TGFβ-dependent mitochondrial biogenesis is activated during definitive endoderm differentiation

Area of Science:

• Stem cell biology
• Cellular metabolism
• Mitochondrial biology

Background:

• Mitochondrial remodeling and metabolic reprogramming are critical for cell differentiation.
• The specific changes in mitochondria and metabolism during human embryonic stem cell (hESC) differentiation to definitive endoderm (DE) remain largely uncharacterized.

Purpose of the Study:

• To investigate the occurrence and mechanisms of mitochondrial remodeling and metabolic reprogramming during hESC to DE differentiation.
• To determine the role of transforming growth factor-beta (TGF-β) signaling in these processes.

Main Methods:

• Comparative analysis of mitochondrial morphology, mass, and DNA content in undifferentiated hESCs and DE cells.
• Measurement of ATP and reactive oxygen species (ROS) levels.
• Gene expression analysis of metabolic pathways (glycolysis, oxidative phosphorylation) and key regulators like PGC1-A.
• Inhibition of TGF-β signaling to assess its impact on mitochondrial biogenesis and metabolic switch.

Main Results:

• Mitochondria transitioned from fragmented to an extensive network during DE differentiation.
• Significant increases in mitochondrial mass, mtDNA content, ATP production, and ROS levels were observed.
• A metabolic switch from glycolysis to oxidative phosphorylation (OXPHOS) occurred, coupled with upregulated OXPHOS gene expression.
• Inhibition of TGF-β signaling impaired mitochondrial biogenesis and disrupted the metabolic switch.

Conclusions:

• Mitochondrial biogenesis and metabolic reprogramming are integral components of hESC to DE differentiation.
• TGF-β signaling is a key regulator of mitochondrial biogenesis and metabolic adaptation during early endodermal differentiation.