The regulation of inflammation by galectin-3

Galectin-3 is a beta-galactoside-binding animal lectin of appro- ximately 30 kDa and is evolutionarily highly conserved. Galectin-3 is promiscuous, its localization within the tissue micro-environment may be extracellular, cytoplasmic, or nuclear, and it has a concentration-dependent ability to be monomeric or form oligomers. These properties impart great flexibility on galectin-3 as a specific regulator of many biological systems including inflammation. For example, in acute tissue damage galectin-3 is a key component in the host defense against microbes such as Streptococcus pneumoniae. However, if tissue injury becomes repetitive galectin-3 also appears to be intimately involved in the transition to chronic inflammation, facilitating the walling off of tissue injury with fibrogenesis and organ scarring. Therefore galectin-3 can be viewed as a regulatory molecule acting at various stages along the continuum from acute inflammation to chronic inflammation and tissue fibrogenesis. In this review, we examine the role of galectin-3 in inflammation, and discuss the manipulation of galectin-3 expression as a potentially novel therapeutic strategy in the treatment of a broad range of inflammatory diseases.