Mast cells: target and source of neuropeptides.

Mast cells, originating from bone marrow pluripotential cells are generally populated near to strategic locations of mammalian body. They store a wide variety of biologically active molecules in their granules and also can de novo synthesize an additional spectrum of mediators, depending on their microenvironment, phenotype and status. Mast cells have numerous receptors that can trigger a wide spectrum of cellular responses, some of them which can be preprogrammed against specific pathogens. Mast cells secrete mediators, go under total degranulation, or degranulate only some of the specific granules with required content according to the environmental conditions, pathogens or signaling molecules binding to their receptors. Mast cells are functionally multi faceted cells. A single cell can behave such as an immune cell, an endocrine cell and even as a sensorial neuron. In this context, mast cells can significantly influence inflammation, tissue remodeling, host defense and homeostasis. Specifically the mast cells proximal to nerve fibers, contain, secrete and respond to, several neuropeptides, suggesting many potential functions for mast cells in health and disease. Mast cells are target cells for neuropeptides and, they have distinct profiles of responsiveness to these molecules. This extends the flexibility of neurogenic signaling pathways via reciprocity. Those neuropeptides have direct and indirect effects on mast cells such as inducing or suppression of degranulation, triggering, modulation or amplification of mediator content and release. The exploration of interactions of mast cells and neurons is a promising field of study which may bring treatments to several diseases. Since mast cells seem to form the major link between neurons and inflammation via neuropeptides, mast cell and mast cell mediator connection may lead to a better understanding of the autocrine, paracrine, and neuro-immune-endocrine systems in physiology and physiopathology. Therefore, mast cell manipulator drug designs, capable of granular content modulation, with effects on, selective mediator release, activity and, ablation of mast cells, would be very beneficial for the treatment of various diseases that mast cells may be involved in.