Elevated pentose phosphate pathway flux supports appendage regeneration

A fundamental step in regeneration is rapid growth to replace lost tissue. Cells must generate sufficient lipids, nucleotides, and proteins to fuel rapid cell division. To define metabolic pathways underlying regenerative growth, we undertake a multimodal investigation of metabolic reprogramming in Xenopus tropicalis appendage regeneration. Regenerating tissues have increased glucose uptake; however, inhibition of glycolysis does not decrease regeneration. Instead, glucose is funneled to the pentose phosphate pathway (PPP), which is essential for full tail regeneration. Liquid chromatography-mass spectrometry (LC-MS) metabolite profiling reveals increased nucleotide and nicotinamide intermediates required for cell division. Using single-cell RNA sequencing (scRNA-seq), we find that highly proliferative cells have increased transcription of PPP enzymes and not glycolytic enzymes. Further, PPP inhibition results in decreased cell division specifically in regenerating tissue. Our results inform a model wherein regenerating tissues direct glucose toward the PPP, yielding nucleotide precursors to drive regenerative cell proliferation. [Display omitted] •Regenerating tail tissue in Xenopus tropicalis increases glucose uptake•Glucose is metabolized through the pentose phosphate pathway in tail regeneration•Regenerating tails have increased proliferative metabolite pools•Proliferation in regenerating tissues is enabled by PPP activity Regenerating tissues have a large demand for biosynthetic intermediates to drive growth. Patel et al. investigate how this need is met in Xenopus tropicalis tail regeneration by examining glucose metabolism through the pentose phosphate pathway, which is required to sustain proliferation in regenerating tissues.