1
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Sun M, Fang Y, Zheng J, Shi G, Guo J, Zhang X, Zhang R. Role of symbiotic microbiota dysbiosis in the progression of chronic kidney disease accompanied with vascular calcification. Front Pharmacol 2024; 14:1306125. [PMID: 38249346 PMCID: PMC10796560 DOI: 10.3389/fphar.2023.1306125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 12/11/2023] [Indexed: 01/23/2024] Open
Abstract
Background: Chronic kidney disease (CKD) is now globally recognized as a critical public health concern. Vascular calcification (VC) represents a significant risk factor for cardiovascular events in individuals with CKD. It is the accessible and precise diagnostic biomarkers for monitoring the progression of CKD and the concurrent VC are urgently needed. Methods: The adenine diet-induced CKD rat model was utilized to investigate chronic kidney injury, calcification in the kidney and thoracic aorta, and dysregulation of biochemical indices. Enzyme-linked immune sandwich assays were employed to analyze changes in calcification-related proteins. 16S rRNA sequencing was performed to delineate the microbiota characteristics in the gut and blood of CKD-afflicted rats. Additionally, transcriptome sequencing of kidney tissue was conducted to explore the relationship between CKD-associated microbiota features and alterations in kidney function. Results: The adenine diet-induced CKD inhibited body weight gain, and led to kidney injury, and pronounced calcification in kidney and thoracic aorta. The microbiota both in the gut and blood of these affected rats exhibited significantly lower alpha diversity and distinctive beta diversity than those in their healthy counterparts. CKD resulted in dysregulation of several biochemical indices (including elevated levels of creatinine, low-density lipoprotein-cholesterol, sodium, phosphorous, total cholesterol, and urea and decreased levels of albumin, calcium, lactate dehydrogenase, and total bilirubin). Moreover, it upregulated calcification-related factors (bone sialoprotein [BSP], Klotho, fibroblast growth factor [FGF]-23, and sclerostin [SOST]) and lipopolysaccharide (LPS). Notably, the increased Acinetobacter in the blood was positively associated with calcifications in the kidney and thoracic aorta, in addition to the positive correlation with gut microbiota. The enrichment of Acinetobacter was concurrent with increases in calcification factors (BSP, FGF-23, and SOST), LPS, and phosphorous. Furthermore, transcriptome sequencing revealed that the enrichment of Acinetobacter was positively correlated with the majority of upregulated genes and negatively correlated with downregulated genes involved in the mineral absorption pathway. Conclusion: Our findings, for the first time, underscore that dysbiosis of symbiotic microbiota, both in the gut and blood, is involved in the progression of CKD. Particularly, the enrichment of Acinetobacter in blood emerges as a potential risk factor for CKD and its accompanying VC.
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Affiliation(s)
- Mengying Sun
- Department of Nephrology, Zhuhai People's Hospital Affiliated with Jinan University, Jinan University, Zhuhai, Guangdong, China
| | - Yilong Fang
- School of Pharmaceutical Sciences, Affiliated Foshan Maternity and Child Healthcare Hospital, Southern Medical University, Foshan, China
| | - Jianhua Zheng
- Department of Traditional Chinese Medicine, Huizhou First Hospital, Huizhou, Guangdong, China
| | - Guojuan Shi
- Department of Nephrology, Zhuhai People's Hospital Affiliated with Jinan University, Jinan University, Zhuhai, Guangdong, China
| | - Junli Guo
- Department of Nephrology, Zhuhai People's Hospital Affiliated with Jinan University, Jinan University, Zhuhai, Guangdong, China
| | - Xinzhou Zhang
- Department of Nephrology, Shenzhen People's Hospital, The Second Clinical Medical College of Jinan University, Shenzhen, Guangdong, China
| | - Rui Zhang
- Department of Nephrology, Zhuhai People's Hospital Affiliated with Jinan University, Jinan University, Zhuhai, Guangdong, China
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Guo P, Jin L, Zhou H, Bao Y, Yang J, Chen J, He Y, Yu D, Wan H. Glycyrrhetinic acid protects against Multidrug-resistant Acinetobacter baumannii-induced lung epithelial cells injury by regulating inflammation and oxidative stress. BMC Pharmacol Toxicol 2023; 24:5. [PMID: 36717837 PMCID: PMC9887834 DOI: 10.1186/s40360-023-00648-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 01/25/2023] [Indexed: 02/01/2023] Open
Abstract
Glycyrrhetinic acid (GA) is a bio-effective component of Licorice. The GA is a monomer and the ingredient is an Oleanane-type pentacyclic triterpenes that has been used as a remedy for years. Due to the abuse of antibiotics, people pay attention to the emergence of Multidrug-resistant Acinetobacter baumannii (MDR-AB). As a conditional pathogen, MDR-AB causes severe infection, endangering human lives. Our previous studies found GA played an important role in Yinhua Pinggan, a Chinese medicine. However, whether GA could protect lung epithelium from MDR-AB-induced cell injury was elusive. Herein, we investigated the effects of GA on MDR-AB-infected A549 cells. The results showed GA had slightly antibacterial activity to MDR-AB in the GA (high concentration) but no impact on drug resistance genes. Notwithstanding, GA could reverse MDR-AB-induced cell apoptosis, hampered adhesion and invasion of MDR-AB to cells, and inhibit pro-inflammatory cytokines expression of IL-1β, IL-6, and TNF. Besides, MDR-AB-induced reactive oxygen species, pro-oxidative protein malonaldehyde, and myeloperoxidase of cells were decreased by GA, while antioxidative proteins were recovered, showing antioxidative capacity of GA might play a critical role. The expressions of toll-like receptor (TLRs) - 1, 2, 4, 5, 6, and 9 were increased by MDR-AB infection, while GA reversed the tendency. Interestingly, GA inhibited MDR-AB induced myeloiddifferentiationfactor88 expression (MYD88), one downstream con-factors of TLRs, but no affection on Interferon regulatory Factor 3 (IRF3), the other one, indicating GA inhibited MDR-AB induced cell injury by impact TLR/MYD88 pathway to attenuate inflammation. Altogether, our results demonstrated that GA protects against MDR-AB-induced cell injury through its antioxidative and anti-inflammatory properties, which deserve further study in the future.
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Affiliation(s)
- Piaoyi Guo
- grid.268505.c0000 0000 8744 8924Zhejiang Chinese Medical University, Hangzhou Zhejiang, 310053 PR China
| | - Liang Jin
- grid.268505.c0000 0000 8744 8924Zhejiang Chinese Medical University, Hangzhou Zhejiang, 310053 PR China
| | - Huifen Zhou
- grid.268505.c0000 0000 8744 8924Zhejiang Chinese Medical University, Hangzhou Zhejiang, 310053 PR China
| | - Yida Bao
- grid.268505.c0000 0000 8744 8924Zhejiang Chinese Medical University, Hangzhou Zhejiang, 310053 PR China
| | - Jiehong Yang
- grid.268505.c0000 0000 8744 8924Zhejiang Chinese Medical University, Hangzhou Zhejiang, 310053 PR China
| | - Jing Chen
- grid.268505.c0000 0000 8744 8924Zhejiang Chinese Medical University, Hangzhou Zhejiang, 310053 PR China
| | - Yu He
- grid.268505.c0000 0000 8744 8924Zhejiang Chinese Medical University, Hangzhou Zhejiang, 310053 PR China
| | - Daojun Yu
- grid.13402.340000 0004 1759 700XAffiliated Hangzhou First People’s Hospital, Zhejiang University of Medicine, Hangzhou, Zhejiang 310003 PR China
| | - Haitong Wan
- grid.268505.c0000 0000 8744 8924Zhejiang Chinese Medical University, Hangzhou Zhejiang, 310053 PR China
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3
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Khan MA, Allemailem KS, Maswadeh H, Younus H. Safety and Prophylactic Efficacy of Liposome-Based Vaccine against the Drug-Resistant Acinetobacter baumannii in Mice. Pharmaceutics 2022; 14:pharmaceutics14071357. [PMID: 35890253 PMCID: PMC9318010 DOI: 10.3390/pharmaceutics14071357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 06/23/2022] [Accepted: 06/24/2022] [Indexed: 12/01/2022] Open
Abstract
In recent years, the emergence of multidrug-resistant Acientobacter baumannii has greatly threatened public health and depleted our currently available antibacterial armory. Due to limited therapeutic options, the development of an effective vaccine formulation becomes critical in order to fight this drug-resistant pathogen. The objective of the present study was to develop a safe vaccine formulation that can be effective against A. baumannii infection and its associated complications. Here, we prepared liposomes-encapsulated whole cell antigens (Lip-WCAgs) as a vaccine formulation and investigated its prophylactic efficacy against the systemic infection of A. baumannii. The immunization with Lip-WCAgs induced the higher production of antigen-specific antibody titers, greater lymphocyte proliferation, and increased secretion of Th1 cytokines, particularly IFN-γ and IL-12. Antisera from Lip-WCAgs-immunized mice showed the utmost bactericidal activity and potently inhibited the biofilm formation by A. baumannii. Interestingly, Lip-WCAgs-induced immune response was translated in in vivo protection studies as the immunized mice exhibited the highest resistance to A. baumannii infection. Mice in the group immunized with Lip-WCAgs had an 80% survival rate and a bacterial burden of 5464 ± 1193 CFUs per gram of the lung tissue, whereas the mice immunized with IFA-WCAgs had a 50% survival rate and 51,521 ± 8066 CFUs. In addition, Lip-WCAgs vaccinated mice had lower levels of the inflammatory markers, including CRP, IL-6, IL-1β, and TNF-α. The findings of this study suggest that Lip-WCAgs may be considered a potential vaccine formulation to protect individuals against A. baumannii infection.
