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Abdulrehman T, Qadri S, Skariah S, Sultan A, Mansour S, Azzi J, Haik Y. Boron doped silver-copper alloy nanoparticle targeting intracellular S. aureus in bone cells. PLoS One 2020; 15:e0231276. [PMID: 32275737 PMCID: PMC7147743 DOI: 10.1371/journal.pone.0231276] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/19/2020] [Indexed: 02/08/2023] Open
Abstract
OBJECTIVES Alloyed metallic nanoparticles of silver and copper are effective against intracellular infection. However, systemic toxicity may arise due to the non-specific delivery of the nanoparticles. In addressing the issue, this study deals with the targeting of silver-copper-boron (ACB) nanoparticles to infected osteoblasts, which could decrease systemic toxicity and form the basis of targeting specific markers expressed in bone infections. METHODS ACB nanoparticles were synthesized and conjugated to the Cadherin-11 antibody (OBAb). The effect of targeting nanoparticles against extracellular and intracellular S. aureus was determined by enumeration of bacterial growth. The binding of the targeting nanoparticles to infected osteoblasts as well as the visualization of live/dead bacteria due to treatment was carried out using fluorescence microscopy. MTT assay was used to determine the viability of osteoblasts with different concentrations of the nanoparticles. RESULTS The ACB nanoparticles conjugated to OBAb (ACB-OBAb) were effective against extracellular S. aureus. The ACB-OBAb nanoparticles showed a 1.32 log reduction of intracellular S. aureus at a concentration of 1mg/L. The ACB-OBAb nanoparticles were able to bind to the infected osteoblast and showed toxicity to osteoblasts at levels ≥20mg/L. Also, the percentage of silver, copper, and boron in the nanoparticles determined the effectiveness of their antibacterial activity. CONCLUSION The ACB-OBAb nanoparticles were able to target the osteoblasts and demonstrated significant antibacterial activity against intracellular S. aureus. Targeting shows promise as a strategy to target specific markers expressed on infected osteoblasts for efficient nanoparticle delivery, and further animal studies are recommended to test its efficacy in vivo.
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Affiliation(s)
- Tahir Abdulrehman
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Shahnaz Qadri
- College of Science and Engineering, Hamad Bin Khalifa University, Doha, Qatar
| | - Sini Skariah
- Weil Cornell Medicine-Qatar, Education City, Doha, Qatar
| | - Ali Sultan
- Weil Cornell Medicine-Qatar, Education City, Doha, Qatar
| | - Said Mansour
- Qatar Environment and Energy Research Institute (QEERI), Hamad Bin Khalifa University, Doha, Qatar
| | - Jamil Azzi
- Brigham and Women’s Hospital, Harvard Medical School, Boston, United States of America
| | - Yousef Haik
- College of Science and Engineering, Hamad Bin Khalifa University, Doha, Qatar
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de Vor L, Rooijakkers SHM, van Strijp JAG. Staphylococci evade the innate immune response by disarming neutrophils and forming biofilms. FEBS Lett 2020; 594:2556-2569. [PMID: 32144756 DOI: 10.1002/1873-3468.13767] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/30/2020] [Accepted: 02/22/2020] [Indexed: 12/24/2022]
Abstract
Staphylococcus aureus and Staphylococcus epidermidis can cause many types of infections, ranging from skin infections to implant-associated infections. The primary innate immune response against bacterial infections involves complement activation, recruitment of phagocytes (most importantly neutrophils), and subsequent killing of the pathogen. However, staphylococci are not innocent bystanders; they actively obstruct this immune attack. To do that, S. aureus secretes several immune-evasion proteins to resist attack by the innate immune system. Furthermore, S. aureus and S. epidermidis are known for their ability to form biofilms on implanted medical devices and host tissues, which provides another important immune-evasion mechanism. Understanding these different strategies to resist immune attack will help to develop novel therapies against staphylococcal infections.
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Affiliation(s)
- Lisanne de Vor
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, The Netherlands
| | - Suzan H M Rooijakkers
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, The Netherlands
| | - Jos A G van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, The Netherlands
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Cai J, Li J, Zhou Y, Wang J, Li J, Cui L, Meng X, Zhu G, Wang H. Staphylococcus aureus facilitates its survival in bovine macrophages by blocking autophagic flux. J Cell Mol Med 2020; 24:3460-3468. [PMID: 31997584 PMCID: PMC7131951 DOI: 10.1111/jcmm.15027] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 12/16/2019] [Accepted: 01/13/2020] [Indexed: 12/16/2022] Open
Abstract
Staphylococcus aureus is a pathogen that is the causative agent of several human and veterinary infections and plays a critical role in the clinical and subclinical mastitis of cattle. Autophagy is a conserved pathogen defence mechanism in eukaryotes. Studies have reported that S aureus can subvert autophagy and survive in cells. Staphylococcus aureus survival in cells is an important cause of chronic persistent mastitis infection. However, it is unclear whether S aureus can escape autophagy in innate immune cells. In this study, initiation of autophagy due to the presence of S aureus was detected in bovine macrophages. We observed autophagic vacuoles increased after S aureus infection of bovine macrophages by transmission electron microscopy (TEM). It was also found that S aureus‐infected bovine macrophages increased the expression of LC3 at different times(0, 0.5, 1, 1.5, 2, 2.5, 3 and 4 hours). Data also showed the accumulation of p62 induced by S aureus infection. Application of autophagy regulatory agents showed that the degradation of p62 was blocked in S aureus induced bovine macrophages. In addition, we also found that the accumulation of autophagosomes promotes S aureus to survive in macrophage cells. In conclusion, this study indicates that autophagy occurs in S aureus‐infected bovine macrophages but is blocked at a later stage of autophagy. The accumulation of autophagosomes facilitates the survival of S aureus in bovine macrophages. These findings provide new insights into the interaction of S aureus with autophagy in bovine macrophages.
