P2Y12 Receptor Localizes in the Renal Collecting Duct and Its Blockade Augments Arginine Vasopressin Action and Alleviates Nephrogenic Diabetes Insipidus

Abstract

P2Y12 receptor (P2Y12-R) signaling is mediated through Gi, ultimately reducing cellular cAMP levels. Because cAMP is a central modulator of arginine vasopressin (AVP)-induced water transport in the renal collecting duct (CD), we hypothesized that if expressed in the CD, P2Y12-R may play a role in renal handling of water in health and in nephrogenic diabetes insipidus. We found P2Y12-R mRNA expression in rat kidney, and immunolocalized its protein and aquaporin-2 (AQP2) in CD principal cells. Administration of clopidogrel bisulfate, an irreversible inhibitor of P2Y12-R, significantly increased urine concentration and AQP2 protein in the kidneys of Sprague-Dawley rats. Notably, clopidogrel did not alter urine concentration in Brattleboro rats that lack AVP. Clopidogrel administration also significantly ameliorated lithium-induced polyuria, improved urine concentrating ability and AQP2 protein abundance, and reversed the lithium-induced increase in free-water excretion, without decreasing blood or kidney tissue lithium levels. Clopidogrel administration also augmented the lithium-induced increase in urinary AVP excretion and suppressed the lithium-induced increase in urinary nitrates/nitrites (nitric oxide production) and 8-isoprostane (oxidative stress). Furthermore, selective blockade of P2Y12-R by the reversible antagonist PSB-0739 in primary cultures of rat inner medullary CD cells potentiated the expression of AQP2 and AQP3 mRNA, and cAMP production induced by dDAVP (desmopressin). In conclusion, pharmacologic blockade of renal P2Y12-R increases urinary concentrating ability by augmenting the effect of AVP on the kidney and ameliorates lithium-induced NDI by potentiating the action of AVP on the CD. This strategy may offer a novel and effective therapy for lithium-induced NDI.

Role of adenylyl cyclase 6 in the development of lithium-induced nephrogenic diabetes insipidus

“…For example, several previous studies implicating a role for reduced cAMP in the onset of Li-NDI did not measure cAMP levels in vivo (12,36), whereas a direct cause-effect correlation cannot be concluded from other models with diminished cAMP levels following Li + treatment (17) due to compensatory mechanisms, such as a negative-feedback response of cells to increased AVP levels (37). A strength of the current study was the use two different mouse models that lack AC6, the AC isoform mediating the majority of AVP-induced IM cAMP formation, allowing us to assess directly a role of cAMP in Li-NDI.…”

Prasugrel suppresses development of lithium-induced nephrogenic diabetes insipidus in mice

“…Unless otherwise stated, mice were housed in groups in conventional plastic cages with bedding and regulated light-dark cycles and had free access to food and drinking water. NDI was induced by the administration of LiCl by the methods established in our laboratory [10,[14][15][16]. Age-matched adult male mice were randomly divided into four groups (five mice/group).…”

“…In our studies we blocked the P2Y 12 receptor in rodents by the administration of clopidogrel bisulfate (CLPD) [10,16]. CLPD has been in the clinical use for about 19 years as an anticlotting drug by virtue of its ability to block the platelet P2Y 12 receptor (ADP receptor) irreversibly.…”

“…Recently, we discovered that ADP-activated P2Y 12 receptor is also expressed in the rodent kidney, and it may play a potential role in water handling by the kidney by opposing the action of AVP on the collecting duct [10]. Thus, it appears that the autocrine and/or paracrine actions of extracellular nucleotides through P2Y receptors constitute tonic inhibitory effect on water and sodium reabsorption mediated by the AVP and aldosterone.…”

“…However, currently, there are no FDA-approved selective antagonists of the P2Y 2 receptor, thus limiting our in vivo studies using pharmacological approach on this receptor. In contrast, the availability of FDAapproved and selective P2Y 12 receptor antagonists allowed us to demonstrate that its pharmacological blockade significantly ameliorates lithium-induced NDI in rodents [10,16]. These drugs are used to inhibit platelet ADP receptor and thus prevent acute episodes of cardiovascular or cerebrovascular events, such as heart attack and stroke, respectively.…”