1
|
Madhav H, Reddy GS, Rizvi Z, Jameel E, Patel TS, Rahman A, Yadav V, Fatima S, Heyat F, Pal K, Minju-Op A, Subbarao N, Bhattacharjee S, Dixit BC, Sijwali PS, Hoda N. Reinvestigation of diphenylmethylpiperazine analogues of pyrazine as new class of Plasmodial cysteine protease inhibitors for the treatment of malaria. RSC Med Chem 2024; 15:1022-1037. [PMID: 38516592 PMCID: PMC10953474 DOI: 10.1039/d3md00490b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 12/19/2023] [Indexed: 03/23/2024] Open
Abstract
Malaria eradication is still a global challenge due to the lack of a broadly effective vaccine and the emergence of drug resistance to most of the currently available drugs as part of the mainline artemisinin-based combination therapy. A variety of experimental approaches are quite successful in identifying and synthesizing new promising pharmacophore hybrids with distinct mechanisms of action. Based on our recent findings, the current study demonstrates the reinvestigation of a series of diphenylmethylpiperazine and pyrazine-derived molecular hybrids. Pyrazine-derived molecular hybrids were screened to investigate the antiplasmodial activity on drug-susceptible Pf3D7 and drug-resistant PfW2 strains. The selected compounds were shown to be potent dual inhibitors of cysteine protease PfFP2 and PfFP3. Time-course parasitic development study demonstrated that compounds were able to arrest the growth of the parasite at the early trophozoite stage. The compounds did not show hemolysis of red blood cells and showed selectivity to the parasite compared with the mammalian Vero and A5489 cell lines. The study underlined HR5 and HR15 as a new class of Plasmodial falcipain inhibitors with an IC50 of 6.2 μM and 5.9 μM for PfFP2 and 6.8 μM and 6.4 μM for PfFP3, respectively. Both compounds have antimalarial efficacy with IC50 values of 3.05 μM and 2.80 μM for the Pf3D7 strain, and 4.35 μM and 3.39 μM for the PfW2 strain, respectively. Further structural optimization may turn them into potential Plasmodial falcipain inhibitors for malaria therapeutics.
Collapse
Affiliation(s)
- Hari Madhav
- Drug Design and Synthesis Laboratory, Department of Chemistry, Jamia Millia Islamia (A Central University) New Delhi-110025 India
| | - G Srinivas Reddy
- CSIR-Centre for Cellular and Molecular Biology Hyderabad-500007 TS India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad-201002 UP India
| | - Zeba Rizvi
- CSIR-Centre for Cellular and Molecular Biology Hyderabad-500007 TS India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad-201002 UP India
| | - Ehtesham Jameel
- Drug Design and Synthesis Laboratory, Department of Chemistry, Jamia Millia Islamia (A Central University) New Delhi-110025 India
| | - Tarosh S Patel
- Chemistry Department, V. P. & R. P. T. P Science College, Affiliated to Sardar Patel University Vallabh Vidyanagar-388120 Gujarat India
| | - Abdur Rahman
- Special Centre for Molecular Medicine, Jawaharlal Nehru University New Delhi-110067 India
| | - Vikas Yadav
- School of Computational and Integrative Sciences, Jawaharlal Nehru University New Delhi-110067 India
| | - Sadaf Fatima
- Drug Design and Synthesis Laboratory, Department of Chemistry, Jamia Millia Islamia (A Central University) New Delhi-110025 India
| | - Fatima Heyat
- Drug Design and Synthesis Laboratory, Department of Chemistry, Jamia Millia Islamia (A Central University) New Delhi-110025 India
| | - Kavita Pal
- Drug Design and Synthesis Laboratory, Department of Chemistry, Jamia Millia Islamia (A Central University) New Delhi-110025 India
| | - Amisha Minju-Op
- CSIR-Centre for Cellular and Molecular Biology Hyderabad-500007 TS India
| | - Naidu Subbarao
- School of Computational and Integrative Sciences, Jawaharlal Nehru University New Delhi-110067 India
| | - Souvik Bhattacharjee
- Special Centre for Molecular Medicine, Jawaharlal Nehru University New Delhi-110067 India
| | - Bharat C Dixit
- CSIR-Centre for Cellular and Molecular Biology Hyderabad-500007 TS India
| | - Puran Singh Sijwali
- CSIR-Centre for Cellular and Molecular Biology Hyderabad-500007 TS India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad-201002 UP India
| | - Nasimul Hoda
- Drug Design and Synthesis Laboratory, Department of Chemistry, Jamia Millia Islamia (A Central University) New Delhi-110025 India
| |
Collapse
|
2
|
Uddin A, Gupta S, Shoaib R, Aneja B, Irfan I, Gupta K, Rawat N, Combrinck J, Kumar B, Aleem M, Hasan P, Joshi MC, Chhonker YS, Zahid M, Hussain A, Pandey K, Alajmi MF, Murry DJ, Egan TJ, Singh S, Abid M. Blood-stage antimalarial activity, favourable metabolic stability and in vivo toxicity of novel piperazine linked 7-chloroquinoline-triazole conjugates. Eur J Med Chem 2024; 264:115969. [PMID: 38039787 DOI: 10.1016/j.ejmech.2023.115969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 11/14/2023] [Accepted: 11/15/2023] [Indexed: 12/03/2023]
Abstract
The persistence of drug resistance poses a significant obstacle to the advancement of efficacious malaria treatments. The remarkable efficacy displayed by 1,2,3-triazole-based compounds against Plasmodium falciparum highlights the potential of triazole conjugates, with diverse pharmacologically active structures, as potential antimalarial agents. We aimed to synthesize 7-dichloroquinoline-triazole conjugates and their structure-activity relationship (SAR) derivatives to investigate their anti-plasmodial activity. Among them, QP11, featuring a m-NO2 substitution, demonstrated efficacy against both chloroquine-sensitive and -resistant parasite strains. QP11 selectively inhibited FP2, a cysteine protease involved in hemoglobin degradation, and showed synergistic effects when combined with chloroquine. Additionally, QP11 hindered hemoglobin degradation and hemozoin formation within the parasite. Metabolic stability studies indicated high stability of QP11, making it a promising antimalarial candidate. In vivo evaluation using a murine malaria model demonstrated QP11's efficacy in eradicating parasite growth without neurotoxicity, presenting it as a promising compound for novel antimalarial development.
Collapse
Affiliation(s)
- Amad Uddin
- Medicinal Chemistry Laboratory, Department of Biosciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India; Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Sonal Gupta
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Rumaisha Shoaib
- Medicinal Chemistry Laboratory, Department of Biosciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India; Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Babita Aneja
- Medicinal Chemistry Laboratory, Department of Biosciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India
| | - Iram Irfan
- Medicinal Chemistry Laboratory, Department of Biosciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India
| | - Kanika Gupta
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Neha Rawat
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Jill Combrinck
- Department of Chemistry, University of Cape Town, Private Bag, Rondebosch, Cape Town, 7701, South Africa
| | - Bhumika Kumar
- Medicinal Chemistry Laboratory, Department of Biosciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India; National Institute of Malaria Research, New Delhi, 110077, India
| | - Mohd Aleem
- Division of Behavioral Neuroscience, Institute of Nuclear Medicine and Allied Sciences, Delhi, 110054, India
| | - Phool Hasan
- Medicinal Chemistry Laboratory, Department of Biosciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India
| | - Mukesh C Joshi
- Department of Chemistry, Kirori Mal College, University of Delhi, Delhi, 110007, India
| | - Yashpal S Chhonker
- Department of Pharmacy Practice and Science College of Pharmacy, University of Nebraska Medical Center, 986145, Nebraska Medical Center, Omaha, NE, 68198-6145, USA
| | - Muhammad Zahid
- Department of Environmental, Agricultural and Occupational Health, University of Nebraska Medical Center, 986145, Nebraska Medical Center, Omaha, NE, 68198-6145, USA
| | - Afzal Hussain
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Kailash Pandey
- National Institute of Malaria Research, New Delhi, 110077, India
| | - Mohamed F Alajmi
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Daryl J Murry
- Department of Pharmacy Practice and Science College of Pharmacy, University of Nebraska Medical Center, 986145, Nebraska Medical Center, Omaha, NE, 68198-6145, USA
| | - Timothy J Egan
- Department of Chemistry, University of Cape Town, Private Bag, Rondebosch, Cape Town, 7701, South Africa
| | - Shailja Singh
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India.
| | - Mohammad Abid
- Medicinal Chemistry Laboratory, Department of Biosciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India.
| |
Collapse
|
3
|
González JEH, Salas-Sarduy E, Alvarez LH, Valiente PA, Arni RK, Pascutti PG. Three Decades of Targeting Falcipains to Develop Antiplasmodial Agents: What have we Learned and What can be Done Next? Curr Med Chem 2024; 31:2234-2263. [PMID: 37711130 DOI: 10.2174/0929867331666230913165219] [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: 03/28/2023] [Revised: 05/06/2023] [Accepted: 07/25/2023] [Indexed: 09/16/2023]
Abstract
Malaria is a devastating infectious disease that affects large swathes of human populations across the planet's tropical regions. It is caused by parasites of the genus Plasmodium, with Plasmodium falciparum being responsible for the most lethal form of the disease. During the intraerythrocytic stage in the human hosts, malaria parasites multiply and degrade hemoglobin (Hb) using a battery of proteases, which include two cysteine proteases, falcipains 2 and 3 (FP-2 and FP-3). Due to their role as major hemoglobinases, FP-2 and FP-3 have been targeted in studies aiming to discover new antimalarials and numerous inhibitors with activity against these enzymes, and parasites in culture have been identified. Nonetheless, cross-inhibition of human cysteine cathepsins remains a serious hurdle to overcome for these compounds to be used clinically. In this article, we have reviewed key functional and structural properties of FP-2/3 and described different compound series reported as inhibitors of these proteases during decades of active research in the field. Special attention is also paid to the wide range of computer-aided drug design (CADD) techniques successfully applied to discover new active compounds. Finally, we provide guidelines that, in our understanding, will help advance the rational discovery of new FP-2/3 inhibitors.
