The Key Roles Of SENP3 Regulating Macrophage In Post-Myocardial Infarction Remodeling And Its Underlying Mechanisms

Objective: Macrophages are the key inflammatory cells involved in the whole process of post-myocardial infarction(MI),which have the dual functions of promoting inflammation and inhibiting inflammation.SUMOylation is a newly discovered post-translational modification of proteins.For now,there are few studies on the relationship between macrophages and SUMOylation system.As one of the key members of SUMOylation system,the de-SUMOylation enzyme SENP3 has been demonstrated as significant regulator in cardiovascular disease.However,whether macrophage SENP3 involved in ischemic heart disease has not been investigated.In this study,we will explore the effects of macrophages SENP3 on myocardial remodeling after MI and its potential molecular mechanisms.Contents:Firstly,the expression of SENP3 in macrophages during myocardial infarction were assessed by using the model of ischemic heart disease;And then,the role of macrophage SENP3 in post-myocardial infarction remodeling were determined via construction of macrophage-specific SENP3 knockout mice.Finally,the effects of macrophage SENP3 on JMJD3 SUMOylation and its protein level were investigated by molecular biological methods.Methods: Magnetic cell sorting(MACS)and flow cytometry were used to isolate the macrophages in left ventricle following myocardial infarction.And the expression of SENP3 m RNA level of macrophages were detected by quantitative real-time PCR.Macrophage-specific SENP3 knockout mice were constructed,and then the model of permanent MI was established.Four weeks after MI,left ventricular function was evaluated by echocardiography(Echo);myocardial fibrosis and remodeling were determined by Masson and Sirius red staining;the cardiac macrophage polarization and mobilization of splenic monocytes after MI were investigated by flow cytometry analysis,immunohistochemistry /immunofluorescence staining and quantitative real-time PCR.Finally,laser confocal,co-immunoprecipitation and Western Blot methods were used to study the potential molecular mechanism of SENP3 regulating macrophage polarization following MI.Results: A large number of macrophages migrated and recruited to the ischemic heart area after MI and reached the peak on the third day.The level of macrophage SENP3 m RNA was significantly up-regulated when challenged with MI.Deficiency of macrophage-specific SENP3 can not only improve left ventricular ejection fraction and shortening fraction after acute and chronic MI,but also inhibit myocardial fibrosis and remodeling.Furthermore,knockout of macrophage SENP3 inhibited the polarization of macrophages to M1pro-inflammatory macrophages and the mobilization of splenic monocytes into circulating blood.Molecular mechanism studies indicaed that the regulatory effect of SENP3 on M1 macrophage polarization depends on the expression level of histone demethylase JMJD3.Conclusion: MI can induce the up-regulation of macrophage SENP3.Knockout of macrophage SENP3 by genetic method can improve cardiac dysfunction in acute and chronic MI,which is related to the decrease of the number of monocytes infiltrated into the heart and the inhibition of macrophage M1 pro-inflammatory macrophages,thus promoting recruitment macrophages to M2 polarization phenotype.The study of molecular mechanism suggests that JMJD3 is the substrate of SENP3,and the regulation of SENP3 on macrophage polarization depends on the expression of JMJD3.Down-regulation of JMJD3 can attenuate the inhibitory effect of SENP3 deletion on the polarization of M1 macrophages.Selective intervention of macrophage SENP3 is expected to represent a new potential molecular target for the treatment of ischemic heart disease.