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Molecular Regulation of Transforming Growth Factor-β1-induced Thioredoxin-interacting Protein Ubiquitination and Proteasomal Degradation in Lung Fibroblasts: Implication in Pulmonary Fibrosis

Journal of Respiratory Biology and Translational Medicine . 2024, 1(1), 10002;
Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
Department of Internal Medicine, The Ohio State University, Columbus, OH, USA
Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
Authors to whom correspondence should be addressed.

Received: 15 Dec 2023    Accepted: 31 Jan 2024    Published: 01 Feb 2024   


Thioredoxin-interacting protein (TXNIP) plays a critical role in regulation of cellular redox reactions and inflammatory responses by interacting with thioredoxin (TRX) or the inflammasome. The role of TXNIP in lung fibrosis and molecular regulation of its stability have not been well studied. Therefore, here we investigated the molecular regulation of TXNIP stability and its role in TGF-β1-mediated signaling in lung fibroblasts. TXNIP protein levels were significantly decreased in lung tissues from bleomycin-challenged mice. Overexpression of TXNIP attenuated transforming growth factor-β1 (TGF-β1)-induced phosphorylation of Smad2/3 and fibronectin expression in lung fibroblasts, suggesting that decrease in TXNIP may contribute to the pathogenesis of lung fibrosis. Further, we observed that TGF-β1 lowered TXNIP protein levels, while TXNIP mRNA levels were unaltered by TGF-β1 exposure. TGF-β1 induced TXNIP degradation via the ubiquitin-proteasome system. A serine residue mutant (TNXIP-S308A) was resistant to TGF-β1-induced degradation. Furthermore, downregulation of ubiquitin-specific protease-13 (USP13) promoted the TGF-β1-induced TXNIP ubiquitination and degradation. Mechanistic studies revealed that USP13 targeted and deubiquitinated TXNIP. The results of this study revealed that the decrease of TXNIP in lungs apparently contributes to the pathogenesis of pulmonary fibrosis and that USP13 can target TXNP for deubiquitination and regulate its stability.


Noble PW, Barkauskas CE, Jiang D. Pulmonary fibrosis: Patterns and perpetrators. J. Clin. Invest. 2012, 122, 2756–2762. [Google Scholar]
Kropski JA, Blackwell TS. Progress in Understanding and Treating Idiopathic Pulmonary Fibrosis. Annu. Rev. Med. 2019, 70, 211–224. [Google Scholar]
Zheng Z, Peng F, Zhou Y. Pulmonary fibrosis: A short- or long-term sequelae of severe COVID-19? Chin. Med. J. Pulm. Crit. Care Med. 2023, 1, 77–83. [Google Scholar]
Ye Z, Hu Y. TGF‑beta1: Gentlemanly orchestrator in idiopathic pulmonary fibrosis (Review). Int. J. Mol. Med. 2021, 48, 132. [Google Scholar]
Fernandez IE, Eickelberg O. The impact of TGF-beta on lung fibrosis: from targeting to biomarkers. Proc. Am. Thorac. Soc. 2012, 9, 111–116. [Google Scholar]
Li S, Zhao J, Shang D, Kass DJ, Zhao Y. Ubiquitination and deubiquitination emerge as players in idiopathic pulmonary fibrosis pathogenesis and treatment. JCI Insight 2018, 3, e120362. [Google Scholar]
Han S, Wang R, Zhang Y, Li X, Gan Y, Gao F, et al. The role of ubiquitination and deubiquitination in tumor invasion and metastasis. Int. J. Biol. Sci. 2022, 18, 2292–2303. [Google Scholar]
