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Ayibieke A, Wajima T, Kano S, Chatterjee NS, Hamabata T. The colonization factor CS6 of enterotoxigenic Escherichia coli contributes to host cell invasion. Microb Pathog 2024; 190:106636. [PMID: 38556103 DOI: 10.1016/j.micpath.2024.106636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 03/11/2024] [Accepted: 03/28/2024] [Indexed: 04/02/2024]
Abstract
Enterotoxigenic Escherichia coli (ETEC) is one of the main causes of diarrhea in children and travelers in low-income regions. The virulence of ETEC is attributed to its heat-labile and heat-stable enterotoxins, as well as its colonization factors (CFs). CFs are essential for ETEC adherence to the intestinal epithelium. However, its invasive capability remains unelucidated. In this study, we demonstrated that the CS6-positive ETEC strain 4266 can invade mammalian epithelial cells. The invasive capability was reduced in the 4266 ΔCS6 mutant but reintroduction of CS6 into this mutant restored the invasiveness. Additionally, the laboratory E. coli strain Top 10, which lacks the invasive capability, was able to invade Caco-2 cells after gaining the CS6-expressing plasmid pCS6. Cytochalasin D inhibited cell invasion in both 4266 and Top10 pCS6 cells, and F-actin accumulation was observed near the bacteria on the cell membrane, indicating that CS6-positive bacteria were internalized via actin polymerization. Other cell signal transduction inhibitors, such as genistein, wortmannin, LY294002, PP1, and Ro 32-0432, inhibited the CS6-mediated invasion of Caco-2 cells. The internalized bacteria of both 4266 and Top10 pCS6 strains were able to survive for up to 48 h, and 4266 cells were able to replicate within Caco-2 cells. Immunofluorescence microscopy revealed that the internalized 4266 cells were present in bacteria-containing vacuoles, which underwent a maturation process indicated by the recruitment of the early endosomal marker EEA-1 and late endosomal marker LAMP-1 throughout the infection process. The autophagy marker LC3 was also observed near these vacuoles, indicating the initiation of LC-3-associated phagocytosis (LAP). However, intracellular bacteria continued to replicate, even after the initiation of LAP. Moreover, intracellular filamentation was observed in 4266 cells at 24 h after infection. Overall, this study shows that CS6, in addition to being a major CF, mediates cell invasion. This demonstrates that once internalized, CS6-positive ETEC is capable of surviving and replicating within host cells. This capability may be a key factor in the extended and recurrent nature of ETEC infections in humans, thus highlighting the critical role of CS6.
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Affiliation(s)
- Alafate Ayibieke
- Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Takeaki Wajima
- Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan; Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Shigeyuki Kano
- Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan; Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | | | - Takashi Hamabata
- Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan; Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.
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Shen M, You Y, Xu C, Chen Z. Epigallocatechin-3-Gallate attenuates lipopolysacharide-induced pneumonia via modification of inflammation, oxidative stress, apoptosis, and autophagy. BMC Complement Med Ther 2024; 24:147. [PMID: 38580929 PMCID: PMC10996149 DOI: 10.1186/s12906-024-04436-y] [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: 01/10/2024] [Accepted: 03/14/2024] [Indexed: 04/07/2024] Open
Abstract
BACKGROUND Pneumonia, the acute inflammation of lung tissue, is multi-factorial in etiology. Hence, continuous studies are conducted to determine the mechanisms involved in the progression of the disease and subsequently suggest effective treatment. The present study attempted to evaluate the effects of Epigallocatechin-3-Gallate (EGCG), an herbal antioxidant, on inflammation, oxidative stress, apoptosis, and autophagy in a rat pneumonia model. METHODS Forty male Wistar rats, 5 months old and 250-290 g were divided into four groups including control, EGCG, experimental pneumonia (i/p LPS injection, 1 mg/kg), and experimental pneumonia treated with EGCG (i/p, 15 mg/kg, 1 h before and 3 h after LPS instillation). Total cell number in the bronchoalveolar lavage fluid, inflammation (TNF-a, Il-6, IL-1β, and NO), oxidative stress (Nrf2, HO-1, SOD, CAT, GSH, GPX, MDA, and TAC), apoptosis (BCL-2, BAX, CASP-3 and CASP-9), and autophagy (mTOR, LC3, BECN1) were evaluated. RESULTS The findings demonstrated that EGCG suppresses the LPS-induced activation of inflammatory pathways by a significant reduction of inflammatory markers (p-value < 0.001). In addition, the upregulation of BCL-2 and downregulation of BAX and caspases revealed that EGCG suppressed LPS-induced apoptosis. Furthermore, ECGC suppressed oxidative injury while promoting autophagy in rats with pneumonia (p-value < 0.05). CONCLUSION The current study revealed that EGCG could suppress inflammation, oxidative stress, apoptosis, and promote autophagy in experimental pneumonia models of rats suggesting promising therapeutical properties of this compound to be used in pneumonia management.
