1
|
Lenière AC, Vlandas A, Follet J. Treating cryptosporidiosis: A review on drug discovery strategies. Int J Parasitol Drugs Drug Resist 2024; 25:100542. [PMID: 38669849 PMCID: PMC11066572 DOI: 10.1016/j.ijpddr.2024.100542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 04/15/2024] [Accepted: 04/18/2024] [Indexed: 04/28/2024]
Abstract
Despite several decades of research on therapeutics, cryptosporidiosis remains a major concern for human and animal health. Even though this field of research to assess antiparasitic drug activity is highly active and competitive, only one molecule is authorized to be used in humans. However, this molecule was not efficacious in immunocompromised people and the lack of animal therapeutics remains a cause of concern. Indeed, the therapeutic arsenal needs to be developed for both humans and animals. Our work aims to clarify research strategies that historically were diffuse and poorly directed. This paper reviews in vitro and in vivo methodologies to assess the activity of future therapeutic compounds by screening drug libraries or through drug repurposing. It focuses on High Throughput Screening methodologies (HTS) and discusses the lack of knowledge of target mechanisms. In addition, an overview of several specific metabolic pathways and enzymatic activities used as targets against Cryptosporidium is provided. These metabolic processes include glycolytic pathways, fatty acid production, kinase activities, tRNA elaboration, nucleotide synthesis, gene expression and mRNA maturation. As a conclusion, we highlight emerging future strategies for screening natural compounds and assessing drug resistance issues.
Collapse
Affiliation(s)
- Anne-Charlotte Lenière
- University of Lille, CNRS, Centrale Lille, Junia, Université Polytechnique Hauts de France, UMR 8520, IEMN Institut d'Electronique de Microélectronique et de Nanotechnologie, F, 59000, Lille, France
| | - Alexis Vlandas
- University of Lille, CNRS, Centrale Lille, Junia, Université Polytechnique Hauts de France, UMR 8520, IEMN Institut d'Electronique de Microélectronique et de Nanotechnologie, F, 59000, Lille, France
| | - Jérôme Follet
- University of Lille, CNRS, Centrale Lille, Junia, Université Polytechnique Hauts de France, UMR 8520, IEMN Institut d'Electronique de Microélectronique et de Nanotechnologie, F, 59000, Lille, France.
| |
Collapse
|
2
|
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] [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.
Collapse
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
| |
Collapse
|
3
|
Ranasinghe S, Armson A, Lymbery AJ, Zahedi A, Ash A. Medicinal plants as a source of antiparasitics: an overview of experimental studies. Pathog Glob Health 2023; 117:535-553. [PMID: 36805662 PMCID: PMC10392325 DOI: 10.1080/20477724.2023.2179454] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
Despite advances in modern human and veterinary medicine, gastrointestinal (GI) parasitic infections remain a significant health issue worldwide, mainly in developing countries. Increasing evidence of the multi-drug resistance of these parasites and the side effects of currently available synthetic drugs have led to increased research on alternative medicines to treat parasitic infections. The exploration of potential botanical antiparasitics, which are inexpensive and abundant, may be a promising alternative in this context. This study summarizes the in vitro/in vivo antiparasitic efficacy of different medicinal plants and their components against GI parasites. Published literature from 1990-2020 was retrieved from Google Scholar, Web of Science, PubMed and Scopus. A total of 68 plant species belonging to 32 families have been evaluated as antiparasitic agents against GI parasites worldwide. The majority of studies (70%) were conducted in vitro. Most plants were from the Fabaceae family (53%, n = 18). Methanol (37%, n = 35) was the most used solvent. Leaf (22%, n = 16) was the most used plant part, followed by seed and rhizome (each 12%, n = 9). These studies suggest that herbal medicines hold a great scope for new drug discoveries against parasitic diseases and that the derivatives of these plants are useful structures for drug synthesis and bioactivity optimization.
