Chlamydial heat shock protein 60 induces acute pulmonary inflammation in mice via the Toll-like receptor 4- and MyD88-dependent pathway.
Heat shock protein 60 derived from Chlamydia pneumoniae (cHSP60) activates Toll-like receptor 4 (TLR4) signaling through the MyD88 pathway in vitro, but it is not known how cHSP60 contributes to C. pneumoniae-induced lung inflammation. We treated wild-type (WT), TLR2(-/-), TLR4(-/-), or MyD88(-/-) mice intratracheally (i.t.) with recombinant cHSP60 (50 microg), UV-killed C. pneumoniae (UVCP; 5 x 10(6) inclusion-forming units/mouse), lipopolysaccharide (2 microg), or phosphate-buffered saline (PBS) and sacrificed mice 24 h later. Bronchoalveolar lavage (BAL) was obtained to measure cell counts and cytokine levels, lungs were analyzed for histopathology, and lung homogenate chemokine concentrations were determined. Bone marrow-derived dendritic cells (BMDDCs) were generated and stimulated with live C. pneumoniae (multiplicity of infection [MOI], 5), UVCP (MOI, 5), or cHSP60 for 24 h, and the expression of costimulatory molecules (CD80 and CD86) was measured by fluorescence-activated cell sorting. cHSP60 induced acute lung inflammation with the same intensity as that of UVCP-induced inflammation in WT mice but not in TLR4(-/-) or MyD88(-/-) mice. cHSP60- and UVCP-induced lung inflammation was associated with increased numbers of cells in BAL, increased neutrophil recruitment, and elevated BAL interleukin-6 (IL-6) levels. Both cHSP60 and UVCP induced IL-6 release and CD80 and CD86 expression in WT cells but not in MyD88(-/-) BMDDCs. cHSP60 stimulated DC activation in a TLR4- and MyD88-dependent manner with an intensity similar to that induced by UVCP. These data suggest that cHSP60 promotes lung inflammation and DC activation via TLR4 and MyD88 and therefore may play a significant role in the pathogenesis of C. pneumoniae-induced chronic inflammatory lung diseases.
Bulut
Yonca
Y
Cedars-Sinai Medical Center, Division of Pediatrics Infectious Diseases and Immunology, Los Angeles, CA 90048, USA.
Shimada
Kenichi
K
Wong
Michelle H
MH
Chen
Shuang
S
Gray
Pearl
P
Alsabeh
Randa
R
Doherty
Terence M
TM
Crother
Timothy R
TR
Arditi
Moshe
M
D000818:Animals; D018122:B7-1 Antigen / Q000096:biosynthesis; D051940:B7-2 Antigen / Q000096:biosynthesis; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology / Q000276:immunology; D018834:Chaperonin 60 / Q000502:physiology*; D016993:Chlamydophila pneumoniae / Q000472:pathogenicity*; D016207:Cytokines / Q000032:analysis; D003713:Dendritic Cells / Q000276:immunology; D008168:Lung / Q000737:chemistry / Q000276:immunology / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D053594:Myeloid Differentiation Factor 88 / Q000172:deficiency / Q000276:immunology*; D018410:Pneumonia, Bacterial / Q000276:immunology* / Q000382:microbiology / Q000473:pathology*; D051197:Toll-Like Receptor 4 / Q000172:deficiency / Q000276:immunology*
D018122:B7-1 Antigen; D051940:B7-2 Antigen; C497965:Cd86 protein, mouse; D018834:Chaperonin 60; D016207:Cytokines; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4