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Fisher DJ, Beare PA. Recent advances in genetic systems in obligate intracellular human-pathogenic bacteria. Front Cell Infect Microbiol 2023; 13:1202245. [PMID: 37404720 PMCID: PMC10315504 DOI: 10.3389/fcimb.2023.1202245] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 05/22/2023] [Indexed: 07/06/2023] Open
Abstract
The ability to genetically manipulate a pathogen is fundamental to discovering factors governing host-pathogen interactions at the molecular level and is critical for devising treatment and prevention strategies. While the genetic "toolbox" for many important bacterial pathogens is extensive, approaches for modifying obligate intracellular bacterial pathogens were classically limited due in part to the uniqueness of their obligatory lifestyles. Many researchers have confronted these challenges over the past two and a half decades leading to the development of multiple approaches to construct plasmid-bearing recombinant strains and chromosomal gene inactivation and deletion mutants, along with gene-silencing methods enabling the study of essential genes. This review will highlight seminal genetic achievements and recent developments (past 5 years) for Anaplasma spp., Rickettsia spp., Chlamydia spp., and Coxiella burnetii including progress being made for the still intractable Orientia tsutsugamushi. Alongside commentary of the strengths and weaknesses of the various approaches, future research directions will be discussed to include methods for C. burnetii that should have utility in the other obligate intracellular bacteria. Collectively, the future appears bright for unraveling the molecular pathogenic mechanisms of these significant pathogens.
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Affiliation(s)
- Derek J. Fisher
- School of Biological Sciences, Southern Illinois University, Carbondale, IL, United States
| | - Paul A. Beare
- Rocky Mountain Laboratory, National Institute of Health, Hamilton, MT, United States
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de Campos LJ, Seleem MA, Feng J, Pires de Oliveira KM, de Andrade Dos Santos JV, Hayer S, Clayton JB, Kathi S, Fisher DJ, Ouellette SP, Conda-Sheridan M. Design, Biological Evaluation, and Computer-Aided Analysis of Dihydrothiazepines as Selective Antichlamydial Agents. J Med Chem 2023; 66:2116-2142. [PMID: 36696579 PMCID: PMC10056257 DOI: 10.1021/acs.jmedchem.2c01894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Chlamydia trachomatis (CT) causes the most prevalent sexually transmitted bacterial disease in the United States. The lack of drug selectivity is one of the main challenges of the current antichlamydial pharmacotherapy. The metabolic needs of CT are controlled, among others, by cylindrical proteases and their chaperones (e.g., ClpX). It has been shown that dihydrothiazepines can disrupt CT-ClpXP. Based on this precedent, we synthesized a dihydrothiazepine library and characterized its antichlamydial activity using a modified semi-high-throughput screening assay. Then, we demonstrated their ability to inhibit ClpX ATPase activity in vitro, supporting ClpX as a target. Further, our lead compound displayed a promising selectivity profile against CT, acceptable cytotoxicity, no mutagenic potential, and good in vitro stability. A two-dimensional quantitative structure-activity relationship (2D QSAR) model was generated as a support tool in the identification of more potent antichlamydial molecules. This study suggests dihydrothiazepines are a promising starting point for the development of new and selective antichlamydial drugs.
