Inflammation In Muscle Tissue Research Articles

Antioxidant anthocyanin synergistic immune enhancer nanopeptide C-I20 remarkably enhances the protective effect of largemouth bass against largemouth bass ranavirus

Largemouth bass ranavirus (LMBV) infection results in huge economic losses in largemouth bass (Micropterus salmoides) industry. Nanopeptide C-I20 and anthocyanins have a positive effect on promoting immune responses and antioxidant mechanisms in several aquatic organisms, and are therefore used to inhibit LMBV infection. In this study, we developed an LMBV immersion challenge model using three different viral concentrations (1 × 104 copies/mL, 1 × 105 copies/mL, and 1 × 106 copies/mL) to infect largemouth bass, and LMBV-MCP mRNA expression was detected in infected fish. Following infection, the fish exhibited severe external ulceration, redness swelling, and darkening of the skin. Histopathological examination revealed significant necrosis and inflammation in muscle tissue, epithelial cell shedding in renal tubules, macrophage aggregation centers and cellular vacuolization in spleen and head kidney, and cellular hypertrophy in liver. To mitigate LMBV infection, we explored the protective effects of a combined treatment strategy involving C-I20 and anthocyanin. Overall, the combination of anthocyanin and C-I20 demonstrated the highest protective efficacy, significantly reducing viral loads in muscle, liver, spleen, and head kidney. Moreover, this treatment regimen enhanced antioxidant enzyme activities (T-AOC, TSOD, GSH-Px, CAT) and modulated important immune genes (IL-1, IL-8, TNF-α, IL-10, Mx, and IgM) expression. In conclusion, the synergistic application of anthocyanin and C-I20 demonstrates significant efficacy in mitigating LMBV infection. This research introduces a novel and promising approach to managing infectious diseases in aquaculture settings.

ADAR2 deficiency ameliorates non-alcoholic fatty liver disease and muscle atrophy through modulating serum amyloid A1.

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide. Sarcopenia is a syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength, which is commonly associated with NAFLD. Adenosine-to-inosine editing, catalysed by adenosine deaminase acting on RNA (ADAR), is an important post-transcriptional modification of genome-encoded RNA transcripts. Three ADAR gene family members, including ADAR1, ADAR2 and ADAR3, have been identified. However, the functional role of ADAR2 in obesity-associated NAFLD and sarcopenia remains unclear. ADAR2+/+/GluR-BR/R mice (wild type [WT]) and ADAR2-/-/GluR-BR/R mice (ADAR2 knockout [KO]) were subjected to feeding with standard chow or high-fat diet (HFD) for 20weeks at the age of 5weeks. The metabolic parameters, hepatic lipid droplet, grip strength test, rotarod test, muscle weight, fibre cross-sectional area (CSA), fibre types and protein associated with protein degradation were examined. Systemic and local tissues serum amyloid A1 (SAA1) were measured. The effects of SAA1 on C2C12 myotube atrophy were investigated. ADAR2 KO mice fed with HFD exhibited lower body weight (-7.7%, P<0.05), lower liver tissue weight (-20%, P<0.05), reduced liver lipid droplets in concert with a decrease in hepatic triglyceride content (-24%, P<0.001) and liver injury (P<0.01). ADAR2 KO mice displayed protection against HFD-induced glucose intolerance, insulin resistance and dyslipidaemia. Skeletal muscle mass (P<0.01), muscle strength (P<0.05), muscle endurance (P<0.001) and fibre size (CSA; P<0.0001) were improved in ADAR2 KO mice fed with HFD compared with WT mice fed with HFD. Muscle atrophy-associated transcripts, such as forkhead box protein O1, muscle atrophy F-box/atrogin-1 and muscle RING finger 1/tripartite motif-containing 63, were decreased in ADAR2 KO mice fed with HFD compared with WT mice fed with HFD. ADAR2 deficiency attenuates HFD-induced local liver and skeletal muscle tissue inflammation. ADAR2 deficiency abolished HFD-induced systemic (P<0.01), hepatic (P<0.0001) and muscular (P<0.001) SAA1 levels. C2C12 myotubes treated with recombinant SAA1 displayed a decrease in myotube length (-37%, P<0.001), diameter (-20%, P<0.01), number (-39%, P<0.001) and fusion index (-46%, P<0.01). Myogenic markers (myosin heavy chain and myogenin) were decreased in SAA1-treated myoblast C2C12 cells. These results provide novel evidence that ADAR2 deficiency may be important in obesity-associated sarcopenia and NAFLD. Increased SAA1 might be involved as a regulatory factor in developing sarcopenia in NAFLD.

