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Dombach JL, Christensen GL, Allgood SC, Quintana JLJ, Detweiler CS. Inhibition of multiple staphylococcal growth states by a small molecule that disrupts membrane fluidity and voltage. mSphere 2024; 9:e0077223. [PMID: 38445864 PMCID: PMC10964410 DOI: 10.1128/msphere.00772-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 01/26/2024] [Indexed: 03/07/2024] Open
Abstract
New molecular approaches to disrupting bacterial infections are needed. The bacterial cell membrane is an essential structure with diverse potential lipid and protein targets for antimicrobials. While rapid lysis of the bacterial cell membrane kills bacteria, lytic compounds are generally toxic to whole animals. In contrast, compounds that subtly damage the bacterial cell membrane could disable a microbe, facilitating pathogen clearance by the immune system with limited compound toxicity. A previously described small molecule, D66, terminates Salmonella enterica serotype Typhimurium (S. Typhimurium) infection of macrophages and reduces tissue colonization in mice. The compound dissipates bacterial inner membrane voltage without rapid cell lysis under broth conditions that permeabilize the outer membrane or disable efflux pumps. In standard media, the cell envelope protects Gram-negative bacteria from D66. We evaluated the activity of D66 in Gram-positive bacteria because their distinct envelope structure, specifically the absence of an outer membrane, could facilitate mechanism of action studies. We observed that D66 inhibited Gram-positive bacterial cell growth, rapidly increased Staphylococcus aureus membrane fluidity, and disrupted membrane voltage while barrier function remained intact. The compound also prevented planktonic staphylococcus from forming biofilms and a disturbed three-dimensional structure in 1-day-old biofilms. D66 furthermore reduced the survival of staphylococcal persister cells and of intracellular S. aureus. These data indicate that staphylococcal cells in multiple growth states germane to infection are susceptible to changes in lipid packing and membrane conductivity. Thus, agents that subtly damage bacterial cell membranes could have utility in preventing or treating disease.IMPORTANCEAn underutilized potential antibacterial target is the cell membrane, which supports or associates with approximately half of bacterial proteins and has a phospholipid makeup distinct from mammalian cell membranes. Previously, an experimental small molecule, D66, was shown to subtly damage Gram-negative bacterial cell membranes and to disrupt infection of mammalian cells. Here, we show that D66 increases the fluidity of Gram-positive bacterial cell membranes, dissipates membrane voltage, and inhibits the human pathogen Staphylococcus aureus in several infection-relevant growth states. Thus, compounds that cause membrane damage without lysing cells could be useful for mitigating infections caused by S. aureus.
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Affiliation(s)
- Jamie L. Dombach
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Grace L. Christensen
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Samual C. Allgood
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Joaquin L. J. Quintana
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Corrella S. Detweiler
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
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Allgood SC, Su CC, Crooks AL, Meyer CT, Zhou B, Betterton MD, Barbachyn MR, Yu EW, Detweiler CS. Bacterial efflux pump modulators prevent bacterial growth in macrophages and under broth conditions that mimic the host environment. mBio 2023; 14:e0249223. [PMID: 37921493 PMCID: PMC10746280 DOI: 10.1128/mbio.02492-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 09/21/2023] [Indexed: 11/04/2023] Open
Abstract
IMPORTANCE Bacterial efflux pumps are critical for resistance to antibiotics and for virulence. We previously identified small molecules that inhibit efflux pumps (efflux pump modulators, EPMs) and prevent pathogen replication in host cells. Here, we used medicinal chemistry to increase the activity of the EPMs against pathogens in cells into the nanomolar range. We show by cryo-electron microscopy that these EPMs bind an efflux pump subunit. In broth culture, the EPMs increase the potency (activity), but not the efficacy (maximum effect), of antibiotics. We also found that bacterial exposure to the EPMs appear to enable the accumulation of a toxic metabolite that would otherwise be exported by efflux pumps. Thus, inhibitors of bacterial efflux pumps could interfere with infection not only by potentiating antibiotics, but also by allowing toxic waste products to accumulate within bacteria, providing an explanation for why efflux pumps are needed for virulence in the absence of antibiotics.
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Affiliation(s)
- Samual C. Allgood
- Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Chih-Chia Su
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Amy L. Crooks
- Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Christian T. Meyer
- Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
- Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado, USA
- Duet Biosystems, Nashville, Tennessee, USA
- Antimicrobial Research Consortium (ARC) Labs, Boulder, Colorado, USA
| | - Bojun Zhou
- Department of Physics, University of Colorado, Boulder, Colorado, USA
| | - Meredith D. Betterton
- Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
- Department of Physics, University of Colorado, Boulder, Colorado, USA
- Center for Computational Biology, Flatiron Institute, New York, New York, USA
| | | | - Edward W. Yu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Corrella S. Detweiler
- Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
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Li Y, Li W, Zeng Z, Han Y, Chen Q, Dong X, Wang Z, Feng S, Cao W. Lasso peptide MccY alleviates non-typhoidal salmonellae-induced mouse gut inflammation via regulation of intestinal barrier function and gut microbiota. Microbiol Spectr 2023; 11:e0178423. [PMID: 37819128 PMCID: PMC10714986 DOI: 10.1128/spectrum.01784-23] [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: 05/05/2023] [Accepted: 08/28/2023] [Indexed: 10/13/2023] Open
Abstract
IMPORTANCE Diseases caused by Enterobacteriaceae multidrug-resistant strains have become increasingly difficult to manage. It is necessary to verify the new antibacterial drug MccY effect on non-typhoid Salmonella infection in mice since it is regarded as a promising microcin. The results demonstrated that MccY has a potential therapeutic application value in the protection against Salmonella-induced intestinal damage and alleviating related intestinal dysbiosis and metabolic disorders. MccY could be a promising candidate as an antimicrobial or anti-inflammatory agent for treating infectious diseases.
