A G-protein-biased S1P1 agonist, SAR247799, improved LVH and diastolic function in a rat model of metabolic syndrome.

AIM: Heart failure with preserved ejection fraction (HFpEF) is a major cause of death worldwide with no approved treatment. Left ventricular hypertrophy (LVH) and diastolic dysfunction represent the structural and functional components of HFpEF, respectively. Endothelial dysfunction is prevalent in HFpEF and predicts cardiovascular events. We investigated if SAR247799, a G-protein-biased sphingosine-1-phosphate receptor 1 (S1P1) agonist with endothelial-protective properties, could improve cardiac and renal functions in a rat model of metabolic syndrome LVH and diastolic function. METHODS: 31- and 65-week-old obese ZSF1 (Ob-ZSF1) rats, representing adult and aged animals with LVH and diastolic dysfunction, were randomized to a chow diet containing 0.025% (w/w) of SAR247799, or control (CTRL) chow for 4 weeks. Age-matched lean ZSF1 (Le-ZSF1) rats were fed control chow. Echocardiography, telemetry, biochemical and histological analysis were performed to evaluate the effect of SAR247799. RESULTS: Echocardiography revealed that Ob-ZSF1 rats, in contrast to Le-ZSF1 rats, developed progressive diastolic dysfunction and cardiac hypertrophy with age. SAR247799 blunted the progression of diastolic dysfunction in adult and aged animals: in adult animals E/e' was evaluated at 21.8 ± 1.4 for Ob-ZSF1-CTRL, 19.5 ± 1.2 for Ob-ZSF1-SAR247799 p<0.01, and 19.5 ± 2.3 for Le-ZSF1-CTRL (median ± IQR). In aged animals E/e' was evaluated at 23.15 ± 4.45 for Ob-ZSF1-CTRL, 19.5 ± 5 for Ob-ZSF1-SAR247799 p<0.01, and 16.69 ± 1.7 for Le-ZSF1-CTRL, p<0.01 (median ± IQR). In aged animals, SAR247799 reduced cardiac hypertrophy (g/mm mean ± SEM of heart weight/tibia length 0.053 ± 0.001 for Ob-ZSF1-CTRL vs 0.046 ± 0.002 for Ob-ZSF1-SAR247799 p<0.01, Le-ZSF1-CTRL 0.035 ± 0.001) and myocardial perivascular collagen content (p<0.001), independently of any changes in microvascular density. In adult animals, SAR247799 improved endothelial function as assessed by the very low frequency bands of systolic blood pressure variability (mean ± SEM 67.8 ± 3.41 for Ob-ZSF1-CTRL 55.8 ± 4.27 or Ob-ZSF1-SAR247799, p<0.05 and 57.3 ± 1.82 Le-ZSF1-CTRL), independently of any modification of arterial blood pressure. In aged animals, SAR247799 reduced urinary protein/creatinine ratio, an index of glomerular injury, (10.3 ± 0.621 vs 8.17 ± 0.231 for Ob-ZSF1-CTRL vs Ob-ZSF1-SAR247799, respectively, p<0.05 and 0.294 ± 0.029 for Le-ZSF1-CTRL, mean ± SEM) and the fractional excretion of electrolytes. Circulating lymphocytes were not decreased by SAR247799, confirming lack of S1P1 desensitization. CONCLUSIONS: These experimental findings suggest that S1P1 activation with SAR247799 may be considered as a new therapeutic approach for LVH and diastolic dysfunction, major components of HFpEF.

High Glucose Activates YAP Signaling to Promote Vascular Inflammation.

BACKGROUND AND AIMS: The YAP/TAZ signaling is known to regulate endothelial activation and vascular inflammation in response to shear stress. Moreover, YAP/TAZ signaling plays a role in the progression of cancers and renal damage associated with diabetes. However, whether YAP/TAZ signaling is also implicated in diabetes-associated vascular complications is not known. METHODS: The effect of high glucose on YAP/TAZ signaling was firstly evaluated in vitro on endothelial cells cultured under static conditions or subjected to shear stress (either laminar or oscillatory flow). The impact of diabetes on YAP/TAZ signaling was additionally assessed in vivo in db/db mice. RESULTS: In vitro, we found that YAP was dephosphorylated/activated by high glucose in endothelial cells, thus leading to increased endothelial inflammation and monocyte attachment. Moreover, YAP was further activated when high glucose was combined to laminar flow conditions. YAP was also activated by oscillatory flow conditions but, in contrast, high glucose did not exert any additional effect. Interestingly, inhibition of YAP reduced endothelial inflammation and monocyte attachment. Finally, we found that YAP is also activated in the vascular wall of diabetic mice, where inflammatory markers are also increased. CONCLUSION: With the current study we demonstrated that YAP signaling is activated by high glucose in endothelial cells in vitro and in the vasculature of diabetic mice, and we pinpointed YAP as a regulator of high glucose-mediated endothelial inflammation and monocyte attachment. YAP inhibition may represent a potential therapeutic opportunity to improve diabetes-associated vascular complications.

