Study On The Regulation Of AMPK/PPARα/SCAD Signal Pathway In Cardiac Hypertrophy

Objective:To study the role of short-chain acly-coenzyme A dehydrogenase (SCAD) in cardiachypertrophy and the effect of AMPK/PPARα signaling pathway on SCAD.Methods:(1) The cardiomyocytes were treated with the interference sequence of SCAD, theexpression and enzyme activity change of SCAD were determined by Western blotting,Real-time PCR and the method to determine enzyme activity. The cardiomyocytes weretreated with the optimal sequence1186of SCAD, the expression and enzyme activitychange of SCAD, the mRNA level of related gene atrial natriuretic factor (ANF) andbrain natriuretic peptide (BNP) and the changes of cardiomyocyte surface area and freefatty acids were determined, furthermore, compared with the cardiac hypertrophy modelinduced by PE.(2) The cardiomyocytes were treated with fenofibrate (10μmol/L) for24hours andsubsequently stimulated with1186, then, the changes of cardiomyocyte surface area,the enzyme activity of SCAD and free fatty acids, the protein and mRNA pression ofSCAD, PPARα were observed, in addition, the mRNA level of ANF and BNP wasobserved. Cardiomyo-cytes were treated with PE for24hours or fenofibrate pretreated for30min and subsequently stimulated with PE for24hours, then, the changes ofcardiomyocyte surface area, the enzyme activity of SCAD and free fatty acids, theprotein and mRNA pression of SCAD, PPARα were observed, and the mRNA level ofANF and BNP was tested at the same time.(3) Cardiomyocytes were treated with PE for24hours or AICAR(0.5mmol/L) pretreatedfor30min and subsequently stimulated with PE for24hours, then, the changes ofcardiomyocyte surface area, the enzyme activity of SCAD and free fatty acids, theprotein and mRNA pression of SCAD, PPARα and p-AMPKα (T172) were observed,and the mRNA level of ANF and BNP was tested at the same time.Results:(1) Compared with control group, the expression of ANF and BNP at mRNA level, thecardiomyocyte surface area and free fatty acids were increased obviously, the enzymeactivity of SCAD decreased obviously in1186group. The effect of optimal sequence1186and PE on cardiomyocytes was the same.(2) The cardiomyocytes were pretreated with fenofibrate for24hours and subsequentlystimulated with1186induced cardiac hypertrophy model, the expression of SCAD andPPARα and enzyme activity of SCAD increased obviously, on the contrary, ANF andBNP mRNA level significantly decreased. Compared with control group, thecardiomyocytes were treated with PE for24hours, the protein and mRNA expression ofSCAD, PPARα and p-AMPKα (T172) were significantly decreased, the cardiomyocytesurface area and free fatty acids were increased obviously.(3) Compared with PE group, the protein and mRNA levels of SCAD, PPARα andp-AMPKα (T172) were significantly up-regulated, and the change of the cardiomyocytesurface area and the content of free fatty acid were obviously decreased incardiomyocytes pretreated with fenofibrate or AICAR for30min.Conclusion:(1) The expression of SCAD decreased obviously in cardiac hypertrophy, furthermore,knocking down of SCAD caused cardiac hypertrophy, which showed thatdown-regulation of SCAD was closely related with cardiac hypertrophy. (2) The change trend of PPARα is consistent with SCAD, fenofibrate can raise theexpression and enzyme activity of SCAD, reverse cardiac hypertrophy thatcardiomyocytes were treated with the interference sequence of SCAD or PE. Thechange trend of p-AMPKα and PPARα/SCAD is consistent. The cardiomyocytes werepretreated with AICAR, the expression of PPARα/SCAD were up-regulated, cardiachypertrophy induced by PE was reversed, which have protective effects on cardiachypertrophy, the results showed that AMPK/PPARa/SCAD signal pathway may regulatecardiac hypertrophy directly.