Study On The Effect Of Potassium Channel Protein Shaker And Deacetylase HDAC3 On The Heart Failure Of Drosophila

Objective: Heart failure is a complex disease,the final stage of the development of various heart diseases,including arrhythmia and cardiomyopathy.Potassium channels participate in the repolarization of action potential of myocardial cells,which is closely related to the occurrence of arrhythmia;As the first potassium channel identified in Drosophila,the molecular mechanism of shaker in heart failure is still unclear.HDAC3,as a histone deacetylase,is involved in the regulation of cardiac lipid metabolism,but whether it depends on the activity of deacetylase,and its relationship with heart failure is unclear.In this study,Drosophila melanogaster was used as a model to explore the function of potassium channel protein shaker in the occurrence and development of heart failure and the molecular biological mechanism of HDAC3 involved in cardiac lipid metabolism,in order to clarify the molecular mechanism of heart failure.Methods: In this study,we used the heart specific promoter hand4.2 gal4 to specifically knock down the expression of potassium channel protein shaker or acetylase HDAC3 in Drosophila melanogaster;Drosophila melanogaster was fed with30% coconut oil as high-fat diet group;High frequency electrical stimulation was used to simulate the stress state of heart,and the incidence of heart failure under certain pressure load was observed;Drosophila adult heart physiological function analysis system was used to analyze the heart phenotype of heart specific knockdown Drosophila;The effect of survival curve analysis on life span of Drosophila melanogaster;Triglyceride test kit was used to detect the level of TAG;RQ-PCR was used to detect the expression level of HDAC3 lipid metabolism gene.Results:(1)The incidence of heart failure was significantly increased by high frequency electric stimulation of shaker gene mutation.(2)The heart specific knockdown of shaker gene significantly increased the arrhythmia index of Drosophila at 5weeks of age.(3)The cardiac specific knockdown of shaker will significantly reduce the life span of Drosophila.(4)High fat diet increased the level of TAG and decreased cardiac systolic function in Drosophila melanogaster.(5)The specific knockdown of HDAC3 by hand gal4 led to the increase of TAG level in Drosophila heart and even the whole body,but RQ-PCR did not change the expression level of lipid metabolism related genes in the heart.(6)Mhc-gal4,lsp-gal4,or Prome-gal4 specifically knock down HDAC3 in muscle(including cardiomyocytes),adipose tissue,and oenocyte similar to mammalian liver function,respectively,Drosophila did not observe the change of whole body TAG level,which was consistent with the Smr knock-down phenotype of inhibition complex member.(7)HDAC3overexpression can reverse the increase of TAG level induced by high fat diet.(8)The transgenic res HDAC3 K26 A,a deacetylase active mutant,could not reverse the TAG increase caused by knockdown of HDAC3.(9)The deacetylase activity of HDAC3 is involved in the regulation of TAG level in vivo.(10)Knocking down HDAC3 can shorten the life span of Drosophila,and highfat diet can further shorten the life span of Drosophila.Conclusion:(1)Shaker mutation resulted in the decrease of anti stress ability of Drosophila heart.(2)The potassium channel protein shaker maintains the physiological function of the heart of aged Drosophila melanogaster,and the specific knockdown of shaker gene affects the lifespan of Drosophila melanogaster.(3)The increase of TAG level and the decrease of cardiac contractility in Drosophila fed with high-fat diet lead to the occurrence of lipotoxic cardiomyopathy.(4)HDAC3 is involved in regulating the level of TAG in vivo,but it is not the function of HDAC3 in cardiomyocytes,which may be related to the knockdown of HDAC3 in lymphoid tissue.(5)The regulation of TAG level by HDAC3 depends on K26 A enzyme activity site,the increase of TAG level is not the main cause of cardiomyopathy in HDAC3 knockdown Drosophila.(6)Knocking down HDAC3 can shorten the life span of Drosophila,and high-fat diet can further shorten the life span of Drosophila.