Tripartite motif 13 orchestrates endoplasmic reticulum-associated degradation and endoplasmic reticulum-phagy to modulate dendritic cell-mediated immune responses in sepsis

Abstract

Background: Sepsis is a life-threatening condition characterized by profound immune dysregulation and organ dysfunction. The functional impairment of dendritic cells (DCs) in septic patients is well-documented and contributes significantly to sepsis-induced immunosuppression; yet the underlying mechanisms remain poorly understood. Tripartite motif 13 (TRIM13) has been identified as an immune regulator with predominantly suppressive effects. Here, we aimed to investigate the potential role of TRIM13 restriction in promoting the DC-mediated immune response during sepsis. Methods: Splenic DCs were isolated from wild-type (WT) and DC-specific Trim13 conditional knockout (Trim13 cKO) mice post-cecum ligation and puncture (CLP). These cells were subsequently analyzed by proteomics, immunoblotting, flow cytometry, and transmission electron microscopy (TEM). DC2.4 cells were infected with either Trim13 shRNA or a Trim13 overexpression lentiviral vector and treated with different pharmacological inhibitors. Protein interactions were examined via coimmunoprecipitation (Co-IP) and confocal microscopy. Cytokine levels were measured by enzyme-linked immunosorbent assay (ELISA), and organ lesions were assessed through hematoxylin and eosin (H&E) staining, immunohistochemistry (IHC) for CD45, and TUNEL assays. Results: TRIM13 expression was rapidly upregulated in DCs following septic challenge. Deletion of TRIM13 in DCs disrupted the endoplasmic reticulum (ER)-associated degradation (ERAD) and ER-selective autophagy (ER-phagy)-mediated degradation of the stimulator of interferon genes (STING), leading to sustained STING activation and enhanced DC function. STING signaling promoted the p-IRF3 nuclear translocation, NLRP3 inflammasome priming, and transient DC pyroptosis, thereby exacerbating hyperinflammation in the acute phase of sepsis. Over the longer term, prolonged STING signaling inhibited DCs from adopting the immunosuppressive phenotype and promoting the DC-mediated immune response. Ultimately, TRIM13 deficiency in DCs ameliorated sepsis-induced immunosuppression, preserved organ function in the late phase of sepsis, and reduced overall mortality in septic mice. Conclusions: TRIM13 acts as a key negative regulator of DC function during sepsis. Restricting TRIM13 sustains DC immunostimulatory property, counteracts sepsis-induced immunosuppression, and improves survival outcomes. These findings highlight TRIM13 as a potential therapeutic target for sepsis management.

Keywords

Sepsis / Dendritic cells / Tripartite motif 13 / Endoplasmic reticulum-associated degradation / Endoplasmic reticulum-selective autophagy / Pyroptosis / Stimulator of interferon genes

References

[1] Deutschman Clifford S, Tracey KJ . Sepsis: current dogma and new perspectives. Immunity 2014; 40:463-75. https://doi.org/10.1016/j.immuni.2014.04.001.

[2] Singer M, Deutschman CS, Seymour CW, Shankar-Hari M, Annane D, Bauer M, et al. The third international consensus definitions for sepsis and septic shock (sepsis-3). JAMA 2016; 315:801-10. https://doi.org/10.1001/jama.2016.0287.

[3] Rudd KE, Johnson SC, Agesa KM, Shackelford KA, Tsoi D, Kievlan DR, et al. Global, regional, and national sepsis incidence and mortality, 1990-2017: analysis for the global burden of disease study. Lancet 2020; 395:200-11. https://doi.org/10.1016/s0140-6736(19)32989-7.

[4] Hotchkiss RS, Monneret G, Payen D. Sepsis-induced immunosuppression: from cellular dysfunctions to immunotherapy. Nat Rev Immunol 2013; 13:862-74. https://doi.org/10.1038/nri3552.

[5] Arapis A, Panagiotopoulos D, Giamarellos-Bourboulis EJ. Recent advances of precision immunotherapy in sepsis. Burns Trauma 2025; 13:tkaf001. https://doi.org/10.1093/burnst/tkaf001.

[6] Venet F, Monneret G. Advances in the understanding and treatment of sepsis-induced immunosuppression. Nat Rev Nephrol 2018; 14:121-37. https://doi.org/10.1038/nrneph.2017.165.

[7] Munford RS, Pugin J. Normal responses to injury prevent systemic inflammation and can be immunosuppressive. Am J Respir Crit Care Med 2001; 163:316-21. https://doi.org/10.1164/ajrccm.163.2.2007102.

