Transcriptome remodeling of mouse hearts during postnatal cardiac maturation and under proteotoxic stress.

backgroundDesmin-related cardiomyopathy (DRC) is a proteotoxic disorder driven by mutations in DES and related genes such as CRYABR120G (R120G), leading to progressive cardiac dysfunction. While late-stage transcriptomic changes in cardiomyopathy and aging are well studied, early molecular events during postnatal maturation and disease onset remain poorly defined. METHODS AND

resultsThrough RNA sequencing of mouse ventricular myocardium at multiple time points, we uncovered novel transcriptional changes associated with postnatal cardiac development in non-transgenic mice, as well as early alterations preceding overt pathology in the R120G-based DRC mice. RT-qPCR and western blotting confirmed the kinase SBK2 was downregulated in multiple DRC mouse models, suggesting a conserved role in disease progression. Comparative analysis of our sequencing datasets and an independent RNA-seq dataset, identified a conserved molecular signature involving autophagy and proteasome pathways, notably including the proteasome subunit Psmd5. Profiler enrichment analysis uncovered shared transcription factor binding motifs implicating a previously unrecognized transcriptional regulator in disease progression.

conclusionsThese findings identify Sbk2, Psmd5, Scml4, Snai3, and Foxn4 as novel candidates in DRC pathogenesis. In the non-transgenic heart, data implicate several transcriptional networks governing the shift from cardiac maturation to detrimental aging including AW551984 and a group of zinc finger C2H2 transcription factors (Zfp41, Zfp273, Zfp456, Zfp469, and Zfp820). These genes have not been studied in the context of cardiac maturation hinting at an unexplored cardiac regulatory network. These findings may provide novel mechanistic insights into the transition from postnatal cardiac maturation to detrimental cardiac aging and proteotoxic stress.