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Affiliation(s)
- Luana Janaína de Campos
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Mohamed A Seleem
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Jiachen Feng
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Kelly Mari Pires de Oliveira
- Faculty of Biological and Environmental Science, Federal University of Grande Dourados, Dourados, MS 79804-970, Brazil
| | | | - Shivdeep Hayer
- Department of Biology, University of Nebraska at Omaha, Omaha, Nebraska 68182, United States
| | - Jonathan B Clayton
- Department of Biology, University of Nebraska at Omaha, Omaha, Nebraska 68182, United States
- Department of Food Science and Technology, University of Nebraska─Lincoln, Lincoln, Nebraska 68588, United States
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
- Nebraska Food for Health Center, University of Nebraska─Lincoln, Lincoln, Nebraska 68508, United States
| | - Sharvath Kathi
- School of Biological Sciences, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Derek J Fisher
- School of Biological Sciences, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Scot P Ouellette
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Martin Conda-Sheridan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
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Abstract
Despite having a highly reduced genome, Chlamydia trachomatis undergoes a complex developmental cycle in which the bacteria differentiate between the following two functionally and morphologically distinct forms: the infectious, nonreplicative elementary body (EB) and the noninfectious, replicative reticulate body (RB). The transitions between EBs and RBs are not mediated by division events that redistribute intracellular proteins. Rather, both primary (EB to RB) and secondary (RB to EB) differentiation likely require bulk protein turnover. One system for targeted protein degradation is the trans-translation system for ribosomal rescue, where polypeptides stalled during translation are marked with an SsrA tag encoded by a hybrid tRNA-mRNA, tmRNA. ClpX recognizes the SsrA tag, leading to ClpXP-mediated degradation. We hypothesize that ClpX functions in chlamydial differentiation through targeted protein degradation. We found that mutation of a key residue (R230A) within the specific motif in ClpX associated with the recognition of SsrA-tagged substrates resulted in abrogated secondary differentiation while not reducing chlamydial replication or developmental cycle progression as measured by transcripts. Furthermore, inhibition of trans-translation through chemical and targeted genetic approaches also impeded chlamydial development. Knockdown of tmRNA and subsequent complementation with an allele mutated in the SsrA tag closely phenocopied the overexpression of ClpXR230A, thus suggesting that ClpX recognition of SsrA-tagged substrates plays a critical function in secondary differentiation. Taken together, these data provide mechanistic insight into the requirements for transitions between chlamydial developmental forms. IMPORTANCE Chlamydia trachomatis is the leading cause of bacterial sexually transmitted infections and preventable infectious blindness. This unique organism undergoes developmental transitions between infectious, nondividing forms and noninfectious, dividing forms. Therefore, the chlamydial developmental cycle is an attractive target for Chlamydia-specific antibiotics, which would minimize effects of broad-spectrum antibiotics on the spread of antibiotic resistance in other organisms. However, the lack of knowledge about chlamydial development on a molecular level impedes the identification of specific, druggable targets. This work describes a mechanism through which both the fundamental processes of trans-translation and proteomic turnover by ClpXP contribute to chlamydial differentiation, a critical facet of chlamydial growth and survival. Given the almost universal presence of trans-translation and ClpX in eubacteria, this mechanism may be conserved in developmental cycles of other bacterial species. Additionally, this study expands the fields of trans-translation and Clp proteases by emphasizing the functional diversity of these systems throughout bacterial evolution.
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Bortezomib Eliminates Persistent Chlamydia trachomatis Infection through Rapid and Specific Host Cell Apoptosis. Int J Mol Sci 2022; 23:ijms23137434. [PMID: 35806436 PMCID: PMC9267172 DOI: 10.3390/ijms23137434] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/25/2022] [Accepted: 07/02/2022] [Indexed: 12/04/2022] Open
Abstract
Chlamydia trachomatis, a parasitic intracellular bacterium, is a major human pathogen that causes millions of trachoma, sexually transmitted infections, and pneumonia cases worldwide. Previously, peptidomimetic inhibitors consisting of a hydrophobic dipeptide derivative exhibited significant inhibitory effects against chlamydial growth. Based on this finding, this study showed that both bortezomib (BTZ) and ixazomib (IXA), anticancer drugs characterized by proteasome inhibitors, have intensive inhibitory activity against Chlamydia. Both BTZ and IXA consisted of hydrophobic dipeptide derivatives and strongly restricted the growth of Chlamydia (BTZ, IC50 = 24 nM). In contrast, no growth inhibitory effect was observed for other nonintracellular parasitic bacteria, such as Escherichia coli. BTZ and IXA appeared to inhibit chlamydial growth bacteriostatically via electron microscopy. Surprisingly, Chlamydia-infected cells that induced a persistent infection state were selectively eliminated by BTZ treatment, whereas uninfected cells survived. These results strongly suggested the potential of boron compounds based on hydrophobic dipeptides for treating chlamydial infections, including persistent infections, which may be useful for future therapeutic use in chlamydial infectious diseases.
