Enhanced insulin sensitivity associated with provision of mono and polyunsaturated fatty acids in skeletal muscle cells involves counter modulation of PP2A.
Level 5 - mechanism / opinion, no new human data
In vitro cell culture study without human in vivo data (mechanism-based bench research)
PubMed 24632852 · doi:10.1371/journal.pone.0092255
What was done
Cultured rat and human skeletal myotubes were treated with saturated fatty acid (palmitate; PA), monounsaturated fatty acid (oleic acid; OA), or polyunsaturated fatty acid (linoleic acid; LOA). The authors evaluated downstream insulin signaling (Akt and ERK1/2), upstream signaling components (IRS1 and PI3K), and the phosphorylation (tyrosine-307) and methylation status of the catalytic subunit of protein phosphatase 2A (PP2Ac).
What was found
The abstract reports no numerical values. Sustained incubation with OA or LOA significantly enhanced Akt- and ERK1/2-directed insulin signaling compared to PA. Upstream IRS1 and PI3K signaling and proximal protein expression were unchanged, but dephosphorylation of Akt and ERK1/2 was reduced. PA reduced PP2Ac demethylation and tyrosine-307 phosphorylation (activating PP2A), whereas OA and LOA opposed these PA-induced modifications, repressing PP2A activity.
Why it matters
It identifies protein phosphatase 2A (PP2A) modulation as a molecular mechanism by which unsaturated fatty acids counter saturated fatty acid-induced insulin resistance in skeletal muscle cells.
Limits
The study is restricted to in vitro cultured rat and human myotubes without in vivo testing. The abstract provides no quantitative data, sample sizes, fatty acid concentrations, or exposure durations, and clinical metabolic outcomes were not measured.
Cited by
- supports Co-incubating cells with oleic acid or linoleic acid reverses palmitate-induced insulin resistance.