Dorsal root ganglion progenitors differentiate to gamma-aminobutyric acid-and choline acetyltransferase-positive neurons

This study examined the isolation and differentiation of dorsal root ganglion progenitor cells for therapeutic use in neurodegenerative diseases. Rat embryonic dorsal root ganglia progenitors were isolated and purified using the differential adhesion method combined with cytosine arabinoside treatment. After culture in serum-free medium supplemented with B27, basic fibroblast growth factor and epidermal growth factor, these cells remained viable and survived for more than 18 months in vitro. Most cells differentiated to neurons that were immunoreactive for gamma-aminobutyric acid and choline acetyltransferase as detected by immunohistochemical staining. In addition, nerve growth factor and neurotrophic tyrosine kinase receptor expression were also observed in dorsal root ganglion progenitors and differentiated cells. K252a, an inhibitor that blocks nerve growth factor-induced signaling, inhibited cell survival, suggesting the possible existence of a nerve growth factor autocrine loop in these proliferating cells.

Ginseng-Derived Panaxadiol Saponins Promote Hematopoiesis Recovery in Cyclophosphamide-Induced Myelosuppressive Mice:Potential Novel Treatment of Chemotherapy-Induced Cytopenias

Objective：To investigate the potential efficacy of panaxadiol saponins component（PDS-C）,a biologically active fraction isolated from total ginsenosides,to reverse chemotherapy-induced myelosuppression and pancytopenia caused by cyclophamide（CTX）.Methods：Mice with myelosuppression induced by CTX were treated with PDS-C at a low-（20 mg/kg）,moderate-（40 mg/kg）,or high-dose（80 mg/kg） for 7 consecutive days.The level of peripheral white blood cell（WBC）,neutrophil（NEU） and platelet（PLT） were measured,the histopathology and colony formation were observed,the protein kinase and transcription factors in hematopoietic cells were determined by immunohistochemical staining and Western blot.Results：In response to PDS-C therapy,the peripheral WBC,NEU and PLT counts of CTX-induced myelosuppressed mice were significantly increased in a dose-dependent manner.Similarly,bone marrow histopathology examination showed reversal of CTX-induced myelosuppression with increase in overall bone marrow cellularity and the number of hematopoietic cells（P〈0.01）.PDS-C also promoted proliferation of granulocytic and megakaryocyte progenitor cells in CTX-treated mice,as evidenced by significantly increase in colony formation units-granulocytes/monocytes and-megakaryocytes（P〈0.01）.The enhancement of hematopoiesis by PDS-C appears to be mediated by an intracellular signaling pathway,this was evidenced by the up-regulation of phosphorylated mitogen-activated protein kinase（p-MEK） and extracellular signal-regulated kinases（p-ERK）,and receptor tyrosine kinase（C-kit） and globin transcription factor 1（GATA-1） in hematopoietic cells of CTX-treated mice（P〈0.05）.Conclusions：PDS-C possesses hematopoietic growth factor-like activities that promote proliferation and also possibly differentiation of hematopoietic progenitor cells in myelosuppressed mice,probably mediated by a mechanism involving MEK and ERK protein kinases,and C-kit and GATA-1 transcription factors.PDS-C may potentially be a novel treatment of myelosuppression and pancytopenia caused by chemotherapy.