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Buthelezi MN, Tshililo VG, Kappo AP, Simelane MBC. Phytochemical evaluation of Ziziphus mucronata and Xysmalobium undulutum towards the discovery and development of anti-malarial drugs. Malar J 2024; 23:141. [PMID: 38734650 PMCID: PMC11088772 DOI: 10.1186/s12936-024-04976-1] [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: 02/22/2024] [Accepted: 05/04/2024] [Indexed: 05/13/2024] Open
Abstract
BACKGROUND The development of resistance by Plasmodium falciparum is a burdening hazard that continues to undermine the strides made to alleviate malaria. As such, there is an increasing need to find new alternative strategies. This study evaluated and validated 2 medicinal plants used in traditional medicine to treat malaria. METHODS Inspired by their ethnobotanical reputation of being effective against malaria, Ziziphus mucronata and Xysmalobium undulutum were collected and sequentially extracted using hexane (HEX), ethyl acetate (ETA), Dichloromethane (DCM) and methanol (MTL). The resulting crude extracts were screened for their anti-malarial and cytotoxic potential using the parasite lactate dehydrogenase (pLDH) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, respectively. This was followed by isolating the active compounds from the DCM extract of Z. mucronata using silica gel chromatography and structural elucidation using spectroscopic techniques (NMR: 1H, 12C, and DEPT). The active compounds were then targeted against P. falciparum heat shock protein 70-1 (PfHsp70-1) using Autodock Vina, followed by in vitro validation assays using ultraviolet-visible (UV-VIS) spectroscopy and the malate dehydrogenase (MDH) chaperone activity assay. RESULTS The extracts except those of methanol displayed anti-malarial potential with varying IC50 values, Z. mucronata HEX (11.69 ± 3.84 µg/mL), ETA (7.25 ± 1.41 µg/mL), DCM (5.49 ± 0.03 µg/mL), and X. undulutum HEX (4.9 ± 0.037 µg/mL), ETA (17.46 ± 0.024 µg/mL) and DCM (19.27 ± 0.492 µg/mL). The extracts exhibited minimal cytotoxicity except for the ETA and DCM of Z. mucronata with CC50 values of 10.96 and 10.01 µg/mL, respectively. Isolation and structural characterization of the active compounds from the DCM extracts revealed that betulinic acid (19.95 ± 1.53 µg/mL) and lupeol (7.56 ± 2.03 µg/mL) were responsible for the anti-malarial activity and had no considerable cytotoxicity (CC50 > µg/mL). Molecular docking suggested strong binding between PfHsp70-1, betulinic acid (- 6.8 kcal/mol), and lupeol (- 6.9 kcal/mol). Meanwhile, the in vitro validation assays revealed the disruption of the protein structural elements and chaperone function. CONCLUSION This study proves that X undulutum and Z. mucronata have anti-malarial potential and that betulinic acid and lupeol are responsible for the activity seen on Z. mucronata. They also make a case for guided purification of new phytochemicals in the other extracts and support the notion of considering medicinal plants to discover new anti-malarials.
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Affiliation(s)
- Muzi N Buthelezi
- Department of Biochemistry, Faculty of Science, University of Johannesburg, Auckland Park Kingsway Campus, Johannesburg, South Africa
| | - Vhahangwele G Tshililo
- Department of Biochemistry, Faculty of Science, University of Johannesburg, Auckland Park Kingsway Campus, Johannesburg, South Africa
| | - Abidemi P Kappo
- Department of Biochemistry, Faculty of Science, University of Johannesburg, Auckland Park Kingsway Campus, Johannesburg, South Africa
| | - Mthokozisi B C Simelane
- Department of Biochemistry, Faculty of Science, University of Johannesburg, Auckland Park Kingsway Campus, Johannesburg, South Africa.
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2
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Ahmad T, Alhammadi BA, Almaazmi SY, Arafa S, Blatch GL, Dutta T, Gestwicki JE, Keyzers RA, Shonhai A, Singh H. Plasmodium falciparum heat shock proteins as antimalarial drug targets: An update. Cell Stress Chaperones 2024; 29:326-337. [PMID: 38518861 PMCID: PMC10990865 DOI: 10.1016/j.cstres.2024.03.007] [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: 01/15/2024] [Revised: 02/25/2024] [Accepted: 03/18/2024] [Indexed: 03/24/2024] Open
Abstract
Global efforts to eradicate malaria are threatened by multiple factors, particularly the emergence of antimalarial drug resistant strains of Plasmodium falciparum. Heat shock proteins (HSPs), particularly P. falciparum HSPs (PfHSPs), represent promising drug targets due to their essential roles in parasite survival and virulence across the various life cycle stages. Despite structural similarities between human and malarial HSPs posing challenges, there is substantial evidence for subtle differences that could be exploited for selective drug targeting. This review provides an update on the potential of targeting various PfHSP families (particularly PfHSP40, PfHSP70, and PfHSP90) and their interactions within PfHSP complexes as a strategy to develop new antimalarial drugs. In addition, the need for a deeper understanding of the role of HSP complexes at the host-parasite interface is highlighted, especially heterologous partnerships between human and malarial HSPs, as this opens novel opportunities for targeting protein-protein interactions crucial for malaria parasite survival and pathogenesis.
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Affiliation(s)
- Tanveer Ahmad
- Faculty of Health Sciences, Higher Colleges of Technology, Sharjah, United Arab Emirates
| | - Bushra A Alhammadi
- Faculty of Health Sciences, Higher Colleges of Technology, Sharjah, United Arab Emirates
| | - Shaikha Y Almaazmi
- Faculty of Health Sciences, Higher Colleges of Technology, Sharjah, United Arab Emirates
| | - Sahar Arafa
- Faculty of Health Sciences, Higher Colleges of Technology, Sharjah, United Arab Emirates
| | - Gregory L Blatch
- Faculty of Health Sciences, Higher Colleges of Technology, Sharjah, United Arab Emirates; Biomedical Biotechnology Research Unit, Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, South Africa.
| | - Tanima Dutta
- Department of Diagnostic Genomics, Pathwest, QEII Medical Centre, Nedlands, Western Australia, Australia
| | - Jason E Gestwicki
- Department of Pharmaceutical Chemistry and the Institute for Neurodegenerative Diseases, University of California San Francisco, San Francisco, CA, USA
| | - Robert A Keyzers
- Centre for Biodiscovery & School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Addmore Shonhai
- Department of Biochemistry and Microbiology, University of Venda, Thohoyandou, South Africa
| | - Harpreet Singh
- Department of Bioinformatics, Hans Raj Mahila Maha Vidyalaya, Jalandhar, Punjab, India
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3
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Opoku F, Govender P, Shonhai A, Simelane MB. Iso-mukaadial acetate and ursolic acid acetate bind to Plasmodium Falciparum heat shock protein 70: towards targeting parasite protein folding pathway. BMC Chem 2024; 18:55. [PMID: 38500145 PMCID: PMC10949600 DOI: 10.1186/s13065-024-01159-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 03/07/2024] [Indexed: 03/20/2024] Open
Abstract
Plasmodium falciparum is the most lethal malaria parasite. P. falciparum Hsp70 (PfHsp70) is an essential molecular chaperone (facilitates protein folding) and is deemed a prospective antimalarial drug target. The present study investigates the binding capabilities of select plant derivatives, iso-mukaadial acetate (IMA) and ursolic acid acetate (UAA), against P. falciparum using an in silico docking approach. The interaction between the ligands and PfHsp70 was evaluated using plasmon resonance (SPR) analysis. Molecular docking, binding free energy analysis and molecular dynamics simulations were conducted towards understanding the mechanisms by which the compounds bind to PfHsp70. The molecular docking results revealed ligand flexibilities, conformations and positions of key amino acid residues and protein-ligand interactions as crucial factors accounting for selective inhibition of Hsp70. The simulation results also suggest protein-ligand van der Waals forces as the driving force guiding the interaction of these compounds with PfHsp70. Of the two compounds, UAA and IMA bound to PfHsp70 within the micromolar range based on surface plasmon resonance (SPR) based binding assay. Our findings pave way for future rational design of new selective compounds targeting PfHsp70.
