■受体相互作用的丝氨酸/苏氨酸蛋白激酶3(RIPK3)是触发坏死性细胞死亡的主要参与者。然而,巨噬细胞RIPK3是否可以调节NOD1依赖性炎症和钙调磷酸酶/瞬时受体电位阳离子通道亚家族M成员7(TRPM7)在氧化应激诱导的肝脏炎症损伤中诱导的肝细胞死亡仍不清楚.
■肝缺血再灌注(IR)损伤的小鼠模型,原代肝细胞,和骨髓来源的巨噬细胞用于骨髓特异性RIPK3敲除(RIPK3M-KO)和RIPK3高(RIPK3FL/FL)小鼠。
■RIPK3M-KO减少了IR应激诱导的肝损伤,降低了血清丙氨酸转氨酶/天冬氨酸转氨酶水平,巨噬细胞/中性粒细胞浸润,和促炎介质与RIPK3FL/FL对照相比。IR应激激活的RIPK3,需要肌醇的跨膜激酶/核糖核酸内切酶1α(IRE1α),x盒结合蛋白1(XBP1),含核苷酸结合寡聚化结构域的蛋白1(NOD1),NF-κB,叉头箱O1(Foxo1),钙调磷酸酶A,和TRPM7在缺血性肝脏。相反,RIPK3M-KO抑制IRE1α,XBP1,NOD1,钙调磷酸酶A,和TRPM7激活,血清肿瘤坏死因子α(TNF-α)水平降低。此外,Foxo1M-KO减轻IR诱导的肝损伤,降低NOD1和TRPM7表达。有趣的是,染色质免疫沉淀与大规模平行测序相结合显示,巨噬细胞Foxo1与XBP1共定位并激活了其靶基因Zc3h15(含锌指CCCH结构域的蛋白15)。激活巨噬细胞XBP1可增强Zc3h15、NOD1和NF-κB活性。然而,巨噬细胞Zc3h15的破坏抑制NOD1和肝细胞钙调磷酸酶/TRPM7的激活,巨噬细胞/肝细胞共培养后,活性氧的产生和乳酸脱氢酶的释放减少。此外,RIPK3M-KO小鼠中表达Zc3h15的巨噬细胞的过继转移增加了IR引发的肝脏炎症和细胞死亡。
■巨噬细胞RIPK3激活IR应激肝脏中的IRE1α-XBP1通路和Foxo1信号传导。XBP1-Foxo1相互作用对于调节靶基因Zc3h15功能至关重要,这对于控制NOD1和钙调磷酸酶介导的TRPM7激活至关重要。XBP1在调节NOD1驱动的肝脏炎症和钙调磷酸酶/TRPM7诱导的细胞死亡中充当Foxo1的转录共激活因子。我们的发现强调了巨噬细胞RIPK3在应激诱导的肝脏炎症和细胞死亡中的新作用,暗示肝脏炎症性疾病的潜在治疗靶点。
■巨噬细胞RIPK3通过触发XBP1-Foxo1轴及其靶基因Zc3h15促进NOD1依赖性炎症和钙调磷酸酶/TRPM7诱导的细胞死亡级联反应,这对于激活NOD1和钙调磷酸酶/TRPM7功能至关重要,提示潜在的治疗靶点在应激诱导的肝脏炎症损伤。
UNASSIGNED: Receptor-interacting serine/threonine-protein kinase 3 (RIPK3) is a central player in triggering necroptotic cell death. However, whether macrophage RIPK3 may regulate NOD1-dependent inflammation and calcineurin/transient receptor potential cation channel subfamily M member 7 (TRPM7)-induced hepatocyte death in oxidative stress-induced liver inflammatory injury remains elusive.
UNASSIGNED: A mouse model of hepatic ischaemia-reperfusion (IR) injury, the primary hepatocytes, and bone marrow-derived macrophages were used in the myeloid-specific RIPK3 knockout (RIPK3M-KO) and RIPK3-proficient (RIPK3FL/FL) mice.
UNASSIGNED: RIPK3M-KO diminished IR stress-induced liver damage with reduced serum alanine aminotransferase/aspartate aminotransferase levels, macrophage/neutrophil infiltration, and pro-inflammatory mediators compared with the RIPK3FL/FL controls. IR stress activated RIPK3, inositol-requiring transmembrane kinase/endoribonuclease 1α (
IRE1α), x-box binding protein 1 (XBP1), nucleotide-binding oligomerisation domain-containing protein 1 (NOD1), NF-κB, forkhead box O1 (Foxo1), calcineurin A, and TRPM7 in ischaemic livers. Conversely, RIPK3M-KO depressed
IRE1α, XBP1, NOD1, calcineurin A, and TRPM7 activation with reduced serum tumour necrosis factor α (TNF-α) levels. Moreover, Foxo1M-KO alleviated IR-induced liver injury with reduced NOD1 and TRPM7 expression. Interestingly, chromatin immunoprecipitation coupled with massively parallel sequencing revealed that macrophage Foxo1 colocalised with XBP1 and activated its target gene Zc3h15 (zinc finger CCCH domain-containing protein 15). Activating macrophage XBP1 enhanced Zc3h15, NOD1, and NF-κB activity. However, disruption of macrophage Zc3h15 inhibited NOD1 and hepatocyte calcineurin/TRPM7 activation, with reduced reactive oxygen species production and lactate dehydrogenase release after macrophage/hepatocyte coculture. Furthermore, adoptive transfer of Zc3h15-expressing macrophages in RIPK3M-KO mice augmented IR-triggered liver inflammation and cell death.
UNASSIGNED: Macrophage RIPK3 activates the
IRE1α-XBP1 pathway and Foxo1 signalling in IR-stress livers. The XBP1-Foxo1 interaction is essential for modulating target gene Zc3h15 function, which is crucial for the control of NOD1 and calcineurin-mediated TRPM7 activation. XBP1 functions as a transcriptional coactivator of Foxo1 in regulating NOD1-driven liver inflammation and calcineurin/TRPM7-induced cell death. Our findings underscore a novel role of macrophage RIPK3 in stress-induced liver inflammation and cell death, implying the potential therapeutic targets in liver inflammatory diseases.
UNASSIGNED: Macrophage RIPK3 promotes NOD1-dependent inflammation and calcineurin/TRPM7-induced cell death cascade by triggering the XBP1-Foxo1 axis and its target gene Zc3h15, which is crucial for activating NOD1 and calcineurin/TRPM7 function, implying the potential therapeutic targets in stress-induced liver inflammatory injury.