Projects per year
Abstract
Innate cellular immune responses are a critical first-line defense against invading bacterial pathogens. Leukocyte migration from the bloodstream to a site of infection is mediated by chemotactic factors that are often host-derived. More recently, there has been a greater appreciation of the importance of bacterial factors driving neutrophil movement during infection. Here, we describe the development of a zebrafish infection model to study Acinetobacter baumannii pathogenesis. By using isogenic A. baumannii mutants lacking expression of virulence effector proteins, we demonstrated that bacterial drivers of disease severity are conserved between zebrafish and mammals. By using transgenic zebrafish with fluorescent phagocytes, we showed that a mutation of an established A. baumannii global virulence regulator led to marked changes in neutrophil behavior involving rapid neutrophil influx to a localized site of infection, followed by prolonged neutrophil dwelling. This neutrophilic response augmented bacterial clearance and was secondary to an impaired A. baumannii phenylacetic acid catabolism pathway, which led to accumulation of phenylacetate. Purified phenylacetate was confirmed to be a neutrophil chemoattractant. These data identify a previously unknown mechanism of bacterial-guided neutrophil chemotaxis in vivo, providing insight into the role of bacterial metabolism in host innate immune evasion. Furthermore, the work provides a potentially new therapeutic paradigm of targeting a bacterial metabolic pathway to augment host innate immune responses and attenuate disease.
Original language | English |
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Article number | 1523116113 |
Pages (from-to) | 9599-9604 |
Number of pages | 6 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 113 |
Issue number | 34 |
DOIs | |
Publication status | Published - 23 Aug 2016 |
Keywords
- Acinetobacter baumannii
- Chemotaxis
- Neutrophils
- Phenylacetate
- Zebrafish
Projects
- 1 Finished
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Mechanisms of disease caused by hospital-acquired pathogens
National Health and Medical Research Council (NHMRC) (Australia)
1/01/13 → 31/12/16
Project: Research
Equipment
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Monash Micro Imaging
Stephen Firth (Manager), Alex Fulcher (Operator), Oleks Chernyavskiy (Operator), Margaret Rzeszutek (Other), David Potter (Manager), Volker Hilsenstein (Operator), Juan Nunez-Iglesias (Other), Stephen Cody (Manager), Irena Carmichael (Operator), Betty Kouskousis (Other), Sarah Creed (Manager) & Giulia Ballerin (Operator)
Faculty of Medicine Nursing and Health Sciences Research PlatformsFacility/equipment: Facility