Obesity is a severe public health challenge globally and a significant determinant of disability and death. According to WHO, overweight and obesity have reached epidemic proportions in the European region, affecting almost 60% of adults and one in three school-aged children. Obesity substantially reduces health and well-being and, consequently, accounts for considerable costs that place a strain on national healthcare systems, economic productivity, and social resources. Besides, people with obesity often suffer from weight stigma that damages mental health and causes discrimination. Accordingly, addressing obesity is a priority for achieving the Sustainable Development Goals. In this sense, several policy frameworks and action plans to halt the rise in obesity have been set out; however, there have been consistent increases in the prevalence of overweight and obesity in the European Region, and no Member State is on track to reach the target of halting the rise in obesity by 2025. There is thus an urgent need to better understand the interplay between environmental obesity drivers (e.g. unhealthy diets) and individual response to such drivers (e.g. the response mediated by gut microbiota), to develop more effective interventions to combat obesity at population and individual levels.
To overcome the pandemic worldwide evolution of obesity and cardiometabolic diseases, research has increasingly focused its attention on interventions targeting the gut microbiota. These strategies arise from the increasing evidence demonstrating that alterations in the microbiota influence adiposity, insulin resistance, and other hallmarks of obesity and metabolic syndrome. Nonetheless, the key bacteria relevant for obesity and the precise mechanisms by which they contribute to define metabolic phenotypes are unknown. Growing evidence points to the intestinal immune system as an important contributor to systemic inflammation associated with obesity. The intestine is the largest immune organ of the body, and is inhabited by trillions of bacteria that, in turn, influence immune function. It is also the first to be exposed to the effects of dietary patterns, which can modulate the gut microbiota. Thus, the gut microbiota could be essential to moderate or aggravate the response of the intestinal immune system to diet, influencing metabolic homeostasis at both intestinal and peripheral levels.
The aim of the EU-funded MicroILCs project was to identify the key determinants of the gut ecosystem for the immune responses of the innate lymphoid cells (ILCs) in particular. Specifically, we have assessed the role of the microbiota in regulating ILCs as a possible driver of gut microbiota-mediated effects on obesity and metabolic dysfunction and, thereby, identified effective microbiota-based interventions to combat obesity.
