1
|
Cao Y, Hayashi CTH, Kumar N. A Novel Ex Vivo Assay to Evaluate Functional Effectiveness of Plasmodium vivax Transmission-Blocking Vaccine Using Pvs25 Transgenic Plasmodium berghei. J Infect Dis 2024; 229:1894-1903. [PMID: 38408353 PMCID: PMC11175679 DOI: 10.1093/infdis/jiae102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 01/20/2024] [Accepted: 02/22/2024] [Indexed: 02/28/2024] Open
Abstract
BACKGROUND Plasmodium falciparum and Plasmodium vivax account for >90% global malaria burden. Transmission intervention strategies encompassing transmission-blocking vaccines (TBV) and drugs represent ideal public health tools to eliminate malaria at the population level. The availability of mature P. falciparum gametocytes through in vitro culture has facilitated development of a standard membrane feeding assay to assess efficacy of transmission interventions against P. falciparum. The lack of in vitro culture for P. vivax has significantly hampered similar progress on P. vivax and limited studies have been possible using blood from infected patients in endemic areas. The ethical and logistical limitations of on-time access to blood from patients have impeded the development of P. vivax TBVs. METHODS Transgenic murine malaria parasites (Plasmodium berghei) expressing TBV candidates offer a promising alternative for evaluation of P. vivax TBVs through in vivo studies in mice, and ex vivo membrane feeding assay (MFA). RESULTS We describe the development of transmission-competent transgenic TgPbvs25 parasites and optimization of parameters to establish an ex vivo MFA to evaluate P. vivax TBV based on Pvs25 antigen. CONCLUSIONS The MFA is expected to expedite Pvs25-based TBV development without dependence on blood from P. vivax-infected patients in endemic areas for evaluation.
Collapse
Affiliation(s)
- Yi Cao
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, District of Columbia, USA
| | - Clifford T H Hayashi
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, District of Columbia, USA
| | - Nirbhay Kumar
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, District of Columbia, USA
| |
Collapse
|
2
|
Silva MG, Bastos RG, Laughery JM, Alzan HF, Rathinasamy VA, Cooke BM, Suarez CE. Vaccination of cattle with the Babesia bovis sexual-stage protein HAP2 abrogates parasite transmission by Rhipicephalus microplus ticks. NPJ Vaccines 2023; 8:140. [PMID: 37758790 PMCID: PMC10533483 DOI: 10.1038/s41541-023-00741-8] [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: 03/29/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023] Open
Abstract
The apicomplexan parasite Babesia bovis is responsible for bovine babesiosis, a poorly controlled tick-borne disease of global impact. The widely conserved gametocyte protein HAPLESS2/GCS1 (HAP2) is uniquely expressed on the surface of B. bovis sexual stage parasites and is a candidate for transmission-blocking vaccines (TBV). Here, we tested whether vaccination of calves with recombinant HAP2 (rHAP2) interferes with the transmission of B. bovis by competent ticks. Calves vaccinated with rHAP2 (n = 3), but not control animals (n = 3) developed antibodies specific to the vaccine antigen. Vaccinated and control animals were infested with Rhipicephalus microplus larvae and subsequently infected with virulent blood stage B. bovis parasites by needle inoculation, with all animals developing clinical signs of acute babesiosis. Engorged female ticks fed on the infected calves were collected for oviposition, hatching, and obtention of larvae. Transmission feeding was then conducted using pools of larvae derived from ticks fed on rHAP2-vaccinated or control calves. Recipient calves (n = 3) exposed to larvae derived from control animals, but none of the recipient calves (n = 3) challenged with larvae from ticks fed on rHAP2-vaccinated animals, developed signs of acute babesiosis within 11 days after tick infestation. Antibodies against B. bovis antigens and parasite DNA were found in all control recipient animals, but not in any of the calves exposed to larvae derived from HAP2-vaccinated animals, consistent with the absence of B. bovis infection via tick transmission. Overall, our results are consistent with the abrogation of parasite tick transmission in rHAP2-vaccinated calves, confirming this antigen as a prime TBV candidate against B. bovis.
