Elevated pentose phosphate pathway flux supports appendage regeneration

Area of Science:

• Cell Biology
• Metabolic Biochemistry
• Developmental Biology

Background:

• Regeneration requires rapid cell proliferation and biosynthesis.
• Metabolic reprogramming is crucial for supporting the high energy and precursor demands of regenerating tissues.
• Understanding these metabolic pathways is key to unlocking regenerative potential.

Purpose of the Study:

• To elucidate the metabolic pathways supporting appendage regeneration in Xenopus tropicalis.
• To investigate the role of glucose metabolism, specifically glycolysis and the pentose phosphate pathway (PPP), in regenerative growth.
• To identify key metabolic drivers of cell division during regeneration.

Main Methods:

• Multimodal investigation including Xenopus tropicalis appendage regeneration models.
• Metabolic flux analysis using glucose uptake measurements.
• Liquid chromatography-mass spectrometry (LC-MS) for metabolite profiling.
• Single-cell RNA sequencing (scRNA-seq) to analyze gene expression in proliferating cells.

Main Results:

• Regenerating tissues exhibit increased glucose uptake, but glycolysis inhibition does not impede regeneration.
• Glucose is preferentially channeled into the pentose phosphate pathway (PPP), which is critical for tail regeneration.
• Metabolite profiling revealed elevated nucleotide and nicotinamide intermediates necessary for cell division.
• scRNA-seq showed increased PPP enzyme transcription in highly proliferative cells, unlike glycolytic enzymes.
• Inhibition of the PPP significantly reduced cell division in regenerating tissues.

Conclusions:

• Regenerating tissues in Xenopus tropicalis prioritize the pentose phosphate pathway (PPP) over glycolysis for growth.
• The PPP provides essential nucleotide precursors that fuel the rapid cell proliferation required for appendage regeneration.
• This metabolic strategy ensures sufficient building blocks for DNA and RNA synthesis during tissue repair.