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Krantz BA. Anthrax Toxin: Model System for Studying Protein Translocation. J Mol Biol 2024; 436:168521. [PMID: 38458604 DOI: 10.1016/j.jmb.2024.168521] [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: 11/17/2023] [Revised: 02/08/2024] [Accepted: 03/04/2024] [Indexed: 03/10/2024]
Abstract
Dedicated translocase channels are nanomachines that often, but not always, unfold and translocate proteins through narrow pores across the membrane. Generally, these molecular machines utilize external sources of free energy to drive these reactions, since folded proteins are thermodynamically stable, and once unfolded they contain immense diffusive configurational entropy. To catalyze unfolding and translocate the unfolded state at appreciable timescales, translocase channels often utilize analogous peptide-clamp active sites. Here we describe how anthrax toxin has been used as a biophysical model system to study protein translocation. The tripartite bacterial toxin is composed of an oligomeric translocase channel, protective antigen (PA), and two enzymes, edema factor (EF) and lethal factor (LF), which are translocated by PA into mammalian host cells. Unfolding and translocation are powered by the endosomal proton gradient and are catalyzed by three peptide-clamp sites in the PA channel: the α clamp, the ϕ clamp, and the charge clamp. These clamp sites interact nonspecifically with the chemically complex translocating chain, serve to minimize unfolded state configurational entropy, and work cooperatively to promote translocation. Two models of proton gradient driven translocation have been proposed: (i) an extended-chain Brownian ratchet mechanism and (ii) a proton-driven helix-compression mechanism. These models are not mutually exclusive; instead the extended-chain Brownian ratchet likely operates on β-sheet sequences and the helix-compression mechanism likely operates on α-helical sequences. Finally, we compare and contrast anthrax toxin with other related and unrelated translocase channels.
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Affiliation(s)
- Bryan A Krantz
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, 650 W. Baltimore Street, Baltimore, MD 21201, USA.
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Popoff MR. Overview of Bacterial Protein Toxins from Pathogenic Bacteria: Mode of Action and Insights into Evolution. Toxins (Basel) 2024; 16:182. [PMID: 38668607 PMCID: PMC11054074 DOI: 10.3390/toxins16040182] [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: 02/16/2024] [Revised: 03/29/2024] [Accepted: 03/30/2024] [Indexed: 04/29/2024] Open
Abstract
Bacterial protein toxins are secreted by certain bacteria and are responsible for mild to severe diseases in humans and animals. They are among the most potent molecules known, which are active at very low concentrations. Bacterial protein toxins exhibit a wide diversity based on size, structure, and mode of action. Upon recognition of a cell surface receptor (protein, glycoprotein, and glycolipid), they are active either at the cell surface (signal transduction, membrane damage by pore formation, or hydrolysis of membrane compound(s)) or intracellularly. Various bacterial protein toxins have the ability to enter cells, most often using an endocytosis mechanism, and to deliver the effector domain into the cytosol, where it interacts with an intracellular target(s). According to the nature of the intracellular target(s) and type of modification, various cellular effects are induced (cell death, homeostasis modification, cytoskeleton alteration, blockade of exocytosis, etc.). The various modes of action of bacterial protein toxins are illustrated with representative examples. Insights in toxin evolution are discussed.
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Affiliation(s)
- Michel R Popoff
- Unité des Toxines Bactériennes, Institut Pasteur, Université Paris Cité, CNRS UMR 2001 INSERM U1306, F-75015 Paris, France
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Tessier E, Cheutin L, Garnier A, Vigne C, Tournier JN, Rougeaux C. Early Circulating Edema Factor in Inhalational Anthrax Infection: Does It Matter? Microorganisms 2024; 12:308. [PMID: 38399712 PMCID: PMC10891819 DOI: 10.3390/microorganisms12020308] [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: 11/29/2023] [Revised: 01/22/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
Anthrax toxins are critical virulence factors of Bacillus anthracis and Bacillus cereus strains that cause anthrax-like disease, composed of a common binding factor, the protective antigen (PA), and two enzymatic proteins, lethal factor (LF) and edema factor (EF). While PA is required for endocytosis and activity of EF and LF, several studies showed that these enzymatic factors disseminate within the body in the absence of PA after intranasal infection. In an effort to understand the impact of EF in the absence of PA, we used a fluorescent EF chimera to facilitate the study of endocytosis in different cell lines. Unexpectedly, EF was found inside cells in the absence of PA and showed a pole-dependent endocytosis. However, looking at enzymatic activity, PA was still required for EF to induce an increase in intracellular cAMP levels. Interestingly, the sequential delivery of EF and then PA rescued the rise in cAMP levels, indicating that PA and EF may functionally associate during intracellular trafficking, as well as it did at the cell surface. Our data shed new light on EF trafficking and the potential location of PA and EF association for optimal cytosolic delivery.
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Affiliation(s)
- Emilie Tessier
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
| | - Laurence Cheutin
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
| | - Annabelle Garnier
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
| | - Clarisse Vigne
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
| | - Jean-Nicolas Tournier
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
- Institut Pasteur, 75015 Paris, France
| | - Clémence Rougeaux
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
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Goossens PL. Bacillus anthracis, "la maladie du charbon", Toxins, and Institut Pasteur. Toxins (Basel) 2024; 16:66. [PMID: 38393144 PMCID: PMC10891547 DOI: 10.3390/toxins16020066] [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: 11/08/2023] [Revised: 12/25/2023] [Accepted: 12/30/2023] [Indexed: 02/25/2024] Open
Abstract
Institut Pasteur and Bacillus anthracis have enjoyed a relationship lasting almost 120 years, starting from its foundation and the pioneering work of Louis Pasteur in the nascent fields of microbiology and vaccination, and blooming after 1986 following the molecular biology/genetic revolution. This contribution will give a historical overview of these two research eras, taking advantage of the archives conserved at Institut Pasteur. The first era mainly focused on the production, characterisation, surveillance and improvement of veterinary anthrax vaccines; the concepts and technologies with which to reach a deep understanding of this research field were not yet available. The second period saw a new era of B. anthracis research at Institut Pasteur, with the anthrax laboratory developing a multi-disciplinary approach, ranging from structural analysis, biochemistry, genetic expression, and regulation to bacterial-host cell interactions, in vivo pathogenicity, and therapy development; this led to the comprehensive unravelling of many facets of this toxi-infection. B. anthracis may exemplify some general points on how science is performed in a given society at a given time and how a scientific research domain evolves. A striking illustration can be seen in the additive layers of regulations that were implemented from the beginning of the 21st century and their impact on B. anthracis research. B. anthracis and anthrax are complex systems that raise many valuable questions regarding basic research. One may hope that B. anthracis research will be re-initiated under favourable circumstances later at Institut Pasteur.
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Yin L, Thaker H. Cancer Drug Delivery Systems Using Bacterial Toxin Translocation Mechanisms. Bioengineering (Basel) 2023; 10:813. [PMID: 37508840 PMCID: PMC10376142 DOI: 10.3390/bioengineering10070813] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 06/16/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023] Open
Abstract
Recent advances in targeted cancer therapy hold great promise for both research and clinical applications and push the boundaries in finding new treatments for various currently incurable cancers. However, these therapies require specific cell-targeting mechanisms for the efficient delivery of drug cargo across the cell membrane to reach intracellular targets and avoid diffusion to unwanted tissues. Traditional drug delivery systems suffer from a limited ability to travel across the barriers posed by cell membranes and, therefore, there is a need for high doses, which are associated with adverse reactions and safety concerns. Bacterial toxins have evolved naturally to specifically target cell subtypes via their receptor binding module, penetrating the cell membrane efficiently through the membrane translocation process and then successfully delivering the toxic cargo into the host cytosol. They have, thus, been harnessed for the delivery of various drugs. In this review, we focus on bacterial toxin translocation mechanisms and recent progress in the targeted delivery systems of cancer therapy drugs that have been inspired by the receptor binding and membrane translocation processes of the anthrax toxin protective antigen, diphtheria toxin, and Pseudomonas exotoxin A. We also discuss the challenges and limitations of these studies that should be addressed before bacterial toxin-based drug delivery systems can become a viable new generation of drug delivery approaches in clinical translation.
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Affiliation(s)
- Linxiang Yin
- Department of Urology, Boston Children's Hospital, Boston, MA 02115, USA
- Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Hatim Thaker
- Department of Urology, Boston Children's Hospital, Boston, MA 02115, USA
- Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
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Shinde S, Miryala SK, Anbarasu A, Ramaiah S. Systems biology approach to understand the interplay between Bacillus anthracis and human host genes that leads to CVDs. Microb Pathog 2023; 176:106019. [PMID: 36736801 DOI: 10.1016/j.micpath.2023.106019] [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: 10/31/2022] [Revised: 01/28/2023] [Accepted: 01/31/2023] [Indexed: 02/04/2023]
Abstract
Humans infected with invasive Bacillus anthracis (B. anthracis) have a very poor prognosis and are at high risk for developing cardiovascular diseases (CVDs) and shock. Several bacterial elements probably have significant pathogenic roles in this pathogenic process of anthrax. In our current work, we have analysed the molecular level interactions between B. anthracis and human genes to understand the interplay during anthrax that leads to the CVDs. Our results have shown dense interactions between the functional partners in both host and the B. anthracis Gene interaction network (GIN). The functional enrichment analysis indicated that the clusters in the host GIN had genes related to hypoxia and autophagy in response to the lethal toxin; and genes related to adherens junction and actin cytoskeleton in response to edema toxin play a significant role in multiple stages of the disease. The B. anthracis genes BA_0530, guaA, polA, rpoB, ribD, secDF, metS, dinG and human genes ACTB, EGFR, EP300, CTNNB1, ESR1 have shown more than 50 direct interactions with the functional partners and hence they can be considered as hub genes in the network and they are observed to have important roles in CVDs. The outcome of our study will help to understand the molecular pathogenesis of CVDs in anthrax. The hub genes reported in the study can be considered potential drug targets and they can be exploited for new drug discovery.
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Affiliation(s)
- Shabduli Shinde
- School of Medical Science and Technology, Indian Institute of Technology, Kharagpur, Kharagpur, 721302, West Bengal, India
| | - Sravan Kumar Miryala
- Medical and Biological Computing Laboratory, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, 632014, Tamil Nadu, India
| | - Anand Anbarasu
- Medical and Biological Computing Laboratory, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, 632014, Tamil Nadu, India
| | - Sudha Ramaiah
- Medical and Biological Computing Laboratory, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, 632014, Tamil Nadu, India.
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Boyer AE, Gallegos-Candela M, Lins RC, Solano MI, Woolfitt AR, Lee JS, Sanford DC, Knostman KAB, Quinn CP, Hoffmaster AR, Pirkle JL, Barr JR. Comprehensive characterization of toxins during progression of inhalation anthrax in a non-human primate model. PLoS Pathog 2022; 18:e1010735. [PMID: 36534695 PMCID: PMC9810172 DOI: 10.1371/journal.ppat.1010735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 01/03/2023] [Accepted: 11/28/2022] [Indexed: 12/23/2022] Open
Abstract
Inhalation anthrax has three clinical stages: early-prodromal, intermediate-progressive, and late-fulminant. We report the comprehensive characterization of anthrax toxins, including total protective antigen (PA), total lethal factor (LF), total edema factor (EF), and their toxin complexes, lethal toxin and edema toxin in plasma, during the course of inhalation anthrax in 23 cynomolgus macaques. The toxin kinetics were predominantly triphasic with an early rise (phase-1), a plateau/decline (phase-2), and a final rapid rise (phase-3). Eleven animals had shorter survival times, mean±standard deviation of 58.7±7.6 hours (fast progression), 11 animals had longer survival times, 113±34.4 hours (slow progression), and one animal survived. Median (lower-upper quartile) LF levels at the end-of-phase-1 were significantly higher in animals with fast progression [138 (54.9-326) ng/mL], than in those with slow progression [23.8 (15.6-26.3) ng/mL] (p = 0.0002), and the survivor (11.1 ng/mL). The differences were also observed for other toxins and bacteremia. Animals with slow progression had an extended phase-2 plateau, with low variability of LF levels across all time points and animals. Characterization of phase-2 toxin levels defined upper thresholds; critical levels for exiting phase-2 and entering the critical phase-3, 342 ng/mL (PA), 35.8 ng/mL (LF), and 1.10 ng/mL (EF). The thresholds were exceeded earlier in animals with fast progression (38.5±7.4 hours) and later in animals with slow progression (78.7±15.2 hours). Once the threshold was passed, toxin levels rose rapidly in both groups to the terminal stage. The time from threshold to terminal was rapid and similar; 20.8±7.4 hours for fast and 19.9±7.5 hours for slow progression. The three toxemic phases were aligned with the three clinical stages of anthrax for fast and slow progression which showed that anthrax progression is toxin- rather than time-dependent. This first comprehensive evaluation of anthrax toxins provides new insights into disease progression.
