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So J, Wu D, Tai AK, Lichtenstein AH, Matthan NR, Lamon-Fava S. Monocyte transcriptomic profile following EPA and DHA supplementation in men and women with low-grade chronic inflammation. Atherosclerosis 2024; 388:117407. [PMID: 38091778 PMCID: PMC10872449 DOI: 10.1016/j.atherosclerosis.2023.117407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 11/16/2023] [Accepted: 11/29/2023] [Indexed: 01/15/2024]
Abstract
BACKGROUND Recent data indicate considerable variability in response to very long chain omega-3 fatty acid supplementation on cardiovascular disease risk. This inconsistency may be due to differential effects of EPA vs DHA and/or sex-specific responses. METHODS Sixteen subjects (eight men and eight women) 50-75 y and with low-grade chronic inflammation participated in a randomized controlled crossover trial comparing 3 g/d EPA, 3 g/d DHA, and placebo (3 g/d high oleic acid sunflower oil). Blood monocytes were isolated at the end of each phase for RNA-sequencing. RESULTS Sex dimorphism in monocyte gene expression was observed, therefore, data for men and women were analyzed separately. 1088 genes were differentially expressed in men and 997 in women (p < 0.05). In both men and women, EPA and DHA repressed genes involved in protein turnover and mitochondrial energy metabolism, relative to placebo. In men only, EPA and DHA upregulated genes related to wound healing and PPARα activation. In women only, EPA and DHA activated genes related to ER stress response. Relative to DHA, EPA resulted in lower expression of genes involved in inflammatory processes in men, and lower expression of genes involved in ER stress response in women. CONCLUSIONS EPA and DHA supplementation elicited both similar and differential effects on monocyte transcriptome, some of which were sex specific. The observed variability in response to EPA and DHA in men and women could in part explain the conflicting results from previous cardiovascular clinical trials using omega-3 fatty acids.
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Affiliation(s)
- Jisun So
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA
| | - Dayong Wu
- Nutritional Immunology Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA
| | - Albert K Tai
- Department of Immunology, Tufts University School of Medicine, Boston, MA, USA
| | - Alice H Lichtenstein
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA
| | - Nirupa R Matthan
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA
| | - Stefania Lamon-Fava
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA.
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Forster ER, Yang X, Tai AK, Hang HC, Shen A. Identification of a Bile Acid-Binding Transcription Factor in Clostridioides difficile Using Chemical Proteomics. ACS Chem Biol 2022; 17:3086-3099. [PMID: 36279369 PMCID: PMC10518218 DOI: 10.1021/acschembio.2c00463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Clostridioides difficile is a Gram-positive anaerobic bacterium that is the leading cause of hospital-acquired gastroenteritis in the US. In the gut milieu, C. difficile encounters microbiota-derived, growth-inhibiting bile acids that are thought to be a significant mechanism of colonization resistance. While the levels of certain bile acids in the gut correlate with susceptibility to C. difficile infection, their molecular targets in C. difficile remain unknown. In this study, we sought to use chemical proteomics to identify bile acid-interacting proteins in C. difficile. Using photoaffinity bile acid probes and chemical proteomics, we identified a previously uncharacterized MerR family protein, CD3583 (now BapR), as a putative bile acid-sensing transcription regulator. Our data indicate that BapR specifically binds to and is stabilized by lithocholic acid (LCA) in C. difficile. Although loss of BapR did not affect C. difficile's sensitivity to LCA, ΔbapR cells elongated more in the presence of LCA compared to wild-type cells. Transcriptomics revealed that BapR regulates several gene clusters, with the expression of the mdeA-cd3573 locus being specifically de-repressed in the presence of LCA in a BapR-dependent manner. Electrophoretic mobility shift assays revealed that BapR directly binds to the mdeA promoter region. Because mdeA is involved in amino acid-related sulfur metabolism and the mdeA-cd3573 locus encodes putative transporters, we propose that BapR senses a gastrointestinal tract-specific small molecule, LCA, as an environmental cue for metabolic adaptation.
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Affiliation(s)
- Emily R Forster
- Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts 02111, United States
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, United States
| | - Xinglin Yang
- Department of Immunology and Microbiology, Scripps Research, La Jolla, California 92037, United States
| | - Albert K Tai
- Department of Immunology, Tufts University School of Medicine, Boston, Massachusetts 02111, United States
- Data Intensive Studies Center, Tufts University, Medford, Massachusetts 02155, United States
| | - Howard C Hang
- Department of Immunology and Microbiology, Scripps Research, La Jolla, California 92037, United States
- Department of Chemistry, Scripps Research, La Jolla, California 92037, United States
| | - Aimee Shen
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, United States
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3
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Nagpal N, Tai AK, Nandakumar J, Agarwal S. Domain specific mutations in dyskerin disrupt 3' end processing of scaRNA13. Nucleic Acids Res 2022; 50:9413-9425. [PMID: 36018809 PMCID: PMC9458449 DOI: 10.1093/nar/gkac706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 12/06/2021] [Revised: 07/27/2022] [Accepted: 08/10/2022] [Indexed: 12/24/2022] Open
Abstract
Mutations in DKC1 (encoding dyskerin) cause telomere diseases including dyskeratosis congenita (DC) by decreasing steady-state levels of TERC, the non-coding RNA component of telomerase. How DKC1 mutations variably impact numerous other snoRNAs remains unclear, which is a barrier to understanding disease mechanisms in DC beyond impaired telomere maintenance. Here, using DC patient iPSCs, we show that mutations in the dyskerin N-terminal extension domain (NTE) dysregulate scaRNA13. In iPSCs carrying the del37L NTE mutation or engineered to carry NTE mutations via CRISPR/Cas9, but not in those with C-terminal mutations, we found scaRNA13 transcripts with aberrant 3' extensions, as seen when the exoribonuclease PARN is mutated in DC. Biogenesis of scaRNA13 was rescued by repair of the del37L DKC1 mutation by genome-editing, or genetic or pharmacological inactivation of the polymerase PAPD5, which counteracts PARN. Inspection of the human telomerase cryo-EM structure revealed that in addition to mediating intermolecular dyskerin interactions, the NTE interacts with terminal residues of the associated snoRNA, indicating a role for this domain in 3' end definition. Our results provide mechanistic insights into the interplay of dyskerin and the PARN/PAPD5 axis in the biogenesis and accumulation of snoRNAs beyond TERC, broadening our understanding of ncRNA dysregulation in human diseases.
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Affiliation(s)
- Neha Nagpal
- Division of Hematology/Oncology and Stem Cell Program, Boston Children's Hospital; Pediatric Oncology, Dana-Farber Cancer Institute; Harvard Stem Cell Institute; Department of Pediatrics, Harvard Medical School; Manton Center for Orphan Disease Research; Harvard Initiative in RNA Medicine; Boston, MA, USA
| | - Albert K Tai
- Department of Immunology, Tufts University School of Medicine, Boston, MA, USA
- Data Intensive Studies Center, Tufts University, Medford, MA, USA
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Suneet Agarwal
- To whom correspondence should be addressed. Tel: +1 617 919 4610; Fax: +1 617 919 3359;
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Usuelli V, Ben Nasr M, D'Addio F, Liu K, Vergani A, El Essawy B, Yang J, Assi E, Uehara M, Rossi C, Solini A, Capobianco A, Rigamonti E, Potena L, Venturini M, Sabatino M, Bottarelli L, Ammirati E, Frigerio M, Castillo‐Leon E, Maestroni A, Azzoni C, Loretelli C, Joe Seelam A, Tai AK, Pastore I, Becchi G, Corradi D, Visner GA, Zuccotti GV, Chau NB, Abdi R, Pezzolesi MG, Fiorina P. miR-21 antagonism reprograms macrophage metabolism and abrogates chronic allograft vasculopathy. Am J Transplant 2021; 21:3280-3295. [PMID: 33764625 PMCID: PMC8518036 DOI: 10.1111/ajt.16581] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 02/19/2021] [Accepted: 03/09/2021] [Indexed: 01/25/2023]
Abstract
Despite much progress in improving graft outcome during cardiac transplantation, chronic allograft vasculopathy (CAV) remains an impediment to long-term graft survival. MicroRNAs (miRNAs) emerged as regulators of the immune response. Here, we aimed to examine the miRNA network involved in CAV. miRNA profiling of heart samples obtained from a murine model of CAV and from cardiac-transplanted patients with CAV demonstrated that miR-21 was most significantly expressed and was primarily localized to macrophages. Interestingly, macrophage depletion with clodronate did not significantly prolong allograft survival in mice, while conditional deletion of miR-21 in macrophages or the use of a specific miR-21 antagomir resulted in indefinite cardiac allograft survival and abrogated CAV. The immunophenotype, secretome, ability to phagocytose, migration, and antigen presentation of macrophages were unaffected by miR-21 targeting, while macrophage metabolism was reprogrammed, with a shift toward oxidative phosphorylation in naïve macrophages and with an inhibition of glycolysis in pro-inflammatory macrophages. The aforementioned effects resulted in an increase in M2-like macrophages, which could be reverted by the addition of L-arginine. RNA-seq analysis confirmed alterations in arginase-associated pathways associated with miR-21 antagonism. In conclusion, miR-21 is overexpressed in murine and human CAV, and its targeting delays CAV onset by reprogramming macrophages metabolism.
