Induction of uncoupling protein 3 gene expression in skeletal muscle of preterm newborns

Area of Science:

• Biochemistry
• Neonatal Physiology
• Mitochondrial Biology

Background:

• Prematurity is linked to delayed mitochondrial oxidative phosphorylation and impaired metabolic switching.
• Fatty acids (FA) are crucial energy substrates and play a role in activating genes for energy metabolism and lipid oxidation postnatally.
• Understanding mitochondrial activation mechanisms in newborns is vital for addressing metabolic challenges.

Purpose of the Study:

• To investigate the gene expression of mitochondrial uncoupling proteins (UCPs) in preterm neonates.
• To elucidate the role of UCP3 in postnatal lipid oxidation and mitochondrial activation.
• To identify potential mechanisms behind delayed mitochondrial energy conversion in very preterm infants.

Main Methods:

• Analysis of autopsy samples of skeletal and cardiac muscles from preterm neonates and fetuses.
• Quantification of UCP2, UCP3, and FA transport gene transcript levels using real-time reverse transcriptase PCR.
• Correlation of gene expression with gestational age and nutritional status.

Main Results:

• Postnatal induction of UCP3 gene expression in skeletal muscle was observed, consistent with mouse studies.
• Nutritional fatty acids appear to be involved in the induction of UCP3 expression.
• UCP3 plays a role in mitochondrial fatty acid oxidation, with significantly higher levels in skeletal muscle than in cardiac muscle.
• UCP2 gene was expressed in fetuses and unaffected by nutrition.
• Impaired postnatal activation of UCP3 was suggested in neonates born before 26 weeks of gestation.

Conclusions:

• UCP3 is crucial for the postnatal activation of lipid oxidation in skeletal muscle.
• Impaired UCP3 gene activation may contribute to delayed mitochondrial energy conversion in very immature preterm neonates.
• These findings underscore the importance of UCP3 in neonatal metabolic adaptation.