Bone marrow chimeras and c-fms conditional ablation (Mafia) mice reveal an essential role for resident myeloid cells in lipopolysaccharide/TLR4-induced corneal inflammation.
The mammalian cornea contains an extensive network of resident macrophages and dendritic cells. To determine the role of these cells in LPS-induced corneal inflammation, TLR4(-/-) mice were sublethally irradiated and reconstituted with bone marrow cells from either enhanced GFP (eGFP)(+)/C57BL/6 or eGFP(+)/TLR4(-/-) mice. The corneal epithelium was abraded, LPS was added topically, and cellular infiltration to the corneal stroma and development of corneal haze were examined after 24 h. TLR4(-/-) mice reconstituted with C57BL/6, but not TLR4(-/-) bone marrow cells donor cells were found to cause infiltration of eGFP(+) cells to the cornea, including neutrophils, and also increased corneal haze compared with saline-treated corneas. In a second experimental approach, corneas of transgenic macrophage Fas induced apoptosis (Mafia) mice were stimulated with LPS. These mice express eGFP and a suicide gene under control of the c-fms promoter, and systemic treatment with the FK506 dimerizer (AP20187) causes Fas-mediated apoptosis of monocytic cells. AP20187-treated mice had significantly fewer eGFP(+) cells in the cornea than untreated mice. After stimulation with LPS neutrophil recruitment and development of corneal haze were impaired in AP20187-treated mice compared with untreated controls. Furthermore, LPS induced CXCL1/KC and IL-1alpha production within 4 h in corneas of untreated Mafia mice, which is before cellular infiltration; however, cytokine production was impaired after AP20187 treatment. Together, results from both experimental approaches demonstrate an essential role for resident corneal monocytic lineage cells (macrophages and dendritic cells) in development of corneal inflammation.
Chinnery
Holly R
HR
School of Anatomy and Human Biology and the Lions Eye Institute, The University of Western Australia, Crawley, Western Australia, Australia.
Carlson
Eric C
EC
Sun
Yan
Y
Lin
Michelle
M
Burnett
Sandra H
SH
Perez
Victor L
VL
McMenamin
Paul G
PG
Pearlman
Eric
E
D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000276:immunology; D016026:Bone Marrow Transplantation / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D018836:Inflammation Mediators / Q000008:administration & dosage / Q000378:metabolism / Q000633:toxicity; D007634:Keratitis / Q000235:genetics / Q000276:immunology* / Q000473:pathology*; D008070:Lipopolysaccharides / Q000633:toxicity*; D008264:Macrophages / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D022423:Myeloid Cells / Q000276:immunology* / Q000378:metabolism; D011828:Radiation Chimera / Q000276:immunology; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000096:biosynthesis / Q000172:deficiency* / Q000235:genetics*; D051197:Toll-Like Receptor 4 / Q000008:administration & dosage / Q000172:deficiency / Q000235:genetics*; D019014:fas Receptor / Q000502:physiology
D018836:Inflammation Mediators; D008070:Lipopolysaccharides; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; C485184:enhanced green fluorescent protein; D019014:fas Receptor; D049452:Green Fluorescent Proteins; D016186:Receptor, Macrophage Colony-Stimulating Factor