A Complex Pattern of Gene Expression in Tissue Affected by Viperid Snake Envenoming: The Emerging Role of Autophagy-Related Genes.

Viperid snake venoms induce severe tissue damage, characterized by the direct toxic action of venom components, i.e., phospholipases A2 (PLA2s) and metalloproteinases (SVMPs), concomitantly with the onset of endogenous inflammatory processes, in an intricate scenario of tissue alterations. Understanding the expression of relevant genes in muscle tissue will provide valuable insights into the undergoing pathological and inflammatory processes. In this study, we have used the Nanostring technology to evaluate the patterns of gene expression in mouse skeletal muscle 1 h, 6 h, and 24 h after injection of the venoms of Bothrops asper and Daboia russelii, two medically relevant species in Latin America and Asia, respectively, with somewhat different clinical manifestations. The dose of venoms injected (30 µg) induced local pathological effects and inflammation in muscle tissue. We focused our analysis on genes related to extracellular matrix (ECM) metabolism, immune system, programmed cell death, and autophagy. The results revealed a complex pattern of expression of genes. Regarding ECM metabolism and regulation, up-regulated genes included proteinase inhibitor Serpine 1, thrombospondin 1, collagens 1A1 and 4A1 (at 1 h in the case of B. asper), TIMP1, MMP-3 (at 24 h), and lysil oxidase (LOX). In contrast, collagen chains 5A3 and 5A1 were down-regulated, especially at 6 h. Transforming growth factor β (TGF-β) and several genes related to myofibroblast regulation were also up-regulated, which might be related to the development of fibrosis. Several genes related to cytokine and chemokine synthesis and regulation and NFκB signaling were also up-regulated. Our observations show a variable expression of genes associated with programmed cell death and autophagy, thus revealing a hitherto unknown role of autophagy in tissue affected by snake venoms. These results provide clues to understanding the complex pattern of gene expression in tissue affected by viperid snake venoms, which likely impacts the final pathophysiology of damaged tissue in envenomings.

Osthole ameliorates myonecrosis caused by Clostridium perfringens type A infection in mice

This study aimed to investigate the protective effect of the nature product osthole (OST) against Clostridium perfringens type A infection-caused myonecrosis in a mouse model. Male mice were divided into (1) control, (2) infected, (3) OST50 and (4) OST100 treatment groups. In the infected groups, mice were intramuscularly injected with 1 × 108 CFU of C. perfringens per day for 6 days. Mice in the OST50 and OST100 groups were administrated intraperitoneally with OST at the doses of 50 or 100 mg/kg per day post C. perfringens infection. Our results showed that C. perfringens infection caused marked necrosis and inflammatory cell infiltration in the muscle tissues of mice. Mice in the OST50 and OST100 treatment groups displayed significantly attenuated C. perfringens infection-induced lipid peroxidation, oxidative stress, and apoptosis in their muscle tissue. Furthermore, OST treatment significantly downregulated the expressions of NF-κB, IL-1β, and TNF-α mRNA and protein levels, while concomitantly upregulating the expressions of Nrf2 and HO-1 mRNA and protein. OST treatments also inhibited the expression of phosphorylation (p)-p38, p-mTOR, and p-Erk1/2 proteins, and upregulated LC3II and Beclin1 proteins. In summary, our results reveal that OST therapy confers a protective effect against C. perfringens infection-induced oxidative stress and inflammation in muscle tissue, via activation of Nrf2/HO-1 and autophagy pathways and inhibition of p38, Erk1/2 and NF-κB pathways.

