Microbiome contribution to Indy longevity in Drosophila

Area of Science:

• Aging and Longevity Research
• Microbiology and Gut Health
• Molecular Biology and Genetics

Background:

• The Indy (I'm not dead yet) gene, a citrate transporter, is crucial for metabolic homeostasis and its reduction extends lifespan.
• Aging is associated with gut dysbiosis, impaired intestinal barrier function, and increased mortality.
• The mechanisms linking increased microbial load to frailty and negative health outcomes in aging are not fully understood.

Purpose of the Study:

• To investigate the role of Indy gene reduction in modulating gut microbiota composition and its impact on aging and longevity.
• To explore the underlying molecular mechanisms, including JAK/STAT signaling, by which Indy reduction affects intestinal homeostasis.
• To determine the interaction between Indy gene activity and the gut microbiome in promoting healthspan and lifespan.

Main Methods:

• Comparative analysis of gut bacterial load and microbiome diversity in Indy heterozygote flies versus control flies during aging.
• Assessment of intestinal barrier integrity and stem cell homeostasis in Indy-reduced flies.
• Evaluation of JAK/STAT signaling pathway components (Upd3, Upd2) in the midgut of young Indy flies.
• Experiments involving germ-free conditions to assess the necessity of the microbiome for Indy-mediated lifespan extension.

Main Results:

• Indy heterozygote flies exhibited significantly lower bacterial load and increased microbiome diversity during aging compared to controls.
• Microbiome presence was not essential for Indy-mediated lifespan extension; its removal further enhanced longevity.
• Down-regulation of Indy was associated with reduced expression of JAK/STAT signaling ligands (Upd3, Upd2) in the midgut, preserving intestinal stem cell homeostasis.
• Indy reduction delayed age-associated pathology in the fly midgut, maintaining intestinal barrier integrity.

Conclusions:

• Indy gene reduction impacts gut microbiome load and composition, contributing to preserved gut homeostasis and extended lifespan.
• The observed effects are partly mediated through modulation of the JAK/STAT signaling pathway in the gut.
• Interactions between the Indy gene and the gut microbiome play a significant role in regulating aging and longevity.