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Affiliation(s)
- Masood Alam Khan
- Department of Basic Health Sciences, College of Applied Medical Sciences, Qassim University, Buraydah 51452, Saudi Arabia
- Correspondence: ; Tel.: +966-(50)-7059437; Fax: +966-(63)-801628
| | - Khaled S. Allemailem
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah 51452, Saudi Arabia;
| | - Hamzah Maswadeh
- Department of Pharmaceutics, College of Pharmacy, Qassim University, Buraydah 51452, Saudi Arabia;
| | - Hina Younus
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India;
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Chai L, Wang Q, Si C, Gao W, Zhang L. Potential Association Between Changes in Microbiota Level and Lung Diseases: A Meta-Analysis. Front Med (Lausanne) 2022; 8:723635. [PMID: 35096850 PMCID: PMC8795898 DOI: 10.3389/fmed.2021.723635] [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: 06/28/2021] [Accepted: 12/14/2021] [Indexed: 11/27/2022] Open
Abstract
Objective: Lung microbiota is increasingly implicated in multiple types of respiratory diseases. However, no study has drawn a consistent conclusion regarding the relationship between changes in the microbial community and lung diseases. This study verifies the association between microbiota level and lung diseases by performing a meta-analysis. Methods: Literature databases, including PubMed, ISI Web of Science, Embase, Google Scholar, PMC, and CNKI, were used to collect related articles published before March 20, 2021. The standard mean deviation (SMD) and related 95% confidence intervals (CIs) were calculated using a random-effects model. Subgroup, sensitivity, and publication bias analyses were also conducted. Results: Six studies, comprising 695 patients with lung diseases and 176 healthy individuals, were included in this meta-analysis. The results indicated that the microbiota level was higher in patients with lung diseases than in healthy individuals (SMD = 0.39, 95% CI = 0.22–0.55, I2 = 91.5%, P < 0.01). Subgroup analysis based on country demonstrated that the microbiota level was significantly higher in Chinese (SMD = 1.90, 95% CI = 0.87–2.93, I2 = 62.3%, P < 0.01) and Korean (SMD = 0.24, 95% CI = 0.13–0.35, I2 = 78.7%, P < 0.01) patients with lung diseases. The microbiota level of patients with idiopathic pulmonary fibrosis (IPF) (SMD = 1.40, 95% CI = 0.42–2.38, I2 = 97.3%, P = 0.005), chronic obstructive pulmonary disease (COPD) (SMD = 0.30, 95% CI = 0.09–0.50, I2 = 83.9%, P = 0.004), and asthma (SMD = 0.19, 95% CI = 0.06–0.32, I2 = 69.4%, P = 0.004) were significantly higher than those of the healthy group, whereas a lower microbiota level was found in patients with chronic hypersensitivity pneumonitis (CHP). The microbiota level significantly increased when the disease sample size was >50. Subgroup analysis based on different microbiota genera, indicated that Acinetobacter baumannii and Pseudomonas aeruginosa were significantly increased in COPD and asthma diseases. Conclusion: We observed that patients with IPF, COPD, and asthma had a higher microbiota level, whereas patients with CHP had a lower microbiota level compared to the healthy individuals. The level of A. baumannii and P. aeruginosa were significantly higher in patients with COPD and asthma, and thus represented as potential microbiota markers in the diagnosis and treatment of lung diseases.
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Affiliation(s)
- Lan Chai
- Department of Rheumatology and Immunology Department, Zhejiang Hospital, Hangzhou, China
| | - Qi Wang
- College of Pharmacy, Harbin Medical University-Daqing, Daqing, China
| | - Caijuan Si
- Department of Nutrition, Zhejiang Hospital, Hangzhou, China
| | - Wenyan Gao
- Key Laboratory of Neuropsychiatric Drug Research of Zhejiang Province, Institute of Materia Medica, Zhejiang Academy of Medical Sciences and Hangzhou Medical College, Hangzhou, China
- *Correspondence: Wenyan Gao
| | - Lun Zhang
- Department of Nutrition, Zhejiang Hospital, Hangzhou, China
- Lun Zhang
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5
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Antimicrobial, Immunomodulatory and Anti-Inflammatory Potential of Liposomal Thymoquinone: Implications in the Treatment of Bacterial Pneumonia in Immunocompromised Mice. Biomedicines 2021; 9:biomedicines9111673. [PMID: 34829902 PMCID: PMC8615793 DOI: 10.3390/biomedicines9111673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 11/17/2022] Open
Abstract
Acinetobacter baumannii has recently been increasing as an aggressive pathogen in immunocompromised persons. In the present study, we determined the in vitro antibacterial and anti-biofilm activity of thymoquinone (TQ) against A. baumannii. A liposomal formulation of TQ (Lip-TQ) was prepared and its therapeutic potential was investigated in the treatment of A. baumannii infection in immunocompromised mice. Leukopenia was induced in mice by injecting cyclophosphamide (CYP) at a dose of 200 mg/kg and the leukopenic mice were infected with 1 × 106 CFUs of A. baumannii. The effectiveness of free TQ or Lip-TQ against A. baumannii infection was assessed by analyzing the survival rate and bacterial burden. Moreover, the efficacy of Lip-TQ was also studied by examining the systemic inflammatory markers and the histological changes in the lung tissues. The results showed that the mice in the group treated with Lip-TQ at a dose of 10 mg/kg exhibited a 60% survival rate on day 40 post-infection, whereas all the mice treated with free TQ at the same dose died within this duration. Likewise, the lowest bacterial burden was found in the lung tissue of mice treated with Lip-TQ (10 mg/kg). Besides, Lip-TQ treatment remarkably alleviated the infection-associated inflammation, oxidative stress, and histological changes in the lung tissues. Based on the findings of the present study, we recommend considering Lip-TQ as a valuable therapeutic formulation in the treatment of A. baumannii-associated pneumonia in immunocompromised subjects.
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6
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Efficacy of Lysophosphatidylcholine as Direct Treatment in Combination with Colistin against Acinetobacter baumannii in Murine Severe Infections Models. Antibiotics (Basel) 2021; 10:antibiotics10020194. [PMID: 33671416 PMCID: PMC7922394 DOI: 10.3390/antibiotics10020194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/10/2021] [Accepted: 02/13/2021] [Indexed: 01/28/2023] Open
Abstract
The stimulation of the immune response to prevent the progression of an infection may be an adjuvant to antimicrobial treatment. Here, we aimed to evaluate the efficacy of lysophosphatidylcholine (LPC) treatment in combination with colistin in murine experimental models of severe infections by Acinetobacter baumannii. We used the A. baumannii Ab9 strain, susceptible to colistin and most of the antibiotics used in clinical settings, and the A. baumannii Ab186 strain, susceptible to colistin but presenting a multidrug-resistant (MDR) pattern. The therapeutic efficacies of one and two LPC doses (25 mg/kg/d) and colistin (20 mg/kg/8 h), alone or in combination, were assessed against Ab9 and Ab186 in murine peritoneal sepsis and pneumonia models. One and two LPC doses combined with colistin and colistin monotherapy enhanced Ab9 and Ab186 clearance from spleen, lungs and blood and reduced mice mortality compared with those of the non-treated mice group in both experimental models. Moreover, one and two LPC doses reduced the bacterial concentration in tissues and blood in both models and increased mice survival in the peritoneal sepsis model for both strains compared with those of the colistin monotherapy group. LPC used as an adjuvant of colistin treatment may be helpful to reduce the severity and the resolution of the MDR A. baumannii infection.
