Single-cell transcriptomic heterogeneity between conduit and resistance mesenteric arteries in rats

Area of Science:

• Vascular Biology
• Cellular and Molecular Medicine
• Genomics and Transcriptomics

Background:

• Endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) exhibit functional heterogeneity across different vascular segments, despite morphological similarities.
• Extrapolation of findings from large arteries to resistance vasculature is often inconsistent, indicating a need to understand cell-specific differences at the arteriolar level.

Purpose of the Study:

• To investigate the phenotypic differences between ECs and VSMCs from large (>300 µm) and small (<150 µm) mesenteric arteries at the single-cell level.
• To identify distinct subpopulations and molecular pathways contributing to vascular heterogeneity between conduit and resistance arteries.

Main Methods:

• Single-cell RNA sequencing (scRNA-seq) using 10x Genomics on enzymatically digested ECs and VSMCs from rat mesenteric arteries of different sizes.
• Bioinformatic analysis including data normalization, unsupervised clustering, Uniform Manifold Approximation and Projection (UMAP) visualization, and differential gene expression analysis.
• Gene Ontology (GO) analysis to identify differing biological pathways between cell types and artery sizes.

Main Results:

• Identification of 630 differentially expressed genes (DEGs) in ECs and 641 DEGs in VSMCs between large and small mesenteric arteries.
• Discovery of 562 distinct biological pathways in ECs and 270 in VSMCs differing between artery sizes.
• Characterization of eight unique EC subpopulations and seven unique VSMC subpopulations, each with identified DEGs and pathways.

Conclusions:

• Significant single-cell phenotypic heterogeneity exists between ECs and VSMCs in conduit versus resistance arteries.
• The identified DEGs and pathways provide a foundation for understanding the mechanisms underlying vascular heterogeneity.
• This dataset supports the discovery of novel hypotheses regarding the functional specialization of vascular cells in different circulatory regions.