1
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Kimball A, Funkhouser-Jones L, Huang W, Xu R, Witola WH, Sibley LD. Mendelian segregation and high recombination rates facilitate genetic analyses in Cryptosporidium parvum. bioRxiv 2024:2024.02.02.578536. [PMID: 38352509 PMCID: PMC10862819 DOI: 10.1101/2024.02.02.578536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Very little is known about the process of meiosis in the apicomplexan parasite Cryptosporidium despite the essentiality of sex in its life cycle. Most cell lines only support asexual growth of Cryptosporidium parvum (C. parvum), but stem cell derived intestinal epithelial cells grown under air-liquid interface (ALI) conditions support the sexual cycle. To examine chromosomal dynamics during meiosis in C. parvum, we generated two transgenic lines of parasites that were fluorescently tagged with mCherry or GFP on chromosomes 1 or 5, respectively. Infection of ALI cultures or Ifngr1-/- mice with mCherry and GFP parasites produced "yellow" oocysts generated by cross-fertilization. Outcrossed oocysts from the F1 generation were purified and used to infect HCT-8 cultures, and phenotypes of the progeny were observed by microscopy. All possible phenotypes predicted by independent segregation were represented equally (~25%) in the population, indicating that C. parvum chromosomes exhibit a Mendelian inheritance pattern. Unexpectedly, the most common pattern observed from the outgrowth of single oocysts included all possible parental and recombinant phenotypes derived from a single meiotic event, suggesting a high rate of crossover. To estimate the frequency of crossover, additional loci on chromosomes 1 and 5 were tagged and used to monitor intrachromosomal crosses in Ifngr1-/- mice. Both chromosomes showed a high frequency of crossover compared to other apicomplexans with map distances (i.e., 1% recombination) of 3-12 kb. Overall, a high recombination rate may explain many unique characteristics observed in Cryptosporidium spp. such as high rates of speciation, wide variation in host range, and rapid evolution of host-specific virulence factors.
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Affiliation(s)
- Abigail Kimball
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Lisa Funkhouser-Jones
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Wanyi Huang
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Rui Xu
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - William H. Witola
- Department of Pathobiology, University of Illinois Urbana-Champaign College of Veterinary Medicine, Urbana, IL 61802, USA
| | - L. David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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2
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Xu R, Beatty WL, Greigert V, Witola WH, Sibley LD. Multiple pathways for glucose phosphate transport and utilization support growth of Cryptosporidium parvum. Nat Commun 2024; 15:380. [PMID: 38191884 PMCID: PMC10774378 DOI: 10.1038/s41467-024-44696-3] [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] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 12/21/2023] [Indexed: 01/10/2024] Open
Abstract
Cryptosporidium parvum is an obligate intracellular parasite with a highly reduced mitochondrion that lacks the tricarboxylic acid cycle and the ability to generate ATP, making the parasite reliant on glycolysis. Genetic ablation experiments demonstrated that neither of the two putative glucose transporters CpGT1 and CpGT2 were essential for growth. Surprisingly, hexokinase was also dispensable for parasite growth while the downstream enzyme aldolase was required, suggesting the parasite has an alternative way of obtaining phosphorylated hexose. Complementation studies in E. coli support a role for direct transport of glucose-6-phosphate from the host cell by the parasite transporters CpGT1 and CpGT2, thus bypassing a requirement for hexokinase. Additionally, the parasite obtains phosphorylated glucose from amylopectin stores that are released by the action of the essential enzyme glycogen phosphorylase. Collectively, these findings reveal that C. parvum relies on multiple pathways to obtain phosphorylated glucose both for glycolysis and to restore carbohydrate reserves.
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Affiliation(s)
- Rui Xu
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63130, USA
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China
| | - Wandy L Beatty
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63130, USA
| | - Valentin Greigert
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63130, USA
| | - William H Witola
- Department of Pathobiology, University of Illinois Urbana-Champaign, Urbana, IL, 61802, USA
| | - L David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63130, USA.
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3
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Greigert V, Saraav I, Son J, Zhu Y, Dayao D, Antia A, Tzipori S, Witola WH, Stappenbeck TS, Ding S, Sibley LD. Cryptosporidium infection of human small intestinal epithelial cells induces type III interferon and impairs infectivity of Rotavirus. Gut Microbes 2024; 16:2297897. [PMID: 38189373 PMCID: PMC10793699 DOI: 10.1080/19490976.2023.2297897] [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: 10/11/2023] [Accepted: 12/18/2023] [Indexed: 01/09/2024] Open
Abstract
Cryptosporidiosis is a major cause of severe diarrheal disease in infants from resource poor settings. The majority of infections are caused by the human-specific pathogen C. hominis and absence of in vitro growth platforms has limited our understanding of host-pathogen interactions and development of effective treatments. To address this problem, we developed a stem cell-derived culture system for C. hominis using human enterocytes differentiated under air-liquid interface (ALI) conditions. Human ALI cultures supported robust growth and complete development of C. hominis in vitro including all life cycle stages. Cryptosporidium infection induced a strong interferon response from enterocytes, possibly driven, in part, by an endogenous dsRNA virus in the parasite. Prior infection with Cryptosporidium induced type III IFN secretion and consequently blunted infection with Rotavirus, including live attenuated vaccine strains. The development of hALI provides a platform for further studies on human-specific pathogens, including clinically important coinfections that may alter vaccine efficacy.
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Affiliation(s)
- Valentin Greigert
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Iti Saraav
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Juhee Son
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Yinxing Zhu
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Denise Dayao
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA, USA
| | - Avan Antia
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Saul Tzipori
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA, USA
| | - William H. Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Thaddeus S. Stappenbeck
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Siyuan Ding
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - L. David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
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4
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Khan SM, Bajwa MR, Lahar RY, Witola WH. Combination of inhibitors for two glycolytic enzymes portrays high synergistic efficacy against Cryptosporidium parvum. Antimicrob Agents Chemother 2023; 67:e0056923. [PMID: 37655889 PMCID: PMC10583678 DOI: 10.1128/aac.00569-23] [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] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 06/22/2023] [Indexed: 09/02/2023] Open
Abstract
Cryptosporidium is an intracellular protozoan parasite that causes serious enteric disease in humans and in a wide range of animals worldwide. Despite its high prevalence, no effective therapeutic drugs are available against life-threatening cryptosporidiosis in at-risk populations including malnourished children, immunocompromised patients, and neonatal calves. Thus, new efficacious drugs are urgently needed to treat all susceptible populations with cryptosporidiosis. Unlike other apicomplexans, Cryptosporidium parvum lacks the tricarboxylic acid cycle and the oxidative phosphorylation steps, making it solely dependent on glycolysis for metabolic energy production. We have previously reported that individual inhibitors of two unique glycolytic enzymes, the plant-like pyruvate kinase (CpPyK) and the bacterial-type lactate dehydrogenase (CpLDH), are effective against C. parvum, both in vitro and in vivo. Herein, we have derived combinations of CpPyK and CpLDH inhibitors with strong synergistic effects against the growth and survival of C. parvum, both in vitro and in an infection mouse model. In infected immunocompromised mice, compound combinations of NSC303244 + NSC158011 and NSC252172 + NSC158011 depicted enhanced efficacy against C. parvum reproduction and ameliorated intestinal lesions of cryptosporidiosis at doses fourfold lower than the total effective doses of individual compounds. Importantly, unlike individual compounds, NSC303244 + NSC158011 combination was effective in clearing the infection completely without relapse in immunocompromised mice. Collectively, our study has unveiled compound combinations that simultaneously block two essential catalytic steps for metabolic energy production in C. parvum to achieve improved efficacy against the parasite. These combinations are, therefore, lead compounds for the development of a new generation of efficacious anti-cryptosporidial drugs.
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Affiliation(s)
- Shahbaz M. Khan
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Muhammad Rashid Bajwa
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Rachael Y. Lahar
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - William H. Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
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Greigert V, Saraav I, Son J, Dayao D, Antia A, Tzipori S, Witola WH, Stappenbeck TS, Ding S, Sibley LD. Cryptosporidium infection of human small intestinal epithelial cells induces type III interferon and impairs infectivity of Rotavirus. bioRxiv 2023:2023.08.30.555581. [PMID: 37693422 PMCID: PMC10491271 DOI: 10.1101/2023.08.30.555581] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Cryptosporidiosis is a major cause of severe diarrheal disease in infants from resource poor settings. The majority of infections are caused by the human-specific pathogen C. hominis and absence of in vitro growth platforms has limited our understanding of host-pathogen interactions and development of effective treatments. To address this problem, we developed a stem cell-derived culture system for C. hominis using human enterocytes differentiated under air-liquid interface (ALI) conditions. Human ALI cultures supported robust growth and complete development of C. hominis in vitro including all life cycle stages. C. hominis infection induced a strong interferon response from enterocytes, likely driven by an endogenous dsRNA virus in the parasite. Prior infection with Cryptosporidium induced type III IFN secretion and consequently blunted infection with Rotavirus, including live attenuated vaccine strains. The development of hALI provides a platform for further studies on human-specific pathogens, including clinically important coinfections that may alter vaccine efficacy.
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Affiliation(s)
- Valentin Greigert
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Iti Saraav
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Juhee Son
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Denise Dayao
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA, 01536, USA
| | - Avan Antia
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Saul Tzipori
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA, 01536, USA
| | - William H. Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, 61802, USA
| | - Thaddeus S. Stappenbeck
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Siyuan Ding
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - L. David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, 63110, USA
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Xu R, Beatty WL, Greigert V, Witola WH, Sibley LD. Multiple pathways for glucose phosphate transport and utilization support growth of Cryptosporidium parvum. bioRxiv 2023:2023.06.27.546703. [PMID: 37425855 PMCID: PMC10327089 DOI: 10.1101/2023.06.27.546703] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Cryptosporidium parvum is an obligate intracellular parasite with a highly reduced mitochondrion that lacks the TCA cycle and the ability to generate ATP, making the parasite reliant on glycolysis. Genetic ablation experiments demonstrated that neither of the two putative glucose transporters CpGT1 and CpGT2 were essential for growth. Surprisingly, hexokinase was also dispensable for parasite growth while the downstream enzyme aldolase was required, suggesting the parasite has an alternative way of obtaining phosphorylated hexose. Complementation studies in E. coli support a role for direct transport of glucose-6-phosphate from the host cell by the parasite transporters CpGT1 and CpGT2, thus bypassing a requirement for hexokinase. Additionally, the parasite obtains phosphorylated glucose from amylopectin stores that are released by the action of the essential enzyme glycogen phosphorylase. Collectively, these findings reveal that C. parvum relies on multiple pathways to obtain phosphorylated glucose both for glycolysis and to restore carbohydrate reserves.
