Inhibition of the mevalonate pathway by simvastatin interferes with mast cell degranulation by disrupting the interaction between Rab27a and double C2 alpha proteins.

Statins are well-known inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, which block the mevalonate pathway. The activity of statins not only decreases cholesterol levels but also ameliorates inflammation and modulates the immune system. In this study, we investigated the effects of simvastatin on histamine release using rat basophilic leukaemia (RBL-2H3) cells, and examined its interaction with proteins involved in the exocytosis process. Treatment with simvastatin for 24h inhibited histamine release in RBL-2H3 cells in a concentration-dependent manner after stimulation with dinitrophenylated bovine serum albumin (DNP-BSA, as an antigen), ionomycin (a calcium ion [Ca