Abstract
Ciprofloxacin use may be associated with adverse aortic events. However, the mechanism underlying the effect of ciprofloxacin on the progression of thoracic aortic aneurysm (TAA) is not well understood. Using an in vitro microphysiological model, we treated human aortic smooth muscle cells (HASMCs) derived from patients with bicuspid aortic valve– or tricuspid aortic valve–associated (BAV- or TAV-associated) TAAs with ciprofloxacin. TAA C57BL/6 mouse models were utilized to verify the effects of ciprofloxacin exposure. In the microphysiological model, real-time PCR, Western blotting, and RNA sequencing showed that ciprofloxacin exposure was associated with a downregulated contractile phenotype, an upregulated inflammatory reaction, and extracellular matrix (ECM) degradation in the normal HASMCs derived from the nondiseased aorta. Ciprofloxacin induced mitochondrial dysfunction in the HASMCs and further increased apoptosis by activating the ERK1/2 and P38 mitogen–activated protein kinase pathways. These adverse effects appeared to be more severe in the HASMCs derived from BAV- and TAV-associated TAAs than in the normal HASMCs when the ciprofloxacin concentration exceeded 100 μg/mL. In the aortic walls of the TAA-induced mice, ECM degradation and apoptosis were aggravated after ciprofloxacin exposure. Therefore, ciprofloxacin should be used with caution in patients with BAV- or TAV-associated TAAs.
Authors
Bitao Xiang, Mieradilijiang Abudupataer, Gang Liu, Xiaonan Zhou, Dingqian Liu, Shichao Zhu, Yang Ming, Xiujie Yin, Shiqiang Yan, Yongxin Sun, Hao Lai, Chunsheng Wang, Jun Li, Kai Zhu
Abstract
Type 1 diabetes (T1D) is an autoimmune disease resulting in pancreatic β cell destruction. Coxsackievirus B3 (CVB3) infection and melanoma differentiation-associated protein 5–dependent (MDA5-dependent) antiviral responses are linked with T1D development. Mutations within IFIH1, coding for MDA5, are correlated with T1D susceptibility, but how these mutations contribute to T1D remains unclear. Utilizing nonobese diabetic (NOD) mice lacking Ifih1 expression (KO) or containing an in-frame deletion within the ATPase site of the helicase 1 domain of MDA5 (ΔHel1), we tested the hypothesis that partial or complete loss-of-function mutations in MDA5 would delay T1D by impairing proinflammatory pancreatic macrophage and T cell responses. Spontaneous T1D developed in female NOD and KO mice similarly, but was significantly delayed in ΔHel1 mice, which may be partly due to a concomitant increase in myeloid-derived suppressor cells. Interestingly, KO male mice had increased spontaneous T1D compared with NOD mice. Whereas NOD and KO mice developed CVB3-accelerated T1D, ΔHel1 mice were protected partly due to decreased type I IFNs, pancreatic infiltrating TNF+ macrophages, IFN-γ+CD4+ T cells, and perforin+CD8+ T cells. Furthermore, ΔHel1 MDA5 protein had reduced ATP hydrolysis compared with wild-type MDA5. Our results suggest that dampened MDA5 function delays T1D, yet loss of MDA5 promotes T1D.
Authors
Samuel I. Blum, Jared P. Taylor, Jessie M. Barra, Ashley R. Burg, Qiao Shang, Shihong Qiu, Oren Shechter, Aleah R. Hayes, Todd J. Green, Aron M. Geurts, Yi-Guang Chen, Hubert M. Tse
Abstract
Medium-chain triglycerides (MCTs), which consist of medium-chain fatty acids (MCFAs), are unique forms of dietary fat with various health benefits. G protein–coupled 84 (GPR84) acts as a receptor for MCFAs (especially C10:0 and C12:0); however, GPR84 is still considered an orphan receptor, and the nutritional signaling of endogenous and dietary MCFAs via GPR84 remains unclear. Here, we showed that endogenous MCFA-mediated GPR84 signaling protected hepatic functions from diet-induced lipotoxicity. Under high-fat diet (HFD) conditions, GPR84-deficient mice exhibited nonalcoholic steatohepatitis (NASH) and the progression of hepatic fibrosis but not steatosis. With markedly increased hepatic MCFA levels under HFD, GPR84 suppressed lipotoxicity-induced macrophage overactivation. Thus, GPR84 is an immunomodulating receptor that suppresses excessive dietary fat intake–induced toxicity by sensing increases in MCFAs. Additionally, administering MCTs, MCFAs (C10:0 or C12:0, but not C8:0), or GPR84 agonists effectively improved NASH in mouse models. Therefore, exogenous GPR84 stimulation is a potential strategy for treating NASH.
