Our latest publication on how polar lipids affect the pathology of Alzeimer’s disease:
Figure 1 : A DI TNC1 cells were treated with 1 µM Aβ peptide or 1 µg/µl LPS for 24 h and compared to untreated controls. qRT-PCR using rat ptafr specific primers and hmbs as housekeeping gene for normalization reveals a significant increase in ptafr gene expression after activation of astrocytes by LPS and Aβ (one-way ANOVA, p<0.0001; Tukey posthoc test: Ctrl vs. LPS p<0.001; Ctrl vs. Aβ p=0.0235; Aβ vs. LPS p<0.001, n=3-4). B, C Immunocytochemistry confirms the increase in protein level. 24 h after treatment with 1 µM Aβ peptide, PTAFR fluorescent signals are significantly increased (t-test, p=0.0008, n=15). (AFU: Absolute Fluorescence Units). C Exemplary images of PTAFR fluorescence after treatment. Scale bar = 30 μm. D Western blotting further confirms an increase of PTAFR on protein level after exposure to LPS and Aβ (one-way ANOVA, p<0.0001; Tukey posthoc test: Ctrl vs. LPS p=0.0145; Ctrl vs. Aβ p=0.0100; Aβ vs. LPS p=0.00100, n=3). Tubulin was used as a housekeeping protein for normalization. The exposure time was reduced for the Aβ condition to avoid overexposure of the PTAFR band
Background
Pro-inflammatory processes triggered by the accumulation of extracellular amyloid beta (Aβ) peptides are a well-described pathology in Alzheimer’s disease (AD). Activated astrocytes surrounding Aβ plaques contribute to inflammation by secreting proinflammatory factors. While astrocytes may phagocytize Aβ and contribute to Aβ clearance, reactive astrocytes may also increase Aβ production. Therefore, identifying factors that can attenuate astrocyte activation and neuroinflammation and how these factors influence pro-inflammatory pathways is important for developing therapeutic and preventive strategies in AD. Here, we identify the platelet-activating factor receptor (PTAFR) pathway as a key mediator of astrocyte activation. Intriguingly, several polar lipids (PLs) have exhibited anti-inflammatory protective properties outside the central nervous system through their inhibitory effect on the PTAFR pathway. Thus, we additionally investigated whether different PLs also exert inhibitory effects on the PAF pathway in astrocytes and whether their presence influences astrocytic pro-inflammatory signaling and known AD pathologies in vitro.
Methods
PLs from salmon and yogurt were extracted using novel food-grade techniques and their fatty acid profile was determined using LC/MS. The effect of PLs on parameters such as astrocyte activation and generation of oxygen species (ROS) was assessed. Additionally, effects of the secretome of astrocytes treated with these polar lipids on aged neurons was measured.
Results
We show that PLs obtained from salmon and yogurt lower astrocyte activation, the generation of reactive oxygen species (ROS), and extracellular Aβ accumulation. Cell health of neurons exposed to the secretome of astrocytes treated with salmon-derived PLs and Aβ was less affected than those treated with astrocytes exposed to Aβ only.
Conclusion
Our results highlight a novel underlying mechanism, why consuming PL-rich foods such as fish and dairy may reduce the risk of developing dementia and associated disorders.