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Affiliation(s)
- Anne E. Boyer
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- * E-mail:
| | | | - Renato C. Lins
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- Battelle Atlanta Analytical Services, Atlanta, Georgia, United States of America
| | - Maria I. Solano
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Adrian R. Woolfitt
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - John S. Lee
- Biomedical Advanced Research and Development Authority, Washington, DC, United States of America
| | - Daniel C. Sanford
- Battelle Biomedical Research Center, West Jefferson, Ohio, United States of America
| | | | - Conrad P. Quinn
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Alex R. Hoffmaster
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - James L. Pirkle
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - John R. Barr
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
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Scott H, Huang W, Andra K, Mamillapalli S, Gonti S, Day A, Zhang K, Mehzabeen N, Battaile KP, Raju A, Lovell S, Bann JG, Taylor DJ. Structure of the anthrax protective antigen D425A dominant negative mutant reveals a stalled intermediate state of pore maturation. J Mol Biol 2022; 434:167548. [PMID: 35304125 DOI: 10.1016/j.jmb.2022.167548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 03/01/2022] [Accepted: 03/10/2022] [Indexed: 10/18/2022]
Abstract
The tripartite protein complex produced by anthrax bacteria (Bacillus anthracis) is a member of the AB family of β-barrel pore-forming toxins. The protective antigen (PA) component forms an oligomeric prepore that assembles on the host cell surface and serves as a scaffold for binding of lethal and edema factors. Following endocytosis, the acidic environment of the late endosome triggers a pH-induced conformational rearrangement to promote maturation of the PA prepore to a functional, membrane spanning pore that facilitates delivery of lethal and edema factors to the cytosol of the infected host. Here, we show that the dominant-negative D425A mutant of PA stalls anthrax pore maturation in an intermediate state at acidic pH. Our 2.7 Å cryo-EM structure of the intermediate state reveals structural rearrangements that involve constriction of the oligomeric pore combined with an intramolecular dissociation of the pore-forming module. In addition to defining the early stages of anthrax pore maturation, the structure identifies asymmetric conformational changes in the oligomeric pore that are influenced by the precise configuration of adjacent protomers.
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Affiliation(s)
- Harry Scott
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Wei Huang
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Kiran Andra
- Department of Chemistry, Wichita State University, Wichita, KS 67260, USA
| | | | - Srinivas Gonti
- Department of Chemistry, Wichita State University, Wichita, KS 67260, USA
| | - Alexander Day
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Kaiming Zhang
- Stanford Linear Accelerator Center and the Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Nurjahan Mehzabeen
- Protein Structure Laboratory, University of Kansas, Lawrence, KS 66047, USA
| | - Kevin P Battaile
- IMCA-CAT, APS, Argonne National Laboratory, 9700 South Cass Avenue, Building 435A, Argonne, IL 60439, USA
| | - Anjali Raju
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Scott Lovell
- Protein Structure Laboratory, University of Kansas, Lawrence, KS 66047, USA
| | - James G Bann
- Department of Chemistry, Wichita State University, Wichita, KS 67260, USA.
| | - Derek J Taylor
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA; Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106, USA.
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9
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Minato T, Teramoto T, Adachi N, Hung NK, Yamada K, Kawasaki M, Akutsu M, Moriya T, Senda T, Ogo S, Kakuta Y, Yoon KS. Non-conventional octameric structure of C-phycocyanin. Commun Biol 2021; 4:1238. [PMID: 34716405 PMCID: PMC8556327 DOI: 10.1038/s42003-021-02767-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 10/05/2021] [Indexed: 11/29/2022] Open
Abstract
C-phycocyanin (CPC), a blue pigment protein, is an indispensable component of giant phycobilisomes, which are light-harvesting antenna complexes in cyanobacteria that transfer energy efficiently to photosystems I and II. X-ray crystallographic and electron microscopy (EM) analyses have revealed the structure of CPC to be a closed toroidal hexamer by assembling two trimers. In this study, the structural characterization of non-conventional octameric CPC is reported for the first time. Analyses of the crystal and cryogenic EM structures of the native CPC from filamentous thermophilic cyanobacterium Thermoleptolyngbya sp. O–77 unexpectedly illustrated the coexistence of conventional hexamer and novel octamer. In addition, an unusual dimeric state, observed via analytical ultracentrifugation, was postulated to be a key intermediate structure in the assemble of the previously unobserved octamer. These observations provide new insights into the assembly processes of CPCs and the mechanism of energy transfer in the light-harvesting complexes. Takuo Minato and colleagues determine the crystal and cryo-EM structures of the native C-phycocyanin (CPC) from the thermophilic cyanobacterium, Thermoleptolyngbya sp. O77, which was found to adopt both a conventional hexameric structure and a novel octameric assembly. These findings provide new insights into the assembly of CPCs and their mechanism of energy transfer.
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Affiliation(s)
- Takuo Minato
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.,International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.,Department of Applied Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8527, Japan
| | - Takamasa Teramoto
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Naruhiko Adachi
- Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Nguyen Khac Hung
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.,International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Kaho Yamada
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.,International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Masato Kawasaki
- Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan.,Department of Materials Structure Science, School of High Energy Accelerator Science, The Graduate University of Advanced Studies (Soken-dai), 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Masato Akutsu
- Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Toshio Moriya
- Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Toshiya Senda
- Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan.,Department of Materials Structure Science, School of High Energy Accelerator Science, The Graduate University of Advanced Studies (Soken-dai), 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Seiji Ogo
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.,International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.,Center for Small Molecule Energy, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Yoshimitsu Kakuta
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan. .,Laboratory of Structural Biology, Graduate School of System Life Sciences, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.
| | - Ki-Seok Yoon
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan. .,International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan. .,Center for Small Molecule Energy, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.
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10
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Banihashemi SR, Rahbarizadeh F, Zavaran Hosseini A, Ahmadvand D, Khoshtinat Nikkhoi S. Liposome-based nanocarriers loaded with anthrax lethal factor and armed with anti-CD19 VHH for effectively inhibiting MAPK pathway in B cells. Int Immunopharmacol 2021; 100:107927. [PMID: 34500284 DOI: 10.1016/j.intimp.2021.107927] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 01/26/2023]
Abstract
OBJECTIVE One of the vital signaling pathways in cancer development and metastasis is mitogen-activated protein kinases (MAPKs). Bacillus anthracis Lethal Toxin (LT) is a potent MAPK signaling inhibitor. This toxin is comprised of two distinct domains, Lethal Factor (LF), MAPK inhibitor, and Protective Antigen (PA). To enter various cell lines, LF must be associated with the protective antigen (PA), which facilitates LF delivery. In the current study, to block MAPK signaling, LF was loaded into anti-CD19 immunoliposomes nanoparticle to deliver the cargo to Raji B cells. METHODS The liposome nanoparticle was prepared using classical lipid film formation, then conjugated to anti-CD19 VHH. The binding efficiency was measured through flow cytometry. The targeted cytotoxicity of LF immunoliposome was confirmed by BrdU lymphoproliferation assay. This was followed by Real-Time PCR to assess the effect of formulation on pro-apoptotic genes. The inhibitory effect of LF on MAPK signaling was confirmed by western blot. RESULTS Liposome nano-formulation was optimized to reach the maximum LF encapsulation and targeted delivery. Next, phosphorylation of MAPK pathway mediators like MEK1/2, P38 and JNK were inhibited following the treatment of Raji cells with LF-immunoliposome. The treatment also upregulated caspase genes, clearly illustrating cell death induced by LF through pyroptosis and caspase-dependent apoptosis. CONCLUSIONS In conclusion, anti-CD19 VHH immunoliposome was loaded with LF, a potent MAPK inhibitor targeting B cells, which curbs proliferation and ushers B cells toward apoptosis. Thus, immunoliposome presents as a versatile nanoparticle for delivery of LF to block aberrant MAPK activation. To use LF as a therapy, it would be necessary to materialize LF without PA. In the current study, PA was substituted with anti-CD19 immunoliposome to make it targeted to CD19+ while keeping the normal cells intact.
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Affiliation(s)
- S Reza Banihashemi
- Department of Medical Immunology, Faculty of Medical Sciences, Tarbiat Modarres University, Tehran, Iran; Department of Immunology, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization, Karaj, Iran
| | - Fatemeh Rahbarizadeh
- Department of Medical Biotechnology, Faculty of Medical Sciences, Tarbiat Modarres University, Tehran, Iran.
| | - Ahmad Zavaran Hosseini
- Department of Medical Immunology, Faculty of Medical Sciences, Tarbiat Modarres University, Tehran, Iran
| | - Davoud Ahmadvand
- School of Allied Medical Sciences, Iran University of Medical Sciences, Tehran, Iran
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11
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Hoelzgen F, Zalk R, Alcalay R, Cohen-Schwartz S, Garau G, Shahar A, Mazor O, Frank GA. Neutralization of the anthrax toxin by antibody-mediated stapling of its membrane-penetrating loop. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2021; 77:1197-1205. [PMID: 34473089 DOI: 10.1107/s2059798321007816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/30/2021] [Indexed: 12/15/2022]
Abstract
Anthrax infection is associated with severe illness and high mortality. Protective antigen (PA) is the central component of the anthrax toxin, which is one of two major virulence factors of Bacillus anthracis, the causative agent of anthrax disease. Upon endocytosis, PA opens a pore in the membranes of endosomes, through which the cytotoxic enzymes of the toxin are extruded. The PA pore is formed by a cooperative conformational change in which the membrane-penetrating loops of PA associate, forming a hydrophobic rim that pierces the membrane. Due to its crucial role in anthrax progression, PA is an important target for monoclonal antibody-based therapy. cAb29 is a highly effective neutralizing antibody against PA. Here, the cryo-EM structure of PA in complex with the Fab portion of cAb29 was determined. It was found that cAb29 neutralizes the toxin by clamping the membrane-penetrating loop of PA to the static surface-exposed loop of the D3 domain of the same subunit, thereby preventing pore formation. These results provide the structural basis for the antibody-based neutralization of PA and bring into focus the membrane-penetrating loop of PA as a target for the development of better anti-anthrax vaccines.
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Affiliation(s)
- F Hoelzgen
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 8410501, Israel
| | - R Zalk
- Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer Sheva 8410501, Israel
| | - R Alcalay
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - S Cohen-Schwartz
- The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva 8410501, Israel
| | - G Garau
- Biostructures Lab, IIT@NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, 56124 Pisa, Italy
| | - A Shahar
- Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer Sheva 8410501, Israel
| | - O Mazor
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - G A Frank
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 8410501, Israel
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12
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Becker L, Singh Badwal J, Brandl F, Verdurmen WPR, Plückthun A. Thermodynamic Stability Is a Strong Predictor for the Delivery of DARPins to the Cytosol via Anthrax Toxin. Pharmaceutics 2021; 13:pharmaceutics13081285. [PMID: 34452246 PMCID: PMC8401532 DOI: 10.3390/pharmaceutics13081285] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 08/05/2021] [Indexed: 11/16/2022] Open
Abstract
Anthrax toxin has evolved to translocate its toxic cargo proteins to the cytosol of cells carrying its cognate receptor. Cargo molecules need to unfold to penetrate the narrow pore formed by its membrane-spanning subunit, protective antigen (PA). Various alternative cargo molecules have previously been tested, with some showing only limited translocation efficiency, and it may be assumed that these were too stable to be unfolded before passing through the anthrax pore. In this study, we systematically and quantitatively analyzed the correlation between the translocation of various designed ankyrin repeat proteins (DARPins) and their different sizes and thermodynamic stabilities. To measure cytosolic uptake, we used biotinylation of the cargo by cytosolic BirA, and we measured cargo equilibrium stability via denaturant-induced unfolding, monitored by circular dichroism (CD). Most of the tested DARPin cargoes, including target-binding ones, were translocated to the cytosol. Those DARPins, which remained trapped in the endosome, were confirmed by CD to show a high equilibrium stability. We could pinpoint a stability threshold up to which cargo DARPins still get translocated to the cytosol. These experiments have outlined the requirements for translocatable binding proteins, relevant stability measurements to assess translocatable candidates, and guidelines to further engineer this property if needed.
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Affiliation(s)
- Lukas Becker
- Department of Biochemistry, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland; (L.B.); (J.S.B.); (F.B.)
| | - Jasleen Singh Badwal
- Department of Biochemistry, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland; (L.B.); (J.S.B.); (F.B.)
| | - Fabian Brandl
- Department of Biochemistry, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland; (L.B.); (J.S.B.); (F.B.)
| | - Wouter P. R. Verdurmen
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University Medical Center, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands;
| | - Andreas Plückthun
- Department of Biochemistry, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland; (L.B.); (J.S.B.); (F.B.)
