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Kachlany SC, Vega BA. Therapeutic Applications of Aggregatibacter actinomycetemcomitans Leukotoxin. Pathogens 2024; 13:354. [PMID: 38787206 PMCID: PMC11123898 DOI: 10.3390/pathogens13050354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024] Open
Abstract
Aggregatibacter actinomycetemcomitans is a Gram-negative oral bacterium that has been primarily studied for its role in causing periodontal disease. The bacterium has also been implicated in several systemic diseases such as endocarditis and soft tissue abscesses. Leukotoxin (LtxA) is perhaps the best studied protein virulence factor from A. actinomycetemcomitans. The protein can rapidly destroy white blood cells (WBCs), helping the bacterium to subvert the host immune system. The functional receptor for LtxA is lymphocyte function associated antigen-1 (LFA-1), which is expressed exclusively on the surfaces of WBCs. Bacterial expression and secretion of the protein are highly regulated and controlled by a number of genetic and environmental factors. The mechanism of LtxA action on WBCs varies depending on the type of cell that is being killed, and the protein has been shown to activate numerous cell death pathways in susceptible cells. In addition to serving as an important virulence factor for the bacterium, because of its exquisite specificity and rapid activity, LtxA is also being investigated as a therapeutic agent that may be used to treat diseases such as hematological malignancies and autoimmune/inflammatory diseases. It is our hope that this review will inspire an increased intensity of research related to LtxA and its effect on Aggressive Periodontitis, the disease that led to its initial discovery.
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Affiliation(s)
- Scott C. Kachlany
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ 07103, USA
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Sun L, Zhu Z, Jia X, Ying X, Wang B, Wang P, Zhang S, Yu J. The difference of human gut microbiome in colorectal cancer with and without metastases. Front Oncol 2022; 12:982744. [PMID: 36387258 PMCID: PMC9665410 DOI: 10.3389/fonc.2022.982744] [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: 06/30/2022] [Accepted: 09/30/2022] [Indexed: 01/24/2023] Open
Abstract
Metastasis of colorectal cancer is deemed to be closely related to the changes in the human gut microbiome. The purpose of our study is to distinguish the differences in gut microbiota between colorectal cancer with and without metastases. Firstly, this study recruited colorectal cancer patients who met the established inclusion and exclusion criteria in the Oncology Department of Zhejiang Hospital of Traditional Chinese Medicine from February 2019 to June 2019. Fresh stool samples from healthy volunteers, non-metastatic patients, and metastatic patients were collected for 16S rRNA gene sequencing, to analyze the diversity and abundance of intestinal microorganisms in each group. The results showed that the microbial composition of the control group was more aplenty than the experimental group, while the difference also happened in the Tumor and the metastases group. At the phylum level, the abundance of Bacteroidetes significantly declined in the Tumor and the metastases group, compared with the control group. At the class level, Bacilli increased in experimental groups, while its abundance in the Tumor group was significantly higher than that in the metastases group. At the order level, the Tumor group had the highest abundance of Lactobacillales, followed by the metastases group and the control group had the lowest abundance. Overall, our study showed that the composition of the flora changed with the occurrence of metastasis in colorectal cancer. Therefore, the analysis of gut microbiota can serve as a supplement biological basis for the diagnosis and treatment of metastatic colorectal cancer which may offer the potential to develop non-invasive diagnostic tests.
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Affiliation(s)
- Leitao Sun
- Department of Medical Oncology, The First Affiliated Hospital of Zhejiang Chinese Medical University (Zhejiang Provincial Hospital of Chinese Medicine), Hangzhou, Zhejiang, China
| | - Zhenzheng Zhu
- The First School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Xinru Jia
- The First School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Xiangchang Ying
- The First School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Binbin Wang
- Department of Medical Oncology, The First Affiliated Hospital of Zhejiang Chinese Medical University (Zhejiang Provincial Hospital of Chinese Medicine), Hangzhou, Zhejiang, China
| | - Peipei Wang
- The First School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China,*Correspondence: Jieru Yu, ; Shuo Zhang, ; Peipei Wang,
| | - Shuo Zhang
- The Second Affiliated Hospital of Zhejiang Chinese Medical University (Xinhua Hospital of Zhejiang Province), Hangzhou, Zhejiang, China,*Correspondence: Jieru Yu, ; Shuo Zhang, ; Peipei Wang,
| | - Jieru Yu
- School of Basic Medical Sciences, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China,*Correspondence: Jieru Yu, ; Shuo Zhang, ; Peipei Wang,
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Filipi K, Rahman WU, Osickova A, Osicka R. Kingella kingae RtxA Cytotoxin in the Context of Other RTX Toxins. Microorganisms 2022; 10:microorganisms10030518. [PMID: 35336094 PMCID: PMC8953716 DOI: 10.3390/microorganisms10030518] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 12/04/2022] Open
Abstract
The Gram-negative bacterium Kingella kingae is part of the commensal oropharyngeal flora of young children. As detection methods have improved, K. kingae has been increasingly recognized as an emerging invasive pathogen that frequently causes skeletal system infections, bacteremia, and severe forms of infective endocarditis. K. kingae secretes an RtxA cytotoxin, which is involved in the development of clinical infection and belongs to an ever-growing family of cytolytic RTX (Repeats in ToXin) toxins secreted by Gram-negative pathogens. All RTX cytolysins share several characteristic structural features: (i) a hydrophobic pore-forming domain in the N-terminal part of the molecule; (ii) an acylated segment where the activation of the inactive protoxin to the toxin occurs by a co-expressed toxin-activating acyltransferase; (iii) a typical calcium-binding RTX domain in the C-terminal portion of the molecule with the characteristic glycine- and aspartate-rich nonapeptide repeats; and (iv) a C-proximal secretion signal recognized by the type I secretion system. RTX toxins, including RtxA from K. kingae, have been shown to act as highly efficient ‘contact weapons’ that penetrate and permeabilize host cell membranes and thus contribute to the pathogenesis of bacterial infections. RtxA was discovered relatively recently and the knowledge of its biological role remains limited. This review describes the structure and function of RtxA in the context of the most studied RTX toxins, the knowledge of which may contribute to a better understanding of the action of RtxA in the pathogenesis of K. kingae infections.
