| Objective and background:Age-related macular degeneration（AMD）is the third leading cause of blindness in China.In recent years,anti-vascular endothelial growth factor（VEGF）drugs have made a breakthrough in the treatment of wet AMD.However,about 25%of the patients did not respond to the treatment,37%of the respondents still developed low vision or blindness,and some patients developed retinal fibrosis and map atrophy.In addition,there is still no breakthrough in the treatment of dry AMD which makes up 85%of AMD,so the development of drugs for the treatment of dry AMD is still at the forefront of ophthalmology research.FGF-21 is a relatively new member of the FGF family,which can perform a variety of biological functions on multiple target organs,including antioxidation,anti-inflammation and so on.Previous studies have proved that through long-term injection of FGF-21 recombinant protein into mice and the study of Fgf-21transgenic mice,it is found that FGF-21 has significant life-prolonging and anti-aging effects on rodents,and AMD is related to aging,oxidative stress,chronic inflammation and other diseases.Therefore,we speculate that FGF-21 may have a therapeutic effect on dry AMD,but it is still lack of experimental evidence.Therefore,this study intends to explain the feasibility of FGF-21 in the treatment of dry AMD.Methods:1)Fgf-21 gene knockout mice were fed,and transmission electron microscope and OCT technique were used to detect whether dry AMD-like lesions occurred in the fundus of elderly mice under the condition of FGF-21 gene deletion.2)Proteomic technique was used to detect the changes of RPE/choroidal protein expression in the eyes of mice with Fgf-21 gene deletion,in order to clarify the effect of FGF-21 gene deletion on protein expression profile in AMD lesions.3)Dry AMD model was made with hydroquinone.Transmission electron microscope and OCT technique were used to detect whether the intervention of FGF-21 recombinant protein could alleviate the occurrence and development of dry AMD.At the same time,we tried to use the fusion expression of 9-polyarginine and FGF-21 to detect whether the Arg9-FGF-21 fusion protein could be entered into the eye by eye drops,so as to play a role in the treatment of dry AMD.Fluorescence quantitative PCR and Western were used to detect the effect of FGF-21on the expression of inflammatory factors and regulation pathway NF-κB in RPE/choroidal tissue.4)FGFR1,which is necessary for FGF-21 to acts its role,were used to fish small molecules which can bound to FGFR1 by SPR fishing technique,and their affinity with FGFR1 was characterized.5)ARPE-19 cells were used to detect the effects of FGF-21 and small molecules on oxidative damage and inflammatory factor secretion.Results:1)Transmission electron microscope showed dry BrM-like changes in the fundus of 3-month-old and 10-month-old Fgf-21knockout mice,which were characterized by thickening of AMD,deposits in the membrane and loose cell structure,especially in10-month-old mice.2)Proteomic results showed that complement pathway was significantly active and MAC content was significantly increased in RPE/choroidal protein expression profile of Fgf-21 knockout mice,and FGF-21 intervention could inhibit complement production.3)Dry AMD-like lesions in Fgf-21 knockout mice were more significant under the intervention of hydroquinone,while intraperitoneal injection of FGF-21 could delay the occurrence and development of dry AMD by reducing the level of intraocular inflammation.4)Six small molecules were fished by FGFR1,one of which had specific affinity with FGFR1.Cell culture showed that the small molecule could promote the phosphorylation of FGFR1 and showed antioxidant and anti-inflammatory activities.Conclusions:The above results of this study suggest that Fgf-21 deletion can enhance intraocular inflammation and promote the occurrence and development of dry AMD.Intraperitoneal injection of FGF-21 can inhibit NF-κB signal pathway,inhibit inflammatory response,and improve complement activation-induced RPE cell injury and retinal morphological changes.Screening small molecules binding to FGFR1 can provide a new idea for the development of new dry AMD therapeutic drugs.This study provides strong evidence for the development of clinical application of FGF-21 as a drug for the prevention and treatment of dry AMD and provides a new target for the prevention and treatment of dry AMD. |
