The Role And Mechanism Of RHBDF1 Signaling Regulated Destruction Of Hippocampal Myelin Structure In Spatial Memory Impairment Induced By Sleep Deprivation

Sleep disorders are important and common problems that affect the life quality of individuals in modern societies.Long-term sleep disorders annoy millions of people and leads to impairment of learning,memory and health,but the mechanism is still unclear.Myelin is a lipid-rich membrane substance surrounded by axons of neurons which is formed by glial cells called oligodendrocytes in central nervous system.It also plays an important role in insulation between axons of neurons and can also improve the conduction of nerve impulses.Myelin basic protein(MBP),myelin-associated glycoprotein(MAG)and etc.are important structural proteins of myelin sheath.RHBDF1 is a catalytically inactive member of the rhomboid family of intramembrane serine proteases and participates in a variety of biological functions such as sleep,development,regeneration,immunity,inflammation,cancer.We aim to investigate effects of spatial memory in different age mice after sleep deprivation(SD),and explore the possible mechanisms related to RHBDF1,so as to provide new ideas for the study of memory disorders caused by sleep deprivation.Objective:To investigate effects of age on spatial learning ability and spatial memory of mice.To investigate effects of spatial memory and myelin in different age mice after sleep deprivation,and the role of RHBDF1 in myelination in mice.And attempt to explore the possible mechanism by which RHBDF1 affects myelin in spatial memory disorders induced by sleep deprivation.Method:Modified multiple platform method was used for depriving sleep.Construction of specific hippocampal region RHBDF1 over mice by injecting adeno-associated virus vector into brain localizer.Morris water maze task was used to evaluate learning ability of mice before SD and memory after SD.During sleep deprivation period weigh was measured.Immunofluorescence technique was used to investigate the expression MBP in Hippocampus.Western blot was used to detect the proteins expression of RHBDF1,ADAM17,p-EGFR,Myelin basic protein(MBP)in brain tissue.Result:1.In SD with different durations(3,5,7 days)experiment.After 3 days SD,there was no obvious change,but the mice had a tendency to sleep.After 5 days SD,the fur of mice was sparse,the color of fur was dim,the reactivity of touch was increased and often with scream.After 7 days SD,the response of the mice was reduced and the death occurs.Compare with control and environmental control groups the weight of SD groups was decreased,the escape latencies were increased,the times of crossing platform and the percentage of time and distance in target quadrant were decreased.The expression of RHBDF1 and MBP protein in the brain of the sleep deprived mice were decreased compared to control and environmental control groups.2.In Morris water maze test on different age mice before SD,the result showed that the latency of place navigation test decreased progressively during the training days in all age groups.The latency of young group was lower than middle age and old groups from the 5th training day.In spatial probe test,the times of crossing platform,the percentage of time and distance in target quadrant were higher than the other two groups.The average speed of the mice in the old group was significantly lower than that in the others.3.During the period of SD,the weight of all SD groups was decreased progressively compare with different age control groups.4.The results of Morris water maze task after SD showed that the escape latency of young mice in the SD group was significantly increased compared with the control group,and the time of crossing platform was significantly reduced.In the middle age mice,the escape latency was increased compared with the control group,but there was no significant difference in the time of crossing platform and the percent of time and distance in target quadrant.In the old mice,the time of crossing platform,the percentage of time and distance in target quadrant were decreased compared with the control.5.The results of MBP immunofluorescence in brain tissue showed that compared with control group of young mice,the expression of MBP in the hippocampal was significantly decreased in the SD group.Compared with the control group of old mice,MBP expression was also decreased in SD group of old mice.6.Western blot results showed that the proteins expression of RHBDF1,MBP,mature-ADAM17 and p-EGFR in the brain of young and old mice with SD were lower than those of the control groups.7.RHBDF1 over inhibits sleep deprivation induced memory loss by maintaining the integrity of myelin sheath.Conclusion:The ability of spatial learning and memory are influenced by age,SD reduced the spatial memory ability of young and aged mice,reduced the expression of RHBDF1,MBP and other proteins in the brain,and damaged the myelin sheath of young and old mice.RHBDF1 overmice in hippocampus could resist the decrease of MBP expression induced by sleep deprivation.Decreased expression of RHBDF1 after SD may affect the expression of MBP through effect activity of ADAM17 and EGFR signaling,which affected myelin integrity after myelin injury.