1
|
Sciacca C, Cardullo N, Pulvirenti L, Travagliante G, D'Urso A, D'Agata R, Peri E, Cancemi P, Cornu A, Deffieux D, Pouységu L, Quideau S, Muccilli V. Synthesis of obovatol and related neolignan analogues as α-glucosidase and α-amylase inhibitors. Bioorg Chem 2024; 147:107392. [PMID: 38723423 DOI: 10.1016/j.bioorg.2024.107392] [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: 12/08/2023] [Revised: 04/12/2024] [Accepted: 04/21/2024] [Indexed: 05/18/2024]
Abstract
Diabetes mellitus is a metabolic disease characterized by hyperglycemia, which can be counteracted by the inhibition of α-glucosidase (α-Glu) and α-amylase (α-Amy), enzymes responsible for the hydrolysis of carbohydrates. In recent decades, many natural compounds and their bioinspired analogues have been studied as α-Glu and α-Amy inhibitors. However, no studies have been devoted to the evaluation of α-Glu and α-Amy inhibition by the neolignan obovatol (1). In this work, we report the synthesis of 1 and a library of new analogues. The synthesis of these compounds was achieved by implementing methodologies based on: phenol allylation, Claisen/Cope rearrangements, methylation, Ullmann coupling, demethylation, phenol oxidation and Michael-type addition. Obovatol (1) and ten analogues were evaluated for their in vitro inhibitory activity towards α-Glu and α-Amy. Our investigation highlighted that the naturally occurring 1 and four neolignan analogues (11, 22, 26 and 27) were more effective inhibitors than the hypoglycemic drug acarbose (α-Amy: 34.6 µM; α-Glu: 248.3 µM) with IC5O value of 6.2-23.6 µM toward α-Amy and 39.8-124.6 µM toward α-Glu. Docking investigations validated the inhibition outcomes, highlighting optimal compatibility between synthesized neolignans and both the enzymes. Concurrently circular dichroism spectroscopy detected the conformational changes in α-Glu induced by its interaction with the studied neolignans. Detailed studies through fluorescence measurements and kinetics of α-Glu and α-Amy inhibition also indicated that 1, 11, 22, 26 and 27 have the greatest affinity for α-Glu and 1, 11 and 27 for α-Amy. Surface plasmon resonance imaging (SPRI) measurements confirmed that among the compounds studied, the neolignan 27 has the greater affinity for both enzymes, thus corroborating the results obtained by kinetics and fluorescence quenching. Finally, in vitro cytotoxicity of the investigated compounds was tested on human colon cancer cell line (HCT-116). All these results demonstrate that these obovatol-based neolignan analogues constitute promising candidates in the pursuit of developing novel hypoglycemic drugs.
Collapse
Affiliation(s)
- Claudia Sciacca
- Department of Chemical Sciences, University of Catania, V.le A. Doria 6, 95125 Catania, Italy
| | - Nunzio Cardullo
- Department of Chemical Sciences, University of Catania, V.le A. Doria 6, 95125 Catania, Italy
| | - Luana Pulvirenti
- CNR-ICB, Consiglio Nazionale delle Ricerche-Istituto di Chimica Biomolecolare, via Paolo Gaifami 18, Catania 95126, Italy
| | - Gabriele Travagliante
- Department of Chemical Sciences, University of Catania, V.le A. Doria 6, 95125 Catania, Italy
| | - Alessandro D'Urso
- Department of Chemical Sciences, University of Catania, V.le A. Doria 6, 95125 Catania, Italy
| | - Roberta D'Agata
- Department of Chemical Sciences, University of Catania, V.le A. Doria 6, 95125 Catania, Italy
| | - Emanuela Peri
- Department of Biological Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, Palermo 90128, Italy
| | - Patrizia Cancemi
- Department of Biological Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, Palermo 90128, Italy
| | - Anaëlle Cornu
- Univ. Bordeaux, ISM (CNRS-UMR 5255), 351 cours de la Libération, Talence Cedex, France
| | - Denis Deffieux
- Univ. Bordeaux, ISM (CNRS-UMR 5255), 351 cours de la Libération, Talence Cedex, France
| | - Laurent Pouységu
- Univ. Bordeaux, ISM (CNRS-UMR 5255), 351 cours de la Libération, Talence Cedex, France
| | - Stéphane Quideau
- Univ. Bordeaux, ISM (CNRS-UMR 5255), 351 cours de la Libération, Talence Cedex, France; Institut Universitaire de France, 1 rue Descartes, 75231 Paris Cedex 05, France.
