Expression of GAP-43 in fibroblast cell lines influences the orientation of cell division

Neuroregeneration and functional recovery after stroke: advancing neural stem cell therapy toward clinical application

Stroke is a main cause of death and disability worldwide. The ability of the brain to self-repair in the acute and chronic phases after stroke is minimal; however, promising stem cell-based interventions are emerging that may give substantial and possibly complete recovery of brain function after stroke. Many animal models and clinical trials have demonstrated that neural stem cells (NSCs) in the central nervous system can orchestrate neurological repair through nerve regeneration, neuron polarization, axon pruning, neurite outgrowth, repair of myelin, and remodeling of the microenvironment and brain networks. Compared with other types of stem cells, NSCs have unique advantages in cell replacement, paracrine action, inflammatory regulation and neuroprotection. Our review summarizes NSC origins, characteristics, therapeutic mechanisms and repair processes, then highlights current research findings and clinical evidence for NSC therapy. These results may be helpful to inform the direction of future stroke research and to guide clinical decision-making.

GAP-43 is involved in the orientation of cell division by interacting with GΑI during neurogenesis

Purpose: Recent studies have shown that growth-associated protein-43 (GAP-43) may influence the mitotic-spindle orientation of Madin-Darby Canine Kidney (MDCK) cells through interacting with G proteins in vitro. However, whether GAP-43 interacts with the G proteins under the influence of mitotic spindle positioning related to the orientation of cell division during neurogenesis remains unclear. In order to explore the molecular mechanism in vivo, the GAP-43 transgenic mice were produced and the angles of cell division in the ventricular zone (VZ) during neurogenesis (embryonic period between 13.5 and 17.5 days) were measured in both transgenic mice and wild type mice by spindle angle analysis.Materials and methods: The interaction of GAP-43 and Gαi was detected by co-immunoprecipitation (co-IP), whereas the localization of GAP-43 was determined by immunofluorescence.Results: The results obtained using co-IP and immunofluorescence showed that GAP-43 is localized on the cell membrane and interacts with Gαi. This interaction dramatically induced a significant increase in the proportion of horizontally and intermediately dividing cells during the embryonic period of 13.5 days in the transgenic mouse brain, as observed by spindle angle analysis.Conclusions: It can be concluded that GAP-43 is involved in the orientation of cell division by interacting with Gαi, and that this may be an important mechanism for neurogenesis in the mammalian brain.

The influence of GAP-43 on orientation of cell division through G proteins

Recent studies have shown that GAP-43 is highly expressed in horizontally dividing neural progenitor cells, and G protein complex are required for proper mitotic-spindle orientation of those progenitors in the mammalian developing cortex. In order to verify the hypothesis that GAP-43 may influence the orientation of cell division through interacting with G proteins during neurogenesis, the GAP-43 RNA from adult C57 mouse was cloned into the pEGFP-N1 vector, which was then transfected into Madin-Darby Canine Kidney (MDCK) cells cultured in a three-dimensional (3D) cell culture system. The interaction of GAP-43 with Gαi was detected by co-immunoprecipitation (co-IP), while cystogenesis of 3D morphogenesis of MDCK cells and expression of GAP-43 and Gαi were determined by immunofluorescence and Western blotting. The results showed are as follows: After being transfected by pEGFP-N1-GAP-43, GAP-43 was localized on the cell membrane and co-localized with Gαi, and this dramatically induced a defective cystogenesis in 3D morphogenesis of MDCK cells. The functional interaction between GAP-43 and Gαi proteins was proven by the co-IP assay. It can be considered from the results that the GAP-43 is involved in the orientation of cell division by interacting with Gαi and this should be an important mechanism for neurogenesis in the mammalian brain.