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Liffner B, Absalon S. Expansion microscopy of apicomplexan parasites. Mol Microbiol 2024; 121:619-635. [PMID: 37571814 DOI: 10.1111/mmi.15135] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 07/15/2023] [Accepted: 07/20/2023] [Indexed: 08/13/2023]
Abstract
Apicomplexan parasites comprise significant pathogens of humans, livestock and wildlife, but also represent a diverse group of eukaryotes with interesting and unique cell biology. The study of cell biology in apicomplexan parasites is complicated by their small size, and historically this has required the application of cutting-edge microscopy techniques to investigate fundamental processes like mitosis or cell division in these organisms. Recently, a technique called expansion microscopy has been developed, which rather than increasing instrument resolution like most imaging modalities, physically expands a biological sample. In only a few years since its development, a derivative of expansion microscopy known as ultrastructure-expansion microscopy (U-ExM) has been widely adopted and proven extremely useful for studying cell biology of Apicomplexa. Here, we review the insights into apicomplexan cell biology that have been enabled through the use of U-ExM, with a specific focus on Plasmodium, Toxoplasma and Cryptosporidium. Further, we summarize emerging expansion microscopy modifications and modalities and forecast how these may influence the field of parasite cell biology in future.
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Affiliation(s)
- Benjamin Liffner
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Sabrina Absalon
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Padilla LFA, Murray JM, Hu K. The initiation and early development of the tubulin-containing cytoskeleton in the human parasite Toxoplasma gondii. Mol Biol Cell 2024; 35:ar37. [PMID: 38170577 PMCID: PMC10916856 DOI: 10.1091/mbc.e23-11-0418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/11/2023] [Accepted: 12/19/2023] [Indexed: 01/05/2024] Open
Abstract
The tubulin-containing cytoskeleton of the human parasite Toxoplasma gondii includes several distinct structures: the conoid, formed of 14 ribbon-like tubulin polymers, and the array of 22 cortical microtubules (MTs) rooted in the apical polar ring. Here we analyze the structure of developing daughter parasites using both 3D-SIM and expansion microscopy. Cortical MTs and the conoid start to develop almost simultaneously, but from distinct precursors near the centrioles. Cortical MTs are initiated in a fixed sequence, starting around the periphery of a short arc that extends to become a complete circle. The conoid also develops from an open arc into a full circle, with a fixed spatial relationship to the centrioles. The patterning of the MT array starts from a "blueprint" with ∼five-fold symmetry, switching to 22-fold rotational symmetry in the final product, revealing a major structural rearrangement during daughter growth. The number of MT is essentially invariant in the wild-type array, but is perturbed by the loss of some structural components of the apical polar ring. This study provides insights into the development of tubulin-containing structures that diverge from conventional models, insights that are critical for understanding the evolutionary paths leading to construction and divergence of cytoskeletal frameworks.
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Affiliation(s)
- Luisa F. Arias Padilla
- Biodesign Center for Mechanisms of Evolution/School of Life Sciences, Arizona State University
| | - John M. Murray
- Biodesign Center for Mechanisms of Evolution/School of Life Sciences, Arizona State University
| | - Ke Hu
- Biodesign Center for Mechanisms of Evolution/School of Life Sciences, Arizona State University
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Liffner B, Cepeda Diaz AK, Blauwkamp J, Anaguano D, Frolich S, Muralidharan V, Wilson DW, Dvorin JD, Absalon S. Atlas of Plasmodium falciparum intraerythrocytic development using expansion microscopy. eLife 2023; 12:RP88088. [PMID: 38108809 PMCID: PMC10727503 DOI: 10.7554/elife.88088] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023] Open
Abstract
Apicomplexan parasites exhibit tremendous diversity in much of their fundamental cell biology, but study of these organisms using light microscopy is often hindered by their small size. Ultrastructural expansion microscopy (U-ExM) is a microscopy preparation method that physically expands the sample by ~4.5×. Here, we apply U-ExM to the human malaria parasite Plasmodium falciparum during the asexual blood stage of its lifecycle to understand how this parasite is organized in three dimensions. Using a combination of dye-conjugated reagents and immunostaining, we have cataloged 13 different P. falciparum structures or organelles across the intraerythrocytic development of this parasite and made multiple observations about fundamental parasite cell biology. We describe that the outer centriolar plaque and its associated proteins anchor the nucleus to the parasite plasma membrane during mitosis. Furthermore, the rhoptries, Golgi, basal complex, and inner membrane complex, which form around this anchoring site while nuclei are still dividing, are concurrently segregated and maintain an association to the outer centriolar plaque until the start of segmentation. We also show that the mitochondrion and apicoplast undergo sequential fission events while maintaining an association with the outer centriolar plaque during cytokinesis. Collectively, this study represents the most detailed ultrastructural analysis of P. falciparum during its intraerythrocytic development to date and sheds light on multiple poorly understood aspects of its organelle biogenesis and fundamental cell biology.
