Single-Nuclei RNA-Sequencing Uncovers Alterations in the Transcriptional Profile of Skeletal Muscle in Peripheral Artery Disease

BACKGROUND: Lower extremity peripheral artery disease (PAD) is caused by atherosclerotic occlusion of lower limb blood vessels, impacting >200 million people worldwide. PAD causes life-altering symptomatology such as claudication, ischemic rest pain, and gangrene, with limited effective treatment options. Herein, we performed single-nuclei RNA-sequencing (snRNAseq) to facilitate a better understanding of the complex pathobiological environment within the PAD limb and intercellular communication. METHODS: Gastrocnemius muscle specimens were collected from 20 patients with PAD and 12 non-PAD controls. Patients with PAD were classified as Rutherford category 3 (severe claudication). Non-PAD participants were of similar age, body mass index and medication usage as patients with PAD. Nuclei were isolated and snRNAseq was performed. Bioinformatic analysis was conducted to determine differences in gene expression between PAD and non-PAD nuclei, as well as analysis of intercellular signaling networks. Histological analysis of muscle specimens assessed the following: myosin heavy chain fiber distributions, myofiber cross-sectional area and myofiber denervation. RESULTS: 57,364 high-quality nuclei were captured (21,417 PAD; 35,947 non-PAD) and unsupervised clustering revealed 12 distinct nuclei populations based on their transcriptional profile. Quantification of the relative abundance of nuclei populations identified several differences, including PAD muscles having a lower percentage of type I myonuclei, muscle stem cells, and endothelial cells but a higher proportion of type II and regenerating myonuclei. Differentially expressed gene analysis of myonuclei populations uncovered upregulation of genes involved in stress response, autophagy, and atrophy in patients with PAD. Ligand-receptor interactions were used to determine how PAD alters the communication between identified nuclei populations. The inferred strength of interactions was greater in non-PAD compared to PAD patients. Further, intercellular communication network analysis revealed fibro-adipogenic progenitors as a primary signaling hub in PAD muscle. CONCLUSION: snRNAseq uncovered novel transcriptional differences and intercellular communication pathways unique to PAD muscle. This study was supported by National Institutes of Health (NIH) grant R01-HL149704 (T. Ryan). K. Kim supported by the American Heart Association grant POST903198. T. Thome supported by NIH grant F31-DK128920. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.