Cross-talk between NADPH oxidase-PKCa-p 38 MAPK and NF-jB-MT1MMP in activating proMMP-2 by ET-1 in pulmonary artery smooth muscle cells Jaganmay Sarkar 1 • Animesh Chowdhury 1 • Tapati Chakraborti 1 • Sajal Chakraborti 1 Received: 12 December 2015 / Accepted: 17 February 2016 / Published online: 24 February 2016 Ó Springer Science+Business Media New York 2016 Abstract Treatment of bovine pulmonary artery smooth muscle cells with endothelin-1 (ET-1) caused an increase in the expression and activation of proMMP-2 in the cells. The present study was undertaken to determine the underlying mechanisms involved in this scenario. We demonstrated that (i) pretreatment with NADPH oxidase inhibitor, apocynin; PKC-a inhibitor, Go6976; p 38 MAPK inhibitor SB203580 and NF-jB inhibitor, Bay11-7082 inhibited the expression and activation of proMMP-2 induced by ET-1; (ii) ET-1 treatment to the cells stimulated NADPH oxidase and PKCa activity, p 38 MAPK phospho- rylation as well as NF-jB activation by translocation of NF-jBp65 subunit from cytosol to the nucleus, and sub- sequently by increasing its DNA-binding activity; (iii) ET- 1 increases MT1-MMP expression, which was inhibited upon pretreatment with apocynin, Go6976, SB293580, and Bay 11-7082; (iv) ET-1 treatment to the cells downregu- lated TIMP-2 level. Although apocynin and Go6976 pre- treatment reversed ET-1 effect on TIMP-2 level, yet pretreatment of the cells with SB203580 and Bay 11-7082 did not show any discernible change in TIMP-2 level by ET-1. Overall, our results suggest that ET-1-induced acti- vation of proMMP-2 is mediated via cross-talk between NADPH oxidase-PKCa-p 38 MAPK and NFjB-MT1MMP signaling pathways along with a marked decrease in TIMP- 2 expression in the cells. Keywords proMMP-2 Á MT1-MMP Á p 38 MAPK Á NF-jB Á TIMP-2 Á PKC-a Á NADPH oxidase Abbreviation SMC Smooth muscle cell proMMP-2 Pro matrix metalloprotease 2 MT1-MMP Membrane type 1 matrix metalloprotease TIMP-2 Tissue inhibitor of matrix metalloprotease 2 PKC-a Protein kinase C a IKK Inhibitory jB kinase NF-jB Nuclear factor jB, IjB-a, inhibitory jBa Introduction Pulmonary hypertension (PAH) is characterized by per- sistent vasoconstriction and remodeling of pulmonary arteries, which decreases the cross-sectional area of pul- monary microvasculature and increases the vascular resis- tance. As a result, elevation of pulmonary arterial pressure (Ppa) occurs that further increases the right ventricular afterload leading to right ventricular hypertrophy and failure [1]. The pulmonary vascular remodeling process involves marked increase in extracellular matrix (ECM) turnover, as well as accumulation of ECM proteins. In the setting of PAH, an imbalance in ECM synthesis and degradation has great importance and that contributes to the complexity of the pathological remodeling process [2, 3]. Degradation of ECM could be orchestrated by several types of proteases, where matrix metalloproteinases (MMPs) are most important [4, 5]. Among the MMPs, matrix metalloproteinase-2 (MMP-2) is the best studied enzyme because of their role in the pathogenesis of various types of diseases, e.g., PAH. MMP-2 is mainly produced as an inactive proenzyme (proMMP-2), which is activated by Electronic supplementary material The online version of this article (doi:10.1007/s11010-016-2673-6) contains supplementary material, which is available to authorized users. & Sajal Chakraborti saj_chakra@rediffmail.com; sajal_chakraborti@yahoo.com 1 Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, West Bengal 741235, India 123 Mol Cell Biochem (2016) 415:13–28 DOI 10.1007/s11010-016-2673-6