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Affiliation(s)
- Yu Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Wenjing Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Zhiwei Zeng
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Yu Han
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Qinxi Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Xinyi Dong
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Zepeng Wang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Saixiang Feng
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangdong, China
- Key Laboratory of Zoonosis of Ministry of Agriculture and Rural Affairs, Guangzhou, China
- Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture and Rural Affairs, Guangzhou, China
- National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control, Guangzhou, China
| | - Weisheng Cao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangdong, China
- Key Laboratory of Zoonosis of Ministry of Agriculture and Rural Affairs, Guangzhou, China
- Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture and Rural Affairs, Guangzhou, China
- National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control, Guangzhou, China
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Allgood SC, Su CC, Crooks AL, Meyer CT, Zhou B, Betterton MD, Barbachyn MR, Yu EW, Detweiler CS. Bacterial Efflux Pump Modulators Prevent Bacterial Growth in Macrophages and Under Broth Conditions that Mimic the Host Environment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.20.558466. [PMID: 37786697 PMCID: PMC10541609 DOI: 10.1101/2023.09.20.558466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
New approaches for combatting microbial infections are needed. One strategy for disrupting pathogenesis involves developing compounds that interfere with bacterial virulence. A critical molecular determinant of virulence for Gram-negative bacteria are efflux pumps of the resistance-nodulation-division (RND) family, which includes AcrAB-TolC. We previously identified small molecules that bind AcrB, inhibit AcrAB-TolC, and do not appear to damage membranes. These efflux pump modulators (EPMs) were discovered in an in-cell screening platform called SAFIRE (Screen for Anti-infectives using Fluorescence microscopy of IntracellulaR Enterobacteriaceae). SAFIRE identifies compounds that disrupt the growth of a Gram-negative human pathogen, Salmonella enterica serotype Typhimurium (S. Typhimurium) in macrophages. We used medicinal chemistry to iteratively design ~200 EPM35 analogs and test them for activity in SAFIRE, generating compounds with nanomolar potency. Analogs were demonstrated to bind AcrB in a substrate binding pocket by cryo-electron microscopy (cryo-EM). Despite having amphipathic structures, the EPM analogs do not disrupt membrane voltage, as monitored by FtsZ localization to the cell septum. The EPM analogs had little effect on bacterial growth in standard Mueller Hinton Broth. However, under broth conditions that mimic the micro-environment of the macrophage phagosome, acrAB is required for growth, the EPM analogs are bacteriostatic, and increase the potency of antibiotics. These data suggest that under macrophage-like conditions the EPM analogs prevent the export of a toxic bacterial metabolite(s) through AcrAB-TolC. Thus, compounds that bind AcrB could disrupt infection by specifically interfering with the export of bacterial toxic metabolites, host defense factors, and/or antibiotics.
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Affiliation(s)
- Samual C Allgood
- Molecular, Cellular Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Chih-Chia Su
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Amy L Crooks
- Molecular, Cellular Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Christian T Meyer
- Molecular, Cellular Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
- Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, USA
- Duet Biosystems, Nashville, TN, USA
- Antimicrobial Research Consortium (ARC) Labs, Boulder, CO, USA
| | - Bojun Zhou
- Department of Physics, University of Colorado, Boulder, CO, USA
| | - Meredith D Betterton
- Molecular, Cellular Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
- Department of Physics, University of Colorado, Boulder, CO, USA
- Center for Computational Biology, Flatiron Institute, New York, NY, USA
| | | | - Edward W Yu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Corrella S Detweiler
- Molecular, Cellular Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
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He Y, Wang J, Zhang R, Chen L, Zhang H, Qi X, Chen J. Epidemiology of foodborne diseases caused by Salmonella in Zhejiang Province, China, between 2010 and 2021. Front Public Health 2023; 11:1127925. [PMID: 36817893 PMCID: PMC9929456 DOI: 10.3389/fpubh.2023.1127925] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 01/17/2023] [Indexed: 02/04/2023] Open
Abstract
Objective Salmonella infection is a common cause of bacterial foodborne diseases (FBDs) globally. In this study, we aimed to explore the epidemiological and etiological characteristics of Salmonella infection from 2012-2021 in Zhejiang Province, China. Methods Descriptive statistical methods were used to analyze the data reported by the Centers for Disease Control and Prevention at all levels in Zhejiang Province through the China National Foodborne Diseases Surveillance Network from 2012-2021. Results A total of 11,269 Salmonella cases were reported, with an average positive rate of 3.65%, including 1,614 hospitalizations. A significant seasonal trend was observed for Salmonella cases, with the highest rate over the summer period, peaking from May to October, accounting for 77.96%. The results indicated a higher positive rate among respondents aged 0-4 years, especially for the scattered children (P < 0.05). The highest number of Salmonella infections were caused due to contaminated fruit and fruit products. Households (54.69%) had the most common exposure settings. Serotypes analysis revealed that Salmonella typhimurium (36.07%), Salmonella enteritidis (15.17%), and Salmonella london (6.05%) were the dominant strains among the 173 serotypes. Diarrhea, abdominal pain, fever, nausea, and vomiting were the main symptoms of these serotypes. Conclusions FBDs caused by Salmonella are important issues for public health in Zhejiang Province, and there is a need to focus on the epidemiological and etiological characteristics to control Salmonella infections.
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Affiliation(s)
| | | | - Ronghua Zhang
- Department of Nutrition and Food Safety, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
| | - Lili Chen
- Department of Nutrition and Food Safety, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
| | - Hexiang Zhang
- Department of Nutrition and Food Safety, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
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Wang C, Yang Y, Cao Y, Liu K, Shi H, Guo X, Liu W, Hao R, Song H, Zhao R. Nanocarriers for the delivery of antibiotics into cells against intracellular bacterial infection. Biomater Sci 2023; 11:432-444. [PMID: 36503914 DOI: 10.1039/d2bm01489k] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The barrier function of host cells enables intracellular bacteria to evade the lethality of the host immune system and antibiotics, thereby causing chronic and recurrent infections that seriously threaten human health. Currently, the main clinical strategy for the treatment of intracellular bacterial infections involves the use of long-term and high-dose antibiotics. However, insufficient intracellular delivery of antibiotics along with various resistance mechanisms not only weakens the efficacy of current therapies but also causes serious adverse drug reactions, further increasing the disease and economic burden. Improving the delivery efficiency, intracellular accumulation, and action time of antibiotics remains the most economical and effective way to treat intracellular bacterial infections. The rapid development of nanotechnology provides a strategy to efficiently deliver antibiotics against intracellular bacterial infections into cells. In this review, we summarize the types of common intracellular pathogens, the difficulties faced by antibiotics in the treatment of intracellular bacterial infections, and the research progress of several types of representative nanocarriers for the delivery of antibiotics against intracellular bacterial infections that have emerged in recent years. This review is expected to provide a reference for further elucidating the intracellular transport mechanism of nanocarrier-drug complexes, designing safer and more effective nanocarriers and establishing new strategies against intracellular bacterial infection.
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Affiliation(s)
- Chao Wang
- Chinese PLA Center for Disease Control and Prevention, Beijing, 100071, China.
| | - Yi Yang
- Chinese PLA Center for Disease Control and Prevention, Beijing, 100071, China.
| | - Yuanyuan Cao
- Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, Beijing, 100069, China.
| | - Kaixin Liu
- Chinese PLA Center for Disease Control and Prevention, Beijing, 100071, China.
| | - Hua Shi
- Chinese PLA Center for Disease Control and Prevention, Beijing, 100071, China.
| | - Xudong Guo
- Chinese PLA Center for Disease Control and Prevention, Beijing, 100071, China.
| | - Wanying Liu
- Chinese PLA Center for Disease Control and Prevention, Beijing, 100071, China.
| | - Rongzhang Hao
- Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, Beijing, 100069, China.
| | - Hongbin Song
- Chinese PLA Center for Disease Control and Prevention, Beijing, 100071, China.
| | - Rongtao Zhao
- Chinese PLA Center for Disease Control and Prevention, Beijing, 100071, China.
