Molecular cues guiding inflammatory responses

Alarm signals generated at inflammatory foci reach the vascular lumen to attract immune cells towards the affected tissue. Different leucocyte subsets decipher and integrate these complex signals in order to make adequate decisions for their migration towards the inflamed tissue. Soluble cues (cytokines and chemokines) and membrane receptors in both endothelium and leucocytes orchestrate the coordinated recruitment of specific inflammatory cell subsets. All these molecules are spatio-temporally organized in specialized structures at the luminal side of endothelium and the leucocyte membrane or are generated as chemical gradients in the damaged tissue. Thus, the repertoire of chemokines and their receptors as well as adhesion molecules expressed by each leucocyte subset determine their recruitment for participation in specific inflammatory pathologies. Whenever inflammatory signals are altered or misprocessed, inflammation can become chronic, causing extensive tissue damage. To combat chronic inflammation and autoimmune diseases, novel therapeutic strategies attempt to silence the predominant signals in each inflammatory scenario. In this review, we provide a general overview of all these aspects related to the molecular regulation of leucocyte guidance in inflammatory responses.