Project description:Innate immune responses must be regulated in the intestine to prevent excessive inflammation. Here, using gene reporter mice, we show that a subset of mouse colonic macrophages constitutively produced the anti-inflammatory cytokine IL-10. In mice infected with Citrobacter rodentium, which is considered similar to enteropathogenic Escherichia coli infection in humans, macrophage IL-10 was required to prevent intestinal pathology and to promote survival. The synthesis of the proinflammatory cytokine IL-23 was significantly increased in infected mice with a myeloid cell specific deletion of IL-10 and the addition of IL-10 reduced in vitro IL-23 production by intestinal macrophages. Furthermore, blockade of IL-23 led to reduced morbidity and mortality in the context of macrophage IL-10 deficiency. Transcriptome analysis indicated that the reporter positive and negative colonic macrophage subsets were highly similar, but the reporter positive cells differed for the expression of CD163, an IL-10 target gene, suggesting an autocrine IL-10 signal, and when obtained from infected mice, they had reduced IL-23p19 mRNA. Interestingly, only transfer of the reporter positive cells could rescue IL-10 deficient infected mice. Therefore, these data indicate a pivotal role for a subset of intestinal macrophages that constitutively produces IL-10, perhaps acting in part in autocrine fashion, in controlling excessive innate immune activation, regulation of IL-23 production, and prevention of tissue damage after an acute bacterial infection in the intestine. Two replicates each of IL10+ and IL10- large intestinal macrophages. Data were normalized with the 'rma' function of the Bioconductor package, along with several GEO (GSM616132, GSM616136, GSM616140, GSM868296, GSM868297, GSM868298) and ArrayExpress (E-MEXP-3216: 04-M2WT, 05-M2WT, 06-M2WT) datasets.
Project description:Innate immune responses must be regulated in the intestine to prevent excessive inflammation. Here, using gene reporter mice, we show that a subset of mouse colonic macrophages constitutively produced the anti-inflammatory cytokine IL-10. In mice infected with Citrobacter rodentium, which is considered similar to enteropathogenic Escherichia coli infection in humans, macrophage IL-10 was required to prevent intestinal pathology and to promote survival. The synthesis of the proinflammatory cytokine IL-23 was significantly increased in infected mice with a myeloid cell specific deletion of IL-10 and the addition of IL-10 reduced in vitro IL-23 production by intestinal macrophages. Furthermore, blockade of IL-23 led to reduced morbidity and mortality in the context of macrophage IL-10 deficiency. Transcriptome analysis indicated that the reporter positive and negative colonic macrophage subsets were highly similar, but the reporter positive cells differed for the expression of CD163, an IL-10 target gene, suggesting an autocrine IL-10 signal, and when obtained from infected mice, they had reduced IL-23p19 mRNA. Interestingly, only transfer of the reporter positive cells could rescue IL-10 deficient infected mice. Therefore, these data indicate a pivotal role for a subset of intestinal macrophages that constitutively produces IL-10, perhaps acting in part in autocrine fashion, in controlling excessive innate immune activation, regulation of IL-23 production, and prevention of tissue damage after an acute bacterial infection in the intestine.
Project description:γδ T cells produce the primary innate source of IL-17 (γδT17) and are known to play a critical role in autoimmune and inflammatory diseases such as psoriasis. We here reported that psoriatic condition (IL-1b and IL-23) reshaped metabolic signatures and effector function of γδT17 cells compared to homeostatic condition (IL-7). Acetyl-CoA carboxylase 1 (ACC1), a rate-limiting enzyme of fatty acid synthesis (FAS), directs the fate of IL-17-producing CD4 T cells (Th17) differentiation. However, little is known about the role of ACC1-mediated FAS in their innate IL-17-producer counterpart, γδT17 cells. We further investigated the role of FAS in γδT17 by comparing the effect of pharmacological ACC inhibitor Soraphen A (SorA) on DMSO vehicle under psoriatic conditions (IL-1b and IL-23) to provide insights for clinical implication.
Project description:γδ T cells represent the primary innate source of IL-17 (γδT17) and are known to play a critical role in autoimmune and inflammatory diseases such as psoriasis. We here reported that psoriatic condition (IL-1b and IL-23) reshaped γδT17 cell metabolic signatures and promoted cytokine expression levels compared to homeostatic condition (IL-7). Acetyl-CoA carboxylase 1 (ACC1), a rate-limiting enzyme of fatty acid synthesis (FAS), directs the fate of IL-17-producing CD4 T cells (Th17) differentiation. However, little is known about the role of ACC1-mediated FAS in their innate IL-17-producer counterpart, γδT17 cells. We further investigated the role of FAS in γδT17 by comparing the effect of pharmacological inhibitor Soraphen A (SorA) on DMSO vehicle under psoriatic conditions (IL-1b and IL-23). Interestingly, ACC inhibition shifts the lipid metabolism in γδT17 cells, which allows them to cope with lipid demand without affecting cellular viability.