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Huang Y, Wurihan W, Lu B, Zou Y, Wang Y, Weldon K, Fondell JD, Lai Z, Wu X, Fan H. Robust Heat Shock Response in Chlamydia Lacking a Typical Heat Shock Sigma Factor. Front Microbiol 2022; 12:812448. [PMID: 35046926 PMCID: PMC8762339 DOI: 10.3389/fmicb.2021.812448] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 12/02/2021] [Indexed: 11/13/2022] Open
Abstract
Cells reprogram their transcriptome in response to stress, such as heat shock. In free-living bacteria, the transcriptomic reprogramming is mediated by increased DNA-binding activity of heat shock sigma factors and activation of genes normally repressed by heat-induced transcription factors. In this study, we performed transcriptomic analyses to investigate heat shock response in the obligate intracellular bacterium Chlamydia trachomatis, whose genome encodes only three sigma factors and a single heat-induced transcription factor. Nearly one-third of C. trachomatis genes showed statistically significant (≥1.5-fold) expression changes 30 min after shifting from 37 to 45°C. Notably, chromosomal genes encoding chaperones, energy metabolism enzymes, type III secretion proteins, as well as most plasmid-encoded genes, were differentially upregulated. In contrast, genes with functions in protein synthesis were disproportionately downregulated. These findings suggest that facilitating protein folding, increasing energy production, manipulating host activities, upregulating plasmid-encoded gene expression, and decreasing general protein synthesis helps facilitate C. trachomatis survival under stress. In addition to relieving negative regulation by the heat-inducible transcriptional repressor HrcA, heat shock upregulated the chlamydial primary sigma factor σ66 and an alternative sigma factor σ28. Interestingly, we show for the first time that heat shock downregulates the other alternative sigma factor σ54 in a bacterium. Downregulation of σ54 was accompanied by increased expression of the σ54 RNA polymerase activator AtoC, thus suggesting a unique regulatory mechanism for reestablishing normal expression of select σ54 target genes. Taken together, our findings reveal that C. trachomatis utilizes multiple novel survival strategies to cope with environmental stress and even to replicate. Future strategies that can specifically target and disrupt Chlamydia’s heat shock response will likely be of therapeutic value.
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Affiliation(s)
- Yehong Huang
- Department of Parasitology, Xiangya School of Basic Medicine, Central South University, Changsha, China.,Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Wurihan Wurihan
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Bin Lu
- Department of Parasitology, Xiangya School of Basic Medicine, Central South University, Changsha, China.,Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Yi Zou
- Greehey Children's Cancer Research Institute, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Yuxuan Wang
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Korri Weldon
- Greehey Children's Cancer Research Institute, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Joseph D Fondell
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Zhao Lai
- Greehey Children's Cancer Research Institute, University of Texas Health San Antonio, San Antonio, TX, United States.,Department of Molecular Medicine, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Xiang Wu
- Department of Parasitology, Xiangya School of Basic Medicine, Central South University, Changsha, China
| | - Huizhou Fan
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
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Seleem MA, Wood NA, Brinkworth AJ, Manam S, Carabeo RA, Murthy AK, Ouellette SP, Conda-Sheridan M. In Vitro and In Vivo Activity of (Trifluoromethyl)pyridines as Anti- Chlamydia trachomatis Agents. ACS Infect Dis 2022; 8:227-241. [PMID: 34935346 PMCID: PMC9516413 DOI: 10.1021/acsinfecdis.1c00553] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Chlamydia trachomatis is the leading pathogen in sexually transmitted bacterial infections across the globe. The development of a selective treatment against this pathogen could be an attractive therapeutic option that will reduce the overuse of broad-spectrum antibiotics. Previously, we reported some sulfonylpyridine-based compounds that showed selectivity against C. trachomatis. Here, we describe a set of related compounds that display enhanced anti-chlamydial potency when compared to our early leads. We found that the active molecules are bactericidal and have no impact on Staphylococcus aureus or Escherichia coli strains. Importantly, the molecules were not toxic to mammalian cells. Furthermore, a combination of molecule 20 (the most active molecule) and azithromycin at subinhibitory concentrations acted synergistically to inhibit chlamydial growth. Molecule 20 also eradicated Chlamydia in a 3D infection model and accelerated the recovery of Chlamydia-infected mice. This work presents compounds that could be further developed to be used alone or in combination with existing treatment regimens against chlamydial infections.
