Secretome analysis of human articular chondrocytes unravels catabolic effects of nicotine on the joint

Purpose: Osteoarthritis (OA) is a degenerative joint pathology characterized by articular cartilage degradation that lacks from efficient therapy. Since previous epidemiological data show a high controversy regarding the role of smoking in OA, we aimed to evaluate the effects of nicotine (the most physiologically active compound of tobacco) on the joint. Experimental design: Secretome analyses, based onmetabolic labeling followed by LC-MALDI-TOF/TOF analysis, were carried out using an in vitromodel of articular inflammation (primary human articular chondrocytes treated with interleukin-1 beta), and also on osteoarthritic cells. ELISA and Western blot assays were performed to verify some of the results. Results: Nineteen proteins were altered by nicotine in the model of articular inflammation, including several cytokines and proteases. We confirmed the increased secretion by nicotine of matrix metalloproteinase 1 and two proposed markers of OA, fibronectin, and chitinase 3-like protein 1. Finally, four components of the extracellular matrix of cartilage were decreased by nicotine in OA chondrocytes. Conclusions and clinical relevance: Our data contribute to a better understanding of the molecular mechanisms that are modulated by nicotine in cartilage cells, suggesting a negative effect of this drug on the joint.