Melatonin ameliorates endoplasmic reticulum stress in N2a neuroblastoma cell hypoxia-reoxygenation injury by activating the AMPK-Pak2 pathway

Abstract

Endoplasmic reticulum (ER) stress has been identified as a primary factor involved in brain ischemia-reperfusion injury progression. p21-activated kinase 2 (Pak2) is a novel ER function regulator. The aim of our study is to explore the influence of Pak2 on ER stress and determine whether melatonin attenuates ER stress-mediated cell death by modulating Pak2 expression in vitro using N2a cells. The results of our study demonstrated that hypoxia-reoxygenation (HR) injury repressed the levels of Pak2, an effect that was accompanied by activation of ER stress. In addition, decreased Pak2 was associated with oxidative stress, calcium overload, and caspase-12-mediated apoptosis activation in HR-treated N2a cells. Interestingly, melatonin treatment reversed the decreased Pak2 expression under HR stress. Knockdown of Pak2 abolished the protective effects of melatonin on ER stress, oxidative stress, and caspase-12-related N2a cells death. Additionally, we found that Pak2 was regulated by melatonin via the AMPK pathway; inhibition of AMPK prevented melatonin-mediated Pak2 upregulation, a result that was accompanied by an increase in N2a cell death. Altogether, these results identify the AMPK-Pak2 axis as a new signaling pathway responsible for ER stress and N2a cell viability under HR injury. Modulation of the AMPK-Pak2 cascade via supplementation of melatonin might be considered an effective approach to attenuate reperfusion-mediated N2a cell damage via repression of ER stress.

SIRT1 Mediates Melatonin’s Effects on Microglial Activation in Hypoxia: In Vitro and In Vivo Evidence

“…In our work, we first confirmed the expression of melatonin receptor MT1 in both primary and immortalized microglia. MT1 is coupled to Gi and Gq proteins, and its activation inhibits the formation of cyclic AMP, activates AMP-activated protein kinase (AMPK) signaling, and inhibits phospho-CREB and protein-kinase A signaling [55][56][57]. This isoform, in particular, was here chosen because of its known involvement in the neuroprotective actions of melatonin, as from experimental models of newborn hypoxic-ischemic brain injury [17].…”

Meteorin-Like (METRNL) Attenuates Myocardial Ischemia/Reperfusion Injury-Induced Cardiomyocytes Apoptosis by Alleviating Endoplasmic Reticulum Stress via Activation of AMPK-PAK2 Signaling in H9C2 Cells

“…Interestingly, METRNL overexpression played a suppressive role in the expression of aforementioned proteins. Additionally, a previous study reported that PAK2 was identified as a novel regulator of ER function [ 21 ]. Western blot results showed that OGD/R treatment caused decrease of PAK2 expression, which was abolished by METRNL overexpression ( Figure 3B ).…”

“…Meanwhile, AMPK activation has inhibitive impact on ER stress [ 19 ]. Moreover, Xing et al also demonstrated that AMPK-Pak2 axis was identified as a novel signaling cascade responsible for ER stress under hypoxia-reoxygenation injury in neuroblastoma cell [ 21 ]. Consequently, METRNL alleviated MI/R-induced ER stress via activation of AMPK-PAK2 signaling in cardiomyocytes, suggesting METRNL may be expected to represent as a promising target for treatment of myocardial ischemia in the future.…”

VDAC Genes Expression and Regulation in Mammals

“…According to these data, it has been recently reported that the CREB effector of MAPK/ERK signaling pathway triggers the increase of VDAC1 transcription to activate apoptosis induced by H2O2 in cardiac microvascular endothelial cells. Such overexpression can be reestablished at a basal level when melatonin is used as an antioxidant to repair the injury (Xing et al, 2019 ). The experimental observation of VDAC1 transcriptional regulation in stress conditions confirms the importance of this protein in maintaining the correct balance in cell life and death by assuring the functionality of the mitochondria (Fang and Maldonado, 2018 ; Shoshan-Barmatz et al, 2020 ).…”