Neuregulin-1 type III knockout mice exhibit delayed migration of Schwann cell precursors
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Authors: Miyamoto, Yuki; Torii, Tomohiro; Tanoue, Akito; Kawahara, Kazuko; Arai, Miyuki; Tsumura, Hideki; Ogata, Toru; Nagao, Motoshi; Terada, Nobuo; Yamamoto, Masahiro; Takashima, Shou; Yamauchi, Junji
Abstract
In an embryonic developmental stage of the peripheral nervous system (PNS), Schwann cell precursors migrate along neuronal axons to their final destinations. After birth, they eventually wrap around individual axons to form myelin sheaths, which insulate axons to increase the nerve conduction velocity. Some growth factors and adhesion molecules are known to control these developmental stages from in the fish to in the mammal. Neuregulin-1 (NRG1), which is composed of many alternative splicing variants, is such a growth factor. Among these variants, the type III isoform of NRG1, interacting with ErbB2 and ErbB3 receptors on Schwann cells, plays an essential role in myelination in the fish and the mammal. NRG1 type III is also known to promote migration of fish Schwann cell precursors; however, it still remains to be clarified whether mammalian type III isoform does it. We have therefore generated type III isoform-specific knockout mice in inbred strain. The mice result in delayed migration of the precursors from the dorsal to ventral root via a peripheral ganglion, comparing littermate controls. Similar results are observed in an in vitro migration assay using reaggregated Schwann cell precursors. Furthermore, the knockout mice exhibit reduced myelin thickness, consistent with the established role of NRG1 type III in myelination. These results indicate that in mice, NRG1 type III plays a key role not only in myelination but also in migration. (C) 2017 Elsevier Inc. All rights reserved.
NRG1 signalling regulates the establishment of Sertoli cell stock in the mouse testis
MOLECULAR AND CELLULAR ENDOCRINOLOGY
Authors: Gregoire, Elodie P.; Stevant, Isabelle; Chassot, Anne-Amandine; Martin, Luc; Lachambre, Simon; Mondin, Magali; de Rooij, Dirk G.; Nef, Serge; Chaboissier, Marie-Christine
Abstract
Testis differentiation requires high levels of proliferation of progenitor cells that give rise to two cell lineages forming the testis, the Sertoli and the Leydig cells. Hence defective cell cycling leads to testicular dysgenesis that has profound effects on androgen production and fertility. The growth factor NRG1 has been implicated in adult Leydig cell proliferation, but a potential function in the fetal testis has not been analysed to date. Here we show that Nrg1 and its receptors ErbB2/3 are already expressed in early gonadal development. Using tissue-specific deletion, we further demonstrate that Nrg1 is required in a dose-dependent manner to induce proliferation of Sertoli progenitor cells and then differentiated Sertoli cells. As a result of reduced numbers of Sertoli cells, Nrg1 knockout mice display a delay in testis differentiation and defects in sex cord partitioning. Taken together Nrg1 signalling is essential for the establishment of the stock of Sertoli cells and thus required to prevent testicular hypoplasia.