Water-soluble pristine C60 fullerenes attenuate isometric muscle force reduction in a rat acute inflammatory pain model

BackgroundBeing a scavenger of free radicals, C60 fullerenes can influence on the physiological processes in skeletal muscles, however, the effect of such carbon nanoparticles on muscle contractility under acute muscle inflammation remains unclear. Thus, the aim of the study was to reveal the effect of the C60 fullerene aqueous solution (C60FAS) on the muscle contractile properties under acute inflammatory pain.MethodsTo induce inflammation a 2.5% formalin solution was injected into the rat triceps surae (TS) muscle. High-frequency electrical stimulation has been used to induce tetanic muscle contraction. A linear motor under servo-control with embedded semi-conductor strain gauge resistors was used to measure the muscle tension.ResultsIn response to formalin administration, the strength of TS muscle contractions in untreated animals was recorded at 23% of control values, whereas the muscle tension in the C60FAS-treated rats reached 48%. Thus, the treated muscle could generate 2-fold more muscle strength than the muscle in untreated rats.ConclusionsThe attenuation of muscle contraction force reduction caused by preliminary injection of C60FAS is presumably associated with a decrease in the concentration of free radicals in the inflamed muscle tissue, which leads to a decrease in the intensity of nociceptive information transmission from the inflamed muscle to the CNS and thereby promotes the improvement of the functional state of the skeletal muscle.

Identifying molecular targets for rational immunosuppressive strategies in patients with immune checkpoint therapy-induced myocarditis and myositis.

2511 Background: Immune checkpoint therapies (ICTs) can induce durable anti-tumor responses but also life-threatening immune-related adverse events (irAEs). Myocarditis, myositis, and myasthenia gravis (MG) are rare, often concurrent irAEs with mortality up to 40%. Steroids are the standard first-line treatment and have significant adverse events with prolonged use. We and others have identified serum autoantibodies in these irAEs, suggestive of B cell contribution to pathogenesis. Furthermore, although prior studies have shown T cells and myeloid cells in inflamed muscle tissue, their specific subtype and role in disease pathogenesis have yet to be defined. This understanding may contribute to the development of more effective immunosuppressive strategies. Hypothesis: In addition to T cells, plasma B and myeloid cells contribute to the pathogenesis of ICT-induced myocarditis, myositis, and MG. Methods: We enrolled patients with suspected ICT-induced myocarditis, myositis, and MG on an IRB-approved laboratory protocol. Diagnosis required: 1) symptoms requiring hospitalization; 2) elevated serum markers (creatine kinase ≥5x normal, troponin &gt;99th percentile or detection of autoantibodies for MG); and 3) positive biopsy, electromyography, or cardiac MRI. Patients underwent standard diagnostic testing (including endomyocardial and/or skeletal muscle biopsy) and treatment as clinically indicated. Results: 23 patients were enrolled (n=13, confirmed irAE; n=10, negative control). Most patients received combination ICT (10/13, 77%). Anti-striated muscle and/or acetylcholine receptor binding antibodies were detected in 7/13 patients (54%), including 3 without MG (known to have both T and B cell etiologies). Single cell RNA sequencing of patient tissue (confirmed irAEs: cardiac n=10, skeletal n=9; control: cardiac n=4, skeletal n=5) identified specific populations of myeloid and CD8+ T cells conserved between inflamed cardiac and skeletal muscle. Conclusions: Specific populations of T cells, myeloid cells, and plasma B cells are potential targets for rational immunosuppressive strategies in ICT-induced myocarditis and myositis and will be tested in murine models to inform future clinical trial design. [Table: see text]

A Short Review on Blackleg in Ruminants

Blackleg is an endogenous acute infection that principally affects ruminants. It is Clostridium chauvoei, anaerobic spore-forming bacteria, causes the disease, which manifests as an acute, localized inflammation of muscle tissue produced by development of the blackleg organisms. Although blackleg may occur at any time of year, more cattle are lost during the summer months. In recent years, the major virulence factors of C. chauvoei have been discovered and described. However, the pathogenesis of blackleg in ruminant, and in particular the pathogen’s movement from the place of entrance to the affected tissues is yet unknown. When outbreaks arise, it is prevented by vaccination; in the early stages of the disease, it is treated with antibiotics, most notably penicillin, which is an effective therapy for the condition. Control of this disease is based on strict husbandry methods and a vaccination program. The key virulence factors of C. chauvoei have been found and characterized in recent years. This review covers the most recent research discoveries that contribute to a better understanding of the disease and provides the basis for preventative efforts.

