Project description:Sympathetic nerves have been implicated in the regulation of HSC homeostasis, we investigated whether sympathetic nerves regulated myeloid-biased differentiation of HSCs in CUMS mice. Transcriptome profiling (RNA-seq) and differential gene expression analysis of bone marrow cells were performed. In bone marrow cells of CUMS mice, the expression of arginine vasopressin receptor 2, a receptor of the stress-related neuroendocrine factor AVP, was upregulated through neuroactive ligand-receptor interaction pathway.
Project description:It has been known that the numbers of neutrophils and Ly6Chi monocytes are increased in the blood of patients with depression. To better understand how HSPCs sense and adapt disease progression in depression, we used single-cell RNA sequencing (scRNA-seq) to characterize HSPCs in bone marrow from mice models of depression induced by chronic restraint stress (CRS) and chronic unpredictable mild stress (CUMS).We found that bone marrow hematopoiesis was substantially rewired toward myeloid lineages in depression, accompanied by an increase of myeloid score in bone marrow HSPCs, suggesting myeloid biased cell production in bone marrow of depressed mice.
Project description:We found that neutrophils were homing back to bone marrow and induced myelopoiesis after AVP treatment.This study investigated how neutrophils promoted HSC differentiation by comparing the expression of genes between control and AVP treatment neutrophils.We demonstrated that AVP treatment increased the expression of a variety of cytokine genes, especially IL36G, and the augmentation of bone marrow myelopoiesis involves IL36G-IL1RL2 axis.
Project description:Background—Diabetes is a prevalent public health problem that affects about one third of the U.S. population and leads to serious vascular complications with increased risk for coronary artery disease. How bone marrow hematopoiesis contributes to diabetes complications is incompletely understood. We thus investigated the role of bone marrow endothelial cells in diabetic regulation of inflammatory myeloid cell production. Methods and Results—In three types of mouse diabetes, we observed enhanced proliferation of hematopoietic stem and progenitor cells (HSPC) leading to augmented circulating myeloid cell numbers. Analysis of bone marrow niche cells revealed that endothelial cells in diabetic mice expressed less Cxcl12, a retention factor promoting HSPC quiescence. Transcriptome-wide analysis of bone marrow endothelial cells demonstrated enrichment of genes involved in epithelial growth factor receptor (EGFR) signaling in mice with diet-induced diabetes. To explore whether endothelial EGFR plays a functional role in myelopoiesis, we generated mice with endothelial-specific deletion of EGFR (Cdh5Cre EGFRfl/fl). Unexpectedly, we found enhanced HSPC proliferation and increased myeloid cell production in Cdh5Cre EGFRfl/fl mice compared to wild type mice with diabetes. Disrupted EGFR signaling in endothelial cells decreased their expression of the HSPC retention factor angiopoietin-1. We tested the functional relevance of these findings for wound healing and atherosclerosis, both implicated in complications of diabetes. Inflammatory myeloid cells accumulated more in skin wounds of diabetic Cdh5Cre EGFRfl/fl mice, significantly delaying wound closure. Atherosclerosis accelerated in Cdh5Cre EGFRfl/fl mice, leading to larger and more inflamed atherosclerotic lesions in the aorta. Conclusions—In diabetes, bone marrow endothelial cells participate in the dysregulation of bone marrow hematopoiesis and promote cardiovascular complications via leukocyte overproduction. Specifically, diabetes reduces endothelial production of Cxcl12, a quiescence-promoting niche factor that reduces stem cell proliferation. We also describe a previously unknown counter-regulatory pathway, in which protective endothelial EGFR signaling curbs HSPC proliferation and myeloid cell production via angiopoietin-1.
Project description:Infection is able to elicit innate immunological memory by enhancing a long-term myeloid output even after the inciting infectious agent has been cleared. However, mechanisms underlying such a regulation are not fully understood. Using a mouse polymicrobial peritonitis (sepsis) model, we show that severe infection leads to increased, sustained myelopoiesis after the infection is resolved. The infection experience is imprinted in the bone marrow (BM) stromal cells, in the form of a constitutive upregulation of the tissue inhibitor of metalloproteinases 1 (TIMP1). TIMP1 antagonizes the function of ADAM10, an essential cleavage enzyme for the activation of Notch which in turn suppresses myelopoiesis. While TIMP1 is dispensable for myelopoiesis under the steady state, increased TIMP1 enhances myelopoiesis post infection. Thus, our data reveal that infection could establish an inflammatory memory in the BM niche to support a long-term enhanced output of innate immune cells.