Collapse
Affiliation(s)
- Jorge Enrique Hernández González
- Multiuser Center for Biomolecular Innovation, IBILCE/UNESP, São José do Rio Preto, SP, Brazil
- Department of Pharmaceutical Sciences, UZA II, University of Vienna, Vienna, 1090, Austria
| | - Emir Salas-Sarduy
- Instituto de Investigaciones Biotecnológicas Dr. Rodolfo Ugalde, Universidad Nacional de San Martín, CONICET, San Martín, Buenos Aires, Argentina
- Escuela de Bio y Nanotecnología (EByN), Universidad de San Martín (UNSAM), San Martín, Buenos Aires, Argentina
| | | | - Pedro Alberto Valiente
- Donnelly Centre for Cellular & Biomolecular Research, University of Toronto, Toronto, Canada
| | | | - Pedro Geraldo Pascutti
- Laboratório de Modelagem e Dinâmica Molecular, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, RJ, Brazil
| |
Collapse
|
4
|
Madhav H, Patel TS, Rizvi Z, Reddy GS, Rahman A, Rahman MA, Ahmedi S, Fatima S, Saxena K, Manzoor N, Bhattacharjee S, Dixit BC, Sijwali PS, Hoda N. Development of diphenylmethylpiperazine hybrids of chloroquinoline and triazolopyrimidine using Petasis reaction as new cysteine proteases inhibitors for malaria therapeutics. Eur J Med Chem 2023; 258:115564. [PMID: 37321109 DOI: 10.1016/j.ejmech.2023.115564] [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: 05/14/2023] [Revised: 06/08/2023] [Accepted: 06/10/2023] [Indexed: 06/17/2023]
Abstract
Malaria is a widespread infectious disease, causing nearly 247 million cases in 2021. The absence of a broadly effective vaccine and rapidly decreasing effectiveness of most of the currently used antimalarials are the major challenges to malaria eradication efforts. To design and develop novel antimalarials, we synthesized a series of 4,7-dichloroquinoline and methyltriazolopyrimidine analogues using a multi-component Petasis reaction. The synthesized molecules (11-31) were screened for in-vitro antimalarial activity against drug-sensitive and drug-resistant strains of Plasmodium falciparum with an IC50 value of 0.53 μM. The selected compounds were screened to evaluate in-vitro and in-silico enzyme inhibition efficacy against two cysteine proteases, PfFP2 and PfFP3. The compounds 15 and 17 inhibited PfFP2 with an IC50 = 3.5 and 4.8 μM, respectively and PfFP3 with an IC50 = 4.9 and 4.7 μM, respectively. Compounds 15 and 17 were found equipotent against the Pf3D7 strain with an IC50 value of 0.74 μM, whereas both were displayed IC50 values of 1.05 μM and 1.24 μM for the PfW2 strain, respectively. Investigation of effect of compounds on parasite development demonstrated that compounds were able to arrest the growth of the parasites at trophozoite stage. The selected compounds were screened for in-vitro cytotoxicity against mammalian lines and human red-blood-cell (RBC), which demonstrated no significant cytotoxicity associated with the molecules. In addition, in silico ADME prediction and physiochemical properties supported the drug-likeness of the synthesized molecules. Thus, the results highlighted the diphenylmethylpiperazine group cast on 4,7-dichloroquinoline and methyltriazolopyrimidine using Petasis reaction may serve as models for the development of new antimalarial agents.
Collapse
Affiliation(s)
- Hari Madhav
- Drug Design and Synthesis Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi, 110025, India
| | - Tarosh S Patel
- Chemistry Department, V. P. & R. P. T. P Science College, Affiliated to Sardar Patel University, Vallabh Vidyanagar, 388 120, Gujarat, India
| | - Zeba Rizvi
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, 500007, TS, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, UP, India
| | - G Srinivas Reddy
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, 500007, TS, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, UP, India
| | - Abdur Rahman
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Md Ataur Rahman
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Saiema Ahmedi
- Medical Mycology Lab, Department of Biosciences, Jamia Millia Islamia, New Delhi, 110025, India
| | - Sadaf Fatima
- Drug Design and Synthesis Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi, 110025, India
| | - Kanika Saxena
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, 500007, TS, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, UP, India
| | - Nikhat Manzoor
- Medical Mycology Lab, Department of Biosciences, Jamia Millia Islamia, New Delhi, 110025, India
| | - Souvik Bhattacharjee
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Bharat C Dixit
- Chemistry Department, V. P. & R. P. T. P Science College, Affiliated to Sardar Patel University, Vallabh Vidyanagar, 388 120, Gujarat, India
| | - Puran Singh Sijwali
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, 500007, TS, India.
| | - Nasimul Hoda
- Drug Design and Synthesis Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi, 110025, India.
| |
Collapse
|
5
|
Ong JJY, Oh J, Yong Ang X, Naidu R, Chu TTT, Hyoung Im J, Manzoor U, Kha Nguyen T, Na SW, Han ET, Davis C, Sun Park W, Chun W, Jun H, Jin Lee S, Na S, Chan JKY, Park Y, Russell B, Chandramohanadas R, Han JH. Optical diffraction tomography and image reconstruction to measure host cell alterations caused by divergent Plasmodium species. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 286:122026. [PMID: 36395614 DOI: 10.1016/j.saa.2022.122026] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/29/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
Malaria is a life-threatening infectious disease caused by parasites of the genus Plasmodium. Understanding the biological features of various parasite forms is important for the optical diagnosis and defining pathological states, which are often constrained by the lack of ambient visualization approaches. Here, we employ a label-free tomographic technique to visualize the host red blood cell (RBC) remodeling process and quantify changes in biochemical properties arising from parasitization. Through this, we provide a quantitative body of information pertaining to the influence of host cell environment on growth, survival, and replication of P. falciparum and P. vivax in their respective host cells: mature erythrocytes and young reticulocytes. These exquisite three-dimensional measurements of infected red cells demonstrats the potential of evolving 3D imaging to advance our understanding of Plasmodium biology and host-parasite interactions.
Collapse
Affiliation(s)
- Jessica J Y Ong
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
| | - Jeonghun Oh
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea; KAIST Institute for Health Science and Technology, KAIST, Daejeon 34141, Republic of Korea
| | - Xiang Yong Ang
- Department of Microbiology and Immunology, National University of Singapore, Singapore
| | - Renugah Naidu
- Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore, Singapore
| | - Trang T T Chu
- Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore, Singapore
| | - Jae Hyoung Im
- Department of Infectious Disease, Inha University School of Medicine, Incheon 22212, Republic of Korea
| | - Umar Manzoor
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Tuyet Kha Nguyen
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Seok-Won Na
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Christeen Davis
- DBT Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India; Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
| | - Won Sun Park
- Department of Physiology, School of Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Wanjoo Chun
- Department of Pharmacology, School of Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Hojong Jun
- Department of Tropical Medicine, Inha University College of Medicine, Incheon 22212, Republic of Korea
| | - Se Jin Lee
- Department of Obstetrics and Gynecology, Kangwon National University Hospital, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Sunghun Na
- Department of Obstetrics and Gynecology, Kangwon National University Hospital, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Jerry K Y Chan
- KK Womens' and Childrens' Hospital, Singapore; Academic Clinical Program in Obstetrics and Gynaecology, Duke-NUS Medical School, 169857, Singapore
| | - YongKeun Park
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea; KAIST Institute for Health Science and Technology, KAIST, Daejeon 34141, Republic of Korea; Tomocube Inc, Daejeon 34109, Republic of Korea
| | - Bruce Russell
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
| | - Rajesh Chandramohanadas
- Department of Microbiology and Immunology, National University of Singapore, Singapore; Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore, Singapore; DBT Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India.
| | - Jin-Hee Han
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand; Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea.
| |
Collapse
|
6
|
Lê HG, Kang JM, Võ TC, Yoo WG, Lee KH, Na BK. Biochemical Properties of Two Plasmodium malariae Cysteine Proteases, Malapain-2 and Malapain-4. Microorganisms 2022; 10:microorganisms10010193. [PMID: 35056641 PMCID: PMC8780100 DOI: 10.3390/microorganisms10010193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Revised: 01/12/2022] [Accepted: 01/13/2022] [Indexed: 11/25/2022] Open
Abstract
Cysteine proteases belonging to the falcipain (FP) family play a pivotal role in the biology of malaria parasites and have been extensively investigated as potential antimalarial drug targets. Three paralogous FP-family cysteine proteases of Plasmodium malariae, termed malapains 2–4 (MP2–4), were identified in PlasmoDB. The three MPs share similar structural properties with the FP-2/FP-3 subfamily enzymes and exhibit a close phylogenetic lineage with vivapains (VXs) and knowpains (KPs), FP orthologues of P. vivax and P. knowlesi. Recombinant MP-2 and MP-4 were produced in a bacterial expression system, and their biochemical properties were characterized. Both recombinant MP-2 and MP-4 showed enzyme activity across a broad range of pH values with an optimum activity at pH 5.0 and relative stability at neutral pHs. Similar to the FP-2/FP-3 subfamily enzymes in other Plasmodium species, recombinant MP-2 and MP-4 effectively hydrolyzed hemoglobin at acidic pHs. They also degraded erythrocyte cytoskeletal proteins, such as spectrin and band 3, at a neutral pH. These results imply that MP-2 and MP-4 are redundant hemoglobinases of P. malariae and may also participate in merozoite egression by degrading erythrocyte cytoskeletal proteins. However, compared with other FP-2/FP-3 enzymes, MP-2 showed a strong preference for arginine at the P2 position. Meanwhile, MP-4 showed a primary preference for leucine at the P2 position but a partial preference for phenylalanine. These different substrate preferences of MPs underscore careful consideration in the design of optimized inhibitors targeting the FP-family cysteine proteases of human malaria parasites.
Collapse
Affiliation(s)
- Hương Giang Lê
- Department of Parasitology and Tropical Medicine, Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Korea
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea
| | - Jung-Mi Kang
- Department of Parasitology and Tropical Medicine, Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Korea
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea
| | - Tuấn Cường Võ
- Department of Parasitology and Tropical Medicine, Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Korea
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea
| | - Won Gi Yoo
- Department of Parasitology and Tropical Medicine, Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Korea
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea
| | - Kon Ho Lee
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea
- Department of Microbiology, Gyeongsang National University College of Medicine, Jinju 52727, Korea
| | - Byoung-Kuk Na
- Department of Parasitology and Tropical Medicine, Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Korea
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea
| |
Collapse
|
7
|
Singh V, Hada RS, Uddin A, Aneja B, Abid M, Pandey KC, Singh S. Inhibition of Hemoglobin Degrading Protease Falcipain-2 as a Mechanism for Anti-Malarial Activity of Triazole-Amino Acid Hybrids. Curr Top Med Chem 2020; 20:377-389. [PMID: 32000644 DOI: 10.2174/1568026620666200130162347] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/20/2019] [Accepted: 10/20/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND Novel drug development against malaria parasite over old conventional antimalarial drugs is essential due to rapid and indiscriminate use of drugs, which led to the emergence of resistant strains. METHODS In this study, previously reported triazole-amino acid hybrids (13-18) are explored against Plasmodium falciparum as antimalarial agents. Among six compounds, 15 and 18 exhibited antimalarial activity against P. falciparum with insignificant hemolytic activity and cytotoxicity towards HepG2 mammalian cells. In molecular docking studies, both compounds bind into the active site of PfFP-2 and block its accessibility to the substrate that leads to the inhibition of target protein further supported by in vitro analysis. RESULTS Antimalarial half-maximal inhibitory concentration (IC50) of 15 and 18 compounds were found to be 9.26 μM and 20.62 μM, respectively. Blood stage specific studies showed that compounds, 15 and 18 are effective at late trophozoite stage and block egress pathway of parasites. Decreased level of free monomeric heme was found in a dose dependent manner after the treatment with compounds 15 and 18, which was further evidenced by the reduction in percent of hemoglobin hydrolysis. Compounds 15 and 18 hindered hemoglobin degradation via intra- and extracellular cysteine protease falcipain-2 (PfFP-2) inhibitory activity both in in vitro and in vivo in P. falciparum. CONCLUSION We report antimalarial potential of triazole-amino acid hybrids and their role in the inhibition of cysteine protease PfFP-2 as its mechanistic aspect.