Collapse
Affiliation(s)
- Marta G Silva
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - Reginaldo G Bastos
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
- Animal Disease Research Unit, United States Department of Agricultural - Agricultural Research Service, Pullman, WA, USA
| | - Jacob M Laughery
- Animal Disease Research Unit, United States Department of Agricultural - Agricultural Research Service, Pullman, WA, USA
| | - Heba F Alzan
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
- Parasitology and Animal Diseases Department, National Research Center, Dokki, Giza, Egypt
| | - Vignesh A Rathinasamy
- Australian Institute of Tropical Health & Medicine, James Cook University, Cairns, QLD, Australia
| | - Brian M Cooke
- Australian Institute of Tropical Health & Medicine, James Cook University, Cairns, QLD, Australia
| | - Carlos E Suarez
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, USA.
- Animal Disease Research Unit, United States Department of Agricultural - Agricultural Research Service, Pullman, WA, USA.
| |
Collapse
|
3
|
Azimi FC, Dean TT, Minari K, Basso LGM, Vance TDR, Serrão VHB. A Frame-by-Frame Glance at Membrane Fusion Mechanisms: From Viral Infections to Fertilization. Biomolecules 2023; 13:1130. [PMID: 37509166 PMCID: PMC10377500 DOI: 10.3390/biom13071130] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/09/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023] Open
Abstract
Viral entry and fertilization are distinct biological processes that share a common mechanism: membrane fusion. In viral entry, enveloped viruses attach to the host cell membrane, triggering a series of conformational changes in the viral fusion proteins. This results in the exposure of a hydrophobic fusion peptide, which inserts into the host membrane and brings the viral and host membranes into close proximity. Subsequent structural rearrangements in opposing membranes lead to their fusion. Similarly, membrane fusion occurs when gametes merge during the fertilization process, though the exact mechanism remains unclear. Structural biology has played a pivotal role in elucidating the molecular mechanisms underlying membrane fusion. High-resolution structures of the viral and fertilization fusion-related proteins have provided valuable insights into the conformational changes that occur during this process. Understanding these mechanisms at a molecular level is essential for the development of antiviral therapeutics and tools to influence fertility. In this review, we will highlight the biological importance of membrane fusion and how protein structures have helped visualize both common elements and subtle divergences in the mechanisms behind fusion; in addition, we will examine the new tools that recent advances in structural biology provide researchers interested in a frame-by-frame understanding of membrane fusion.
Collapse
Affiliation(s)
- Farshad C. Azimi
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada;
| | - Trevor T. Dean
- Pharmaceutical Sciences, University of Illinois Chicago, Chicago, IL 60612, USA;
| | - Karine Minari
- Biomolecular Cryo-Electron Microscopy Facility, University of California-Santa Cruz, Santa Cruz, CA 95064, USA;
| | - Luis G. M. Basso
- Laboratório de Ciências Físicas, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro 28013-602, Brazil;
| | - Tyler D. R. Vance
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada;
| | - Vitor Hugo B. Serrão
- Biomolecular Cryo-Electron Microscopy Facility, University of California-Santa Cruz, Santa Cruz, CA 95064, USA;
- Department of Chemistry and Biochemistry, University of California-Santa Cruz, Santa Cruz, CA 95064, USA
| |
Collapse
|
4
|
Feix AS, Cruz-Bustos T, Ruttkowski B, Joachim A. Inhibition of sexual stage-specific proteins results in reduced numbers of sexual stages and oocysts of Cystoisospora suis (Apicomplexa: Coccidia) in vitro. Int J Parasitol 2022; 52:829-841. [PMID: 36270547 DOI: 10.1016/j.ijpara.2022.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/30/2022] [Accepted: 09/01/2022] [Indexed: 11/05/2022]
Abstract