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7
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Wiradiputra MRD, Khuntayaporn P, Thirapanmethee K, Chomnawang MT. Toxin-Antitoxin Systems: A Key Role on Persister Formation in Salmonella enterica Serovar Typhimurium. Infect Drug Resist 2022; 15:5813-5829. [PMID: 36213766 PMCID: PMC9541301 DOI: 10.2147/idr.s378157] [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] [Received: 06/11/2022] [Accepted: 09/16/2022] [Indexed: 11/05/2022] Open
Abstract
The toxin and antitoxin modules in bacteria consist of a toxin molecule that has activity to inhibit various cellular processes and its cognate antitoxin that neutralizes the toxin. This system is considered taking part in the formation of persister cells, which are a subpopulation of recalcitrant cells able to survive antimicrobial treatment without any resistance mechanisms. Importantly, persisters have been associated with long-term infections and treatment failures in healthcare settings. It is a public health concern since persisters can be involved in the evolution and dissemination of antimicrobial resistance amidst the aggravating spread of multidrug-resistant bacteria and insufficient novel antimicrobial therapy to tackle this issue. Salmonella enterica serovar Typhimurium is one of the most prevalent Salmonella serotypes in the world and is a leading cause of food-borne salmonellosis. S. Typhimurium has been known to cause persistent infection and a wealth of investigations on Salmonella persisters indicates that toxin and antitoxin modules play a role in mediating the phenotypic switch of persisters, rendering its survival ability in the presence of antimicrobial agents. In this review, we discuss findings regarding mechanisms that underly persistence in S. Typhimurium, especially the involvement of toxin and antitoxin modules.
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Affiliation(s)
- Made Rai Dwitya Wiradiputra
- Antimicrobial Resistance Interdisciplinary Group (AmRIG), Faculty of Pharmacy, Mahidol University, Bangkok, Thailand,Biopharmaceutical Sciences Program, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand
| | - Piyatip Khuntayaporn
- Antimicrobial Resistance Interdisciplinary Group (AmRIG), Faculty of Pharmacy, Mahidol University, Bangkok, Thailand,Department of Microbiology, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand
| | - Krit Thirapanmethee
- Antimicrobial Resistance Interdisciplinary Group (AmRIG), Faculty of Pharmacy, Mahidol University, Bangkok, Thailand,Department of Microbiology, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand
| | - Mullika Traidej Chomnawang
- Antimicrobial Resistance Interdisciplinary Group (AmRIG), Faculty of Pharmacy, Mahidol University, Bangkok, Thailand,Department of Microbiology, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand,Correspondence: Mullika Traidej Chomnawang, Department of Microbiology, Faculty of Pharmacy, Mahidol University, Bangkok, 10400, Thailand, Tel +66 2 644 8692, Email
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8
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The potential role of ischaemia-reperfusion injury in chronic, relapsing diseases such as rheumatoid arthritis, Long COVID, and ME/CFS: evidence, mechanisms, and therapeutic implications. Biochem J 2022; 479:1653-1708. [PMID: 36043493 PMCID: PMC9484810 DOI: 10.1042/bcj20220154] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 02/07/2023]
Abstract
Ischaemia–reperfusion (I–R) injury, initiated via bursts of reactive oxygen species produced during the reoxygenation phase following hypoxia, is well known in a variety of acute circumstances. We argue here that I–R injury also underpins elements of the pathology of a variety of chronic, inflammatory diseases, including rheumatoid arthritis, ME/CFS and, our chief focus and most proximally, Long COVID. Ischaemia may be initiated via fibrin amyloid microclot blockage of capillaries, for instance as exercise is started; reperfusion is a necessary corollary when it finishes. We rehearse the mechanistic evidence for these occurrences here, in terms of their manifestation as oxidative stress, hyperinflammation, mast cell activation, the production of marker metabolites and related activities. Such microclot-based phenomena can explain both the breathlessness/fatigue and the post-exertional malaise that may be observed in these conditions, as well as many other observables. The recognition of these processes implies, mechanistically, that therapeutic benefit is potentially to be had from antioxidants, from anti-inflammatories, from iron chelators, and via suitable, safe fibrinolytics, and/or anti-clotting agents. We review the considerable existing evidence that is consistent with this, and with the biochemical mechanisms involved.
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9
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Gao R, Zhang J, Geng H, Wang Y, Kang X, Geng S, Jiao X, Barrow P. The Loss of focA Gene Increases the Ability of Salmonella Enteritidis to Exit from Macrophages and Boosts Early Extraintestinal Spread for Systemic Infection in a Mouse Model. Microorganisms 2022; 10:microorganisms10081557. [PMID: 36013975 PMCID: PMC9414335 DOI: 10.3390/microorganisms10081557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/27/2022] [Accepted: 07/30/2022] [Indexed: 11/29/2022] Open
Abstract
Salmonella Enteritidis (SE) can spread from the intestines to cause systemic infection, mainly involving macrophages. Intramacrophage Salmonella exits and reinfects neighboring cells, leading to severe disease. Salmonella genes involved in exiting from macrophages are not well understood or fully identified. A focA::Tn5 mutant was identified by an in vitro assay, with increased ability to exit from macrophages. A defined SEΔfocA mutant and its complemented derivative strain, SEΔfocA::focA, were constructed to confirm this phenotype. Although the lethal ability of focA mutants was similar to that of the parental SE in mice, it was isolated earlier from the liver and spleen than the parental SE. focA mutants induced higher levels of proinflammatory IL-12 and TNF-α compared with the parental SE and SEΔfocA::focA. focA mutants showed higher cytotoxicity and lower formate concentrations than SE and SEΔfocA::focA, whereas there was no change in pyroptosis, apoptosis and flagella formation ability. These current data suggest that the focA gene plays an important role in regulating intramacrophage Salmonella exiting and extraintestinal spread in mice, although the specific mechanism requires further in-depth studies.
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Affiliation(s)
- Ran Gao
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; (R.G.); (J.Z.); (H.G.); (Y.W.); (X.K.); (X.J.)
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou 225009, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
| | - Jian Zhang
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; (R.G.); (J.Z.); (H.G.); (Y.W.); (X.K.); (X.J.)
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou 225009, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
| | - Haoyu Geng
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; (R.G.); (J.Z.); (H.G.); (Y.W.); (X.K.); (X.J.)