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Affiliation(s)
- Meili Shen
- Pediatric Critical Care Medicine Department, Quanzhou Children's Hospital (Quanzhou Maternal and Child Health Hospital), Fengze District, Quanzhou City, Fujian Province, 362000, China.
| | - Yuting You
- Children's Respiratory Department, Quanzhou Children's Hospital (Quanzhou Maternal and Child Health Hospital), Fengze District, Quanzhou City, Fujian Province, 362000, China
| | - Chengna Xu
- Pediatric Critical Care Medicine Department, Quanzhou Children's Hospital (Quanzhou Maternal and Child Health Hospital), Fengze District, Quanzhou City, Fujian Province, 362000, China
| | - Zhixu Chen
- Pediatric Critical Care Medicine Department, Quanzhou Children's Hospital (Quanzhou Maternal and Child Health Hospital), Fengze District, Quanzhou City, Fujian Province, 362000, China
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Feldman C, Theron AJ, Cholo MC, Anderson R. Cigarette Smoking as a Risk Factor for Tuberculosis in Adults: Epidemiology and Aspects of Disease Pathogenesis. Pathogens 2024; 13:151. [PMID: 38392889 PMCID: PMC10892798 DOI: 10.3390/pathogens13020151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 01/29/2024] [Accepted: 01/30/2024] [Indexed: 02/25/2024] Open
Abstract
It has been noted by the World Health Organisation that cases of tuberculosis in 2022 globally numbered 10.6 million, resulting in 1.3 million deaths, such that TB is one of the infectious diseases causing the greatest morbidity and mortality worldwide. Since as early as 1918, there has been an ongoing debate as to the relationship between cigarette smoking and TB. However, numerous epidemiological studies, as well as meta-analyses, have indicated that both active and passive smoking are independent risk factors for TB infection, development of reactivation TB, progression of primary TB, increased severity of cavitary disease, and death from TB, among several other considerations. With this considerable body of evidence confirming the association between smoking and TB, it is not surprising that TB control programmes represent a key potential preventative intervention. In addition to coverage of the epidemiology of TB and its compelling causative link with smoking, the current review is also focused on evidence derived from clinical- and laboratory-based studies of disease pathogenesis, most prominently the protective anti-mycobacterial mechanisms of the alveolar macrophage, the primary intracellular refuge of M. tuberculosis. This section of the review is followed by an overview of the major strategies utilised by the pathogen to subvert these antimicrobial mechanisms in the airway, which are intensified by the suppressive effects of smoke inhalation on alveolar macrophage function. Finally, consideration is given to a somewhat under-explored, pro-infective activity of cigarette smoking, namely augmentation of antibiotic resistance due to direct effects of smoke per se on the pathogen. These include biofilm formation, induction of cellular efflux pumps, which eliminate both smoke-derived toxicants and antibiotics, as well as gene modifications that underpin antibiotic resistance.
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Affiliation(s)
- Charles Feldman
- Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, York Road, Parktown, Johannesburg 2193, South Africa;
| | - Annette J. Theron
- Department of Immunology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Bophelo Road, Prinshof, Pretoria 0083, South Africa; (A.J.T.); (M.C.C.)
| | - Moloko C. Cholo
- Department of Immunology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Bophelo Road, Prinshof, Pretoria 0083, South Africa; (A.J.T.); (M.C.C.)
| | - Ronald Anderson
- Department of Immunology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Bophelo Road, Prinshof, Pretoria 0083, South Africa; (A.J.T.); (M.C.C.)
