Singapore Eye Research Institute, 20 College Road, The Academia Building, Singapore, 169856, Singapore.
Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore, 169857, Singapore.
Sci Rep. 2020 Mar 4;10(1):4011. doi: 10.1038/s41598-020-60944-0.
Protein aggregation has been one of the leading triggers of various disease conditions, such as Alzheimer's, Parkinson's and other amyloidosis. TGFBI-associated corneal dystrophies are protein aggregation disorders in which the mutant TGFBIp aggregates and accumulates in the cornea, leading to a reduction in visual acuity and blindness in severe cases. Currently, the only therapy available is invasive and there is a known recurrence after surgery. In this study, we tested the inhibitory and amyloid dissociation properties of four osmolytes in an in-vitro TGFBI peptide aggregation model. The 23-amino acid long peptide (TGFBIp 611-633 with the mutation c.623 G>R) from the 4th FAS-1 domain of TGFBIp that rapidly forms amyloid fibrils was used in the study. Several biophysical methods like Thioflavin T (ThT) fluorescence, Circular Dichroism (CD), fluorescence microscopy and Transmission electron microscopy (TEM) were used to study the inhibitory and amyloid disaggregation properties of the four osmolytes (Betaine, Raffinose, Sarcosine, and Taurine). The osmolytes were effective in both inhibiting and disaggregating the amyloid fibrils derived from TGFBIp 611-633 c.623 G>R peptide. The osmolytes did not have an adverse toxic effect on cultured human corneal fibroblast cells and could potentially be a useful therapeutic strategy for patients with TGFBIp corneal dystrophies.
蛋白质聚集已成为多种疾病的主要诱因之一，如阿尔茨海默病、帕金森病和其他淀粉样变性。TGFBI 相关角膜营养不良是一种蛋白质聚集紊乱，其中突变的 TGFBIp 聚集并在角膜中积累，导致视力下降，严重情况下可导致失明。目前，唯一可用的治疗方法是侵入性的，并且手术后已知会复发。在这项研究中，我们在 TGFBI 肽聚集模型的体外实验中测试了四种渗透剂的抑制和淀粉样纤维解聚特性。研究中使用了来自 TGFBIp 的第 4 个 FAS-1 结构域的 23 个氨基酸长肽（TGFBIp 611-633 与突变 c.623G>R），该肽迅速形成淀粉样原纤维。我们使用了几种生物物理方法，如硫黄素 T（ThT）荧光、圆二色性（CD）、荧光显微镜和透射电子显微镜（TEM）来研究这四种渗透剂（甜菜碱、棉子糖、肌氨酸和牛磺酸）的抑制和淀粉样纤维解聚特性。渗透剂在抑制和溶解源自 TGFBIp 611-633 c.623G>R 肽的淀粉样纤维方面均有效。这些渗透剂对培养的人角膜成纤维细胞没有不良的毒性作用，可能是治疗 TGFBIp 角膜营养不良患者的一种有用的治疗策略。
