Research On Anti-aging Activity And Mechanism Of The Endogenous Metabolite Glycerophosphocholine

Aging,a universal physiological phenomenon,is comprehensive manifestation of the decline and disorder in structural homeostasis and functional integrity.Aging serves as a pathogenic factor of various chronic diseases,such as neurodegenerative diseases,cardiovascular diseases,and so on,so it is of great significance to search for anti-aging strategies to improve the quality of life of the elderly.It has been reported that many factors regulate aging.Proteins,nucleic acids and metabolic small molecules in the blood microenvironment are closely related to the aging,while we mainly focus on the regulation of endogenous metabolites on the aging process.In recent years,more and more studies have reported that endogenous metabolites have anti-aging activity.The intermediate product of,α-ketoglutaric acid promotes healthspan and lifespan in C.elegans and mouse models.Furthermore,the supplement of N-acetylglucosamine could extend lifespan in C.elegans,and alleviate the pathology of several distinct neurotoxic disease models.Our study mainly found that the endogenous metabolite glycerophosphocholine(GPC)could promote lifespan and fitness during aging.In this study,we employed an unbiased,systemic metabolomics approach to examine the global metabolic changes during aging.Plasma samples from different ages were collected and non-targeted metabolomics analysis was performed.Among the identified metabolites that changed with age,we found that the plasma GPC level decreased in elderly people as compared to younger ones,indicating its possible role in longevity regulation.To investigate the anti-aging effect of GPC,we first evaluated the effect of GPC on lifespan by using C.elegans.Compared to the control group,GPC treatment had an obvious effect on whole lifespan,mean lifespan,as well as maximum lifespan.As the concentration of GPC increased,the effect of lifespan extension was more obvious.The treatment of nematodes with GPC at a final concentration of 50 m M significantly prolonged the lifespan.The mean lifespan and the maximum lifespan were respectively 26.96 days and 39.18 days,and the lifespan was improved by 22.43%.It is well-known that the motor ability decreases with age.In order to further evaluate the GPC’s effect on anti-aging and mobility,we observed age-related indicators during lifespan assays,including body bending frequency,head swing frequency,pharyngeal pumping rate and the deposition of intestinal lipofuscin.Notably,compared with vehicle,GPC robustly ameliorated age-related phenotypes at the mid-late period of life stage.Lipofuscin is a pigment that fluoresces automatically in the gut of C.elegans.It cannot be eliminated by exocytosis and accumulates in cells in an age-dependent manner,thus reflecting the rate of aging and health status in nematodes.We evaluated the deposition of intestinal lipofuscin to observe the rate of aging.Our findings demonstrated that the lipofuscin fluorescence accumulated with age,while GPC treatment robustly prevented the accumulation of relative fluorescence intensity at the mid-late stage(day 12).These data support our conclusion that GPC significantly delays the ageing process in C.elegans.In addition,we found that GPC could significantly enhance the healthspan without affecting body length and total progenies.These results suggest that GPC could significantly enhance the lifespan and promote fitness without affecting fertility and length in C.elegans.Previous studies have shown that the improvement of stress resistance contributes to lifespan extension in C.elegans.To investigate the potential protective effect of GPC,we conducted oxidative stress and 35℃ heat shock experiments.We found that GPC extended lifespan and improved 6.34% survival rate upon paraquat-induced oxidative stress.After culturing under 35℃ heat shock conditions for 7h,GPC reduced mortality from 83.25% to 47.24%.Under oxidative stress and heat stress,the intracellular ROS can damage cells and organisms,while upregulation of antioxidant genes can increase resistance to stress and thus prolong lifespan.We first monitored the intracellular amount of ROS in C.elegans.Notably,GPC robustly inhibited the ROS accumulation at different life stages,suggesting that GPC has antioxidant activity.ⅡS signaling pathway is a key pathway that plays important roles on lifespan extension and stress response.In order to explore the specific mechanism of GPC,we futher examined the expression of genes in ⅡS signaling pathway.Further experiments demonstrated that GPC up-regulated the expression of daf-16、ins-18、skn-1 和 sek-1,which were downstream gene of ⅡS pathway.Moreover,the expression of sod-3、ctl-1 and ctl-2were up-regulated by GPC.These results show that GPC activates ⅡS signaling pathway.Taken together,using C.elegans as a model organism,we have found that the endogenous metabolite GPC could promote lifespan and fitness during aging.By activating ⅡS signaling pathway,GPC up-regulated the expression of antioxidant genes,thus improving the resistance to stress.Our findings can not only provide new method for the anti-aging research of endogenous metabolites,but also provide new strategies to manipulate the ageing process via the restoration of metabolism homeostasis.