Shotgun Proteomics and Network Analysis between Plasma Membrane and Extracellular Matrix Proteins from Rat Olfactory Ensheathing Cells

Abstract

Olfactory ensheathing cells (OECs) are a special type of glial cells that have characteristics of both astrocytes and Schwann cells. Evidence suggests that the regenerative capacity of OECs is induced by soluble, secreted factors that influence their microenvironment. These factors may regulate OECs self-renewal and/or induce their capacity to augment spinal cord regeneration. Profiling of plasma membrane and extracellular matrix through a high-throughput expression proteomics approach was undertaken to identify plasma membrane and extracellular matrix proteins of OECs under serum-free conditions. 1D-shotgun proteomics followed with gene ontology (GO) analysis was used to screen proteins from primary culture rat OECs. Four hundred and seventy nonredundant plasma membrane proteins and 168 extracellular matrix proteins were identified, the majority of which were never before reported to be produced by OECs. Furthermore, plasma membrane and extracellular proteins were classified based on their protein-protein interaction predicted by STRING quantitatively integrates interaction data. The proteomic profiling of the OECs plasma membrane proteins and their connection with the secretome in serum-free culture conditions provides new insights into the nature of their in vivo microenvironmental niche. Proteomic analysis for the discovery of clinical biomarkers of OECs mechanism warrants further study.