- Correspondence:
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13
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Martchenko Shilman M, Bartolo G, Alameh S, Peterson JW, Lawrence WS, Peel JE, Sivasubramani SK, Beasley DWC, Cote CK, Demons ST, Halasahoris SA, Miller LL, Klimko CP, Shoe JL, Fetterer DP, McComb R, Ho CLC, Bradley KA, Hartmann S, Cheng LW, Chugunova M, Kao CY, Tran JK, Derbedrossian A, Zilbermintz L, Amali-Adekwu E, Levitin A, West J. In Vivo Activity of Repurposed Amodiaquine as a Host-Targeting Therapy for the Treatment of Anthrax. ACS Infect Dis 2021; 7:2176-2191. [PMID: 34218660 PMCID: PMC8369491 DOI: 10.1021/acsinfecdis.1c00190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Anthrax is caused by Bacillus anthracis and can result in nearly 100% mortality due in part to anthrax toxin. Antimalarial amodiaquine (AQ) acts as a host-oriented inhibitor of anthrax toxin endocytosis. Here, we determined the pharmacokinetics and safety of AQ in mice, rabbits, and humans as well as the efficacy in the fly, mouse, and rabbit models of anthrax infection. In the therapeutic-intervention studies, AQ nearly doubled the survival of mice infected subcutaneously with a B. anthracis dose lethal to 60% of the animals (LD60). In rabbits challenged with 200 LD50 of aerosolized B. anthracis, AQ as a monotherapy delayed death, doubled the survival rate of infected animals that received a suboptimal amount of antibacterial levofloxacin, and reduced bacteremia and toxemia in tissues. Surprisingly, the anthrax efficacy of AQ relies on an additional host macrophage-directed antibacterial mechanism, which was validated in the toxin-independent Drosophila model of Bacillus infection. Lastly, a systematic literature review of the safety and pharmacokinetics of AQ in humans from over 2 000 published articles revealed that AQ is likely safe when taken as prescribed, and its pharmacokinetics predicts anthrax efficacy in humans. Our results support the future examination of AQ as adjunctive therapy for the prophylactic anthrax treatment.
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Affiliation(s)
- Mikhail Martchenko Shilman
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute (KGI), 535 Watson Drive, Claremont, California 91711, United States
- Shield Pharma LLC, 1420 North Claremont Boulevard, Suite 102A, Claremont, California 91711, United States
| | - Gloria Bartolo
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute (KGI), 535 Watson Drive, Claremont, California 91711, United States
| | - Saleem Alameh
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute (KGI), 535 Watson Drive, Claremont, California 91711, United States
| | - Johnny W. Peterson
- Department of Microbiology and Immunology, University of Texas Medical Branch (UTMB), 301 University Boulevard, Galveston, Texas 77555, United States
| | - William S. Lawrence
- Department of Microbiology and Immunology, University of Texas Medical Branch (UTMB), 301 University Boulevard, Galveston, Texas 77555, United States
| | - Jennifer E. Peel
- Department of Microbiology and Immunology, University of Texas Medical Branch (UTMB), 301 University Boulevard, Galveston, Texas 77555, United States
| | - Satheesh K. Sivasubramani
- Directorate of Environmental Health Effects Laboratory, Naval Medical Research Unit, Wright-Patterson Air Force Base, 2728 Q Street, Building 837, Wright-Patterson AFB, Ohio 45433, United States
| | - David W. C. Beasley
- Department of Microbiology and Immunology, University of Texas Medical Branch (UTMB), 301 University Boulevard, Galveston, Texas 77555, United States
| | - Christopher K. Cote
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, Maryland 21702, United States
| | - Samandra T. Demons
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, Maryland 21702, United States
| | - Stephanie A. Halasahoris
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, Maryland 21702, United States
| | - Lynda L. Miller
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, Maryland 21702, United States
| | - Christopher P. Klimko
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, Maryland 21702, United States
| | - Jennifer L. Shoe
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, Maryland 21702, United States
| | - David P. Fetterer
- Biostatistics Division, U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, Maryland 21702, United States
| | - Ryan McComb
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute (KGI), 535 Watson Drive, Claremont, California 91711, United States
| | - Chi-Lee C. Ho
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), 609 Charles E. Young Drive East, Los Angeles, California 90095, United States
| | - Kenneth A. Bradley
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), 609 Charles E. Young Drive East, Los Angeles, California 90095, United States
| | - Stella Hartmann
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute (KGI), 535 Watson Drive, Claremont, California 91711, United States
| | - Luisa W. Cheng
- Foodborne Toxin Detection and Prevention Research Unit, Western Regional Research Center, United States Department of Agriculture (USDA), 800 Buchanan Street, Albany, California 94710, United States
| | - Marina Chugunova
- Institute of Mathematical Sciences, Claremont Graduate University (CGU), 150 East 10th Street, Claremont, California 91711, United States
| | - Chiu-Yen Kao
- Department of Mathematical Sciences, Claremont McKenna College (CMC), 888 North Columbia Avenue, Claremont, California 91711, United States
| | - Jennifer K. Tran
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute (KGI), 535 Watson Drive, Claremont, California 91711, United States
| | - Aram Derbedrossian
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute (KGI), 535 Watson Drive, Claremont, California 91711, United States
| | - Leeor Zilbermintz
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute (KGI), 535 Watson Drive, Claremont, California 91711, United States
| | - Emiene Amali-Adekwu
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute (KGI), 535 Watson Drive, Claremont, California 91711, United States
| | - Anastasia Levitin
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute (KGI), 535 Watson Drive, Claremont, California 91711, United States
| | - Joel West
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute (KGI), 535 Watson Drive, Claremont, California 91711, United States
- Shield Pharma LLC, 1420 North Claremont Boulevard, Suite 102A, Claremont, California 91711, United States
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14
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Liu W, Nestorovich EM. Anthrax toxin channel: What we know based on over 30 years of research. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183715. [PMID: 34332985 DOI: 10.1016/j.bbamem.2021.183715] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 07/21/2021] [Accepted: 07/24/2021] [Indexed: 10/20/2022]
Abstract
Protective antigen channel is the central component of the deadly anthrax exotoxin responsible for binding and delivery of the toxin's enzymatic lethal and edema factor components into the cytosol. The channel, which is more than three times longer than the lipid bilayer membrane thickness and has a 6-Å limiting diameter, is believed to provide a sophisticated unfoldase and translocase machinery for the foreign protein transport into the host cell cytosol. The tripartite toxin can be reengineered, one component at a time or collectively, to adapt it for the targeted cancer therapeutic treatments. In this review, we focus on the biophysical studies of the protective antigen channel-forming activity, small ion transport properties, enzymatic factor translocation, and blockage comparing it with the related clostridial binary toxin channels. We address issues linked to the anthrax toxin channel structural dynamics and lipid dependence, which are yet to become generally recognized as parts of the toxin translocation machinery.
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Affiliation(s)
- Wenxing Liu
- Department of Biology, The Catholic University of America, 620 Michigan Ave, Washington, DC 20064, USA
| | - Ekaterina M Nestorovich
- Department of Biology, The Catholic University of America, 620 Michigan Ave, Washington, DC 20064, USA.
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15
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Machen AJ, Fisher MT, Freudenthal BD. Anthrax toxin translocation complex reveals insight into the lethal factor unfolding and refolding mechanism. Sci Rep 2021; 11:13038. [PMID: 34158520 PMCID: PMC8219829 DOI: 10.1038/s41598-021-91596-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 05/27/2021] [Indexed: 11/09/2022] Open
Abstract
Translocation is essential to the anthrax toxin mechanism. Protective antigen (PA), the binding component of this AB toxin, forms an oligomeric pore that translocates lethal factor (LF) or edema factor, the active components of the toxin, into the cell. Structural details of the translocation process have remained elusive despite their biological importance. To overcome the technical challenges of studying translocation intermediates, we developed a method to immobilize, transition, and stabilize anthrax toxin to mimic important physiological steps in the intoxication process. Here, we report a cryoEM snapshot of PApore translocating the N-terminal domain of LF (LFN). The resulting 3.3 Å structure of the complex shows density of partially unfolded LFN near the canonical PApore binding site. Interestingly, we also observe density consistent with an α helix emerging from the 100 Å β barrel channel suggesting LF secondary structural elements begin to refold in the pore channel. We conclude the anthrax toxin β barrel aids in efficient folding of its enzymatic payload prior to channel exit. Our hypothesized refolding mechanism has broader implications for pore length of other protein translocating toxins.
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Affiliation(s)
- Alexandra J Machen
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Mark T Fisher
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA.
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA.
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16
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Yamini G, Kanchi S, Kalu N, Momben Abolfath S, Leppla SH, Ayappa KG, Maiti PK, Nestorovich EM. Hydrophobic Gating and 1/ f Noise of the Anthrax Toxin Channel. J Phys Chem B 2021; 125:5466-5478. [PMID: 34015215 DOI: 10.1021/acs.jpcb.0c10490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
"Pink" or 1/f noise is a natural phenomenon omnipresent in physics, economics, astrophysics, biology, and even music and languages. In electrophysiology, the stochastic activity of a number of biological ion channels and artificial nanopores could be characterized by current noise with a 1/f power spectral density. In the anthrax toxin channel (PA63), it appears as fast voltage-independent current interruptions between conducting and nonconducting states. This behavior hampers potential development of PA63 as an ion-channel biosensor. On the bright side, the PA63 flickering represents a mesmerizing phenomenon to investigate. Notably, similar 1/f fluctuations are observed in the channel-forming components of clostridial binary C2 and iota toxins, which share functional and structural similarities with the anthrax toxin channel. Similar to PA63, they are evolved to translocate the enzymatic components of the toxins into the cytosol. Here, using high-resolution single-channel lipid bilayer experiments and all-atom molecular dynamic simulations, we suggest that the 1/f noise in PA63 occurs as a result of "hydrophobic gating" at the ϕ-clamp region, the phenomenon earlier observed in several water-filled channels "fastened" inside by the hydrophobic belts. The ϕ-clamp is a narrow "hydrophobic ring" in the PA63 lumen formed by seven or eight phenylalanine residues at position 427, conserved in the C2 and iota toxin channels, which catalyzes protein translocation. Notably, the 1/f noise remains undetected in the F427A PA63 mutant. This finding can elucidate the functional purpose of 1/f noise and its possible role in the transport of the enzymatic components of binary toxins.
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Affiliation(s)
- Goli Yamini
- Department of Biology, The Catholic University of America, 620 Michigan Avenue, Washington D.C., 20064, United States
| | - Subbarao Kanchi
- Department of Chemical Engineering, Indian Institute of Science, Bengaluru 560012, India.,Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bengaluru 560012, India
| | - Nnanya Kalu
- Department of Biology, The Catholic University of America, 620 Michigan Avenue, Washington D.C., 20064, United States
| | - Sanaz Momben Abolfath
- Department of Biology, The Catholic University of America, 620 Michigan Avenue, Washington D.C., 20064, United States
| | - Stephen H Leppla
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - K Ganapathy Ayappa
- Department of Chemical Engineering, Indian Institute of Science, Bengaluru 560012, India
| | - Prabal K Maiti
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bengaluru 560012, India
| | - Ekaterina M Nestorovich
- Department of Biology, The Catholic University of America, 620 Michigan Avenue, Washington D.C., 20064, United States
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17
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Lu Z, Truex NL, Melo MB, Cheng Y, Li N, Irvine DJ, Pentelute BL. IgG-Engineered Protective Antigen for Cytosolic Delivery of Proteins into Cancer Cells. ACS CENTRAL SCIENCE 2021; 7:365-378. [PMID: 33655074 PMCID: PMC7908032 DOI: 10.1021/acscentsci.0c01670] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Indexed: 05/05/2023]
Abstract
Therapeutic immunotoxins composed of antibodies and bacterial toxins provide potent activity against malignant cells, but joining them with a defined covalent bond while maintaining the desired function is challenging. Here, we develop novel immunotoxins by dovetailing full-length immunoglobulin G (IgG) antibodies and nontoxic anthrax proteins, in which the C terminus of the IgG heavy chain is connected to the side chain of anthrax toxin protective antigen. This strategy enabled efficient conjugation of protective antigen variants to trastuzumab (Tmab) and cetuximab (Cmab) antibodies. The conjugates effectively perform intracellular delivery of edema factor and N terminus of lethal factor (LFN) fused with diphtheria toxin and Ras/Rap1-specific endopeptidase. Each conjugate shows high specificity for cells expressing human epidermal growth factor receptor 2 (HER2) and epidermal growth factor receptor (EGFR), respectively, and potent activity across six Tmab- and Cmab-resistant cell lines. The conjugates also exhibit increased pharmacokinetics and pronounced in vivo safety, which shows promise for further therapeutic development.
