Project description:Peripheral serotonin (5-hydroxytryptamine, 5HT) regulates cell growth and differentiation in numerous cell types through engagement of seven types of cell surface receptors (HTR1-7). Deregulated 5HT/HTR levels contribute to pathology in chronic inflammatory diseases, with macrophages being relevant targets for the physio-pathological effects of 5HT. In fact, 5HT skews human macrophage polarization through engagement of HTR2B and HTR7 receptors. We now report that 5HT primes macrophages for reduced pro-inflammatory cytokine production and IFN type I-mediated signalling, and promotes an anti-inflammatory and pro-fibrotic gene signature in human macrophages. The acquisition of the 5HT-dependent gene profile primarily depends on the HTR7 receptor and HTR7-initiated PKA-dependent signaling. In line with the transcriptional results, 5HT upregulates TGFb1 production by human macrophages in an HTR7- and PKA-dependent manner, whereas the absence of Htr7 in vivo results in diminished macrophage infiltration and collagen deposition in a mouse model of skin fibrosis. Our results indicate that the anti-inflammatory and pro-fibrotic activity of 5HT is primarily mediated through the HTR7-PKA axis, and that HTR7 contributes to pathology in fibrotic diseases.
Project description:Peripheral serotonin (5-HT) exacerbates or limits inflammatory pathologies (pulmonary arterial hypertension, cardiac valve degeneration, systemic sclerosis, gut disorders, neuroendocrine neoplasms, arthritis) through interaction with seven types of 5-HT receptors (5-HT1-7). As central regulators of inflammation, macrophages are critical targets of 5-HT, which promotes their anti-inflammatory and pro-fibrotic polarization primarily via the 5-HT7-Protein Kinase A (PKA) axis. However, anti-inflammatory human macrophages are also characterized by the expression of 5-HT2B, an off-target of anesthetics, anti-parkinsonian drugs and Selective Serotonin Reuptake Inhibitors (SSRI) that contributes to 5-HT-mediated pathologies. Since 5-HT2B prevents mononuclear phagocyte degeneration in amyotrophic lateral sclerosis and modulates motility of murine microglial processes, we sought to determine the functional and transcriptional consequences of 5-HT2B activation in human macrophages. Ligation of 5-HT2B by the 5-HT2B-specific agonist BW723C86, which exhibits antidepressant- and anxiolytic-like effects in animal models, significantly modified the cytokine profile and the transcriptional signature in macrophages. Importantly, 5-HT2B agonist-induced transcriptional changes were partly mediated through activation of the Aryl hydrocarbon Receptor (AhR), a ligand-dependent transcription factor that regulates immune responses and the biological responses to xenobiotics. Besides, BW723C86 triggered transcriptional effects that could not be abrogated by 5-HT2B antagonists and impaired monocyte-to-osteoclast differentiation. Therefore, our results demonstrate the existence of a functional 5-HT2B-AhR link in human macrophages and indicate that the commonly used 5-HT2B agonist BW723C86 exhibits 5-HT2B-independent effects.
Project description:We isolated non-hematopoietic cells from fibrotic and non-fibrotic human bone marrow and perfomed scRNAseq on them. We identified 3 different stromal populations and 2 populations of hematopoietic progenitors. Our analysis revealed mesenchymal stromal cells (MSC) as pro-fibrotic cells. MSCs were functionally reprogrammed with loss of their progenitor status and acquisition of a pro-fibrotic phenotype in the fibrotic bone marrow. Additionally, stromal cells exhibited an upregulation of pro-inflammatory mediators like S100A8/A9.
