Glial Plasticity and Metabolic Stability After Knockdown of Astrocytic Cx43 in the Dorsal Vagal Complex

TL;DR

Reducing Cx43 in DVC astrocytes causes glial changes but not metabolic issues, suggesting a compensatory system preserves regulation.

Contribution

Shows that DVC glial plasticity compensates for Cx43 loss, maintaining metabolic and autonomic stability.

Findings

Cx43 knockdown in DVC astrocytes causes astrogliosis and microglial hyper-branching.

Energy metabolism remains largely unaffected despite Cx43 reduction in DVC astrocytes.

Dense astrocytic tiling and hyper-ramified microglia may buffer metabolic and autonomic regulation.

Abstract

What are the main findings?

Inactivation of Cx43 in DVC astrocytes leads to astrogliosis and microglial hyper-branching.

Energy metabolism is minimally affected by Cx43 knockdown in DVC astrocytes.

What is the implication of the main finding?

These results highlight the plasticity of DVC glial cells.

They suggest that this plasticity preserves metabolic and autonomic regulations.

Obesity causes millions of deaths each year due to metabolic complications, making it a major public health challenge. It results from a chronic imbalance between caloric intake and energy expenditure. Among central structures regulating energy balance, the dorsal vagal complex (DVC) integrates metabolic signals from energy stores and the gastrointestinal tract and coordinates autonomic responses. While historically overshadowed by a focus on neurons, the role of glial cells in regulating energy balance is now well established. Connexin 43 (Cx43) is a well-known protein expressed by astrocytes, playing a key role in glial and neuroglial communication. To investigate the role of astrocytic Cx43 within the DVC, where its expression is remarkably high, we specifically reduced it using an RNA interference approach. Although reduced Cx43 expression led to modified astrocyte and microglia morphology and phenotype, our analyses did not reveal significant changes in the animal’s metabolic phenotype under standard feeding conditions as well as under a high-fat, high-sugar diet. These results suggest that denser astrocytic tiling and hyper-ramified microglia may constitute a buffering system that preserves metabolic and autonomic outputs when a single connexin pathway fails.

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