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Affiliation(s)
- Vera Usuelli
- International Center for T1DPediatric Clinical Research Center “Romeo ed Enrica Invernizzi”Department of Biomedical and Clinical Science L. SaccoUniversita Degli Studi di MilanoMilanItaly
| | - Moufida Ben Nasr
- International Center for T1DPediatric Clinical Research Center “Romeo ed Enrica Invernizzi”Department of Biomedical and Clinical Science L. SaccoUniversita Degli Studi di MilanoMilanItaly,Nephrology DivisionBoston Children's HospitalHarvard Medical SchoolBostonMassachusetts
| | - Francesca D'Addio
- International Center for T1DPediatric Clinical Research Center “Romeo ed Enrica Invernizzi”Department of Biomedical and Clinical Science L. SaccoUniversita Degli Studi di MilanoMilanItaly
| | - Kaifeng Liu
- Division of Pulmonary and Respiratory DiseasesBoston Children's HospitalHarvard Medical SchoolBostonMassachusetts
| | - Andrea Vergani
- Nephrology DivisionBoston Children's HospitalHarvard Medical SchoolBostonMassachusetts
| | - Basset El Essawy
- Department of MedicineAl‐Azhar UniversityCairoEgypt,Renal DivisionTransplantation Research CenterBrigham and Women's HospitalHarvard Medical SchoolBostonMassachusetts
| | - Jun Yang
- Institute of Organ TransplantationTongji Hospital and Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Emma Assi
- International Center for T1DPediatric Clinical Research Center “Romeo ed Enrica Invernizzi”Department of Biomedical and Clinical Science L. SaccoUniversita Degli Studi di MilanoMilanItaly
| | - Mayuko Uehara
- Renal DivisionTransplantation Research CenterBrigham and Women's HospitalHarvard Medical SchoolBostonMassachusetts
| | - Chiara Rossi
- Department of Clinical and Experimental MedicineUniversity of PisaPisaItaly
| | - Anna Solini
- Department of SurgicalMedical, Molecular and Critical Area PathologyUniversity of PisaPisaItaly
| | - Annalisa Capobianco
- Division of Immunology, Transplantation and Infectious DiseaseSan Raffaele Scientific InstituteMilanItaly
| | - Elena Rigamonti
- Division of Immunology, Transplantation and Infectious DiseaseSan Raffaele Scientific InstituteMilanItaly
| | - Luciano Potena
- Heart Failure and Heart Transplant ProgramS. Orsola‐Malpighi HospitalAlma‐Mater University of BolognaBolognaItaly
| | | | - Mario Sabatino
- Department of Cardiothoracic, Transplantation and Vascular SurgeryS. Orsola‐Malpighi HospitalAlma Mater‐University of BolognaBolognaItaly
| | | | - Enrico Ammirati
- De Gasperis Cardio Center and Transplant CenterNiguarda HospitalMilanItaly
| | - Maria Frigerio
- De Gasperis Cardio Center and Transplant CenterNiguarda HospitalMilanItaly
| | - Eduardo Castillo‐Leon
- Nephrology DivisionBoston Children's HospitalHarvard Medical SchoolBostonMassachusetts
| | - Anna Maestroni
- International Center for T1DPediatric Clinical Research Center “Romeo ed Enrica Invernizzi”Department of Biomedical and Clinical Science L. SaccoUniversita Degli Studi di MilanoMilanItaly
| | - Cinzia Azzoni
- Department of Medicine and SurgeryUniversity of ParmaParmaItaly
| | - Cristian Loretelli
- International Center for T1DPediatric Clinical Research Center “Romeo ed Enrica Invernizzi”Department of Biomedical and Clinical Science L. SaccoUniversita Degli Studi di MilanoMilanItaly
| | - Andy Joe Seelam
- International Center for T1DPediatric Clinical Research Center “Romeo ed Enrica Invernizzi”Department of Biomedical and Clinical Science L. SaccoUniversita Degli Studi di MilanoMilanItaly
| | - Albert K. Tai
- Tufts University Core Facility (TUCF) Genomics CoreTufts University School of MedicineBostonMassachusetts
| | - Ida Pastore
- Division of EndocrinologyASST Fatebenefratelli‐SaccoMilanItaly
| | | | | | - Gary A. Visner
- Division of Pulmonary and Respiratory DiseasesBoston Children's HospitalHarvard Medical SchoolBostonMassachusetts
| | - Gian V. Zuccotti
- International Center for T1DPediatric Clinical Research Center “Romeo ed Enrica Invernizzi”Department of Biomedical and Clinical Science L. SaccoUniversita Degli Studi di MilanoMilanItaly,Department of PediatricsBuzzi Children's HospitalMilanItaly
| | | | - Reza Abdi
- Renal DivisionTransplantation Research CenterBrigham and Women's HospitalHarvard Medical SchoolBostonMassachusetts
| | - Marcus G. Pezzolesi
- Division of Nephrology and Hypertension, Diabetes and Metabolism CenterUniversity of UtahSalt Lake CityUtah
| | - Paolo Fiorina
- International Center for T1DPediatric Clinical Research Center “Romeo ed Enrica Invernizzi”Department of Biomedical and Clinical Science L. SaccoUniversita Degli Studi di MilanoMilanItaly,Nephrology DivisionBoston Children's HospitalHarvard Medical SchoolBostonMassachusetts,Division of EndocrinologyASST Fatebenefratelli‐SaccoMilanItaly
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So J, Tai AK, Lichtenstein AH, Wu D, Lamon-Fava S. Sexual dimorphism of monocyte transcriptome in individuals with chronic low-grade inflammation. Biol Sex Differ 2021; 12:43. [PMID: 34321081 PMCID: PMC8320037 DOI: 10.1186/s13293-021-00387-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 07/15/2021] [Indexed: 01/29/2023] Open
Abstract
Sexual dimorphism in the immune system is evidenced by a higher prevalence of autoimmune diseases in women and higher susceptibility to infectious diseases in men. However, the molecular basis of these sex-based differences is not fully understood. We have characterized the transcriptome profiles of peripheral blood monocytes from males and postmenopausal females with chronic low-grade inflammation. We identified 41 sexually differentially expressed genes [adjusted p value (FDR) < 0.1], including genes involved in immune cell activation (e.g., CEACAM1, FCGR2B, and SLAMF7) and antigen presentation (e.g., AIM2, CD1E, and UBA1) with a higher expression in females than males. Moreover, signaling pathways of immune or inflammatory responses, including interferon (IFN) signaling [z-score = 2.45, -log(p) = 3.88], were found to be more upregulated in female versus male monocytes, based on a set of genes exhibiting sex-biased expression (p < 0.03). The contribution of IFN signaling to the sexual transcriptional differences was further confirmed by direct comparisons of the monocyte sex-biased genes with IFN signature genes (ISGs) that were previously curated in mouse macrophages. ISGs showed a greater overlap with female-biased genes than male-biased genes and a higher overall expression in female than male monocytes, particularly for the genes of antiviral and inflammatory responses to IFN. Given the role of IFN in immune defense and autoimmunity, our results suggest that sexual dimorphism in immune functions may be associated with more priming of innate immune pathways in female than male monocytes. These findings highlight the role of sex on the human immune transcriptome.
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Affiliation(s)
- Jisun So
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA
| | - Albert K Tai
- Department of Immunology, Tufts University School of Medicine, Boston, MA, USA
| | - Alice H Lichtenstein
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA
| | - Dayong Wu
- Nutritional Immunology Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA
| | - Stefania Lamon-Fava
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA.
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6
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So J, Wu D, Lichtenstein AH, Tai AK, Matthan NR, Maddipati KR, Lamon-Fava S. EPA and DHA differentially modulate monocyte inflammatory response in subjects with chronic inflammation in part via plasma specialized pro-resolving lipid mediators: A randomized, double-blind, crossover study. Atherosclerosis 2020; 316:90-98. [PMID: 33303222 DOI: 10.1016/j.atherosclerosis.2020.11.018] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 10/23/2020] [Accepted: 11/18/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND AND AIMS The independent effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on chronic inflammation through their downstream lipid mediators, including the specialized pro-resolving lipid mediators (SPM), remain unstudied. Therefore, we compared the effects of EPA and DHA supplementation on monocyte inflammatory response and plasma polyunsaturated fatty acids (PUFA) SPM lipidome. METHODS After a 4-week lead-in phase (baseline), 9 men and 12 postmenopausal women (50-75 years) with chronic inflammation received two phases of 10-week supplementation with 3 g/day EPA and DHA in a random order, separated by a 10-week washout. RESULTS Compared with baseline, EPA and DHA supplementation differently modulated LPS-stimulated monocyte cytokine expression. EPA lowered TNFA (p < 0.001) whereas DHA reduced TNFA (p < 0.001), IL6 (p < 0.02), MCP1 (p < 0.03), and IL10 (p < 0.01). DHA lowered IL10 expression relative to EPA (p = 0.03). Relative to baseline, EPA, but not DHA, decreased the ratios of TNFA/IL10 and MCP1/IL10 (both p < 0.01). EPA and DHA also significantly changed plasma PUFA SPM lipidome by replacing n-6 AA derivatives with their respective derivatives including 18-hydroxy-EPA (+5 fold by EPA) and 17- and 14-hydroxy-DHA (+3 folds by DHA). However, DHA showed a wider effect than EPA by also significantly increasing EPA derivatives and DPA-derived SPM at a greater expense of AA derivatives. Different groups of PUFA derivatives mediated the differential effects of EPA and DHA on monocyte cytokine expression. CONCLUSIONS EPA and DHA had distinct effects on monocyte inflammatory response with a broader effect of DHA in attenuating pro-inflammatory cytokines. These differential effects were potentially mediated by different groups of PUFA derivatives, suggesting immunomodulatory activities of SPM and their intermediates.
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Affiliation(s)
- Jisun So
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA
| | - Dayong Wu
- Nutritional Immunology Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA
| | - Alice H Lichtenstein
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA
| | - Albert K Tai
- Department of Immunology, Tufts University School of Medicine, Boston, MA, USA
| | - Nirupa R Matthan
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA
| | - Krishna Rao Maddipati
- Department of Pathology, Lipidomics Core Facility, Wayne State University, Detroit, MI, USA
| | - Stefania Lamon-Fava
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA.
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Bowden GD, Reis PM, Rogers MB, Bone Relat RM, Brayton KA, Wilson SK, Di Genova BM, Knoll LJ, Nepveux V FJ, Tai AK, Ramadhar TR, Clardy J, O'Connor RM. A conserved coccidian gene is involved in Toxoplasma sensitivity to the anti-apicomplexan compound, tartrolon E. Int J Parasitol Drugs Drug Resist 2020; 14:1-7. [PMID: 32738587 PMCID: PMC7394737 DOI: 10.1016/j.ijpddr.2020.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/20/2020] [Accepted: 07/23/2020] [Indexed: 12/23/2022]
Abstract
New treatments for the diseases caused by apicomplexans are needed. Recently, we determined that tartrolon E (trtE), a secondary metabolite derived from a shipworm symbiotic bacterium, has broad-spectrum anti-apicomplexan parasite activity. TrtE inhibits apicomplexans at nM concentrations in vitro, including Cryptosporidium parvum, Toxoplasma gondii, Sarcocystis neurona, Plasmodium falciparum, Babesia spp. and Theileria equi. To investigate the mechanism of action of trtE against apicomplexan parasites, we examined changes in the transcriptome of trtE-treated T. gondii parasites. RNA-Seq data revealed that the gene, TGGT1_272370, which is broadly conserved in the coccidia, is significantly upregulated within 4 h of treatment. Using bioinformatics and proteome data available on ToxoDB, we determined that the protein product of this tartrolon E responsive gene (trg) has multiple transmembrane domains, a phosphorylation site, and localizes to the plasma membrane. Deletion of trg in a luciferase-expressing T. gondii strain by CRISPR/Cas9 resulted in a 68% increase in parasite resistance to trtE treatment, supporting a role for the trg protein product in the response of T. gondii to trtE treatment. Trg is conserved in the coccidia, but not in more distantly related apicomplexans, indicating that this response to trtE may be unique to the coccidians, and other mechanisms may be operating in other trtE-sensitive apicomplexans. Uncovering the mechanisms by which trtE inhibits apicomplexans may identify shared pathways critical to apicomplexan parasite survival and advance the search for new treatments.
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Affiliation(s)
- Gregory D Bowden
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, P.O. Box 647040, Pullman, WA, 99164-7040, USA
| | - Patricia M Reis
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, P.O. Box 647040, Pullman, WA, 99164-7040, USA
| | - Maxwell B Rogers
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, P.O. Box 647040, Pullman, WA, 99164-7040, USA
| | - Rachel M Bone Relat
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, P.O. Box 647040, Pullman, WA, 99164-7040, USA
| | - Kelly A Brayton
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, P.O. Box 647040, Pullman, WA, 99164-7040, USA
| | - Sarah K Wilson
- Department of Medical Microbiology and Immunology, University of Wisconsin - Madison, 1550 Linden Dr Madison, WI, 53706, USA
| | - Bruno Martorelli Di Genova
- Department of Medical Microbiology and Immunology, University of Wisconsin - Madison, 1550 Linden Dr Madison, WI, 53706, USA
| | - Laura J Knoll
- Department of Medical Microbiology and Immunology, University of Wisconsin - Madison, 1550 Linden Dr Madison, WI, 53706, USA
| | - Felix J Nepveux V
- Division of Geographic Medicine and Infectious Disease, Tufts Medical Center, 60 Tremont St 3rd Fl, Boston, MA, 02116, USA
| | - Albert K Tai
- Department of Immunology, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA, 02111, USA
| | - Timothy R Ramadhar
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue C-213, Boston, MA, 02115, USA
| | - Jon Clardy
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue C-213, Boston, MA, 02115, USA
| | - Roberta M O'Connor
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, P.O. Box 647040, Pullman, WA, 99164-7040, USA.
