Immune and metabolic shifts during neonatal development reprogram liver identity and function

Area of Science:

• Immunology
• Metabolism
• Developmental Biology

Background:

• The liver's role shifts from embryonic hematopoiesis to adult immunity and metabolism.
• Postnatal adaptation of the liver's immune system and metabolic functions is not well understood.

Purpose of the Study:

• To investigate the mechanisms of liver adaptation during the postnatal period.
• To understand how the liver's immune and metabolic profiles change after birth.

Main Methods:

• Analysis of mouse and human liver samples from birth to adulthood.
• Phenotyping of liver immune cells using mass cytometry (CyTOF).
• Measurement of immune and metabolic gene expression, and assessment of infection response and metabolic pathway gene expression after early weaning.

Main Results:

• Neonatal livers have distinct cellular composition and immune cell populations (myeloid cells, immature B cells).
• Neonatal mice show increased susceptibility to infection but develop an efficient immune response.
• Metabolic functions mature around weaning; early weaning disrupts metabolic pathway gene expression.

Conclusions:

• Neonatal and adult livers differ significantly in immune and metabolic profiles due to cellular repertoire and phenotype.
• Dietary and antigen exposure are critical for guiding liver development in the postnatal phase.