CCK Response Deficiency in Synphilin-1 Transgenic Mice

Area of Science:

• Neuroscience
• Endocrinology
• Physiology

Background:

• Synphilin-1 (SP1) is a cytoplasmic protein previously linked to regulating food intake and body weight.
• Overexpression of SP1 in mouse brain neurons causes hyperphagia, characterized by larger meal sizes.
• The precise mechanisms by which SP1 influences feeding behavior remain unclear.

Purpose of the Study:

• To investigate the role of gut feedback signaling in SP1-mediated effects on food intake.
• To determine if SP1 impacts the response to peripheral gut hormones involved in appetite regulation.

Main Methods:

• Examined responses of wild-type (WT) and SP1 transgenic mice to peripheral administration of cholecystokinin (CCK), amylin, and exendin-4 (a GLP-1 receptor agonist).
• Assessed changes in food intake and CCK-induced c-Fos expression in the dorsal vagal complex.
• Compared responses between WT and SP1 transgenic mouse models.

Main Results:

• CCK administration significantly reduced glucose intake in WT mice but had no effect in SP1 transgenic mice.
• SP1 transgenic mice showed attenuated CCK-induced c-Fos expression in the dorsal vagal complex.
• Responses to amylin and exendin-4 were similar in both WT and SP1 transgenic mice, indicating a specific deficit in CCK signaling.

Conclusions:

• Synphilin-1 (SP1) protein deficiency in CCK response contributes to increased meal size and hyperphagia in transgenic mice.
• Altered gut feedback signaling, specifically impaired CCK response, is a key mechanism underlying SP1's effect on appetite regulation.