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou 225009, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
| | - Yaonan Wang
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; (R.G.); (J.Z.); (H.G.); (Y.W.); (X.K.); (X.J.)
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou 225009, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
| | - Xilong Kang
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; (R.G.); (J.Z.); (H.G.); (Y.W.); (X.K.); (X.J.)
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou 225009, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
| | - Shizhong Geng
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; (R.G.); (J.Z.); (H.G.); (Y.W.); (X.K.); (X.J.)
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou 225009, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
- Correspondence: ; Tel.: +86-(514)-87971136; Fax: +86-(514)-87991747
| | - Xin’an Jiao
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; (R.G.); (J.Z.); (H.G.); (Y.W.); (X.K.); (X.J.)
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou 225009, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
| | - Paul Barrow
- School of Veterinary Medicine, University of Surrey, Daphne Jackson Road, Guildford GU2 7AL, UK;
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Peptidoglycan editing in non-proliferating intracellular Salmonella as source of interference with immune signaling. PLoS Pathog 2022; 18:e1010241. [PMID: 35077524 PMCID: PMC8815878 DOI: 10.1371/journal.ppat.1010241] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/04/2022] [Accepted: 01/01/2022] [Indexed: 02/07/2023] Open
Abstract
Salmonella enterica causes intracellular infections that can be limited to the intestine or spread to deeper tissues. In most cases, intracellular bacteria show moderate growth. How these bacteria face host defenses that recognize peptidoglycan, is poorly understood. Here, we report a high-resolution structural analysis of the minute amounts of peptidoglycan purified from S. enterica serovar Typhimurium (S. Typhimurium) infecting fibroblasts, a cell type in which this pathogen undergoes moderate growth and persists for days intracellularly. The peptidoglycan of these non-proliferating bacteria contains atypical crosslinked muropeptides with stem peptides trimmed at the L-alanine-D-glutamic acid-(γ) or D-glutamic acid-(γ)-meso-diaminopimelic acid motifs, both sensed by intracellular immune receptors. This peptidoglycan has a reduced glycan chain average length and ~30% increase in the L,D-crosslink, a type of bridge shared by all the atypical crosslinked muropeptides identified. The L,D-transpeptidases LdtD (YcbB) and LdtE (YnhG) are responsible for the formation of these L,D-bridges in the peptidoglycan of intracellular bacteria. We also identified in a fraction of muropeptides an unprecedented modification in the peptidoglycan of intracellular S. Typhimurium consisting of the amino alcohol alaninol replacing the terminal (fourth) D-alanine. Alaninol was still detectable in the peptidoglycan of a double mutant lacking LdtD and LdtE, thereby ruling out the contribution of these enzymes to this chemical modification. Remarkably, all multiple mutants tested lacking candidate enzymes that either trim stem peptides or form the L,D-bridges retain the capacity to modify the terminal D-alanine to alaninol and all attenuate NF-κB nuclear translocation. These data inferred a potential role of alaninol-containing muropeptides in attenuating pro-inflammatory signaling, which was confirmed with a synthetic tetrapeptide bearing such amino alcohol. We suggest that the modification of D-alanine to alaninol in the peptidoglycan of non-proliferating intracellular S. Typhimurium is an editing process exploited by this pathogen to evade immune recognition inside host cells. The peptidoglycan, built as a giant polymer of glycan chains crosslinked with short peptides, is essential for cell shape and survival in most bacteria. Its unique chemistry is recognized by innate immune receptors, thereby enabling neutralization of invading microbes. A striking feature of the peptidoglycan is its constant remodeling by a plethora of endogenous enzymes. In addition, some bacterial pathogens introduce structural modifications that interfere with immune recognition. These modifications have been characterized in pathogens mostly in laboratory nutrient media. Whether facultative intracellular pathogens modify peptidoglycan structure inside host cells, was unknown. The work presented here shows that non-proliferating Salmonella enterica serovar Typhimurium remodels the peptidoglycan structure in response to intracellular cues and that some of these modifications involve unprecedented changes as the presence of an amino alcohol that hampers activation of the master immune regulator NF-κB. Peptidoglycan editing might therefore empower persistence of bacterial pathogens in the intracellular niche.
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Bacillus coagulans protect against Salmonella enteritidis-induced intestinal mucosal damage in young chickens by inducing the differentiation of goblet cells. Poult Sci 2021; 101:101639. [PMID: 35016049 PMCID: PMC8749329 DOI: 10.1016/j.psj.2021.101639] [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: 09/01/2021] [Revised: 11/19/2021] [Accepted: 11/25/2021] [Indexed: 12/22/2022] Open
Abstract
Bacillus coagulans (B. coagulans) have proven to be effective in improving the development of gut immunity and microbiome, and offering protection against pathogens, especially in young animals. The newborn chicks are highly vulnerable to the foodborne pathogenic Salmonella infections, leading to high mortality and economic loss. However, whether B. coagulans can protect young chickens from Salmonella-induced intestinal mucosal damage by modulating the development of intestinal epithelium remains unclear. In this study, B. coagulans with excellent anti-Salmonella property was selected and used. The results showed that B. coagulans alleviated the morphological damage, intestinal inflammation and body weight loss caused by Salmonella enteritidis (S. enteritidis) infections. B. coagulans significantly increased the crypt depth. Furthermore, the goblet cell loss and downregulating of mucin 2 induced by S. enteritidis were all relieved by B. coagulans treatment. Consistently, the expression of the related genes of Notch signaling pathway was also upregulated in the S. enteritidis group but inhibited by B. coagulans. In addition, B. coagulans improved the levels of immunoglobulin A, superoxide dismutase, total antioxidant capacity, and avian beta-defensin 2 in the intestinal mucosa. This study demonstrated that B. coagulans could regulate the development of intestinal epithelium, protect the intestinal barrier, thus relieve infections with S. enteritidis in chicks, which can be used as alternatives to antibiotics in poultry feed.