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Affiliation(s)
- Francis Opoku
- Department of Chemical Sciences (formerly Department of Applied Chemistry), University of Johannesburg, Doornfontein Campus, P.O. Box 17011, Johannesburg, 2028, South Africa
- Department of Chemistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Penny Govender
- Department of Chemical Sciences (formerly Department of Applied Chemistry), University of Johannesburg, Doornfontein Campus, P.O. Box 17011, Johannesburg, 2028, South Africa
| | - Addmore Shonhai
- Department of Biochemistry & Microbiology, University of Venda, Thohoyandou, South Africa
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4
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Muthelo T, Mulaudzi V, Netshishivhe M, Dongola TH, Kok M, Makumire S, de Villiers M, Burger A, Zininga T, Shonhai A. Inhibition of Plasmodium falciparum Hsp70-Hop partnership by 2-phenylthynesulfonamide. Front Mol Biosci 2022; 9:947203. [PMID: 36177352 PMCID: PMC9513230 DOI: 10.3389/fmolb.2022.947203] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
Plasmodium falciparum Hsp70-1 (PfHsp70-1; PF3D7_0818900) and PfHsp90 (PF3D7_0708400) are essential cytosol localized chaperones of the malaria parasite. The two chaperones form a functional complex via the adaptor protein, Hsp90-Hsp70 organizing protein (PfHop [PF3D7_1434300]), which modulates the interaction of PfHsp70-1 and PfHsp90 through its tetracopeptide repeat (TPR) domains in a nucleotide-dependent fashion. On the other hand, PfHsp70-1 and PfHsp90 possess C-terminal EEVD and MEEVD motifs, respectively, which are crucial for their interaction with PfHop. By coordinating the cooperation of these two chaperones, PfHop plays an important role in the survival of the malaria parasite. 2-Phenylthynesulfonamide (PES) is a known anti-cancer agent whose mode of action is to inhibit Hsp70 function. In the current study, we explored the antiplasmodial activity of PES and investigated its capability to target the functions of PfHsp70-1 and its co-chaperone, PfHop. PES exhibited modest antiplasmodial activity (IC50 of 38.7 ± 0.7 µM). Furthermore, using surface plasmon resonance (SPR) analysis, we demonstrated that PES was capable of binding recombinant forms of both PfHsp70-1 and PfHop. Using limited proteolysis and intrinsic fluorescence-based analysis, we showed that PES induces conformational changes in PfHsp70-1 and PfHop. In addition, we demonstrated that PES inhibits the chaperone function of PfHsp70-1. Consequently, PES abrogated the association of the two proteins in vitro. Our study findings contribute to the growing efforts to expand the arsenal of potential antimalarial compounds in the wake of growing parasite resistance against currently used drugs.
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Affiliation(s)
- Tshifhiwa Muthelo
- Department of Biochemistry & Microbiology, University of Venda, Thohoyandou, South Africa
| | - Vhahangwele Mulaudzi
- Department of Biochemistry & Microbiology, University of Venda, Thohoyandou, South Africa
| | - Munei Netshishivhe
- Department of Biochemistry & Microbiology, University of Venda, Thohoyandou, South Africa
| | | | - Michelle Kok
- Department of Biochemistry, Stellenbosch University, Matieland, South Africa
| | - Stanley Makumire
- Department of Biochemistry & Microbiology, University of Venda, Thohoyandou, South Africa
- Structural Biology Research Unit, Department of Integrative Biomedical Sciences, University of Cape Town, Cape Town, South Africa
| | | | - Adélle Burger
- Department of Biochemistry & Microbiology, University of Venda, Thohoyandou, South Africa
| | - Tawanda Zininga
- Department of Biochemistry & Microbiology, University of Venda, Thohoyandou, South Africa
- Department of Biochemistry, Stellenbosch University, Matieland, South Africa
| | - Addmore Shonhai
- Department of Biochemistry & Microbiology, University of Venda, Thohoyandou, South Africa
- *Correspondence: Addmore Shonhai,
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5
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Daniyan MO, Fisusi FA, Adeoye OB. Neurotransmitters and molecular chaperones interactions in cerebral malaria: Is there a missing link? Front Mol Biosci 2022; 9:965569. [PMID: 36090033 PMCID: PMC9451049 DOI: 10.3389/fmolb.2022.965569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 07/28/2022] [Indexed: 12/02/2022] Open
Abstract
Plasmodium falciparum is responsible for the most severe and deadliest human malaria infection. The most serious complication of this infection is cerebral malaria. Among the proposed hypotheses that seek to explain the manifestation of the neurological syndrome in cerebral malaria is the vascular occlusion/sequestration/mechanic hypothesis, the cytokine storm or inflammatory theory, or a combination of both. Unfortunately, despite the increasing volume of scientific information on cerebral malaria, our understanding of its pathophysiologic mechanism(s) is still very limited. In a bid to maintain its survival and development, P. falciparum exports a large number of proteins into the cytosol of the infected host red blood cell. Prominent among these are the P. falciparum erythrocytes membrane protein 1 (PfEMP1), P. falciparum histidine-rich protein II (PfHRP2), and P. falciparum heat shock proteins 70-x (PfHsp70-x). Functional activities and interaction of these proteins with one another and with recruited host resident proteins are critical factors in the pathology of malaria in general and cerebral malaria in particular. Furthermore, several neurological impairments, including cognitive, behavioral, and motor dysfunctions, are known to be associated with cerebral malaria. Also, the available evidence has implicated glutamate and glutamatergic pathways, coupled with a resultant alteration in serotonin, dopamine, norepinephrine, and histamine production. While seeking to improve our understanding of the pathophysiology of cerebral malaria, this article seeks to explore the possible links between host/parasite chaperones, and neurotransmitters, in relation to other molecular players in the pathology of cerebral malaria, to explore such links in antimalarial drug discovery.
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Affiliation(s)
- Michael Oluwatoyin Daniyan
- Department of Pharmacology, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
- *Correspondence: Michael Oluwatoyin Daniyan, ,
| | - Funmilola Adesodun Fisusi
- Drug Research and Production Unit, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
| | - Olufunso Bayo Adeoye
- Department of Biochemistry, Benjamin S. Carson (Snr.) College of Medicine, Babcock University, Ilishan-Remo, Ogun State, Nigeria
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6
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Barth J, Schach T, Przyborski JM. HSP70 and their co-chaperones in the human malaria parasite P. falciparum and their potential as drug targets. Front Mol Biosci 2022; 9:968248. [PMID: 35992276 PMCID: PMC9388776 DOI: 10.3389/fmolb.2022.968248] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 07/04/2022] [Indexed: 11/13/2022] Open
Abstract
As part of their life-cycle, malaria parasites undergo rapid cell multiplication and division, with one parasite giving rise to over 20 new parasites within the course of 48 h. To support this, the parasite has an extremely high metabolic rate and level of protein biosynthesis. Underpinning these activities, the parasite encodes a number of chaperone/heat shock proteins, belonging to various families. Research over the past decade has revealed that these proteins are involved in a number of essential processes within the parasite, or within the infected host cell. Due to this, these proteins are now being viewed as potential targets for drug development, and we have begun to characterize their properties in more detail. In this article we summarize the current state of knowledge about one particular chaperone family, that of the HSP70, and highlight their importance, function, and potential co-chaperone interactions. This is then discussed with regard to the suitability of these proteins and interactions for drug development.
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7
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Hsp90 and Associated Co-Chaperones of the Malaria Parasite. Biomolecules 2022; 12:biom12081018. [PMID: 35892329 PMCID: PMC9332011 DOI: 10.3390/biom12081018] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 07/16/2022] [Accepted: 07/17/2022] [Indexed: 12/14/2022] Open
Abstract
Heat shock protein 90 (Hsp90) is one of the major guardians of cellular protein homeostasis, through its specialized molecular chaperone properties. While Hsp90 has been extensively studied in many prokaryotic and higher eukaryotic model organisms, its structural, functional, and biological properties in parasitic protozoans are less well defined. Hsp90 collaborates with a wide range of co-chaperones that fine-tune its protein folding pathway. Co-chaperones play many roles in the regulation of Hsp90, including selective targeting of client proteins, and the modulation of its ATPase activity, conformational changes, and post-translational modifications. Plasmodium falciparum is responsible for the most lethal form of human malaria. The survival of the malaria parasite inside the host and the vector depends on the action of molecular chaperones. The major cytosolic P. falciparum Hsp90 (PfHsp90) is known to play an essential role in the development of the parasite, particularly during the intra-erythrocytic stage in the human host. Although PfHsp90 shares significant sequence and structural similarity with human Hsp90, it has several major structural and functional differences. Furthermore, its co-chaperone network appears to be substantially different to that of the human host, with the potential absence of a key homolog. Indeed, PfHsp90 and its interface with co-chaperones represent potential drug targets for antimalarial drug discovery. In this review, we critically summarize the current understanding of the properties of Hsp90, and the associated co-chaperones of the malaria parasite.
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8
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Blatch GL. Plasmodium falciparum Molecular Chaperones: Guardians of the Malaria Parasite Proteome and Renovators of the Host Proteome. Front Cell Dev Biol 2022; 10:921739. [PMID: 35652103 PMCID: PMC9149364 DOI: 10.3389/fcell.2022.921739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 04/28/2022] [Indexed: 11/13/2022] Open
Abstract
Plasmodium falciparum is a unicellular protozoan parasite and causative agent of the most severe form of malaria in humans. The malaria parasite has had to develop sophisticated mechanisms to preserve its proteome under the changing stressful conditions it confronts, particularly when it invades host erythrocytes. Heat shock proteins, especially those that function as molecular chaperones, play a key role in protein homeostasis (proteostasis) of P. falciparum. Soon after invading erythrocytes, the malaria parasite exports a large number of proteins including chaperones, which are responsible for remodeling the infected erythrocyte to enable its survival and pathogenesis. The infected host cell has parasite-resident and erythrocyte-resident chaperones, which appear to play a vital role in the folding and functioning of P. falciparum proteins and potentially host proteins. This review critiques the current understanding of how the major chaperones, particularly the Hsp70 and Hsp40 (or J domain proteins, JDPs) families, contribute to proteostasis of the malaria parasite-infected erythrocytes.
