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Florini F, Visone JE, Hadjimichael E, Malpotra S, Nötzel C, Kafsack BF, Deitsch KW. Transcriptional plasticity of virulence genes provides malaria parasites with greater adaptive capacity for avoiding host immunity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.08.584127. [PMID: 38496509 PMCID: PMC10942408 DOI: 10.1101/2024.03.08.584127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Chronic, asymptomatic malaria infections contribute substantially to disease transmission and likely represent the most significant impediment preventing malaria elimination and eradication. Plasmodium falciparum parasites evade antibody recognition through transcriptional switching between members of the var gene family, which encodes the major virulence factor and surface antigen on infected red blood cells. This process can extend infections for up to a year; however, infections have been documented to last for over a decade, constituting an unseen reservoir of parasites that undermine eradication and control efforts. How parasites remain immunologically "invisible" for such lengthy periods is entirely unknown. Here we show that in addition to the accepted paradigm of mono-allelic var gene expression, individual parasites can simultaneously express multiple var genes or enter a state in which little or no var gene expression is detectable. This unappreciated flexibility provides parasites with greater adaptive capacity than previously understood and challenges the dogma of mutually exclusive var gene expression. It also provides an explanation for the antigenically "invisible" parasites observed in chronic asymptomatic infections.
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Affiliation(s)
| | | | - Evi Hadjimichael
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
| | - Shivali Malpotra
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
| | | | - Björn F.C. Kafsack
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
| | - Kirk W. Deitsch
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
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Reyes RA, Raghavan SSR, Hurlburt NK, Introini V, Kana IH, Jensen RW, Martinez-Scholze E, Gestal-Mato M, Bau CB, Fernández-Quintero ML, Loeffler JR, Ferguson JA, Lee WH, Martin GM, Theander TG, Ssewanyana I, Feeney ME, Greenhouse B, Bol S, Ward AB, Bernabeu M, Pancera M, Turner L, Bunnik EM, Lavstsen T. Broadly inhibitory antibodies against severe malaria virulence proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.25.577124. [PMID: 38328068 PMCID: PMC10849712 DOI: 10.1101/2024.01.25.577124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Plasmodium falciparum pathology is driven by the accumulation of parasite-infected erythrocytes in microvessels. This process is mediated by the parasite's polymorphic erythrocyte membrane protein 1 (PfEMP1) adhesion proteins. A subset of PfEMP1 variants that bind human endothelial protein C receptor (EPCR) through their CIDRα1 domains is responsible for severe malaria pathogenesis. A longstanding question is whether individual antibodies can recognize the large repertoire of circulating PfEMP1 variants. Here, we describe two broadly reactive and binding-inhibitory human monoclonal antibodies against CIDRα1. The antibodies isolated from two different individuals exhibited a similar and consistent EPCR-binding inhibition of 34 CIDRα1 domains, representing five of the six subclasses of CIDRα1. Both antibodies inhibited EPCR binding of both recombinant full-length and native PfEMP1 proteins as well as parasite sequestration in bioengineered 3D brain microvessels under physiologically relevant flow conditions. Structural analyses of the two antibodies in complex with two different CIDRα1 antigen variants reveal similar binding mechanisms that depend on interactions with three highly conserved amino acid residues of the EPCR-binding site in CIDRα1. These broadly reactive antibodies likely represent a common mechanism of acquired immunity to severe malaria and offer novel insights for the design of a vaccine or treatment targeting severe malaria.
