Title

Corneal nonmyelinating Schwann cells illuminated by single-cell transcriptomics and visualized by protein biomarkers.

Document Type

Article

Publication Date

3-2021

Keywords

JGM

JAX Source

J Neurosci Res 2021 Mar; 99(3):731-749

Volume

99

Issue

3

First Page

731

Last Page

749

ISSN

1097-4547

PMID

33197966

DOI

https://doi.org/10.1002/jnr.24757

Abstract

The cornea is the most innervated tissue in the human body. Myelinated axons upon inserting into the peripheral corneal stroma lose their myelin sheaths and continue into the central cornea wrapped by only nonmyelinating corneal Schwann cells (nm-cSCs). This anatomical organization is believed to be important for central vision. Here we employed single-cell RNA sequencing (scRNA-seq), microscopy, and transgenics to characterize these nm-cSCs of the central cornea. Using principal component analysis, uniform manifold approximation and projection, and unsupervised hierarchal cell clustering of scRNA-seq data derived from central corneal cells of male rabbits, we successfully identified several clusters representing different corneal cell types, including a unique cell cluster representing nm-cSCs. To confirm protein expression of cSC genes, we performed cross-species validation, employing corneal whole-mount immunostaining with confocal microscopy in mouse corneas. The expression of several representative proteins of nm-cSCs were validated. As the proteolipid protein 1 (PLP1) gene was also expressed in nm-cSCs, we explored the Plp1-eGFP transgenic reporter mouse line to visualize cSCs. Specific and efficient eGFP expression was observed in cSCs in adult mice of different ages. Of several putative cornea-specific SC genes identified, Dickkopf-related protein 1 was shown to be present in nm-cSCs. Taken together, our findings, for the first time, identify important insights and tools toward the study nm-cSCs in isolated tissue and adult animals. We expect that our results will advance the future study of nm-cSCs in applications of nerve repair, and provide a resource for the study of corneal sensory function.

Comments

We thank Maya Yankova at the UConn Health Electron Microscopy Core facility, Susan Staurovsky from the CCAM Microscopy Facility at UConn Health, and Diane Luo and Dr. Michael Samuels from the Single Cell Biology Service at JAX for their technical assistance.

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