Read S A, Parnell G, Booth D, Douglas M W, George J, Ahlenstiel G
Storr Liver Centre, The Westmead Institute for Medical Research, Westmead Hospital and University of Sydney, Westmead, NSW, Australia.
Centre for Immunology and Allergy Research, The Westmead Institute for Medical Research, University of Sydney, Westmead, NSW, Australia.
J Viral Hepat. 2018 May;25(5):491-501. doi: 10.1111/jvh.12845. Epub 2018 Jan 4.
Metallothioneins (MTs) are small, cysteine-rich proteins characterized by a high affinity for monovalent and divalent cations, such as copper and zinc. Of the four known MT isoforms, only, members of the MT 1 and 2 subfamilies are widely expressed, acting as metal chaperones whose primary role is to mediate intracellular zinc homoeostasis. Metallothioneins are potently induced by heavy metals and other sources of oxidative stress where they facilitate metal binding and detoxification as well as free radical scavenging. Metallothionein expression is well documented in the context of viral infection; however, it remains uncertain whether MTs possess specific antiviral roles or whether induction is merely a consequence of cellular stress. To better understand the role of MTs following hepatitis C virus (HCV) infection, we examined MT expression and localization in vitro and in vivo and used a siRNA knockdown approach to ascertain their antiviral efficacy. We confirmed HCV-driven MT induction in vitro and demonstrated MT accumulation in the nucleus of HCV-infected hepatocytes by immunofluorescence. Using a pan-MT siRNA to knock down all members of the MT1 and MT2 subfamilies, we demonstrate that they are mildly antiviral against the JFH1 strain of HCV in vitro (~1.4 fold increase in viral RNA, P < .05). Furthermore, the antiviral effect of zinc treatment against HCV in vitro was mediated through MT induction (P < .05). Our data suggest a potential benefit of using zinc as a low-cost adjunct to current HCV antiviral therapies and suggest that zinc may facilitate the antiviral role of MTs against other viruses.
金属硫蛋白（MTs）是一类富含半胱氨酸的小蛋白，其特点是对一价和二价阳离子（如铜和锌）具有高亲和力。在已知的四种MT亚型中，只有MT 1和MT 2亚家族的成员广泛表达，作为金属伴侣，其主要作用是介导细胞内锌的稳态。金属硫蛋白可被重金属和其他氧化应激源强烈诱导，在这些情况下，它们有助于金属结合与解毒以及自由基清除。金属硫蛋白的表达在病毒感染的背景下已有充分记录；然而，MTs是否具有特定的抗病毒作用，或者其诱导仅仅是细胞应激的结果，仍不确定。为了更好地理解丙型肝炎病毒（HCV）感染后MTs的作用，我们在体外和体内检测了MT的表达和定位，并使用小干扰RNA（siRNA）敲低方法来确定它们的抗病毒功效。我们在体外证实了HCV驱动的MT诱导，并通过免疫荧光证明了MT在HCV感染的肝细胞细胞核中的积累。使用一种泛MT siRNA敲低MT1和MT2亚家族的所有成员，我们证明它们在体外对HCV的JFH1毒株具有轻度抗病毒作用（病毒RNA增加约1.4倍，P < 0.05）。此外，锌处理在体外对HCV的抗病毒作用是通过MT诱导介导的（P < 0.05）。我们的数据表明，使用锌作为当前HCV抗病毒疗法的低成本辅助药物可能有益，并表明锌可能促进MTs对其他病毒的抗病毒作用。