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Affiliation(s)
- Mohamed A. Seleem
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Nicholas A. Wood
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Amanda J. Brinkworth
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Srikanth Manam
- Department of Pathology and Population Medicine, Midwestern University, Glendale, Arizona 85308, United States
| | - Rey A. Carabeo
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Ashlesh K. Murthy
- Department of Pathology and Population Medicine, Midwestern University, Glendale, Arizona 85308, United States
| | - Scot P. Ouellette
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Martin Conda-Sheridan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
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Inclusion Membrane Growth and Composition Are Altered by Overexpression of Specific Inclusion Membrane Proteins in Chlamydia trachomatis L2. Infect Immun 2021; 89:e0009421. [PMID: 33875478 PMCID: PMC8208519 DOI: 10.1128/iai.00094-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Chlamydia trachomatis is the leading cause of bacterial sexually transmitted infections. This obligate intracellular bacterium develops within a membrane-bound vacuole called an inclusion, which sequesters the chlamydiae from the host cytoplasm. Host-pathogen interactions at this interface are mediated by chlamydial inclusion membrane proteins (Incs). However, the specific functions of most Incs are poorly characterized. Previous work from our laboratories indicated that expressing an IncF fusion protein at high levels in C. trachomatis L2 negatively impacted inclusion expansion and progeny production. We hypothesize that some Incs function in the structure and organization of the inclusion membrane and that overexpression of those Incs will alter the composition of endogenous Incs within the inclusion membrane. Consequently, inclusion biogenesis and chlamydial development are negatively impacted. To investigate this, C. trachomatis L2 was transformed with inducible expression plasmids encoding IncF-, CT813-, or CT226-FLAG. Overexpression of IncF-FLAG or CT813-FLAG, but not CT226-FLAG, altered chlamydial development, as demonstrated by smaller inclusions, fewer progeny, and increased plasmid loss. The overexpression of CT813-FLAG reduced the detectable levels of endogenous IncE and IncG in the inclusion membrane. Notably, recruitment of sorting nexin-6, a eukaryotic protein binding partner of IncE, was also reduced after CT813 overexpression. Gene expression studies and ultrastructural analysis of chlamydial organisms demonstrated that chlamydial development was altered when CT813-FLAG was overexpressed. Overall, these data indicate that disrupting the expression of specific Incs changed the composition of Incs within the inclusion membrane and the recruitment of associated host cell proteins, which negatively impacted C. trachomatis development.
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Ouellette SP, Blay EA, Hatch ND, Fisher-Marvin LA. CRISPR Interference To Inducibly Repress Gene Expression in Chlamydia trachomatis. Infect Immun 2021; 89:e0010821. [PMID: 33875479 PMCID: PMC8373233 DOI: 10.1128/iai.00108-21] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 04/08/2021] [Indexed: 12/16/2022] Open
Abstract
The ability to inducibly repress gene expression is critical to the study of organisms, like Chlamydia, with reduced genomes in which the majority of genes are likely to be essential. We recently described the feasibility of a CRISPR interference (CRISPRi) system to inducibly repress gene expression in Chlamydia trachomatis. However, the initial system suffered from some drawbacks, primarily leaky expression of the anhydrotetracycline (aTc)-inducible dCas9 ortholog and plasmid instability, which prevented population-wide studies (e.g., transcript analyses) of the effects of knockdown. Here, we describe various modifications to the original system that have allowed us to measure gene expression changes within a transformed population of C. trachomatis serovar L2. These modifications include (i) a change in the vector backbone, (ii) the introduction of a weaker ribosome binding site driving dCas9 translation, and (iii) the addition of a degradation tag to dCas9 itself. With these changes, we demonstrate the ability to inducibly repress a target gene sequence, as measured by the absence of protein by immunofluorescence analysis and by decreased transcript levels. Importantly, the expression of dCas9 alone (i.e., without a guide RNA [gRNA]) had minimal impact on chlamydial growth or development. We also describe complementation of the knockdown effect by introducing a transcriptional fusion of the target gene 3' to dCas9. Finally, we demonstrate the functionality of a second CRISPRi system based on a dCas12 system that expands the number of potential chromosomal targets. These tools should provide the ability to study essential gene function in Chlamydia.
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Affiliation(s)
- Scot P. Ouellette
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Emmanuel A. Blay
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Nathan D. Hatch
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Laura A. Fisher-Marvin
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
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Kahne SC, Darwin KH. Structural determinants of regulated proteolysis in pathogenic bacteria by ClpP and the proteasome. Curr Opin Struct Biol 2021; 67:120-126. [PMID: 33221704 PMCID: PMC8096641 DOI: 10.1016/j.sbi.2020.09.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/25/2020] [Accepted: 09/28/2020] [Indexed: 01/05/2023]
Abstract
Bacteria use gated proteolytic machines for routine protein quality control and regulated responses to environmental conditions. This review discusses recent advances in understanding the structure and regulation of ClpP proteases, nanomachines widely distributed across bacteria, and the bacterial proteasome, a protease found in relatively few species. For both machines, activators confer substrate specificity. We highlight new data from organisms encoding two ClpP isoforms and the central role of activators as platforms for integrating regulatory signals. Because proteolytic systems contribute to survival and virulence of many bacterial pathogens, understanding their forms and functions enables new approaches to design targeted therapeutics.
