Research Paper Volume 3, Issue 2 pp 125—147

Modulation of lipid biosynthesis contributes to stress resistance and longevity of C. elegans mutants

Robert J. Shmookler Reis 1, 2, 3, , Lulu Xu 2, , Hoonyong Lee 2, , Minho Chae 2, *, , John J. Thaden 2, , Puneet Bharill 1, 3, , Cagdas Tazearslan 3, , , Eric Siegel 4, , Ramani Alla 1, , Piotr Zimniak 1, 5, , Srinivas Ayyadevara 1, 2, ,

  • 1 Central Arkansas Veterans Healthcare Service, Little Rock, AR 72205, USA
  • 2 Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
  • 3 Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
  • 4 Department of Biostatistics University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
  • 5 Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
* National Center for Toxicologic Research, Jefferson, AR, USA
† Dept. of Genetics, Albert Einstein College of Medicine, Bronx NY 10461 USA

received: February 3, 2011 ; accepted: February 24, 2011 ; published: February 25, 2011 ;

https://doi.org/10.18632/aging.100275
How to Cite

Abstract

Many lifespan-modulating genes are involved in either generation of oxidative substrates and end-products, or their detoxification and removal. Among such metabolites, only lipoperoxides have the ability to produce free-radical chain reactions. For this study, fatty-acid profiles were compared across a panel of C. elegans mutants that span a tenfold range of longevities in a uniform genetic background. Two lipid structural properties correlated extremely well with lifespan in these worms: fatty-acid chain length and susceptibility to oxidation both decreased sharply in the longest-lived mutants (affecting the insulinlike-signaling pathway). This suggested a functional model in which longevity benefits from a reduction in lipid peroxidation substrates, offset by a coordinate decline in fatty-acid chain length to maintain membrane fluidity. This model was tested by disrupting the underlying steps in lipid biosynthesis, using RNAi knockdown to deplete transcripts of genes involved in fatty-acid metabolism. These interventions produced effects on longevity that were fully consistent with the functions and abundances of their products. Most knockdowns also produced concordant effects on survival of hydrogen peroxide stress, which can trigger lipoperoxide chain reactions.

Abbreviations

ACL: average chain length; DBI: double bond index; FA: fatty acid; FAME: fatty acid methyl ester; GC-MS: gas chromatography - mass spectrometry; IIS: insulin/insulinlike growth factor-1 signaling; mmBC: monomethyl branched-chain; MUFA: monounsaturated fatty acid; PI: peroxidation index; PUFA: polyunsaturated fatty acid; RT-PCR: real-time reverse transcriptase PCR.