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Johansen MD, Spaink HP, Oehlers SH, Kremer L. Modeling nontuberculous mycobacterial infections in zebrafish. Trends Microbiol 2024; 32:663-677. [PMID: 38135617 DOI: 10.1016/j.tim.2023.11.011] [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: 10/24/2023] [Revised: 11/24/2023] [Accepted: 11/27/2023] [Indexed: 12/24/2023]
Abstract
The incidence of infections due to nontuberculous mycobacteria (NTM) has increased rapidly in recent years, surpassing tuberculosis in developed countries. Due to inherent antimicrobial resistance, NTM infections are particularly difficult to treat with low cure rates. There is an urgent need to understand NTM pathogenesis and to develop novel therapeutic approaches for the treatment of NTM diseases. Zebrafish have emerged as an excellent animal model due to genetic amenability and optical transparency during embryonic development, allowing spatiotemporal visualization of host-pathogen interactions. Furthermore, adult zebrafish possess fully functional innate and adaptive immunity and recapitulate important pathophysiological hallmarks of mycobacterial infection. Here, we report recent breakthroughs in understanding the hallmarks of NTM infections using the zebrafish model.
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Affiliation(s)
- Matt D Johansen
- Centre for Inflammation, Centenary Institute and University of Technology Sydney, Faculty of Science, School of Life Sciences, Sydney, NSW, Australia
| | - Herman P Spaink
- Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Stefan H Oehlers
- A*STAR Infectious Diseases Labs (A*STAR ID Labs), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Laurent Kremer
- Centre National de la Recherche Scientifique, UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 Route de Mende, 34293, Montpellier, France; INSERM, IRIM, 34293 Montpellier, France.
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Jang H, Kim CM, Ha HJ, Hong E, Park HH. Interdomain flexibility and putative active site was revealed by crystal structure of MltG from Acinetobacter baumannii. Biochem Biophys Res Commun 2024; 727:150318. [PMID: 38945066 DOI: 10.1016/j.bbrc.2024.150318] [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: 06/23/2024] [Revised: 06/24/2024] [Accepted: 06/26/2024] [Indexed: 07/02/2024]
Abstract
MltG, positioned within the inner membrane of bacteria, functions as a lytic transglycosylase (LT) essential for integrating into the cell wall by cleaving the newly synthesized glycan strand, emphasizing its critical involvement in bacterial cell wall biosynthesis and remodeling. Current study reported the first structure of MltG family of LT. We have elucidated the structure of MltG from Acinetobacter baumannii (abMltG), a formidable superbug renowned for its remarkable antibiotic resistance. Our structural and biochemical investigations unveiled the presence of a flexible peptidoglycan (PG)-binding domain (PGD) within MltG family, which exists as a monomer in solution. Furthermore, we delineated the putative active site of abMltG via a combination of structural analysis and sequence comparison. This discovery enhances our comprehension of the transglycosylation process mediated by the MltG family, offering insights that could inform the development of novel antibiotics tailored to combat A. baumannii.
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Affiliation(s)
- Hyunseok Jang
- College of Pharmacy, Chung-Ang University, Seoul, 06974, Republic of Korea; Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Chang Min Kim
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Hyun Ji Ha
- College of Pharmacy, Chung-Ang University, Seoul, 06974, Republic of Korea; Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Eunmi Hong
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, 41061, Republic of Korea
| | - Hyun Ho Park
- College of Pharmacy, Chung-Ang University, Seoul, 06974, Republic of Korea; Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul, 06974, Republic of Korea.
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Quantitative evaluation of Mycobacterium abscessus clinical isolate virulence using a silkworm infection model. PLoS One 2022; 17:e0278773. [PMID: 36538550 PMCID: PMC9767372 DOI: 10.1371/journal.pone.0278773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 11/23/2022] [Indexed: 12/24/2022] Open
Abstract
Mycobacterium abscessus causes chronic skin infections, lung diseases, and systemic or disseminated infections. Here we investigated whether the virulence of M. abscessus clinical isolates could be evaluated by calculating the median lethal dose (LD50) in a silkworm infection model. M. abscessus subsp. abscessus cells were injected into the silkworm hemolymph. When reared at 37˚C, the silkworms died within 2 days post-infection with M. abscessus subsp. abscessus. Viable cell numbers of M. abscessus increased in the hemolymph of silkworms injected with M. abscessus. Silkworms were not killed by injections with heat-killed M. abscessus cells. The administration of clarithromycin, an antibacterial drug used to treat the infection in humans, prolonged the survival time of silkworms injected with M. abscessus. The LD50 values of 7 clinical isolates in the silkworm infection model were differed by up to 9-fold. The Mb-17 isolate, which was identified as a virulent strain in the silkworm infection model, induced more detachment of human THP-1-derived macrophages during infection than the Mb-10 isolate. These findings suggest that the silkworm M. abscessus infection model can be used to quantitatively evaluate the virulence of M. abscessus clinical isolates in a short time period.