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Affiliation(s)
- Gregory L Blatch
- The Vice Chancellery, The University of Notre Dame Australia, Fremantle, WA, Australia.,Biomedical Biotechnology Research Unit, Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, South Africa.,Biomedical Research and Drug Discovery Research Group, Faculty of Health Sciences, Higher Colleges of Technology, Sharjah, United Arab Emirates
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9
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Daniyan MO. Heat Shock Proteins as Targets for Novel Antimalarial Drug Discovery. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1340:205-236. [PMID: 34569027 DOI: 10.1007/978-3-030-78397-6_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Plasmodium falciparum, the parasitic agent that is responsible for a severe and dangerous form of human malaria, has a history of long years of cohabitation with human beings with attendant negative consequences. While there have been some gains in the fight against malaria through the application of various control measures and the use of chemotherapeutic agents, and despite the global decline in malaria cases and associated deaths, the continual search for new and effective therapeutic agents is key to achieving sustainable development goals. An important parasite survival strategy, which is also of serious concern to the scientific community, is the rate at which the parasites continually develop resistance to drugs. Among the key players in the parasite's ability to develop resistance, maintain cellular integrity, and survives within an unusual environment of the red blood cells are the molecular chaperones of the heat shock proteins (HSP) family. HSPs constitute a novel avenue for antimalarial drug discovery and by exploring their ubiquitous nature and multifunctional activities, they may be suitable targets for the discovery of multi-targets antimalarial drugs, needed to fight incessant drug resistance. In this chapter, features of selected families of plasmodial HSPs that can be exploited in drug discovery are presented. Also, known applications of HSPs in small molecule screening, their potential usefulness in high throughput drug screening, as well as possible challenges are highlighted.
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Affiliation(s)
- Michael Oluwatoyin Daniyan
- Department of Pharmacology, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria.
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10
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The Role of Hsp70s in the Development and Pathogenicity of Plasmodium falciparum. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021. [PMID: 34569021 DOI: 10.1007/978-3-030-78397-6_3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
The main agent of human malaria, the protozoa, Plasmodium falciparum is known to infect liver cells, subsequently invading the host erythrocyte, leading to the manifestation of clinical outcomes of the disease. As part of its survival in the human host, P. falciparum employs several heat shock protein (Hsp) families whose primary purpose is to ensure cytoprotection through their molecular chaperone role. The parasite expresses six Hsp70s that localise to various subcellular organelles of the parasite, with one, PfHsp70-x, being exported to the infected human erythrocyte. The role of these Hsp70s in the survival and pathogenicity of malaria has received immense research attention. Several studies have reported on their structure-function features, network partnerships, and elucidation of their potential substrates. Apart from their role in cytoprotection and pathogenicity, Hsp70s are implicated in antimalarial drug resistance. As such, they are deemed potential antimalarial drug candidates, especially suited for co-targeting in combination therapies. In addition, Hsp70 is implicated in host immune modulation. The current report highlights the various structure-function features of these proteins, their roles in the development of malaria, current and prospective efforts being employed towards targeting them in malaria intervention efforts.
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11
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Salomane N, Pooe OJ, Simelane MBC. Iso-mukaadial acetate and ursolic acid acetate inhibit the chaperone activity of Plasmodium falciparum heat shock protein 70-1. Cell Stress Chaperones 2021; 26:685-693. [PMID: 34023985 PMCID: PMC8275760 DOI: 10.1007/s12192-021-01212-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 05/04/2021] [Accepted: 05/10/2021] [Indexed: 10/21/2022] Open
Abstract
Plasmodium falciparum is the most lethal malaria parasite. The present study investigates the interaction capabilities of select plant derivatives, iso-mukaadial acetate (IMA) and ursolic acid acetate (UAA), against P. falciparum Hsp70-1 (PfHsp70-1) using in vitro approaches. PfHsp70-1 facilitates protein folding in the parasite and is deemed a prospective antimalarial drug target. Recombinant PfHsp70-1 protein was expressed in E. coli BL21 cells and homogeneously purified by affinity chromatography. The interaction between the compounds and PfHsp70-1 was evaluated using malate dehydrogenase (MDH), and luciferase aggregation assay, ATPase activity assay, and Fourier transform infrared (FTIR). PfHsp70-1 prevented the heat-induced aggregation of MDH and luciferase. However, the PfHsp70-1 chaperone role was inhibited by IMA or UAA, leading to both MDH and luciferase's thermal aggregation. The basal ATPase activity of PfHsp70-1 (0.121 nmol/min/mg) was closer to UAA (0.131 nmol/min/mg) (p = 0.0675) at 5 mM compound concentration, suggesting that UAA has no effect on PfHsp70-1 ATPase activity. However, ATPase activity inhibition was similar between IMA (0.068 nmol/min/mg) (p < 0.0001) and polymyxin B (0.083 nmol/min/mg) (p < 0.0001). The lesser the Pi values, the lesser ATP hydrolysis observed due to compound binding to the ATPase domain. FTIR spectra analysis of IMA and UAA resulted in PfHsp70-1 structural alteration for β-sheets shifting the amide I band from 1637 cm-1 to 1639 cm-1, and for α-helix from 1650 cm-1 to 1652 cm-1, therefore depicting secondary structural changes with an increase in secondary structure percentage suggesting that these compounds interact with PfHsp70-1.
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Affiliation(s)
- Nicolaas Salomane
- Department of Biochemistry, Faculty of Science, University of Johannesburg, Johannesburg, 2006, South Africa
| | - Ofentse J Pooe
- Discipline of Biochemistry, School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, 4000, South Africa
| | - Mthokozisi B C Simelane
- Department of Biochemistry, Faculty of Science, University of Johannesburg, Johannesburg, 2006, South Africa.
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12
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Chakafana G, Spracklen TF, Kamuli S, Zininga T, Shonhai A, Ntusi NAB, Sliwa K. Heat Shock Proteins: Potential Modulators and Candidate Biomarkers of Peripartum Cardiomyopathy. Front Cardiovasc Med 2021; 8:633013. [PMID: 34222357 PMCID: PMC8241919 DOI: 10.3389/fcvm.2021.633013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 05/06/2021] [Indexed: 12/31/2022] Open
Abstract
Peripartum cardiomyopathy (PPCM) is a potentially life-threatening condition in which heart failure and systolic dysfunction occur late in pregnancy or within months following delivery. To date, no reliable biomarkers or therapeutic interventions for the condition exist, thus necessitating an urgent need for identification of novel PPCM drug targets and candidate biomarkers. Leads for novel treatments and biomarkers are therefore being investigated worldwide. Pregnancy is generally accompanied by dramatic hemodynamic changes, including a reduced afterload and a 50% increase in cardiac output. These increased cardiac stresses during pregnancy potentially impair protein folding processes within the cardiac tissue. The accumulation of misfolded proteins results in increased toxicity and cardiac insults that trigger heart failure. Under stress conditions, molecular chaperones such as heat shock proteins (Hsps) play crucial roles in maintaining cellular proteostasis. Here, we critically assess the potential role of Hsps in PPCM. We further predict specific associations between the Hsp types Hsp70, Hsp90 and small Hsps with several proteins implicated in PPCM pathophysiology. Furthermore, we explore the possibility of select Hsps as novel candidate PPCM biomarkers and drug targets. A better understanding of how these Hsps modulate PPCM pathogenesis holds promise in improving treatment, prognosis and management of the condition, and possibly other forms of acute heart failure.
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Affiliation(s)
- Graham Chakafana
- Department of Medicine, Faculty of Health Sciences, Cape Heart Institute, University of Cape Town, Cape Town, South Africa.,Division of Cardiology, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Timothy F Spracklen
- Department of Medicine, Faculty of Health Sciences, Cape Heart Institute, University of Cape Town, Cape Town, South Africa.,Division of Cardiology, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Stephen Kamuli
- Department of Medicine, Faculty of Health Sciences, Cape Heart Institute, University of Cape Town, Cape Town, South Africa.,Division of Cardiology, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Tawanda Zininga
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
| | - Addmore Shonhai
- Department of Biochemistry, University of Venda, Thohoyandou, South Africa
| | - Ntobeko A B Ntusi
- Department of Medicine, Faculty of Health Sciences, Cape Heart Institute, University of Cape Town, Cape Town, South Africa.,Division of Cardiology, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.,Cape Universities Body Imaging Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Karen Sliwa
- Department of Medicine, Faculty of Health Sciences, Cape Heart Institute, University of Cape Town, Cape Town, South Africa.,Division of Cardiology, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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Abstract
It gives me great pleasure to have the opportunity to introduce myself to the readers of Biophysical Reviews as part of the 'meet the editors' series. What follows is a mini-autobiography of my life as it relates to my scientific career and research.
