The global obesity crisis and the limited success of current treatments underscore the need to identify novel regulatory pathways. While central administration of α-Klotho exerts anti-obesity effects Show more
The global obesity crisis and the limited success of current treatments underscore the need to identify novel regulatory pathways. While central administration of α-Klotho exerts anti-obesity effects in rodents through AgRP neurons, the intracellular signaling mechanisms that mediate this process remain undefined. To define the role of FGFR1 within the α-Klotho signaling pathway in AgRP neurons, we performed a targeted deletion of the receptor in adult mice using an AAV-mediated CRISPR/Cas9 system alongside transgenic models. Deletion of FGFR1 in AgRP neurons disrupted energy homeostasis, promoting weight gain induced by a high-fat diet. Electrophysiological recordings revealed that FGFR1 loss increased the intrinsic firing rate of AgRP neurons and abolished the suppressive effect of α-Klotho on their activity. At the molecular level, FGFR1 knockdown decreased phosphorylation of the transcription factor FOXO1 and elevated AgRP mRNA expression. Our results define a crucial FGFR1 signaling axis in AgRP neurons that coordinately regulates their electrical activity and peptide expression, thereby establishing FGFR1 as an essential regulator of energy homeostasis. Show less
The global obesity epidemic necessitates the identification of novel therapeutic targets. Although central administration of α-Klotho improves metabolic function in rodents, its precise mechanisms of Show more
The global obesity epidemic necessitates the identification of novel therapeutic targets. Although central administration of α-Klotho improves metabolic function in rodents, its precise mechanisms of action remain unclear. Since α-Klotho signals through fibroblast growth factor receptors (FGFRs), we hypothesized that FGFR1 within specific hypothalamic neuronal populations is critical for maintaining metabolic homeostasis. We investigated the metabolic role of FGFR1 in the arcuate nucleus of adult mice using an adeno-associated virus (AAV)-mediated CRISPR/Cas9 system, in conjunction with transgenic models, to achieve cell-type-specific knockout of FGFR1 in mature glutamatergic, gamma-aminobutyric acid (GABA)ergic, and agouti-related peptide (AgRP) neurons. We found that FGFR1 governs distinct metabolic functions in different neuronal populations. Conditional deletion of FGFR1 in glutamatergic neurons impaired glucose tolerance. In contrast, its ablation in GABAergic neurons induced a severe energy imbalance, resulting in obesity characterized by significant weight gain and adiposity. Notably, AgRP neuron-specific deletion of FGFR1 recapitulated this obese phenotype. Furthermore, the loss of FGFR1 in AgRP neurons disrupted α-Klotho signaling, preventing its ability to modulate AgRP neuron activity and abolishing its beneficial effects on glucose and energy metabolism. Our results establish FGFR1 in hypothalamic neurons as an essential component of the pathway through which α-Klotho regulates systemic energy balance. These findings identify hypothalamic FGFR1 as a critical molecular target for developing anti-obesity therapies. Show less