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Staphylococcal Bacterial Persister Cells, Biofilms, and Intracellular Infection Are Disrupted by JD1, a Membrane-Damaging Small Molecule. mBio 2021; 12:e0180121. [PMID: 34634935 PMCID: PMC8510524 DOI: 10.1128/mbio.01801-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Rates of antibiotic and multidrug resistance are rapidly rising, leaving fewer options for successful treatment of bacterial infections. In addition to acquiring genetic resistance, many pathogens form persister cells, form biofilms, and/or cause intracellular infections that enable bacteria to withstand antibiotic treatment and serve as a source of recurring infections. JD1 is a small molecule previously shown to kill Gram-negative bacteria under conditions where the outer membrane and/or efflux pumps are disrupted. We show here that JD1 rapidly disrupts membrane potential and kills Gram-positive bacteria. Further investigation revealed that treatment with JD1 disrupts membrane barrier function and causes aberrant membranous structures to form. Additionally, exposure to JD1 reduced the number of Staphylococcus aureus and Staphylococcus epidermidis viable persister cells within broth culture by up to 1,000-fold and reduced the matrix and cell volume of biofilms that had been established for 24 h. Finally, we show that JD1 reduced the number of recoverable methicillin-resistant S. aureus organisms from infected cells. These observations indicate that JD1 inhibits staphylococcal cells in difficult-to-treat growth stages as well as, or better than, current clinical antibiotics. Thus, JD1 shows the importance of testing compounds under conditions that are relevant to infection, demonstrates the utility that membrane-targeting compounds have against multidrug-resistant bacteria, and indicates that small molecules that target bacterial cell membranes may serve as potent broad-spectrum antibacterials.
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Wang MY, Tang NJ. The correlation between Google trends and salmonellosis. BMC Public Health 2021; 21:1575. [PMID: 34416859 PMCID: PMC8379030 DOI: 10.1186/s12889-021-11615-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 07/29/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Salmonella infection (salmonellosis) is a common infectious disease leading to gastroenteritis, dehydration, uveitis, etc. Internet search is a new method to monitor the outbreak of infectious disease. An internet-based surveillance system using internet data is logistically advantageous and economical to show term-related diseases. In this study, we tried to determine the relationship between salmonellosis and Google Trends in the USA from January 2004 to December 2017. METHODS We downloaded the reported salmonellosis in the USA from the National Outbreak Reporting System (NORS) from January 2004 to December 2017. Additionally, we downloaded the Google search terms related to salmonellosis from Google Trends in the same period. Cross-correlation analysis and multiple regression analysis were conducted. RESULTS The results showed that 6 Google Trends search terms appeared earlier than reported salmonellosis, 26 Google Trends search terms coincided with salmonellosis, and 16 Google Trends search terms appeared after salmonellosis were reported. When the search terms preceded outbreaks, "foods" (t = 2.927, P = 0.004) was a predictor of salmonellosis. When the search terms coincided with outbreaks, "hotel" (t = 1.854, P = 0.066), "poor sanitation" (t = 2.895, P = 0.004), "blueberries" (t = 2.441, P = 0.016), and "hypovolemic shock" (t = 2.001, P = 0.047) were predictors of salmonellosis. When the search terms appeared after outbreaks, "ice cream" (t = 3.077, P = 0.002) was the predictor of salmonellosis. Finally, we identified the most important indicators of Google Trends search terms, including "hotel" (t = 1.854, P = 0.066), "poor sanitation" (t = 2.895, P = 0.004), "blueberries" (t = 2.441, P = 0.016), and "hypovolemic shock" (t = 2.001, P = 0.047). In the future, the increased search activities of these terms might indicate the salmonellosis. CONCLUSION We evaluated the related Google Trends search terms with salmonellosis and identified the most important predictors of salmonellosis outbreak.
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Affiliation(s)
- Ming-Yang Wang
- Department of Occupational and Environmental Health, School of Public Health, Tianjin Medical University, Tianjin, 300070, China.,Tianjin Key Laboratory of Environment, Nutrition, and Public Health, Tianjin Medical University, Tianjin, 300070, China.,Beijing Tongren Eye Center, Beijing Ophthalmology& Visual Sciences Key Laboratory, Beijing Tongren Hospital Affiliated to Capital University of Medical Sciences, Beijing, 100730, China
| | - Nai-Jun Tang
- Department of Occupational and Environmental Health, School of Public Health, Tianjin Medical University, Tianjin, 300070, China. .,Tianjin Key Laboratory of Environment, Nutrition, and Public Health, Tianjin Medical University, Tianjin, 300070, China.
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Analysis of In Vivo Transcriptome of Intracellular Bacterial Pathogen Salmonella enterica serovar Typhmurium Isolated from Mouse Spleen. Pathogens 2021; 10:pathogens10070823. [PMID: 34209260 PMCID: PMC8308634 DOI: 10.3390/pathogens10070823] [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] [Received: 06/09/2021] [Revised: 06/28/2021] [Accepted: 06/28/2021] [Indexed: 11/16/2022] Open
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium) is an important intracellular pathogen that poses a health threat to humans. This study tries to clarify the mechanism of Salmonella survival and reproduction in the host. In this study, high-throughput sequencing analysis was performed on RNA extracted from the strains isolated from infected mouse spleens and an S. Typhimurium reference strain (ATCC 14028) based on the BGISEQ-500 platform. A total of 1340 significant differentially expressed genes (DEGs) were screened. Functional annotation revealed DEGs associated with regulation, metabolism, transport and binding, pathogenesis, and motility. Through data mining and literature retrieval, 26 of the 58 upregulated DEGs (FPKM > 10) were not reported to be related to the adaptation to intracellular survival and were classified as candidate key genes (CKGs) for survival and proliferation in vivo. Our data contribute to our understanding of the mechanisms used by Salmonella to regulate virulence gene expression whilst replicating inside mammalian cells.
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A small molecule that mitigates bacterial infection disrupts Gram-negative cell membranes and is inhibited by cholesterol and neutral lipids. PLoS Pathog 2020; 16:e1009119. [PMID: 33290418 PMCID: PMC7748285 DOI: 10.1371/journal.ppat.1009119] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 12/18/2020] [Accepted: 11/01/2020] [Indexed: 01/01/2023] Open
Abstract
Infections caused by Gram-negative bacteria are difficult to fight because these pathogens exclude or expel many clinical antibiotics and host defense molecules. However, mammals have evolved a substantial immune arsenal that weakens pathogen defenses, suggesting the feasibility of developing therapies that work in concert with innate immunity to kill Gram-negative bacteria. Using chemical genetics, we recently identified a small molecule, JD1, that kills Salmonella enterica serovar Typhimurium (S. Typhimurium) residing within macrophages. JD1 is not antibacterial in standard microbiological media, but rapidly inhibits growth and curtails bacterial survival under broth conditions that compromise the outer membrane or reduce efflux pump activity. Using a combination of cellular indicators and super resolution microscopy, we found that JD1 damaged bacterial cytoplasmic membranes by increasing fluidity, disrupting barrier function, and causing the formation of membrane distortions. We quantified macrophage cell membrane integrity and mitochondrial membrane potential and found that disruption of eukaryotic cell membranes required approximately 30-fold more JD1 than was needed to kill bacteria in macrophages. Moreover, JD1 preferentially damaged liposomes with compositions similar to E. coli inner membranes versus mammalian cell membranes. Cholesterol, a component of mammalian cell membranes, was protective in the presence of neutral lipids. In mice, intraperitoneal administration of JD1 reduced tissue colonization by S. Typhimurium. These observations indicate that during infection, JD1 gains access to and disrupts the cytoplasmic membrane of Gram-negative bacteria, and that neutral lipids and cholesterol protect mammalian membranes from JD1-mediated damage. Thus, it may be possible to develop therapeutics that exploit host innate immunity to gain access to Gram-negative bacteria and then preferentially damage the bacterial cell membrane over host membranes.