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Affiliation(s)
- Addmore Shonhai
- Department of Biochemistry, University of Venda, Private Bag X5050, Thohoyandou, 0950 South Africa
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Kayamba F, Malimabe T, Ademola IK, Pooe OJ, Kushwaha ND, Mahlalela M, van Zyl RL, Gordon M, Mudau PT, Zininga T, Shonhai A, Nyamori VO, Karpoormath R. Design and synthesis of quinoline-pyrimidine inspired hybrids as potential plasmodial inhibitors. Eur J Med Chem 2021; 217:113330. [PMID: 33744688 DOI: 10.1016/j.ejmech.2021.113330] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 02/18/2021] [Accepted: 02/24/2021] [Indexed: 01/16/2023]
Abstract
Presently, artemisinin-based combination therapy (ACT) is the first-line therapy of Plasmodium falciparum malaria. With the emergence of malaria parasites that are resistant to ACT, alternative antimalarial therapies are urgently needed. In line with this, we designed and synthesised a series of novel N-(7-chloroquinolin-4-yl)-N'-(4,6-diphenylpyrimidin-2-yl)alkanediamine hybrids (6a-7c) and evaluated their inhibitory activity against the NF54 chloroquine-susceptible strain as a promising class of antimalarial compounds. The antiplasmodial screening revealed that seven analogues showed promising to good activity with half-maximal inhibitory concentration (IC50) = 0.32 μM-4.30 μM. Compound 7a with 1,4-diamine butyl linker and 4-hydroxyl phenyl on fourth and sixth position of pyrimidine core showed the most prominent activity with an IC50 value of 0.32 ± 0.06 μM, with a favourable safety profile of 9.79 to human kidney epithelial (HEK293) cells. The remaining six analogues showed moderate activity with IC50 values ranging from 7.50 μM to 83.01 μM. We further investigated the binding affinities of the molecules to two essential cytosolic P. falciparum heat shock protein 70 homologues; PfHsp70-1 and PfHsp70-z. Compound 7a exhibited the highest binding affinity for both PfHsp70s with KD in a lower nanomolar range (4.4-11.4 nM). Furthermore, molecular docking revealed that compounds 6, 6k, 7b and 7a exhibited better fitness in PfHsp70-1 with compound 7a showing the highest and lowest binding scores of -9.8 kcal/mol. Therefore, we speculate that PfHsp70-1 is one of the targets of these inhibitors. The bioisoteric replacement of the groups at phenyl ring at the fourth and sixth position of the pyrimidine core had a constructive association with antiplasmodial activity. The promising antiplasmodial activity of the synthesised analogues illustrates how crucial molecular hybridisation is as a strategy in the development of quinoline-pyrimidine hybrids as prospective antiprotozoal agents.
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Affiliation(s)
- Francis Kayamba
- Department of Pharmaceutical Chemistry, College of Health Sciences, University of KwaZulu-Natal, Durban, 4000, South Africa
| | - Teboho Malimabe
- Pharmacology Division, Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, 2193, South Africa; WITS Research Institute for Malaria (WRIM), Faculty of Health Sciences, University of Witwatersrand, Johannesburg, 2193, South Africa
| | - Idowu Kehinde Ademola
- School of Laboratory Medicine and Medical Sciences, College of Health Science, University of KwaZulu-Natal, Durban, 4000, South Africa
| | - Ofentse Jacob Pooe
- Discipline of Biochemistry, School of Life Sciences, University of KwaZulu-Natal, Durban, 4000, South Africa
| | - Narva Deshwar Kushwaha
- Department of Pharmaceutical Chemistry, College of Health Sciences, University of KwaZulu-Natal, Durban, 4000, South Africa
| | - Mavela Mahlalela
- Department of Pharmaceutical Chemistry, College of Health Sciences, University of KwaZulu-Natal, Durban, 4000, South Africa
| | - Robyn L van Zyl
- Pharmacology Division, Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, 2193, South Africa; WITS Research Institute for Malaria (WRIM), Faculty of Health Sciences, University of Witwatersrand, Johannesburg, 2193, South Africa
| | - Michelle Gordon
- School of Laboratory Medicine and Medical Sciences, College of Health Science, University of KwaZulu-Natal, Durban, 4000, South Africa
| | - Pertunia T Mudau
- Department of Biochemistry University of Venda, School of Mathematical and Natural Sciences, Thohoyandou, 0950, South Africa
| | - Tawanda Zininga
- Department of Biochemistry University of Venda, School of Mathematical and Natural Sciences, Thohoyandou, 0950, South Africa; Department of Biochemistry, Stellenbosch University, Stellenbosch, 7600, South Africa
| | - Addmore Shonhai
- Department of Biochemistry, Stellenbosch University, Stellenbosch, 7600, South Africa
| | - Vincent O Nyamori
- School of Chemistry and Physics, University of KwaZulu-Natal, Westville Campus, Durban, 4000, South Africa
| | - Rajshekhar Karpoormath
- Department of Pharmaceutical Chemistry, College of Health Sciences, University of KwaZulu-Natal, Durban, 4000, South Africa.
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15
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Makumire S, Dongola TH, Chakafana G, Tshikonwane L, Chauke CT, Maharaj T, Zininga T, Shonhai A. Mutation of GGMP Repeat Segments of Plasmodium falciparum Hsp70-1 Compromises Chaperone Function and Hop Co-Chaperone Binding. Int J Mol Sci 2021; 22:ijms22042226. [PMID: 33672387 PMCID: PMC7926355 DOI: 10.3390/ijms22042226] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/02/2021] [Accepted: 02/09/2021] [Indexed: 12/11/2022] Open
Abstract
Parasitic organisms especially those of the Apicomplexan phylum, harbour a cytosol localised canonical Hsp70 chaperone. One of the defining features of this protein is the presence of GGMP repeat residues sandwiched between α-helical lid and C-terminal EEVD motif. The role of the GGMP repeats of Hsp70s remains unknown. In the current study, we introduced GGMP mutations in the cytosol localised Hsp70-1 of Plasmodium falciparum (PfHsp70-1) and a chimeric protein (KPf), constituted by the ATPase domain of E. coli DnaK fused to the C-terminal substrate binding domain of PfHsp70-1. A complementation assay conducted using E. coli dnaK756 cells demonstrated that the GGMP motif was essential for chaperone function of the chimeric protein, KPf. Interestingly, insertion of GGMP motif of PfHsp70-1 into DnaK led to a lethal phenotype in E. coli dnaK756 cells exposed to elevated growth temperature. Using biochemical and biophysical assays, we established that the GGMP motif accounts for the elevated basal ATPase activity of PfHsp70-1. Furthermore, we demonstrated that this motif is important for interaction of the chaperone with peptide substrate and a co-chaperone, PfHop. Our findings suggest that the GGMP may account for both the specialised chaperone function and reportedly high catalytic efficiency of PfHsp70-1.
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Affiliation(s)
- Stanley Makumire
- Department of Biochemistry, University of Venda, Private Bag X5050, Thohoyandou 0950, South Africa; (S.M.); (T.H.D.); (G.C.); (L.T.); (C.T.C.); (T.Z.)
- Structural Biology Research Unit, Department of Integrative Biomedical Sciences, University of Cape Town, Observatory 7925, South Africa
| | - Tendamudzimu Harmfree Dongola
- Department of Biochemistry, University of Venda, Private Bag X5050, Thohoyandou 0950, South Africa; (S.M.); (T.H.D.); (G.C.); (L.T.); (C.T.C.); (T.Z.)
| | - Graham Chakafana
- Department of Biochemistry, University of Venda, Private Bag X5050, Thohoyandou 0950, South Africa; (S.M.); (T.H.D.); (G.C.); (L.T.); (C.T.C.); (T.Z.)
- Department of Medicine, University of Cape Town, Faculty of Health Sciences, Observatory, Cape Town 7925, South Africa
| | - Lufuno Tshikonwane
- Department of Biochemistry, University of Venda, Private Bag X5050, Thohoyandou 0950, South Africa; (S.M.); (T.H.D.); (G.C.); (L.T.); (C.T.C.); (T.Z.)
| | - Cecilia Tshikani Chauke
- Department of Biochemistry, University of Venda, Private Bag X5050, Thohoyandou 0950, South Africa; (S.M.); (T.H.D.); (G.C.); (L.T.); (C.T.C.); (T.Z.)
| | - Tarushai Maharaj
- Department of Biochemistry, Stellenbosch University, Stellenbosch 7600, South Africa;
| | - Tawanda Zininga
- Department of Biochemistry, University of Venda, Private Bag X5050, Thohoyandou 0950, South Africa; (S.M.); (T.H.D.); (G.C.); (L.T.); (C.T.C.); (T.Z.)
- Department of Biochemistry, Stellenbosch University, Stellenbosch 7600, South Africa;
| | - Addmore Shonhai
- Department of Biochemistry, University of Venda, Private Bag X5050, Thohoyandou 0950, South Africa; (S.M.); (T.H.D.); (G.C.); (L.T.); (C.T.C.); (T.Z.)