[8] Wu J, Zhou L, Liu J, Ma G, Kou Q, He Z, et al. The efficacy of thymosin alpha 1 for severe sepsis (etass): a multicenter, single-blind, randomized and controlled trial. Crit Care 2013; 17:R8. https://doi.org/10.1186/cc11932.

[9] Reyes M, Filbin MR, Bhattacharyya RP, Billman K, Eisenhaure T, Hung DT, et al. An immune-cell signature of bacterial sepsis. Nat Med 2020; 26:333-40. https://doi.org/10.1038/s41591-020-0752-4.

[10] Boomer JS, To K, Chang KC, Takasu O, Osborne DF, Walton AH, et al. Immunosuppression in patients who die of sepsis and multiple organ failure. JAMA 2011; 306:2594-605. https://doi.org/10.1001/jama.2011.1829.

[11] van Gent M, Sparrer KMJ, Gack MU. Trim proteins and their roles in antiviral host defenses. Annu Rev Virol 2018; 5:385-405. https://doi.org/10.1146/annurev-virology-092917-043323.

[12] Napolitano LM, Jaffray EG, Hay RT, Meroni G. Functional interactions between ubiquitin e2 enzymes and trim proteins. Biochem J 2011; 434:309-19. https://doi.org/10.1042/BJ20101487.

[13] Li X, Yu Z, Fang Q, Yang M, Huang J, Li Z, et al. The transmembrane endoplasmic reticulum-associated e3 ubiquitin ligase trim13 restrains the pathogenic-DNA-triggered inflammatory response. Sci Adv 2022; 8:eabh0496. https://doi.org/10.1126/sciadv.abh0496.

[14] Dean ST, Ishikawa C, Zhu X, Walulik S, Nixon T, Jordan JK, et al. Repression of trim13 by chromatin assembly factor chaf1b is critical for aml development. Blood Adv 2023; 7:4822-37. https://doi.org/10.1182/bloodadvances.2022009438.

[15] Sun X, Liu L, Wang J, Luo X, Wang M, Wang C, et al. Targeting sting in dendritic cells alleviates psoriatic inflammation by suppressing il-17a production. Cell Mol Immunol 2024; 21:738-51. https://doi.org/10.1038/s41423-024-01160-y.

[16] Lam KC, Araya RE, Huang A, Chen Q, Di Modica M, Rodrigues RR, et al. Microbiota triggers sting-type I IFN-dependent monocyte reprogramming of the tumor microenvironment. Cell 2021; 184:5338-56 e21. https://doi.org/10.1016/j.cell.2021.09.019.

[17] Wang S, Wu Q, Chen T, Su R, Pan C, Qian J, et al. Blocking cd47 promotes antitumour immunity through cd103(+) dendritic cell-NK cell axis in murine hepatocellular carcinoma model. J Hepatol 2022; 77:467-78. https://doi.org/10.1016/j.jhep.2022.03.011.

[18] Jiang L, Ye Y, Han Y, Wang Q, Lu H, Li J, et al. Microplastics dampen the self-renewal of hematopoietic stem cells by disrupting the gut microbiota-hypoxanthine-wnt axis. Cell Discov 2024; 10:35. https://doi.org/10.1038/s41421-024-00665-0.

[19] Wang Z, Sun R, Wang G, Chen Z, Li Y, Zhao Y, et al. Sirt3-mediated deacetylation of prdx3 alleviates mitochondrial oxidative damage and apoptosis induced by intestinal ischemia/reperfusion injury. Redox Biol 2020; 28:101343. https://doi.org/10.1016/j.redox.2019.101343.

[20] Mikawa K, Nishina K, Takao Y, Obara H. Ono-1714, a nitric oxide synthase inhibitor, attenuates endotoxin-induced acute lung injury in rabbits. Anesth Analg 2003; 97:1751-5. https://doi.org/10.1213/01.ANE.0000086896.90343.13.

[21] Eckhoff DE, Bilbao G, Frenette L, Thompson JA, Contreras JL. 17-beta-estradiol protects the liver against warm ischemia/reperfusion injury and is associated with increased serum nitric oxide and decreased tumor necrosis factor-alpha. Surgery 2002; 132:302-9. https://doi.org/10.1067/msy.2002.125718.

[22] Chiu CJ, McArdle AH, Brown R, Scott HJ, Gurd FN. Intestinal mucosal lesion in low-flow states. I. A morphological, hemodynamic, and metabolic reappraisal. Arch Surg 1970; 101:478-83. https://doi.org/10.1001/archsurg.1970.01340280030009.