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7
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Weidensdorfer M, Ishikawa M, Hori K, Linke D, Djahanschiri B, Iruegas R, Ebersberger I, Riedel-Christ S, Enders G, Leukert L, Kraiczy P, Rothweiler F, Cinatl J, Berger J, Hipp K, Kempf VAJ, Göttig S. The Acinetobacter trimeric autotransporter adhesin Ata controls key virulence traits of Acinetobacter baumannii. Virulence 2020; 10:68-81. [PMID: 31874074 PMCID: PMC6363060 DOI: 10.1080/21505594.2018.1558693] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Acinetobacter baumannii is a Gram-negative pathogen that causes a multitude of nosocomial infections. The Acinetobacter trimeric autotransporter adhesin (Ata) belongs to the superfamily of trimeric autotransporter adhesins which are important virulence factors in many Gram-negative species. Phylogenetic profiling revealed that ata is present in 78% of all sequenced A. baumannii isolates but only in 2% of the closely related species A. calcoaceticus and A. pittii. Employing a markerless ata deletion mutant of A. baumannii ATCC 19606 we show that adhesion to and invasion into human endothelial and epithelial cells depend on Ata. Infection of primary human umbilical cord vein endothelial cells (HUVECs) with A. baumannii led to the secretion of interleukin (IL)-6 and IL-8 in a time- and Ata-dependent manner. Furthermore, infection of HUVECs by WT A. baumannii was associated with higher rates of apoptosis via activation of caspases-3 and caspase-7, but not necrosis, in comparison to ∆ata. Ata deletion mutants were furthermore attenuated in their ability to kill larvae of Galleria mellonella and to survive in larvae when injected at sublethal doses. This indicates that Ata is an important multifunctional virulence factor in A. baumannii that mediates adhesion and invasion, induces apoptosis and contributes to pathogenicity in vivo.
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Affiliation(s)
- Marko Weidensdorfer
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Masahito Ishikawa
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Katsutoshi Hori
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Dirk Linke
- Department of Biosciences, Section for Genetics and Evolutionary Biology, University of Oslo, Oslo, Norway
| | - Bardya Djahanschiri
- Department for Applied Bioinformatics, Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt, Germany
| | - Ruben Iruegas
- Department for Applied Bioinformatics, Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt, Germany
| | - Ingo Ebersberger
- Department for Applied Bioinformatics, Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt, Germany.,Senckenberg Biodiversity and Climate Research Centre Frankfurt (BIK-F), Frankfurt, Germany
| | - Sara Riedel-Christ
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Giulia Enders
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Laura Leukert
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Peter Kraiczy
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Florian Rothweiler
- Institute of Medical Virology, University Hospital, Goethe University, Frankfurt, Germany
| | - Jindrich Cinatl
- Institute of Medical Virology, University Hospital, Goethe University, Frankfurt, Germany
| | - Jürgen Berger
- Electron Microscopy Facility, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Katharina Hipp
- Electron Microscopy Facility, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Volkhard A J Kempf
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Stephan Göttig
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
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8
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Zeng X, Gu H, Peng L, Yang Y, Wang N, Shi Y, Zou Q. Transcriptome Profiling of Lung Innate Immune Responses Potentially Associated With the Pathogenesis of Acinetobacter baumannii Acute Lethal Pneumonia. Front Immunol 2020; 11:708. [PMID: 32391015 PMCID: PMC7188829 DOI: 10.3389/fimmu.2020.00708] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 03/30/2020] [Indexed: 02/05/2023] Open
Abstract
Acinetobacter baumannii is one of the dominating causes of nosocomial pneumonia, however, very little is known about the host immune response associated with pathogenesis of A. baumannii infection. Here, we used a hypervirulent A. baumannii to establish an acute lethal pneumonia, supported by high bacterial burdens, severe inflammatory cells infiltration and lung damage. The lung transcriptome changes in response to A. baumannii lethal pneumonia were detected by RNA sequencing. The results showed that 6,288 host genes changed expression, with 3,313 upregulated genes and 2,975 downregulated genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that genes related to TNF, cytokine-cytokine receptor interaction, Toll-like receptor, NOD-like receptor, NF-κB, Jak-STAT, HIF-1 signaling pathways, apoptosis, and phagosome were significantly upregulated. Whereas, genes associated with PI3K-AKT signaling pathway, glycolysis/gluconeogenesis, amino acid and fatty acid metabolism were downregulated. Immune cell typing highlighted the inflammatory response of innate immune cells headed by neutrophils. The reliability of RNA sequencing results were verified with selected differentially expressed genes by real-time PCR. This work provides an insight into the pathogenesis of lethal A. baumannii lung infection.
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Affiliation(s)
- Xi Zeng
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Army Medical University, Chongqing, China
| | - Hao Gu
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Army Medical University, Chongqing, China.,Institute of Biopharmaceutical Research, West China Hospital, Sichuan University, Chengdu, China.,Department of Clinical Laboratory, 971st Hospital of People's Liberation Army, Qingdao, China
| | - Liusheng Peng
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Army Medical University, Chongqing, China
| | - Yao Yang
- Institute of Materia Medica, College of Pharmacy, Army Medical University, Chongqing, China
| | - Ning Wang
- Institute of Biopharmaceutical Research, West China Hospital, Sichuan University, Chengdu, China
| | - Yun Shi
- Institute of Biopharmaceutical Research, West China Hospital, Sichuan University, Chengdu, China
| | - Quanming Zou
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Army Medical University, Chongqing, China
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9
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Cafiso V, Stracquadanio S, Lo Verde F, Dovere V, Zega A, Pigola G, Aranda J, Stefani S. COL R Acinetobacter baumannii sRNA Signatures: Computational Comparative Identification and Biological Targets. Front Microbiol 2020; 10:3075. [PMID: 32010115 PMCID: PMC6978653 DOI: 10.3389/fmicb.2019.03075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 12/19/2019] [Indexed: 11/25/2022] Open
Abstract
Multidrug-Resistant (MDR) and Extensively Drug Resistant (XDR) Acinetobacter baumannii (Ab) represent a serious cause of healthcare-associated infections worldwide. Currently, the available treatment options are very restricted and colistin-based therapies are last-line treatments of these infections, even though colistin resistant (COLR) Ab have rarely been isolated yet. In bacteria, small non-coding RNAs (sRNAs) have been implicated in regulatory pathways of different biological functions, however, no knowledge exists about the sRNA role on the biological adaptation in COLRAb. Our study investigated two Italian XDR isogenic colistin-susceptible/resistant (COLS/R) Ab strain-pairs to discover new sRNA signatures. Comparative sRNA transcriptome (sRNAome) analyses were carried out by Illumina RNA-seq using both a Tru-Seq and a Short Insert library, whilst Ab ATCC 17978 and ACICU Reference Genome assembly, mapping, annotation and statistically significant differential expression (q-value ≤ 0.01) of the raw reads were performed by the Rockhopper tool. A computational filtering, sorting only similarly statistically significant differentially expressed (DE) sRNAs mapping on the same gene in both COLRAb isolates was conducted. COLR vs. COLS sRNAome, analyzed integrating the DE sRNAs obtained from the two different libraries, revealed some statistically significant DE sRNAs in COLRAb. In detail, we found: (i) two different under-expressed cis-acting sRNAs (AbsRNA1 and AbsRNA2) mapping in antisense orientation the 16S rRNA gene A1S_r01, (ii) one under-expressed cis-acting sRNA (AbsRNA3) targeting the A1S_2505 gene (hypothetical protein), (iii) one under-expressed microRNA-size small RNA fragment (AbsRNA4) and its pre-microAbsRNA4 targeting the A1S_0501 gene (hypothetical protein), (iv) as well as an over-expressed microRNA-size small RNA fragment (AbsRNA5) and its pre-microAbsRNA5 targeting the A1S_3097 gene (signal peptide). Custom TaqMan® probe-based real-time qPCRs validated the expression pattern of the selected sRNA candidates shown by RNA-seq. Furthermore, analysis on sRNA ΔA1S_r01, ΔA1S_2505 as well as the over-expressed A1S_3097 mutants revealed no effects on colistin resistance. Our study, for the first time, found the sRNAome signatures of clinical COLRAb with a computational prediction of their targets related to protein synthesis, host-microbe interaction and other different biological functions, including biofilm production, cell-cycle control, virulence, and antibiotic-resistance.
