Distinct endothelial gene responses to acute exercise in skeletal muscle.

Acute exercise causes a short-term stress, activating immediate gene expression responses. These responses are essential for cellular adaptation and resilience. Endothelial cells, positioned throughout the vasculature, play a central role in sensing and responding to these stress signals. As dynamic regulators of vascular tone, nutrient delivery, and cellular communication, endothelial cells are key integrators of metabolic adaptation. They coordinate intra- and interorgan communication through the release of signaling molecules, shaping systemic responses to exercise. Despite their importance, the endothelial cell-specific transcriptional response to exercise remains poorly understood. To interrogate the transcriptional response to exercise in endothelial cells, we used NuTRAP (Nuclear Tagging and Translating Ribosome Affinity Purification) mouse technology that expresses EGFP/L10a under control of the vascular endothelial-cadherin promoter (NuTRAP^EC). Following a single bout of acute exercise, ribosome-associated mRNA was isolated from endothelial cells from gastrocnemius of both exercised and sedentary animals. RNA sequencing confirmed endothelial cell-specific enrichment and revealed robust changes in gene expression. Exercise induced canonical early response genes (Nr4a2, Sik1, and Slc25a25) and activated pathways related to angiogenesis, oxidative stress, stress kinase signaling, vascular remodeling, and metabolic stress signaling. For context, we analyzed skeletal muscle fiber responses using NuTRAP mice driven by the human α-skeletal actin (NuTRAP^SMF) mice. Although some genes overlapped, skeletal muscle fiber-enriched pathways included hypoxia response and muscle development. These findings reveal a distinct microvascular endothelial transcriptional signature in skeletal muscle tissue in response to acute exercise, providing insight into the cell-type-specific mechanisms that underlie vascular adaptation and intercellular communication in response to physiological stressors like exercise.NEW & NOTEWORTHY This study profiles the endothelial-specific transcriptional response to acute exercise at cell-type resolution. Comparative analysis with skeletal muscle fibers revealed distinct gene expression and upstream regulators. Key findings include endothelial-specific expression of exerkines, metabolic genes, and nitric oxide signaling. These results uncover a molecular basis for endothelial adaptation to exercise and suggest a potential role in mediating systemic exercise benefits.