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Amarnani A, Lopez-Ocasio M, Dilshat R, Anumukonda K, Davila J, Malakhov N, Huan C, Magnusdottir E, Steingrimsson E, Roman CA. Mitf regulates gene expression networks implicated in B cell homeostasis, germinal center responses, and tolerance. Front Immunol 2024; 15:1339325. [PMID: 38444862 PMCID: PMC10912573 DOI: 10.3389/fimmu.2024.1339325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 01/08/2024] [Indexed: 03/07/2024] Open
Abstract
Introduction The microphthalmia transcription factor Mitf has been shown to regulate B cell activation and tolerance. However, the underlying B cell-specific mechanisms responsible, and those that distinguish Mitf from closely related Mitf/TFE (MiT) transcription factors Tfe3, Tfeb, and Tfec, remain obscure. Methods Two complementary mouse models of Mitf and MiT deficiency were used: the Mitfmi-vga9/mi-vga9 systemic loss-of-function mutation, and B-cell specific MiT family inactivation via transgenic expression of a trans-dominant negative (TDN) protein (TDN-B). These models were employed to identify MiT family candidate target genes and pathways. Results Both models displayed spontaneous splenomegaly coincident with elevated plasma cell numbers, autoantibody titers, and proteinuria. These abnormalities appeared dependent on T helper cells, but independent of other non-B cell intrinsic effects of systemic Mitf inactivation. MiT inactivation in B cells augmented aspects of lupus-like autoimmune disease on the C57BL/6-Faslpr/lpr background. In both models, RNAseq of ex vivo resting B cells showed transcriptional upregulation of genes that control cell cycle, germinal center responses, and plasma cell differentiation. Among the genes strongly upregulated in both models were Socs6, Isp53 (Baiap1), S1pR2, and IgG2b/c. Mitf null B cells, but not TDN-B cells, showed evidence of type I interferon dysregulation. Discussion These studies clarify Mitf's role as 1) a key regulator of a B cell intrinsic germinal center program that influences self-tolerance through novel target genes, and 2) a regulator of systemic inflammatory processes that can impact the B cell microenvironment. This distinction of Mitf's function from that of related MiT transcription factors advances our understanding of B cell regulation and autoimmunity.
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Affiliation(s)
- Abhimanyu Amarnani
- Program in Molecular and Cellular Biology, School of Graduate Studies, State University of New York (SUNY) Downstate Health Sciences University, Brooklyn, NY, United States
- School of Medicine, State University of New York (SUNY) Downstate Health Sciences University, Brooklyn, NY, United States
- Department of Medicine, Division of Rheumatology, New York University Langone Health, New York, NY, United States
| | - Maria Lopez-Ocasio
- Program in Molecular and Cellular Biology, School of Graduate Studies, State University of New York (SUNY) Downstate Health Sciences University, Brooklyn, NY, United States
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States
| | - Ramile Dilshat
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Biomedical Center, University of Iceland, Reykjavik, Iceland
| | - Kamala Anumukonda
- Program in Molecular and Cellular Biology, School of Graduate Studies, State University of New York (SUNY) Downstate Health Sciences University, Brooklyn, NY, United States
- Anuko Tech Inc., Hillsborough, NJ, United States
| | - Jonathan Davila
- School of Medicine, State University of New York (SUNY) Downstate Health Sciences University, Brooklyn, NY, United States
- Department of Urology, Northwell Health, Staten Island, NY, United States
| | - Nikita Malakhov
- School of Medicine, State University of New York (SUNY) Downstate Health Sciences University, Brooklyn, NY, United States
- Department of Hematology and Oncology, NewYork-Presbyterian-Weill Cornell Medical Center, New York, NY, United States
| | - Chongmin Huan
- Program in Molecular and Cellular Biology, School of Graduate Studies, State University of New York (SUNY) Downstate Health Sciences University, Brooklyn, NY, United States
| | - Erna Magnusdottir
- Department of Anatomy, Faculty of Medicine, Biomedical Center, University of Iceland, Reykjavik, Iceland
| | - Eirikur Steingrimsson
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Biomedical Center, University of Iceland, Reykjavik, Iceland
| | - Christopher A. Roman
- Program in Molecular and Cellular Biology, School of Graduate Studies, State University of New York (SUNY) Downstate Health Sciences University, Brooklyn, NY, United States
- School of Medicine, State University of New York (SUNY) Downstate Health Sciences University, Brooklyn, NY, United States
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2
