Journal of Pharmacology and Experimental Therapeutics最新文献

The neuropeptide S receptor (NPSR) has been identified as a potential therapeutic target for anxiety and post-traumatic stress disorder. Central administration of neuropeptide S (NPS) in male mice produces anxiolytic-like effects, hyperlocomotion, and memory enhancement. Currently, the literature is limited in the number of studies investigating the effects of NPS in female test subjects despite females facing a higher prevalence of anxiety-related pathology, as well as greater risk for adverse effects while taking psychoactive drugs. Moreover, no previous studies have considered the influence of estrous cycle on the effects of NPS. The present study investigates whether NPS-mediated behavioral phenotypes seen in males translate to females, and whether they are affected by estrous cycle stage. Female C57BL/6NCr mice were intracerebroventricularly cannulated and underwent behavioral paradigms to test locomotion, anxiety, and memory. Estrous cycle stage was determined through examination of vaginal cytology. Our results provide evidence that NPS-mediated behaviors are influenced by the estrous cycle. Administration of NPS decreased anxiety-like behaviors more robustly when the female mice were in high estrogen stages of the estrous cycle. Therefore, the desired anxiolytic-like effects of targeting the NPSR are intact in female mice. However, these effects may to be influenced by the stage of the estrous cycle. The NPSR remains a strong potential drug target for new anxiolytic compounds and based on our initial observations further studies exploring the interaction of estrous cycle and the NPS system are warranted. SIGNIFICANCE STATEMENT: The neuropeptide S (NPS) receptor has been identified as a potential target for treating anxiety, a condition that is most prevalent in females. Therefore, the potential interaction of estrous cycle with the NPS system described in the present study is an important first step in understanding the function of the NPS system in females.

Previous studies indicated differing effects of dopamine D₁-like and D₂-like receptor (D₁R and D₂R, respectively) agonists on cocaine self-administration. Leftward shifts by D₂R agonists in the cocaine self-administration dose-effect function contrast with decreases by D₁R agonists in maximal cocaine self-administration without rightward or leftward displacement. Whether the effects of the D₁R agonists are due to actions at D₁Rs has not been determined, possibly due to the difficulty in separating the blockade by a D₁R antagonist of the effects of the D₁R agonists and those of cocaine. In the present study, pretreatment with the D₁R agonists R(+)-SKF-81297 (0.1-1.0 mg/kg) and (±)-SKF-82958 (0.032-0.32 mg/kg) dose-dependently decreased maximal cocaine self-administration at doses below those affecting food-reinforced responding. In contrast, pretreatment with the D₂R agonists R(-)-NPA (0.001-0.01 mg/kg) and (-)-quinpirole (0.01-0.1 mg/kg) dose-dependently left-shifted the cocaine self-administration dose-effect function. The decreases by D₁R agonists in maximal cocaine self-administration were dose-dependently antagonized by the D₁R antagonist SCH-39166 at doses that alone had no effects on cocaine self-administration. Doses of SCH-39166 that blocked the effects of the D₁R agonists on cocaine self-administration were like those that shifted self-administration of D₁R agonists to the right but had no effects on self-administration of D₂R agonists. Self-administration of the D₂R agonists was dose-dependently shifted to the right by the preferential D₂R antagonist L-741,626 but not by SCH-39166. These results demonstrate that the decreases by the D₁R agonists in cocaine self-administration are selectively D₁R-mediated and support findings suggesting fundamentally distinct roles of the D₁Rs and D₂Rs in cocaine reinforcement. SIGNIFICANCE STATEMENT: Dopamine D₁-like (D₁R) agonists decrease maximal cocaine self-administration, whereas D₂-like (D₂R) agonists shift the cocaine self-administration dose-effect function leftward, with mechanisms for those different effects unclear. The present study demonstrates blockade by the selective D₁R antagonist SCH-39166 of D1R-mediated decreases in maximal cocaine self-administration at doses that blocked other D₁R-mediated effects but not effects of cocaine, suggesting fundamentally distinct roles of the dopamine D₁-like and D₂-like receptors in cocaine reinforcement and development of D₁R agonists as potential treatments for cocaine use disorder.

