University of Hawai'i at Manoa, Hawaii, United States
Disclosure(s):
Radha Raman Raj, MS: No relevant financial relationship(s) with ineligible companies to disclose.
Objectives: Oxidative stress disrupts homeostasis of adipocytes. Ferroptosis is an iron-mediated cell death induced by reactive oxygen species causing lipid peroxidation. The objective of our work is to study the effects of fatty acids on lipid peroxidation mediated cell death in human adipocytes.
Methods: We treated differentiated human adipocytes with different fatty acids (oleic, palmitic, linoleic, alpha-linolenic, arachidonic, eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids, 7.8-250 µM) conjugated with bovine serum albumin in 2:1 ratio. After 1-7 days of treatment, we measured cell viability (MTT assay), lipid peroxidation (staining with BODIPYTM 581/591 C11 followed by fluorescence microscopy), and expression levels of antioxidant and ferroptosis markers (qPCR and western blot).
Results: We found that very long-chain polyunsaturated fatty acids (PUFAs) dose and time dependently induced cell death in human adipocytes. Further, this cytotoxic effect was proportional to the number of double bonds and carbon chain length of fatty acids. BODIPYTM 581/591 C11 staining showed that very long-chain PUFAs increased lipid peroxidation. Co-treatment with ferrostatin-1 (a potent inhibitor of ferroptosis, 5 µM) blocked very long-chain PUFA-mediated cell death and lipid peroxidation. Docosahexaenoic acid (DHA) significantly decreased mRNA expression levels of glutathione peroxidase 4 while increasing heme oxygenase 1. Similarly, DHA treatment decreased protein expression of nuclear factor erythroid 2 related factor 2 and ferroptosis suppressor protein-1 while increasing solute carrier family 7 member 11. Co-treatment with ferrostatin-1 blocked the effects of DHA on expression levels of antioxidant and ferroptosis markers.
Conclusions: Overall, this study reveals that high concentration of very long-chain PUFAs induced ferroptosis in human adipocytes. Very long-chain PUFAs may mitigate obesity by inducing ferroptosis in adipocytes.
Funding Sources: This work was supported by grants from NIH and USDA.