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Affiliation(s)
- Shoshanna C Kahne
- New York University Robert Grossman School of Medicine, Department of Microbiology, 430 E. 29th Street, Room 312, New York, NY 10016, USA
| | - K Heran Darwin
- New York University Robert Grossman School of Medicine, Department of Microbiology, 430 E. 29th Street, Room 312, New York, NY 10016, USA.
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Acyldepsipeptide activated ClpP1P2 macromolecule of Leptospira, an ideal Achilles' heel to hamper the cell survival and deregulate ClpP proteolytic activity. Res Microbiol 2021; 172:103797. [PMID: 33460738 DOI: 10.1016/j.resmic.2021.103797] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 12/30/2020] [Accepted: 01/07/2021] [Indexed: 11/22/2022]
Abstract
Antibiotic acyldepsipeptide (ADEP) targets the bacterial ClpP serine protease and can inhibit the growth of numerous bacterial species by activating/dysregulating the protease activity within the cell. The spirochete Leptospira interrogans harbors two ClpP isoforms (LepClpP1 and LepClpP2). Supplementation of ADEP in the Leptospira growth medium resulted in the inhibition of bacterial growth. The ADEP mediated activation of the LepClpP mixture was dependent on the time allowed for the self-assembly of LepClpP1 and LepClpP2. The dynamic light scattering of the LepClpP mixture in the presence of the ADEP indicated a conformational transformation of the LepClpP machinery. Serine 98, a catalytic triad residue of the LepClpP1 in the LepClpP1P2 heterocomplex, was critical for the ADEP mediated activation. The computational prototype of the LepClpP1P2 structure suggested that the hydrophobic pockets wherein the ADEPs or the physiological chaperone ClpX predominantly dock are exclusively present in the LepClpP2 heptamer. Using the ADEP as a tool, this investigation provides an insight into the molecular function of the LepClpP1P2 in a coalition with its ATPase chaperone LepClpX. The shreds of the evidence illustrated in this investigation verify that ADEP1 possesses the ability to control the LepClpP system in an unconventional approach than the other organisms.
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The ClpX and ClpP2 Orthologs of Chlamydia trachomatis Perform Discrete and Essential Functions in Organism Growth and Development. mBio 2020; 11:mBio.02016-20. [PMID: 32873765 PMCID: PMC7468207 DOI: 10.1128/mbio.02016-20] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Chlamydia trachomatis is the leading cause of infectious blindness globally and the most reported bacterial sexually transmitted infection both domestically and internationally. Given the economic burden, the lack of an approved vaccine, and the use of broad-spectrum antibiotics for treatment of infections, an understanding of chlamydial growth and development is critical for the advancement of novel targeted antibiotics. The Clp proteins comprise an important and conserved protease system in bacteria. Our work highlights the importance of the chlamydial Clp proteins to this clinically important bacterium. Additionally, our study implicates the Clp system playing an integral role in chlamydial developmental cycle progression, which may help establish models of how Chlamydia spp. and other bacteria progress through their respective developmental cycles. Our work also contributes to a growing body of Clp-specific research that underscores the importance and versatility of this system throughout bacterial evolution and further validates Clp proteins as drug targets. Chlamydia trachomatis is an obligate intracellular bacterium that undergoes a complex developmental cycle in which the bacterium differentiates between two functionally and morphologically distinct forms, the elementary body (EB) and reticulate body (RB), each of which expresses its own specialized repertoire of proteins. Both primary (EB to RB) and secondary (RB to EB) differentiations require protein turnover, and we hypothesize that proteases are critical for mediating differentiation. The Clp protease system is well conserved in bacteria and important for protein turnover. Minimally, the system relies on a serine protease subunit, ClpP, and an AAA+ ATPase, such as ClpX, that recognizes and unfolds substrates for ClpP degradation. In Chlamydia, ClpX is encoded within an operon 3′ to clpP2. We present evidence that the chlamydial ClpX and ClpP2 orthologs are essential to organism viability and development. We demonstrate here that chlamydial ClpX is a functional ATPase and forms the expected homohexamer in vitro. Overexpression of a ClpX mutant lacking ATPase activity had a limited impact on DNA replication or secondary differentiation but, nonetheless, reduced EB viability with observable defects in EB morphology noted. Conversely, overexpression of a catalytically inactive ClpP2 mutant significantly impacted developmental cycle progression by reducing the overall number of organisms. Blocking clpP2X transcription using CRISPR interference led to a decrease in bacterial growth, and this effect was complemented in trans by a plasmid copy of clpP2. Taken together, our data indicate that ClpX and the associated ClpP2 serve distinct functions in chlamydial developmental cycle progression and differentiation.
