Multiple TLRs are expressed in human cholangiocytes and mediate host epithelial defense responses to Cryptosporidium parvum via activation of NF-κB

Xian-Ming Chen, Steven P. O'Hara, Jeremy B. Nelson, Patrick L. Splinter, Aaron J. Small, Pamela S. Tietz, Andrew H. Limper, Nicholas F. LaRusso

Research output: Contribution to journalArticle

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Abstract

Infection of epithelial cells by Cryptosporidium parvum triggers a variety of host-cell innate and adaptive immune responses including release of cytokines/chemokines and up-regulation of antimicrobial peptides. The mechanisms that trigger these host-cell responses are unclear. Thus, we evaluated the role of TLRs in host-cell responses during C. parvum infection of cultured human biliary epithelia (i.e., cholangiocytes). We found that normal human cholangiocytes express all known TLRs. C. parvum infection of cultured cholangiocytes induces the selective recruitment of TLR2 and TLR4 to the infection sites. Activation of several downstream effectors of TLRs including IL-1R-associated kinase, p-38, and NF-κB was detected in infected cells. Transfection of cholangiocytes with dominant-negative mutants of TLR2 and TLR4, as well as the adaptor molecule myeloid differentiation protein 88 (MyD88), inhibited C. parvum-induced activation of IL-1R-associated kinase, p-38, and NF-κB. Short-interfering RNA to TLR2, TLR4, and MyD88 also blocked C. parvum-induced NF-κB activation. Moreover, C. parvum selectively up-regulated human β-defensin-2 in directly infected cells, and inhibition of TLR2 and TLR4 signals or NF-κB activation were each associated with a reduction of C. parvum-induced human β-defensin-2 expression. A significantly higher number of parasites were detected in cells transfected with a MyD88 dominant-negative mutant than in the control cells at 48-96 h after initial exposure to parasites, suggesting MyD88-deficient cells were more susceptible to infection. These findings demonstrate that cholangiocytes express a variety of TLRs, and suggest that TLR2 and TLR4 mediate cholangiocyte defense responses to C. parvum via activation of NF-κB.

Original languageEnglish
Pages (from-to)7447-7456
Number of pages10
JournalJournal of Immunology
Volume175
Issue number11
StatePublished - Dec 1 2005
Externally publishedYes

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Cryptosporidium parvum
Defensins
Infection
Parasites
Proteins
Phosphotransferases
Adaptive Immunity
Chemokines
Innate Immunity
Small Interfering RNA
Transfection
Up-Regulation
Epithelium
Epithelial Cells
Cytokines
Peptides

All Science Journal Classification (ASJC) codes

  • Immunology

Cite this

Chen, X-M., O'Hara, S. P., Nelson, J. B., Splinter, P. L., Small, A. J., Tietz, P. S., ... LaRusso, N. F. (2005). Multiple TLRs are expressed in human cholangiocytes and mediate host epithelial defense responses to Cryptosporidium parvum via activation of NF-κB. Journal of Immunology, 175(11), 7447-7456.

Multiple TLRs are expressed in human cholangiocytes and mediate host epithelial defense responses to Cryptosporidium parvum via activation of NF-κB. / Chen, Xian-Ming; O'Hara, Steven P.; Nelson, Jeremy B.; Splinter, Patrick L.; Small, Aaron J.; Tietz, Pamela S.; Limper, Andrew H.; LaRusso, Nicholas F.

In: Journal of Immunology, Vol. 175, No. 11, 01.12.2005, p. 7447-7456.

Research output: Contribution to journalArticle

Chen, X-M, O'Hara, SP, Nelson, JB, Splinter, PL, Small, AJ, Tietz, PS, Limper, AH & LaRusso, NF 2005, 'Multiple TLRs are expressed in human cholangiocytes and mediate host epithelial defense responses to Cryptosporidium parvum via activation of NF-κB', Journal of Immunology, vol. 175, no. 11, pp. 7447-7456.
Chen, Xian-Ming ; O'Hara, Steven P. ; Nelson, Jeremy B. ; Splinter, Patrick L. ; Small, Aaron J. ; Tietz, Pamela S. ; Limper, Andrew H. ; LaRusso, Nicholas F. / Multiple TLRs are expressed in human cholangiocytes and mediate host epithelial defense responses to Cryptosporidium parvum via activation of NF-κB. In: Journal of Immunology. 2005 ; Vol. 175, No. 11. pp. 7447-7456.
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abstract = "Infection of epithelial cells by Cryptosporidium parvum triggers a variety of host-cell innate and adaptive immune responses including release of cytokines/chemokines and up-regulation of antimicrobial peptides. The mechanisms that trigger these host-cell responses are unclear. Thus, we evaluated the role of TLRs in host-cell responses during C. parvum infection of cultured human biliary epithelia (i.e., cholangiocytes). We found that normal human cholangiocytes express all known TLRs. C. parvum infection of cultured cholangiocytes induces the selective recruitment of TLR2 and TLR4 to the infection sites. Activation of several downstream effectors of TLRs including IL-1R-associated kinase, p-38, and NF-κB was detected in infected cells. Transfection of cholangiocytes with dominant-negative mutants of TLR2 and TLR4, as well as the adaptor molecule myeloid differentiation protein 88 (MyD88), inhibited C. parvum-induced activation of IL-1R-associated kinase, p-38, and NF-κB. Short-interfering RNA to TLR2, TLR4, and MyD88 also blocked C. parvum-induced NF-κB activation. Moreover, C. parvum selectively up-regulated human β-defensin-2 in directly infected cells, and inhibition of TLR2 and TLR4 signals or NF-κB activation were each associated with a reduction of C. parvum-induced human β-defensin-2 expression. A significantly higher number of parasites were detected in cells transfected with a MyD88 dominant-negative mutant than in the control cells at 48-96 h after initial exposure to parasites, suggesting MyD88-deficient cells were more susceptible to infection. These findings demonstrate that cholangiocytes express a variety of TLRs, and suggest that TLR2 and TLR4 mediate cholangiocyte defense responses to C. parvum via activation of NF-κB.",
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AU - Splinter, Patrick L.

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AU - Tietz, Pamela S.

AU - Limper, Andrew H.

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