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8
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Balasubramanian S, Osburne MS, BrinJones H, Tai AK, Leong JM. Prophage induction, but not production of phage particles, is required for lethal disease in a microbiome-replete murine model of enterohemorrhagic E. coli infection. PLoS Pathog 2019; 15:e1007494. [PMID: 30629725 PMCID: PMC6328086 DOI: 10.1371/journal.ppat.1007494] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [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: 06/19/2018] [Accepted: 12/01/2018] [Indexed: 12/12/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) colonize intestinal epithelium by generating characteristic attaching and effacing (AE) lesions. They are lysogenized by prophage that encode Shiga toxin 2 (Stx2), which is responsible for severe clinical manifestations. As a lysogen, prophage genes leading to lytic growth and stx2 expression are repressed, whereas induction of the bacterial SOS response in response to DNA damage leads to lytic phage growth and Stx2 production both in vitro and in germ-free or streptomycin-treated mice. Some commensal bacteria diminish prophage induction and concomitant Stx2 production in vitro, whereas it has been proposed that phage-susceptible commensals may amplify Stx2 production by facilitating successive cycles of infection in vivo. We tested the role of phage induction in both Stx production and lethal disease in microbiome-replete mice, using our mouse model encompassing the murine pathogen Citrobacter rodentium lysogenized with the Stx2-encoding phage Φstx2dact. This strain generates EHEC-like AE lesions on the murine intestine and causes lethal Stx-mediated disease. We found that lethal mouse infection did not require that Φstx2dact infect or lysogenize commensal bacteria. In addition, we detected circularized phage genomes, potentially in the early stage of replication, in feces of infected mice, confirming that prophage induction occurs during infection of microbiota-replete mice. Further, C. rodentium (Φstx2dact) mutants that do not respond to DNA damage or express stx produced neither high levels of Stx2 in vitro or lethal infection in vivo, confirming that SOS induction and concomitant expression of phage-encoded stx genes are required for disease. In contrast, C. rodentium (Φstx2dact) mutants incapable of prophage genome excision or of packaging phage genomes retained the ability to produce Stx in vitro, as well as to cause lethal disease in mice. Thus, in a microbiome-replete EHEC infection model, lytic induction of Stx-encoding prophage is essential for lethal disease, but actual phage production is not.
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Affiliation(s)
- Sowmya Balasubramanian
- Department of Molecular Biology and Microbiology at Tufts University School of Medicine, Boston, MA, United States of America
| | - Marcia S. Osburne
- Department of Molecular Biology and Microbiology at Tufts University School of Medicine, Boston, MA, United States of America
| | - Haley BrinJones
- Department of Molecular Biology and Microbiology at Tufts University School of Medicine, Boston, MA, United States of America
| | - Albert K. Tai
- Department of Immunology at Tufts University School of Medicine, Boston, MA, United States of America
| | - John M. Leong
- Department of Molecular Biology and Microbiology at Tufts University School of Medicine, Boston, MA, United States of America
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9
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Pfalzer AC, Leung K, Crott JW, Kim SJ, Tai AK, Parnell LD, Kamanu FK, Liu Z, Rogers G, Shea MK, Garcia PE, Mason JB. Incremental Elevations in TNFα and IL6 in the Human Colon and Procancerous Changes in the Mucosal Transcriptome Accompany Adiposity. Cancer Epidemiol Biomarkers Prev 2018; 27:1416-1423. [PMID: 30291114 DOI: 10.1158/1055-9965.epi-18-0121] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 05/31/2018] [Accepted: 08/16/2018] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Obesity, a risk factor for colorectal cancer, raises systemic levels of proinflammatory mediators. Whether increased levels also reside in the colons of obese individuals and are accompanied by procancerous alterations in the mucosal transcriptome is unknown. METHODS Concentrations of TNFα, IL1β, and IL6 in blood and colonic mucosa of 16 lean and 26 obese individuals were examined. Differences in the mucosal transcriptome between the two groups were defined. RESULTS Plasma IL6 and TNFα were 1.4- to 3-fold elevated in obese subjects [body mass index (BMI) ≥ 34 kg/m2] compared with the lean controls (P < 0.01). Among individuals with BMI ≥ 34 kg/m2 colonic concentrations of IL6 and TNFα were 2- to 3-fold greater than in lean subjects (P < 0.03). In a general linear model, adjusted for NSAID use, colonic IL6 (partial r = 0.41; P < 0.01) and TNFα (partial r = 0.41; P = 0.01) increased incrementally over the entire range of BMIs (18.1-45.7). Regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) was associated with a reduction in colonic IL6 (β = -0.65, P < 0.02). RNA sequencing (NSAID users excluded) identified 182 genes expressed differentially between lean and obese subjects. The two gene networks most strongly linked to changes in expression included several differentially expressed genes known to regulate the procarcinogenic signaling pathways, NFκB and ERK 1/2, in a pattern consistent with upregulation of each in the obese subjects. CONCLUSIONS Incremental increases in two major proinflammatory colonic cytokines are associated with increasing BMI, and in the obese state are accompanied by procancerous changes in the transcriptome. IMPACT These observations delineate means by which an inflammatory milieu may contribute to obesity-promoted colon cancer.
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Affiliation(s)
- Anna C Pfalzer
- Vitamins & Carcinogenesis Laboratory, The Jean Mayer U.S.D.A. Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts.,Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts
| | - Keith Leung
- Vitamins & Carcinogenesis Laboratory, The Jean Mayer U.S.D.A. Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
| | - Jimmy W Crott
- Vitamins & Carcinogenesis Laboratory, The Jean Mayer U.S.D.A. Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
| | - Susan J Kim
- Vitamins & Carcinogenesis Laboratory, The Jean Mayer U.S.D.A. Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
| | - Albert K Tai
- Genomics Core, Tufts University School of Medicine, Boston, Massachusetts
| | - Laurence D Parnell
- Agricultural Research Service, The Jean Mayer U.S.D.A. Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
| | - Frederick K Kamanu
- Nutrition and Genomics Laboratory, The Jean Mayer U.S.D.A. Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
| | - Zhenhua Liu
- School of Public Health and Health Sciences, University of Massachusetts, Amherst, Massachusetts
| | - Gail Rogers
- Nutritional Epidemiology Laboratory, The Jean Mayer U.S.D.A. Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
| | - M Kyla Shea
- Vitamin K Laboratory, The Jean Mayer U.S.D.A. Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
| | - Paloma E Garcia
- Vitamins & Carcinogenesis Laboratory, The Jean Mayer U.S.D.A. Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
| | - Joel B Mason
- Vitamins & Carcinogenesis Laboratory, The Jean Mayer U.S.D.A. Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts. .,Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts.,Division of Gastroenterology, Tufts Medical Center, Boston, Massachusetts.,Division of Clinical Nutrition, Tufts Medical Center, Boston, Massachusetts
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10
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Geisinger E, Mortman NJ, Vargas-Cuebas G, Tai AK, Isberg RR. A global regulatory system links virulence and antibiotic resistance to envelope homeostasis in Acinetobacter baumannii. PLoS Pathog 2018; 14:e1007030. [PMID: 29795704 PMCID: PMC5967708 DOI: 10.1371/journal.ppat.1007030] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [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: 11/27/2017] [Accepted: 04/16/2018] [Indexed: 11/19/2022] Open
Abstract
The nosocomial pathogen Acinetobacter baumannii is a significant threat due to its ability to cause infections refractory to a broad range of antibiotic treatments. We show here that a highly conserved sensory-transduction system, BfmRS, mediates the coordinate development of both enhanced virulence and resistance in this microorganism. Hyperactive alleles of BfmRS conferred increased protection from serum complement killing and allowed lethal systemic disease in mice. BfmRS also augmented resistance and tolerance against an expansive set of antibiotics, including dramatic protection from β-lactam toxicity. Through transcriptome profiling, we showed that BfmRS governs these phenotypes through global transcriptional regulation of a post-exponential-phase-like program of gene expression, a key feature of which is modulation of envelope biogenesis and defense pathways. BfmRS activity defended against cell-wall lesions through both β-lactamase-dependent and -independent mechanisms, with the latter being connected to control of lytic transglycosylase production and proper coordination of morphogenesis and division. In addition, hypersensitivity of bfmRS knockouts could be suppressed by unlinked mutations restoring a short, rod cell morphology, indicating that regulation of drug resistance, pathogenicity, and envelope morphogenesis are intimately linked by this central regulatory system in A. baumannii. This work demonstrates that BfmRS controls a global regulatory network coupling cellular physiology to the ability to cause invasive, drug-resistant infections. Infections with the hospital-acquired bacterium Acinetobacter baumannii are highly difficult to treat. The pathogen has evolved multiple lines of defense against antimicrobial stress, including a barrier-forming cell envelope as well as control systems that respond to antimicrobial stresses by enhancing antibiotic resistance and virulence. Here, we uncovered the role of a key stress-response system, BfmRS, in controlling the transition of A. baumannii to a state of heightened resistance and virulence. We show that BfmRS enhances pathogenicity in mammalian hosts, and augments the ability to grow in the presence of diverse antibiotics and tolerate transient, high-level antibiotic exposures. Connected to these effects is the ability of BfmRS to globally reprogram gene expression and control multiple pathways that build, protect, and shape the cell envelope. Moreover, we determined that resistance-enhancing mutations bypassing the need for BfmRS also modulate envelope- and morphology-associated pathways, further linking control of physiology with resistance in A. baumannii. This work uncovers a global control circuit that shifts cellular physiology in ways that promote hospital-associated disease, and points to inhibition of this circuit as a potential strategy for disarming the pathogen.
