Vitamin A and its biologically active derivative,retinoic acid(RA),are important for many immune processes.RA,in particular,is essential for the development of immune cells,including neutrophils,which serve as a front...Vitamin A and its biologically active derivative,retinoic acid(RA),are important for many immune processes.RA,in particular,is essential for the development of immune cells,including neutrophils,which serve as a front-line defense against infection.Although vitamin A deficiency has been linked to higher susceptibility to infections,the precise role of vitamin A/RA in host-pathogen interactions remains poorly understood.Here,we provided evidence that RA boosts neutrophil killing of methicillin-resistant Staphylococcus aureus(MRSA).RA treatment stimulated primary human neutrophils to produce reactive oxygen species,neutrophil extracellular traps and the antimicrobial peptide cathelicidin(LL-37).Because RA treatment was insufficient to reduce MRSA burden in an in vivo murine model of skin infection,we expanded our analysis to other infectious agents.RA did not affect the growth of a number of common bacterial pathogens,including MRSA,Escherichia coli K1 and Pseudomonas aeruginosa;however,RA directly inhibited the growth of group A Streptococcus(GAS).This antimicrobial effect,likely in combination with RA-mediated neutrophil boosting,resulted in substantial GAS killing in neutrophil killing assays conducted in the presence of RA.Furthermore,in a murine model of GAS skin infection,topical RA treatment showed therapeutic potential by reducing both skin lesion size and bacterial burden.These findings suggest that RA may hold promise as a therapeutic agent against GAS and perhaps other clinically significant human pathogens.展开更多
Neutrophil extracellular traps(NETs)can capture and kill viruses,such as influenza viruses,human immunodeficiency virus(HIV),and respiratory syncytial virus(RSV),thus contributing to host defense.Contrary to our expec...Neutrophil extracellular traps(NETs)can capture and kill viruses,such as influenza viruses,human immunodeficiency virus(HIV),and respiratory syncytial virus(RSV),thus contributing to host defense.Contrary to our expectation,we show here that the histones released by NETosis enhance the infectivity of SARS-CoV-2,as found by using live SARS-CoV-2 and two pseudovirus systems as well as a mouse model.The histone H3 or H4 selectively binds to subunit 2 of the spike(S)protein,as shown by a biochemical binding assay,surface plasmon resonance and binding energy calculation as well as the construction of a mutant S protein by replacing four acidic amino acids.Sialic acid on the host cell surface is the key molecule to which histones bridge subunit 2 of the S protein.Moreover,histones enhance cell-cell fusion.Finally,treatment with an inhibitor of NETosis,histone H3 or H4,or sialic acid notably affected the levels of sgRNA copies and the number of apoptotic cells in a mouse model.These findings suggest that SARS-CoV-2 could hijack histones from neutrophil NETosis to promote its host cell attachment and entry process and may be important in exploring pathogenesis and possible strategies to develop new effective therapies for COVID-19.展开更多
基金US National Institutes of Health grants(R01-AI145325 to VN and R37-AI052453 to VN and RLG)a BioLegend Graduate Fellowship in Immunology.
文摘Vitamin A and its biologically active derivative,retinoic acid(RA),are important for many immune processes.RA,in particular,is essential for the development of immune cells,including neutrophils,which serve as a front-line defense against infection.Although vitamin A deficiency has been linked to higher susceptibility to infections,the precise role of vitamin A/RA in host-pathogen interactions remains poorly understood.Here,we provided evidence that RA boosts neutrophil killing of methicillin-resistant Staphylococcus aureus(MRSA).RA treatment stimulated primary human neutrophils to produce reactive oxygen species,neutrophil extracellular traps and the antimicrobial peptide cathelicidin(LL-37).Because RA treatment was insufficient to reduce MRSA burden in an in vivo murine model of skin infection,we expanded our analysis to other infectious agents.RA did not affect the growth of a number of common bacterial pathogens,including MRSA,Escherichia coli K1 and Pseudomonas aeruginosa;however,RA directly inhibited the growth of group A Streptococcus(GAS).This antimicrobial effect,likely in combination with RA-mediated neutrophil boosting,resulted in substantial GAS killing in neutrophil killing assays conducted in the presence of RA.Furthermore,in a murine model of GAS skin infection,topical RA treatment showed therapeutic potential by reducing both skin lesion size and bacterial burden.These findings suggest that RA may hold promise as a therapeutic agent against GAS and perhaps other clinically significant human pathogens.
基金supported by the National Science Foundation for Excellent Young Scholars (32122052)National Natural Science Foundation Regional Innovation and Development (No.U19A2003).
文摘Neutrophil extracellular traps(NETs)can capture and kill viruses,such as influenza viruses,human immunodeficiency virus(HIV),and respiratory syncytial virus(RSV),thus contributing to host defense.Contrary to our expectation,we show here that the histones released by NETosis enhance the infectivity of SARS-CoV-2,as found by using live SARS-CoV-2 and two pseudovirus systems as well as a mouse model.The histone H3 or H4 selectively binds to subunit 2 of the spike(S)protein,as shown by a biochemical binding assay,surface plasmon resonance and binding energy calculation as well as the construction of a mutant S protein by replacing four acidic amino acids.Sialic acid on the host cell surface is the key molecule to which histones bridge subunit 2 of the S protein.Moreover,histones enhance cell-cell fusion.Finally,treatment with an inhibitor of NETosis,histone H3 or H4,or sialic acid notably affected the levels of sgRNA copies and the number of apoptotic cells in a mouse model.These findings suggest that SARS-CoV-2 could hijack histones from neutrophil NETosis to promote its host cell attachment and entry process and may be important in exploring pathogenesis and possible strategies to develop new effective therapies for COVID-19.
