The DGAT1 gene (Diacylglycerol O-Acyltransferase 1) encodes an essential enzyme responsible for the final step in triglyceride synthesis, catalyzing the acyl-CoA-dependent acylation of diacylglycerol to form triacylglycerol (TAG). DGAT1 belongs to the acyltransferase family and plays a critical role in lipid metabolism throughout the body. While traditionally studied in the context of metabolic diseases such as obesity and insulin resistance, emerging research reveals that DGAT1 also plays important roles in the central nervous system (CNS), particularly in neurons where lipid homeostasis is essential for synaptic function, membrane integrity, and neuronal survival[@cases2001][@buono2006].
Dysregulation of neuronal lipid metabolism has been increasingly recognized as a contributing factor in neurodegenerative diseases including Alzheimer's disease (AD) and Parkinson's disease (PD). DGAT1-mediated triglyceride synthesis and lipid droplet formation in neurons may influence amyloid-beta (Aβ) aggregation, tau phosphorylation, and α-synuclein pathology. Consequently, DGAT1 has emerged as a potential therapeutic target for neurodegenerative disease modification[@chen2013][@chan2016].
| Diacylglycerol O-Acyltransferase 1 | |
|---|---|
| Gene Symbol | DGAT1 |
| Full Name | Diacylglycerol O-Acyltransferase 1 |
| Chromosome | 8q24.3 |
| NCBI Gene ID | [8694](https://www.ncbi.nlm.nih.gov/gene/8694) |
| OMIM | 604035 |
| Ensembl ID | ENSG00000185088 |
| UniProt ID | [Q9H5Z1](https://www.uniprot.org/uniprot/Q9H5Z1) |
| Associated Diseases | Alzheimer's Disease, Parkinson's Disease, Metabolic Syndrome, Obesity, Lipid Storage Disorders |
The DGAT1 gene is located on chromosome 8q24.3 and spans approximately 16 kilobases. It consists of 17 exons that encode a protein of approximately 460 amino acids.
| Property | Value |
|---|---|
| Gene Symbol | DGAT1 |
| Chromosomal Location | 8q24.3 |
| NCBI Gene ID | 8694 |
| Ensembl ID | ENSG00000185088 |
| UniProt | Q9H5Z1 |
| RefSeq | NM_001122998 |
The DGAT1 protein contains several key structural features:
DGAT1 localizes primarily to the ER membrane, where it accesses its substrates in the ER lumen and cytosol. It can also associate with lipid droplets under certain conditions[@buono2006][@liu2012].
DGAT1 catalyzes the final and committed step in triglyceride biosynthesis:
Diacylglycerol + Acyl-CoA → Triacylglycerol + CoA
This reaction sequesters fatty acids in theirStorage form (triglycerides) within lipid droplets, protecting cells from lipotoxicity associated with excess free fatty acids.
DGAT1 plays a critical role in lipid droplet biogenesis:
In non-adipose tissues, including the brain, lipid droplets serve important functions in buffering lipid species and providing energy during stress[@zhang2018].
In neurons, DGAT1 and lipid droplets serve several essential functions:
Studies in neuronal cell culture demonstrate that DGAT1 expression is dynamically regulated during synaptic activity, with increased TAG synthesis following prolonged neuronal activation[@li2020].
DGAT1 is expressed in multiple cell types within the CNS:
High expression is observed in:
DGAT1 is implicated in AD through multiple mechanisms:
Amyloid Metabolism: Altered lipid metabolism affects amyloid precursor protein (APP) processing and Aβ secretion. DGAT1 inhibition reduces Aβ production in cellular models, suggesting that TAG synthesis may influence amyloidogenic processing[@chen2013].
Lipid Droplet Accumulation: Post-mortem AD brain shows increased lipid droplet accumulation in neurons and glia. DGAT1-mediated TAG synthesis contributes to this accumulation, which may impair cellular function and promote neurodegeneration[@zhang2018].
Synaptic Dysfunction: Neuronal lipid metabolism is essential for synaptic vesicle cycling and neurotransmitter release. DGAT1 deficiency or inhibition disrupts these processes, potentially contributing to synaptic loss in AD[@li2020].
Therapeutic Potential: DGAT1 inhibitors reduce Aβ toxicity in vitro and improve cognitive function in AD mouse models. These findings support continued investigation of DGAT1 as a therapeutic target[@zhao2019][@rodriguez2021].
DGAT1 contributes to PD pathophysiology:
α-Synuclein Pathology: Lipid droplets interact with α-synuclein and may influence its aggregation. DGAT1-mediated lipid droplet formation may either protect against or promote α-synuclein pathology depending on context[@villanueva2019].
Dopaminergic Neuron Vulnerability: The substantia nigra has high lipid metabolic demands due to ongoing dopamine synthesis. DGAT1-mediated lipid homeostasis is essential for maintaining dopaminergic neuron health.
Oxidative Stress: Lipid droplets serve as both sinks and sources of oxidative stress. DGAT1 inhibition reduces oxidative damage in neuronal models, potentially through altered lipid droplet dynamics[@yang2020].
Beyond neurodegeneration, DGAT1 is central to systemic metabolic disease:
Obesity: DGAT1 deficiency or inhibition reduces adiposity in mouse models
Insulin Resistance: Altered TAG metabolism affects insulin signaling
Fatty Liver: DGAT1 inhibition reduces hepatic steatosis
These metabolic effects may indirectly influence neurodegeneration through altered systemic inflammation and cardiovascular health.
DGAT1 intersects with multiple lipid metabolic pathways:
| Pathway | Interaction |
|---|---|
| Fatty Acid Synthesis | Provides substrates for TAG synthesis |
| Phospholipid Synthesis | Competes for DAG precursors |
| Cholesterol Esterification | Shares substrates (DAG) |
| Ceramide Synthesis | Cross-talk with sphingolipid pathways |
| Autophagy | Lipid droplets are targets of lipophagy |
DGAT1 expression is regulated by several transcription factors:
DGAT1 activity is modulated by:
Several DGAT1 inhibitors have been developed for metabolic disease and are being repurposed for neurodegeneration:
| Compound | Target | Stage | Key Findings |
|---|---|---|---|
| T863 | DGAT1 | Preclinical | Reduces Aβ toxicity[@zhao2019] |
| JNJ-37619832 | DGAT1 | Research | Improves cognitive function |
| PF-04620110 | DGAT1 | Clinical (obesity) | Well-tolerated in humans |
Developing DGAT1-targeted therapies for neurodegenerative diseases presents several challenges:
Several factors favor DGAT1 as a therapeutic target: