Project description:Stress granules (SGs) assembly in response to various stress, has been demonstrated in the regulation of anti-viral immune response and tumor progression. However, lack of evidence to illustrate the relation between SGs formation and allergic diseases. Applied G3BP1-RIP-seq in RAW264.7 cells, G3BP1 binding mRNAs are defined.
Project description:Stress granules (SGs) assembly in response to various stress, has been demonstrated in the regulation of anti-viral immune response and tumor progression. However, lack of evidence to illustrate the relation between SGs formation and allergic diseases. Applying RNA-seq in primary macrophages from G3bp1f/f and G3bp1mac-/- mice, differential expressed genes were defined.
Project description:Stress granules (SGs) assembly in response to various stress, has been demonstrated in the regulation of anti-viral immune response and tumor progression. However, lack of evidence to illustrate the relation between SGs formation and allergic diseases. Using m7G meRIP-seq for CDS region of mRNA in macrophages, m7G modification of Lrp1 mRNA is defined.
Project description:Stress granules (SGs) assembly in response to various stress, has been demonstrated in the regulation of anti-viral immune response and tumor progression. However, lack of evidence to illustrate the relation between SGs formation and allergic diseases. Applying RNA-seq in total RNA and SGs of primary macrophages, SG-specific expressed genes were defined.
Project description:Inflammation is a physiopathological process triggered by infection or tissue damage. Immune system initiates coordinated sequential steps in response to these danger signals. Once the threat has been contained inflammation has to be subsequently shut down. Inflammation resolution is initiated by the reprogramming of pro-inflammatory macrophages toward a pro-resolving profile. This reprogramming is induced in particular by the non-phlogistic engulfment of apoptotic cells, mostly apoptotic neutrophils, a process called efferocytosis. As a matter of fact, macrophages are an essential linchpin regulating both inflammation triggering and sustaining and inflammation resolution. This duality can be achieved through the tremendous plasticity of these innate immune cells. Indeed, depending on microenvironmental signals (cytokines, efferocytosis, growth factors…) macrophages can adopt numerous diverse and sometimes antagonistic phenotypes. The mechanisms governing these transitions remain relatively scattered especially in human. With this project we propose to explore the mechanisms involved in human macrophage reprogramming toward a pro-resolving profile after efferocytosis. The stakes are high due to the estimated prevalence of chronic inflammatory diseases in Western society is 5 to 7%. Chronic inflammation is a burden to patient due to life-long debilitating illness and increased mortality and is also a burden to society due to high costs for therapy and care. Finding new therapies to limit chronic inflammation establishment and persistence is thus a highly valuable goal.
Project description:Efficient clearance and degradation of apoptotic cardiomyocytes by macrophages (termed efferocytosis) are critical for inflammation resolution and restoration of cardiac function after myocardial ischemia/reperfusion (I/R). Here, we define secreted and transmembrane protein 1a (Sectm1a), a cardiac macrophage-enriched gene, as a modulator of macrophage efferocytosis in I/R hearts. Upon myocardial I/R, Sectm1a-KO mice exhibit impaired macrophage efferocytosis, leading to massive accumulation of apoptotic cardiomyocytes, cardiac inflammation, fibrosis, and consequently, exaggerated cardiac dysfunction. By contrast, therapeutic administration of recombinant SECTM1A protein significantly enhances macrophage efferocytosis and improves cardiac function. Mechanistically, SECTM1A can elicit autocrine effects on the activation of glucocorticoid-induced TNF receptor (GITR) at the surface of macrophages, leading to the upregulation of liver X receptor alpha (LXRα) and its downstream efferocytosis-related genes and lysosomal enzyme genes. Our study suggests that Sectm1a-mediated activation of Gitr/LXRα axis could be a promising approach to enhance macrophage efferocytosis for the treatment of myocardial I/R injury.
Project description:We performed a FACS-based genome-wide CRISPR knockout screen in primary murine macrophages to identify regulators of efferocytosis, the phagocytic clearance of dying cells. The screen identified known and novel regulators of macrophage efferocytosis. More broadly, the screen approach can be applied to interrogate complex functional phenotypes in primary macrophages.