Jellyfish Nemopilema nomurai causes myotoxicity through the metalloprotease component of venom

Jellyfish envenomation is a common medical problem in many countries. However, the myotoxicity and effector molecules of scyphozoan venoms remain uninvestigated. Here, we present the myotoxicity of nematocyst venom from Nemopilema nomurai (NnNV), a giant venomous scyphozoan from China, for the first time, using in vivo models with inhibitors. NnNV was able to induce remarkable myotoxicity including significant muscle swelling, increasing the content of CK and LDH in serum, stimulating inflammation of muscle tissue, and destroying the structure of muscle tissue. In addition, the metalloproteinase inhibitors BMT and EDTA significantly reduced the myotoxicity induced by NnNV. Moreover, BMT and EDTA could decrease the inflammatory stimulation and necrosis of muscle tissue caused by the venom. These observations suggest that the metalloproteinase components of NnNV make a considerable contribution to myotoxicity. This study contributes to understanding the effector molecules of muscle injury caused by jellyfish stings and suggests a new idea for the treatment of scyphozoan envenomation.

Effects of prolonged fasting on levels of metabolites, oxidative stress, immune-related gene expression, histopathology, and DNA damage in the liver and muscle tissues of rainbow trout (Oncorhynchus mykiss).

This study was conducted to assess the impacts of prolonged fasting (70 and 120days) on the morphological, biochemical, oxidative stress responses, immune-related gene expression, histopathology, and DNA damage in rainbow trout. Final weight (FW), hepatosomatic index (HSI), and condition factor (CF) significantly decreased in both 70 and 120days of fasting compared to the pre-fasting group (p < 0.05). Fasting led to a significant reduction in serum blood metabolites (glucose, total protein, triglyceride, T. cholesterol, high-density lipoprotein (HDL), and low-density lipoprotein (LDL)) and endogenous reserves (protein and lipid). However, plasma acetylcholinesterase (AChE) activity, aspartate aminotransferase (AST), alanine aminotransferase (ALT), interleukin (IL1), tumor necrosis factor (TNF1α), and transferrin (TF) increased significantly (p < 0.05). While malondialdehyde (MDA) levels compared to the pre-fasting group increased in the liver and muscle tissues (70 and 120days), glutathione (GSH) enzyme activities decreased significantly in both tissues (p < 0.05). Histopathologically, both fasting groups (70 and 120days) when compared to the pre-fasting group led to steatosis, necrosis and degeneration in hepatocytes, inflammation and hyperemia in the liver tissue and hyaline degeneration, atrophy, and inflammation in muscle tissue. Additionally, 8-OHdG levels of the liver and muscle tissues at 120days' fasting were more severe according to 70days' fasting. Finally, blood, the liver, and muscle tissues may be helpful to assess the impacts of fasting and fasting stress in rainbow trout.

Baseline Characteristics of Participants in a Randomized Controlled Trial of Metformin for Frailty Prevention

We are conducting a double-blind, randomized controlled trial of metformin for frailty prevention. Participants are adults aged 65+ years with pre-diabetes assessed by 2-hour oral glucose tolerance test (OGTT). Those who are frail (Fried criteria) are excluded. Participants are randomized to metformin (maximum dose of 2,000 mg/day) vs. placebo and followed for 2 years. The primary outcome is frailty (category and score); secondary outcomes are physical performance and function (short physical performance battery, 6-minute walk, lower extremity strength), systemic and skeletal muscle tissue inflammation, muscle insulin signaling, insulin sensitivity (insulin clamp), glucose tolerance (OGTT), and body composition (dual-energy x-ray absorptiometry). Safety assessments occur every 3 months; frailty, systemic inflammation, and OGTT are assessed at baseline and every 6 months, and insulin clamp with muscle biopsies are assessed at baseline and every 12 months. To date, 85 subjects have been randomized; 120 completers are planned. Mean age is 72.8 ± 5.7 years, 55.3% are male, and 43.5% were Hispanic. Mean BMI is 30.2±5.8 kg/m2, waist circumference is 104.4 ±15.5 cm, fasting glucose is 102.3 ± 10.0 mg/dL, Hemoglobin A1c is 5.8 ±0.3, and glucose at 2 hours during OGTT is 167.3 ± 17.8 mg/dL. Metformin is being examined in this study as a potential therapeutic agent to prevent frailty in older adults with pre-diabetes. Findings from this trial may have future implications for the screening and potential treatment of pre-diabetes in older patients with metformin for the prevention of frailty.

