Old and "hangry" monocytes turn from friend to foe under assault

Area of Science:

• Immunology
• Metabolic regulation
• Host-pathogen interactions

Background:

• Monocyte behavior and function are influenced by nutritional status.
• The precise mechanisms and functional consequences of fasting on monocytes are not fully understood.
• Understanding these dynamics is crucial for comprehending host defense.

Purpose of the Study:

• To investigate the impact of fasting and refeeding on monocyte dynamics.
• To elucidate the functional significance of these monocyte changes in the context of host response to infection.
• To identify the underlying mechanics of monocyte migration during fasting.

Main Methods:

• Utilized mouse models to study monocyte behavior during fasting and refeeding.
• Employed flow cytometry and molecular analyses to assess monocyte phenotype and location.
• Investigated the host's response to infection following periods of fasting and refeeding.

Main Results:

• Demonstrated that fasting and subsequent refeeding induce monocytes to re-enter the bone marrow.
• Observed significant alterations in monocyte phenotype and distribution.
• Showcased a modified host response to infection correlated with these monocyte changes.

Conclusions:

• Fasting and refeeding orchestrate a significant shift in monocyte trafficking and function.
• Monocyte re-entry into the bone marrow during fasting impacts the immune system's ability to combat infection.
• These findings provide novel mechanistic insights into the interplay between metabolism and immunity.