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Chaudhari J, Liew CS, Workman AM, Riethoven JJM, Steffen D, Sillman S, Vu HLX. Host Transcriptional Response to Persistent Infection with a Live-Attenuated Porcine Reproductive and Respiratory Syndrome Virus Strain. Viruses 2020; 12:v12080817. [PMID: 32731586 PMCID: PMC7474429 DOI: 10.3390/v12080817] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/15/2020] [Accepted: 07/24/2020] [Indexed: 12/13/2022] Open
Abstract
Both virulent and live-attenuated porcine reproductive and respiratory syndrome virus (PRRSV) strains can establish persistent infection in lymphoid tissues of pigs. To investigate the mechanisms of PRRSV persistence, we performed a transcriptional analysis of inguinal lymphoid tissue collected from pigs experimentally infected with an attenuated PRRSV strain at 46 days post infection. A total of 6404 differentially expressed genes (DEGs) were detected of which 3960 DEGs were upregulated and 2444 DEGs were downregulated. Specifically, genes involved in innate immune responses and chemokines and receptors associated with T-cell homing to lymphoid tissues were down regulated. As a result, homing of virus-specific T-cells to lymphoid tissues seems to be ineffective, evidenced by the lower frequencies of virus-specific T-cell in lymphoid tissue than in peripheral blood. Genes associated with T-cell exhaustion were upregulated. Likewise, genes involved in the anti-apoptotic pathway were upregulated. Collectively, the data suggested that the live-attenuated PRRSV strain establishes a pro-survival microenvironment in lymphoid tissue by suppressing innate immune responses, T-cell homing, and preventing cell apoptosis.
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Affiliation(s)
- Jayeshbhai Chaudhari
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583, USA;
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, USA; (D.S.); (S.S.)
| | - Chia-Sin Liew
- Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE 68588, USA; (C.-S.L.); (J.-J.M.R.)
| | - Aspen M. Workman
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933, USA;
| | - Jean-Jack M. Riethoven
- Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE 68588, USA; (C.-S.L.); (J.-J.M.R.)
| | - David Steffen
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, USA; (D.S.); (S.S.)
| | - Sarah Sillman
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, USA; (D.S.); (S.S.)
| | - Hiep L. X. Vu
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583, USA;
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
- Correspondence: ; Tel.: +1-402-472-4528
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Gupta G, Deval R, Mishra A, Upadhyay S, Singh PK, Rao VR. Re-testing reported significant SNPs related to suicide in a historical high -risk isolated population from north east India. Hereditas 2020; 157:31. [PMID: 32680568 PMCID: PMC7368720 DOI: 10.1186/s41065-020-00144-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 07/07/2020] [Indexed: 02/08/2023] Open
Abstract
Background Genetic diathesis of suicide is supported by family and twin studies. Few candidate gene pathways are known, but does not explain fully the complexity of suicide genetic risk. Recent investigations opting for Genome-Wide Association Studies (GWAS) resulted in finding additional targets, but replication remained a challenge. In this respect small isolated population approach in several complex disease phenotypes is found encouraging. The present study is an attempt to re-test some of the reported significant SNPs for suicide among a small historical high- risk isolated population from Northeast India. Methods Two hundred ten cases (inclusive of depressed, suicide attempter and depressed + suicide attempter) and 249 controls were considered in the present study which were evaluated for the psychiatric parameters. Sixteen reported significant SNPs for suicide behaviour were re-tested using association approach under various genetic models. Networking by GeneMANIA tool was used for function prediction of the associated genes. Results Seven SNPs (of 6 genes) remained significant in different genetic models. On networking genes with significant SNPs IL7, RHEB, CTNN3, KCNIP4, ARFGEF3 are found in interaction with already known candidate gene pathways while SNP rs1109089 (RHEB) gained further support from earlier expression studies. NUGGC gene is in complete isolation. Conclusions Small population approach in replicating significant SNPs is useful in complex phenotypes like suicide. This study explored the region-specific demographics of India by identifying vulnerable population for suicide via genetic association analysis in bringing into academic and administrative forum, the importance of suicide as a disease and its biological basis.