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Affiliation(s)
- Rui Xu
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63130, USA
| | - Wandy L. Beatty
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63130, USA
| | - Valentin Greigert
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63130, USA
| | - William H. Witola
- Department of Pathobiology, University of Illinois Urbana-Champaign, Urbana, IL 61802, USA
| | - L. David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63130, USA
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7
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Zhang X, Sicalo Gianechini L, Li K, Kaplan RM, Witola WH. Broad-Spectrum Inhibitors for Conserved Unique Phosphoethanolamine Methyltransferases in Parasitic Nematodes Possess Anthelmintic Efficacy. Antimicrob Agents Chemother 2023; 67:e0000823. [PMID: 37212658 PMCID: PMC10269165 DOI: 10.1128/aac.00008-23] [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] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 04/20/2023] [Indexed: 05/23/2023] Open
Abstract
In humans, nematode infections are prevalent in developing countries, causing long-term ill health, particularly in children. Worldwide, nematode infections are prevalent in livestock and pets, affecting productivity and health. Anthelmintic drugs are the primary means of controlling nematodes, but there is now high prevalence of anthelmintic resistance, requiring urgent identification of new molecular targets for anthelmintics with novel mechanisms of action. Here, we identified orthologous genes for phosphoethanolamine methyltransferases (PMTs) in nematodes within the families Trichostrongylidae, Dictyocaulidae, Chabertiidae, Ancylostomatoidea, and Ascarididae. We characterized these putative PMTs and found that they possess bona fide PMT catalytic activities. By complementing a mutant yeast strain lacking the ability to synthesize phosphatidylcholine, the PMTs were validated to catalyze the biosynthesis of phosphatidylcholine. Using an in vitro phosphoethanolamine methyltransferase assay with PMTs as enzymes, we identified compounds with cross-inhibitory effects against the PMTs. Corroboratively, treatment of PMT-complemented yeast with the PMT inhibitors blocked growth of the yeast, underscoring the essential role of the PMTs in phosphatidylcholine synthesis. Fifteen of the inhibitors with the highest activity against complemented yeast were tested against Haemonchus contortus using larval development and motility assays. Among them, four were found to possess potent anthelmintic activity against both multiple drug-resistant and susceptible isolates of H. contortus, with IC50 values (95% confidence interval) of 4.30 μM (2.15-8.28), 4.46 μM (3.22-6.16), 28.7 μM (17.3-49.5), and 0.65 μM (0.21-1.88). Taken together, we have validated a molecular target conserved in a broad range of nematodes and identified its inhibitors that possess potent in vitro anthelmintic activity.
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Affiliation(s)
- Xuejin Zhang
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | | | - Kun Li
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Institute of Traditional Chinese Veterinary Medicine, MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Ray M. Kaplan
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
- Pathobiology Department, School of Veterinary Medicine, St. George’s University, Grenada, West Indies
| | - William H. Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
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Khan SM, Witola WH. Past, current, and potential treatments for cryptosporidiosis in humans and farm animals: A comprehensive review. Front Cell Infect Microbiol 2023; 13:1115522. [PMID: 36761902 PMCID: PMC9902888 DOI: 10.3389/fcimb.2023.1115522] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 01/09/2023] [Indexed: 01/25/2023] Open
Abstract
The intracellular protozoan parasite of the genus Cryptosporidium is among the leading causes of waterborne diarrheal disease outbreaks throughout the world. The parasite is transmitted by ingestion of infective oocysts that are highly stable in the environment and resistant to almost all conventional disinfection methods and water treatments. Control of the parasite infection is exceedingly difficult due to the excretion of large numbers of oocysts in the feces of infected individuals that contaminate the environment and serve as a source of infection for susceptible hosts including humans and animals. Drug development against the parasite is challenging owing to its limited genetic tractability, absence of conventional drug targets, unique intracellular location within the host, and the paucity of robust cell culture platforms for continuous parasite propagation. Despite the high prevalence of the parasite, the only US Food and Drug Administration (FDA)-approved treatment of Cryptosporidium infections is nitazoxanide, which has shown moderate efficacy in immunocompetent patients. More importantly, no effective therapeutic drugs are available for treating severe, potentially life-threatening cryptosporidiosis in immunodeficient patients, young children, and neonatal livestock. Thus, safe, inexpensive, and efficacious drugs are urgently required to reduce the ever-increasing global cryptosporidiosis burden especially in low-resource countries. Several compounds have been tested for both in vitro and in vivo efficacy against the disease. However, to date, only a few experimental compounds have been subjected to clinical trials in natural hosts, and among those none have proven efficacious. This review provides an overview of the past and present anti-Cryptosporidium pharmacotherapy in humans and agricultural animals. Herein, we also highlight the progress made in the field over the last few years and discuss the different strategies employed for discovery and development of effective prospective treatments for cryptosporidiosis.
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Zhang X, Meadows SN, Martin T, Doran A, Angles R, Sander S, Bronson E, Witola WH. Plasmodium relictum MSP-1 capture antigen-based ELISA for detection of avian malaria antibodies in African penguins (Spheniscus demersus). Int J Parasitol Parasites Wildl 2022; 19:89-95. [PMID: 36090665 PMCID: PMC9459682 DOI: 10.1016/j.ijppaw.2022.08.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/19/2022] [Accepted: 08/19/2022] [Indexed: 11/30/2022]
Abstract
Avian malaria, caused by Plasmodium spp. and transmitted by mosquitos, is a leading cause of mortality of captive penguins. Antimalarial drugs are currently used to control infections in penguins. However, the effectiveness of treatment reduces significantly by the time the clinical signs appear, while early and unnecessary treatment interferes with development of protective immunity. Therefore, for suppressing parasitemia without affecting the development of immunity in captive penguins, antimalaria drugs need to be administered at the right time, which requires reliable diagnostic tools that can determine the levels of circulating antimalaria antibodies. In the present study, we have developed an enzyme-linked immunosorbent assay (ELISA) diagnostic assay based on the merozoite surface protein 1 (MSP-1) of P. relictum isolate SGS1 to specifically detect and relatively quantify antimalaria antibodies in penguins. We expressed and purified a truncated P. relictum isolate SGS1 MSP-1 and optimized its biotinylation and subsequent conjugation to streptavidin alkaline phosphatase for signal generation in ELISA. We tested the assay by analyzing sera obtained from penguins at the Baltimore Zoo, from Spring through Fall, and found that levels of detectable antibodies against MSP-1 varied seasonally for individual penguins, consistent with the expected seasonal variations in avian malaria prevalence. Corroboratively, we analyzed the sensitivity of the assay by titrating positive sera and found that the signal intensity generated was serum concentration-dependent, thus validating the ability of the assay to detect and relatively quantify the levels of antimalaria antibodies in penguin sera. ELISA based on MSP1 for detection and quantification of antibodies against Plasmodium relictum in birds was developed. Assay was validated to detect and quantify levels of antimalaria antibodies in infected penguins' sera. Assay detected varied antibody levels against MSP-1 in penguin sera consistent with seasonal variations in malaria prevalence.
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Khan SM, Zhang X, Witola WH. Cryptosporidium parvum Pyruvate Kinase Inhibitors With in vivo Anti-cryptosporidial Efficacy. Front Microbiol 2022; 12:800293. [PMID: 35046922 PMCID: PMC8761912 DOI: 10.3389/fmicb.2021.800293] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [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: 10/22/2021] [Accepted: 12/09/2021] [Indexed: 11/13/2022] Open
Abstract
Cryptosporidium parvum is a highly prevalent protozoan parasite that causes a diarrheal disease in humans and animals worldwide. Thus far, the moderately effective nitazoxanide is the only drug approved by the United States Food and Drug Administration for treating cryptosporidiosis in immunocompetent humans. However, no effective drug exists for the severe disease seen in young children, immunocompromised individuals and neonatal livestock. C. parvum lacks the Krebs cycle and the oxidative phosphorylation steps, making it dependent solely on glycolysis for metabolic energy production. Within its glycolytic pathway, C. parvum possesses two unique enzymes, the bacterial-type lactate dehydrogenase (CpLDH) and the plant-like pyruvate kinase (CpPyK), that catalyze two sequential steps for generation of essential metabolic energy. We have previously reported that inhibitors of CpLDH are effective against C. parvum, both in vitro and in vivo. Herein, we developed an in vitro assay for the enzymatic activity of recombinant CpPyK protein and used it to screen a chemical compound library for inhibitors of CpPyK’s activity. The identified inhibitors were tested (at non-toxic concentrations) for efficacy against C. parvum using in vitro assays, and an in vivo mouse infection model. We identified six CpPyK inhibitors that blocked in vitro growth and proliferation of C. parvum at low micromolar concentrations (EC50 values ranging from 10.29 to 86.01 μM) that were non-toxic to host cells. Among those six compounds, two (NSC252172 and NSC234945) were found to be highly efficacious against cryptosporidiosis in immunocompromised mice at a dose of 10 mg/kg body weight, with very significant reduction in parasite load and amelioration of intestinal pathologies. Together, these findings have unveiled inhibitors for an essential molecular target in C. parvum and demonstrated their efficacy against the parasite in vitro and in vivo. These inhibitors are, therefore, potential lead-compounds for developing efficacious treatments for cryptosporidiosis.
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Affiliation(s)
- Shahbaz M Khan
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Xuejin Zhang
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - William H Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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11
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Dominguez-Uscanga A, Aycart DF, Li K, Witola WH, Andrade Laborde JE. Anti-protozoal activity of Thymol and a Thymol ester against Cryptosporidium parvum in cell culture. Int J Parasitol Drugs Drug Resist 2021; 15:126-133. [PMID: 33647675 PMCID: PMC7932911 DOI: 10.1016/j.ijpddr.2021.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 02/04/2021] [Accepted: 02/08/2021] [Indexed: 11/26/2022]
Abstract
Cryptosporidium parvum is a protozoan parasite that infects intestinal epithelial cells causing malabsorption and severe diarrhea. The monoterpene thymol has been reported to have antifungal and antibacterial properties but less is known about the antiparasitic effect of this compound. Terpenes are sometimes unsuitable for therapeutic and food applications because of their instability. Esterification of terpenes eliminates this disadvantage. The present study evaluates the effects of thymol (Th) and a thymol ester, thymol octanoate (TO), against C. parvum infectivity in vitro. The cytotoxicity IC50 value for TO after 24 h of treatment was 309.6 μg/mL, significantly higher than that of Th (122.5 μg/mL) in a human adenocarcinoma cell line (HCT-8). In the same way, following 48 h of treatment, the cytotoxicity IC50 value for TO was significantly higher (139 μg/mL) than that of Th (75.5 μg/mL). These results indicate that esterification significantly reduces Th cytotoxicity. Dose-dependent effects were observed for TO and Th when both parasite invasion and parasite growth assays were evaluated. When evaluated for their activity against C. parvum growth cultured in vitro in HCT-8 cells, the anti-cryptosporidial IC50 values were 35.5 and 7.5 μg/mL, for TO and Th, respectively. Together, these findings indicate that esterified thymol has anti-cryptosporidial effect comparable with its parental compound thymol, but with improved safety margins in mammalian cells and better physicochemical properties that could make it more suitable for diverse applications as an antiparasitic agent.