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Affiliation(s)
- Edward Geisinger
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
| | - Nadav J. Mortman
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Germán Vargas-Cuebas
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Albert K. Tai
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Ralph R. Isberg
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
- * E-mail:
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11
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Yang VK, Tai AK, Huh TP, Meola DM, Juhr CM, Robinson NA, Hoffman AM. Dysregulation of valvular interstitial cell let-7c, miR-17, miR-20a, and miR-30d in naturally occurring canine myxomatous mitral valve disease. PLoS One 2018; 13:e0188617. [PMID: 29315310 PMCID: PMC5760013 DOI: 10.1371/journal.pone.0188617] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [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: 07/24/2017] [Accepted: 11/10/2017] [Indexed: 12/21/2022] Open
Abstract
Canine myxomatous mitral valve disease (MMVD) resembles the early stages of myxomatous pathology seen in human non-syndromic mitral valve prolapse, a common valvular heart disease in the adult human population. Canine MMVD is seen in older subjects, suggesting age-related epigenetic dysregulation leading to derangements in valvular cell populations and matrix synthesis or degradation. We hypothesized that valvular interstitial cells (VICs) undergo disease-relevant changes in miRNA expression. In primary VIC lines from diseased and control valves, miRNA expression was profiled using RT-qPCR and next generation sequencing. VICs from diseased valves showed phenotypic changes consistent with myofibroblastic differentiation (vimentinlow+, α-SMAhigh+), increases in senescence markers (p21, SA-β-gαl), and decreased cell viability and proliferation potential. RT-qPCR and miRNA sequencing analyses both showed significant (p<0.05) downregulation of let-7c, miR-17, miR-20a, and miR-30d in VICs from diseased valves compared to controls. Decreased let-7c, miR-17, and miR-20a may contribute to myofibroblastic differentiation in addition to cell senescence, and decreased miR-30d may disinhibit cell apoptosis. These data support the hypothesis that epigenetic dysregulation plays an important role in age-related canine MMVD.
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Affiliation(s)
- Vicky K. Yang
- Department of Clinical Sciences, Tufts University Cummings School of Veterinary Medicine, North Grafton, Massachusetts, United States of America
- * E-mail:
| | - Albert K. Tai
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Terry P. Huh
- Department of Clinical Sciences, Tufts University Cummings School of Veterinary Medicine, North Grafton, Massachusetts, United States of America
| | - Dawn M. Meola
- Department of Clinical Sciences, Tufts University Cummings School of Veterinary Medicine, North Grafton, Massachusetts, United States of America
| | - Christine M. Juhr
- Department of Clinical Sciences, Tufts University Cummings School of Veterinary Medicine, North Grafton, Massachusetts, United States of America
| | - Nicholas A. Robinson
- Department of Biomedical Sciences, Tufts University Cummings School of Veterinary Medicine, North Grafton, Massachusetts, United States of America
| | - Andrew M. Hoffman
- Department of Clinical Sciences, Tufts University Cummings School of Veterinary Medicine, North Grafton, Massachusetts, United States of America
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12
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Abdi K, Chen T, Klein BA, Tai AK, Coursen J, Liu X, Skinner J, Periasamy S, Choi Y, Kessler BM, Palmer RJ, Gittis A, Matzinger P, Duncan MJ, Singh NJ. Mechanisms by which Porphyromonas gingivalis evades innate immunity. PLoS One 2017; 12:e0182164. [PMID: 28771533 PMCID: PMC5542538 DOI: 10.1371/journal.pone.0182164] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [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: 11/02/2016] [Accepted: 07/13/2017] [Indexed: 01/08/2023] Open
Abstract
The oral cavity is home to unique resident microbial communities whose interactions with host immunity are less frequently studied than those of the intestinal microbiome. We examined the stimulatory capacity and the interactions of two oral bacteria, Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum), on Dendritic Cell (DC) activation, comparing them to the effects of the well-studied intestinal microbe Escherichia coli (E. coli). Unlike F. nucleatum and E. coli, P. gingivalis failed to activate DCs, and in fact silenced DC responses induced by F. nucleatum or E. coli. We identified a variant strain of P. gingivalis (W50) that lacked this immunomodulatory activity. Using biochemical approaches and whole genome sequencing to compare the two substrains, we found a point mutation in the hagA gene. This protein is though to be involved in the alteration of the PorSS/gingipain pathway, which regulates protein secretion into the extracellular environment. A proteomic comparison of the secreted products of the two substrains revealed enzymatic differences corresponding to this phenotype. We found that P. gingivalis secretes gingipain(s) that inactivate several key proinflammatory mediators made by DCs and/or T cells, but spare Interleukin-1 (IL-1) and GM-CSF, which can cause capillary leaks that serve as a source of the heme that P. gingivalis requires for its survival, and GM-CSF, which can cause epithelial-cell growth. Taken together, our results suggest that P. gingivalis has evolved potent mechanisms to modulate its virulence factors and dampen the innate immune response by selectively inactivating most proinflammatory cytokines.
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Affiliation(s)
- Kaveh Abdi
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland, United States of America
- * E-mail:
| | - Tsute Chen
- Department of Microbiology, The Forsyth Institute, Cambridge, Massachusetts, United States of America
| | - Brian A. Klein
- Department of Microbiology, The Forsyth Institute, Cambridge, Massachusetts, United States of America
| | - Albert K. Tai
- TUCF Genomics, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Jill Coursen
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland, United States of America
| | - Xiangdong Liu
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, United States of America
| | - Jeff Skinner
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland, United States of America
| | - Saravanan Periasamy
- National Institute of Dental and Craniofacial Research, NIH, Bethesda, Maryland, United States of America
| | - Youngnim Choi
- Department of Oromaxillofacial Infection & Immunity, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Korea
| | - Benedikt M. Kessler
- Target Discovery Institute, Nuffield Department of Clinical Medicine Oxford University, Oxford, United Kingdom
| | - Robert J. Palmer
- National Institute of Dental and Craniofacial Research, NIH, Bethesda, Maryland, United States of America
| | - Apostolos Gittis
- Research Technologies Branch, National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland, United States of America
| | - Polly Matzinger
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland, United States of America
| | - Margaret J. Duncan
- Department of Microbiology, The Forsyth Institute, Cambridge, Massachusetts, United States of America
| | - Nevil J. Singh
- University of Maryland School of Medicine, Department of Microbiology & Immunology, Baltimore, Maryland United States of America
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13
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Boyraz B, Moon DH, Segal M, Muosieyiri MZ, Aykanat A, Tai AK, Cahan P, Agarwal S. Posttranscriptional manipulation of TERC reverses molecular hallmarks of telomere disease. J Clin Invest 2016; 126:3377-82. [PMID: 27482890 DOI: 10.1172/jci87547] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 06/02/2016] [Indexed: 12/11/2022] Open
Abstract
The telomerase RNA component (TERC) is a critical determinant of cellular self-renewal. Poly(A)-specific ribonuclease (PARN) is required for posttranscriptional maturation of TERC. PARN mutations lead to incomplete 3' end processing and increased destruction of nascent TERC RNA transcripts, resulting in telomerase deficiency and telomere diseases. Here, we determined that overexpression of TERC increased telomere length in PARN-deficient cells and hypothesized that decreasing posttranscriptional 3' oligo-adenylation of TERC would counteract the deleterious effects of PARN mutations. Inhibition of the noncanonical poly(A) polymerase PAP-associated domain-containing 5 (PAPD5) increased TERC levels in PARN-mutant patient cells. PAPD5 inhibition was also associated with increases in TERC stability, telomerase activity, and telomere elongation. Our results demonstrate that manipulating posttranscriptional regulatory pathways may be a potential strategy to reverse the molecular hallmarks of telomere disease.
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14
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Pfalzer AC, Kamanu FK, Parnell LD, Tai AK, Liu Z, Mason JB, Crott JW. Interactions between the colonic transcriptome, metabolome, and microbiome in mouse models of obesity-induced intestinal cancer. Physiol Genomics 2016; 48:545-53. [DOI: 10.1152/physiolgenomics.00034.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 06/15/2016] [Indexed: 12/31/2022] Open
Abstract
Obesity is a significant risk factor for colorectal cancer (CRC); however, the relative contribution of high-fat (HF) consumption and excess adiposity remains unclear. It is becoming apparent that obesity perturbs both the intestinal microbiome and metabolome, and each has the potential to induce protumorigenic changes in the epithelial transcriptome. The physiological consequences and the degree to which these different biologic systems interact remain poorly defined. To understand the mechanisms by which obesity drives colonic tumorigenesis, we profiled the colonic epithelial transcriptome of HF-fed and genetically obese (DbDb) mice with a genetic predisposition to intestinal tumorigenesis (Apc1638N); 266 and 584 genes were differentially expressed in the colonic mucosa of HF and DbDb mice, respectively. These genes mapped to pathways involved in immune function, and cellular proliferation and cancer. Furthermore, Akt was central within the networks of interacting genes identified in both gene sets. Regression analyses of coexpressed genes with the abundance of bacterial taxa identified three taxa, previously correlated with tumor burden, to be significantly correlated with a gene module enriched for Akt-related genes. Similarly, regression of coexpressed genes with metabolites found that adenosine, which was negatively associated with inflammatory markers and tumor burden, was also correlated with a gene module enriched with Akt regulators. Our findings provide evidence that HF consumption and excess adiposity result in changes in the colonic transcriptome that, although distinct, both appear to converge on Akt signaling. Such changes could be mediated by alterations in the colonic microbiome and metabolome.
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Affiliation(s)
- Anna C. Pfalzer
- Cancer Cluster, USDA Jean Mayer Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
- Vitamins and Carcinogenesis Laboratory, USDA Jean Mayer Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
- Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts
| | - Frederick K. Kamanu
- Nutrition and Genomics Laboratory, USDA Jean Mayer Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
| | - Laurence D. Parnell
- Cancer Cluster, USDA Jean Mayer Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
- Agricultural Research Service, USDA, Jean Mayer Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
| | - Albert K. Tai
- Genomics Core, Tufts University School of Medicine, Boston, Massachusetts; and
| | - Zhenhua Liu
- Cancer Cluster, USDA Jean Mayer Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
- School of Public Health and Health Sciences, University of Massachusetts, Amherst, Massachusetts
| | - Joel B. Mason
- Cancer Cluster, USDA Jean Mayer Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
- Vitamins and Carcinogenesis Laboratory, USDA Jean Mayer Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
- Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts
| | - Jimmy W. Crott
- Cancer Cluster, USDA Jean Mayer Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
- Vitamins and Carcinogenesis Laboratory, USDA Jean Mayer Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
- Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts
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15
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Araos R, Tai AK, Snyder GM, Blaser MJ, D'Agata EMC. Predominance of Lactobacillus spp. Among Patients Who Do Not Acquire Multidrug-Resistant Organisms. Clin Infect Dis 2016; 63:937-943. [PMID: 27358350 DOI: 10.1093/cid/ciw426] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 06/17/2016] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The emergence and dissemination of multidrug-resistant organisms (MDROs) is a global threat. Characterizing the human microbiome among hospitalized patients and identifying unique microbial signatures among those patients who acquire MDROs may identify novel infection prevention strategies. METHODS Adult patients admitted to 5 general medical-surgical floors at a 649-bed, tertiary care center in Boston, Massachusetts, were classified according to in-hospital antimicrobial exposure and MDRO colonization status. Within 48 hours of hospital admission (baseline) and at discharge (follow-up), rectal swab samples were obtained, and compared with samples from an external control group of healthy persons from the community. DNA was extracted from samples, next-generation sequencing performed, and microbial community structure and taxonomic features assessed, comparing those who acquired MDROs and those who had not, and the external controls. RESULTS Hospitalized patients (n = 44) had reduced microbial diversity and a greater abundance of Escherichia spp. and Enterococcus spp. than healthy controls (n = 26). Among hospitalized patients, 25 had no MDROs at the time of the baseline sample and were also exposed to antimicrobials. Among this group, 7 (28%) acquired ≥1 MDRO; demographic and clinical characteristics were similar between MDRO-acquisition and MDRO-nonacquisition groups. Patients in the nonacquisition group had consistently higher Lactobacillus spp. abundance than those in the acquisition group (linear discriminant score, 3.97; P = .04). CONCLUSIONS The fecal microbiota of the hospitalized subjects had abnormal community composition, and Lactobacillus spp. was associated with lack of MDRO acquisition, consistent with a protective role.
