title: Increased CD40 Expression Enhances Early STING-Mediated Type I Interferon Response and Host Survival in a Rodent Malaria Model.
abstract: Both type I interferon (IFN-I) and CD40 play a significant role in various infectious diseases, including malaria and autoimmune disorders. CD40 is mostly known to function in adaptive immunity, but previous observations of elevated CD40 levels early after malaria infection of mice led us to investigate its roles in innate IFN-I responses and disease control. Using a Plasmodium yoelii nigeriensis N67 and C57BL/6 mouse model, we showed that infected CD40-/- mice had reduced STING and serum IFN-β levels day-2 post infection, higher day-4 parasitemia, and earlier deaths. CD40 could greatly enhance STING-stimulated luciferase signals driven by the IFN-β promoter in vitro, which was mediated by increased STING protein levels. The ability of CD40 to influence STING expression was confirmed in CD40-/- mice after malaria infection. Substitutions at CD40 TRAF binding domains significantly decreased the IFN-β signals and STING protein level, which was likely mediated by changes in STING ubiquitination and degradation. Increased levels of CD40, STING, and ISRE driven luciferase signal in RAW Lucia were observed after phagocytosis of N67-infected red blood cells (iRBCs), stimulation with parasite DNA/RNA, or with selected TLR ligands [LPS, poly(I:C), and Pam3CSK4]. The results suggest stimulation of CD40 expression by parasite materials through TLR signaling pathways, which was further confirmed in bone marrow derived dendritic cells/macrophages (BMDCs/BMDMs) and splenic DCs from CD40-/-, TLR3-/- TLR4-/-, TRIF-/-, and MyD88-/- mice after iRBC stimulation or parasite infection. Our data connect several signaling pathways consisting of phagocytosis of iRBCs, recognition of parasite DNA/RNA (possibly GPI) by TLRs, elevated levels of CD40 and STING proteins, increased IFN-I production, and longer host survival time. This study reveals previously unrecognized CD40 function in innate IFN-I responses and protective pathways in infections with malaria strains that induce a strong IFN-I response, which may provide important information for better understanding and management of malaria.
authors.affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Xiangyu
authors.initials: X
authors.lastname: Yao
authors.affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Jian
authors.initials: J
authors.lastname: Wu
authors.affiliation: Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, Texas, United States of America.
authors.forename: Meng
authors.initials: M
authors.lastname: Lin
authors.affiliation: Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Wenxiang
authors.initials: W
authors.lastname: Sun
authors.affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Xiao
authors.initials: X
authors.lastname: He
authors.affiliation: Department of Biochemistry and Molecular Biology, College of Medicine, Pennsylvania State University, Hershey, Pennsylvania, United States of America.
authors.forename: Channe
authors.initials: C
authors.lastname: Gowda
authors.affiliation: Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Silvia
authors.initials: S
authors.lastname: Bolland
authors.affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Carole A
authors.initials: CA
authors.lastname: Long
authors.affiliation: Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, Texas, United States of America.
authors.forename: Rongfu
authors.initials: R
authors.lastname: Wang
authors.affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Xin-Zhuan
authors.initials: XZ
authors.lastname: Su
mesh_terms: D000818:Animals; D015153:Blotting, Western; D019013:CD40 Antigens / Q000096:biosynthesis / Q000276:immunology*; D004195:Disease Models, Animal; D005455:Fluorescent Antibody Technique; D057809:HEK293 Cells; D006790:Host-Parasite Interactions / Q000276:immunology*; D006801:Humans; D047468:Immunoprecipitation; D007370:Interferon Type I / Q000276:immunology*; D008288:Malaria / Q000276:immunology*; D008565:Membrane Proteins / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010967:Plasmodium yoelii / Q000276:immunology; D000099197:STING Protein
chemical_list: D019013:CD40 Antigens; D007370:Interferon Type I; D008565:Membrane Proteins; C530855:Sting1 protein, mouse; D000099197:STING Protein