Pharmacological administration of FGF21 reverses obesity through a parabrachial-projecting neuron population in the hindbrain

The obesity epidemic is associated with significant healthcare and economic burdens. Pharmacological administration of the endocrine hormone fibroblast growth factor 21 (FGF21) increases energy expenditure and reverses obesity. However, the central targets and neural pathways for these metabolic benefits remain elusive. Here, we demonstrate that β-klotho (KLB)-expressing neurons in the hindbrain, specifically the nucleus of the solitary tract (NTS) and area postrema (AP), are both necessary and sufficient for FGF21's effect on energy expenditure and weight loss. These pharmacological benefits are mediated largely by NTS/AP KLB-expressing neurons that project to the parabrachial nucleus (PBN) and not the hypothalamus. Our results provide insights into the central mechanisms of pharmacological FGF21 action to modulate energy homeostasis.