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Guryanova SV. Regulation of Immune Homeostasis via Muramyl Peptides-Low Molecular Weight Bioregulators of Bacterial Origin. Microorganisms 2022; 10:microorganisms10081526. [PMID: 36013944 PMCID: PMC9413341 DOI: 10.3390/microorganisms10081526] [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: 07/04/2022] [Revised: 07/20/2022] [Accepted: 07/22/2022] [Indexed: 12/10/2022] Open
Abstract
Metabolites and fragments of bacterial cells play an important role in the formation of immune homeostasis. Formed in the course of evolution, symbiotic relationships between microorganisms and a macroorganism are manifested, in particular, in the regulation of numerous physiological functions of the human body by the innate immunity receptors. Low molecular weight bioregulators of bacterial origin have recently attracted more and more attention as drugs in the prevention and composition of complex therapy for a wide range of diseases of bacterial and viral etiology. Signaling networks show cascades of causal relationships of deterministic phenomena that support the homeostasis of multicellular organisms at different levels. To create networks, data from numerous biomedical and clinical research databases were used to prepare expert systems for use in pharmacological and biomedical research with an emphasis on muramyl dipeptides. Muramyl peptides are the fragments of the cell wall of Gram-positive and Gram-negative bacteria. Binding of muramyl peptides with intracellular NOD2 receptors is crucial for an immune response on pathogens. Depending on the microenvironment and duration of action, muramyl peptides possess positive or negative regulation of inflammation. Other factors, such as genetic, pollutions, method of application and stress also contribute and should be taken into account. A system biology approach should be used in order to systemize all experimental data for rigorous analysis, with the aim of understanding intrinsic pathways of homeostasis, in order to define precise medicine therapy and drug design.
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Affiliation(s)
- Svetlana V Guryanova
- Medical Institute, Peoples' Friendship University of Russia (RUDN University) of the Ministry of Science and Higher Education of the Russian Federation, 117198 Moscow, Russia
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Ferrell KC, Johansen MD, Triccas JA, Counoupas C. Virulence Mechanisms of Mycobacterium abscessus: Current Knowledge and Implications for Vaccine Design. Front Microbiol 2022; 13:842017. [PMID: 35308378 PMCID: PMC8928063 DOI: 10.3389/fmicb.2022.842017] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/08/2022] [Indexed: 12/22/2022] Open
Abstract
Mycobacterium abscessus is a member of the non-tuberculous mycobacteria (NTM) group, responsible for chronic infections in individuals with cystic fibrosis (CF) or those otherwise immunocompromised. While viewed traditionally as an opportunistic pathogen, increasing research into M. abscessus in recent years has highlighted its continued evolution into a true pathogen. This is demonstrated through an extensive collection of virulence factors (VFs) possessed by this organism which facilitate survival within the host, particularly in the harsh environment of the CF lung. These include VFs resembling those of other Mycobacteria, and non-mycobacterial VFs, both of which make a notable contribution in shaping M. abscessus interaction with the host. Mycobacterium abscessus continued acquisition of VFs is cause for concern and highlights the need for novel vaccination strategies to combat this pathogen. An effective M. abscessus vaccine must be suitably designed for target populations (i.e., individuals with CF) and incorporate current knowledge on immune correlates of protection against M. abscessus infection. Vaccination strategies must also build upon lessons learned from ongoing efforts to develop novel vaccines for other pathogens, particularly Mycobacterium tuberculosis (M. tb); decades of research into M. tb has provided insight into unconventional and innovative vaccine approaches that may be applied to M. abscessus. Continued research into M. abscessus pathogenesis will be critical for the future development of safe and effective vaccines and therapeutics to reduce global incidence of this emerging pathogen.