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Affiliation(s)
- Viviana Cafiso
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Stefano Stracquadanio
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Flavia Lo Verde
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Veronica Dovere
- Department of Translational Research and New Technology in Medicine and Surgery, Azienda Ospedaliero Universitaria Pisana, University of Pisa, Pisa, Italy
| | - Alessandra Zega
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Giuseppe Pigola
- Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Jesús Aranda
- Departament de Genètica i Microbiologia, Facultat de Biociènces, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Stefania Stefani
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
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10
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Chen Y, Shao T, Fang S, Pan P, Jiang J, Cheng T, Wan H, Yu D. Effect of calcium on the interaction of Acinetobacter baumannii with human respiratory epithelial cells. BMC Microbiol 2019; 19:264. [PMID: 31771504 PMCID: PMC6880639 DOI: 10.1186/s12866-019-1643-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 11/14/2019] [Indexed: 02/07/2023] Open
Abstract
Background Investigating the factors that influence Acinetobacter baumannii(Ab) adhesion/invasion of host cells is important to understand its pathogenicity. Metal cations have been shown to play an important role in regulating the biofilm formation and increasing the virulence of Ab; however, the effect of calcium on host-bacterial interaction has yet to be clarified. Here, the dynamic process of the interaction between Ab and human respiratory epithelial cells and the effect of calcium on host-bacterial interaction were explored using microscopic imaging, quantitative PCR and real time cellular analysis (RTCA). Results The concentration of calcium, multiplicity of infection and co-culture time were all demonstrated to have effects on host-bacterial interaction. A unique “double peak” phenomenon changed to a sharp “single peak” phenomenon during the process of Ab infection under the effect of calcium was observed in the time-dependent cell response profiles. Moreover, calcium can increase Ab adhesion/invasion of epithelial cells by regulating the expression of Ab-related genes (ompA, bfmRS, abaI). Conclusions Effective control of calcium concentrations can provide new approaches for the prevention and treatment of multi-drug resistant Ab.
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Affiliation(s)
- Yi Chen
- Hangzhou First People's Hospital, Zhejiang Chinese Medical University, Hangzhou, China.,Department of Clinical Laboratory, Zhejiang Hospital, Hangzhou, China
| | - Tingjun Shao
- Hangzhou First People's Hospital, Zhejiang Chinese Medical University, Hangzhou, China
| | - Sanhua Fang
- Zhejiang University School of Medicine, Hangzhou, China
| | - Ping Pan
- Hangzhou First People's Hospital, Zhejiang Chinese Medical University, Hangzhou, China
| | - Jiahui Jiang
- Hangzhou First People's Hospital, Zhejiang Chinese Medical University, Hangzhou, China
| | - Tongtong Cheng
- Hangzhou First People's Hospital, Zhejiang Chinese Medical University, Hangzhou, China
| | - Haitong Wan
- Zhejiang Chinese Medical University, Hangzhou, China
| | - Daojun Yu
- Hangzhou First People's Hospital, Zhejiang Chinese Medical University, Hangzhou, China. .,Zhejiang University School of Medicine, Hangzhou, China. .,Zhejiang Chinese Medical University, Hangzhou, China.
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11
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Correlation of Virulence Factors and Cell Adhesion of Clinical Isolates of Acinetobacter baumannii. ARCHIVES OF CLINICAL INFECTIOUS DISEASES 2018. [DOI: 10.5812/archcid.62841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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12
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Abdollahi S, Rasooli I, Mousavi Gargari SL. The role of TonB-dependent copper receptor in virulence of Acinetobacter baumannii. INFECTION GENETICS AND EVOLUTION 2018; 60:181-190. [PMID: 29505819 DOI: 10.1016/j.meegid.2018.03.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 02/11/2018] [Accepted: 03/01/2018] [Indexed: 12/15/2022]
Abstract
Acinetobacter baumannii is an opportunistic gram negative pathogen that can adhere to different surfaces and cause different nosocomial infections. To investigate the role of TonB-dependent copper receptor, an outer membrane protein, in virulence of A. baumannii, we deleted this receptor from A. baumannii chromosome. There was a significant decrease in biofilm formation by copper receptor deficient mutant strain. Similarly, the adherence to human epithelial cell and the hydrophobicity were declined. The survival rate of the mutant strain in human sera was reduced while no change was observed in motility of strains. In murine pneumonia model, the bacterial lethal dose 0 (LD0), LD50 and LD100 were increased for mutant strain. Moreover, in vivo and in vitro experiments revealed changes in growth rate and dissemination of mutant strain; so that the bacterial load of the mutant was significantly reduced in the spleen and lung. The findings suggest a critical role for TonB-dependent copper receptor in virulence of A. baumannii.
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Affiliation(s)
| | - Iraj Rasooli
- Department of Biology, Shahed University, Tehran, Iran; Molecular Microbiology Research Center, Shahed University, Tehran, Iran.
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13
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Dikshit N, Kale SD, Khameneh HJ, Balamuralidhar V, Tang CY, Kumar P, Lim TP, Tan TT, Kwa AL, Mortellaro A, Sukumaran B. NLRP3 inflammasome pathway has a critical role in the host immunity against clinically relevant Acinetobacter baumannii pulmonary infection. Mucosal Immunol 2018; 11:257-272. [PMID: 28612844 DOI: 10.1038/mi.2017.50] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Accepted: 04/15/2017] [Indexed: 02/04/2023]
Abstract
The opportunistic Gram-negative bacterium Acinetobacter baumannii (AB) is a leading cause of life-threatening nosocomial pneumonia. Outbreaks of multidrug resistant (MDR)-AB belonging to international clones (ICs) I and II with limited treatment options are major global health threats. However, the pathogenesis mechanisms of various AB clonal groups are understudied. Although inflammation-associated interleukin-1β (IL-1β) levels and IL-1 receptor antagonist polymorphisms were previously implicated in MDR-AB-related pneumonia in patients, whether inflammasomes has any role in the host defense and/or pathogenesis of clinically relevant A. baumannii infection is unknown. Using a sublethal mouse pneumonia model, we demonstrate that an extensively drug-resistant clinical isolate (ICII) of A. baumannii exhibits reduced/delayed early pulmonary neutrophil recruitment, higher lung persistence, and, most importantly, elicits enhanced IL-1β/IL-18 production and lung damage through NLRP3 inflammasome, in comparison with A. baumannii-type strain. A. baumannii infection-induced IL-1β/IL-18 production is entirely dependent on NLRP3-ASC-caspase-1/caspase-11 pathway. Using Nlrp3-/- mice infection models, we further show that while NLRP3 inflammasome pathway contributes to host defense against A. baumannii clinical isolate, it is dispensable for protection against A. baumannii-type strain. Our study reveals a novel differential role for NLRP3 inflammasome pathway in the immunity against clinically relevant A. baumannii infections, and highlights inflammasome pathway as a potential immunomodulatory target.
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Affiliation(s)
- N Dikshit
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - S D Kale
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - H J Khameneh
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - V Balamuralidhar
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - C Y Tang
- Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - P Kumar
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - T P Lim
- Department of Pharmacy, Singapore General Hospital, Singapore.,Sing Health Duke-NUS Medicine Academic Clinical Programme (MED ACP), Singapore, Singapore
| | - T T Tan
- Department of Infectious Diseases, Singapore General Hospital, Singapore, Singapore
| | - A L Kwa
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore.,Department of Pharmacy, Singapore General Hospital, Singapore.,Sing Health Duke-NUS Medicine Academic Clinical Programme (MED ACP), Singapore, Singapore.,Department of Pharmacy, National University of Singapore, Singapore, Singapore
| | - A Mortellaro
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - B Sukumaran
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
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14
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Kale SD, Dikshit N, Kumar P, Balamuralidhar V, Khameneh HJ, Bin Abdul Malik N, Koh TH, Tan GGY, Tan TT, Mortellaro A, Sukumaran B. Nod2 is required for the early innate immune clearance of Acinetobacter baumannii from the lungs. Sci Rep 2017; 7:17429. [PMID: 29234083 PMCID: PMC5727160 DOI: 10.1038/s41598-017-17653-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 11/19/2017] [Indexed: 12/19/2022] Open
Abstract
Acinetobacter baumannii (A. baumannii) is a significant cause of severe nosocomial pneumonia in immunocompromised individuals world-wide. With limited treatment options available, a better understanding of host immnity to A. baumannii infection is critical to devise alternative control strategies. Our previous study has identified that intracellular Nod1/Nod2 signaling pathway is required for the immune control of A. baumannii in airway epithelial cells in vitro. In the current study, using Nod2−/− mice and an in vivo sublethal model of pulmonary infection, we show that Nod2 contributes to the early lung defense against A. baumannii infection through reactive oxygen species (ROS)/reactive nitrogen species (RNS) production as Nod2−/− mice showed significantly reduced production of ROS/RNS in the lungs following A. baumannii infection. Consistent with the higher bacterial load, A. baumannii-induced neutrophil recruitment, cytokine/chemokine response and lung pathology was also exacerbated in Nod2−/− mice at early time points post-infection. Finally, we show that administration of Nod2 ligand muramyl dipeptide (MDP) prior to infection protected the wild- type mice from A. baumannii pulmonary challenge. Collectively, Nod2 is an important player in the early lung immunity against A. baumannii and modulating Nod2 pathway could be considered as a viable therapeutic strategy to control A. baumannii pulmonary infection.
