NF-kappaB p65-dependent transactivation of miRNA genes following Cryptosporidium parvum infection stimulates epithelial cell immune responses.
Cryptosporidium parvum is a protozoan parasite that infects the gastrointestinal epithelium and causes diarrheal disease worldwide. Innate epithelial immune responses are key mediators of the host's defense to C. parvum. MicroRNAs (miRNAs) regulate gene expression at the posttranscriptional level and are involved in regulation of both innate and adaptive immune responses. Using an in vitro model of human cryptosporidiosis, we analyzed C. parvum-induced miRNA expression in biliary epithelial cells (i.e., cholangiocytes). Our results demonstrated differential alterations in the mature miRNA expression profile in cholangiocytes following C. parvum infection or lipopolysaccharide stimulation. Database analysis of C. parvum-upregulated miRNAs revealed potential NF-kappaB binding sites in the promoter elements of a subset of miRNA genes. We demonstrated that mir-125b-1, mir-21, mir-30b, and mir-23b-27b-24-1 cluster genes were transactivated through promoter binding of the NF-kappaB p65 subunit following C. parvum infection. In contrast, C. parvum transactivated mir-30c and mir-16 genes in cholangiocytes in a p65-independent manner. Importantly, functional inhibition of selected p65-dependent miRNAs in cholangiocytes increased C. parvum burden. Thus, we have identified a panel of miRNAs regulated through promoter binding of the NF-kappaB p65 subunit in human cholangiocytes in response to C. parvum infection, a process that may be relevant to the regulation of epithelial anti-microbial defense in general.
Zhou
Rui
R
Department of Medical Microbiology and Immunology, Creighton University Medical Center, Omaha, Nebraska, United States of America.
Hu
Guoku
G
Liu
Jun
J
Gong
Ai-Yu
AY
Drescher
Kristen M
KM
Chen
Xian-Ming
XM
D001652:Bile Ducts / Q000166:cytology; D001665:Binding Sites; D045744:Cell Line, Tumor; D003457:Cryptosporidiosis / Q000235:genetics / Q000276:immunology*; D016785:Cryptosporidium parvum / Q000235:genetics / Q000472:pathogenicity*; D004847:Epithelial Cells / Q000276:immunology; D020869:Gene Expression Profiling; D006801:Humans; D008070:Lipopolysaccharides; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic; D051996:Transcription Factor RelA / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
D008070:Lipopolysaccharides; D035683:MicroRNAs; D051996:Transcription Factor RelA