Molecular phenotype of SLC4A11 missense mutants: Setting the stage for personalized medicine in corneal dystrophies
Molecular phenotype of SLC4A11 missense mutants: Setting the stage for personalized medicine in corneal dystrophies
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DOI：
10.1002/humu.23401
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发表时间：
2018-05-01
期刊：
影响因子：
3.9
通讯作者：
Casey, Joseph R.
中科院分区：
文献类型：
--
作者：
Alka, Kumari;Casey, Joseph R.
SLC4A11 突变会导致先天性遗传性内皮营养不良 (CHED)、Harboyan 综合征 (HS) 和福克斯内皮性角膜营养不良 (FECD)。角膜内皮细胞（CEC）从角膜基质重吸收水分的缺陷会导致角膜营养不良。 SLC4A11 位于 CEC 基底外侧膜中，促进 H2O、NH3 和 H+ 等价物的跨膜运动。一些 SLC4A11 疾病突变体折叠受损，导致无法移动到细胞表面，在某些情况下可以通过药物 Glafenine 来纠正。为了鉴定作为折叠校正治疗靶标的 SLC4A11 突变体，我们检查了 54 个 SLC4A11 错义突变体。通过免疫印迹，通过成熟、高分子量、细胞表面相关形式的水平，并使用生物发光共振能量转移测定来评估细胞表面运输。在 18 个 FECD 突变体中的 4 个 (20%)、31 个 CHED 突变体中的 19 个 (61%) 以及五分之三 (60%) 的 HS 突变体中发现了低水平的细胞表面运输。在 ER 保留的突变体中，有 16 个在 30 摄氏度下生长时显示出质膜运输增加，这表明它们的缺陷有可能得到挽救。引起 CHED 的点突变主要导致折叠缺陷，而大多数 FECD 错义突变不影响运输，这意味着功能障碍。我们发现了使患者成为角膜营养不良折叠矫正候选者的突变。
SLC4A11 mutations cause cases of congenital hereditary endothelial dystrophy (CHED), Harboyan syndrome (HS), and Fuchs endothelial corneal dystrophy (FECD). Defective water reabsorption from corneal stroma by corneal endothelial cells (CECs) leads to these corneal dystrophies. SLC4A11, in the CEC basolateral membrane, facilitates transmembrane movement of H2O, NH3, and H+-equivalents. Some SLC4A11 disease mutants have impaired folding, leading to a failure to move to the cell surface, which in some cases can be corrected by the drug, glafenine. To identify SLC4A11 mutants that are targets for folding-correction therapy, we examined 54 SLC4A11 missense mutants. Cell-surface trafficking was assessed on immunoblots, by the level of mature, high molecular weight, cell surface-associated form, and using a bioluminescence resonance energy transfer assay. Low level of cell surface trafficking was found in four out of 18 (20%) of FECD mutants, 19/ out of 31 (61%) of CHED mutants, and three out of five (60%) of HS mutants. Amongst ER-retained mutants, 16 showed increased plasma membrane trafficking when grown at 30 degrees C, suggesting that their defect has potential for rescue. CHED-causing point mutations mostly resulted in folding defects, whereas the majority of FECD missense mutations did not affect trafficking, implying functional impairment. We identified mutations that make patients candidates for folding correction of their corneal dystrophy.