CPI-431-32 efficiently inhibits HCV and HIV-1 variants, which are normally resistant to DAAs. T-lymphocytes. Using this co-culture model, we demonstrate that cyclophilin inhibitors (CypI), including a novel cyclosporin A (CsA) analog, CPI-431-32, simultaneously inhibits replication of both HCV and Erlotinib mesylate HIV-1 when added pre- and post-infection. In contrast, the HIV-1 protease inhibitor nelfinavir or the HCV NS5A inhibitor daclatasvir only blocks the replication of a single computer virus in the co-infection system. CPI-431-32 efficiently inhibits HCV and HIV-1 variants, which are normally resistant to DAAs. CPI-431-32 is slightly, but consistently more efficacious than the most advanced clinically tested CypIalisporivir (ALV)at interrupting an established HCV/HIV-1 co-infection. The superior antiviral efficacy of CPI-431-32 over ALV correlates with its higher potency inhibition of cyclophilin A (CypA) isomerase activity and at preventing HCV NS5A-CypA and HIV-1 capsid-CypA interactions known to be vital for replication of the respective viruses. Moreover, we obtained evidence that CPI-431-32 prevents the cloaking of both the HIV-1 and HCV genomes from cellular sensors. Based on these results, CPI-431-32 has the potential, as a single agent or in combination with DAAs, to inhibit both HCV and HIV-1 infections. Introduction Since HCV and HIV share the same routes of transmission, co-infection is usually a frequent event, occurring in 5C10 million individuals worldwide [1C2]. The current primary route of exposure of both viruses is through contaminated needles. It is estimated that 50%-90% of injection drug users are infected with HCV due to the high efficiency of HCV transmission via percutaneous blood exposure [3C10]. The unfavorable impact of HIV-1 contamination on hepatitis C is well known [11C13]. HIV-1/HCV co-infection is usually associated with higher HCV viral load, persistent HCV viremia, reduced response to Erlotinib mesylate IFN alpha-based HCV treatment, and accelerated and more aggressive liver disease. Higher HCV RNA levels and chronic HCV contamination in HIV-1-infected patients are thought to be related to diminution of CD4 and CD8 T-cell responses to HCV contamination [14C16]. HIV-1-derived proteins such as tat and gp120 may mediate a hepatic cytokine milieu via binding to hepatocytes, stellate cells, and immune cell populations resident in the liver . Despite highly active antiretroviral therapy (HAART), there is an increased risk of hepatitis/liver-related deaths among co-infected drug Erlotinib mesylate users compared to HCV-mono-infected drug users . Moreover, HCV-mediated accelerated liver disease is thought to be the main cause of the mortality in HIV-1/HCV co-infected patients . One strategy to address these problems is usually to identify drugs that concurrently diminish contamination and replication of both HCV and HIV-1. Since CypI exhibit antiviral activities against both HIV-1 and HCV individually, we asked in this study whether CypI could inhibit HCV and HIV-1 in the context of co-infection. Indeed, HIV-1 was found to rely on CypA to optimally replicate in human cells and found to be sensitive to CypI such as CsA and non-immunosuppressive CsA derivates [20C25]. Similarly, HCV was found to completely require CypA to replicate both and and that CsA, CsA derivates, sanglifehrins and sanglifehrin derivates block its replication [26C44]. Materials and Methods Drugs The HCV NS5Ai daclatasvir (Daklinza) (Bristol Myers Squibb) and the HIV-1 protease inhibitor nelfinavir were obtained from MedChemexpress (Princeton, NJ 08540, USA). The CypIs ALV and CPI-431-32 were obtained from WuXi AppTec and Ciclofilin Erlotinib mesylate Pharmaceuticals Inc, respectively, whereas CsA was obtained from Sigma-Aldrich, St-Louis, MO, USA). Cells and viruses HIV-1 The HIV-1 target cellsblood-derived CD4+ T-lymphocyteswere isolated as described previously . The Scripps Research Institute Normal Blood Donor Support (TSRI NBDS) provides investigators at TSRI PIK3C3 who have Human Subjects Committee-approved protocols with a source of normal blood for their research. Donors are assured of a controlled clinical setting for their blood to be drawn by licensed phlebotomists, and investigators are assured that this donors whose specimens they obtain through the support have been screened upon entry into the program and.