- Correspondence: ; Tel.: +27-15962-8723
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16
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Structural-functional diversity of malaria parasite's PfHSP70-1 and PfHSP40 chaperone pair gives an edge over human orthologs in chaperone-assisted protein folding. Biochem J 2021; 477:3625-3643. [PMID: 32893851 DOI: 10.1042/bcj20200434] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/02/2020] [Accepted: 09/07/2020] [Indexed: 12/13/2022]
Abstract
Plasmodium falciparum, the human malaria parasite harbors a metastable proteome which is vulnerable to proteotoxic stress conditions encountered during its lifecycle. How parasite's chaperone machinery is able to maintain its aggregation-prone proteome in functional state, is poorly understood. As HSP70-40 system forms the central hub in cellular proteostasis, we investigated the protein folding capacity of PfHSP70-1 and PfHSP40 chaperone pair and compared it with human orthologs (HSPA1A and DNAJA1). Despite the structural similarity, we observed that parasite chaperones and their human orthologs exhibit striking differences in conformational dynamics. Comprehensive biochemical investigations revealed that PfHSP70-1 and PfHSP40 chaperone pair has better protein folding, aggregation inhibition, oligomer remodeling and disaggregase activities than their human orthologs. Chaperone-swapping experiments suggest that PfHSP40 can also efficiently cooperate with human HSP70 to facilitate the folding of client-substrate. SPR-derived kinetic parameters reveal that PfHSP40 has higher binding affinity towards unfolded substrate than DNAJA1. Interestingly, the observed slow dissociation rate of PfHSP40-substrate interaction allows PfHSP40 to maintain the substrate in folding-competent state to minimize its misfolding. Structural investigation through small angle x-ray scattering gave insights into the conformational architecture of PfHSP70-1 (monomer), PfHSP40 (dimer) and their complex. Overall, our data suggest that the parasite has evolved functionally diverged and efficient chaperone machinery which allows the human malaria parasite to survive in hostile conditions. The distinct allosteric landscapes and interaction kinetics of plasmodial chaperones open avenues for the exploration of small-molecule based antimalarial interventions.
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Shonhai A, Blatch GL. Heat Shock Proteins of Malaria: Highlights and Future Prospects. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1340:237-246. [PMID: 34569028 DOI: 10.1007/978-3-030-78397-6_10] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The deadliest malaria parasite of humans, Plasmodium falciparum, is an obligate parasite that has had to develop mechanisms for survival under the unfavourable conditions it confronts within host cells. The chapters in the book "Heat Shock Proteins of Malaria" provide a critique of the evidence that heat shock proteins (Hsps) play a key role in the survival of P. falciparum in host cells. The role of the plasmodial Hsp arsenal is not limited to the protection of the parasite cell (largely through their role as molecular chaperones), as some of these proteins also promote the pathological development of malaria. This is largely due to the export of a large number of these proteins into the infected erythrocyte cytosol. Although P. falciparum erythrocyte membrane protein 1 (PfEMP1) is the main virulence factor for the malaria parasite, some of the exported plasmodial Hsps appear to augment parasite virulence. While this book largely delves into experimentally validated information on the role of Hsps in the development and pathogenicity of malaria, some of the information is based on hypotheses yet to be fully tested. Therefore, here we highlight what we know to be definite roles of plasmodial Hsps. Furthermore, we distill information that could provide practical insights on the options available for future research directions, including interventions against malaria that may target the role of Hsps in the development of the disease.
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Affiliation(s)
- Addmore Shonhai
- Department of Biochemistry, University of Venda, Thohoyandou, South Africa.
| | - Gregory L Blatch
- The Vice Chancellery, The University of Notre Dame Australia, Fremantle, WA, Australia. .,Biomedical Biotechnology Research Unit, Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, South Africa. .,The Institute of Immunology and Infectious Diseases, Murdoch University, Murdoch, WA, Australia. .,Faculty of Health Sciences, Higher Colleges of Technology, Sharjah, United Arab Emirates.
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18
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Makhoba XH, Viegas C, Mosa RA, Viegas FPD, Pooe OJ. Potential Impact of the Multi-Target Drug Approach in the Treatment of Some Complex Diseases. DRUG DESIGN DEVELOPMENT AND THERAPY 2020; 14:3235-3249. [PMID: 32884235 PMCID: PMC7440888 DOI: 10.2147/dddt.s257494] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 07/08/2020] [Indexed: 12/16/2022]
Abstract
It is essential to acknowledge the efforts made thus far to manage or eliminate various disease burden faced by humankind. However, the rising global trends of the so-called incurable diseases continue to put pressure on Pharma industries and other drug discovery platforms. In the past, drugs with more than one target were deemed as undesirable options with interest being on the one-drug-single target. Despite the successes of the single-target drugs, it is currently beyond doubt that these drugs have limited efficacy against complex diseases in which the pathogenesis is dependent on a set of biochemical events and several bioreceptors operating concomitantly. Different approaches have thus been proposed to come up with effective drugs to combat even the complex diseases. In the past, the focus was on producing drugs from screening plant compounds; today, we talk about combination therapy and multi-targeting drugs. The multi-target drugs have recently attracted much attention as promising tools to fight against most challenging diseases, and thus a new research focus area. This review will discuss the potential impact of multi-target drug approach on various complex diseases with focus on malaria, tuberculosis (TB), diabetes and neurodegenerative diseases as the main representatives of multifactorial diseases. We will also discuss alternative ideas to solve the current problems bearing in mind the fourth industrial revolution on drug discovery.
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Affiliation(s)
- Xolani H Makhoba
- Department of Biochemistry, Genetics and Microbiology, Division of Biochemistry, University of Pretoria, Hatfield, South Africa
| | - Claudio Viegas
- Laboratory of Research in Medicinal Chemistry (PeQuiM), Institute of Chemistry, Federal University of Alfenas, Alfenas, MG, Brazil
| | - Rebamang A Mosa
- Department of Biochemistry, Genetics and Microbiology, Division of Biochemistry, University of Pretoria, Hatfield, South Africa
| | - Flávia P D Viegas
- Laboratory of Research in Medicinal Chemistry (PeQuiM), Institute of Chemistry, Federal University of Alfenas, Alfenas, MG, Brazil
| | - Ofentse J Pooe
- Discipline of Biochemistry, School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
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19
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Lebepe CM, Matambanadzo PR, Makhoba XH, Achilonu I, Zininga T, Shonhai A. Comparative Characterization of Plasmodium falciparum Hsp70-1 Relative to E. coli DnaK Reveals the Functional Specificity of the Parasite Chaperone. Biomolecules 2020; 10:biom10060856. [PMID: 32512819 PMCID: PMC7356358 DOI: 10.3390/biom10060856] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/21/2020] [Accepted: 06/01/2020] [Indexed: 12/20/2022] Open
Abstract
Hsp70 is a conserved molecular chaperone. How Hsp70 exhibits specialized functions across species remains to be understood. Plasmodium falciparum Hsp70-1 (PfHsp70-1) and Escherichia coli DnaK are cytosol localized molecular chaperones that are important for the survival of these two organisms. In the current study, we investigated comparative structure-function features of PfHsp70-1 relative to DnaK and a chimeric protein, KPf, constituted by the ATPase domain of DnaK and the substrate binding domain (SBD) of PfHsp70-1. Recombinant forms of the three Hsp70s exhibited similar secondary and tertiary structural folds. However, compared to DnaK, both KPf and PfHsp70-1 were more stable to heat stress and exhibited higher basal ATPase activity. In addition, PfHsp70-1 preferentially bound to asparagine rich peptide substrates, as opposed to DnaK. Recombinant P. falciparum adenosylmethionine decarboxylase (PfAdoMetDC) co-expressed in E. coli with either KPf or PfHsp70-1 was produced as a fully folded product. Co-expression of PfAdoMetDC with heterologous DnaK in E. coli did not promote folding of the former. However, a combination of supplementary GroEL plus DnaK improved folding of PfAdoMetDC. These findings demonstrated that the SBD of PfHsp70-1 regulates several functional features of the protein and that this molecular chaperone is tailored to facilitate folding of plasmodial proteins.
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Affiliation(s)
- Charity Mekgwa Lebepe
- Department of Biochemistry, School of Mathematical & Natural Sciences, University of Venda, Thohoyandou 0950, South Africa; (C.M.L.); (P.R.M.); (T.Z.)
| | - Pearl Rutendo Matambanadzo
- Department of Biochemistry, School of Mathematical & Natural Sciences, University of Venda, Thohoyandou 0950, South Africa; (C.M.L.); (P.R.M.); (T.Z.)
| | - Xolani Henry Makhoba
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria 0028, South Africa;
| | - Ikechukwu Achilonu
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050, South Africa;
| | - Tawanda Zininga
- Department of Biochemistry, School of Mathematical & Natural Sciences, University of Venda, Thohoyandou 0950, South Africa; (C.M.L.); (P.R.M.); (T.Z.)