Lipoprotein(a) Cellular Uptake Ex Vivo and Hepatic Capture In Vivo Is Insensitive to PCSK9 Inhibition With Alirocumab.

Lipoprotein(a) (Lp[a]) is the most common genetically inherited risk factor for cardiovascular disease. Many aspects of Lp(a) metabolism remain unknown. We assessed the uptake of fluorescent Lp(a) in primary human lymphocytes as well as Lp(a) hepatic capture in a mouse model in which endogenous hepatocytes have been ablated and replaced with human ones. Modulation of LDLR expression with the PCSK9 inhibitor alirocumab did not alter the cellular or the hepatic uptake of Lp(a), demonstrating that the LDL receptor is not a major route for Lp(a) plasma clearance. These results have clinical implications because they underpin why statins are not efficient at reducing Lp(a).

The selective GSK3 inhibitor, SAR502250, displays neuroprotective activity and attenuates behavioral impairments in models of neuropsychiatric symptoms of Alzheimer's disease in rodents.

Glycogen synthase kinase 3 (GSK3) has been identified as a promising target for the treatment of Alzheimer's disease (AD), where abnormal activation of this enzyme has been associated with hyperphosphorylation of tau proteins. This study describes the effects of the selective GSK3 inhibitor, SAR502250, in models of neuroprotection and neuropsychiatric symptoms (NPS) associated with AD. In P301L human tau transgenic mice, SAR502250 attenuated tau hyperphosphorylation in the cortex and spinal cord. SAR502250 prevented the increase in neuronal cell death in rat embryonic hippocampal neurons following application of the neurotoxic peptide, Aß25-35. In behavioral studies, SAR502250 improved the cognitive deficit in aged transgenic APP(SW)/Tau(VLW) mice or in adult mice after infusion of Aß25-35. It attenuated aggression in the mouse defense test battery and improved depressive-like state of mice in the chronic mild stress procedure after 4 weeks of treatment. Moreover, SAR502250 decreased hyperactivity produced by psychostimulants. In contrast, the drug failed to modify anxiety-related behaviors or sensorimotor gating deficit. This profile confirms the neuroprotective effects of GSK3 inhibitors and suggests an additional potential in the treatment of some NPS associated with AD.

Selective blockade of the hydrolysis of the endocannabinoid 2-arachidonoylglycerol impairs learning and memory performance while producing antinociceptive activity in rodents.

Monoacylglycerol lipase (MAGL) represents a primary degradation enzyme of the endogenous cannabinoid (eCB), 2-arachidonoyglycerol (2-AG). This study reports a potent covalent MAGL inhibitor, SAR127303. The compound behaves as a selective and competitive inhibitor of mouse and human MAGL, which potently elevates hippocampal levels of 2-AG in mice. In vivo, SAR127303 produces antinociceptive effects in assays of inflammatory and visceral pain. In addition, the drug alters learning performance in several assays related to episodic, working and spatial memory. Moreover, long term potentiation (LTP) of CA1 synaptic transmission and acetylcholine release in the hippocampus, two hallmarks of memory function, are both decreased by SAR127303. Although inactive in acute seizure tests, repeated administration of SAR127303 delays the acquisition and decreases kindled seizures in mice, indicating that the drug slows down epileptogenesis, a finding deserving further investigation to evaluate the potential of MAGL inhibitors as antiepileptics. However, the observation that 2-AG hydrolysis blockade alters learning and memory performance, suggests that such drugs may have limited value as therapeutic agents.

The CRF1 receptor antagonist SSR125543 prevents stress-induced long-lasting sleep disturbances in a mouse model of PTSD: comparison with paroxetine and d-cycloserine.