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Affiliation(s)
- Gaurav Gupta
- Department of Biotechnology, Invertis University, Bareilly (U.P), India.,Department of Genetics, Osmania University, Hyderabad, 500007, India
| | - Ravi Deval
- Department of Biotechnology, Invertis University, Bareilly (U.P), India
| | - Anshuman Mishra
- VBRI Innovation Centre, New Delhi, India.,Institute of Advanced Materials (IAAM), 59053, Ulrika, Sweden
| | - Shashank Upadhyay
- Department of Biotechnology, Invertis University, Bareilly (U.P), India
| | - Piyoosh Kumar Singh
- Department of Anthropology, Delhi University, Delhi, India.,Department of Psychiatry, All India Institute of Medical Sciences, New Delhi, India
| | - V R Rao
- Department of Genetics, Osmania University, Hyderabad, 500007, India. .,Department of Anthropology, Delhi University, Delhi, India. .,Genome Foundation, Hyderabad, India.
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Quantitative trait loci and genes associated with salmonid alphavirus load in Atlantic salmon: implications for pancreas disease resistance and tolerance. Sci Rep 2020; 10:10393. [PMID: 32587341 PMCID: PMC7316828 DOI: 10.1038/s41598-020-67405-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 06/08/2020] [Indexed: 12/22/2022] Open
Abstract
Salmonid alphavirus infection results in pancreas disease causing severe economic losses for Atlantic salmon aquaculture. Knowledge about genes and pathways contributing to resistance is limited. A 54 K SNP panel was used to genotype 10 full-sibling families each consisting of ~ 110 offspring challenged with salmonid alphavirus subtype 3. Relative heart viral load was assessed at 4- and 10-weeks post-infection using quantitative PCR. A moderate genomic heritability of viral load at 4 weeks (0.15–0.21) and a high positive correlation with survival (0.91–0.98) were detected. Positions of QTL detected on chromosome 3 matched those for survival detected by other studies. The SNP of highest significance occurred in the 3′ untranslated region of gig1, a fish-specific antiviral effector. Locus B of immunoglobulin heavy chain mapped to an area containing multiple SNPs with genome-wide association. Heart mRNA-seq comparing parr from families with high- versus low-genomic breeding value, and matching sample genotypes for SNPs, identified two eQTL for salmonid alphavirus load. Immune genes associated with trans-eQTL were numerous and spread throughout the genome. QTL regions contained several genes with known or predicted immune functions, some differentially expressed. The putative functional genes and variants identified could help improve marker-based selection for pancreas disease resistance.
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Robinson NA, Krasnov A, Burgerhout E, Johnsen H, Moghadam HK, Hillestad B, Aslam ML, Baranski M, Boison SA. Response of the Salmon Heart Transcriptome to Pancreas Disease: Differences Between High- and Low-Ranking Families for Resistance. Sci Rep 2020; 10:868. [PMID: 31964968 PMCID: PMC6972705 DOI: 10.1038/s41598-020-57786-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 01/07/2020] [Indexed: 12/30/2022] Open
Abstract
Pancreas disease caused by salmonid alphaviruses leads to severe losses in Atlantic salmon aquaculture. The aim of our study was to gain a better understanding of the biological differences between salmon with high and low genomic breeding values (H-gEBV and L-gEBV respectively) for pancreas disease resistance. Fish from H- and L-gEBV families were challenged by intraperitoneal injection of salmonid alphavirus or co-habitation with infected fish. Mortality was higher with co-habitation than injection, and for L- than H-gEBV. Heart for RNA-seq and histopathology was collected before challenge and at four- and ten-weeks post-challenge. Heart damage was less severe in injection-challenged H- than L-gEBV fish at week 4. Viral load was lower in H- than L-gEBV salmon after co-habitant challenge. Gene expression differences between H- and L-gEBV manifested before challenge, peaked at week 4, and moderated by week 10. At week 4, H-gEBV salmon showed lower expression of innate antiviral defence genes, stimulation of B- and T-cell immune function, and weaker stress responses. Retarded resolution of the disease explains the higher expression of immune genes in L-gEBV at week 10. Results suggest earlier mobilization of acquired immunity better protects H-gEBV salmon by accelerating clearance of the virus and resolution of the disease.
