Effect And Mechanism Of Handelin On Delaying Aging And Sarcopenia

Aging,basic feature of life,progressive physiological changes in an organism that is inevitable,or a decline of biological functions and of the organism’s ability to adapt to metabolic stress,accompanied by various age-related diseases,which bring great inconvenience to the life of the elderly and great health and economic challenges to the society.Sarcopenia regards as an invisible killer that impacts millions of older adults.Its prevalence reached to 67.1% in people over 80 years old which is a systemic skeletal muscle disease characterized by loss of muscle mass and function,causing dysfunction and increasing the risk of falls,disability and death in the elderly.Currently,resistance training and adequate protein and energy intake are the key strategies for the management of sarcopenia.Drug therapy such as hormones,myostatin inhibitors and natural products such as resveratrol and quercetin may be necessary for sarcopenia in some cases.These natural products mainly exert their effects through anti-inflammatory and antioxidant activities.Previous study found that extracts of wild chrysanthemum could reduce intracellular ROS levels and improve UVB-induced photoaging.Handelin is an important active ingredient in chrysanthemum.Recent evidences have shown that handelin protects against hyperosmolar induced cell death,inhibits neuroinflammation and improves the hatching rate of zebra fish eggs by activating Hsp70.Inflammation contributes to the development of sarcopenia and the therapeutic potential of anti-inflammatory strategies is of great interest.However,there are still few studies on handelin in delaying aging and sarcopenia,whose mechanism remains unclear.In this study,Caenorhabditis elegans(C.elegans),a simple model organism,was used to study the effect of handelin.The results showed that ethanol and water extracts of wild chrysanthemum and handelin all extend lifespan of C.elegans.Transcriptome sequencing showed that the differentially expressed genes were all genes of handelin treatment involved in REDOX reactions.In addition,handelin reduced ROS levels,increased mitochondrial number and maintained mitochondrial morphology.An assessment of the motility of C.elegans by the rate of pharyngeal pump and body swing as well as structure of muscle fibers showed that handelin increased healthspan of C.elegans,which also represents handelin delayed aging.These results suggested that handelin can reduce ROS levels and improve motor function to extend lifespan and healthspan in C.elegans.Based on the effect of handelin on improving motor function of C.elegans,we explored handelin on mouse myoblast C2C12 in vitro.We found that handelin promoted the differentiation of C2C12 cells into myotubes and increased the number,length and diameter of myotubes.Up-regulated the protein expression of Myo D and Myogenin,markers of early differentiation and My HC and MYH2,markers of late differentiation and maturation.The effects of handelin treatment on TNF-α-induced atrophy in C2C12 myotubes were evaluated by Immunohistochemistry or immunofluorescence and westblotting to determine myotube and the expression levels of myosin heavy chain and anabolic-related proteins.We found that handelin improved TNF-α-induced muscle atrophy,promoted protein synthesis signaling pathway by increasing phosphorylation of Akt,phosphorylation of p70S6 K and expression of 4EBP1,inhibited protein degradation by decreasing ubiquitination and phosphorylation of P65 and IκBα.These results suggested that handelin ameliorated TNF-α-induced muscle atrophy by regulating protein synthesis and degradation,which maybe by inhibiting NF-κB pathway.Next,the effects of handelin on LPS-induced muscle atrophy and natural aging mice.Body weight,food intake,muscle weight,grip strength,turn bar test,running test and muscle histology were assessed.The expression levels of muscle massrelated and function-related proteins were analysed by immunoblotting or immunostaining.Results showed that handelin not only maintained body weight and improved muscle atrophy in LPS-stimulated mice and natural aging mice by increasing food intake,but also improved motor function.In conclusion,our findings demonstrate the effects of handelin on extending lifespan and healthspan of C.elegans by reducing ROS level and improving motor function and also boosting skeletal muscle mass and muscle function maybe through the sequential activation of AKT/S6 K and inhibition of NF-κB pathway.Taken together,our results suggest that handelin represents a potential drug to delay aging and prevent muscle wasting and weakness related to aging or treating sarcopenia.