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Affiliation(s)
- Sandeep D Kale
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, 169857, Singapore
| | - Neha Dikshit
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, 169857, Singapore
| | - Pankaj Kumar
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, 169857, Singapore
| | | | - Hanif Javanmard Khameneh
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore, 138648, Singapore
| | - Najib Bin Abdul Malik
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, 169857, Singapore
| | - Tse Hsien Koh
- Department of Microbiology, Division of Pathology, Singapore General Hospital, Singapore, Singapore
| | | | - Thuan Tong Tan
- Department of Infectious Diseases, Singapore General Hospital, Singapore, Singapore
| | - Alessandra Mortellaro
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore, 138648, Singapore
| | - Bindu Sukumaran
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, 169857, Singapore.
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15
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Ambrosi C, Scribano D, Aleandri M, Zagaglia C, Di Francesco L, Putignani L, Palamara AT. Acinetobacter baumannii Virulence Traits: A Comparative Study of a Novel Sequence Type with Other Italian Endemic International Clones. Front Microbiol 2017; 8:1977. [PMID: 29075243 PMCID: PMC5643476 DOI: 10.3389/fmicb.2017.01977] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 09/25/2017] [Indexed: 01/20/2023] Open
Abstract
Carbapenem-resistant Acinetobacter baumannii (CRAb) have emerged in recent decades as major causes of nosocomial infections. Resistance is mainly due to overexpression of intrinsic and/or acquired carbapenemases, especially oxacillinases (OXA). In Italy, although the sequence type (ST) 2 and the ST78 are the most frequently detected, we recently reported ST632, a single locus variant of ST2. Therefore, this study was aimed at unraveling common bacterial surface virulence factors involved in pathogenesis and antibiotic resistance in representative CRAb of these ST genotypes. Outer membrane protein (OMP) composition together with motility, biofilm formation, in vitro adherence to, invasion of, and survival within pneumocytes were analyzed. Differently from the carbapenem-susceptible reference strain ATCC 17978, either overexpressed OXA-51 or both OXA-23 and OXA-51 co-purified with OMPs in CRAb. This tight association ensures their maximal concentration on the inner surface of the outer membrane to provide the best protection against carbapenems. These findings led us to propose for the first time a common behavior of OXA enzymes in CRAb. Despite the presence of both OmpA and phosphorylcholine-porinD and the ability of all the strains to adhere to cells, invasion, and survival within pneumocytes was shown only by ST2 and ST78 isolates, sharing the highest number of identified OMPs. Conversely, notwithstanding genetic and OMPs similarities with ST2, ST632 was unable to invade and survive within epithelial cells. Overall, our study shows that different STs share a specific OMP composition, also shaped by overexpressed OXA, that is needed for invasiveness and survival of CRAb.
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Affiliation(s)
- Cecilia Ambrosi
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.,Dani Di Giò Foundation-Onlus, Rome, Italy
| | - Daniela Scribano
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.,Department of Medical, Oral and Biotechnological Sciences, Università degli Studi "G. d'Annunzio" Chieti-Pescara, Chieti, Italy
| | - Marta Aleandri
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Carlo Zagaglia
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Laura Di Francesco
- Unit of Human Microbiome, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Lorenza Putignani
- Unit of Human Microbiome, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.,Unit of Parasitology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Anna Teresa Palamara
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Laboratory Affiliated to Institute Pasteur Italia, Cenci-Bolognetti Foundation, Rome, Italy.,San Raffaele Pisana, IRCCS, Telematic University, Rome, Italy
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16
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Immunoprotective potential of BamA, the outer membrane protein assembly factor, against MDR Acinetobacter baumannii. Sci Rep 2017; 7:12411. [PMID: 28963492 PMCID: PMC5622086 DOI: 10.1038/s41598-017-12789-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 09/19/2017] [Indexed: 12/19/2022] Open
Abstract
Acinetobacter baumannii infections are responsible for major health problems in immunocompromised patients particularly in intensive care units. Due to rapid acquisition of and also inherent drug resistance, a vaccine is an effective treatment option against this pathogen. BamA, an outer membrane β-barrel assembly protein, was identified in A. baumannii as potential vaccine candidate by in silico analysis. The immunoprotective efficacy of this highly conserved protein was investigated against a virulent multidrug resistant clinical isolate using murine pneumonia model. Recombinant BamA elicited a high IgG antibody titer (160000) in mice. Opsonophagocytic killing assay showed non-neutrilizing, opsonizing antibodies with combinatorial bactericidal activity of antibodies and complement components. Active and passive immunization protected 80 and 60% mice respectively against intranasal challenge with lethal dose (109 CFU) of virulent A. baumannii along with efficient clearance of bacteria in mice lungs and reduction in levels of pro-inflammatory cytokines viz. TNF-α, IL-6 and IL-1β in sera and lung tissue homogenate. Increase in levels of IL-10, an anti-inflammatory cytokine and reduction of neutrophils in lungs facilitated the control of infection. This study demonstrates the potential of BamA as effective vaccine candidate and a promising target for antibody-based therapy to protect against MDR A. baumannii infections.
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17
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Tiwari V, Tiwari M, Solanki V. Polyvinylpyrrolidone-Capped Silver Nanoparticle Inhibits Infection of Carbapenem-Resistant Strain of Acinetobacter baumannii in the Human Pulmonary Epithelial Cell. Front Immunol 2017; 8:973. [PMID: 28861082 PMCID: PMC5561010 DOI: 10.3389/fimmu.2017.00973] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 07/31/2017] [Indexed: 11/13/2022] Open
Abstract
Acinetobacter baumannii, an opportunistic ESKAPE pathogen, causes respiratory and urinary tract infections. Its prevalence increases gradually in the clinical setup. Pathogenicity of Acinetobacter is significantly influenced by its ability to infect and survive in human pulmonary cells. Therefore, it is important to study the infection of A. baumannii in human pulmonary host cell (A-549), monitoring surface interacting and internalized bacteria. It was found that during infection of A. baumannii, about 40% bacteria adhered to A-549, whereas 20% got internalized inside pulmonary cell and induces threefold increase in the reactive oxygen species production. We have synthesized polyvinylpyrrolidone (PVP)-capped AgNPs using chemical methods and tested its efficacy against carbapenem-resistant strain of A. baumannii. PVP-capped silver nanoparticles (PVP-AgNPs) (30 µM) have shown antibacterial activity against carbapenem-resistant strain of A. baumannii and this concentration does not have any cytotoxic effect on the human pulmonary cell line (IC50 is 130 µM). Similarly, PVP-AgNPs treatment decreases 80% viability of intracellular bacteria, decreases adherence of A. baumannii to A-549 (40 to 2.2%), and decreases intracellular concentration (20 to 1.3%) of A. baumannii. This concludes that PVP-AgNPs can be developed as a substitute for carbapenem to control the infection caused by carbapenem-resistant A. baumannii.
