P0977LOW EXPRESSION OF AUTOPHAGY-RELATED PROTEIN 5 (ATG5) LEADS TO SUPPRESSION OF AUTOPHAGY IN PATIENTS WITH DIABETIC NEPROPATHY AND RETINOPATHY. (6th June 2020)

• Record Type: Journal Article
• Authors: Nakhoul, Nakhoul; Nakhoul, Rula; Abass, Remah; Farber, Evgeny; Tadmor, Hagar; Nakhoul, Farid
• Is Part Of: Nephrology dialysis transplantation. Volume 35(2020)Supplement 3
• Publication Date: 2020-06-06
• Subjects: Nephrology -- Periodicals; Hemodialysis -- Periodicals; Kidneys -- Transplantation -- Periodicals; Hemodialysis; Kidneys -- Transplantation; Nephrology; Periodicals; 616.61
• DOI: 10.1093/ndt/gfaa142.P0977
• Languages: English
• ISSNs: 0931-0509

Abstract

Abstract: Background and Aims: Autophagy is a catabolic mechanism that involves lysosomal-dependent degradation of unnecessary or dysfunctional intracellular components. Autophagy plays role in many biological processes, including diabetic nephropathy (DN) and diabetic retinopathy (DR). Autophagy-related gene 5 (ATG5) is one of the most important participants in the autophagy mechanism. Deficiencies in ATG5 protein levels are associated with several diseases by influencing the level of autophagy pathway. Our study's aim was to investigate if aberrant expression of ATG5 protein or Atg5 gene is associated with DN or DR. Method: The study included 120 human participants in 4 groups – Healthy, diabetic (DM), DN and DR; and 10 mice in 2 groups – healthy and DN. Western blot analyses of ATG5 and its downstream collaborator LC3B were performed on human white blood cell (WBC) lysates and murine renal lysates. Immunohistochemical analysis was performed on mice renal tissues. Quantitative real-time PCR analysis of ATG5 was performed on total mRNA isolated from human WBC. Results: ATG5 protein expression by western blot analysis was significantly decreased in DM patients, with and without complications [0.66 ± 0.06 A.U in DM patients (n=30 p <0.01), 0.62 ± 0.06 A.U in DN, (n=30 p<0.001) and 0.67± 0.05 A.U in DR patients (n=30 p<0.01)], compared with the healthy control subjects [0.97 ± 0.04 A.U (n=30)]. There was nearly a 2.5-fold decrease in the percentage of ATG5-stained areas in the tubules of DN mice (4.42 ± 1.08%) compared with W.T mice (10.87 ± 1.01%). The expression of Atg5 gene between the various study groups by qRT-PCR analyses ( fig.1 ), the Atg5 gene in DN (0.0069 ± 0.0005) and DR patients (0.0069 ± 0.0004) was down regulated at the mRNA levels, compared with healthy controls (0.0083 ± 0.0008). substantial reduction of LC3-II levels (autophagy marker) in DM patients (0.50 ± 0.04 A.U, n=18 p < 0.001) DN patients (0.44 ± 0.05 A.U, n=19 p < 0.001) and DR patients (0.43 ± 0.05 A.U, n=18 p < 0.001) compared with the healthy control individuals (0.81 ± 0.05 A.U n=19). The renal LC3-II protein expression was found to be greatly decreased in the tubules of DN mice when compared with W.T mice Conclusion: Our findings indicate that ATG5, as well as its downstream collaborator LC3-II, are often down-regulated in diabetic patients, which contributes to deficiencies in autophagy process. Impairment of this process can lead to accumulation of abnormal proteins and damage molecules that can lead to the development and progression of DN &DR. Therapeutic potential of ATG5 modulations as a novel treatment strategy for DN or DR patients through the autophagy mechanism, as well as ATG5 may serve as a goal in the development of drugs for diabetic and its complications.