Catestatin has been detected in suprabasal and granular keratinocytes

and, to a lesser extent, in the dermis.4 Given that catestatin Tyrosine Kinase Inhibitor Library in vivo expression is markedly increased during cutaneous inflammation or skin injury where mast cells accumulate,29 direct contact may occur between catestatin and mast cells, resulting in mast cell activation. We also herein demonstrated that wild-type catestatin and its variants caused significant increases in the mRNA expression levels of various cytokines and chemokines, but only enhanced the protein levels of GM-CSF, MCP-1/CCL2, MIP-1α/CCL3 and MIP-1β/CCL4. This implies that catestatin-induced human mast cell stimulation may be selective for a limited number of inflammatory mediators. Indeed, there are numerous reports highlighting the inflammatory roles of GM-CSF, MCP-1/CCL2, MIP-1α/CCL3 and MIP-1β/CCL4. It is know that GM-CSF is involved in allergic diseases via its promotion of the antigen-processing activity of Langerhans and dendritic cells, and takes part in the maintenance of the chronic inflammatory process in atopic dermatitis.32 The chemokines MIP-1α/CCL3 and MIP-1β/CCL4 are regarded as markers of local skin inflammatory responses,33 and are critical in both acute inflammation and chronic inflammatory diseases.34,35 Furthermore, MIP-1α/CCL3 enhances

the migration of T cells, macrophages, eosinophils and neutrophils in human skin.36 As for MCP-1/CCL2, it displays chemoattractant activity for numerous inflammatory and immune cells, and participates in the pathogenesis of systemic sclerosis and fibrotic processes.36,37 Smoothened Agonist purchase In addition, MCP-1/CCL2 is up-regulated in the epidermis of the chronic lesional skin of atopic

dermatitis and psoriasis patients.38 Taken together, our results suggest that in addition to Methane monooxygenase histamine and eicosanoid release, catestatins may also participate in the regulation of cutaneous inflammatory processes by promoting the production of inflammatory cytokines and chemokines by mast cells. To understand the molecular mechanisms underlying the activities of catestatin peptides, we investigated the requirement for G-proteins and PLC, as their roles in mast cell activation have been reported previously,15,16 and involvement of G-protein pathway has been claimed in catestatin-stimulated rat mast cells and human monocytes.9,23 The G-protein inhibitor pertussis toxin and the PLC inhibitor U-73122 showed inhibitory effects on all catestatin-mediated mast cell functions, implying that catestatins act via G-protein and PLC pathways to exert their stimulatory effects on human mast cells. Although both pertussis toxin and U-73122 had significant inhibitory effects on catestatin activity, the inhibition was not complete, suggesting the presence of additional pathways such as another activating receptor or transactivation.