Connexin-43 Gap Junctions Are Responsible for the Hypothalamic Tanycyte-Coupled Network

Area of Science:

• Neuroscience
• Cell Biology
• Endocrinology

Background:

• Tanycytes, hypothalamic radial glia-like cells, sense glucose and modulate neuronal activity for feeding behavior control.
• Hypothalamic cell coupling, particularly through connexins, is essential for regulating brain glucose-induced insulin secretion.
• Tanycytes are considered potential hypothalamic neuronal precursors due to their location and shared characteristics with neuronal precursors in other neurogenic niches.

Purpose of the Study:

• To investigate the role of connexin 43 (Cx43) in tanycyte homotypic and panglial coupling within the hypothalamus.
• To determine the influence of Cx43 on hypothalamic cell proliferation and electrophysiological properties.

Main Methods:

• Utilized wild-type, Cx30 knockout, and Cx43/Cx30 double knockout mouse models.
• Employed the human GFAP (hGFAP)-enhanced green fluorescent protein (EGFP) transgenic mouse line to identify parenchymal-coupled cells.
• Performed electrophysiological recordings and assessed hypothalamic cell proliferation.

Main Results:

• Demonstrated that tanycytes form highly coupled networks primarily through Cx43, establishing a panglial network.
• Identified astrocytes as the main parenchymal-coupled cells.
• Observed altered electrophysiological parameters upon Cx43 genetic absence or pharmacological inhibition, and a significant decrease in hypothalamic proliferative cells in double knockout mice.

Conclusions:

• Cx43 is critical for tanycyte homotypic and panglial coupling, underscoring its importance in hypothalamic network formation.
• Cx43 function significantly impacts the proliferative potential of hypothalamic cells, suggesting a role in neurogenesis or cell maintenance.
• These findings elucidate the role of Cx43 in tanycyte function and hypothalamic cell proliferation, relevant to feeding behavior and potentially neurodevelopment.