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:RNA transcriptome difference between WT and SIRPa knockout (KO) bone marrow derived macrophages (BMDMs). To understand how SIRPa inhibits the phagocytotic capacity of macrophages, a mouse lacking SIRPa was generated, and the transcriptional profiles of BMDMs from wild-type and SIRPa KO mice were compared, using RNA sequencing.
Project description:Resident macrophages are important for maintaining tissue homeostasis and for defence against infections, but their precise functions in different tissues are not fully elucidated.We have used high resolution quantitative proteomics to investigate the functions of splenic red pulp macrophages and peritoneal cavity macrophages in the steady-state. The validation of several proteins at cellular expression levels by the flow cytometry analysis was consistently in agreement with the proteomics data. Peritoneal macrophages were shown to be enriched in a number of key enzymes and metabolic pathways normally associated with the liver, such as metabolism of fructose, detoxification, nitrogen homeostasis and the urea cycle. Supporting observations in proteomics, we find that PM are able to utilise glutamine and glutamate which are rich in peritoneum for urea generation. In comparison, splenic red pulp macrophages were enriched in proteins important for adaptive immunity such as antigen presenting MHC molecules, in addition to proteins required for erythrocyte homeostasis and iron turnover. We also show that these tissue macrophages may utilise carbon and nitrogen substrates for different metabolic fates to support distinct tissue-specific roles. This study provides a valuable resource for biologists interested in the functions of tissue macrophages.
Project description:Acute malaria infection with P. chabaudi obliterates embryonically seeded tissue-resident red pulp macrophages in the spleen of C57Bl/6J mice - regardless of whether the infection is mild (mosquito transmitted P. chabaudi AS - no hyperparasitaemia, no measurable clinical manifestations of disease other than low-grade anaemia) or severe (mosquito transmitted P. chabaudi AJ - acute hyperparasitaemia, severe anaemia, hypothermia and prostration). Red pulp macrophages return 100 days later, once mice cleared parasitaemia. We then flow sorted 10,000 red pulp macrophages (lineage-, autofluorescent, F4/80+, B220-, CD11bint, CD11cint) directly into Trizol, extracted total RNA and analysed their transciptome using the affymetrix mouse exon 1.0 ST array. Red pulp macrophages from mice once infected with mild AS or severe AJ P. chabaudi parasites were compared to uninfected age-matched mice. We uncover that red pulp macrophages isolated from the spleens of once-malaria infected mice are transcriptionally identical to prenatally seeded red pulp macrophages from uninfected mice. The spleen tissue niche thus imprints an identical functional profile onto these cells - regardless of their origin.
Project description:Both iron homeostasis and erythropoiesis are known to be affected by aging. Iron needs in mammals are met primarily by iron recycling from senescent red blood cells (RBCs), a task chiefly accomplished by red pulp macrophages (RPMs) in the spleen. Given that RPMs continuously process iron, their cellular functions might be susceptible to age-dependent decline, a possibility that has been unexplored to date. In our project, we identified a formation of undegradable iron- and heme-rich extracellular aggregates in the spleens of 10-11-month-old female mice. To better understand the origin of these aggregates, here, we performed: i) protein identification and intrasample quantification (iBAQ) of proteins of magnetically-isolated red pulp macrophages from spleens of two female 8-weeks-old C57BL/6J (maintained on a standard diet) and ii) label-free quantification of proteins of the splenic protein aggregates formed in the mouse spleen 24 hours after intraperitoneal iron dextran injection, using dextran-injected mice as a control. Two 8-week-old C57BL/6J mice per group were analyzed. This dataset is related to the project PXD032900, which describes quanytitative analysis of proteins in aggregates magnetically isolated from spleen of aged (standard or iron-reduced diet) and young mice (standard diet).
Project description:Macrophages are central in regulating iron homeostasis. Transcription repressor Bach2 regulates by heme. Here we investigated the relationship between heme-regulated Bach2 and macrophage in spleen. We found that gene expression were not many change between WT and Bach2 knock out mice in red-pulp macrophage.Our results suggest that the function of the red-pulp macrophage is not dependent on according to expression of Bach2.
Project description:Macrophages in the bone marrow erythroblastic island (EIM) and splenic red pulp (RPM) are required for terminal erythropoiesis and removal of aged erythrocytes, respectively. This manuscript shows that EIM and RPM development require both PPARg and Spi-C.
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:The goal of this experiment was to use global gene expression profiling to assess the global genetic reprogramming of different types of splenic mononuclear phagocytes early after MCMV infection in vivo. This study includes new samples (GSM3178486-GSM3178497; available below) profiling splenic CD11b+ conventional dendritic cells (cDC2), classical monocytes (cMo) and red pulp macrophages (RPM) from untreated or day 1.5 MCMV-infected mice together with re-analysis of previously published data in order to examine the similarities in the pDC gene expression profiles across datasets. The complete processed data for all analyzed samples, with and without batch correction, are available at the foot of this series. Included is a text file with a list of all re-analyzed samples and data processing protocols for the re-analysis.