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Affiliation(s)
- Zeyu Lu
- Department
of Chemistry, Massachusetts Institute of
Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Nicholas L. Truex
- Department
of Chemistry, Massachusetts Institute of
Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Mariane B. Melo
- The
Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, Massachusetts 02142, United States
- Ragon
Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Yiran Cheng
- Department
of Chemistry, Massachusetts Institute of
Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Na Li
- The
Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, Massachusetts 02142, United States
| | - Darrell J. Irvine
- The
Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, Massachusetts 02142, United States
- Ragon
Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
- Department
of Materials Science and Engineering, Massachusetts
Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
- Department
of Biological Engineering, Massachusetts
Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
- Howard Hughes
Medical Institute, 4000
Jones Bridge Road, Chevy Chase, Maryland 20815, United
States
| | - Bradley L. Pentelute
- Department
of Chemistry, Massachusetts Institute of
Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
- The
Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, Massachusetts 02142, United States
- Center
for Environmental Health Sciences, Massachusetts
Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
- Broad
Institute of MIT and Harvard, 415 Main Street, Cambridge, Massachusetts 02142, United States
- E-mail:
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18
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Yamada T, Tsuge H. Preparation of Clostridium perfringens binary iota-toxin pore complex for structural analysis using cryo-EM. Methods Enzymol 2021; 649:125-148. [PMID: 33712185 DOI: 10.1016/bs.mie.2021.01.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Iota toxin, a type of A-B toxin produced by Clostridium perfringens, comprises an enzymatic component (Ia) and a membrane-binding component (Ib). The translocation of Ia to the target cell via the pore formed by Ib allows it to function as an ADP-ribosyltransferase that inhibits actin polymerization in the host cell. The structure of Ia-bound Ib-pore has been determined using cryo-electron microscopy (cryo-EM), thereby elucidating the mechanism of the initial Ia translocation; however, open questions regarding Ia translocation still exist. In this chapter, we describe a new method of preparing Ia-bound Ib-pore complex samples for structural analysis at high resolution using cryo-EM. This method is different from previously reported methods for other A-B toxins. Consequently, it produces Ib-pore with two different states with short and long membrane-spanning β-barrel stem. We expect that this method will be useful in functional and structural studies of iota toxin and other binary toxins.
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Affiliation(s)
- Tomohito Yamada
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan.
| | - Hideaki Tsuge
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan; Institute for Protein Dynamics, Kyoto Sangyo University, Kyoto, Japan; Center for Molecular Research in Infectious Diseases, Kyoto Sangyo University, Kyoto, Japan.
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19
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The Buzz about ADP-Ribosylation Toxins from Paenibacillus larvae, the Causative Agent of American Foulbrood in Honey Bees. Toxins (Basel) 2021; 13:toxins13020151. [PMID: 33669183 PMCID: PMC7919650 DOI: 10.3390/toxins13020151] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/02/2021] [Accepted: 02/11/2021] [Indexed: 11/26/2022] Open
Abstract
The Gram-positive, spore-forming bacterium Paenibacillus larvae is the etiological agent of American Foulbrood, a highly contagious and often fatal honey bee brood disease. The species P. larvae comprises five so-called ERIC-genotypes which differ in virulence and pathogenesis strategies. In the past two decades, the identification and characterization of several P. larvae virulence factors have led to considerable progress in understanding the molecular basis of pathogen-host-interactions during P. larvae infections. Among these virulence factors are three ADP-ribosylating AB-toxins, Plx1, Plx2, and C3larvin. Plx1 is a phage-born toxin highly homologous to the pierisin-like AB-toxins expressed by the whites-and-yellows family Pieridae (Lepidoptera, Insecta) and to scabin expressed by the plant pathogen Streptomyces scabiei. These toxins ADP-ribosylate DNA and thus induce apoptosis. While the presumed cellular target of Plx1 still awaits final experimental proof, the classification of the A subunits of the binary AB-toxins Plx2 and C3larvin as typical C3-like toxins, which ADP-ribosylate Rho-proteins, has been confirmed experimentally. Normally, C3-exoenzymes do not occur together with a B subunit partner, but as single domain toxins. Interestingly, the B subunits of the two P. larvae C3-like toxins are homologous to the B-subunits of C2-like toxins with striking structural similarity to the PA-63 protomer of Bacillus anthracis.
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20
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Gonti S, Westler WM, Miyagi M, Bann JG. Site-Specific Labeling and 19F NMR Provide Direct Evidence for Dynamic Behavior of the Anthrax Toxin Pore ϕ-Clamp Structure. Biochemistry 2021; 60:643-647. [PMID: 33428379 DOI: 10.1021/acs.biochem.0c00833] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The anthrax toxin protective antigen (PA), the membrane binding and pore-forming component of the anthrax toxin, was studied using 19F NMR. We site-specifically labeled PA with p-fluorophenylalanine (pF-Phe) at Phe427, a critically important residue that comprises the ϕ-clamp that is required for translocation of edema factor (EF) and lethal factor (LF) into the host cell cytosol. We utilized 19F NMR to follow low-pH-induced structural changes in the prepore, alone and bound to the N-terminal PA binding domain of LF, LFN. Our studies indicate that pF-Phe427 is dynamic in the prepore state and then becomes more dynamic in the transition to the pore. An increase in dynamic behavior at the ϕ-clamp may provide the necessary room for movement needed in translocating EF and LF into the cell cytosol.
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Affiliation(s)
- Srinivas Gonti
- Department of Chemistry and Biochemistry, Wichita State University, Wichita, Kansas 67260, United States
| | - William M Westler
- National Magnetic Resonance Facility at Madison and Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706-1544, United States
| | - Masaru Miyagi
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - James G Bann
- Department of Chemistry and Biochemistry, Wichita State University, Wichita, Kansas 67260, United States
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21
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Harnessing the Membrane Translocation Properties of AB Toxins for Therapeutic Applications. Toxins (Basel) 2021; 13:toxins13010036. [PMID: 33418946 PMCID: PMC7825107 DOI: 10.3390/toxins13010036] [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: 11/04/2020] [Revised: 12/28/2020] [Accepted: 01/01/2021] [Indexed: 12/31/2022] Open
Abstract
Over the last few decades, proteins and peptides have become increasingly more common as FDA-approved drugs, despite their inefficient delivery due to their inability to cross the plasma membrane. In this context, bacterial two-component systems, termed AB toxins, use various protein-based membrane translocation mechanisms to deliver toxins into cells, and these mechanisms could provide new insights into the development of bio-based drug delivery systems. These toxins have great potential as therapies both because of their intrinsic properties as well as the modular characteristics of both subunits, which make them highly amenable to conjugation with various drug classes. This review focuses on the therapeutical approaches involving the internalization mechanisms of three representative AB toxins: botulinum toxin type A, anthrax toxin, and cholera toxin. We showcase several specific examples of the use of these toxins to develop new therapeutic strategies for numerous diseases and explain what makes these toxins promising tools in the development of drugs and drug delivery systems.
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Abstract
Anthrax toxin is a major virulence factor of Bacillus anthracis, a Gram-positive bacterium which can form highly stable spores that are the causative agents of the disease, anthrax. While chiefly a disease of livestock, spores can be "weaponized" as a bio-terrorist agent, and can be deadly if not recognized and treated early with antibiotics. The intracellular pathways affected by the enzymes are broadly understood and are not discussed here. This chapter focuses on what is known about the assembly of secreted toxins on the host cell surface and how the toxin is delivered into the cytosol. The central component is the "Protective Antigen", which self-oligomerizes and forms complexes with its pay-load, either Lethal Factor or Edema Factor. It binds a host receptor, CMG2, or a close relative, triggering receptor-mediated endocytosis, and forms a remarkably elegant yet powerful machine that delivers toxic enzymes into the cytosol, powered only by the pH gradient across the membrane. We now have atomic structures of most of the starting, intermediate and final assemblies in the infectious process. Together with a major body of biophysical, mutational and biochemical work, these studies reveal a remarkable story of both how toxin assembly is choreographed in time and space.
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Ni X, Jiang J. Cryo-EM Uncovers Atomic Details for Loading Cell-Killing Enzymes to the Anthrax Toxin Pretranslocation Complex. Structure 2020; 28:871-873. [PMID: 32755568 DOI: 10.1016/j.str.2020.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this issue of Structure, Zhou et al. report the structures of full-length lethal and edema factors, the cytotoxic components of the deadly anthrax toxin, in complex with the toxin's cell binding and delivery module, the protective antigen prechannel, providing an atomic description for the toxin recruitment prior to translocation.
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Affiliation(s)
- Xiaodan Ni
- Laboratory of Membrane Proteins and Structural Biology, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jiansen Jiang
- Laboratory of Membrane Proteins and Structural Biology, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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Lo SY, Goulet DL, Fraaz U, Siemann S. Effect of pH and denaturants on the fold and metal status of anthrax lethal factor. Arch Biochem Biophys 2020; 692:108547. [PMID: 32828796 DOI: 10.1016/j.abb.2020.108547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 08/02/2020] [Accepted: 08/17/2020] [Indexed: 01/26/2023]
Abstract
Anthrax lethal factor (LF) is a critical component of the anthrax toxin, and functions intracellularly as a zinc-dependent endopeptidase targeting proteins involved in maintaining critical host signaling pathways. To reach the cytoplasm, LF requires to be unfolded and guided through the narrow protective antigen pore in a pH-dependent process. The current study sought to address the question as to whether LF is capable of retaining its metal ion when exposed to a low-pH environment (similar to that found in late endosomes) and an unfolding stress (induced by urea). Using a combination of tryptophan fluorescence spectroscopy and chelation studies, we show that a decrease in the pH value (from 7.0 to 5.0) leads to a pronounced shift in the onset of structural alterations in LF to lower urea concentrations. More importantly, the enzyme was found to retain its Zn2+ ion beyond the unfolding transitions monitored by Trp fluorescence, a finding indicative of tight metal binding to LF in a non-native state. In addition, an analysis of red-edge excitation shift (REES) spectra suggests the protein to maintain residual structure (a feature necessary for metal binding) even at very high denaturant concentrations. Furthermore, studies using the chromophoric chelator 4-(2-pyridylazo)resorcinol (PAR) revealed LF's Zn2+ ion to become accessible to complexation at urea concentrations in between those required to cause structural changes and metal dissociation. This phenomenon likely originates from the conversion of a PAR-inaccessible (closed) to a PAR-accessible (open) state of LF at intermediate denaturant concentrations.
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Affiliation(s)
- Suet Y Lo
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, P3E 2C6, Canada
| | - Danica L Goulet
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, P3E 2C6, Canada
| | - Usama Fraaz
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, P3E 2C6, Canada
| | - Stefan Siemann
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, P3E 2C6, Canada.
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Alameh S, Bartolo G, O’Brien S, Henderson EA, Gonzalez LO, Hartmann S, Klimko CP, Shoe JL, Cote CK, Grill LK, Levitin A, Martchenko Shilman M. Anthrax toxin component, Protective Antigen, protects insects from bacterial infections. PLoS Pathog 2020; 16:e1008836. [PMID: 32866212 PMCID: PMC7458312 DOI: 10.1371/journal.ppat.1008836] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 07/24/2020] [Indexed: 01/23/2023] Open
Abstract
Anthrax is a major zoonotic disease of wildlife, and in places like West Africa, it can be caused by Bacillus anthracis in arid nonsylvatic savannahs, and by B. cereus biovar anthracis (Bcbva) in sylvatic rainforests. Bcbva-caused anthrax has been implicated in as much as 38% of mortality in rainforest ecosystems, where insects can enhance the transmission of anthrax-causing bacteria. While anthrax is well-characterized in mammals, its transmission by insects points to an unidentified anthrax-resistance mechanism in its vectors. In mammals, a secreted anthrax toxin component, 83 kDa Protective Antigen (PA83), binds to cell-surface receptors and is cleaved by furin into an evolutionary-conserved PA20 and a pore-forming PA63 subunits. We show that PA20 increases the resistance of Drosophila flies and Culex mosquitoes to bacterial challenges, without directly affecting the bacterial growth. We further show that the PA83 loop known to be cleaved by furin to release PA20 from PA63 is, in part, responsible for the PA20-mediated protection. We found that PA20 binds directly to the Toll activating peptidoglycan-recognition protein-SA (PGRP-SA) and that the Toll/NF-κB pathway is necessary for the PA20-mediated protection of infected flies. This effect of PA20 on innate immunity may also exist in mammals: we show that PA20 binds to human PGRP-SA ortholog. Moreover, the constitutive activity of Imd/NF-κB pathway in MAPKK Dsor1 mutant flies is sufficient to confer the protection from bacterial infections in a manner that is independent of PA20 treatment. Lastly, Clostridium septicum alpha toxin protects flies from anthrax-causing bacteria, showing that other pathogens may help insects resist anthrax. The mechanism of anthrax resistance in insects has direct implications on insect-mediated anthrax transmission for wildlife management, and with potential for applications, such as reducing the sensitivity of pollinating insects to bacterial pathogens.
