Project description:Sphingosine 1-phosphate (S1P) is a bioactive lipid whose levels are tightly regulated by its synthesis and degradation. Intracellularly, S1P is dephosphoryled by the actions of two S1P-specific phosphatases, sphingosine 1-phosphate phosphatase 1 and 2. To identify the physiologic functions of S1P phosphatase 1, we have studied mice with its gene, Sgpp1, deleted. Sgpp1-/- mice appeared normal at birth but during the first week of life, they exhibited stunted growth, suffered desquamation, and most died before weaning. Interestingly, the epidermal permeability barrier developed normally during embryogenesis. Sgpp1 -/- pups and surviving adults exhibited epidermal hyperplasia and abnormal expression of keratinocyte differentiation markers. Keratinocytes isolated from Sgpp1 -/- skin had increased intracellular S1P levels, and expressed a gene expression profile that indicated enhanced differentiation. The results reveal S1P metabolism as a regulator of keratinocyte differentiation and epidermal homeostasis. Comparison of KO vs. WT with five replications per treatment sample
Project description:Sphingosine 1-phosphate (S1P) is a bioactive lipid whose levels are tightly regulated by its synthesis and degradation. Intracellularly, S1P is dephosphoryled by the actions of two S1P-specific phosphatases, sphingosine 1-phosphate phosphatase 1 and 2. To identify the physiologic functions of S1P phosphatase 1, we have studied mice with its gene, Sgpp1, deleted. Sgpp1-/- mice appeared normal at birth but during the first week of life, they exhibited stunted growth, suffered desquamation, and most died before weaning. Interestingly, the epidermal permeability barrier developed normally during embryogenesis. Sgpp1 -/- pups and surviving adults exhibited epidermal hyperplasia and abnormal expression of keratinocyte differentiation markers. Keratinocytes isolated from Sgpp1 -/- skin had increased intracellular S1P levels, and expressed a gene expression profile that indicated enhanced differentiation. The results reveal S1P metabolism as a regulator of keratinocyte differentiation and epidermal homeostasis.
2013-08-09 | GSE40368 | GEO
Project description:Sphingosine 1-phosphate receptor 2 is central to maintaining epidermal barrier homeostasis
Project description:Sphingosine-1-phosphate (S1P) is a sphingolipid metabolite that regulates basic cell functions through metabolic and signaling pathways. Intracellular metabolism of S1P is controlled, in part, by two homologous S1P phosphatases, 1 and 2, which are encoded by Sgpp1 and Sgpp2, respectively. S1P phosphatase activity is needed for efficient recycling of sphingosine into the sphingolipid synthesis pathway. S1P phosphatase 1 is important for skin homeostasis, but little is known about the functional role of S1P phosphatase 2. To identify the functions of S1P phosphatase 2 in vivo, we studied mice with the Sgpp2 gene deleted. In contrast to Sgpp1-/- mice, Sgpp2-/- mice had normal skin and were viable into adulthood. Unexpectedly, WT mice expressed Sgpp2 mRNA at high levels in pancreatic islets when compared with other tissues. Sgpp2-/- mice had normal blood insulin levels and pancreatic islet size; however, Sgpp2-/- mice treated with a high-fat diet (HFD) had significantly lower blood insulin levels and smaller pancreatic islets compared with WT mice. The smaller islets in the HFD-treated Sgpp2-/- mice had a significantly lower adaptive B-cell proliferation rate in response to the diet compared with HFD-treated WT mice. Importantly, B-cells from Sgpp2-/- mice fed a normal diet showed significantly increased expression of proteins characteristic of the endoplasmic reticulum (ER) stress response compared with B-cells from WT mice. Our results suggest that Sgpp2 deletion causes B-cell ER stress, which is a known cause of B-cell dysfunction, and reveal a novel juncture in the sphingolipid recycling pathway that could impact the development of diabetes. Three replications of Mouse (WT vs KO) that were treated with with Normal and HFD foods.