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Affiliation(s)
- Rafael Araos
- Department of Medicine, Facultad de Medicina Clinica Alemana, Universidad del Desarrollo, Santiago, Chile
| | - Albert K Tai
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine
| | - Graham M Snyder
- Department of Medicine, Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, Massachusetts
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Sabet JA, Park LK, Iyer LK, Tai AK, Koh GY, Pfalzer AC, Parnell LD, Mason JB, Liu Z, Byun AJ, Crott JW. Correction: Paternal B Vitamin Intake Is a Determinant of Growth, Hepatic Lipid Metabolism and Intestinal Tumor Volume in Female Apc1638N Mouse Offspring. PLoS One 2016; 11:e0154979. [PMID: 27124183 PMCID: PMC4849756 DOI: 10.1371/journal.pone.0154979] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
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17
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Sabet JA, Park LK, Iyer LK, Tai AK, Koh GY, Pfalzer AC, Parnell LD, Mason JB, Liu Z, Byun AJ, Crott JW. Paternal B Vitamin Intake Is a Determinant of Growth, Hepatic Lipid Metabolism and Intestinal Tumor Volume in Female Apc1638N Mouse Offspring. PLoS One 2016; 11:e0151579. [PMID: 26968002 PMCID: PMC4788446 DOI: 10.1371/journal.pone.0151579] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [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: 07/14/2015] [Accepted: 03/01/2016] [Indexed: 11/26/2022] Open
Abstract
Background The importance of maternal nutrition to offspring health and risk of disease is well established. Emerging evidence suggests paternal diet may affect offspring health as well. Objective In the current study we sought to determine whether modulating pre-conception paternal B vitamin intake alters intestinal tumor formation in offspring. Additionally, we sought to identify potential mechanisms for the observed weight differential among offspring by profiling hepatic gene expression and lipid content. Methods Male Apc1638N mice (prone to intestinal tumor formation) were fed diets containing replete (control, CTRL), mildly deficient (DEF), or supplemental (SUPP) quantities of vitamins B2, B6, B12, and folate for 8 weeks before mating with control-fed wild type females. Wild type offspring were euthanized at weaning and hepatic gene expression profiled. Apc1638N offspring were fed a replete diet and euthanized at 28 weeks of age to assess tumor burden. Results No differences in intestinal tumor incidence or burden were found between male Apc1638N offspring of different paternal diet groups. Although in female Apc1638N offspring there were no differences in tumor incidence or multiplicity, a stepwise increase in tumor volume with increasing paternal B vitamin intake was observed. Interestingly, female offspring of SUPP and DEF fathers had a significantly lower body weight than those of CTRL fed fathers. Moreover, hepatic trigylcerides and cholesterol were elevated 3-fold in adult female offspring of SUPP fathers. Weanling offspring of the same fathers displayed altered expression of several key lipid-metabolism genes. Hundreds of differentially methylated regions were identified in the paternal sperm in response to DEF and SUPP diets. Aside from a few genes including Igf2, there was a striking lack of overlap between these genes differentially methylated in sperm and differentially expressed in offspring. Conclusions In this animal model, modulation of paternal B vitamin intake prior to mating alters offspring weight gain, lipid metabolism and tumor growth in a sex-specific fashion. These results highlight the need to better define how paternal nutrition affects the health of offspring.
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Affiliation(s)
- Julia A. Sabet
- Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Friedman School of Nutrition Science and Policy at Tufts University, Boston, Massachusetts, United States of America
| | - Lara K. Park
- Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Friedman School of Nutrition Science and Policy at Tufts University, Boston, Massachusetts, United States of America
| | - Lakshmanan K. Iyer
- Tufts Center for Neuroscience Research, Neuroscience Department, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, United States of America
| | - Albert K. Tai
- Tufts University Core Facility, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Gar Yee Koh
- Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
| | - Anna C. Pfalzer
- Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Friedman School of Nutrition Science and Policy at Tufts University, Boston, Massachusetts, United States of America
| | - Laurence D. Parnell
- Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
| | - Joel B. Mason
- Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Friedman School of Nutrition Science and Policy at Tufts University, Boston, Massachusetts, United States of America
| | - Zhenhua Liu
- Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- School of Public Health and Health Sciences, UMass Amherst, Amherst, Massachusetts, United States of America
| | - Alexander J. Byun
- Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
| | - Jimmy W. Crott
- Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Friedman School of Nutrition Science and Policy at Tufts University, Boston, Massachusetts, United States of America
- * E-mail:
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18
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Bralic RA, Tai AK, Snyder GM, Blaser M, D'agata E. Low Lactobacillus spp. Abundance Characterizes the Fecal Microbiome of Patients Acquiring Multidrug-Resistant Organisms During Hospitalization. Open Forum Infect Dis 2015. [DOI: 10.1093/ofid/ofv133.473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Moon DH, Segal M, Boyraz B, Guinan E, Hofmann I, Cahan P, Tai AK, Agarwal S. Poly(A)-specific ribonuclease (PARN) mediates 3'-end maturation of the telomerase RNA component. Nat Genet 2015; 47:1482-8. [PMID: 26482878 DOI: 10.1038/ng.3423] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 09/25/2015] [Indexed: 12/18/2022]
Abstract
Mutations in the PARN gene (encoding poly(A)-specific ribonuclease) cause telomere diseases including familial idiopathic pulmonary fibrosis (IPF) and dyskeratosis congenita, but how PARN deficiency impairs telomere maintenance is unclear. Here, using somatic cells and induced pluripotent stem cells (iPSCs) from patients with dyskeratosis congenita with PARN mutations, we show that PARN is required for the 3'-end maturation of the telomerase RNA component (TERC). Patient-derived cells as well as immortalized cells in which PARN is disrupted show decreased levels of TERC. Deep sequencing of TERC RNA 3' termini shows that PARN is required for removal of post-transcriptionally acquired oligo(A) tails that target nuclear RNAs for degradation. Diminished TERC levels and the increased proportion of oligo(A) forms of TERC are normalized by restoring PARN, which is limiting for TERC maturation in cells. Our results demonstrate a new role for PARN in the biogenesis of TERC and provide a mechanism linking PARN mutations to telomere diseases.
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Affiliation(s)
- Diane H Moon
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Boston, Massachusetts, USA.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Matthew Segal
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Boston, Massachusetts, USA.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Baris Boyraz
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Boston, Massachusetts, USA.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA.,Department of Basic Oncology, Hacettepe University Cancer Institute, Ankara, Turkey
| | - Eva Guinan
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Inga Hofmann
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Boston, Massachusetts, USA.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Patrick Cahan
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Albert K Tai
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Suneet Agarwal
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Boston, Massachusetts, USA.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
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20
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Pfalzer AC, Nesbeth PDC, Parnell LD, Iyer LK, Liu Z, Kane AV, Chen CYO, Tai AK, Bowman TA, Obin MS, Mason JB, Greenberg AS, Choi SW, Selhub J, Paul L, Crott JW. Diet- and Genetically-Induced Obesity Differentially Affect the Fecal Microbiome and Metabolome in Apc1638N Mice. PLoS One 2015; 10:e0135758. [PMID: 26284788 PMCID: PMC4540493 DOI: 10.1371/journal.pone.0135758] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [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: 05/26/2015] [Accepted: 07/24/2015] [Indexed: 01/05/2023] Open
Abstract
Obesity is a risk factor for colorectal cancer (CRC), and alterations in the colonic microbiome and metabolome may be mechanistically involved in this relationship. The relative contribution of diet and obesity per se are unclear. We compared the effect of diet- and genetically-induced obesity on the intestinal microbiome and metabolome in a mouse model of CRC. Apc1638N mice were made obese by either high fat (HF) feeding or the presence of the Leprdb/db (DbDb) mutation. Intestinal tumors were quantified and stool microbiome and metabolome were profiled. Genetic obesity, and to a lesser extent HF feeding, promoted intestinal tumorigenesis. Each induced distinct microbial patterns: taxa enriched in HF were mostly Firmicutes (6 of 8) while those enriched in DbDb were split between Firmicutes (7 of 12) and Proteobacteria (5 of 12). Parabecteroides distasonis was lower in tumor-bearing mice and its abundance was inversely associated with colonic Il1b production (p<0.05). HF and genetic obesity altered the abundance of 49 and 40 fecal metabolites respectively, with 5 in common. Of these 5, adenosine was also lower in obese and in tumor-bearing mice (p<0.05) and its concentration was inversely associated with colonic Il1b and Tnf production (p<0.05). HF and genetic obesity differentially alter the intestinal microbiome and metabolome. A depletion of adenosine and P.distasonis in tumor-bearing mice could play a mechanistic role in tumor formation. Adenosine and P. distasonis have previously been shown to be anti-inflammatory in the colon and we postulate their reduction could promote tumorigenesis by de-repressing inflammation.
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Affiliation(s)
- Anna C. Pfalzer
- Cancer Cluster, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts, United States of America
| | - Paula-Dene C. Nesbeth
- Cancer Cluster, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts, United States of America
| | - Laurence D. Parnell
- Cancer Cluster, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Agricultural Research Service, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
| | - Lakshmanan K. Iyer
- Neuroscience Department, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Zhenhua Liu
- Cancer Cluster, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts, United States of America
- Department of Nutrition, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Anne V. Kane
- Cancer Cluster, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Phoenix Laboratory, Tufts Medical Center, Boston, Massachusetts, United States of America
| | - C-Y. Oliver Chen
- Cancer Cluster, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts, United States of America
| | - Albert K. Tai
- Genomics Core, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Thomas A. Bowman
- Cancer Cluster, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
| | - Martin S. Obin
- Cancer Cluster, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts, United States of America
| | - Joel B. Mason
- Cancer Cluster, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts, United States of America
| | - Andrew S. Greenberg
- Cancer Cluster, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts, United States of America
| | - Sang-Woon Choi
- Cancer Cluster, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- CHA University School of Medicine, Seoul, South Korea
| | - Jacob Selhub
- Cancer Cluster, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts, United States of America
| | - Ligi Paul
- Cancer Cluster, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts, United States of America
| | - Jimmy W. Crott
- Cancer Cluster, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, United States of America
- Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts, United States of America
- * E-mail:
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Dinh DM, Volpe GE, Duffalo C, Bhalchandra S, Tai AK, Kane AV, Wanke CA, Ward HD. Intestinal microbiota, microbial translocation, and systemic inflammation in chronic HIV infection. J Infect Dis 2014; 211:19-27. [PMID: 25057045 DOI: 10.1093/infdis/jiu409] [Citation(s) in RCA: 319] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Despite effective antiretroviral therapy (ART), patients with chronic human immunodeficiency virus (HIV) infection have increased microbial translocation and systemic inflammation. Alterations in the intestinal microbiota may play a role in microbial translocation and inflammation. METHODS We profiled the fecal microbiota by pyrosequencing the gene encoding 16S ribosomal RNA (rRNA) and measured markers of microbial translocation and systemic inflammation in 21 patients who had chronic HIV infection and were receiving suppressive ART (cases) and 16 HIV-uninfected controls. RESULTS The fecal microbial community composition was significantly different between cases and controls. The relative abundance of Proteobacteria, Gammaproteobacteria, Enterobacteriales, Enterobacteriaceae, Erysipelotrichi, Erysipelotrichales, Erysipelotrichaceae, and Barnesiella was significantly enriched in cases, whereas that of Rikenellaceae and Alistipes was depleted. The plasma soluble CD14 level (sCD14) was significantly higher and the endotoxin core immunoglobulin M (IgM) level lower in cases, compared with controls. There were significant positive correlations between the relative abundances of Enterobacteriales and Enterobacteriaceae and the sCD14 level; the relative abundances of Gammaproteobacteria, Enterobacteriales, and Enterobacteriaceae and the interleukin 1β (IL-1β) level; the relative abundances of Enterobacteriales and Enterobacteriaceae and the interferon γ level; and the relative abundances of Erysipelotrichi and Barnesiella and the TNF-α level. There were negative correlations between endotoxin core IgM and IL-1β levels. CONCLUSIONS Patients who have chronic HIV infection and are receiving suppressive ART display intestinal dysbiosis associated with increased microbial translocation and significant associations between specific taxa and markers of microbial translocation and systemic inflammation. This was an exploratory study, the findings of which need to be confirmed.