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Affiliation(s)
- Astrid Dominguez-Uscanga
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Danielle Francesca Aycart
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Facultad de Ciencias de la Vida, Escuela Superior Politécnica del Litoral, Guayaquil, Ecuador
| | - Kun Li
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, 61801, USA
| | - William H Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, 61801, USA
| | - Juan E Andrade Laborde
- Food Science and Human Nutrition Department, University of Florida, Gainesville, FL, 32611, USA.
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12
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Li K, Grooms GM, Khan SM, Hernandez AG, Witola WH, Stec J. Novel acyl carbamates and acyl / diacyl ureas show in vitro efficacy against Toxoplasma gondii and Cryptosporidium parvum. Int J Parasitol Drugs Drug Resist 2020; 14:80-90. [PMID: 33011650 PMCID: PMC7529613 DOI: 10.1016/j.ijpddr.2020.08.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/07/2020] [Accepted: 08/19/2020] [Indexed: 11/28/2022]
Abstract
Toxoplasma gondii and Cryptosporidium parvum are protozoan parasites that are highly prevalent and opportunistically infect humans worldwide, but for which completely effective and safe medications are lacking. Herein, we synthesized a series of novel small molecules bearing the diacyl urea scaffold and related structures, and screened them for in vitro cytotoxicity and antiparasitic activity against T. gondii and C. parvum. We identified one compound (GMG-1-09), and four compounds (JS-1-09, JS-2-20, JS-2-35 and JS-2-49) with efficacy against C. parvum and T. gondii, respectively, at low micromolar concentrations and showed appreciable selectivity in human host cells. Among the four compounds with efficacy against T. gondii, JS-1-09 representing the diacyl urea scaffold was the most effective, with an anti-Toxoplasma IC50 concentration (1.21 μM) that was nearly 53-fold lower than its cytotoxicity IC50 concentration, indicating that this compound has a good selectivity index. The other three compounds (JS-2-20, JS-2-35 and JS-2-49) were structurally more divergent from JS-1-09 as they represent the acyl urea and acyl carbamate scaffold. This appeared to correlate with their anti-Toxoplasma activity, suggesting that these compounds' potency can likely be enhanced by selective structural modifications. One compound, GMG-1-09 representing acyl carbamate scaffold, depicted in vitro efficacy against C. parvum with an IC50 concentration (32.24 μM) that was 14-fold lower than its cytotoxicity IC50 concentration in a human intestinal cell line. Together, our studies unveil a series of novel synthetic acyl/diacyl urea and acyl carbamate scaffold-based small molecule compounds with micromolar activity against T. gondii and C. parvum that can be explored further for the development of the much-needed novel anti-protozoal drugs.
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Affiliation(s)
- Kun Li
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
| | - Gregory M Grooms
- Chicago State University, College of Pharmacy, Department of Pharmaceutical Sciences, 9501 S. King Drive, Chicago, IL 60628, USA
| | - Shahbaz M Khan
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
| | - Anolan Garcia Hernandez
- Chicago State University, College of Pharmacy, Department of Pharmaceutical Sciences, 9501 S. King Drive, Chicago, IL 60628, USA
| | - William H Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA.
| | - Jozef Stec
- Chicago State University, College of Pharmacy, Department of Pharmaceutical Sciences, 9501 S. King Drive, Chicago, IL 60628, USA; Marshall B. Ketchum University, College of Pharmacy, Department of Pharmaceutical Sciences, 2575 Yorba Linda Blvd., Fullerton, CA 82831, USA.
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13
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Abugri DA, Witola WH. Interaction of apigenin-7-O-glucoside with pyrimethamine against Toxoplasma gondii growth. J Parasit Dis 2020; 44:221-229. [PMID: 32174728 PMCID: PMC7046874 DOI: 10.1007/s12639-019-01185-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 11/25/2019] [Indexed: 12/24/2022] Open
Abstract
Apigenin-7-O-glucoside, a flavonoid glucoside known to inhibit cancer cell growth, fungi growth, both intra and extracellular reactive oxygen species generation, causing cell arrest and damage to the plasma membrane, was tested alone or in combination with a dihydrofolate inhibitor (pyrimethamine) against Toxoplasma gondii (T. gondii) growth. The anti-T. gondii activity was carried out using a high throughput antiparasitic drug screening cell-based assay known as 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H tetrazolium, monosodium salt (WST-8) and fluorescence plate reader. The 50% effective concentration inhibition and 95% confidence interval values for individual and combination treatments against T. gondii were 0.80 (0.38-1.29) µg/mL, 1.05 (0.275-2.029) µg/mL, and 0.40 (0-1.06) µg/mL for apigenin-7-O-glucoside, pyrimethamine, and apigenin-7-O-glucoside plus pyrimethamine, respectively. Interestingly, the apigenin-7-O-glucoside plus pyrimethamine combination showed an additive inhibition effect against T. gondii growth in vitro using the fractional inhibitory concentration index method. It was discovered that the apigenin-7-O-glucoside combination with pyrimethamine had a high selectivity index 62.5, which implies 62-fold inhibition activity against the parasite versus human foreskin fibroblast cell cytotoxicity. This new combination hit is novel and will have the potential for future effective, safe, and less costly anti-Toxoplasma drug development, if its in vivo activity shows similar findings.
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Affiliation(s)
- Daniel A. Abugri
- Department of Chemistry, Laboratory of Ethnomedicine, Parasitology and Drug Discovery, Tuskegee University, Tuskegee, AL 36088 USA
- Department of Biology, Tuskegee University, Tuskegee, AL 36088 USA
| | - William H. Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois, 2432 VMBSB, MC-002, 2001 South Lincoln Avenue, Urbana, Champaign, IL USA
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14
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Wilke G, Wang Y, Ravindran S, Stappenbeck T, Witola WH, Sibley LD. In Vitro Culture of Cryptosporidium parvum Using Stem Cell-Derived Intestinal Epithelial Monolayers. Methods Mol Biol 2020; 2052:351-372. [PMID: 31452172 DOI: 10.1007/978-1-4939-9748-0_20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cryptosporidium parvum has a complex life cycle consisting of asexual and sexual phases that culminate in oocyst formation in vivo. The most widely used cell culture platforms to study C. parvum only support a few days of growth and do not allow the parasite to proceed past the sexual stages to complete oocyst formation. Additionally, these cell culture platforms are mostly adenocarcinoma cell lines, which do not adequately model the parasite's natural environment in the small intestine. We describe here a method to create primary intestinal epithelial cell monolayers that support long-term C. parvum growth. Monolayers were derived from mouse intestinal stem cells grown as spheroids and plated onto transwells, allowing for separate apical and basolateral compartments. In the apical chamber, the cell growth medium was removed to create an "air-liquid interface" that enhanced host cell differentiation and supported long-term C. parvum growth. The use of primary intestinal cells to grow C. parvum in vitro will be a valuable tool for studying host-parasite interactions using a convenient in vitro model that more closely resembles the natural niche in the intestine.
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Affiliation(s)
- Georgia Wilke
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, USA
| | - Yi Wang
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA
| | - Soumya Ravindran
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, USA
| | - Thaddeus Stappenbeck
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA
| | - William H Witola
- Department of Pathobiology, University of Illinois College of Veterinary Medicine, Urbana, IL, USA
| | - L David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, USA.
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15
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Abstract
Objective Toxoplasma gondii, an intracellular zoonotic parasite, infects approximately a third of the world population. Current drugs for treatment of T. gondii infection have been challenged with ineffectiveness and adverse side effects. This necessitates development of new anti-Toxoplasma drugs. Sorghum bicolor [Moench] leaf extract has been used in African traditional medicine for the management of anemia and treatment of infectious diseases. We tested the in vitro anti-Toxoplasma inhibitory activity of S. bicolor’s oil-like crude extracts and fractions against T. gondii and determined their cytotoxic effects on human host cells. Results Significant inhibitory activities against the growth of T. gondii tachyzoites were observed for the crude extract (IC50 = 3.65 µg/mL), the hexane-methanol fraction (IC50 = 2.74 µg/mL), and the hexane fraction (IC50 = 3.55 µg/mL) after 48 h of culture. The minimum cytotoxicity concentrations against HFF were 34.41, 16.92 and 7.23 µg/mL for crude extract, hexane-methanol and hexane fractions, respectively. The crude extract and fractions showed high antiparasitic effects with low cytotoxic effects. Further studies to determine synergistic activities and modes of action would provide impetus for the development of new toxoplasmosis drugs or nutraceuticals.
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Affiliation(s)
- Daniel A Abugri
- Department of Chemistry and Department of Biology, Laboratory of Ethnomedicine, Parasitology and Drug Discovery, College of Arts and Sciences, Tuskegee University, Tuskegee, AL, USA.
| | - Jesse M Jaynes
- Department of Agricultural and Environmental Sciences, College of Agriculture, Environment and Nutrition Sciences, Tuskegee University, Tuskegee, AL, 36088, USA
| | - William H Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana-Champaign, IL, 61802, USA
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Li K, Nader SM, Zhang X, Ray BC, Kim CY, Das A, Witola WH. Novel lactate dehydrogenase inhibitors with in vivo efficacy against Cryptosporidium parvum. PLoS Pathog 2019; 15:e1007953. [PMID: 31356619 PMCID: PMC6687188 DOI: 10.1371/journal.ppat.1007953] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [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: 03/01/2019] [Revised: 08/08/2019] [Accepted: 07/01/2019] [Indexed: 11/18/2022] Open
Abstract
Cryptosporidium parvum is a highly prevalent zoonotic and anthroponotic protozoan parasite that causes a diarrheal syndrome in children and neonatal livestock, culminating in growth retardation and mortalities. Despite the high prevalence of C. parvum, there are no fully effective and safe drugs for treating infections, and there is no vaccine. We have previously reported that the bacterial-like C. parvum lactate dehydrogenase (CpLDH) enzyme is essential for survival, virulence and growth of C. parvum in vitro and in vivo. In the present study, we screened compound libraries and identified inhibitors against the enzymatic activity of recombinant CpLDH protein in vitro. We tested the inhibitors for anti-Cryptosporidium effect using in vitro infection assays of HCT-8 cells monolayers and identified compounds NSC158011 and NSC10447 that inhibited the proliferation of intracellular C. parvum in vitro, with IC50 values of 14.88 and 72.65 μM, respectively. At doses tolerable in mice, we found that both NSC158011 and NSC10447 consistently significantly reduced the shedding of C. parvum oocysts in infected immunocompromised mice’s feces, and prevented intestinal villous atrophy as well as mucosal erosion due to C. parvum. Together, our findings have unveiled promising anti-Cryptosporidium drug candidates that can be explored further for the development of the much needed novel therapeutic agents against C. parvum infections. Cryptosporidium parvum is a protozoan parasite that can cause a life-threatening gastrointestinal disease in children and in immunocompromised adults. The only approved drug for treatment of Cryptosporidium infections in humans is nitazoxanide, but it is not effective in immunocompromised individuals or in children with malnutrition. C. parvum possesses a unique lactate dehydrogenase (CpLDH) enzyme that it uses for generating metabolic energy (ATP) via the glycolytic pathway to fuel its growth and proliferation in the host. We have identified novel inhibitors for the enzymatic activity of CpLDH. Further, we have demonstrated that two of the CpLDH inhibitors effectively block the growth, proliferation and pathogenicity of C. parvum at tolerable doses in immunocompromised mice. Together, our findings have unveiled novel CpLDH inhibitors that can be explored for the development of efficacious therapeutic drugs against C. parvum infections.