Project description:Epoxygenases belong to the cytochrome P450 family and they generate epoxyeicosatrienoic acids (EETs) known to have anti-inflammatory effects but little is known about their role in macrophage function. By high-throughput sequencing of RNA (RNA-seq) in primary macrophages derived fromrodents and humans, we establish the relative expression of epoxygenases in these cells. Zinc-finger nuclease-mediated targeted gene deletion of the major rat macrophage epoxygenase Cyp2j4 (orthologue of human CYP2J2),resulted inreduced EET synthesis. Cyp2j4-/-macrophages have relatively increased PPARγ levels and show a pro-fibrotic transcriptome,displayingover-expression of a specific subset of genes (260 transcripts) primarily involved in extracellular matrix, with fibronectin being the most abundantly expressed transcript.Fibronectin expression is under the control of epoxygenase activity in human and rat primary macrophages. In keeping with the invitro findings, Cyp2j4-/- rats show up-regulation of type I collagen following unilateral ureter obstruction (UUO) of the kidney and quantitative proteomics analysis (LC-MS/MS) showed increased renal type I collagen and fibronectin protein abundance resulting from experimentally induced crescentic glomerulonephritis in these rats. Taken together, these results identify the rat epoxygenase Cyp2j4 as a determinant of a pro-fibrotic macrophage transcriptome that could have implications in various inflammatory conditions depending on macrophage function. Gene expression profile generated for macrophages in wild type and Cyp2j4 KO WKY rats
Project description:The RELMα+ macrophage phenotype associates with the presence of anti-inflammatory macrophages and work in other model systems has demonstrated that the balance of pro-inflammatory and anti-inflammatory macrophages is critically important in enabling the resolution of inflammation. Moreover, in the context of type 2 immunity, RELMα+ anti-inflammatory macrophages are associated with the activation of macrophages via the IL4Ra. Despite a breadth of inflammatory pathologies associated with the large intestine, including those that accompany parasitic infection, it is not known about how large intestinal macrophages are activated towards an anti-inflammatory phenotype.
Project description:We isolated non-hematopoietic cells from fibrotic and non-fibrotic mouse bone marrow and perfomed scRNAseq on them. We identified 8 different stromal populations. Our analysis revealed two distinct mesenchymal stromal cells (MSC) subsets as pro-fibrotic cells. MSCs were functionally reprogrammed in a stagedependent manner with loss of their progenitor status and initiation of differentiation in the prefibrotic stage and acquisition of a pro-fibrotic and inflammatory phenotype in the fibrotic stage. In parallel, IL-33-expressing myelinating Schwann cell progenitors expanded, likely as a repair mechanism for the previously described neuropathy in MPN.
Project description:Purpose: Investigate effects of high salt on human macrophage activation Methods: Human monocytes-derived macrophages were treated by additional 51mM NaCl for 24 hours (NaCl groups) or not (Control groups). mRNA profiles were generated by RNA-Seq, in triplicate, using Ion proton(Life tech). qRT–PCR validation was performed using SYBR Green assays. Results: High salt significantly promotes pro-inflammatory gene expressions,while suppresses the expressions of anti-inflammatory genes and pro-endocytic genes in human macrophages. Conclusions: Our results identify a novel macrophage activation state, M(Na), and high salt as a potential environmental risk factor for lung inflammation through the induction of M(Na) Human monocytes-derived macrophages were treated by additional 51mM NaCl for 24 hours (NaCl groups) or not (Control groups). mRNA profiles were generated by RNA-Seq, in triplicate, using Ion proton(Life tech). qRT–PCR validation was performed using SYBR Green assays.
Project description:The direct communication between our central nervous and inflammatory signalling systems is a well-recognised, yet poorly understood relationship. To increase our understanding of this relationship, we examined the metabolism of serotonin and its precursor tryptophan in macrophages under inflammatory settings. Both are involved in inflammatory signalling and known to play a major role in mood regulation. Tryptophan depletion by macrophages during inflammation can consequently result in a reduction of serotonin systemically and has been suggested to cause depression. Increased understanding of this system could help overcome the problem of treatment resistant depressed patients. To this end, we treated primary human monocyte derived macrophages with a range of anti-depressant/anti-inflammatory drugs and analysed their transcriptional profile under various inflammatory conditions. In addition to the classic endotoxic driver of inflammation, LPS, we also used IFNα which is a constitutive cytokine shown to directly induce depression when administered in high doses. The anti-depressant drugs were not found to have any significant effects on macrophage inflammatory signalling. However, the anti-inflammatories drugs were found to alter components of the serotonin/tryptophan metabolism pathways. This study increases our understanding of the intricacies of immune/mood cross-talk and offers into developing anti-inflammatories as co-treatment for depression. We treated human primary macrophage cells with anti-inflammatory or anti-depressant drugs and analysed their transcriptional effects during inf.lammatory signaling within the context of tryptophan metabolism/kynurenic metabolism.
