Erfan Aref-Eshghi1, Ming Liu1, Seyd Babak Razavi-Lopez1, Kensuke Hirasawa1, Patricia E Harper1, Glynn Martin1, Andrew Furey1, Roger Green1, Guang Sun1, Proton Rahman1, Guangju Zhai2. 1. From the Discipline of Genetics, Division of Biomedical Science, Division of Orthopedics, Discipline of Medicine, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada; and the Department of Twin Research and Genetic Epidemiology, King's College London, London, UK.E. Aref-Eshghi, MD, PhD Candidate; M. Liu, MSc, Research Assistant, Discipline of Genetics; S. Razavi-Lopez, BSc, Research Assistant; K. Hirasawa, PhD, Professor, Division of Biomedical Science; P.E. Harper, BSc, Master's Student, Discipline of Genetics; G. Martin, MD, Orthopedic Surgeon; A. Furey, MD, Associate Professor of Surgery, Division of Orthopedics; R. Green*, PhD, Honorary Research Professor, Discipline of Genetics; G. Sun, PhD, Professor; P. Rahman, MD, Professor of Medicine (Rheumatology), Discipline of Medicine, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada; G. Zhai, PhD, Associate Professor, Discipline of Genetics, Faculty of Medicine, Memorial University of Newfoundland; Department of Twin Research and Genetic Epidemiology, King's College London, London, UK. 2. From the Discipline of Genetics, Division of Biomedical Science, Division of Orthopedics, Discipline of Medicine, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada; and the Department of Twin Research and Genetic Epidemiology, King's College London, London, UK.E. Aref-Eshghi, MD, PhD Candidate; M. Liu, MSc, Research Assistant, Discipline of Genetics; S. Razavi-Lopez, BSc, Research Assistant; K. Hirasawa, PhD, Professor, Division of Biomedical Science; P.E. Harper, BSc, Master's Student, Discipline of Genetics; G. Martin, MD, Orthopedic Surgeon; A. Furey, MD, Associate Professor of Surgery, Division of Orthopedics; R. Green*, PhD, Honorary Research Professor, Discipline of Genetics; G. Sun, PhD, Professor; P. Rahman, MD, Professor of Medicine (Rheumatology), Discipline of Medicine, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada; G. Zhai, PhD, Associate Professor, Discipline of Genetics, Faculty of Medicine, Memorial University of Newfoundland; Department of Twin Research and Genetic Epidemiology, King's College London, London, UK. guangju.zhai@med.mun.ca.
Abstract
OBJECTIVE: To compare SMAD3 gene expression between human osteoarthritic and healthy cartilage and to examine whether expression is regulated by the promoter DNA methylation of the gene. METHODS: Human cartilage samples were collected from patients undergoing total hip/knee joint replacement surgery due to primary osteoarthritis (OA), and from patients with hip fractures as controls. DNA/RNA was extracted from the cartilage tissues. Real-time quantitative PCR was performed to measure gene expression, and Sequenom EpiTyper was used to assay DNA methylation. Mann-Whitney test was used to compare the methylation and expression levels between OA cases and controls. Spearman rank correlation coefficient was calculated to examine the association between the methylation and gene expression. RESULTS: A total of 58 patients with OA (36 women, 22 men; mean age 64 ± 9 yrs) and 55 controls (43 women, 12 men; mean age 79 ± 10 yrs) were studied. SMAD3 expression was on average 83% higher in OA cartilage than in controls (p = 0.0005). No difference was observed for DNA methylation levels in the SMAD3 promoter region between OA cases and controls. No correlation was found between SMAD3 expression and promoter DNA methylation. CONCLUSION: Our study demonstrates that SMAD3 is significantly overexpressed in OA. This overexpression cannot be explained by DNA methylation in the promoter region. The results suggest that the transforming growth factor-β/SMAD3 pathway may be overactivated in OA cartilage and has potential in developing targeted therapies for OA.
OBJECTIVE: To compare SMAD3 gene expression between humanosteoarthritic and healthy cartilage and to examine whether expression is regulated by the promoter DNA methylation of the gene. METHODS:Humancartilage samples were collected from patients undergoing total hip/knee joint replacement surgery due to primary osteoarthritis (OA), and from patients with hip fractures as controls. DNA/RNA was extracted from the cartilage tissues. Real-time quantitative PCR was performed to measure gene expression, and Sequenom EpiTyper was used to assay DNA methylation. Mann-Whitney test was used to compare the methylation and expression levels between OA cases and controls. Spearman rank correlation coefficient was calculated to examine the association between the methylation and gene expression. RESULTS: A total of 58 patients with OA (36 women, 22 men; mean age 64 ± 9 yrs) and 55 controls (43 women, 12 men; mean age 79 ± 10 yrs) were studied. SMAD3 expression was on average 83% higher in OA cartilage than in controls (p = 0.0005). No difference was observed for DNA methylation levels in the SMAD3 promoter region between OA cases and controls. No correlation was found between SMAD3 expression and promoter DNA methylation. CONCLUSION: Our study demonstrates that SMAD3 is significantly overexpressed in OA. This overexpression cannot be explained by DNA methylation in the promoter region. The results suggest that the transforming growth factor-β/SMAD3 pathway may be overactivated in OA cartilage and has potential in developing targeted therapies for OA.
Entities:
Keywords:
CARTILAGE; DNA METHYLATION; GENE EXPRESSION; OSTEOARTHRITIS; SMAD3
Authors: Sophie Hackinger; Katerina Trajanoska; Unnur Styrkarsdottir; Eleni Zengini; Julia Steinberg; Graham R S Ritchie; Konstantinos Hatzikotoulas; Arthur Gilly; Evangelos Evangelou; John P Kemp; David Evans; Thorvaldur Ingvarsson; Helgi Jonsson; Unnur Thorsteinsdottir; Kari Stefansson; Andrew W McCaskie; Roger A Brooks; Jeremy M Wilkinson; Fernando Rivadeneira; Eleftheria Zeggini Journal: Hum Mol Genet Date: 2017-10-01 Impact factor: 6.150