Periodic Reporting for period 1 - ProLung (The role of maternal microbiota in offspring lung development and function)
Periodo di rendicontazione: 2019-01-01 al 2020-12-31
Summary of the context: The traditional belief, that healthy human lungs are sterile, is now considered debunked and scientific reports show that lung microbiota is altered in lung diseases such as asthma, chronic obstructive pulmonary disease and bronchopulmonary dysplasia (BPD). The control of early lung development is highly regulated and orchestrated and, although some pathways and signals mediating these events have been described, much remains unknown. Whilst it now is well known, that microbiota drives the development of the intestinal mucosa and physiology in both mice and humans, it is completely unapproached, which influence the different microbiota could have on the development of the lung in early life.
The scientific literature and my early proof-of-principle preliminary results appeared to support a role for microbiota manipulation in lung development, which could possibly intercept or ameliorate lung diseases. With the “ProLung” project, I wanted to show causation by transferring the changed lung phenotype with the microbiota between mice. I wanted to reveal underlying changes to lung gene expression, circulation growth factors and show how it could affect breathing patterns using whole body plethysmography, that records different breathing parameters over time.
The overall objectives of the project:
Objective 1) To identify the timing of the effect of microbiota on lung development
Objective 2) To identify the mechanism behind the effect of microbiota on lung development
Objective 3) To quantify enhanced lung function in a relevant lung disease model of BPD
The scientific literature and my early proof-of-principle preliminary results appeared to support a role for microbiota manipulation in lung development, which could possibly intercept or ameliorate lung diseases. With the “ProLung” project, I wanted to show causation by transferring the changed lung phenotype with the microbiota between mice. I wanted to reveal underlying changes to lung gene expression, circulation growth factors and show how it could affect breathing patterns using whole body plethysmography, that records different breathing parameters over time.
The overall objectives of the project:
Objective 1) To identify the timing of the effect of microbiota on lung development
Objective 2) To identify the mechanism behind the effect of microbiota on lung development
Objective 3) To quantify enhanced lung function in a relevant lung disease model of BPD
The work performed and the main results: In order to identify the timing of the effect of microbiota on lung development (Objective 1), I setup a larger and repeat experiment to elucidate effect the probiotic exposure of Dams through pregnancy and weaning periods. I added a cross-breeding element, by redistributing pups at birth between dams, in such a way that I would end up with four groups of offspring with different timing of exposure to Dams microbiome with and without probiotic bacteria. (1.PRO-PRO 2.PRO-Control 3.Control-PRO and 4.Control-Control). I measured lung physiology by stereology and breathing patterns of these four groups of offspring. The results show that breathing patterns are indeed influenced by timing of exposure but was unable to repeat the physiological changes by stereology results from the preliminary experiments.
In order to identify the mechanism behind the effect of microbiota on lung development (Objective 2), I performed microbiota transfer experiment, where pregnant mice completely free of bacteria (Germ-free(GF)), were exposed to become: either Controls (no exposure), Monoculture (exposed to the single probiotics strain of Bifidobacteria) or Full Microbiome (exposed to a full microbiome composition from Dams used in Objective 1). The offspring of these dams was then tested for, milk microbiome and milk components of the Dams, lung-gene-expression and specific immunesystem alterations of the offspring at age of 10days (when they are still obligatory fed by mothers milk) and breathing patterns age of 21 days. Results so far, shows small changes to the immunesystem, gene expression and breathing patterns according to the direct exposure of the dams and indirect though milk and housing in early life. Furthermore, we are currently mapping fluctuations to the pregnancy gut microbiome of the dams according to exposure throughout the pregnancy period. These data and the milk analysis are still being compiled.
The final objective (Objective 3) was to apply the result to a relevant lung disease model of BPD based on O2 exposure. This was never attempted, as some of the questions were simultaneously addressed and published by my research collaborators and leading scientists at The University of Michigan. Their results show that the microbiome indeed are influenced by O2 exposure and has an influence on lung damage in BPD in correlations to the lung microbiome of the mice.
In order to identify the mechanism behind the effect of microbiota on lung development (Objective 2), I performed microbiota transfer experiment, where pregnant mice completely free of bacteria (Germ-free(GF)), were exposed to become: either Controls (no exposure), Monoculture (exposed to the single probiotics strain of Bifidobacteria) or Full Microbiome (exposed to a full microbiome composition from Dams used in Objective 1). The offspring of these dams was then tested for, milk microbiome and milk components of the Dams, lung-gene-expression and specific immunesystem alterations of the offspring at age of 10days (when they are still obligatory fed by mothers milk) and breathing patterns age of 21 days. Results so far, shows small changes to the immunesystem, gene expression and breathing patterns according to the direct exposure of the dams and indirect though milk and housing in early life. Furthermore, we are currently mapping fluctuations to the pregnancy gut microbiome of the dams according to exposure throughout the pregnancy period. These data and the milk analysis are still being compiled.
The final objective (Objective 3) was to apply the result to a relevant lung disease model of BPD based on O2 exposure. This was never attempted, as some of the questions were simultaneously addressed and published by my research collaborators and leading scientists at The University of Michigan. Their results show that the microbiome indeed are influenced by O2 exposure and has an influence on lung damage in BPD in correlations to the lung microbiome of the mice.
The progress of the project should be seen in the light of the rapidly evolving field. The results have built on the idea that the microbiome influences development and breathing patterns. Furthermore the results show that the timing of the microbiome influence on breathing patterns are primarily after birth. Differences in Lung gene expression at day 10 of life are primarily driven by sex, but further analysis are needed. Understanding how the microbiome of the mother transfers to offspring, with a focus on lung has the potential to changes our view on certain lung diseases (especially BPD) and medical practices surrounding preagnancy and early life of children.