Discoidin domain receptor 1 (DDR1) is a collagen receptor with tyrosine kinase activity, and its expression is enhanced in various disease conditions. Although previous research suggests that DDR1 contributes to renal disease progression, DDR1 inhibitors for renal fibrosis have yet to be developed. In this study, we used unilateral ureteral obstruction (UUO) mice to investigate whether CH6824025, a strong and selective DDR1 phosphorylation inhibitor, can improve renal fibrosis. Furthermore, we performed 10x Visium spatial transcriptomics (ST) analysis on the kidney. CH6824025 suppressed the phosphorylation of DDR1 in the kidney, and the amount of hydroxyproline, the Sirius red- and the F4/80-positive area, and the mRNA expression of fibrosis and inflammation-related genes in the kidney were significantly decreased. 10x Visium ST analysis suggested that DDR1 is mainly expressed in distal nephrons under normal conditions but its expression appears to increase in the injured proximal tubules in UUO mice. Comparing mRNA expression in DDR1-positive spots in the Vehicle and the CH6824025 group, oxidative phosphorylation and mitochondrial dysfunction might be improved, and pathways involved in fibrosis tended to be inhibited in the CH6824025 administration group. Downstream analysis would suggest that mRNA expression changes in the CH6824025 group contribute to the inhibition of cell movement. Taken together, our findings suggest that CH6824025 inhibited kidney fibrosis in UUO mice, which might be due to the inhibition of the migration of inflammatory cells to the injury site and the reduction of inflammation. DDR1 inhibitors are expected to be a promising treatment of renal fibrosis. SIGNIFICANCE STATEMENT: The novel discoidin domain receptor 1 inhibitor CH6824025 could ameliorate fibrosis and inflammation in unilateral ureteral obstruction (UUO) mice. CH6824025 would inhibit cell motility (e.g., migration) that prevents the progression of fibrosis and improves mitochondrial function in UUO mice. CH6824025 could provide a significant benefit to patients with kidney fibrosis.

Cisplatin is a common platinum-based chemotherapeutic that induces acute kidney injury (AKI) in about 30% of patients. Pharmacokinetic/toxicodynamic (PKTD) models of cisplatin-induced AKI have been used to understand risk factors and evaluate potential mitigation strategies. While both traditional clinical biomarkers of kidney function [e.g., serum creatinine (SCr), blood urea nitrogen (BUN), estimated glomerular filtration rate (eGFR), and creatinine clearance (CrCl)] and newer subclinical biomarkers of kidney injury [e.g., urinary kidney injury molecule 1 (KIM-1), beta-2 microglobulin (B2M), neutrophil gelatinase-associated lipocalin (NGAL), calbindin, etc.] can be used to detect cisplatin-induced AKI, published PKTD models are limited to using only traditional clinical biomarkers. Previously identified risk factors for cisplatin nephrotoxicity have included dose, age, sex, race, body surface area, genetics, concomitant medications, and comorbid conditions. However, the relationships between concentrations and the pharmacokinetics (PK) of platinum and biomarkers of kidney injury have not been well elucidated. This review discusses the evaluation of cisplatin-induced nephrotoxicity in clinical studies, mouse models, and in vitro models, and examines the available human PK and toxicodynamic (TD) data. Improved understanding of the relationships between platinum PK and TD, in the presence of identified risk factors, will enable the prediction and prevention of cisplatin kidney injury. SIGNIFICANCE STATEMENT: As cisplatin treatment continues to cause AKI in a third of patients, it is critical to improve the understanding of the relationships between platinum PK and nephrotoxicity as assessed by traditional clinical and contemporary subclinical TD markers of kidney injury. Prediction and prevention of cisplatin-induced nephrotoxicity will be advanced by the evolving development of PKTD models that incorporate kidney injury biomarkers with enhanced sensitivity and include covariates that can impact risk of developing cisplatin-induced AKI.

