Chromogranin A binds to αvβ6-integrin and promotes wound healing in mice

• Published in: Cellular and molecular life sciences : CMLS 2012-08, Vol.69 (16), p.2791-2803
• Main Authors: Curnis, Flavio, Gasparri, Anna Maria, Longhi, Renato, Colombo, Barbara, D’Alessio, Silvia, Pastorino, Fabio, Ponzoni, Mirco, Corti, Angelo
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antigens, Neoplasm - metabolism; Binding, Competitive; Biochemistry; Biomedical and Life Sciences; Biomedicine; Cell Adhesion - physiology; Cell Biology; Cell Movement - physiology; Cells, Cultured; Chromogranin A - metabolism; Fibroblasts - cytology; Fibroblasts - metabolism; Humans; Integrins - metabolism; Keratinocytes - cytology; Keratinocytes - metabolism; Life Sciences; Mice; Mice, Inbred C57BL; Molecular Sequence Data; Oligopeptides - metabolism; Peptide Fragments - metabolism; Research Article; Secretin - analogs & derivatives; Secretin - metabolism; Sequence Homology, Amino Acid; Skin - cytology; Skin - metabolism; Wound Healing - physiology
• ISSN: 1420-682X; 1420-9071
• DOI: 10.1007/s00018-012-0955-z

Chromogranin A (CgA), a secretory protein expressed by many neuroendocrine cells, neurons, cardiomyocytes, and keratinocytes, is the precursor of various peptides that regulate the carbohydrate/lipid metabolism and the cardiovascular system. We have found that CgA, locally administered to injured mice, can accelerate keratinocyte proliferation and wound healing. This biological activity was abolished by the Asp 45 Glu mutation. CgA and its N-terminal fragments, but not the corresponding Asp 45 Glu mutants, could selectively recognize the αvβ6-integrin on keratinocytes (a cell-adhesion receptor that is up-regulated during wound healing) and regulate keratinocyte adhesion, proliferation, and migration. No binding was observed to other integrins such as αvβ3, αvβ5, αvβ8, α5β1, α1β1, α3β1, α6β4, α6β7 and α9β1. Structure–activity studies showed that the entire CgA 39–63 region is crucial for αvβ6 recognition ( K i  = 7 nM). This region contains an RGD site (residues CgA 43–45 ) followed by an amphipathic α-helix (residues CgA 47–63 ), both crucial for binding affinity and selectivity. These results suggest that the interaction of the RGD/α-helix motif of CgA with αvβ6 regulates keratinocyte physiology in wound healing.