Project description:Deep characterization of a large series of splenic diffuse red pulp lymphomas DNA from 5 tumor samples, corresponding to 4 cases, were analyzed with Affymetrix SNP 6.0 platform for copy number alteration study.
Project description:To compare the splenic macrophages between SIRPα-knockout mice and WT mice, we performed a complete transcript profiling of the splenic red pulp macrophages from SIRPα-KO mice compared to WT mice using mRNA microarray as a discovery platform. SIRPα-KO mice and WT mice were kept under the same condition. Macrophages were isolated from spleen red pulp of SIRPα-KO mice and WT mice. RNA was then isolated from the same number of freshly isolated macrophages.
Project description:Red pulp macrophages of the spleen mediate daily turnover of billions of senescent erythrocytes. However, the exact molecules and mechanisms involved in sequestration of senescent erythrocytes, their recognition and ultimately their turnover remain unclear and are currently subject to debate. In this study we provide evidence that the splenic environment is of substantial importance in facilitating erythrocyte turnover through induction of haemolysis. Detailed characterization of human spleen and its red pulp macrophages lead to the identification of a population of erythrocytes devoid of haemoglobin without fully disintegrating, so-called erythrocyte ghosts. By in-vivo imaging and transfusion experiments we established that senescent erythrocytes are subject to haemolysis specifically within the spleen. We show that aged erythrocytes are captured by the extracellular matrix within the red pulp of the spleen and that their retention under low shear conditions is key in driving haemolysis. In contrast to senescent erythrocytes, the erythrocyte ghost shells were found to be prone to recognition and breakdown by red pulp macrophages. As such, these data put forward haemolysis as an efficient mechanism for the turnover of senescent erythrocytes which alters our current understanding on how erythrocyte turnover is regulated.
Project description:Our understanding of the composition and functions of splenic stromal cells remains incomplete. Here, based on analysis of over 20,000 single cell transcriptomes of splenic fibroblasts, we characterized the phenotypic and functional heterogeneity of these cells in a healthy state and during virus infection. We describe eleven transcriptionally distinct fibroblastic cell clusters, reassuring known subsets and revealing yet unascertained heterogeneity amongst fibroblasts occupying diverse splenic niches. We further identify striking differences in innate immune signatures of distinct stromal compartments in vivo. Compared to other fibroblasts and to endothelial cells, Ly6C+ fibroblasts of the red pulp showed enhanced interferon-stimulated gene expression in homeostasis, upon systemic interferon stimulation and during virus infection in vivo. Collectively, we provide an updated map of fibroblastic cell diversity in the spleen that suggests a specialized innate immune function for splenic red pulp fibroblasts.
