Opposing GIPR brainstem circuits differentially control feeding behaviour

Area of Science:

• Neuroscience
• Endocrinology
• Obesity Research

Background:

• Central glucose-dependent insulinotropic polypeptide receptor (GIPR) signaling is crucial for GIP-based obesity treatments.
• The specific roles of different GIPR neuron subpopulations in appetite regulation are not fully understood.

Purpose of the Study:

• To investigate the opposing roles of GIPR neurons in the area postrema (AP) and nucleus tractus solitarius (NTS) in controlling ingestion.
• To determine the necessity of GIPR expression in AP and NTS neurons for appetite suppression during GIPR antagonism.
• To explore the distinct gut-brain circuits and obesity-driven remodeling sensitivities of GIPR neurons in the AP and NTS.

Main Methods:

• Utilized genetic manipulation and neuronal tracing techniques in rodent models.
• Investigated GIPR neuron activity in the AP and NTS.
• Examined the effects of GIPR antagonism on appetite regulation.

Main Results:

• GIPR neurons in the AP (GIPR^AP) dampen post-ingestive satiation, leading to hyperphagia.
• GIPR neurons in the NTS (GIPR^NTS) exhibit anorectic effects.
• GIPR expression in AP neurons, but not NTS neurons, is essential for appetite suppression following GIPR antagonism.
• GIPR neurons in the AP and NTS are integrated into distinct gut-brain circuits and show differential sensitivity to obesity-induced remodeling.

Conclusions:

• GIPR neurons in the AP and NTS exert opposing control over appetite, with AP neurons promoting feeding and NTS neurons suppressing it.
• These findings provide a framework for understanding the mechanisms underlying GIPR agonist and antagonist therapies for weight loss.
• Targeting specific GIPR neuron subpopulations may offer refined strategies for obesity treatment.