Cell biology
Abstract
Lysyl hydroxylase 2 (LH2) is highly expressed in multiple tumor types and accelerates disease progression by hydroxylating lysine residues on fibrillar collagen telopeptides to generate stable collagen cross links in tumor stroma. Here, we show that a galactosylhydroxylysyl glucosyltransferase (GGT) domain on LH2-modified type-VI collagen (Col6) to promote lung adenocarcinoma (LUAD) growth and metastasis. In tumors generated by LUAD cells lacking LH2 GGT domain activity, stroma was less stiff, and stable types of collagen cross links were reduced. Mass spectrometric analysis of total and glycosylated peptides in parental and GGT-inactive tumor samples identified Col6 chain α3 (Col6a3), a component of the Col6 heterotrimeric molecule, as a candidate LH2 substrate. In gain- and loss-of-function studies, high Col6a3 levels increased tumor growth and metastatic activity and enhanced the proliferative, migratory, and invasive activities of LUAD cells. LH2 coimmunoprecipitated with Col6a3, and LH2 glucosylated Col6 in an in vitro reaction. Glucosylation increased the integrin-binding and promigratory activities of Col6 in LUAD cells. Col6a3 K2049 was deglucosylated in GGT-inactive tumor samples, and mutagenesis of Col6a3 K2049 phenocopied Col6a3 deficiency or LH2 GGT domain inactivation in LUAD cells. Thus, LH2 glucosylates Col6 to drive LUAD progression. These findings show that the GGT domain of LH2 is protumorigenic, identify Col6 as a candidate effector, and provide a rationale to develop pharmacological strategies that target LH2’s GGT domain in cancer cells.
Authors
Shike Wang, Houfu Guo, Reo Fukushima, Masahiko Terajima, Min Liu, Guan-Yu Xiao, Lenka Koudelková, Chao Wu, Xin Liu, Jiang Yu, Emma Burris, Jun Xu, Alvise Schiavinato, William K. Russell, Mitsuo Yamauchi, Xiaochao Tan, Jonathan M. Kurie
Abstract
Mitochondrial dysfunction fuels vascular inflammation and atherosclerosis. Mitochondrial calcium uptake 1 (MICU1) maintains mitochondrial Ca2+ homeostasis. However, the role of MICU1 in vascular inflammation and atherosclerosis remains unknown. Here, we report that endothelial MICU1 prevents vascular inflammation and atherosclerosis by maintaining mitochondrial homeostasis. We observed that vascular inflammation was aggravated in endothelial cell–specific Micu1 knockout mice (Micu1ECKO) and attenuated in endothelial cell–specific Micu1 transgenic mice (Micu1ECTg). Furthermore, hypercholesterolemic Micu1ECKO mice also showed accelerated development of atherosclerosis, while Micu1ECTg mice were protected against atherosclerosis. Mechanistically, MICU1 depletion increased mitochondrial Ca2+ influx, thereby decreasing the expression of the mitochondrial deacetylase sirtuin 3 (SIRT3) and the ensuing deacetylation of superoxide dismutase 2 (SOD2), leading to the burst of mitochondrial reactive oxygen species (mROS). Of clinical relevance, we observed decreased MICU1 expression in the endothelial layer covering human atherosclerotic plaques and in human aortic endothelial cells exposed to serum from patients with coronary artery diseases (CAD). Two-sample Wald ratio Mendelian randomization further revealed that increased expression of MICU1 was associated with decreased risk of CAD and coronary artery bypass grafting (CABG). Our findings support MICU1 as an endogenous endothelial resilience factor that protects against vascular inflammation and atherosclerosis by maintaining mitochondrial Ca2+ homeostasis.