Collapse
Affiliation(s)
- Vigyasa Singh
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Rahul Singh Hada
- Department of Life Sciences, Shiv Nadar University, Gautam Buddha Nagar UP, 201314, India
| | - Amad Uddin
- Medicinal Chemistry Laboratory, Department of Biosciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India
| | - Babita Aneja
- Medicinal Chemistry Laboratory, Department of Biosciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India.,Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Mohammad Abid
- Medicinal Chemistry Laboratory, Department of Biosciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India
| | - Kailash C Pandey
- Host-Parasite Interaction Biology Group, National Institute of Malaria Research, Indian Council of Medical Research, Sector-8, Dwarka, New Delhi 110077, India
| | - Shailja Singh
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| |
Collapse
|
8
|
Huang G, Murillo Solano C, Melendez J, Shaw J, Collins J, Banks R, Arshadi AK, Boonhok R, Min H, Miao J, Chakrabarti D, Yuan Y. Synthesis, Structure-Activity Relationship, and Antimalarial Efficacy of 6-Chloro-2-arylvinylquinolines. J Med Chem 2020; 63:11756-11785. [PMID: 32959656 DOI: 10.1021/acs.jmedchem.0c00858] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
There is an urgent need to develop new efficacious antimalarials to address the emerging drug-resistant clinical cases. Our previous phenotypic screening identified styrylquinoline UCF501 as a promising antimalarial compound. To optimize UCF501, we herein report a detailed structure-activity relationship study of 2-arylvinylquinolines, leading to the discovery of potent, low nanomolar antiplasmodial compounds against a Plasmodium falciparum CQ-resistant Dd2 strain, with excellent selectivity profiles (resistance index < 1 and selectivity index > 200). Several metabolically stable 2-arylvinylquinolines are identified as fast-acting agents that kill asexual blood-stage parasites at the trophozoite phase, and the most promising compound 24 also demonstrates transmission blocking potential. Additionally, the monophosphate salt of 24 exhibits excellent in vivo antimalarial efficacy in the murine model without noticeable toxicity. Thus, the 2-arylvinylquinolines represent a promising class of antimalarial drug leads.
Collapse
Affiliation(s)
- Guang Huang
- Department of Chemistry, University of Central Florida, Orlando, Florida 32816, United States
| | - Claribel Murillo Solano
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida 32826, United States
| | - Joel Melendez
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida 32826, United States
| | - Justin Shaw
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida 32826, United States
| | - Jennifer Collins
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida 32826, United States
| | - Robert Banks
- Research Program Services, University of Central Florida, Orlando, Florida 32816, United States
| | - Arash Keshavarzi Arshadi
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida 32826, United States
| | - Rachasak Boonhok
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, United States.,Department of Medical Technology, School of Allied Health Science, Walailak University, Nakhon Si Thammarat 80160, Thailand
| | - Hui Min
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, United States
| | - Jun Miao
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, United States
| | - Debopam Chakrabarti
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida 32826, United States
| | - Yu Yuan
- Department of Chemistry, University of Central Florida, Orlando, Florida 32816, United States
| |
Collapse
|
9
|
Huang G, Solano CM, Melendez J, Yu-Alfonzo S, Boonhok R, Min H, Miao J, Chakrabarti D, Yuan Y. Discovery of fast-acting dual-stage antimalarial agents by profiling pyridylvinylquinoline chemical space via copper catalyzed azide-alkyne cycloadditions. Eur J Med Chem 2020; 209:112889. [PMID: 33045660 DOI: 10.1016/j.ejmech.2020.112889] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 09/08/2020] [Accepted: 09/24/2020] [Indexed: 11/18/2022]
Abstract
To identity fast-acting, multistage antimalarial agents, a series of pyridylvinylquinoline-triazole analogues have been synthesized via CuAAC. Most of the compounds display significant inhibitory effect on the drug-resistant malarial Dd2 strain at low submicromolar concentrations. Among the tested analogues, compound 60 is the most potent molecule with an EC50 value of 0.04 ± 0.01 μM. Our current study indicates that compound 60 is a fast-acting antimalarial compound and it demonstrates stage specific action at the trophozoite phase in the P. falciparum asexual life cycle. In addition, compound 60 is active against both early and late stage P. falciparum gametocytes. From a mechanistic perspective, compound 60 shows good activity as an inhibitor of β-hematin formation. Collectively, our findings suggest that fast-acting agent 60 targets dual life stages of the malarial parasites and warrant further investigation of pyridylvinylquinoline hybrids as new antimalarials.
Collapse
Affiliation(s)
- Guang Huang
- Department of Chemistry, University of Central Florida, Orlando, FL, 32816, USA
| | - Claribel Murillo Solano
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, 32826, USA
| | - Joel Melendez
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, 32826, USA
| | - Sabrina Yu-Alfonzo
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, 32826, USA
| | - Rachasak Boonhok
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA; Department of Medical Technology, School of Allied Health Science, Walailak University, Nakhon Si Thammarat, 80160, Thailand
| | - Hui Min
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Jun Miao
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Debopam Chakrabarti
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, 32826, USA.
| | - Yu Yuan
- Department of Chemistry, University of Central Florida, Orlando, FL, 32816, USA.
| |
Collapse
|
10
|
Rosenthal PJ. Falcipain cysteine proteases of malaria parasites: An update. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140362. [DOI: 10.1016/j.bbapap.2020.140362] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/04/2020] [Accepted: 01/07/2020] [Indexed: 02/06/2023]
|
11
|
Identification of antimalarial leads with dual falcipain-2 and falcipain-3 inhibitory activity. Bioorg Med Chem 2020; 28:115155. [DOI: 10.1016/j.bmc.2019.115155] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 09/26/2019] [Accepted: 10/03/2019] [Indexed: 12/17/2022]
|
12
|
Mishra M, Singh V, Singh S. Structural Insights Into Key Plasmodium Proteases as Therapeutic Drug Targets. Front Microbiol 2019; 10:394. [PMID: 30891019 PMCID: PMC6411711 DOI: 10.3389/fmicb.2019.00394] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 02/14/2019] [Indexed: 11/13/2022] Open
Abstract
Malaria, caused by protozoan of genus Plasmodium, remains one of the highest mortality infectious diseases. Malaria parasites have a complex life cycle, easily adapt to their host’s immune system and have evolved with an arsenal of unique proteases which play crucial roles in proliferation and survival within the host cells. Owing to the existing knowledge of enzymatic mechanisms, 3D structures and active sites of proteases, they have been proven to be opportune for target based drug development. Here, we discuss in depth the crucial roles of essential proteases in Plasmodium life cycle and particularly focus on highlighting the atypical “structural signatures” of key parasite proteases which have been exploited for drug development. These features, on one hand aid parasites pathogenicity while on the other hand could be effective in designing targeted and very specific inhibitors for counteracting them. We conclude that Plasmodium proteases are suitable as multistage targets for designing novel drugs with new modes of action to combat malaria.
Collapse
Affiliation(s)
- Manasi Mishra
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Dadri, India
| | - Vigyasa Singh
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Shailja Singh
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Dadri, India.,Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| |
Collapse
|
13
|
Crucial residues in falcipains that mediate hemoglobin hydrolysis. Exp Parasitol 2019; 197:43-50. [PMID: 30648557 DOI: 10.1016/j.exppara.2019.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 11/03/2018] [Accepted: 01/11/2019] [Indexed: 02/08/2023]
|
14
|
Fernández-Boo S, Villalba A, Cao A. Variable protein profiles in extracellular products of the protistan parasite Perkinsus olseni among regions of the Spanish coast. J Invertebr Pathol 2015; 132:233-241. [DOI: 10.1016/j.jip.2015.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 11/02/2015] [Accepted: 11/06/2015] [Indexed: 10/22/2022]
|
15
|
Dalal S, Klemba M. Amino acid efflux by asexual blood-stage Plasmodium falciparum and its utility in interrogating the kinetics of hemoglobin endocytosis and catabolism in vivo. Mol Biochem Parasitol 2015. [PMID: 26215764 DOI: 10.1016/j.molbiopara.2015.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The endocytosis and catabolism of large quantities of host cell hemoglobin is a hallmark of the intraerythrocytic asexual stage of the human malaria parasite Plasmodium falciparum. It is known that the parasite's production of amino acids from hemoglobin far exceeds its metabolic needs. Here, we show that P. falciparum effluxes large quantities of certain non-polar (Ala, Leu, Val, Pro, Phe, Gly) and polar (Ser, Thr, His) amino acids to the external medium. That these amino acids originate from hemoglobin catabolism is indicated by the strong correlation between individual amino acid efflux rates and their abundances in hemoglobin, and the ability of the food vacuole falcipain inhibitor E-64d to greatly suppress efflux rates. We then developed a rapid, sensitive and precise method for quantifying flux through the hemoglobin endocytic-catabolic pathway that is based on leucine efflux. Optimization of the method involved the generation of a novel amino acid-restricted RPMI formulation as well as the validation of D-norvaline as an internal standard. The utility of this method was demonstrated by characterizing the effects of the phosphatidylinositol-3-kinase inhibitors wortmannin and dihydroartemisinin on the kinetics of Leu efflux. Both compounds rapidly inhibited Leu efflux, which is consistent with a role for phosphtidylinositol-3-phosphate production in the delivery of hemoglobin to the food vacuole; however, wortmannin inhibition was transient, which was likely due to the instability of this compound in culture medium. The simplicity, convenience and non-invasive nature of the Leu efflux assay described here makes it ideal for characterizing the in vivo kinetics of hemoglobin endocytosis and catabolism, for inhibitor target validation studies, and for medium-throughput screens to identify novel inhibitors of cytostomal endocytosis.
Collapse
Affiliation(s)
- Seema Dalal
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Michael Klemba
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA.
| |
Collapse
|
16
|
Coronado LM, Nadovich CT, Spadafora C. Malarial hemozoin: from target to tool. Biochim Biophys Acta Gen Subj 2014; 1840:2032-41. [PMID: 24556123 DOI: 10.1016/j.bbagen.2014.02.009] [Citation(s) in RCA: 145] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 01/26/2014] [Accepted: 02/10/2014] [Indexed: 02/07/2023]
Abstract
BACKGROUND Malaria is an extremely devastating disease that continues to affect millions of people each year. A distinctive attribute of malaria infected red blood cells is the presence of malarial pigment or the so-called hemozoin. Hemozoin is a biocrystal synthesized by Plasmodium and other blood-feeding parasites to avoid the toxicity of free heme derived from the digestion of hemoglobin during invasion of the erythrocytes. SCOPE OF REVIEW Hemozoin is involved in several aspects of the pathology of the disease as well as in important processes such as the immunogenicity elicited. It is known that the once best antimalarial drug, chloroquine, exerted its effect through interference with the process of hemozoin formation. In the present review we explore what is known about hemozoin, from hemoglobin digestion, to its final structural analysis, to its physicochemical properties, its role in the disease and notions of the possible mechanisms that could kill the parasite by disrupting the synthesis or integrity of this remarkable crystal. MAJOR CONCLUSIONS The importance and peculiarities of this biocrystal have given researchers a cause to consider it as a target for new antimalarials and to use it through unconventional approaches for diagnostics and therapeutics against the disease. GENERAL SIGNIFICANCE Hemozoin plays an essential role in the biology of malarial disease. Innovative ideas could use all the existing data on the unique chemical and biophysical properties of this macromolecule to come up with new ways of combating malaria.
