Korean J Physiol Pharmacol.  2004 Oct;8(5):253-257.

Double-stranded RNA Induces Inflammatory Gene Expression in Schwann Cells: Implication in the Wallerian Degeneration

• Lee H
• Park C
• Choi SY
• Oh SB
• Park K
• Kim JS
• Lee SJ

Abstract

Schwann cells play an important role in peripheral nerve regeneration. Upon neuronal injury, activated Schwann cells clean up the myelin debris by phagocytosis, and promote neuronal survival and axon outgrowth by secreting various neurotrophic factors. However, it is unclear how the nerve injury induces Schwann cell activation. Recently, it was reported that certain cytoplasmic molecules, which are secreted by cells undergoing necrotic cell death, induce immune cell activation via the toll-like receptors (TLRs). This suggests that the TLRs expressed on Schwann cells may recognize nerve damage by binding to the endogenous ligands secreted by the damaged nerve, thereby inducing Schwann cell activation. Accordingly, this study was undertaken to examine the expression and the function of the TLRs on primary Schwann cells and iSC, a rat Schwann cell line. The transcripts of TLR2, 3, 4, and 9 were detected on the primary Schwann cells as well as on iSC. The stimulation of iSC with poly (I: C), a synthetic ligand for the TLR3, induced the expression of TNF-alpha and RANTES. In addition, poly (I: C) stimulation induced the iNOS expression and nitric oxide secretion in iSC. These results suggest that the TLRs may be involved in the inflammatory activation of Schwann cells, which is observed during Wallerian degeneration after a peripheral nerve injury.

Keyword

Schwann cells; Toll-like receptor; iNOS; RANTES; TNF-alpha; iSC

MeSH Terms

Animals
Axons
Cell Death
Cell Line
Chemokine CCL5
Cytoplasm
Gene Expression*
Ligands
Myelin Sheath
Nerve Growth Factors
Neurons
Nitric Oxide
Peripheral Nerve Injuries
Peripheral Nerves
Phagocytosis
Rats
Regeneration
RNA, Double-Stranded*
Schwann Cells*
Toll-Like Receptors
Tumor Necrosis Factor-alpha
Wallerian Degeneration*
Chemokine CCL5
Ligands
Nerve Growth Factors
Nitric Oxide
RNA, Double-Stranded
Toll-Like Receptors
Tumor Necrosis Factor-alpha