Collapse
Affiliation(s)
- Sandamalie Ranasinghe
- Centre for Biosecurity and One Health, Harry Butler Institute, Murdoch University, Perth, Western Australia, Australia
| | - Anthony Armson
- Exercise Science and Chiropractic, College of Science, Health, Engineering and Education, Murdoch University, Perth, Western Australia, Australia
| | - Alan J. Lymbery
- Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Perth, Western Australia, Australia
| | - Alireza Zahedi
- Centre for Biosecurity and One Health, Harry Butler Institute, Murdoch University, Perth, Western Australia, Australia
| | - Amanda Ash
- Centre for Biosecurity and One Health, Harry Butler Institute, Murdoch University, Perth, Western Australia, Australia
| |
Collapse
|
4
|
Hanna JC, Corpas-Lopez V, Seizova S, Colon BL, Bacchetti R, Hall GMJ, Sands EM, Robinson L, Baragaña B, Wyllie S, Pawlowic MC. Mode of action studies confirm on-target engagement of lysyl-tRNA synthetase inhibitor and lead to new selection marker for Cryptosporidium. Front Cell Infect Microbiol 2023; 13:1236814. [PMID: 37600947 PMCID: PMC10436570 DOI: 10.3389/fcimb.2023.1236814] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 07/10/2023] [Indexed: 08/22/2023] Open
Abstract
Introduction Cryptosporidiosis is a leading cause of diarrheal-associated morbidity and mortality, predominantly affecting children under 5 years old in low-and-middle-income countries. There is no effective treatment and no vaccine. New therapeutics are emerging from drug discovery efforts. It is critical that mode of action studies are performed alongside drug discovery to ensure the best clinical outcomes. Unfortunately, technology to identify and validate drug targets for Cryptosporidium is severely lacking. Methods We used C. parvum lysyl-tRNA synthetase (CpKRS) and DDD01510706 as a target-compound pair to develop both chemical and genetic tools for mode of action studies for Cryptosporidium. We adapted thermal proteome profiling (TPP) for Cryptosporidium, an unbiased approach for target identification. Results Using TPP we identified the molecular target of DDD01510706 and confirm that it is CpKRS. Genetic tools confirm that CpKRS is expressed throughout the life cycle and that this target is essential for parasite survival. Parasites genetically modified to over-express CpKRS or parasites with a mutation at the compound-binding site are resistant to treatment with DDD01510706. We leveraged these mutations to generate a second drug selection marker for genetic modification of Cryptosporidium, KRSR. This second selection marker is interchangeable with the original selection marker, NeoR, and expands the range of reverse genetic approaches available to study parasite biology. Due to the sexual nature of the Cryptosporidium life cycle, parental strains containing different drug selection markers can be crossed in vivo. Discussion Selection with both drug markers produces highly efficient genetic crosses (>99% hybrid progeny), paving the way for forward genetics approaches in Cryptosporidium.
Collapse
Affiliation(s)
- Jack C. Hanna
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Victor Corpas-Lopez
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Simona Seizova
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Beatrice L. Colon
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Ross Bacchetti
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Grant M. J. Hall
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Emma M. Sands
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Lee Robinson
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Beatriz Baragaña
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
- Drug Discovery Unit, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Susan Wyllie
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Mattie C. Pawlowic
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| |
Collapse
|
5
|
Gilbert IH, Vinayak S, Striepen B, Manjunatha UH, Khalil IA, Van Voorhis WC. Safe and effective treatments are needed for cryptosporidiosis, a truly neglected tropical disease. BMJ Glob Health 2023; 8:e012540. [PMID: 37541693 PMCID: PMC10407372 DOI: 10.1136/bmjgh-2023-012540] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 06/25/2023] [Indexed: 08/06/2023] Open
Affiliation(s)
| | - Sumiti Vinayak
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Boris Striepen
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, USA
| | - Ujjini H Manjunatha
- Global Health, Novartis Institutes for BioMedical Research, Inc, Emeryville, California, USA
| | - Ibrahim A Khalil
- Department of Health, State of Washington, Seattle, Washington, USA
| | | |
Collapse
|
6
|
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] [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.