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Xie Z, Zhang Y, Huang X. Evidence and speculation: the response of Salmonella confronted by autophagy in macrophages. Future Microbiol 2020; 15:1277-1286. [PMID: 33026883 DOI: 10.2217/fmb-2020-0125] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bacteria of the Salmonella genus cause diseases ranging from self-limited gastroenteritis to typhoid fever. Macrophages are immune cells that engulf and restrict Salmonella. These cells will carry Salmonella into the circulatory system and provoke a systemic infection. Therefore, the interaction between macrophages and intracellular Salmonella is vital for its pathogenicity. As one of the immune responses of macrophages, autophagy, along with the fusion of autophagosomes with lysosomes, occupies an important position in eliminating Salmonella. However, Salmonella that can overcome cellular defensive responses and infect neighboring cells must derive strategies to escape autophagy. This review introduces novel findings on Salmonella and macrophage autophagy as a mechanism against infection and explores the strategies used by Salmonella to escape autophagy.
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Affiliation(s)
- Zhongyi Xie
- Department of Biochemistry & Molecular Biology, Jiangsu University School of Medicine, Zhenjiang, Jiangsu 212013, China.,International Genome Center, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Ying Zhang
- Department of Biochemistry & Molecular Biology, Jiangsu University School of Medicine, Zhenjiang, Jiangsu 212013, China
| | - Xinxiang Huang
- Department of Biochemistry & Molecular Biology, Jiangsu University School of Medicine, Zhenjiang, Jiangsu 212013, China
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Bianchi F, van den Bogaart G. Vacuolar escape of foodborne bacterial pathogens. J Cell Sci 2020; 134:134/5/jcs247221. [PMID: 32873733 DOI: 10.1242/jcs.247221] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The intracellular pathogens Listeria monocytogenes, Salmonella enterica, Shigella spp. and Staphylococcus aureus are major causes of foodborne illnesses. Following the ingestion of contaminated food or beverages, pathogens can invade epithelial cells, immune cells and other cell types. Pathogens survive and proliferate intracellularly via two main strategies. First, the pathogens can remain in membrane-bound vacuoles and tailor organellar trafficking to evade host-cell defenses and gain access to nutrients. Second, pathogens can rupture the vacuolar membrane and proliferate within the nutrient-rich cytosol of the host cell. Although this virulence strategy of vacuolar escape is well known for L. monocytogenes and Shigella spp., it has recently become clear that S. aureus and Salmonella spp. also gain access to the cytosol, and that this is important for their survival and growth. In this Review, we discuss the molecular mechanisms of how these intracellular pathogens rupture the vacuolar membrane by secreting a combination of proteins that lyse the membranes or that remodel the lipids of the vacuolar membrane, such as phospholipases. In addition, we also propose that oxidation of the vacuolar membrane also contributes to cytosolic pathogen escape. Understanding these escape mechanisms could aid in the identification of new therapeutic approaches to combat foodborne pathogens.
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Affiliation(s)
- Frans Bianchi
- Department of Molecular Immunology and Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9722GR Groningen, The Netherlands
| | - Geert van den Bogaart
- Department of Molecular Immunology and Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9722GR Groningen, The Netherlands .,Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 9625GA Nijmegen, The Netherlands
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Nagy TA, Crooks AL, Quintana JLJ, Detweiler CS. Clofazimine Reduces the Survival of Salmonella enterica in Macrophages and Mice. ACS Infect Dis 2020; 6:1238-1249. [PMID: 32272013 DOI: 10.1021/acsinfecdis.0c00023] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Drug resistant pathogens are on the rise, and new treatments are needed for bacterial infections. Efforts toward antimicrobial discovery typically identify compounds that prevent bacterial growth in microbiological media. However, the microenvironments to which pathogens are exposed during infection differ from rich media and alter the biology of the pathogen. We and others have therefore developed screening platforms that identify compounds that disrupt pathogen growth within cultured mammalian cells. Our platform focuses on Gram-negative bacterial pathogens, which are of particular clinical concern. We screened a panel of 707 drugs to identify those with efficacy against Salmonella enterica Typhimurium growth within macrophages. One of the drugs identified, clofazimine (CFZ), is an antibiotic used to treat mycobacterial infections that is not recognized for potency against Gram-negative bacteria. We demonstrated that in macrophages CFZ enabled the killing of S. Typhimurium at single digit micromolar concentrations, and in mice, CFZ reduced tissue colonization. We confirmed that CFZ does not inhibit the growth of S. Typhimurium and E. coli in standard microbiological media. However, CFZ prevents bacterial replication under conditions consistent with the microenvironment of macrophage phagosomes, in which S. Typhimurium resides during infection: low pH, low magnesium and phosphate, and the presence of certain cationic antimicrobial peptides. These observations suggest that in macrophages and mice the efficacy of CFZ against S. Typhimurium is facilitated by multiple aspects of soluble innate immunity. Thus, systematic screens of existing drugs for infection-based potency are likely to identify unexpected opportunities for repurposing drugs to treat difficult pathogens.
