The RPE-derived NF-κB/HO-1/MCP-1 pathway mediated Microglia Recruitment Involved in the Outer Blood-Retinal Barrier Breakdown in Experimental Diabetic Retinopathy

  • Exp Cell Res. 2025 Oct 30:114813. doi: 10.1016/j.yexcr.2025.114813.
Yiyang Shu  1 ,  Dandan Liu  2 ,  Hai Xie  3 ,  Chaoyang Zhang  4 ,  Yanlong Bi  5 ,  Jingfa Zhang  6
Affiliations
  • 1. Department of Ophthalmology, The Affiliated People's Hospital of Ningbo University, The Eye Hospital of Wenzhou Medical University (Ningbo Branch), Ningbo 315040, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China; Department of Ophthalmology, Tongji Hospital, School of Medicine, Tongji University, Tongji Eye Institute, School of Medicine, Tongji University, Shanghai 200065, PR China.
  • 2. Department of Clinical Laboratory, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China.
  • 3. Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, 200030, China.
  • 4. The Primasia International Eye Research Institute of the Chinese University of Hong Kong (Shenzhen), C-MER (Shenzhen) Dennis Lam Eye Hospital, Shenzhen, 518000, China. Electronic address: [email protected].
  • 5. Department of Ophthalmology, Tongji Hospital, School of Medicine, Tongji University, Tongji Eye Institute, School of Medicine, Tongji University, Shanghai 200065, PR China. Electronic address: [email protected].
  • 6. The Primasia International Eye Research Institute of the Chinese University of Hong Kong (Shenzhen), C-MER (Shenzhen) Dennis Lam Eye Hospital, Shenzhen, 518000, China; C-MER Dennis Lam & Partners Eye Center, C-MER International Eye Care Group, 999077, Hong Kong, China. Electronic address: [email protected].
PMID: 41176205 DOI: 10.1016/j.yexcr.2025.114813
Abstract

Purpose: To investigate the mechanisms underlying the microglia recruitment and its causal role in the breakdown of the outer blood-retinal barrier (oBRB) in diabetic retinopathy (DR).

Methods: The Sprague-Dawley rats were adopted to establish diabetic model by intraperitoneal injection of streptozotocin. Twelve weeks later, the retinal pigment epithelium (RPE)-choroid complexes and retinal paraffin sections were examined with immunofluorescence. RNA-sequencing was performed on glyoxal-treated ARPE-19 cells, followed by bioinformatic analysis to identify significant genes and pathways. Transwell assays were employed to establish the co-culture system and investigate the interactions between ARPE-19 and BV2 microglial cells. The results were further validated by the inhibitor or siRNAs targeting NF-κB, HO-1, and MCP-1.

Results: In 12-week diabetic rat retinas, microglia cells were observed to accumulate in the vicinity of the RPE cells, accompanied by the disruption of ZO-1. The expressions of ZO-1 and occludin remained largely unchanged in ARPE-19 cells when treated with glyoxal alone. However, when co-cultured with BV2 microglial cells, the expression levels of ZO-1 and occludin in glyoxal-treated ARPE-19 cells were significantly decreased, which were effectively prevented by siMCP-1. Mechanistically, RNA-sequencing analysis revealed that the activation of the NF-κB/HO-1/MCP-1 pathway in glyoxal-treated ARPE-19 cells significantly contributed to the recruitment of microglia. The above effects were reversed by BAY 11-7082, siHO-1 or siMCP-1.

Conclusion: Under diabetic condition, microglia are recruited by RPE cells via the NF-κB/HO-1/MCP-1 pathway, which subsequently result in the oBRB breakdown. This study provides a novel mechanistic insight for the interaction between microglia and RPE cells, and implies a potential therapeutic strategy for the treatment of DR.

Keywords
Diabetic retinopathy; Microglia; NF-κB/HO-1/MCP-1 pathway; Outer blood-retinal barrier; RPE.
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