Project description:The sensitive central nervous system is protected from potentially toxic components in the circulation by a semi-permeable interface, the blood brain barrier (BBB). This barrier is tightly regulated by several stromal cell types, however in certain regions of the brain it requires distinct properties. In particular, two of these regions, the choroid plexus and the pituitary gland are considered differentially permeable compared to other regions. Perivascular mesenchymal progenitors are intimately associated with endothelium and are therefore key participants in the regulation of the BBB. Using a mesenchymal progenitor specific lineage tracing tool, gene expression in this population from the choroid plexus and pituitary gland was profiled at the single cell level to investigate the genetic programs that allow these regions to maintain their respective specific pervious properties.
Project description:During mouse embryonic development, the limbs emanate from primordial buds of lateral plate mesoderm as proliferating mesenchymal cells cause protrusions of the overlying ectoderm. As the bud expands, several populations of cells are thought to migrate into the emerging limb and contribute to various specialized structures therein. A unique subset has been identified among the migrating populations that contributes to enduring stromal compartments in various tissues and is responsible for aspects of secondary morphogenesis including the formation of entheses throughout the limb. Using a lineage tracing tool, this population was sampled at various stages along the developmental continuum and gene expression was profiled at the single cell level to determine the fate and function of this cell subtype and the genetic programs involved.
Project description:During mouse embryonic development, the limbs emanate from primordial buds of lateral plate mesoderm as proliferating mesenchymal cells cause protrusions of the overlying ectoderm. As the bud expands, several populations of cells are thought to migrate into the emerging limb and contribute to various specialized structures therein. A unique subset has been identified among the migrating populations that contributes to enduring stromal compartments in various tissues and is responsible for aspects of secondary morphogenesis including the formation of entheses throughout the limb. Using a lineage tracing tool, this population was sampled at various stages along the developmental continuum and chromatin accessibility was profiled at the single cell level to determine the fate and function of this cell subtype and the epigenetic programs involved.
Project description:After tissue injury mesenchymal progenitor subsets undergo a transient proliferative expansion, morphological transition and migration from their perivascular niche. Some of these subsets contribute enduring populations to connective tissue structures adjacent to muscle. To gain insights into gene accessibility to complement the single cell RNA seq expression data previously obtained and to uncover the lineage potential of MPs in this context, tdTomato positive cells were profiled by single cell ATAC sequencing.
Project description:Despite their key role in immunity our understanding of primary and secondary lymphoid stromal cell heterogeneity and ontogeny remains limited. Here, using genome-wide expression profiling and phenotypic and localization studies, we identify a functionally distinct subset of BP3-PDPN+PDGFRβ+/α+CD34+ stromal adventitial cells in both lymph nodes and thymus that is located within the perivascular niche surrounding PDPN-PDGFRβ+/α-Esam-1+ITGA7+ pericytes. In re-aggregate organ grafts adult CD34+ adventitial cells gave rise to multiple thymic and lymph node mesenchymal subsets including pericytes, FRC-, MRC- and FDC-like cells, the development of which was lymphoid environment dependent. During thymic ontogeny pericytes developed from a transient population of BP3-PDPN+PDGFRβ+/α+CD34-/lo anlage-seeding progenitors that subsequently up-regulated CD34 and we provide evidence suggesting that similar embryonic progenitors give rise to lymph node mesenchymal subsets. These findings extend the current understanding of lymphoid mesenchymal cell heterogeneity and highlight a role of the CD34+ vascular adventitia as a potential ubiquitous source of lymphoid stromal precursors in postnatal tissues. To comprehensively study the differences and similarities between mesenchymal stromal subsets in the thymus and lymph nodes, global gene expression analysis was performed on sorted PDPN-, BP-3-PDPN+ and BP-3+PDPN+ PDGFRb+ lymph node mesenchymal cells (LNMC) as well as PDPN- and BP-3-PDPN+ PDGFRb+ thymic mesenchymal cells (TMC) from 2 w old mice by microarray. Total RNA was prepared from TMC and LNMC (pooled inguinal, brachial and axillary LN) subsets sorted from 3 (TMC) and 10-11 (LNMC) 2 weeks old mice per experiment. Isolated RNA from 3 individual experiments was amplified and prepared for hybridization to the Affymetrix Mouse Gene 1.1 ST Array at a genomics core facility: Center of Excellence for Fluorescent Bioanalytics (KFB, University of Regensburg, Germany)