title: Investigation of JAKs/STAT-3 in lipopolysaccharide-induced intestinal epithelial cells.
abstract: Janus-activated kinase (JAKs)-signal transducer and activator of transcription 3 (STAT-3) signalling play critical roles in immunoregulation and immunopathology, which involve inflammatory responses and enteritis. JAK phosphorylates STAT-3 in response to stimulation by cytokines or growth factors, and then activates or represses the gene expression. STAT-3 is activated persistently in cancer cells and contributes to the malignant progression of various types of cancer and inflammation. To elucidate the different roles of JAKs in the activation of STAT-3, the lipopolysaccharide-induced primary intestinal epithelial cell (IEC) acute inflammatory model was established. Small interference RNAs (siRNAs) were then employed to attenuate the expression levels of JAKs. Real-time quantitative reverse transcription-polymerase chain reaction (PCR) (qRT-PCR) revealed that JAK mRNA levels were reduced efficiently by JAK-specific siRNAs. Under the IEC inflammatory model transfected with si-JAK, which equates to effective silencing, qRT-PCR and Western blot assays, suggested that knockdowns of JAK attenuated the JAK-induced down-regulation of STAT-3 at the mRNA or protein levels. In particular, JAK1 played a key role, which was consistent with the RNA-Seq results. Subsequently, the expression levels of proinflammatory cytokines interleukin (IL)-1β and tumour necrosis factor (TNF)-α were down-regulated in the IEC inflammatory model transfected with si-JAK1. JAK1 appears as a direct activator for STAT-3, whereas treatments targeting JAK1 repressed STAT-3 sufficiently pathways in the IEC inflammatory model. Therefore, the control of JAK1 using siRNAs has the potential to be an effective strategy against enteritis.
authors.affiliation: Laboratory Animal Center, Southwest Medical University, Luzhou, China.
authors.forename: L
authors.initials: L
authors.lastname: Fu
authors.affiliation: Laboratory Animal Center, Southwest Medical University, Luzhou, China.
authors.forename: L-W
authors.initials: LW
authors.lastname: Wei
authors.affiliation: Laboratory Animal Center, Southwest Medical University, Luzhou, China.
authors.forename: M-D
authors.initials: MD
authors.lastname: Zhao
authors.affiliation: Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Chengdu, China.
authors.forename: J-L
authors.initials: JL
authors.lastname: Zhu
authors.affiliation: Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Chengdu, China.
authors.forename: S-Y
authors.initials: SY
authors.lastname: Chen
authors.affiliation: Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Chengdu, China.
authors.forename: X-B
authors.initials: XB
authors.lastname: Jia
authors.affiliation: Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Chengdu, China.
authors.forename: S-J
authors.initials: SJ
authors.lastname: Lai
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells; D015870:Gene Expression; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D007413:Intestinal Mucosa / Q000276:immunology* / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000276:immunology*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D011817:Rabbits; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; D034741:RNA, Small Interfering; D050796:STAT3 Transcription Factor; D011494:Protein Kinases
keywords: IECs; JAKs/STAT-3; RNA-Seq; enteritis; siRNA