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Khan MA, Iqbal J, Ilyas M, Ayub AR, Zhu Y, Li H. Controlled supramolecular interaction to enhance the bioavailability of hesperetin to targeted cancer cells through graphyne: a comprehensive in silico study. RSC Adv 2022; 12:6336-6346. [PMID: 35424570 PMCID: PMC8982206 DOI: 10.1039/d1ra09112c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 01/24/2022] [Indexed: 02/06/2023] Open
Abstract
In the current study, the drug carrier efficiency of graphyne (GRP) for the transfer of the hesperetin (HPT) drug is evaluated for the first time. The GRP efficacy as a carrier is investigated using the density functional theory (DFT) technique to calculate various physiochemical characteristics such as dipole moment, bandgap, and chemical reactivity-descriptors for HPT, GRP and HPT@GRP complex. The non-covalent-interaction (NCI) plot indicated that GRP and HPT have weak interaction force, which is fundamental for the drug's noticeable offloading from the GRP carrier at its target location. According to frontier molecular orbital analysis, the highest occupied molecular orbital (HOMO) of HPT distributes the charge to the GRP, the lowest unoccupied molecular orbital (LUMO) during excitation. Charge transfer is further supported by charge-decomposition-analysis, which interprets the extensive overlap between HPT and GRP orbitals. In the case of the gas phase, the λmax of the HPT@GRP-complex is redshifted by 9 nm from GRP. In the solvent phase, the λmax value is also redshifted. These theoretically calculated spectra also match experimentally observed spectra rather well. The PET (photoinduced electron-transfer) method and electron–hole theory were used for the graphical explication of distinct excited states. The photoinduced electron transfer (PET) mechanism interprets fluorescence dimming because of interaction. Furthermore, GRP with cationic (+1) and anionic (−1) charge states (GRP+1/−1) showed minor structural disfigurement and formed stable HPT complexes. In the current study, HRP is loading and unloading on GRP very effectively, that can potentially be used in the oncology field. Due to this theoretical study, researchers will be interested in looking at other 2D nanomaterials for drug delivery applications. In the current study, the drug carrier efficiency of graphyne (GRP) for the transfer of the hesperetin (HPT) drug is evaluated for the first time.![]()
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Affiliation(s)
- Maroof Ahmad Khan
- Key Laboratory of Clusters Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology Beijing 100081 P. R. China +86 10 68912667
| | - Javed Iqbal
- Department of Chemistry, University of Agriculture Faisalabad-38000 Pakistan
| | - Mubashar Ilyas
- Department of Chemistry, University of Agriculture Faisalabad-38000 Pakistan
| | - Ali Raza Ayub
- Key Laboratory of Clusters Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology Beijing 100081 P. R. China +86 10 68912667
| | - Yanhong Zhu
- Key Laboratory of Clusters Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology Beijing 100081 P. R. China +86 10 68912667
| | - Hui Li
- Key Laboratory of Clusters Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology Beijing 100081 P. R. China +86 10 68912667
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Aggregatibacter actinomycetemcomitans Leukotoxin Activates the NLRP3 Inflammasome and Cell-to-Cell Communication. Pathogens 2022; 11:pathogens11020159. [PMID: 35215102 PMCID: PMC8877716 DOI: 10.3390/pathogens11020159] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 01/14/2022] [Accepted: 01/24/2022] [Indexed: 02/04/2023] Open
Abstract
Carriers of highly leukotoxic genotypes of Aggregatibacter actinomycetemcomitans are at high risk for rapid degradation of tooth-supporting tissues. The leukotoxin (LtxA) expressed by this bacterium induces a rapid pro-inflammatory response in leukocytes that results in cell death. The aim of the present study was to increase the understanding of LtxA-induced leukocyte activation mechanisms and of possible associated osteoclast differentiation. The effect of LtxA on activation of the inflammasome complex was studied in THP-1 wild type and in NLRP3- and ASC knockout cells. Cell-to-cell communication was assessed by fluorescent parachute assays, and THP-1 differentiation into osteoclast-like cells was investigated microscopically. The results showed that LtxA induced inflammatory cell death, which involved activation of the NLRP3 inflammasome and gap junction cell-to-cell communication. THP-1 cells treated with lipopolysaccharide (LPS) and LtxA together differentiated into an osteoclast-like phenotype. Here, LPS prevented LtxA-mediated cell death but failed to induce osteoclast differentiation on its own. However, pit formation was not significantly enhanced by LtxA. We conclude that A. actinomycetemcomitans leukotoxicity mediates activation of the NLRP3 inflammasome and cell-to-cell communication in the induced pro-inflammatory cell death. In addition, LtxA stimulated differentiation towards osteoclasts-like cells in LPS-treated THP-1 cells.
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