Adipocyte metabolic state regulates glial phagocytic function.

Area of Science:

• Metabolic regulation
• Neuroscience
• Adipose tissue biology

Background:

• Excess dietary sugar negatively impacts organismal metabolism and health.
• The influence of adipose tissue metabolic adaptations on other organs, particularly the brain, is not well understood.

Purpose of the Study:

• To investigate how high-sugar diet-induced metabolic changes in Drosophila adipose tissue affect brain function and glial cells.
• To identify the molecular mechanisms linking adipocyte metabolism to neuroprotection.

Main Methods:

• Utilized Drosophila melanogaster as a model organism.
• Administered a high-sugar diet (HSD) to assess metabolic shifts in adipocytes.
• Performed cell-specific genetic manipulations in adipocytes targeting glycolysis, lipid metabolism, and mitochondrial dynamics.
• Analyzed Draper expression in brain ensheathing glia.
• Investigated the role of adipocyte-derived ApoB lipoproteins and their receptor LpR1 in glia.

Main Results:

• HSD reduced adipocyte glycolysis and mitochondrial pyruvate uptake, promoting fatty acid oxidation and ketogenesis.
• Metabolic shifts in adipocytes triggered mitochondrial oxidation and elevated antioxidant responses.
• Adipocyte manipulations non-autonomously modulated Draper expression in brain ensheathing glia.
• Adipocyte-derived ApoB lipoproteins, acting via LpR1, are essential for maintaining basal Draper levels and glial phagocytic activity.
• Impaired ApoB or LpR1 function reduced glial clearance of degenerating neuronal debris post-injury.

Conclusions:

• Dietary sugar induces metabolic adaptations in adipose tissue that influence brain health.
• Adipocyte-derived ApoB lipoproteins act as systemic mediators linking metabolic status to neuroprotective glial functions.
• This study highlights a novel pathway where metabolic state impacts glial phagocytosis and neuronal debris clearance.