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Affiliation(s)
- Duy M Dinh
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center
| | - Gretchen E Volpe
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center Department of Public Health and Community Medicine
| | - Chad Duffalo
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center
| | - Seema Bhalchandra
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center
| | - Albert K Tai
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston, Massachusetts
| | - Anne V Kane
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center
| | - Christine A Wanke
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center Department of Public Health and Community Medicine
| | - Honorine D Ward
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center Department of Public Health and Community Medicine
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22
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Avalos AM, Bilate AM, Witte MD, Tai AK, He J, Frushicheva MP, Thill PD, Meyer-Wentrup F, Theile CS, Chakraborty AK, Zhuang X, Ploegh HL. Monovalent engagement of the BCR activates ovalbumin-specific transnuclear B cells. ACTA ACUST UNITED AC 2014; 211:365-79. [PMID: 24493799 PMCID: PMC3920557 DOI: 10.1084/jem.20131603] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Monovalent engagement can trigger BCR signal transduction, and fine-tuning of BCR-ligand recognition can lead to B cell nonresponsiveness, activation, or inhibition. Valency requirements for B cell activation upon antigen encounter are poorly understood. OB1 transnuclear B cells express an IgG1 B cell receptor (BCR) specific for ovalbumin (OVA), the epitope of which can be mimicked using short synthetic peptides to allow antigen-specific engagement of the BCR. By altering length and valency of epitope-bearing synthetic peptides, we examined the properties of ligands required for optimal OB1 B cell activation. Monovalent engagement of the BCR with an epitope-bearing 17-mer synthetic peptide readily activated OB1 B cells. Dimers of the minimal peptide epitope oriented in an N to N configuration were more stimulatory than their C to C counterparts. Although shorter length correlated with less activation, a monomeric 8-mer peptide epitope behaved as a weak agonist that blocked responses to cell-bound peptide antigen, a blockade which could not be reversed by CD40 ligation. The 8-mer not only delivered a suboptimal signal, which blocked subsequent responses to OVA, anti-IgG, and anti-kappa, but also competed for binding with OVA. Our results show that fine-tuning of BCR-ligand recognition can lead to B cell nonresponsiveness, activation, or inhibition.
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Affiliation(s)
- Ana M Avalos
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
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23
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Brugge D, Lane KJ, Stewart A, Tai AK, Woodin M. Highway proximity associations with blood markers of inflammation: evidence for a role for IL-1β. J Toxicol Environ Health A 2013; 76:201-5. [PMID: 23356649 PMCID: PMC4517179 DOI: 10.1080/15287394.2013.752325] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Cardiovascular disease is known to be associated with proximity to major roadways and highways. Thus, blood samples from 20 near highway and 20 urban background residents were analyzed for presence of cytokines and other biomarkers. Near-highway participants displayed significantly lower socioeconomic status (SES) and significantly higher occupational vehicle exhaust exposure and higher low-density lipoprotein (LDL) levels. Controlling for exposure to vehicle exhaust on the job, interleukin-6 (IL-6) was numerically higher in near highway participants. Using logistic regression analyses, IL-1β was significantly elevated near highway. It is interesting that elevations were found in IL-1β, a key cytokine linked to inflammation from particulate matter (PM). More studies are needed with larger sample sizes to assess the possible role of IL-1β.
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Affiliation(s)
- Doug Brugge
- Department of Public Health and Community Medicine, Tufts University School of Medicine, 136 Harrison Ave., Boston MA 02111, V: 617 636 0326
| | - Kevin J. Lane
- Department of Environmental Health, Boston University School of Public Health, 715 Albany Street, Boston MA, 02118
| | - Andrea Stewart
- College of Arts and Sciences, Tufts University, Medford, MA 02155
| | - Albert K Tai
- Department of Pathology, Tufts University School of Medicine, 150 Harrison Ave., Boston MA 02111
| | - Mark Woodin
- Department of Civil and Environmental Engineering, Tufts School of Engineering, Anderson Hall, Medford, MA 02155
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Cheng H, Byrska-Bishop M, Zhang CT, Kastrup CJ, Hwang NS, Tai AK, Lee WW, Xu X, Nahrendorf M, Langer R, Anderson DG. Stem cell membrane engineering for cell rolling using peptide conjugation and tuning of cell-selectin interaction kinetics. Biomaterials 2012; 33:5004-12. [PMID: 22494889 DOI: 10.1016/j.biomaterials.2012.03.065] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 03/18/2012] [Indexed: 12/13/2022]
Abstract
Dynamic cell-microenvironment interactions regulate many biological events and play a critical role in tissue regeneration. Cell homing to targeted tissues requires well balanced interactions between cells and adhesion molecules on blood vessel walls. However, many stem cells lack affinity with adhesion molecules. It is challenging and clinically important to engineer these stem cells to modulate their dynamic interactions with blood vessels. In this study, a new chemical strategy was developed to engineer cell-microenvironment interactions. This method allowed the conjugation of peptides onto stem cell membranes without affecting cell viability, proliferation or multipotency. Mesenchymal stem cells (MSCs) engineered in this manner showed controlled firm adhesion and rolling on E-selectin under physiological shear stresses. For the first time, these biomechanical responses were achieved by tuning the binding kinetics of the peptide-selectin interaction. Rolling of engineered MSCs on E-selectin is mediated by a Ca(2+) independent interaction, a mechanism that differs from the Ca(2+) dependent physiological process. This further illustrates the ability of this approach to manipulate cell-microenvironment interactions, in particular for the application of delivering cells to targeted tissues. It also provides a new platform to engineer cells with multiple functionalities.
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Affiliation(s)
- Hao Cheng
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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25
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Raychaudhuri S, Iartchouk O, Chin K, Tan PL, Tai AK, Ripke S, Gowrisankar S, Vemuri S, Montgomery K, Yu Y, Reynolds R, Zack DJ, Campochiaro B, Campochiaro P, Katsanis N, Daly MJ, Seddon JM. A rare penetrant mutation in CFH confers high risk of age-related macular degeneration. Nat Genet 2011; 43:1232-6. [PMID: 22019782 PMCID: PMC3225644 DOI: 10.1038/ng.976] [Citation(s) in RCA: 243] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 09/20/2011] [Indexed: 01/12/2023]
Abstract
Two common variants within CFH, the Y402H1–4 and the rs1410996 SNPs5,6, explain 17% of age-related macular degeneration (AMD) liability. However, proof for the involvement of CFH, as opposed to a neighboring transcript, and the potential mechanism of susceptibility alleles are lacking. Assuming that rare functional variants might provide mechanistic insights, we used genotype data and high throughput sequencing to discover a rare high-risk CFH haplotype containing an R1210C mutation. This allele has been implicated previously in atypical hemolytic uremic syndrome, and abrogates C-terminal ligand binding7,8. Genotyping R1210C in 2,423 AMD cases and 1,122 controls demonstrated high penetrance (present in 40 cases versus 1 control, p=7.0×10−6) and six year earlier onset of disease (p=2.3×10−6). This result suggests that loss of function alleles at CFH likely drive AMD risk. This finding represents one of the first instances where a common complex disease variant has led to discovery of a rare penetrant mutation.
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Affiliation(s)
- Soumya Raychaudhuri
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts, USA.
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Oakes B, Tai AK, Cingöz O, Henefield MH, Levine S, Coffin JM, Huber BT. Contamination of human DNA samples with mouse DNA can lead to false detection of XMRV-like sequences. Retrovirology 2010; 7:109. [PMID: 21171973 PMCID: PMC3022687 DOI: 10.1186/1742-4690-7-109] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Accepted: 12/20/2010] [Indexed: 01/13/2023] Open
Abstract
Background In 2006, a novel gammaretrovirus, XMRV (xenotropic murine leukemia virus-related virus), was discovered in some prostate tumors. A more recent study indicated that this infectious retrovirus can be detected in 67% of patients suffering from chronic fatigue syndrome (CFS), but only very few healthy controls (4%). However, several groups have published to date that they could not identify XMRV RNA or DNA sequences in other cohorts of CFS patients, while another group detected murine leukemia virus (MLV)-like sequences in 87% of such patients, but only 7% of healthy controls. Since there is a high degree of similarity between XMRV and abundant endogenous MLV proviruses, it is important to distinguish contaminating mouse sequences from true infections. Results DNA from the peripheral blood of 112 CFS patients and 36 healthy controls was tested for XMRV with two different PCR assays. A TaqMan qPCR assay specific for XMRV pol sequences was able to detect viral DNA from 2 XMRV-infected cells (~ 10-12 pg DNA) in up to 5 μg of human genomic DNA, but yielded negative results in the test of 600 ng genomic DNA from 100,000 peripheral blood cells of all samples tested. However, positive results were obtained with some of these samples, using a less specific nested PCR assay for a different XMRV sequence. DNA sequencing of the PCR products revealed a wide variety of virus-related sequences, some identical to those found in prostate cancer and CFS patients, others more closely related to known endogenous MLVs. However, all samples that tested positive for XMRV and/or MLV DNA were also positive for the highly abundant intracisternal A-type particle (IAP) long terminal repeat and most were positive for murine mitochondrial cytochrome oxidase sequences. No contamination was observed in any of the negative control samples, containing those with no DNA template, which were included in each assay. Conclusions Mouse cells contain upwards of 100 copies each of endogenous MLV DNA. Even much less than one cell's worth of DNA can yield a detectable product using highly sensitive PCR technology. It is, therefore, vital that contamination by mouse DNA be monitored with adequately sensitive assays in all samples tested.
