Dynamic changes of gangliosides expression during the differentiation of embryonic and mesenchymal stem cells into neural cells.

Stem cells are used for the investigation of developmental processes at both cellular and organism levels and offer tremendous potentials for clinical applications as an unlimited source for transplantation. Gangliosides, sialic acid-conjugated glycosphingolipids, play important regulatory roles in cell proliferation and differentiation. However, their expression patterns in stem cells and during neuronal differentiation are not known. Here, we investigated expression of gangliosides during the growth of mouse embryonic stem cells (mESCs), mesenchymal stem cells (MSCs) and differentiated neuronal cells by using high-performance thin-layer chromatography (HPTLC). Monosialoganglioside 1 (GM1) was expressed in mESCs and MSCs, while GM3 and GD3 were expressed in embryonic bodies. In the 9-day old differentiated neuronal cells from mESCs cells and MSCs, GM1 and GT1b were expressed. Results from immunostaining were consistent with those observed by HPTLC assay. These suggest that gangliosides are specifically expressed according to differentiation of mESCs and MSCs into neuronal cells and expressional difference of gangliosides may be a useful marker to identify differentiation of mESCs and MSCs into neuronal cells.

Differential expression patterns of gangliosides in the ischemic cerebral cortex produced by middle cerebral artery occlusion.

Neuronal damage subsequent to transient cerebral ischemia is a multifactorial process involving several overlapping mechanisms. Gangliosides, sialic acid-conjugated glycosphingolipids, reduce the severity of acute brain damage in vitro. However their in vivo effects on the cerebral cortex damaged by ischemic infarct are unknown. To assess the possible protective role of gangliosides we examined their expression in the cerebral cortex damaged by ischemic infarct in the rat. Ischemia was induced by middle cerebral artery (MCA) occlusion, and the resulting damage was observed by staining with 2, 3, 5-triphenylterazolium chloride (TTC). High-performance thin-layer chromatography (HPTLC) showed that gangliosides GM3 and GM1 increased in the damaged cerebral cortex, and immunofluorescence microscopy also revealed a significant change in expression of GM1. In addition, in situ hybridization demonstrated an increase in the mRNA for ganglioside GM3 synthase. These results suggest that gangliosides GM1 and GM3 may be synthesized in vivo to protect the cerebral cortex from ischemic damage.