[23] Decout A, Katz JD, Venkatraman S, Ablasser A. The cgas-sting pathway as a therapeutic target in inflammatory diseases. Nat Rev Immunol 2021; 21:548-69. https://doi.org/10.1038/s41577-021-00524-z.

[24] Rathinam VA, Fitzgerald KA. Inflammasome complexes: emerging mechanisms and effector functions. Cell 2016; 165:792-800. https://doi.org/10.1016/j.cell.2016.03.046.

[25] Ramirez MLG, Poreba M, Snipas SJ, Groborz K, Drag M, Salvesen GS. Extensive peptide and natural protein substrate screens reveal that mouse caspase-11 has much narrower substrate specificity than caspase-1. J Biol Chem 2018; 293:7058-67. https://doi.org/10.1074/jbc.RA117.001329.

[26] Bibo-Verdugo B, Snipas SJ, Kolt S, Poreba M, Salvesen GS . Extended subsite profiling of the pyroptosis effector protein gasdermin d reveals a region recognized by inflammatory caspase-11. J Biol Chem 2020; 295:11292-302. https://doi.org/10.1074/jbc.RA120.014259.

[27] Ji Y, Luo Y, Wu Y, Sun Y, Zhao L, Xue Z, et al. Sel1l-hrd1 endoplasmic reticulum-associated degradation controls sting-mediated innate immunity by limiting the size of the activable sting pool. Nat Cell Biol 2023; 25:726-39. https://doi.org/10.1038/s41556-023-01138-4.

[28] Wang W, Hu D, Wu C, Feng Y, Li A, Liu W, et al. Sting promotes nlrp3 localization in er and facilitates nlrp3 deubiquitination to activate the inflammasome upon hsv-1 infection. PLoS Pathog 2020; 16:e1008335. https://doi.org/10.1371/journal.ppat.1008335.

[29] van der Poll T, van de Veerdonk FL, Scicluna BP, Netea MG. The immunopathology of sepsis and potential therapeutic targets. Nat Rev Immunol 2017; 17:407-20. https://doi.org/10.1038/nri.2017.36.

[30] Torres LK, Pickkers P, van der Poll T. Sepsis-induced immunosuppression. Annu Rev Physiol 2022; 84:157-81. https://doi.org/10.1146/annurev-physiol-061121-040214.

[31] Hu X, Liu T, Zhuang X, Wei L, Gao J. Inhibition of alkbh5 inhibits inflammation and excessive proliferation by promoting trim13 m6a modifications in glomerular mesangial cells. Naunyn Schmiedeberg’s Arch Pharmacol 2024; 397:6779-89. https://doi.org/10.1007/s00210-024-03057-z.

[32] Govatati S, Kumar R, Boro M, Traylor JG Jr, Orr AW, Lusis AJ, et al. Trim13 reduces cholesterol efflux and increases oxidized ldl uptake leading to foam cell formation and atherosclerosis. J Biol Chem 2024; 300:107224. https://doi.org/10.1016/j.jbc.2024.107224.

[33] Xiang Y, Li C, Wang Z, Feng J, Zhang J, Yang Y, et al. Trim13 reduces damage to alveolar epithelial cells in copd by inhibiting endoplasmic reticulum stress-induced er-phagy. Lung 2024; 202:821-30. https://doi.org/10.1007/s00408-024-00753-8.

[34] Zhou P, Zhang Q, Yang Y, Chen D, Jongkaewwattana A, Jin H, et al. Avian trim13 attenuates antiviral innate immunity by targeting mavs for autophagic degradation. Autophagy 2024; 21:754-70. https://doi.org/10.1080/15548627.2024.2426114.

[35] Dejager L, Pinheiro I, Dejonckheere E, Libert C. Cecal ligation and puncture: the gold standard model for polymicrobial sepsis? Trends Microbiol 2011; 19:198-208. https://doi.org/10.1016/j.tim.2011.01.001.

[36] Tomar D, Singh R, Singh AK, Pandya CD, Singh R. Trim13 regulates er stress induced autophagy and clonogenic ability of the cells. Biochim Biophys Acta 2012; 1823:316-26. https://doi.org/10.1016/j.bbamcr.2011.11.015.

[37] Altier C, Garcia-Caballero A, Simms B, You H, Chen L, Walcher J, et al. The cavbeta subunit prevents rfp2-mediated ubiquitination and proteasomal degradation of l-type channels. Nat Neurosci 2011; 14:173-80. https://doi.org/10.1038/nn.2712.

