Delta-6 desaturase from borage converts linoleic acid to gamma-linolenic acid in HEK293 cells

Gamma-linolenic acid (GLA, 18:3 n6) is an essential polyunsaturated fatty acid of the omega-6 family and is found to be effective in prevention and/or treatment of various health problems. In this study, we evaluated the possibility of increasing γ-linolenic acid contents in mammalian cells using the delta-6 gene from Borago officinalis. The borage Δ6-desaturase gene (sDelta-6) was codon-optimized and introduced into HEK293 cells by lipofectin transfection. Co-expression of GFP with sDelta-6 and RT-PCR analysis indicated that sDelta-6 could be expressed in mammalian cells. Subsequently, the heterologous expression of borage Δ6-desaturase was evaluated by fatty acid analysis. Total cellular lipid analysis of transformed cells fed with linoleic acid (LA 18:2 n6) as a substrate showed that the expression of sDelta-6 resulted in an 228–483% (p < 0.05) increase of GLA when compared with that in the control cells. The highest conversion efficiency of LA into GLA in sDelta-6+ cells was 6.9 times higher than that in the control group (11.59% vs. 1.69%; p < 0.05). Our present work demonstrated that the sDelta-6 gene from borage could be functionally expressed in mammalian cells, and could convert LA into GLA. Furthermore, this study may pave the way to generate transgenic livestock that can synthesise GLA.

► Delta-6 desaturase (sDelta-6) from borage with optimized codons was synthesised for the better expression in mammalian system.
► sDelta-6 was first cloned into pIRES2-AcGFP1 and expressed in HEK 293 cells.
► Heterologous expression of Δ6-desaturase elevates the GLA amounts in HEK 293 cells.