- Department of Biochemistry, Stellenbosch University, Stellenbosch 7602, South Africa
| | - Addmore Shonhai
- Department of Biochemistry, School of Mathematical & Natural Sciences, University of Venda, Thohoyandou 0950, South Africa; (C.M.L.); (P.R.M.); (T.Z.)
- Correspondence:
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20
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Makumire S, Zininga T, Vahokoski J, Kursula I, Shonhai A. Biophysical analysis of Plasmodium falciparum Hsp70-Hsp90 organising protein (PfHop) reveals a monomer that is characterised by folded segments connected by flexible linkers. PLoS One 2020; 15:e0226657. [PMID: 32343703 PMCID: PMC7188212 DOI: 10.1371/journal.pone.0226657] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 04/03/2020] [Indexed: 12/20/2022] Open
Abstract
Plasmodium falciparum causes the most lethal form of malaria. The cooperation of heat shock protein (Hsp) 70 and 90 is thought to facilitate folding of select group of cellular proteins that are crucial for cyto-protection and development of the parasites. Hsp70 and Hsp90 are brought into a functional complex that allows substrate exchange by stress inducible protein 1 (STI1), also known as Hsp70-Hsp90 organising protein (Hop). P. falciparum Hop (PfHop) co-localises and occurs in complex with the parasite cytosolic chaperones, PfHsp70-1 and PfHsp90. Here, we characterised the structure of recombinant PfHop using synchrotron radiation circular dichroism (SRCD) and small-angle X-ray scattering. Structurally, PfHop is a monomeric, elongated but folded protein, in agreement with its predicted TPR domain structure. Using SRCD, we established that PfHop is unstable at temperatures higher than 40°C. This suggests that PfHop is less stable at elevated temperatures compared to its functional partner, PfHsp70-1, that is reportedly stable at temperatures as high as 80°C. These findings contribute towards our understanding of the role of the Hop-mediated functional partnership between Hsp70 and Hsp90.
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Affiliation(s)
- Stanley Makumire
- Department of Biochemistry, School of Mathematical & Natural Sciences, University of Venda, Thohoyandou, South Africa
| | - Tawanda Zininga
- Department of Biochemistry, School of Mathematical & Natural Sciences, University of Venda, Thohoyandou, South Africa
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
| | - Juha Vahokoski
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Inari Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Biocenter Oulu & Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Addmore Shonhai
- Department of Biochemistry, School of Mathematical & Natural Sciences, University of Venda, Thohoyandou, South Africa
- * E-mail:
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Screening for Small Molecule Modulators of Trypanosoma brucei Hsp70 Chaperone Activity Based upon Alcyonarian Coral-Derived Natural Products. Mar Drugs 2020; 18:md18020081. [PMID: 32012664 PMCID: PMC7074166 DOI: 10.3390/md18020081] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 01/14/2020] [Accepted: 01/16/2020] [Indexed: 11/17/2022] Open
Abstract
The Trypanosoma brucei Hsp70/J-protein machinery plays an essential role in survival, differentiation, and pathogenesis of the protozoan parasite, and is an emerging target against African Trypanosomiasis. This study evaluated a set of small molecules, inspired by the malonganenones and nuttingins, as modulators of the chaperone activity of the cytosolic heat inducible T. brucei Hsp70 and constitutive TbHsp70.4 proteins. The compounds were assessed for cytotoxicity on both the bloodstream form of T. b. brucei parasites and a mammalian cell line. The compounds were then investigated for their modulatory effect on the aggregation suppression and ATPase activities of the TbHsp70 proteins. A structure-activity relationship for the malonganenone-class of alkaloids is proposed based upon these results.
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Opoku F, Govender PP, Pooe OJ, Simelane MB. Evaluating Iso-Mukaadial Acetate and Ursolic Acid Acetate as Plasmodium falciparum Hypoxanthine-Guanine-Xanthine Phosphoribosyltransferase Inhibitors. Biomolecules 2019; 9:E861. [PMID: 31835879 PMCID: PMC6995562 DOI: 10.3390/biom9120861] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/06/2019] [Accepted: 12/10/2019] [Indexed: 12/21/2022] Open
Abstract
To date, Plasmodium falciparum is one of the most lethal strains of the malaria parasite. P. falciparum lacks the required enzymes to create its own purines via the de novo pathway, thereby making Plasmodium falciparum hypoxanthine-guanine-xanthine phosphoribosyltransferase (PfHGXPT) a crucial enzyme in the malaria life cycle. Recently, studies have described iso-mukaadial acetate and ursolic acid acetate as promising antimalarials. However, the mode of action is still unknown, thus, the current study sought to investigate the selective inhibitory and binding actions of iso-mukaadial acetate and ursolic acid acetate against recombinant PfHGXPT using in-silico and experimental approaches. Recombinant PfHGXPT protein was expressed using E. coli BL21 cells and homogeneously purified by affinity chromatography. Experimentally, iso-mukaadial acetate and ursolic acid acetate, respectively, demonstrated direct inhibitory activity towards PfHGXPT in a dose-dependent manner. The binding affinity of iso-mukaadial acetate and ursolic acid acetate on the PfHGXPT dissociation constant (KD), where it was found that 0.0833 µM and 2.8396 µM, respectively, are indicative of strong binding. The mode of action for the observed antimalarial activity was further established by a molecular docking study. The molecular docking and dynamics simulations show specific interactions and high affinity within the binding pocket of Plasmodium falciparum and human hypoxanthine-guanine phosphoribosyl transferases. The predicted in silico absorption, distribution, metabolism and excretion/toxicity (ADME/T) properties predicted that the iso-mukaadial acetate ligand may follow the criteria for orally active drugs. The theoretical calculation derived from ADME, molecular docking and dynamics provide in-depth information into the structural basis, specific bonding and non-bonding interactions governing the inhibition of malarial. Taken together, these findings provide a basis for the recommendation of iso-mukaadial acetate and ursolic acid acetate as high-affinity ligands and drug candidates against PfHGXPT.
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Affiliation(s)
- Francis Opoku
- Department of Chemical Sciences, University of Johannesburg, P.O. Box 17011, Doornfontein Campus, Johannesburg 2028, South Africa;
| | - Penny P. Govender
- Department of Chemical Sciences, University of Johannesburg, P.O. Box 17011, Doornfontein Campus, Johannesburg 2028, South Africa;
| | - Ofentse J. Pooe
- Discipline of Biochemistry, School of Life Science, University of KwaZulu-Natal, Westville 4000, South Africa;
| | - Mthokozisi B.C. Simelane
- Department of Biochemistry, Faculty of Science, University of Johannesburg, Johannesburg 2006, South Africa
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23
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Zininga T, Shonhai A. Small Molecule Inhibitors Targeting the Heat Shock Protein System of Human Obligate Protozoan Parasites. Int J Mol Sci 2019; 20:E5930. [PMID: 31775392 PMCID: PMC6929125 DOI: 10.3390/ijms20235930] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/29/2019] [Accepted: 11/13/2019] [Indexed: 12/13/2022] Open
Abstract
Obligate protozoan parasites of the kinetoplastids and apicomplexa infect human cells to complete their life cycles. Some of the members of these groups of parasites develop in at least two systems, the human host and the insect vector. Survival under the varied physiological conditions associated with the human host and in the arthropod vectors requires the parasites to modulate their metabolic complement in order to meet the prevailing conditions. One of the key features of these parasites essential for their survival and host infectivity is timely expression of various proteins. Even more importantly is the need to keep their proteome functional by maintaining its functional capabilities in the wake of physiological changes and host immune responses. For this reason, molecular chaperones (also called heat shock proteins)-whose role is to facilitate proteostasis-play an important role in the survival of these parasites. Heat shock protein 90 (Hsp90) and Hsp70 are prominent molecular chaperones that are generally induced in response to physiological stress. Both Hsp90 and Hsp70 members are functionally regulated by nucleotides. In addition, Hsp70 and Hsp90 cooperate to facilitate folding of some key proteins implicated in cellular development. In addition, Hsp90 and Hsp70 individually interact with other accessory proteins (co-chaperones) that regulate their functions. The dependency of these proteins on nucleotide for their chaperone function presents an Achille's heel, as inhibitors that mimic ATP are amongst potential therapeutic agents targeting their function in obligate intracellular human parasites. Most of the promising small molecule inhibitors of parasitic heat shock proteins are either antibiotics or anticancer agents, whose repurposing against parasitic infections holds prospects. Both cancer cells and obligate human parasites depend upon a robust protein quality control system to ensure their survival, and hence, both employ a competent heat shock machinery to this end. Furthermore, some inhibitors that target chaperone and co-chaperone networks also offer promising prospects as antiparasitic agents. The current review highlights the progress made so far in design and application of small molecule inhibitors against obligate intracellular human parasites of the kinetoplastida and apicomplexan kingdoms.
