Targeting A-kinase anchoring protein 12 phosphorylation in hepatic stellate cells regulates liver injury and fibrosis in mouse models.
Targeting A-kinase anchoring protein 12 phosphorylation in hepatic stellate cells regulates liver injury and fibrosis in mouse models.
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作者：
Ramani K;Mavila N;Abeynayake A;Tomasi ML;Wang J;Matsuda M;Seki E
肝星状细胞（HSC）向活化状态的转分化通过释放细胞外基质（ECM）成分而增强肝纤维化，从而扭曲肝脏结构。由于抗纤维化药物的可用性有限，因此可以考虑针对活化的HSC进行药物干预进行治疗。A激酶锚定蛋白12（AKAP 12）是一种支架蛋白，其将蛋白激酶A/C（PKA/PKC）和细胞周期蛋白引导至时空上控制其生物学效应的特定位置。已经表明，AKAP 12的支架功能通过磷酸化而改变。在先前发表的工作中，观察到AKAP 12磷酸化和HSC活化之间的关联。在这项工作中，我们证明了AKAP 12对内质网（ER）驻留胶原蛋白伴侣，热休克蛋白47（HSP 47）的支架活性强烈抑制AKAP 12的位点特异性磷酸化在活化的HSC。AKAP 12磷酸化位点的CRISPR指导的基因编辑恢复了其对HSP 47的支架，抑制了HSP 47的胶原蛋白成熟功能和HSC活化。AKAP 12磷酸编辑显著抑制小鼠的纤维化、ER应激反应、HSC炎症信号传导和肝损伤。我们的总体研究结果表明，AKAP 12磷酸化的促纤维化作用可能是肝纤维化治疗干预的目标。
Trans-differentiation of hepatic stellate cells (HSCs) to activated state potentiates liver fibrosis through release of extracellular matrix (ECM) components, distorting the liver architecture. Since limited antifibrotics are available, pharmacological intervention targeting activated HSCs may be considered for therapy. A-kinase anchoring protein 12 (AKAP12) is a scaffolding protein that directs protein kinases A/C (PKA/PKC) and cyclins to specific locations spatiotemporally controlling their biological effects. It has been shown that AKAP12’s scaffolding functions are altered by phosphorylation. In previously published work, observed an association between AKAP12 phosphorylation and HSC activation. In this work, we demonstrate that AKAP12’s scaffolding activity toward the endoplasmic reticulum (ER)-resident collagen chaperone, heat-shock protein 47 (HSP47) is strongly inhibited by AKAP12’s site-specific phosphorylation in activated HSCs. CRISPR-directed gene editing of AKAP12’s phospho-sites restores its scaffolding toward HSP47, inhibiting HSP47’s collagen maturation functions, and HSC activation. AKAP12 phospho-editing dramatically inhibits fibrosis, ER stress response, HSC inflammatory signaling, and liver injury in mice. Our overall findings suggest a pro-fibrogenic role of AKAP12 phosphorylation that may be targeted for therapeutic intervention in liver fibrosis.