Abstract 4359847: RNA Binding Protein in Proliferative Cardiomyocytes: a Cross-species Meta-analysis from Mouse, Pig, and Human Transcriptomic Profiling Data

Background: In regenerative hearts, robust cardiomyocyte (CM) proliferation was observed in mice that underwent myocardial infarction on postnatal (P) day 1 (MI P1 ) and pigs that underwent P1 apical resection followed by P28 myocardial infarction (AR P1 MI P28 ). Regulators promoting CM proliferation were discovered by analyzing transcriptomic data generated from these models. Most of these regulators supported mRNA production of cell-cycle machinery; yet the mRNA required translation into functional protein and required the activity of RNA-binding proteins (RBPs). The relationship between RBP and the cell cycle in CM is an open question. Hypothesis: The RBP expressions strongly correlate with the CM cell cycle in mice, pigs, and humans. Approach: We performed a meta-analysis to study the relationship between RBP expression and CM proliferation. In mouse and pig CM proliferation, the single-nuclei RNA-sequencing (snRNAseq) data from regenerating mouse (Gene Expression Omnibus GSE130699) and pig (GSE185289) hearts were reanalyzed via an Autoencoder with a focus on RBP expression. We also analyzed bulk RNA-sequencing, via DeSeq2 software, from two human-induced pluripotent stem cell-derived (hiPSC) cardiomyocyte (hiPSC-CM) cell lines (GSE289839); the first cell line was harvested sixteen days (hiPSC-CM-D16) after differentiation, when the cells still actively proliferated; the second cell line, hiPSC-CM-D140, was harvested when the cells ceased cell cycle. Then, the RBPs associated with mouse, pig, and hiPSC-CM were compared across species. Protein expressions of RBPs, which were consistently upregulated in proliferating CM among the three species, were examined in pig CMs via immunohistological analysis. Result: Proliferating CM was retrieved by RBP-focused analysis, where five proliferation markers AURKB, MKI67, INCENP, CDCA8, and BIRC5 co-localized. Twenty-one RBPs were found to be consistently upregulated in proliferating mouse, pig, and hiPSC-derived CMs. Histological analysis showed a significant increase of DHX9 and PTBP3 in regenerative (AR P1 MI P28 P35), compared to non-regenerative (MI P28 P35) pig hearts. Conclusion: The results demonstrated a strong relationship between RBP expression and CM proliferation.