Pivotal Role Of A Disintegrin And Metalloproteinase With Thrombospondin Motifs 2 In Cardiac Hypertrophy Induced By Pressure Overload

Aims:Heart failure,which caused by cardiovascular diseases,now has become one of the most important problems of public health.Cardiac hypertrophy is gradually considered as an adapted alteration results from various stimulating factors and a critical node during the development of heart failure.It is of great value to clarify the mechanism of the development of cardiac hypertrophy,find the specific molecule and its relavant signaling pathway and investigate the new therapy target in the prevention of cardiac hypertrophy.During the experiment,we attempted to clarify the effect of ADAMTS2 and the exactly mechanism on the process of cardiac hypertrophy.MethodsIn the experiment,with the use of ADAMTS2-knockout and cardiomyocyte specific ADAMTS2-overexpressing transgenic mice,we built pressure overload induced cardiac hypertrophy model by aortic banding surgery and used echocardiography,H&E-,PSR-,WGA-staining and PCR analysis to evaluate the extent of cardiac hypertrophy after the aortic banding treatment;Meanwhile,we isolated and cultured the neonatal rat cardiomyocytes.Then the neonatal rat cardiomyocytes were infected with AdshADAMTS2 or AdADAMTS2 to knockdown or overexpress ADAMTS2,respectively and administered with Ang Ⅱ to cause neonatal rat cardiomyocyte hypertrophy.With the use of immunostaining and PCR analysis,we evaluated the extent of neonatal rat cardiomyocyte hypertrophy after the administration of Ang II.With the above experiments both in vivo and in vitro,we investigate the effect of ADAMTS2 on the development of cardiac hypertrophy.In the following experiment,we performed the Western blot assay to test the protein level of relavant signaling pathway during the process of cardiac hypertrophy in both murine heart samples and neonatal rat cardiomyocytes.In addition,we added the specific inhibitor of the relavant signaling pathway in murine aortic banding model to decrease the activation of the signaling pathway,used pathological and molecular biologic methods to evaluate the extent of cardiac hypertrophy,confirmed the effect of ADAMTS2 on the development of cardiac hypertrophy is dependent on this signaling pathway and clarified the exactly mechanism of ADAMTS2 in the process of cardiac hypertrophy.ResultsWestern blot results suggested that in a murine model of aortic banding induced cardiac hypertrophy and in a vitro model of Ang II induced neonatal rat cardiomyocyte hypertrophy exhibited dramatically increased ADAMTS2 protein expression.In vivo experiments of aortic banding induced cardiac hypertrophy murine model,the results suggested that loss of ADAMTS2 aggravates pressure overload induced cardiac hypertrophy while overexpression of ADAMTS2 in the heart attenuates pressure overload induced cardiac hypertrophy;the similar results were found in cell studies of Ang II induced neonatal rat cardiomyocyte hypertrophy model in vitro.The neonatal rat cardiomyocytes were isolated and infected with AdshADAMTS2 or AdADAMTS2 to knockdown or overexpress ADAMTS2,respectively.The results showed that ADAMTS2 knockdown notably enhanced Ang II-induced cardiomyocyte hypertrophy while the overexpression of ADAMTS2 in neonatal rat cardiomyocytes resulted in attenuated hypertrophic alterations.The following Western blot results suggested that the protective role of ADAMTS2 in pathological cardiac hypertrophy is mediated by the PI3K-AKT signaling pathway.With the administration of PI3K specific inhibitor LY294002 to cause the inactivation of PI3K-AKT signaling pathways reversed pressure overload induced cardiac hypertrophy in ADAMTS2-KO mice.ConclusionIn summary,our present experiments both in vivo and in vitro indicated that ADMATS2 has a protective role in the development of cardiac hypertrophy.The exactly mechanism of ADAMTS2 is relying on the inactivation of PI3K-AKT signaling pathways.As the findings above in our study,we preclude that effective intervention on ADAMTS2 might be a promising and novel target for clinical prevention and treatment with cardiac hypertrophy.