CXC chemokine

CXC Chemokine

CXC chemokines are a family of small cytokines, or signaling proteins secreted by cells, that play a crucial role in the immune system by directing the migration of immune cells to sites of inflammation, infection, and injury. They are characterized by the presence of a CXC motif, where two cysteine residues are separated by one amino acid. This article provides an overview of the structure, function, and clinical significance of CXC chemokines.

Structure

CXC chemokines are part of the larger chemokine family, which is divided into four subfamilies based on the arrangement of the first two cysteine residues: C, CC, CXC, and CX3C. The CXC chemokines are distinguished by having one amino acid between the first two cysteines (C-X-C). This structural motif is critical for their function and receptor binding.

Function

CXC chemokines are primarily involved in the chemotaxis of neutrophils, although some members also attract other types of leukocytes. They bind to specific G protein-coupled receptors on the surface of target cells, triggering intracellular signaling pathways that lead to cell movement.

Angiogenesis

Some CXC chemokines, such as CXCL8 (also known as IL-8), are pro-angiogenic, meaning they promote the formation of new blood vessels. This is particularly important in wound healing and tumor growth.

Inflammation

CXC chemokines are key mediators of inflammation. They are produced in response to inflammatory stimuli and recruit neutrophils and other immune cells to the site of infection or injury. This helps to clear pathogens and initiate tissue repair.

Receptors

CXC chemokines exert their effects by binding to specific receptors on target cells. These receptors are part of the G protein-coupled receptor family and include CXCR1, CXCR2, CXCR3, and others. Each receptor has a distinct pattern of expression and ligand specificity, which determines the biological response.

Clinical Significance

CXC chemokines are involved in a variety of diseases, including:

• Cancer: Many tumors secrete CXC chemokines to promote angiogenesis and recruit immune cells that can aid in tumor growth and metastasis.
• Autoimmune diseases: Dysregulation of CXC chemokine signaling can contribute to the pathogenesis of autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus.
• Infectious diseases: CXC chemokines play a role in the immune response to infections, and their modulation can affect disease outcomes.

Therapeutic Potential

Given their role in disease, CXC chemokines and their receptors are potential targets for therapeutic intervention. Inhibitors of CXC chemokine receptors are being explored as treatments for cancer, inflammatory diseases, and other conditions.

See Also

• Chemokine
• Cytokine
• Immune system

External Links

• National Center for Biotechnology Information
• World Health Organization