[38] Shindo Y, McDonough JS, Chang KC, Ramachandra M, Sasikumar PG, Hotchkiss RS. Anti-pd-l1 peptide improves survival in sepsis. J Surg Res 2017; 208:33-9. https://doi.org/10.1016/j.jss.2016.08.099.

[39] Chang KC, Burnham CA, Compton SM, Rasche DP, Mazuski RJ, McDonough JS, et al. Blockade of the negative co-stimulatory molecules pd-1 and ctla-4 improves survival in primary and secondary fungal sepsis. Crit Care 2013; 17:R85. https://doi.org/10.1186/cc12711.

[40] Zhang Y, Zhou Y, Lou J, Li J, Bo L, Zhu K, et al. PD-L1 blockade improves survival in experimental sepsis by inhibiting lymphocyte apoptosis and reversing monocyte dysfunction. Crit Care 2010; 14:R220. https://doi.org/10.1186/cc9354.

[41] Wang LX, Ren C, Yao RQ, Luo YN, Yin Y, Wu Y, et al. Sestrin2 protects against lethal sepsis by suppressing the pyroptosis of dendritic cells. Cell Mol Life Sci 2021; 78:8209-27. https://doi.org/10.1007/s00018-021-03970-z.

[42] Li JY, Ren C, Wang LX, Yao RQ, Dong N, Wu Y, et al. Sestrin2 protects dendrite cells against ferroptosis induced by sepsis. Cell Death Dis 2021; 12:834. https://doi.org/10.1038/s41419-021-04122-8.

[43] Wang LX, Zhu XM, Luo YN, Wu Y, Dong N, Tong YL, et al. Sestrin2 protects dendritic cells against endoplasmic reticulum stress-related apoptosis induced by high mobility group box-1 protein. Cell Death Dis 2020; 11:125. https://doi.org/10.1038/s41419-020-2324-4.

[44] Du Q, Luo Y, Xu L, Du C, Zhang W, Xu J, et al. Smart responsive fe/mn nanovaccine triggers liver cancer immunotherapy via pyroptosis and pyroptosis-boosted cgas-sting activation. J Nanobiotechnology 2024; 22:95. https://doi.org/10.1186/s12951-024-02354-2.

[45] Inkol JM, Westerveld MJ, Verburg SG, Walsh SR, Morrison J, Mossman KL, et al. Pyroptosis activates conventional type I dendritic cells to mediate the priming of highly functional anticancer t cells. J Immunother Cancer 2024;12:12. https://doi.org/10.1136/jitc-2023-006781.

[46] Zhang R, Kang R, Tang D. The sting1 network regulates autophagy and cell death. Signal Transduct Target Ther 2021; 6:208. https://doi.org/10.1038/s41392-021-00613-4.

[47] Li N, Zhou H, Wu H, Wu Q, Duan M, Deng W, et al. STING-IRF3 contributes to lipopolysaccharide-induced cardiac dysfunction, inflammation, apoptosis and pyroptosis by activating NLRP3. Redox Biol 2019; 24:101215. https://doi.org/10.1016/j.redox.2019.101215.

[48] Ji CH, Kim HY, Heo AJ, Lee MJ, Park DY, Kim DH, et al. Regulation of reticulophagy by the n-degron pathway. Autophagy 2020; 16:373-5. https://doi.org/10.1080/15548627.2019.1695402.

[49] Levine B, Kroemer G. Biological functions of autophagy genes: a disease perspective. Cell 2019; 176:11-42. https://doi.org/10.1016/j.cell.2018.09.048.

[50] Ji CH, Kim HY, Heo AJ, Lee SH, Lee MJ, Kim SB, et al. The n-degron pathway mediates er-phagy. Mol Cell 2019; 75:1058-72 e9. https://doi.org/10.1016/j.molcel.2019.06.028.

[51] Li Y, Li Y, Yin J, Wang C, Yang M, Gu J, et al. A mitophagy inhibitor targeting p62 attenuates the leukemia-initiation potential of acute myeloid leukemia cells. Cancer Lett 2021; 510:24-36. https://doi.org/10.1016/j.canlet.2021.04.003.

[52] Fasana E, Fregno I, Galli C, Solda T, Molinari M. Er-to-lysosome-associated degradation acts as failsafe mechanism upon erad dysfunction. EMBO Rep 2024; 25:2773-85. https://doi.org/10.1038/s44319-024-00165-y.