The iFat1 transgene permits conditional endogenous n-3 PUFA enrichment both in vitro and in vivo

Shannon E Clarke,David W L Ma,Jing X Kang

doi:10.1007/s11248-014-9788-x

Shannon E Clarke, David W L Ma + Show 1 more

Open Access

https://doi.org/10.1007/s11248-014-9788-x

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Abstract

Fat-1 transgenic mice, which endogenously convert n-6 PUFA to n-3 PUFA, are a useful tool in health research; however with this model timing of n-3 PUFA enrichment cannot be directly controlled. To add such capability, the novel Cre-recombinase inducible fat-1 (iFat1) transgenic mouse has been developed. The aim of this study was to characterize the utility of the iFat1 transgene as a model of Cre-inducible endogenous n-3 PUFA enrichment. Functionality of the iFat1 transgene was screened both in vitro and in vivo. In the presence of Cre, the iFat1 transgene resulted in a balancing (p < 0.01) of the n-6/n-3 PUFA ratio within phospholipids in the human embryonic kidney 293T cell line. For in vivo analysis, iFat1 transgenic mice were crossed with the R26-Cre-ERT2 (Tam-Cre) mouse line, a tamoxifen inducible Cre-expression model. Tam-Cre/iFat1 double hybrids were transiently treated with tamoxifen at 6–7 weeks, then terminated 3 weeks later. Tamoxifen treated mice had increased (p < 0.05) tissue n-3 PUFA and ≥two-fold reduction (p < 0.05) in the n-6/n-3 PUFA ratio of liver, kidney and muscle phospholipids relative to vehicle treated controls. Collectively these findings suggest that the iFat1 transgenic mouse may be a promising tool to help elucidate the temporal effects through which n-3 PUFA impacts health related outcomes.

Highlights

In recent years, dietary n-3 PUFA, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have garnered strong research and public interest due to their numerous reported beneficial health effects (Anderson and Ma 2009; Fetterman and Zdanowicz 2009)
It was observed that background Cre-independent mRNA expression from the inducible fat-1 (iFat1) transgene was detected by RT-PCR (Fig. 4), this did not correspond to changes in fatty acid composition
Total n-6 PUFA content (PE, PC) and total n-3 PUFA content (PE, PC) did not significantly differ between cells co-transfected with iFat1/Empty and control cells which had been treated with transfecting reagent alone (No DNA)

Summary

Introduction

Dietary n-3 PUFA, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have garnered strong research and public interest due to their numerous reported beneficial health effects (Anderson and Ma 2009; Fetterman and Zdanowicz 2009). Mammals lack this gene and are unable to synthesize n-3 PUFA and must be obtained through the diet To date, this transgenic mouse model has greatly enhanced our insight into the protective effects of lifelong endogenous tissue n-3 PUFA enrichment on numerous health related outcomes including, cancer chemoprevention, bone development, inflammatory/immune pathology, and neurological disease (Kang 2007; Lau et al 2009a, b; Lebbadi et al 2011; MacLennan et al 2013). The ability to more clearly define critical periods of development during which n-3 PUFA can elicit health related benefits will greatly assist in refining the therapeutic applicability of this class of fatty acids

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