title: MKP-1 regulates cytokine mRNA stability through selectively modulation subcellular translocation of AUF1.
abstract: MAPK phosphatase-1 (MKP-1)/dual specificity protein phosphatase-1 (DUSP-1) is a negative regulator of the host inflammatory response to infection. However, the mechanisms underlying the regulation of cytokine expression by MKP-1, especially at the post-transcriptional level, have not been fully delineated. In the current study, MKP-1 specifically dephosphorylated activated MAPK responses and attenuated LPS-induced IL-6, IL-10, and TNF-α expression. In addition, MKP-1 was important in destabilizing cytokine mRNAs. In LPS-stimulated rat macrophages with overexpressed MKP-1, half-lives of IL-6, IL-10 and TNF-α mRNAs were significantly reduced compared to controls. Conversely, half-lives of IL-6, IL-10, and TNF-α mRNAs were significantly increased in bone marrow macrophages derived from MKP-1 knock out (KO) mice compared with macrophages derived from MKP-1 wild type (WT) mice. Furthermore, MKP-1 promoted translocation of RNA-binding protein (RNA-BP) ARE/poly-(U) binding degradation factor 1 (AUF1) from the nucleus to the cytoplasm in response to LPS stimulation as evidenced by Western blot and immunofluorescent staining. Knockdown AUF1 mRNA expression by AUF1 siRNA in MKP-1 WT bone marrow macrophages significantly delayed degradation of IL-6, IL-10 and TNF- α mRNAs compared with controls. Finally, AUF1 was immunoprecipitated with the RNA complex in cellular lysates derived from bone marrow macrophages of MKP-1 KO vs. WT mice, which had increased AUF1-bound target mRNAs, including IL-6, IL-10, and TNF-α in WT macrophages compared with MKP-1 KO macrophages. Thus, this work provides new mechanistic insight of MKP-1 signaling and regulation of cytokine mRNA stability through RNA binding proteins in response to inflammatory stimuli.
authors: Department of Craniofacial Biology and the Center for Oral Health Research, Medical University of South Carolina, SC 29425, United States.
authors: Hong
authors: H
authors: Yu
authors: Yuhao
authors: Y
authors: Sun
authors: Courtney
authors: C
authors: Haycraft
authors: Viswanathan
authors: V
authors: Palanisamy
authors: Keith L
authors: KL
authors: Kirkwood
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D016207:Cytokines / Q000235:genetics / Q000502:physiology*; D054638:Dual Specificity Phosphatase 1 / Q000502:physiology*; D004797:Enzyme-Linked Immunosorbent Assay; D019204:GTP-Binding Proteins / Q000378:metabolism*; D000081035:Heterogeneous Nuclear Ribonucleoprotein D0; D034502:Heterogeneous-Nuclear Ribonucleoprotein D / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D021381:Protein Transport; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D013347:Subcellular Fractions / Q000378:metabolism*
chemical_list: D016207:Cytokines; D000081035:Heterogeneous Nuclear Ribonucleoprotein D0; D034502:Heterogeneous-Nuclear Ribonucleoprotein D; C000630988:Hnrnpd protein, rat; C000630987:Hnrpd protein, mouse; D012333:RNA, Messenger; D054638:Dual Specificity Phosphatase 1; C517020:Dusp1 protein, mouse; D019204:GTP-Binding Proteins