Circulating miR-320b Contributes to CD4+ T-Cell Proliferation in Systemic Lupus Erythematosus via MAP3K1.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the production of autoantibodies and tissue inflammation. Mesenchymal stem cells (MSCs) have emerged as a promising candidate therapy for SLE owing to the immunomodulatory and regenerative properties. Circulating miRNAs are small, single-stranded noncoding RNAs in a variety of body fluids that regulate numerous immunologic and inflammatory pathways. Recent studies have revealed many differentially expressed circulating miRNAs in autoimmune diseases including SLE. However, the role of circulating miRNAs in SLE has not been extensively studied. Here, we performed small RNA sequencing analysis to compare the circulating miRNA profiles of SLE patients before and after MSC transplantation (MSCT), and identified a significant decrease of circulating miR-320b level during MSCT. Importantly, we found that the expression of circulating miR-320b and its target gene MAP3K1 was closely associated with SLE disease activity. The in vitro experiments showed that decreased MAP3K1 level in SLE peripheral blood mononuclear cells (PBMCs) was involved in CD4+ T-cell proliferation. In MRL/lpr mice, miR-320b overexpression aggravated symptoms of SLE, while miR-320b inhibition could promote disease remission. Besides, MSCs regulate miR-320b/MAP3K1 expression both in vitro and in vivo. Our results suggested that circulating miR-320b and MAP3K1 may be involved in CD4+ T-cell proliferation in SLE. This trial is registered with NCT01741857.

Identifying key genes in CD4+ T cells of systemic lupus erythematosus by integrated bioinformatics analysis.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by excessive activation of T and B lymphocytes and breakdown of immune tolerance to autoantigens. Despite several mechanisms including the genetic alterations and inflammatory responses have been reported, the overall signature genes in CD4+ T cells and how they affect the pathological process of SLE remain to be elucidated. This study aimed to identify the crucial genes, potential biological processes and pathways underlying SLE pathogenesis by integrated bioinformatics. The gene expression profiles of isolated peripheral CD4+ T cells from SLE patients with different disease activity and healthy controls (GSE97263) were analyzed, and 14 co-expression modules were identified using weighted gene co-expression network analysis (WGCNA). Some of these modules showed significantly positive or negative correlations with SLE disease activity, and primarily enriched in the regulation of type I interferon and immune responses. Next, combining time course sequencing (TCseq) with differentially expressed gene (DEG) analysis, crucial genes in lupus CD4+ T cells were revealed, including some interferon signature genes (ISGs). Among these genes, we identified 4 upregulated genes (PLSCR1, IFI35, BATF2 and CLDN5) and 2 downregulated genes (GDF7 and DERL3) as newfound key genes. The elevated genes showed close relationship with the SLE disease activity. In general, our study identified 6 novel biomarkers in CD4+ T cells that might contribute to the diagnosis and treatment of SLE.

IGFBP2 function as a novel biomarker for active lupus nephritis.

In search for new targets for the diagnosis and treatment of lupus nephritis (LN), we employed TMT-liquid chromatography-triple quadrupole mass spectrometry (TMT-LC-MS/MS) combined with RNA-seq and identified a panel of proteins that was dysregulated both at protein level and mRNA level in active LN patients compared with healthy controls. We chose to study the role of IGFBP2 since it is a relatively understudied protein in the context of LN. We further validated that IGFBP2 significantly increased and correlated with SLE activity index in active LN patients. The receiver operator characteristic (ROC) curve suggested that plasma IGFBP2 had a high diagnostic efficiency for distinguishing between inactive and active LN patients (AUC = 0.992; 95% CI = 0.974-1.000; P < 0.001). We demonstrated neutralizing IGFBP2-downregulated CD4+ T cell activation, upregulated the ratio of Treg, downregulated AKT/mTOR/4E-BP1 pathway, and significantly improved nephritis in MRL/lpr mice. In all, our work demonstrated IGFBP2 as a biomarker specific for active LN and blocking IGFBP2 could be a new target for treating LN. KEY MESSAGES : Plasma IGFBP2 is a promising diagnostic marker for distinguishing stable LN from active LN, and it is also a predictor for the poor prognosis of LN. Blockade of IGFBP2 can significantly improve the pathological damage of LN. IGFBP2 may regulate activation of CD4+ T and Treg ratio. Neutralizing IGFBP2 downregulates AKT/mTOR/4E-BP1 pathway.

Mesenchymal stem cell transplantation alleviates Sjögren's syndrome symptoms by modulating Tim-3 expression.