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Affiliation(s)
- Kun Li
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Sara M. Nader
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Xuejin Zhang
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Benjamin C. Ray
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Chi Yong Kim
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Aditi Das
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - William H. Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- * E-mail:
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17
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Zhang X, Kim CY, Worthen T, Witola WH. Morpholino-mediated in vivo silencing of Cryptosporidium parvum lactate dehydrogenase decreases oocyst shedding and infectivity. Int J Parasitol 2018. [PMID: 29530646 PMCID: PMC6018611 DOI: 10.1016/j.ijpara.2018.01.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An in vivo morpholino-based approach for targeted gene knockdown of genes in Cryptosporidium parvum was developed. Cryptosporidium parvum lactate dehydrogenase, and sporozoite 60K were knocked down sustainably in infected mice. Cryptosporidium parvum lactate dehydrogenase knockdown significantly decreased oocyst shedding and infectivity.
Cryptosporidium is a highly prevalent protozoan parasite that is the second leading cause of childhood morbidity and mortality due to diarrhoea in developing countries, and causes a serious diarrheal syndrome in calves, lambs and goat kids worldwide. Development of fully effective drugs against Cryptosporidium has mainly been hindered by the lack of genetic tools for functional characterization and validation of potential molecular drug targets in the parasite. Herein, we report the development of a morpholino-based in vivo approach for Cryptosporidium parvum gene knockdown to facilitate determination of the physiological roles of the parasite’s genes in a murine model. We show that, when administered intraperitoneally at non-toxic doses, morpholinos targeting C. parvum lactate dehydrogenase (CpLDH) and sporozoite 60K protein (Cp15/60) were able to specifically and sustainably down-regulate the expression of CpLDH and Cp15/60 proteins, respectively, in C. parvum-infected interferon-γ knockout mice. Over a period of 6 days of daily administration of target morpholinos, CpLDH and Cp15/60 proteins were down-regulated by 20- to 50-fold, and 10- to 20-fold, respectively. Knockdown of CpLDH resulted in approximately 80% reduction in oocyst load in the feces of mice, and approximately 70% decrease in infectivity of the sporozoites excysted from the shed oocysts. Cp15/60 knockdown did not affect oocyst shedding nor infectivity but, nevertheless, provided a proof-of-principle for the resilience of the morpholino-mediated C. parvum gene knockdown system in vivo. Together, our findings provide a genetic tool for deciphering the physiological roles of C. parvum genes in vivo, and validate CpLDH as an essential gene for the growth and viability of C. parvum in vivo.
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Affiliation(s)
- Xuejin Zhang
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana-Champaign, USA
| | - Chi Yong Kim
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana-Champaign, USA
| | - Tori Worthen
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana-Champaign, USA
| | - William H Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana-Champaign, USA.
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18
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Abugri DA, Witola WH, Jaynes JM. In vitro antagonistic and indifferent activity of combination of 3-deoxyanthocyanidins against Toxoplasma gondii. Parasitol Res 2017; 116:3387-3400. [PMID: 29086004 DOI: 10.1007/s00436-017-5661-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [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: 03/21/2017] [Accepted: 10/18/2017] [Indexed: 10/18/2022]
Abstract
Toxoplasma gondii is a ubiquitous intracellular zoonotic parasite estimated to affect about 30-90% of the world's human population. The most affected are immunocompromised individuals such as HIV-AIDS and cancer patients, organ and tissue transplant recipients, and congenitally infected children. No effective and safe drugs and vaccines are available against all forms of the parasite. We report here the antagonistic and indifferent activity of the combination of five different formulations of pure synthetic 3-deoxyanthocyaninidin (3-DA) chloride compounds against T. gondii tachyzoites and the synergistic and additive interaction against a human foreskin fibroblast (HFF) cell line in vitro using fluorescence microscopy, trypan blue assay, and fractional inhibitory concentration index. The individual and the combined pure 3-DA compounds were observed to have effective inhibition against T. gondii parasites with less cytotoxic effect in a ratio of 1:1. The IC50 values for parasite inhibition ranged from 1.88 μg/mL (1.51-2.32 μg/mL) for luteolinindin plus 7-methoxyapigeninindin (LU/7-MAP) and 2.23 μg/mL (1.66-2.97 μg/mL) for apigeninindin plus 7-methoxyapigeninindin (AP/7-MAP) combinations at 95% confidence interval (CI) after 48 h of culture. We found LU/7-MAP to be antagonistic and AP/7-MAP to be indifferent in interaction against T. gondii growth. Both individual and combination 3-DA compounds not only depicted very strong inhibitory activity against T. gondii, but also had synergistic and additive cytotoxic effects against HFF cells. These synthetic 3-DAs have potential as antiparasitic agents for the treatment of human toxoplasmosis.
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Affiliation(s)
- Daniel A Abugri
- Department of Chemistry, College of Arts and Sciences, Laboratory of Ethnomedicine, Parasitology and Drug Discovery, Tuskegee University, Tuskegee, USA. .,Department of Biology, College of Arts and Sciences, Tuskegee University, Tuskegee, AL, USA.
| | - William H Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, IL, 61802, USA
| | - Jesse M Jaynes
- Department of Agricultural and Environmental Sciences, College of Agriculture, Environment and Nutrition Sciences, Tuskegee University, Tuskegee, AL, USA
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19
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Abugri DA, Witola WH, Russell AE, Troy RM. In vitro activity of the interaction between taxifolin (dihydroquercetin) and pyrimethamine against Toxoplasma gondii. Chem Biol Drug Des 2017; 91:194-201. [PMID: 28696589 DOI: 10.1111/cbdd.13070] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [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: 03/05/2017] [Revised: 06/19/2017] [Accepted: 07/02/2017] [Indexed: 11/26/2022]
Abstract
Toxoplasmosis is one of the most neglected zoonotic foodborne parasitic diseases that cause public health and socioeconomic concern worldwide. The current drugs used for the treatment of toxoplasmosis have been identified to have clinical limitations. Hence, new drugs are urgently needed to eradicate T.gondii infections globally. Here, an in vitro anti-Toxoplasma gondii activity of taxifolin (dihydroquercetin) and dihydrofolate inhibitor (pyrimethamine) alone and in combination with a fixed concentration of pyrimethamine were investigated against the rapidly proliferating T.gondii RH strain at 48 hr using colorimetric assay. Pyrimethamine showed the highest anti-T. gondii activity with IC50P of 0.84 μg/ml (p > .05), respectively. The combination of pyrimethamine with dihydroquercetin gave a significant inhibitory activity against tachyzoites in in vitro with IC50p of 1.39 μg/ml (p < .05). The IC50p ranges obtained for the individual and the combination of taxifolin with pyrimethamine inhibition of parasite growth were not cytotoxic to the infected HFF and Hek-293 cell lines used. These compounds combination should be investigated further using in vivo model of toxoplasmosis.
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Affiliation(s)
- Daniel A Abugri
- Department of Chemistry, Tuskegee University, Tuskegee, AL, USA.,Department of Biology, Tuskegee University, Tuskegee, AL, USA.,Laboratory of Ethnomedicine, Parasitology and Drug Discovery, Tuskegee University, Tuskegee, AL, USA
| | - William H Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana Champaign, IL, USA
| | | | - Roberta M Troy
- Department of Biology, Tuskegee University, Tuskegee, AL, USA
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20
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Witola WH, Cooks-Fagbodun S, Ordonez AR, Matthews K, Abugri DA, McHugh M. Knockdown of phosphoethanolamine transmethylation enzymes decreases viability of Haemonchus contortus. Vet Parasitol 2016; 223:1-6. [PMID: 27198768 DOI: 10.1016/j.vetpar.2016.04.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 04/06/2016] [Accepted: 04/07/2016] [Indexed: 01/19/2023]
Abstract
The phosphobase methylation pathway, in which phosphoethanolamine N-methyltransferases (PMTs) successively catalyze the methylation of phosphoethanolamine to phosphocholine, is essential in the free-living nematode Caenorhabditis elegans. Two PMT-encoding genes (HcPMT1 and HcPMT2) cloned from Haemonchus contortus have been shown, by in vitro assays, to possess enzymatic characteristics similar to those of C. elegans PMTs, but their physiological significance in H. contortus is yet to be elucidated. Therefore, in this study, we endeavored to determine the importance of HcPMT1 and HcPMT2 in the survival of H. contortus by adapting the use of phosphorodiamidate morpholino oligomers (PPMO) antisense approach to block the translation of HcPMT1 and HcPMT2 in the worms. We found that PPMOs targeting HcPMT1 and HcPMT2 down-regulated the expression of HcPMT1 and HcPMT2 proteins in adult H. contortus. Analysis of the effect of HcPMT1 and HcPMT2 knockdown showed that it significantly decreased worm motility and viability, thus validating HcPMT1 and HcPMT2 as essential enzymes for survival of H. contortus. Studies of gene function in H. contortus have been constrained by limited forward and reverse genetic technologies for use in H. contortus. Thus, our success in adaptation of use of PPMO antisense approach in H. contortus provides an important reverse genetic technological advance for studying this parasitic nematode of veterinary significance.
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Affiliation(s)
- William H Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, USA.
| | - Sheritta Cooks-Fagbodun
- Department of Agricultural and Environmental Sciences, Tuskegee University, Tuskegee, AL, USA
| | - Adriana Reyes Ordonez
- Department of Agricultural and Environmental Sciences, Tuskegee University, Tuskegee, AL, USA
| | - Kwame Matthews
- Department of Agricultural and Environmental Sciences, Tuskegee University, Tuskegee, AL, USA
| | - Daniel A Abugri
- Department of Agricultural and Environmental Sciences, Tuskegee University, Tuskegee, AL, USA
| | - Mark McHugh
- Department of Agricultural and Environmental Sciences, Tuskegee University, Tuskegee, AL, USA
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21
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Abugri DA, Witola WH, Jaynes JM, Toufic N. In vitro activity of Sorghum bicolor extracts, 3-deoxyanthocyanidins, against Toxoplasma gondii. Exp Parasitol 2016; 164:12-9. [PMID: 26855040 DOI: 10.1016/j.exppara.2016.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [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: 04/06/2015] [Revised: 01/29/2016] [Accepted: 02/03/2016] [Indexed: 10/22/2022]
Abstract
We investigated dried red leaf extracts of Sorghum bicolor for activity against Toxoplasma gondii tachyzoites. S. bicolor red leaf extracts were obtained by bioassay-guided fractionation using ethanol and ethyl acetate as solvents. Analysis of the crude and fractionated extracts from S. bicolor using electrospray ionization mass spectrometry (ESI-MS) showed that they contained significant amounts of apigeninidin, luteolinidin, 7-methoxyapigeninidin, 5-methoxyapigeninidin, 5-methoxyluteolinidin, 7-methoxyluteolinidin 5,7-dimethoxyapigeninidin or 5,7-dimethoxyluteolinidin, based on mass per charge (m/z). When tested in vitro, the IC50s for inhibitory activity against T. gondii tachyzoites' growth of the ethanol and ethyl acetate extracts were 2.3- and 4-fold, respectively, lower than their cytotoxic IC50s in mammalian cells. Ethyl acetate extracts fractionated in chloroform-methanol and chloroform had IC50s against T. gondii that were 56.1- and 3-fold lower than their respective cytotoxic IC50s in mammalian cells. These antiparasitic activities were found to be consistent with those of the respective pure 3-deoxyanthocyanidin compounds identified to be contained in the fractions in significant amounts. Further, we observed that, the position and number of methoxy groups possessed by the 3-deoyanthocyanidins influenced their antiparasitic activity. Together, our findings indicate that S. bicolor red-leaf 3-deoxyanthocyanidins-rich extracts have potent in vitro inhibitory activity against the proliferative stage of T. gondii parasites.
