Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, 325003, China.
Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
Sci Rep. 2017 Aug 30;7(1):9992. doi: 10.1038/s41598-017-10117-3.
To identify possible genetic variants influencing expression of EPHA2 (Ephrin-receptor Type-A2), a tyrosine kinase receptor that has been shown to be important for lens development and to contribute to both congenital and age related cataract when mutated, the extended promoter region of EPHA2 was screened for variants. SNP rs6603883 lies in a PAX2 binding site in the EPHA2 promoter region. The C (minor) allele decreased EPHA2 transcriptional activity relative to the T allele by reducing the binding affinity of PAX2. Knockdown of PAX2 in human lens epithelial (HLE) cells decreased endogenous expression of EPHA2. Whole RNA sequencing showed that extracellular matrix (ECM), MAPK-AKT signaling pathways and cytoskeleton related genes were dysregulated in EPHA2 knockdown HLE cells. Taken together, these results indicate a functional non-coding SNP in EPHA2 promoter affects PAX2 binding and reduces EPHA2 expression. They further suggest that decreasing EPHA2 levels alters MAPK, AKT signaling pathways and ECM and cytoskeletal genes in lens cells that could contribute to cataract. These results demonstrate a direct role for PAX2 in EPHA2 expression and help delineate the role of EPHA2 in development and homeostasis required for lens transparency.
为了鉴定可能影响 EPHA2（Ephrin-receptor Type-A2）表达的遗传变异，Ephrin-receptor Type-A2 是一种酪氨酸激酶受体，已被证明在晶状体发育中很重要，当发生突变时会导致先天性和年龄相关性白内障。对 EPHA2 的扩展启动子区域进行了变异筛选。SNP rs6603883 位于 EPHA2 启动子区域的 PAX2 结合位点内。与 T 等位基因相比，C（次要）等位基因降低了 PAX2 的结合亲和力，从而降低了 EPHA2 的转录活性。在人晶状体上皮（HLE）细胞中敲低 PAX2 会降低内源性 EPHA2 的表达。全 RNA 测序显示，EPHA2 敲低的 HLE 细胞中细胞外基质（ECM）、MAPK-AKT 信号通路和细胞骨架相关基因失调。总之，这些结果表明 EPHA2 启动子中的功能性非编码 SNP 会影响 PAX2 的结合并降低 EPHA2 的表达。它们进一步表明，降低 EPHA2 水平会改变晶状体细胞中的 MAPK、AKT 信号通路和 ECM 以及细胞骨架基因，这可能导致白内障。这些结果表明 PAX2 直接参与 EPHA2 的表达，并有助于描绘 EPHA2 在晶状体透明性所需的发育和动态平衡中的作用。
