Cardiac tissue inhibitor of matrix metalloprotease 4 dictates cardiomyocyte contractility and differentiation of embryonic stem cells into cardiomyocytes: Road to therapy

Abstract

Background TIMP4 (Tissue Inhibitors of Matrix Metalloprotease 4), goes down in failing hearts and mice lacking TIMP4 show poor regeneration capacity after myocardial infarction (MI). This study is based on our previous observation that administration of cardiac inhibitor of metalloproteinase (~TIMP4) attenuates oxidative stress and remodeling in failing hearts. Therefore, we hypothesize that TIMP4 helps in cardiac regeneration by augmenting contractility and inducing the differentiation of cardiac progenitor cells into cardiomyocytes. Methods To validate this hypothesis, we transfected mouse cardiomyocytes with TIMP4 and TIMP4-siRNA and performed contractility studies in the TIMP4 transfected cardiomyocytes as compared to siRNA-TIMP4 transfected cardiomyocytes. We evaluated the calcium channel gene serca2a (sarcoplasmic reticulum calcium ATPase2a) and mir122a which tightly regulates serca2a to explain the changes in contractility. We treated mouse embryonic stem cells with cardiac extract and cardiac extract minus TIMP4 (using TIMP4 monoclonal antibody) to examine the effect of TIMP4 on differentiation of cardiac progenitor cells. Results Contractility was augmented in the TIMP4 transfected cardiomyocytes as compared to siRNA-TIMP4 transfected cardiomyocytes. There was elevated expression of serca2a in the TIMP4 transformed myocytes and down regulation of mir122a. The cells treated with cardiac extract containing TIMP4 showed cardiac phenotype in terms of Ckit+, GATA4+ and Nkx2.5 expression. Conclusion This is a novel report suggesting that TIMP4 augments contractility and induces differentiation of progenitor cells into cardiac phenotype. In view of the failure of MMP9 inhibitors for cardiac therapy, TIMP4 provides an alternative approach, being an indigenous molecule and a natural inhibitor of MMP9.

Epigenetic silencing of TIMP4 in heart failure

“…We performed real time expression of three microRNAs‐122a, 29b and 455‐5p since we found in our previous reports that mir29b and 455‐5p regulate the levels of MMP9 and mir122a is associated with TIMP4 expression . We observed up‐regulated expression of mir122a and down‐regulated expression of mir29b and 455‐5p (Fig.…”

“…We hypothesize that in heart failure these CpG islands get methylated which leads to the silencing of the TIMP4 gene. In our previous study , we discovered that when TIMP4 is expressed in myocytes there is decrease in the expression of microRNA122a along with increased levels of serca2a. In this study, we evaluated whether diminished expression of TIMP4 is affected by mir122a.…”

Mitochondrial pathways to cardiac recovery: TFAM

“…In vitro cardiomyocyte contractility analysis via transfection of TIMP-4 (an MMP-9 inhibitor) led to an up regulation of serca2a and its regulator mir122a [144]. Up regulation of TFAM via an exosomal vehicle will not only regulate MMP activity but also calpain proteases (Fig 3).…”

Gene Expression Profiling of H9c2 Cells Subjected to H₂O₂-Induced Apoptosis with/without AF-HF001

“…Structural remodeling of the extracellular matrix is an important contributor to abnormal ventricular TIMP4 inhibits MMP-mediated degradation of excess extracellular matrix and reduces myocardial infarction in vivo in I/R mice. 17) Chaturvedi et al 18) reported that TIMP4 attenuates oxidative stress and induces the differentiation of cardiac progenitor cells into cardiomyocytes. Our data demonstrated that TIMP4 expression upon H 2 O 2 treatment (−1.85-fold) was up-regulated in cells that were also treated with AF-HF001 (1.97-fold).…”