The selective CRF1 (corticotropin releasing factor type 1) receptor antagonist SSR125543 has been previously shown to attenuate the long-term behavioral and electrophysiological effects produced by traumatic stress exposure in mice. Sleep disturbances are one of the most commonly reported symptoms by people with post-traumatic stress disorder (PTSD). The present study aims at investigating whether SSR125543 (10 mg/kg/day/i.p. for 2 weeks) is able to attenuate sleep/wakefulness impairment induced by traumatic stress exposure in a model of PTSD in mice using electroencephalographic (EEG) analysis. Effects of SSR125543 were compared to those of the 5-HT reuptake inhibitor, paroxetine (10 mg/kg/day/i.p.), and the partial N-methyl-d-aspartate (NMDA) receptor agonist, d-cycloserine (10 mg/kg/day/i.p.), two compounds which have demonstrated clinical efficacy against PTSD. Baseline EEG recording was performed in the home cage for 6h prior to the application of two electric foot-shocks of 1.5 mA. Drugs were administered from day 1 post-stress to the day preceding the second EEG recording session, performed 14 days later. Results showed that at day 14 post-stress, shocked mice displayed sleep fragmentation as shown by an increase in the occurrence of both non-rapid eye movement (NREM) sleep and wakefulness bouts. The duration of wakefulness, NREM and REM sleep were not significantly affected. The stress-induced effects were prevented by repeated administration of SSR125543, paroxetine and D-cycloserine. These findings confirm further that the CRF1 receptor antagonist SSR125543 is able to attenuate the deleterious effects of traumatic stress exposure.

Mice deficient in cryptochrome 1 (cry1 (-/-)) exhibit resistance to obesity induced by a high-fat diet.

Disruption of circadian clock enhances the risk of metabolic syndrome, obesity, and type 2 diabetes. Circadian clocks rely on a highly regulated network of transcriptional and translational loops that drive clock-controlled gene expression. Among these transcribed clock genes are cryptochrome (CRY) family members, which comprise Cry1 and Cry2. While the metabolic effects of deletion of several core components of the clock gene machinery have been well characterized, those of selective inactivation of Cry1 or Cry2 genes have not been described. In this study, we demonstrate that ablation of Cry1, but not Cry2, prevents high-fat diet (HFD)-induced obesity in mice. Despite similar caloric intake, Cry1 (-/-) mice on HFD gained markedly less weight (-18%) at the end of the 16-week experiment and displayed reduced fat accumulation compared to wild-type (WT) littermates (-61%), suggesting increased energy expenditure. Analysis of serum lipid and glucose profiles showed no difference between Cry1 (-/-) and WT mice. Both Cry1 (-/-) and Cry2 (-/-) mice are indistinguishable from WT controls in body weight, fat and protein contents, and food consumption when they are allowed unlimited access to a standard rodent diet. We conclude that although CRY signaling may not be essential for the maintenance of energy homeostasis under steady-state nutritional conditions, Cry1 may play a role in readjusting energy balance under changing nutritional circumstances. These studies reinforce the important role of circadian clock genes in energy homeostasis and suggest that Cry1 is a plausible target for anti-obesity therapy.

Deep brain stimulation in treatment-resistant depression in mice: comparison with the CRF1 antagonist, SSR125543.

Deep brain stimulation (DBS) has been demonstrated to represent a targeted therapeutic alternative for treatment-resistant depression. In this study, we used the unpredictable chronic mild stress (UCMS) test to validate high-frequency electrical stimulation of the cingulate cortex (CC) as a possible treatment to improve behavioral symptoms associated with a depressive-like state in treatment-resistant mice. The effects of DBS were compared with those of the CRF(1) antagonist, SSR125543. Mice were subjected to UCMS, which consisted of the sequential and unpredictable application of mild stressors for a total of 8 weeks. From week 4 until the end of week 6, mice received either a saline injection or were treated with the antidepressant, fluoxetine (10 mg/kg, i.p.). At the end of week 6, fluoxetine-treated mice were subdivided into two populations, that is one responding to fluoxetine, and one not responding, based on their fur coat state, an index of depressive-like state in this test. Non-responders were subsequently subjected to bilateral DBS (at 80 or 120 Hz, 1-h/day) or were treated with SSR125543 (20 mg/kg, i.p.) for two weeks. Stimulation of the CC at 120 Hz in treatment-resistant mice resulted in a normalization of motivated-like responses, anxiety-related behaviors, hyperactivity and aggressiveness. SSR125543 improved motivated-like and aggressive behaviors. These findings demonstrate that bilateral DBS of the CC and, to a lesser extent, pharmacological blockade of the CRF(1) receptor in treatment-resistant mice can attenuate several aspects of depressive-like behaviors, suggesting further that these approaches may represent valid alternatives for the treatment of drug-resistant depressed and/or anxious patients.

Further evidence for the sleep-promoting effects of 5-HT2A receptor antagonists and demonstration of synergistic effects with the hypnotic, zolpidem in rats.

