The cytotoxicity of 27-hydroxycholesterol in co-cultured SH-SY5Y cells and C6 cells

Background: Diverse physiological and pathological functions of 27-hydroxycholesterol (27-OHC) were proved. However, cytotoxicity and potential influence of 27-OHC on cholesterol metabolism in neurons are unclear. Design and methods: In the vitro co-culture system, SH-SY5Y cells and C6 cells were applied to explore the potential cytotoxicity of 27-OHC. MIT assay was used to detect the cell proliferation. Cell vitality was measured by using the Annexin-FITC/PI test. Immunofluorescence technique was applied to observe the changes of mitochondria membrane potential. The expression of mRNA and protein (including SREBP-1, HMGCR, LXR-alpha, ABCA1) were measured by real-time PCR and western blot method respectively. Results: 27-OHC induced apoptosis in co-cultured SH-SY5Y cells and C6 cells. 27-OHC treatment significantly inhibited cell viability and proliferation (p < 0.05). Compared with control group, 27-OHC caused the reduction of mitochondrial membrane potential (p < 0.05). Additionally, the mRNA and protein expression of cholesterol synthesis-related factors, such as SREBP-1, HMGCR, were down-regulated (p < 0.05), while the mRNA and protein expression of cholesterol transport-related factors (LXR-alpha, ABCA1) were up-regulated (p < 0.05). Conclusions: Cytotoxicity and cholesterol metabolism disorder induced by 27-OHC may contribute to the pathogenesis of neurodegenerative disease. (C) 2016 Elsevier Ireland Ltd. All rights reserved.