Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA; Liver Transplantation Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China.
Liver Transplantation Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China.
J Hepatol. 2018 Jul;69(1):99-109. doi: 10.1016/j.jhep.2018.01.036. Epub 2018 Feb 13.
BACKGROUND & AIMS: Glycogen synthase kinase 3β (Gsk3β [Gsk3b]) is a ubiquitously expressed kinase with distinctive functions in different types of cells. Although its roles in regulating innate immune activation and ischaemia and reperfusion injuries (IRIs) have been well documented, the underlying mechanisms remain ambiguous, in part because of the lack of cell-specific tools in vivo.
We created a myeloid-specific Gsk3b knockout (KO) strain to study the function of Gsk3β in macrophages in a murine liver partial warm ischaemia model.
Compared with controls, myeloid Gsk3b KO mice were protected from IRI, with diminished proinflammatory but enhanced anti-inflammatory immune responses in livers. In bone marrow-derived macrophages, Gsk3β deficiency resulted in an early reduction of Tnf gene transcription but sustained increase of Il10 gene transcription on Toll-like receptor 4 stimulation in vitro. These effects were associated with enhanced AMP-activated protein kinase (AMPK) activation, which led to an accelerated and higher level of induction of the novel innate immune negative regulator small heterodimer partner (SHP [Nr0b2]). The regulatory function of Gsk3β on AMPK activation and SHP induction was confirmed in wild-type bone marrow-derived macrophages with a Gsk3 inhibitor. Furthermore, we found that this immune regulatory mechanism was independent of Gsk3β Ser9 phosphorylation and the phosphoinositide 3-kinase-Akt signalling pathway. In vivo, myeloid Gsk3β deficiency facilitated SHP upregulation by ischaemia-reperfusion in liver macrophages. Treatment of Gsk3b KO mice with either AMPK inhibitor or SHP small interfering RNA before the onset of liver ischaemia restored liver proinflammatory immune activation and IRI in these otherwise protected hosts. Additionally, pharmacological activation of AMPK protected wild-type mice from liver IRI, with reduced proinflammatory immune activation. Inhibition of the AMPK-SHP pathway by liver ischaemia was demonstrated in tumour resection patients.
Gsk3β promotes innate proinflammatory immune activation by restraining AMPK activation.
Glycogen synthase kinase 3β promotes macrophage inflammatory activation by inhibiting the immune regulatory signalling of AMP-activated protein kinase and the induction of small heterodimer partner. Therefore, therapeutic targeting of glycogen synthase kinase 3β enhances innate immune regulation and protects liver from ischaemia and reperfusion injury.
糖原合酶激酶 3β（Gsk3β[Gsk3b]）是一种普遍表达的激酶，在不同类型的细胞中具有独特的功能。尽管其在调节固有免疫激活和缺血再灌注损伤（IRIs）中的作用已有充分的文献记载，但潜在机制仍不明确，部分原因是体内缺乏细胞特异性工具。
我们创建了髓系特异性 Gsk3b 敲除（KO）品系，以在小鼠肝脏部分热缺血模型中研究 Gsk3β 在巨噬细胞中的功能。
与对照组相比，髓系 Gsk3b KO 小鼠对 IRI 具有保护作用，肝脏中促炎但增强抗炎免疫反应减少。在骨髓来源的巨噬细胞中，Gsk3β 缺乏导致 TNF 基因转录早期减少，但 Toll 样受体 4 刺激时 Il10 基因转录持续增加。这些效应与 AMP 激活蛋白激酶（AMPK）的激活增强有关，这导致新型固有免疫负调节因子小异二聚体伴侣（SHP[Nr0b2]）的诱导加速和水平升高。用 Gsk3 抑制剂在野生型骨髓来源的巨噬细胞中证实了 Gsk3β 对 AMPK 激活和 SHP 诱导的调节作用。此外，我们发现这种免疫调节机制独立于 Gsk3β Ser9 磷酸化和磷脂酰肌醇 3-激酶-Akt 信号通路。在体内，髓系 Gsk3β 缺乏通过缺血再灌注促进肝脏巨噬细胞中 SHP 的上调。在肝脏缺血发生之前，用 AMPK 抑制剂或 SHP 小干扰 RNA 处理 Gsk3b KO 小鼠可恢复这些受保护宿主的肝脏促炎免疫激活和 IRI。此外，野生型小鼠的 AMPK 药理学激活可减轻肝脏 IRI，减少促炎免疫激活。在肿瘤切除术患者中证明了 AMPK-SHP 途径的缺血抑制作用。
Gsk3β 通过抑制 AMPK 激活促进固有促炎免疫激活。
Gsk3β 通过抑制 AMP 激活蛋白激酶的免疫调节信号和小异二聚体伴侣的诱导来促进巨噬细胞的炎症激活。因此，糖原合酶激酶 3β 的治疗靶向增强固有免疫调节并保护肝脏免受缺血再灌注损伤。