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Tanui CK, Tessema SK, Tegegne MA, Tebeje YK, Kaseya J. Unlocking the power of molecular and genomics tools to enhance cholera surveillance in Africa. Nat Med 2023; 29:2387-2388. [PMID: 37563243 DOI: 10.1038/s41591-023-02492-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Affiliation(s)
| | | | - Merawi Aragaw Tegegne
- Africa Centres for Disease Control and Prevention (Africa CDC), Addis Ababa, Ethiopia
| | - Yenew Kebede Tebeje
- Africa Centres for Disease Control and Prevention (Africa CDC), Addis Ababa, Ethiopia
| | - Jean Kaseya
- Africa Centres for Disease Control and Prevention (Africa CDC), Addis Ababa, Ethiopia
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Liu B, Zhang Y, Ren H, Yao Q, Ba J, Luan J, Zhao P, Qin Z, Qi Z. mTOR signaling regulates Zika virus replication bidirectionally through autophagy and protein translation. J Med Virol 2023; 95:e28422. [PMID: 36546404 DOI: 10.1002/jmv.28422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 12/10/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022]
Abstract
Zika virus (ZIKV) reemerged in 2016 and attracted much more attention worldwide. To date, the limited knowledge of ZIKV interactions with host cells in the early stages of infection impedes the prevention of viral epidemics and the treatment of ZIKV disease. The mammalian target of rapamycin (mTOR) signaling pathway plays an essential role in the regulation of autophagy and protein synthesis during multiple viral infections. This study aimed to investigate the functional role of mTOR signaling in ZIKV replication in human umbilical vein endothelial cells. Immunoblotting demonstrated that ZIKV infection inhibited mTORC1 signaling, enhancing autophagy but obstructing protein translation. Drugs or siRNA for interfering with mTOR signaling molecules were utilized to demonstrate that AKT/TSC2/mTORC1 signaling was involved in ZIKV infection and that autophagy promoted ZIKV production, but viral protein expression was regulated by mTORC1 signaling. Moreover, confocal microscopy indicated a robust correlation between autophagy and viral RNA transcription. This study clarifies the dual functions of mTOR signaling during ZIKV infection and provides theoretical support for developing potential anti-ZIKV drugs based on mTOR signaling molecules and deeper insights to better understand the mechanism between ZIKV and host cells.
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Affiliation(s)
- Bin Liu
- Department of Microbiology, Naval Medical University, Shanghai Key Laboratory of Medical Biodefense, Shanghai, China.,Naval Medical Center, Naval Medical University, Shanghai, China
| | - Yahui Zhang
- Department of Cardiology, Shanghai East Hospital, Tongji University, Shanghai, China
| | - Hao Ren
- Department of Microbiology, Naval Medical University, Shanghai Key Laboratory of Medical Biodefense, Shanghai, China
| | - Qiufeng Yao
- Department of Microbiology, Naval Medical University, Shanghai Key Laboratory of Medical Biodefense, Shanghai, China
| | - Jianbo Ba
- Naval Medical Center, Naval Medical University, Shanghai, China
| | - Jie Luan
- Naval Medical Center, Naval Medical University, Shanghai, China
| | - Ping Zhao
- Department of Microbiology, Naval Medical University, Shanghai Key Laboratory of Medical Biodefense, Shanghai, China
| | - Zhaoling Qin
- Department of Microbiology, Naval Medical University, Shanghai Key Laboratory of Medical Biodefense, Shanghai, China
| | - Zhongtian Qi
- Department of Microbiology, Naval Medical University, Shanghai Key Laboratory of Medical Biodefense, Shanghai, China
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Suzuki Y, Kami D, Taya T, Sano A, Ogata T, Matoba S, Gojo S. ZLN005 improves the survival of polymicrobial sepsis by increasing the bacterial killing via inducing lysosomal acidification and biogenesis in phagocytes. Front Immunol 2023; 14:1089905. [PMID: 36820088 PMCID: PMC9938763 DOI: 10.3389/fimmu.2023.1089905] [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: 11/04/2022] [Accepted: 01/23/2023] [Indexed: 02/07/2023] Open
Abstract
Polymicrobial sepsis still has a high mortality rate despite the development of antimicrobial agents, elaborate strategies to protect major organs, and the investment of numerous medical resources. Mitochondrial dysfunction, which acts as the center of energy metabolism, is clearly the basis of pathogenesis. Drugs that act on PGC1α, the master regulator of mitochondrial biosynthesis, have shown useful effects in the treatment of sepsis; therefore, we investigated the efficacy of ZLN005, a PGC1α agonist, and found significant improvement in overall survival in an animal model. The mode of action of this effect was examined, and it was shown that the respiratory capacity of mitochondria was enhanced immediately after administration and that the function of TFEB, a transcriptional regulator that promotes lysosome biosynthesis and mutually enhances PGC1α, was enhanced, as was the physical contact between mitochondria and lysosomes. ZLN005 strongly supported immune defense in early sepsis by increasing lysosome volume and acidity and enhancing cargo degradation, resulting in a significant reduction in bacterial load. ZLN005 rapidly acted on two organelles, mitochondria and lysosomes, against sepsis and interactively linked the two to improve the pathogenesis. This is the first demonstration that acidification of lysosomes by a small molecule is a mechanism of action in the therapeutic strategy for sepsis, which will have a significant impact on future drug discovery.
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Affiliation(s)
- Yosuke Suzuki
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Daisuke Kami
- Department of Regenerative Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Toshihiko Taya
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Arata Sano
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Takehiro Ogata
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan.,Department of Pathology and Cell Regulation, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Satoaki Matoba
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Satoshi Gojo
- Department of Regenerative Medicine, Graduate School of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
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