Abstract
Cholesterol is crucial for the proper functioning of eukaryotic cells, especially neurons, which rely on cholesterol to maintain their complex structure and facilitate synaptic transmission. However, brain cells are isolated from peripheral cholesterol by the blood-brain barrier and mature neurons primarily uptake the cholesterol synthesized by astrocytes for proper function. This study aimed to investigate the effect of aging on cholesterol trafficking in astrocytes and its delivery to neurons. We found that aged astrocytes accumulated high levels of cholesterol in the lysosomal compartment, and this cholesterol buildup can be attributed to the simultaneous occurrence of two events: decreased levels of the ABCA1 transporter, which impairs ApoE-cholesterol export from astrocytes, and reduced expression of NPC1, which hinders cholesterol release from lysosomes. We show that these two events are accompanied by increased microR-33 in aged astrocytes, which targets ABCA1 and NPC1. In addition, we demonstrate that the microR-33 increase is triggered by oxidative stress, one of the hallmarks of aging. By coculture experiments, we show that cholesterol accumulation in astrocytes impairs the cholesterol delivery from astrocytes to neurons. Remarkably, we found that this altered transport of cholesterol could be alleviated through treatment with endocannabinoids as well as cannabidiol or CBD. Finally, according to data demonstrating that aged astrocytes develop an A1 phenotype, we found that cholesterol buildup is also observed in reactive C3+ astrocytes. Given that reduced neuronal cholesterol affects synaptic plasticity, the ability of cannabinoids to restore cholesterol transport from aged astrocytes to neurons holds significant implications in aging and inflammation.
Keywords: aging, astrocytes, cannabinoids, cholesterol, trafficking
© 2024 Wiley Periodicals LLC.
References
REFERENCES
-
- Abe, M., Makino, A., Hullin‐Matsuda, F., Kamijo, K., Ohno‐Iwashita, Y., Hanada, K., Mizuno, H., Miyawaki, A., & Kobayashi, T. (2012). A role for sphingomyelin‐rich lipid domains in the accumulation of phosphatidylinositol‐4,5‐bisphosphate to the cleavage furrow during cytokinesis. Molecular and Cellular Biology, 32, 1396–1407. https://doi.org/10.1128/MCB.06113-11
-
- Ali, T., Badshah, H., Kim, T. H., & Kim, M. O. (2015). Melatonin attenuates D‐galactose‐induced memory impairment, neuroinflammation and neurodegeneration via RAGE/NF‐K B/JNK signaling pathway in aging mouse model. Journal of Pineal Research, 58(1), 71–85. https://doi.org/10.1111/jpi.12194
-
- Azman, K. F., & Zakaria, R. (2019). D‐Galactose‐induced accelerated aging model: An overview. Biogerontology, 20(6), 763–782. https://doi.org/10.1007/s10522-019-09837-y
-
- Bartoll, A., Toledano‐Zaragoza, A., Casas, J., Guzmán, M., Schuchman, E. H., & Ledesma, M. D. (2020). Inhibition of fatty acid amide hydrolase prevents pathology in neurovisceral acid sphingomyelinase deficiency by rescuing defective endocannabinoid signaling. EMBO Molecular Medicine, 12(11), e11776. https://doi.org/10.15252/emmm.201911776
-
- Bilkei‐Gorzo, A., Albayram, O., Draffehn, A., Michel, K., Piyanova, A., Oppenheimer, H., Dvir‐Ginzberg, M., Rácz, I., Ulas, T., Imbeault, S., Bab, I., Schultze, J. L., & Zimmer, A. (2017). A chronic low dose of Δ9‐tetrahydrocannabinol (THC) restores cognitive function in old mice. Nature Medicine, 23(6), 782–787. https://doi.org/10.1038/nm.4311