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Affiliation(s)
- Raphael A. Reyes
- Department of Microbiology, Immunology and Molecular Genetics, Long School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Sai Sundar Rajan Raghavan
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Nicholas K. Hurlburt
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Viola Introini
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona 08003, Spain
| | - Ikhlaq Hussain Kana
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
| | - Rasmus W. Jensen
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
| | - Elizabeth Martinez-Scholze
- Department of Microbiology, Immunology and Molecular Genetics, Long School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Maria Gestal-Mato
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona 08003, Spain
| | | | | | - Johannes R. Loeffler
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - James Alexander Ferguson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Wen-Hsin Lee
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Greg Michael Martin
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Thor G. Theander
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
| | | | - Margaret E. Feeney
- Department of Medicine, University of California San Francisco, San Francisco, CA 94110, USA
- Department of Pediatrics, University of California San Francisco, San Francisco, CA 94110, USA
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, CA 94110, USA
| | - Sebastiaan Bol
- Department of Microbiology, Immunology and Molecular Genetics, Long School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Andrew B. Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Maria Bernabeu
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona 08003, Spain
| | - Marie Pancera
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Louise Turner
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
| | - Evelien M. Bunnik
- Department of Microbiology, Immunology and Molecular Genetics, Long School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Thomas Lavstsen
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
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Zhou Y, Liu H, Wu T, Zheng Y, Wang R, Xue D, Yan Q, Yuan X, Chen X. Screening of Reference Genes under Biotic Stress and Hormone Treatment of Mung Bean ( Vigna radiata) by Quantitative Real-Time PCR. Genes (Basel) 2023; 14:1739. [PMID: 37761879 PMCID: PMC10530681 DOI: 10.3390/genes14091739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 08/26/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
Mung bean (Vigna radiata) production has been greatly threatened by numerous diseases. Infection with these pathogens causes extensive changes in gene expression and the activation of hormone signal transduction. Quantitative real-time PCR (qRT-PCR) is the most common technique used for gene expression validation. Screening proper reference genes for mung bean under pathogen infection and hormone treatment is a prerequisite for ensuring the accuracy of qRT-PCR data in mung bean disease-resistance research. In this study, six candidate reference genes (Cons4, ACT, TUA, TUB, GAPDH, and EF1α) were selected to evaluate the expression stability under four soil-borne disease pathogens (Pythium myriotylum, Pythium aphanidermatum, Fusarium oxysporum, and Rhizoctonia solani) and five hormone treatments (SA, MeJA, ETH, ABA, and GA3). In the samples from different treatments, the Ct value distribution of the six candidate reference genes was different. Under the condition of hormone treatment, the Ct value ranged from a minimum of 17.87 for EF1α to a maximum of 29.63 for GAPDH. Under the condition of pathogen infection, the Ct value ranged from a minimum of 19.43 for EF1α to a maximum of 31.82 for GAPDH. After primer specificity analysis, it was found that GAPDH was not specific, so the five reference genes Cons4, ACT, TUA, TUB, and EF1α were used in subsequent experiments. The software products GeNorm, NormFinder, BestKeeper and RefFinder were used for qRT-PCR data analysis. In general, the best candidates reference genes were: TUA for SA, ABA, GA3, and Pythium myriotylum treatment; TUB for ETH treatment; ACT for MeJA and Fusarium oxysporum treatment; and EF1α for Pythium aphanidermatum and Rhizoctonia solani treatment. The most stably expressed genes in all samples were TUA, while Cons4 was the least stable reference gene. Finally, the reliability of the reference gene was further validated by analysis of the expression profiles of four mung bean genes (Vradi0146s00260, Vradi0158s00480, Vradi07g23860, and Vradi11g03350) selected from transcriptome data. Our results provide more accurate information for the normalization of qRT-PCR data in mung bean response to pathogen interaction.
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Affiliation(s)
- Yanyan Zhou
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China (H.L.)
| | - Huan Liu
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China (H.L.)
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, China
| | - Ting Wu
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China (H.L.)
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, China
| | - Yu Zheng
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, China
- School of Life Sciences, Jiangsu University, Zhenjiang 212013, China
| | - Ruimin Wang
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, China
| | - Dong Xue
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, China
| | - Qiang Yan
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, China
| | - Xingxing Yuan
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China (H.L.)
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, China
| | - Xin Chen
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China (H.L.)
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, China
- School of Life Sciences, Jiangsu University, Zhenjiang 212013, China
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