title: Phosphodiesterase inhibition with tadalafil provides longer and sustained protection of stem cells.
abstract: We hypothesized that inhibition of the cGMP-specific enzyme phosphodiesterase 5A (PDE5A) promoted cGMP/protein kinase G (PKG) activity to condition stem cells for enhanced survival and proliferation. One-time tadalafil treatment (1 μM for 30 min) of mesenchymal stem cells ((Tada)MSCs) provided sustained protection of cells for 36 h. Higher cGMP activity with concomitantly increased PKG1 activity was observed in (Tada)MSCs, which peaked within 12 h after tadalafil treatment. Pretreatment with PKG1 blockers (1 μM KT-5823 or 20 nM K-252a) or transduction with adenoviral PKG1-short-hairpin RNA abolished tadalafil-induced cytoprotection of the cells. A higher proliferation rate was observed in (Tada)MSCs compared with nontreated MSCs ((Cont)MSCs). In a rat model of acute myocardial infarction, (Tada)MSCs transplanted 0 and 24 h after tadalafil treatment showed higher survival compared with (Cont)MSCs on day 2 and day 4 after engraftment. (Tada)MSCs transplanted 48 h after tadalafil treatment lost their protection on both day 2 and day 4 after engraftment, and their rate of survival was similar to (Cont)MSCs. Reduced terminal dUTP nick end-labeling positivity (P < 0.01 vs. (Cont)MSCs) and higher proliferation of (Tada)MSCs (P < 0.01 vs. (Cont)MSCs) was observed in the infarcted heart. Fluorescence immunostaining revealed neomyogenesis in both the infarct and peri-infarct areas. Blood vessel density was significantly increased in group 2 compared with group 1. Transthoracic echocardiographic heart function revealed significant preservation of the indexes of left ventricle contractility and attenuation of remodeling in (Tada)MSC-engrafted animal hearts (group 2) compared with (Cont)MSCs (group 1). PDE5A inhibition using long-acting tadalafil is an innovative approach to promote stem cell survival and proliferation in the infarcted heart.
authors.affiliation: Department of Pathology, University of Cincinnati, Cincinnati, Ohio 45267-0529, USA.
authors.forename: Husnain Kh
authors.initials: HKh
authors.lastname: Haider
authors.forename: Yun-Jung
authors.initials: YJ
authors.lastname: Lee
authors.forename: Shujia
authors.initials: S
authors.lastname: Jiang
authors.forename: Rafeeq P H
authors.initials: RP
authors.lastname: Ahmed
authors.forename: Mok
authors.initials: M
authors.lastname: Ryon
authors.forename: Muhammad
authors.initials: M
authors.lastname: Ashraf
mesh_terms: D000818:Animals; D002243:Carbolines / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism; D017869:Cyclic GMP-Dependent Protein Kinases / Q000378:metabolism; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; D004305:Dose-Response Relationship, Drug; D006085:Graft Survival / Q000187:drug effects; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D023421:Models, Animal; D009203:Myocardial Infarction / Q000601:surgery*; D018919:Neovascularization, Physiologic / Q000502:physiology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344; D000068581:Tadalafil; D013997:Time Factors
chemical_list: D002243:Carbolines; D010726:Phosphodiesterase Inhibitors; D000068581:Tadalafil; D017869:Cyclic GMP-Dependent Protein Kinases; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; C517384:Pde5a protein, rat; D006152:Cyclic GMP