Inhibition of excessive mitophagy by N-acetyl-L-tryptophan confers hepatoprotection against Ischemia-Reperfusion injury in rats

Abstract

In order to investigate the mechnism of hepatoprotective of N-acetyl-L-tryptophan (L-NAT) against ischemia-reperfusion (I/R) injury, the effects of L-NAT were investigated in hepatic ischemia-reperfusion injury (HIRI) models both in vitro and in vivo, which were made by BRL cells and Sprague-Dawley (SD) rats, respectively. The cell viability of hepatocyte was assessed by cell counting kit-8 (CCK-8) staining. The activation of autophagy was detected by electron microscopy (EM), quantitative real-time PCR (qRT-PCR), Western blotting and immunofluorescence. The activation of mitophagy was determined by the change of autophagy related protein, change of mitochondrial structure and function, co-location of autophagy protein and MitoTracker. Results showed that the morphological structures of hepatocytes were changed significantly after HIRI, and the cell viability of hydrogen peroxide (H2O2)-induced BRL cells was decreased. Autophagy markers Beclin1, microtubule associated protein 1 light chain 3-II (LC3-II) and autophagy related protein-7 (ATG-7) were highly expressed and the expression of SQSTM1 (P62) was decreased after HIRI, which suggested that autophagy of hepatocytes was activated after I/R. The reduction of ATP, mitochondrial DNA (mtDNA) and the mitochondrial transmembrane potential (ΔΨm) after H2O2-induced revealed that function of mitochondrial had also undergone significant changes. The increased expression of autophagy protein, destructure of mitochondria and mitochondrial dysfunction, the increased co-location of Beclin1 and MitoTracker induced by H2O2 implied the excessive mitophagy. The expression of the autophagy protein was increased by 3-Methyladenine (3-MA), providing another piece of evidence. Importantly, all changes were restored by L-NAT pretreament. In conclusion, the present findings demonstrate that excessive mitophagy involved in the process of HIRI and L-NAT may protect hepatocytes against HIRI by inhibiting activation of mitophagy and improving the structure and function of mitochondria.

Long non-coding RNA HCG11 silencing protects against cerebral ischemia/reperfusion injury through microRNA miR-381-3p to regulate tumour protein p53

“…Previous studies have confirmed that CI/R injury can include the secretion of neuroinflammatory and excessive production of oxidative stress, thereby aggravating brain injury [18]. The results showed that ROS and MDA levels in MCAO model rats were increased, and the levels of SOD were decreased (p < 0.001, Fig.…”

N-acetyl-L-tryptophan attenuates hepatic ischemia-reperfusion injury via regulating TLR4/NLRP3 signaling pathway in rats

“…Previous results of our laboratory showed that SP aggravated the oxidative damage of NSC-34 cell and L-NAT could not only prevent the secretion of SP, but also inhibit the activation of Caspase-1 and IL-1β, indicating that L-NAT may be the effective agent in the treatment of ALS (Sirianni et al, 2015). Used partial HIRI animal models and H 2 O 2 -induced BRL cell oxidative injury models, we not only observed the protective effect of L-NAT on HIRI (Wang et al, 2019); (Li et al, 2020a), but also demonstrated its protection on the striatum and intestinal injury induced by HIRI (Wang et al, 2017;Zhao et al, 2016). At present, the molecular mechanisms underlying the hepatic-protection of L-NAT remains unknown.…”

“…Rats were allowed free access to water, while fasted 12 h before surgery. According to previous studies, rats in the I/R + L-NAT group administrated L-NAT at a dose of 10 mg/kg through intraperitoneal injection, while those in the sham and I/R groups were given the same volume of saline 30 min before surgery ( Li et al, 2020a ).…”

Cephalotaxine Inhibits the Survival of Leukemia Cells by Activating Mitochondrial Apoptosis Pathway and Inhibiting Autophagy Flow

“…Therefore, the effect of CET on autophagy was further investigated. Mitophagy is a major pathway for the elimination of damaged mitochondria [ 20 ]. Therefore, we speculated that CET might affect the mitophagy or autophagy.…”