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Affiliation(s)
- N A Robinson
- Breeding and Genetics, Nofima, Ås, 1430, Norway. .,Sustainable Aquaculture Laboratory- Temperate and Tropical (SALTT), School of BioSciences, The University of Melbourne, Parkville, 3010, Australia.
| | - A Krasnov
- Breeding and Genetics, Nofima, Ås, 1430, Norway
| | | | - H Johnsen
- Breeding and Genetics, Nofima, Ås, 1430, Norway
| | | | | | - M L Aslam
- Breeding and Genetics, Nofima, Ås, 1430, Norway
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Ren J, Catalina MD, Eden K, Liao X, Read KA, Luo X, McMillan RP, Hulver MW, Jarpe M, Bachali P, Grammer AC, Lipsky PE, Reilly CM. Selective Histone Deacetylase 6 Inhibition Normalizes B Cell Activation and Germinal Center Formation in a Model of Systemic Lupus Erythematosus. Front Immunol 2019; 10:2512. [PMID: 31708928 PMCID: PMC6823248 DOI: 10.3389/fimmu.2019.02512] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 10/08/2019] [Indexed: 01/25/2023] Open
Abstract
Autoantibody production by plasma cells (PCs) plays a pivotal role in the pathogenesis of systemic lupus erythematosus (SLE). The molecular pathways by which B cells become pathogenic PC secreting autoantibodies in SLE are incompletely characterized. Histone deactylase 6 (HDAC6) is a unique cytoplasmic HDAC that modifies the interaction of a number of tubulin- associated proteins; inhibition of HDAC6 has been shown to be beneficial in murine models of SLE, but the downstream pathways accounting for the therapeutic benefit have not been clearly delineated. In the current study, we sought to determine whether selective HDAC6 inhibition would abrogate abnormal B cell activation in SLE. We treated NZB/W lupus mice with the selective HDAC6 inhibitor, ACY-738, for 4 weeks beginning at 20 weeks-of age. After only 4 weeks of treatment, manifestation of lupus nephritis (LN) were greatly reduced in these animals. We then used RNAseq to determine the genomic signatures of splenocytes from treated and untreated mice and applied computational cellular and pathway analysis to reveal multiple signaling events associated with B cell activation and differentiation in SLE that were modulated by HDAC6 inhibition. PC development was abrogated and germinal center (GC) formation was greatly reduced. When the HDAC6 inhibitor-treated lupus mouse gene signatures were compared to human lupus patient gene signatures, the results showed numerous immune, and inflammatory pathways increased in active human lupus were significantly decreased in the HDAC6 inhibitor treated animals. Pathway analysis suggested alterations in cellular metabolism might contribute to the normalization of lupus mouse spleen genomic signatures, and this was confirmed by direct measurement of the impact of the HDAC6 inhibitor on metabolic activities of murine spleen cells. Taken together, these studies show HDAC6 inhibition decreases B cell activation signaling pathways and reduces PC differentiation in SLE and suggest that a critical event might be modulation of cellular metabolism.
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Affiliation(s)
- Jingjing Ren
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Michelle D Catalina
- AMPEL BioSolutions, Charlottesville, VA, United States.,RILITE Research Institute, Charlottesville, VA, United States
| | - Kristin Eden
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Xiaofeng Liao
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Kaitlin A Read
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States.,Virginia Tech Carilion Research Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Xin Luo
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Ryan P McMillan
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Matthew W Hulver
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Matthew Jarpe
- Regenacy Pharmaceuticals, Waltham, MA, United States
| | | | - Amrie C Grammer
- AMPEL BioSolutions, Charlottesville, VA, United States.,RILITE Research Institute, Charlottesville, VA, United States
| | - Peter E Lipsky
- AMPEL BioSolutions, Charlottesville, VA, United States.,RILITE Research Institute, Charlottesville, VA, United States
| | - Christopher M Reilly
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States.,Edward Via College of Osteopathic Medicine, Blacksburg, VA, United States
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7
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Verkoczy L. Humanized Immunoglobulin Mice: Models for HIV Vaccine Testing and Studying the Broadly Neutralizing Antibody Problem. Adv Immunol 2017; 134:235-352. [PMID: 28413022 PMCID: PMC5914178 DOI: 10.1016/bs.ai.2017.01.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A vaccine that can effectively prevent HIV-1 transmission remains paramount to ending the HIV pandemic, but to do so, will likely need to induce broadly neutralizing antibody (bnAb) responses. A major technical hurdle toward achieving this goal has been a shortage of animal models with the ability to systematically pinpoint roadblocks to bnAb induction and to rank vaccine strategies based on their ability to stimulate bnAb development. Over the past 6 years, immunoglobulin (Ig) knock-in (KI) technology has been leveraged to express bnAbs in mice, an approach that has enabled elucidation of various B-cell tolerance mechanisms limiting bnAb production and evaluation of strategies to circumvent such processes. From these studies, in conjunction with the wealth of information recently obtained regarding the evolutionary pathways and paratopes/epitopes of multiple bnAbs, it has become clear that the very features of bnAbs desired for their function will be problematic to elicit by traditional vaccine paradigms, necessitating more iterative testing of new vaccine concepts. To meet this need, novel bnAb KI models have now been engineered to express either inferred prerearranged V(D)J exons (or unrearranged germline V, D, or J segments that can be assembled into functional rearranged V(D)J exons) encoding predecessors of mature bnAbs. One encouraging approach that has materialized from studies using such newer models is sequential administration of immunogens designed to bind progressively more mature bnAb predecessors. In this review, insights into the regulation and induction of bnAbs based on the use of KI models will be discussed, as will new Ig KI approaches for higher-throughput production and/or altering expression of bnAbs in vivo, so as to further enable vaccine-guided bnAb induction studies.