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Affiliation(s)
- Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
| | - Vandana Solanki
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
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18
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Rosales-Reyes R, Gayosso-Vázquez C, Fernández-Vázquez JL, Jarillo-Quijada MD, Rivera-Benítez C, Santos-Preciado JI, Alcántar-Curiel MD. Virulence profiles and innate immune responses against highly lethal, multidrug-resistant nosocomial isolates of Acinetobacter baumannii from a tertiary care hospital in Mexico. PLoS One 2017; 12:e0182899. [PMID: 28797068 PMCID: PMC5552319 DOI: 10.1371/journal.pone.0182899] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 07/26/2017] [Indexed: 11/18/2022] Open
Abstract
Virulence profiles and innate immune responses were studied in Acinetobacter baumannii from nosocomial infections collected over one year in a tertiary care hospital in Mexico. A. baumannii were identified by VITEK 2 System followed by susceptibility tests. Carbapenemase genes, active efflux mechanism to imipenem and meropenem and outer membrane proteins profile were analyzed to evaluate their role on the activity of carbapenem resistance. All isolates were genotyped by pulsed field gel electrophoresis. The ability to form biofilm was determined on a polystyrene surface. The resistance to complement was determined with a pooled human normal serum and TNFα release by infected macrophages was determined by ELISA. The 112 isolates from this study were associated with a 52% of mortality. All were resistance to β-lactams, fluoroquinolones, and trimethroprim-sulfamethoxal, 96 and 90% were resistant to meropenem and imipenem, respectively, but with high susceptibility to polymyxin B, colistin and tigecyclin. Isolates were classified in 11 different clones. Most isolates, 88% (99/112), were metallo-β-lactamases and carbapenemases producers, associated in 95% with the presence of blaOXA-72 gene. Only 4/99 and 1/99 of the carbapenem-resistant isolates were related to efflux mechanism to meropenem or imipenem resistance, respectively. The loss of expression of 22, 29, and/or 33-36-kDa proteins was detected in 8/11 of the clinical isolates with resistance to carbapenem. More than 96% (108/112) of the isolates were high producers of biofilms on biotic surfaces. Finally, all isolates showed variable resistance to normal human serum activity and were high inductors of TNFα release by macrophages. In summary, these results suggest that multidrug-resistant A. baumannii can persist in the hospital environment through its ability to form biofilms. The high mortality observed was due to their ability to survive normal human serum activity and capability to induce potent inflammatory immune response making this nosocomial pathogen a serious threat to hospitalized patients.
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Affiliation(s)
- Roberto Rosales-Reyes
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México. Ciudad de México, México
- * E-mail: (MDAC); (RRR)
| | - Catalina Gayosso-Vázquez
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México. Ciudad de México, México
| | - José Luis Fernández-Vázquez
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México. Ciudad de México, México
| | - Ma Dolores Jarillo-Quijada
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México. Ciudad de México, México
| | | | - José Ignacio Santos-Preciado
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México. Ciudad de México, México
| | - María Dolores Alcántar-Curiel
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México. Ciudad de México, México
- * E-mail: (MDAC); (RRR)
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19
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Sato Y, Unno Y, Kawakami S, Ubagai T, Ono Y. Virulence characteristics of Acinetobacter baumannii clinical isolates vary with the expression levels of omps. J Med Microbiol 2017; 66:203-212. [PMID: 27902395 DOI: 10.1099/jmm.0.000394] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
PURPOSE We investigated the expression levels of virulence factors (ompA, omp33-36 and carO) in five clinical isolates and in a standard ATCC 19606 strain of Acinetobacter baumannii to determine their effect on the virulence characteristics of the isolates. METHODOLOGY The mRNA levels of omps and proinflammatory cytokines were analyzed by quantitative real-time PCR. For adherence assay, after human lung epithelial cells (A549) were co-cultured with A. baumannii at 37 °C for 2 h, the cell-adherent bacteria was counted. Pearson correlation analysis was used to compare the omps mRNA levels, the proinflammatory cytokines and the number of adherent bacteria. RESULTS The mRNA levels of ompA in the clinical isolates were higher and similar compared with those in ATCC 19606, whereas the mRNA levels of omp33-36 in the clinical isolates were lower and similar compared with those in ATCC 19606. The mRNA levels of carO in the clinical isolates were significantly higher than those in ATCC 19606. The number of cell-adherent clinical isolates was higher than that of cell-adherent ATCC 19606. Furthermore, the number of cell-adherent clinical isolates was positively and significantly correlated with ompA mRNA level. The mRNA levels of TNF-α, IL-6 and IL-8 in A549 cells co-cultured with the clinical isolates were lower than those in A549 cells co-cultured with ATCC 19606. Moreover, the mRNA levels of TNF-α, IL-6 and IL-8 were negatively and significantly correlated with those of carO in the isolates. CONCLUSION These results provide insights into the renewed virulence characteristics of A. baumannii clinical isolates that depend on cell adherence capacity and the expression level of omp mRNAs.
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Affiliation(s)
- Yoshinori Sato
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Yuka Unno
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Sayoko Kawakami
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Tsuneyuki Ubagai
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Yasuo Ono
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
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20
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Ji J, Su L, Liu Z. Critical role of calpain in inflammation. Biomed Rep 2016; 5:647-652. [PMID: 28101338 DOI: 10.3892/br.2016.785] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 09/14/2016] [Indexed: 02/07/2023] Open
Abstract
Calpains are a family of cysteine proteases, implicated in a wide range of cellular calcium-regulated functions. Evidence from previous studies using an inhibitor of calpain indicates that calpain activation is involved in the process of numerous inflammation-associated diseases. As a result of in-depth studies, calpains have been proposed to influence the process of inflammation via a variety of mechanisms. The aim of the present study is to provide an overview of recent reports regarding the role of calpain in the process of inflammation, including regulation of immune cell migration, modulation of the activation of inflammatory mediators, degradation of certain associated proteins and induction of cell apoptosis. Understanding these mechanisms may contribute to the investigation of novel therapeutic targets for inflammation-associated diseases.
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Affiliation(s)
- Jingjing Ji
- Department of Critical Care Medicine, General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China; Graduate School, Guangzhou Medical University, Guangzhou, Guangdong 510010, P.R. China
| | - Lei Su
- Department of Critical Care Medicine, General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China; Key Laboratory of Hot Zone Trauma Care and Tissue Repair of PLA, General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China
| | - Zhifeng Liu
- Department of Critical Care Medicine, General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China; Key Laboratory of Hot Zone Trauma Care and Tissue Repair of PLA, General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China
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21
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Wan G, Ruan L, Yin Y, Yang T, Ge M, Cheng X. Effects of silver nanoparticles in combination with antibiotics on the resistant bacteria Acinetobacter baumannii. Int J Nanomedicine 2016; 11:3789-800. [PMID: 27574420 PMCID: PMC4990392 DOI: 10.2147/ijn.s104166] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Acinetobacter baumannii resistance to carbapenem antibiotics is a serious clinical challenge. As a newly developed technology, silver nanoparticles (AgNPs) show some excellent characteristics compared to older treatments, and are a candidate for combating A. baumannii infection. However, its mechanism of action remains unclear. In this study, we combined AgNPs with antibiotics to treat carbapenem-resistant A. baumannii (aba1604). Our results showed that single AgNPs completely inhibited A. baumannii growth at 2.5 μg/mL. AgNP treatment also showed synergistic effects with the antibiotics polymixin B and rifampicin, and an additive effect with tigecyline. In vivo, we found that AgNPs-antibiotic combinations led to better survival ratios in A. baumannii-infected mouse peritonitis models than that by single drug treatment. Finally, we employed different antisense RNA-targeted Escherichia coli strains to elucidate the synergistic mechanism involved in bacterial responses to AgNPs and antibiotics.
