TrkAWT and TrkAF592A animals at 14 d post-operative tendon injury for scRNA-Seq.

Peripheral afferent neurons terminate at the surfaces of tendons, yet their role after injury beyond nociceptive functions remain unclear. Using transgenic animal models, sensory neurons were found to sprout after Achilles tendon injury in domains of Nerve growth factor (NGF) expression. Conditional deletion of Ngf in either myeloid or mesenchymal cell types led to tendon repair defects – findings phenocopied by inactivation of TrkA (Tropomyosin receptor kinase A) using a knockin mouse model. We sought to identify the signals modulated with neural TrkA inhibition. A combination of single cell and spatial transcriptomic analysis was performed on the Achilles injury site of TrkAF592A animals and compared them to TrkAWT. Overall design: The injury site was dissected from TrkAWT (CONTROL) and TrkAF592A (INMPP1) animals at 14 d post-operative for scRNA-Seq. Pooled N=3 mice per genotype