Secretome analysis of nerve repair mediating Schwann cells reveals Smad‐dependent trophism

Abstract

Schwann cells promote nerve regeneration by adaptation of a regenerative phenotype referred to as repair mediating Schwann cell. Down‐regulation of myelin proteins, myelin clearance, formation of Bungner's bands, and secretion of trophic factors characterize this cell type. We have previously shown that the sphingosine‐1‐phosphate receptor agonist Fingolimod/FTY720P promotes the generation of this particular Schwann cell phenotype by activation of dedifferentiation markers and concomitant release of trophic factors resulting in enhanced neurite growth of dorsal root ganglion neurons. Despite its biomedical relevance, a detailed characterization of the corresponding Schwann cell secretóme is lacking, and the impact of FTY720P on enhancing neurite growth is not defined. Here, we applied a label‐free quantitative mass spectrometry approach to characterize the secretomes derived from primary neonatal and adult rat Schwann cells in response to FTY720P. We identified a large proportion of secreted proteins with a high overlap between the neonatal and adult Schwann cells, which can be associated with biologic processes such as development, axon growth, and regeneration. Moreover, FTY720P‐treated Schwann cells release proteins downstream of Smad signaling known to support neurite growth. Our results therefore uncover a network of trophic factors involved in glial‐mediated repair of the peripheral nervous system.—Schira, J., Heinen, A., Poschmann, G., Ziegler, B., Hartung, H.‐P., Stühler, K., Küry, P. Secretome analysis of nerve repair mediating Schwann cells reveals Smad‐dependent trophism. FASEB J. 33, 4703–4715 (2019). http://www.fasebj.org

Restoration of Neurological Function Following Peripheral Nerve Trauma

“…The efficacy of fibrin in promoting axon regeneration is increased by the platelets and mesenchymal stem cells that become entrapped in the fibrin clot in the nerve gap. They act by multiple mechanisms: (1) They release neurotrophic and other factors that act directly on the axons to promote regeneration [26].…”

Secretome Analysis of Mesenchymal Stem Cell Factors Fostering Oligodendroglial Differentiation of Neural Stem Cells In Vivo

“…For mass spectrometry analysis, we used four independent biological replicates of MSCs. Confluent MSCs were washed three times with PBS in order to remove the FBS and were then incubated for another 48h in serum-free N2-medium [22,70,71] consisting of Dulbecco's modified Eagle's medium (DMEM, Gibco Cell Culture, Thermo Fisher Scientific, Darmstadt, Germany) containing 5 mg/mL insulin, 30 nM sodium selenite, 100 µM putrescine, 20 nM progesterone, and 5 µg/mL transferrin (all Sigma-Aldrich Chemie GmbH). Medium was changed again after 48 h to further exclude FBS effects, and was then incubated for another 48 h in N2 medium.…”

“…To analyze secreted proteins within this second N2 medium preparation by mass spectrometry, we performed trichloroacetic acid (TCA) precipitation as previously described [70,71]. Briefly, conditioned medium was transferred to a 50 mL tube, centrifuged at 950× g at 4 • C for 10 min, and filtered through a 0.2 µm filter (Pall Acrodisc).…”

Gliome database: a comprehensive web-based tool to access and analyze glia secretome data

“…Secretomics is a sub-field of proteomics that involves the analysis of the secretome including the liquid chromatography–mass spectrometry (LC-MS/MS) analysis, enzyme-linked immunosorbent assay (ELISA) or protein array ( 16 , 17 ). Since secretome plays a myriad of roles ranging from homeostasis to biological regulation, such as intercellular cross-talk ( 12 ), coordination of biological activity ( 18 ) and disease development ( 19 ), secretomics has been a good source for characterizing and quantifying proteins secreted by a given cell under specific experimental conditions and a powerful strategy for discovering disease biomarkers ( 20–22 ).…”

“…Currently, glial secretome has been a topic of active interest in biomarker discovery ( 17 , 23 , 24 ). Accordingly, a number of proteomics studies have identified numerous secretory proteins related to various neurological disorders ( 19 , 25–29 ). For instance, amyloid peptides and their precursors, tau proteins ( 30 ), have been identified as potential biomarkers for Alzheimer’s disease and alpha-synuclein ( 31 ) and apolipoprotein H ( 32 ) for Parkinson’s disease ( 33 ).…”