Brain Synapse Energy Linked to Triglyceride Metabolism
Publication Title: Triglycerides are an important fuel reserve for synapse function in the brain
Summary
- Question
- This study examined the role of triglycerides (a type of fat stored in lipid droplets) in supporting brain function. Specifically, the researchers investigated how neurons utilize triglycerides stored in lipid droplets at synaptic terminals (the communication points between neurons) to produce energy and sustain their function.
- Why it Matters
- Understanding how neurons generate energy is critical for addressing neurological disorders and cognitive decline. Traditionally, neurons were thought to rely solely on glucose as a fuel source, but this study challenges that assumption by revealing the importance of triglycerides. These findings could provide new insights into conditions such as hereditary spastic paraplegia, where lipid metabolism in neurons is impaired, and offer potential avenues for therapeutic interventions in neurodegenerative diseases.
- Methods
- The researchers used a combination of genetic manipulation, chemical inhibitors, and imaging techniques to study lipid droplet metabolism in neurons from mice and rats. They observed how blocking key enzymes and transporters affected lipid droplet accumulation and energy production in neurons under different conditions. They also performed experiments to assess how neurons respond to fuel deprivation and analyzed lipid content using advanced biochemical methods.
- Key Findings
- The researchers found that neurons actively use triglycerides stored in lipid droplets to generate energy, particularly at synaptic terminals during electrical activity. Blocking the enzyme DDHD2, which breaks down triglycerides, led to lipid droplet accumulation and impaired neuronal energy production. Additionally, inhibiting fatty acid transport into mitochondria—the cell's energy powerhouse—caused neurons to lose their ability to sustain energy-dependent processes, such as synaptic vesicle recycling, in the absence of glucose.
- Implications
- These findings reveal a previously unrecognized mechanism by which neurons maintain energy balance, highlighting the importance of triglyceride metabolism for synaptic function. This research could help explain why disruptions in lipid metabolism are linked to cognitive impairment and neurodegenerative disorders. It also suggests that therapies targeting lipid metabolism could improve brain function under conditions of energy stress, such as during aging or in metabolic diseases.
- Next Steps
- The authors suggest further research to explore the sources of fatty acids used by neurons and how they are transported into the cell. Investigating the relationship between neuronal lipid metabolism and electrical activity could provide deeper insights into brain bioenergetics. Additionally, they propose studying how lipid metabolism changes in aging brains and its potential impact on cognitive function.
- Funding Information
- This research was supported by the National Institutes of Health (awards NS036942, NS11739, and F31 CA278383). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Additional support was provided by Aligning Science Across Parkinson’s (ASAP-000580 and ASAP-024404) through the Michael J. Fox Foundation for Parkinson’s Research, and a KL2 award to K.N.R. from the Rockefeller University. Yale University also provided funding and support for this research.
Full Citation
Kumar M, Wu Y, Knapp J, Pontius C, Park D, Witte R, McAllister R, Gupta K, Rajagopalan K, De Camilli P, Ryan T. Triglycerides are an important fuel reserve for synapse function in the brain. Nature Metabolism 2025, 7: 1392-1403. PMID: 40595405, PMCID: PMC12286841, DOI: 10.1038/s42255-025-01321-x.
Authors
Mukesh Kumar
First AuthorTimothy A. Ryan
Last Author
Yale School of Medicine Authors
Other Authors
Research Themes
Keywords
Concepts
- Lipid droplets;
- Fatty acids;
- Mitochondrial ATP production;
- Function in vivo;
- Activity-dependent fashion;
- Nerve terminals;
- ATP production;
- Neuronal function in vivo;
- Synapse function;
- Adult male mice;
- Triglyceride lipase;
- In vivo neurons;
- DDHD2;
- Neuronal bioenergetics;
- Male mice;
- Acute block;
- Electrical silence;
- Metabolic support;
- Neurons;
- Nerve;
- Fuel reserves;
- Electrical activity;
- Mitochondria;
- Cognitive function;
- Bioenergetics
Media
Schematic representation of the experimental paradigm dissociated hippocampal neurons expressing vGlut1–pHluorin were perfused with indicated media for 5 min followed by AP firing at 1 min intervals.