Aims/hypothesis The loss of beta cell function is a critical factor in the development of type 2 diabetes. Glucotoxicity plays a major role in the progressive deterioration of beta cell function and development of type 2 diabetes mellitus. Here we demonstrate that microRNA (miR)-30a-5p is a key player in early-stage glucotoxicity-induced beta cell dysfunction. Methods We performed northern blots, RT-PCR and western blots in glucotoxicity-exposed primary rat islets and INS-1 cells. We also measured glucose-stimulated insulin secretion and insulin content. In vivo approaches were used to evaluate the role of miR-30a-5p in beta cell dysfunction.Results miR-30a-5p expression was increased in beta cells after exposure to glucotoxic conditions, and exogenous miR-30a-5p overexpression also induced beta cell dysfunction in vitro. miR-30a-5p directly suppressed expression of Beta2/NeuroD (also known as Neurod1) by binding to a specific binding site in its 3′-untranslated region. After restoration of Beta2/NeuroD expression by knockdown miR-30a-5p or transfection of the Beta2/NeuroD gene, beta cell dysfunction, including decreased insulin content, gene expression and glucose-stimulated insulin secretion, recovered. Glucose tolerance and beta cell dysfunction improved on direct injection of Ad-si30a-5p into the pancreas of diabetic mice. Conclusions/interpretation Our data demonstrate that miR30a-5p-mediated direct suppression of Beta2/NeuroD gene expression is an important initiation step of glucotoxicityinduced beta cell dysfunction.

Purpose: Knee osteoarthritis (OA) is a debilitating disorder associated with increased physical disability. Objective physical function (e.g., performance-based measures of physical function and muscle strength) is considered clinically important as worse performance is associated with poor quality of life, a decline in physical activity levels, and mortality. Objective physical function decline is a complex multi-dimensional construct dependent on multiple factors. We aimed to 1) develop sex-specific reference values for objective physical function tests for adults with or at risk for knee OA across the spectrum of radiographic knee OA severity; and 2) determine if males and females exhibit similar functional limitations across greater radiographic knee OA severity. Methods: As part of a larger project to establish reference values and percentiles for objective physical function tests across sex, age, radiographic knee OA severity (Kellgren-Lawrence [KL] Grade), and body mass index (BMI), we included individuals in the Osteoarthritis Initiative with relevant complete data at their baseline visit (n¼3,880). Objective physical function was quantified with all available objective physical function tests within the OAI: 20-meter walk speed, 400-meter walk speed, chair stand speed, and knee extension and flexion strength. Both strength assessments were normalized to body mass. For unilateral measures we determined the most affected knee based on three criteria: 1) the knee with the worst KL grade; 2) if KL grade was equal between knees then the knee with the worst Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain score; 3) if WOMAC pain was equal between knees then the right knee was selected. We used KL grade to separate individuals into five grades of increasing radiographic knee OA severity: KL0-KL4. Sex-specific reference values were generated for each objective physical function test across each KL Grade. We used separate linear regressions to test for an interaction between sex and radiographic knee OA severity for each objective physical function test while controlling for self-reported physical activity (i.e., Physical Activity Scale for the Elderly), WOMAC knee pain, age, and BMI. Results: Participant characteristics of included and excluded individuals can be found in Table 1. Figure 1 presents the sex-specific medians for the objective physical function tests across the grades of radiographic knee OA severity. There was a significant interaction between sex and radiographic knee OA severity for 20-meter (p<0.0001) and 400-meter walk speed (p¼0.002), but not for chair stand speed (p¼0.32), knee extension strength (p¼0.94), or knee flexion strength (p¼0.63). For both walking speed assessments, females present with progressively worse walking speed with each increasing KL grade ( Figure 1A, 1B). However, walking speed in males does not appear to decline with increasing radiographic knee OA severity (Figure 1A, 1B). In females, chair stand speed demonstrates progressive differences be...

BackgroundSjögren’s syndrome (SS) is a systemic autoimmune disease that affects exocrine glands and lymphoid organs. B cell hyperactivity and imbalance between T helper 17 (Th17) cells and regulatory T (Treg) cells are involved in pathogenesis of SS. Metformin, a commonly used anti-diabetic drug, is found to have immunomodulatory effect via AMP-activated protein kinase enhanced inhibition of mTOR-STAT3 signalling.ObjectivesWe examined the therapeutic effect of metformin on SS by using animal model of SS, non-obese diabetic (NOD) mice.MethodsMetformin (50 mg/kg) or vehicle (saline) was given per oral every day from 11 weeks after birth until 20 weeks. Salivary flow rate (SFR) was addressed on every 2 or 3 weeks between 11 weeks and 20 weeks. Histologic analyses of salivary gland and spleen were performed on week 20. Expression of Inflammatory cytokine was determined by immunohistochemistry analysis and real-time PCR. Flow cytometry was performed with peripheral blood to examine Th17 and Treg cells and germinal centre (GC) B cell populations. Serum immunoglobulin level was measured by enzyme-linked immunosorbent assay. Splenic cells of NOD mice were treated with metformin or vehicle in vitro and cultured for 3 days.ResultsSFRs of metformin-treated mice recovered, whereas SFRs of those treated with vehicle declined. Histologic examination of salivary gland showed decreased infiltration of lymphocytes and reduced expression of IL-6 and TNF-alpha in metformin-treated mice. Relative expression of IL-6, TNF-alpha, and IL-17 mRNA in salivary gland and spleen also declined in metformin-treated mice. Flow cytometric analysis revealed decreased Th1 and Th17 cells and increased Treg cells in peripheral blood of mice treated with metformin. In addition, GC B cells and immunoglobulin levels were reduced in peripheral blood of mice treated with metformin. Decreased Tfh cells and increased Tfr cells were observed from in vitro cultures of splenic cells treated with metformin.ConclusionsMetformin controls B cell differentiation and keeps balance between Th17 and Treg cells in NOD mice, in addition to reducing lymphocytic infiltration and inflammatory cytokine expression in salivary gland. Metformin has potential therapeutic effects on SS.References[1] Lee SY, Moon SJ, Kim EK, Seo HB, Yang EJ, Son HJ, et al. Metformin Suppresses Systemic Autoimmunity in Roquinsan/san Mice through Inhibiting B Cell Differentiation into Plasma Cells via Regulation of AMPK/mTOR/STAT3. J Immunol2017;198–2661–70.[2] Pontarini E, Lucchesi D, Bombardieri M. Current views on the pathogenesis of Sjgren’s syndrome. Curr Opin Rheumatol2017.Disclosure of InterestNone declared