Regulation of Liver Fibrosis by Pyruvate Kinase M2 (PKM2)

我们已经确定了PKM2在HSC生物学和肝脏中的一个重要的和以前未知的作用

We have identified an important and previously unknown role for PKM2 in HSC biology and liver fibrosis. This work will give us a full mechanistic understanding of how PKM2 regulates hepatic stellate (HSC) metabolism and activation, and test PKM2-binding new chemical entities for anti-fibrotic activity. HSC are central to the development of liver fibrosis. There is extensive information on the many transcriptional changes associated with HSC activation but how these changes are initiated and regulated is still not well understood. From the work in the current Merit award we have identified a novel role for pyruvate kinase M2 (PKM2) in nuclear regulation of pro-glycolytic, pro-inflammatory and pro-reactive oxygen species genes in liver macrophages (LM). HSC, upon activation, are faced with the same organizational challenges as macrophages and other cells which transition from a quiescent to a highly proliferative and anabolic state. Hypothesis: Pyruvate Kinase M2 (PKM2) is a key regulator of liver fibrosis. Aim 1: Identify the regulatory mechanisms of PKM2 mediated HSC activation. a) Identify the TGF-β1 induced post- translational modifications (PTM) in PKM2 required for PKM2 nuclear translocation. Test the ability of Erk 1/2 MAP kinases to phosphorylate key sites of PKM2 and use site specific Flag mutants of PKM2 to identify which mutations result in loss of nuclear localization. b) Identify the nuclear mechanism of PKM2 mediated transactivation of HSC activation and fibrotic response. Aim 2: Identify the HSC intrinsic and extrinsic roles of PKM2 in liver fibrosis. a) Identify the HSC intrinsic roles of PKM2 in liver fibrosis: Determine the role of PKM2 in regulating HSC metabolic adaptation and downstream events. b) Identify the role of hepatocyte PKM2 in liver fibrosis: Determine the role of hepatocyte PKM2 in the production by hepatocytes of TGF-β1 and other cytokines that regulate the TGF-β1 pathway. Aim 3: Test the in vivo efficacy of novel PKM2 inhbitors for anti-fibrotic activity. We will test the ability of TEPP-45, and additional novel PKM2 binders, in preventing and reversing liver fibrosis. The current work will give us a full mechanistic understanding of how PKM2 in different liver cell populations regulates HSC activation, and liver fibrosis.