Mitochondrial bioenergetic pathways in blood leukocyte transcriptome decrease after intensive weight loss but are...

Area of Science:

• Human physiology and metabolism
• Molecular biology and transcriptomics
• Nutritional science and endocrinology

Background:

• Weight loss through energy deficit triggers metabolic adaptations to conserve energy, but underlying mechanisms remain unclear.
• Athletic females undergoing dietary changes for physique competition provide a model to study these adaptations.
• Understanding energy conservation mechanisms is crucial for managing weight loss and metabolic health.

Purpose of the Study:

• To investigate the systemic metabolic adaptations in response to prolonged energy deficit and subsequent weight regain.
• To identify molecular mechanisms, including transcriptomic and metabolomic changes, associated with energy conservation.
• To explore the role of specific signaling pathways (AMPK/PGC1-α, mTOR/eIF2) in mediating these adaptations.

Main Methods:

• Analysis of 42 healthy athletic females divided into a dieting group and a control group.
• Collection of fasting blood samples at multiple time points during weight loss and regain phases.
• Utilized RNA-Sequencing for leukocyte transcriptome analysis and Nuclear Magnetic Resonance (NMR) for serum metabolome profiling.

Main Results:

• Significant suppression of mitochondrial oxidative phosphorylation (OXPHOS) and ribosome biogenesis transcriptomic signatures observed during weight loss.
• Upstream regulator analysis indicated involvement of AMPK/PGC1-α and mTOR/eIF2 signaling pathways.
• Metabolic adaptations were detectable systemically through leukocyte transcriptome and serum metabolome analysis.

Conclusions:

• Prolonged energy deprivation induces significant, measurable modulation of mitochondrial metabolism in humans.
• Leukocyte transcriptome and serum metabolome serve as minimally invasive biomarkers for studying systemic metabolic adaptations.
• Human adaptation to energy deficit is more extensive than previously recognized, impacting cellular energy metabolism broadly.