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Affiliation(s)
- Benjamin Liffner
- Department of Pharmacology and Toxicology, Indiana University School of MedicineIndianapolisUnited States
| | - Ana Karla Cepeda Diaz
- Biological and Biomedical Sciences, Harvard Medical SchoolBostonUnited States
- Division of Infectious Diseases, Boston Children’s HospitalBostonUnited States
| | - James Blauwkamp
- Department of Pharmacology and Toxicology, Indiana University School of MedicineIndianapolisUnited States
| | - David Anaguano
- Center for Tropical and Emerging Global Diseases, University of GeorgiaAthensUnited States
- Department of Cellular Biology, Franklin College of Arts and Sciences, University of GeorgiaAthensUnited States
| | - Sonja Frolich
- Research Centre for Infectious Diseases, School of Biological Sciences, University of AdelaideAdelaideAustralia
- Institute for Photonics and Advanced Sensing, University of AdelaideAdelaideAustralia
| | - Vasant Muralidharan
- Center for Tropical and Emerging Global Diseases, University of GeorgiaAthensUnited States
- Department of Cellular Biology, Franklin College of Arts and Sciences, University of GeorgiaAthensUnited States
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, University of AdelaideAdelaideAustralia
- Institute for Photonics and Advanced Sensing, University of AdelaideAdelaideAustralia
- Burnet Institute, 85 Commercial RoadMelbourneAustralia
| | - Jeffrey D Dvorin
- Division of Infectious Diseases, Boston Children’s HospitalBostonUnited States
- Department of Pediatrics, Harvard Medical SchoolBostonUnited States
| | - Sabrina Absalon
- Department of Pharmacology and Toxicology, Indiana University School of MedicineIndianapolisUnited States
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Arias Padilla LF, Murray JM, Hu K. The initiation and early development of the tubulin-containing cytoskeleton in the human parasite Toxoplasma gondii. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.03.565597. [PMID: 38106158 PMCID: PMC10723254 DOI: 10.1101/2023.11.03.565597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
The tubulin-containing cytoskeleton of the human parasite Toxoplasma gondii includes several distinct structures: the conoid, formed of 14 ribbon-like tubulin polymers, and the array of 22 cortical microtubules (MTs) rooted in the apical polar ring. Here we analyze the structure of developing daughter parasites using both 3D-SIM and expansion microscopy. Cortical MTs and the conoid start to develop almost simultaneously, but from distinct precursors near the centrioles. Cortical MTs are initiated in a fixed sequence, starting around the periphery of a short arc that extends to become a complete circle. The conoid also develops from an open arc into a full circle, with a fixed spatial relationship to the centrioles. The patterning of the MT array starts from a "blueprint" with ∼ 5-fold symmetry, switching to 22-fold rotational symmetry in the final product, revealing a major structural rearrangement during daughter growth. The number of MT is essentially invariant in the wild-type array, but is perturbed by the loss of some structural components of the apical polar ring. This study provides insights into the development of tubulin-containing structures that diverge from conventional models, insights that are critical for understanding the evolutionary paths leading to construction and divergence of cytoskeletal frameworks.
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Singer M, Frischknecht F. Still running fast: Plasmodium ookinetes and sporozoites 125 years after their discovery. Trends Parasitol 2023; 39:991-995. [PMID: 37865610 DOI: 10.1016/j.pt.2023.09.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/21/2023] [Accepted: 09/25/2023] [Indexed: 10/23/2023]
Abstract
Plasmodium ookinetes and sporozoites were discovered 125 years ago by MacCallum (J. Exp. Med. 1898;3:117-136) and Ross (Ind. Med. Gaz. 1899;34:1-3), respectively. While the migration capacity of ookinetes was noted immediately, the movements of sporozoites remained enigmatic for decades. Today, we know many proteins involved in parasite migration and start to conceptualize a mechanistic understanding of motility.
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Affiliation(s)
- Mirko Singer
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, 69120 Heidelberg, Germany.
| | - Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, 69120 Heidelberg, Germany; German Center for Infection Research, TTU Malaria and Neglected Tropical Diseases, partner site Heidelberg, Heidelberg, Germany.