Parasites of the order Coccidia (phylum: Alveolata, subphylum: Apicomplexa) have sophisticated life cycles that include a switch from asexual to sexual development, characterised by distinct cell types. During the development of gametes (gamogony), substantial changes occur at the cellular and subcellular levels, leading to cell fusion of micro- and microgametes, and the development of a zygote that forms a protective outer layer for environmental survival as an oocyst, the transmissible stage. Studies on the porcine coccidian Cystoisospora suis already identified changes in transcription profiles during different time points in the parasite's development and identified proteins with potential roles in the sexual development of this parasite. Here, we focus on three proteins that are possibly involved in the sexual development of C. suis. Enkurin and hapless protein 2 (HAP2) play important roles in signal transduction and gamete fusion during the fertilisation process, and oocyst wall forming protein 1 (OWP1) is a homologue of oocyst wall forming proteins of related parasites. We evaluated their locations in the different life cycle stages of C. suis and their inhibition by specific antibodies in vitro. Immunolocalization detected enkurin in merozoites and sporulated oocysts, HAP2 in merozoites and microgamonts, and OWP2 in merozoites, macrogamonts, oocysts and sporozoites. Up to 100% inhibition of the development of sexual stages and oocyst formation with purified chicken immunoglobulin IgY sera against recombinant enkurin, HAP2, and especially OWP1, were demonstrated. We conclude that the three investigated sexual stage-specific proteins constitute targets for in vivo intervention strategies to interrupt parasite development and transmission to susceptible hosts.
Collapse
Affiliation(s)
- Anna Sophia Feix
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, Vienna A-1210, Austria.
| | - Teresa Cruz-Bustos
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, Vienna A-1210, Austria
| | - Bärbel Ruttkowski
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, Vienna A-1210, Austria
| | - Anja Joachim
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, Vienna A-1210, Austria
| |
Collapse
|
5
|
Snell WJ. Uncovering an ancestral green ménage à trois: Contributions of Chlamydomonas to the discovery of a broadly conserved triad of plant fertilization proteins. CURRENT OPINION IN PLANT BIOLOGY 2022; 69:102275. [PMID: 36007296 PMCID: PMC9899528 DOI: 10.1016/j.pbi.2022.102275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 06/22/2022] [Accepted: 07/04/2022] [Indexed: 05/10/2023]
Abstract
During sexual reproduction in the unicellular green alga Chlamydomonas, gametes undergo the conserved cellular events that define fertilization across the tree of life. After initial ciliary adhesion, plus and minus gametes attach to each other at plasma membrane sites specialized for fusion, their bilayers merge, and cell coalescence into a quadri-ciliated cell signals for nuclear fusion. Recent findings show that these conserved cellular events are driven by 3 conserved protein families, FUS1/GEX2, HAP2/GCS1, and KAR5/GEX1. New results also show that species-specific recognition in Chlamydomonas activates the ancestral, viral-like fusogen HAP2 to drive fusion; that the conserved nuclear envelope fusion protein KAR5/GEX1 is also essential for nuclear fusion in Arabidopsis; and that heterodimerization of BELL-KNOX proteins signals for nuclear fusion in Chlamydomonas through early diverging land plants. This review outlines how Chlamydomonas's Janus-like position in evolution along with the ease of working with its gametes have revealed broadly conserved mechanisms.
Collapse
Affiliation(s)
- William J Snell
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA.
| |
Collapse
|
6
|
Feng J, Dong X, Su Y, Lu C, Springer TA. Monomeric prefusion structure of an extremophile gamete fusogen and stepwise formation of the postfusion trimeric state. Nat Commun 2022; 13:4064. [PMID: 35831325 PMCID: PMC9279424 DOI: 10.1038/s41467-022-31744-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 06/30/2022] [Indexed: 11/30/2022] Open
Abstract
Here, we study the gamete fusogen HAP2 from Cyanidioschyzon merolae (Cyani), an extremophile red algae that grows at acidic pH at 45 °C. HAP2 has a trimeric postfusion structure with similarity to viral class II fusion proteins, but its prefusion structure has been elusive. The crystal structure of a monomeric prefusion state of Cyani HAP2 shows it is highly extended with three domains in the order D2, D1, and D3. Three hydrophobic fusion loops at the tip of D2 are each required for postfusion state formation. We followed by negative stain electron microscopy steps in the process of detergent micelle-stimulated postfusion state formation. In an intermediate state, two or three linear HAP2 monomers associate at the end of D2 bearing its fusion loops. Subsequently, D2 and D1 line the core of a trimer and D3 folds back over the exterior of D1 and D2. D3 is not required for formation of intermediate or postfusion-like states.
