PDF(Pubmed)
Abstract：
Understanding the mechanisms of polyploidization in cardiomyocytes is crucial for advancing strategies to stimulate myocardial regeneration. Although endoreplication has long been considered the primary source of polyploid human cardiomyocytes, recent animal work suggests the potential for cardiomyocyte fusion. Moreover, the effects of polyploidization on the genomic-transcriptomic repertoire of human cardiomyocytes have not been studied previously. We applied single-nuclei whole genome sequencing, single nuclei RNA sequencing, and multiome ATAC + gene expression (from the same nuclei) techniques to nuclei isolated from 11 healthy hearts. Utilizing post-zygotic non-inherited somatic mutations occurring during development as \"endogenous barcodes,\" to reconstruct lineage relationships of polyploid cardiomyocytes. Of 482 cardiomyocytes from multiple healthy donor hearts 75.7% can be sorted into several developmental clades marked by one or more somatic single-nucleotide variants (SNVs). At least ~10% of tetraploid cardiomyocytes contain cells from distinct clades, indicating fusion of lineally distinct cells, whereas 60% of higher-ploidy cardiomyocytes contain fused cells from distinct clades. Combined snRNA-seq and snATAC-seq revealed transcriptome and chromatin landscapes of polyploid cardiomyocytes distinct from diploid cardiomyocytes, and show some higher-ploidy cardiomyocytes with transcriptional signatures suggesting fusion between cardiomyocytes and endothelial and fibroblast cells. These observations provide the first evidence for cell and nuclear fusion of human cardiomyocytes, raising the possibility that cell fusion may contribute to developing or maintaining polyploid cardiomyocytes in the human heart.
摘要：
了解心肌细胞多倍体化的机制对于推进刺激心肌再生的策略至关重要。尽管内复制一直被认为是多倍体人心肌细胞的主要来源，最近的动物研究表明心肌细胞融合的潜力。此外，以前尚未研究多倍体化对人心肌细胞基因组-转录组库的影响.我们应用了单核全基因组测序，单核RNA测序，以及从11个健康心脏中分离出的多体ATAC+基因表达(来自相同的细胞核)技术。利用发育过程中发生的合子后非遗传体细胞突变作为内源性条形码，重建多倍体心肌细胞的谱系关系。在来自多个健康供体心脏的482个心肌细胞中,75.7%可以被分选成由一个或多个体细胞单核苷酸变体(SNV)标记的几个发育进化枝。至少约10％的四倍体心肌细胞含有来自不同进化枝的细胞，表明线性不同的细胞融合，而60％的高倍性心肌细胞包含来自不同进化枝的融合细胞。结合snRNA-seq和snATAC-seq揭示了与二倍体心肌细胞不同的多倍体心肌细胞的转录组和染色质景观。并显示一些具有转录特征的高倍性心肌细胞，表明心肌细胞与内皮细胞和成纤维细胞之间融合。这些观察结果为人类心肌细胞的细胞和核融合提供了第一个证据，提高了细胞融合可能有助于在人心脏中发育或维持多倍体心肌细胞的可能性。