Authors
Ryuji Ohue-Kitano, Hazuki Nonaka, Akari Nishida, Yuki Masujima, Daisuke Takahashi, Takako Ikeda, Akiharu Uwamizu, Miyako Tanaka, Motoyuki Kohjima, Miki Igarashi, Hironori Katoh, Tomohiro Tanaka, Asuka Inoue, Takayoshi Suganami, Koji Hase, Yoshihiro Ogawa, Junken Aoki, Ikuo Kimura
Abstract
Wnt/β-catenin is a developmental signaling pathway that plays a crucial role in driving kidney fibrosis after injury. Activation of β-catenin is presumed to be regulated through the posttranslational protein modification. Little is known about whether β-catenin is also subjected to regulation at the posttranscriptional mRNA level. Here, we report that insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) plays a pivotal role in regulating β-catenin. IGF2BP3 was upregulated in renal tubular epithelium of various animal models and patients with chronic kidney disease. IGF2BP3 not only was a direct downstream target of Wnt/β-catenin but also was obligatory for transducing Wnt signal. In vitro, overexpression of IGF2BP3 in kidney tubular cells induced fibrotic responses, whereas knockdown of endogenous IGF2BP3 prevented the expression of injury and fibrosis markers in tubular cells after Wnt3a stimulation. In vivo, exogenous IGF2BP3 promoted β-catenin activation and aggravated kidney fibrosis, while knockdown of IGF2BP3 ameliorated renal fibrotic lesions after obstructive injury. RNA immunoprecipitation and mRNA stability assays revealed that IGF2BP3 directly bound to β-catenin mRNA and stabilized it against degradation. Furthermore, knockdown of IGF2BP3 in tubular cells accelerated β-catenin mRNA degradation in vitro. These studies demonstrate that IGF2BP3 promotes β-catenin signaling and drives kidney fibrosis, which may be mediated through stabilizing β-catenin mRNA. Our findings uncover a previously underappreciated dimension of the complex regulation of Wnt/β-catenin signaling and suggest a potential target for therapeutic intervention of fibrotic kidney diseases.
Authors
Dongyan Song, Jingyue Shang, Yinyi Long, Menghua Zhong, Li Li, Jiongcheng Chen, Yadie Xiang, Huishi Tan, Haili Zhu, Xue Hong, Fan Fan Hou, Haiyan Fu, Youhua Liu
Abstract
Precision medicine can significantly improve outcomes for patients with cancer, but implementation requires comprehensive characterization of tumor cells to identify therapeutically exploitable vulnerabilities. Here, we describe somatic biallelic TET2 mutations in an elderly patient with acute myeloid leukemia (AML) that was chemoresistant to anthracycline and cytarabine but acutely sensitive to 5′-azacitidine (5′-Aza) hypomethylating monotherapy, resulting in long-term morphological remission. Given the role of TET2 as a regulator of genomic methylation, we hypothesized that mutant TET2 allele dosage affects response to 5′-Aza. Using an isogenic cell model system and an orthotopic mouse xenograft, we demonstrate that biallelic TET2 mutations confer sensitivity to 5′-Aza compared with cells with monoallelic mutations. Our data argue in favor of using hypomethylating agents for chemoresistant disease or as first-line therapy in patients with biallelic TET2-mutated AML and demonstrate the importance of considering mutant allele dosage in the implementation of precision medicine for patients with cancer.
