Mesenchymal Cell Precursors of Peritubular Smooth Muscle Cells of the Mouse Testis Can Be Identified by the Presence of the p75 Neurotrophin Receptor1

Abstract

In the mouse embryo, at approximately 11.5 days postcoitum (dpc), cells migrate from the mesonephros into the developing testis to contribute to the somatic population of the interstitial compartment (i.e., peritubular myoid cells, Leydig cells, and endothelial cells). Studies from this laboratory have shown that the interstitial population of mesenchymal cells in fetal and newborn mouse testis express the p75 neurotrophin receptor (p75NTR, formerly known as the low-affinity nerve growth factor receptor); part of the cell population progressively congregates around testis cords, later to be replaced by contractile peritubular myoid cells, which express smooth muscle cell markers. In the present study, we show that the migrating cells and the p75NTR-expressing cells are the same population. We also show that the neurotrophin receptor is a useful endogenous marker to follow cell migration within the urogenital ridge and to identify and isolate mesenchymal precursors of myoid cells. A time-course immunolocalization study of the location of p75NTR-bearing cells within the urogenital ridge of mouse embryos between 10.5 and 12.5 dpc showed that the interstitium of the fetal testis was progressively occupied by p75NTR+ cells. The progressive increase of p75NTR expression within the developing testis was confirmed by immunoblot analysis of proteins isolated from the fetal gonads. Organ cultures of isolated testes or testis-mesonephros grafts confirmed that p75NTR+ cells do not appear in the testis unless a mesonephros is attached to it. Cells bearing the p75NTR receptor, purified from 12.5-dpc male mouse mesonephroi by immunomagnetic sorting, were able to differentiate in vitro into myoid cells. Immunofluorescence analysis of postnatal testis sections confirmed the presence around the tubules of cells coexpressing p75NTR and alpha-smooth muscle actin. The ability to identify and purify precursors of myoid cells may be of considerable help for studying the mechanisms regulating their differentiation.

Anti-L-NGFR and -CD34 Monoclonal Antibodies Identify Multipotent Mesenchymal Stem Cells in Human Adipose Tissue

“…Altogether, our data suggest that the selection with anti-L-NGFR MoAb allows us to obtain a more homogeneous and primitive population: the almost total co-expression of CD34, the expression of the stem markers CD117 and CD105, and the higher proliferative, clonogenic, and differentiative potential, in particular at early passages, seem to support this observation. The role of L-NGFR in MSCs is still unclear, although its expression has been described in BM and in other tissues [ 34 , 57 ] and it has been shown to be involved in several functions including morphogenesis [58][59][60][61], growth factor presentation [ 62 ], and apoptosis in response to NGF stimulation [ 63 ].…”

Expression and role of PDGF-BB and PDGFR-β during testis morphogenesis in the mouse embryo

“…As our previous studies (Campagnolo et al, 2001) had shown that mesenchymal cells that migrate from the mesonephros into the developing testis can be identified by the presence on their surface of the p75 neurotrophin receptor, we explored the possibility that these cells might be bearing the PDGFR-β as well. Cells immunomagnetically sorted for the presence of the p75NTR were assayed for the presence of the PDGFR-β, and the results showed that essentially all of the p75NTR positive cells were also positive for PDGFR-β.…”

“…Immunomagnetic cell sorting of mesonephric cell suspension Mesonephric cells bearing the p75 neurotrophin receptor were immunomagnetically selected as previously described (Campagnolo et al, 2001). Briefly, mesonephroi isolated from 12.5 dpc male mice embryos were incubated in trypsin-EDTA, followed by collagenaseDNAse digestion.…”

“…We have previously shown that mesenchymal cells that migrate from the mesonephros into the testis can be identified by the presence on their surface of the p75 neurotrophin receptor, and can be isolated as an essentially pure (>96%) cell population by immunomagnetically sorting the total mesonephric cell suspension with anti-p75NTR antibody (Campagnolo et al, 2001). Because the PDGFβ receptor has been shown to play a role in the migration and proliferation of cells of mesenchymal origin, we have investigated whether this receptor molecule is expressed by p75NTR(+) cells.…”

“…As previous results from this laboratory had shown that such migrating cells can be identified by the presence on their surface of the p75 neurotrophin receptor (p75NTR, formerly known as the low-affinity nerve growth factor (NGF) receptor) (Russo et al, 1999;Campagnolo et al, 2001), the experiments on isolated cells reported in the present paper have been performed on mesonephric cells that had been isolated by immunomagnetic selection with anti-p75NTR antibodies.…”