Project description:Interleukin 23 (IL-23) is integral to the pathogenesis of chronic inflammation. The resolution of acute inflammation is an active process mediated by specific signals and mediators such as resolvin E1 (RvE1). Here we provide evidence that RvE1, in nanogram quantities, promoted the resolution of inflammatory airway responses in part by directly suppressing the production of IL-23 and IL-6 in the lung. Also contributing to the pro-resolution effects of RvE1 treatment were higher concentrations of interferon-gamma in the lungs of RvE1-treated mice. Our findings indicate a pivotal function for IL-23 and IL-6, which promote the survival and differentiation of IL-17-producing T helper cells, in maintaining inflammation and also identify an RvE1-initiated resolution program for allergic airway responses.
Project description:The potential of omega-3 poly-unsaturated fatty acids (PUFAs) as a therapeutic target for psoriasis, a chronic inflammatory skin disease of IL-23/IL-17 axis, is a long-disputed question, since various epidemiological studies have suggested the association between high-intake of omega-3 PUFAs and the reduced frequency and severity of psoriasis. However, their actual significance and the molecular mechanisms remain largely unknown. To address these issues, we focused on resolvin E1 (RvE1), an omega-3 PUFAs-derived metabolite, and examined its effects on psoriatic dermatitis, using an imiquimod-induced mouse psoriasis model. RvE1 potently suppressed the inflammatory cell infiltration and epidermal hyperplasia in the psoriatic skin. RvE1 decreased the mRNA expression of IL-23 in the skin. Consistently, RvE1 inhibited IL-23 production by dendritic cells (DCs) in vitro. Furthermore, RvE1 exerted inhibitory effects on migration of cutaneous DCs and γδ T cells, a major IL-17-producing cell population in mouse, both in vivo and in vitro. These suppressive effects of RvE1 were mediated by its antagonistic function on BLT1, a receptor of leukotriene B4, and were also observed in human DCs, Th17 and Tc17 cells. Our results indicate a novel mechanism of omega-3 PUFA-mediated amelioration of psoriasis, and suggest a potential of RvE1 as a therapeutic target for psoriasis.
Project description:Periodontitis is a biofilm-induced inflammatory disease characterized by dysbiosis of the commensal periodontal microbiota. It is unclear how natural regulation of inflammation affects the periodontal biofilm. Promoters of active resolution of inflammation, including resolvin E1 (RvE1), effectively treat inflammatory periodontitis in animal models. The goals of this study were 1) to compare periodontal tissue gene expression in different clinical conditions, 2) to determine the impact of local inflammation on the composition of subgingival bacteria, and 3) to understand how inflammation impacts these changes. Two clinically relevant experiments were performed in rats: prevention and treatment of ligature-induced periodontitis with RvE1 topical treatment. The gingival transcriptome was evaluated by RNA sequencing of mRNA. The composition of the subgingival microbiota was characterized by 16S rDNA sequencing. Periodontitis was assessed by bone morphometric measurements and histomorphometry of block sections. H&E and tartrate-resistant acid phosphatase staining were used to characterize and quantify inflammatory changes. RvE1 treatment prevented bone loss in ligature-induced periodontitis. Osteoclast density and inflammatory cell infiltration in the RvE1 groups were lower than those in the placebo group. RvE1 treatment reduced expression of inflammation-related genes, returning the expression profile to one more similar to health. Treatment of established periodontitis with RvE1 reversed bone loss, reversed inflammatory gene expression, and reduced osteoclast density. Assessment of the rat subgingival microbiota after RvE1 treatment revealed marked changes in both prevention and treatment experiments. The data suggest that modulation of local inflammation has a major role in shaping the composition of the subgingival microbiota.
