Inhibiting the NLRP3 inflammasome with MCC950 ameliorates retinal neovascularization and leakage by reversing the IL-1\u03b2/IL-18 activation pattern in an oxygen-induced ischemic retinopathy mouse model

Ailing Sui,Yixuan Yao,Yanji Zhu,Xi Shen,Bing Xie,Yiyun Yao,Anna M Demetriades,Jikui Shen,Xiuping Chen

doi:10.1038/s41419-020-03076-7

Abstract

Activation of the nucleotide-binding domain leucine-rich repeat and pyrin domain containing receptor 3 (NLRP3) inflammasome plays an important role in ocular neovascularization. In our study, we found that the expression and activation levels of NLRP3 inflammasome components, including NLRP3, an apoptosis-associated speck-like protein (ASC) containing caspase activation and recruitment domain (CARD) and caspase-1 (CAS1), were significantly upregulated. In addition, we found interleukin (IL)-1β activity increased while IL-18 activity decreased in the retinas of oxygen-induced ischemic retinopathy (OIR) mice. MCC950, an inhibitor of NLRP3, reversed the IL-1β/IL-18 activation pattern, inhibited the formation of retinal neovascularization (RNV), decreased the number of acellular capillaries and reduced leakage of retinal vessels. Moreover, MCC950 could regulate the expression of endothelial cell- and pericyte function-associated molecules, such as vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR)1, VEGFR2, matrix metalloproteinase (MMP)2, MMP9, tissue inhibitor of metalloproteinases (TIMP)1, TIMP2, platelet-derived growth factor receptor-β (PDGFR-β), platelet-derived growth factor-B (PDGF-B), and angiopoietin2 (Ang2). In vitro, recombinant human (r)IL-18 and rIL-1β regulated the expression of endothelial cell- and pericyte function-associated molecules and the proliferation and migration of endothelial cells and pericytes. We therefore determined that inhibiting the NLRP3 inflammasome with MCC950 can regulate the function of endothelial cells and pericytes by reversing the IL-1β/IL-18 activation pattern to ameliorate RNV and leakage; thereby opening new avenues to treat RNV-associated ocular diseases.

Highlights

Retinal neovascularization (RNV)-associated diseases such as retinal vein occlusion, diabetic retinopathy (DR), and retinopathy of prematurity (ROP), are characterized by pathological RNV and abnormal vascular permeability leading to retinal edema, hemorrhage, detachment, hyperplasia and other conditions, which seriously threaten vision and lead to visual decline[1,2,3]
Quantitative reverse transcription polymerase chain reaction results revealed that NLRP3, associated speck-like protein (ASC), and CAS1 mRNA expression was upregulated in the retinas of oxygen-induced ischemic retinopathy (OIR) mice from P13 to P21 (Fig. 1b–d)
The immunofluorescent staining of cells displayed increased positive staining of NLRP3 and CAS1 and the magnified z-stacks of confocal images clearly showed the formation of ASC specks and the colocalization of NLRP3 and ASC in the hypoxia-induced THP-1 cells (Supplementary Fig. S2), which were consistent with the experimental results in vivo

Summary

Introduction

Retinal neovascularization (RNV)-associated diseases such as retinal vein occlusion, diabetic retinopathy (DR), and retinopathy of prematurity (ROP), are characterized by pathological RNV and abnormal vascular permeability leading to retinal edema, hemorrhage, detachment, hyperplasia and other conditions, which seriously threaten vision and lead to visual decline[1,2,3]. As a member of the nucleotide-binding and oligomerization domain (NOD)-like receptor family that induces the adaptive immune response, the nucleotide-binding domain leucine-rich repeat and pyrin domain containing receptor 3 (NLRP3) inflammasome is an important part of the aseptic inflammatory reaction and the core component of the inflammatory protein complex composed of the innate immune receptor NLRP3, apoptosis-associated speck-like protein (ASC) containing caspase activation and recruitment domain and pro-caspase-1 (pro-CAS1)[11,12]. When cells are stimulated by endogenous or exogenous factors, the expression of interleukin-1β (IL-1β) and IL-18 changes, and the NLRP3 inflammasome is activated at the same time. In studies involving age-related macular degeneration (AMD), DR, and other retinopathies, researchers found that the NLRP3 inflammasome activation was the key factor leading to the proinflammatory effect, but the specific mechanism remains unknown[13,14]

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