Nutrient-Sensing in Neurons: A Distinct Metabolic Pathway
Researchers from the University of Cambridge have published a review examining nutrient-sensing mechanisms in neurons, highlighting a proposed metabolic pathway that differs from the canonical mechanisms studied in other cell types.
Summary
The review, titled "Nutrient-sensing and mTORC1 regulation in neuronal homeostasis: from metabolic signaling to neurodegeneration," was published in EXO – Beyond the Cell (DOI:10.70401/EXO.2026.0009). It was authored by Sung Min Son, Weining Li, and David C. Rubinsztein.
The review presents evidence that neurons and other cell types may regulate mTORC1 signaling through a leucine-derived acetyl-coenzyme A (AcCoA) pathway, rather than the Sestrin2-mediated leucine-sensing pathway that has been extensively studied in HEK293 cells.
Proposed Mechanism
According to the review, the proposed pathway functions as follows:
- Leucine is converted into acetyl-coenzyme A (AcCoA).
- AcCoA activates the acetyltransferase p300.
- p300 acetylates Raptor, a component of the mTORC1 complex.
- This acetylation activates mTORC1 signaling.
The researchers noted that "neuronal nutrient sensing may have differences to what is seen in HEK293 cells, which have been used extensively in the previous literature."
Implications for Neurodegenerative Disease
The review cites evidence linking chronic overactivation of mTORC1 to impaired autophagy and toxic protein accumulation in neurodegenerative diseases, including Alzheimer's, Parkinson's, Huntington's, and amyotrophic lateral sclerosis (ALS).
Neurons, being long-lived and unable to divide, rely on autophagy to clear damaged proteins. Converging metabolic and inflammatory pathways have been implicated in pathological mTORC1 activation. The review mentions abnormal AcCoA accumulation and inflammatory signaling through CCR5 as potential contributors to autophagy defects in neurodegenerative disease models.
Proposed Therapeutic Strategies
Rather than directly suppressing mTORC1, the review suggests alternative therapeutic approaches that target upstream metabolic nodes:
- Modulation of AcCoA production
- Regulation of p300 acetylation activity
- Targeting inflammatory-metabolic crosstalk pathways, such as CCR5 signaling