Project description:ObjectivesTo determine whether the combination of resolvin E1 (RvE1) and lipoxin A4 (LXA4) could promote resolution of pulpitis and to investigate the mechanism.Materials and methodsPreliminary screening was first conducted in four specialized pro-resolving mediators (SPMs). Real-time quantitative polymerase chain reaction, western blotting, enzyme-linked immunosorbent assay and double-immunofluorescence labelling were employed to assess the expression of RelA, SIRT1, SIRT6, SIRT7 and pro-inflammatory factors. Dental pulp fibroblasts (DPFs) were transfected with siRNA to assess the biological role of SIRT7. A pulpitis model was utilized to evaluate the in vivo curative effect.ResultsPreliminary results showed that RvE1 and LXA4 reduced the expression of RelA more markedly than other two SPMs. Both RvE1 and LXA4 treatment downregulated nuclear factor kappa B (NF-κB) activation and increased the expression of SIRT1, SIRT6 and SIRT7, more so in combination than alone. Double-immunofluorescence labelling showed that SIRT7 co-localized with p-p65 and Ac-p65 in the nucleus. Inhibiting ChemR23 and ALX reversed the expression of RelA mRNA, p-p65 and Ac-p65 proteins, pro-inflammatory factors, SIRT1, SIRT6 and SIRT7. Silencing SIRT7 significantly increased p-p65 and Ac-p65 protein levels and decreased SIRT1 and SIRT6 expression. In vivo experiments showed that combined administration of RvE1 and LXA4 promoted pulpitis markedly to resolution.ConclusionsCombination of RvE1 and LXA4 effectively inhibited NF-κB activation by upregulating SIRT7 expression in DPFs, leading to reduced production of pro-inflammatory factors and promotion of pulpitis resolution.
Project description:Resolvins are endogenous lipid mediators that actively regulate the resolution of acute inflammation. Resolvin E1 (RvE1; (5S,12R,18R)-trihydroxy-6Z,8E,10E,14Z,16E-eicosapentaenoic acid) is an endogenous anti-inflammatory and pro-resolving mediator derived from eicosapentaenoic acid that regulates leukocyte migration and enhances macrophage phagocytosis of apoptotic neutrophils to resolve inflammation. In the inflammatory milieu, RvE1 mediates counter-regulatory actions initiated via specific G protein-coupled receptors. Here, we have identified RvE1-specific signaling pathways initiated by the RvE1 receptor ChemR23. RvE1 stimulated phosphorylation of Akt that was both ligand- and receptor-dependent. RvE1 regulated Akt phosphorylation in a time (0-15 min)- and dose-dependent (0.01-100 nm) manner in human ChemR23-transfected Chinese hamster ovary cells. RvE1 stimulated phosphorylation of both Akt and a 30-kDa protein, a downstream target of Akt, identified using a phospho-Akt substrate antibody. The 30-kDa protein was identified as ribosomal protein S6, a translational regulator, and its phosphorylation was inhibited by a phosphatidylinositol 3-kinase (PI3K) inhibitor (wortmannin) and an ERK inhibitor (PD98059) but not by a p38-MAPK inhibitor (SB203580). Ribosomal protein S6 is a downstream target of the PI3K/Akt signaling pathway as well as the Raf/ERK pathway. In ChemR23-expressing differentiated HL60 cells, RvE1 also stimulated the phosphorylation of ribosomal protein S6. In addition, RvE1 enhanced phagocytosis of zymosan A by human macrophages, which are inhibited by PD98059 and rapamycin (mTOR inhibitor). These results indicate that RvE1 initiates direct activation of ChemR23 and signals receptor-dependent phosphorylation. These phosphorylation-signaling pathways identified for RvE1 receptor-ligand interactions underscore the importance of endogenous pro-resolving agonists in resolving acute inflammation.
Project description:Inflammation in arterial walls leads to coronary artery disease (CAD). We previously reported that a high omega-3 fatty index was associated with prevention of progression of coronary atherosclerosis, a disease of chronic inflammation in the arterial wall. However, the mechanism of such benefit is unclear. The two main omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are precursors of specialized pro-resolving lipid mediators (SPMs)-resolvins and maresins-which actively resolve chronic inflammation. To explore whether SPMs are associated with coronary plaque progression, levels of SPMs and proinflammatory mediators (leukotriene B4 [LTB4 ] and prostaglandins) were measured using liquid chromatography-tandem mass spectrometry in 31 statin-treated patients with stable CAD randomized to either EPA and DHA, 3.36 g daily, or no EPA/DHA (control). Coronary plaque volume was measured by coronary computed tomographic angiography at baseline and at 30-month follow-up. Higher plasma levels of EPA+DHA were associated with significantly increased levels of two SPMs-resolvin E1 and maresin 1-and 18-hydroxy-eicosapentaenoic acid (HEPE), the precursor of resolvin E1. Those with low plasma EPA+DHA levels had a low (18-HEPE+resolvin E1)/LTB4 ratio and significant plaque progression. Those with high plasma EPA+DHA levels had either low (18-HEPE+resolvin E1)/LTB4 ratios with significant plaque progression or high (18-HEPE+resolvin E1)/LTB4 ratios with significant plaque regression. These findings suggest that an imbalance between pro-resolving and proinflammatory lipid mediators is associated with plaque progression and potentially mediates the beneficial effects of EPA and DHA in CAD patients.
