A vitamin-B2-sensing mechanism that regulates gut protease activity to impact animal’s food behavior and growth

Abstract

To survive challenging environments, animals acquired the ability to evaluate food quality in the intestine and respond to nutrient deficiencies with changes in food-response behavior, metabolism and development. However, the regulatory mechanisms underlying intestinal sensing of specific nutrients, especially micronutrients such as vitamins, and the connections to downstream physiological responses in animals remain underexplored. We have established a system to analyze the intestinal response to vitamin B2 (VB2) deficiency in Caenorhabditis elegans, and demonstrated that VB2 level critically impacts food uptake and foraging behavior by regulating specific protease gene expression and intestinal protease activity. We show that this impact is mediated by TORC1 signaling through reading the FAD-dependent ATP level. Thus, our study in live animals uncovers a VB2-sensing/response pathway that regulates food-uptake, a mechanism by which a common signaling pathway translates a specific nutrient signal into physiological activities, and the importance of gut microbiota in supplying micronutrients to animals.DOI: http://dx.doi.org/10.7554/eLife.26243.001

Microbial Siderophore Enterobactin Promotes Mitochondrial Iron Uptake and Development of the Host via Interaction with ATP Synthase

“…A Bacterial Mutant Screen Identifies the Benefit of E. Coli-Produced Ent to Host Development We created a unique assay to facilitate the identification of microbial metabolites that benefit growth and development of host animals. Our previous studies revealed that heat-killed (HK) E. coli lacks certain molecules that are collectively required for C. elegans larval growth (Qi et al, 2017). Larval growth was recovered when the heat-killed E. coli plate was supplemented with a trace amount of live E. coli, which alone could not support worm growth ( Figure 1A), suggesting that the trace amount of live bacteria generated metabolites that rendered the heat-killed food usable.…”

“…Recent studies have demonstrated that the nematode C. elegans is an excellent system to study functions of bacterial metabolites on animal physiology (e.g., Garcia-Gonzalez et al, 2017;Gusarov et al, 2013;Han et al, 2017;Meisel et al, 2014;Samuel et al, 2016;Scott et al, 2017). We have previously developed a unique assay system to evaluate the impact of microbiota-produced metabolites on animal development and behaviors, which led to the identification of an intestinal pathway that regulates animal food behaviors in response to deficiency of bacteria-produced vitamin B2 (Qi et al, 2017).…”

Nutrient Sensing and Response Drive Developmental Progression in Caenorhabditis elegans

“…Vitamin B2 (Riboflavin) is required for animals to progress through L1. B2 promotes intestinal protease expression and activity that likely promotes digestion . In this context, B2 may be required for the absorption of many nutrients, and its absence may induce a starvation state.…”

Bacterial Siderophores Promote Animal Host Iron Acquisition and Growth

“…The authors take advantage of the ability of C. elegans to grow and develop normally on agar plates seeded with live, but not heat-killed, Escherichia coli. Previously, the authors used this experimental system to define a requirement of C. elegans for vitamin B2, riboflavin (Qi et al, 2017). And Watson et al (2014) had conducted a systemslevel metabolic investigation of the differential growth rates of C. elegans on different bacterial species to identify a benefit of vitamin B12 on growth and development of C. elegans.…”