5-Hydroxytryptamine (5-HT)2A antagonists are promising therapeutic agents for the treatment of sleep maintenance insomnias, but unlike hypnotics, they have limited effects on sleep initiation. This study evaluated the effects of several 5-HT2A antagonists (eplivanserin, volinanserin and AVE8488) alone and/or in combination with the short-acting hypnotic, zolpidem, on the rat sleep profile. A repeated-measures design was used in which rats were treated with eplivanserin (3 and 10 mg/kg, i.p. or p.o.), volinanserin (0.3-3 mg/kg, i.p.), AVE8488 (0.1-3 mg/kg, i.p.) and zolpidem (3 and 10 mg/kg, p.o.). In addition, animals received a combination of eplivanserin (3 mg/kg, p.o.) and zolpidem (3 mg/kg, p.o.). Electroencephalogram was analyzed for 6 h after administration. Eplivanserin did not modify wakefulness and non-rapid eye movement sleep (NREMS), while zolpidem (10 mg/kg po) induced a marked increase in NREMS duration. Volinanserin (1 and 3 mg/kg) and AVE8488 (0.3 mg/kg) similarly increased NREMS, while reducing wakefulness. Moreover, the 5-HT2A antagonists and, to a lesser extent, zolpidem, increased duration of NREMS episodes, while decreasing their frequency. When eplivanserin was co-administered with zolpidem, a synergistic effect was observed as the combination produced an increase in NREMS time and bouts duration. These findings confirm further that 5-HT2A antagonists promote the maintenance of sleep, and suggest that combining a 5-HT2A antagonist with a short-acting hypnotic may be a useful strategy for the treatment of insomnia.

The vasopressin V(1b) receptor antagonist SSR149415 in the treatment of major depressive and generalized anxiety disorders: results from 4 randomized, double-blind, placebo-controlled studies.

OBJECTIVE: These studies were designed to evaluate the efficacy and tolerability of the first nonpeptide vasopressin V(1b) receptor antagonist, SSR149415, in the treatment of major depressive disorder (MDD) and generalized anxiety disorder (GAD). METHOD: Studies were randomized 8-week, double-blind, placebo-controlled trials evaluating 100- and 250-mg twice daily doses of SSR149415, placebo, and escitalopram 10 mg/day or paroxetine 20 mg/day, conducted from August 2006 through February 2008. Participants met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision criteria for MDD or GAD. Baseline Montgomery-Asberg Depression Rating Scale (MADRS) and Hamilton Depression Rating Scale (HDRS) total scores were ≥ 24 and 18, respectively, and in the GAD trial baseline Hamilton Anxiety Rating Scale (HARS) score was ≥ 22. Primary efficacy variables included changes from baseline in total score on HDRS or HARS and MADRS, and the secondary variable included changes in the Clinical Global Impressions-Severity of Illness score (CGI-S). A 4-week, double-blind, placebo-controlled study evaluating the effect of 100- and 250-mg twice daily doses of SSR149415 on the hypothalamic-pituitary-adrenal (HPA) axis in MDD patients was also conducted. RESULTS: In the GAD trial, SSR149415 did not separate from placebo on the primary (HARS-100 mg: P = .29; 250 mg: P = .21) and secondary (CGI-S-100 mg: P = .18; 250 mg: P = .24) outcome measures, while paroxetine demonstrated efficacy (HARS: P = .003; CGI-S: P = .01). In 2 MDD trials, SSR149415-treated patients did not show significant improvement from baseline on any outcome measure compared with placebo-treated patients (HDRS-100 mg: P = .21 and .48, respectively; 250 mg: P = .22 and P = .46, respectively; CGI-S-100 mg: P = .64 and P = .82, respectively; 250 mg: P = .33 and P = .08, respectively). In the third MDD study, SSR149415 250 mg (P = .04), but not escitalopram (P = .15), demonstrated significant improvement compared to placebo on the HDRS total score at week 8. SSR149415 had no deleterious effects on the HPA axis. CONCLUSIONS: These studies demonstrate that SSR149415 may not be useful for the treatment of GAD and that its antidepressant potential needs to be further evaluated. TRIAL REGISTRATION: ClinicalTrials.gov identifiers: NCT00374166 (Sanofi ID number: DFI5880), NCT00361491 (Sanofi ID number: DFI5879), NCT00358631 (Sanofi ID number: DFI5878), NCT01606384 (Sanofi ID number: PDY5467).

SAR110894, a potent histamine H3-receptor antagonist, displays procognitive effects in rodents.

