Heightened cholesterol 25-hydroxylase expression in aged lung during Streptococcus pneumoniae
David G Thomas1,2, Jianjun Yang1, Soo Jung Cho1,2
1Department of Medicine, Pulmonary and Critical Care, Weill Cornell Medicine, New York, NY, United States.
Frontiers in Aging
|December 24, 2024
Summary
Cholesterol 25-hydroxylase (Ch25h) impacts aged alveolar macrophages during Streptococcus pneumoniae infection. Reducing Ch25h improves bacterial clearance and immune responses in aging lungs.
Area of Science:
- Immunology
- Cell Biology
- Aging Research
Background:
- Alveolar macrophages (AM) are crucial for lung immunity against Streptococcus pneumoniae.
- Altered lipid metabolism in AM can lead to inflammation and impaired function.
- Aging affects immune cell function, increasing susceptibility to infections.
Purpose of the Study:
- To investigate the role of cholesterol 25-hydroxylase (Ch25h) in aged AM during S. pneumoniae infection.
- To determine if modulating Ch25h affects AM responses and bacterial clearance in aging lungs.
Main Methods:
- Utilized in vitro and in vivo murine models of S. pneumoniae infection.
- Employed Ch25h-specific siRNA to reduce enzyme expression in aged macrophages and lungs.
- Assessed AM cholesterol metabolism, lipid droplet formation, phagocytic receptor expression, and bacterial clearance.
Main Results:
- Aging altered cholesterol metabolism and increased lipid droplets in AM.
- Ch25h inhibition in vitro enhanced S. pneumoniae clearance and phagocytic receptor expression.
- In vivo Ch25h reduction improved clinical outcomes and bacterial clearance in aged mice.
Conclusions:
- Cholesterol 25-hydroxylase (Ch25h) is a key regulator of aged AM function during S. pneumoniae infection.
- Targeting Ch25h represents a potential therapeutic strategy to enhance immune responses in aging lungs.
