Cellular and molecular landscape of mammalian sinoatrial node revealed by single-cell RNA sequencing

Dandan Liang,Liping Zhou,Yi-Han Chen,Bo Lv,Yi Liu,Zhigang Xue,Li Li,Jinfeng Xue,Qiao Zeng,Huixing Zhou,Duanyang Xie,Li Geng,Jian Yang,Fulei Zhang,Jie Liu,Ke Xiong

doi:10.1038/s41467-020-20448-x

Dandan Liang, Liping Zhou + Show 14 more

Open Access

https://doi.org/10.1038/s41467-020-20448-x

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Abstract

Bioelectrical impulses intrinsically generated within the sinoatrial node (SAN) trigger the contraction of the heart in mammals. Though discovered over a century ago, the molecular and cellular features of the SAN that underpin its critical function in the heart are uncharted territory. Here, we identify four distinct transcriptional clusters by single-cell RNA sequencing in the mouse SAN. Functional analysis of differentially expressed genes identifies a core cell cluster enriched in the electrogenic genes. The similar cellular features are also observed in the SAN from both rabbit and cynomolgus monkey. Notably, Vsnl1, a core cell cluster marker in mouse, is abundantly expressed in SAN, but is barely detectable in atrium or ventricle, suggesting that Vsnl1 is a potential SAN marker. Importantly, deficiency of Vsnl1 not only reduces the beating rate of human induced pluripotent stem cell - derived cardiomyocytes (hiPSC-CMs) but also the heart rate of mice. Furthermore, weighted gene co-expression network analysis (WGCNA) unveiled the core gene regulation network governing the function of the SAN in mice. Overall, these findings reveal the whole transcriptome profiling of the SAN at single-cell resolution, representing an advance toward understanding of both the biology and the pathology of SAN.

Highlights

Bioelectrical impulses intrinsically generated within the sinoatrial node (SAN) trigger the contraction of the heart in mammals
We found that the expression pattern of Vsnl[1], Dlgap[1], and Unc[80] was similar to that of Hcn[4], which is relatively highly expressed in SAN compared to atrium and ventricle (Fig. 2a), though the transcriptional level of Unc[80] was lower than that of Vsnl[1] and Dlgap[1] in SAN (Supplementary Fig. 4)
We found that the SAN cells in mice can be divided into four clusters, including one core cell cluster, whereas SAN cells in rabbit and cynomolgus monkey can be divided into three clusters, each of which contains a core cell cluster

Summary

Introduction

Bioelectrical impulses intrinsically generated within the sinoatrial node (SAN) trigger the contraction of the heart in mammals. Weighted gene co-expression network analysis (WGCNA) unveiled the core gene regulation network governing the function of the SAN in mice. Overall, these findings reveal the whole transcriptome profiling of the SAN at single-cell resolution, representing an advance toward understanding of both the biology and the pathology of SAN. The pacemaker activity of SAN cells originates from the synergistic effect of ion channels, transporters, and Ca2+ regulators[3,5,6] It is tightly regulated by autonomic nerve signaling[7]. With the advantage of single-cell RNA sequencing (scRNA-seq) more expressed genes can be detected and used for comprehensive analysis of cell subtype and regulatory network at transcriptome level. The consistency of its abundant expression in SAN across species makes it a possible candidate marker gene in other two species as well

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