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Gene expression of proinflammatory cytokines in muscle biopsies of patients with dermatomyositis/polymyositis: correlation with clinical and laboratory features and outcome

Grant number: 12/09633-3
Support type:Regular Research Grants
Duration: August 01, 2012 - July 31, 2014
Field of knowledge:Health Sciences - Medicine - Medical Clinics
Principal researcher:Samuel Katsuyuki Shinjo
Grantee:Samuel Katsuyuki Shinjo
Home Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Assoc. researchers:Miyuki Uno ; Sueli Mieko Oba Shinjo ; Suely Kazue Nagahashi Marie


Dermatomyositis (DM) and polymyositis (PM) are a heterogeneous group of chronic systemic autoimmune myopathy associated with high morbidity and functional disability.From the point of immunopathological view, there are primarily CD8 (+) lymphocyte and macrophage infiltrations in the PM muscle fibers. These fibres express high levels of class I MHC antigens and release perforin granules, resulting in lysis of the muscle fibers. In DM, B cells play an important role in the pathogenesis of disease by the autoantibody presence, immune complex deposition in dermoepiderme junction of skin lesions, and B cells presence in inflammated muscles and perivascular areas. Additionally, deposition of complement and immunoglobulin in perifascicular endothelium may lead to ischemia and muscle atrophy, showing the importance of humoral immunity.The activation, chemotaxis and invasion of these immune system cells in muscle tissues as well as the amplification of the inflammatory process, are mediated by various cytokines and chemokines present locally, which, in turn, are produced by the immune cells, endothelial cells and muscle fibers.Based on the immunopathogenesis of DM/PM, the study of pro-inflammatory cytokines (and other proteins) is important to better understand the molecular mechanisms involved in muscle tissue damage and their correlation with clinical and laboratory disease manifestations, as well as the evolution and prognosis of patients with DM/PM.In the present study, 50 muscle biopsies routinely performed for investigation and diagnosis of DM/PM patients from the Service will be analyzed. Additional to the demographic, clinical and laboratory data, gene expression analysis will be performed. Total RNA will be extracted from stored muscle tissue and will be reversely transcribed into cDNA.The expression levels of genes involved in inflammatory process, ischemia, and muscle atrophy will be analyzed by quantitative real time PCR and compared with age and gender-matched control samples (muscle biopsy with normal morphological features). The reactions will be performed using primers for each gene by the method of Sybr Green incorporation. The primers will be designed in different exons to avoid nonspecific DNA amplification. Quantitative data will be normalized relative to constitutive genes as internal controls. The equation 2-DDCt will be used to calculate the relative expression of genes in the muscle samples from patients compared to normal samples. Relative gene expression data will be correlated with clinical and laboratory data, clinical evaluation and the degree of impairment and inflammatory infiltrate in muscle tissue. (AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
PAMPLONA DA SILVA, THIAGO COSTA; SILVA, MARILDA GUIMARAES; SHINJO, SAMUEL KATSUYUKI. Relevance of serum angiogenic cytokines in adult patients with dermatomyositis. ADVANCES IN RHEUMATOLOGY, v. 58, JUL 31 2018. Web of Science Citations: 1.
SAMUEL KATSUYUKI SHINJO; SUELI MIEKO OBA-SHINJO; MIYUKI UNO; SUELY KAZUE NAGAHASHI MARIE. The expression of gene ANKRD1 correlates with hypoxia status in muscle biopsies of treatment-näive adult dermatomyositis. MedicalExpress (São Paulo, online), v. 4, n. 4, p. -, Ago. 2017.

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