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Egan, B. M.

Publications and source records attributed to Egan, B. M..

2 recordsLinked to original sources

The ACE-inhibitor drug captopril inhibits ACN-1 to control dauer formation and aging

The renin-angiotensin-aldosterone system (RAAS) plays a well-characterized role regulating blood pressure in mammals. Pharmacological and genetic manipulation of the RAAS has been shown to extend lifespan in C. elegans, Drosophila, and rodents, but its mechanism is not well defined. Here we investigate the angiotensin-converting enzyme (ACE) inhibitor drug captopril, which extends lifespan in worms and mice. To investigate the mechanism, we performed a forward genetic screen for captopril hypersensitive mutants. We identified a missense mutation that causes a partial loss-of-function of the daf-2 receptor tyrosine kinase gene, a powerful regulator of aging. The homologous mutation in the human insulin receptor causes Donohue syndrome, establishing these mutant worms as an invertebrate model of this disease. Captopril functions in C. elegans by inhibiting ACN-1, the worm homolog of ACE. Reducing the activity of acn-1 via captopril or RNAi promoted dauer larvae formation, suggesting acn-1 is a daf gene. Captopril-mediated lifespan extension xwas abrogated by daf-16(lf) and daf-12(lf) mutations. Our results indicate that captopril and acn-1 control aging by modulating dauer formation pathways. We speculate that this represents a conserved mechanism of lifespan control. Summary StatementCaptopril and acn-1 control aging. By demonstrating they regulate dauer formation and interact with daf genes, including a new DAF-2(A261V) mutant corresponding to a human disease variant, we clarified the mechanism.

developmental biology↗

Notch signaling in germ line stem cells controls reproductive aging in C. elegans

Reproductive aging in females often occurs early in life, resulting in a substantial post-reproductive lifespan. Despite the medical importance of age-related infertility, relatively little is known about mechanisms that control this age-related decline. C. elegans is a leading system for aging biology due to its short lifespan and powerful experimental tools, and detailed descriptions of molecular and cellular changes in the gonad during reproductive aging were recently reported. Here we show that reproductive aging occurs early in life in multiple species in the genus Caenorhabditis, indicating this is a feature of both female/male and hermaphrodite/male species. In mutants previously established to display delayed reproductive aging (daf-2, eat-2, phm-2), we observed correlations between changes in the distal germline and changes in egg-laying, consistent with the model that distal germline changes are a cause of reproductive aging. By screening for additional mutants that delay reproductive aging, we identified an allele of che-3 with impaired sensory perception that displayed increased progeny production in mid-life, a pattern of reproductive aging distinct from previous mutants. To directly test the role of Notch signaling in the distal germline, we analyzed the effect of ectopic expression of the Notch effector gene SYGL-1. Ectopic expression of SYGL-1 was sufficient to delay reproductive aging, suggesting that an age-related decline in Notch signaling in the distal germline is a root cause of reproductive aging.

genetics↗