| | - Vera Muccilli
- Department of Chemical Sciences, University of Catania, V.le A. Doria 6, 95125 Catania, Italy.
| |
Collapse
|
2
|
Blasey N, Rehrmann D, Riebisch AK, Mühlen S. Targeting bacterial pathogenesis by inhibiting virulence-associated Type III and Type IV secretion systems. Front Cell Infect Microbiol 2023; 12:1065561. [PMID: 36704108 PMCID: PMC9872159 DOI: 10.3389/fcimb.2022.1065561] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Accepted: 12/19/2022] [Indexed: 01/12/2023] Open
Abstract
Infections caused by Gram-negative pathogens pose a major health burden. Both respiratory and gastrointestinal infections are commonly associated with these pathogens. With the increase in antimicrobial resistance (AMR) over the last decades, bacterial infections may soon become the threat they have been before the discovery of antibiotics. Many Gram-negative pathogens encode virulence-associated Type III and Type IV secretion systems, which they use to inject bacterial effector proteins across bacterial and host cell membranes into the host cell cytosol, where they subvert host cell functions in favor of bacterial replication and survival. These secretion systems are essential for the pathogens to cause disease, and secretion system mutants are commonly avirulent in infection models. Hence, these structures present attractive targets for anti-virulence therapies. Here, we review previously and recently identified inhibitors of virulence-associated bacterial secretions systems and discuss their potential as therapeutics.
Collapse
|
3
|
Qian H, Song L, Wang L, Wang B, Liang W. The secreted FoAPY1 peptidase promotes Fusarium oxysporum invasion. Front Microbiol 2022; 13:1040302. [PMID: 36338032 PMCID: PMC9626516 DOI: 10.3389/fmicb.2022.1040302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 10/06/2022] [Indexed: 11/18/2022] Open
Abstract
The secretion of peptidases from several pathogens has been reported, but the biological function of these proteins in plant-pathogen interactions is poorly understood. Fusarium oxysporum, a soil-borne plant pathogenic fungus that causes Fusarium wilt in its host, can secrete proteins into host plant cells during the infection process to interfere with the host plant defense response and promote disease occurrence. In this study, we identified a peptidase, FoAPY1, that could be secreted from F. oxysporum depending on the N-terminal signal peptide of the protein. FoAPY1 belongs to the peptidase M28 family and exerts peptidase activity in vitro. Furthermore, the FoAYP1 gene knockout strain (∆FoAYP1) presented reduced virulence to tomato plants, but its mycelial growth and conidiation were unchanged. Moreover, FoAYP1 overexpression tomato seedlings exhibited enhanced susceptibility to F. oxysporum and Botrytis cinerea strains. These data demonstrated that FoAYP1 contributes to the virulence of F. oxysporum may through peptidase activity against host plant proteins.
Collapse
Affiliation(s)
- Hengwei Qian
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Limin Song
- Key Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - Lulu Wang
- Key Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - Baoshan Wang
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Wenxing Liang
- Key Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
- *Correspondence: Wenxing Liang,
| |
Collapse
|
4
|
Qian H, Wang L, Wang B, Liang W. The secreted ribonuclease T2 protein FoRnt2 contributes to Fusarium oxysporum virulence. MOLECULAR PLANT PATHOLOGY 2022; 23:1346-1360. [PMID: 35696123 PMCID: PMC9366063 DOI: 10.1111/mpp.13237] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/28/2022] [Accepted: 05/24/2022] [Indexed: 05/03/2023]
Abstract
Secreted RNase proteins have been reported from only a few pathogens, and relatively little is known about their biological functions. Fusarium oxysporum is a soilborne fungal pathogen that causes Fusarium wilt, one of the most important diseases on tomato. During the infection of F. oxysporum, some proteins are secreted that modulate host plant immunity and promote pathogen invasion. In this study, we identify an RNase, FoRnt2, from the F. oxysporum secretome that belongs to the ribonuclease T2 family. FoRnt2 possesses an N-terminal signal peptide and can be secreted from F. oxysporum. FoRnt2 exhibited ribonuclease activity and was able to degrade the host plant total RNA in vitro dependent on the active site residues H80 and H142. Deletion of the FoRnt2 gene reduced fungal virulence but had no obvious effect on mycelial growth and conidial production. The expression of FoRnt2 in tomato significantly enhanced plant susceptibility to pathogens. These data indicate that FoRnt2 is an important contributor to the virulence of F. oxysporum, possibly through the degradation of plant RNA.
