The Role Of Small Ubiquitin-like Modifier-specific Protease 3 In Early Brain Injury After Experimental Subarachnoid Hemorrhage

Subarachnoid hemorrhage(SAH),especially aneurysm subarachnoid hemorrhage(aSAH)is a fatal disease with high morbidity and disability ratio of survivors.In most country,aSAH contributes to 20%of strokes that is the third reason of death.In spite of SAH presents low mortality,it usually relates to early age onset and terrific outcome in lots of death cases.Current researches proved that the major reasons of poor outcome results are early brain injury(EBI)and cerebral vasospasm(CVS).CVS was considered for decades to be the unique and paramount factor of poor outcome following subarachnoid hemorrhage.However,the multi-center CONSCIOUS trials demonstrated that there is not any effect on long-term outcome following significant reductions in angiographic vasospasm.And reviews from published studies showed that delayed CVS is not a sufficient condition of poor outcome and there was vast probability that EBI is another factor influencing outcome.Therefore,more and more researches convert from CVS to EBI.Small ubiquitin-like modifier(SUMO)is covalently linked to a variety of proteins and is deconjugated by SUMO-specific proteases.It modifies protein at post-translation and functions in various kinds of cell signaling pathways.SENPs is an isopeptidase in guaranteeing SUMO homeostasis between modified protein substrates(SUMOylation)and not modified protein substrates(deSUMOylation).Disrupting the homeostasis contributes to cancer development and progression.SUMOylation is also important in the CNS where the processes influencing differentiation,growth,targeting and communication between neurons which are highly complex and tightly regulated.General increasing of SUMO-2/3 conjugation is a neuroprotective response to severe stress.Extra SENP3 could reverse this neuroprotection in a ischemia model.SNEP3 is prevented from proteasomal degradation related ubiquitin when calculated ROS stimulate cells.Few studies examining SENP3 in the central nerve system in indicate that this enzyme is related to apoptosis which is one of the most important mechanisms of EBI following SAH.In ischemia,depletion of SENP3 prolongs Drp1 SUMOylation,which suppresses Drp1-mediated cytochrome c release and caspase-mediated neurons death in an vitro model.In spinal cord injury(SCI),SENP3 is upregulation and Implicates for neuronal apoptosis.There is no study on SENP3 in SAH.Therefore,we designed this study to disscuss the role of SENP3 related to oxidative stress in early brain injury after experimental SAH.Experimental SAH was Imitated by injection with 0.3ml nonheparinized autoblood into the prechiasmatic cistern.lentivirous were administrated into rats’ left lateral ventricle to down-regulate SENP3.MDA levels,SOD activities,and GSH contents was detected to evaluate oxidative stress level.SENP3 expression is surveyed by western blot analysis,real-time polymerase chain reaction(PCR),immunohistochemistry and immunofluorescence.cleaved caspase 3 were detected by western blot,apoptosis was observed by TUNEL staining.Our results demonstrated that SAH induced a significant up-regulation of SENP3 protein expression which peaked at 24h;however,mRNA expressions of SENP3 were not changed.There is highly positive relationship between cleavage caspase3 and SENP3 in protein level.Immunofluorescence results showed expression of SENP3 was increased in neurons,while neither in astrocytes nor microglia.high oxidative stress level following SAH induced rising of SENP3.And Inhibition of SENP3 by lentivirus induces suppression of apoptosis in experimental subarachnoid hemorrhage in rats.Because of these results,we concluded that SAH caused an obvious up-regulation of SENP3 protein expression in brain,especially in neurons.lt is a cellular proced ure after transcription and when SENP3 accumulated by high oxidative stress,caspase 3 activated subsequently.And it leads to more severe apoptosis than normal.