TGF‐β1 and HtrA1 interactive pathway in the molecular progression of osteoarthritis (1139.9)

Abstract

Prior research has indicated that a pathway exists in the molecular progression of Osteoarthritis (OA) involving key biomarkers HtrA1, Ddr‐2 and Mmp‐13. We and others have recently shown, by immunohisotchemical staining, that HtrA1 and TGF‐β1 show a unique, inverse relationship in OA. The objective of this research is to provide supporting data and clarification to this interaction via Enzyme‐Linked Immunosorbent Assay (ELISA) and quantitative Polymerase Chain Reaction (qPCR) analysis. Cartilage samples from the hip and synovial fluid samples form the knee of wild type (WT) mice, treated to induce OA, were assayed for quantitative presence of TGF‐β1 biomarker using ELISA and quantitative mRNA presence using qRTPCR. We observed initially high levels of TGF‐β1 protein that subsequently decreased 50% as OA progressed and became more severe over time. We hypothesize that TGF‐β1, as a cytokine growth factor, is over expressed in early OA resulting in an increased expression of HtrA1, a serine protease, which subsequently impairs TGF‐β1 cell maintenance activity and dooms the cell to apoptosis.