MCP-1/CCR2 axis is involved in the regulation of γδT cells in lupus nephritis

γδT cells are important innate immune cells that are involved in the occurrence and development of autoimmune diseases such as systemic lupus erythematosus (SLE). Lupus nephritis (LN) is a serious complication of SLE, characterized by the accumulation of immune cells (including γδT cells) in the target organs to participate in the disease process. Therefore, clarifying how γδT cells chemotactically migrate to target organs may be a key to developing therapeutic methods against LN. Enzyme-linked immunosorbent assay (ELISA) was used to detect serum levels of chemokines in LN patients and healthy controls. Real-time polymerase chain reaction (RT-PCR) and flow cytometry were used to measure the expression of chemokine receptors on the surface of γδT cells. The chemotactic migration ability of γδT cells was detected by Transwell assay. Signalling pathway activation of γδT cells was detected by Automated Capillary Electrophoresis Immunoassay and flow cytometry. The serum levels of chemokines, including monocyte chemoattractant protein-1 (MCP-1) in LN patients, were significantly increased. CCR2, the receptor of MCP-1, was also highly expressed on the surface of peripheral γδT cells in LN patients. In addition, the exogenous addition of MCP-1 can enhance chemotactic migration of γδT cells in LN patients. MCP-1 could activate STAT3 signalling in LN patients' peripheral γδT cells. γδT cells might participate in the pathogenesis of LN through MCP-1/CCR2 axis. This finding provides new opportunities for developing treatment methods against LN by targeting MCP-1/CCR2 axis.

Propagermanium administration for patients with type 2 diabetes and nephropathy: A randomized pilot trial

AIMS

We assessed the potential efficacy and safety of propagermanium (PG), an organic compound that inhibits the C-C chemokine receptor type 2, administration in patients with type 2 diabetes and nephropathy. Furthermore, we assessed the feasibility of future studies.

MATERIALS AND METHODS

We recruited patients from nine medical institutions in Japan for this randomized, open-label, parallel two-arm pilot trial. Inclusion criteria were diagnosis of type 2 diabetes, age 30-75 years, dipstick proteinuria of ≥1+ or urinary albumin-to-creatinine ratio (UACR) of ≥30 mg/g and estimated glomerular filtration rate of ≥30 mL/min/1.73 m2. Patients were randomly assigned (1:2) using a minimization algorithm to either continuing usual care or concomitant administration of 30 mg PG per day for 12 months. The primary outcome was the change in UACR from baseline to 12 months. We also collected safety information for all patients who received at least one dose of PG.

RESULTS

We enrolled 29 patients, 10 were assigned to continue usual care and 19 to receive PG. Changes in UACR by PG in addition to the usual care were 25.0% (95% CI -20.4%, 96.5%, P = .33). No severe adverse events or renal events were observed during the study.

CONCLUSION

Although the treatment with PG was generally well tolerated, the dosage of 30 mg/d for 12 months did not reduce albuminuria when used in addition to usual care in patients with type 2 diabetes and nephropathy. Efficacy of PG should be verified in future definitive trials.

A positive feedback loop between RIP3 and JNK controls non-alcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) represents the most common liver disease in Western countries and often progresses to non-alcoholic steatohepatitis (NASH) leading ultimately to liver fibrosis and liver cancer. The occurrence of hepatocyte cell death—so far characterized as hepatocyte apoptosis—represents a fundamental step from benign steatosis toward progressive steatohepatitis. In contrast, the function of RIP3-dependent “necroptosis” in NASH and NASH-induced fibrosis is currently unknown. We show that RIP3 is upregulated in human NASH and in a dietary mouse model of steatohepatitis. RIP3 mediates liver injury, inflammation, induction of hepatic progenitor cells/activated cholangiocytes, and liver fibrosis through a pathway suppressed by Caspase-8. This function of RIP3 is mediated by a positive feedback loop involving activation of Jun-(N)-terminal Kinase (JNK). Furthermore, RIP3-dependent JNK activation promotes the release of pro-inflammatory mediators like MCP-1, thereby attracting macrophages to the injured liver and further augmenting RIP3-dependent signaling, cell death, and liver fibrosis. Thus, RIP3-dependent necroptosis controls NASH-induced liver fibrosis. This pathway might represent a novel and specific target for pharmacological strategies in patients with NASH.

Subject Categories Digestive System; Metabolism

MCP-1 downregulates MMP-9 export via vesicular redistribution to lysosomes in rat portal fibroblasts

Portal fibroblasts (PF) are one of the two primary cell types contributing to the myofibroblast population of the liver and are thus essential to the pathogenesis of liver fibrosis. Monocyte chemoattractant protein‐1 (MCP‐1) is a known profibrogenic chemokine that may be of particular importance in biliary fibrosis. We examined the effect of MCP‐1 on release of matrix metalloproteinase‐9 (MMP‐9) by rat PF. We found that MCP‐1 blocks PF release of MMP‐9 in a posttranslational fashion. We employed an optical and electron microscopic approach to determine the mechanism of this downregulation. Our data demonstrated that, in the presence of MCP‐1, MMP‐9‐containing vesicles were shunted to a lysosome‐like compartment. This is the first report of a secretory protein to be so regulated in fibrogenic cells.

Portal fibroblasts are resident liver cells that contribute to liver fibrosis. MCP‐1 induces profibrogenic changes in portal fibroblasts. Here, we found that MCP‐1 also downregulates function of the matrix metalloproteinase MMP9 via shunting of vesicles to a lysosomal compartment.

Histamine receptors expressed in circulating progenitor cells have reciprocal actions in ligation-induced arteriosclerosis

Histamine is synthesized as a low-molecular-weight amine from L-histidine by histidine decarboxylase (HDC). Recently, we demonstrated that carotid artery-ligated HDC gene-deficient mice (HDC(-/-)) showed less neointimal formation than wild-type (WT) mice, indicating that histamine participates in the process of arteriosclerosis. However, little is known about the roles of histamine-specific receptors (HHRs) in arteriosclerosis. To define the roles of HHRs in arteriosclerosis, we investigated intimal remodeling in ligated carotid arteries of HHR-deficient mice (H1R(-/-) or H2R(-/-)). Quantitative analysis showed that H1R(-/-) mice had significantly less arteriosclerogenesis, whereas H2R(-/-) mice had more, as compared with WT mice. Bone marrow transplantation from H1R(-/-) or H2R(-/-) to WT mice confirmed the above observation. Furthermore, the increased expression of monocyte chemoattractant protein (MCP-1), platelet-derived growth factor (PDGF), adhesion molecules and liver X receptor (LXR)-related inflammatory signaling factors, including Toll-like receptor (TLR3), interleukin-1 receptor (IL-1R) and tumor necrosis factor receptor (TNF-R), was consistent with the arteriosclerotic phenotype of H2R(-/-) mice. Peripheral progenitor cells in H2R(-/-) mice accelerate ligation-induced arteriosclerosis through their regulation of MCP-1, PDGF, adhesion molecules and LXR-related inflammatory signaling factors. In contrast, peripheral progenitor cells act to suppress arteriosclerosis in H1R(-/-) mice, indicating that HHRs reciprocally regulate inflammation in the ligation-induced arteriosclerosis.