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Affiliation(s)
- Laurent Verkoczy
- Duke University Human Vaccine Institute, Duke University School of Medicine, Durham, NC, United States.
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8
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Transcriptomic Analysis of Persistent Infection with Foot-and-Mouth Disease Virus in Cattle Suggests Impairment of Apoptosis and Cell-Mediated Immunity in the Nasopharynx. PLoS One 2016; 11:e0162750. [PMID: 27643611 PMCID: PMC5028045 DOI: 10.1371/journal.pone.0162750] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 08/26/2016] [Indexed: 12/15/2022] Open
Abstract
In order to investigate the mechanisms of persistent foot-and-mouth disease virus (FMDV) infection in cattle, transcriptome alterations associated with the FMDV carrier state were characterized using a bovine whole-transcriptome microarray. Eighteen cattle (8 vaccinated with a recombinant FMDV A vaccine, 10 non-vaccinated) were challenged with FMDV A24 Cruzeiro, and the gene expression profiles of nasopharyngeal tissues collected between 21 and 35 days after challenge were compared between 11 persistently infected carriers and 7 non-carriers. Carriers and non-carriers were further compared to 2 naïve animals that had been neither vaccinated nor challenged. At a controlled false-discovery rate of 10% and a minimum difference in expression of 50%, 648 genes were differentially expressed between FMDV carriers and non-carriers, and most (467) had higher expression in carriers. Among these, genes associated with cellular proliferation and the immune response-such as chemokines, cytokines and genes regulating T and B cells-were significantly overrepresented. Differential gene expression was significantly correlated between non-vaccinated and vaccinated animals (biological correlation +0.97), indicating a similar transcriptome profile across these groups. Genes related to prostaglandin E2 production and the induction of regulatory T cells were overexpressed in carriers. In contrast, tissues from non-carrier animals expressed higher levels of complement regulators and pro-apoptotic genes that could promote virus clearance. Based on these findings, we propose a working hypothesis for FMDV persistence in nasopharyngeal tissues of cattle, in which the virus may be maintained by an impairment of apoptosis and the local suppression of cell-mediated antiviral immunity by inducible regulatory T cells.
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Meng FL, Du Z, Federation A, Hu J, Wang Q, Kieffer-Kwon KR, Meyers RM, Amor C, Wasserman CR, Neuberg D, Casellas R, Nussenzweig MC, Bradner JE, Liu XS, Alt FW. Convergent transcription at intragenic super-enhancers targets AID-initiated genomic instability. Cell 2014; 159:1538-48. [PMID: 25483776 PMCID: PMC4322776 DOI: 10.1016/j.cell.2014.11.014] [Citation(s) in RCA: 188] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 10/01/2014] [Accepted: 10/27/2014] [Indexed: 01/08/2023]
Abstract
Activation-induced cytidine deaminase (AID) initiates both somatic hypermutation (SHM) for antibody affinity maturation and DNA breakage for antibody class switch recombination (CSR) via transcription-dependent cytidine deamination of single-stranded DNA targets. Though largely specific for immunoglobulin genes, AID also acts on a limited set of off-targets, generating oncogenic translocations and mutations that contribute to B cell lymphoma. How AID is recruited to off-targets has been a long-standing mystery. Based on deep GRO-seq studies of mouse and human B lineage cells activated for CSR or SHM, we report that most robust AID off-target translocations occur within highly focal regions of target genes in which sense and antisense transcription converge. Moreover, we found that such AID-targeting "convergent" transcription arises from antisense transcription that emanates from super-enhancers within sense transcribed gene bodies. Our findings provide an explanation for AID off-targeting to a small subset of mostly lineage-specific genes in activated B cells.
