Project description:The liver is the main gateway from the gut and the unidirectional sinusoidal flow from portal to central veins constitutes heterogenous zonation, such as peri-portal vein (PV) and peri-central vein (CV) zones; however, the functional and molecular differences among liver macrophages in these zones remain poorly understood. Here, intravital multiphoton imaging revealed significantly suppressed in PV zones. Zonation-specific single-cell transcriptome analyses detected an immuno-suppressive macrophage subset highly expressing IL-10 and Marco, a scavenger receptor, enriched in PV zones. Inhibited IL-10 signaling and Marco-deficient conditions impaired the suppressive function of these macrophages. The reduced number of Marco-positive suppressive macrophages in germ-free or antibiotic-treated conditions suggested that gut commensal bacteria were responsible for inducing this specific population. Dextran sulfate sodium-induced colitis led to inflammation in liver PV zones, which was more prominent under Marco-deficient conditions. Marco-positive inflammatory macrophages in the human liver are diminished in primary sclerosing cholangitis (PSC), an intractable disease characterized by chronic inflammation around the portal veins and bile ducts. Collectively, commensal bacteria and their pathogenic substances induce Marco-positive immunosuppressive macrophages, consequently limiting excessive inflammation in PV zones. Failure of this self-limiting system may cause hepatic inflammatory disorders, such as PSC.
Project description:The liver is the main gateway from the gut and the unidirectional sinusoidal flow from portal to central veins constitutes heterogenous zonation, such as peri-portal vein (PV) and peri-central vein (CV) zones; however, the functional and molecular differences among liver macrophages in these zones remain poorly understood. Here, intravital multiphoton imaging revealed significantly suppressed in PV zones. Zonation-specific single-cell transcriptome analyses detected an immuno-suppressive macrophage subset highly expressing IL-10 and Marco, a scavenger receptor, enriched in PV zones. Inhibited IL-10 signaling and Marco-deficient conditions impaired the suppressive function of these macrophages. The reduced number of Marco-positive suppressive macrophages in germ-free or antibiotic-treated conditions suggested that gut commensal bacteria were responsible for inducing this specific population. Dextran sulfate sodium-induced colitis led to inflammation in liver PV zones, which was more prominent under Marco-deficient conditions. Marco-positive inflammatory macrophages in the human liver are diminished in primary sclerosing cholangitis (PSC), an intractable disease characterized by chronic inflammation around the portal veins and bile ducts. Collectively, commensal bacteria and their pathogenic substances induce Marco-positive immunosuppressive macrophages, consequently limiting excessive inflammation in PV zones. Failure of this self-limiting system may cause hepatic inflammatory disorders, such as PSC.
Project description:Fibrosis is a leading cause of deaths in industrialized countries and has no effective therapy. We demonstrated that blockade of OX40L prevented inflammation-driven fibrosis affecting the skin and the lungs and promotes regression of established dermal fibrosis in different murine models. To characterize the pathways involved in the protection of skin fibrosis and affected by OX40L blocking, we used microarrays and identified distinct genes differentially expressed between ox40l+/+ and ox40l-/- in the bleomycin-induced dermal fibrosis mouse model. Total RNA were extracted from lesional skin samples of 3 ox40l+/+ and 4 ox40l-/- male mice aged 9 weeks treated with bleomycin for 3 weeks, and were hybridized on Affymetrix microarrays.
Project description:The immune system can both promote and suppress cancer. Chronic inflammation and proinflammatory cytokines such as interleukin (IL)-1 and IL-6 are considered tumor-promoting. In contrast, the exact nature of protective antitumor immunity remains obscure. In this study, we have quantified locally secreted cytokines during primary immune responses against myeloma and B-cell lymphoma in mice. Strikingly, successful cancer immunosurveillance mediated by tumor-specific CD4+ T cells was consistently associated with elevated local levels of both proinflammatory (IL-1aplha, IL-1beta, and IL-6) and T helper 1 (Th1)-associated cytokines (interferon-alpha, IL-2, IL-12). Cancer eradication was achieved by a collaboration between tumor-specific Th1 cells and tumor-infiltrating, antigen-presenting macrophages. Th1 cells induced secretion of IL-1? and IL-6 by macrophages. Th1-derived interferon-? was shown to render macrophages directly cytotoxic to cancer cells, and to induce macrophages to secrete the angiostatic chemokines CXCL9/MIG and CXCL10/IP-10. Thus, inflammation, when driven by tumor-specific Th1 cells, may prevent rather than promote cancer. Tumoricidal macrophages were isolated from Idiotype-specific TCR-transgenic SCID mice injected with MOPC315-containing Matrigel. Control macrophages were obtained from TCR-transgenic SCID mice injected with Matrigel containing antigen-loss MOPC315.