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Affiliation(s)
- Daniel A Abugri
- Department of Chemistry, College of Arts and Sciences, Tuskegee University, Tuskegee, AL, USA; Department of Agricultural and Environmental Sciences, College of Agriculture, Environment and Nutrition Sciences, Tuskegee University, Tuskegee, AL, USA
| | - William H Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana-Champaign, USA.
| | - Jesse M Jaynes
- Department of Agricultural and Environmental Sciences, College of Agriculture, Environment and Nutrition Sciences, Tuskegee University, Tuskegee, AL, USA
| | - Nashar Toufic
- Department of Pathobiology, College of Veterinary Medicine, Nursing & Allied Health, Tuskegee University, Tuskegee, AL, USA
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Witola WH, Matthews K, McHugh M. In vitro anthelmintic efficacy of inhibitors of phosphoethanolamine Methyltransferases in Haemonchus contortus. Int J Parasitol Drugs Drug Resist 2016; 6:44-53. [PMID: 27054063 PMCID: PMC4805780 DOI: 10.1016/j.ijpddr.2016.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Revised: 01/12/2016] [Accepted: 01/12/2016] [Indexed: 12/03/2022]
Abstract
The essential phosphobase methylation pathway for synthesis of phosphocholine is unique to nematodes, protozoa and plants, and thus an attractive antiparasitic molecular target. Herein, we screened compounds from the National Cancer Institute (Developmental Therapeutics Program Open Chemical Repository) for specific inhibitory activity against Haemonchus contortus phosphoethanolamine methyltransferases (HcPMT1 and HcPMT2), and tested candidate compounds for anthelmintic activity against adult and third-stage larvae of H. contortus. We identified compound NSC-641296 with IC50 values of 8.3 ± 1.1 μM and 5.1 ± 1.8 μM for inhibition of the catalytic activity of HcPMT1 alone and HcPMT1/HcPMT2 combination, respectively. Additionally we identified compound NSC-668394 with inhibitory IC50 values of 5.9 ± 0.9 μM and 2.8 ± 0.6 μM for HcPMT1 alone and HcPMT1/HcPMT2 combination, respectively. Of the two compounds, NSC-641296 depicted significant anthelmintic activity against third-stage larvae (IC50 = 15 ± 2.9 μM) and adult stages (IC50 = 7 ± 2.9 μM) of H. contortus, with optimal effective in vitro concentrations being 2-fold and 4-fold, respectively, lower than its cytotoxic IC50 (29 ± 2.1 μM) in a mammalian cell line. Additionally, we identified two compounds, NSC-158011 and NSC-323241, with low inhibitory activity against the combined activity of HcPMT1 and HcPMT2, but both compounds did not show any anthelmintic activity against H. contortus. The identification of NSC-641296 that specifically inhibits a unique biosynthetic pathway in H. contortus and has anthelmintic activity against both larval and adult stages of H. contortus, provides impetus for the development of urgently needed new efficacious anthelmintics to address the prevailing problem of anthelmintic-resistant H. contortus. NSC-641296 and NSC-668394 inhibit HcPMT1 and HcPMT2 enzymes in Haemonchus contortus. NSC-641296 has in vitro anthelmintic activity against larvae and adult H. contortus. H. contortus HcPMT1 and HcPMT2 are two unique targets for anthelmintic development.
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Affiliation(s)
- William H Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana-Champaign, USA.
| | - Kwame Matthews
- Department of Agricultural and Environmental Sciences, Tuskegee University, Tuskegee, AL, USA
| | - Mark McHugh
- Department of Agricultural and Environmental Sciences, Tuskegee University, Tuskegee, AL, USA
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Witola WH, Bauman B, McHugh M, Matthews K. Silencing of GRA10 protein expression inhibits Toxoplasma gondii intracellular growth and development. Parasitol Int 2014; 63:651-8. [PMID: 24832208 DOI: 10.1016/j.parint.2014.05.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [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: 12/21/2013] [Revised: 03/29/2014] [Accepted: 05/02/2014] [Indexed: 02/01/2023]
Abstract
Toxoplasma gondii dense granule proteins (GRAs) are secreted abundantly in both the tachyzoite and bradyzoite stages of the parasite and are known to localize to various compartments of the parasitophorous vacuole (PV) that interfaces with the host cell milieu. Thus, GRAs may play significant roles in the biogenesis of the PV that is important for survival of intracellular T. gondii. GRA10 is a dense granule protein whose role in T. gondii has not yet been characterized. Therefore, in this study, we endeavored to determine the role of GRA10 in the growth and survival of intracellular T. gondii by using phosphorodiamidate morpholino oligomers (PPMOs) antisense knockdown approach to disrupt the translation of GRA10 mRNA in the parasites. We expressed and purified a truncated recombinant GRA10 protein to generate anti-GRA10 polyclonal antibodies that we used to characterize GRA10 in T. gondii. We found that GRA10 is a soluble, dense granule-associated protein that is secreted into the parasite cytosol and the parasitophorous vacuole milieu. Using in vitro cultures, we found that knockdown of GRA10 results in severe inhibition of T. gondii growth in human fibroblasts and in ovine monocytic cells. Together, our findings define GRA10 as a dense granule protein that plays a significant role in the growth and propagation of intracellular T. gondii in human fibroblasts and in ovine monocytic cells.
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Affiliation(s)
- William H Witola
- Room 312 Milbank Hall, College of Agriculture, Environment and Nutrition Sciences, Tuskegee University, Tuskegee, AL 36088, USA.
| | - Bretta Bauman
- Room 312 Milbank Hall, College of Agriculture, Environment and Nutrition Sciences, Tuskegee University, Tuskegee, AL 36088, USA
| | - Mark McHugh
- Room 312 Milbank Hall, College of Agriculture, Environment and Nutrition Sciences, Tuskegee University, Tuskegee, AL 36088, USA
| | - Kwame Matthews
- Room 312 Milbank Hall, College of Agriculture, Environment and Nutrition Sciences, Tuskegee University, Tuskegee, AL 36088, USA
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Stec J, Huang Q, Pieroni M, Kaiser M, Fomovska A, Mui E, Witola WH, Bettis S, McLeod R, Brun R, Kozikowski AP. Synthesis, biological evaluation, and structure-activity relationships of N-benzoyl-2-hydroxybenzamides as agents active against P. falciparum (K1 strain), Trypanosomes, and Leishmania. J Med Chem 2012; 55:3088-100. [PMID: 22352841 DOI: 10.1021/jm2015183] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In our efforts to identify novel chemical scaffolds for the development of new antiprotozoal drugs, a compound library was screened against Toxoplasma gondii tachyzoites with activity discovered for N-(4-ethylbenzoyl)-2-hydroxybenzamide 1a against T. gondii as described elsewhere. Synthesis of a compound set was guided by T. gondii SAR with 1r found to be superior for T. gondii , also active against Thai and Sierra Leone strains of Plasmodium falciparum , and with superior ADMET properties as described elsewhere. Herein, synthesis methods and details of the chemical analysis of the compounds in this series are described. Further, this series of N-benzoyl-2-hydroxybenzamides was repurposed for testing against four other protozoan parasites: Trypanosoma brucei rhodesiense , Trypanosoma cruzi , Leishmania donovani , and P. falciparum (K1 isolate). Structure-activity analyses led to the identification of compounds in this set with excellent antileishmanial activity (compound 1d). Overall, compound 1r was the best and had activity 21-fold superior to that of the standard antimalarial drug chloroquine against the K1 P. falciparum isolate.
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Affiliation(s)
- Jozef Stec
- Drug Discovery Program, Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, 833 South Wood Street, Chicago, Illinois 60612, USA
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25
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Cong H, Mui EJ, Witola WH, Sidney J, Alexander J, Sette A, Maewal A, McLeod R. Human immunome, bioinformatic analyses using HLA supermotifs and the parasite genome, binding assays, studies of human T cell responses, and immunization of HLA-A*1101 transgenic mice including novel adjuvants provide a foundation for HLA-A03 restricted CD8+T cell epitope based, adjuvanted vaccine protective against Toxoplasma gondii. Immunome Res 2010; 6:12. [PMID: 21129215 PMCID: PMC3009956 DOI: 10.1186/1745-7580-6-12] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Accepted: 12/03/2010] [Indexed: 11/17/2022] Open
Abstract
Background Toxoplasmosis causes loss of life, cognitive and motor function, and sight. A vaccine is greatly needed to prevent this disease. The purpose of this study was to use an immmunosense approach to develop a foundation for development of vaccines to protect humans with the HLA-A03 supertype. Three peptides had been identified with high binding scores for HLA-A03 supertypes using bioinformatic algorhythms, high measured binding affinity for HLA-A03 supertype molecules, and ability to elicit IFN-γ production by human HLA-A03 supertype peripheral blood CD8+ T cells from seropositive but not seronegative persons. Results Herein, when these peptides were administered with the universal CD4+T cell epitope PADRE (AKFVAAWTLKAAA) and formulated as lipopeptides, or administered with GLA-SE either alone, or with Pam2Cys added, we found we successfully created preparations that induced IFN-γ and reduced parasite burden in HLA-A*1101(an HLA-A03 supertype allele) transgenic mice. GLA-SE is a novel emulsified synthetic TLR4 ligand that is known to facilitate development of T Helper 1 cell (TH1) responses. Then, so our peptides would include those expressed in tachyzoites, bradyzoites and sporozoites from both Type I and II parasites, we used our approaches which had identified the initial peptides. We identified additional peptides using bioinformatics, binding affinity assays, and study of responses of HLA-A03 human cells. Lastly, we found that immunization of HLA-A*1101 transgenic mice with all the pooled peptides administered with PADRE, GLA-SE, and Pam2Cys is an effective way to elicit IFN-γ producing CD8+ splenic T cells and protection. Immunizations included the following peptides together: KSFKDILPK (SAG1224-232); AMLTAFFLR (GRA6164-172); RSFKDLLKK (GRA7134-142); STFWPCLLR (SAG2C13-21); SSAYVFSVK(SPA250-258); and AVVSLLRLLK(SPA89-98). This immunization elicited robust protection, measured as reduced parasite burden using a luciferase transfected parasite, luciferin, this novel, HLA transgenic mouse model, and imaging with a Xenogen camera. Conclusions Toxoplasma gondii peptides elicit HLA-A03 restricted, IFN-γ producing, CD8+ T cells in humans and mice. These peptides administered with adjuvants reduce parasite burden in HLA-A*1101 transgenic mice. This work provides a foundation for immunosense based vaccines. It also defines novel adjuvants for newly identified peptides for vaccines to prevent toxoplasmosis in those with HLA-A03 supertype alleles.