Authors
Lu Sun, Ruixue Leng, Monan Liu, Meiming Su, Qingze He, Zhidan Zhang, Zhenghong Liu, Zhihua Wang, Hui Jiang, Li Wang, Shuai Guo, Yiming Xu, Yuqing Huo, Clint L. Miller, Maciej Banach, Yu Huang, Paul C. Evans, Jaroslav Pelisek, Giovanni G. Camici, Bradford C. Berk, Stefan Offermanns, Junbo Ge, Suowen Xu, Jianping Weng
Abstract
Protein arginine methyl transferases (PRMTs) are generally upregulated in cancers. However, the mechanisms leading to this upregulation and its biological consequences are poorly understood. Here, we identify PRMT5, the main symmetric arginine methyltransferase, as a critical driver of chemoresistance in high-grade serous ovarian cancer (HGSOC). PRMT5 levels and its enzymatic activity are induced in a platinum-resistant (Pt-resistant) state at the protein level. To reveal potential regulators of high PRMT5 protein levels, we optimized intracellular immunostaining conditions and performed unbiased CRISPR screening. We identified Kelch-like ECH-associated protein 1 (KEAP1) as a top-scoring negative regulator of PRMT5. Our mechanistic studies show that KEAP1 directly interacted with PRMT5, leading to its ubiquitin-dependent degradation under normal physiological conditions. At the genomic level, ChIP studies showed that elevated PRMT5 directly interacted with the promoters of stress response genes and positively regulated their transcription. Combined PRMT5 inhibition with Pt resulted in synergistic cellular cytotoxicity in vitro and reduced tumor growth in vivo in Pt-resistant patient-derived xenograft tumors. Overall, the findings from this study identify PRMT5 as a critical therapeutic target in Pt-resistant HGSOC cells and reveal the molecular mechanisms that lead to high PRMT5 levels in Pt-treated and chemo-resistant tumors.
Authors
Harun Ozturk, Fidan Seker-Polat, Neda Abbaszadeh, Yasemin Kingham, Sandra Orsulic, Mazhar Adli
Abstract
Although refrigerated storage slows the metabolism of volunteer donor RBCs, which is essential in transfusion medicine, cellular aging still occurs throughout this in vitro process. Storage-induced microerythrocytes (SMEs) are morphologically-altered senescent RBCs that accumulate during storage and are cleared from circulation following transfusion. However, the molecular and cellular alterations that trigger clearance of this RBC subset remain to be identified. Using a staining protocol that sorts long-stored SMEs (i.e., CFSEhigh) and morphologically-normal RBCs (CFSElow), these in vitro aged cells were characterized. Metabolomics analysis identified depletion of energy, lipid-repair, and antioxidant metabolites in CFSEhigh RBCs. By redox proteomics, irreversible protein oxidation primarily affected CFSEhigh RBCs. By proteomics, 96 proteins, mostly in the proteostasis family, had relocated to CFSEhigh RBC membranes. CFSEhigh RBCs exhibited decreased proteasome activity and deformability; increased phosphatidylserine exposure, osmotic fragility, and endothelial cell adherence; and were cleared from the circulation during human spleen perfusion ex vivo. Conversely, molecular, cellular, and circulatory properties of long-stored CFSElow RBCs resembled those of short-stored RBCs. CFSEhigh RBCs are morphologically and metabolically altered, have irreversibly oxidized and membrane-relocated proteins, and exhibit decreased proteasome activity. In vitro aging during storage selectively alters metabolism and proteostasis in these storage-induced senescent RBCs targeted for clearance.
Authors
Sandy Peltier, Mickaël Marin, Monika Dzieciatkowska, Michaël Dussiot, Micaela Kalani Roy, Johanna Bruce, Louise Leblanc, Youcef Hadjou, Sonia Georgeault, Aurélie Fricot, Camille Roussel, Daniel Stephenson, Madeleine Casimir, Abdoulaye Sissoko, François Paye, Safi Dokmak, Papa Alioune Ndour, Philippe Roingeard, Emilie-Fleur Gautier, Steven L. Spitalnik, Olivier Hermine, Pierre A. Buffet, Angelo D’Alessandro, Pascal Amireault
Abstract
Tumor cells often employ many ways to restrain type I interferon signaling to evade immune surveillance. However, whether cellular amino acid metabolism regulate this process remains unclear and its effects on antitumor immunity are relatively unexplored. Here, we find that asparagine inhibits IFN-I signaling and promotes immune escape in bladder cancer. Depletion of asparagine synthetase (ASNS) strongly limits in vivo tumor growth in a CD8+ T cell-dependent manner and boosts immunotherapy efficacy. Moreover, clinically approved ASNase synergizes with anti-PD-1 therapy in suppressing tumor growth. Mechanistically, asparagine can directly bind to RIG-I and facilitate CBL-mediated RIG-I degradation, thereby suppressing IFN signaling and antitumor immune responses. Clinically, tumors with higher ASNS expression show decreased responsiveness to ICIs therapy. Together, our findings uncover asparagine as a natural metabolite to modulate RIG-I-mediated IFN-I signaling, providing the basis for developing the combinatorial use of ASNase and anti-PD-1 for bladder cancer.