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Affiliation(s)
| | - Addmore Shonhai
- Department of Biochemistry, School of Mathematical and Natural Sciences, University of Venda, Thohoyandou 0950, South Africa;
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Bentley SJ, Boshoff A. Trypanosoma brucei J-Protein 2 Functionally Co-Operates with the Cytosolic Hsp70 and Hsp70.4 Proteins. Int J Mol Sci 2019; 20:E5843. [PMID: 31766407 PMCID: PMC6928772 DOI: 10.3390/ijms20235843] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 11/05/2019] [Accepted: 11/07/2019] [Indexed: 12/31/2022] Open
Abstract
The etiological agent of African trypanosomiasis, Trypanosoma brucei (Tb), has been identified to possess an expanded and diverse group of heat shock proteins, which have been implicated in cytoprotection, differentiation, and subsequently progression and transmission of the disease. Heat shock protein 70 (Hsp70) is a highly conserved and ubiquitous molecular chaperone that is important in maintaining protein homeostasis in the cell. Its function is regulated by a wide range of co-chaperones, and inhibition of these functions and interactions with co-chaperones are emerging as potential therapeutic targets for numerous diseases. This study sought to biochemically characterize the cytosolic TbHsp70 and TbHsp70.4 proteins and to investigate if they functionally co-operate with the Type I J-protein, Tbj2. Expression of TbHsp70 was shown to be heat inducible, while TbHsp70.4 was constitutively expressed. The basal ATPase activities of TbHsp70.4 and TbHsp70 were stimulated by Tbj2. It was further determined that Tbj2 functionally co-operated with TbHsp70 and TbHsp70.4 as the J-protein was shown to stimulate the ability of both proteins to mediate the refolding of chemically denatured β-galactosidase. This study provides further insight into this important class of proteins, which may contribute to the development of new therapeutic strategies to combat African Trypanosomiasis.
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Affiliation(s)
| | - Aileen Boshoff
- Biotechnology Innovation Centre, Rhodes University, Grahamstown 6140, South Africa;
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25
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The Link That Binds: The Linker of Hsp70 as a Helm of the Protein's Function. Biomolecules 2019; 9:biom9100543. [PMID: 31569820 PMCID: PMC6843406 DOI: 10.3390/biom9100543] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 09/13/2019] [Accepted: 09/21/2019] [Indexed: 12/26/2022] Open
Abstract
The heat shock 70 (Hsp70) family of molecular chaperones plays a central role in maintaining cellular proteostasis. Structurally, Hsp70s are composed of an N-terminal nucleotide binding domain (NBD) which exhibits ATPase activity, and a C-terminal substrate binding domain (SBD). The binding of ATP at the NBD and its subsequent hydrolysis influences the substrate binding affinity of the SBD through allostery. Similarly, peptide binding at the C-terminal SBD stimulates ATP hydrolysis by the N-terminal NBD. Interdomain communication between the NBD and SBD is facilitated by a conserved linker segment. Hsp70s form two main subgroups. Canonical Hsp70 members generally suppress protein aggregation and are also capable of refolding misfolded proteins. Hsp110 members are characterized by an extended lid segment and their function tends to be largely restricted to suppression of protein aggregation. In addition, the latter serve as nucleotide exchange factors (NEFs) of canonical Hsp70s. The linker of the Hsp110 family is less conserved compared to that of the canonical Hsp70 group. In addition, the linker plays a crucial role in defining the functional features of these two groups of Hsp70. Generally, the linker of Hsp70 is quite small and varies in size from seven to thirteen residues. Due to its small size, any sequence variation that Hsp70 exhibits in this motif has a major and unique influence on the function of the protein. Based on sequence data, we observed that canonical Hsp70s possess a linker that is distinct from similar segments present in Hsp110 proteins. In addition, Hsp110 linker motifs from various genera are distinct suggesting that their unique features regulate the flexibility with which the NBD and SBD of these proteins communicate via allostery. The Hsp70 linker modulates various structure-function features of Hsp70 such as its global conformation, affinity for peptide substrate and interaction with co-chaperones. The current review discusses how the unique features of the Hsp70 linker accounts for the functional specialization of this group of molecular chaperones.
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26
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Halder V, Suliman MNS, Kaschani F, Kaiser M. Plant chemical genetics reveals colistin sulphate as a SA and NPR1-independent PR1 inducer functioning via a p38-like kinase pathway. Sci Rep 2019; 9:11196. [PMID: 31371749 PMCID: PMC6671972 DOI: 10.1038/s41598-019-47526-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 07/18/2019] [Indexed: 01/07/2023] Open
Abstract
In plants, low-dose of exogenous bacterial cyclic lipopeptides (CLPs) trigger transient membrane changes leading to activation of early and late defence responses. Here, a forward chemical genetics approach identifies colistin sulphate (CS) CLP as a novel plant defence inducer. CS uniquely triggers activation of the PATHOGENESIS-RELATED 1 (PR1) gene and resistance against Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) in Arabidopsis thaliana (Arabidopsis) independently of the PR1 classical inducer, salicylic acid (SA) and the key SA-signalling protein, NON-EXPRESSOR OF PR1 (NPR1). Low bioactive concentration of CS does not trigger activation of early defence markers such as reactive oxygen species (ROS) and mitogen activated protein kinase (MAPK). However, it strongly suppresses primary root length elongation. Structure activity relationship (SAR) assays and mode-of-action (MoA) studies show the acyl chain and activation of a ∼46 kDa p38-like kinase pathway to be crucial for CS' bioactivity. Selective pharmacological inhibition of the active p38-like kinase pathway by SB203580 reverses CS' effects on PR1 activation and root length suppression. Our results with CS as a chemical probe highlight the existence of a novel SA- and NPR1-independent branch of PR1 activation functioning via a membrane-sensitive p38-like kinase pathway.
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Affiliation(s)
- Vivek Halder
- Chemical Biology Laboratory, Max Planck Institute of Plant Breeding Research, Carl-von-Linnè-Weg 10, 50829, Köln, Germany. .,Chemical Biology, Centre of Medical Biotechnology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 2, 45141, Essen, Germany. .,Rijk Zwaan, De Lier, 2678 ZG, The Netherlands.
| | - Mohamed N S Suliman
- Chemical Biology Laboratory, Max Planck Institute of Plant Breeding Research, Carl-von-Linnè-Weg 10, 50829, Köln, Germany.,Desert Research Centre, 11753 El matareya, Cairo, Egypt
| | - Farnusch Kaschani
- Chemical Biology, Centre of Medical Biotechnology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 2, 45141, Essen, Germany
| | - Markus Kaiser
- Chemical Biology, Centre of Medical Biotechnology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 2, 45141, Essen, Germany.
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27
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Daniyan MO, Przyborski JM, Shonhai A. Partners in Mischief: Functional Networks of Heat Shock Proteins of Plasmodium falciparum and Their Influence on Parasite Virulence. Biomolecules 2019; 9:E295. [PMID: 31340488 PMCID: PMC6681276 DOI: 10.3390/biom9070295] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 06/28/2019] [Accepted: 06/28/2019] [Indexed: 02/06/2023] Open
Abstract
The survival of the human malaria parasite Plasmodium falciparum under the physiologically distinct environments associated with their development in the cold-blooded invertebrate mosquito vectors and the warm-blooded vertebrate human host requires a genome that caters to adaptability. To this end, a robust stress response system coupled to an efficient protein quality control system are essential features of the parasite. Heat shock proteins constitute the main molecular chaperone system of the cell, accounting for approximately two percent of the malaria genome. Some heat shock proteins of parasites constitute a large part (5%) of the 'exportome' (parasite proteins that are exported to the infected host erythrocyte) that modify the host cell, promoting its cyto-adherence. In light of their importance in protein folding and refolding, and thus the survival of the parasite, heat shock proteins of P. falciparum have been a major subject of study. Emerging evidence points to their role not only being cyto-protection of the parasite, as they are also implicated in regulating parasite virulence. In undertaking their roles, heat shock proteins operate in networks that involve not only partners of parasite origin, but also potentially functionally associate with human proteins to facilitate parasite survival and pathogenicity. This review seeks to highlight these interplays and their roles in parasite pathogenicity. We further discuss the prospects of targeting the parasite heat shock protein network towards the developments of alternative antimalarial chemotherapies.
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Affiliation(s)
- Michael O Daniyan
- Department of Pharmacology, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Osun State 220005, Nigeria.
| | - Jude M Przyborski
- Center of Infectious Diseases, Parasitology, University of Heidelberg Medical School, INF324, 69120 Heidelberg, Germany
| | - Addmore Shonhai
- Department of Biochemistry, School of Mathematical & Natural Sciences, University of Venda, P. Bag X5050, Thohoyandou 0950, South Africa.