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12
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Seleem MA, Rodrigues de Almeida N, Chhonker YS, Murry DJ, Guterres ZDR, Blocker AM, Kuwabara S, Fisher DJ, Leal ES, Martinefski MR, Bollini M, Monge ME, Ouellette SP, Conda-Sheridan M. Synthesis and Antichlamydial Activity of Molecules Based on Dysregulators of Cylindrical Proteases. J Med Chem 2020; 63:4370-4387. [PMID: 32227948 DOI: 10.1021/acs.jmedchem.0c00371] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Chlamydia trachomatis is the most common sexually transmitted bacterial disease globally and the leading cause of infertility and preventable infectious blindness (trachoma) in the world. Unfortunately, there is no FDA-approved treatment specific for chlamydial infections. We recently reported two sulfonylpyridines that halt the growth of the pathogen. Herein, we present a SAR of the sulfonylpyridine molecule by introducing substituents on the aromatic regions. Biological evaluation studies showed that several analogues can impair the growth of C. trachomatis without affecting host cell viability. The compounds did not kill other bacteria, indicating selectivity for Chlamydia. The compounds presented mild toxicity toward mammalian cell lines. The compounds were found to be nonmutagenic in a Drosophila melanogaster assay and exhibited a promising stability in both plasma and gastric fluid. The presented results indicate this scaffold is a promising starting point for the development of selective antichlamydial drugs.
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Affiliation(s)
- Mohamed A Seleem
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Nathalia Rodrigues de Almeida
- Department of Chemistry, College of Arts and Sciences, University of Nebraska at Omaha, Omaha, Nebraska 68182, United States
| | - Yashpal Singh Chhonker
- Clinical Pharmacology Laboratory, Department of Pharmacy Practice and Science, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Daryl J Murry
- Clinical Pharmacology Laboratory, Department of Pharmacy Practice and Science, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Zaira da Rosa Guterres
- Laboratory of Cytogenetics and Mutagenesis, State University of Mato Grosso do Sul, Mundo Novo, Matto Grasso do Sul, Brazil
| | - Amanda M Blocker
- School of Biological Sciences, Southern Illinois University Carbondale, Carbondale, Illinois 62901, United States
| | - Shiomi Kuwabara
- School of Biological Sciences, Southern Illinois University Carbondale, Carbondale, Illinois 62901, United States
| | - Derek J Fisher
- School of Biological Sciences, Southern Illinois University Carbondale, Carbondale, Illinois 62901, United States
| | - Emilse S Leal
- Centro de Investigaciones en BioNanociencias (CIBION), Consejo Nacional de Investigaciones Cientı́ficas y Técnicas (CONICET), Godoy Cruz, 2390 Ciudad de Buenos Aires, Argentina
| | - Manuela R Martinefski
- Centro de Investigaciones en BioNanociencias (CIBION), Consejo Nacional de Investigaciones Cientı́ficas y Técnicas (CONICET), Godoy Cruz, 2390 Ciudad de Buenos Aires, Argentina
| | - Mariela Bollini
- Centro de Investigaciones en BioNanociencias (CIBION), Consejo Nacional de Investigaciones Cientı́ficas y Técnicas (CONICET), Godoy Cruz, 2390 Ciudad de Buenos Aires, Argentina
| | - María Eugenia Monge
- Centro de Investigaciones en BioNanociencias (CIBION), Consejo Nacional de Investigaciones Cientı́ficas y Técnicas (CONICET), Godoy Cruz, 2390 Ciudad de Buenos Aires, Argentina
| | - Scot P Ouellette
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Martin Conda-Sheridan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
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Nagpal J, Paxman JJ, Zammit JE, Thomas AA, Truscott KN, Heras B, Dougan DA. Molecular and structural insights into an asymmetric proteolytic complex (ClpP1P2) from Mycobacterium smegmatis. Sci Rep 2019; 9:18019. [PMID: 31792243 PMCID: PMC6889138 DOI: 10.1038/s41598-019-53736-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 10/25/2019] [Indexed: 11/09/2022] Open
Abstract
The ClpP protease is found in all kingdoms of life, from bacteria to humans. In general, this protease forms a homo-oligomeric complex composed of 14 identical subunits, which associates with its cognate ATPase in a symmetrical manner. Here we show that, in contrast to this general architecture, the Clp protease from Mycobacterium smegmatis (Msm) forms an asymmetric hetero-oligomeric complex ClpP1P2, which only associates with its cognate ATPase through the ClpP2 ring. Our structural and functional characterisation of this complex demonstrates that asymmetric docking of the ATPase component is controlled by both the composition of the ClpP1 hydrophobic pocket (Hp) and the presence of a unique C-terminal extension in ClpP1 that guards this Hp. Our structural analysis of MsmClpP1 also revealed openings in the side-walls of the inactive tetradecamer, which may represent sites for product egress.
