The Effect Of GSK3β Signaling On Ethanol-induced Damage To The Developing Spinal Cord

Alcohol is a widely consumed beverage worldwide,but it also causes damage to organisms at different levels and to varying degrees.Among these damages,alcohol-induced damage in the nervous system has been the focus of research,and existing studies have shown that alcohol exposure during development can lead to multiple levels of brain damage,including smaller brain size,reduced white matter volume,permanent loss of neurons,and a range of changes in synaptogenesis and myelin production.alterations.Alcohol-induced damage to the developing central nervous system has been extensively studied in humans and animals.Several studies using a variety of experimental models,including animal,tissue,and cellular models,have demonstrated that alcohol can cause a range of damage in the brain,such as neuroinflammation and neurodegeneration,and that the effects are more severe in the developing nervous system.In contrast to the large body of research on alcohol-induced brain damage,there is still a large gap in the field of research on alcohol-induced damage in the developing spinal cord.We have previously demonstrated that alcohol induces ER stress in mouse spinal cord neurons via CCR2 signaling,induces glial cell activation,and a number of other injury processes,but the mechanisms by which it ultimately leads to the execution of neuronal apoptosis have not been elucidated in detail.Our results demonstrate that alcohol-induced neuronal apoptosis is distinctly time-sensitive,i.e.,the ability of alcohol to induce apoptosis in spinal dorsal horn neurons diminishes continuously with increasing number of days after birth.At the same time this characteristic difference in temporality is highly consistent with changes in the regulation of phosphorylation of the GSK3β signaling pathway.We demonstrated that neuronal caspase3 activation and apoptosis brought about by alcohol is highly dependent on GSK3β signaling by establishing a mature late gestational equivalent mouse model of alcohol exposure injury as well as by using multiple molecular biology technical approaches on cell line models.The use of GSK3β inhibitors or knockdown of GSK3β can effectively counteract alcohol-induced apoptosis,while overexpression of GSK3β enhances this injury.To more clearly illustrate the rationale for the work of GSK3β in this injury,our further investigated the upstream and downstream targets and regulation of GSK3β in this process.We found that alcohol-induced apoptosis in developing spinal cord dorsal horn neurons relies mainly on the endogenous apoptotic pathway dominated by BAX and its downstream casepase9 rather than exogenous apoptosis.Activated GSK3β can phosphorylate BAX,which translocates BAX to mitochondria,triggering mitochondrial membrane perforation and releasing cytochrome C,which further activates caspase9 and leads to apoptosis.The differential expression of BAX after birth determines the different outcomes directed by the spinal cord at different developmental stages in the face of equivalent stimuli.The present study clarifies the molecular regulatory mechanism of GSK3β signaling imbalance in alcohol-induced apoptosis of spinal cord neurons,with the expectation that it may provide a target for intervention in alcohol and its similar central toxicant damage.