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Affiliation(s)
- Kia C. Ferrell
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
- Tuberculosis Research Program, Centenary Institute, Sydney, NSW, Australia
- *Correspondence: Kia C. Ferrell,
| | - Matt D. Johansen
- Centre for Inflammation, Centenary Institute, University of Technology, Sydney, NSW, Australia
- Faculty of Science, School of Life Sciences, University of Technology, Sydney, NSW, Australia
| | - James A. Triccas
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
- Sydney Institute for Infectious Diseases and the Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
| | - Claudio Counoupas
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
- Tuberculosis Research Program, Centenary Institute, Sydney, NSW, Australia
- Sydney Institute for Infectious Diseases and the Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
- Claudio Counoupas,
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Liu H, Gui X, Chen S, Fu W, Li X, Xiao T, Hou J, Jiang T. Structural Variability of Lipoarabinomannan Modulates Innate Immune Responses within Infected Alveolar Epithelial Cells. Cells 2022; 11:cells11030361. [PMID: 35159170 PMCID: PMC8834380 DOI: 10.3390/cells11030361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/15/2022] [Accepted: 01/18/2022] [Indexed: 02/04/2023] Open
Abstract
Mycobacterium tuberculosis (M. tb) is an intracellular pathogen persisting in phagosomes that has the ability to escape host immune surveillance causing tuberculosis (TB). Lipoarabinomannan (LAM), as a glycolipid, is one of the complex outermost components of the mycobacterial cell envelope and plays a critical role in modulating host responses during M. tb infection. Different species within the Mycobacterium genus exhibit distinct LAM structures and elicit diverse innate immune responses. However, little is known about the mechanisms. In this study, we first constructed a LAM-truncated mutant with fewer arabinofuranose (Araf) residues named M. sm-ΔM_6387 (Mycobacterium smegmatis arabinosyltransferase EmbC gene knockout strain). It exhibited some prominent cell wall defects, including tardiness of mycobacterial migration, loss of acid-fast staining, and increased cell wall permeability. Within alveolar epithelial cells (A549) infected by M. sm-ΔM_6387, the uptake rate was lower, phagosomes with bacterial degradation appeared, and microtubule-associated protein light chain 3 (LC3) recruitment was enhanced compared to wild type Mycobacterium smegmatis (M. smegmatis). We further confirmed that the variability in the removal capability of M. sm-ΔM_6387 resulted from host cell responses rather than the changes in the mycobacterial cell envelope. Moreover, we found that M. sm-ΔM_6387 or its glycolipid extracts significantly induced expression changes in some genes related to innate immune responses, including Toll-like receptor 2 (TLR2), class A scavenger receptor (SR-A), Rubicon, LC3, tumor necrosis factor alpha (TNF-α), Bcl-2, and Bax. Therefore, our studies suggest that nonpathogenic M. smegmatis can deposit LC3 on phagosomal membranes, and the decrease in the quantity of Araf residues for LAM molecules not only impacts mycobacterial cell wall integrity but also enhances host defense responses against the intracellular pathogens and decreases phagocytosis of host cells.
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Affiliation(s)
- Hanrui Liu
- Department of Biotechnology, The College of Basic Medical Science, Dalian Medical University, Dalian 116044, China; (H.L.); (X.G.); (W.F.); (X.L.); (T.X.); (J.H.)
| | - Xuwen Gui
- Department of Biotechnology, The College of Basic Medical Science, Dalian Medical University, Dalian 116044, China; (H.L.); (X.G.); (W.F.); (X.L.); (T.X.); (J.H.)
| | - Shixing Chen
- Key Laboratory of Science and Technology on Microsystem, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China;
| | - Weizhe Fu
- Department of Biotechnology, The College of Basic Medical Science, Dalian Medical University, Dalian 116044, China; (H.L.); (X.G.); (W.F.); (X.L.); (T.X.); (J.H.)
| | - Xiang Li
- Department of Biotechnology, The College of Basic Medical Science, Dalian Medical University, Dalian 116044, China; (H.L.); (X.G.); (W.F.); (X.L.); (T.X.); (J.H.)
| | - Tingyuan Xiao
- Department of Biotechnology, The College of Basic Medical Science, Dalian Medical University, Dalian 116044, China; (H.L.); (X.G.); (W.F.); (X.L.); (T.X.); (J.H.)
| | - Jie Hou
- Department of Biotechnology, The College of Basic Medical Science, Dalian Medical University, Dalian 116044, China; (H.L.); (X.G.); (W.F.); (X.L.); (T.X.); (J.H.)
| | - Tao Jiang
- Department of Biotechnology, The College of Basic Medical Science, Dalian Medical University, Dalian 116044, China; (H.L.); (X.G.); (W.F.); (X.L.); (T.X.); (J.H.)
- Correspondence: ; Tel.: +86-411-8611-0350
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