Dopamine Mechanism And Transcriptome Analysis Of Olfactory Learning In Drosophila Melanogaster Induced By Chronic Stress

Drosophila melanogaster is one of the most successful mainstream genetic animals with a wealth of molecular genetic tools and accumulated over a hundred years of research.Drosophila model has achieved great success in the study of both memory and stress.Drosophila model found a number of evolutionarily conserved regulatory mechanisms at the molecular and cellular levels.Although the regulation of memory and its circuits by environmental stress is a hot area in current neurobiology research,the study of fruit flies as an animal model is rare.Especially for the mechanism research of the effects of chronic stress and regulating learning and memory,there isn't almost model of Drosophila.In the previous work,a fruit fly is chronic stress model was established in the laboratory.It was found that the fruit flies olfactory learning ability was severely impaired,while anti-stress neuropeptide F had the effect of protecting olfactory learning from chronic stress damage after four days of chronic stress treatment.This study explored the dopamine mechanism of Drosophila olfactory learning impaired by chronic stress.And using high-throughput sequencing technology(RNA-seq)for transcriptome differential expression analysis to identify relevant candidates for stress-regulated olfactory memory.1.Changes of dopamine signal and its effect on olfactory learning ability of Drosophila under chronic stress conditions.First of all,L-DOPA was used to feed that had been treated with chronic stress.The results showed that the olfactory learning ability of fruit flies became worse.On the contrary,feeding 3IY can save the olfactory learning ability damaged by chronic stress.Secondly,overexpression of dopamine receptors in mushroom bodies can cause serious damage to the olfactory learning ability of fruit flies.The olfactory learning ability of Drosophila melanogaster with a heterozygous deletion mutant of dopamine receptor Dop1R1,was significantly resistant to chronic stress.Finally,at the neuronal level,the artificial activation of dopamine neurons for four consecutive days is sufficient to replace the oscillations and result in a significant deterioration of the olfactory learning ability of fruit flies.In turn,blockade of neurotransmitter release from dopamine neurons during vortex treatment can protect olfactory learning memory from chronic stress.Interestingly,only the need to block MB-MP1 dopamine neurons is sufficient to play the above protection.In summary,the results of this study suggest that chronic stress damage to fruit flies learning ability is due to overactive dopamine signaling during chronic stress management.2.Protective effects of NPF neurons on olfactory learning in Drosophila melanogasterOur previous work in this laboratory showed that overexpression of NPF neuropeptides can protect drosophila olfactory learning ability from chronic stress.This study found that artificial activation of NPF neurons during shock processing can also protect learning ability.This result further proves the previously proposed hypothesis that NPF release neuropeptide NPF protects olfactory learning ability from chronic stress.Interestingly,although only one NPF receptor gene,NPFR,has been found in the Drosophila genome so far,RNAi knockdown of NPFR only shows weaker olfactory learning deficits.Therefore,the downstream neural circuit of NPF neuropeptide remains to be further studied.3.Transcriptome Differential Profiling Analysis of Chronic StressDifferential expression analysis of transcriptome data at five time points in the chronic stress process revealed 882 differentially expressed genes.A total of 610 genes were found to have an expression pattern similar to that of NPF by cluster analysis of transcriptome sequencing data based on the expression pattern of NPF.In addition,47 learning-memory-related genes were selected.These candidate genes are enriched with genes associated with the ability to learn chronic stress damage.