Mast Cell Degranulation Increases Mouse Mast Cell Protease 4-Dependent Vasopressor Responses to Big Endothelin-1 But Not Angiotensin I

Mouse mast cell protease 4 (mMCP-4), the murine functional analog to the human chymase, is a serine protease synthesized and stored in mast cell secretory granules. Our previous studies reported physiologic and pathologic roles for mMCP-4 in the maturation and synthesis of the vasoactive peptide endothelin-1 (ET-1) from its precursor, big ET-1. The aim of this study was to investigate the impact of mast cell degranulation or stabilization on mMCP-4-dependent pressor responses after the administration of big ET-1 or angiotensin I (Ang I). In anesthetized mice, mast cell degranulation induced by compound 48/80 (C48/80) or stabilization by cromolyn enhanced or repressed, respectively, the dose-dependent vasopressor responses to big ET-1 in wild-type (WT) mice but not in mMCP-4 knockout mice in a chymase inhibitor (TY-51469)-sensitive fashion. In addition, mMCP-4-dependent hydrolysis of the fluorogenic substrate Suc-Leu-Leu-Val-Tyr-7-amino-4-methylcoumarin was depleted or enhanced in peritoneal mast cells isolated from mice pretreated with C48/80 or cromolyn, respectively. Furthermore, C48/80 or cromolyn markedly increased or abolished, respectively, ET-1 (1-31) conversion from exogenous big ET-1 in WT mice peritoneal fluid-isolated mast cells, in vitro. Finally, the vasopressor responses to Ang I were unaffected by mast cell activation or stabilization, whereas those induced by the angiotensin-converting enzyme-resistant Ang I analog, [Pro¹¹, D-Ala¹²] Ang I, were potentiated by C48/80. Altogether, the present study shows that mast cell activation enhances the mMCP-4-dependent vasoactive properties of big ET-1 but not Ang I in the mouse model. SIGNIFICANCE STATEMENT: The current work demonstrates a significant role for mast cell stability in the cardiovascular pharmacology of big endothelin-1 but not angiotensin I in the murine systemic circulation.

Endothelin: 30 Years From Discovery to Therapy

Discovered in 1987 as a potent endothelial cell-derived vasoconstrictor peptide, endothelin-1 (ET-1), the predominant member of the endothelin peptide family, is now recognized as a multifunctional peptide with cytokine-like activity contributing to almost all aspects of physiology and cell function. More than 30 000 scientific articles on endothelin were published over the past 3 decades, leading to the development and subsequent regulatory approval of a new class of therapeutics-the endothelin receptor antagonists (ERAs). This article reviews the history of the discovery of endothelin and its role in genetics, physiology, and disease. Here, we summarize the main clinical trials using ERAs and discuss the role of endothelin in cardiovascular diseases such as arterial hypertension, preecclampsia, coronary atherosclerosis, myocardial infarction in the absence of obstructive coronary artery disease (MINOCA) caused by spontaneous coronary artery dissection (SCAD), Takotsubo syndrome, and heart failure. We also discuss how endothelins contributes to diabetic kidney disease and focal segmental glomerulosclerosis, pulmonary arterial hypertension, as well as cancer, immune disorders, and allograft rejection (which all involve ET_A autoantibodies), and neurological diseases. The application of ERAs, dual endothelin receptor/angiotensin receptor antagonists (DARAs), selective ET_B agonists, novel biologics such as receptor-targeting antibodies, or immunization against ET_A receptors holds the potential to slow the progression or even reverse chronic noncommunicable diseases. Future clinical studies will show whether targeting endothelin receptors can prevent or reduce disability from disease and improve clinical outcome, quality of life, and survival in patients.