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Affiliation(s)
- Hua Cong
- Departments of Surgery (Ophthalmology and Visual Sciences) and Pediatrics (Infectious Disease), Committees on Immunology, Molecular Medicine, and Genetics, Institute of Genomics and Systems Biology, and The College, The University of Chicago, Chicago, Illinois 60637, USA.
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Hutson SL, Mui E, Kinsley K, Witola WH, Behnke MS, El Bissati K, Muench SP, Rohrman B, Liu SR, Wollmann R, Ogata Y, Sarkeshik A, Yates JR, McLeod R. T. gondii RP promoters & knockdown reveal molecular pathways associated with proliferation and cell-cycle arrest. PLoS One 2010; 5:e14057. [PMID: 21124925 PMCID: PMC2989910 DOI: 10.1371/journal.pone.0014057] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [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: 06/03/2010] [Accepted: 10/25/2010] [Indexed: 01/16/2023] Open
Abstract
Molecular pathways regulating rapid proliferation and persistence are fundamental for pathogens but are not elucidated fully in Toxoplasma gondii. Promoters of T. gondii ribosomal proteins (RPs) were analyzed by EMSAs and ChIP. One RP promoter domain, known to bind an Apetela 2, bound to nuclear extract proteins. Promoter domains appeared to associate with histone acetyl transferases. To study effects of a RP gene's regulation in T. gondii, mutant parasites (Δrps13) were engineered with integration of tetracycline repressor (TetR) response elements in a critical location in the rps13 promoter and transfection of a yellow fluorescent-tetracycline repressor (YFP-TetR). This permitted conditional knockdown of rps13 expression in a tightly regulated manner. Δrps13 parasites were studied in the presence (+ATc) or absence of anhydrotetracycline (-ATc) in culture. -ATc, transcription of the rps13 gene and expression of RPS13 protein were markedly diminished, with concomitant cessation of parasite replication. Study of Δrps13 expressing Myc-tagged RPL22, -ATc, showed RPL22 diminished but at a slower rate. Quantitation of RNA showed diminution of 18S RNA. Depletion of RPS13 caused arrest of parasites in the G1 cell cycle phase, thereby stopping parasite proliferation. Transcriptional differences ±ATc implicate molecules likely to function in regulation of these processes. In vitro, -ATc, Δrps13 persists for months and the proliferation phenotype can be rescued with ATc. In vivo, however, Δrps13 could only be rescued when ATc was given simultaneously and not at any time after 1 week, even when L-NAME and ATc were administered. Immunization with Δrps13 parasites protects mice completely against subsequent challenge with wildtype clonal Type 1 parasites, and robustly protects mice against wildtype clonal Type 2 parasites. Our results demonstrate that G1 arrest by ribosomal protein depletion is associated with persistence of T. gondii in a model system in vitro and immunization with Δrps13 protects mice against subsequent challenge with wildtype parasites.
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Affiliation(s)
- Samuel L. Hutson
- Department of Surgery (Ophthalmology), The University of Chicago, Chicago, Illinois, United States of America
| | - Ernest Mui
- Department of Surgery (Ophthalmology), The University of Chicago, Chicago, Illinois, United States of America
| | - Karen Kinsley
- Department of Surgery (Ophthalmology), The University of Chicago, Chicago, Illinois, United States of America
| | - William H. Witola
- Department of Surgery (Ophthalmology), The University of Chicago, Chicago, Illinois, United States of America
| | - Michael S. Behnke
- Department of Veterinary Molecular Biology, Montana State University, Bozeman, Montana, United States of America
| | - Kamal El Bissati
- Department of Surgery (Ophthalmology), The University of Chicago, Chicago, Illinois, United States of America
| | - Stephen P. Muench
- Institute of Membrane and Systems Biology, University of Leeds, Leeds, United Kingdom
| | - Brittany Rohrman
- Department of Surgery (Ophthalmology), The University of Chicago, Chicago, Illinois, United States of America
| | - Susan R. Liu
- Department of Surgery (Ophthalmology), The University of Chicago, Chicago, Illinois, United States of America
| | - Robert Wollmann
- Department of Pathology, The University of Chicago, Chicago, Illinois, United States of America
| | - Yuko Ogata
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Ali Sarkeshik
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, California, United States of America
| | - John R. Yates
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, California, United States of America
| | - Rima McLeod
- Department of Surgery (Ophthalmology), The University of Chicago, Chicago, Illinois, United States of America
- Department of Pediatrics (Infectious Disease), The University of Chicago, Chicago, Illinois, United States of America
- Committees on Immunology, Molecular Medicine, and Genetics, Institute of Genomics and Systems Biology, The College, The University of Chicago, Chicago, Illinois, United States of America
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27
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Cong H, Mui EJ, Witola WH, Sidney J, Alexander J, Sette A, Maewal A, McLeod R. Towards an immunosense vaccine to prevent toxoplasmosis: protective Toxoplasma gondii epitopes restricted by HLA-A*0201. Vaccine 2010; 29:754-62. [PMID: 21095258 DOI: 10.1016/j.vaccine.2010.11.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 10/29/2010] [Accepted: 11/06/2010] [Indexed: 10/18/2022]
Abstract
The ideal vaccine to protect against toxoplasmosis in humans would include antigens that elicit a protective T helper cell type 1 immune response, and generate long-lived IFN-γ-producing CD8(+) T cells. Herein, we utilized a predictive algorithm to identify candidate HLA-A02 supertype epitopes from Toxoplasma gondii proteins. Thirteen peptides elicited production of IFN-γ from PBMC of HLA-A02 supertype persons seropositive for T. gondii infection but not from seronegative controls. These peptides displayed high-affinity binding to HLA-A02 proteins. Immunization of HLA-A*0201 transgenic mice with these pooled peptides, with a universal CD4(+) epitope peptide called PADRE, formulated with adjuvant GLA-SE, induced CD8(+) T cell IFN-γ production and protected against parasite challenge. Peptides identified in this study provide candidates for inclusion in immunosense epitope-based vaccines.
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Affiliation(s)
- Hua Cong
- Department of Surgery, The University of Chicago, 5841 S. Maryland Ave., MC 2114, Chicago, IL 60637, USA
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28
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Lees MP, Fuller SJ, McLeod R, Boulter NR, Miller CM, Zakrzewski AM, Mui EJ, Witola WH, Coyne JJ, Hargrave AC, Jamieson SE, Blackwell JM, Wiley JS, Smith NC. P2X7 receptor-mediated killing of an intracellular parasite, Toxoplasma gondii, by human and murine macrophages. J Immunol 2010; 184:7040-6. [PMID: 20488797 DOI: 10.4049/jimmunol.1000012] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The P2X7R is highly expressed on the macrophage cell surface, and activation of infected cells by extracellular ATP has been shown to kill intracellular bacteria and parasites. Furthermore, single nucleotide polymorphisms that decrease receptor function reduce the ability of human macrophages to kill Mycobacterium tuberculosis and are associated with extrapulmonary tuberculosis. In this study, we show that macrophages from people with the 1513C (rs3751143, NM_002562.4:c.1487A>C) loss-of-function P2X7R single nucleotide polymorphism are less effective in killing intracellular Toxoplasma gondii after exposure to ATP compared with macrophages from people with the 1513A wild-type allele. Supporting a P2X7R-specific effect on T. gondii, macrophages from P2X7R knockout mice (P2X7R-/-) are unable to kill T. gondii as effectively as macrophages from wild-type mice. We show that P2X7R-mediated T. gondii killing occurs in parallel with host cell apoptosis and is independent of NO production.
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Affiliation(s)
- Michael P Lees
- Institute for the Biotechnology of Infectious Diseases, University of Technology, Sydney, Broadway, NSW, Australia
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29
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Tan TG, Mui E, Cong H, Witola WH, Montpetit A, Muench SP, Sidney J, Alexander J, Sette A, Grigg ME, Maewal A, McLeod R. Identification of T. gondii epitopes, adjuvants, and host genetic factors that influence protection of mice and humans. Vaccine 2010; 28:3977-89. [PMID: 20347630 DOI: 10.1016/j.vaccine.2010.03.028] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 03/09/2010] [Accepted: 03/15/2010] [Indexed: 11/19/2022]
Abstract
Toxoplasma gondii is an intracellular parasite that causes severe neurologic and ocular disease in immune-compromised and congenitally infected individuals. There is no vaccine protective against human toxoplasmosis. Herein, immunization of L(d) mice with HF10 (HPGSVNEFDF) with palmitic acid moieties or a monophosphoryl lipid A derivative elicited potent IFN-gamma production from L(d)-restricted CD8(+) T cells in vitro and protected mice. CD8(+) T cell peptide epitopes from T. gondii dense granule proteins GRA 3, 6, 7, and Sag 1, immunogenic in humans for HLA-A02(+), HLA-A03(+), and HLA-B07(+) cells were identified. Since peptide repertoire presented by MHC class I molecules to CD8(+) T cells is shaped by endoplasmic reticulum-associated aminopeptidase (ERAAP), polymorphisms in the human ERAAP gene ERAP1 were studied and associate with susceptibility to human congenital toxoplasmosis (p<0.05). These results have important implications for vaccine development.
