α-Synuclein Regulates Peripheral Insulin Secretion and Glucose Transport

Area of Science:

• Neuroscience
• Metabolic Research
• Cell Biology

Background:

• Population studies link type 2 diabetes (T2D) and Parkinson's disease (PD), noting increased PD risk in T2D patients.
• Parkinson's disease involves aggregated alpha-synuclein (α-syn) impacting neuronal viability.
• α-syn is also present in pancreatic islets and skeletal muscle, crucial for glucose regulation.

Purpose of the Study:

• To investigate the functional role of α-syn in pancreatic islet and skeletal muscle glucose regulation.
• To determine the impact of α-syn on glucose tolerance, insulin sensitivity, and insulin secretion.

Main Methods:

• Mice models were used: lacking, overexpressing, or injected with α-syn.
• Glucose and insulin tolerance tests were performed.
• Insulin secretion and GLUT4 translocation in myotubes were characterized.

Main Results:

• Mice lacking α-syn exhibited glucose intolerance, insulin resistance, and reduced insulin secretion.
• Mice overexpressing α-syn showed improved glucose tolerance, insulin sensitivity, and enhanced insulin secretion.
• α-syn monomers increased cell surface GLUT4 by reducing endocytosis, impacting glucose transport.

Conclusions:

• α-syn significantly modulates pancreatic beta cell function.
• α-syn plays a pivotal role in regulating glucose transport in peripheral tissues.
• These findings highlight α-syn's importance in maintaining normal glucose homeostasis.