Periodic Reporting for period 1 - miVaO (Microbiota mediating Vagal communication in Obesity)
Reporting period: 2018-12-01 to 2020-11-30
In the last decade gut microbiota has been identified as a new factor involved obesity and metabolic health. Nevertheless, further investigations are required to identify key intestinal bacteria and their mode of action on multiple pathways regulating host metabolism.
The project miVaO aimed to deciphering the role the gut microbiota plays in the regulation of nutrient sensory transmission from the vagal innervations of the gastrointestinal tract to the brain (nutrient sensing) to ultimately control energy homeostasis after a meal. Through in vitro and in vivo studies and omic approaches, miVaO has contributed to: 1) the identification of key intestinal bacteria that modulate sensory neurons and induce anti-diabetic effects in a rodent model of diet-induced obesity and 2) the demonstration that the sensory afferent neurons are required to control energy homeostasis.
To further investigate the bidirectional relationship between gut microbiota and vagal afferents as a key component of the gut-brain axis that controls food intake and energy balance, we generated a vagal afferent deficient rodent model through genetic tools. We demonstrated that, in response to an obesogenic diet, the specific ablation of these neurons induced a partial resistance to gain weight, improved glucose tolerance, exacerbated the fasting/refeeding-induced body weight variations and impaired the long and short-term control of food intake and the intestinal immunity. Some of these effects depend on gender. The analysis of fecal samples through metabolomics and 16S rRNA amplicons is ongoing to identify vagal afferent-dependent diurnal oscillations of metabolites and/or bacterial taxa related to feeding patterns. This will help to identify intestinal bacteria and metabolites involved in vagal afferent-mediated nutrient sensing in obesity.
The main results of the action have been exposed to the scientific community by attending to conferences organized by the Spanish Society for the study of Obesity, the European Society of Neurogastroenterology and Motility, the Instituto Gulbenkian de Ciência, the Galician Society of Endocrinology, Nutrition and Metabolism and to meetings organized by the host institution (IATA-CSIC). The research has been also communicated to the general public by participating in different events including the open day event in the host institution and talks to students in the international day of Woman and Girl in Science.