title: Modeling tuberculous meningitis in zebrafish using Mycobacterium marinum.
abstract: Tuberculous meningitis (TBM) is one of the most severe extrapulmonary manifestations of tuberculosis, with a high morbidity and mortality. Characteristic pathological features of TBM are Rich foci, i.e. brain- and spinal-cord-specific granulomas formed after hematogenous spread of pulmonary tuberculosis. Little is known about the early pathogenesis of TBM and the role of Rich foci. We have adapted the zebrafish model of Mycobacterium marinum infection (zebrafish-M. marinum model) to study TBM. First, we analyzed whether TBM occurs in adult zebrafish and showed that intraperitoneal infection resulted in granuloma formation in the meninges in 20% of the cases, with occasional brain parenchyma involvement. In zebrafish embryos, bacterial infiltration and clustering of infected phagocytes was observed after infection at three different inoculation sites: parenchyma, hindbrain ventricle and caudal vein. Infection via the bloodstream resulted in the formation of early granulomas in brain tissue in 70% of the cases. In these zebrafish embryos, infiltrates were located in the proximity of blood vessels. Interestingly, no differences were observed when embryos were infected before or after early formation of the blood-brain barrier (BBB), indicating that bacteria are able to cross this barrier with relatively high efficiency. In agreement with this observation, infected zebrafish larvae also showed infiltration of the brain tissue. Upon infection of embryos with an M. marinum ESX-1 mutant, only small clusters and scattered isolated phagocytes with high bacterial loads were present in the brain tissue. In conclusion, our adapted zebrafish-M. marinum infection model for studying granuloma formation in the brain will allow for the detailed analysis of both bacterial and host factors involved in TBM. It will help solve longstanding questions on the role of Rich foci and potentially contribute to the development of better diagnostic tools and therapeutics.
authors.affiliation: Department of Pediatric Infectious Diseases and Immunology, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands Department of Medical Microbiology and Infection Control, VU University Medical Center, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands.
authors.forename: Lisanne M
authors.initials: LM
authors.lastname: van Leeuwen
authors.affiliation: Department of Pediatric Infectious Diseases and Immunology, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
authors.forename: Martijn
authors.initials: M
authors.lastname: van der Kuip
authors.affiliation: Department of Pathobiology, Utrecht University, Faculty of Veterinary Medicine, Yalelaan 1, 3508 TB, Utrecht, The Netherlands.
authors.forename: Sameh A
authors.initials: SA
authors.lastname: Youssef
authors.affiliation: Department of Pathobiology, Utrecht University, Faculty of Veterinary Medicine, Yalelaan 1, 3508 TB, Utrecht, The Netherlands.
authors.forename: Alain
authors.initials: A
authors.lastname: de Bruin
authors.affiliation: Department of Medical Microbiology and Infection Control, VU University Medical Center, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands.
authors.forename: Wilbert
authors.initials: W
authors.lastname: Bitter
authors.affiliation: Department of Pediatric Infectious Diseases and Immunology, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
authors.forename: A Marceline
authors.initials: AM
authors.lastname: van Furth
authors.affiliation: Department of Medical Microbiology and Infection Control, VU University Medical Center, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands a.vandersar@vumc.nl.
authors.forename: Astrid M
authors.initials: AM
authors.lastname: van der Sar
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier; D004195:Disease Models, Animal; D009165:Mycobacterium Infections, Nontuberculous / Q000382:microbiology; D019910:Mycobacterium marinum / Q000502:physiology*; D014390:Tuberculosis, Meningeal / Q000382:microbiology*; D015027:Zebrafish
keywords: Blood-brain barrier; ESX-1 mutant; Mycobacterium marinum; Tuberculosis; Tuberculous meningitis; Zebrafish