Department of Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama.
Invest Ophthalmol Vis Sci. 2013 Oct 11;54(10):6675-85. doi: 10.1167/iovs.13-12550.
To determine whether the age-regulating protein klotho was expressed in the retina and determine whether the absence of klotho affected retinal function.
Immunohistochemistry and qPCR of klotho knockout and wild-type mice were used to detect klotho expression in retina. Immunohistochemistry was used to probe for differences in expression of proteins important in synaptic function, retinal structure, and ionic flux. Electroretinography (ERG) was conducted on animals across lifespan to determine whether decreased klotho expression affects retinal function.
Klotho mRNA and protein were detected in the wild-type mouse retina, with protein present in all nuclear layers. Over the short lifespan of the knockout mouse (∼8 weeks), no overt photoreceptor cell loss was observed, however, function was progressively impaired. At 3 weeks of age neither protein expression levels (synaptophysin and glutamic acid decarboxylase [GAD67]) nor retinal function were distinguishable from wild-type controls. However, by 7 weeks of age expression of synaptophysin, glial fibrillary acidic protein (GFAP), and transient receptor potential cation channel subfamily member 1 (TRPM1) decreased while GAD67, post synaptic density 95 (PSD95), and wheat germ agglutinin staining, representative of glycoprotein sialic acid residues, were increased relative to wild-type mice. Accompanying these changes, profound functional deficits were observed as both ERG a-wave and b-wave amplitudes compared with wild-type controls.
Klotho is expressed in the retina and is important for healthy retinal function. Although the mechanisms for the observed abnormalities are not known, they are consistent with the accelerating aging phenotype seen in other tissues.
确定衰老调节蛋白 klotho 是否在视网膜中表达，并确定 klotho 的缺失是否会影响视网膜功能。
使用 klotho 敲除和野生型小鼠的免疫组织化学和 qPCR 检测 klotho 在视网膜中的表达。免疫组织化学用于探测在突触功能、视网膜结构和离子通量中重要的蛋白质的表达差异。对动物进行视网膜电图 (ERG) 检测，以确定 klotho 表达减少是否会影响视网膜功能。
klotho mRNA 和蛋白在野生型小鼠视网膜中被检测到，蛋白存在于所有核层中。在敲除鼠的短寿命（约 8 周）内，未观察到明显的光感受器细胞丢失，但是功能逐渐受损。在 3 周龄时，突触小体蛋白（synaptophysin）和谷氨酸脱羧酶 67（GAD67）的蛋白表达水平或视网膜功能与野生型对照均无区别。然而，到 7 周龄时，synaptophysin、胶质纤维酸性蛋白（glial fibrillary acidic protein，GFAP）和瞬时受体电位阳离子通道亚家族成员 1（transient receptor potential cation channel subfamily member 1，TRPM1）的表达下降，而 GAD67、后突触密度 95（post synaptic density 95，PSD95）和小麦胚凝集素染色（代表糖蛋白唾液酸残基）增加，与野生型小鼠相比。伴随着这些变化，与野生型对照相比，观察到明显的功能缺陷，表现为 ERG a 波和 b 波幅度降低。
klotho 在视网膜中表达，对健康的视网膜功能很重要。虽然观察到的异常的机制尚不清楚，但它们与其他组织中观察到的加速衰老表型一致。
