Project description:We performed a single-cell transcriptome analysis of colon monocytes and macrophages in 2 control mice and 2 mice orally treated with diesel exhaust particles.
Project description:We performed a single-cell transcriptome analysis of colon monocytes and macrophages in 2 mice fed with control diet (chow) and 2 mice fed with high-fat diet for 1 week.
Project description:Mature myeloid cells play a crucial role in the pathogenesis of Crohn disease (CD) but the molecular players that regulate their functions in CD are not fully characterized. Here we show that Trim33 mRNA level is decreased in CD patient’s blood monocytes and characterize TRIM33 functions in monocytes during dextran sulfate sodium (DSS) induced colitis. Mice deleted for trim33 only in mature myeloid cells (Trim33-/- mice) display an impaired resolution of colonic inflammation. This deficiency is associated with an increased number of blood and colon neutrophils and monocytes and a decreased number of colonic macrophages. In accordance, Trim33-/- monocytes are less competent that wild type monocytes for recruitment and differentiation into macrophages at the inflammatory site. Furthermore, during resolution of DSS-induced colitis, Trim33-/- colonic macrophages display an impaired M1/M2 switch and express a low level of membrane bound TNFα known to regulate resolution of inflammation. Altogether, these results show an important role of TRIM33 in monocytes/macrophages during the resolution of DSS-induced colonic inflammation and pinpoint TRIM33 as a novel Crohn disease biomarker and as a potential therapeutic target.
Project description:The ontogeny of human lung macrophages derived from blood monocytes is poorly understood. In this study, we employed single-cell RNA-sequencing to investigate the heterogeneity of HSPC-derived human lung monocytes and macrophages in the MISTRG humanized mouse model.
Project description:Blood monocytes/macrophages infiltrate the brain after ischemic stroke and critically influence brain injury and regeneration. We investigated stroke-induced transcriptomic changes of monocytes/macrophages by RNA sequencing profiling, using a mouse model of permanent focal cerebral ischemia. Compared to non-ischemic conditions, brain ischemia induced only moderate genomic changes in blood monocytes, but triggered robust genomic reprogramming in monocytes/macrophages invading the brain. Surprisingly, functional enrichment analysis of the transcriptome of brain macrophages revealed significant overrepresentation of biological processes linked to neurovascular remodeling, such as angiogenesis and axonal regeneration, as early as 5 days after stroke, suggesting a previously underappreciated role for macrophages in initiating post-stroke brain repair. Upstream Regulator analysis predicted peroxisome proliferator-activated receptor gamma (PPARγ) as a master regulator driving the transcriptional reprogramming in post-stroke brain macrophages. Importantly, myeloid cell-specific PPARγ knockout (mKO) mice demonstrated lower post-stroke angiogenesis and neurogenesis than wild-type mice, which correlated significantly with the exacerbation of post-stroke neurological deficits in mKO mice. Collectively, our findings reveal a novel repair-enhancing transcriptome in brain macrophages during post-stroke neurovascular remodeling. As a master switch controlling genomic reprogramming, PPARγ is a rational therapeutic target for promoting and maintaining beneficial macrophage functions, facilitating neurorestoration, and improving long-term functional recovery after ischemic stroke.