Dataset Information

IL6-regulated CDk8-mediated phosphoproteome of human primary Th1 cells

ABSTRACT: Cytokines are highly pleiotropic ligands that critically contribute to a balanced immune response. We have an incomplete understanding of how cytokines elicit their functional pleiotropy, which has limited their therapeutic efficacy. Here, using Interleukin-6 (IL-6) as a model system, we have performed detailed phosphoproteomic and transcriptomic studies in human CD4 + T helper (Th)-1 cells to address the molecular bases defining cytokine functional pleiotropy. We have identified cyclin dependent kinase (CDK)8 as a new negative regulator of transcriptional activities of signal transducer and activator of transcription (STAT)3. We found that CDK8 is a major regulator of the IL-6 phosphoproteome and interacts with STAT3 in the nucleus upon IL-6 stimulation. Inhibition of CDK8 activity, using specific small molecules inhibitors, reduced the IL-6-induced phosphoproteome by 23% in Th-1 cells, including STAT3 S727 phosphorylation. STAT3 binding to target DNA sites in the genome was increased upon CDK8 inhibition, which resulted in a concomitant increase in STAT3 mediated transcriptional activity. Importantly, inhibition of CDK8 activity under Th-17 polarizing conditions resulted in an enhancement of Th-17 differentiation. Our results support a model where CDK8 regulates STAT3 transcriptional processivity via modulation of its gene loci resident time, critically contributing to diversification of IL-6 responses.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): T Cell, Blood

SUBMITTER: Jonathan Martinez Fabregas

LAB HEAD: Ignacio Moraga Gonzalez

PROVIDER: PXD020964 | Pride | 2020-12-23

REPOSITORIES: Pride

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Publications

CDK8 Fine-Tunes IL-6 Transcriptional Activities by Limiting STAT3 Resident Time at the Gene Loci.

Martinez-Fabregas Jonathan J Wang Luopin L Pohler Elizabeth E Cozzani Adeline A Wilmes Stephan S Kazemian Majid M Mitra Suman S Moraga Ignacio I

Cell reports 20201201 12

Cytokines are highly pleiotropic ligands that regulate the immune response. Here, using interleukin-6 (IL-6) as a model system, we perform detailed phosphoproteomic and transcriptomic studies in human CD4<sup>+</sup> T helper 1 (Th-1) cells to address the molecular bases defining cytokine functional pleiotropy. We identify CDK8 as a negative regulator of STAT3 transcriptional activities, which interacts with STAT3 upon IL-6 stimulation. Inhibition of CDK8 activity, using specific small molecule ...[more]

PMID: 33357429

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Project description:Follicular T helper cells (Tfh) are critical for providing help to B cells for germinal center (GC) formation. Mutations affecting SAP prevent GC formation due to defective T:B cell interactions, yet effects on Tfh cell differentiation remain unclear. We describe the in vitro differentiation of functionally competent “Tfh-like” cells that expressed IL-21, Tfh markers, and Bcl6, and rescued GC formation in SAP-deficient hosts substantially better than other T helper (Th) cells. SAP-deficient Tfh-like cells appeared virtually indistinguishable from wildtype, yet failed to support GCs in vivo. Interestingly, both Tfh-like and in vivo-derived Tfh cells could produce effector cytokines in response to polarizing conditions. Moreover, other Th cell populations could be reprogrammed to obtain Tfh characteristics. ChIP-Seq analyses revealed positive epigenetic markings on Tbx21, Gata3 and Rorc in Tfh-like and ex vivo Tfh cells, and Bcl6 in other Th cells, supporting the concept of plasticity between Tfh and other Th populations. We describe the in vitro differentiation of functionally competent IL-21-producing cells with Tfh-like properties. Importantly, transfer of low numbers of these cells induced GC formation in SAP-deficient hosts more effectively than other in vitro differentiated Th cells, suggesting they represent bona fide Tfh cell precursors. We have chosen the name “Tfh-like” cells for these in vitro differentiated IL-21 producing cells as they exhibit Tfh characteristics, but do not reside within B cell follicles. SAP-deficient Tfh-like cells were virtually indistinguishable from WT, yet nonetheless, failed to effectively contribute to Tfh cells and rescue GC formation in vivo. Evaluation of cytokine production as well as epigenetic chromatin modifications of genes encoding Th cell-specific transcription factors from either in vitro-generated Tfh-like cells or Tfh cells isolated directly ex vivo provided evidence for plasticity between Tfh-like and other Th cell populations. Our results provide insight into the requirements for differentiation and plasticity of Tfh cells, which are critical for the generation of effective long-term humoral immunity. RNA was prepared from subconfluent asynchronously proliferating cells using TRIZOL and purified by RNeasy MinElute Cleanup kit (Qiagen). Hybridization to Affymetrix GeneChip Mouse Genome 430 2.0 arrays was used to generate gene expression profiles of WT Tfh-like and SAP-deficient Tfh-like cells.

Dataset Information

IL6-regulated CDk8-mediated phosphoproteome of human primary Th1 cells

Publications

CDK8 Fine-Tunes IL-6 Transcriptional Activities by Limiting STAT3 Resident Time at the Gene Loci.

Similar Datasets

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