The Expression Of Protein 4.1 Family In Different Mouse Brain-derived Nervous Stem Cells And Cells Differentiated From Them

Background and ObjectivesProtein 4.1 family (the band 4.1 of erythrocyte membrane proteins after SDS-PAGE) is the fundamental component of erythrocyte membrane skeleton, which constructs on the basis of spectrin and contains the members of 4.1R, 4.1G, 4.1N and 4.1B. Researches demonstrated that protein 4.1 family plays an important role in maintaining cell skeletons, cell-cell and cell-matrix connections and interacts with intracellular messengers and enzymes. Protein 4.1 family not only exerts its roles in maintaining normal cell shape and physiological characteristics via its interaction with actin, spectrin and the intracellular regions of membrane proteins, and also plays an important role in cell mitosis and the formation of neurons. Alzheimer's disease (AD) is a kind of neurodegenerative disease, which is characterized by the formation of senile plaques (SP) and neurofibril tangles (NFT) in the cerebral cortices and hippocampus, diffused brain atrophy and reduction of neurons in the cerebral cortices and hippocampus. The principal component of SP is Aβ, which derives from amyloid precuser protein(APP). Thus we investigated the expression of protein 4.1 family in mouse brain-derived nervous stem cells and cells differentiated from them, in order to unveil the role of this protein family in nervous development and the pathological mechanisms of neurodegenerative diseases such as AD.Materials and Methods We isolated and cultured the brain nervous stem cells of new-born normal C57 mice and APP transgenic mice (the transgenic model of AD). The identification of nervous stem cells was identified by the expression of nestin. We then induced the stem cells into neurons. The expression of proteins 4.1R, 4.1G, 4.1N and 4.1B in different differentiation stages was examined by immunocytochemistry and their mRNA expression was examined by semi-quantitative reverse transcription polymerase chain reaction.Results(1) Cells isolated form new-born mouse brains developed large amounts of suspending neurospheres. They also could be sub cultured in vitro. The WST-1 testing showed that these neurospheres might be amplified in vitro (P<0.05). These neurospheres were nestin-positive by immunocytochemistrical staining and could differentiate into cells which expressed neuron- and astrocyte-specific antigens.(2) In immunocytochemistrical analysis, the expression of four members of protein 4.1 family on the 15th day of differentiation were all increased compared with that on the 5th and 10th day of differentiation (P<0.05) in the nervous stem cells from different mouse models.(3) The expression of 4. 1R,4. 1G,4.1N and 4.1B in APP positive mice was significantly higher than that in APP negative and normal mice on the 15th day of differentiation (P<0.05). There was no significant difference in the expression of 4.1R,4.1G,4.1N and 4.1B among the other two APP negative and normal mice groups (P>0.05).(4) The expression levels of 4.1R,4.1G,4.1N and 4.1B mRNA in APP positive mice were significantly higher than those in APP negative and normal mice on the 15th day of differentiation (P<0. 05). There was no significant difference in the expression of 4.1R,4.1G,4.1N and 4.1B mRNA among the other two APP-negative and normal mice groups (P>0.05).ConclusionsThe four members of protein 4.1 family express in both mouse brain nervous stem cells and cells differentiated from them. The expression of protein 4.1 is higher in nervous cells from APP positive mice, suggesting their roles in pathogenesis of ADand interaction with amyloid precursor protein.