NF-kB-Dependent Role for Cold-Inducible RNA Binding Protein in Regulating Interleukin 1b

The cold inducible RNA binding protein (CIRBP) responds to a wide array of cellular stresses, including short wavelength ultraviolet light (UVC), at the transcriptional and post-translational level. CIRBP can bind the 3’untranslated region of specific transcripts to stabilize them and facilitate their transport to ribosomes for translation. Here we used RNA interference and oligonucleotide microarrays to identify potential downstream targets of CIRBP induced in response to UVC. Twenty eight transcripts were statistically increased in response to UVC and these exhibited a typical UVC response. Only 5 of the 28 UVCinduced transcripts exhibited a CIRBP-dependent pattern of expression. Surprisingly, 3 of the 5 transcripts (IL1B, IL8 and TNFAIP6) encoded proteins important in inflammation with IL-1b apparently contributing to IL8 and TNFAIP6 expression in an autocrine fashion. UVC-induced IL1B expression could be inhibited by pharmacological inhibition of NFkB suggesting that CIRBP was affecting NF-kB signaling as opposed to IL1B mRNA stability directly. Bacterial lipopolysaccharide (LPS) was used as an activator of NF-kB to further study the potential link between CIRBP and NFkB. Transfection of siRNAs against CIRBP reduced the extent of the LPS-induced phosphorylation of IkBa, NF-kB DNA binding activity and IL-1b expression. The present work firmly establishes a novel link between CIRBP and NF-kB signaling in response to agents with diverse modes of action. These results have potential implications for disease states associated with inflammation. Citation: Brochu C, Cabrita MA, Melanson BD, Hamill JD, Lau R, et al. (2013) NF-kB-Dependent Role for Cold-Inducible RNA Binding Protein in Regulating Interleukin 1b. PLoS ONE 8(2): e57426. doi:10.1371/journal.pone.0057426 Editor: Imed Eddine Gallouzi, McGill University, Canada Received August 30, 2012; Accepted January 21, 2013; Published February 21, 2013 Copyright: 2013 Brochu et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by the Canadian Institutes of Health Research to B.C.M. and M.A.C.P. and funds from the Ottawa Regional Cancer Foundation. C.B. was a recipient of a Cancer Research Society Fellowship, B.D.M. held an Ontario Graduate Scholarship in Science and Technology and B.C.M. was supported with a Research Scientist Award from the National Cancer Institute of Canada supported with funds provided by the Canadian Cancer Society. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: [email protected]