A single-cell transcriptomic inventory of murine smooth muscle cells [aorta]

Smooth muscle cells (SMC) execute important physiological functions in numerous vital organ systems, including the vascular, gastrointestinal, respiratory and urogenital tracts. SMC differ morphologically and functionally at different anatomical locations, but the molecular underpinnings of these differences remain poorly understood. Here, using deep single-cell RNA sequencing combined with in situ gene and protein expression analysis in four organs - heart, aorta, lung and colon - we reveal the molecular basis for high-level differences between vascular, visceral and airway SMC, and more subtle differences between SMC in elastic versus muscular arteries as well as zonation of elastic artery SMC along the direction of blood flow. Arterial SMC exhibit extensive organotypic heterogeneity, whereas venous SMC conversely display high similarity across organs. We further identify a unique SMC phenotype of terminal pulmonary arterioles. This study provides the first comparative SMC cross-organ resource, offering new insight into SMC subtypes and their specific functions. single-cell transcriptomes were generated of individual cells captured from adult male mice (8-21 weeks of age) by single-cell RNA-sequencing