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Affiliation(s)
- Saleem Alameh
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Gloria Bartolo
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Summer O’Brien
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Elizabeth A. Henderson
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Leandra O. Gonzalez
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Stella Hartmann
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Christopher P. Klimko
- Bacteriology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, United States of America
| | - Jennifer L. Shoe
- Bacteriology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, United States of America
| | - Christopher K. Cote
- Bacteriology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, United States of America
| | - Laurence K. Grill
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Anastasia Levitin
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
- * E-mail: (AL); (MMS)
| | - Mikhail Martchenko Shilman
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
- * E-mail: (AL); (MMS)
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Manish M, Verma S, Kandari D, Kulshreshtha P, Singh S, Bhatnagar R. Anthrax prevention through vaccine and post-exposure therapy. Expert Opin Biol Ther 2020; 20:1405-1425. [DOI: 10.1080/14712598.2020.1801626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Manish Manish
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Shashikala Verma
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | - Divya Kandari
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Parul Kulshreshtha
- Department of Zoology, Shivaji College, University of Delhi, Delhi, India
| | - Samer Singh
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
- Department of Microbial Biotechnology, Panjab University, Chandigarh, India
| | - Rakesh Bhatnagar
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
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Cryo-EM structure of the fully-loaded asymmetric anthrax lethal toxin in its heptameric pre-pore state. PLoS Pathog 2020; 16:e1008530. [PMID: 32810181 PMCID: PMC7462287 DOI: 10.1371/journal.ppat.1008530] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 09/01/2020] [Accepted: 06/27/2020] [Indexed: 12/20/2022] Open
Abstract
Anthrax toxin is the major virulence factor secreted by Bacillus anthracis, causing high mortality in humans and other mammals. It consists of a membrane translocase, known as protective antigen (PA), that catalyzes the unfolding of its cytotoxic substrates lethal factor (LF) and edema factor (EF), followed by translocation into the host cell. Substrate recruitment to the heptameric PA pre-pore and subsequent translocation, however, are not well understood. Here, we report three high-resolution cryo-EM structures of the fully-loaded anthrax lethal toxin in its heptameric pre-pore state, which differ in the position and conformation of LFs. The structures reveal that three LFs interact with the heptameric PA and upon binding change their conformation to form a continuous chain of head-to-tail interactions. As a result of the underlying symmetry mismatch, one LF binding site in PA remains unoccupied. Whereas one LF directly interacts with a part of PA called α-clamp, the others do not interact with this region, indicating an intermediate state between toxin assembly and translocation. Interestingly, the interaction of the N-terminal domain with the α-clamp correlates with a higher flexibility in the C-terminal domain of the protein. Based on our data, we propose a model for toxin assembly, in which the relative position of the N-terminal α-helices in the three LFs determines which factor is translocated first.
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28
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Lu Z, Paolella BR, Truex NL, Loftis AR, Liao X, Rabideau AE, Brown MS, Busanovich J, Beroukhim R, Pentelute BL. Targeting Cancer Gene Dependencies with Anthrax-Mediated Delivery of Peptide Nucleic Acids. ACS Chem Biol 2020; 15:1358-1369. [PMID: 32348107 PMCID: PMC7521945 DOI: 10.1021/acschembio.9b01027] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Antisense oligonucleotide therapies are important cancer treatments, which can suppress genes in cancer cells that are critical for cell survival. SF3B1 has recently emerged as a promising gene target that encodes a key splicing factor in the SF3B protein complex. Over 10% of cancers have lost one or more copies of the SF3B1 gene, rendering these cancers vulnerable after further suppression. SF3B1 is just one example of a CYCLOPS (Copy-number alterations Yielding Cancer Liabilities Owing to Partial losS) gene, but over 120 additional candidate CYCLOPS genes are known. Antisense oligonucleotide therapies for cancer offer the promise of effective suppression for CYCLOPS genes, but developing these treatments is difficult due to their limited permeability into cells and poor cytosolic stability. Here, we develop an effective approach to suppress CYCLOPS genes by delivering antisense peptide nucleic acids (PNAs) into the cytosol of cancer cells. We achieve efficient cytosolic PNA delivery with the two main nontoxic components of the anthrax toxin: protective antigen (PA) and the 263-residue N-terminal domain of lethal factor (LFN). Sortase-mediated ligation readily enables the conjugation of PNAs to the C terminus of the LFN protein. LFN and PA work together in concert to translocate PNAs into the cytosol of mammalian cells. Antisense SF3B1 PNAs delivered with the LFN/PA system suppress the SF3B1 gene and decrease cell viability, particularly of cancer cells with partial copy-number loss of SF3B1. Moreover, antisense SF3B1 PNAs delivered with a HER2-binding PA variant selectively target cancer cells that overexpress the HER2 cell receptor, demonstrating receptor-specific targeting of cancer cells. Taken together, our efforts illustrate how PA-mediated delivery of PNAs provides an effective and general approach for delivering antisense PNA therapeutics and for targeting gene dependencies in cancer.
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Affiliation(s)
- Zeyu Lu
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Brenton R. Paolella
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02139, USA
| | - Nicholas L. Truex
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Alexander R. Loftis
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Xiaoli Liao
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Amy E. Rabideau
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Meredith S. Brown
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02139, USA
| | - John Busanovich
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02139, USA
| | - Rameen Beroukhim
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02139, USA
| | - Bradley L. Pentelute
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
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29
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Zhou K, Liu S, Hardenbrook NJ, Cui Y, Krantz BA, Zhou ZH. Atomic Structures of Anthrax Prechannel Bound with Full-Length Lethal and Edema Factors. Structure 2020; 28:879-887.e3. [PMID: 32521227 DOI: 10.1016/j.str.2020.05.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 04/09/2020] [Accepted: 05/18/2020] [Indexed: 12/15/2022]
Abstract
Pathogenesis of anthrax disease involves two cytotoxic enzymes-edema factor (EF) and lethal factor (LF)-which are individually recruited by the protective antigen heptamer (PA7) or octamer (PA8) prechannel and subsequently translocated across channels formed on the endosomal membrane upon exposure to low pH. Here, we report the atomic structures of PA8 prechannel-bound full-length EF and LF. In this pretranslocation state, the N-terminal segment of both factors refolds into an α helix engaged in the α clamp of the prechannel. Recruitment to the PA prechannel exposes an originally buried β strand of both toxins and enables domain organization of EF. Many interactions occur on domain interfaces in both PA prechannel-bound EF and LF, leading to toxin compaction prior to translocation. Our results provide key insights into the molecular mechanisms of translocation-coupled protein unfolding and translocation.
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Affiliation(s)
- Kang Zhou
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA
| | - Shiheng Liu
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Nathan J Hardenbrook
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, MD 21201, USA
| | - Yanxiang Cui
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA
| | - Bryan A Krantz
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, MD 21201, USA.
| | - Z Hong Zhou
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA.
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30
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Larkin IN, Garimella V, Yamankurt G, Scott AW, Xing H, Mirkin CA. Dual-Readout Sandwich Immunoassay for Device-Free and Highly Sensitive Anthrax Biomarker Detection. Anal Chem 2020; 92:7845-7851. [PMID: 32437125 PMCID: PMC7418077 DOI: 10.1021/acs.analchem.0c01090] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We report a dual-readout, AuNP-based sandwich immunoassay for the device-free colorimetric and sensitive scanometric detection of disease biomarkers. An AuNP-antibody conjugate serves as a signal transduction and amplification agent by promoting the reduction and deposition of either platinum or gold onto its surface, generating corresponding colorimetric or light scattering (scanometric) signals, respectively. We apply the Pt-based colorimetric readout of this assay to the discovery of a novel monoclonal antibody (mAb) sandwich pair for the detection of an anthrax protective antigen (PA83). The identified antibody pair detects PA83 down to 1 nM in phosphate-buffered saline and 5 nM in human serum, which are physiologically relevant concentrations. Reducing gold rather than platinum onto the mAb-AuNP sandwich enables scanometric detection of subpicomolar PA83 concentrations, over 3 orders of magnitude more sensitive than the colorimetric readout.
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Affiliation(s)
- Isaac N Larkin
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60608, United States
- Department of Interdisciplinary Biological Sciences, Northwestern University, 2205 Tech Drive, Evanston, Illinois 60608, United States
| | - Viswanadham Garimella
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60608, United States
| | - Gokay Yamankurt
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60608, United States
- Department of Interdisciplinary Biological Sciences, Northwestern University, 2205 Tech Drive, Evanston, Illinois 60608, United States
| | - Alexander W Scott
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60608, United States
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60608, United States
| | - Hang Xing
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60608, United States
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60608, United States
| | - Chad A Mirkin
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60608, United States
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60608, United States
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31
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Hardenbrook NJ, Liu S, Zhou K, Ghosal K, Zhou ZH, Krantz BA. Atomic structures of anthrax toxin protective antigen channels bound to partially unfolded lethal and edema factors. Nat Commun 2020; 11:840. [PMID: 32047164 PMCID: PMC7012834 DOI: 10.1038/s41467-020-14658-6] [Citation(s) in RCA: 20] [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: 07/08/2019] [Accepted: 01/15/2020] [Indexed: 11/09/2022] Open
Abstract
Following assembly, the anthrax protective antigen (PA) forms an oligomeric translocon that unfolds and translocates either its lethal factor (LF) or edema factor (EF) into the host cell. Here, we report the cryo-EM structures of heptameric PA channels with partially unfolded LF and EF at 4.6 and 3.1-Å resolution, respectively. The first α helix and β strand of LF and EF unfold and dock into a deep amphipathic cleft, called the α clamp, which resides at the interface of two PA monomers. The α-clamp-helix interactions exhibit structural plasticity when comparing the structures of lethal and edema toxins. EF undergoes a largescale conformational rearrangement when forming the complex with the channel. A critical loop in the PA binding interface is displaced for about 4 Å, leading to the weakening of the binding interface prior to translocation. These structures provide key insights into the molecular mechanisms of translocation-coupled protein unfolding and translocation.
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Affiliation(s)
- Nathan J Hardenbrook
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, MD, 21201, USA
| | - Shiheng Liu
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA, 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA
| | - Kang Zhou
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA, 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA
| | - Koyel Ghosal
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, MD, 21201, USA
| | - Z Hong Zhou
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA, 90095, USA.
- California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA.
| | - Bryan A Krantz
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, MD, 21201, USA.
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Xu X, Godoy-Ruiz R, Adipietro KA, Peralta C, Ben-Hail D, Varney KM, Cook ME, Roth BM, Wilder PT, Cleveland T, Grishaev A, Neu HM, Michel SLJ, Yu W, Beckett D, Rustandi RR, Lancaster C, Loughney JW, Kristopeit A, Christanti S, Olson JW, MacKerell AD, Georges AD, Pozharski E, Weber DJ. Structure of the cell-binding component of the Clostridium difficile binary toxin reveals a di-heptamer macromolecular assembly. Proc Natl Acad Sci U S A 2020; 117:1049-1058. [PMID: 31896582 PMCID: PMC6969506 DOI: 10.1073/pnas.1919490117] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Targeting Clostridium difficile infection is challenging because treatment options are limited, and high recurrence rates are common. One reason for this is that hypervirulent C. difficile strains often have a binary toxin termed the C. difficile toxin, in addition to the enterotoxins TsdA and TsdB. The C. difficile toxin has an enzymatic component, termed CDTa, and a pore-forming or delivery subunit termed CDTb. CDTb was characterized here using a combination of single-particle cryoelectron microscopy, X-ray crystallography, NMR, and other biophysical methods. In the absence of CDTa, 2 di-heptamer structures for activated CDTb (1.0 MDa) were solved at atomic resolution, including a symmetric (SymCDTb; 3.14 Å) and an asymmetric form (AsymCDTb; 2.84 Å). Roles played by 2 receptor-binding domains of activated CDTb were of particular interest since the receptor-binding domain 1 lacks sequence homology to any other known toxin, and the receptor-binding domain 2 is completely absent in other well-studied heptameric toxins (i.e., anthrax). For AsymCDTb, a Ca2+ binding site was discovered in the first receptor-binding domain that is important for its stability, and the second receptor-binding domain was found to be critical for host cell toxicity and the di-heptamer fold for both forms of activated CDTb. Together, these studies represent a starting point for developing structure-based drug-design strategies to target the most severe strains of C. difficile.
