Uncovering lipid dynamics in Staphylococcus aureus osteomyelitis using multimodal imaging mass spectrometry

Area of Science:

• Biochemistry
• Microbiology
• Pathology

Background:

• Osteomyelitis is a bone infection caused by Staphylococcus aureus.
• The infection creates a bone marrow abscess with a complex cellular and molecular structure.
• Understanding the lipid changes during infection is crucial for developing new treatments.

Purpose of the Study:

• To spatially map the lipidome in Staphylococcus aureus-infected murine femurs.
• To identify alterations in lipid composition associated with infection and abscess formation.
• To investigate the role of lipids in cellular signaling and metabolism during osteomyelitis.

Main Methods:

• Imaging mass spectrometry and microscopy were used to analyze lipid distribution.
• Nearly 250 lipids were spatially mapped in healthy and infected murine femurs.
• Lipid profiles were correlated with morphological features of the bone marrow abscess.

Main Results:

• Significant alterations in ether lipids and arachidonoyl lipids were observed in abscesses.
• Sterols, triglycerides, bis(monoacylglycero)phosphates, and gangliosides showed ring-like distributions.
• These lipid changes suggest dysregulated lipid metabolism in specific cell populations within the abscess.

Conclusions:

• The study reveals specific lipid alterations associated with Staphylococcus aureus osteomyelitis.
• Altered lipid profiles provide insights into abscess formation, inflammatory signaling, and cellular metabolism.
• Findings suggest lipid-laden macrophages play a role in the fibrotic border of abscesses.