Interferon and ribavirin alter matrix metalloproteinase-9 (MMP-9) activity in HIV/HCV co-infected patients and in THP-1 cells

Alan Kennedy1, Martina Hennessy1, Colm Bergin2, Fiona Mulcahy2, Susan Hopkins1, J. Paul Spiers1. 1Department of Pharmacology and Therapeutics, Trinity College Dublin, Dublin 2, Ireland, 2Department of Genito Urinary Medicine and Infectious Diseases, St James’s Hospital, Dublin 8, Ireland.

Matrix metalloproteinases (MMP’s), a group of proteolytic enzymes, are up-regulated in HIV infected patients (Mellanen et al, 2006). This increased MMP activity may have deleterious consequences resulting in immunopathology that facilitates pathogen dissemination or persistence, thus increasing morbidity or mortality (Elkington et al, 2005). Our study investigates the impact of ribavirin (RBV) and interferon (INF) therapy on MMP activity in HIV/HCV co-infected patients and seeks to determine the cellular basis for any observed effect.

Plasma was reserved from healthy controls, HIV+, HCV+ and HIV+/HCV+ co-infected patients (n = 6/group). The HIV+/HCV+ cohort were assessed at day 3 subsequent to combination therapy with RBV (1000mg/day)/INF (1.5μg/kg/wk). Human monocyte/macrophage THP-1 cells were cultured in RPMI 1640 medium with 10% FBS and antibiotics. Human hepatic stellate cells, LX-2’s, were cultured in DMEM containing identical supplements. Both cell lines were incubated in serum-free medium containing RBV (20μM), INF (500IU), RBV/INF (20μM/500IU), medium (untreated control), or phorbol 12-myrisate 13-acetate (PMA)

(50ng/ml) for 48hrs. For analysis, in all cases, samples were subjected to gelatin zymography (Song et al, 2006) with results expressed as peak height (AU: arbitrary units). Data underwent non-parametric analysis and were expressed as mean ± SE. A value of P<0.05 was taken to indicate statistical significance.

Plasma MMP-9 activity was increased in both HIV+ (109±17 AU) and HIV+/HCV+ patients (100±20 AU) compared with healthy controls (25±8 AU) and HCV+ patients (37±8 AU). RBV/ INF decreased plasma MMP-9 activity by 70% at day 3 compared with baseline (31±16 vs 100±20 AU). THP-1 cells activated with PMA showed decreased MMP-9 activity after 48hr treatment with INF and RBV/INF when compared to PMA controls (76±7.9 and 75±3.9 vs 100±3 AU). PMA activated LX-2 cells showed no significant changes in MMP-9 activity relating to INF and RBV/INF (106±9.8 and 97±5.2) but RBV alone induced an induction (148±14) in contrast to PMA controls (100±11).

In conclusion, increased MMP activity appears attributable to HIV infection in HIV/HCV co-infected patients and this activity is reduced by RBV/INF therapy. We also demonstrate that this effect is associated with inflammatory/immune cells rather than hepatic stellate cells.

Mellanen, L. et al. (2006). J. Oral. Pathol. Med. 35(9), 530-539.
Elkington, P.T.G. et al. (2005). Clin. Exp. Immunol. 142, 12-20.
Song, G. et al. (2006). Pharmacol. Res. 54(1), 57-64.

Thanks to Prof. Joseph Keane of Trinity College Dublin and Prof. Scott L. Friedman of Mount Sinai School of Medicine, New York for provision of THP-1 and LX-2 cells.