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Affiliation(s)
- Toni A. Nagy
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado 80309, United States
| | - Amy L. Crooks
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado 80309, United States
| | - Joaquin L. J. Quintana
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado 80309, United States
| | - Corrella S. Detweiler
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado 80309, United States
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Castanheira S, López-Escarpa D, Pucciarelli MG, Cestero JJ, Baquero F, García-Del Portillo F. An alternative penicillin-binding protein involved in Salmonella relapses following ceftriaxone therapy. EBioMedicine 2020; 55:102771. [PMID: 32344200 PMCID: PMC7186495 DOI: 10.1016/j.ebiom.2020.102771] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/09/2020] [Accepted: 04/14/2020] [Indexed: 11/17/2022] Open
Abstract
Background Salmonella causes intracellular infections in humans. Besides quinolones, third generation cephalosporins are first line drugs used for salmonellosis therapy. An unresolved anomaly of this practice involves high relapse rates associated to quinolone- or cephalosporin-susceptible Salmonella isolates in patients that are discharged clinically following initial recovery. Reduced drug accessibility to intracellular locations has been hypothesized to impair pathogen eradication although supporting evidence is lacking in vivo. Here, we uncover a novel penicillin-binding protein as the first Salmonella factor likely contributing to relapse following beta-lactam, mainly ceftriaxone, therapy. Methods We used Salmonella enterica serovar Typhimurium mutants lacking the alternative penicillin-binding proteins PBP2SAL or PBP3SAL. Affinity of PBP2SAL and PBP3SAL for beta-lactam antibiotics was tested. Relapse after ceftriaxone therapy was analysed in the murine typhoid model. Findings S. Typhimurium does not express PBP2SAL or PBP3SAL in the Mueller-Hinton medium used for susceptibility testing. The pathogen produces these PBPs in response to acidic pH and nutrient limitation, conditions found in phagosomes of mammalian cells. PBP3SAL has low affinity for beta-lactams, even at acidic pH. In vitro susceptibility to ceftriaxone at low pH is strongly reduced. S. Typhimurium lacking PBP3SAL was unable to cause relapse in mice following ceftriaxone therapy. Interpretation The reduced capacity of ceftriaxone to clear S. Typhimurium in vivo is favoured by a switch in beta-lactam targets. This switch, involving production of the less-susceptible PBP3SAL, remains invisible for standard procedures used in clinical therapy. We conclude that eradication of salmonellosis will be possible only upon targeting of PBP3SAL with novel drugs.
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Affiliation(s)
- Sónia Castanheira
- Laboratory de Intracellular Bacterial Pathogens. National Centre for Biotechnology (CNB)-CSIC, Darwin 3, E-28049 Madrid, Spain
| | - David López-Escarpa
- Laboratory de Intracellular Bacterial Pathogens. National Centre for Biotechnology (CNB)-CSIC, Darwin 3, E-28049 Madrid, Spain
| | - M Graciela Pucciarelli
- Laboratory de Intracellular Bacterial Pathogens. National Centre for Biotechnology (CNB)-CSIC, Darwin 3, E-28049 Madrid, Spain; Department of Molecular Biology, University Autónoma of Madrid, Centre of Molecular Biology 'Severo Ochoa' (CBMSO)-CSIC, E-28049 Madrid, Spain
| | - Juan J Cestero
- Laboratory de Intracellular Bacterial Pathogens. National Centre for Biotechnology (CNB)-CSIC, Darwin 3, E-28049 Madrid, Spain
| | - Fernando Baquero
- Department of Microbiology, Ramón y Cajal University Hospital, IRYCIS, Madrid, Spain
| | - Francisco García-Del Portillo
- Laboratory de Intracellular Bacterial Pathogens. National Centre for Biotechnology (CNB)-CSIC, Darwin 3, E-28049 Madrid, Spain.
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Xie S, Li Y, Zhao S, Lv Y, Yu Q. Salmonella infection induced intestinal crypt hyperplasia through Wnt/β-catenin pathway in chicken. Res Vet Sci 2020; 130:179-183. [PMID: 32199176 DOI: 10.1016/j.rvsc.2020.03.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/14/2020] [Accepted: 03/02/2020] [Indexed: 01/13/2023]
Abstract
S. Pullorum is a causative agent of enteric disease of poultry with serious diarrhea. However, the detailed mechanism behind its injury to intestinal mucosa barrier, especially for intestinal stem cells, is unclear. In this study, S. Pullorum were orally administrated to 3 days old chicken to investigate the pathogenesis of S. Pullorum on intestinal mucosal barrier, especially on the proliferation of epithelial cells. We found that S. Pullorum could colonize in the cecum and invade into the liver through intestinal mucosa damage, which caused obvious pathological changes in liver and intestine and even leaded to death, as well as significant reduction of body weight. We also found that S. Pullorum infection enhanced the mRNA expression of IL-1β and IL-6 through TLR4/MyD88 pathway, which was also further verified by the increased lipopolysaccharide (LPS) levels in serum. Furthermore, S. Pullorum increased the depth of crypt and density of PCNA+ cells significantly through the over-activation of Wnt/β-catenin signaling pathway. The expression of intestinal stem cells markers Lgr5 and Bmi1 was also increased after S. Pullorum infection to support the crypt hyperplasia. In addition, we verified that S. Pullorum infection enhanced the mRNA expression of IL-1β, TLR4, Lgr5 and Bmi1. Our study indicated that S. Pullorum infection damaged the intestinal mucosa barrier to induce diarrhea, affected the abnormal proliferation of intestinal stem cells by over-activation of Wnt/β-catenin pathway in chicken.
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Affiliation(s)
- Shuang Xie
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Weigang 1, Nanjing, Jiangsu 210095, PR China
| | - Yuchen Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Weigang 1, Nanjing, Jiangsu 210095, PR China
| | - Shiyi Zhao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Weigang 1, Nanjing, Jiangsu 210095, PR China
| | - Yingjun Lv
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Weigang 1, Nanjing, Jiangsu 210095, PR China.
| | - Qinghua Yu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Weigang 1, Nanjing, Jiangsu 210095, PR China.