Collapse
|
7
|
Cheng P, Wang C, Zhang L, Fei C, Liu Y, Wang M, Zhang K, Wang X, Gu F, Xue F. Label-free quantitative proteomic analysis of ethanamizuril-resistant versus -sensitive strains of Eimeria tenella. Parasit Vectors 2022; 15:319. [PMID: 36076292 PMCID: PMC9454127 DOI: 10.1186/s13071-022-05412-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 07/23/2022] [Indexed: 11/18/2022] Open
Abstract
Background Avian coccidiosis is an important parasitic disease that has serious adverse effects on the global poultry industry. The extensive use of anticoccidial drugs has resulted in an increase in drug resistance. Ethanamizuril (EZL) is a novel triazine with high anticoccidial activity. Methods We compared oocyst production and sporulation between EZL-sensitive (S) and EZL-resistant Eimeria tenella strains (R10 and R200) and used label-free quantitative proteomics to identify differentially expressed proteins (DEPs) between these strains. Results We generated two EZL-resistant E. tenella strains: strain R10, which was induced using a constant dose of 10 mg EZL/kg poultry feed, and strain R200, which was generated by gradually increasing the EZL dosage to 200 mg EZL/kg poultry feed. With an increase in resistance, the total oocyst output decreased, but the percentage of sporulation did not change significantly. We identified a total of 7511 peptides and 1282 proteins, and found 152 DEPs in the R10 strain versus the S strain, 426 DEPs in the R200 strain versus the S strain and 494 DEPs in the R200 strain versus the R10 strain. When compared with the S strain, 86 DEPs were found to have consistent trends in both resistant strains. The DEPs were primarily involved in ATP and GTP binding, invasion, and membrane components. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses of the DEPs suggested that they are involved in transcription and translation processes. Protein–protein interaction network analysis of the 86 DEPs showed that 10 proteins were hubs in the functional interaction network (≥ 8 edges) and five of them were ribosomal proteins. Conclusions The results of the present study indicate that the resistance mechanisms of E. tenella against EZL might be related to the transcriptional and translational processes, especially in the factors that inhibit the growth of parasites. The DEPs found in this study provide new insights into the resistance mechanisms of E. tenella against EZL. Further research on these potential targets holds promise for new chemotherapeutic approaches for controlling E. tenella infections. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05412-6.
Collapse
Affiliation(s)
- Peipei Cheng
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs/Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Minhang District, Shanghai, 200241, China
| | - Chunmei Wang
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs/Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Minhang District, Shanghai, 200241, China.
| | - Lifang Zhang
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs/Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Minhang District, Shanghai, 200241, China
| | - Chenzhong Fei
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs/Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Minhang District, Shanghai, 200241, China
| | - Yingchun Liu
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs/Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Minhang District, Shanghai, 200241, China
| | - Mi Wang
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs/Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Minhang District, Shanghai, 200241, China
| | - Keyu Zhang
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs/Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Minhang District, Shanghai, 200241, China
| | - Xiaoyang Wang
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs/Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Minhang District, Shanghai, 200241, China
| | - Feng Gu
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs/Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Minhang District, Shanghai, 200241, China
| | - Feiqun Xue
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs/Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Minhang District, Shanghai, 200241, China.
| |
Collapse
|
8
|
Bone Relat RM, Winder PL, Bowden GD, Guzmán EA, Peterson TA, Pomponi SA, Roberts JC, Wright AE, O’Connor RM. High-Throughput Screening of a Marine Compound Library Identifies Anti-Cryptosporidium Activity of Leiodolide A. Mar Drugs 2022; 20:md20040240. [PMID: 35447913 PMCID: PMC9026894 DOI: 10.3390/md20040240] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/24/2022] [Accepted: 03/24/2022] [Indexed: 02/04/2023] Open
Abstract
Cryptosporidium sp. are apicomplexan parasites that cause significant morbidity and possible mortality in humans and valuable livestock. There are no drugs on the market that are effective in the population most severely affected by this parasite. This study is the first high-throughput screen for potent anti-Cryptosporidium natural products sourced from a unique marine compound library. The Harbor Branch Oceanographic Institute at Florida Atlantic University has a collection of diverse marine organisms some of which have been subjected to medium pressure liquid chromatography to create an enriched fraction library. Numerous active compounds have been discovered from this library, but it has not been tested against Cryptosporidium parvum. A high-throughput in vitro growth inhibition assay was used to test 3764 fractions in the library, leading to the identification of 23 fractions that potently inhibited the growth of Cryptosporidium parvum. Bioassay guided fractionation of active fractions from a deep-sea sponge, Leiodermatium sp., resulted in the purification of leiodolide A, the major active compound in the organism. Leiodolide A displayed specific anti-Cryptosporidium activity at a half maximal effective concentration of 103.5 nM with selectivity indexes (SI) of 45.1, 11.9, 19.6 and 14.3 for human ileocecal colorectal adenocarcinoma cells (HCT-8), human hepatocellular carcinoma cells (Hep G2), human neuroblastoma cells (SH-SY5Y) and green monkey kidney cells (Vero), respectively. The unique structure of leiodolide A provides a valuable drug scaffold on which to develop new anti-Cryptosporidium compounds and supports the importance of screening natural product libraries for new chemical scaffolds.