Collapse
Affiliation(s)
- Juan Feng
- Program in Cellular and Molecular Medicine, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology and Harvard Medical School, Boston, MA, USA
| | - Xianchi Dong
- Program in Cellular and Molecular Medicine, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology and Harvard Medical School, Boston, MA, USA
- School of Life Sciences, Nanjing University, Nanjing, China
| | - Yang Su
- Program in Cellular and Molecular Medicine, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology and Harvard Medical School, Boston, MA, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Chafen Lu
- Program in Cellular and Molecular Medicine, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology and Harvard Medical School, Boston, MA, USA
| | - Timothy A Springer
- Program in Cellular and Molecular Medicine, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA.
- Department of Biological Chemistry and Molecular Pharmacology and Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
7
|
Yu S, Wang J, Luo X, Zheng H, Wang L, Yang X, Wang Y. Transmission-Blocking Strategies Against Malaria Parasites During Their Mosquito Stages. Front Cell Infect Microbiol 2022; 12:820650. [PMID: 35252033 PMCID: PMC8889032 DOI: 10.3389/fcimb.2022.820650] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 01/31/2022] [Indexed: 11/24/2022] Open
Abstract
Malaria is still the most widespread parasitic disease and causes the most infections globally. Owing to improvements in sanitary conditions and various intervention measures, including the use of antimalarial drugs, the malaria epidemic in many regions of the world has improved significantly in the past 10 years. However, people living in certain underdeveloped areas are still under threat. Even in some well-controlled areas, the decline in malaria infection rates has stagnated or the rates have rebounded because of the emergence and spread of drug-resistant malaria parasites. Thus, new malaria control methods must be developed. As the spread of the Plasmodium parasite is dependent on the part of its life cycle that occurs in mosquitoes, to eliminate the possibility of malaria infections, transmission-blocking strategies against the mosquito stage should be the first choice. In fact, after the gametocyte enters the mosquito body, it undergoes a series of transformation processes over a short period, thus providing numerous potential blocking targets. Many research groups have carried out studies based on targeting the blocking of transmission during the mosquito phase and have achieved excellent results. Meanwhile, the direct killing of mosquitoes could also significantly reduce the probability of malaria infections. Microorganisms that display complex interactions with Plasmodium, such as Wolbachia and gut flora, have shown observable transmission-blocking potential. These could be used as a biological control strategy and play an important part in blocking the transmission of malaria.
Collapse
Affiliation(s)
- Shasha Yu
- Department of Tropical Medicine, College of Military Preventive Medicine, Army Medical University, Chongqing, China
| | - Jing Wang
- Department of Tropical Medicine, College of Military Preventive Medicine, Army Medical University, Chongqing, China
| | - Xue Luo
- Department of Tropical Medicine, College of Military Preventive Medicine, Army Medical University, Chongqing, China
| | - Hong Zheng
- Department of Thoracic Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Luhan Wang
- Department of Tropical Medicine, College of Military Preventive Medicine, Army Medical University, Chongqing, China
| | - Xuesen Yang
- Department of Tropical Medicine, College of Military Preventive Medicine, Army Medical University, Chongqing, China
| | - Ying Wang
- Department of Tropical Medicine, College of Military Preventive Medicine, Army Medical University, Chongqing, China
- *Correspondence: Ying Wang,
| |
Collapse
|