Role of miR-148a in Mitigating Hepatic Ischemia-Reperfusion Injury by Repressing the TLR4 Signaling Pathway via Targeting CaMKIIα in Vivo and in Vitro

Abstract

Background/Aims: Hepatic ischemia-reperfusion (I/R) injury, which is mainly induced by inflammation and unstable intracellular ions, is a major negative consequence of surgery that compromises hepatic function. However, the exact mechanisms of liver I/R injury have not been determined. Positive crosstalk with the Ca²⁺/CaMKII pathway is required for complete activation of the TLR4 pathway and inflammation. We previously found that miR-148a, which decreased in abundance with increasing reperfusion time, targeted and repressed the expression of CaMKIIα. In the present study, we examined the role of the miR-148a machinery in I/R-induced Ca²⁺/CaMKII and TLR4 signaling changes, inflammation, and liver dysfunction in vivo and in vitro. Methods: Liver function was evaluated by serum aminotransferase levels and hematoxylin-eosin (HE) staining. Inflammatory factors were detected by enzyme-linked immunosorbent assay. Gene and protein expression were assessed by RT-PCR and western blot. Small interfering RNA was used to silence target gene expression. HE staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling were used to measure hepatic tissue apoptosis. These assays were performed to identify factors upregulated in hepatic I/R injury and downregulated by miR-148a. Results: We manifested that expression of CaMKIIα and phosphorylation of TAK1 and IRF3 were elevated in hypoxia/reoxygenation (H/R)-treated primary Kupffer cells (KCs) and liver tissue of I/R-treated mice, but these effects were attenuated by treatment with miR-148a mimic and were accompanied by the alleviation of liver dysfunction and hepatocellular apoptosis. Luciferase reporter experiments showed that miR148a suppressed luciferase activity by almost 60%. Moreover, knockdown of CaMKIIα in H/R KCs led to significant deficiencies in p-TAK1, P-IRF3, IL-6, and TNF-α, which was consistent with the effects of miR-148a overexpression. Otherwise, the same trend of activation of TAK1 and IRF3 and inflammatory factors in vitro was observed in the siTAK1 + siIRF3 group compared with the siCaMKIIα group. Conclusion: Taken together, we conclude that miR-148a may mitigate hepatic I/R injury by ameliorating TLR4-mediated inflammation via targeting CaMKIIα in vitro and in vivo.

Rbfox-1 contributes to CaMKIIα expression and intracerebral hemorrhage-induced secondary brain injury via blocking micro-RNA-124

“…Previous studies have found that excessive CaMKIIα is associated with a variety of symptoms, including aggravating hepatic ischemia–reperfusion (I/R) damage 10 and participating in the induction of apoptosis in bone cells 33 and neurons. 9 We also found that the overexpression of Rbfox-1 and CaMKIIα was closely related to neuronal death and degeneration, as well as to neurological damage following ICH.…”

“…6–8 A large number of studies have shown that CaMKIIα is involved in and mediates neuronal death in cerebral ischemia and poisoning (fluorosis), which leads to damage of the nervous system. 9–12…”

An Overview of the Role of Calcium/Calmodulin-Dependent Protein Kinase in Cardiorenal Syndrome

“…A previous study suggests that the toll-like receptor (TLR) pathway is linked with the activation of CaMKII in a model of myocardial infarction (Singh et al, 2012). Recently, Wu and collaborators demonstrated that miR-148a attenuates ischemia/reperfusion injury in liver, once CaMKIIα represses the TLR4 signaling pathway in vivo and in vitro, decreasing the production of pro-inflammatory factors (Zheng et al, 2018). Moreover, activation of CaMKII in macrophages is initiated by a significant trigger elevation of intracellular Ca 2+ .…”

Suberoylanilide hydroxamic acid alleviates orthotopic liver transplantation‑induced hepatic ischemia‑reperfusion injury by regulating the AKT/GSK3β/NF‑κB and AKT/mTOR pathways in rat Kupffer cells

“…complex mechanisms are involved in HIRI and studies indicate that Kupffer cells (Kcs), which are liver-resident macrophages, play a crucial role in the inflammatory response in several hepatic diseases (3)(4)(5)(6). Two well-known KC phenotypes, M1 and M2, have different functions in HIRI; M1-polarized Kcs exacerbate IR-induced damage to the liver by producing proinflammatory cytokines such as TNF-α and interleukin (IL)-1β, while anti-inflammatory cytokines, such as IL-10 and TGF-β, are produced by M2-polarized Kcs and protect hepatocytes against IR injury (7)(8)(9). Therefore, increasing the number of M2 cells or reducing the M1 phenotype of Kcs may help to ameliorate HIRI.…”