Collapse
Affiliation(s)
- Rachel M. Bone Relat
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, 100 Dairy Rd, Pullman, WA 99164, USA; (R.M.B.R.); (G.D.B.)
| | - Priscilla L. Winder
- Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 US Highway 1 North, Fort Pierce, FL 34946, USA; (P.L.W.); (E.A.G.); (T.A.P.); (S.A.P.); (J.C.R.)
| | - Gregory D. Bowden
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, 100 Dairy Rd, Pullman, WA 99164, USA; (R.M.B.R.); (G.D.B.)
| | - Esther A. Guzmán
- Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 US Highway 1 North, Fort Pierce, FL 34946, USA; (P.L.W.); (E.A.G.); (T.A.P.); (S.A.P.); (J.C.R.)
| | - Tara A. Peterson
- Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 US Highway 1 North, Fort Pierce, FL 34946, USA; (P.L.W.); (E.A.G.); (T.A.P.); (S.A.P.); (J.C.R.)
| | - Shirley A. Pomponi
- Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 US Highway 1 North, Fort Pierce, FL 34946, USA; (P.L.W.); (E.A.G.); (T.A.P.); (S.A.P.); (J.C.R.)
| | - Jill C. Roberts
- Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 US Highway 1 North, Fort Pierce, FL 34946, USA; (P.L.W.); (E.A.G.); (T.A.P.); (S.A.P.); (J.C.R.)
| | - Amy E. Wright
- Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 US Highway 1 North, Fort Pierce, FL 34946, USA; (P.L.W.); (E.A.G.); (T.A.P.); (S.A.P.); (J.C.R.)
- Correspondence: (A.E.W.); (R.M.O.)
| | - Roberta M. O’Connor
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, 100 Dairy Rd, Pullman, WA 99164, USA; (R.M.B.R.); (G.D.B.)
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, 1971 Commonwealth Ave, St Paul, MN 55108, USA
- Correspondence: (A.E.W.); (R.M.O.)
| |
Collapse
|
9
|
Abstract
PURPOSE OF REVIEW Substantial progress has been made recently on the development of new therapeutics for cryptosporidiosis, an infection by the protozoan parasite Cryptosporidium that is associated with diarrhea, malnutrition, growth stunting, cognitive deficits, and oral vaccine failure in children living in low-resource settings. RECENT FINDINGS Various drug discovery approaches have generated promising lead candidates. The repurposed antimycobacterial drug clofazimine was tested in Malawian HIV patients with cryptosporidiosis but was ineffective. Target-based screens identified inhibitors of lysyl-tRNA synthetase, phenylalanyl-tRNA synthetase, methionyl-tRNA synthetase, and calcium-dependent protein kinase 1. Phenotypic screens led to discovery of a phosphatidylinositol 4-kinase inhibitor, the piperazine MMV665917, and the benzoxaborole AN7973. The relationship between pharmacokinetic properties and in-vivo efficacy is gradually emerging. A pathway to clinical trials, regulatory approval, and introduction has been proposed but additional work is needed to strengthen the route. SUMMARY Several lead compounds with potent activity in animal models and a favorable safety profile have been identified. A sustained effort will be required to advance at least one to clinical proof-of-concept studies. The demonstrated risk of resistance indicates multiple candidates should be advanced as potential components of a combination therapy.
Collapse
Affiliation(s)
- Melissa S. Love
- Calibr, a division of The Scripps Research Institute, La Jolla, California, USA
| | | |
Collapse
|
10
|
Opportunities and Challenges in Developing a Cryptosporidium Controlled Human Infection Model for Testing Antiparasitic Agents. ACS Infect Dis 2021; 7:959-968. [PMID: 33822577 PMCID: PMC8154424 DOI: 10.1021/acsinfecdis.1c00057] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cryptosporidiosis is a leading cause of moderate-to-severe diarrhea in low- and middle-income countries, responsible for high mortality in children younger than two years of age, and it is also strongly associated with childhood malnutrition and growth stunting. There is no vaccine for cryptosporidiosis and existing therapeutic options are suboptimal to prevent morbidity and mortality in young children. Recently, novel therapeutic agents have been discovered through high-throughput phenotypic and target-based screening strategies, repurposing malaria hits, etc., and these agents have a promising preclinical in vitro and in vivo anti-Cryptosporidium efficacy. One key step in bringing safe and effective new therapies to young vulnerable children is the establishment of some prospect of direct benefit before initiating pediatric clinical studies. A Cryptosporidium controlled human infection model (CHIM) in healthy adult volunteers can be a robust clinical proof of concept model for evaluating novel therapeutics. CHIM could potentially accelerate the development path to pediatric studies by establishing the safety of a proposed pediatric dosing regimen and documenting preliminary efficacy in adults. We present, here, perspectives regarding the opportunities and perceived challenges with the Cryptosporidium human challenge model.
Collapse
|