Molecular alterations in skeletal muscle in rheumatoid arthritis are related to disease activity, physical inactivity, and disability.

Abstract

BACKGROUND: To identify molecular alterations in skeletal muscle in rheumatoid arthritis (RA) that may contribute to ongoing disability in RA. METHODS: Persons with seropositive or erosive RA (n = 51) and control subjects matched for age, gender, race, body mass index (BMI), and physical activity (n = 51) underwent assessment of disease activity, disability, pain, physical activity and thigh muscle biopsies. Muscle tissue was used for measurement of pro-inflammatory markers, transcriptomics, and comprehensive profiling of metabolic intermediates. Groups were compared using mixed models. Bivariate associations were assessed with Spearman correlation. RESULTS: Compared to controls, patients with RA had 75% greater muscle concentrations of IL-6 protein (p = 0.006). In patients with RA, muscle concentrations of inflammatory markers were positively associated (p < 0.05 for all) with disease activity (IL-1β, IL-8), disability (IL-1β, IL-6), pain (IL-1β, TNF-α, toll-like receptor (TLR)-4), and physical inactivity (IL-1β, IL-6). Muscle cytokines were not related to corresponding systemic cytokines. Prominent among the gene sets differentially expressed in muscles in RA versus controls were those involved in skeletal muscle repair processes and glycolytic metabolism. Metabolic profiling revealed 46% higher concentrations of pyruvate in muscle in RA (p < 0.05), and strong positive correlation between levels of amino acids involved in fibrosis (arginine, ornithine, proline, and glycine) and disability (p < 0.05). CONCLUSION: RA is accompanied by broad-ranging molecular alterations in skeletal muscle. Analysis of inflammatory markers, gene expression, and metabolic intermediates linked disease-related disruptions in muscle inflammatory signaling, remodeling, and metabolic programming to physical inactivity and disability. Thus, skeletal muscle dysfunction might contribute to a viscous cycle of RA disease activity, physical inactivity, and disability.

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Published Version (Please cite this version)

10.1186/s13075-016-1215-7

Publication Info

Huffman, Kim M, Ryan Jessee, Brian Andonian, Brittany N Davis, Rachel Narowski, Janet L Huebner, Virginia B Kraus, Julie McCracken, et al. (2017). Molecular alterations in skeletal muscle in rheumatoid arthritis are related to disease activity, physical inactivity, and disability. Arthritis Res Ther, 19(1). p. 12. 10.1186/s13075-016-1215-7 Retrieved from https://hdl.handle.net/10161/13703.

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Scholars@Duke

Andonian

Brian Andonian

Assistant Professor of Medicine
Muoio

Deborah Marie Muoio

George Barth Geller Distinguished Professor of Cardiovascular Disease

Deb Muoio is professor in the Departments of Medicine and Pharmacology & Cancer Biology, George Barth Geller Distinguished Professor of Cardiovascular Disease, and Associate Director of the Duke Molecular Physiology Institute (DMPI). She is viewed nationally and internationally as a leader in the fields of diabetes, obesity, exercise physiology, and mitochondrial energy metabolism. Her laboratory investigates mechanisms of metabolic regulation, with emphasis on molecular events that link lifestyle factors such as over nutrition and physical inactivity to metabolic disorders, including obesity, diabetes, and heart failure. Her program features a translational approach that combines work in animal and cell-based models with human studies, using genetic engineering, molecular biology and mass spectrometry-based metabolomics and proteomics as tools to understand the interplay between mitochondrial physiology and cardiometabolic health. Her laboratory developed a sophisticated platform for deep and comprehensive assessment of mitochondrial bioenergetics and energy transduction. Her team is integrating this new platform with metabolomics, proteomics, and metabolic flux analysis to gain insights into mechanisms by which mitochondria modulate insulin action and metabolic resilience. She has published more than 120 papers in prominent journals such as Cell, Cell Metabolism, Circulation, Circulation Research, Diabetes, and JCI Insight. Dr. Muoio’s laboratory has enjoyed longstanding support from the NIDDK and NHLBI.

PhD, University of North Carolina, Chapel Hill, NC


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