Li S, Ye Q, Wei J, Taleb SJ, Wang H, Zhang Y, et al. Nedd4L suppression in lung fibroblasts facilitates pathogenesis of lung fibrosis. Transl. Res. 2023, 253, 1–7. [Google Scholar]
Yoshihara E, Masaki S, Matsuo Y, Chen Z, Tian H, Yodoi J. Thioredoxin/Txnip: redoxisome, as a redox switch for the pathogenesis of diseases. Front. Immunol. 2014, 4, 514. [Google Scholar]
Spindel ON, World C, Berk BC. Thioredoxin interacting protein: redox dependent and independent regulatory mechanisms. Antioxid. Redox Signal. 2012, 16, 587–596. [Google Scholar]
Jung H, Choi I. Thioredoxin-interacting protein, hematopoietic stem cells, and hematopoiesis. Curr. Opin. Hematol. 2014, 21, 265–270. [Google Scholar]
Choi EH, Park SJ. TXNIP: A key protein in the cellular stress response pathway and a potential therapeutic target. Exp. Mol. Med. 2023, 55, 1348–1356. [Google Scholar]
Zhou R, Tardivel A, Thorens B, Choi I, Tschopp J. Thioredoxin-interacting protein links oxidative stress to inflammasome activation. Nat. Immunol. 2010, 11, 136–140. [Google Scholar]
Chen D, Dang BL, Huang JZ, Chen M, Wu D, Xu ML, et al. MiR-373 drives the epithelial-to-mesenchymal transition and metastasis via the miR-373-TXNIP-HIF1alpha-TWIST signaling axis in breast cancer. Oncotarget 2015, 6, 32701–32712. [Google Scholar]
Zhang P, Wang C, Gao K, Wang D, Mao J, An J, et al. The ubiquitin ligase itch regulates apoptosis by targeting thioredoxin-interacting protein for ubiquitin-dependent degradation. J. Biol. Chem. 2010, 285, 8869–8879. [Google Scholar]
Otaki Y, Takahashi H, Watanabe T, Funayama A, Netsu S, Honda Y, et al. HECT-Type Ubiquitin E3 Ligase ITCH Interacts With Thioredoxin-Interacting Protein and Ameliorates Reactive Oxygen Species-Induced Cardiotoxicity. J. Am. Heart Assoc. 2016, 5, e002485. [Google Scholar]
Dong S, Wei J, Bowser RK, Chen BB, Mallampalli RK, Miao J, et al. SCF FBXW17 E3 ubiquitin ligase regulates FBXL19 stability and cell migration. J. Cell. Biochem. 2021, 122, 326–334. [Google Scholar]
Ye Q, Taleb SJ, Wang H, Parinandi NL, Kass DJ, Rojas M, et al. Molecular Regulation of Heme Oxygenase-1 Expression by E2F Transcription Factor 2 in Lung Fibroblast Cells: Relevance to Idiopathic Pulmonary Fibrosis. Biomolecules 2022, 12, 1531. [Google Scholar]
Wu X, Wu L, Wu Y, Chen W, Chen J, Gong L, et al. Heme oxygenase-1 ameliorates endotoxin-induced acute lung injury by modulating macrophage polarization via inhibiting TXNIP/NLRP3 inflammasome activation. Free Radic. Biol. Med. 2023, 194, 12–22. [Google Scholar]
Waldhart AN, Dykstra H, Peck AS, Boguslawski EA, Madaj ZB, Wen J, et al. Phosphorylation of TXNIP by AKT Mediates Acute Influx of Glucose in Response to Insulin. Cell Rep. 2017, 19, 2005–2013. [Google Scholar]
Gregory AD, Tran KC, Tamaskar AS, Wei J, Zhao J, Zhao Y. USP13 Deficiency Aggravates Cigarette-smoke-induced Alveolar Space Enlargement. Cell Biochem. Biophys. 2021, 79, 485–491. [Google Scholar]
Labbadia J, Morimoto RI. The biology of proteostasis in aging and disease. Annu. Rev. Biochem. 2015, 84, 435–464. [Google Scholar]
Hanna J, Guerra-Moreno A, Ang J, Micoogullari Y. Protein Degradation and the Pathologic Basis of Disease. Am. J. Pathol. 2019, 189, 94–103. [Google Scholar]