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Affiliation(s)
- Guoqing Wan
- School of Life Science and Technology, China Pharmaceutical University, Nanjing; Shanghai Laiyi Center for Biopharmaceutical R&D
| | - Lingao Ruan
- Shanghai Laiyi Center for Biopharmaceutical R&D; School of Pharmacy, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Yu Yin
- Shanghai Laiyi Center for Biopharmaceutical R&D; School of Pharmacy, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Tian Yang
- Shanghai Laiyi Center for Biopharmaceutical R&D; School of Pharmacy, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Mei Ge
- Shanghai Laiyi Center for Biopharmaceutical R&D
| | - Xiaodong Cheng
- School of Life Science and Technology, China Pharmaceutical University, Nanjing; Department of Integrative Biology & Pharmacology, The University of Texas Health Science Center, Houston, TX, USA
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Efficacy of Lysophosphatidylcholine in Combination with Antimicrobial Agents against Acinetobacter baumannii in Experimental Murine Peritoneal Sepsis and Pneumonia Models. Antimicrob Agents Chemother 2016; 60:4464-70. [PMID: 27161639 DOI: 10.1128/aac.02708-15] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 04/28/2016] [Indexed: 11/20/2022] Open
Abstract
Immune response stimulation to prevent infection progression may be an adjuvant to antimicrobial treatment. Lysophosphatidylcholine (LPC) is an immunomodulator involved in immune cell recruitment and activation. In this study, we aimed to evaluate the efficacy of LPC in combination with colistin, tigecycline, or imipenem in experimental murine models of peritoneal sepsis and pneumonia. We used Acinetobacter baumannii strain Ab9, which is susceptible to colistin, tigecycline, and imipenem, and multidrug-resistant strain Ab186, which is susceptible to colistin and resistant to tigecycline and imipenem. Pharmacokinetic and pharmacodynamic parameters for colistin, tigecycline, and imipenem and the 100% minimal lethal dose (MLD100) were determined for both strains. The therapeutic efficacies of LPC, colistin (60 mg/kg of body weight/day), tigecycline (10 mg/kg/day), and imipenem (180 mg/kg/day), alone or in combination, were assessed against Ab9 and Ab186 at the MLD100 in murine peritoneal sepsis and pneumonia models. The levels of pro- and anti-inflammatory cytokines, i.e., tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10), were determined by enzyme-linked immunosorbent assay (ELISA) for the same experimental models after inoculating mice with the MLD of both strains. LPC in combination with colistin, tigecycline, or imipenem markedly enhanced the bacterial clearance of Ab9 and Ab186 from the spleen and lungs and reduced bacteremia and mouse mortality rates (P < 0.05) compared with those for colistin, tigecycline, and imipenem monotherapies. Moreover, at 4 h post-bacterial infection, Ab9 induced higher TNF-α and lower IL-10 levels than those with Ab186 (4 μg/ml versus 3 μg/ml [P < 0.05] and 2 μg/ml versus 3.4 μg/ml [P < 0.05], respectively). LPC treatment combined with colistin, tigecycline, or imipenem modestly reduced the severity of infection by A. baumannii strains with different resistance phenotypes compared to LPC monotherapy in both experimental models.
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Singh R, Garg N, Shukla G, Capalash N, Sharma P. Immunoprotective Efficacy of Acinetobacter baumannii Outer Membrane Protein, FilF, Predicted In silico as a Potential Vaccine Candidate. Front Microbiol 2016; 7:158. [PMID: 26904021 PMCID: PMC4751259 DOI: 10.3389/fmicb.2016.00158] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 01/29/2016] [Indexed: 11/22/2022] Open
Abstract
Acinetobacter baumannii is emerging as a serious nosocomial pathogen with multidrug resistance that has made it difficult to cure and development of efficacious treatment against this pathogen is direly needed. This has led to investigate vaccine approach to prevent and treat A. baumannii infections. In this work, an outer membrane putative pilus assembly protein, FilF, was predicted as vaccine candidate by in silico analysis of A. baumannii proteome and was found to be conserved among the A. baumannii strains. It was cloned and expressed in E. coli BL21(DE3) and purified by Ni-NTA chromatography. Immunization with FilF generated high antibody titer (>64,000) and provided 50% protection against a standardized lethal dose (108 CFU) of A. baumannii in murine pneumonia model. FilF immunization reduced the bacterial load in lungs by 2 and 4 log cycles, 12 and 24 h post infection as compared to adjuvant control; reduced the levels of pro-inflammatory cytokines TNF-α, IL-6, IL-33, IFN-γ, and IL-1β significantly and histology of lung tissue supported the data by showing considerably reduced damage and infiltration of neutrophils in lungs. These results demonstrate the in vivo validation of immunoprotective efficacy of a protein predicted as a vaccine candidate by in silico proteomic analysis and open the possibilities for exploration of a large array of uncharacterized proteins.
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Affiliation(s)
- Ravinder Singh
- Department of Microbiology, Panjab University Chandigarh, India
| | - Nisha Garg
- Department of Microbiology, Panjab University Chandigarh, India
| | - Geeta Shukla
- Department of Microbiology, Panjab University Chandigarh, India
| | - Neena Capalash
- Department of Biotechnology, Panjab University Chandigarh, India
| | - Prince Sharma
- Department of Microbiology, Panjab University Chandigarh, India
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Therapeutic efficacy of lysophosphatidylcholine in severe infections caused by Acinetobacter baumannii. Antimicrob Agents Chemother 2015; 59:3920-4. [PMID: 25896698 DOI: 10.1128/aac.04986-14] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 04/12/2015] [Indexed: 01/13/2023] Open
Abstract
Due to the significant increase in antimicrobial resistance of Acinetobacter baumannii, immune system stimulation to block infection progression may be a therapeutic adjuvant to antimicrobial treatment. Lysophosphatidylcholine (LPC), a major component of phospholipids in eukaryotic cells, is involved in immune cell recruitment and modulation. The aim of this study was to show if LPC could be useful for treating infections caused by A. baumannii. A. baumannii ATCC 17978 was used in this study. Levels of serum LPC and levels of the inflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), IL-1β, and IL-10 were determined by spectrophotometric assay and enzyme-linked immunosorbent assay (ELISA), respectively, using a murine peritoneal sepsis model in which mice were inoculated with 5.3 log CFU/ml of A. baumannii. The therapeutic efficacy of LPC against A. baumannii in murine peritoneal sepsis and pneumonia models was assessed for 48 h after bacterial infection. At early time points in the murine model of peritoneal sepsis caused by A. baumannii, LPC was depleted and was associated with an increase of inflammatory cytokine release. Preemptive therapy with LPC in murine peritoneal sepsis and pneumonia models markedly enhanced spleen and lung bacterial clearance and reduced the numbers of positive blood cultures and the mouse mortality rates. Moreover, treatment with LPC reduced proinflammatory cytokine production. These data demonstrate that LPC is efficacious as a preemptive treatment in experimental models of peritoneal sepsis and pneumonia caused by A. baumannii.
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The Acinetobacter baumannii Omp33-36 porin is a virulence factor that induces apoptosis and modulates autophagy in human cells. Infect Immun 2014; 82:4666-80. [PMID: 25156738 DOI: 10.1128/iai.02034-14] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Acinetobacter baumannii is an extracellular opportunistic human pathogen that is becoming increasingly problematic in hospitals. In the present study, we demonstrate that the A. baumannii Omp 33- to 36-kDa protein (Omp33-36) is a porin that acts as a channel for the passage of water. The protein is found on the cell surface and is released along with other porins in the outer membrane vesicles (OMVs). In immune and connective cell tissue, this protein induced apoptosis by activation of caspases and modulation of autophagy, with the consequent accumulation of p62/SQSTM1 (sequestosome 1) and LC3B-II (confirmed by use of autophagy inhibitors). Blockage of autophagy enables the bacterium to persist intracellularly (inside autophagosomes), with the subsequent development of cytotoxicity. Finally, we used macrophages and a mouse model of systemic infection to confirm that Omp33-36 is a virulence factor in A. baumannii. Overall, the study findings show that Omp33-36 plays an important role in the pathogenesis of A. baumannii infections.
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Li N, Yin L, Thévenin D, Yamada Y, Limmon G, Chen J, Chow VT, Engelman DM, Engelward BP. Peptide targeting and imaging of damaged lung tissue in influenza-infected mice. Future Microbiol 2013; 8:257-69. [PMID: 23374130 DOI: 10.2217/fmb.12.134] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
AIM In this study, we investigate whether pH (low) insertion peptide (pHLIP) can target regions of lung injury associated with influenza infection. MATERIALS & METHODS Fluorophore-conjugated pHLIP was injected intraperitoneally into mice infected with a sublethal dose of H1N1 influenza and visualized histologically. RESULTS pHLIP specifically targeted inflamed lung tissues of infected mice in the later stages of disease and at sites where alveolar type I and type II cells were depleted. Regions of pHLIP-targeted lung tissue were devoid of peroxiredoxin 6, the lung-abundant antioxidant enzyme, and were deficient in pneumocytes. Interestingly, a pHLIP variant possessing mutations that render it insensitive to pH changes was also able to target damaged lung tissue. CONCLUSION pHLIP holds potential for delivering therapeutics for lung injury during influenza infection. Furthermore, there may be more than one mechanism that enables pHLIP variants to target inflamed lung tissue.