Project description:Pentraxin-2 (PTX-2) is a constitutive, anti-inflammatory, innate immune plasma protein whose circulating level is decreased in chronic human fibrotic diseases. Recent studies indicate that systemic delivery of recombinant PTX-2 inhibits inflammatory diseases associated with fibrosis by blocking pro-fibrotic macrophage activation and promoting anti-inflammatory and regulatory macrophages. Here we show that recombinant human PTX-2 (rhPTX-2) retards the progression of chronic kidney disease in Col4a3 mutant mice that develop Alport syndrome, reducing blood markers of kidney failure, enhancing lifespan by 20%, and improving histological signs of disease. Exogenously-delivered rhPTX-2 is detected in macrophages but is also found in tubular epithelial cells where it counteracts macrophage activation and is cytoprotective for the epithelium. We performed transcriptional profiling of whole kidney homogenates and human proximal tubule epithelial cells (PTECs) to identify pathways differentially activated or suppressed in response to treatment with PTX-2. Computational analysis of genes regulated by rhPTX-2 identified the transcriptional regulator c-Jun and its binding partners, which form AP-1 complexes, as a central target for the function of rhPTX-2. Accordingly, PTX-2 attenuates c-Jun activation and reduces expression of AP-1 dependent inflammatory genes in both monocytes and epithelium. Our studies therefore identify rhPTX-2 as a potential therapy for chronic fibrotic disease of the kidney and an important inhibitor of pathological c-Jun signaling in this setting. 1. Total RNA from whole kidney homogenates of wildtype (Col4a3+/+) and knockout (Col4a3-/-) mice treated with PTX-2 was isolated and hybidized to Illumina Mouse WG-6 v2 Expression BeadChips. 2. Total RNA from human proximal tubules treated with plasma and PTX-2 was isolated and hybidized to Illumina HumanHT-12 v4 Expression BeadChips.
Project description:Formation of foam cell macrophages (FCMs), which sequester extracellular modified lipids, is a key event in atherosclerosis. How lipid loading affects macrophage phenotype is controversial, with evidence suggesting either pro- or anti-inflammatory consequences. To investigate this further, we compared the transcriptomes of foamy and non-foamy macrophages (NFMs) that accumulate in the subcutaneous granulomas of fed-fat ApoE null mice and normal chow fed wild-type mice in vivo. Consistent with previous studies, LXR/RXR pathway genes were significantly over-represented among the genes up-regulated in foam cell macrophages. Unexpectedly, the hepatic fibrosis pathway, associated with platelet derived growth factor and transforming growth factor-? action, was also over-represented. Several collagen polypeptides and proteoglycan core proteins as well as connective tissue growth factor and fibrosis-related FOS and JUN transcription factors were up-regulated in foam cell macrophages. Increased expression of several of these genes was confirmed at the protein level in foam cell macrophages from subcutaneous granulomas and in atherosclerotic plaques. Moreover, phosphorylation and nuclear translocation of SMAD2, which is downstream of several transforming growth factor-? family members, was also detected in foam cell macrophages. We conclude that foam cell formation in vivo leads to a pro-fibrotic macrophage phenotype, which could contribute to plaque stability, especially in early lesions that have few vascular smooth muscle cells. Samples (n=4/group): Foam cell macrophages (FCM) isolated from inflammatory sponges placed in ApoE null mice fed a high-fat diet (n=4), non-foamy macrophages (NFM) isolated from inflammatory sponges placed in control mice fed a normal diet (n=4).