PROJECT SUMMARY The cardiometabolic disease burden is increasing in the United States. The atrial natriuretic peptide (ANP) hormone contributes to the regulation of glucose utilization, energy homeostasis and is a major determinant of cardiometabolic health. We have demonstrated that a common genetic variant in the ANP gene (rs5068) is associated with higher ANP levels and a more favorable cardiometabolic profile. We have also identified that microRNA-425 (miR-425) decreases the production of ANP. The favorable genetic variant (rs5068) prevents the binding of miR-425 and ensures adequate ANP production. Thus, miR-425 acts only among those with low ANP genotype, i.e., those without the rs5068 genetic variant. We have also demonstrated that an oral glucose challenge reduces ANP levels, whereas an exercise challenge increases ANP levels. However, the impact of the ANP genotype on the ANP response to glucose challenge and exercise challenge has not been previously examined. We have demonstrated that miR-425 is glucose-responsive and may regulate the ANP response to metabolic perturbations. The response of miR-425 to glucose challenge, exercise challenge, and its relationship with energy expenditure (EE) is not known in humans. We hypothesize that individuals with low ANP genotype will (1) have a greater suppression of ANP by glucose challenge, (2) have lower resting and exercise EE, and (3) demonstrate the responsiveness of miR-425 to metabolic perturbations (glucose challenge and exercise challenge). We propose to conduct a genotype-guided study by performing detailed metabolic profiling among individuals with high and low ANP genotypes. In our Aim 1, we will enroll 200 healthy adults (50 with high ANP genotype and 150 with low ANP genotype), and we will assess the difference in response of MRproANP to a glucose challenge by genotype groups. We will also assess the change in the glucose and insulin levels subsequent to glucose challenge between high and low ANP genotype groups. In Aim 2, we will assess the difference in EE (during rest and during exercise) between the two genotype groups. We will also assess the difference between the two genotype groups in terms of the response of ANP, glucose, insulin, and markers of fat breakdown to the standardized exercise challenge. In Aim 3, we will assess if there is a change in miR-425 expression after glucose and exercise challenge among those with low ANP genotype. We will also assess the association of change in miR-425 expression with the change in MRproANP, glucose, and insulin levels following respective metabolic perturbations (glucose challenge and exercise challenge). The detailed metabolic profiling of participants based on their ANP genotype will provide insights into the role of the ANP system in the regulation of cardiometabolic health and generate evidence supporting the biological basis for developing RNA-based novel treatment approaches to prevent and treat cardiometabolic diseases.