Kass, D. | Search bioRxiv

bioRxiv2019

Nuclear GAPDH signaling mediates pathological cardiac hypertrophy

Here we report that stress-induced nuclear translocation of GAPDH mediates heart hypertrophy via Brahma-Related-Gene-1 (BRG1)-associated chromatin remodelling. In response to pressure overload elicited by transverse aortic constriction, we observed nuclear translocation of GAPDH in the mouse heart. We also demonstrated a robust nuclear localization of GAPDH in cardiomyocytes from patients with dilated hypertrophic cardiomyopathy, whereas negligible GAPDH in the nucleus in control subjects. This is the first demonstration of disease-associated nuclear GAPDH directly in living patients. Using immunohistochemical methods and a pharmacological way that selectively blocks GAPDH nuclear translocation (RR compound), we proved the causal involvement of GAPDH cysteine-150 modification in this translocation in Gq-induced cell model for heart hypertrophy. Accordingly, both pharmacological and genetic interventions proved that the same mechanism played a causal role for heart hypertrophy and dysfunction in vivo. We discovered that, upon nuclear translocation, GAPDH augmented the protein interaction of BRG1 and histone deacetylase 2 (HDAC2), which further facilitated the Myh7/Myh6 isoform ratio from the mature to immature status, an essential mechanism for heart hypertrophy. Beyond medical implications, we provide a novel mechanism of stress-induced reversion of a cellular phenotype from adult to fetal state, which is mediated by a "moonlighting" function of GAPDH.

molecular biology↗

bioRxiv2019

Large particle fluorescence-activated cell sorting enables high quality single cell RNA-sequencing and functional analysis of adult cardiomyocytes

RationaleSingle cell RNA sequencing (scRNA-seq) has emerged as a powerful tool to profile the transcriptome at single cell resolution, enabling comprehensive analysis of cellular trajectories and heterogeneity during development and disease. However, the use of scRNA-seq remains limited in cardiac pathology owing to technical difficulties associated with the isolation of single adult cardiomyocytes (CMs).\n\nObjectiveWe investigated the capability of large-particle fluorescence-activated cell sorting (LP-FACS) for isolation of viable single adult CMs.\n\nMethods and ResultsWe found that LP-FACS readily outperforms conventional FACS for isolation of struturally competent CMs, including large CMs. Additionally, LP-FACS enables isolation of fluorescent CMs from mosaic models. Importantly, the sorted CMs allow generation of high-quality scRNA-seq libraries. Unlike CMs isolated via previously utilized fluidic or manual methods, LP-FAC-isolated CMs generate libraries exhibiting normal levels of mitochondrial transcripts. Moreover, LP-FACS isolated CMs remain functionally competent and can be studied for contractile properties.\n\nConclusionsOur study enables high quality dissection of adult CM biology at single-cell resolution.

cell biology↗