Authors
Wenjie Wei, Hongzhao Li, Shuo Tian, Chi Zhang, Junxiao Liu, Wen Tao, Tianwei Cai, Yuhao Dong, Chuang Wang, Dingyi Lu, Yakun Ai, Wanlin Zhang, Hanfeng Wang, Kan Liu, Yang Fan, Yu Gao, Qingbo Huang, Xin Ma, Baojun Wang, Xu Zhang, Yan Huang
Abstract
Super-enhancers (SEs) are expansive cis-regulatory elements known for amplifying oncogene expression across various cancers. However, their role in cervical cancer (CC), a remarkable global malignancy affecting women, remains underexplored. Here we applied integrated epigenomic and transcriptomic profiling to delineate the distinct SE landscape in CC by analyzing paired tumor and normal tissues. Our study identifies a tumor-specific SE at the EFNA1 locus that drives EFNA1 expression in CC. Mechanically, the EFNA1 SE region contains consensus sequences for the transcription factor FOSL2, whose knockdown markedly suppressed luciferase activity and diminished H3K27ac enrichment within the SE region. Functional analyses further underlined EFNA1’s oncogenic role in CC, linking its overexpression to poor patient outcomes. EFNA1 knockdown strikingly reduced CC cell proliferation, migration, and tumor growth. Moreover, EFNA1 cis-interacted with its receptor EphA2, leading to decreased EphA2 tyrosine phosphorylation and subsequent activation of the Src/AKT/STAT3 forward signaling pathway. Inhibition of this pathway with specific inhibitors substantially attenuated the tumorigenic capacity of EFNA1-overexpressing CC cells in both in vitro and in vivo models. Collectively, our study unveils the critical role of SEs in promoting tumor progression through the FOSL2-EFNA1-EphA2-Src/AKT/STAT3 axis, providing new prognostic and therapeutic avenues for CC patients.
Authors
Shu-Qiang Liu, Xi-Xi Cheng, Shuai He, Tao Xia, Yi-Qi Li, Wan Peng, Ya-Qing Zhou, Zi-Hao Xu, Mi-Si He, Yang Liu, Pan-Pan Wei, Song-Hua Yuan, Chang Liu, Shu-Lan Sun, Dong-Ling Zou, Min Zheng, Chun-Yan Lan, Chun-Ling Luo, Jin-Xin Bei
Abstract
Constitutively active mutations of KRAS are prevalent in non-small cell lung cancer (NSCLC). However, the relationship between these mutations and resistance to platinum-based chemotherapy and the underlying mechanisms remain elusive. In this study, we demonstrated that KRAS mutants confer resistance to platinum in NSCLC. Mechanistically, KRAS mutants mediate platinum resistance in NSCLC cells by activating ERK/JNK signaling, which inhibits ALKBH5 m6A demethylase activity by regulating post-translational modifications (PTMs) of ALKBH5. Consequently, the KRAS mutant leads to a global increase in m6A methylation of mRNAs, particularly DDB2 and XPC, which are essential for nucleotide excision repair. This methylation stabilized the mRNA of these two genes, thus enhancing NSCLC cells’ ability to repair platinum-induced DNA damage and avoid apoptosis, thereby contributing to drug resistance. Furthermore, blocking KRAS-mutant-induced m6A methylation, either by overexpressing a SUMOylation-deficient mutant of ALKBH5, or by inhibiting METTL3 pharmacologically, significantly sensitizes KRAS-mutant NSCLC cells to platinum drugs in vitro and in vivo. Collectively, our study uncovers a previously unrecognized mechanism that mediates KRAS mutant-induced chemoresistance in NSCLC cells by activating DNA repair through the modulation of the ERK/JNK/ALKBH5 PTMs-induced m6A modification in DNA damage repair-related genes.
Authors
Fang Yu, Shikan Zheng, Chunjie Yu, Sanhui Gao, Zuqi Shen, Rukiye Nar, Zhexin Liu, Shuang Huang, Lizi Wu, Tongjun Gu, Zhijian Qian
Abstract
Glioblastoma (GBM) is a highly aggressive form of brain tumor characterized by dysregulated metabolism. Increased fatty acid oxidation (FAO) protects tumor cells from lipid peroxidation-induced cell death, although the precise mechanisms involved remain unclear. Herein, we report that loss of tumor necrosis factor receptor-associated factor 3 (TRAF3) in GBM critically regulates lipid peroxidation and tumorigenesis by controlling the oxidation of polyunsaturated fatty acids (PUFAs). TRAF3 is frequently repressed in GBM due to promoter hypermethylation. TRAF3 interacts with enoyl-CoA hydratase 1 (ECH1), an enzyme catalyzing the isomerization of unsaturated fatty acids (UFAs), and mediates K63-linked ubiquitination of ECH1 at Lys214. ECH1 ubiquitination impedes TOMM20-dependent mitochondrial translocation of ECH1, which otherwise promotes the oxidation of UFAs, preferentially the PUFAs, and limits lipid peroxidation. Overexpression of TRAF3 enhances the sensitivity of GBM to ferroptosis and anti-PD-L1 immunotherapy in mice. Thus, the TRAF3-ECH1 axis plays a key role in the metabolism of PUFAs, and is crucial for lipid peroxidation damage and immune elimination in GBM.
