Deletion of thioredoxin-interacting protein (Txnip) abrogates high fat diet-induced retinal leukostasis, barrier dysfunction and microvascular degeneration in a mouse obesity model

Abstract

We have shown that a high fat diet (HFD) induces the activation of retinal NOD-like receptor protein (NLRP3)-inflammasome that is associated with enhanced expression and interaction with thioredoxin-interacting protein (TXNIP). Here, the specific contribution of TXNIP and the impact of HFD on retinal leukostasis, barrier dysfunction and microvascular degeneration were investigated. Wild-type (WT) and TXNIP knockout (TKO) mice were fed with normal diet or 60% HFD for 8–18 weeks. TXNIP was overexpressed or silenced in human retinal endothelial cells (REC). At 8 weeks, HFD significantly induced retinal leukostasis and breakdown of the blood–retina barrier in WT mice, but not in TKO mice. In parallel, HFD also induced retinal expression of adhesion molecules and cleaved IL-1β in WT mice, which were also abrogated in TKO mice. In culture, TXNIP overexpression induced NLRP3, IL-1β, and adhesion molecules expression, while TXNIP silencing inhibited them. Blocking the IL-1β receptor significantly suppressed TXNIP-induced expression of NLRP3-inflammasome and adhesion molecules in HREC. Ex-vivo assay showed that leukocytes isolated from WT-HFD, but not from TKO-HFD, induced leukostasis and cell death. At 18 weeks, HFD triggered development of degenerated (acellular) capillaries and decreased branching density in WT but not in TKO mice. Together, HFD-induced obesity triggered early retinal leukostasis and microvascular dysfunction at least in part via TXNIP-NLRP3-inflammasome activation.