Collapse
Affiliation(s)
- Hengwei Qian
- College of Life SciencesShandong Normal UniversityJinanChina
| | - Lulu Wang
- Key Lab of Integrated Crop Pest Management of Shandong ProvinceCollege of Plant Health and Medicine, Qingdao Agricultural UniversityQingdaoChina
| | - Baoshan Wang
- College of Life SciencesShandong Normal UniversityJinanChina
| | - Wenxing Liang
- Key Lab of Integrated Crop Pest Management of Shandong ProvinceCollege of Plant Health and Medicine, Qingdao Agricultural UniversityQingdaoChina
| |
Collapse
|
5
|
Developing Cyclic Peptomers as Broad-Spectrum Type III Secretion System Inhibitors in Gram-Negative Bacteria. Antimicrob Agents Chemother 2021; 65:e0169020. [PMID: 33875435 PMCID: PMC8373237 DOI: 10.1128/aac.01690-20] [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] [Indexed: 12/15/2022] Open
Abstract
Antibiotic-resistant bacteria are an emerging global health threat. New antimicrobials are urgently needed. The injectisome type III secretion system (T3SS), required by dozens of Gram-negative bacteria for virulence but largely absent from nonpathogenic bacteria, is an attractive antimicrobial target. We previously identified synthetic cyclic peptomers, inspired by the natural product phepropeptin D, that inhibit protein secretion through the Yersinia Ysc and Pseudomonas aeruginosa Psc T3SSs but do not inhibit bacterial growth. Here, we describe the identification of an isomer, 4EpDN, that is 2-fold more potent (50% inhibitory concentration [IC50] of 4 μM) than its parental compound. Furthermore, 4EpDN inhibited the Yersinia Ysa and the Salmonella SPI-1 T3SSs, suggesting that this cyclic peptomer has broad efficacy against evolutionarily distant injectisome T3SSs. Indeed, 4EpDN strongly inhibited intracellular growth of Chlamydia trachomatis in HeLa cells, which requires the T3SS. 4EpDN did not inhibit the unrelated twin arginine translocation (Tat) system, nor did it impact T3SS gene transcription. Moreover, although the injectisome and flagellar T3SSs are evolutionarily and structurally related, the 4EpDN cyclic peptomer did not inhibit secretion of substrates through the Salmonella flagellar T3SS, indicating that cyclic peptomers broadly but specifically target the injectisome T3SS. 4EpDN reduced the number of T3SS needles detected on the surface of Yersinia pseudotuberculosis as detected by microscopy. Collectively, these data suggest that cyclic peptomers specifically inhibit the injectisome T3SS from a variety of Gram-negative bacteria, possibly by preventing complete T3SS assembly.
Collapse
|
6
|
Bagherniya M, Khedmatgozar H, Fakheran O, Xu S, Johnston TP, Sahebkar A. Medicinal plants and bioactive natural products as inhibitors of NLRP3 inflammasome. Phytother Res 2021; 35:4804-4833. [PMID: 33856730 DOI: 10.1002/ptr.7118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 02/02/2021] [Accepted: 03/26/2021] [Indexed: 12/11/2022]
Abstract
The NLR family, pyrin domain-containing 3 (NLRP3) inflammasome is a multiprotein complex that induces caspase-1 activation and the downstream substrates involved with the processing and secretion of the pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18 and tumor necrosis factor-α (TNF- α). The NLRP3 inflammasome is activated by a wide range of danger signals that derive from metabolic dysregulation. Activation of this complex often involves the adaptor ASC and upstream sensors including NLRP1, NLRP3, NLRC4, AIM2, and pyrin, which are activated by different stimuli including infectious agents and changes in cell homeostasis. It has been shown that nutraceuticals and medicinal plants have antiinflammatory properties and could be used as complementary therapy in the treatment of several chronic diseases that are related to inflammation, for example, cardiovascular diseases and diabetes mellitus. Herb-based medicine has demonstrated protective effects against NLRP3 inflammasome activation. Therefore, this review focuses on the effects of nutraceuticals and bioactive compounds derived from medicinal plants on NLRP3 inflammasome activation and the possible mechanisms of action of these natural products. Thus, herb-based, natural products/compounds can be considered novel, practical, and accessible agents in chronic inflammatory diseases by inhibiting NLRP3 inflammasome activation.
