FLNA promotes the progression of diabetic retinopathy by increasing M1 macrophages

To clarify the role of filamin A (FLNA) in promoting diabetic retinopathy (DR) progression and explore its underlying mechanism via modulating M1 macrophage inflammation and adenosine 5'-monophosphate activated protein kinase (AMPK) phosphorylation, as well as its potential as a diagnostic biomarker and therapeutic target.

Gene Expression Omnibus (GEO) dataset and Weighted Gene Co-Expression Network Analysis (WGCNA) were used to identify differentially expressed genes across DR, diabetes mellitus (DM), and control groups. Gene Set Enrichment Analysis (GSEA), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) were employed to analyze the enrichment of intersecting genes. Machine learning models assessed the predictive performance of these genes, while single-cell sequencing and cell chat examined their expression in M1 macrophages and interactions with other cell types. Quantitative PCR (q-PCR) measured mRNA levels of interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α), and Western blotting assessed protein levels of FLNA, AMPK, and phosphorylated-AMPK (p-AMPK).

Key findings revealed FLNA, plectin (PLEC), and Tweety family member 3 (TTYH3) as critical genes in DR, with FLNA showing the highest area under the curve (AUC) value and importance, and the random forest model performing best. The AMPK signaling pathway was enriched for FLNA, which was most significantly expressed in M1 macrophages. M1 macrophages promote IL-6, IL-1β, and TNF-α expression. FLNA increases the effect of M1 macrophages on DR progression and AMPK phosphorylation.

Our study identifies FLNA as a key regulator in DR progression, primarily by enhancing M1 macrophage-mediated inflammation and AMPK phosphorylation. These findings highlight FLNA's critical role in DR pathogenesis and its potential as a biomarker for early diagnosis and a therapeutic target for intervening in macrophage-driven inflammatory responses.