Reproductive tradeoffs govern sexually dimorphic tubular lysosome induction in Caenorhabditis elegans

Increased expression of the small lysosomal gene SVIP in the Drosophila gut suppresses pathophysiological features associated with a high-fat diet

Lysosomes are digestive organelles that are crucial for nutrient sensing and metabolism. Lysosome impairment is linked to a broad spectrum of metabolic disorders, underscoring their importance to human health. Thus, lysosomes are an attractive target for metabolic disease therapies. In previous work, we discovered a novel class of tubular lysosomes that are morphologically and functionally distinct from traditionally described vesicular lysosomes. Tubular lysosomes are present in multiple tissues, are broadly conserved from invertebrates to mammals, are more proficient at degrading autophagic cargo than vesicular lysosomes, and delay signs of tissue aging when induced ectopically. Thus, triggering tubular lysosome formation presents one mechanism to increase lysosome activity and, notably, overproduction of the small lysosomal protein, SVIP, is a robust genetic strategy for triggering lysosomal tubulation on demand. In this study, we examine whether SVIP overexpression in the fly gut can suppress pathophysiological phenotypes associated with an obesogenic high-fat diet. Indeed, our results indicate that increasing SVIP expression in the fly gut reduces lipid accumulation, suppresses body mass increase, and improves survival in flies fed a high-fat diet. Collectively, these data hint that increasing lysosomal activity through induction of tubular lysosomal networks, could be one strategy to combat obesity-related pathologies.

Human SVIP is sufficient to stimulate tubular lysosomes and extend healthspan in well-fed Caenorhabditis elegans

Small VCP Interacting Protein (SVIP) is essential for maintaining a unique form of tubular lysosomes (TLs) in Drosophila . Although Caenorhabditis elegans do not have an annotated SVIP ortholog, expression of Drosophila SVIP in the C. elegans intestine induces TLs constitutively, increases autophagic activity, and extends healthspan. Here, we find that expression of the human ortholog of SVIP in the C. elegans gut causes similar physiological and phenotypic effects as Drosophila SVIP , albeit some effects were less pronounced. These results demonstrate that human SVIP can induce functional TLs in C. elegans but may be a weaker allele compared to Drosophila SVIP .

Tubular lysosome induction couples animal starvation to healthy aging

Dietary restriction promotes longevity in several species via autophagy activation. However, changes to lysosomes underlying this effect remain unclear. Here using the nematode Caenorhabditis elegans, we show that the induction of autophagic tubular lysosomes (TLs), which occurs upon dietary restriction or mechanistic target of rapamycin inhibition, is a critical event linking reduced food intake to lifespan extension. We find that starvation induces TLs not only in affected individuals but also in well-fed descendants, and the presence of gut TLs in well-fed progeny is predictive of enhanced lifespan. Furthermore, we demonstrate that expression of Drosophila small VCP-interacting protein, a TL activator in flies, artificially induces TLs in well-fed worms and improves C. elegans health in old age. These findings identify TLs as a new class of lysosomes that couples starvation to healthy aging.