Collapse
Affiliation(s)
- Lorena M Coronado
- Centro de Biología Celular y Molecular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, Ciudad del Saber, Panama; Department of Biotechnology, Acharya Nagarjuna University, Guntur 522 510, A.P., India
| | | | - Carmenza Spadafora
- Centro de Biología Celular y Molecular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, Ciudad del Saber, Panama.
| |
Collapse
|
17
|
Dou Z, Coppens I, Carruthers VB. Non-canonical maturation of two papain-family proteases in Toxoplasma gondii. J Biol Chem 2012; 288:3523-34. [PMID: 23250753 DOI: 10.1074/jbc.m112.443697] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Proteases regulate key events during infection by the pervasive intracellular parasite Toxoplasma gondii. Understanding how parasite proteases mature from an inactive zymogen to an active enzyme is expected to inform new strategies for blocking their actions. Herein, we show that T. gondii cathepsin B protease (TgCPB) does not undergo self-maturation but instead requires the expression of a second papain-family cathepsin protease, TgCPL. Using recombinant enzymes we also show that TgCPL is capable of partially maturing TgCPB in vitro. Consistent with this interrelationship, antibodies with validated specificity detected TgCPB in the lysosome-like vacuolar compartment along with TgCPL. Our findings also establish that TgCPB does not localize to the rhoptries as previously reported. Accordingly, rhoptry morphology and rhoptry protein maturation are normal in TgCPB knock-out parasites. Finally, we show that although maturation of TgCPL is independent of TgCPB, it may involve an additional protease(s) in conjunction with self-maturation.
Collapse
Affiliation(s)
- Zhicheng Dou
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| | | | | |
Collapse
|
18
|
Domínguez JN, Gamboa de Domínguez N, Rodrigues J, Acosta ME, Caraballo N, León C. Synthesis and antimalarial activity of urenyl Bis-chalcone in vitro and in vivo. J Enzyme Inhib Med Chem 2012; 28:1267-73. [DOI: 10.3109/14756366.2012.733383] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- José N. Domínguez
- Laboratorio de Síntesis Orgánica, Facultad de Farmacia, Universidad Central de Venezuela,
Caracas 1051, Venezuela
| | - Neira Gamboa de Domínguez
- Laboratorio de Bioquímica, Facultad de Farmacia, Universidad Central de Venezuela,
Caracas 1051, Venezuela
| | - Juan Rodrigues
- Laboratorio de Bioquímica, Facultad de Farmacia, Universidad Central de Venezuela,
Caracas 1051, Venezuela
| | - María Eugenia Acosta
- Laboratorio de Bioquímica, Facultad de Farmacia, Universidad Central de Venezuela,
Caracas 1051, Venezuela
| | - Noris Caraballo
- Departamento de Biología y Química, Universidad Pedagógica Experimental Libertador, Instituto Pedagógico de Caracas,
Caracas 1020, Venezuela
| | - Caritza León
- Departamento de Biología y Química, Universidad Pedagógica Experimental Libertador, Instituto Pedagógico de Caracas,
Caracas 1020, Venezuela
| |
Collapse
|
19
|
Shah F, Gut J, Legac J, Shivakumar D, Sherman W, Rosenthal PJ, Avery MA. Computer-aided drug design of falcipain inhibitors: virtual screening, structure-activity relationships, hydration site thermodynamics, and reactivity analysis. J Chem Inf Model 2012; 52:696-710. [PMID: 22332946 DOI: 10.1021/ci2005516] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Falcipains (FPs) are hemoglobinases of Plasmodium falciparum that are validated targets for the development of antimalarial chemotherapy. A combined ligand- and structure-based virtual screening of commercial databases was performed to identify structural analogs of virtual screening hits previously discovered in our laboratory. A total of 28 low micromolar inhibitors of FP-2 and FP-3 were identified and the structure-activity relationship (SAR) in each series was elaborated. The SAR of the compounds was unusually steep in some cases and could not be explained by a traditional analysis of the ligand-protein interactions (van der Waals, electrostatics, and hydrogen bonds). To gain further insights, a statistical thermodynamic analysis of explicit solvent in the ligand binding domains of FP-2 and FP-3 was carried out to understand the roles played by water molecules in binding of these inhibitors. Indeed, the energetics associated with the displacement of water molecules upon ligand binding explained some of the complex trends in the SAR. Furthermore, low potency of a subset of FP-2 inhibitors that could not be understood by the water energetics was explained in the context of poor chemical reactivity of the reactive centers of these compounds. The present study highlights the importance of considering energetic contributors to binding beyond traditional ligand-protein interactions.
Collapse
Affiliation(s)
- Falgun Shah
- Department of Medicinal Chemistry, School of Pharmacy, University of Mississippi, University, Mississippi 38677, USA
| | | | | | | | | | | | | |
Collapse
|
20
|
Cervantes S, Stout PE, Prudhomme J, Engel S, Bruton M, Cervantes M, Carter D, Tae-Chang Y, Hay ME, Aalbersberg W, Kubanek J, Le Roch KG. High content live cell imaging for the discovery of new antimalarial marine natural products. BMC Infect Dis 2012; 12:1. [PMID: 22214291 PMCID: PMC3268092 DOI: 10.1186/1471-2334-12-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 01/03/2012] [Indexed: 11/18/2022] Open
Abstract
Background The human malaria parasite remains a burden in developing nations. It is responsible for up to one million deaths a year, a number that could rise due to increasing multi-drug resistance to all antimalarial drugs currently available. Therefore, there is an urgent need for the discovery of new drug therapies. Recently, our laboratory developed a simple one-step fluorescence-based live cell-imaging assay to integrate the complex biology of the human malaria parasite into drug discovery. Here we used our newly developed live cell-imaging platform to discover novel marine natural products and their cellular phenotypic effects against the most lethal malaria parasite, Plasmodium falciparum. Methods A high content live cell imaging platform was used to screen marine extracts effects on malaria. Parasites were grown in vitro in the presence of extracts, stained with RNA sensitive dye, and imaged at timed intervals with the BD Pathway HT automated confocal microscope. Results Image analysis validated our new methodology at a larger scale level and revealed potential antimalarial activity of selected extracts with a minimal cytotoxic effect on host red blood cells. To further validate our assay, we investigated parasite's phenotypes when incubated with the purified bioactive natural product bromophycolide A. We show that bromophycolide A has a strong and specific morphological effect on parasites, similar to the ones observed from the initial extracts. Conclusion Collectively, our results show that high-content live cell-imaging (HCLCI) can be used to screen chemical libraries and identify parasite specific inhibitors with limited host cytotoxic effects. All together we provide new leads for the discovery of novel antimalarials.
Collapse
Affiliation(s)
- Serena Cervantes
- Department of Cell Biology and Neuroscience, University of California Riverside, Riverside, CA 92521, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Ojha PK, Roy K. Exploring molecular docking and QSAR studies of plasmepsin-II inhibitor di-tertiary amines as potential antimalarial compounds. MOLECULAR SIMULATION 2011. [DOI: 10.1080/08927022.2010.548384] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Probir Kumar Ojha
- a Drug Theoretics and Cheminformatics Laboratory, Division of Medicinal and Pharmaceutical Chemistry, Department of Pharmaceutical Technology , Jadavpur University , Kolkata, India
| | - Kunal Roy
- a Drug Theoretics and Cheminformatics Laboratory, Division of Medicinal and Pharmaceutical Chemistry, Department of Pharmaceutical Technology , Jadavpur University , Kolkata, India
| |
Collapse
|
22
|
Design and synthesis of protein-protein interaction mimics as Plasmodium falciparum cysteine protease, falcipain-2 inhibitors. Eur J Med Chem 2011; 46:2083-90. [PMID: 21429631 DOI: 10.1016/j.ejmech.2011.02.061] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 02/14/2011] [Accepted: 02/24/2011] [Indexed: 11/23/2022]
Abstract
Small peptides that mimic the protein-protein interactions between falcipain-2 and egg white cystatin, an endogenous inhibitor of cysteine proteases, were designed and synthesized and their effects on falcipain-2 activity were analyzed. The mimics are characterized by the presence of different linkers: γ-aminobutyric acid, cis-4-aminocyclohexane carboxylic acid and a macrocycle formed by GABA and two cysteines joined by a disulfide linkage. Some of these compounds showed falcipain-2 inhibition in the micromolar range and produced morphological abnormalities in the Plasmodium food vacuole. Although these peptides are less potent than cystatin, considering the reduction of amino acid residues and the capacity to cross membranes, this approach could be an interesting starting point for the development of a new class of anti-malarial drugs.
Collapse
|
23
|
Camacho J, Barazarte A, Gamboa N, Rodrigues J, Rojas R, Vaisberg A, Gilman R, Charris J. Synthesis and biological evaluation of benzimidazole-5-carbohydrazide derivatives as antimalarial, cytotoxic and antitubercular agents. Bioorg Med Chem 2011; 19:2023-9. [DOI: 10.1016/j.bmc.2011.01.050] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 01/20/2011] [Accepted: 01/24/2011] [Indexed: 10/18/2022]
|
24
|
Rodrigues JR, Lourenco D, Gamboa N. Disturbance in hemoglobin metabolism and in vivo antimalarial activity of azole antimycotics. Rev Inst Med Trop Sao Paulo 2011; 53:25-9. [DOI: 10.1590/s0036-46652011000100005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2009] [Accepted: 10/19/2010] [Indexed: 11/21/2022] Open
Abstract
Plasmodium parasites degrade host hemoglobin to obtain free amino acids, essential for protein synthesis. During this event, free toxic heme moieties crystallize spontaneously to produce a non-toxic pigment called hemozoin or ß-hematin. In this context, a group of azole antimycotics, clotrimazole (CTZ), ketoconazole (KTZ) and fluconazole (FCZ), were investigated for their abilities to inhibit ß-hematin synthesis (IßHS) and hemoglobin proteolysis (IHbP) in vitro. The ß-hematin synthesis was recorded by spectrophotometry at 405 nm and the hemoglobin proteolysis was determined by SDS-PAGE 12.5%, followed by densitometric analysis. Compounds were also assayed in vivo in a malaria murine model. CTZ and KTZ exhibited the maximal effects inhibiting both biochemical events, showing inhibition of β-hematin synthesis (IC50 values of 12.4 ± 0.9 µM and 14.4 ± 1.4 µM respectively) and inhibition of hemoglobin proteolysis (80.1 ± 2.0% and 55.3 ± 3.6%, respectively). There is a broad correlation to the in vivo results, especially CTZ, which reduced the parasitemia (%P) of infected-mice at 4th day post-infection significantly compared to non-treated controls (12.4 ± 3.0% compared to 26.6 ± 3.7%, p = 0.014) and prolonged the survival days post-infection. The results indicated that the inhibition of the hemoglobin metabolism by the azole antimycotics could be responsible for their antimalarial effect.