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MESH Headings
- Adjuvants, Immunologic/pharmacology
- Aminopeptidases/genetics
- Animals
- Antigens, Protozoan/immunology
- CD8-Positive T-Lymphocytes/immunology
- Epitopes, T-Lymphocyte/immunology
- Female
- Genetic Predisposition to Disease
- HLA-A Antigens/immunology
- HLA-B Antigens/immunology
- Humans
- Interferon-gamma/immunology
- Leukocytes, Mononuclear/immunology
- Lipopeptides/immunology
- Mice
- Mice, Inbred BALB C
- Mice, Transgenic
- Minor Histocompatibility Antigens
- Models, Molecular
- Polymorphism, Genetic
- Protozoan Proteins/immunology
- Protozoan Vaccines/immunology
- Toxoplasma/immunology
- Toxoplasmosis/genetics
- Toxoplasmosis/immunology
- Toxoplasmosis, Congenital/genetics
- Toxoplasmosis, Congenital/immunology
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Affiliation(s)
- Tze Guan Tan
- Department of Surgery, Committees on Immunology, Molecular Medicine, and Genetics, Institute of Genomics and Systems Biology, and The College, The University of Chicago, Chicago, IL 60637, USA
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30
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Mekata H, Konnai S, Witola WH, Inoue N, Onuma M, Ohashi K. Molecular detection of trypanosomes in cattle in South America and genetic diversity of Trypanosoma evansi based on expression-site-associated gene 6. Infection, Genetics and Evolution 2009; 9:1301-5. [DOI: 10.1016/j.meegid.2009.07.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 07/27/2009] [Accepted: 07/29/2009] [Indexed: 11/17/2022]
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31
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Konnai S, Mekata H, Mingala CN, Abes NS, Gutierrez CA, Herrera JRV, Dargantes AP, Witola WH, Cruz LC, Inoue N, Onuma M, Ohashi K. Development and application of a quantitative real-time PCR for the diagnosis of Surra in water buffaloes. Infect Genet Evol 2009; 9:449-52. [PMID: 19460309 DOI: 10.1016/j.meegid.2009.01.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Revised: 01/07/2009] [Accepted: 01/07/2009] [Indexed: 11/26/2022]
Abstract
Trypanosoma evansi (T. evansi) causes the disease called Surra in domestic animals, which is of great economic importance in South Asian countries. In order to improve the diagnosis of Surra, we endeavored to develop a real-time PCR assay for the detection and quantification of parasites in water buffaloes using specific primers for the T. evansi Rode Trypanozoon antigen type (RoTat) 1.2 Variable Surface Glycoprotein (VSG) gene, which is a known diverse DNA region in trypanosomes. The quantitative detection limit of the assay was 10(2) trypanosomes per mL of blood, and the identity of the amplicon was confirmed in all assays by melting curve analysis. To evaluate the clinical applicability of this procedure, detection and estimation of parasitemia in blood samples obtained from water buffaloes and horses were conducted. T. evansi was detected in 17/607 (2.8%) blood samples, with parasitemia levels ranging from >10(1) to 10(7) parasites per mL of blood. Interestingly, out of the 17 PCR positive animals, 3 had previously received trypanocidal treatment and 1 had abortion history. These data indicate that real-time PCR for the estimation of putative parasitemia levels is a quantitatively and objectively applicable technique for clinical diagnosis of Surra, and could help to understand disease stage and risk of transmission of T. evansi.
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Affiliation(s)
- Satoru Konnai
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
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32
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Mekata H, Konnai S, Simuunza M, Chembensofu M, Kano R, Witola WH, Tembo ME, Chitambo H, Inoue N, Onuma M, Ohashi K. Prevalence and source of trypanosome infections in field-captured vector flies (Glossina pallidipes) in southeastern Zambia. J Vet Med Sci 2008; 70:923-8. [PMID: 18840966 DOI: 10.1292/jvms.70.923] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The prevalence of trypanosome infections in tsetse flies, Glossina pallidipes, collected from Chiawa and Chakwenga in Zambia with endemic trypanosomosis was assessed by polymerase chain reaction (PCR). Out of the 550 G. pallidipes, 58 (10.5%) flies were found to harbor trypanosome DNA. Infection rates of tsetse with Trypanosoma vivax universal, Trypanosoma congolense savannah, T. congolense forest and T. congolense kilifi were 4.2% (23/550), 4.7% (26/550), 1.1% (6/550) and 1.6% (9/550), respectively. To determine the mammalian hosts of T. congolense and T. vivax infections from the tsetse flies, mammalian mitochondrion DNA of blood meal in these flies were analyzed by PCR and subsequent gene sequence analysis of the amplicons. Sequence analysis showed the presence of cytochrome b gene (cyt b) of 7 different mammalian species such as human, elephant, buffalo, goat, warthog, greater kudu and cattle. Goats which were main livestock in these areas were further examined to know the extent of its contribution in spreading the infection. We examined the prevalence of trypanosome infections in the domestic goat population in 6 settlements in Chiawa alone. Of the 86 goats sampled, 4 (4.6%), 5 (5.8%), 4 (4.6%) and 4 (4.6%) were positive for T. vivax universal, T. congolense savannah, forest and kilifi, respectively. These findings showed that the host-source of trypanosome infections in vector fly give a vital information about spread of infection. The result of this study will certainly contribute in elucidating more the epidemiology of trypanosomosis.
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Affiliation(s)
- Hirohisa Mekata
- Department of Disease Control, School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
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33
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Reynolds JM, Takebe S, Choi JY, El Bissati K, Witola WH, Bobenchik AM, Hoch JC, Voelker DR, Mamoun CB. Biochemical and genetic analysis of the phosphoethanolamine methyltransferase of the human malaria parasite Plasmodium falciparum. J Biol Chem 2008; 283:7894-900. [PMID: 18178564 DOI: 10.1074/jbc.m709869200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The PfPMT enzyme of Plasmodium falciparum, the agent of severe human malaria, is a member of a large family of known and predicted phosphoethanolamine methyltransferases (PMTs) recently identified in plants, worms, and protozoa. Functional studies in P. falciparum revealed that PfPMT plays a critical role in the synthesis of phosphatidylcholine via a plant-like pathway involving serine decarboxylation and phosphoethanolamine methylation. Despite their important biological functions, PMT structures have not yet been solved, and nothing is known about which amino acids in these enzymes are critical for catalysis and binding to S-adenosyl-methionine and phosphoethanolamine substrates. Here we have performed a mutational analysis of PfPMT focused on 24 residues within and outside the predicted catalytic motif. The ability of PfPMT to complement the choline auxotrophy of a yeast mutant defective in phospholipid methylation enabled us to characterize the activity of the PfPMT mutants. Mutations in residues Asp-61, Gly-83 and Asp-128 dramatically altered PfPMT activity and its complementation of the yeast mutant. Our analyses identify the importance of these residues in PfPMT activity and set the stage for advanced structural understanding of this class of enzymes.
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Affiliation(s)
- Jennifer M Reynolds
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Framington, CT 06030, USA
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El Bissati K, Zufferey R, Witola WH, Carter NS, Ullman B, Ben Mamoun C. The plasma membrane permease PfNT1 is essential for purine salvage in the human malaria parasite Plasmodium falciparum. Proc Natl Acad Sci U S A 2006; 103:9286-91. [PMID: 16751273 PMCID: PMC1482602 DOI: 10.1073/pnas.0602590103] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [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: 11/18/2022] Open
Abstract
The human malaria parasite Plasmodium falciparum relies on the acquisition of host purines for its survival within human erythrocytes. Purine salvage by the parasite requires specialized transporters at the parasite plasma membrane (PPM), but the exact mechanism of purine entry into the infected erythrocyte, and the primary purine source used by the parasite, remain unknown. Here, we report that transgenic parasites lacking the PPM transporter PfNT1 (P. falciparum nucleoside transporter 1) are auxotrophic for hypoxanthine, inosine, and adenosine under physiological conditions and are viable only if these normally essential nutrients are provided at excess concentrations. Transport measurements across the PPM revealed a severe reduction in hypoxanthine uptake in the knockout, whereas adenosine and inosine transport were only partially affected. These data provide compelling evidence for a sequential pathway for exogenous purine conversion into hypoxanthine using host enzymes followed by PfNT1-mediated transport into the parasite. The phenotype of the conditionally lethal mutant establishes PfNT1 as a critical component of purine salvage in P. falciparum and validates PfNT1 as a potential therapeutic target.
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Affiliation(s)
- Kamal El Bissati
- *Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT 06030-3301; and
| | - Rachel Zufferey
- *Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT 06030-3301; and
| | - William H. Witola
- *Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT 06030-3301; and
| | - Nicola S. Carter
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR 97201
| | - Buddy Ullman
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR 97201
| | - Choukri Ben Mamoun
- *Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT 06030-3301; and
- To whom correspondence should be addressed. E-mail:
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Witola WH, Pessi G, El Bissati K, Reynolds JM, Mamoun CB. Localization of the phosphoethanolamine methyltransferase of the human malaria parasite Plasmodium falciparum to the Golgi apparatus. J Biol Chem 2006; 281:21305-21311. [PMID: 16704982 DOI: 10.1074/jbc.m603260200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [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
Phosphatidylcholine is the most abundant phospholipid in the membranes of Plasmodium falciparum, the agent of severe human malaria. The synthesis of this phospholipid occurs via two routes, the CDP-choline pathway, which uses host choline as a precursor, and the plant-like serine decarboxylase-phosphoethanolamine methyltransferase (SDPM) pathway, which uses host serine as a precursor. Although various components of these pathways have been identified, their cellular locations remain unknown. We have previously reported the identification and characterization of the phosphoethanolamine methyltransferase, Pfpmt, of P. falciparum and shown that it plays a critical role in the synthesis of phosphatidylcholine via the SDPM pathway. Here we provide the first evidence that the transmethylation step of the SDPM pathway occurs in the parasite Golgi apparatus. We show that the level of Pfpmt protein in the infected erythrocyte is regulated in a stage-specific fashion, with high levels detected during the trophozoite stage at the peak of parasite membrane biogenesis. Confocal microscopy revealed that Pfpmt is not cytoplasmic. Immunoelectron microscopy revealed that Pfpmt localizes to membrane structures that extend from the nuclear membrane but that it only partially co-localizes with the endoplasmic reticulum marker BiP. Using transgenic parasites expressing green fluorescent protein targeted to different cellular compartments, a complete co-localization was detected with Rab6, a marker of the Golgi apparatus. Together these studies provide the first evidence that the transmethylation step of the SDPM pathway of P. falciparum occurs in the Golgi apparatus and indicate an important role for this organelle in parasite membrane biogenesis.
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Affiliation(s)
- William H Witola
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut 06030-3301
| | - Gabriella Pessi
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut 06030-3301
| | - Kamal El Bissati
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut 06030-3301
| | - Jennifer M Reynolds
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut 06030-3301
| | - Choukri Ben Mamoun
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut 06030-3301.
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Tsuda A, Witola WH, Konnai S, Ohashi K, Onuma M. The effect of TAO expression on PCD-like phenomenon development and drug resistance in Trypanosoma brucei. Parasitol Int 2006; 55:135-42. [PMID: 16516538 DOI: 10.1016/j.parint.2006.01.001] [Citation(s) in RCA: 6] [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] [Received: 10/11/2005] [Revised: 12/26/2005] [Accepted: 01/04/2006] [Indexed: 01/02/2023]
Abstract
Drug resistance in Trypanosoma brucei causes severe problems for people and domestic animals, but molecular mechanisms of the resistance are not well known. Programmed cell death (PCD) is a fundamental process in both multicellular and unicellular organisms, and it is speculated to be one of the important factors contributing to the emergence of drug resistance. We have previously reported that the expression of TAO appears to play a role in the inhibition of the PCD-like phenomenon development in T. brucei. In this study, to ascertain the correlation between the development of the PCD-like phenomenon and the expression of TAO in T. brucei, we genetically engineered T. brucei for conditional over-expression of the TAO gene. TAO over-expressing transgenic T. brucei was refractory to the development of the PCD-like phenomenon compared to the wild-type, indicating that expression of TAO might have a regulatory role on PCD development. Furthermore, the transgenic cells showed resistance to suramin and antrycide. We postulated that intracellular reactive oxygen species (ROS) may be involved in the mechanism of resistance to antrycide because augmentation of ROS in transgenic cells was lower than that in the wild-type cells following treatment with antrycide. These results suggest a possible correlation of PCD to drug resistance in T. brucei.