Collapse
Affiliation(s)
- Mohammad Bagherniya
- Food Security Research Center, Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran.,Anesthesia and Critical Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Hamed Khedmatgozar
- Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Omid Fakheran
- Dental Research Center, Department of Periodontics, Dental Research Institute, Isfahan University of Medical sciences, Isfahan, Iran
| | - Suowen Xu
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Thomas P Johnston
- Division of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.,Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Polish Mother's Memorial Hospital Research Institute (PMMHRI), Lodz, Poland.,School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| |
Collapse
|
7
|
Design of Non-Haemolytic Nanoemulsions for Intravenous Administration of Hydrophobic APIs. Pharmaceutics 2020; 12:pharmaceutics12121141. [PMID: 33255606 PMCID: PMC7760703 DOI: 10.3390/pharmaceutics12121141] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/06/2020] [Accepted: 11/19/2020] [Indexed: 02/07/2023] Open
Abstract
Among advanced formulation strategies, nanoemulsions are considered useful drug-delivery systems allowing to improve the solubility and the bioavailability of lipophilic drugs. To select safe excipients for nanoemulsion formulation and to discard any haemolytic potential, an in vitro miniaturized test was performed on human whole blood. From haemolysis results obtained on eighteen of the most commonly used excipients, a medium chain triglyceride, a surfactant, and a solubilizer were selected for formulation assays. Based on a design of experiments and a ternary diagram, the feasibility of nanoemulsions was determined. The composition was defined to produce monodisperse nanodroplets with a diameter of either 50 or 120 nm, and their physicochemical properties were optimized to be suitable for intravenous administration. These nanoemulsions, stable over 21 days in storage conditions, were shown to be able to encapsulate with high encapsulation efficiency and high drug loading, up to 16% (w/w), two water practically insoluble drug models: ibuprofen and fenofibrate. Both drugs may be released according to a modulable profile in sink conditions. Such nanoemulsions appear as a very promising and attractive strategy for the efficient early preclinical development of hydrophobic drugs.
Collapse
|
8
|
Kongkham B, Prabakaran D, Puttaswamy H. Opportunities and challenges in managing antibiotic resistance in bacteria using plant secondary metabolites. Fitoterapia 2020; 147:104762. [PMID: 33069839 DOI: 10.1016/j.fitote.2020.104762] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 10/08/2020] [Accepted: 10/12/2020] [Indexed: 12/11/2022]
Abstract
Development of antibiotic resistance (ABR) in bacteria and its multidimensional spread is an emerging global threat that needs immediate attention. Extensive antibiotics (AB) usage results in development of ABR in bacteria by target modification, production of AB degrading enzymes, porin modifications, efflux pumps overexpression, etc. To counter this, apart from strict regulation of AB use and behavioural changes, research and development (R&D) of newer antimicrobials are in place. One such emerging approach to combat ABR is the use of structurally and functionally diverse plant secondary metabolites (PSMs) in combination with the conventional AB. Either the PSMs are themselves antimicrobial or they potentiate the activity of the AB through a range of mechanisms. However, their use is lagging due to poor knowledge of mode of action, structure-activity relationships, pharmacokinetics, etc. This review paper discussed the opportunities and challenges in managing ABR using PSMs. Mechanisms of ABR development in bacteria and current strategies to counter them were studied and the areas where PSMs can play an important role were highlighted. The use of PSMs, both as an anti-resistance and anti-virulence agent in combination therapy to counter multi-drug resistance along with their mechanisms of action, has been discussed in detail. The difficulties in the commercialisation of PSMs and strategies to overcome them along with future priority areas of research have also been given. Following the given R&D path will definitely help in better understanding and utilising the full potential of PSMs in solving the problem of antimicrobial resistance (AMR).