Collapse
|
25
|
Dou Z, Carruthers VB. Cathepsin proteases in Toxoplasma gondii. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 712:49-61. [PMID: 21660658 DOI: 10.1007/978-1-4419-8414-2_4] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cysteine proteases are important for the growth and survival of apicomplexan parasites that infect humans. The apicomplexan Toxoplasma gondii expresses five members of the C1 family of cysteine proteases, including one cathepsin L-like (TgCPL), one cathepsin B-like (TgCPB) and three cathepsin C-like (TgCPC1, 2 and 3) proteases. Recent genetic, biochemical and structural studies reveal that cathepsins function in microneme and rhoptry protein maturation, host cell invasion, replication and nutrient acquisition. here, we review the key features and roles of T. gondii cathepsins and discuss the therapeutic potential for specific inhibitor development.
Collapse
Affiliation(s)
- Zhicheng Dou
- Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, Michigan, USA
| | | |
Collapse
|
26
|
Rosenthal PJ. Falcipains and other cysteine proteases of malaria parasites. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 712:30-48. [PMID: 21660657 DOI: 10.1007/978-1-4419-8414-2_3] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A number of cysteine proteases of malaria parasites have been described and many more are suggested by analysis of the Plasmodium falciparum genome sequence. The best characterized of these proteases are the falcipains, a family of four papain-family enzymes. Falcipain-2 and falcipain-3 act in concert with other proteases to hydrolyze host erythrocyte hemoglobin in the parasite food vacuole. Disruption of the falcipain-2 gene led to a transient block in hemoglobin hydrolysis and parasites with increased sensitivity to protease inhibitors. Disruption of the falcipain-3 gene was not possible, strongly suggesting that this protease is essential for erythrocytic parasites. Disruption of the falcipain-1 gene did not alter development in erythrocytes, but led to decreased production of oocysts in mosquitoes. other papain-family proteases predicted by the genome sequence include dipeptidyl peptidases, a calpain homolog and serine-repeat antigens (SERAs). Dipeptidyl aminopeptidase 1 appears to be essential and localized to the food vacuole, suggesting a role in hemoglobin hydrolysis. Dipeptidyl aminopeptidase 3 appears to play a role in the rupture of erythrocytes by mature parasites. the P. falciparum calpain homolog gene could not be disrupted, suggesting that the protein is essential and a role in the parasite cell cycle has been suggested. Nine P. falciparum SERAs have cysteine protease motifs, but in some the active site cys is replaced by a Ser. Gene disruption studies suggested that SERA-5 and SERA-6 are essential. activation of SERA-5 by a serine protease seems to be required for merozoite egress from the erythrocyte. New drugs for malaria are greatly needed and cysteine proteases represent potential drug targets. cysteine protease inhibitors have demonstrated potent antimalarial effects and the optimization and testing of falcipain inhibitor antimalarials is underway.
Collapse
Affiliation(s)
- Philip J Rosenthal
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, California, USA.
| |
Collapse
|
27
|
Fu Y, Tilley L, Kenny S, Klonis N. Dual labeling with a far red probe permits analysis of growth and oxidative stress in P. falciparum-infected erythrocytes. Cytometry A 2010; 77:253-63. [PMID: 20091670 DOI: 10.1002/cyto.a.20856] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The malaria parasite, Plasmodium falciparum, develops within human erythrocytes, consuming host hemoglobin to support its own growth. Reactive oxygen species (superoxide and hydrogen peroxide) are by-products of hemoglobin digestion and are believed to exert significant oxidative stress on the parasite. We have characterized a cell permeant, far red fluorescent nucleic acid-binding dye, SYTO 61, that can be used to distinguish between uninfected and infected erythrocytes in a flow cytometric format. The spectral properties of SYTO 61 make it suitable for use in combination with the fluorescent reactive oxygen species reporter 5-(and-6)-chloromethyl-2',7'-dichlorodihydro-fluorescein diacetate acetyl ester. We have used this probe combination to measure oxidative stress in different stages of live P. falciparum. Low levels of the oxidized, fluorescent form of the reporter (2',7'-dichlorofluorescein, DCF) are detected in ring stage parasites; the DCF signal increases as the intraerythrocytic parasite matures into the trophozoite stage where active hemoglobin digestion occurs. Treatment of infected erythrocytes with the cysteine protease inhibitor, E-64, which inhibits hemoglobin digestion, decreases the DCF signal. We show that E-64 prevents schizont rupture but also causes delayed lethal effects when ring stage cultures are exposed to the drug. We also examined cultures of parasites in erythrocytes harboring 98% catalase inactivation and found no effect on growth and only a modest increase in DCF oxidation.
Collapse
Affiliation(s)
- Ying Fu
- Department of Biochemistry, La Trobe University, Melbourne, Victoria, Australia
| | | | | | | |
Collapse
|
28
|
Li F, Patra KP, Yowell CA, Dame JB, Chin K, Vinetz JM. Apical surface expression of aspartic protease Plasmepsin 4, a potential transmission-blocking target of the plasmodium ookinete. J Biol Chem 2010; 285:8076-83. [PMID: 20056606 DOI: 10.1074/jbc.m109.063388] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To invade its definitive host, the mosquito, the malaria parasite must cross the midgut peritrophic matrix that is composed of chitin cross-linked by chitin-binding proteins and then develop into an oocyst on the midgut basal lamina. Previous evidence indicates that Plasmodium ookinete-secreted chitinase is important in midgut invasion. The mechanistic role of other ookinete-secreted enzymes in midgut invasion has not been previously examined. De novo mass spectrometry sequencing of a protein obtained by benzamidine affinity column of Plasmodium gallinaceum ookinete axenic culture supernatant demonstrated the presence of an ookinete-secreted plasmepsin, an aspartic protease previously only known to be present in the digestive vacuole of asexual stage malaria parasites. This plasmepsin, the ortholog of Plasmodium falciparum plasmepsin 4, was designated PgPM4. PgPM4 and PgCHT2 (the P. gallinaceum ortholog of P. falciparum chitinase PfCHT1) are both localized on the ookinete apical surface, and both are present in micronemes. Aspartic protease inhibitors (peptidomimetic and natural product), calpain inhibitors, and anti-PgPM4 monoclonal antibodies significantly reduced parasite infectivity for mosquitoes. These results suggest that plasmepsin 4, previously known only to function in the digestive vacuole of asexual blood stage Plasmodium, plays a role in how the ookinete interacts with the mosquito midgut interactions as it becomes an oocyst. These data are the first to delineate a role for an aspartic protease in mediating Plasmodium invasion of the mosquito and demonstrate the potential for plasmepsin 4 as a malaria transmission-blocking vaccine target.
Collapse
Affiliation(s)
- Fengwu Li
- Division of Infectious Diseases, Department of Medicine, University of California San Diego School of Medicine, La Jolla, California 92093, USA
| | | | | | | | | | | |
Collapse
|
29
|
Mohapatra SC, Tiwari HK, Singla M, Rathi B, Sharma A, Mahiya K, Kumar M, Sinha S, Chauhan SS. Antimalarial evaluation of copper(II) nanohybrid solids: inhibition of plasmepsin II, a hemoglobin-degrading malarial aspartic protease from Plasmodium falciparum. J Biol Inorg Chem 2009; 15:373-85. [PMID: 19946719 DOI: 10.1007/s00775-009-0610-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2009] [Accepted: 11/03/2009] [Indexed: 10/20/2022]
Abstract
A new class of copper(II) nanohybrid solids, LCu(CH(3)COO)(2) and LCuCl(2), have been synthesized and characterized by transmission electron microscopy, dynamic light scattering, and IR spectroscopy, and have been found to be capped by a bis(benzimidazole) diamide ligand (L). The particle sizes of these nanohybrid solids were found to be in the ranges 5-10 and 60-70 nm, respectively. These nanohybrid solids were evaluated for their in vitro antimalarial activity against a chloroquine-sensitive isolate of Plasmodium falciparum (MRC 2). The interactions between these nanohybrid solids and plasmepsin II (an aspartic protease and a plausible novel target for antimalarial drug development), which is believed to be essential for hemoglobin degradation by the parasite, have been assayed by UV-vis spectroscopy and inhibition kinetics using Lineweaver-Burk plots. Our results suggest that these two compounds have antimalarial activities, and the IC(50) values (0.025-0.032 microg/ml) are similar to the IC(50) value of the standard drug chloroquine used in the bioassay. Lineweaver-Burk plots for inhibition of plasmepsin II by LCu(CH(3)COO)(2) and LCuCl(2) show that the inhibition is competitive with respect to the substrate. The inhibition constants of LCu(CH(3)COO)(2) and LCuCl(2) were found to be 10 and 13 microM, respectively. The IC(50) values for inhibition of plasmepsin II by LCu(CH(3)COO)(2) and LCuCl(2) were found to be 14 and 17 microM, respectively. Copper(II) metal capped by a benzimidazole group, which resembles the histidine group of copper proteins (galactose oxidase, beta-hydroxylase), could provide a suitable anchoring site on the nanosurface and thus could be useful for inhibition of target enzymes via binding to the S1/S3 pocket of the enzyme hydrophobically. Both copper(II) nanohybrid solids were found to be nontoxic against human hepatocellular carcinoma cells and were highly selective for plasmepsin II versus human cathepsin D. The pivotal mechanism of antimalarial activity of these compounds via plasmepsin II inhibition in the P. falciparum malaria parasite is demonstrated.
