title: IL-32θ downregulates CCL5 expression through its interaction with PKCδ and STAT3.
abstract: Interleukin-32 (IL-32) exists in several isoforms and plays an important role in inflammatory response. Recently, we identified a new isoform, IL-32θ, and performed a microarray analysis to identify IL-32θ-regulated genes in THP-1 myelomonocytic cells. Upon stimulating IL-32θ-expressing THP-1 cells with phorbol myristate acetate (PMA), we found that the CCL5 transcript level was significantly reduced. We confirmed the downregulation of CCL5 protein expression by using an enzyme-linked immunosorbent assay (ELISA). Because STAT3 phosphorylation on Ser727 by PKCδ is reported to suppress CCL5 protein expression, we examined whether IL-32θ-mediated STAT3 Ser727 phosphorylation occurs through an interaction with PKCδ. In this study, we first demonstrate that IL-32θ interacts with PKCδ and STAT3 using co-immunoprecipitation (Co-IP) and pulldown assay. Moreover, STAT3 was rarely phosphorylated on Ser727 in the absence of IL-32θ, leading to the binding of STAT3 to the CCL5 promoter. These results indicate that IL-32θ, through its interaction with PKCδ, downregulates CCL5 expression by mediating the phosphorylation of STAT3 on Ser727 to render it transcriptionally inactive. Therefore, similar to what we have reported for IL-32α and IL-32β, our data from this study suggests that the newly identified IL-32θ isoform also acts as an intracellular modulator of inflammation.
authors.affiliation: Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Neungdong-ro 120, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Yesol
authors.initials: Y
authors.lastname: Bak
authors.affiliation: Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Neungdong-ro 120, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Jeong-Woo
authors.initials: JW
authors.lastname: Kang
authors.affiliation: Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Neungdong-ro 120, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Man Sub
authors.initials: MS
authors.lastname: Kim
authors.affiliation: Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Neungdong-ro 120, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Yun Sun
authors.initials: YS
authors.lastname: Park
authors.affiliation: Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Neungdong-ro 120, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Taeho
authors.initials: T
authors.lastname: Kwon
authors.affiliation: Institute of Biomedical Science and Technology, Konkuk University, Neungdong-ro 120, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Soohyun
authors.initials: S
authors.lastname: Kim
authors.affiliation: College of Pharmacy and Medical Research Center, Chungbuk National University, 12 Gashin-dong, Heungduk-gu, Cheongju, Chungbuk 361-463, Republic of Korea.
authors.forename: Jintae
authors.initials: J
authors.lastname: Hong
authors.affiliation: Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Neungdong-ro 120, Gwangjin-gu, Seoul 143-701, Republic of Korea. Electronic address: ydy4218@konkuk.ac.kr.
authors.forename: Do-Young
authors.initials: DY
authors.lastname: Yoon
mesh_terms: D002460:Cell Line; D018946:Chemokine CCL5 / Q000235:genetics* / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D006801:Humans; D007378:Interleukins / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D010766:Phosphorylation / Q000187:drug effects; D010768:Phosphoserine / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding / Q000187:drug effects; D051745:Protein Kinase C-delta / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D018946:Chemokine CCL5; C496971:IL32 protein, human; D007378:Interleukins; D012333:RNA, Messenger; D050796:STAT3 Transcription Factor; D010768:Phosphoserine; D051745:Protein Kinase C-delta; D013755:Tetradecanoylphorbol Acetate
keywords: CCL5; Interleukin-32θ; Microarray; PKCδ; STAT3