Effects of GDF5 overexpression on embryonic rat dopaminergic neurones in vitro and in vivo
JOURNAL OF NEURAL TRANSMISSION
Authors: O'Sullivan, David B.; Harrison, Patrick T.; Sullivan, Aideen M.
Abstract
Transplantation of embryonic dopaminergic neurones has shown promise for the treatment of Parkinson's disease (PD), but this approach is limited by the poor survival of the transplanted cells. Exogenous dopaminergic neurotrophic factors such as growth/differentiation factor 5 (GDF5) have been found to enhance the survival of transplanted dopaminergic neurones. However, this approach is limited by the rapid degradation of such factors in vivo; thus, methods for long-term delivery of these factors are under investigation. The present study shows, using optimised lipid-mediated transfection procedures, that overexpression of GDF5 significantly improves the survival of dopaminergic neurones in cultures of embryonic day (E) 13 rat ventral mesencephalon (VM) and protects them against 6-hydroxydopamine (6-OHDA)-induced toxicity. In another experiment, E13 VM cells were transfected with GDF5 after 1 day in vitro (DIV), then transplanted into 6-OHDA-lesioned adult rat striata after 2 DIV. The survival of these E13 VM dopaminergic neurones after transfection and transplantation was as least as high as that of freshly dissected E14 VM dopaminergic neurones, demonstrating that transfection was not detrimental to these cells. Furthermore, GDF5-overexpressing E13 VM transplants significantly reduced amphetamine-induced rotational asymmetry in the lesioned rats. This study shows that lipid-mediated transfection in vitro prior to transplantation is a valid approach for the introduction of neurotrophic proteins such as GDF5, as well as lending further support to the potential use of GDF5 in neuroprotective therapy for PD.
Nucleus Pulposus Explant Culture Model
JOURNAL OF ORTHOPAEDIC RESEARCH
Authors: Feng, Gang; Wan, Yuqing; Shen, Francis H.; Li, Xudong
Abstract
Many of the therapeutic interventions for intervertebral disc degeneration attempt to repopulate the nucleus pulposus (NP) tissue; however, NP cells are heterogeneous and not well characterized. To address this, we have investigated the morphology, extracellular gene and protein expression, and apoptosis changes in NP explants cultured in vitro with or without chondrogenic reagents for different periods. We also compared the susceptibility of the explants to different treatments by comparing: treatment of NP explants with GDF5 protein, transfection of NP explants with GDF5 plasmid, and inflection of Nil explants with GDF5 adenovirus vector. We found that expression levels of two of the major extracellular proteins found in NP tissue, that is, collagen II and aggrecan, could be maintained in an NP explant culture model with a chondrogenic medium up to 7 days, and were significantly higher than that of fresh NP tissue after 14 days of culture in vitro, whether or not chondrogenic medium was used. In addition, the NP explant responded to treatment with growth factor, and could be infected by virus and transfected by plasmid for further evaluation of growth factor gene therapy. NP explant culture could therefore provide an easy in vitro culture model to characterize NP cells and evaluate potential therapeutic reagents. (C) 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:814-819, 2009