Bacterial regulation by the second messenger c-di-GMP in Bordetella and respiratory pathogens.
Overview
The second messenger c-di-GMP is present in most bacteria and regulates a variety of phenotypes, including polysaccharide synthesis, biofilm formation and motility. c-di-GMP levels have also been shown to determine bacterial virulence. This molecule is synthesized intracellularly by diguanylate cyclases (DGCs) and degraded by specific phosphodiesterases (PDEs). Thus, in response to different stimuli, bacteria regulate their intracellular c-di-GMP concentrations.
A central feature of c-di-GMP regulation is that it operates at different levels. On the one hand, it regulates response regulators by stimulating or inhibiting the expression of specific genes through binding to proteins and inducing conformational changes. These changes result in rapid modifications of protein activity and, consequently, of the bacterial phenotype.
In the context of Bordetella pathogenesis, c-di-GMP is particularly relevant because it may regulate phenotypic changes when rapid adaptation is required, such as during transmission, when the bacterium moves from an abiotic environment —the air— to the mucosa of a new host.
Research lines
Study of proteins involved in c-di-GMP homeostasis
Systematic analysis of the proteins that regulate the concentration of the second messenger c-di-GMP in Bordetella.
Bordetella bronchiseptica has 19 candidate proteins with possible diguanylate cyclase (DGC) or phosphodiesterase (PDE) activity. In other bacteria, each of these enzymes regulates specific phenotypes in which c-di-GMP is involved.
We systematically study the role of each DGC and PDE in B. bronchiseptica. B. pertussis, the causative agent of human whooping cough, has fewer candidate proteins and a DGC absent in B. bronchiseptica, whose analysis is especially relevant to understanding the differential regulation of this second messenger.
Participants: Julieta Fernández, Federico Sisti, Keila Belhart and Federico Zacca.
Study of the pathogenesis of an important pathogen in cattle production: Mannheimia haemolytica
Characterization of the mechanisms responsible for bovine respiratory disease to develop more efficient metaphylactic treatments.
Bovine respiratory disease is one of the main conditions in intensive production systems, especially at the start of feedlot fattening. Young calves are exposed to stressors such as long journeys, dietary changes and hierarchical reorganization in pens.
Associated agents include viruses and bacteria such as Pasteurella multocida and M. haemolytica. The disease causes losses through lower average daily weight gain, longer time to slaughter weight, reduced carcass quality and mortality.
The aim is to lay the groundwork for understanding the pathogenesis mechanisms of M. haemolytica and to apply that knowledge to the development of more effective therapeutic and metaphylactic strategies.
Participants: Julieta Fernández, Agustín Franchi and Federico Sisti.
Regulation of biofilm formation by a porcine respiratory pathogen through components present in vivo
Study of host signals that regulate formation and disassembly of the biofilm of Bordetella bronchiseptica.
Biofilm is a key structure during infection by B. bronchiseptica. At stages after its establishment, the bacterium detects host components that trigger its disassembly and stimulate secretion of toxins and adhesins.
This mechanism could facilitate colonization of new areas of the respiratory tract or dissemination to other hosts. We analyze the regulatory mechanisms involved and the role of adhesins such as filamentous hemagglutinin (FHA) and BrtA, as well as of adenylate cyclase (AC) toxin.
The line also evaluates the function of AC and of c-di-GMP metabolism in the different stages of biofilm formation and disassembly.
Participants: Julieta Fernández, Agustín Franchi and Sabrina Mugni.
Team
- Dra. Julieta FernándezIndependent Researcher (CONICET); Associate Professor UNLP
- Dr. Federico SistiIndependent Researcher (CONICET); Associate Professor UNLP
- Clara KasiztkyGraduate Fellow UNLP
- Bioq. Agustín FranchiDoctoral Fellow (CONICET)
- Dra. Sabrina MugniPostdoctoral researcher
- Undergraduate fellows and internsValentina Giaccone; Valentina García; Nicolás Villafañe; Candela Sedano; Ezequiel Villafañe; Franco Gallo; Erika Volpi; Rosario Acha
- Pilar ValsecchiIntern
Projects and funding
| Project | Code / period | Entity |
|---|---|---|
| Regulation of B. bronchiseptica type III secretion system by c-di-GMP | PICT 2023–2027 · Team 2021–00937 · 2023–2027 | ANPCyT |
| Biofilm formation regulation in respiratory pathogens | Project X1008 · UNLP Incentives 2022–2026 · 2022–2026 | UNLP |
| Porcine respiratory pathogen biofilm regulation by in vivo components | PICT IA 2019–00680 · 2019–2023 | ANPCyT |
| Mannheimia haemolytica pathogenesis (bovine BRD) | PICT IA 2018–04404 · 2020–2023 | ANPCyT |
| Lap system role in B. bronchiseptica biofilm and pathogenesis | PICT Type D 2016–0492 · 2017–2019 | FONCyT–ANPCyT |
Selected scientific output
- Architecture and regulatory functions of c-di-GMP signaling in classical Bordetella species
- Microbes without borders: uniting societies for climate action
- Interplay of virulence factors and signaling molecules: albumin and calcium-mediated biofilm regulation in Bordetella bronchiseptica
- BvgR is important for virulence-related phenotypes in Bordetella bronchiseptica
- Draft genome sequence of Mannheimia haemolytica strain Oliden, isolated from a calf lung infection in Argentina
Collaborations
- Monica Cartelle Gestal (LSU Health, Shreveport, USA)
- Dra. Eloísa Arana (Institute of Immunology, Genetics and Metabolism, CONICET)
- George A. O’Toole (Geisel School of Medicine, Dartmouth, USA)
- F. Heath Damron (bordetella.org, USA)
- Erik Hewlett (Univ. Virginia, USA)
- Eric Harvill (Univ. Georgia, USA)
Capabilities, developments and transfer
c-di-GMP homeostasis and signaling studies in Bordetella.
Mannheimia haemolytica pathogenesis characterization in bovine BRD.
Genetic methods for allelic exchange in B. bronchiseptica.
Supplementary material
Supplementary material associated with Gutierrez et al. 2022 (Infect Immun; doi: 10.1128/iai.00107-22), referenced on the institutional site.
- Gutierrez et al. 2022 — Cyclic di-GMP Regulates the Type III Secretion System and Virulence in Bordetella bronchiseptica. Infect Immun 90(6):e0010722 · doi: 10.1128/iai.00107-22
- Supplementary material (Google Drive)
Institutional contact
Institutional channels of the Institute.