Project description:iPSC-derived microglia expressing the wildtype, G795A, or G795C CSF1R variants were generated in vitro and treated with either DMSO or Plexxicon 5622 in order to compare the gene expression differences exising between genotypes at baseline or following CSF1R inhibtion.
Project description:iPSC-derived hematopoietic progenitor cells expressing either the wildtype or G795A CSF1R variant were xenotransplanted into neonatal mice and subsequently aged for two months to compare in vivo gene expression differences between the two CSF1R genotypes.
Project description:Microglia are important immune cells in the central nervous system (CNS). Dysfunctions of gene-deficient microglia contribute to the development and progression of multiple CNS diseases. Microglia replacement by nonself cells has been proposed to treat microglia associated disorders. However, most of attempts are failed due to low replacement efficiencies, such as with the traditional bone marrow transplantation approach. In this study, we develop three efficient strategies for microglia replacement: microglia replacement by bone marrow transplantation (mrBMT), microglia replacement by peripheral blood (mrPB) and microglia replacement by microglia transplantation (mrMT). mrBMT and mrPB allow microglia-like cells to efficiently replace resident microglia in the whole CNS. On the other hand, mrMT achieves microglia replacement in brain regions of interest. In summary, the present study offers effective tactics for microglia replacement with diverse application scenarios, which potentially opens up a window on treating microglia-associated CNS disorders.
Project description:Purpose: Identify zebrafish control and csf1r-mutant microglia transcriptomes Methods: RNA sequencing was performed on FACS-sorted control microglia (3x), csf1ra-/- microglia (3x) and csf1ra-/-;b+/- microglia (3x). 10-20 million reads per sample were obtained. Reads were mapped to zebrafish genome GRC10. Results: We identified that csf1ra-/- or csf1ra-/-;b+/- microglia transcriptomes retain most of the microglia gene expression signature but mostly show changes in chemoklines expression.
Project description:Microglia are the resident myeloid cell in the central nervous system (CNS). Like other terminally differentiated myeloid cells, microglia rely on Csf1r signaling for survival and maintenance. Surprisingly, a small subset of microglia in the murine brain can survive without Csf1r signaling, as shown in Csf1r KO mice as well as in mice that have been treated with Csf1r inhibitor PLX5622. The nature of such Csf1r independent microglial population has not been fully characterized. Here we applied single-cell RNA-seq to examine the remaining microglia in C57/BL6J mice that were treated with PLX5622 diet (1200 mg/kg, 14 days), which results >90% microglial removal.
Project description:Microglia are the resident myeloid cell in the central nervous system (CNS). Like other terminally differentiated myeloid cells, microglia rely on Csf1r signaling for survival and maintenance. Surprisingly, a small subset of microglia in the murine brain can survive without Csf1r signaling, as shown in Csf1r KO mice as well as in mice that have been treated with Csf1r inhibitor PLX5622. The nature of such Csf1r independent microglial population has not been fully characterized. Here we applied single-cell RNA-seq to examine the remaining microglia in C57/BL6J mice that were treated with PLX5622 diet (1200 mg/kg, 14 days), which results >90% microglial removal.
Project description:Microglia are long-lived myeloid cells in the central nervous system that are implicated in many neurological diseases. The differentiation of pluripotent stem cells provides an opportunity to develop in vitro human cellular models carrying disease gene mutations complementing existing animal models of disease. Microglia are particularly sensitive to their cellular environment and can adopt a variety of reactive states depending on different pathological conditions which may be difficult to mimic in vitro. Therefore, to best investigate human microglia in vivo, it would be helpful to generate mice whose endogenous microglia are exchanged with human cells without the need of genetic manipulation of donor cells which could alter microglia function. Colony stimulating factor 1 receptor (CSF1R) signaling is critical for microglial survival in mice, and humans with CSF1R mutations are born with fewer microglia. We made the surprising discovery that transplanted human pluripotent stem cell-derived microglia (hMG) survive pharmacological CSF1R inhibition unlike endogenous mouse microglia. Cellular assays confirmed that CSF1R signaling is necessary for human microglia survival and revealed differential CSF1R signaling with species-specific ligands. Moreover, receptor ligands and small molecule inhibitors acted in a competitive fashion. Based on these insights, we found that transient CSF1R inhibition after cell transplantation led to near-complete and wide-spread repopulation of hMGs into the mouse brain of immunodeficient mice with humanized CSF1 ligand. This approach allows the facile generation of mice whose brain microglia are replaced with genetically unmodified human cells.