Genomic stability of pulmonary artery endothelial colony-forming cells in culture.

Pulmonary vascular remodeling, including proliferation and migration of pulmonary artery endothelial cells (PAEC), is a pathologic hallmark of pulmonary arterial hypertension (PAH). Multiple studies have shown evidence of increased levels of DNA damage and lineage-specific genetic changes in PAH lung vascular cells, suggesting increased genomic instability. Highly proliferative endothelial colony-forming cell (ECFC) clones can be isolated from PAEC.

Pulmonary artery endothelium resident endothelial colony-forming cells in pulmonary arterial hypertension.

Proliferative pulmonary vascular remodeling is the pathologic hallmark of pulmonary arterial hypertension (PAH) that ultimately leads to right heart failure and death. Highly proliferative endothelial cells known as endothelial colony-forming cells (ECFC) participate in vascular homeostasis in health as well as in pathological angiogenic remodeling in disease. ECFC are distinguished by the capacity to clonally proliferate from a single cell.

Pro-angiogenic hematopoietic progenitor cells and endothelial colony-forming cells in pathological angiogenesis of bronchial and pulmonary circulation.

Dysregulation of angiogenesis is a common feature of many disease processes. Vascular remodeling is believed to depend on the participation of endothelial progenitor cells, but the identification of endothelial progenitors in postnatal neovascularization remains elusive. Current understanding posits a role for circulating pro-angiogenic hematopoietic cells that interact with local endothelial cells to establish an environment that favors angiogenesis in physiologic and pathophysiologic responses.

2-triazole-substituted adenosines: a new class of selective A3 adenosine receptor agonists, partial agonists, and antagonists.

"Click chemistry" was explored to synthesize two series of 2-(1,2,3-triazolyl)adenosine derivatives (1-14). Binding affinity at the human A(1), A(2A), and A(3)ARs (adenosine receptors) and relative efficacy at the A(3)AR were determined. Some triazol-1-yl analogues showed A(3)AR affinity in the low nanomolar range, a high ratio of A(3)/A(2A) selectivity, and a moderate-to-high A(3)/A(1) ratio.

Action of nucleosides and nucleotides at 7 transmembrane-spanning receptors.

Ribose ring-constrained nucleosides and nucleotides to act at cell-surface purine recesptors have been designed and synthesized. At the P2Y1 nucleotide receptor and the A3 adenosine receptor (AR) the North envelope conformation of ribose is highly preferred. We have applied mutagenesis and rhodopsin-based homology modeling to the study of purine receptors and used the structural insights gained to assist in the design of novel ligands.

Orthogonal activation of the reengineered A3 adenosine receptor (neoceptor) using tailored nucleoside agonists.

An alternative approach to overcome the inherent lack of specificity of conventional agonist therapy can be the reengineering of the GPCRs and their agonists. A reengineered receptor (neoceptor) could be selectively activated by a modified agonist, but not by the endogenous agonist. Assisted by rhodopsin-based molecular modeling, we pinpointed mutations of the A(3) adenosine receptor (AR) for selective affinity enhancement following complementary modifications of adenosine.

Design, synthesis, and biological activity of N6-substituted-4'-thioadenosines at the human A3 adenosine receptor.

A large series of N6-substituted-4'-thioadenosines were synthesized starting from D-gulonic-gamma-lactone, and structure-activity relationships were studied at the human A3 and other subtypes of adenosine receptors (ARs). 2-Chloro-substituted and 2-H analogues were compared. 2-Chloro-N6-methyl-4'-thioadenosine 19b was a highly potent and selective agonist (Ki=0.

Nucleoside modification and concerted mutagenesis of the human A3 adenosine receptor to probe interactions between the 2-position of adenosine analogs and Gln167 in the second extracellular loop.

Residues of the second extracellular loop are believed to be important for ligand recognition in adenosine receptors. Molecular modeling studies have suggested that one such residue, Gln167 of the human A3 receptor, is in proximity to the C2 moiety of some adenosine analogs when bound. Here this putative interaction was systematically explored using a neoceptor strategy, i.

Structure-activity relationships of 2-chloro-N6-substituted-4'-thioadenosine-5'-uronamides as highly potent and selective agonists at the human A3 adenosine receptor.

We have established structure-activity relationships of novel 4'-thionucleoside analogues as the A(3) adenosine receptor (AR) agonists. Binding affinity, selectivity toward other AR subtypes, and efficacy in inhibition of adenylate cyclase were studied. From this study, 2-chloro-N(6)-methyl-4'-thioadenosine-5'-methyluronamide (36a) emerged as the most potent and selective agonist at the human A(3) AR.

Semi-rational design of (north)-methanocarba nucleosides as dual acting A(1) and A(3) adenosine receptor agonists: novel prototypes for cardioprotection.

Ring-constrained adenosine analogues have been designed to act as dual agonists at tissue-protective A(1) and A(3) adenosine receptors (ARs). 9-Ribosides transformed into the ring-constrained (N)-methanocarba-2-chloro-5'-uronamides consistently lost affinity at A(1)/A(2A)ARs and gained at A(3)AR. Among 9-riboside derivatives, only N(6)-cyclopentyl and 7-norbornyl moieties were extrapolated for mixed A(1)/A(3) selectivity and rat/human A(3)AR equipotency.

(N)-methanocarba 2,N6-disubstituted adenine nucleosides as highly potent and selective A3 adenosine receptor agonists.

A series of ring-constrained (N)-methanocarba-5'-uronamide 2,N(6)-disubstituted adenine nucleosides have been synthesized via Mitsunobu condensation of the nucleobase precursor with a pseudosugar ring containing a 5'-ester functionality. Following appropriate functionalization of the adenine ring, the ester group was converted to the 5'-N-methylamide. The compounds, mainly 2-chloro-substituted derivatives, were tested in both binding and functional assays at human adenosine receptors (ARs), and many were found to be highly potent and selective A(3)AR agonists.

A neoceptor approach to unraveling microscopic interactions between the human A2A adenosine receptor and its agonists.

Strategically mutated neoceptors, e.g., with anionic residues in TMs 3 and 7 intended for pairing with positively charged amine-modified nucleosides, were derived from the antiinflammatory A(2A) adenosine receptor (AR).

Modulation of adenosine receptor affinity and intrinsic efficacy in adenine nucleosides substituted at the 2-position.

We studied the structural determinants of binding affinity and efficacy of adenosine receptor (AR) agonists. Substituents at the 2-position of adenosine were combined with N(6)-substitutions known to enhance human A(3)AR affinity. Selectivity of binding of the analogues and their functional effects on cAMP production were studied using recombinant human A(1), A(2A), A(2B), and A(3)ARs.

Exploring distal regions of the A3 adenosine receptor binding site: sterically constrained N6-(2-phenylethyl)adenosine derivatives as potent ligands.

We synthesized phenyl ring-substituted analogues of N(6)-(1S,2R)-(2-phenyl-1-cyclopropyl)adenosine, which is highly potent in binding to the human A(3)AR with a Ki value of 0.63 nM. The effects of these structural changes on affinity at human and rat adenosine receptors and on intrinsic efficacy at the hA(3)AR were measured.