Heparin antiproliferative activity on bovine pulmonary artery smooth muscle cells requires both N-acetylation and N-sulfonation

The antiproliferative activity of Heparin (HP) on bovine pulmonary artery smooth muscle cells (BPASMC) in vitro requires both N-acetylation and N-sulfonation. This was demonstrated by quantifying the relative N-acetylation of three commercial heparins of known antiproliferative activities, using their Fourier-transform infrared (FTIR) band areas at 1381-1378 and 1320-1317 cm(-1), which combined resulted in 1.0, 1.0 and 1.3 cm2 for Choay, Elkins-Sinn and Upjohn HP, respectively. These results show that Upjohn HP, which is at least 44% more antiproliferative than the other two, is 30% more N-acetylated. Upjohn HP was also N-desulfonated chemically, and its antiproliferative activity was determined. Its total sulfonate (--SO 3 -) content (O- and N-sulfonate) was quantified using the FTIR band area at 1260-1200 cm(-1) for the S=O stretching; a drop in sulfonate content from 21.87% (w/w) before N-desulfonation to 16.51% (w/w) after N-desulfonation, resulted in a 67% decrease in its inhibitory potency. In addition to the requirement that approximately 24% of the sulfonate content be bonded to N, the data show a direct correlation between the extent of Upjohn HP N-acetylation and its antiproliferative activity on BPASMC.     

Role of Spm–Cer‐S1P signalling pathway in MMP‐2 mediated U46619‐induced proliferation of pulmonary artery smooth muscle cells: protective role of epigallocatechin‐3‐gallate

During remodelling of pulmonary artery, marked proliferation of pulmonary artery smooth muscle cells (PASMCs) occur s , which contributes to pulmonary hypertension. Thromboxane A₂ (TxA₂) has been shown to produce pulmonary hypertension. The present study investigates the inhibitory effect of epigallocatechin‐3‐gallate (EGCG) on the TxA₂ mimetic, U46619‐induced proliferation of PASMCs. U46619 at a concentration of 10 nM induces maximum proliferation of bovine PASMCs. Both pharmacological and genetic inhibitors of p³⁸MAPK, NF‐κB and MMP‐2 significantly inhibit U46619‐induced cell proliferation. EGCG markedly abrogate U46619‐induced p³⁸MAPK phosphorylation, NF‐κB activation, proMMP‐2 expression and activation, and also the cell proliferation. U46619 causes an increase in the activation of sphingomyelinase (SMase) and sphingosine kinase (SPHK) and also increase sphingosine 1 phosphate (S1P) level. U46619 also induces phosphorylation of ERK1/2, which phosphorylates SPHK leading to an increase in S1P level. Both pharmacological and genetic inhibitors of SMase and SPHK markedly inhibit U46619‐induced cell proliferation. Additionally, pharmacological and genetic inhibitors of MMP‐2 markedly abrogate U46619‐induced SMase activity and S1P level. EGCG markedly inhibit U46619‐induced SMase activity, ERK1/2 and SPHK phosphorylation and S1P level in the cells. Overall, Sphingomyeline–Ceramide–Sphingosine‐1‐phosphate (Spm–Cer–S1P) signalling axis plays an important role in MMP‐2 mediated U46619‐induced proliferation of PASMCs. Importantly, EGCG inhibits U46619 induced increase in MMP‐2 activation by modulating p³⁸MAPK–NFκB pathway and subsequently prevents the cell proliferation. Copyright © 2015 John Wiley & Sons, Ltd.