Project description:Resolvin E1 (RvE1) is a specialized pro-resolving lipid mediator derived from eicosapentaenoic acid and plays a critical role in resolving inflammation and tissue homeostasis. Th17 cells are a distinct group of T helper (Th) cells with tissue-destructive functions in autoimmune and chronic inflammatory diseases via the secretion of IL-17. Dendritic cell (DC)-mediated antigen presentation regulates the Th17-induced progression of inflammation and tissue destruction. In this study, we hypothesized that the RvE1 would restore homeostatic balance and inflammation by targeting the Th17 function. We designed three experiments to investigate the impact of RvE1 on different phases of Th17 response and the potential role of DCs: First CD4+ T cells were induced by IL-6/TGFβ to measure the effect of RvE1 on Th17 differentiation in an inflammatory milieu. Second, we measured the impact of RvE1 on DC-stimulated Th17 differentiation in a co-culture model. Third, we measured the effect of RvE1 on DC maturation. RvE1 blocked the CD25, CCR6 and IL-17 expression; IL-17, IL-21, IL-10, and IL-2 production, suggesting inhibition of T cell activation, Th17 stimulation and chemoattraction. RvE1 also suppressed the activation of DCs by limiting their pro-inflammatory cytokine production. Our findings collectively demonstrated that the RvE1 targeted the Th17 activation and the DC function as a potential mechanism for inflammatory resolution and acquired immune response.
Project description:Resolution of acute inflammation is an active process essential for appropriate host responses, tissue protection and the return to homeostasis. During resolution, specific omega-3 polyunsaturated fatty-acid-derived mediators are generated within resolving exudates, including resolvin E1 (RvE1) and protectin D1 (PD1). It is thus important to pinpoint specific actions of RvE1 and PD1 in regulating tissue resolution. Here we report that RvE1 and PD1 in nanogram quantities promote phagocyte removal during acute inflammation by regulating leukocyte infiltration, increasing macrophage ingestion of apoptotic polymorphonuclear neutrophils in vivo and in vitro, and enhancing the appearance of phagocytes carrying engulfed zymosan in lymph nodes and spleen. In this tissue terrain, inhibition of either cyclooxygenase or lipoxygenases--pivotal enzymes in the temporal generation of both pro-inflammatory and pro-resolving mediators--caused a 'resolution deficit' that was rescued by RvE1, PD1 or aspirin-triggered lipoxin A4 analogue. Also, new resolution routes were identified that involve phagocytes traversing perinodal adipose tissues and non-apoptotic polymorphonuclear neutrophils carrying engulfed zymosan to lymph nodes. Together, these results identify new active components for postexudate resolution traffic, and demonstrate that RvE1 and PD1 are potent agonists for resolution of inflamed tissues.
Project description:Specialized proresolving mediators (SPMs) decrease NF-κB activity to prevent excessive tissue damage and promote the resolution of acute inflammation. Mechanisms for NF-κB regulation by SPMs remain to be determined. In this study, after LPS challenge, the SPMs 15-epi-lipoxin A4 (15-epi-LXA4), resolvin D1, resolvin D2, resolvin D3, and 17-epi-resolvin D1 were produced in vivo in murine lungs. In LPS-activated human bronchial epithelial cells, select SPMs increased expression of the NF-κB regulators A20 and single Ig IL-1R-related molecule (SIGIRR). Of interest, 15-epi-LXA4 induced A20 and SIGIRR in an lipoxin A4 receptor/formyl peptide receptor 2 (ALX/FPR2) receptor-dependent manner in epithelial cells and in murine pneumonia. This SPM regulated NF-κB-induced cytokines to decrease pathogen-mediated inflammation. In addition to dampening lung inflammation, surprisingly, 15-epi-LXA4 also enhanced pathogen clearance with increased antimicrobial peptide expression. Taken together, to our knowledge these results are the first to identify endogenous agonists for A20 and SIGIRR expression to regulate NF-κB activity and to establish mechanisms for NF-κB regulation by SPMs for pneumonia resolution.