Project description:Laser capture microdissection coupled with microarray genes expression analysis were utilized in order to elucidate the regulatory networks active in epithelial cells of the neonatal and adult mouse uterus. Genes predominantly expressed in the glandular epithelium (GE) in the neonatal or adult uterus were determined by comparing transcripts in the isolated samples of luminal epithelium (LE) and GE from postnatal day (PD) 10, day of psudopregnancy (DOPP) 2.5 or DOPP 3.5 uteri (n=2/cell type/day).
Project description:The mammary gland epithelium is composed of basal cells (BC) and luminal cells (LC). Lineage tracing demonstrates that many glandular epithelia initially develop from multipotent basal stem cells (BaSCs) that are replaced in adult life by distinct pool of unipotent stem cells. However, adult unipotent BaSC can reactivate multipotency and give rise to LCs upon transplantation or oncogene expression, demonstrating the important plasticity of BaSCs in regenerative and pathological conditions, and suggesting that an active mechanism restricts multipotency in BaSCs during physiological conditions. Here, we assess whether basal and luminal cell-cell communication restricts multipotency in glandular epithelia.
Project description:Glandular epithelia including the mammary gland (MG) and the prostate are composed of basal cells (BC) and luminal cells (LC). Lineage tracing demonstrates that many glandular epithelia initially develop from multipotent basal stem cells (BaSCs) that are replaced in adult life by distinct pool of unipotent stem cells (SCs). However, adult unipotent BaSC can reactivate multipotency and give rise to LCs upon transplantation or oncogene expression, demonstrating the important plasticity of BaSCs in regenerative and pathological conditions, and suggesting that an active mechanism restricts multipotency in BaSCs during physiological conditions. The nature of this mechanism is currently unknown. Here, we assess whether basal and luminal cell-cell communication restricts multipotency in glandular epithelia. To this end, we performed lineage tracing of BCs together with the ablation of LCs in different adult glandular epithelia including MG, prostate, sweat glands and salivary glands and assessed the fate of BaSCs overtime. Interestingly, ablation of LCs reactivated multipotency in unipotent adult BaSCs from multiple epithelia. To understand the molecular mechanisms that controls multipotency in adult BaSCs, we performed population bulk-RNA-seq and single cell RNA-seq of FACS isolated adult mammary epithelial cells after LC ablation. Upon LC ablation, adult BCs activate a hybrid basal and luminal differentiation program before giving rise to LC, reminiscent of the genetic program that regulate multipotency during embryonic development. Different signaling pathways including Notch, Wnt and Egfr were activated in BaSC and their progeny following LC ablation and blocking these pathways inhibited adult BC multipotency. Altogether, our study demonstrates that heterotypic LC and BC communication is essential to maintain lineage fidelity in glandular epithelial SC during homeostasis and uncovers the lineage trajectory and signaling pathways that promote multipotency during tissue repair.
Project description:Glandular epithelia, including mammary gland (MG) and prostate, are composed of luminal and basal cells. During embryonic development, glandular epithelia arise from multipotent stem cells (SCs) giving rise to basal and luminal cells. However, these multipotent SCs are replaced after birth by unipotent basal and unipotent luminal SCs. Different conditions, such as basal cell transplantation, luminal cell ablation, and oncogene expression, can reinduce multipotency in adult basal SC (BaSCs) of different glandular epithelia. The mechanisms regulating the reactivation of multipotency in BaSCs are incompletely understood. Here, we compared the transcriptional signature of BaSCs from MG and prostate in different conditions associated with multipotency in adult mice and uncovered that Collagen I expression was commonly upregulated across the different conditions associated with multipotency. Using MG and prostate organoids, we demonstrated that increasing collagen concentration or stiffness of the extracellular matrix (ECM) promote BaSC multipotency. Single cell RNA-seq of MG organoids in the presence of high concentration of Collagen I or in a stiffer ECM activate a hybrid bipotent state and uncovered a gene signature and signaling pathways associated with bipotent BaSCs. Finally, we demonstrated the importance of 1integrin/FAK/AP-1 axis in the regulation of BaSC multipotency in response to Col1 signaling and ECM stiffness. Altogether our study uncovers the key role of Collagen signaling and ECM stiffness in the regulation of multipotency in glandular epithelia.
Project description:Glandular epithelia, including mammary gland (MG) and prostate, are composed of luminal and basal cells. During embryonic development, glandular epithelia arise from multipotent stem cells (SCs) giving rise to basal and luminal cells. However, these multipotent SCs are replaced after birth by unipotent basal and unipotent luminal SCs. Different conditions, such as basal cell transplantation, luminal cell ablation, and oncogene expression, can reinduce multipotency in adult basal SC (BaSCs) of different glandular epithelia. The mechanisms regulating the reactivation of multipotency in BaSCs are incompletely understood. Here, we compared the transcriptional signature of BaSCs from MG and prostate in different conditions associated with multipotency in adult mice and uncovered that Collagen I expression was commonly upregulated across the different conditions associated with multipotency. Using MG and prostate organoids, we demonstrated that increasing collagen concentration or stiffness of the extracellular matrix (ECM) promote BaSC multipotency. Single cell RNA-seq of MG organoids in the presence of high concentration of Collagen I or in a stiffer ECM activate a hybrid bipotent state and uncovered a gene signature and signaling pathways associated with bipotent BaSCs. Finally, we demonstrated the importance of 1integrin/FAK/AP-1 axis in the regulation of BaSC multipotency in response to Col1 signaling and ECM stiffness. Altogether our study uncovers the key role of Collagen signaling and ECM stiffness in the regulation of multipotency in glandular epithelia.
