A Genetic Screen For Neuropeptides That Regulate The Autophagic Flux In The Drosophila Brain

Biological organisms are in a dynamically changing environment,and the body produces a series of non-specific adaptive responses to internal and external environmental stimuli,a process called stress.Stress plays an important role in maintaining the homeostasis of the internal environment of cells or individuals,but stress that is too intense or prolonged can cause metabolic disorders and organ dysfunction in the body,which can lead to the occurrence of diseases.In recent years,stress mechanism has become a hot topic of scientific exploration,and some studies have found that autophagy is one of the key mechanisms of cellular stress response,which is very important for maintaining intracellular homeostasis.Autophagic dysfunction is associated with a variety of diseases.For example,during the onset of neurodegenerative diseases,abnormal accumulation of autophagosomes causes intraneuronal homeostasis imbalances,resulting in neuronal dysfunction.In line with the importance of autophagy,many intracellular signaling pathways and extracellular signaling molecules are involved in the regulation of autophagy.Neuropeptides are endogenous active substances released by neurons in the nervous system and have extensive and significant effects on neurophysiology and behavior.Studies have shown that neuropeptides can influence the progression of neuropathology by regulating autophagy,but their mechanisms have not been elucidated.In this study,we used the genetic advantages of Drosophila genetic model animals to screen for neuropeptides that can regulate autophagic flux in the brain.This study collected chemical junction mutant strains covering almost all neuropeptide genes in the genome.Determine whether the autophagy stream is blocked by monitoring the levels of the autophagy markers Ref(2)p/p62 and Atg8a/LC3 proteins.The screening results showed that there were four neuropeptide mutants,including Ast A,ETH,CAPA and NPF,whose protein expressions in the brains of Ref(2)p and Atg8a-II/Atg8a-I were upregulated,suggesting that the autophagic flux of Drosophila brain cells was blocked.Since these mutants are all dysfunctional mutants,the function of the above 4 screening-positive genes should be related to the promotion of autophagy.To further validate this hypothesis,this study used temperature genetics to activate Ast A neurons during chronic stress processing and found that the activity of Ast A neurons can prevent autophagic flux blockade induced by chronic stress.Since promoting autophagy levels is effective in preventing chronic stress-induced autophagy flux blockade,this result supports the hypothesis that Ast A neuronal activity can promote autophagy.In summary,the genetic screening and verification of this study found that neuropeptides such as Ast A have an important regulatory effect on the overall autophagic flux of the brain.