Expression Of PPARα/PPARβ In Neural Stem Cells During Proliferation And Differentiation

BACKGROUNDNeural stem cells are those multipotential cells in the central nervous system(CNS),which are capable of self-renewing and giving rise to fully differentiated brain cells(neuron,astrocyte and oligodendrocyte).The two characteristics of neural stem cells are self-replication and multi-directional differentiation.Neural stem cells not only contribute to the regeneration of neurons and the repair of brain tissue,but also are promising for the gene therapy in the nervous system diseases through gene modification.Those neural stem cells express ectogenic neurotransmitters,neuro-nutrition factors and metabolic enzymes,thus provide a new therapy way for many refractory diseases in nervous system.Although those cells persist during the whole adult life,their abilities to self-repair the damadged nervous tissue are relatively minor due to the limitation of absolute quantity and local microenviroment.Therefore,the ectogenous transplantation with neural stem cells is considered as one of the most prospective therapies in nervous system diseases.Peroxisome proliferation-activated receptors(PPARs)have many biological effects,including promoting adipocyte differentiation and adipogenesis,enhancing insulin sensitivity,regulating saccharometabolism homeostasis,suppressing inflammation by inhibiting inflammatory factors,affecting tumor growth and protecting the cardiovascular system.Recent studies also show that PPARs have neuroprotective effects.They could minimize the damage of neural cells in several neurodegenerative diseases,such as Alzheimers disease, Parkinson disease,cerebral ischemia and multiple sclerosis.Thus,the studies on PPARs may guide us to new potential therapy ways for those nervous diseases.METHODSDue to their properties of self-renewal and proliferation,the neural stem cells are isolated from the cerebral cortex,subependymal region and hippocampus of neonatal rats and cultured in serum-free medium supplemented with growth factors bFGF and EGF which stimulate the growth of nueral stem cells.Cell immunofluorescence,western blot and RT-PCR were employed to detect the expression levels of PPARα/PPARβprotein or mRNA respectively at different stages of NSCs. RESULTS1.The cell immunofluorescence showed that PPARα/PPARβprotein was stained as green in NSCs.Flourescence located mostly in the cell nucleus and also a little in the cytoplasm,which indicated the location of these two proteins is mainly in the cell nucleus.2.Western blot showed positive bands of PPARα/PPARβafter incubation with their antibodies respectively.With the time of NSCs differentiation,gradually weakened bands of PPARβsuggested its decreased expression during NSCs differentiation,while PPARαexpression has no significant changes shown by its similar bands.3.mRNA of PPARα/PPARβwas detected in both undifferentiated and differentiated NSCs by RT-PCR.Similar to western blot results, PPARβexpression was significantly reduced since the differentiation began.In contrast,the PPARαmRNA changed little during the differentiation process of NSCs.CONCLUSIONNeural stem cells are a kind of neural progenitor cells with the properties of self-renewal and multipotential.The successful isolation and culture of NSCs in vitro is valuable to cell transplantation in the diseases of central nervous system.PPARαand PPARβboth expressed in NSCs.Compared with undifferentiated NSCs,there was no difference of PPARαexpression level in differentiated NSCs.However,PPARβexpression decreased with the time of NSCs differentiation,indicating that PPARβmight be involved in the regulation of NSCs proliferation and differentiation.