Project description:PURPOSE: To provide a detailed gene expression profile of the normal postnatal mouse cornea. METHODS: Serial analysis of gene expression (SAGE) was performed on postnatal day (PN)9 and adult mouse (6 week) total corneas. The expression of selected genes was analyzed by in situ hybridization. RESULTS: A total of 64,272 PN9 and 62,206 adult tags were sequenced. Mouse corneal transcriptomes are composed of at least 19,544 and 18,509 unique mRNAs, respectively. One third of the unique tags were expressed at both stages, whereas a third was identified exclusively in PN9 or adult corneas. Three hundred thirty-four PN9 and 339 adult tags were enriched more than fivefold over other published nonocular libraries. Abundant transcripts were associated with metabolic functions, redox activities, and barrier integrity. Three members of the Ly-6/uPAR family whose functions are unknown in the cornea constitute more than 1% of the total mRNA. Aquaporin 5, epithelial membrane protein and glutathione-S-transferase (GST) omega-1, and GST alpha-4 mRNAs were preferentially expressed in distinct corneal epithelial layers, providing new markers for stratification. More than 200 tags were differentially expressed, of which 25 mediate transcription. CONCLUSIONS: In addition to providing a detailed profile of expressed genes in the PN9 and mature mouse cornea, the present SAGE data demonstrate dynamic changes in gene expression after eye opening and provide new probes for exploring corneal epithelial cell stratification, development, and function and for exploring the intricate relationship between programmed and environmentally induced gene expression in the cornea. Keywords: other
Project description:The uterus is an essential organ for reproduction in mammals, however the cellular and molecular mechanisms that direct its development remain insufficiently understood. To fill this knowledge gap, the epithelium of the neonatal mouse uterus was isolated and subjected to single cell transcriptome (scRNA-seq) analysis. Substantial differences in transcriptional profiles and cell types were evident as the epithelium developed from postnatal days 1 to 15. Both the undifferentiated epithelium and determined luminal epithelium were heterogeneous and contained several different cell clusters. Novel glandular epithelial-specific genes (Gas6 and Cited4) were validated by in situ hybridization during uterine development. Trajectory analyses provided a framework for understanding epithelium maturation and differentiation of the glandular epithelium. A candidate set of transcription factors and gene regulatory networks were identified that regulate epithelium lineage specification and morphogenesis. This atlas provides foundational insights important for future mechanistic studies focused on uterine epithelium morphogenesis during the critical window of postnatal development.
Project description:Developmental exposure to non-mutagenic environmental factors can contribute to cancer risk, but the underlying mechanisms are not understood. We used a mouse model of endometrial adenocarcinoma that results from brief developmental exposure to an estrogenic chemical, diethylstilbestrol (DES), to determine causative factors. Single cell RNA sequencing and spatial transcriptomics of adult uteri revealed new markers of uterine epithelial stem cells, identified luminal and glandular progenitor cells, and defined a glandular epithelial differentiation trajectory. Neonatal DES exposure disrupted uterine epithelial differentiation, resulting in widespread activation of Wnt signaling and a failure to generate epithelial stem cells or distinguishable glandular and luminal epithelial cells. The endometrial stromal cells activated inflammatory signals and oxidative stress. Together, these changes activated PI3K/AKT signaling to drive malignant transformation. These findings explain how human cancers, which are often associated with abnormal activation of PI3K/AKT signaling, could result from exposure to environmental insults during development.
Project description:Purpose:The endometrium layer comprises of luminal and glandular epithelia that both develop from the same simple layer of fetal uterine epithelia. Mechanisms of uterine epithelial progenitor self-renewal and differentiation are unclear. Methods: This study aims to systematically analyze the molecular and cellular mechanisms of uterine epithelia development by single cell RNA-Seq Results: An integrated set of single cell transcriptomic data of uterine epithelial progenitors and their differentiated progenies is provided. Additionally, the unique molecular signatures of these cells, characterized by sequential up-regulation of specific epigenetic and metabolic activities, and activation of unique signaling pathways and transcription factors, were also investigated. Finally, a unique subpopulation of early progenitor, as well as differentiated luminal and glandular lineages were identified. A complex cellular hierarchy of uterine epithelia development was thus delineated. Conclusions: Our study therefore systematically decoded molecular markers and cellular program of uterine epithelia development that would shed lights on uterine developmental biology.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.