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Affiliation(s)
- Fei-Long Meng
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Zhou Du
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Department of Bioinformatics, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Alexander Federation
- Department of Medical Oncology, Dana-Farber Cancer Institute, and Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Jiazhi Hu
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Qiao Wang
- Howard Hughes Medical Institute, Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Kyong-Rim Kieffer-Kwon
- Genomics and Immunity, NIAMS, and Center of Cancer Research, NCI, National Institutes of Health, Bethesda, MD 20892, USA
| | - Robin M Meyers
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Corina Amor
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Caitlyn R Wasserman
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Donna Neuberg
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute and Harvard School of Public Health, Boston, MA 02115, USA
| | - Rafael Casellas
- Genomics and Immunity, NIAMS, and Center of Cancer Research, NCI, National Institutes of Health, Bethesda, MD 20892, USA
| | - Michel C Nussenzweig
- Howard Hughes Medical Institute, Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - James E Bradner
- Department of Medical Oncology, Dana-Farber Cancer Institute, and Department of Medicine, Harvard Medical School, Boston, MA 02115, USA.
| | - X Shirley Liu
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute and Harvard School of Public Health, Boston, MA 02115, USA
| | - Frederick W Alt
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
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Meehan TF, Vasilevsky NA, Mungall CJ, Dougall DS, Haendel MA, Blake JA, Diehl AD. Ontology based molecular signatures for immune cell types via gene expression analysis. BMC Bioinformatics 2013; 14:263. [PMID: 24004649 PMCID: PMC3844401 DOI: 10.1186/1471-2105-14-263] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 08/21/2013] [Indexed: 12/15/2022] Open
Abstract
Background New technologies are focusing on characterizing cell types to better understand their heterogeneity. With large volumes of cellular data being generated, innovative methods are needed to structure the resulting data analyses. Here, we describe an ‘Ontologically BAsed Molecular Signature’ (OBAMS) method that identifies novel cellular biomarkers and infers biological functions as characteristics of particular cell types. This method finds molecular signatures for immune cell types based on mapping biological samples to the Cell Ontology (CL) and navigating the space of all possible pairwise comparisons between cell types to find genes whose expression is core to a particular cell type’s identity. Results We illustrate this ontological approach by evaluating expression data available from the Immunological Genome project (IGP) to identify unique biomarkers of mature B cell subtypes. We find that using OBAMS, candidate biomarkers can be identified at every strata of cellular identity from broad classifications to very granular. Furthermore, we show that Gene Ontology can be used to cluster cell types by shared biological processes in order to find candidate genes responsible for somatic hypermutation in germinal center B cells. Moreover, through in silico experiments based on this approach, we have identified genes sets that represent genes overexpressed in germinal center B cells and identify genes uniquely expressed in these B cells compared to other B cell types. Conclusions This work demonstrates the utility of incorporating structured ontological knowledge into biological data analysis – providing a new method for defining novel biomarkers and providing an opportunity for new biological insights.
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Affiliation(s)
- Terrence F Meehan
- Department of Neurology, University at Buffalo School of Medicine and Biomedical Sciences, 100 High Street, Buffalo, NY 14203, USA.
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Richter K, Burch L, Chao F, Henke D, Jiang C, Daly J, Zhao ML, Kissling G, Diaz M. Altered pattern of immunoglobulin hypermutation in mice deficient in Slip-GC protein. J Biol Chem 2012; 287:31856-65. [PMID: 22833677 DOI: 10.1074/jbc.m112.340661] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We recently identified a novel germinal center GTPase, SLIP-GC, that localizes to replication factories in B cells and that, when reduced, induces DNA breaks in lymphoma B cell lines in an activation-induced deaminase (AID)-dependent manner. Herein, we generated mice deficient in SLIP-GC and examined the impact of SLIP-GC deficiency in immunoglobulin hypermutation and class switch recombination, both AID-dependent mechanisms. SLIP-GC-deficient mice experienced a substantial increase in mutations at G:C base pairs at the region downstream of JH4 in the immunoglobulin heavy chain locus. This change was reflected in the overall mutation frequency, and it was associated with an increase in transitions from G:C base pairs, a hallmark of AID-mediated deamination during replication. In addition, G:C transitions at non-immunoglobulin loci also increased in these mice. Given the intracellular localization of SLIP-GC to sites of replicating DNA, these results suggest that SLIP-GC protects replicating DNA from AID-mediated deamination of cytosines in both strands.