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Jiang L, Lee HW, Loo SCJ. Therapeutic lipid-coated hybrid nanoparticles against bacterial infections. RSC Adv 2020; 10:8497-8517. [PMID: 35497832 PMCID: PMC9050015 DOI: 10.1039/c9ra10921h] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 02/14/2020] [Indexed: 12/26/2022] Open
Abstract
One of the most important health concerns in society is the development of pathogen-causing nosocomial infections. Since the first discovery of antibiotics, bacterial infections have been highly treatable. However, with evolution and the nondiscretionary usage of antibiotics, pathogens have also found new ways to survive the onslaught of antibiotics by surviving intracellularly or through the formation of obstinate biofilms, and through these, the outcomes of regular antibiotic treatments may now be unsatisfactory. Lipid-coated hybrid nanoparticles (LCHNPs) are the next-generation core–shell structured nanodelivery system, where an inorganic or organic core, loaded with antimicrobials, is enveloped by lipid layers. This core–shell structure, with multifarious decorations, not only improves the loading capabilities of therapeutics but also has the potential to improve therapeutic delivery, especially for targeting biofilm-based and intracellular bacterial infections. Although there has been significant interest in the development of LCHNPs, they have yet to be widely exploited for bacterial infections. In this review, we will provide an overview on the latest development of LCHNPs and the various approaches in synthesizing this nano-delivery system. In addition, a discussion on future perspectives of LCHNPs, in combination with other novel anti-bacterial technologies, will be provided towards the end of this review. Lipid-coated hybrid nanoparticles are next-generation core–shell structured nanodelivery systems, which improve the loading capabilities of therapeutics and can improve therapeutic delivery, especially for targeting biofilm-based and intracellular bacterial infections.![]()
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Affiliation(s)
- Lai Jiang
- School of Materials Science & Engineering
- Nanyang Technological University
- Singapore
| | - Hiang Wee Lee
- School of Materials Science & Engineering
- Nanyang Technological University
- Singapore
| | - Say Chye Joachim Loo
- School of Materials Science & Engineering
- Nanyang Technological University
- Singapore
- Singapore Centre for Environmental Life Sciences Engineering
- Nanyang Technological University
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Barcoded Consortium Infections Resolve Cell Type-Dependent Salmonella enterica Serovar Typhimurium Entry Mechanisms. mBio 2019; 10:mBio.00603-19. [PMID: 31113898 PMCID: PMC6529635 DOI: 10.1128/mbio.00603-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Salmonella enterica serovar Typhimurium (S.Tm) is a widespread and broad-host-spectrum enteropathogen with the capacity to invade diverse cell types. Still, the molecular basis for the host cell invasion process has largely been inferred from studies of a few selected cell lines. Our work resolves the mechanisms that Salmonellae employ to invade prototypical host cell types, i.e., human epithelial, monocyte, and macrophage cells, at a previously unattainable level of temporal and quantitative precision. This highlights efficient bacterium-driven entry into innate immune cells and uncovers a type III secretion system effector module that dominates active bacterial invasion of not only epithelial cells but also monocytes and macrophages. The results are derived from a generalizable method, where we combine barcoding of the bacterial chromosome with mixed consortium infections of cultured host cells. The application of this methodology across bacterial species and infection models will provide a scalable means to address host-pathogen interactions in diverse contexts. Bacterial host cell invasion mechanisms depend on the bacterium’s virulence factors and the properties of the target cell. The enteropathogen Salmonella enterica serovar Typhimurium (S.Tm) invades epithelial cell types in the gut mucosa and a variety of immune cell types at later infection stages. The molecular mechanism(s) of host cell entry has, however, been studied predominantly in epithelial cell lines. S.Tm uses a type three secretion system (TTSS-1) to translocate effectors into the host cell cytosol, thereby sparking actin ruffle-dependent entry. The ruffles also fuel cooperative invasion by bystander bacteria. In addition, several TTSS-1-independent entry mechanisms exist, involving alternative S.Tm virulence factors, or the passive uptake of bacteria by phagocytosis. However, it remains ill-defined how S.Tm invasion mechanisms vary between host cells. Here, we developed an internally controlled and scalable method to map S.Tm invasion mechanisms across host cell types and conditions. The method relies on host cell infections with consortia of chromosomally tagged wild-type and mutant S.Tm strains, where the abundance of each strain can be quantified by qPCR or amplicon sequencing. Using this methodology, we quantified cooccurring TTSS-1-dependent, cooperative, and TTSS-1-independent invasion events in epithelial, monocyte, and macrophage cells. We found S.Tm invasion of epithelial cells and monocytes to proceed by a similar MOI-dependent mix of TTSS-1-dependent and cooperative mechanisms. TTSS-1-independent entry was more frequent in macrophages. Still, TTSS-1-dependent invasion dominated during the first minutes of interaction also with this cell type. Finally, the combined action of the SopB/SopE/SopE2 effectors was sufficient to explain TTSS-1-dependent invasion across both epithelial and phagocytic cells.
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Winarsih S, Kosasih T, Putera MA, Rahmadhiani N, Poernomo EL, Runtuk KS, Oswari MV. β-Glucan of Candida albicans Cell Wall Extract Inhibits Salmonella Typhimurium Colonization by Potentiating Cellular Immunity (CD8 + and CD4 + T Cells). Rev Soc Bras Med Trop 2019; 52:e20180254. [PMID: 30726315 DOI: 10.1590/0037-8682-0254-2018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 12/20/2018] [Indexed: 11/21/2022] Open
Abstract
INTRODUCTION Antimicrobial resistance has been reported in the drugs used for the treatment of typhoid fever. The immunomodulatory substance β-glucan can be used as an alternative therapy as it potentiates host immunity. The aims of this study are to observe the effect of Candida albicans cell wall (CCW) extract towards host immunity (TCD8+ and TCD4+ cells in spleen, intestinal sIgA) and its capacity to kill Salmonella in the intestine and liver of typhoid fever mice models. METHODS Typhoid fever mice models were created by infecting mice with S. Typhimurium orally. Mice were divided into four groups: the Non-Infected, Infected, CCW (infected mice treated with 300 µg CCW extract/mouse once a day), and Ciprofloxacin groups (infected mice treated with 15 mg/kg BW ciprofloxacin twice a day). RESULTS Secretory IgA (sIgA) concentrations of mice in the CCW group remained unchanged. However, their TCD4+ and TCD8+ cells increased substantially compared to those in the Non-Infected group. In the Ciprofloxacin group, sIgA concentrations increased markedly compared to those in the Non-Infected and CCW groups; TCD4+ and TCD8+ cells also increased significantly compared to those in the Infected Group, but not significant compared to those in the CCW group. Colonization of S. Typhimurium in the intestine and liver decreased significantly in the CCW and Ciprofloxacin groups compared to that in the Infected group, with the lowest reduction being found in the Ciprofloxacin group. CONCLUSIONS The inhibition of S. Typhimurium colonization by CCW is associated with the increase in TCD4+ and TCD8+ cells.
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Affiliation(s)
- Sri Winarsih
- Pharmacy Study Program, Faculty of Medicine, Universitas Brawijaya, Indonesia
| | - Tomson Kosasih
- Pharmacy Study Program, Faculty of Medicine, Universitas Brawijaya, Indonesia
| | | | - Nayla Rahmadhiani
- Medicine Study Program, Faculty of Medicine, Universitas Brawijaya, Indonesia
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Norkowski S, Schmidt MA, Rüter C. The species-spanning family of LPX-motif harbouring effector proteins. Cell Microbiol 2018; 20:e12945. [PMID: 30137651 DOI: 10.1111/cmi.12945] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/09/2018] [Accepted: 08/14/2018] [Indexed: 12/13/2022]
Abstract
The delivery of effector proteins into infected eukaryotic cells represents a key virulence feature of many microbial pathogens in order to derail essential cellular processes and effectively counter the host defence system. Although bacterial effectors are truly numerous and exhibit a wide range of biochemical activities, commonalities in terms of protein structure and function shared by many bacterial pathogens exist. Recent progress has shed light on a species-spanning family of bacterial effectors containing an LPX repeat motif as a subtype of the leucine-rich repeat superfamily, partially combined with a novel E3 ubiquitin ligase domain. This review highlights the immunomodulatory effects of LPX effector proteins, with particular emphasis on the exploitation of the host ubiquitin system.
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Affiliation(s)
- Stefanie Norkowski
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany
| | - M Alexander Schmidt
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany
| | - Christian Rüter
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany
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