A novel nitroalkene vitamin E analogue inhibits the NLRP3 inflammasome and protects against inflammation and glucose intolerance triggered by obesity

Chronic metabolic diseases, like obesity, type II diabetes and atherosclerosis often involve a low-grade and sterile systemic inflammatory state, in which activation of the pro-inflammatory transcription factor NF-kB and the NLRP3 inflammasome play a major role. It is well established that genetic inhibition of the NLRP3 inflammasome ameliorates acute and chronic inflammation. Indeed, accumulating experimental evidences in murine models and also in humans suggest that inhibition of the NLRP3 inflammasome might be a suitable approach to tackle the deleterious effects of chronic metabolic diseases. In this work, we explored our previously synthesized nitroalkene-Trolox™ derivative named NATx0, as a non-conventional anti-inflammatory strategy to treat chronic inflammatory diseases, such as obesity-induced glucose intolerance. We found that NATx0 inhibited NF-kB nuclear translocation and pro-inflammatory gene expression in macrophages in vitro. In addition, treatment with NATx0 prevented NLRP3 inflammasome activation after LPS/ATP stimulation in macrophages in vitro. When tested acutely in vivo, NATx0 inhibited neutrophil recruitment in zebrafish larvae, and also diminished IL-1β production after LPS challenge in mice. Finally, when NATx0 was administered chronically to diet-induced obese mice, it decreased muscle tissue inflammation and glucose intolerance, leading to improved glucose homeostasis. In conclusion, we propose that this novel nitroalkene-Trolox derivative is a suitable tool to tackle acute and chronic inflammation in vitro and in vivo mainly due to inhibition of NF-kB/NLRP3 activation.

Emerging therapeutics in idiopathic inflammatory myopathy

Idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of systemic autoimmune diseases characterized mainly by inflammation of muscle tissue. Although IIM traditionally encompasses polymyositis, dermatomyositis (DM), and inclusion body myositis, the disease concept has been changing in association with progress in diagnostic techniques. Thus, the new disease entities of amyopathic DM (ADM) or clinically ADM and immune-mediated necrotizing myopathy have been recognized recently. Because of the variety of symptoms or low prevalence or difficulty in correct evaluation of muscle strength and function in IIM patients, no standard treatment strategies have been established yet. Currently, glucocorticoids remain the first line of treatment of IIMs, but in addition to these, several other immunosuppressive agents or intravenous immunoglobulin have been used in a variety of different combinations. However, due to clinical heterogeneity of these conditions as well as the number of therapeutic target organs, IIM therapy remains challenging, and refractory cases are especially difficult to treat. In recent years, new therapeutic approaches using biologics or Janus kinase inhibitors, plasma exchange therapy, and other agents have been evaluated for IIMs. However, validation of the efficacy of these new treatment options remains an issue to be resolved. In this article, the author reviews current treatment strategies and new emerging therapies for IIM patients.

A RANDOMIZED CONTROLLED TRIAL OF METFORMIN FOR FRAILTY PREVENTION: STUDY DESIGN AND BASELINE CHARACTERISTICS

Inflammation and insulin resistance are major predictors of frailty. Here we describe the study design of an ongoing double-blind, randomized controlled trial of metformin for frailty prevention. Subjects are adults aged 65+ years with pre-diabetes assessed by 2-hour oral glucose tolerance test (OGTT). Those who are frail (Fried criteria) are excluded. Participants are randomized to metformin (maximum dose of 2,000 mg/day) vs. placebo and followed for 2 years. The primary outcome is frailty (category and score); secondary outcomes are physical performance and function (short physical performance battery, 6-minute walk, lower extremity strength), systemic and skeletal muscle tissue inflammation, muscle insulin signaling, insulin sensitivity (insulin clamp), glucose tolerance (OGTT), and body composition (dual-energy x-ray absorptiometry). Safety assessments occur every 3 months; frailty, systemic inflammation, and OGTT are assessed at baseline and every 6 months, and insulin clamp with muscle biopsies are assessed at baseline and every 12 months. To date, 51 subjects have been randomized; 120 completers are planned. Mean age is 73.4 ±5.7 years, 43% are female, and 39% Hispanic. Mean BMI is 30.5 ±5.5 kg/m2, waist circumference is 105 ±13.1 cm, fasting glucose is 102.3 ±8.8 mg/dL, Hemoglobin A1c is 5.8 ±0.3, and glucose at 2 hours during OGTT is 168.5 ±20.4 mg/dL. Metformin is being examined in this study as a potential therapeutic agent to prevent frailty in older adults with pre-diabetes. Findings from this trial may have future implications for the screening and potential treatment of pre-diabetes in older patients with metformin for the prevention of frailty.

Rationale and Study Design of a Randomized Clinical Trial of Metformin to Prevent Frailty in Older Adults With Prediabetes.

