The Regulation Of 20S Proteasome To The Proliferative Potential Of Neural Stem Cells In SVZ

Objective:To reveal the effect of the activity of proteasome on proliferation potential in neural stem cell, observe the expression of 20S proteasome of neural stem cells in SVZ and the activity change of 20S proteasome in the aging process, to provide a new breakthrough to delay the aging process of the bodyMethods:Mice were divided into five groups which are embryonic 14 days (E14),postnatal day (P0),Postnatal 30 days (P30),Postnatal 60 days (P60),Postnatal 540 days (P540) 1.to observe the expression of nestin and 20S proteasome of neural stem cells in SVZ through immunofluorescence.2.to extract proteins in SVZ from the E14,P0,P30,P60,P540 mouse, then semi-quantitative analysis the expression change of 20s proteasome at different ages with Western Blot method.3.to extract the proteins in SVZ from the E14,P0,P30,P60,P540mouse, to detect the activity of 20S proteasome of different ages in mice by fluorimetric method.4. To inject proteasome inhibitor MG132 into lateral ventricle of the adult mouse, then take the intraperitoneal injection of Brdu after 3days,7 days, to detect proteasome inhibitors on the proliferative potential of NSCs by immunofluorescence staining BrdU+.Results:1.20S proteasome positive cells can be seen in both cytoplasm and the nucleus, round, distributed along the lateral ventricle wall, and the neural stem cell marker nestin also expressed in the same cells which suggest 20S proteasome may have a regulatory role in NSCs.2. The western-blot results show that the expression of 20S proteasome gradually decreased with age. The expression of 20S proteasome from embryonic mouse is highest, compared to aged mouse, it has a statistically significant difference (p< 0.05).3.Proteasome activity of the test results also show the activity of 20S proteasome is on the decrease with age, in which the activity of 20S proteasome from E14,P0,P30 mice were significantly higher than which from the P540 mice (p<0.05), but the activity of 20S proteasome from P60 mice and P540 mice has no significant difference(p>0.05).4. MG132 intervention results showed that after injection of MG132 3days and 7 days, The number of BrdU+ cells are decreased in SVZ. After injection of MG132 3days, The number of BrdU+ cells are decreased (2±0.1), compared with the DMSO group (22±3), it has a statistically significant difference (p<0.05). After injection of MG132 7days, The number of BrdU+ cells are decreased (3±1), compared with the DMSO group (8±3), it has a statistically significant difference (p<0.05). Which indicate the decreased activity of 20Sproteasome led to the decrease of proliferative potential in NSCs.Conclusion:(1)the expression and activity of 20S proteasome gradually reducedand in SVZ NSCs with age; which suggest the decreased activity of 20S proteasome may result in the senescence of NSCs and the aging of the body.(2) Proteasome inhibitors can significantly inhibit the proliferation potential of NSCs, indicating that aging of the body may make proteasome dysfunction which induce to the depletion of NSCs library and aging-related diseasesby.