Abstract
Peripheral nerves provide a supportive growth environment for developing and regenerating axons and are essential for maintenance and repair of many non-neural tissues. This capacity has largely been ascribed to paracrine factors secreted by nerve-resident Schwann cells. Here, we used single-cell transcriptional profiling to identify ligands made by different injured rodent nerve cell types and have combined this with cell-surface mass spectrometry to computationally model potential paracrine interactions with peripheral neurons. These analyses show that peripheral nerves make many ligands predicted to act on peripheral and CNS neurons, including known and previously uncharacterized ligands. While Schwann cells are an important ligand source within injured nerves, more than half of the predicted ligands are made by nerve-resident mesenchymal cells, including the endoneurial cells most closely associated with peripheral axons. At least three of these mesenchymal ligands, ANGPT1, CCL11, and VEGFC, promote growth when locally applied on sympathetic axons. These data therefore identify an unexpected paracrine role for nerve mesenchymal cells and suggest that multiple cell types contribute to creating a highly pro-growth environment for peripheral axons.
- growth factor
- nerve
- paracrine interactions
- regeneration
- scRNA-seq
- peripheral neurons
- neuronal growth
- Schwann cell
- mesenchymal cell
Footnotes
The authors declare no competing financial interests.
This work was funded by Canadian Institutes of Health Research (CIHR) and the Canada First Research Excellence Fund “Medicine by Design” (F.D.M. and D.R.K.). J.S.T. and M.A.S. were funded by CIHR fellowships, M.J.C. by a CIHR studentship, and S.A.Y. by a Lap-Chee Tsui Restracomp fellowship during the course of these studies.
S.A. Yuzwa’s present address: Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
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