Alveolar macrophage transcriptomic profiling in COPD shows major lipid metabolism changes

Area of Science:

• Pulmonary Medicine
• Immunology
• Metabolomics

Background:

• Immune cells, particularly alveolar macrophages (AMs), are crucial in chronic obstructive pulmonary disease (COPD) pathogenesis.
• While changes in immune cell distribution and function are known, their transcriptional reprogramming and role in COPD pathophysiology require further investigation.

Purpose of the Study:

• To investigate transcriptional reprogramming and lipid metabolism alterations in AMs from COPD patients.
• To understand the contribution of these changes to COPD pathophysiology.

Main Methods:

• Whole transcriptome and lipidome analyses were performed on sorted AMs from control and COPD subjects.
• Specific cell populations (CD45+Lin-HLA-DR+CD66b-Autofluorescencehi AMs) were isolated from bronchoalveolar lavage fluid.

Main Results:

• Global transcriptional reprogramming was observed in COPD AMs, indicating diverse activation states including pro- and anti-inflammatory signatures.
• Significant alterations in genes related to lipid metabolism, such as fatty acid biosynthesis, were identified, particularly in GOLD2 stage COPD patients.
• Analysis of 202 lipid species revealed disease grade-dependent changes in cholesteryl esters, monoacylglycerols, and phospholipids within AMs.

Conclusions:

• Transcriptome and lipidome profiling of COPD AMs demonstrates GOLD grade-dependent alterations.
• Key changes were noted in cholesterol metabolism and interferon-α and γ responses, offering insights into COPD mechanisms.