Project description:Zinc dyshomeostasis has been involved in the pathogenesis of cardiac hypertrophy; however, the dynamic regulation of intracellular zinc and its downstream signaling in cardiac hypertrophy remain largely unknown. Here we screened ZIP (SLC39) family members that were responsible for zinc uptake in a phenylephrine (PE)-induced cardiomyocyte hypertrophy model. We found that Slc39a2 was the only member that was altered at mRNA level by PE treatment in neonatal rat ventricular myocytes (NRVMs), but its protein level was not affected. Zincpyr1 staining showed a significant decrease in zinc uptake after PE treatment or after Slc39a2 knockdown in NRVMs, indicating an inhibition of its transport activity during hypertrophy. Slc39a2 deficiency caused spontaneous hypertrophy in NRVMs, and further exacerbated the hypertrophic responses after PE treatment. RNA sequencing analysis confirmed a largely aggravated pro-hypertrophic transcriptome reprogramming after Slc39a2 knockdown. Interestingly, the innate immune pathways, including NOD signaling, TOLL-like receptor, NFB, and IRFs, were substantially enriched after Slc39a2 knockdown. Whereas IRF7, the most sensitive among all IRFs, did not mediate the effect of Slc39a2 in hypertrophy, pro-hypertrophy phosphorylations of NFB and STAT3 were significantly enhanced after Slc39a2 knockdown, in parallel with degradation of IkBα protein. Our data demonstrate that SLC39A2-mediated zinc homeostasis contributes to the remodeling of innate immune signaling in cardiomyocyte hypertrophy, and provide novel insights into the pathogenesis of heart failure and its treatment.
Project description:Right ventricular heart failure (RVF) associated with pulmonary hypertension (PH) is characterized by a distinct gene expression pattern when compared with functional compensatory hypertrophy. Carvedilol treatment after RVF has been established reduces right ventricle (RV) hypertrophy and improves the RV function. In addition, carvedilol treatment has been shown to alter the gene expression of select genes. We sought to identify, on a genome-wide basis, the effect of carvedilol on gene expression. RVF was induced in male Sprague-Dawley rats by the combination of VEGF-receptor blockade and chronic hypoxia; thereafter, one group was treated with carvedilol. RNA was isolated from the RV and subjected to microarray analysis. A prediction analysis of the carvedilol-treated RVs showed that carvedilol treated RVs most resembled in their expression pattern the RVF pattern. However, an analysis beyond the boundaries of the prediction set revealed a small set of genes associated with carvedilol reversal of RVF. Pathway analysis of this set of genes revealed expression changes of genes involved in cardiac hypertrophy, mitochondrial dysfunction, protein ubiquitination, and sphingolipid metabolism. Genes encoding proteins in the cardiac hypertrophy and protein ubiquitination pathways were downregulated in the RV by carvedilol, while genes encoding proteins in the mitochondrial dysfunction and sphingolipid metabolism pathways were upregulated by carvedilol.