Collapse
|
30
|
Villamizar J, Pittelaud JP, Rodrigues JR, Gamboa N, Canudas N, Tropper E, Salazar F, Fuentes J. Synthesis and antimalarial activities of optically active labdane-type diterpenes. Nat Prod Res 2009; 23:891-902. [DOI: 10.1080/14786410802164048] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- José Villamizar
- a Centro de Química, Instituto Venezolano de Investigaciones Científicas (IVIC) , Apartado 21827, Caracas 1020-A, Venezuela
| | - Jean P. Pittelaud
- b Departamento de Química , Universidad Simón Bolívar , Caracas, Venezuela
| | - Juan R. Rodrigues
- c Facultad de Farmacia , Universidad Central de Venezuela , Caracas, Venezuela
| | - Neira Gamboa
- c Facultad de Farmacia , Universidad Central de Venezuela , Caracas, Venezuela
| | - Nieves Canudas
- b Departamento de Química , Universidad Simón Bolívar , Caracas, Venezuela
| | - Eleonora Tropper
- a Centro de Química, Instituto Venezolano de Investigaciones Científicas (IVIC) , Apartado 21827, Caracas 1020-A, Venezuela
| | - Franklin Salazar
- a Centro de Química, Instituto Venezolano de Investigaciones Científicas (IVIC) , Apartado 21827, Caracas 1020-A, Venezuela
| | - Juan Fuentes
- b Departamento de Química , Universidad Simón Bolívar , Caracas, Venezuela
| |
Collapse
|
31
|
Role of Plasmodium falciparum digestive vacuole plasmepsins in the specificity and antimalarial mode of action of cysteine and aspartic protease inhibitors. Antimicrob Agents Chemother 2009; 53:4968-78. [PMID: 19752273 DOI: 10.1128/aac.00882-09] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hemoglobin (Hb) degradation is essential for the growth of the intraerythrocytic stages of malarial parasites. This process, which occurs inside an acidic digestive vacuole (DV), is thought to involve the action of four aspartic proteases, termed plasmepsins (PMs). These enzymes have received considerable attention as potential antimalarial drug targets. Leveraging the availability of a set of PM-knockout lines generated in Plasmodium falciparum, we report here that a wide range of previously characterized or novel aspartic protease inhibitors exert their antimalarial activities independently of their effect on the DV PMs. We also assayed compounds previously shown to inhibit cysteine proteases residing in the DV. The most striking observation was a ninefold increase in the potency of the calpain inhibitor N-acetyl-leucinyl-leucinyl-norleucinal (ALLN) against parasites lacking all four DV PMs. Genetic ablation of PM III or PM IV also decreased the level of parasite resistance to the beta-hematin binding antimalarial chloroquine. On the basis of the findings of drug susceptibility and isobologram assays, as well as the findings of studies of the inhibition of Hb degradation, morphological analyses, and stage specificity, we conclude that the DV PMs and falcipain cysteine proteases act cooperatively in Hb hydrolysis. We also identify several aspartic protease inhibitors, designed to target DV PMs, which appear to act on alternative targets early in the intraerythrocytic life cycle. These include the potent diphenylurea compound GB-III-32, which was found to be fourfold less potent against a P. falciparum line overexpressing plasmepsin X than against the parental nontransformed parasite line. The identification of the mode of action of these inhibitors will be important for future antimalarial drug discovery efforts focusing on aspartic proteases.
Collapse
|
32
|
Capela R, Oliveira R, Gonçalves LM, Domingos A, Gut J, Rosenthal PJ, Lopes F, Moreira R. Artemisinin-dipeptidyl vinyl sulfone hybrid molecules: design, synthesis and preliminary SAR for antiplasmodial activity and falcipain-2 inhibition. Bioorg Med Chem Lett 2009; 19:3229-32. [PMID: 19435664 DOI: 10.1016/j.bmcl.2009.04.100] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Revised: 04/21/2009] [Accepted: 04/21/2009] [Indexed: 10/20/2022]
Abstract
A series of artemisinin-vinyl sulfone hybrid molecules with the potential to act in the parasite food vacuole via endoperoxide activation and falcipain inhibition was synthesized and screened for antiplasmodial activity and falcipain-2 inhibition. All conjugates were active against the Plasmodium falciparum W2 strain in the low nanomolar range and those containing the Leu-hPhe core inhibited falcipain-2 in low micromolar range.
Collapse
Affiliation(s)
- Rita Capela
- iMed.UL, Faculty of Pharmacy, University of Lisbon, Av Prof. Gama Pinto, 1649-003, Portugal
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Zareef M, Iqbal R, De Dominguez NG, Rodrigues J, Zaidi JH, Arfan M, Supuran CT. Synthesis and antimalarial activity of novel chiral and achiral benzenesulfonamides bearing 1, 3, 4-oxadiazole moieties. J Enzyme Inhib Med Chem 2008; 22:301-8. [PMID: 17674812 DOI: 10.1080/14756360601114569] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
A series of new benzenesulfonamides, most of which are chiral, incorporating 1, 3, 4-oxadiazole and amino acid moieties have been synthesized. Some of these compounds were screened for antimalarial activity and also evaluated for their ability to inhibit hem polymerization. The electrophoretic analysis indicated that one compound was effective in inhibiting the degradation of hemoglobin. The synthesized compounds were tested in mice infected with Plasmodium berghei. These derivatives have the potential for the development of novel antimalarial lead compounds.
Collapse
Affiliation(s)
- Muhammad Zareef
- Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan.
| | | | | | | | | | | | | |
Collapse
|
34
|
Korde R, Bhardwaj A, Singh R, Srivastava A, Chauhan VS, Bhatnagar RK, Malhotra P. A prodomain peptide of Plasmodium falciparum cysteine protease (falcipain-2) inhibits malaria parasite development. J Med Chem 2008; 51:3116-23. [PMID: 18461922 DOI: 10.1021/jm070735f] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Falcipain-2 (FP-2), a papain family cysteine protease of Plasmodium falciparum, is a promising target for antimalarial chemotherapy. Designing inhibitors that are highly selective for falcipain-2 has been difficult because of broad specificity of different cysteine proteinases. Because propeptide regions of cysteine proteases have been shown to inhibit their cognate enzymes specifically and selectively, in the present study, we evaluated the inhibitory potential of few falcipain-2 proregion peptides. A 15 residue peptide (PP1) inhibited falcipain-2 enzyme activity in vitro. Studies on the uptake of PP1 into the parasitized erythrocytes showed access of peptide into the infected RBCs. PP1 fused with Antennapedia homeoprotein internalization domain blocked hemoglobin hydrolysis, merozoite release and markedly inhibited Plasmodium falciparum growth and maturation. Together, our results identify a peptide derived from the proregion of falcipain-2 that blocks late-stage malaria parasite development in RBCs, suggesting the development of peptide and peptidometric drugs against the human malaria parasite.
Collapse
Affiliation(s)
- Reshma Korde
- International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India
| | | | | | | | | | | | | |
Collapse
|
35
|
Ersmark K, Samuelsson B, Hallberg A. Plasmepsins as potential targets for new antimalarial therapy. Med Res Rev 2007; 26:626-66. [PMID: 16838300 DOI: 10.1002/med.20082] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Malaria is one of the major diseases in the world. Due to the rapid spread of parasite resistance to available antimalarial drugs there is an urgent need for new antimalarials with novel mechanisms of action. Several promising targets for drug intervention have been revealed in recent years. This review addresses the parasitic aspartic proteases termed plasmepsins (Plms) that are involved in the hemoglobin catabolism that occurs during the erythrocytic stage of the malarial parasite life cycle. Four Plasmodium species are responsible for human malaria; P. vivax, P. ovale, P. malariae, and P. falciparum. This review focuses on inhibitors of the haemoglobin-degrading plasmepsins of the most lethal species, P. falciparum; Plm I, Plm II, Plm IV, and histo-aspartic protease (HAP). Previously, Plm II has attracted the most attention. With the identification and characterization of new plasmepsins and the results from recent plasmepsin knockout studies, it now seems clear that in order to achieve high-antiparasitic activities in P. falciparum-infected erythrocytes it is necessary to inhibit several of the haemoglobin-degrading plasmepsins. Herein we summarize the structure-activity relationships of the Plm I, II, IV, and HAP inhibitors. These inhibitors represent all classes which, to the best of our knowledge, have been disclosed in journal articles to date. The 3D structures of inhibitor/plasmepsin II complexes available in the protein data bank are briefly discussed and compared.
Collapse
Affiliation(s)
- Karolina Ersmark
- Department of Medicinal Chemistry, Uppsala University, BMC, SE-751 23 Uppsala, Sweden
| | | | | |
Collapse
|
36
|
Smythe WA, Joiner KA, Hoppe HC. Actin is required for endocytic trafficking in the malaria parasite Plasmodium falciparum. Cell Microbiol 2007; 10:452-64. [PMID: 17944961 DOI: 10.1111/j.1462-5822.2007.01058.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The intra-erythrocytic stages of the malaria parasite endocytose large quantities of the surrounding erythrocyte cytoplasm and deliver it to a digestive food vacuole via endocytic vesicles. Digestion provides amino acids for parasite protein synthesis and is required to maintain the osmotic integrity of the host cell. The parasite endocytic pathway has been described morphologically by electron microscopy, but the molecular mechanisms that mediate and regulate it remain elusive. Given the involvement of actin in endocytosis in other eukaryotes, we have used actin inhibitors to assess the requirement for this protein in the endocytic pathway of the human malaria parasite, Plasmodium falciparum. Treatment of cultures with cytochalasin D did not affect haemoglobin levels in the parasites when co-administered with protease inhibitors, and neither did it affect the uptake of the endocytic tracer horseradish peroxidase, suggesting the absence of actin in the mechanism of endocytosis. However, in the absence of protease inhibitors, treated parasites contained increased levels of haemoglobin due to an accumulation of enlarged endocytic vesicles, as determined by immunofluorescence and electron microscopy, suggesting a role for actin in vesicle trafficking, possibly by mediating vesicle maturation and/or fusion to the digestive vacuole. In contrast to cytochalasin D, treatment with jasplakinolide led to an inhibition of endocytosis, an accumulation of vesicles closer to the plasma membrane and a marked concentration of actin in the parasite cortex. We propose that the stabilization of cortical actin filaments by jasplakinolide interferes with normal endocytic vesicle formation and migration from the cell periphery.
Collapse
Affiliation(s)
- Wynand A Smythe
- Division of Pharmacology and Institute of Infectious Diseases and Molecular Medicine, University of Cape Town Medical School, Cape Town, 7925, South Africa
| | | | | |
Collapse
|
37
|
Charris J, Barazarte A, Domínguez J, Lobo G, Camacho J, Ferrer R, Gamboa N, Rodrigues J, Capparelli MV. Synthesis and antimalarial activity of ethyl 3-amino-4-oxo-9-(phenylsubstituted)thieno[2,3-b]quinoline-2-carboxylate derivatives. J Heterocycl Chem 2007. [DOI: 10.1002/jhet.5570440320] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
38
|
Scory S, Stierhof YD, Caffrey CR, Steverding D. The cysteine proteinase inhibitor Z-Phe-Ala-CHN2 alters cell morphology and cell division activity of Trypanosoma brucei bloodstream forms in vivo. KINETOPLASTID BIOLOGY AND DISEASE 2007; 6:2. [PMID: 17328798 PMCID: PMC1810305 DOI: 10.1186/1475-9292-6-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2006] [Accepted: 02/28/2007] [Indexed: 11/25/2022]
Abstract
Background Current chemotherapy of human African trypanosomiasis or sleeping sickness relies on drugs developed decades ago, some of which show toxic side effects. One promising line of research towards the development of novel anti-trypanosomal drugs are small-molecule inhibitors of Trypanosoma brucei cysteine proteinases. Results In this study, we demonstrate that treatment of T. brucei-infected mice with the inhibitor, carbobenzoxy-phenylalanyl-alanine-diazomethyl ketone (Z-Phe-Ala-CHN2), alters parasite morphology and inhibits cell division. Following daily intra-peritoneal administration of 250 mg kg-1 of Z-Phe-Ala-CHN2 on days three and four post infection (p.i.), stumpy-like forms with enlarged lysosomes were evident by day five p.i. In addition, trypanosomes exposed to the inhibitor had a 65% greater protein content than those from control mice. Also, in contrast to the normal 16% of parasites containing two kinetoplasts – a hallmark of active mitosis, only 4% of trypanosomes exposed to the inhibitor were actively dividing, indicating cell cycle-arrest. Conclusion We suggest that inhibition of endogenous cysteine proteinases by Z-Phe-Ala-CHN2 depletes the parasite of essential nutrients necessary for DNA synthesis, which in turn, prevents progression of the cell cycle. This arrest then triggers differentiation of the long-slender into short-stumpy forms.
