Susceptibility to Coccidioides species in C57BL/6 mice is associated with expression of a truncated splice variant of Dectin-1 (Clec7a).
Coccidioides posadasii spherules stimulate macrophages to make cytokines via TLR-2 and Dectin-1. We used formalin-killed spherules and 1,3-beta-glucan purified from spherules to stimulate elicited peritoneal macrophages and myeloid dendritic cells (mDCs) from susceptible (C57BL/6) and resistant (DBA/2) mouse strains. DBA/2 macrophages produced more TNF-alpha and IL-6 than macrophages from C57BL/6 mice, and the amount of TNF-alpha made was dependent on both TLR2 and Dectin-1. DCs from C57BL/6 mice made more IL-10 and less IL-23p19 and IL-12p70 than did DBA/2 DC. These responses were inhibited by a monoclonal antibody to Dectin-1. DBA/2 mice expressed full-length Dectin-1, whereas C57BL/6 mice spliced out exon 3, which encodes most of the stalk. RAW cells transduced to express the full-length Dectin-1 responded better to FKS than cells expressing truncated Dectin-1. We compared the isoform of Dectin-1 expressed by 34 C57BL/6 X DBA/2 recombinant inbred (BXD RI) lines with their susceptibility to Coccidioides immitis. In 25 of 34 RI lines susceptibility or resistance corresponded to short or full-length isoforms, respectively. These results suggest that alternative splicing of the Dectin-1 gene contributes to susceptibility of C57BL/6 mice to coccidioidomycosis, and affects the cytokine responses of macrophages and mDCs to spherules.
del Pilar Jiménez-A
M
M
Research Service, VA San Diego Healthcare, San Diego, CA 92161, USA.
Viriyakosol
S
S
Walls
L
L
Datta
S K
SK
Kirkland
T
T
Heinsbroek
S E M
SE
Brown
G
G
Fierer
J
J
D017398:Alternative Splicing; D000818:Animals; D002460:Cell Line; D003045:Coccidioides / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology; D003047:Coccidioidomycosis / Q000276:immunology* / Q000382:microbiology / Q000503:physiopathology; D003713:Dendritic Cells / Q000378:metabolism; D015870:Gene Expression; D020022:Genetic Predisposition to Disease; D007113:Immunity, Innate; D016753:Interleukin-10 / Q000096:biosynthesis; D037181:Lectins, C-Type; D017737:Macrophages, Peritoneal / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D013045:Species Specificity; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D000099181:Dectin-1
D016753:Interleukin-10; D037181:Lectins, C-Type; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D014409:Tumor Necrosis Factor-alpha; D000099181:Dectin-1