Directional migration of leukocytes: their pathological roles in inflammation and strategies for development of anti-inflammatory therapies.

Directional migration of leukocytes is indispensable to innate immunity for host defense. However, recruitment of leukocytes to a site of tissue injury also constitutes a leading cause for inflammatory responses. Mechanistically, it involves a cascade of cellular events precisely regulated by temporal and spatial presentation of a repertoire of molecules in the migrating leukocytes and their surroundings (microenvironments). Here I will summarize the emerging evidence that has shed lights on the underlying molecular mechanism for directional migration of leukocytes, which has guided the therapeutical development for innovative anti-inflammatory medicines.