Résumé
Objective To investigate the effects of CTNND2 knockout on cerebellar neuronal development and motor function in mice, as well as its possible mechanisms. Methods The mice were divided into two groups (n = 10 in each group), all of them were 7 weeks old : wild-type (WT) C57BL/6J mice were treated as control group, and homozygous of CTNND2 knockout (CTNND2 7) mice were treated as experimental group, the genotype of CTNND2 7 mice were detected with PCR. The motor function of two groups were detected by beam walking test, hanging wire test and gait analysis test. The changes of cerebellar Purkinje cells were detected by immunofluorescence staining and Golgi staining. Western blotting was performed to detect the expression levels of synapse-associated proteins phosphorylated synapsin 1 (p-Synl), synapsin 1 (Synl), ELKS and postsynaptic density protein 95(PSD95), as well as phosphoinositide 3-kinase (PI3K), phosphorylated protein kinase B (p-Akt), protein kinase B (Akt), phosphorylated mammalian target of rapamycin (p-mTOR) and mammalian target of rapamycin (mTOR). Results Compared with the WT mice, except the increase in time to traverse the beam, there was a decrease in the proportion of pass on the beam, or latency to fall from the hanging wire, or score of hanging wire, or fore-stride length and hind-stride length of CTNND2 7 mice. There was also a decrease in numbers of Purkinje cells and its dendritic arborization in cerebellum of CTNND2 7 mice. The ratio of p-Synl/ Synl, p-Akt/Akt and p-mTOR/mTOR, as well as the expression levels of ELKS, PSD95 and PI3K were lower than those of WT mice. Conclusion CTNND2 knockout can affect the number and dendritic architecture of Purkinje cells, as well as synthesis of synapse-associated proteins in cerebellum by down-regulating PI3K/Akt/mT0R signaling pathway, resulting in cerebellar developmental disorder, thereby affecting motor function of mice.
Résumé
BackgroundHigh myopia is one of leading causes of blindness,so far the pathogenesis remains unclear.Two single-nucleotide polymorphisms (SNPs) of rs6885224 and rs12716080 in CTNND2 gene were recently found to be associated with high myopia in Singaporean Chinese.But whether these SNPs are related with the pathogenesis of high myopia in Han Chinese is worth studying,Objective This study was to investigate the relationship between the genetic variations of the CTNND2 gene and high myopia in Han Chinese.MethodsA case-controlled association study was designed.Nine hundred and thirty-three individuals with high myopia and 1227age- and gender-matched normal subjects were included in this study.The 5 ml of periphery blood was obtained from all subjects for the extraction of genomic DNA.The target DNA was amplified using PCR and purified by the SNaPshot method.Four SNPs rs12716080,rs917012,rs6885224 and rs16901340 in the CTNND2 gene were genotyped.This study was approved by the Ethic Committee of Sichuan Provincial People Hospital.Written informed consent was obtained from each subject before his/her enrollment.Results The frequencies of the genotypes rs6885224,rs12716080,rs917012,rs16901340 SNPs were in Hardy-Weinberg equilibrium (HWE) ( P=0.181,0.085,0.732,0.313,0.264,0.663,0.084,0.196).There were no significant differences in genotypes frequency distribution ( in turn P =0.654,0.406,0.828,0.403 ) and allele frequency distribution of the CTNND2 gene ( in turn P =0.377,0.209,0.743,0.198) between the high myopia group and normal control group.The haplotypes (TA and GA)frequencies of rs12716080 and rs917012 in the high myopia group were significantly different from those of the normal control group(TA:0.784 vs.0.719;GA:0.087 vs.0.136) (x2 =6.115,P=0.013 ;x2 =6.634,P=0.010),but those of GG were similar between the high myopia group and normal control group ( 0.123 vs.0.143,x2 =0.889,P =0.346). ConclusionsThe SNPs rs12716080,rs917012,rs6885224 and rs16901340 in CTNND2 gene were not responsible for high myopia,however,the haplotypes of rs12716080 and rs917012 are susceptible for high myopia in Han Chinese.