PDF(Pubmed)
Abstract：
ABCA4-related retinopathy is the most common inherited Mendelian eye disorder worldwide, caused by biallelic variants in the ATP-binding cassette transporter ABCA4. To date, over 2200 ABCA4 variants have been identified, including missense, nonsense, indels, splice site and deep intronic defects. Notably, more than 60% are missense variants that can lead to protein misfolding, mistrafficking and degradation. Currently no approved therapies target ABCA4. In this study, we demonstrate that ABCA4 misfolding variants are temperature-sensitive and reduced temperature growth (30 °C) improves their traffic to the plasma membrane, suggesting the folding of these variants could be rescuable. Consequently, an in vitro platform was developed for the rapid and robust detection of ABCA4 traffic to the plasma membrane in transiently transfected cells. The system was used to assess selected candidate small molecules that were reported to improve the folding or traffic of other ABC transporters. Two candidates, 4-PBA and AICAR, were identified and validated for their ability to enhance both wild-type ABCA4 and variant trafficking to the cell surface in cell culture. We envision that this platform could serve as a primary screen for more sophisticated in vitro testing, enabling the discovery of breakthrough agents to rescue ABCA4 protein defects and mitigate ABCA4-related retinopathy.
摘要：
ABCA4相关视网膜病变是全球最常见的遗传性孟德尔眼病，由ATP结合盒转运蛋白ABCA4中的双等位基因变体引起。迄今为止,超过2200种ABCA4变种已被鉴定,包括错觉,胡说，indels,剪接部位和深内含子缺陷。值得注意的是,超过60%是可能导致蛋白质错误折叠的错义变体，误入歧途和退化。目前没有批准的疗法靶向ABCA4。在这项研究中,我们证明ABCA4错误折叠变体是温度敏感的，降低的温度生长（30°C）改善了它们对质膜的运输，表明这些变体的折叠是可以挽救的。因此,我们开发了一个体外平台,用于在瞬时转染的细胞中快速和稳健地检测ABCA4向质膜的转运.该系统用于评估所选候选小分子,据报道所述候选小分子可改善其他ABC转运蛋白的折叠或运输。两位候选人,4-PBA和AICAR，鉴定并验证了它们在细胞培养物中增强野生型ABCA4和变体向细胞表面运输的能力。我们设想这个平台可以作为更复杂的体外测试的主要屏幕，能够发现突破性药物来挽救ABCA4蛋白缺陷并减轻ABCA4相关视网膜病变。