Collapse
Affiliation(s)
- Bhani Kongkham
- Environmental Biotechnology Laboratory, Centre for Rural Development and Technology, Indian Institute of Technology Delhi, Delhi 110016, India
| | - Duraivadivel Prabakaran
- Environmental Biotechnology Laboratory, Centre for Rural Development and Technology, Indian Institute of Technology Delhi, Delhi 110016, India
| | - Hariprasad Puttaswamy
- Environmental Biotechnology Laboratory, Centre for Rural Development and Technology, Indian Institute of Technology Delhi, Delhi 110016, India.
| |
Collapse
|
9
|
Kim J, Ahn H, Han BC, Shin H, Kim JC, Jung EM, Kim J, Yang H, Lee J, Kang SG, Lee SH, Lee GS. Obovatol inhibits NLRP3, AIM2, and non-canonical inflammasome activation. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2019; 63:153019. [PMID: 31302317 DOI: 10.1016/j.phymed.2019.153019] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 07/01/2019] [Accepted: 07/04/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Obovatol, a biphenolic chemical originating from Magnolia obovata, has been utilized as a traditional medicine for the treatment of inflammatory diseases. Inflammasome induces maturation of inflammatory cytokines in response to intracellular danger signals, and its dysregulation induces inflammatory diseases. PURPOSE The effect of obovatol on inflammasome activation has not been reported, although its anti-inflammatory properties have been studied. STUDY DESIGN/METHODS Obovatol was treated to macrophages with inflammasome triggers, and secretions of interleukin (IL)-1β, IL-18, and caspase-1 were measured as readouts of inflammasome activation. In addition, Asc pyroptosome formation, caspase-1 activity, and mitochondrial reactive oxygen species (ROS) production were analyzed in mechanical studies. Anti-inflammasome properties of obovatol were confirmed in an animal model. RESULTS Obovatol inhibited NLRP3, AIM2, and non-canonical inflammasomes through inhibition of Asc pyroptosome formation and mitochondrial ROS generation. In addition, obovatol disrupted the priming step of inflammasome activation and inhibited transcription of inflammatory cytokines. In mice, obovatol attenuated serum IL-1β elevation in response to monosodium urate crystals. CONCLUSION Obovatol is suggested as an inhibitor of NLRP3, AIM2, and non-canonical inflammasomes.
Collapse
Affiliation(s)
- Jeongeun Kim
- College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon, Gangwon, 24341, Republic of Korea
| | - Huijeong Ahn
- College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon, Gangwon, 24341, Republic of Korea
| | - Byung-Cheol Han
- College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon, Gangwon, 24341, Republic of Korea; Korea Ginseng Research Institute, Korea Ginseng Corporation, Daejeon, 34337, Republic of Korea
| | - Hyunjung Shin
- Korea Ginseng Research Institute, Korea Ginseng Corporation, Daejeon, 34337, Republic of Korea
| | - Jin-Chul Kim
- Natural Products Research Center, Korea Institute of Science and Technology, Gangneung, 25451, Republic of Korea
| | - Eui-Man Jung
- Laboratory of Veterinary Biochemistry and Molecular Biology College of Veterinary Medicine, Chungbuk National University, Cheongju, 28644, Republic of Korea
| | - Juyeol Kim
- College of Pharmacy, Kangwon National University, Chuncheon, Gangwon, 24341, Republic of Korea
| | - Heejung Yang
- College of Pharmacy, Kangwon National University, Chuncheon, Gangwon, 24341, Republic of Korea
| | - Jeonghyun Lee
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Seung Goo Kang
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Seung-Ho Lee
- Korea Ginseng Research Institute, Korea Ginseng Corporation, Daejeon, 34337, Republic of Korea
| | - Geun-Shik Lee
- College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon, Gangwon, 24341, Republic of Korea.
| |
Collapse
|
10
|
Abstract
Antibiotic resistance is a major public health threat that has stimulated the scientific community to search for nontraditional therapeutic targets. Because virulence, but not the growth, of many Gram-negative bacterial pathogens depends on the multicomponent type three secretion system injectisome (T3SSi), the T3SSi has been an attractive target for identifying small molecules, peptides, and monoclonal antibodies that inhibit its function to render the pathogen avirulent. While many small-molecule lead compounds have been identified in whole-cell-based high-throughput screens (HTSs), only a few protein targets of these compounds are known; such knowledge is an important step to developing more potent and specific inhibitors. Evaluation of the efficacy of compounds in animal studies is ongoing. Some efforts involving the development of antibodies and vaccines that target the T3SSi are further along and include an antibody that is currently in phase II clinical trials. Continued research into these antivirulence therapies, used alone or in combination with traditional antibiotics, requires combined efforts from both pharmaceutical companies and academic labs.
Collapse
|