Effects Of HIV Protease Inhibitor On Progress Of Neointimal Hyperplasia Of Mice Carotid Wire-injury Model

Background:HPIs(HIV protease inhibitors) have shown to inhibit inflammation response in different disease models as well as inhibition of the smooth muscle cell proliferation pathway. Previously work showed Saquinavir could highly inhibit recombinant Cathepsin V(homogeneous to mouse Cathepsin L) activity. Neointimal hyperplasia is known as a chronic inflammation process. We raised the hypothesis that HIV Protease inhibitor Saquinavir/Ritonavir attenuate neointimal hyperplasia through suppressing TLRs related Cathepsin L/V Activation.Methods and Results:3days before and daily after carotid wire-injuy treatment with first-generation HPI Saquinavir5mg/kg combine Ritonavir1.25mg/kg significantly attenuate I/M ratio on day28as well as decreased SMC content. A significant increase of Cathepsin L activity and expression after carotid injury was detected using RT-PCR, Cathepsin L activity assay and immunofluorescence, which could be suppressed with SQV treatment. TLRs deficiency mice also showed significant decrease of Cathepsin-L activity on day7after wire-injury. Further use of Cathepsin L deficiency mice revealed a44.5%decrease of neointimal lesion compared to Cathepsin L+/+mice. In vitro study, SQV inhibit LPS induced Catehpsin V expression in THP-1cells. TLRs agonist LPS and HMGB1were also used to induce THP-1adhesion to HUVECs, smooth muscle cell proliferation(MTS) and migration(Wound healing assay), peritoneal macrophage TNF-a release(Elisa), MCP-1expression in HUVECs and HUASMC(Western blot), SQV treatment could significantly block those vascular cell response. Cathepsin V silence in human smooth muscle cells also show a significant decrease in proliferation and Wound-healing migration rates as well as MMP-2expression.Conclusion:Those findings support the ability of SQV/RTV to interfere with neointimal formation by directly or indirectly inhibiting Cathepsin L and TLRs-Cathesin L activation and consequently inhibiting macrophage activation, monocyte adhesion and smooth muscle cell proliferation,migration.