Frailty is a geriatric syndrome that leads to poor health outcomes with aging. Previous studies have demonstrated that insulin resistance and inflammation predict frailty onset. Metformin is a widely used, well-tolerated drug that improves insulin sensitivity and displays anti-inflammatory properties. It is also known to prevent diabetes onset in adults with prediabetes. We hypothesize that metformin in older adults with prediabetes will promote healthy aging and prevent frailty. Here we describe an ongoing placebo-controlled, double-blinded clinical trial of metformin for the prevention of frailty in older adults with prediabetes. Older adults aged more than 65 years are randomized to metformin or placebo and are followed for 2 years. Prediabetes, required for inclusion, is assessed by 2-hour oral glucose tolerance test. Exclusion criteria are baseline frailty (Fried criteria), diabetes, dementia, untreated depression, active malignancy, or severe cardiovascular, pulmonary, and neurologic diseases. Primary outcome is frailty; secondary outcomes are physical function (Short Physical Performance Battery), systemic and skeletal muscle tissue inflammation, muscle insulin signaling, insulin sensitivity (insulin clamp), glucose tolerance (oral glucose tolerance test), and body composition (dual-energy x-ray absorptiometry). Subjects are followed every 3 months for safety assessments and every 6 months for frailty assessment (Fried criteria) and oral glucose tolerance test, and every 12 or 24 months for secondary outcomes. Enrollment of 120 subjects (completers) will take place over a 2-year period. Metformin is being examined in this study as a potential therapeutic agent to prevent frailty in older adults with prediabetes. Findings from this trial may have future implications for the screening and potential treatment of prediabetes in older patients with metformin for the prevention of frailty.

Diagnostic value of diffusion-weighted MRI for imaging synovitis in pediatric patients with inflammatory conditions of the knee joint.

Diffusion-weighted imaging (DWI) of synovitis has been suggested as a possible non-invasive alternative to contrast-enhanced T1w imaging (ce-T1w). We aimed to study DWI for diagnosing synovitis in the knee joint of pediatric patients, to quantify inter-observer agreement on DWI and ce-T1w and to calculate quantitative measures of synovial diffusivity and conspicuity. Forty consecutive patients with known or suspected arthritis of the knee (25 girls, median age 12years) underwent routine 1.5T MRI with ce-T1w and transverse DWI with b values 50 and 800s/mm2. Mean apparent diffusion coefficient (ADC) values and signal intensity of inflamed synovium, joint effusion and muscle were measured with regions of interest retrospectively. Post-contrast T1w images (diagnostic standard) and diffusion-weighted images at b = 800s/mm2 with ADC map were separately rated by three independent and blinded readers with different levels of expertise for the presence and degree of synovitis along with the level of diagnostic confidence. Thirty-one (78%) patients showed at least some synovial contrast enhancement, 17 (43%) children were diagnosed with synovitis on ce-T1w. Ratings by the 1st reader on ce-T1w and on DWI for synovitis showed very good agreement (kappa = 0.90). Inter-observer agreement on DWI ranged from moderate to substantial with kappa values between 0.68 and 0.79 (all P < 0.001). Agreement and diagnostic confidence were generally lower in patients with mild and without synovial enhancement, compared to patients with synovitis. DWI yielded higher signal of inflamed synovium vs. muscle tissue, but lower signal vs. joint effusion, compared to ce-T1w (all P < 0.001). Diffusion-weighted imaging is a promising, though reader-dependent alternative to contrast-enhanced imaging in patients with arthritis of the knee, based on our preliminary findings. It holds potential for increasing patient safety and comfort.

MicroRNA-381 reduces inflammation and infiltration of macrophages in polymyositis via downregulating HMGB1.

