[Nitric oxide and macrophages]

Area of Science:

• Biochemistry
• Immunology
• Cell Biology

Context:

• Nitric oxide (NO) is a critical signaling molecule produced from L-arginine by nitric oxide synthase (NOS).
• NO plays a vital role in host defense against a wide range of pathogens, including fungi, bacteria, protozoa, helminths, and viruses.
• While NOS II is well-characterized in murine macrophages, its presence and function in human monocytes/macrophages have been debated.

Purpose:

• To review recent findings and developments regarding the L-arginine-NO pathway in human monocytes/macrophages.
• To address the long-standing questions surrounding the existence and significance of NO production in these human immune cells.

Summary:

• Nitric oxide (NO), derived from L-arginine, is produced by virtually all cells and functions in pathogen defense.
• High-output nitric oxide synthase (NOS II) is regulated by cytokines and microbial products in murine macrophages.
• This review focuses on recent evidence clarifying the presence and role of the L-arginine-NO pathway in human monocytes and macrophages.

Impact:

• Clarifies the role of nitric oxide in human innate immunity.
• Provides insights into the regulation and function of NOS II in human monocytes/macrophages.
• Highlights the importance of the L-arginine-NO pathway for host defense mechanisms in humans.