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Affiliation(s)
- Brendan Oakes
- Department of Pathology, Tufts University School of Medicine, 150 Harrison Avenue, Boston, MA 02111, USA
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27
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Danilova OV, Tai AK, Mele DA, Beinborn M, Leiter AB, Greenberg AS, Perfield JW, Defuria J, Singru PS, Lechan RM, Huber BT. Neurogenin 3-specific dipeptidyl peptidase-2 deficiency causes impaired glucose tolerance, insulin resistance, and visceral obesity. Endocrinology 2009; 150:5240-8. [PMID: 19819973 PMCID: PMC2795711 DOI: 10.1210/en.2009-0386] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The control of glucose metabolism is a complex process, and dysregulation at any level can cause impaired glucose tolerance and insulin resistance. These two defects are well-known characteristics associated with obesity and onset of type 2 diabetes. Here we introduce the N-terminal dipeptidase, DPP2, as a novel regulator of the glucose metabolism. We generated mice with a neurogenin 3 (NGN3)-specific DPP2 knockdown (kd) to explore a possible role of DPP2 in maintaining metabolic homeostasis. These mice spontaneously developed hyperinsulinemia, glucose intolerance, and insulin resistance by 4 months of age. In addition, we observed an increase in food intake in DPP2 kd mice, which was associated with a significant increase in adipose tissue mass and enhanced liver steatosis but no difference in body weight. In accordance with these findings, the mutant mice had a higher rate of respiratory exchange than the control littermates. This phenotype was exacerbated with age and when challenged with a high-fat diet. We report, for the first time, that DPP2 enzyme activity is essential for preventing hyperinsulinemia and maintaining glucose homeostasis. Interestingly, the phenotype of NGN3-DPP2 kd mice is opposite that of DPP4 knockout mice with regard to glucose metabolism, namely the former have normal glucagon-like peptide 1 levels but present with glucose intolerance, whereas the latter have increased glucagon-like peptide 1, which is accompanied by augmented glucose tolerance.
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Affiliation(s)
- Olga V Danilova
- Department of Pathology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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Abstract
BACKGROUND The human endogenous retrovirus K-18 (HERV-K18) encodes a superantigen that causes deregulation of the immune system. This provirus is transcriptionally silent, but can be induced by Epstein-Barr virus (EBV) infection and IFN-alpha treatment. OBJECTIVES Since the herpesvirus EBV induces HERV-K18 expression in human B cells, it was of interest to determine if other herpesviruses would have similar HERV-K18 transactivation properties. Human herpesvirus (HHV)-6A, a neurotropic virus associated with multiple sclerosis, was a logical candidate for these studies. STUDY DESIGN HSB2 cells (HHV-6-negative control), HSB2-ML cells (containing latent HHV-6A genome) and HSB2/HHV-6A cells (HSB-2 cells productively infected with HHV-6A) were compared for their level of HERV-K18 transcription, using quantitative RT-PCR. RESULTS Latently infected HSB2-ML cells showed a significant increase in HERV-K18 RNA compared to the control cells. HERV-K18 expression was even greater in HSB2 cells productively infected with HHV-6A for 78h. CONCLUSION These results imply that HHV-6A, either in latent form or during acute infection, directly transactivates HERV-K18. This HERV-K18 induction may be mediated through IFN-alpha that is produced by the HHV-6A-infected cells. The functional implications of superantigen expression are discussed.
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Affiliation(s)
- Albert K Tai
- Department of Pathology, Tufts University School of Medicine, Boston, MA 02111, United States
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Hsiao FC, Tai AK, Deglon A, Sutkowski N, Longnecker R, Huber BT. EBV LMP-2A employs a novel mechanism to transactivate the HERV-K18 superantigen through its ITAM. Virology 2008; 385:261-6. [PMID: 19070345 DOI: 10.1016/j.virol.2008.11.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Revised: 11/12/2008] [Accepted: 11/17/2008] [Indexed: 01/31/2023]
Abstract
EBV encodes latent membrane protein (LMP)-2A that functions as a homologue of the activated BCR. We have previously shown that LMP-2A transactivates a human endogenous retrovirus, HERV-K18, in infected B-lymphocytes. The Env protein of HERV-K18 encodes a superantigen that strongly stimulates a large number of T cells. To delineate the mechanism through which LMP-2A transactivates HERV-K18 env, we tested a panel of tyrosine mutants of LMP-2A in a murine B lymphoma that stably harbors HERV-K18. Our analysis revealed that the immunoreceptor tyrosine-based activation motif (ITAM) of LMP-2A is important for HERV-K18 env transactivation. ITAM contains 2 tyrosines that initiate signaling cascades when both residues are phosphorylated. However, in our study, single-tyrosine mutants of ITAM still retained full induction of HERV-K18 env. After truncating 25 kb of genomic sequence downstream of HERV-K18, LMP-2A failed to transactivate HERV-K18 env. Thus, an LMP-2A-inducible element is located downstream of HERV-K18.
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Affiliation(s)
- Francis C Hsiao
- Department of Pathology, Tufts University School of Medicine, Boston, MA 02111, USA
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Tai AK, O'Reilly EJ, Alroy KA, Simon KC, Munger KL, Huber BT, Ascherio A. Human endogenous retrovirus-K18 Env as a risk factor in multiple sclerosis. Mult Scler 2008; 14:1175-80. [PMID: 18701576 DOI: 10.1177/1352458508094641] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BackgroundThe human endogenous retrovirus (HERV)-K18 Env is an Epstein-Barr virus (EBV)-associated superantigen. Given the evidence for a role of EBV in the etiology of multiple sclerosis (MS), HERV-K18 Env is a plausible candidate for association with MS.ObjectiveTo assess whether variation in HERV-K18 Env is a risk factor for MS.MethodsWe developed a single nucleotide polymorphism-based genotyping method to determine the distribution of the three alleles of HERV-K18 env. We then conducted a nested case-control study including 207 MS cases and 403 matched controls. Analyses were replicated in an independent series of 909 MS cases and 339 controls.ResultsOverall, there was a significant association between HERV-K18 env genotype and MS risk (chi2 P = 0.03). As compared with K18.2/K18.2 individuals, risk of MS was three fold higher among K18.3/K18.3 individuals (P = 0.03). An increase in MS risk among carriers of the K18.3 allele was also observed in the replication study, but did not reach statistical significance. In pooled analyses, K18.3/K18.3 individuals had a significantly increased risk of MS (relative risks [RR] comparing K18.3/K18.3 vs K18.2/K18.2 = 2.7; 95% confidence interval: 1.1-6.4).ConclusionVariation in EBV-associated superantigen HERV-K18 Env could influence the genetic susceptibility to MS.
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Affiliation(s)
- A K Tai
- Department of Pathology, Tufts University School of Medicine, Boston, Massachusetts, USA
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Chen G, Tai AK, Lin M, Chang F, Terhorst C, Huber BT. Increased proliferation of CD8+ T cells in SAP-deficient mice is associated with impaired activation-induced cell death. Eur J Immunol 2007; 37:663-74. [PMID: 17266174 DOI: 10.1002/eji.200636417] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Defective signaling lymphocyte activation molecule (SLAM)-associated protein (SAP) is responsible for the human X-linked lymphoproliferative syndrome. Defects in T helper 2, natural killer, natural killer T and B cells have been demonstrated in SAP-deficient humans and mice, and increased proliferation of CD8+ T cells has been observed. In the current study, we investigated the properties of CD8+ T cell proliferation and activation-induced cell death (AICD), using OT-I T cell receptor (TCR)-transgenic mice on either wild-type (WT) or SAP-/- background. Interestingly, we found that ovalbumin peptide-activated SAP-/- CD8+ T cells have lower AICD compared to their WT counterparts. Furthermore, the induction of p73, a key mediator of TCR-induced apoptosis through the mitochondrial apoptotic pathway, was significantly reduced at both the mRNA and protein levels in the activated mutant cells. Meanwhile, a reduced level of activated caspase 9 was observed in the mutant cells. We conclude that reduced AICD in activated SAP-/- CD8+ T cells is associated with impaired p73 induction, indicating that the initiation of the mitochondrial apoptotic pathway might be impaired. Our data demonstrate an intrinsic defect in SAP-/- CD8+ T cells and shed light on the increased responsiveness of CD8+ T cells in SAP-/- mice.
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Affiliation(s)
- Gang Chen
- Department of Pathology, Tufts University School of Medicine, Boston, MA 02111, USA
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Tai AK, Lin M, Chang F, Chen G, Hsiao F, Sutkowski N, Huber BT. Murine Vβ3+and Vβ7+T Cell Subsets Are Specific Targets for the HERV-K18 Env Superantigen. J Immunol 2006; 177:3178-84. [PMID: 16920956 DOI: 10.4049/jimmunol.177.5.3178] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Superantigens are a class of proteins that are derived from microorganisms and have the unique characteristic of stimulating T cells in a TCR Vbeta-specific manner, causing massive T cell proliferation and immune deregulation. For this reason, superantigens have been implicated in the development of multiple diseases. We have previously identified and cloned an EBV-associated superantigen, human endogenous retrovirus (HERV)-K18 envelope protein (Env). This superantigen is transactivated upon IFN-alpha treatment and EBV infection and stimulates human Vbeta13+ T cells. Due to the limited scope of work that can be conducted with human samples and the complexity of HERVs in general, we set out to study the physiological effects of HERV-K18 Env in a murine model. In this report, we demonstrate the superantigen activity of HERV-K18 Env in mice and describe the generation of HERV-K18 transgenics, using a bacterial artificial chromosome as transgenes that allow the faithful reproduction of the expression pattern of this human provirus. From our in vitro and in vivo results we conclude that HERV-K18 Env stimulates Vbeta3+ and Vbeta7+ T cells in mice. The definition of the murine Vbeta specificity and the establishment of a transgenic model will permit the investigation of the role of this superantigen in the life cycle of EBV and its implicated diseases.
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Affiliation(s)
- Albert K Tai
- Department of Pathology, Tufts University School of Medicine, Boston, MA 02111, USA
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Chen G, Tai AK, Lin M, Chang F, Terhorst C, Huber BT. Signaling Lymphocyte Activation Molecule-Associated Protein Is a Negative Regulator of the CD8 T Cell Response in Mice. J Immunol 2005; 175:2212-8. [PMID: 16081788 DOI: 10.4049/jimmunol.175.4.2212] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The primary manifestation of X-linked lymphoproliferative syndrome, caused by a dysfunctional adapter protein, signaling lymphocyte activation molecule-associated protein (SAP), is an excessive T cell response upon EBV infection. Using the SAP-/- mouse as a model system for the human disease, we compared the response of CD8+ T cells from wild-type (wt) and mutant mice to various stimuli. First, we observed that CD8+ T cells from SAP-/- mice proliferate more vigorously than those from wt mice upon CD3/CD28 cross-linking in vitro. Second, we analyzed the consequence of SAP deficiency on CTL effector function and homeostasis. For this purpose, SAP-/- and wt mice were infected with the murine gamma-herpesvirus 68 (MHV-68). At 2 wk postinfection, the level of viral-specific CTL was much higher in mutant than in wt mice, measured both ex vivo and in vivo. In addition, we established that throughout 45 days of MHV-68 infection the frequency of virus-specific CD8+ T cells producing IFN-gamma was significantly higher in SAP-/- mice. Consequently, the level of latent infection by MHV-68 was considerably lower in SAP-/- mice, which indicates that SAP-/- CTL control this infection more efficiently than wt CTL. Finally, we found that the Vbeta4-specific CD8+ T cell expansion triggered by MHV-68 infection is also enhanced and prolonged in SAP-/- mice. Taken together, our data indicate that SAP functions as a negative regulator of CD8+ T cell activation.