The downregulation of microRNA (miR)-381 has been detected in various diseases. The present study aimed to investigate the effects, and underlying mechanisms of miR-381 on inflammation and macrophage infiltration in polymyositis(PM). A mouse model of experimental autoimmune myositis (EAM) was generated in this study. Hematoxylin and eosin staining was conducted to detect the inflammation of muscle tissues. In addition, ELISA and immunohistochemistry were performed to determine the expression levels of associated factors, and reverse transcription-quantitative polymerase chain reaction and western blotting were used to detect the expression levels of related mRNAs and proteins. A luciferase activity assay was used to confirm the binding of miR-381 and high mobility group box1 (HMGB1) 3'untranslated region. Transwell assays were also performed to assess the migratory ability of macrophages. The results demonstrated that serum creatine kinase(s-CK), HMGB1 and cluster of differentiation(CD)163 expression in patients with PM were increased compared within healthy controls. Conversely, the expression levels of miR-381 were downregulated in patients with PM. Furthermore, high HMGB1 expression was associated with poor survival rate in patients with PM. In the mouse studies, muscle inflammation and CD163 expression were decreased in the anti-IL-17 and anti-HMGB1 groups, compared with in the EAM model group. The expression levels of s-CK, HMGB1, IL-17 and intercellular adhesion molecule (ICAM)-1 were also downregulated in response to anti-IL-17 and anti-HMGB1. These findings indicated that HMGB1 was closely associated with inflammatory responses. In addition, the present study indicated that transfection of macrophages with miR-381 mimics reduced the migration of inflammatory macrophages, and the expression levels of HMGB1, IL-17 and ICAM-1. Conversely, miR-381 inhibition exerted the opposite effects. The effects of miR-381 inhibitors were reversed by HMGB1 small interfering RNA. In conclusion, miR-381 may reduce inflammation and the infiltration of macrophages; these effects were closely associated with the downregulation of HMGB1.

Effect of whole-body electromyostimulation and / or protein supplementation on obesity and cardiometabolic risk in older men with sarcopenic obesity: the randomized controlled FranSO trial

BackgroundSarcopenic Obesity (SO) is characterized by low lean and high fat mass; i.e. from a functional aspect a disproportion between engine (muscle) and mass to be moved (fat). At present, most research focuses on the engine, but the close “cross talk” between age-associated adipose and skeletal muscle tissue inflammation calls for comprehensive interventions that affect both components alike. Protein and exercise are likely candidates, however with respect to the latter, the enthusiasm for intense and frequent exercise is rather low, especially in functionally limited older people. The aim of this study was therefore to evaluate the effect of whole-body electromyostimulation (WB-EMS), a time-efficient, joint-friendly and highly customizable exercise technology, on obesity parameters and cardiometabolic risk in men with SO.MethodsOne-hundred community-dwelling (cdw) Bavarian men ≥70 years with SO were randomly assigned to either (a) whey protein supplementation (WPS), (b) WB-EMS and protein supplementation (WB-EMS&P) or (c) non-intervention control (CG). Protein supplementation contributed to an intake of 1.7–1.8 g/kg/body mass/d, WB-EMS consisted of 1.5 × 20 min/week (85 Hz, 350 μs, 4 s of strain–4 s of rest) with moderate-high intensity. Using an intention to treat approach with multiple imputation, the primary study endpoint was total body fat mass (TBF), secondary endpoints were trunk fat mass (TF), waist circumference (WC) and total-cholesterol/HDL-cholesterol ratio (TC/HDL-C).ResultsAfter 16 weeks of intervention, TBF was reduced significantly in the WPS (− 3.6 ± 7.2%; p = 0.005) and WB-EMS&P (− 6.7 ± 6.2%; p < 0.001), but not in the CG (+ 1.6 ± 7.1%; p = 0.191). Changes in the WB-EMS&P (p < 0.001) and the WPS group (p = 0.011) differ significantly from the CG. TF decreased in the WB-EMS&P (p < 0.001) and WPS (p = .117) and increased in the CG (p = .159); WC decreased significantly in the treatment groups and was maintained in the CG. Lastly, the TC/HDL-C ratio improved significantly in the WB-EMS&P and WPS group and was maintained in the CG. Significant differences between WB-EMS&P and WPS were determined for waist circumference only (p = 0.015; TBF: p = 0.073; TF: p = 0.087; TC/HDL-C: p = .773).ConclusionModerate-high dosed whey protein supplementation, especially when combined with WB-EMS, may be a feasible choice to address obesity and cardiometabolic risk in older cdw men with SO unable or unmotivated to exercise conventionally.Trial registration numberClinicalTrials.govNCT02857660; registration date: 05/01/2017.

Immunoglobulin therapy ameliorates the phenotype and increases lifespan in the severely affected dystrophin-utrophin double knockout mice.

Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder, caused by mutations in the dystrophin gene, affecting 1:3500-5000 boys worldwide. The lack of dystrophin induces degeneration of muscle cells and elicits an immune response characterized by an intensive secretion of pro-inflammatory cytokines. Immunoglobulins modulate the inflammatory response through several mechanisms and have been widely used as an adjuvant therapy for autoimmune diseases. Here we evaluated the effect of immunoglobulin G (IG) injected intraperitoneally in a severely affected double knockout (dko) mouse model for Duchenne muscular dystrophy. The IG dko treated mice were compared regarding activity rates, survival and histopathology with a control untreated group. Additionally, dendritic cells and naïve lymphocytes from these two groups and WT mice were obtained to study in vitro the role of the immune system associated to DMD pathophysiology. We show that IG therapy significantly enhances activity rate and lifespan of dko mice. It diminishes muscle tissue inflammation by decreasing the expression of costimulatory molecules MHC, CD86 and CD40 and reducing Th1-related cytokines IFN-γ, IL-1β and TNF-α release. IG therapy dampens the effector immune responses supporting the hypothesis according to which the immune response accelerates DMD progression. As IG therapy is already approved by FDA for treating autoimmune disorders, with less side-effects than currently used glucocorticoids, our results may open a new therapeutic option aiming to improve life quality and lifespan of DMD patients.

The immunoproteasomes are key to regulate myokines and MHC class I expression in idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIMs) are diseases with muscle weakness, morphologically characterized by inflammatory infiltration and increased expression of MHC class I molecule on myofibers. Immunoproteasome, as a proteolytic complex that shapes the repertoire of antigenic peptides, has been previously demonstrated to be over-expressed in IIMs at mRNA level. In this study, we investigated the expression and the function of the immunoproteasome in IIMs in more detail. As shown by immunofluorescence staining, expression of relevant players of the immunoproteasome was detectable in the inflamed skeletal muscle tissue from IIM patients. In fact, two subunits of the immunoproteasome, β1i or β5i were upregulated in sporadic inclusion body myositis, immune-mediated necrotizing myopathies and dermatomyositis muscle biopsies and co-localized with the MHC class I expressing myofibers. Double immunofluorescence revealed that both myofibers and muscle infiltrating cells, including CD8+ T-cells and CD68 + macrophages in IIMs expressed β1i or β5i. In addition, we have also investigated the role of the immunoproteasome in myoblasts during in vitro inflammatory conditions. Using human primary myoblasts cultures we found that pro-inflammatory cytokines, TNF-α or IFN-γ upregulate β1i or β5i. Selective inhibition or depletion of β5i amplified the TNF-α or IFN-γ mediated expression of cytokines/chemokines (myokines) in myoblasts. Furthermore, we demonstrated that specific inhibitors of β1i or β5i reduced the cell surface expression of MHC class I in myoblasts induced by IFN-γ. Taken together, our data suggest that the immunoproteasome is involved in pathologic MHC class I expression and maintenance of myokine production in IIMs. Thus, induction of the immunoproteasome was identified as a pathomechanism underlying inflammation in IIMs.

Scanning for Therapeutic Targets within the Cytokine Network of Idiopathic Inflammatory Myopathies

The idiopathic inflammatory myopathies (IIM) constitute a heterogeneous group of chronic disorders that include dermatomyositis (DM), polymyositis (PM), sporadic inclusion body myositis (IBM) and necrotizing autoimmune myopathy (NAM). They represent distinct pathological entities that, most often, share predominant inflammation in muscle tissue. Many of the immunopathogenic processes behind the IIM remain poorly understood, but the crucial role of cytokines as essential regulators of the intramuscular build-up of inflammation is undisputed. This review describes the extensive cytokine network within IIM muscle, characterized by strong expression of Tumor Necrosis Factors (TNFα, LTβ, BAFF), Interferons (IFNα/β/γ), Interleukins (IL-1/6/12/15/18/23) and Chemokines (CXCL9/10/11/13, CCL2/3/4/8/19/21). Current therapeutic strategies and the exploration of potential disease modifying agents based on manipulation of the cytokine network are provided. Reported responses to anti-TNFα treatment in IIM are conflicting and new onset DM/PM has been described after administration of anti-TNFα agents to treat other diseases, pointing to the complex effects of TNFα neutralization. Treatment with anti-IFNα has been shown to suppress the IFN type 1 gene signature in DM/PM patients and improve muscle strength. Beneficial effects of anti-IL-1 and anti-IL-6 therapy have also been reported. Cytokine profiling in IIM aids the development of therapeutic strategies and provides approaches to subtype patients for treatment outcome prediction.