CXC Chemokine Family

Chemokines are a family of small, chemoattractant cytokines that play a central role in regulating the migration of cells into inflamed tissue. The CXC-chemokine sub-family is characterized by four cysteine amino acids that form two pairs of disulfide bridges, with the two cysteines proximal to the N-terminus separated by an additional amino acid (CXC). Members of the CXC-chemokine family can be further characterized based on the presence or absence of a Glu-Leu-Arg motif, known as the ‘ELR’ motif. ELR+ CXC-chemokines are angiogenic and preferentially promote the chemoattraction of neutrophils, while ELR- CXC-chemokines are angiostatic and preferentially promote lymphocyte migration. However, all CXC-chemokines stimulate the migration of several leukocytes through the activation of G-protein-coupled receptors (GPCRs, known as CXCRs). CXC-chemokines also promote cell survival, activate various leukocyte effector functions and induce gene expression. CXC-chemokines have therefore been associated with the pathogenesis of several respiratory diseases including asthma, COPD, IPF, ARDS, cancer and infectious diseases.