Authors
Friedrich Stölzel, Sarah E. Fordham, Devi Nandana, Wei-Yu Lin, Helen Blair, Claire Elstob, Hayden L. Bell, Brigitte Mohr, Leo Ruhnke, Desiree Kunadt, Claudia Dill, Daniel Allsop, Rachel Piddock, Emmanouela-Niki Soura, Catherine Park, Mohd Fadly, Thahira Rahman, Abrar Alharbi, Manja Wobus, Heidi Altmann, Christoph Röllig, Lisa Wagenführ, Gail L. Jones, Tobias Menne, Graham H. Jackson, Helen J. Marr, Jude Fitzgibbon, Kenan Onel, Manja Meggendorfer, Amber Robinson, Zuzanna Bziuk, Emily Bowes, Olaf Heidenreich, Torsten Haferlach, Sara Villar, Beñat Ariceta, Rosa Ayala Diaz, Steven J. Altschuler, Lani F. Wu, Felipe Prosper, Pau Montesinos, Joaquin Martinez-Lopez, Martin Bornhäuser, James M. Allan
Abstract
Urinary catheterization facilitates urinary tract colonization by E. coli and increases infection risk. Here, we aimed to identify strain-specific characteristics associated with the transition from colonization to infection in catheterized patients. In a single-site study population, we compared E. coli isolates from patients with catheter-associated asymptomatic bacteriuria (CAASB) to those with catheter-associated urinary tract infection (CAUTI). CAUTI isolates were dominated by a phylotype B2 subclade containing the multidrug-resistant ST131 lineage relative to CAASB isolates, which were phylogenetically more diverse. A distinctive combination of virulence-associated genes was present in the CAUTI-associated B2 subclade. Catheter-associated biofilm formation was widespread among isolates and did not distinguish CAUTI from CAASB strains. Preincubation with CAASB strains could inhibit catheter colonization by multiple ST131 CAUTI isolates. Comparative genomic analysis identified a group of variable genes associated with high catheter biofilm formation present in both CAUTI and CAASB strains. Among these, ferric citrate transport (Fec) system genes were experimentally associated with enhanced catheter biofilm formation using reporter and fecA deletion strains. These results are consistent with a variable role for catheter biofilm formation in promoting CAUTI by ST131-like strains or resisting CAUTI by lower-risk strains that engage in niche exclusion.
Authors
Zongsen Zou, Robert F. Potter, William H. McCoy 4th, John A. Wildenthal, George L. Katumba, Peter J. Mucha, Gautam Dantas, Jeffrey P. Henderson
Abstract
Elevated circulating dipeptidyl peptidase-4 (DPP4) is a biomarker for liver disease, but its involvement in gluconeogenesis and metabolic associated fatty liver disease progression remains unclear. Here, we identified that DPP4 in hepatocytes but not TEK receptor tyrosine kinase–positive endothelial cells regulates the local bioactivity of incretin hormones and gluconeogenesis. However, the complete absence of DPP4 (Dpp4–/–) in aged mice with metabolic syndrome accelerates liver fibrosis without altering dyslipidemia and steatosis. Analysis of transcripts from the livers of Dpp4–/– mice displayed enrichment for inflammasome, p53, and senescence programs compared with littermate controls. High-fat, high-cholesterol feeding decreased Dpp4 expression in F4/80+ cells, with only minor changes in immune signaling. Moreover, in a lean mouse model of severe nonalcoholic fatty liver disease, phosphatidylethanolamine N-methyltransferase mice, we observed a 4-fold increase in circulating DPP4, in contrast with previous findings connecting DPP4 release and obesity. Last, we evaluated DPP4 levels in patients with hepatitis C infection with dysglycemia (Homeostatic Model Assessment of Insulin Resistance > 2) who underwent direct antiviral treatment (with/without ribavirin). DPP4 protein levels decreased with viral clearance; DPP4 activity levels were reduced at long-term follow-up in ribavirin-treated patients; but metabolic factors did not improve. These data suggest elevations in DPP4 during hepatitis C infection are not primarily regulated by metabolic disturbances.
Authors
Natasha A. Trzaskalski, Branka Vulesevic, My-Anh Nguyen, Natasha Jeraj, Evgenia Fadzeyeva, Nadya M. Morrow, Cassandra A.A. Locatelli, Nicole Travis, Antonio A. Hanson, Julia R.C. Nunes, Conor O’Dwyer, Jelske N. van der Veen, Ilka Lorenzen-Schmidt, Rick Seymour, Serena M. Pulente, Andrew C. Clément, Angela M. Crawley, René L. Jacobs, Mary-Anne Doyle, Curtis L. Cooper, Kyoung-Han Kim, Morgan D. Fullerton, Erin E. Mulvihill
Abstract
Vascular smooth muscle cells (vSMCs) exert a critical role in sensing and maintaining vascular integrity. These cells abundantly express the low-density lipoprotein receptor–related protein 1 (LRP1), a large endocytic signaling receptor that recognizes numerous ligands, including apolipoprotein E–rich lipoproteins, proteases, and protease-inhibitor complexes. We observed the spontaneous formation of aneurysms in the superior mesenteric artery (SMA) of both male and female mice in which LRP1 was genetically deleted in vSMCs (smLRP1–/– mice). Quantitative proteomics revealed elevated abundance of several proteins in smLRP1–/– mice that are known to be induced by angiotensin II–mediated (AngII-mediated) signaling, suggesting that this pathway was dysregulated. Administration of losartan, an AngII type I receptor antagonist, or an angiotensinogen antisense oligonucleotide to reduce plasma angiotensinogen concentrations restored the normal SMA phenotype in smLRP1–/– mice and prevented aneurysm formation. Additionally, using a vascular injury model, we noted excessive vascular remodeling and neointima formation in smLRP1–/– mice that was restored by losartan administration. Together, these findings reveal that LRP1 regulates vascular integrity and remodeling of the SMA by attenuating excessive AngII-mediated signaling.
