title: A functional genomics screen for microRNA regulators of NF-kappaB signaling.
abstract: BACKGROUND
  The nuclear factor-KappaB (NF-κB) pathway is conserved from fruit flies to humans and is a key mediator of inflammatory signaling. Aberrant regulation of NF-κB is associated with several disorders including autoimmune disease, chronic inflammation, and cancer, making the NF-κB pathway an attractive therapeutic target. Many regulatory components of the NF-κB pathway have been identified, including microRNAs (miRNAs). miRNAs are small non-coding RNAs and are common components of signal transduction pathways. Here we present a cell-based functional genomics screen to systematically identify miRNAs that regulate NF-κB signaling.
  
  
  RESULTS
  We screened a library of miRNA mimics using a NF-κB reporter cell line in the presence and absence of tumor necrosis factor (+/- TNF). There were 9 and 15 hits in the -TNF and +TNF screens, respectively. We identified putative functional targets of these hits by integrating computational predictions with NF-κB modulators identified in a previous genome-wide cDNA screen. miR-517a and miR-517c were the top hits, activating the reporter 86- and 126-fold, respectively. Consistent with these results, miR-517a/c induced the expression of endogenous NF-κB targets and promoted the nuclear localization of p65 and the degradation of IκB. We identified TNFAIP3 interacting protein1 (TNIP1) as a target and characterized a functional SNP in the miR-517a/c binding site. Lastly, miR-517a/c induced apoptosis in vitro, which was phenocopied by knockdown of TNIP1.
  
  
  CONCLUSIONS
  Our study suggests that miRNAs are common components of NF-κB signaling and miR-517a/c may play an important role in linking NF-κB signaling with cell survival through TNIP1.
authors: Genomics and Computational Biology Graduate Group, 1420 Blockley Hall, 423 Guardian Drive, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
authors: Anthony O
authors: AO
authors: Olarerin-George
authors: Lauren
authors: L
authors: Anton
authors: Yih-Chii
authors: YC
authors: Hwang
authors: Michal A
authors: MA
authors: Elovitz
authors: John B
authors: JB
authors: Hogenesch
mesh_terms: D017209:Apoptosis; D002460:Cell Line; D023281:Genomics; D006801:Humans; D035683:MicroRNAs / Q000502:physiology*; D016328:NF-kappa B / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D035683:MicroRNAs; D016328:NF-kappa B