SARS-CoV-2 treatment effects induced by ACE2-expressing microparticles are explained by the oxidized cholesterolincreased endosomal pH of alveolar macrophages

摘要

Exploring the cross-talk between the immune system and advanced biomaterials to treat SARS-CoV-2 infection is a promising strategy.Here,we show that ACE2-overexpressing A549 cell-derived microparticles(AO-MPs)are a potential therapeutic agent against SARS-CoV-2 infection.Intranasally administered AO-MPs dexterously navigate the anatomical and biological features of the lungs to enter the alveoli and are taken up by alveolar macrophages(AMs).Then,AO-MPs increase the endosomal pH but decrease the lysosomal pH in AMs,thus escorting bound SARS-CoV-2 from phago-endosomes to lysosomes for degradation.This pH regulation is attributable to oxidized cholesterol,which is enriched in AO-MPs and translocated to endosomal membranes,thus interfering with proton pumps and impairing endosomal acidification.In addition to promoting viral degradation,AO-MPs also inhibit the proinflammatory phenotype of AMs,leading to increased treatment efficacy in a SARS-CoV-2-infected mouse model without side effects.These findings highlight the potential use of AO-MPs to treat SARS-CoV-2-infected patients and showcase the feasibility of MP therapies for combatting emerging respiratory viruses in the future.