Mevissen TET, Komander D. Mechanisms of Deubiquitinase Specificity and Regulation. Annu. Rev. Biochem. 2017, 86, 159–192. [Google Scholar]
He Q, Li Y, Zhang W, Chen J, Deng W, Liu Q, et al. Role and mechanism of TXNIP in ageing-related renal fibrosis. Mech. Ageing Dev. 2021, 196, 111475. [Google Scholar]
Wu M, Li R, Hou Y, Song S, Han W, Chen N, et al. Thioredoxin-interacting protein deficiency ameliorates kidney inflammation and fibrosis in mice with unilateral ureteral obstruction. Lab. Invest. 2018, 98, 1211–1224. [Google Scholar]
Park HS, Song JW, Park JH, Lim BK, Moon OS, Son HY, et al. TXNIP/VDUP1 attenuates steatohepatitis via autophagy and fatty acid oxidation. Autophagy 2021, 17, 2549–2564. [Google Scholar]
Chen J, Hui ST, Couto FM, Mungrue IN, Davis DB, Attie AD, et al. Thioredoxin-interacting protein deficiency induces Akt/Bcl-xL signaling and pancreatic beta-cell mass and protects against diabetes. FASEB J. 2008, 22, 3581–3594. [Google Scholar]
Han YY, Gu X, Yang CY, Ji HM, Lan YJ, Bi YQ, et al. Protective effect of dimethyl itaconate against fibroblast-myofibroblast differentiation during pulmonary fibrosis by inhibiting TXNIP. J. Cell. Physiol. 2021, 236, 7734–7744. [Google Scholar]
Wei J, Shi Y, Hou Y, Ren Y, Du C, Zhang L, et al. Knockdown of thioredoxin-interacting protein ameliorates high glucose-induced epithelial to mesenchymal transition in renal tubular epithelial cells. Cell Signal. 2013, 25, 2788–2796. [Google Scholar]
Masaki S, Masutani H, Yoshihara E, Yodoi J. Deficiency of thioredoxin binding protein-2 (TBP-2) enhances TGF-beta signaling and promotes epithelial to mesenchymal transition. PLoS ONE 2012, 7, e39900. [Google Scholar]
Kelleher ZT, Wang C, Forrester MT, Foster MW, Marshall HE. ERK-dependent proteasome degradation of Txnip regulates thioredoxin oxidoreductase activity. J. Biol. Chem. 2019, 294, 13336–13343. [Google Scholar]
Zhao J, Wei J, Dong S, Bowser RK, Zhang L, Jacko AM, et al. Destabilization of Lysophosphatidic Acid Receptor 1 Reduces Cytokine Release and Protects Against Lung Injury. EBioMed 2016, 10, 195–203. [Google Scholar]
Shi S, Pan X, Chen M, Zhang L, Zhang S, Wang X, et al. USP5 promotes lipopolysaccharide-induced apoptosis and inflammatory response by stabilizing the TXNIP protein. Hepatol. Commun. 2023, 7, e1093. [Google Scholar]
Liao X, Li Y, Liu J, Zhang Y, Tan J, Kass DJ, et al. Deubiquitinase USP13 promotes extracellular matrix expression by stabilizing Smad4 in lung fibroblast cells. Transl. Res. 2020, 223, 15–24. [Google Scholar]
Li L, Wei J, Li S, Jacko AM, Weathington, NM, Mallampalli RK, et al. The deubiquitinase USP13 stabilizes the anti-inflammatory receptor IL-1R8/Sigirr to suppress lung inflammation. EBioMed 2019, 45, 553–562. [Google Scholar]
He J, Baoyinna B, Taleb SJ, Zhao J, Zhao Y. USP13 regulates cell senescence through mediating MDM2 stability. Life Sci. 2023, 331, 122044. [Google Scholar]
Yeh HM, Yu CY, Yang HC, Ko SH, Liao CL, Lin YL. Ubiquitin-specific protease 13 regulates IFN signaling by stabilizing STAT1. J. Immunol. 2013, 191, 3328–3336. [Google Scholar]
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