Gene profiling and bioinformatic analysis of Schwann cell embryonic development and myelination

Abstract

To elucidate the molecular mechanisms involved in Schwann cell development, we profiled gene expression in the developing and injured rat sciatic nerve. The genes that showed significant changes in expression in developing and dedifferentiated nerve were validated with RT-PCR, in situ hybridisation, Western blot and immunofluorescence. A comprehensive approach to annotating micro-array probes and their associated transcripts was performed using Biopendium, a database of sequence and structural annotation. This approach significantly increased the number of genes for which a functional insight could be found. The analysis implicates agrin and two members of the collapsin response-mediated protein (CRMP) family in the switch from precursors to Schwann cells, and synuclein-1 and alphaB-crystallin in peripheral nerve myelination. We also identified a group of genes typically related to chondrogenesis and cartilage/bone development, including type II collagen, that were expressed in a manner similar to that of myelin-associated genes. The comprehensive function annotation also identified, among the genes regulated during nerve development or after nerve injury, proteins belonging to high-interest families, such as cytokines and kinases, and should therefore provide a uniquely valuable resource for future research.

The Atypical Guanine-Nucleotide Exchange Factor, Dock7, Negatively Regulates Schwann Cell Differentiation and Myelination

“…Schwann cells were plated for experiments on collagen (type I)-coated culture dishes or wells. For morphological differentiation experiments, rat Schwann cells were cultured, first in Sato medium (Bottenstein and Sato, 1979) for 1 d, and then in Sato medium containing 0, 0.3, or 1 mM dibutyryl cAMP for an additional 2 d (Sobue et al, 1986;D'Antonio et al, 2006;Monje et al, 2010). For a proliferation assay, Schwann cells were seeded at 1 ϫ 10 5 cells/3.5 cm dish, cultured in the presence of 10 ng/ml neuregulin-1 (R&D Systems) and 5 M forskolin for 0 -48 h, and counted using a hemocytometer.…”

“…processes, accompanied by the expression of myelin marker proteins such as MBP and MPZ (Sobue et al, 1986;D'Antonio et al, 2006;Monje et al, 2010). Differentiated Schwann cells often form a myelin web-like structure with fenestrated cytoplasmic sheets (Sobue et al, 1986;D'Antonio et al, 2006;Monje et al, 2010; see Fig.…”

Negative regulation of myelination: Relevance for development, injury, and demyelinating disease

“…In the case of myelinating cells this involves downregulation of a large number of genes related to myelination (reviewed in Jessen and Mirsky, 2005;Mirsky et al, 2008;Scherer and Salzer, 2001). This includes enzymes that provide for cholesterol synthesis, structural proteins such as P 0 , myelin basic protein (MBP), and membrane associated proteins such as myelin associated glycoprotein (MAG) and periaxin (Buchstaller et al, 2004;D'Antonio et al, 2006;Leblanc et al, 2005;Nagarajan et al, 2001Nagarajan et al, , 2002Verheijen et al, 2003). This switch-off is accompanied by the activation of another group of molecules, most of which are normally found on immature cells prior to myelination.…”

“…The different outcome of the co-culture experiments on the one hand and the direct knock-down of NT3 in vivo on myelination is paralleled in experiments in which the effects of transforming growth factor (TGF)b were examined in co-culture or in vivo. TGFb inhibits myelination in co-cultures (Einheber et al, 1995), whereas knockout of TGFb signaling specifically in Schwann cells has no effects on myelination but reduces Schwann cell proliferation and death in developing nerves (D'Antonio et al, 2006). This emphasizes the importance of timing and the context in which a particular molecule exerts its effects.…”

TGFβ Type II Receptor Signaling Controls Schwann Cell Death and Proliferation in Developing Nerves

“…RNA isolation, reverse transcriptase reaction, and reverse transcription (RT)-PCR experiments were performed as described previously (D'Antonio et al, 2006). Primers for periaxin were as described by Parkinson et al (2003).…”