Altered signalling from germline to intestine pushes daf-2;pept-1 Caenorhabditis elegans into extreme longevity

Aging Cell. 2010 Aug;9(4):636-46. doi: 10.1111/j.1474-9726.2010.00591.x. Epub 2010 Jun 9.

Abstract

The insulin-like signalling pathway is a central regulator of development, metabolism, stress resistance and lifespan in eukaryotes. Caenorhabditis elegans daf-2(e1370) animals with a loss-of-function mutation in the insulin-like receptor live twice as long as wild-type animals, and the additional knockout of the intestinal di- and tripeptide transporter pept-1 further increases lifespan by 60%. In assessing the underlying molecular mechanisms for this phenomenon, microarray-based transcriptome data sets of daf-2(e1370) and daf-2(e1370);pept-1(lg601) animals were compared with a focus on genes that showed significantly higher changes in expression levels in daf-2;pept-1 than in daf-2. We identified 187 genes with at least fourfold decreased transcript levels and 170 with more than a fourfold increase. A large fraction of the down-regulated genes encode proteins involved in germline proliferation and reproduction. The DAF-9/DAF-12 signalling cascade was identified as a prime pathway that mediates the longevity of daf-2;pept-1 with a strict dependance on DAF-16. Loss of DAF-9/DAF-12 or KRI-1 reduces the lifespan of daf-2;pept-1 to that of the daf-2 mutant. Amongst the DAF-16 target genes, numerous enzymes involved in the defence of reactive oxygen species were with increased expression level in daf-2;pept-1. On a functional level, it was demonstrated that amongst those, a high de novo synthesis rate of glutathione is most important for the longevity phenotype of this strain. Taken together, a close interdependence of endocrine hormone signalling from germline to intestine was identified as an essential element in the control of the extreme longevity of C. elegans lacking a proper function of the insulin receptor and lacking the intestinal peptide transporter.

MeSH terms

  • Animals
  • Caenorhabditis elegans / cytology
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / immunology
  • Caenorhabditis elegans / physiology*
  • Caenorhabditis elegans Proteins / metabolism*
  • Cell Proliferation
  • Down-Regulation / genetics
  • Genes, Helminth / genetics
  • Germ Cells / metabolism*
  • Glutathione / metabolism
  • Homeostasis
  • Intestinal Mucosa / metabolism*
  • Longevity / physiology*
  • Models, Biological
  • Mutation / genetics
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Reactive Oxygen Species / metabolism
  • Receptor, Insulin / metabolism*
  • Reproduction / genetics
  • Signal Transduction*

Substances

  • Caenorhabditis elegans Proteins
  • RNA, Messenger
  • Reactive Oxygen Species
  • DAF-2 protein, C elegans
  • Receptor, Insulin
  • Glutathione