Project description:During epithelial tissue morphogenesis, developmental progenitor cells undergo dynamic adhesive and cytoskeletal remodeling to trigger proliferation and migration. Transcriptional mechanisms that restrict such mild form of epithelial plasticity to maintain lineage-restricted differentiation in committed epithelial tissues are poorly understood. Here we report that simultaneous ablation of transcriptional repressor-encoding Ovol1 and Ovol2 results in expansion and blocked terminal differentiation of embryonic epidermal progenitor cells. Conversely, mice overexpressing Ovol2 in their skin epithelia exhibit precocious differentiation accompanied by smaller progenitor cell compartments. We show that Ovol1/2-deficient epidermal cells fail to undertake alpha-catenin–driven actin cytoskeletal reorganization and adhesive maturation, and exhibit changes that resemble epithelial-to-mesenchymal transition (EMT). Remarkably, these alterations as well as defective terminal differentiation are reversed upon depletion of EMT-promoting transcriptional factor Zeb1. Collectively, our findings reveal Ovol-Zeb1-a-catenin sequential repression and highlight novel functions of Ovol as gatekeepers of epithelial adhesion and differentiation by inhibiting progenitor-like traits and epithelial plasticity. Skin from control and Ovol2 overexpression (Ovol2 BT) were physically isolated for RNA extraction and hybridization on Affymetrix microarrays. In order to identify primary changes, we analyzed skin from E16.5 mice, when morphological differences between control and Ovol2 overexpression were still minimal.
Project description:During epithelial tissue morphogenesis, developmental progenitor cells undergo dynamic adhesive and cytoskeletal remodeling to trigger proliferation and migration. Transcriptional mechanisms that restrict such mild form of epithelial plasticity to maintain lineage-restricted differentiation in committed epithelial tissues are poorly understood. Here we report that simultaneous ablation of transcriptional repressor-encoding Ovol1 and Ovol2 results in expansion and blocked terminal differentiation of embryonic epidermal progenitor cells. Conversely, mice overexpressing Ovol2 in their skin epithelia exhibit precocious differentiation accompanied by smaller progenitor cell compartments. We show that Ovol1/2-deficient epidermal cells fail to undertake alpha-catenin–driven actin cytoskeletal reorganization and adhesive maturation, and exhibit changes that resemble epithelial-to-mesenchymal transition (EMT). Remarkably, these alterations as well as defective terminal differentiation are reversed upon depletion of EMT-promoting transcriptional factor Zeb1. Collectively, our findings reveal Ovol-Zeb1-a-catenin sequential repression and highlight novel functions of Ovol as gatekeepers of epithelial adhesion and differentiation by inhibiting progenitor-like traits and epithelial plasticity. Skin from control and Ovol2 overexpression (Ovol2 BT) were physically isolated for RNA extraction and hybridization on Affymetrix microarrays. In order to identify changes in differentiation of the epidermis, we analyzed skin from E17.5 mice, when differentiation of the epidermis was more advanced.
Project description:Epithelial cells possess remarkable plasticity, having the ability to become mesenchymal cells through alterations in adhesion and motility (epithelial-to-mesenchymal transition or EMT). However, it is still unknown whether and how epithelial plasticity is kept in check in epithelial cells during development. Here we show that restricting the EMT of mammary epithelial cells by transcription factor Ovol2 is required for proper morphogenesis and regeneration. Deletion of Ovol2 blocks mammary ductal morphogenesis, depletes stem/progenitor cell reservoirs, and leads epithelial cells to undergo EMT in vivo to become non-epithelial cell types. Ovol2 directly represses myriad EMT inducers and its absence switches response to TGF-beta from growth arrest to EMT. Furthermore, forced expression of the repressor isoform of Ovol2 is able to reprogram metastatic breast cancer cells from a mesenchymal to an epithelial state. Our findings underscore the critical importance of exquisitely regulating epithelial plasticity in development and cancer. Refer to individual Series
Project description:Cleft palate is a common congenital anomaly with a live birth prevalence estimated to be 1:2500 live births, that results from failure of growth, elevation, adhesion and/or fusion of the palatal shelves during embryogenesis. Mutations in the gene encoding the transcription factor p63 result in cleft palate in humans and mice. To study the roles of P63 in periderm migration and medial edge epithelia in mice sub-mucous cleft palate, ÎNp63alpha was ectopically expressed in the palatal epithelia using a transgenic approach.