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Affiliation(s)
- Xingjian Xu
- City University of New York Advanced Science Research Center, City University of New York, New York, NY 10017
- PhD Program in Biochemistry, The Graduate Center, City University of New York, New York, NY 10017
| | - Raquel Godoy-Ruiz
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Kaylin A Adipietro
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Christopher Peralta
- City University of New York Advanced Science Research Center, City University of New York, New York, NY 10017
| | - Danya Ben-Hail
- City University of New York Advanced Science Research Center, City University of New York, New York, NY 10017
| | - Kristen M Varney
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Mary E Cook
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Braden M Roth
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Paul T Wilder
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
| | | | | | - Heather M Neu
- University of Maryland School of Pharmacy, University of Maryland, Baltimore, MD 21201
| | - Sarah L J Michel
- University of Maryland School of Pharmacy, University of Maryland, Baltimore, MD 21201
| | - Wenbo Yu
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
- University of Maryland School of Pharmacy, University of Maryland, Baltimore, MD 21201
| | - Dorothy Beckett
- Department of Chemistry & Biochemistry, University of Maryland, College Park, MD 20742
| | | | | | | | | | | | | | - Alexander D MacKerell
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
- University of Maryland School of Pharmacy, University of Maryland, Baltimore, MD 21201
| | - Amedee des Georges
- City University of New York Advanced Science Research Center, City University of New York, New York, NY 10017;
- PhD Program in Biochemistry, The Graduate Center, City University of New York, New York, NY 10017
- PhD Program in Chemistry, The Graduate Center, City University of New York, New York, NY 10017
- Department of Chemistry & Biochemistry, City College of New York, New York, NY 10031
| | - Edwin Pozharski
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201;
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
| | - David J Weber
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201;
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
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Anderson DM, Sheedlo MJ, Jensen JL, Lacy DB. Structural insights into the transition of Clostridioides difficile binary toxin from prepore to pore. Nat Microbiol 2020; 5:102-107. [PMID: 31712627 PMCID: PMC6925320 DOI: 10.1038/s41564-019-0601-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 10/03/2019] [Indexed: 11/28/2022]
Abstract
Clostridioides (formerly Clostridium) difficile is a Gram-positive, spore-forming anaerobe and a leading cause of hospital-acquired infection and gastroenteritis-associated death in US hospitals1. The disease state is usually preceded by disruption of the host microbiome in response to antibiotic treatment and is characterized by mild to severe diarrhoea. C. difficile infection is dependent on the secretion of one or more AB-type toxins: toxin A (TcdA), toxin B (TcdB) and the C. difficile transferase toxin (CDT)2. Whereas TcdA and TcdB are considered the primary virulence factors, recent studies suggest that CDT increases the severity of C. difficile infection in some of the most problematic clinical strains3. To better understand how CDT functions, we used cryo-electron microscopy to define the structure of CDTb, the cell-binding component of CDT. We obtained structures of several oligomeric forms that highlight the conformational changes that enable conversion from a prepore to a β-barrel pore. The structural analysis also reveals a glycan-binding domain and residues involved in binding the host-cell receptor, lipolysis-stimulated lipoprotein receptor. Together, these results provide a framework to understand how CDT functions at the host cell interface.
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Affiliation(s)
- David M Anderson
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- The Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN, USA
| | - Michael J Sheedlo
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- The Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN, USA
| | - Jaime L Jensen
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - D Borden Lacy
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA.
- The Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN, USA.
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Omersa N, Podobnik M, Anderluh G. Inhibition of Pore-Forming Proteins. Toxins (Basel) 2019; 11:E545. [PMID: 31546810 PMCID: PMC6784129 DOI: 10.3390/toxins11090545] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/27/2019] [Accepted: 09/10/2019] [Indexed: 12/16/2022] Open
Abstract
Perforation of cellular membranes by pore-forming proteins can affect cell physiology, tissue integrity, or immune response. Since many pore-forming proteins are toxins or highly potent virulence factors, they represent an attractive target for the development of molecules that neutralize their actions with high efficacy. There has been an assortment of inhibitors developed to specifically obstruct the activity of pore-forming proteins, in addition to vaccination and antibiotics that serve as a plausible treatment for the majority of diseases caused by bacterial infections. Here we review a wide range of potential inhibitors that can specifically and effectively block the activity of pore-forming proteins, from small molecules to more specific macromolecular systems, such as synthetic nanoparticles, antibodies, antibody mimetics, polyvalent inhibitors, and dominant negative mutants. We discuss their mechanism of inhibition, as well as advantages and disadvantages.
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Affiliation(s)
- Neža Omersa
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
| | - Marjetka Podobnik
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
| | - Gregor Anderluh
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
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Exploring the Nature of Cationic Blocker Recognition by the Anthrax Toxin Channel. Biophys J 2019; 117:1751-1763. [PMID: 31587826 DOI: 10.1016/j.bpj.2019.08.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/11/2019] [Accepted: 08/05/2019] [Indexed: 01/20/2023] Open
Abstract
Obstructing conductive pathways of the channel-forming toxins with targeted blockers is a promising drug design approach. Nearly all tested positively charged ligands have been shown to reversibly block the cation-selective channel-forming protective antigen (PA63) component of the binary anthrax toxin. The cationic ligands with more hydrophobic surfaces, particularly those carrying aromatic moieties, inhibited PA63 more effectively. To understand the physical basis of PA63 selectivity for a particular ligand, detailed information is required on how the blocker structural elements (e.g., positively charged and aromatic groups) influence the molecular kinetics of the blocker/channel binding reactions. In this study, we address this problem using the high-resolution single-channel planar lipid bilayer technique. Several structurally distinct cationic blockers, namely per-6-S-(3-amino) propyl-β-cyclodextrin, per-6-S-(3-aminomethyl) benzyl-α-cyclodextrin, per-6-S-(3-aminomethyl) benzyl-β-cyclodextrin, per-6-S-(3-aminomethyl) benzyl-γ-cyclodextrin, methyltriphenylphosphonium ion, and G0 polyamidoamine dendrimer are tested for their ability to inhibit the heptameric and octameric PA63 variants and PA63F427A mutant. The F427 residues form a hydrophobic constriction region inside the channel, known as the "ϕ-clamp." We show that the cationic blockers interact with PA63 through a combination of forces. Analysis of the binding reaction kinetics suggests the involvement of cation-π, Coulomb, and salt-concentration-independent π-π or hydrophobic interactions in the cationic cyclodextrin binding. It is possible that these blockers bind to the ϕ-clamp and are also stabilized by the Coulomb interactions of their terminal amino groups with the water-exposed negatively charged channel residues. In PA63F427A, only the suggested Coulomb component of the cyclodextrin interaction remains. Methyltriphenylphosphonium ion and G0 polyamidoamine dendrimer, despite being positively charged, interact primarily with the ϕ-clamp. We also show that seven- and eightfold symmetric cyclodextrins effectively block the heptameric and octameric forms of PA63 interchangeably, adding flexibility to the earlier formulated blocker/target symmetry match requirement.
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Wilson JW, Rolland AD, Klausen GM, Prell JS. Ion Mobility-Mass Spectrometry Reveals That α-Hemolysin from Staphylococcus aureus Simultaneously Forms Hexameric and Heptameric Complexes in Detergent Micelle Solutions. Anal Chem 2019; 91:10204-10211. [PMID: 31282652 DOI: 10.1021/acs.analchem.9b02243] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Many soluble and membrane proteins form symmetrical homooligomeric complexes. However, determining the oligomeric state of protein complexes can be difficult. Alpha-hemolysin (αHL) from Staphylococcus aureus is a symmetrical homooligomeric protein toxin that forms transmembrane β-barrel pores in host cell membranes. The stable pore structure of αHL has also been exploited in vitro as a nanopore tool. Early structural experiments suggested αHL forms a hexameric pore, while more recent X-ray crystal structure and solution studies have identified a heptameric pore structure. Here, using native ion mobility-mass spectrometry (IM-MS) we find that αHL simultaneously forms hexameric and heptameric oligomers in both tetraethylene glycol monooctyl ether (C8E4) and tetradecylphosphocholine (FOS-14) detergent solutions. We also analyze intact detergent micelle-embedded αHL porelike complexes by native IM-MS without the need to fully strip the detergent micelle, which can cause significant gas-phase unfolding. The highly congested native mass spectra are deconvolved using Fourier- and Gábor-transform (FT and GT) methods to determine charge states and detergent stoichiometry distributions. The intact αHL micelle complexes are found to contain oligomeric state-proportional numbers of detergent molecules. This evidence, combined with IM data and results from vacuum molecular dynamics simulations, is consistent with both the hexamer and the heptamer forming porelike complexes. The ability of αHL to form both oligomeric states simultaneously has implications for its use as a nanopore tool and its pore formation mechanism in vivo. This study also demonstrates more generally the power of FT and GT to deconvolve the charge state and stoichiometry distributions of polydisperse ions.
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Affiliation(s)
- Jesse W Wilson
- Department of Chemistry and Biochemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403-1253 , United States
| | - Amber D Rolland
- Department of Chemistry and Biochemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403-1253 , United States
| | - Grant M Klausen
- Department of Chemistry and Biochemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403-1253 , United States
| | - James S Prell
- Department of Chemistry and Biochemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403-1253 , United States.,Materials Science Institute , University of Oregon , 1252 University of Oregon , Eugene , Oregon 97403-1252 , United States
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Yamini G, Nestorovich EM. Multivalent Inhibitors of Channel-Forming Bacterial Toxins. Curr Top Microbiol Immunol 2019; 406:199-227. [PMID: 27469304 PMCID: PMC6814628 DOI: 10.1007/82_2016_20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Rational design of multivalent molecules represents a remarkable modern tool to transform weak non-covalent interactions into strong binding by creating multiple finely-tuned points of contact between multivalent ligands and their supposed multivalent targets. Here, we describe several prominent examples where the multivalent blockers were investigated for their ability to directly obstruct oligomeric channel-forming bacterial exotoxins, such as the pore-forming bacterial toxins and B component of the binary bacterial toxins. We address problems related to the blocker/target symmetry match and nature of the functional groups, as well as chemistry and length of the linkers connecting the functional groups to their multivalent scaffolds. Using the anthrax toxin and AB5 toxin case studies, we briefly review how the oligomeric toxin components can be successfully disabled by the multivalent non-channel-blocking inhibitors, which are based on a variety of multivalent scaffolds.
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Affiliation(s)
- Goli Yamini
- Department of Biology, The Catholic University of America, Washington, D.C., 20064, USA
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Fischer ES, Campbell WA, Liu S, Ghirlando R, Fattah RJ, Bugge TH, Leppla SH. Bismaleimide cross-linked anthrax toxin forms functional octamers with high specificity in tumor targeting. Protein Sci 2019; 28:1059-1070. [PMID: 30942916 PMCID: PMC6511737 DOI: 10.1002/pro.3613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 04/01/2019] [Indexed: 12/12/2022]
Abstract
In recent years, anthrax toxin has been reengineered to act as a highly specific antiangiogenic cancer therapeutic, shown to kill tumors in animal models. This has been achieved by modifying protective antigen (PA) so that its activation and toxicity require the presence of two proteases, matrix metalloproteinase (MMP) and urokinase plasminogen activator (uPA), which are upregulated in tumor microenvironments. These therapeutics consist of intercomplementing PA variants, which are individually nontoxic, but form functional toxins upon complementary oligomerization. Here, we have created a dual-protease requiring PA targeting system which utilizes bismaleimide cross-linked PA (CLPA) rather than the intercomplementing PA variants. Three different CLPA agents were tested and, as expected, found to exclusively form octamers. Two of the CLPA agents have in vitro toxicities equal to those of previous intercomplementing agents, while the third CLPA agent had compromised in vitro cleavage and was significantly less cytotoxic. We hypothesize this difference was due to steric hindrance caused by cross-linking two PA monomers in close proximity to the PA cleavage site. Overall, this work advances the development and use of the PA and LF tumor-targeting system as a practical cancer therapeutic, as it provides a way to reduce the drug components of the anthrax toxin drug delivery system from three to two, which may lower the cost and simplify testing in clinical trials. HIGHLIGHT: Previously, anthrax toxin has been reengineered to act as a highly specific antiangiogenic cancer therapeutic. Here, we present a version, which utilizes bismaleimide cross-linked protective antigen (PA) rather than intercomplementing PA variants. This advances the development of anthrax toxin as a practical cancer therapeutic as it reduces the components of the drug delivery system to two, which may lower the cost and simplify testing in clinical trials.