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Affiliation(s)
- Akiko Tsuda
- Laboratory of Infectious Disease, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
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Witola WH, Tsuda A, Inoue N, Ohashi K, Onuma M. Acquired resistance to berenil in a cloned isolate of Trypanosoma evansi is associated with upregulation of a novel gene, TeDR40. Parasitology 2006; 131:635-46. [PMID: 16255822 DOI: 10.1017/s003118200500836x] [Citation(s) in RCA: 10] [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] [Received: 01/12/2005] [Revised: 03/28/2005] [Accepted: 05/24/2005] [Indexed: 11/07/2022]
Abstract
Drug resistance is now a severe and increasing problem in trypanosomes, but molecular details of mechanisms of resistance are only beginning to unveil. There is urgent need to clearly elucidate the different mechanisms of drug resistance in trypanosomes in order to circumvent existing resistance problems and avoid emergence of resistance to the next generation drugs. In this study, we cloned and characterized a novel gene, TeDR40, whose expression is associated with resistance to berenil in Trypanosoma evansi. Expression analysis showed that the gene was at least 1000-fold upregulated in resistant parasites and the encoded protein appeared to have a ubiquitous cellular localization. To investigate the association of TeDR40 with berenil-resistance, we genetically modified wild-type berenil-sensitive T. evansi for inducible over-expression of the TeDR40 gene. Induction of over-expression of TeDR40 in T. evansi led to decreased (P < 0.01) sensitivity to berenil. Our findings indicate a possible correlation between over-expression of a novel gene, TeDR40, and reduced sensitivity to berenil in an in vitro-cultured clonal line of T. evansi.
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Affiliation(s)
- W H Witola
- Laboratory of Infectious Diseases, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
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Tsuda A, Witola WH, Ohashi K, Onuma M. Expression of alternative oxidase inhibits programmed cell death-like phenomenon in bloodstream form of Trypanosoma brucei rhodesiense. Parasitol Int 2005; 54:243-51. [PMID: 16115792 DOI: 10.1016/j.parint.2005.06.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2005] [Accepted: 06/27/2005] [Indexed: 01/07/2023]
Abstract
Trypanosoma brucei rhodesiense is one of the causative agents of African Trypanosomiasis. Programmed cell death (PCD) is fundamental in the development, homeostasis and immune mechanisms of multicellular organisms. It has been shown that, other than occurring in multicellular organisms, the PCD phenomenon also takes place in unicellular organisms. In the present study, we have found that under high-density axenic culture conditions, bloodstream form of T. b. rhodesiense depicts a PCD-like phenomenon. We investigated the association of the PCD-like phenomenon with expression of trypanosome alternative oxidase (TAO) under low-temperature stress conditions. We observed that bloodstream form of T. b. rhodesiense did not show any PCD but had up-regulated expression of TAO. Inhibition of TAO by the addition of ascofranone caused the development of PCD in bloodstream T. b. rhodesiense under low-temperature stress, implying that expression of TAO may contribute to the inhibition of PCD.
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Affiliation(s)
- Akiko Tsuda
- Laboratory of Infectious Disease, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
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Baticados WN, Witola WH, Inoue N, Kim JY, Kuboki N, Xuan X, Yokoyama N, Sugimoto C. Expression of a gene encoding Trypanosoma congolense putative Abc1 family protein is developmentally regulated. J Vet Med Sci 2005; 67:157-64. [PMID: 15750311 DOI: 10.1292/jvms.67.157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 11/22/2022] Open
Abstract
During the attempt to seek T. congolense species-specific diagnostic antigens, we discovered one cDNA clone (P74) encoding 74 kDa putative abc1 protein (p74) from T. congolense PCF cDNA library. It has been suggested that members of the abc1 family are novel chaperonins and essential for both the mitochondrial electron transfer in the bc 1 complex and the coenzyme Q biosynthesis. Although abc1 protein in yeast has a nuclear or mitochondrial subcellular location, neither nuclear localization signal nor mitochondrial targeting signal was found within p74. Northern blot analysis revealed that the transcription level of P74 mRNA in bloodstream form (BSF) cells were 4 times higher than that in procyclic form cells. Western blot analysis also indicated that p74 was only expressed in T. congolense BSF cells, and revealed that molecular mass of native p74 was not 74 kDa but 56 kDa. This indicates extensive post-translational modification in p74. Although further characterization of p74 will be required, our findings provide implications for CoQ biosynthesis pathway in T. congolense.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern/veterinary
- Blotting, Southern/veterinary
- Blotting, Western/veterinary
- Cloning, Molecular
- DNA Primers
- Electrophoresis, Polyacrylamide Gel
- Gene Expression Regulation, Developmental
- Gene Library
- Genes, Protozoan/genetics
- Mice/parasitology
- Mice, Inbred Strains
- Molecular Sequence Data
- Protein Structure, Tertiary
- Sequence Analysis, DNA/veterinary
- Trypanosoma congolense/genetics
- Ubiquinone/biosynthesis
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Affiliation(s)
- Waren N Baticados
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
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Witola WH, Sarataphan N, Inoue N, Ohashi K, Onuma M. Genetic variability in ESAG6 genes among Trypanosoma evansi isolates and in comparison to other Trypanozoon members. Acta Trop 2005; 93:63-73. [PMID: 15589799 DOI: 10.1016/j.actatropica.2004.09.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2004] [Revised: 08/12/2004] [Accepted: 09/14/2004] [Indexed: 11/15/2022]
Abstract
Bloodstream trypanosomes take up iron needed for their propagation through the transferrin receptor that, in Trypanosoma brucei, is encoded by expression-site-associated genes (ESAGs), ESAG6 and 7 genes located in variant surface glycoprotein expression sites. ESAG6 and 7 genes in different expression sites have been shown to encode transferrin receptors with varying affinities for polymorphic transferrins. T. brucei could cope with the different host transferrins by switching between expression sites. ESAG6- and 7-encoded transferrin receptor appear to be present in Trypanosoma evansi but the genes have not yet been characterized. In this study, we cloned and sequenced different members of ESAG6 genes in seven isolates of T. evansi from geographically distinct localities in Thailand. We assessed the intra- and inter-species genetic variability in the transferrin receptor gene regions involved in transferrin binding and established that T. evansi, like T. brucei, has widely diverse ESAG6 genes. In addition, T. evansi possess a clade of ESAG6 variants not observed in T. brucei and different T. evansi strains share at least two conserved variants. We further noted that T. evansi possesses all the reported T. equiperdum ESAG6 variants as a subset. Our findings depict a correlation between the genetic diversity in the transferrin-binding regions of ESAG6 genes with the broad host range of T. evansi and T. brucei compared to the narrow host range of Trypanosoma equiperdum.
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Affiliation(s)
- William H Witola
- Laboratory of Infectious Diseases, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
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Witola WH, Inoue N, Ohashi K, Onuma M. RNA-interference silencing of the adenosine transporter-1 gene in Trypanosoma evansi confers resistance to diminazene aceturate. Exp Parasitol 2004; 107:47-57. [PMID: 15208037 DOI: 10.1016/j.exppara.2004.03.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2003] [Revised: 01/15/2004] [Accepted: 03/30/2004] [Indexed: 11/16/2022]
Abstract
Drug resistance of trypanosomes is now a problem, but its underlying mechanisms are not fully understood. Cellular uptake of the major trypanocidal drugs is thought to occur through an adenosine transporter. The adenosine transporter-1 gene, TbAT1, encoding a P2-like nucleoside transporter has previously been cloned from Trypanosoma brucei brucei, and when expressed in yeast, it showed very similar substrate specificity to the P2-nucleoside transporter, but could not transport diamidines (pentamidine and diminazene). We have cloned and sequenced a similar gene (TevAT1) from Trypanosoma evansi and found it to have 99.7% identity to the TbAT1 gene. To elucidate the role of the TevAT1 gene on diamidine trypanocidal effect, we genetically engineered T. evansi for conditional knock-out of the TevAT1 gene by RNA interference (RNAi). Induction of the RNAi resulted in 10-fold depletion of TevAT1 mRNA, with concomitantly significant resistance to diminazene aceturate (berenil). The induced parasites propagated normally and attained peak cell density at an in vitro concentration of berenil, 5.5-fold higher than the IC(100) of the wild-type. TevAT1 knock-out had no effect on the trypanocidal activity of suramin and antrycide, but conferred some resistance to samorin. Our findings validate the significance of the TevAT1 adenosine transporter-1 gene in mediating the trypanocidal effect of diamidines in T. evansi. Further, we show for the first time that RNAi gene silencing in T. evansi can be induced using plasmids designed for T. brucei. We also demonstrate the usefulness of real-time PCR in rapidly quantifying mRNA levels in trypanosomes.
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Affiliation(s)
- William H Witola
- Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
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Abstract
Anaemia is the most prominent clinical sign of trypanosomosis in domestic animals but little is known about its pathogenesis. This work investigated erythrophagocytosis as the possible cause of anaemia. Pathogenic Trypanosoma congolense (IL3000) was intravenously inoculated into six goats at 3x10(6) trypanosomes per goat. Six other goats were maintained as controls. The infection was studied for 10 weeks and parasitaemia, packed cell volume (PCV) and serum protein levels were determined. The amount of erythrophagocytosis was determined from the amount of 51Cr-labelled red blood cells (RBCs) phagocytosed by self mononuclear cells (MNCs) in vitro and by microscopically counting phagocytosed RBCs on Giemsa stained smears of incubated mixtures of RBCs and self MNCs. The infection resulted in trypanosomosis with rapid progressive anaemia and mean peaks of parasitaemia of about 3x10(3)ml(-1). In infected goats, a significant (P<0.05) mean reduction in PCV (of 37-22%) was observed starting from about 20 days up to 56 days post-infection. Within this same phase, significant (P<0.05) differences in mean radioactivity counts of (51)Cr incorporated into MNCs were observed with infected goats' samples having counts 50% higher than the control goats' samples. Microscopically, the mean number of phagocytosed RBCs in infected goats' MNCs was noted to be 80% higher (P<0.05) than that of control goats. Appreciable increases (P<0.05) in mean serum globulin levels, from 3.5 to 4.7g/dl, were observed within 3 weeks of infection. The study showed that erythrophagocytosis is an important mechanism leading to anaemia in the pathophysiology of T. congolense infection in Zambian goats.
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Affiliation(s)
- W H Witola
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Zambia, PO Box 32379, 10101, Lusaka, Zambia.
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