Collapse
Affiliation(s)
- Stefan Scory
- Abteilung Parasitologie, Hygiene-Institut der Ruprecht Karls-Universität, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - York-Dieter Stierhof
- Abteilung Membranbiochemie, Max-Planck-Institut für Biologie, Corrensstraße 38, 72076 Tübingen, Germany
- Zentrum für Molekularbiologie der Pflanzen, Eberhard-Karls-Universität, Auf der Morgenstelle 1, 72076 Tübingen, Germany
| | - Conor R Caffrey
- Abteilung Tropenhygiene und Öffentliches Gesundheitswesen, Hygiene-Institut der Ruprecht Karls-Universität, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
- Sandler Center for Basic Research in Parasitic Diseases, California Institute for Quantitative Biomedical Research, Byers Hall, University of California San Francisco, 1700 4th Street, San Francisco, CA94158-2330, USA
| | - Dietmar Steverding
- Abteilung Parasitologie, Hygiene-Institut der Ruprecht Karls-Universität, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
- Present address: BioMedical Research Centre, School of Medicine, Health Policy and Practice, University of East Anglia, Norwich NR4 7TJ, UK
| |
Collapse
|
39
|
León C, Rodrigues J, Gamboa de Domínguez N, Charris J, Gut J, Rosenthal PJ, Domínguez JN. Synthesis and evaluation of sulfonylurea derivatives as novel antimalarials. Eur J Med Chem 2007; 42:735-42. [PMID: 17321641 DOI: 10.1016/j.ejmech.2007.01.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Accepted: 11/14/2005] [Indexed: 10/23/2022]
Abstract
We have synthesized a series of sulfonylureas and have tested their antimalarial activities, including inhibition of in vitro development of a chloroquine-resistant strain of Plasmodium falciparum, in vitro hemoglobin hydrolysis, hemozoin formation, and development of Plasmodium berghei in murine malaria. The most active antimalarial compound was (E)-1-[4'-(3-(2,4-difluorophenyl)acryloyl)phenyl]-3-tosylurea (22) with an IC(50) of 1.2microM against cultured P. falciparum parasites. Biological results suggest a fairly potent antimalarial activity for this derivative, but also imply that its activity may arise from an unknown mechanism. Indeed, these compounds may act against malaria parasites through multiple mechanisms.
Collapse
Affiliation(s)
- Caritza León
- Laboratorio de Síntesis Orgánica, Facultad de Farmacia, Universidad Central de Venezuela, Caracas 1051, Venezuela
| | | | | | | | | | | | | |
Collapse
|
40
|
Rodrigues JR, Gamboa de Domínguez N. Plasmodium berghei: In vitro and in vivo activity of dequalinium. Exp Parasitol 2007; 115:19-24. [PMID: 16814285 DOI: 10.1016/j.exppara.2006.05.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Revised: 04/29/2006] [Accepted: 05/09/2006] [Indexed: 10/24/2022]
Abstract
Bisquinoline compounds have exhibited remarkable activity in vitro and in vivo against Plasmodium parasites by inhibition of heme detoxification. We have tested the ability of dequalinium 1,1'-(1,10-decanediyl)bis(4-amino-2-methylquinoline), a known antimicrobial agent, to inhibit beta-hematin synthesis using a non-emzymatic colorimetric assay and globin proteolysis by electrophoretic analysis (SDS-PAGE-15%). Dequalinium was able to inhibit both processes in vitro with close correlation to a murine malaria model, reducing parasitemia levels, prolonging the survival time post-infection and curing 40% of infected mice using a combination therapy with a loading dose of chloroquine. These results confirm that dequalinium is a promising lead for antimalarial drug development.
Collapse
Affiliation(s)
- Juan Ricardo Rodrigues
- Unidad de Bioquímica, Facultad de Farmacia, Universidad Central de Venezuela, Apartado 47206, Los Chaguaramos, Caracas 1051-A, Venezuela.
| | | |
Collapse
|
41
|
Stack CM, Lowther J, Cunningham E, Donnelly S, Gardiner DL, Trenholme KR, Skinner-Adams TS, Teuscher F, Grembecka J, Mucha A, Kafarski P, Lua L, Bell A, Dalton JP. Characterization of the Plasmodium falciparum M17 Leucyl Aminopeptidase. J Biol Chem 2007; 282:2069-80. [PMID: 17107951 DOI: 10.1074/jbc.m609251200] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Amino acids generated from the catabolism of hemoglobin by intra-erythrocytic malaria parasites are not only essential for protein synthesis but also function in maintaining an osmotically stable environment, and creating a gradient by which amino acids that are rare or not present in hemoglobin are drawn into the parasite from host serum. We have proposed that a Plasmodium falciparum M17 leucyl aminopeptidase (PfLAP) generates and regulates the internal pool of free amino acids and therefore represents a target for novel antimalarial drugs. This enzyme has been expressed in insect cells as a functional 320-kDa homo-hexamer that is optimally active at neutral or alkaline pH, is dependent on metal ions for activity, and exhibits a substrate preference for N-terminally exposed hydrophobic amino acids, particularly leucine. PfLAP is produced by all stages in the intra-erythrocytic developmental cycle of malaria but was most highly expressed by trophozoites, a stage at which hemoglobin degradation and parasite protein synthesis are elevated. The enzyme was located by immunohistochemical methods and by transfecting malaria cells with a PfLAP-green fluorescent protein construct, to the cytosolic compartment of the cell at all developmental stages, including segregated merozoites. Amino acid dipeptide analogs, such as bestatin and its derivatives, are potent inhibitors of the protease and also block the growth of P. falciparum malaria parasites in culture. This study provides a biochemical basis for the antimalarial activity of aminopeptidase inhibitors. Availability of functionally active recombinant PfLAP, coupled with a simple enzymatic readout, will aid medicinal chemistry and/or high throughput approaches for the future design/discovery of new antimalarial drugs.
Collapse
Affiliation(s)
- Colin M Stack
- Institute for the Biotechnology of Infectious Diseases, University of Technology Sydney, Level 6, Building 4, Corner of Thomas and Harris Street, Ultimo, Sydney, New South Wales 2007, Australia
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Ponpuak M, Klemba M, Park M, Gluzman IY, Lamppa GK, Goldberg DE. A role for falcilysin in transit peptide degradation in thePlasmodium falciparumapicoplast. Mol Microbiol 2006; 63:314-34. [PMID: 17074076 DOI: 10.1111/j.1365-2958.2006.05443.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Falcilysin (FLN) is a zinc metalloprotease thought to degrade globin peptides in the acidic vacuole of the human malaria parasite Plasmodium falciparum. The enzyme has been found to have acidic or neutral pH optima on different peptides and to have additional distribution outside the food vacuole. These data suggested that FLN has an additional function in the parasite. To further probe the functions of FLN, we created a transgenic parasite clone expressing a chromosomally encoded FLN-GFP fusion. Unexpectedly, FLN was found in the apicoplast, an essential chloroplast-like organelle. Nuclear encoded apicoplast proteins are targeted to the organelle by a bipartite N-terminal sequence comprised of a signal sequence followed by a positively charged transit peptide domain. Free transit peptides are thought to be toxic to the plastid and need to be rapidly degraded after proteolytic release from proproteins. We hypothesized that FLN may participate in transit peptide degradation in the apicoplast based on its preference for basic residues at neutral pH and on phylogenetic comparison with other M16 family metalloproteases. In vitro cleavage by FLN of the transit peptide from the apicoplast-resident acyl carrier protein supports this idea. The importance of FLN for parasite development is suggested by our inability to truncate the chromosomal FLN open reading frame. Our work indicates that FLN is an attractive target for antimalarial development.
Collapse
Affiliation(s)
- Marisa Ponpuak
- Howard Hughes Medical Institute, Washington University, Departments of Molecular Microbiology and Medicine, St. Louis, MO 63110, USA
| | | | | | | | | | | |
Collapse
|
43
|
Hurd H, Grant KM, Arambage SC. Apoptosis-like death as a feature of malaria infection in mosquitoes. Parasitology 2006; 132 Suppl:S33-47. [PMID: 17018164 DOI: 10.1017/s0031182006000849] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Malaria parasites of the genusPlasmodiummake a hazardous journey through their mosquito vectors. The majority die in the process, many as a result of the action of mosquito defence mechanisms. The mosquito too is not unscathed by the encounter with these parasites. Tissue damage occurs as a result of mid-gut invasion and reproductive fitness is lost when many developing ovarian follicles are resorbed. Here we discuss some of the mechanisms that are involved in killing the parasite and in the self-defence mechanisms employed by the mosquito to repair the mid-gut epithelium and to manipulate resources altering the trade-off position that balances reproduction and survival. In all cases, cells die by apoptotic-like mechanisms. In the midgut cells, apoptosis-induction pathways are being elucidated, the molecules involved in apoptosis are being recognised andDrosophilahomologues sought. The death of ookinetes in the mosquito mid-gut lumen is associated with caspase-like activity and, although homologues of mammalian caspases are not present in the malaria genome, other cysteine proteases that are potential candidates have been discussed. In the ovary, apoptosis of patches of follicular epithelial cells is followed by resorption of the developing follicle and a subsequent loss of egg production in that follicle.
Collapse
Affiliation(s)
- H Hurd
- Centre for Applied Entomology and Parasitology, Institute for Science and Technology in Medicine, University of Keele, Staffordshire, ST5 5BG, UK. h.hurd.keele.ac.uk
| | | | | |
Collapse
|
44
|
Andrews KT, Fairlie DP, Madala PK, Ray J, Wyatt DM, Hilton PM, Melville LA, Beattie L, Gardiner DL, Reid RC, Stoermer MJ, Skinner-Adams T, Berry C, McCarthy JS. Potencies of human immunodeficiency virus protease inhibitors in vitro against Plasmodium falciparum and in vivo against murine malaria. Antimicrob Agents Chemother 2006; 50:639-48. [PMID: 16436721 PMCID: PMC1366900 DOI: 10.1128/aac.50.2.639-648.2006] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Parasite resistance to antimalarial drugs is a serious threat to human health, and novel agents that act on enzymes essential for parasite metabolism, such as proteases, are attractive targets for drug development. Recent studies have shown that clinically utilized human immunodeficiency virus (HIV) protease inhibitors can inhibit the in vitro growth of Plasmodium falciparum at or below concentrations found in human plasma after oral drug administration. The most potent in vitro antimalarial effects have been obtained for parasites treated with saquinavir, ritonavir, or lopinavir, findings confirmed in this study for a genetically distinct P. falciparum line (3D7). To investigate the potential in vivo activity of antiretroviral protease inhibitors (ARPIs) against malaria, we examined the effect of ARPI combinations in a murine model of malaria. In mice infected with Plasmodium chabaudi AS and treated orally with ritonavir-saquinavir or ritonavir-lopinavir, a delay in patency and a significant attenuation of parasitemia were observed. Using modeling and ligand docking studies we examined putative ligand binding sites of ARPIs in aspartyl proteases of P. falciparum (plasmepsins II and IV) and P. chabaudi (plasmepsin) and found that these in silico analyses support the antimalarial activity hypothesized to be mediated through inhibition of these enzymes. In addition, in vitro enzyme assays demonstrated that P. falciparum plasmepsins II and IV are both inhibited by the ARPIs saquinavir, ritonavir, and lopinavir. The combined results suggest that ARPIs have useful antimalarial activity that may be especially relevant in geographical regions where HIV and P. falciparum infections are both endemic.
