title: miR-27b targets KSRP to coordinate TLR4-mediated epithelial defense against Cryptosporidium parvum infection.
abstract: Cryptosporidium is a protozoan parasite that infects the gastrointestinal epithelium and causes a diarrheal disease. Toll-like receptor (TLR)- and NF-κB-mediated immune responses from epithelial cells, such as production of antimicrobial peptides and generation of reactive nitrogen species, are important components of the host's defense against cryptosporidial infection. Here we report data demonstrating a role for miR-27b in the regulation of TLR4/NF-κB-mediated epithelial anti-Cryptosporidium parvum responses. We found that C. parvum infection induced nitric oxide (NO) production in host epithelial cells in a TLR4/NF-κB-dependent manner, with the involvement of the stabilization of inducible NO synthase (iNOS) mRNA. C. parvum infection of epithelial cells activated NF-κB signaling to increase transcription of the miR-27b gene. Meanwhile, downregulation of KH-type splicing regulatory protein (KSRP) was detected in epithelial cells following C. parvum infection. Importantly, miR-27b targeted the 3'-untranslated region of KSRP, resulting in translational suppression. C. parvum infection decreased KSRP expression through upregulating miR-27b. Functional manipulation of KSRP or miR-27b caused reciprocal alterations in iNOS mRNA stability in infected cells. Forced expression of KSRP and inhibition of miR-27b resulted in an increased burden of C. parvum infection. Downregulation of KSRP through upregulating miR-27b was also detected in epithelial cells following LPS stimulation. These data suggest that miR-27b targets KSRP and modulates iNOS mRNA stability following C. parvum infection, a process that may be relevant to the regulation of epithelial anti-microbial defense in general.
authors.affiliation: Department of Medical Microbiology and Immunology, Creighton University Medical Center, Omaha, Nebraska, United States of America.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhou
authors.forename: Ai-Yu
authors.initials: AY
authors.lastname: Gong
authors.forename: Alex N
authors.initials: AN
authors.lastname: Eischeid
authors.forename: Xian-Ming
authors.initials: XM
authors.lastname: Chen
mesh_terms: D000818:Animals; D002460:Cell Line; D003457:Cryptosporidiosis / Q000276:immunology*; D016785:Cryptosporidium parvum / Q000235:genetics / Q000276:immunology*; D004847:Epithelial Cells / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000469:parasitology; D005786:Gene Expression Regulation; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D035683:MicroRNAs / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism; D012326:RNA Splicing; D012333:RNA, Messenger; D016601:RNA-Binding Proteins / Q000378:metabolism*; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000276:immunology* / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: C507913:Khsrp protein, mouse; D035683:MicroRNAs; C540674:Mirn27 microRNA, mouse; D016328:NF-kappa B; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D015534:Trans-Activators; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II