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Affiliation(s)
- Jyotsna Nagpal
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Australia
| | - Jason J Paxman
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Australia
| | - Jessica E Zammit
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Australia
| | - Adam A. Thomas
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Australia
| | - Kaye N Truscott
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Australia
| | - Begoña Heras
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Australia.
| | - David A Dougan
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Australia.
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14
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The functional ClpXP protease of Chlamydia trachomatis requires distinct clpP genes from separate genetic loci. Sci Rep 2019; 9:14129. [PMID: 31575885 PMCID: PMC6773864 DOI: 10.1038/s41598-019-50505-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 09/13/2019] [Indexed: 12/15/2022] Open
Abstract
Clp proteases play a central role in bacterial physiology and, for some bacterial species, are even essential for survival. Also due to their conservation among bacteria including important human pathogens, Clp proteases have recently attracted considerable attention as antibiotic targets. Here, we functionally reconstituted and characterized the ClpXP protease of Chlamydia trachomatis (ctClpXP), an obligate intracellular pathogen and the causative agent of widespread sexually transmitted diseases in humans. Our in vitro data show that ctClpXP is formed by a hetero-tetradecameric proteolytic core, composed of two distinct homologs of ClpP (ctClpP1 and ctClpP2), that associates with the unfoldase ctClpX via ctClpP2 for regulated protein degradation. Antibiotics of the ADEP class interfere with protease functions by both preventing the interaction of ctClpX with ctClpP1P2 and activating the otherwise dormant proteolytic core for unregulated proteolysis. Thus, our results reveal molecular insight into ctClpXP function, validating this protease as an antibacterial target.
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15
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Felix J, Weinhäupl K, Chipot C, Dehez F, Hessel A, Gauto DF, Morlot C, Abian O, Gutsche I, Velazquez-Campoy A, Schanda P, Fraga H. Mechanism of the allosteric activation of the ClpP protease machinery by substrates and active-site inhibitors. SCIENCE ADVANCES 2019; 5:eaaw3818. [PMID: 31517045 PMCID: PMC6726451 DOI: 10.1126/sciadv.aaw3818] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 08/02/2019] [Indexed: 05/14/2023]
Abstract
Coordinated conformational transitions in oligomeric enzymatic complexes modulate function in response to substrates and play a crucial role in enzyme inhibition and activation. Caseinolytic protease (ClpP) is a tetradecameric complex, which has emerged as a drug target against multiple pathogenic bacteria. Activation of different ClpPs by inhibitors has been independently reported from drug development efforts, but no rationale for inhibitor-induced activation has been hitherto proposed. Using an integrated approach that includes x-ray crystallography, solid- and solution-state nuclear magnetic resonance, molecular dynamics simulations, and isothermal titration calorimetry, we show that the proteasome inhibitor bortezomib binds to the ClpP active-site serine, mimicking a peptide substrate, and induces a concerted allosteric activation of the complex. The bortezomib-activated conformation also exhibits a higher affinity for its cognate unfoldase ClpX. We propose a universal allosteric mechanism, where substrate binding to a single subunit locks ClpP into an active conformation optimized for chaperone association and protein processive degradation.