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Affiliation(s)
- Kathleen Richter
- Somatic Hypermutation Group, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
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Deeb SJ, D'Souza RCJ, Cox J, Schmidt-Supprian M, Mann M. Super-SILAC allows classification of diffuse large B-cell lymphoma subtypes by their protein expression profiles. Mol Cell Proteomics 2012; 11:77-89. [PMID: 22442255 PMCID: PMC3418848 DOI: 10.1074/mcp.m111.015362] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Correct classification of cancer patients into subtypes is a prerequisite for acute diagnosis and effective treatment. Currently this classification relies mainly on histological assessment, but gene expression analysis by microarrays has shown great promise. Here we show that high accuracy, quantitative proteomics can robustly segregate cancer subtypes directly at the level of expressed proteins. We investigated two histologically indistinguishable subtypes of diffuse large B-cell lymphoma (DLBCL): activated B-cell-like (ABC) and germinal-center B-cell-like (GCB) subtypes, by first developing a general lymphoma stable isotope labeling with amino acids in cell culture (SILAC) mix from heavy stable isotope-labeled cell lines. This super-SILAC mix was combined with cell lysates from five ABC-DLBCL and five GCB-DLBCL cell lines. Shotgun proteomic analysis on a linear ion trap Orbitrap mass spectrometer with high mass accuracy at the MS and MS/MS levels yielded a proteome of more than 7,500 identified proteins. High accuracy of quantification allowed robust separation of subtypes by principal component analysis. The main contributors to the classification included proteins known to be differentially expressed between the subtypes such as the transcription factors IRF4 and SPI1/PU.1, cell surface markers CD44 and CD27, as well as novel candidates. We extracted a signature of 55 proteins that segregated subtypes and contained proteins connected to functional differences between the ABC and GCB-DLBCL subtypes, including many NF-κB-regulated genes. Shortening the analysis time to single-shot analysis combined with use of the new linear quadrupole Orbitrap analyzer (Q Exactive) also clearly differentiated between the subtypes. These results show that high resolution shotgun proteomics combined with super-SILAC-based quantification is a promising new technology for tumor characterization and classification.
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Affiliation(s)
- Sally J Deeb
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
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Identification and characterization of a leucine-rich repeat kinase 2 (LRRK2) consensus phosphorylation motif. PLoS One 2010; 5:e13672. [PMID: 21060682 PMCID: PMC2965117 DOI: 10.1371/journal.pone.0013672] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 10/05/2010] [Indexed: 01/01/2023] Open
Abstract
Mutations in LRRK2 (leucine-rich repeat kinase 2) have been identified as major genetic determinants of Parkinson's disease (PD). The most prevalent mutation, G2019S, increases LRRK2's kinase activity, therefore understanding the sites and substrates that LRRK2 phosphorylates is critical to understanding its role in disease aetiology. Since the physiological substrates of this kinase are unknown, we set out to reveal potential targets of LRRK2 G2019S by identifying its favored phosphorylation motif. A non-biased screen of an oriented peptide library elucidated F/Y-x-T-x-R/K as the core dependent substrate sequence. Bioinformatic analysis of the consensus phosphorylation motif identified several novel candidate substrates that potentially function in neuronal pathophysiology. Peptides corresponding to the most PD relevant proteins were efficiently phosphorylated by LRRK2 in vitro. Interestingly, the phosphomotif was also identified within LRRK2 itself. Autophosphorylation was detected by mass spectrometry and biochemical means at the only F-x-T-x-R site (Thr 1410) within LRRK2. The relevance of this site was assessed by measuring effects of mutations on autophosphorylation, kinase activity, GTP binding, GTP hydrolysis, and LRRK2 multimerization. These studies indicate that modification of Thr1410 subtly regulates GTP hydrolysis by LRRK2, but with minimal effects on other parameters measured. Together the identification of LRRK2's phosphorylation consensus motif, and the functional consequences of its phosphorylation, provide insights into downstream LRRK2-signaling pathways.
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