Adenosine 5‘-O-(1-Boranotriphosphate) Derivatives as Novel P2Y₁ Receptor Agonists

Abstract

P2-receptors (P2-Rs) represent important targets for novel drug development. Most ATP analogues proposed as potential drug candidates have shortcomings such as limited receptor-selectivity and limited stability that justify the search for new P2-R agonists. Therefore, a novel series of nucleotides based on the adenosine 5'-O-(1-boranotriphosphate) (ATP-alpha-B) scaffold was developed and tested as P2Y(1)-R agonists. An efficient four-step one-pot synthesis of several ATP-alpha-B analogues from the corresponding nucleosides was developed, as well as a facile method for the separation of the diastereoisomers (A and B isomers) of the chiral products. The potency of the new analogues as P2Y(1)-R agonists was evaluated by the agonist-induced Ca2+ release of HEK 293 cells stably transfected with rat-brain P2Y(1)-R. ATP-alpha-B A isomer was equipotent with ATP (EC50 = 2 x 10(-7) M). However, 2-MeS- and 2-Cl- substitutions on ATP-alpha-B (A isomer) increased the potency of the agonist up to 100-fold, with EC50 values of 4.5 x 10(-9) and 3.6 x 10(-9) M, compared to that of the ATP-alpha-B (A isomer). Diastereoisomers A of all ATP-alpha-B analogues were more potent in inducing Ca2+ release than the corresponding B counterparts, with a 20-fold difference for 2-MeS-ATP-alpha-B analogues. The chemical stability of the new P2Y(1)-R agonists was evaluated by 31P NMR under physiological and gastric-juice pH values at 37 degrees C, with rates of hydrolysis of 2-MeS-ATP-alpha-B of 1.38 x 10(-7) s-1 (t1/2 of 1395 h) and 3.24 x 10(-5) s-1 (t1/2 = 5.9 h), respectively. The enzymatic stability of the new analogues toward spleen NTPDase was evaluated. Most of the new analogues were poor substrates for the NTPDase, with ATP-alpha-B (A isomer) hydrolysis being 5% of the hydrolysis rate of ATP. Diastereoisomers A and B exhibited different stability, with A isomers being significantly more stable, up to 9-fold. Furthermore, A isomers that are potent P2Y(1)-R agonists barely interact with NTPDase, thus exhibiting protein selectivity. Therefore, on the basis of our findings, the new, highly water-soluble, P2Y(1)-R agonists may be considered as potentially promising drug candidates.

Activation of P2X7 receptors in glial satellite cells reduces pain through downregulation of P2X3 receptors in nociceptive neurons

“…In contrast to P2X3Rs and P2Y1Rs, P2X7Rs require a much higher concentration of ATP for their activation (1,33). How can ATP activate P2X7Rs without first stimulating P2X3Rs and P2Y1Rs?…”

International Union of Pharmacology LVIII: Update on the P2Y G Protein-Coupled Nucleotide Receptors: From Molecular Mechanisms and Pathophysiology to Therapy

“…Thus, 5Ј-(1-boranotriphosphate) derivatives such as the 2-methylthio derivative (11) have been found to potently activate the P2Y 1 receptor (Nahum et al, 2002). Because the 1-boranotriphosphate moiety is chiral, it was possible to separate two stable isomers in this series.…”

Purinergic receptors and gastrointestinal secretomotor function

“…A potent and selective antagonist is 2′-deoxy-N6-methyladenosine-3′5′-bisphosphate (MRS2179) or MRS2279. Adenosine 5′-O-(1-boranotriphosphate) (ATP-α-B) derivatives are novel P2Y 1 receptor agonists that may be of potential clinical relevance [78].…”