Angiotensin AT(1A) receptor signal switching in Agouti-related peptide neurons mediates metabolic rate adaptation during obesity

Resting metabolic rate (RMR) adaptation occurs during obesity and is hypothesized to contribute to failed weight management. Angiotensin II (Ang-II) type 1 (AT1A) receptors in Agouti-related peptide (AgRP) neurons contribute to the integrative control of RMR, and deletion of AT1A from AgRP neurons causes RMR adapta-tion. Extracellular patch-clamp recordings identify distinct cellular responses of individual AgRP neurons from lean mice to Ang-II: no response, inhibition via AT1A and Gai, or stimulation via Ang-II type 2 (AT2) recep-tors and Gaq. Following diet-induced obesity, a subset of Ang-II/AT1A-inhibited AgRP neurons undergo a spontaneous G-protein signal switch,whereby AT1A stop inhibiting the cell via Gai and instead begin stimulating the cell via Gaq. DREADD-mediated activation of Gai, but not Gaq, in AT1A-expressing AgRP cells stimulates RMR in lean and obese mice. Thus, loss of AT1A-Gai coupling within the AT1A-expressing AgRP neuron subtype represents a molecular mechanism contributing to RMR adaptation.

Automated summary

This study found that during obesity, the inhibitory effect of AT1A receptors on AgRP neurons is weakened, leading to metabolic adaptation, which may be a contributing factor to failed weight management.