RESUMEN
Background: Phosphodiesterase 10A (PDE10A) is expressed almost exclusively in the striatum and its inhibition is suggested to offer potential treatment in disorders associated with basal ganglia. We evaluated the selectivity, cytotoxicity, genotoxicity, pharmacokinetics and potential adverse effects of a novel PDE10A inhibitor, CPL500036, in vivo. Methods: The potency of CPL500036 was demonstrated by microfluidic technology, and selectivity was investigated in a radioligand binding assay against 44 targets. Cardiotoxicity in vitro was evaluated in human ether-a-go-go related gene (hERG)-potassium channel-overexpressing cells by the patch-clamp method and by assessing key parameters in 3D cardiac spheroids. Cytotoxicity was determined in H1299, HepG2 and SH-SY5Y cell lines. The Ames test was used for genotoxicity analyses. During in vivo studies, CPL500036 was administered by oral gavage. CPL500036 exposure were determined by liquid chromatography-tandem mass spectrometry and plasma protein binding was assessed. The bar test was employed to assess catalepsy. Prolactin and glucose levels in rat blood were measured by ELISAs and glucometers, respectively. Cardiovascular safety in vivo was investigated in dogs using a telemetry method. Results: CPL500036 inhibited PDE10A at an IC50 of 1 nM, and interacted only with the muscarinic M2 receptor as a negative allosteric modulator with an IC50 of 9.2 µM. Despite inhibiting hERG tail current at an IC25 of 3.2 µM, cardiovascular adverse effects were not observed in human cardiac 3D spheroids or in vivo. Cytotoxicity in vitro was observed only at > 60 µM and genotoxicity was not recorded during the Ames test. CPL500036 presented good bioavailability and penetration into the brain. CPL500036 elicited catalepsy at 0.6 mg/kg, but hyperprolactinemia or hyperglycemic effects were not observed in doses up to 3 mg/kg. Conclusion: CPL500036 is a potent, selective and orally bioavailable PDE10A inhibitor with a good safety profile distinct from marketed antipsychotics. CPL500036 may be a compelling drug candidate.
RESUMEN
One of the aims of the EU-funded Research and Innovation Action (RIA), titled "Ageing with Elegans" (AwE) is to enhance better understanding of the factors causing health and disease in aging and develop evidence-based preventive, diagnostic, therapeutic, and other strategies. The work package-5 of this project is focused on testing the effects of phytochemicals of natural and synthetic origin on aging, longevity, and health of human cells in vitro, after the initial screening using the animal model systems of nematodes and rats and mice. Accordingly, the first series of three compounds, rosmarinic acid (ROSM), ampelopsin (AMPEL), and amorfrutin-A (AMOR), were selected to test for their short-term and long-term effects on human skin fibroblasts undergoing aging and senescence in vitro. The lifelong modulatory effects of these compounds were tested individually at two doses (0.5 and 1.0 µM), selected after a short-term dose response check of a 20,000-fold range (0.01-200 µM). The results show that these compounds do have some beneficial effects in terms of supporting the long-term lifelong growth and enhanced stress tolerance of serially passaged cells. These effects seem to be achieved by reducing the extent of loss of telomeres, of 5-methyl-cytosine (5-mC) and of 5-hydroxymethyl-cytosine (5-hmC), by reducing the accumulation of oxidative DNA damage product 8-OHdG. There is also some indication that these compounds induce at least one of the stress responses in terms of the increased synthesis of heat shock protein Hsp70. Thus, these phytochemicals may be potential hormetins, which bring about their health beneficial effects by the phenomenon of mild stress-induced hormesis.
