Targeted Inhibition of Phosphodiesterase (PDE) 4 As a Novel Therapy to Increase Endothelial Cell cAMP and Trigger Weibel Palade Body Exocytosis

Background Desmopressin (DDAVP) is widely used in the treatment of VWD and other bleeding disorders. DDAVP activates V2 receptors (V2R) on endothelial cells (EC) to stimulate cAMP generation and Weibel-Palade body (WPB) exocytosis. However, DDAVP has inherent limitations, including lack of oral form...

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Bibliographic Details
Published in:Blood 2023-11, Vol.142 (Supplement 1), p.3975-3975
Main Authors: Doherty, Dearbhla, Karampini, Ellie, Byrne, Ciara, Schoen, Ingmar, Preston, Roger J.S, O'Sullivan, Jamie M, Lavin, Michelle, O'Donnell, James
Format: Article
Language:English
Online Access:Get full text
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Summary:Background Desmopressin (DDAVP) is widely used in the treatment of VWD and other bleeding disorders. DDAVP activates V2 receptors (V2R) on endothelial cells (EC) to stimulate cAMP generation and Weibel-Palade body (WPB) exocytosis. However, DDAVP has inherent limitations, including lack of oral formulation, side-effects related to renal V2R agonism and sub-optimal responses in some patients. Aims To identify previously approved drugs with capacity to trigger cAMP-dependent WPB secretion in EC to repurpose as novel hemostatic therapeutic agents. Methods Candidate agents were identified by mechanistic screening of FDA and EMA-approved drug databases and rationalized for translational relevance. For each class, prototypical drugs were tested in vitro for capacity to induce VWF release from macrovascular (HUVEC) and microvascular (HMVEC-L) EC (VWF antigen [Ag], propeptide [pp] and collagen binding [CB] in supernatant at 1 hour, expressed as fold increase relative to untreated control [NC]). VWF string formation on the surface of treated EC under flow conditions was determined using fluorescent anti-VWF antibodies and confocal microscopy. Finally, the effects of candidates on platelet aggregation were determined by light transmission aggregometry (LTA). Results and Discussion Mechanistic screening and preliminary in vitro evaluation determined a lead candidate drug class: PDE-4 inhibitors. Previous studies have shown that cAMP-hydrolyzing PDE isoforms 2, 3 and 4 are expressed in EC and that non-selective PDE inhibition (PDE-I) with IBMX alone can elevate cAMP in EC sufficiently to induce VWF release. Consistently, we observed that treatment of EC with IBMX significantly enhanced VWF secretion (median fold increase VWF:Ag vs NC:1.49, p0.999, Fig.1). In contrast, selective PDE-4 inhibition with Roflumilast (ROF) resulted in a dose-dependent increase in VWF:Ag secretion in both HUVEC (1.51 fold, p
ISSN:0006-4971
1528-0020
DOI:10.1182/blood-2023-178581