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Batista FA, Dores-Silva PR, Borges JC. Molecular Chaperones Involved in Protein Recovery from Aggregates are Present in Protozoa Causative of Malaria and Leishmaniasis. CURR PROTEOMICS 2018. [DOI: 10.2174/1570164615666180626123823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Molecular chaperones have several critical functions in protein metabolism. Among them,
some are involved in processes that culminate in the extraction of entangled polypeptides from protein
aggregates, releasing unfolded structures prone to be refolded or directed to degradation. This action
avoids the effect of toxic aggregates on cells and tissues. Molecular chaperones belonging to the
Hsp100 family are widely distributed from unicellular and sessile organisms up to fungi and plants,
exerting key functions related to the reduction of the effects caused by different forms of stress. The
Hsp100 proteins belong to the AAA+ (ATPases Associated with diverse cellular Activities) family and
form multichaperone systems with Hsp70 and small Hsp chaperones families. However, Hsp100 are
absent in metazoan, where protein disaggregation action is performed by a system involving the Hsp70
family, including Hsp110 and J-protein co-chaperones. Here, the structural and functional aspects of
these protein disaggregation systems will be reviewed and discussed in the perspective of the Hsp100
system absent in the metazoan kingdom. This feature focuses on Hsp100 as a hot spot for drug discovery
against human infectious diseases such as leishmaniasis and malaria, as Hsp100 is critical for microorganisms.
The current data available for Hsp100 in Leishmania spp. and Plasmodium spp. are also
reviewed.
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Affiliation(s)
- Fernanda A.H. Batista
- Instituto de Quimica de Sao Carlos, Universidade de Sao Paulo, Sao Carlos, SP, Brazil
| | - Paulo R. Dores-Silva
- Instituto de Quimica de Sao Carlos, Universidade de Sao Paulo, Sao Carlos, SP, Brazil
| | - Júlio C. Borges
- Instituto de Quimica de Sao Carlos, Universidade de Sao Paulo, Sao Carlos, SP, Brazil
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Heat Shock Proteins as Immunomodulants. Molecules 2018; 23:molecules23112846. [PMID: 30388847 PMCID: PMC6278532 DOI: 10.3390/molecules23112846] [Citation(s) in RCA: 212] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 10/30/2018] [Accepted: 10/30/2018] [Indexed: 12/24/2022] Open
Abstract
Heat shock proteins (Hsps) are conserved molecules whose main role is to facilitate folding of other proteins. Most Hsps are generally stress-inducible as they play a particularly important cytoprotective role in cells exposed to stressful conditions. Initially, Hsps were generally thought to occur intracellulary. However, recent work has shown that some Hsps are secreted to the cell exterior particularly in response to stress. For this reason, they are generally regarded as danger signaling biomarkers. In this way, they prompt the immune system to react to prevailing adverse cellular conditions. For example, their enhanced secretion by cancer cells facilitate targeting of these cells by natural killer cells. Notably, Hsps are implicated in both pro-inflammatory and anti-inflammatory responses. Their effects on immune cells depends on a number of aspects such as concentration of the respective Hsp species. In addition, various Hsp species exert unique effects on immune cells. Because of their conservation, Hsps are implicated in auto-immune diseases. Here we discuss the various metabolic pathways in which various Hsps manifest immune modulation. In addition, we discuss possible experimental variations that may account for contradictory reports on the immunomodulatory function of some Hsps.
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(-)-Epigallocatechin-3-Gallate Inhibits the Chaperone Activity of Plasmodium falciparum Hsp70 Chaperones and Abrogates Their Association with Functional Partners. Molecules 2017; 22:molecules22122139. [PMID: 29206141 PMCID: PMC6149709 DOI: 10.3390/molecules22122139] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 11/30/2017] [Accepted: 12/01/2017] [Indexed: 11/17/2022] Open
Abstract
Heat shock proteins (Hsps), amongst them, Hsp70 and Hsp90 families, serve mainly as facilitators of protein folding (molecular chaperones) of the cell. The Hsp70 family of proteins represents one of the most important molecular chaperones in the cell. Plasmodium falciparum, the main agent of malaria, expresses six Hsp70 isoforms. Two (PfHsp70-1 and PfHsp70-z) of these localize to the parasite cytosol. PHsp70-1 is known to occur in a functional complex with another chaperone, PfHsp90 via a co-chaperone, P. falciparum Hsp70-Hsp90 organising protein (PfHop). (-)-Epigallocatechin-3-gallate (EGCG) is a green tea constituent that is thought to possess antiplasmodial activity. However, the mechanism by which EGCG exhibits antiplasmodial activity is not fully understood. A previous study proposed that EGCG binds to the N-terminal ATPase domain of Hsp70. In the current study, we overexpressed and purified recombinant forms of two P. falciparum cytosol localized Hsp70s (PfHsp70-1 and PfHsp70-z), and PfHop, a co-chaperone of PfHsp70-1. Using the surface plasmon resonance approach, we demonstrated that EGCG directly binds to the two Hsp70s. We further observed that binding of EGCG to the two proteins resulted in secondary and tertiary conformational changes. In addition, EGCG inhibited the ATPase and chaperone function of the two proteins. Furthermore, EGCG abrogated association of the two Hsp70s with their functional partners. Using parasites cultured in vitro at the blood stages, we observed that 2.9 µM EGCG suppressed 50% P. falciparum parasite growth (IC50). Our findings demonstrate that EGCG directly binds to PfHsp70-1 and PfHsp70-z to inhibit both the ATPase and chaperone functions of the proteins. Our study constitutes the first direct evidence suggesting that the antiplasmodial activity of EGCG is at least in part accounted for by its inhibition of Hsp70 function.
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Zininga T, Anokwuru CP, Sigidi MT, Tshisikhawe MP, Ramaite IID, Traoré AN, Hoppe H, Shonhai A, Potgieter N. Extracts Obtained from Pterocarpus angolensis DC and Ziziphus mucronata Exhibit Antiplasmodial Activity and Inhibit Heat Shock Protein 70 (Hsp70) Function. Molecules 2017; 22:molecules22081224. [PMID: 28788073 PMCID: PMC6152082 DOI: 10.3390/molecules22081224] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 07/17/2017] [Accepted: 07/18/2017] [Indexed: 11/23/2022] Open
Abstract
Malaria parasites are increasingly becoming resistant to currently used antimalarial therapies, therefore there is an urgent need to expand the arsenal of alternative antimalarial drugs. In addition, it is also important to identify novel antimalarial drug targets. In the current study, extracts of two plants, Pterocarpus angolensis and Ziziphus mucronata were obtained and their antimalarial functions were investigated. Furthermore, we explored the capability of the extracts to inhibit Plasmodium falciparum heat shock protein 70 (Hsp70) function. Heat shock protein 70 (Hsp70) are molecular chaperones whose function is to facilitate protein folding. Plasmodium falciparum the main agent of malaria, expresses two cytosol-localized Hsp70s: PfHsp70-1 and PfHsp70-z. The PfHsp70-z has been reported to be essential for parasite survival, while inhibition of PfHsp70-1 function leads to parasite death. Hence both PfHsp70-1 and PfHsp70-z are potential antimalarial drug targets. Extracts of P. angolensis and Z. mucronata inhibited the basal ATPase and chaperone functions of the two parasite Hsp70s. Furthermore, fractions of P. angolensis and Z. mucronata inhibited P. falciparum 3D7 parasite growth in vitro. The extracts obtained in the current study exhibited antiplasmodial activity as they killed P. falciparum parasites maintained in vitro. In addition, the findings further suggest that some of the compounds in P. angolensis and Z. mucronata may target parasite Hsp70 function.
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Affiliation(s)
- Tawanda Zininga
- Biochemistry Department, School of Mathematical and Natural Sciences, University of Venda, Private Bag X5050, 0950 Thohoyandou, South Africa.
| | - Chinedu P Anokwuru
- Chemistry Department, School of Mathematical and Natural Sciences, University of Venda, Private Bag X5050, 0950 Thohoyandou, South Africa.
| | - Muendi T Sigidi
- Microbiology Department, School of Mathematical and Natural Sciences, University of Venda, Private Bag X5050, 0950 Thohoyandou, South Africa.
| | - Milingoni P Tshisikhawe
- Botany Department, School of Mathematical and Natural Sciences, University of Venda, Private Bag X5050, 0950 Thohoyandou, South Africa.
| | - Isaiah I D Ramaite
- Chemistry Department, School of Mathematical and Natural Sciences, University of Venda, Private Bag X5050, 0950 Thohoyandou, South Africa.
| | - Afsatou N Traoré
- Microbiology Department, School of Mathematical and Natural Sciences, University of Venda, Private Bag X5050, 0950 Thohoyandou, South Africa.
| | - Heinrich Hoppe
- Department of Biochemistry and Microbiology, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa.
| | - Addmore Shonhai
- Biochemistry Department, School of Mathematical and Natural Sciences, University of Venda, Private Bag X5050, 0950 Thohoyandou, South Africa.
| | - Natasha Potgieter
- Microbiology Department, School of Mathematical and Natural Sciences, University of Venda, Private Bag X5050, 0950 Thohoyandou, South Africa.
- School of Mathematical and Natural Sciences, University of Venda, Private Bag X5050, 0950 Thohoyandou, South Africa.
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Extracts Obtained from Pterocarpus angolensis DC and Ziziphus mucronata Exhibit Antiplasmodial Activity and Inhibit Heat Shock Protein 70 (Hsp70) Function. Molecules 2017. [DOI: 10.3390/molecules22071224] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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