Project description:Progenitor cells at the basal layer of skin epidermis play an essential role in maintaining tissue homeostasis and enhancing wound repair in skin. The proliferation, differentiation, and cell death of epidermal progenitor cells have to be delicately regulated, as deregulation of this process can lead to many skin diseases, including skin cancers. However, the underlying molecular mechanisms involved in skin homeostasis remain poorly defined. In this study, with quantitative proteomics approach, we identified an important interaction between KDF1 (Keratinocyte Differentiation Factor 1) and IKKα (IκB kinase α) in differentiating skin keratinocytes. Ablation of either KDF1 or IKKα in mice leads to similar but striking abnormalities in skin development, particularly in skin epidermal differentiation. With biochemical and mouse genetics approach, we further demonstrate that the interaction of IKKα and KDF1 is essential for epidermal differentiation. To probe deeper into the mechanisms, we find that KDF1 associates with a deubiquitinating protease, USP7 (Ubiquitin Specific Peptidase 7), and KDF1 can regulate skin differentiation through deubiquitination and stabilization of IKKα. Taken together, our study unravels an important molecular mechanism underlying skin tissue homeostasis and epidermal differentiation.
Project description:Several long non-coding RNAs (lncRNAs) act as regulators of cellular homeostasis; however, few of these molecules were functionally characterized in a mature human tissue environment. Here, we report that the lncRNA LINC00941 is a crucial regulator of human epidermal homeostasis. LINC00941 is enriched in progenitor keratinocytes and acts as a repressor of keratinocyte differentiation. Furthermore, LINC00941 represses SPRR5, a previously uncharacterized molecule, which functions as an essential positive regulator of keratinocyte differentiation. Interestingly, 54.8% of genes repressed in SPRR5 deficient epidermal tissue are induced in LINC00941 depleted organotypic epidermis, suggesting a common mode of action for both molecules.
Project description:Numerous long non-coding RNAs (lncRNAs) were shown to have functional impact on cellular processes, such as human epidermal homeostasis, but for only a few the mode of action has been elucidated. Here, we report that lncRNA LINC00941 controls keratinocyte differentiation on a global level through association with the MTA2/NuRD complex, one of the major chromatin remodelers in cells. LINC00941 was found to interact with NuRD-associated MTA2, suppressing the expression of the transcription factor EGR3, a regulator of epidermal differentiation. Both LINC00941 and the MTA2/NuRD complex are enriched in non-differentiated keratinocytes and repress the expression of differentiation genes through epigenetic silencing of EGR3, consequentially preventing premature differentiation of human progenitor cells.
Project description:The Aryl Hydrocarbon Receptor (AHR) is an environmental sensor and an indispensable regulator of epithelial homeostasis. To investigate AHR-mediated gene regulation, we performed a comprehensive transcriptomic and epigenomic analysis using human primary epidermal keratinocytes. Our results showed that AHR activation led to the induction of canonical transcription factors involved in epidermal differentiation as an early response, i.e. Transcription Factor AP-2α (TFAP2A), while epidermal differentiation-related genes, such as filaggrin and keratins, were activated as late responsive genes. The identified AHR-TFAP2A axis and its role in keratinocyte terminal differentiation was confirmed through AHR and TFAP2A knockout using CRISPR/Cas9. Our findings demonstrate that AHR regulates epidermal differentiation through the transient activation of specific transcription factors, such as TFAP2A, in response to environmental cues. The herein identified AHR-TFAP2A axis provides a promising target for the treatment of diseases related to skin barrier dysfunction.
Project description:The Aryl Hydrocarbon Receptor (AHR) is an environmental sensor and an indispensable regulator of epithelial homeostasis. To investigate AHR-mediated gene regulation, we performed a comprehensive transcriptomic and epigenomic analysis using human primary epidermal keratinocytes. Our results showed that AHR activation led to the induction of canonical transcription factors involved in epidermal differentiation as an early response, i.e. Transcription Factor AP-2α (TFAP2A), while epidermal differentiation-related genes, such as filaggrin and keratins, were activated as late responsive genes. The identified AHR-TFAP2A axis and its role in keratinocyte terminal differentiation was confirmed through AHR and TFAP2A knockout using CRISPR/Cas9. Our findings demonstrate that AHR regulates epidermal differentiation through the transient activation of specific transcription factors, such as TFAP2A, in response to environmental cues. The herein identified AHR-TFAP2A axis provides a promising target for the treatment of diseases related to skin barrier dysfunction.