Project description:We identify numerous miR-203 in vivo targets that are highly enriched for the promotion of cell cycle and cell division. Importantly, individual targets including p63, Skp2 and Msi2 play distinct roles downstream of miR-203 to regulate the cell cycle and long-term proliferation. Together, our findings reveal rapid and widespread impact of miR-203 on the self-renewal program during the epidermal differentiation and provide mechanistic insights for the potent role of miR-203 where coordinated repression of multiple targets is required for the function of this miRNA. We used microarrays to measure transcriptome changes upon miR-203's induction in mouse skin and identified new targets of miR-203. We use two pairs of biological duplicates to perform the microarray analysis from the epidermal samples harvested from K14-rtTA/TRE-miR-203/K14-H2BGFP (DP) and TRE-miR-203/K14-H2BGFP (SP) littermates at P4, 24h after the Dox injection.
Project description:During epithelial tissue morphogenesis, developmental progenitor cells undergo dynamic adhesive and cytoskeletal remodeling to trigger proliferation and migration. Transcriptional mechanisms that restrict such mild form of epithelial plasticity to maintain lineage-restricted differentiation in committed epithelial tissues are poorly understood. Here we report that simultaneous ablation of transcriptional repressor-encoding Ovol1 and Ovol2 results in expansion and blocked terminal differentiation of embryonic epidermal progenitor cells. Conversely, mice overexpressing Ovol2 in their skin epithelia exhibit precocious differentiation accompanied by smaller progenitor cell compartments. We show that Ovol1/2-deficient epidermal cells fail to undertake alpha-catenin–driven actin cytoskeletal reorganization and adhesive maturation, and exhibit changes that resemble epithelial-to-mesenchymal transition (EMT). Remarkably, these alterations as well as defective terminal differentiation are reversed upon depletion of EMT-promoting transcriptional factor Zeb1. Collectively, our findings reveal Ovol-Zeb1-a-catenin sequential repression and highlight novel functions of Ovol as gatekeepers of epithelial adhesion and differentiation by inhibiting progenitor-like traits and epithelial plasticity. Isolated keratinocytes from control, Ovol1 knockout and Ovol1/2 double knockout were physically isolated for RNA extraction and hybridization on Affymetrix microarrays. In order to identify primary changes, we isolated the keratinocytes from mouse skin and allowed them to grow in culture for 2-5 days.
Project description:During epithelial tissue morphogenesis, developmental progenitor cells undergo dynamic adhesive and cytoskeletal remodeling to trigger proliferation and migration. Transcriptional mechanisms that restrict such mild form of epithelial plasticity to maintain lineage-restricted differentiation in committed epithelial tissues are poorly understood. Here we report that simultaneous ablation of transcriptional repressor-encoding Ovol1 and Ovol2 results in expansion and blocked terminal differentiation of embryonic epidermal progenitor cells. Conversely, mice overexpressing Ovol2 in their skin epithelia exhibit precocious differentiation accompanied by smaller progenitor cell compartments. We show that Ovol1/2-deficient epidermal cells fail to undertake alpha-catenin–driven actin cytoskeletal reorganization and adhesive maturation, and exhibit changes that resemble epithelial-to-mesenchymal transition (EMT). Remarkably, these alterations as well as defective terminal differentiation are reversed upon depletion of EMT-promoting transcriptional factor Zeb1. Collectively, our findings reveal Ovol-Zeb1-a-catenin sequential repression and highlight novel functions of Ovol as gatekeepers of epithelial adhesion and differentiation by inhibiting progenitor-like traits and epithelial plasticity. Isolated keratinocytes from control, Ovol1 knockout and Ovol1/2 double knockout were physically isolated for RNA extraction and hybridization on Affymetrix microarrays. In order to identify differentiation changes, we isolated the keratinocytes from mouse skin and allowed them to grow in culture for 2-5 days, then added calcium and allowed them to grow another 3-5 days.