SAR110894 is a novel histamine H3-R ligand, displaying high and selective affinity for human, rat or mouse H3-Rs. SAR110894 is a potent H3-R antagonist at native receptors, reversing R-α-methylhistamine-induced inhibition of electrical field stimulation contraction in the guinea-pig ileum. Additionally, SAR110894 inhibited constitutive GTPγS binding at human H3-Rs demonstrating inverse agonist properties. In behavioral models addressing certain aspects of cognitive impairment associated with schizophrenia (CIAS) and attention deficit/hyperactivity disorder (ADHD), SAR110894 improved memory performances in several variants of the object recognition task in mice (0.3-3 mg/kg, p.o.) or rats (0.3-1 mg/kg, p.o.). Moreover, SAR110894 (1 mg/kg, p.o.) reversed a deficit in working memory in the Y-maze test, following an acute low dose of phencyclidine (PCP) (0.5 mg/kg, i.p.) in mice sensitized by repeated treatment with a high dose of PCP (10 mg/kg, i.p.). In the latent inhibition (LI) model, SAR110894 potentiated LI in saline-treated rats (1 and 3 mg/kg, i.p.) and reversed abnormally persistent LI induced by neonatal nitric oxide synthase (NOS) inhibition in rodents (0.3-3 mg/kg, i.p.). In a social novelty discrimination task in rats, SAR110894 attenuated selective attention deficit induced by neonatal PCP treatment (3 and 10 mg/kg, p.o.) or a parametric modification of the procedure (3 and 10 mg/kg, p.o.). SAR110894 showed efficacy in several animal models related to the cognitive deficits in Alzheimer's disease (AD). It prevented the occurrence of episodic memory deficit induced by scopolamine in rats (0.01-10 mg/kg, p.o.) or by the central infusion of the toxic amyloid fragment ß25₋35 in the object recognition test in mice (1 and 3 mg/kg, p.o.). Altogether, these findings suggest that SAR110894 may be of therapeutic interest for the treatment of the cognitive symptoms of AD, schizophrenia and certain aspects of ADHD.

Awakening properties of newly discovered highly selective H3 receptor antagonists in rats.

The objective of the present study was to compare the awakening effects of two newly discovered H3 receptor antagonists (i.e. SAR110894 and SAR110068) with those of reference H3 receptor ligands (i.e. ciproxifan, ABT-0239 and GSK189254) and classical psychostimulants (i.e. amphetamine and modafinil) by using EEG recording in rats during their light phase. Results showed that SAR110068 (10 and 30 mg/kg, p.o.) increased wakefulness and decreased slow wave sleep to a similar degree than ciproxifan (10 mg/kg, i.p.), ABT-0239 (10 mg/kg, p.o.) and GSK189254 (10 mg/kg, p.o.), while SAR110894 (3-30 mg/kg, p.o.) did not modify significantly any of the sleep/wakefulness parameters. Time-course analysis revealed that the awakening effects of GSK189254 lasted for about 1h, while ciproxifan, ABT-0239 and SAR110068 produced such effects for 3-4 h. The magnitude of the awakening effects of the psychostimulants, amphetamine (3 mg/kg, i.p.) and modafinil (300 mg/kg, i.p.), was dramatically higher than with the H3 compounds, and they lasted for 5 and 6 h, respectively. However, unlike the H3 receptor antagonists, both psychostimulants produced a strong increase in theta (θ) rhythm, which is indicative of CNS side effects, such as hyperactivity or abnormal excitation. In conclusion, this study provides further evidence to support the potential use of H3 receptor antagonists in the treatment of vigilance and sleep-wake disorders such as narcolepsy.

Is there still a future for neurokinin 3 receptor antagonists as potential drugs for the treatment of psychiatric diseases?

Selective non-peptide antagonists for the neurokinin 3 (NK(3)) receptor first became available about twenty years ago. Although the understanding of the role of the NK(3) receptor in the brain has been greatly complicated by marked species differences in its distribution and by pharmacological heterogeneity, studies with brain-penetrant non-peptide NK(3) receptor antagonists in animals have indicated that these compounds may find utility in a number of psychiatric diseases, including schizophrenia, anxiety and depressive disorders. However, clinical studies with selective NK(3) receptor antagonists in these psychiatric conditions have been disappointing and they were unable to confirm the promising therapeutic potential from animal studies, thereby questioning the therapeutic utility of these compounds for CNS disorders. The purpose of this article is to provide a critical overview of the available data on NK(3) receptor antagonists in the psychiatry research and development field, by reviewing the behavioral and neurochemical effects of these agents in both preclinical and clinical studies.