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Wu X, Tommasi di Vignano A, Zhou Q, Michel-Dziunycz PJ, Bai F, Mi J, Qin J, Zu T, Hofbauer GFL. The ARE-binding protein Tristetraprolin (TTP) is a novel target and mediator of calcineurin tumor suppressing function in the skin. PLoS Genet 2018; 14:e1007366. [PMID: 29723192 PMCID: PMC5953486 DOI: 10.1371/journal.pgen.1007366] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 05/15/2018] [Accepted: 04/16/2018] [Indexed: 01/12/2023] Open
Abstract
An increased incidence of skin inflammatory diseases is frequently observed in organtransplanted patients being treated with calcineurin inhibitor-based immunosuppressive agents. The mechanism of increased skin inflammation in this context has however not yet been clarified. Here we report an increased inflammation following inhibition of calcineurin signaling seen in both chemically induced mouse skin tumors and in tumors grafted from H-rasV12 expressing primary human keratinocytes (HKCs). Following UVB or TPA treatment, we specifically found that deletion of the calcineurin gene in mouse keratinocytes (MKCs) resulted in increased inflammation, and this was accompanied by the enhanced production of pro-inflammatory cytokines, such as TNFα, IL-8 and CXCL1. Furthermore, expression of the RNA-binding protein, tristetraprolin (TTP) was down-regulated in response to calcineurin inhibition, wherein TTP was shown to negatively regulate the production of pro-inflammatory cytokines in keratinocytes. The induction of TTP following TPA or UVB treatment was attenuated by calcineurin inhibition in keratinocytes, and correspondingly, disruption of calcineurin signaling down-regulated the amounts of TTP in both clinical and H-rasV12-transformed keratinocyte tumor models. Our results further demonstrated that calcineurin positively controls the stabilization of TTP in keratinocytes through a proteasome-dependent mechanism. Reducing the expression of TTP functionally promoted tumor growth of H-rasV12 expressing HKCs, while stabilizing TTP expression counteracted the tumor-promoting effects of calcineurin inhibition. Collectively these results suggest that calcineurin signaling, acting through TTP protein level stabilization, suppresses keratinocyte tumors by downregulating skin inflammation.
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Affiliation(s)
- Xunwei Wu
- Laboratory for Tissue Engineering and Regeneration and Shandong Provincial Key Laboratory of Oral Tissue Regeneration, School of Stomatology, Shandong University, Jinan, Shandong, China
- Cutaneous Biology Research Centre, Massachusetts General Hospital, Charlestown, MA, United States of America
- * E-mail:
| | - Alice Tommasi di Vignano
- Cutaneous Biology Research Centre, Massachusetts General Hospital, Charlestown, MA, United States of America
| | - Qian Zhou
- Laboratory for Tissue Engineering and Regeneration and Shandong Provincial Key Laboratory of Oral Tissue Regeneration, School of Stomatology, Shandong University, Jinan, Shandong, China
| | | | - Fuxiang Bai
- Laboratory for Tissue Engineering and Regeneration and Shandong Provincial Key Laboratory of Oral Tissue Regeneration, School of Stomatology, Shandong University, Jinan, Shandong, China
| | - Jun Mi
- Laboratory for Tissue Engineering and Regeneration and Shandong Provincial Key Laboratory of Oral Tissue Regeneration, School of Stomatology, Shandong University, Jinan, Shandong, China
| | - Jing Qin
- Laboratory for Tissue Engineering and Regeneration and Shandong Provincial Key Laboratory of Oral Tissue Regeneration, School of Stomatology, Shandong University, Jinan, Shandong, China
| | - Tingjian Zu
- Laboratory for Tissue Engineering and Regeneration and Shandong Provincial Key Laboratory of Oral Tissue Regeneration, School of Stomatology, Shandong University, Jinan, Shandong, China
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