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Affiliation(s)
- Jan Felix
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des Martyrs, F-38044 Grenoble, France
| | - Katharina Weinhäupl
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des Martyrs, F-38044 Grenoble, France
| | - Christophe Chipot
- LPCT, UMR 7019 Université de Lorraine CNRS, Vandoeuvre-les-Nancy F-54500, France
- Laboratoire International Associé CNRS and University of Illinois at Urbana−Champaign, Vandoeuvre-les-Nancy F-54506, France
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL 61801, USA
| | - François Dehez
- LPCT, UMR 7019 Université de Lorraine CNRS, Vandoeuvre-les-Nancy F-54500, France
- Laboratoire International Associé CNRS and University of Illinois at Urbana−Champaign, Vandoeuvre-les-Nancy F-54506, France
| | - Audrey Hessel
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des Martyrs, F-38044 Grenoble, France
| | - Diego F. Gauto
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des Martyrs, F-38044 Grenoble, France
| | - Cecile Morlot
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des Martyrs, F-38044 Grenoble, France
| | - Olga Abian
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI and GBsC-CSIC-BIFI, and Department of Biochemistry and Molecular and Cell Biology, Universidad de Zaragoza, 50018 Zaragoza, Spain
- Aragon Institute for Health Research (IIS Aragon), 50009 Zaragoza, Spain
- Biomedical Research Networking Centre for Liver and Digestive Diseases (CIBERehd), Madrid, Spain
- Aragon Health Sciences Institute (IACS), 50009 Zaragoza, Spain
| | - Irina Gutsche
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des Martyrs, F-38044 Grenoble, France
| | - Adrian Velazquez-Campoy
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI and GBsC-CSIC-BIFI, and Department of Biochemistry and Molecular and Cell Biology, Universidad de Zaragoza, 50018 Zaragoza, Spain
- Aragon Institute for Health Research (IIS Aragon), 50009 Zaragoza, Spain
- Biomedical Research Networking Centre for Liver and Digestive Diseases (CIBERehd), Madrid, Spain
- Fundacion ARAID, Government of Aragon, 50018 Zaragoza, Spain
| | - Paul Schanda
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des Martyrs, F-38044 Grenoble, France
- Corresponding author. (H.F.); (P.S.)
| | - Hugo Fraga
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des Martyrs, F-38044 Grenoble, France
- Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Corresponding author. (H.F.); (P.S.)
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Dhara A, Hussain MS, Datta D, Kumar M. Insights to the Assembly of a Functionally Active Leptospiral ClpP1P2 Protease Complex along with Its ATPase Chaperone ClpX. ACS OMEGA 2019; 4:12880-12895. [PMID: 31460415 PMCID: PMC6682002 DOI: 10.1021/acsomega.9b00399] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 07/11/2019] [Indexed: 05/05/2023]
Abstract
Leptospira interrogans genome is predicted to encode multiple isoforms of caseinolytic proteases (ClpP1 and ClpP2). The ClpP proteins with the aid of its ATPase chaperone are known to be involved in establishing cellular proteostasis and have emerged as a target for developing new antibiotics. We report the molecular characterization of recombinant ClpP1 (rClpP1) and rClpP2 of Leptospira along with its ATPase chaperone rClpX. The two isoforms of rClpPs when coupled together in an equivalent concentration exhibit optimum activity on small fluorogenic peptide substrates, whereas the pure rClpP isoforms are enzymatically inactive. Isothermal titration calorimetry analysis suggests that the two rClpP isoforms bind each other moderately in a 1:1 stoichiometry with a dissociation constant of 2.02 ± 0.1 μM at 37 °C and is thermodynamically favored. Size exclusion chromatography fractionates the majority of pure rClpP1 at ≥308 kDa (14-21-mer) and the pure rClpP2 at 308 kDa (tetradecamer), whereas the functionally active rClpP isoform mixture fractionates as a tetradecamer. The distinct and unprecedented oligomeric form of rClpP1 was also evident through native-gel and dynamic light scattering. Moreover, the rClpP isoform mixture formed after the site-directed mutation of either or both the isoforms at one of the catalytic triad residues (Ser 98/97 to Ala 98/97) resulted in the complete loss of protease activity. The rClpP isoform mixture gets stimulated to degrade the casein substrate in the presence of rClpX and in an energy-dependent manner. On the contrary, pure rClpP1 or the rClpP2 isoform in association with rClpX are incapable of forming operative protease. The reported finding suggests that in Leptospira, the enzymatic activity of the rClpP protease complex in the presence or absence of cochaperone is performed solely by the tetradecamer structure which is hypothesized to be composed of 2-stacked ClpP heptameric rings, wherein each ring is a homo-oligomer of ClpP1 and ClpP2 subunits. Understanding the activities and regulation principle of multi-isoforms of ClpP in pathogenic bacteria may aid in intervening disease outcomes particularly to the co-evolving antibiotic resistance strains.
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Affiliation(s)
| | | | | | - Manish Kumar
- E-mail: . Phone: +91-361-258-2230. Fax: +91-361-258-2249
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