Overexpression of stearoyl-CoA desaturase-1 results in an increase of conjugated linoleic acid (CLA) and n-7 fatty acids in 293 cells

The effect of human SCD1 heterologous expression on cellular fatty acid synthesis was investigated in the current study. The SCD1 gene expression cassette and PGK-neomycin-selectable marker cassette were co-introduced into HEK 293 cells by electroporation, and subsequently, SCD1 expression was evaluated by fatty acid analysis. RT-PCR analysis indicated that the foreign SCD1 gene could be expressed in transformed cell lines. Total lipid analysis of the transformed cells fed with vaccenic acid (t11-18:1) as a substrate showed that SCD1 expression resulted in an increase in c9t11-CLA from 0.73–1.03% to 2.69–2.86% (p < 0.05) and that the conversion efficiency was elevated from 5.11–6.88% to 16.49–20.06% (p < 0.05). Surprisingly, the concentration of t10c12-CLA was also increased, from 0.10–0.41% to 1.35–1.69% in SCD1 cells (p < 0.05). SCD1 expression also resulted in a significant (p < 0.05) increase in palmitoleic acid (16:1 n-7) from 1.56–2.26% to 3.47–4.04% and cis-vaccenic acid (18:1 n-7) from 2.42–3.97% to 6.20–7.22%, and the corresponding conversion ratio of n-7 fatty acid was elevated from 12.01–16.70% to 22.62–24.13% (p < 0.05). This study demonstrates that the foreign SCD1 gene was expressed with high efficiency and induced elevated c9t11-CLA, t10c12-CLA, and n-7 fatty acid levels in mammalian cells.

Research highlights
► Heterologous expression of stearoyl-CoA desaturase elevates the c9t11-CLA amounts.
► Overexpression of SCD1 also results in an increase of t10c12-CLA in cells.
► Overexpression of SCD1 elevates the amount of n-7 fatty acids in cells.
► Overexpression of SCD1 has not elevated the amount of n-9 fatty acids.