Project description:We identified 201 genes that are consistently upregulated more than 20%, and 108 genes that are consistently downregulated more than 20% in the miR-205 KO samples in two sets of biological duplicates. We used microarrays to measure transcriptome changes upon knockout of miR-205 in hair follicle stem cells of mouse skin and identified new targets of miR-205. We isolated the HFSCs from WT and miR-205 KO skin at P4 and compare mRNA expression by microarray analysis
Project description:Epithelial cells possess remarkable plasticity, having the ability to become mesenchymal cells through alterations in adhesion and motility (epithelial-to-mesenchymal transition or EMT). Recent studies suggest that EMT endows differentiated epithelial cells with stem cell traits, posing the interesting question of how epithelial plasticity is properly restricted to ensure epithelial differentiation during tissue morphogenesis. Here we identify zinc-finger transcription factor Ovol2 as a key suppressor of EMT of mammary epithelial cells. Epithelia-specific deletion of Ovol2 completely arrests mammary ductal morphogenesis, and depletes epithelial stem/progenitor cell reservoirs. Further, Ovol2-deficient epithelial cells undergo EMT in vivo to become non-epithelial cell types, and that Ovol2 directly represses key EMT inducers such as Zeb1 and regulates stem/progenitor cell responsiveness to TGF-beta. We also provide evidence for a suppressive role of Ovol2 in breast cancer progression. Our findings underscore the critical importance of exquisitely regulating epithelial plasticity to balance stemness with epithelial differentiation in development and cancer. TEBs from control and conditional Ovol2-knockout mammary glands were physically isolated for RNA extraction and hybridization on Affymetrix microarrays. In order to identify primary changes, we analyzed TEBs from 24-25-day-old mice, when morphological differences between control and Ovol2 SSKO were still minimal.
Project description:Increasing evidence suggests that microRNAs may play important roles in regulating self-renewal and differentiation in mammalian stem cells (SCs). Here, we explore this issue in skin. We first characterize microRNA expression profiles of skin SCs versus their committed proliferative progenies and identify a microRNA subset associating with “stemness”. Of these, miR-125b is dramatically downregulated in early SC-progeny. We engineer an inducible mice system and show that when miR-125b is sustained in SC-progenies, tissue balance is reversibly skewed towards stemness at the expense of epidermal, oil-gland and HF differentiation. Using gain-and-loss of function in vitro, we further implicate miR-125b as a repressor of SC differentiation. In vivo, transcripts repressed upon miR-125b induction are enriched >700% for predicted miR-125b targets normally downregulated upon SC-lineage commitment. We verify some of these miR-125b targets, and show that Blimp1 and VDR in particular can account for many tissue imbalances we see when miR-125b is deregulated. We used microarrays to compare the global miRNA expression profile of P4 stage hair follicle ORS cells from DTG (K14-rtTA,TRE-miR-125b) and control littermates. Hair follicle cells were isolated from P4 Backskin (Dox since P3 for 24hrs) of DTG (K14-rtTA/TRE-miR-125b/K14-H2BGFP), TRE (TRE-miR-125b/K14-H2BGFP), KrtA (K14-rtTA/K14-H2BGFP) as following: interfollicular epidermis sheet was pealed from hair follicle & dermis after dispase treatment.The hair follicle & dermis were first digested by collagenase (Sigma). Intact hair follicles were separated from dermal cells by low speed spinning (20g). The hair follicles were then digested by Trypsin and filtered by 40 µm cell strainers. The isolated hair follicle cells were FACS sorted. During FACS, cells were first gated against CD34 (endothelial cells), CD45 (immune cells), CD114 (melanocytes) and DAPI (dead cells). ORS cells were sorted from the remaining cells as α6HiGFPHi.