Single nucleotide polymorphisms (SNPs) in cytochrome P450 (CYP450) enzymes alter the metabolism of a variety of drugs. Numerous medications, including chemotherapies, are metabolized by CYP450 enzymes, making the expression of this suite of enzymes in tumor cells relevant to prescription regimens for patients with cancer. We analyzed the characteristics of mutations of the cytochrome P450 2D6 (CYP2D6) enzymes in cancer patients obtained from the Catalogue of Somatic Mutations in Cancer (COSMIC), including mutation type, age of the patient, tissue type, and histology. Mutations were analyzed through the Cancer-Related Analysis of Variants Toolkit (CRAVAT) software along with cancer-specific high-throughput annotation of somatic mutations (CHASMplus) and variant effect scoring tool (VEST4) algorithms to determine the likelihood of being a driver and/or pathogenic mutation. For mutations with significant CHASMplus and VEST4 scores, structural analysis of each corresponding mutant protein was performed. The effect of each mutation was evaluated for its impact on the overall protein stability and ligand binding using Foldit Standalone and SwissDock, respectively. Structural analysis revealed that several missense mutations in CYP2D6 resulted in altered stability after energy minimization. Three missense mutations of CYP2D6 significantly altered docking stability, and those located on alpha helices near the docking site had a more significant impact than those not found in secondary protein structures. In conclusion, we have identified a series of mutations to CYP2D6 enzymes with possible relevance to cancer pathologies. SIGNIFICANCE STATEMENT: CYP2D6 is responsible for the metabolism of many anticancer drugs. This study identified and characterized a series of mutations in the CYP2D6 enzyme that occurred in tumors. We found it likely that many of these mutations would alter enzyme function, leading to changes in drug metabolism in the tumor. We provide a basis for predicting the likelihood of a patient carrying these mutations to identify patients who may benefit from a precision medicine approach to drug selection and dosing.

Amyloid β(Aβ) deposition and neurofibrillary tangles are widely considered the primary pathological hallmarks of familial and sporadic forms of Alzheimer disease (AD). However, cerebrovascular inflammation, which is prevalent in 70% of AD patients, is emerging as another core feature of AD pathology. In our current work, we investigated the hypothesis that Aβ42 exposure drives an increase in vascular cell adhesion molecule-1 (VCAM-1) expression, a cerebrovascular inflammatory marker expressed on the blood-brain barrier (BBB) endothelium in humans and murine models. We have demonstrated that the inflammation signaling pathway is upregulated in AD patient brains, and VCAM-1 expression is increased in AD patients compared with healthy controls. Furthermore, dynamic SPEC/CT imaging in APP,PS1 transgenic mice (a mouse model that overexpresses Aβ42) demonstrated VCAM-1 upregulation at the BBB. Although there is a strong association between Aβ42 exposure and an increase in VCAM-1 expression, the underlying mechanisms remain partially understood. Molecular mechanisms driving VCAM-1 expression at the BBB were investigated in polarized human cerebral microvascular endothelial cell monolayers. Moreover, by employing reverse-phase protein array assays and immunocytochemistry we demonstrated that Aβ42 increases VCAM-1 expression via the Src/p38/MEK signaling pathway. Therefore, targeting the Src/p38/MEK pathway may help modulate VCAM-1 expression at the BBB and help mitigate cerebrovascular inflammation in Alzheimer disease. SIGNIFICANCE STATEMENT: Although considered a core pathological feature of Alzheimer disease, molecular pathways leading to cerebrovascular inflammation remain only partially understood. Moreover, clinical diagnostic methods for detecting cerebrovascular inflammation are underdeveloped. This study demonstrated the detection of VCAM-1 using radio-iodinated VCAM-1 antibody and single-photon emission computed tomography/computed tomography imaging. Additionally, exposure to Aβ42 increases VCAM-1 expression on the blood-brain barrier endothelium via the Src/p38/MEK pathway. These findings are expected to aid in the development of diagnostic and therapeutic approaches for addressing cerebrovascular inflammation in AD.

