In Vitro Enfolding of Olfactory Neurites by p75 NGF Receptor Positive Ensheathing Cells from Adult Rat Olfactory Bulb

Abstract

Secondary cultures of adult rat olfactory bulb (OB) contained three different types of cell: (i) process-bearing cells; (ii) macrophage-like cells and (iii) fusiform cells. The immunohistochemical properties of process-bearing cells closely corresponded to those described for ensheathing glia in vivo. The most distinctive feature of these cells was their immunoreactivity for low affinity nerve growth factor receptor (NGFR). Process-bearing cells also shared the ultrastructural properties of ensheathing glia in vivo, as well as the ability to ensheath olfactory axons. In contrast, macrophage-like cells had the immunostaining properties of microglia, and fusiform cells were likely capillary endothelial cells. Neurites outgrowing from olfactory epithelium explants, when co-cultured with adult OB cells, grew preferentially over NGFR positive cells. Olfactory neurites exhibited NGFR immunoreactivity and were enfolded by NGFR positive cells. After ensheathment, this immunoreactivity decreased from the neurite and disappeared from the glial membrane in contact with the neurite. However, NGFR immunoreactivity was maintained in the portion of the glial membrane not involved in ensheathing. In summary, ensheathing cells in vitro retained both the ultrastructure shown in vivo and the ability to ensheath olfactory neurites. The Schwann cell-like properties of ensheathing glia, could partially explain the permissibility of adult OB to axonal growth.

Olfactory ensheathing cells transplanted in lesioned spinal cord prevent loss of spinal cord parenchyma and promote functional recovery

“…First, in vitro OECs express nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), glia cell line-derived neurotrophic factor (GDNF), and their receptors (Woodhall (Boruch et al, 2001) and p-75 low-affinity NGF receptor (Ramón-Cueto et al, 1993). It is well known that all these neurotrophic factors promote sprouting and regeneration of central axons.…”

The Immunohistochemical Characterization of Human Fetal Olfactory Bulb and Olfactory Ensheathing Cells in Culture as a Source for Clinical CNS Restoration

“…In fact, the OECs transplantation in clinic is a mixture of olfactory bulb cells, even though, the purity of OEC cultures, generated by a number of different procedures, is most often defined by the percentage of cells that express the P75NTR (Ramon-Cueto et al, 1993). This phenotypic marker is, however, common to both OECs and Schwann cells in vitro (Kawaja et al, 2009).…”

Migratory properties of cultured olfactory ensheathing cells by single-cell migration assay

“…One subpopulation is known as the Schwann cell-like OECs, which have a long fusiform bipolar morphology; the other is known as the astrocytelike OECs, which have a flat sheet-like morphology. Interestingly, several studies have shown that Schwann cell-like OECs are more effective in promoting axonal regeneration than astrocyte-like OECs in vitro and in vivo [11,[28][29][30]. Transplanted OECs from the lamina propria and olfactory bulb, which display differential integration and migration, promote differential axonal sprouting in the lesioned spinal cord [31].…”