Identification of NLRP3 Inflammation-Related Gene Promoter Hypomethylation in Diabetic Retinopathy

Abstract

To identify and validate key genes that could provide a new perspective for genetic marker screening of diabetic retinopathy (DR). METHODS. The gene expression and DNA methylation profiles were obtained from the Gene Expression Omnibus. Differential expression analysis was conducted using the limma package, and then the functions of the differentially expressed genes (DEGs) were analyzed using the DAVID database, followed by protein-protein interaction (PPI) networks using Cytoscape software. We employed the Sequenom MassARRAY system to detect the promoter methylation levels of the candidate genes in peripheral blood mononuclear cells from 32 healthy individuals and 94 patients with type 2 diabetes mellitus (T2D; 64 with DR and 30 without DR) and in fibrovascular membranes (FVMs) from three proliferative DR patients and three controls with idiopathic epiretinal membranes. The mRNA levels of candidate genes were further confirmed via real-time polymerase chain reaction. RESULTS. A significant enrichment of 5906 DEGs was found in immune and inflammatory responses. TGFB1, CCL2, and TNFSF2 were identified as the top three core genes associated with NLRP3 inflammation in PPI networks. These genes have relatively low levels of promoter methylation, which have been validated in peripheral blood mononuclear cells and FVMs from DR patients, and the methylation levels were found to be negative correlated with the mRNA levels and HbA1c levels in T2D patients. CONCLUSIONS. Overall, these data indicate that promoter hypomethylation of NLRP3, TGFB1, CCL2, and TNFSF2 may increase the risk of DR in the Chinese Han population, indicating that these genes might serve as potential targets for the detection and treatment of DR.

HDAC3 Inhibition Alleviates High-Glucose-Induced Retinal Ganglion Cell Death through Inhibiting Inflammasome Activation

“…In a previous in vivo study, HDAC3 was found to promote obesity-related chronic inflammation by enhancing NLRP3 activation and subsequent inflammatory responses [ 17 ]. Both HDAC3 and NLRP3 were reported to be related to neurodegeneration in DR [ 18 ]; however, the detailed molecular mechanism remained unclear. In this current study, we focused on the expression pattern of HDAC3 in diabetes-related retinal neurodegeneration.…”

DNA methylation in diabetic retinopathy: pathogenetic role and potential therapeutic targets

“…Transcription of functional mediators, including pro-inflammatory cytokines, acute phase proteins and chemokines, is elevated, which act in the recruitment and activation of monocytes and leukocytes and in the subsequent inflammatory process [61]. DR is considered a chronic inflammatory disease related to the immune inflammatory response, which contributes to retinal angiogenesis and neurodegeneration [62] (Fig. 4).…”

“…NOD-like receptor (NLRP3) is important in the formation and activation of inflammatory bodies [68] and is associated with transforming growth factor beta-1 (TGFβ1) [69], monocyte chemoattractant protein-1 (MCP-1) [70], and tumor necrosis factor ligand superfamily member 2 (TNFSF2) [71], which together play a role in the development of vascular complications in DM. Studies have found that DR patients display reduced DNA methylation levels of NLRP3, suggesting the aberrant expression of inflammatory corpuscles in DR [62]. Moreover, compared with healthy individuals, levels of DNA methylation in the TGFβ1, MCP-1 and TNFSF2 genes are also significantly reduced in DR patients [62].…”

Genome-wide DNA methylation analysis of extreme phenotypes in the identification of novel epigenetic modifications in diabetic retinopathy

“…Maghbooli et al [7] noted changes in peripheral blood DNA methylation in DR patients, suggesting the potential value of DNA methylation as a biomarker for DR. However, DNA methylation studies conducted on type 2 diabetes mellitus (T2DM) cohorts based on traditional epigenome-wide association study (EWAS) approaches have yielded unclear results, failing to identify epigenetic modifications reproducibly associated with DR [8][9][10]. The results of these studies were skewed due to the incomplete phenotypes of the patients included.…”

“…Extreme phenotypic design is an emerging study design with superior power for detecting rare variants and has been suggested for the screening and identification of DR markers [11][12][13][14][15]. Further, previous studies followed a cross-sectional design and lack of optical coherence tomography (OCT) and OCTA (OCT angiography) biomarkers, which limits causal inferences and interpretations of their results [8][9][10]. Lastly, existing studies did not collect patients' systemic and ocular factors, specifically renal function and axial length (AL), which are known to be independently associated with DR onset and progression.…”