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Affiliation(s)
- Juan Cai
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Jun Li
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Yuqi Zhou
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Jianqiang Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Jianji Li
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Luying Cui
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Xia Meng
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Guoqiang Zhu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Heng Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
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Guo S, Zhou W, Wu J, Liu X, Meng Z, Tian J, Liu S, Ni M, Zhang J, Jia S, Li Y, Zhang X. Network pharmacology-based study on the mechanism of “Jiu Wei Zhu Huang San” in respiratory tract infections treatment. Eur J Integr Med 2019. [DOI: 10.1016/j.eujim.2019.101013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Lv Y, Fang L, Ding P, Liu R. PI3K/Akt-Beclin1 signaling pathway positively regulates phagocytosis and negatively mediates NF-κB-dependent inflammation in Staphylococcus aureus-infected macrophages. Biochem Biophys Res Commun 2019; 510:284-289. [PMID: 30700382 DOI: 10.1016/j.bbrc.2019.01.091] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 01/18/2019] [Indexed: 11/19/2022]
Abstract
Although autophagy and phagocytosis are involved in the regulation of host inflammatory response to bacterial infection in macrophages, the underlying mechanisms have not been completely elucidated. In the present study, we found that infecting RAW264.7 macrophages with Staphylococcus aureus (S. aureus) activated multiple signaling pathways including phosphatidylinositide 3-kinase (PI3K)/protein kinase B (Akt), nuclear factor-κB (NF-κB), and Rac1, as well as triggered autophagy. LY294002, a specific PI3K activity inhibitor, significantly decreased autophagy and phagocytosis of macrophages upon S. aureus infection. Similarly, knockdown of Beclin1 by specific siRNA significantly inhibited autophagy and phagocytosis of S. aureus-infected macrophages. Additionally, we showed that although administration of Beclin1 siRNA had no effects on phosphorylation of Akt (p-Akt), inhibition of PI3K activity by LY294002 significantly decreased the expression of Beclin1, suggesting that Beclin1 is a downstream molecular of PI3K. Furthermore, inhibition of autophagy significantly increased the production of NF-κB-dependent TNFα/IL-1β in S. aureus-infected macrophages. Collectively, these findings demonstrated, for the first time, that the PI3K/Akt-Beclin1 signaling pathway positively regulates phagocytosis and negatively mediates NF-κB-dependent inflammation in S. aureus-infected macrophages.
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Affiliation(s)
- Yunxiang Lv
- Department of Respiration, Anhui Geriatric Institute, First Affiliated Hospital, Anhui Medical University, Jixi Road 218, Hefei, Anhui, 230022, People's Republic of China
| | - Lei Fang
- Department of Respiration, Anhui Geriatric Institute, First Affiliated Hospital, Anhui Medical University, Jixi Road 218, Hefei, Anhui, 230022, People's Republic of China
| | - Peishan Ding
- Department of Respiration, Anhui Geriatric Institute, First Affiliated Hospital, Anhui Medical University, Jixi Road 218, Hefei, Anhui, 230022, People's Republic of China
| | - Rongyu Liu
- Department of Respiration, Anhui Geriatric Institute, First Affiliated Hospital, Anhui Medical University, Jixi Road 218, Hefei, Anhui, 230022, People's Republic of China.
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Enterococcus faecium TIR-Domain Genes Are Part of a Gene Cluster Which Promotes Bacterial Survival in Blood. Int J Microbiol 2019; 2018:1435820. [PMID: 30631364 PMCID: PMC6304867 DOI: 10.1155/2018/1435820] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 10/14/2018] [Indexed: 11/29/2022] Open
Abstract
Enterococcus faecium has undergone a transition to a multidrug-resistant nosocomial pathogen. The population structure of E. faecium is characterized by a sharp distinction of clades, where the hospital-adapted lineage is primarily responsible for bacteremia. So far, factors that were identified in hospital-adapted strains and that promoted pathogenesis of nosocomial E. faecium mainly play a role in adherence and biofilm production, while less is known about factors contributing to survival in blood. This study identified a gene cluster, which includes genes encoding bacterial Toll/interleukin-1 receptor- (TIR-) domain-containing proteins (TirEs). The cluster was found to be unique to nosocomial strains and to be located on a putative mobile genetic element of phage origin. The three genes within the cluster appeared to be expressed as an operon. Expression was detected in bacterial culture media and in the presence of human blood. TirEs are released into the bacterial supernatant, and TirE2 is associated with membrane vesicles. Furthermore, the tirE-gene cluster promotes bacterial proliferation in human blood, indicating that TirE may contribute to the pathogenesis of bacteremia.
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