Differential effects of calcineurin inhibitors, tacrolimus and cyclosporin a, on interferon-induced antiviral protein in human hepatocyte cells

Abstract

The premise of our study is that selective inhibition of interferon (IFN) by calcineurin inhibitors contribute to the increased severity of hepatitis C virus (HCV) posttransplantation. Therefore, we examined the influence of calcineurin inhibitors in the human hepatocyte cell line on IFN-␣-induced phosphorylation of Janus kinase (Jak) and signal transducers and activators of transcription (STAT), nuclear translocation of IFN-stimulated gene factor 3 (ISGF-3), IFN-stimulated regulatory element (ISRE)-contained promoter activity, and the expressions of antiviral proteins. Tacrolimus (Tac), but not cyclosporin A (CyA), had an inhibitory effect on IFN-␣-induced double-stranded ribonucleic acid (RNA)-dependent protein kinase (PKR) in a dose-dependent manner. STAT-1 also acted in a similar fashion to PKR. IFN-␣ combined with Tac attenuated the ISREcontaining promoter gene activity as compared with IFN-␣ alone. In contrast, its expression in pretreated CyA was slightly attenuated. In pretreated Tac, but not CyA, the levels of IFN-␣-induced tyrosine phosphorylated STAT-1 and -2 were clearly lower than those induced by IFN-␣ alone. Tac and CyA did not decrease the IFN-␣-induced JAK-1 phosphorylation. The nuclear translocation rate of tyrosine phosphorylated STAT-1 was inhibited by pretreatment of both Tac and CyA by western blotting and immunohistochemistry. In an HCV replicon system, pretreated Tac diminished the replication inhibitory effect of IFN-␣. In this study, we show that calcineurin inhibitors, especially Tac, are the negative regulators of IFN signaling in the hepatocyte; the greatest cause of such inhibition is the phosphorylation disturbance of STAT-1, next to inhibition of the nuclear translocation of STAT-1. In conclusion, disturbance of tyrosine phosphorylation of STAT-1 resulted in diminished ISREcontaining promoter activity and a decline in antiviral protein expression. Moreover, the replication of HCV was activated. This phenomenon is detrimental to IFN therapy after liver transplantation, and the selection of calcineurin inhibitors may warrant further discussion depending on the transplant situation. Liver Transpl 14:292-298, 2008. © 2008 AASLD. Received March 8, 2007 accepted August 17, 2007. See Editorial on Page 265Hepatitis C virus (HCV) infection is widespread worldwide. A major problem of chronic HCV infection is hepatocellular carcinoma. Currently, liver transplantation for HCV-related liver disease is an option worldwide. Recently, it has been demonstrated that the prognosis for liver transplantation patients with HCV-related disease deteriorates with time, 2 resulting in a poorer out-

Hepatitis C virus viral kinetics during α-2a or α-2b pegylated interferon plus ribavirin therapy in liver transplant recipients with different immunosuppression regimes

“…The role of Tac and CsA in peg-IFN-␣ treatment in LT patients is controversial. 9,[44][45][46][47][48][49][50] More than half of our CsA patients showed delayed monophasic viral load kinetics, which did not preclude SVR, as seen in some HCV/HIV coinfected patients with delayed monophasic declines. 27,33 Our results are surprising in the sense that a faster decline may be expected under CsA due to its suppressive effect on HCV replication demonstrated in cell culture, animal models, or in clinical trials.…”

Review on immunosuppression in liver transplantation

“…There is evidence of in vitro anti replicative effect of cyclosporine on HCV RNA [85,86] . Cyclosporine has also been reported to show less interferrence with the anti-viral effect of interferon-α in HCV infected human hepatocytes when compared with tacrolimus [87] . The results of studies comparing the effect of cyclosporine and tacrolimus on post transplant HCV recurrence, fibrosis progression and sustained virologic response after treatment are conflicting [88] .…”

Functional expression of double‐stranded RNA‐dependent protein kinase in rat intestinal epithelial cells

“…Although the PKR expression was upregulated after postconfluent cultures, hydrocortisone-treatment suppressed the increment of PKR expression and ALP activity in the treated cells. Another type of immune suppressive reagent, calcineurin inhibitor Tacrolimus, also had an inhibitory effect on INF-a-induced PKR expression [Hirano et al, 2008]. These modulations may be partially mediated by STAT-1 protein.…”