Differential gene expression in motor and sensory Schwann cells in the rat femoral nerve

Abstract

Phenotypic differences in Schwann cells (SCs) may help guide axonal regeneration down motor or sensory specific pathways following peripheral nerve injury. The goal of this study was to identify phenotypic markers for SCs harvested from the cutaneous (sensory) and quadriceps (motor) branches of the rat femoral nerve and to study the effects of expansion culture on the expression patterns of these motor or sensory phenotypic markers. RNA was extracted from SCs harvested from the motor and sensory branches of the rat femoral nerve and analyzed using Affymetrix Gene Chips© (Rat Genome 230 v2.0 Array A). Genes that were upregulated in motor SCs compared to the sensory SCs or vice versa were identified, and the results were verified for a subset of genes using quantitative real time polymerase chain reaction (qRT-PCR). The expression levels of the “phenotype-specific” genes were then evaluated in SC expansion cultures at various timepoints over 30 days by qRT-PCR to determine the effect of expansion on SC phenotype. Expression levels of the phenotype-specific genes were significantly altered after expansion culture for both the motor and sensory markers compared to fresh nerve tissue. These results indicate that both motor and sensory SC gene expression patterns are disrupted during expansion in vitro and may affect the ability of SCs to express phenotype specific genes after transplantation.

Glial cell line-derived neurotrophic factor promotes increased phenotypic marker expression in femoral sensory and motor-derived Schwann cell cultures

“…Using the QuantiTect® SYBR® Green PCR Mastermix (Qiagen) in combination with gene-specific QuantiTect® primers, qPCR was performed with an Applied Biosystems 7000 Real-Time PCR thermocycler. The genes studied included S100β (differentiated SC marker), nestin (undifferentiated SC marker) (Brockes et al, 1979), motor-specific markers, vascular endothelial cell growth factor (VEGF) and protein kinase C iota (PRKCi), and sensory-specific markers, brain derived neurotrophic factor (BDNF) and myelin basic protein (MBP) (Hoke et al, 2006; Jesuraj et al, 2012). Primers (Table 2) were added to the cDNA for the motor and sensory-derived SCs.…”

“…Previously, our lab and others have shown that SCs derived from the motor and sensory branches of rat femoral nerve have different phenotypic profiles, which are dysregulated after SC expansion in culture (Hoke et al, 2006; Jesuraj et al, 2012). We hypothesized that exogenous GDNF would promote differentiation of SCs after expansion culture and restore expression of SC phenotypic markers.…”

Extrinsic cellular and molecular mediators of peripheral axonal regeneration

“…This may be partially attributed to the fact that Schwann cells express distinct motor and sensory phenotypes (Jesuraj et al 2012) and consequently express differential patterns of neurotrophic factors and growth factors after injury. Motor Schwann cells display up-regulation of, e.g., BDNF, pleiotrophin (PTN) and the p75 NTR -receptor (Jin et al 2009;Höke et al 2006), whereas the sensory Schwann cells show lesioninduced expression of a broader spectrum of neurotrophins, presumably reflecting the heterogeneity of sensory DRG neurons (Höke et al 2006).…”

Update in facial nerve paralysis

“…After nerve injury, Schwann cells proliferate and organize themselves to help guide regenerating axons to their distal targets [13]. Gene expression and phenotype studies of Schwann cells suggest differences between Schwann cells from sensory versus motor nerves [14]. Schwann cells dedifferentiate to a permissive state of growth after nerve injury, whereas adult Schwann cells lack the growth permissive phenotype [10].…”