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Affiliation(s)
- Na Li
- Interdisciplinary Research Group in Infectious Diseases, Singapore-Massachusetts Institute of Technology Alliance in Research & Technology, 1 CREATE Way, #03-12/13/14 Enterprise Wing, 138602, Singapore
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Mortensen BL, Skaar EP. Host-microbe interactions that shape the pathogenesis of Acinetobacter baumannii infection. Cell Microbiol 2012; 14:1336-44. [PMID: 22640368 DOI: 10.1111/j.1462-5822.2012.01817.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 05/15/2012] [Accepted: 05/21/2012] [Indexed: 12/24/2022]
Abstract
Acinetobacter baumannii is an opportunistic pathogen that has emerged as a prevalent source of nosocomial infections, most frequently causing ventilator-associated pneumonia. The emergence of pan-drug resistant strains magnifies the problem by reducing viable treatment options and effectively increasing the mortality rate associated with Acinetobacter infections. In light of this rising threat, research on A. baumannii epidemiology, antibiotic resistance, and pathogenesis is accelerating. The recent development of both in vitro and in vivo models has enabled studies probing the host-Acinetobacter interface. Bacterial genetic screens and comparative genomic studies have led to the identification of several A. baumannii virulence factors. Additionally, investigations into host defence mechanisms using animal models or cell culture have provided insight into the innate immune response to infection. This review highlights some of the key attributes of A. baumannii virulence with an emphasis on bacterial interactions with the innate immune system.
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Affiliation(s)
- Brittany L Mortensen
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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28
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Smani Y, Docobo-Pérez F, López-Rojas R, Domínguez-Herrera J, Ibáñez-Martínez J, Pachón J. Platelet-activating factor receptor initiates contact of Acinetobacter baumannii expressing phosphorylcholine with host cells. J Biol Chem 2012; 287:26901-10. [PMID: 22689572 DOI: 10.1074/jbc.m112.344556] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Adhesion is an initial and important step in Acinetobacter baumannii causing infections. However, the exact molecular mechanism of such a step between A. baumannii and the host cells remains unclear. Here, we demonstrated that the phosphorylcholine (ChoP)-containing outer membrane protein of A. baumannii binds to A549 cells through platelet-activating factor receptor (PAFR), resulting in activation of G protein and intracellular calcium. Upon A. baumannii expressing ChoP binding to PAFR, clathrin and β-arrestins, proteins involved in the direction of the vacuolar movement, are activated during invasion of A. baumannii. PAFR antagonism restricts the dissemination of A. baumannii in the pneumonia model. These results define a role for PAFR in A. baumannii interaction with host cells and suggest a mechanism for the entry of A. baumannii into the cytoplasm of host cells.
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Affiliation(s)
- Younes Smani
- Clinic Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, 41013 Seville, Spain.
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Acinetobacter calcoaceticus-baumannii complex strains induce caspase-dependent and caspase-independent death of human epithelial cells. Curr Microbiol 2012; 65:319-29. [PMID: 22684803 PMCID: PMC3401494 DOI: 10.1007/s00284-012-0159-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 05/15/2012] [Indexed: 12/25/2022]
Abstract
We investigated interactions of human isolates of Acinetobacter calcoaceticus–baumannii complex strains with epithelial cells. The results showed that bacterial contact with the cells as well as adhesion and invasion were required for induction of cytotoxicity. The infected cells revealed hallmarks of apoptosis characterized by cell shrinking, condensed chromatin, and internucleosomal fragmentation of nuclear DNA. The highest apoptotic index was observed for 4 of 10 A.calcoaceticus and 4 of 7 A. baumannii strains. Moreover, we observed oncotic changes: cellular swelling and blebbing, noncondensed chromatin, and the absence of DNA fragmentation. The highest oncotic index was observed in cells infected with 6 A.calcoaceticus isolates. Cell-contact cytotoxicity and cell death were not inhibited by the pan-caspase inhibitor z-VAD-fmk. Induction of oncosis was correlated with increased invasive ability of the strains. We demonstrated that the mitochondria of infected cells undergo structural and functional alterations which can lead to cell death. Infected apoptotic and oncotic cells exhibited loss of mitochondrial transmembrane potential (ΔΨm). Bacterial infection caused generation of nitric oxide and reactive oxygen species. This study indicated that Acinetobacter spp. induced strain-dependent distinct types of epithelial cell death that may contribute to the pathogenesis of bacterial infection.
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30
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Smani Y, McConnell MJ, Pachón J. Role of fibronectin in the adhesion of Acinetobacter baumannii to host cells. PLoS One 2012; 7:e33073. [PMID: 22514602 PMCID: PMC3326023 DOI: 10.1371/journal.pone.0033073] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 02/09/2012] [Indexed: 11/29/2022] Open
Abstract
Adhesion to host cells is an initial and important step in Acinetobacter baumannii pathogenesis. However, there is relatively little information on the mechanisms by which A. baumannii binds to and interacts with host cells. Adherence to extracellular matrix proteins, such as fibronectin, affords pathogens with a mechanism to invade epithelial cells. Here, we found that A. baumannii adheres more avidly to immobilized fibronectin than to control protein. Free fibronectin used as a competitor resulted in dose-dependent decreased binding of A. baumannii to fibronectin. Three outer membrane preparations (OMPs) were identified as fibronectin binding proteins (FBPs): OMPA, TonB-dependent copper receptor, and 34 kDa OMP. Moreover, we demonstrated that fibronectin inhibition and neutralization by specific antibody prevented significantly the adhesion of A. baumannii to human lung epithelial cells (A549 cells). Similarly, A. baumannii OMPA neutralization by specific antibody decreased significantly the adhesion of A. baumannii to A549 cells. These data indicate that FBPs are key adhesins that mediate binding of A. baumannii to human lung epithelial cells through interaction with fibronectin on the surface of these host cells.
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Affiliation(s)
- Younes Smani
- Clinic Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville, IBiS, University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain.
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Qiu H, KuoLee R, Harris G, Zhou H, Miller H, Patel GB, Chen W. Acinetobacter baumannii infection inhibits airway eosinophilia and lung pathology in a mouse model of allergic asthma. PLoS One 2011; 6:e22004. [PMID: 21789200 PMCID: PMC3138758 DOI: 10.1371/journal.pone.0022004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 06/14/2011] [Indexed: 12/17/2022] Open
Abstract
Allergic asthma is a dysregulation of the immune system which leads to the development of Th2 responses to innocuous antigens (allergens). Some infections and microbial components can re-direct the immune response toward the Th1 response, or induce regulatory T cells to suppress the Th2 response, thereby inhibiting the development of allergic asthma. Since Acinetobacter baumannii infection can modulate lung cellular and cytokine responses, we studied the effect of A. baumannii in modulating airway eosinophilia in a mouse model of allergic asthma. Ovalbumin (OVA)-sensitized mice were treated with live A. baumannii or phosphate buffered saline (PBS), then intranasally challenged with OVA. Compared to PBS, A. baumannii treatment significantly reduced pulmonary Th2 cytokine and chemokine responses to OVA challenge. More importantly, the airway inflammation in A. baumannii-treated mice was strongly suppressed, as seen by the significant reduction of the proportion and the total number of eosinophils in the bronchoalveolar lavage fluid. In addition, A. baumannii-treated mice diminished lung mucus overproduction and pathology. However, A. baumannii treatment did not significantly alter systemic immune responses to OVA. Serum OVA-specific IgE, IgG1 and IgG2a levels were comparable between A. baumannii- and PBS-treated mice, and tracheobronchial lymph node cells from both treatment groups produced similar levels of Th1 and Th2 cytokines in response to in vitro OVA stimulation. Moreover, it appears that TLR-4 and IFN-γ were not directly involved in the A. baumannii-induced suppression of airway eosinophilia. Our results suggest that A. baumannii inhibits allergic airway inflammation by direct suppression of local pulmonary Th2 cytokine responses to the allergen.
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Affiliation(s)
- Hongyu Qiu
- Institute for Biological Sciences, National Research Council Canada, Ottawa, Ontario, Canada
| | - Rhonda KuoLee
- Institute for Biological Sciences, National Research Council Canada, Ottawa, Ontario, Canada
| | - Greg Harris
- Institute for Biological Sciences, National Research Council Canada, Ottawa, Ontario, Canada
| | - Hongyan Zhou
- Institute for Biological Sciences, National Research Council Canada, Ottawa, Ontario, Canada
| | - Harvey Miller
- Institute for Biological Sciences, National Research Council Canada, Ottawa, Ontario, Canada
| | - Girishchandra B. Patel
- Institute for Biological Sciences, National Research Council Canada, Ottawa, Ontario, Canada
| | - Wangxue Chen
- Institute for Biological Sciences, National Research Council Canada, Ottawa, Ontario, Canada
- Department of Biology, Brock University, St. Catharines, Ontario, Canada
- * E-mail:
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