Collapse
Affiliation(s)
- Katherine T Andrews
- Queensland Institute of Medical Research and Australian Centre for International and Tropical Health and Nutrition, 300 Herston Road, Herston, Queensland 4029, Australia.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Dasaradhi PVN, Mohmmed A, Kumar A, Hossain MJ, Bhatnagar RK, Chauhan VS, Malhotra P. A role of falcipain-2, principal cysteine proteases of Plasmodium falciparum in merozoite egression. Biochem Biophys Res Commun 2005; 336:1062-8. [PMID: 16165088 DOI: 10.1016/j.bbrc.2005.08.213] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2005] [Accepted: 08/26/2005] [Indexed: 10/25/2022]
Abstract
The process of merozoite release in Plasmodium falciparum involves rupture of the parasitophorous vacuole membrane and erythrocyte plasma membrane. Through the use of protease inhibitors that halt the merozoite release, a number of parasite proteases, especially serine, aspartic, and cysteine proteases, have been implicated in the schizont rupture. To understand the precise role of cysteine proteases in the merozoite release, in the present study, we treated P. falciparum cultures with siRNAs corresponding to falcipain-1, falcipain-2, and falcipain-3, the three papain-family proteases of the parasite. Treatment of malaria parasites with either of the falcipain siRNAs considerably reduced parasite growth. Morphological examination of the siRNA treated parasite cultures revealed that most of the parasites in falcipain-2 siRNA treated cultures were arrested at schizont stage. Analysis of a transgenic P. falciparum line expressing chimeric-GFP upon treatment with falcipain-2 siRNA revealed block in the rupture of erythrocyte membrane at the time of merozoite egression. These results suggest that falcipain-2 is an important parasitic protease that participates in hemoglobin degradation and in the merozoite release.
Collapse
Affiliation(s)
- Palakodeti V N Dasaradhi
- International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India
| | | | | | | | | | | | | |
Collapse
|
46
|
Black CG, Wu T, Wang L, Topolska AE, Coppel RL. MSP8 is a non-essential merozoite surface protein in Plasmodium falciparum. Mol Biochem Parasitol 2005; 144:27-35. [PMID: 16125802 DOI: 10.1016/j.molbiopara.2005.06.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2005] [Revised: 05/29/2005] [Accepted: 06/05/2005] [Indexed: 10/25/2022]
Abstract
MSP8 is a recently identified merozoite surface protein that shares similar structural features with the leading vaccine candidate MSP1. Both proteins contain two C-terminal epidermal growth factor (EGF)-like domains, a glycosylphosphatidylinositol (GPI) anchor attachment sequence and undergo proteolytic processing. By double recombination, we have disrupted the MSP8 gene in P. falciparum 3D7 parasites, and confirmed integration by southern hybridisation and PCR. Western blot analysis of lysates from asynchronous cultures and isolated merozoites demonstrated the absence of MSP8 in two cloned knockout lines. There was no significant difference in growth rate observed between 3D7 and the cloned DeltaMSP8 lines. Thus, unlike MSP1, MSP8 is not required for asexual stage parasite growth and replication in vitro. Further analysis of the cloned lines showed that loss of MSP8 had no effect on the levels of expression of other merozoite surface proteins including MSP1-5, 7 and 10. Stage-specific immunoblots showed that MSP8 expression commences in late rings and extends throughout the rest of the erythrocytic life cycle in the 3D7 parent line, but is absent from all stages in the DeltaMSP8 transfectants.
Collapse
Affiliation(s)
- Casilda G Black
- Department of Microbiology and the Victorian Bioinformatics Consortium, Monash University, Clayton, Vic. 3800, Australia.
| | | | | | | | | |
Collapse
|
47
|
Binkert C, Frigerio M, Jones A, Meyer S, Pesenti C, Prade L, Viani F, Zanda M. Replacement of Isobutyl by Trifluoromethyl in Pepstatin A Selectively Affects Inhibition of Aspartic Proteinases. Chembiochem 2005; 7:181-6. [PMID: 16307463 DOI: 10.1002/cbic.200500180] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Two bis-trifluoromethyl pepstatin A analogues, carboxylic acid 1 and its methyl ester 2, have been synthesised in order to probe the properties and size of the trifluoromethyl (Tfm) group and compare it to the "bigger" isobutyl that is present in pepstatin A. The results demonstrate that Tfm can effectively replace the isobutyl chain as far as inhibitory activity against plasmepsin II (PM II), an aspartic proteinase from Plasmodium falciparum, is concerned. On the other hand, replacement of isobutyl by Tfm selectively affected activity against other aspartic proteinases tested. Two lines of evidence led to these conclusions. Firstly, compounds 1 and 2 retained single-digit nanomolar inhibitory activity against PM II, but were markedly less active against PM IV, cathepsin D and cathepsin E. Secondly, the X-ray crystal structures of the three complexes of PM II with 1, 2 and pepstatin A were obtained at 2.8, 2.4 and 1.7 A resolution, respectively. High overall similarity among the three complexes indicated that the central Tfm was well accommodated in the lipophilic S1 pocket of PM II, where it was involved in tight hydrophobic contacts. The interaction of PM II with Phe111 appeared to be crucial. Comparison of the crystal structures presented here, with X-ray structures or structural models of PM IV and cathepsin D, allowed an interpretation of the inhibition profiles of pepstatin A and its Tfm variants against these three enzymes. Interactions of the P1 side chain with amino acids that point into the S1 pocket appear to be critical for inhibitory activity. In summary, Tfm can be used to replace an isobutyl group and can affect the selectivity profile of a compound. These findings have implications for the design of novel bioactive molecules and synthetic mimics of natural compounds.
Collapse
Affiliation(s)
- Christoph Binkert
- Actelion Pharmaceuticals Ltd. Gewerbestrasse 16, 4123 Allschwil, Switzerland.
| | | | | | | | | | | | | | | |
Collapse
|
48
|
Gardiner DL, Trenholme KR, Skinner-Adams TS, Stack CM, Dalton JP. Overexpression of leucyl aminopeptidase in Plasmodium falciparum parasites. Target for the antimalarial activity of bestatin. J Biol Chem 2005; 281:1741-5. [PMID: 16286469 DOI: 10.1074/jbc.m508955200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Malaria aminopeptidases are important in the generation and regulation of free amino acids that are used in protein anabolism and for maintaining osmotic stability within the infected erythrocyte. The intraerythrocytic development of malaria parasites is blocked when the activity of aminopeptidases is specifically inhibited by reagents such as bestatin. One of the major aminopeptidases of malaria parasites is a leucyl aminopeptidase of the M17 family. We reasoned that, when this enzyme was the target of bestatin inhibition, its overexpression in malaria cells would lead to a reduced sensitivity to the inhibitor. To address this supposition, transgenic Plasmodium falciparum parasites overexpressing the leucyl aminopeptidase were generated by transfection with a plasmid that housed the full-length gene. Transgenic parasites expressed a 65-kDa protein close to the predicted molecule size of 67.831 kDa for the introduced leucyl aminopeptidase, and immunofluorescence studies localized the protein to the cytosol, the location of the native enzyme. The product of the transgene was shown to be functionally active with cytosolic extracts of transgenic parasites exhibiting twice the leucyl aminopeptidase activity compared with wild-type parasites. In vitro inhibitor sensitivity assays demonstrated that the transgenic parasites were more resistant to bestatin (EC50 64 microM) compared with the parent parasites (EC50 25 microM). Overexpression of genes in malaria parasites would have general application in the identification and validation of targets for antimalarial drugs.
Collapse
Affiliation(s)
- Donald L Gardiner
- Malaria Biology Laboratory, The Australian Centre for International and Tropical Health and Nutrition, Queensland Institute of Medical Research, 300 Herston Road, Herston, Brisbane QLD 4029, Australia
| | | | | | | | | |
Collapse
|
49
|
Ersmark K, Nervall M, Hamelink E, Janka LK, Clemente JC, Dunn BM, Blackman MJ, Samuelsson B, Aqvist J, Hallberg A. Synthesis of malarial plasmepsin inhibitors and prediction of binding modes by molecular dynamics simulations. J Med Chem 2005; 48:6090-106. [PMID: 16162010 DOI: 10.1021/jm050463l] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of inhibitors of the malarial aspartic proteases Plm I and II have been synthesized with L-mannitol as precursor. These inhibitors are characterized by either a diacylhydrazine or a five-membered oxadiazole ring replacing backbone amide functionalities. Molecular dynamics simulations were applied in the design process. The computationally predicted Plm II Ki values were generally in excellent agreement with the biological results. The diacylhydrazine was found to be superior over the oxadiazole as an amide bond replacement in the Plm I and II inhibitors studied. An extensive flexibility of the S2' pocket was captured by the simulations predicting the binding mode of the unsymmetrical inhibitors. Plm I and II inhibitors with single digit nanomolar Ki values devoid of inhibitory activity toward human Cat D were identified. One compound, lacking amide bonds, was found to be Plm IV selective and very potent, with a Ki value of 35 nM.
Collapse
Affiliation(s)
- Karolina Ersmark
- Department of Medicinal Chemistry, Uppsala University, BMC, Box 574, 751 23 Uppsala, Sweden
| | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Parikh S, Gut J, Istvan E, Goldberg DE, Havlir DV, Rosenthal PJ. Antimalarial activity of human immunodeficiency virus type 1 protease inhibitors. Antimicrob Agents Chemother 2005; 49:2983-5. [PMID: 15980379 PMCID: PMC1168637 DOI: 10.1128/aac.49.7.2983-2985.2005] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aspartic proteases play key roles in the biology of malaria parasites and human immunodeficiency virus type 1 (HIV-1). We tested the activity of seven HIV-1 protease inhibitors against cultured Plasmodium falciparum. All compounds inhibited the development of parasites at pharmacologically relevant concentrations. The most potent compound, lopinavir, was active against parasites (50% inhibitory concentration [IC50], 0.9 to 2.1 microM) at concentrations well below those achieved by ritonavir-boosted lopinavir therapy. Lopinavir also inhibited the P. falciparum aspartic protease plasmepsin II at a similar concentration (IC50, 2.7 microM). These findings suggest that use of HIV-1 protease inhibitors may offer clinically relevant antimalarial activity.
Collapse
Affiliation(s)
- Sunil Parikh
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, Box 0811, San Francisco, California 94110, USA.
| | | | | | | | | | | |
Collapse
|