miR‐210 Participates in Hepatic Ischemia Reperfusion Injury by Forming a Negative Feedback Loop With SMAD4

Abstract

Background and Aims Hepatic ischemia‐reperfusion (IR) injury is a major complication of liver transplantation, resection, and hemorrhagic shock. Hypoxia is a key pathological event associated with IR injury. MicroRNA‐210 (miR‐210) has been characterized as a micromanager of hypoxia pathway. However, its function and mechanism in hepatic IR injury is unknown. Approach and Results In this study, we found miR‐210 was induced in liver tissues from patients subjected to IR‐related surgeries. In a murine model of hepatic IR, the level of miR‐210 was increased in hepatocytes but not in nonparenchymal cells. miR‐210 deficiency remarkably alleviated liver injury, cell inflammatory responses, and cell death in a mouse hepatic IR model. In vitro, inhibition of miR‐210 decreased hypoxia/reoxygenation (HR)–induced cell apoptosis of primary hepatocytes and LO2 cells, whereas overexpression of miR‐210 increased cells apoptosis during HR. Mechanistically, miR‐210 directly suppressed mothers against decapentaplegic homolog 4 (SMAD4) expression under normoxia and hypoxia condition by directly binding to the 3′ UTR of SMAD4. The pro‐apoptotic effect of miR‐210 was alleviated by SMAD4, whereas short hairpin SMAD4 abrogated the anti‐apoptotic role of miR‐210 inhibition in primary hepatocytes. Further studies demonstrated that hypoxia‐induced SMAD4 transported into nucleus, in which SMAD4 directly bound to the promoter of miR‐210 and transcriptionally induced miR‐210, thus forming a negative feedback loop with miR‐210. Conclusions Our study implicates a crucial role of miR‐210‐SMAD4 interaction in hepatic IR‐induced cell death and provides a promising therapeutic approach for liver IR injury.

Identification of hub genes and transcription factor-miRNA-mRNA pathways in mice and human renal ischemia-reperfusion injury

“…In addition, we also found four regulatory loops, including Fosl2-miR-155-Fosl2, Fosl2-miR-146a-Fosl2, Cebpb-miR-155-Cebpb and Mafk-miR-25-Mafk. Regulatory loop has been reported in liver ischemia-reperfusion injury ( Pan et al, 2020 ). Our results showed that transcription factors bind to the promoter of miRNA and induce miRNA express, so as to form a negative feedback loop with TF and maintain the stability of their expression level.…”

MicroRNAs: Novel Targets in Hepatic Ischemia–Reperfusion Injury

“…SMAD4 is suppressed when miR-210 is overexpressed. miR-210 knockout mice showed higher expression of SMAD4 and lower inflammatory markers and apoptosis [43]. Upon IRI, the miR-210 knockout mice had significantly lower ALT and AST levels in addition to lower TNF-α, IL-6, and IL-1β when compared to the wild-type mice [43].…”

“…miRNA-210 miR-210 was upregulated, leading to an increase in hepatocyte apoptosis during hepatic IRI [43]. miR-210 targets SMAD4 in the hypoxia pathway [43]. SMAD4 is suppressed when miR-210 is overexpressed.…”

“…miR-210 knockout mice showed higher expression of SMAD4 and lower inflammatory markers and apoptosis [43]. Upon IRI, the miR-210 knockout mice had significantly lower ALT and AST levels in addition to lower TNF-α, IL-6, and IL-1β when compared to the wild-type mice [43]. Inhibition of miR-210 is a potential strategy for decreasing cell apoptosis and inflammatory responses during hepatic IRI.…”

“…The establishment of large clinical cohorts is necessary to investigate the presence or absence of specific miRNAs before and after transplantation. Exaggerates hepatic IRI when upregulated [30,31,33,58] miR-450b Upregulated CRYAB Exaggerates hepatic IRI upon upregulation [34] miR-155 Upregulated SOCS1 Exaggerates hepatic IRI when upregulated [35][36][37] miR-191 Upregulated ZONAB Exaggerates hepatic IRI when upregulated [38,39] miR-370 Upregulated TβRII Exaggerates hepatic IRI when upregulated [40,41] miR-210 Upregulated SMAD4 Exaggerates hepatic IRI when upregulated [43] miR-34 Upregulated SIRT1 Exaggerates hepatic IRI when upregulated [44,45] miR-297 Upregulated SIRT3 Exaggerates hepatic IRI when upregulated [56] miR-497-5p Upregulated MED1/TIMP-2 Exaggerates hepatic IRI when upregulated [46] miR-128-3p Upregulated Rnd3 Exaggerates hepatic IRI when upregulated [47] miR-146a Downregulated TRAF6 and IRAK1…”