DNA Sensing via TLR-9 Constitutes a Major Innate Immunity Pathway Activated during Erythema Nodosum Leprosum.
J Immunol
; 197(5): 1905-13, 2016 09 01.
Article
em En
| MEDLINE
| ID: mdl-27474073
ABSTRACT
The chronic course of lepromatous leprosy may be interrupted by acute inflammatory episodes known as erythema nodosum leprosum (ENL). Despite its being a major cause of peripheral nerve damage in leprosy patients, the immunopathogenesis of ENL remains ill-defined. Recognized by distinct families of germline-encoded pattern recognition receptors, endogenous and pathogen-derived nucleic acids are highly immunostimulatory molecules that play a major role in the host defense against infections, autoimmunity, and autoinflammation. The aim of this work was to investigate whether DNA sensing via TLR-9 constitutes a major inflammatory pathway during ENL. Flow cytometry and immunohistochemistry analysis showed significantly higher TLR-9 expression in ENL when compared with nonreactional lepromatous patients, both locally in the skin lesions and in circulating mononuclear cells. The levels of endogenous and pathogen-derived TLR-9 ligands in the circulation of ENL patients were also higher. Furthermore, PBMCs isolated from the ENL patients secreted higher levels of TNF, IL-6, and IL-1ß in response to a TLR-9 agonist than those of the nonreactional patients and healthy individuals. Finally, E6446, a TLR-9 synthetic antagonist, was able to significantly inhibit the secretion of proinflammatory cytokines by ENL PBMCs in response to Mycobacterium leprae lysate. Our data strongly indicate that DNA sensing via TLR-9 constitutes a major innate immunity pathway involved in the pathogenesis and evolution of ENL. Thus, the use of TLR-9 antagonists emerges as a potential alternative to more effectively treat ENL aiming to prevent the development of nerve injuries and deformities in leprosy.
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Base de dados:
MEDLINE
Assunto principal:
DNA
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Hanseníase Virchowiana
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Transdução de Sinais
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Eritema Nodoso
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Receptor Toll-Like 9
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Imunidade Inata
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article