Role of NLRP3 Inflammasomes in Monocyte and Microglial Recruitments in Choroidal Neovascularization

Immunohorizons. 2024 May 1;8(5):363-370. doi: 10.4049/immunohorizons.2400025.

Abstract

Although the pathogenesis of choroidal neovascularization (CNV) is largely unknown in age-related macular degeneration (AMD), inflammasomes may contribute to CNV development and progression. To understand the role NLRP3 inflammasomes in CNV, we used Ccr2RFPCx3cr1GFP dual-reporter mice and immunostaining techniques to confirm localization of NLRP3 inflammasomes in the laser-induced CNV (LCNV) lesions. Confocal microscopy was used to image and quantify LCNV volumes. MCC950 was used as NLRP3 inhibitor. ELISA and quantitative RT-PCR were used to confirm the activation of NLRP3 by monitoring the expression of IL-1β protein and mRNA in choroidal tissues from LCNV mice. In addition, NLRP3 (-/-) LCNV mice were used to investigate whether NLRP3 inflammasomes contribute to the development of LCNV lesions. We observed that red fluorescent protein (RFP)-positive monocyte-derived macrophages and GFP-positive microglia-derived macrophages, in addition to other cell types, were localized in LCNV lesions at day 7 post-laser injury. In addition, NLRP3 inflammasomes are associated with LCNV lesions. Inhibition of NLRP3 inflammasomes, using MCC950, caused an increased Ccr2RFP-positive macrophages, Cx3cr1GFP-positive microglia, and other cells, resulting in an increase in total lesion size. NLRP3 (-/-) LCNV mice showed significantly increased lesion size compared with age-matched controls. Inhibition of NLRP3 resulted in decreased IL-1β mRNA and protein expression in the choroidal tissues, suggesting that increased lesion size may not be directly related to IL-1β.

MeSH terms

  • Animals
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Choroid / metabolism
  • Choroid / pathology
  • Choroidal Neovascularization* / metabolism
  • Choroidal Neovascularization* / pathology
  • Disease Models, Animal
  • Furans / pharmacology
  • Heterocyclic Compounds, 4 or More Rings / pharmacology
  • Indenes*
  • Inflammasomes* / metabolism
  • Interleukin-1beta* / metabolism
  • Lasers / adverse effects
  • Macrophages / immunology
  • Macrophages / metabolism
  • Macular Degeneration / genetics
  • Macular Degeneration / metabolism
  • Macular Degeneration / pathology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Microglia* / metabolism
  • Monocytes* / metabolism
  • NLR Family, Pyrin Domain-Containing 3 Protein* / genetics
  • NLR Family, Pyrin Domain-Containing 3 Protein* / metabolism
  • Receptors, CCR2 / genetics
  • Receptors, CCR2 / metabolism
  • Sulfonamides / pharmacology
  • Sulfones / pharmacology

Substances

  • Nlrp3 protein, mouse
  • N-(1,2,3,5,6,7-hexahydro-S-indacen-4-ylcarbamoyl)-4-(2-hydroxy-2-propanyl)-2-furansulfonamide
  • Ccr2 protein, mouse