Mesenchymal stem cell (MSC) transplantation has been proven to be an effective treatment for Sjögren's syndrome (SS) to improve salivary gland pathology and exocrine function, but the mechanism remains unclear. A recently reported inhibitory receptor, Tim-3, also appears to be closely related to autoimmune diseases. Here, we aimed to explore the roles of Tim-3 in the pathogenesis of SS and MSC treatment. The results showed that Tim-3 was downregulated in T cells of SS patients and nonobese diabetic (NOD) mice, which is correlated with SS pathogenesis. MSC transplantation ameliorated SS-like symptoms and pathological changes in the submandibular glands with modulated Tim-3 expression, resulting in attenuation of localized inflammation, fibrosis, and epithelial-mesenchymal transition. Furthermore, Tim-3 is crucial for the inhibitory effect of MSCs on PBMC proliferation in vitro. Therefore, our work has demonstrated that MSC transplantation effectively mitigates the pathological changes of SS by regulating Tim-3 expression, which provides a novel mechanism of MSC treatment and indicates a brand-new perspective of the combination of inhibitory-receptor-targeted treatment and MSC therapy in SS.

Triptolide ameliorates lupus via the induction of miR-125a-5p mediating Treg upregulation.

Triptolide is a biologically active component of the Chinese antirheumatic herbal remedy Tripterygium wilfordii Hook F, which has been shown to be effective in treating murine lupus. However, its immunological mechanisms are poorly understood. Regulatory T cells (Treg) are pivotal for maintaining peripheral self-tolerance and controlling autoimmunity. This study was undertaken to examine the therapeutic effect of triptolide in lupus mice and the related molecular mechanisms. Our results showed that triptolide treatment ameliorated serum anti-dsDNA, proteinuria and renal histopathologic assessment in MRL/lpr mice, induced the miR-125a-5p expression and enhanced the proportion of Treg in vivo. In vitro, triptolide upregulated the proportion of Treg and the miR-125a-5p expression. Down-regulation of the miR-125a-5p expression reversed the effect of triptolide on Treg. In conclusion, triptolide could induce Treg and the miR-125a-5p expression in vivo and in vitro. Inhibiting the effect of miR-125a-5p could counteract the effect of triptolide on inducing Treg. The study has strong implications for the therapeutic applications of triptolide in systemic lupus erythematosus.

miR-877-3p targets Smad7 and is associated with myofibroblast differentiation and bleomycin-induced lung fibrosis.

Myofibroblast differentiation of lung resident mesenchymal stem cells (LR-MSC) plays an important role in idiopathic pulmonary fibrosis. By comparing the expression profiles of miRNAs before and after myofibroblast differentiation of LR-MSC, we identified miR-877-3p as a fibrosis-related miRNA. We found that miR-877-3p sequestration inhibited the myofibroblast differentiation of LR-MSC and attenuates bleomycin-induced lung fibrosis by targeting Smad7. Smad7, as an inhibitory smad in the TGF-ß1 signaling pathway, was decreased in the myofibroblast differentiation of LR-MSC and up-regulation of Smad7 could inhibit the differentiation process. Our data implicates a potential application of miR-877-3p as a fibrosis suppressor for pulmonary fibrosis therapy and also as a fibrosis marker for predicting prognosis.

The toxic effects of microcystin-LR on mouse lungs and alveolar type II epithelial cells.

OBJECTIVES: Microcystin-leucine arginine (MC-LR) is produced by cyanobacteria and can accumulate in lungs through blood circulation. However, the effect of MC-LR on lung remains unclear. In this study, we investigated the chronic, low-dose effect of MC-LR on mouse lung tissues and the influence of MC-LR on mouse alveolar type II epithelial cells (ATII cells). METHODS: MC-LR was orally administered to mice at 0, 1, 10, and 40 µg/L for 6 consecutive months and mouse lungs were obtained for histopathological and immunoblot analysis. ATII cells were cultured in various concentrations of MC-LR (0, 0.5, 5, 50, 500 nmol/L) for indicated time and the cell viability and proteins change were tested. RESULTS: Our study revealed that the chronic, low-dose MC-LR exposure induced alveolar collapse and lung cell apoptosis as well as the breach of cell junction integrity. Furthermore, following treatment with MC-LR, ATII cells could uptake MC-LR, resulting in apoptosis and disruption of cell junction integrity. CONCLUSIONS: These data support the toxic potential of low-dose MC-LR in rendering chronic injury to lung tissues.

Targeted inhibition of disheveled PDZ domain via NSC668036 depresses fibrotic process.

In this study, we determined the effects of transforming growth factor-beta (TGF-ß) and Wnt/ß-catenin signaling on myofibroblast differentiation of NIH/3T3 fibroblasts in vitro and evaluated the therapeutic efficacy of NSC668036 in bleomycin-induced pulmonary fibrosis murine model. In vitro study, NSC668036, a small organic inhibitor of the PDZ domain in Dvl, suppressed ß-catenin-driven gene transcription and abolished TGF-ß1-induced migration, expression of collagen I and α-smooth muscle actin (α-SMA) in fibroblasts. In vivo study, we found that NSC668036 significantly suppressed accumulation of collagen I, α-SMA, and TGF-ß1 but increased the expression of CK19, Occludin and E-cadherin that can inhibit pulmonary fibrogenesis. Because fibrotic lung exhibit aberrant activation of Wnt/ß-catenin signaling, these data collectively suggest that inhibition of Wnt/ß-catenin signaling at the Dvl level may be an effective approach to the treatment of fibrotic lung diseases.