Neutrophils-From Bone Marrow to First-Line Defense of the Innate Immune System

Area of Science:

• Immunology
• Cell Biology

Background:

• Neutrophils (polymorphonuclear cells; PMNs) are crucial for innate immunity against pathogens.
• Dysregulated PMN activation contributes to tissue damage in various diseases, including infectious, autoimmune, trauma, and shock conditions.
• Recent research redefines neutrophils' role beyond pathogen defense to maintaining general body integrity.

Purpose of the Study:

• To review the multifaceted role of neutrophils (PMNs) within the innate immune system.
• To elucidate PMN migration, chemotaxis, and immune functions at inflammatory sites.
• To explore novel aspects of PMN behavior in cancer and tumor microenvironments.

Main Methods:

• Literature review focusing on neutrophil migration, extracellular matrix interactions, and chemotactic gradient formation.
• Analysis of bidirectional and reverse PMN migration mechanisms.
• Synthesis of current knowledge on neutrophil microtubules and their organizing centers.
• Review of recent findings on neutrophils in cancer contexts.

Main Results:

• PMNs migrate from vasculature to tissues, guided by chemotactic gradients influenced by the extracellular matrix (ECM).
• The ECM significantly impacts PMN function and migration dynamics.
• Bidirectional/reverse migration and the role of neutrophil microtubules are critical for PMN homing.
• Neutrophils exhibit complex behaviors within the tumor microenvironment.

Conclusions:

• Neutrophils are vital immune cells with complex roles extending to tissue homeostasis and disease pathogenesis.
• Understanding PMN migration and ECM interactions is key to modulating their function.
• Emerging research highlights neutrophils' significant involvement in cancer progression and immunity.