Project description:Understanding the mechanisms of host macrophage responses to M. tuberculosis (M.tb.) is essential for uncovering potential avenues of intervention to boost host resistance to infection. Macrophage transcriptome profiling revealed M.tb. infection strongly induced expression of several enzymes controlling tryptophan (Trp) catabolism. This included indole 2,3-dioxygenase 1 (IDO1) and tryptophan 2,3-dioxygenase (TDO2), which catalyze the rate-limiting step in the kynurenine pathway, producing ligands for the aryl hydrocarbon receptor (AHR). The AHR and heterodimeric partners AHR nuclear translocator (ARNT) and RELB are robustly expressed, and AHR and RELB levels further increased during infection. Infection enhanced AHR/ARNT and AHR/RELB DNA binding, and stimulated expression of AHR target genes, including that encoding the inflammatory cytokine IL1beta. AHR target gene expression was further enhanced by exogenous kynurenine, and exogenous Trp, kynurenine or synthetic agonist indirubin reduced mycobacterial viability. Comparative expression profiling revealed that AHR ablation diminished expression of numerous genes implicated in innate immune responses, including several cytokines. Notably, AHR depletion reduced expression of IL23A and IL12B transcripts, which encode subunits of interleukin 23 (IL23), a macrophage cytokine that stimulates production of IL22 by innate lymphoid cells. The AHR directly induced IL23A transcription in human and mouse macrophages through near-upstream enhancer regions. Taken together, these findings show that AHR signaling is strongly engaged in Mtb-infected macrophages, and has widespread effects on innate immune responses. Moreover, they reveal a cascade of AHR-driven innate immune signaling, as IL1B (IL-1β) and IL23 stimulate T cell subsets producing IL22, another direct target of AHR transactivation. Gene expression profiling of Mtb-infected THP-1 monocytic cells following siRNA-mediated Aryl hydrocarbon receptor (AHR) knockdown.
Project description:The TSC/mTOR (tuberous sclerosis complex/mammalian target of rapamycin) pathway has a central role in cell growth and is involved in human tumorigenesis. Here, we demonstrate an unexpected role of TSC2 and mTOR in regulating key inflammatory cytokines in monocytes, macrophages, and dendritic cells after bacterial stimulation. mTOR deficiency promoted IL-12/IL-23 and blocked IL-10 production via the transcription factor NF-kB. Conversely, loss of TSC2, a key negative regulator of mTOR, led to reduced NF-kB activity, limited IL-12 but enhanced IL-10 production. Transcriptional profiling demonstrated that mTOR additionally regulated many mediators important for inflammation and immunoregulation including PD-L1, CCR5, CCL22, and MCP-1. mTOR inhibition in vivo rescued susceptible mice from a lethal Listeria monocytogenes infection by modulating IL-12/IL-10 production. These data identify the TSC2/mTOR pathway as a novel pathway in innate immune responses by controlling NF-kB with profound clinical implications for infectious diseases, cancer, or transplantation. Keywords: inflammatory response of monocytes to LPS and rapamycin
Project description:Inflammatory disorders including arthritis, inflammatory bowel disease, psoriasis and multiple sclerosis are characterised by the excessive production of pro-inflammatory cytokines resulting in inflammation, tissue damage and chronic pain. In a healthy immune system, the host has developed mechanisms to protect itself from excessive inflammation. One such mechanism is mediated by the anti-inflammatory cytokine IL-10, which primarily acts to limit the production of pro-inflammatory cytokines and antigen presenting capabilities of cells in the innate immune system. Since the discovery of IL-10, much emphasis has been placed on extrapolating its exact mechanism of inhibition with the aim of potentiating its use therapeutically. Significantly, the systemic administration of IL-10 has had success in many animal models of inflammation as well as clinical success in human disorders such as psoriasis and Crohn’s disease. Despite this, major gaps in our knowledge remain which have weakened the expected therapeutic effect for this anti-inflammatory cytokine. Our early studies discovered that in response to innate immune stimulation, IL-10 can potently inhibit miR-155 (McCoy et al., 2010), a miRNA characterised as a promoter of inflammation and found over-expressed in autoimmune pathologies. This finding suggests that the IL-10/miR-155 axis is a novel mechanism utilised by IL-10 to administer its function. In this study, an Affymetrix array was employed to characterise genes regulated by the IL-10/miR-155 axis in bone-marrow derived macrophages. This project proposal aims to characterise the mechanism of IL-10 inhibition on miR-155, as well as understand the functional outcome and significance of this effect by characterising genes regulated by the IL-10/miR-155 axis.
Project description:Defense against attaching and effacing (A/E) bacteria requires the sequential generation of IL-23 and IL-22 to induce protective mucosal responses. While the critical source of IL-22 has been identified as CD4+ and Nkp46+ innate lymphoid cells (ILCs), the precise source of IL-23 is unclear. Here, we use genetic techniques to deplete specific classical dendritic cell (cDC) subsets and analyze immunity to the A/E pathogen Citrobacter rodentium. We find that Zbtb46+ cDCs, and specifically Notch2-dependent intestinal CD11b+ cDCs, but not Batf3-dependent CD103+ cDCs, are required for IL-23 production and immunity against C. rodentium. Notch2 controls cDC differentiation at a terminal step mediated by lymphotoxin signaling. Importantly, these results provide the first demonstration of a non-redundant function of CD11b+ cDCs in vivo. Analysis of genes differentially expressed between WT, Batf3 KO and Notch2 KO colons following C. rodentium infection. Mice were infected with 2 x 10^9 C. rodentium and colons harvested at either Day 4 or Day 9.
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.