Authors
Yu Zeng, Liqian Zhao, Kunlin Zeng, Ziling Zhan, Zhengming Zhan, Shangbiao Li, Hongchao Zhan, Peng Chai, Cheng Xie, Shengfeng Ding, Yuxin Xie, Li Wang, Cuiying Li, Xiaoxia Chen, Daogang Guan, Enguang Bi, Jian-you Liao, Fan Deng, Xiaochun Bai, Ye Song, Aidong Zhou
Abstract
Protein aggregates are emerging therapeutic targets in rare monogenic causes of cardiomyopathy and amyloid heart disease, but their role in more prevalent heart failure syndromes remains mechanistically unexamined. We observed mis-localization of desmin and sarcomeric proteins to aggregates in human myocardium with ischemic cardiomyopathy and in mouse hearts with post-myocardial infarction ventricular remodeling, mimicking findings of autosomal-dominant cardiomyopathy induced by R120G mutation in the cognate chaperone protein, CRYAB. In both syndromes, we demonstrate increased partitioning of CRYAB phosphorylated on serine-59 to NP40-insoluble aggregate-rich biochemical fraction. While CRYAB undergoes phase separation to form condensates, the phospho-mimetic mutation of serine-59 to aspartate (S59D) in CRYAB mimics R120G-CRYAB mutants with reduced condensate fluidity, formation of protein aggregates and increased cell death. Conversely, changing serine to alanine (phosphorylation-deficient mutation) at position 59 (S59A) restored condensate fluidity, and reduced both R120G-CRYAB aggregates and cell death. In mice, S59D CRYAB knock-in was sufficient to induce desmin mis-localization and myocardial protein aggregates, while S59A CRYAB knock-in rescued left ventricular systolic dysfunction post-myocardial infarction and preserved desmin localization with reduced myocardial protein aggregates. 25-Hydroxycholesterol attenuated CRYAB serine-59 phosphorylation and rescued post-myocardial infarction adverse remodeling. Thus, targeting CRYAB phosphorylation-induced condensatopathy is an attractive strategy to counter ischemic cardiomyopathy.
Authors
Moydul Islam, David R. Rawnsley, Xiucui Ma, Walter Navid, Chen Zhao, Xumin Guan, Layla Foroughi, John T. Murphy, Honora Navid, Carla J. Weinheimer, Attila Kovacs, Jessica Nigro, Aaradhya Diwan, Ryan P. Chang, Minu Kumari, Martin E. Young, Babak Razani, Kenneth B. Margulies, Mahmoud Abdellatif, Simon Sedej, Ali Javaheri, Douglas F. Covey, Kartik Mani, Abhinav Diwan
Abstract
Fibrosis of the lower abdominal muscle (LAM) contributes to muscle weakening and inguinal hernia formation, an ailment affecting a noteworthy fifty percent of men by age 75, necessitating surgical correction as the singular therapy. Despite its prevalence, the mechanisms driving LAM fibrosis and hernia development remain poorly understood. Utilizing a humanized mouse model that replicates elevated skeletal muscle tissue estrogen concentrations akin to aging men, we identified estrogen receptor alpha (ESR1) as a key driver of LAM fibroblast proliferation, extracellular matrix deposition, and hernia formation. Fibroblast-specific ESR1 ablation effectively prevented muscle fibrosis and herniation, while pharmacological ESR1 inhibition with fulvestrant reversed hernias and restored normal muscle architecture. Multiomic analyses on in vitro LAM fibroblasts unveiled an estrogen/ESR1-mediated activation of a distinct profibrotic cistrome and gene expression signature, concordant with observations in inguinal hernia tissues in human males. Our findings hold significant promise for prospective medical interventions targeting fibrotic conditions and presenting non-surgical avenues for addressing inguinal hernias.
Authors
Tanvi Potluri, Tianming You, Ping Yin, John S. Coon V, Jonah J. Stulberg, Yang Dai, David J Escobar, Richard L. Lieber, Hong Zhao, Serdar E. Bulun
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ISSN: 0021-9738 (print), 1558-8238 (online)