Hydrogen exerts neuroprotective effects on OGD/R damaged neurons in rat hippocampal by protecting mitochondrial function via regulating mitophagy mediated by PINK1/Parkin signaling pathway

Abstract

Cerebral ischemia/reperfusion injury (IRI) is a serious complication during the treatment of stroke patients with very few effective clinical treatment. Hydrogen (H2) can protect mitochondria function and have favorable therapeutic effects on cerebral IRI. Mitophagy plays an important role in eliminating damaged or dysfunctional mitochondria and maintaining mitochondria homeostasis. However, whether the protection of H2 on cerebral IRI is via regulating mitophagy is still unknown. In this study, OGD/R damaged hippocampal neurons were used to mimic cerebral IRI in vivo and we detected the effect of H2, Rap (autophagy activator) and 3-MA (autophagy inhibitor) on OGD/R neurons. The results of MTT indicated that H2 and RAP could increase cell viability after OGD/R treatment, while 3-MA further aggravated injury and inhibited the protection of H2 and RAP. Furthermore, the intracellular ROS and apoptosis ratio were determined, the results showed that ROS and apoptosis level significantly increased after OGD/R, H2 and RAP effectively restrained the increment of ROS level and apoptosis ratio but their protective effect can be weakened by 3-MA. Mitochondrial membrane potential (MMP) and mitophagy level were also determined, the data showed that H2 and RAP protected against the loss of MPP and increased the co-localization of mitochondria with GFP-LC3 while 3-MA exerted antagonistic effect. At last, the mitophagy-related factors LC3, PINK1 and Parkin expression were detected and analyzed. We found that the expression of LC3 was increased after OGD/R which can be further enhanced by H2 and RAP treatment, but treatment with 3-MA was opposite. The result revealed H2 and RAP could activate mitophagy while 3-MA inhibit mitophagy. In addition, the study found H2 and RAP could significantly induce the expression of PINK1 and Parkin in OGD/R neurons which was inhibited by 3-MA. Taken together, our findings demonstrated H2 had a neuroprotective effect on OGD/R damaged neurons by protecting mitochondrial function and the potential protection mechanism may closely related to enhancement of mitophagy mediated by PINK1/Parkin signaling pathway.

LncRNA SNHG14 promotes OGD/R-induced neuron injury by inducing excessive mitophagy via miR-182-5p/BINP3 axis in HT22 mouse hippocampal neuronal cells

“…f The expression of BNIP3, caspase-3, cleaved-caspase-3, caspase-9 and cleaved-caspase-9 in the modified HT22 cells was examined by WB. (*P < 0.05, **P < 0.01, versus mimic NC + Vector or Vector + si-Ctrl; # P < 0.05, ## P < 0.01, versus Vector + miR-182-5p mimic Vector + si-BNIP3) mitophagy has a crucial role in various diseases, such as CI/R injury [20], Parkinson's disease and septic acute kidney injury [21,22]. However, SNHG14 overexpression or knockdown had no effect on the expression of PINK1 and Parkin, suggesting that SNHG14 can not regulate mitophagy by activating PINK1/Parkin signaling pathway.…”

HIF-1α-BNIP3-mediated mitophagy in tubular cells protects against renal ischemia/reperfusion injury

“…There are accumulating data showing that mitophagy plays an important role in eliminating damaged or dysfunctional mitochondria and maintaining mitochondria homeostasis [ 39 ]. Mitochondria contain less cytochrome c and more pro-apoptotic protein Bax expression; it tends to swell, break, and have a lower membrane potential [ 40 ].…”

“…In cerebral and cardiac ischemia injury, however, autophagy can be protective or destructive [ 20 , 21 ]._ENREF_17 For example, it has been reported that hydrogen, heat shock protein B8 (HSPB8) exert neuroprotective effects by protecting mitochondrial function via enhanced mitophagy in oxygen-glucose deprivation/reoxygenation-induced neuron damage in rat hippocampal [ 39 , 54 ]._ENREF_37 In contrast, it has been reported that knockout of programmed cell death 5 (PCD5) has a protective role in middle cerebral artery occlusion model by promoting apoptosis and autophagy through the activation of HIF-1α-BNIP3 signaling pathway [ 55 ]. This inconsistency is similar with cardiomyocyte.…”

Specific cyprinid HIF isoforms contribute to cellular mitochondrial regulation

“…It has been demonstrated that the increased of ROS production can inhibit prolyl hydroxylase enzyme (PHD) activity, and prevent the degradation and enhance the stability of HIF-1 44 . However, excessive ROS may related to the cellular oxidative damage, such as mitochondrial dysfunction and mitophagy 45 . Hif-1aa improved ROS production and concomitant increase of mitochondrial membrane potential, suggesting that Hif-1aa maintains hyperpolarization of the mitochondrial membrane potential.…”