摘要
目的研究GJB2基因条件敲除(cCx26Pax2Cre)小鼠耳蜗膜迷路细胞中凋亡相关基因的差异性表达情况,探讨GJB2基因突变导致耳聋的机制。方法由Cx26loxp/loxp和Pax2Cre/+小鼠杂交产生的cCx26Pax2Cre小鼠为实验组,野生型BALB/C小鼠作为正常对照组,两组分别选取P10和P18小鼠各3只,提取耳蜗膜迷路总RNA,反转录成cDNA,用QRT-PCR Array检测两组与凋亡相关的84个功能基因的表达差异。结果与野生型小鼠相比,cCx26Pax2Cre小鼠在P10时,共有16个基因表达有生物学意义(19.05%,16/84),其中14个基因表达下调(87.5%,14/16),包括9个抑制细胞凋亡和促进细胞增殖的基因下调和5个促进细胞凋亡和炎症反应的基因下调,2个基因表达上调(12.5%,2/16),均为促进细胞凋亡的基因,此期促进细胞凋亡的趋势十分明显;在P18时,共有4个基因(4.76%,4/84)表达变化有生物学意义,包括3个基因表达下调(75%),全部为抑制细胞凋亡的基因(100%),1个基因表达上调(25%),为促进细胞凋亡的基因,总体趋势仍为促进细胞凋亡的发生。与P10相比,cCx26Pax2Cre小鼠P18时耳蜗组织中共6个基因表达变化有生物学意义,其中促进细胞凋亡的caspase-8基因和抑制细胞凋亡的No13基因表达上调(33.3%,2/6),4个基因表达下调(66.7%,4/6),包括促进细胞凋亡的Tnfrsf10b、Cideb基因和抑制细胞凋亡的CD40、Bc110基因。结论 GJB2基因敲除后,可能通过上调死亡受体5(death receptor 5,DR5)激活死亡受体途径直接导致细胞凋亡,同时也可能通过caspase-8间接激活线粒体通路使凋亡信号进一步放大,最终引起cCx26Pax2Cre小鼠耳蜗细胞的广泛缺失和听力下降。
Objective To study the differential expression of apoptosis related genes in GJB2 gene conditional knockout mice （cCx26-pax2cre） cochlea membranous labyrinth, and to explore the mechanism of GJB2 gene mutations causing deafness. Methods Two developmental stages of Pl0 and P18 were selected from the knock out mice and the wild type ones （BALB/C）. The total RNA was isolated from cochlear membranous labyrinth and PCR array was performed using mouse apoptosis PCR arrays. Results Compared with wild--type mice, significant up or down-- regulation in gene expression was detected in 16 genes in eCx26--pax2cre ones at Pl0. Of the 16 genes, 14 ones were down--regulated. Among the 14 genes, 9 ones can be classified as anti--apoptosis or pro-proliferation genes,5 ones can be classified as pro--apoptosis or pro--inflammation genes. The other 2 genes expression was up--regula- ted, and their main role was to promote apoptosis. Compared with time--matched controls, significant up or down--regulation in gene expression was detected in 4 genes in cCx26-pax2cre mice at P18. Of the 4 genes, 3 ones expression was down--regulated, were anti--apoptosis ones. The expression of the other one gene among the 4 ones was up-- regulated, which acted as pro--apoptosis genes. Bc12110 and Tnfrsfl0b expression showed significant down or up-- regulation at both stages. Compared with P10, the expression of caspase --8 was up- ragulated at P18 in cCx26-pax2cre mice. Conclusion It is suggested that GJB2 mutation may up-- regulate the expression of DR5, which can trigger the death receptor pathway to cause apoptosis in cCx26-pax2cre mice cochlea directly. At the same time, caspase--8 in death receptor pathway may activate the mitochondria pathway indirectly and amplify the apoptosis further in cCx26-pax2cre mice cochlea. The final result of the above activated pathways is the wide range of cochlear cells apoptosis and the profound hearing loss in cCx26-pax2cre mice.
出处
《听力学及言语疾病杂志》
CAS
CSCD
北大核心
2014年第2期156-159,共4页
Journal of Audiology and Speech Pathology
基金
2013年度全军保健专项科研课题(13BJZ24)
全军十二五面上项目(11MS013)
国家自然科学基金面上项目青年基金(30700936)
中国人民解放军第309医院院内基金(LCB08MS12
309-09-03)
北京市自然科学基金(7142155)资助
