Abnormal expression and dysfunction of methyl-CpG binding protein 2 （MeCP2） cause Rett syndrome （RTT）. The diverse phosphorylation modifications modulate MeCP2 function in neural cells. Using western blot and immunohistochemistry, we examined the expression patterns of MeCP2 and three phospho-MeCP2s （pMeCP2s） in the developing rat brain. The expression of MeCP2 and phospho-S80 （pS80） MeCP2 increased while pS421 MeCP2 and pS292 MeCP2 decreased with brain maturation. In contrast to the nuclear localization of MeCP2 and pS80 MeCP2, pS421 MeCP2 and pS292 MeCP2 were mainly expressed in the cytoplasmic com- partment. Apart from their distribution in neurons, they were also detected at a low level in astrocytes. Postnatallyinitiated MeCP2 deficiency affected cerebellar neural cell development, as determined by the abnormal expression of GFAP, DCX, Tuj 1, MAP-2, and calbindin-D28k. Together, these results demonstrate that MeCP2 and diverse pMeCP2s have distinct features of spatio-temporal expression in the rat brain, and that the precise levels of MeCP2 in the postnatal period are vital to cerebellar neural cell development.
Micro RNA-365(mi R-365) is upregulated in the ischemic brain and is involved in oxidative damage in the diabetic rat. However, it is unclear whether mi R-365 regulates oxidative stress(OS)-mediated neuronal damage after ischemia. Here, we used a transient middle cerebral artery occlusion model in rats and the hydrogen peroxide-induced OS model in primary cultured neurons to assess the roles of mi R-365 in neuronal damage. We found that mi R-365 exacerbated ischemic brain injury and OS-induced neuronal damage and was associated with a reduced expression of OXR1(Oxidation Resistance 1). In contrast, mi R-365 antagomir alleviated both the brain injury and OXR1 reduction. Luciferase assays indicated that mi R-365 inhibited OXR1 expression by directly targeting the 30-untranslated region of Oxr1. Furthermore, knockdown of OXR1 abolished the neuroprotective and antioxidant effects of the mi R-365 antagomir. Our results suggest that mi R-365 upregulationincreases oxidative injury by inhibiting OXR1 expression,while its downregulation protects neurons from oxidative death by enhancing OXR1-mediated antioxidant signals.
Jia-Lin MoZhi-Guang PanXiao ChenYu LeiLing-Ling LvCheng QianFeng-Yan Sun
Objective It has been reported that B-cell lymphoma 2 （Bcl-2） enhances neurogenesis as well as supporting axonal growth after injury. In the present study, we investigated whether Bcl-2 overexpression plays a role in the formation of newborn striatonigral projection neurons in the adult rat brain after transient middle cerebral artery occlusion （MCAO）. Methods We infused human Bcl-2-expressing plasmid （pBcl-2） into the lateral ventricle immediately after 30 min of MCAO, injected 5＇-bromodeoxyuridine （BrdU） intraperitoneally to label proliferative cells, and microinjected fluorogold （FG） into the substantia nigra at 11 weeks of reperfusion followed by multiple immunostaining of striatonigral projection neurons at 12 weeks. Results We found that pBcl-2 treatment significantly increased the number of newborn neurons （BrdU＋-NeuN＋） in the striatum ipsilateral to the MCAO. We further detected newborn striatonigral projection neurons （BrdU＋-FG＋-NeuN＋） in the ipsilateral striatum at 12 weeks. More interestingly, the number of newborn striatonigral projection neurons （BrdU＋-FG＋） was significantly increased by pBcl-2 treatment compared to that by pEGFP, a control plasmid. Conclusion Taken together, we found that Bcl-2 overexpression in the brain enhanced the generation of newborn striatonigral projection neurons. This provides a potential strategy for promoting the reestablishment of neural networks and brain repair after ischemic injury.
Jian-Jun GuoFang LiuXiao SunJun-Jie HuangMing XuFeng-Yan Sun
