated systemic inflammatory markers and provoked adrenal GC synthesis. RNA sequencing of keratinocytes revealed distinct gene expression patterns between local and systemic KOs. Local skin GC ablation showed a stronger inflammatory and apoptotic response, while systemic skin GC deficiency triggered several compensatory regulatory pathways, mitigating extensive skin inflammation. These findings underscore the critical role of local GCs in skin immune resilience against minor skin irritations and highlight the interplay between skin and adrenal GC levels.
Project description:Scaffold protein IQGAP3 mediates assembly of multiprotein complexes, orchestrating intracellular signaling pathways. Earlier we have found it to be overexpressed in lesional psoriatic skin. IQGAP3 is involved in cell proliferation and chemokine signaling that are key processes in psoriasis, so we decided to investigate the molecular basis of its role in psoriatic phenotype of keratinocytes. Transcriptome profiling of HaCaT keratinocytes allowed us to identify a wide range of psoriasis-associated pathways to be altered in IQGAP3-knockdown cells. NFkB signaling, EGFR signaling, p38/MAPK and ERK1/ERK2 activation, lipid metabolism and cytokine production as well as the response to the inflammatory cytokine stimulation were altered in the knockdown cells. Real-time analysis of cell growth revealed the alterations of proliferation and wound healing. The balance between proliferation and apoptosis of skin cells was altered, as well as the skin barrier functions and the production of IL-6 and IFNg. However, the diversity of the pathway alterations in the knockdown cells led us to the conclusion that IQGAP3 may not be the best target for the therapeutic inhibition to normalize the phenotype of keratinocytes in psoriasis.
Project description:Epidermal keratinocytes respond to extracellular influences by activating cytoplasmic signal transduction pathways that change the transcriptional profiles of affected cells. To define responses to two such pathways, p38 and ERK, we used SB203580 and PD98059 as specific inhibitors, and identified the regulated genes after 1, 4, 24 and 48 hrs, using Affymetrix’ Hu133Av2 microarrays. Additionally, we compared genes specifically regulated by p38 and ERKs with those regulated by JNK and by all three pathways simultaneously. We find that the p38 pathway induces the expression of extracellular matrix and proliferation-associated genes, while suppressing microtubule-associated genes; the ERK pathway induces the expression of nuclear envelope and mRNA splicing proteins, while suppressing steroid synthesis and mitochondrial energy production enzymes. Both pathways promote epidermal differentiation and induce feedback inactivation of MAPK signaling. c-FOS, SRY and N-Myc appear to be the principal targets of the p38 pathway, Elk-1 SAP1 and HLH2 of ERK, while FREAC-4, ARNT and USF are common to both. The results for the first time comprehensively define the genes regulated by the p38 and ERK pathways in epidermal keratinocytes and suggest a list of targets potentially useful in therapeutic interventions. Human epidermal keratinocytes are grown in Keratinocyte Serum-Free Medium (Gibco) supplemented with 0.05 mg/ml bovine pituitary extract, 2.5 ng/ml epidermal growth factor, 0.09 mM CalCl2 and 1% penicillin/streptomycin (KGM). They are switched to Keratinocyte Serum Free-Media (Gibco) supplemented only with 1% penicillin/streptomycin (KBM) 24 h prior to commencing experiments. A set is left as controls, others treated with 5 uM JNK inhibitor SP600125, 15 uM p38 inhibitor SB203580, or 50 um ERK inhibitor PD98059. Timecourse of treated and parellel control samples over a 48 hr period was performed.
Project description:Covering denuded dermal surface after injury requires migration, proliferation and differentiation of skin keratinocytes. To clarify the major traits controlling these intermingled biological events, we surveyed the genomic modifications occurring during the course of a scratch closure of cultured human keratinocytes. Using a DNA microarray approach, we report the identification of 161 new markers of epidermal repair. Expression data, combined with functional analysis performed with specific inhibitors of ERK, p38[MAPK] and PI3 kinases, demonstrate that kinase pathways exert very selective functions by precisely controlling the expression of specific genes. Inhibition of the ERK pathway totally blocks the wound closure and inactivates many early transcription factors and EGF-type growth factors. P38[MAPK] inhibition only delays “healing”, probably in line with the control of genes involved in the propagation of injury-initiated signalling. In contrast, PI3 kinase inhibition accelerates the scratch closure and potentiates the scratch-dependent stimulation of three genes related to epithelial cell transformation, namely HAS3, HBEGF and Ets1. Our results define in vitro human keratinocyte wound closure as a reparation process resulting from a fine balance between positive signals controlled by ERK and p38[MAPK], and negative ones triggered off by PI3 kinase. The perturbation of any of these pathways might lead to dysfunction in the healing process, as those observed in pathological wounding phenotypes, such as hypertrophic scars or keloids. Keywords: Transcriptome of healing keratinocytes
Project description:Epidermal keratinocytes respond to extracellular influences by activating cytoplasmic signal transduction pathways that change the transcriptional profiles of affected cells. To define responses to two such pathways, p38 and ERK, we used SB203580 and PD98059 as specific inhibitors, and identified the regulated genes after 1, 4, 24 and 48 hrs, using Affymetrix’ Hu133Av2 microarrays. Additionally, we compared genes specifically regulated by p38 and ERKs with those regulated by JNK and by all three pathways simultaneously. We find that the p38 pathway induces the expression of extracellular matrix and proliferation-associated genes, while suppressing microtubule-associated genes; the ERK pathway induces the expression of nuclear envelope and mRNA splicing proteins, while suppressing steroid synthesis and mitochondrial energy production enzymes. Both pathways promote epidermal differentiation and induce feedback inactivation of MAPK signaling. c-FOS, SRY and N-Myc appear to be the principal targets of the p38 pathway, Elk-1 SAP1 and HLH2 of ERK, while FREAC-4, ARNT and USF are common to both. The results for the first time comprehensively define the genes regulated by the p38 and ERK pathways in epidermal keratinocytes and suggest a list of targets potentially useful in therapeutic interventions.
Project description:We identified the transcription factor NRF3 as an important tumor-suppressing protein in the skin. To gain insight into the mechanisms of action of NRF3 in keratinocytes, we searched for NRF3 interactors in the SCC13 skin cancer and the immortalized non-tumorigenic HaCaT cell line using BioID interaction screening.
Project description:Cutaneous squamous cell carcinoma (cSCC) is the most prominent tumor of non-melanoma skin cancers and the most aggressive tumor among keratinocyte carcinoma of the skin, showing a high potential for local invasion and metastasis. The cSCC incidences increased dramatically in recent years and the disease occurs more commonly than any other malignancy. The secretome of cancer cells is currently the focus of many studies in order to identify new marker proteins for different types of cancer and to investigate its influence on the tumor microenvironment. In our study we evaluated whether the secretome of cSCC cells has an impact on keratinocytes, the surrounding tissue cells of cSCC. Therefore, we analyzed and compared the secretome of human A431 cancer cells and of HaCaT keratinocytes by mass spectrometry.