Authors
Jackie M. Zhang, Dianaly T. Au, Hisashi Sawada, Michael K. Franklin, Jessica J. Moorleghen, Deborah A. Howatt, Pengjun Wang, Brittany O. Aicher, Brian Hampton, Mary Migliorini, Fenge Ni, Adam E. Mullick, Mashhood M. Wani, Areck A. Ucuzian, Hong S. Lu, Selen C. Muratoglu, Alan Daugherty, Dudley K. Strickland
Abstract
Hepatocellular carcinoma (HCC) is the most common lethal form of liver cancer. Apart from surgical removal and transplantation, other treatments have not yet been well established for patients with HCC. In this study, we found that carboxylesterase 1 (CES1) is expressed at various levels in HCC. We further revealed that blockage of CES1 by pharmacological and genetical approaches leads to altered lipid profiles that are directly linked to impaired mitochondrial function. Mechanistically, lipidomic analyses indicated that lipid signaling molecules, including polyunsaturated fatty acids (PUFAs), which activate PPARα/γ, were dramatically reduced upon CES1 inhibition. As a result, the expression of SCD, a PPARα/γ target gene involved in tumor progression and chemoresistance, was significantly downregulated. Clinical analysis demonstrated a strong correlation between the protein levels of CES1 and SCD in HCC. Interference with lipid signaling by targeting the CES1-PPARα/γ-SCD axis sensitized HCC cells to cisplatin treatment. As a result, the growth of HCC xenograft tumors in NU/J mice was potently slowed by coadministration of cisplatin and CES1 inhibition. Our results, thus, suggest that CES1 is a promising therapeutic target for HCC treatment.
Authors
Gang Li, Xin Li, Iqbal Mahmud, Jazmin Ysaguirre, Baharan Fekry, Shuyue Wang, Bo Wei, Kristin L. Eckel-Mahan, Philip L. Lorenzi, Richard Lehner, Kai Sun
Abstract
Keratin expression dynamically changes in airway basal cells (BCs) after acute and chronic injury, yet the functional consequences of these changes on BC behavior remain unknown. In bronchiolitis obliterans (BO) after lung transplantation, BC clonogenicity declines, which is associated with a switch from keratin15 (Krt15) to keratin14 (Krt14). We investigated these keratins’ roles using Crispr-KO in vitro and in vivo and found that Krt14-KO and Krt15-KO produce contrasting phenotypes in terms of differentiation and clonogenicity. Primary mouse Krt14-KO BCs did not differentiate into club and ciliated cells but had enhanced clonogenicity. By contrast, Krt15-KO did not alter BC differentiation but impaired clonogenicity in vitro and reduced the number of label-retaining BCs in vivo after injury. Krt14, but not Krt15, bound the tumor suppressor stratifin (Sfn). Disruption of Krt14, but not of Krt15, reduced Sfn protein abundance and increased expression of the oncogene dNp63a during BC differentiation, whereas dNp63a levels were reduced in Krt15-KO BCs. Overall, the phenotype of Krt15-KO BCs contrasts with Krt14-KO phenotype and resembles the phenotype in BO with decreased clonogenicity, increased Krt14, and decreased dNp63a expression. This work demonstrates that Krt14 and Krt15 functionally regulate BC behavior, which is relevant in chronic disease states like BO.
Authors
Vitaly Ievlev, Thomas J. Lynch, Kyle W. Freischlag, Caitlyn B. Gries, Anit Shah, Albert C. Pai, Bethany A. Ahlers, Soo Park, John F. Engelhardt, Kalpaj R. Parekh
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