Endothelin-2-Mediated Protection of Mutant Photoreceptors in Inherited Photoreceptor Degeneration
Endothelin-2-Mediated Protection of Mutant Photoreceptors in Inherited Photoreceptor Degeneration
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DOI：
10.1371/journal.pone.0058023
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发表时间：
2013-02-28
期刊：
影响因子：
3.7
通讯作者：
McInnes, Roderick R.
中科院分区：
文献类型：
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作者：
Bramall, Alexa N.;Szego, Michael J.;McInnes, Roderick R.
在遗传性 PR 变性 (IPD) 小鼠模型的光感受器 (PR) 中，内皮素 2 (Edn2) mRNA 的表达大大增加。为了检查Edn2在突变PR存活中的作用，我们产生了携带纯合Pde6b(rd1)等位基因或Tg(RHO P347S)转基因的Edn2(-/-)小鼠。在Edn2(-/-)背景下，Pde6b(rd1/rd1)小鼠在出生后(PN)第15天PR存活率增加了110%，而Tg(RHO P347S)小鼠在PN40时PR存活率增加了60%。相比之下，Pde6b(rd1/rd1) 的视网膜外植体中 PR 存活率并未增加； Edn2(-/-) 小鼠。这一发现与Edn2(-/-)小鼠的系统性异常一起表明，Edn2(-/-)背景中突变PR的存活率增加至少部分是由于系统性EDN2功能丧失所致。为了直接检查 EDN2 在突变 PR 中的作用，我们使用 scAAV5-Edn2 cDNA 载体恢复 Pde6b(rd1/rd1) 中的 Edn2 表达； Edn2(-/-) PR 并观察到 PN14 时 PR 存活率增加了 18%。重要的是，将 scAAV5-Edn2 注射到 Pde6b(rd1/rd1) 视网膜后，PR 存活率在 PN15 时增加了 31%。总之，这些发现表明增加的 Edn2 表达对突变 PR 具有保护作用。为了开始阐明有助于 PR 存活的 Edn2 介导机制，我们使用微阵列分析并鉴定了一组 20 个基因，其中 Tg(RHO P347S) 视网膜中的表达增加了 4 倍以上，其中包括 Fgf2。值得注意的是，Tg(RHO P347S) PR 中 FGF2 蛋白表达的增加在 Tg(RHO P347S) 中被消除； Edn2(-/-) 视网膜。我们的研究结果表明，PR Edn2 表达增加可增加 PR 存活率，并表明 FGF2 PR 表达的 Edn2 依赖性增加可能有助于延长存活率。
Expression of the Endothelin-2 (Edn2) mRNA is greatly increased in the photoreceptors (PRs) of mouse models of inherited PR degeneration (IPD). To examine the role of Edn2 in mutant PR survival, we generated Edn2(-/-) mice carrying homozygous Pde6b(rd1) alleles or the Tg(RHO P347S) transgene. In the Edn2(-/-) background, PR survival increased 110% in Pde6b(rd1/rd1) mice at post-natal (PN) day 15, and 60% in Tg(RHO P347S) mice at PN40. In contrast, PR survival was not increased in retinal explants of Pde6b(rd1/rd1); Edn2(-/-) mice. This finding, together with systemic abnormalities in Edn2(-/-) mice, suggested that the increased survival of mutant PRs in the Edn2(-/-) background resulted at least partly from the systemic EDN2 loss of function. To examine directly the role of EDN2 in mutant PRs, we used a scAAV5-Edn2 cDNA vector to restore Edn2 expression in Pde6b(rd1/rd1); Edn2(-/-) PRs and observed an 18% increase in PR survival at PN14. Importantly, PR survival was also increased after injection of scAAV5-Edn2 into Pde6b(rd1/rd1) retinas, by 31% at PN15. Together, these findings suggest that increased Edn2 expression is protective to mutant PRs. To begin to elucidate Edn2-mediated mechanisms that contribute to PR survival, we used microarray analysis and identified a cohort of 20 genes with >4-fold increased expression in Tg(RHO P347S) retinas, including Fgf2. Notably, increased expression of the FGF2 protein in Tg(RHO P347S) PRs was ablated in Tg(RHO P347S); Edn2(-/-) retinas. Our findings indicate that the increased expression of PR Edn2 increases PR survival, and suggest that the Edn2-dependent increase in PR expression of FGF2 may contribute to the augmented survival.