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Affiliation(s)
- Elyse S. Fischer
- Laboratory of Parasitic DiseasesNational Institute of Allergy and Infectious DiseasesBethesdaMaryland
| | - Warren A. Campbell
- Laboratory of Parasitic DiseasesNational Institute of Allergy and Infectious DiseasesBethesdaMaryland
| | - Shihui Liu
- Oral and Pharyngeal Cancer BranchNational Institute of Dental and Craniofacial ResearchBethesdaMaryland
| | - Rodolfo Ghirlando
- Laboratory of Molecular BiologyNational Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesdaMaryland, 20892
| | - Rasem J. Fattah
- Laboratory of Parasitic DiseasesNational Institute of Allergy and Infectious DiseasesBethesdaMaryland
| | - Thomas H. Bugge
- Oral and Pharyngeal Cancer BranchNational Institute of Dental and Craniofacial ResearchBethesdaMaryland
| | - Stephen H. Leppla
- Laboratory of Parasitic DiseasesNational Institute of Allergy and Infectious DiseasesBethesdaMaryland
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Mirhaj H, Honari H, Zamani E. Evaluation of immune response to recombinant Bacillus anthracis LFD1-PA4 chimeric protein. IRANIAN JOURNAL OF VETERINARY RESEARCH 2019; 20:112-119. [PMID: 31531033 PMCID: PMC6716276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 12/27/2018] [Accepted: 01/01/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Anthrax is a particularly dangerous infectious disease that affects humans and livestock. Efficacious vaccines that can rapidly induce a long-term immune response are required to prevent anthrax infection in humans. Domains 4 and 1 of the protective antigen (PA) and lethal factor (LF), respectively, have very high antigenic properties. AIMS In this experimental study, the pET28a-lfD1-pa4 expression vector was designed, constructed and transferred into E. coli BL21 (DE3) plysS. METHODS For this purpose, pa4 gene was amplified by polymerase chain reaction (PCR) and cloned in a pGEM T-easy vector. The pGEM-pa4 and pGEM-lfD1 were digested by XbaI and HindIII enzymes. The ligation reaction was performed by ligase T4 enzyme and the gene cassette, lfD1-pa4, was subcloned in pET28a and transferred to E. coli BL21 (DE3) PlysS. Expression and purification of chimeric proteins were confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting techniques. The chimera LFD1-PA4 and mixed LFD1+PA4 proteins were injected four times into mice and antibody production was relativity evaluated by enzyme-linked immunosorbent assay (ELISA) test. RESULTS The results showed that both chimeric and mixed proteins are immunogenic, but LFD1-PA4 has a higher potential to stimulate mice immune system. CONCLUSION LFD1-PA4 chimeric protein induced a higher immune response than LFD1+PA4 mixed protein and elicited antibody responses to LF and edema factor (EF), therefore, it holds promise to be a more effective trivalent vaccine candidate to use in anthrax prevention.
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Affiliation(s)
- H. Mirhaj
- Ph.D. Student in Nano Biotechnology, Department of Biology, Faculty of Basic Science, Imam Hossein University, Tehran, Iran
| | - H. Honari
- Department of Biology, Faculty of Basic Science, Imam Hossein University, Tehran, Iran
| | - E. Zamani
- MSc Student in Cellular and Molecular Biology, Department of Biology, Faculty of Basic Science, Imam Hossein University, Tehran, Iran
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40
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Gogoi H, Mani R, Bhatnagar R. A niosome formulation modulates the Th1/Th2 bias immune response in mice and also provides protection against anthrax spore challenge. Int J Nanomedicine 2018; 13:7427-7440. [PMID: 30532531 PMCID: PMC6241689 DOI: 10.2147/ijn.s153150] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Introduction In this study, we have investigated the immunogenicity and protective efficacy of a niosomal formulation encapsulating protective antigen (PA) and PA domain 4 (D4) of Bacillus anthracis. Methods Nonionic surfactant–based vesicles (NISV) + PA and NISV + D4 were prepared from span-60 and cholesterol by reverse-phase evaporation method and were evaluated for in vitro characteristics and immunological studies. Results Particle characterization using transmission electron microscopy and atomic force microscopy analysis showed that the niosomal formulation was spherical in shape. The entrapment efficiency values were calculated to be 58.5% and 44.75% for PA and D4, respectively. Confocal microscopy and flow cytometry studies showed an enhanced uptake of antigen in THP1 macrophages by niosome as compared to antigen only. An in vitro release assay showed a burst release of antigen from niosome within 24 hours followed by a gradual release for 144 hours. Immunological studies showed that both PA- and D4-encapsulated niosome elicited a robust IgG titer. Antibody isotyping and cytokine profile showed that NISV + PA and NISV + D4 enhanced both Th1 and Th2 responses in mice, suggesting a mixed Th1/Th2 response. Both NISV + PA and NISV + D4 elicited high levels of anti-inflammatory cytokine interleukin-10 with low levels of pro-inflammatory cytokine tumor necrosis factor-α, suggesting the anti-inflammatory property of niosome. Both the niosomal formulations were also able to confer protection against BA infection as compared to only PA and D4. Conclusion PA and D4 encapsulated NISV formulation could modulate both the Th1 and Th2 adaptive immune system and was found to be a better prophylactic against anthrax.
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Affiliation(s)
- Himanshu Gogoi
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India,
| | - Rajesh Mani
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India,
| | - Rakesh Bhatnagar
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India,
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Cleary SP, Li H, Bagal D, Loo JA, Campuzano IDG, Prell JS. Extracting Charge and Mass Information from Highly Congested Mass Spectra Using Fourier-Domain Harmonics. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:2067-2080. [PMID: 30003534 PMCID: PMC6330157 DOI: 10.1007/s13361-018-2018-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 05/30/2018] [Accepted: 06/21/2018] [Indexed: 05/20/2023]
Abstract
Native mass spectra of large, polydisperse biomolecules with repeated subunits, such as lipoprotein Nanodiscs, can often be challenging to analyze by conventional methods. The presence of tens of closely spaced, overlapping peaks in these mass spectra can make charge state, total mass, or subunit mass determinations difficult to measure by traditional methods. Recently, we introduced a Fourier Transform-based algorithm that can be used to deconvolve highly congested mass spectra for polydisperse ion populations with repeated subunits and facilitate identification of the charge states, subunit mass, charge-state-specific, and total mass distributions present in the ion population. Here, we extend this method by investigating the advantages of using overtone peaks in the Fourier spectrum, particularly for mass spectra with low signal-to-noise and poor resolution. This method is illustrated for lipoprotein Nanodisc mass spectra acquired on three common platforms, including the first reported native mass spectrum of empty "large" Nanodiscs assembled with MSP1E3D1 and over 300 noncovalently associated lipids. It is shown that overtone peaks contain nearly identical stoichiometry and charge state information to fundamental peaks but can be significantly better resolved, resulting in more reliable reconstruction of charge-state-specific mass spectra and peak width characterization. We further demonstrate how these parameters can be used to improve results from Bayesian spectral fitting algorithms, such as UniDec. Graphical Abstract ᅟ.
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Affiliation(s)
- Sean P Cleary
- Department of Chemistry and Biochemistry, 1253 University of Oregon, Eugene, OR, 97403-1253, USA
| | - Huilin Li
- Department of Chemistry and Biochemistry, Department of Biological Chemistry, University of California, UCLA/DOE Institute for Genomics and Proteomics, Los Angeles, Los Angeles, CA, 90095, USA
| | - Dhanashri Bagal
- Amgen Discovery Research, Amgen, Inc., 1120 Veterans Blvd, South San Francisco, CA, 94080, USA
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, Department of Biological Chemistry, University of California, UCLA/DOE Institute for Genomics and Proteomics, Los Angeles, Los Angeles, CA, 90095, USA
| | - Iain D G Campuzano
- Molecular Structure and Characterization, Amgen, Inc., Thousand Oaks, CA, 91320, USA
| | - James S Prell
- Department of Chemistry and Biochemistry, 1253 University of Oregon, Eugene, OR, 97403-1253, USA.
- Materials Science Institute, 1252 University of Oregon, Eugene, OR, 97403-1252, USA.
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Scott H, Huang W, Bann JG, Taylor DJ. Advances in structure determination by cryo-EM to unravel membrane-spanning pore formation. Protein Sci 2018; 27:1544-1556. [PMID: 30129169 PMCID: PMC6194281 DOI: 10.1002/pro.3454] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 06/10/2018] [Accepted: 06/11/2018] [Indexed: 01/03/2023]
Abstract
The beta pore-forming proteins (β-PFPs) are a large class of polypeptides that are produced by all Kingdoms of life to contribute to their species' own survival. Pore assembly is a sophisticated multi-step process that includes receptor/membrane recognition and oligomerization events, and is ensued by large-scale structural rearrangements, which facilitate maturation of a prepore into a functional membrane spanning pore. A full understanding of pore formation, assembly, and maturation has traditionally been hindered by a lack of structural data; particularly for assemblies representing differing conformations of functional pores. However, recent advancements in cryo-electron microscopy (cryo-EM) techniques have provided the opportunity to delineate the structures of such flexible complexes, and in different states, to near-atomic resolution. In this review, we place a particular emphasis on the use of cryo-EM to uncover the mechanistic details including architecture, activation, and maturation for some of the prominent members of this family.
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Affiliation(s)
- Harry Scott
- Department of PharmacologyCase Western Reserve UniversityClevelandOhio44106
| | - Wei Huang
- Department of PharmacologyCase Western Reserve UniversityClevelandOhio44106
| | - James G. Bann
- Department of ChemistryWichita State UniversityWichitaKansas67260
| | - Derek J. Taylor
- Department of PharmacologyCase Western Reserve UniversityClevelandOhio44106
- Department of BiochemistryCase Western Reserve UniversityClevelandOhio44106
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Kalu N, Atsmon-Raz Y, Momben Abolfath S, Lucas L, Kenney C, Leppla SH, Tieleman DP, Nestorovich EM. Effect of late endosomal DOBMP lipid and traditional model lipids of electrophysiology on the anthrax toxin channel activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2192-2203. [PMID: 30409515 DOI: 10.1016/j.bbamem.2018.08.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/09/2018] [Accepted: 08/19/2018] [Indexed: 01/26/2023]
Abstract
Anthrax toxin action requires triggering of natural endocytic transport mechanisms whereby the binding component of the toxin forms channels (PA63) within endosomal limiting and intraluminal vesicle membranes to deliver the toxin's enzymatic components into the cytosol. Membrane lipid composition varies at different stages of anthrax toxin internalization, with intraluminal vesicle membranes containing ~70% of anionic bis(monoacylglycero)phosphate lipid. Using model bilayer measurements, we show that membrane lipids can have a strong effect on the anthrax toxin channel properties, including the channel-forming activity, voltage-gating, conductance, selectivity, and enzymatic factor binding. Interestingly, the highest PA63 insertion rate was observed in bis(monoacylglycero)phosphate membranes. The molecular dynamics simulation data show that the conformational properties of the channel are different in bis(monoacylglycero)phosphate compared to PC, PE, and PS lipids. The anthrax toxin protein/lipid bilayer system can be advanced as a novel robust model to directly investigate lipid influence on membrane protein properties and protein/protein interactions.
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Affiliation(s)
- Nnanya Kalu
- Department of Biology, The Catholic University of America, 620 Michigan Ave NE, Washington 20064, DC, USA
| | - Yoav Atsmon-Raz
- Department of Biological Sciences, Centre for Molecular Simulation, University of Calgary, 2500 University Drive NW, Calgary T2N 1N4, Alberta, Canada.
| | - Sanaz Momben Abolfath
- Department of Biology, The Catholic University of America, 620 Michigan Ave NE, Washington 20064, DC, USA
| | - Laura Lucas
- Department of Biology, The Catholic University of America, 620 Michigan Ave NE, Washington 20064, DC, USA
| | - Clare Kenney
- Department of Biology, The Catholic University of America, 620 Michigan Ave NE, Washington 20064, DC, USA
| | - Stephen H Leppla
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda 20892, MD, USA
| | - D Peter Tieleman
- Department of Biological Sciences, Centre for Molecular Simulation, University of Calgary, 2500 University Drive NW, Calgary T2N 1N4, Alberta, Canada
| | - Ekaterina M Nestorovich
- Department of Biology, The Catholic University of America, 620 Michigan Ave NE, Washington 20064, DC, USA.
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Paliga D, Raudzus F, Leppla SH, Heumann R, Neumann S. Lethal Factor Domain-Mediated Delivery of Nurr1 Transcription Factor Enhances Tyrosine Hydroxylase Activity and Protects from Neurotoxin-Induced Degeneration of Dopaminergic Cells. Mol Neurobiol 2018; 56:3393-3403. [PMID: 30121937 PMCID: PMC6476859 DOI: 10.1007/s12035-018-1311-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 08/08/2018] [Indexed: 12/31/2022]
Abstract
The orphan transcription factor nuclear receptor-related 1 protein (Nurr1, also known as NR4A2) plays a key role in embryonic development and maintenance of mesencephalic dopaminergic neurons in the substantia nigra. Nurr1 deficiency is associated with Parkinson’s disease where dopaminergic neurons degenerate suggesting that counter-regulation of Nurr1 activity may have therapeutic effects. Here, we bacterially expressed and isolated a human Nurr1 fusion protein containing a N-terminal cell delivery domain derived from detoxified anthrax lethal factor followed by wild type ubiquitin with deubiquitinating enzyme recognition site for intracellular cleavage. Addition of the Nurr1 fusion protein to dopaminergic SH-SY5Y cells generated a cleaved, cytosolic Nurr1-containing fragment which was associated with increased levels of tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis. Promoter-activity assays confirmed that exposure of cells to full-length Nurr1 fusion protein activated not only its cognate human tyrosine hydroxylase promoter but also the corresponding mouse sequence, although at a reduced efficiency. Using 6-hydroxydopamine as a dopaminergic cell specific neurotoxin, we demonstrate that full-length Nurr1 fusion protein promotes a concentration-dependent protection from this toxic insult. Altogether, the enhancement of tyrosine hydroxylase in naïve dopaminergic cells and the protective effects in a cellular model of Parkinson’s disease suggest that full-length Nurr1 fusion protein may contribute to the development of a novel concept of protein-based therapy.