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MESH Headings
- Animals
- Antigens, CD
- BALB 3T3 Cells
- CD28 Antigens/immunology
- CD28 Antigens/metabolism
- CD3 Complex/immunology
- CD3 Complex/metabolism
- CD8-Positive T-Lymphocytes/cytology
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/metabolism
- CD8-Positive T-Lymphocytes/virology
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Cell Line, Tumor
- Cell Proliferation
- Cross-Linking Reagents/metabolism
- Cytotoxicity, Immunologic/genetics
- Down-Regulation/immunology
- Epitopes, T-Lymphocyte/immunology
- Gammaherpesvirinae/immunology
- Glycoproteins/metabolism
- Herpesviridae Infections/genetics
- Herpesviridae Infections/immunology
- Immunoglobulins/metabolism
- Intracellular Signaling Peptides and Proteins/deficiency
- Intracellular Signaling Peptides and Proteins/genetics
- Intracellular Signaling Peptides and Proteins/physiology
- Lymphocyte Activation/genetics
- Lymphocyte Activation/immunology
- Lymphocyte Count
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Cell Surface
- Signal Transduction/immunology
- Signaling Lymphocytic Activation Molecule Associated Protein
- Signaling Lymphocytic Activation Molecule Family Member 1
- Spleen/cytology
- Spleen/immunology
- Spleen/virology
- Virus Latency/immunology
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Affiliation(s)
- Gang Chen
- Department of Pathology, Tufts University School of Medicine, Boston, MA 02111, USA
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Chau KY, Munshi N, Keane-Myers A, Cheung-Chau KW, Tai AK, Manfioletti G, Dorey CK, Thanos D, Zack DJ, Ono SJ. The architectural transcription factor high mobility group I(Y) participates in photoreceptor-specific gene expression. J Neurosci 2000; 20:7317-24. [PMID: 11007889 PMCID: PMC6772757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
The nonhistone chromosomal proteins high mobility group I(Y) [HMG I(Y)] have been shown to function as architectural transcription factors facilitating enhanceosome formation on a variety of mammalian promoters. Specifically, they have been shown to act as a "molecular glue" mediating protein-protein and protein-DNA contacts within the enhanceosome complex. HMG I(Y) proteins are expressed at high levels in embryonic and transformed cells and have been implicated in transcriptional regulation in these cells. Terminally differentiated cells, however, have been reported to express only minimal, if any, HMG I(Y). In contrast to these observations, we show here that adult mouse retinal photoreceptors, which are terminally differentiated cells, express high levels of these proteins. Using retinoblastoma cells as an approximate model, we further demonstrate in transiently transfected cells that inhibition of HMG I(Y) expression and mutation of HMG I(Y) binding sites significantly reduce rhodopsin promoter activity. DNase I footprint analysis indicates that HMG I protein interacts with a discrete site within the rhodopsin proximal promoter. This site overlaps with the binding site for Crx, a paired-like homeodomain transcription factor that is essential for photoreceptor functioning and that when mutated causes several forms of human photoreceptor degeneration. Both biochemical and functional experiments demonstrate that HMG I(Y) physically associate with Crx and that their interaction with DNA is required for high-level transcription of the rhodopsin gene. These data provide the first demonstration that HMG I(Y) can be important for gene activation in terminally differentiated cells.
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Affiliation(s)
- K Y Chau
- The Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts 02114, USA
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Arlotta P, Tai AK, Manfioletti G, Clifford C, Jay G, Ono SJ. Transgenic mice expressing a truncated form of the high mobility group I-C protein develop adiposity and an abnormally high prevalence of lipomas. J Biol Chem 2000; 275:14394-400. [PMID: 10747931 DOI: 10.1074/jbc.m000564200] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chromosomal translocations in human lipomas frequently create fusion transcripts encoding high mobility group (HMG) I-C DNA-binding domains and C-terminal sequences from different presumed transcription factors, suggesting a potential role for HMG I-C in the development of lipomas. To evaluate the role of the HMG I-C component, the three DNA-binding domains of HMG I-C have now been expressed in transgenic mice. Despite the ubiquitous expression of the truncated HMG I-C protein, the transgenic mice develop a selective abundance of fat tissue early in life, show marked adipose tissue inflammation, and have an abnormally high incidence of lipomas. These findings demonstrate that the DNA-binding domains of HMG I-C, in the absence of a C-terminal fusion partner, are sufficient to perturb adipogenesis and predispose to lipomas. We provide data supporting the central utility of this animal model as a tool to understand the molecular mechanisms underlying the development of one of the most common kind of human benign tumors.
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Affiliation(s)
- P Arlotta
- Schepens Eye Research Institute, Division of Rheumatology, Immunology & Allergy, Department of Medicine, Brigham & Women's Hospital, and Committee on Immunology, Harvard Medical School, Boston, Massachusetts 02114, USA
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Ono SJ, Zhou G, Tai AK, Inaba M, Kinoshita K, Honjo T. Identification of a stimulus-dependent DNase I hypersensitive site between the Ialpha and Calpha exons during immunoglobulin heavy chain class switch recombination. FEBS Lett 2000; 467:268-72. [PMID: 10675552 DOI: 10.1016/s0014-5793(00)01151-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The complete humoral response to foreign antigen depends upon two distinct recombination events within the heavy chain locus of immunoglobulin. The first recombination event takes place in what will become the antigen combining site of the antibody molecule, encoded by V, D and J segments. The second recombination event involves the looping-out of large spans of DNA which separate the various clusters of heavy chain exons which define the different immunoglobulin isotypes, or classes. While a great deal has been learned about the nature of the VDJ recombinase, very little is known about the nature of the class-switch recombinase. Using a cell system where class-switch recombination occurs primarily to the IgA locus, we have looked for stimulus-dependent changes in the chromatin structure of the IgA locus which might result from interactions between components of the recombinase and cis-elements within the region. We present evidence that strongly suggests that the class-switch recombinase interacts between the Ialpha and Calpha exons of IgA, just upstream of the highly reiterated DR1 and DR2 elements. However, although multiple potential SMAD-4 sites are located precisely within the DNase I hypersensitive site and 160 bp upstream of that site, we failed to detect any evidence of DNA/protein interactions near the hypersensitive site. Moreover, recombinant SMAD-3/4 proteins fail to interact with these sites with appreciable affinity in vitro. These data suggest that some other structural alteration at this site (e.g. RNA/DNA hybrid) may mediate the nuclease sensitivity.
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Affiliation(s)
- S J Ono
- Laboratory of Molecular Immunology, The Schepens Eye Research Institute and Committee on Immunology, Harvard University, 20 Staniford St., Boston, MA, USA.
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Tai AK, Zhou G, Chau K, Ono SJ. Cis-element dependence and occupancy of the human invariant chain promoter in CIITA-dependent and -independent transcription. Mol Immunol 1999; 36:447-60. [PMID: 10449097 DOI: 10.1016/s0161-5890(99)00061-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The major histocompatibility complex (MHC)-associated invariant chain (Ii) associates with the class II alpha/beta heterodimer during its biosynthesis, inhibiting association of endogenous peptides with the peptide-binding cleft. It is therefore not surprising that there are significant similarities in regulatory mechanisms controlling the expression of the structural class II MHC and Ii genes. One important similarity is that both classes of genes can be expressed via CIITA-dependent or -independent mechanisms. In this report, we have dissected CIITA-dependent and -independent transcription of the Ii gene using an isogenic B-LCL cell pair (Jijoye and clone-13) which do or do not express the class II MHC transactivator (CIITA), respectively. Experiments using mutant or deletion constructs of the Ii gene promoter indicate that while both the X-box and li-kappaB1 elements are critical for CIITA-dependent transcription in B lymphocytes, the Ii-kappaBI element is of greater importance for CIITA-independent Ii gene transcription, with the X-box playing a secondary role. Despite these clear differences in cis-element dependence of CIITA-dependent and -independent Ii transcription, there are only subtle differences in the occupancy of these elements in vivo as assessed by genomic footprinting. These differences are restricted to occupancy of the X-box and Y-box, with which the RF-X and NF-Y complexes interact in Ii-positive cells. This difference in the occupancy of the X-box and Y-box in this cell pair indicates that while protein/protein interactions between CIITA and promoter-bound factors stabilize promoter occupancy, these interactions are not absolutely required for occupancy and transcription of the invariant chain gene.
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MESH Headings
- Antigens, Differentiation, B-Lymphocyte/genetics
- Antigens, Differentiation, B-Lymphocyte/immunology
- Base Sequence
- Cell Line
- Chloramphenicol O-Acetyltransferase/metabolism
- Enhancer Elements, Genetic
- Gene Deletion
- Genes, Reporter
- Histocompatibility Antigens Class II/genetics
- Histocompatibility Antigens Class II/immunology
- Humans
- Models, Biological
- Models, Genetic
- Models, Molecular
- Molecular Sequence Data
- NF-kappa B/genetics
- Nuclear Proteins
- Promoter Regions, Genetic
- RNA/analysis
- Reverse Transcriptase Polymerase Chain Reaction
- Trans-Activators/genetics
- Trans-Activators/immunology
- Transcription, Genetic
- Transfection
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Affiliation(s)
- A K Tai
- The Schepens Eye Research Institute, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02114, USA
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Abdulkadir SA, Casolaro V, Tai AK, Thanos D, Ono SJ. High mobility group I/Y protein functions as a specific cofactor for Oct-2A: mapping of interaction domains. J Leukoc Biol 1998; 64:681-91. [PMID: 9823775 DOI: 10.1002/jlb.64.5.681] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The octamer motif (ATTTGCAT) present in several eukaryotic promoters and enhancers is now known to influence the transcription of several genes by interacting with members of a broad family of homeodomain proteins. The promoter of the human class II MHC gene HLA-DRA contains a conserved octamer element that can bind (among other proteins) the transcription factor Oct-2A and the high mobility group proteins (HMG) I/Y. We have previously determined that HMG I(Y) and Oct-2A cooperatively activate HLA-DRA gene expression, most likely due to the ability of HMG I(Y) to selectively recruit Oct-2A to the octamer motif. In this report, we present results of our investigations of the mechanisms of cooperative transactivation of HLA-DRA transcription by Oct-2A and HMG I(Y). We show that both the amino- and the carboxy-terminal domains of Oct-2A are required for HLA-DRA transactivation. Experiments using domain-swap chimeras of the Oct-1 and Oct-2A polypeptides indicate that cooperative activation of the DRA gene by HMG I(Y) and Oct-2A requires the carboxy-terminal domain (CTD) of Oct-2A. However, HMG I(Y) physically interacts with the conserved POU domains of both Oct-1 and Oct-2A. We therefore postulate that the nature of the CTD attached to the POU homeodomain influences the outcome of interaction with HMG I(Y). These studies support the view that HMG I(Y) is an important cofactor for HLA-DRA gene activation by Oct-2A and provide insights into its mechanism of action.
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Affiliation(s)
- S A Abdulkadir
- Laboratory of Molecular Immunology, The Schepens Eye Research Institute & Committee on Immunology, Harvard Medical School, Boston, Massachusetts 02114, USA
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