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Liffner B, Cepeda Diaz AK, Blauwkamp J, Anaguano D, Frölich S, Muralidharan V, Wilson DW, Dvorin J, Absalon S. Atlas of Plasmodium falciparum intraerythrocytic development using expansion microscopy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.22.533773. [PMID: 36993606 PMCID: PMC10055389 DOI: 10.1101/2023.03.22.533773] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Apicomplexan parasites exhibit tremendous diversity in much of their fundamental cell biology, but study of these organisms using light microscopy is often hindered by their small size. Ultrastructural expansion microscopy (U-ExM) is a microscopy preparation method that physically expands the sample ~4.5x. Here, we apply U-ExM to the human malaria parasite Plasmodium falciparum during the asexual blood stage of its lifecycle to understand how this parasite is organized in three-dimensions. Using a combination of dye-conjugated reagents and immunostaining, we have catalogued 13 different P. falciparum structures or organelles across the intraerythrocytic development of this parasite and made multiple observations about fundamental parasite cell biology. We describe that the outer centriolar plaque and its associated proteins anchor the nucleus to the parasite plasma membrane during mitosis. Furthermore, the rhoptries, Golgi, basal complex, and inner membrane complex, which form around this anchoring site while nuclei are still dividing, are concurrently segregated and maintain an association to the outer centriolar plaque until the start of segmentation. We also show that the mitochondrion and apicoplast undergo sequential fission events while maintaining an association with the outer centriolar plaque during cytokinesis. Collectively, this study represents the most detailed ultrastructural analysis of P. falciparum during its intraerythrocytic development to date, and sheds light on multiple poorly understood aspects of its organelle biogenesis and fundamental cell biology.
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Affiliation(s)
- Benjamin Liffner
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Ana Karla Cepeda Diaz
- Biological and Biomedical Sciences, Harvard Medical School, Boston MA, USA
- Division of Infectious Diseases, Boston Children’s Hospital, Boston MA, USA
| | - James Blauwkamp
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - David Anaguano
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
- Department of Cellular Biology, Franklin College of Arts and Sciences, University of Georgia, Athens, GA, USA
| | - Sonja Frölich
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Vasant Muralidharan
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
- Department of Cellular Biology, Franklin College of Arts and Sciences, University of Georgia, Athens, GA, USA
| | - Danny W. Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
- Institute for Photonics and Advanced Sensing, University of Adelaide, Adelaide, SA, Australia
- Burnet Institute, 85 Commercial Road, Melbourne, VIC, Australia
| | - Jeffrey Dvorin
- Division of Infectious Diseases, Boston Children’s Hospital, Boston MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Sabrina Absalon
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, USA
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Russell AC, Bush P, Grigorean G, Kyle DE. Characterization of the extracellular vesicles, ultrastructural morphology, and intercellular interactions of multiple clinical isolates of the brain-eating amoeba, Naegleria fowleri. Front Microbiol 2023; 14:1264348. [PMID: 37808283 PMCID: PMC10558758 DOI: 10.3389/fmicb.2023.1264348] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 09/08/2023] [Indexed: 10/10/2023] Open
Abstract
Introduction As global temperatures rise to unprecedented historic levels, so too do the latitudes of habitable niches for the pathogenic free-living amoeba, Naegleria fowleri. This opportunistic parasite causes a rare, but >97% fatal, neurological infection called primary amoebic meningoencephalitis. Despite its lethality, this parasite remains one of the most neglected and understudied parasitic protozoans. Methods To better understand amoeboid intercellular communication, we elucidate the structure, proteome, and potential secretion mechanisms of amoeba-derived extracellular vesicles (EVs), which are membrane-bound communication apparatuses that relay messages and can be used as biomarkers for diagnostics in various diseases. Results and Discussion Herein we propose that N. fowleri secretes EVs in clusters from the plasma membrane, from multivesicular bodies, and via beading of thin filaments extruding from the membrane. Uptake assays demonstrate that EVs are taken up by other amoebae and mammalian cells, and we observed a real-time increase in metabolic activity for mammalian cells exposed to EVs from amoebae. Proteomic analysis revealed >2,000 proteins within the N. fowleri-secreted EVs, providing targets for the development of diagnostics or therapeutics. Our work expands the knowledge of intercellular interactions among these amoebae and subsequently deepens the understanding of the mechanistic basis of PAM.
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Affiliation(s)
- A. Cassiopeia Russell
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
- Department of Infectious Diseases, University of Georgia, Athens, GA, United States
| | - Peter Bush
- School of Dental Medicine, University at Buffalo, Buffalo, NY, United States
| | - Gabriela Grigorean
- Proteomics Core Facility, University of California, Davis, Davis, CA, United States
| | - Dennis E. Kyle
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
- Department of Infectious Diseases, University of Georgia, Athens, GA, United States
- Department of Cellular Biology, University of Georgia, Athens, GA, United States
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