1 Lomonosov Moscow State University, Moscow, Russia; 2 Koltsov Institute of Developmental Biology RAS, Moscow, Russia; firstname.lastname@example.org
The maintaining of homeostasis is provided in a great measure with interaction of neural, immune and endocrine systems. Mast cells (MC) play a coordinating role in this interaction because of their ability to produce the wide spectrum of biologically active substances. Early we have found that regulatory peptide from glyprolines’ family PGP stabilized MC and significantly reduced the secretion of proinflammatory mediators - histamine and β-hexosaminidase. The mechanism of MC stabilization by PGP is not clear. It is known that the increase of calcium level in cytoplasm plays a defining role in activation of MC (change of shape, signaling, synthesis and secretion of mediators). In this work we have investigated the influence of PGP on calcium level in cytoplasm of rat MC under activation.
We have found that activation of MC by synacten (synthetic analog of ACTH) led to significant (2,5-fold) increase of calcium level in cytoplasm. It turned to the normal level in a minute. In MC which were preliminary treated with PGP the level of calcium increased only by 25% and also turned to the norm in a minute after activation. But there was no such dramatic increase of calcium level in MC cytoplasm in calcium-free buffer.
The preliminary treatment of MC with PGP didn’t prevent the increase of calcium level in cytoplasm under their activation by compound 48/80. And the level of calcium in cytoplasm increased in calcium-free buffer as well as in standard buffer. This data suggests that calcium efflux from intracellular storages plays a significant role in activation of MC by compound 48/80.
Thus, the stabilizing effect of PGP on MC can be based on its ability to prevent the increase of intracellular calcium level. The stabilization of MC with PGP is depends of the mechanism of their activation. It is possible that stabilization can be realized through the interaction of peptide with membrane structures of MC and, as a result, through the blockade of intracellular calcium level increase and the decrease of MC secretion.