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Affiliation(s)
- Dennis Paliga
- Department of Biochemistry II - Molecular Neurobiochemistry, Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Fabian Raudzus
- Department of Biochemistry II - Molecular Neurobiochemistry, Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Stephen H Leppla
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Rolf Heumann
- Department of Biochemistry II - Molecular Neurobiochemistry, Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, 44801, Bochum, Germany.
| | - Sebastian Neumann
- Department of Biochemistry II - Molecular Neurobiochemistry, Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, 44801, Bochum, Germany
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45
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Hartmann S, Lopez Cruz R, Alameh S, Ho CLC, Rabideau A, Pentelute BL, Bradley KA, Martchenko M. Characterization of Novel Piperidine-Based Inhibitor of Cathepsin B-Dependent Bacterial Toxins and Viruses. ACS Infect Dis 2018; 4:1235-1245. [PMID: 29749721 DOI: 10.1021/acsinfecdis.8b00053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Exploiting the host endocytic trafficking pathway is a common mechanism by which bacterial exotoxins gain entry to exert virulent effects upon the host cells. A previous study identified a small-molecule, 1-(2,6-dimethyl-1-piperidinyl)-3-[(2-isopropyl-5-methylcyclohexyl)oxy]-2-propanol, that blocks the process of anthrax lethal toxin (LT) cytotoxicity. Here, we report the characterization of the bioactivity of this compound, which we named RC1. We found that RC1 protected host cells independently of LT concentration and also blocked intoxication by other bacterial exotoxins, suggesting that the target of the compound is a host factor. Using the anthrax LT intoxication pathway as a reference, we show that while anthrax toxin is able to bind to cells and establish an endosomal pore in the presence of the drug, the toxin is unable to translocate into the cytosol. We demonstrate that RC1 does not inhibit the toxin directly but rather reduces the enzymatic activity of host cathepsin B that mediates the escape of toxins into the cytoplasm from late endosomes. We demonstrate that the pathogenicity of Human cytomegalovirus and Herpes simplex virus 1, which relies on cathepsin B protease activity, is reduced by RC1. This study reveals the potential of RC1 as a broad-spectrum host-oriented therapy against several aggressive and deadly pathogens.
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Affiliation(s)
- Stella Hartmann
- School of Applied Life Sciences, Keck Graduate Institute, 535 Watson Drive, Claremont, California 91711, United States
| | - Renae Lopez Cruz
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, 609 Charles E Young Drive East, Los Angeles, California 90095, United States
| | - Saleem Alameh
- School of Applied Life Sciences, Keck Graduate Institute, 535 Watson Drive, Claremont, California 91711, United States
| | - Chi-Lee C. Ho
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, 609 Charles E Young Drive East, Los Angeles, California 90095, United States
| | - Amy Rabideau
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Bradley L. Pentelute
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Kenneth A. Bradley
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, 609 Charles E Young Drive East, Los Angeles, California 90095, United States
| | - Mikhail Martchenko
- School of Applied Life Sciences, Keck Graduate Institute, 535 Watson Drive, Claremont, California 91711, United States
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Andreou A, Giastas P, Christoforides E, Eliopoulos EE. Structural and Evolutionary Insights within the Polysaccharide Deacetylase Gene Family of Bacillus anthracis and Bacillus cereus. Genes (Basel) 2018; 9:E386. [PMID: 30065210 PMCID: PMC6115787 DOI: 10.3390/genes9080386] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/24/2018] [Accepted: 07/25/2018] [Indexed: 02/06/2023] Open
Abstract
Functional and folding constraints impose interdependence between interacting sites along the protein chain that are envisaged through protein sequence evolution. Studying the influence of structure in phylogenetic models requires detailed and reliable structural models. Polysaccharide deacetylases (PDAs), members of the carbohydrate esterase family 4, perform mainly metal-dependent deacetylation of O- or N-acetylated polysaccharides such as peptidoglycan, chitin and acetylxylan through a conserved catalytic core termed the NodB homology domain. Genomes of Bacillus anthracis and its relative Bacillus cereus contain multiple genes of putative or known PDAs. A comparison of the functional domains of the recently determined PDAs from B. anthracis and B. cereus and multiple amino acid and nucleotide sequence alignments and phylogenetic analysis performed on these closely related species showed that there were distinct differences in binding site formation, despite the high conservation on the protein sequence, the folding level and the active site assembly. This may indicate that, subject to biochemical verification, the binding site-forming sequence fragments are under functionally driven evolutionary pressure to accommodate and recognize distinct polysaccharide residues according to cell location, use, or environment. Finally, we discuss the suggestion of the paralogous nature of at least two genes of B. anthracis, ba0330 and ba0331, via specific differences in gene sequence, protein structure, selection pressure and available localization patterns. This study may contribute to understanding the mechanisms under which sequences evolve in their structures and how evolutionary processes enable structural variations.
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Affiliation(s)
- Athena Andreou
- Department of Biotechnology, Laboratory of Genetics, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
| | - Petros Giastas
- Department of Neurobiology, Hellenic Pasteur Institute, Vasilissis Sofias 127, 11521 Athens, Greece.
| | - Elias Christoforides
- Department of Biotechnology, Laboratory of Genetics, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
| | - Elias E Eliopoulos
- Department of Biotechnology, Laboratory of Genetics, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
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Elliott AG, Harper CC, Lin HW, Williams ER. Mass, mobility and MS n measurements of single ions using charge detection mass spectrometry. Analyst 2018. [PMID: 28636005 DOI: 10.1039/c7an00618g] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Charge detection mass spectrometry is used to measure the mass, charge, MSn and mobility of an individual ion produced by electrospray ionization of a 8 MDa polyethylene glycol sample. The charge detection mass spectrometer is an electrostatic ion trap that uses cone electrodes and a single tube detector and can detect ions for up to the full trapping time of 4.0 s. The time-domain signal induced on the detector tube by a single multiply charged ion can be complex owing to sequential fragmentation of the original precursor ion as well as increasing oscillation frequencies of the single ion owing to collisions with background gas that reduce the kinetic energy of the ion inside the trap. Simulations show that the ratio of the time for the ion to turn around inside the cone region of the trap to the time for the ion to travel through the detector tube is constant with m/z and increases with the ion energy per charge. By measuring this ratio, the kinetic energy of an ion can be obtained with good precision (∼1%) and this method to measure ion kinetic energies eliminates the necessity of ion energy selection prior to trapping for high precision mass measurement of large molecules in complex mixtures. This method also makes it possible to measure the masses of each sequential fragment ion formed from the original precursor ion. MS7 of a single multiply charged PEG molecule is demonstrated, and from these ion energy measurements and effects of collisions on the ion motion inside the trap, information about the ion mobility of the precursor ion and its fragments is obtained.
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Affiliation(s)
- Andrew G Elliott
- Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
| | - Conner C Harper
- Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
| | - Haw-Wei Lin
- Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
| | - Evan R Williams
- Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
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Certhrax Is an Antivirulence Factor for the Anthrax-Like Organism Bacillus cereus Strain G9241. Infect Immun 2018; 86:IAI.00207-18. [PMID: 29610258 DOI: 10.1128/iai.00207-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 03/28/2018] [Indexed: 11/20/2022] Open
Abstract
Bacillus cereus G9241 caused a life-threatening anthrax-like lung infection in a previously healthy human. This strain harbors two large virulence plasmids, pBCXO1 and pBC210, that are absent from typical B. cereus isolates. The pBCXO1 plasmid is nearly identical to pXO1 from Bacillus anthracis and carries genes (pagA1, lef, and cya) for anthrax toxin components (protective antigen [called PA1 in G9241], lethal factor [LF], and edema factor [EF], respectively). The plasmid also has an intact hyaluronic acid capsule locus. The pBC210 plasmid has a tetrasaccharide capsule locus, a gene for a PA1 homolog called PA2 (pagA2), and a gene (cer) for Certhrax, an ADP-ribosyltransferase toxin that inactivates vinculin. LF, EF, and Certhrax require PA for entry into cells. In this study, we asked what role PA1, PA2, LF, and Certhrax play in the pathogenicity of G9241. To answer this, we generated isogenic deletion mutations in the targeted toxin gene components and then assessed the strains for virulence in highly G9241-susceptible (A/J) and moderately G9241-sensitive (C57BL/6) mice. We found that full virulence of G9241 required PA1 and LF, while PA2 contributed minimally to pathogenesis of G9241 but could not functionally replace PA1 as a toxin-binding subunit in vivo Surprisingly, we discovered that Certhrax attenuated the virulence of G9241; i.e., a Δcer Δlef mutant strain was more virulent than a Δlef mutant strain following subcutaneous inoculation of A/J mice. Moreover, the enzymatic activity of Certhrax contributed to this phenotype. We concluded that Certhrax acts as an antivirulence factor in the anthrax-like organism B. cereus G9241.
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Abstract
Bacillus anthracis, the anthrax agent, is a member of the Bacillus cereus sensu lato group, which includes invasive pathogens of mammals or insects as well as nonpathogenic environmental strains. The genes for anthrax pathogenesis are located on two large virulence plasmids. Similar virulence plasmids have been acquired by other B. cereus strains and enable the pathogenesis of anthrax-like diseases. Among the virulence factors of B. anthracis is the S-layer-associated protein BslA, which endows bacilli with invasive attributes for mammalian hosts. BslA surface display and function are dependent on the bacterial S-layer, whose constituents assemble by binding to the secondary cell wall polysaccharide (SCWP) via S-layer homology (SLH) domains. B. anthracis and other pathogenic B. cereus isolates harbor genes for the secretion of S-layer proteins, for S-layer assembly, and for synthesis of the SCWP. We review here recent insights into the assembly and function of the S-layer and the SCWP.
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Affiliation(s)
- Dominique Missiakas
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois 60649.,Department of Microbiology, University of Chicago, Chicago, Illinois 60637;
| | - Olaf Schneewind
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois 60649.,Department of Microbiology, University of Chicago, Chicago, Illinois 60637;
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50
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Lahousse M, Park HC, Lee SC, Ha NR, Jung IP, Schlesinger SR, Shackelford K, Yoon MY, Kim SK. Inhibition of anthrax lethal factor by ssDNA aptamers. Arch Biochem Biophys 2018; 646:16-23. [PMID: 29580944 DOI: 10.1016/j.abb.2018.03.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 03/04/2018] [Accepted: 03/22/2018] [Indexed: 01/12/2023]
Abstract
Anthrax is caused by Bacillus anthracis, a bacterium that is able to secrete the toxins protective antigen, edema factor and lethal factor. Due to the high level of secretion from the bacteria and its severe virulence, lethal factor (LF) has been sought as a biomarker for detecting bacterial infection and as an effective target to neutralize toxicity. In this study, we found three aptamers, and binding affinity was determined by fluorescently labeled aptamers. One of the aptamers exhibited high affinity, with a Kd value of 11.0 ± 2.7 nM, along with low cross reactivity relative to bovine serum albumin and protective antigen. The therapeutic functionality of the aptamer was examined by assessing the inhibition of LF protease activity against a mitogen-activated protein kinase kinase. The aptamer appears to be an effective inhibitor of LF with an IC50 value of 15 ± 1.5 μM and approximately 85% cell viability, suggesting that this aptamer provides a potential clue for not only development of a sensitive diagnostic device of B. anthracis infection but also the design of novel inhibitors of LF.
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Affiliation(s)
- Mieke Lahousse
- The Institute of Biomedical Studies, and the Department of Chemistry and Biochemistry, Baylor University, Waco, TX, 76798-7348, USA
| | - Hae-Chul Park
- Department of Chemistry, Hanyang University, Seoul, 133-791, Republic of Korea
| | - Sang-Choon Lee
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
| | - Na-Reum Ha
- Department of Chemistry, Hanyang University, Seoul, 133-791, Republic of Korea
| | - In-Pil Jung
- Department of Chemistry, Hanyang University, Seoul, 133-791, Republic of Korea
| | - Sara R Schlesinger
- The Institute of Biomedical Studies, and the Department of Chemistry and Biochemistry, Baylor University, Waco, TX, 76798-7348, USA
| | - Kaylin Shackelford
- Department of Natural Sciences, Northeastern State University, Tahlequah, OK 74464, USA
| | - Moon-Young Yoon
- Department of Chemistry, Hanyang University, Seoul, 133-791, Republic of Korea
| | - Sung-Kun Kim
- Department of Natural Sciences, Northeastern State University, Tahlequah, OK 74464, USA.
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