MK-8189 is a novel phosphodiesterase 10A (PDE10A) inhibitor being evaluated in clinical studies for the treatment of schizophrenia. PDE10A is a cyclic nucleotide phosphodiesterase enzyme highly expressed in medium spiny neurons of the striatum. MK-8189 exhibits sub-nanomolar potency on the PDE10A enzyme and has excellent pharmaceutical properties. Oral administration of MK-8189 significantly increased cGMP and pGluR1 in rat striatal tissues. Activation of the dopamine D1 direct and D2 indirect pathways was demonstrated by detecting significant elevation of mRNA encoding substance P (Sub P) and enkephalin (ENK) after MK-8189 administration. The PDE10A tracer [³H]MK-8193 was used determine the PDE10A enzyme occupancy (EO) required for efficacy in behavioral models. In the rat conditioned avoidance responding assay, MK-8189 significantly decreased avoidance behavior at PDE10A EO greater than ~48%. MK-8189 significantly reversed an MK-801-induced deficit in pre-pulse inhibition at PDE10A EO of ~47% and higher. Target engagement of MK-8189 in rhesus monkeys was examined with [¹¹C]MK-8193 in PET studies and plasma concentrations of 127nM MK-8189 yielded ~50% EO in the striatum. The impact of MK-8189 on cognitive symptoms was evaluated using the objective retrieval task in rhesus monkeys. MK-8189 significantly attenuated a ketamine-induced deficit in object retrieval performance at exposure that yielded ~29% PDE10A EO. These findings demonstrate the robust impact of MK-8189 on striatal signaling and efficacy in preclinical models of symptoms associated with schizophrenia. Data from these studies were used to establish the relationship between preclinical efficacy, plasma exposures, and PDE10A EO to guide dose selection of MK-8189 in clinical studies. Significance Statement We describe the primary pharmacology of MK-8189 a PDE10A inhibitor under evaluation for the treatment of schizophrenia. We report efficacy in preclinical models that have been used to characterize other PDE10A inhibitors and atypical antipsychotics. The PDE10A occupancy achieved by MK-8189 in behavioral studies was used to support dose selection in clinical trials. This work provides evidence to support exploration of higher levels of PDE10A occupancy in clinical trials to determine if this translates to improved efficacy in patients.

Aneurysmal subarachnoid hemorrhage (aSAH) may be associated with cerebral vasospasm, which can lead to delayed cerebral ischemia, infarction, and worsened functional outcomes. The delayed nature of cerebral ischemia secondary to SAH-related vasculopathy presents a window of opportunity for the evaluation of well-tolerated neuroprotective agents administered soon after ictus. Secondary ischemic injury in SAH is associated with increased extracellular glutamate, which can overactivate NMDA receptors (NMDARs), thereby triggering NMDAR-mediated cellular damage. In this study, we have evaluated the effect of the pH-sensitive GluN2B-selective NMDAR inhibitor, NP10679, on neurologic impairment after SAH. This compound demonstrates a selective increase in potency at the acidic extracellular pH levels that occur in the setting of ischemia. We found that NP10679 produced durable improvement of behavioral deficits in a well-characterized murine model of SAH, and these effects were greater than those produced by nimodipine alone, the current standard of care. In addition, we observed an unexpected reduction in SAH-induced luminal narrowing of the middle cerebral artery. Neither nimodipine nor NP10679 alter each other's pharmacokinetic profile, suggesting no obvious drug-drug interactions. Based on allometric scaling of both toxicological and efficacy data, the therapeutic margin in man should be at least 2. These results further demonstrate the utility of pH-dependent neuroprotective agents and GluN2B-selective NMDAR inhibitors as potential therapeutic strategies for the treatment of aSAH. Significance Statement This report describes the properties and utility of the GluN2B-selective pH-sensitive NMDA receptor inhibitor, NP10679, in a well-characterized rodent model of subarachnoid hemorrhage. We show that the administration of NP10679 improves long-term neurological function following subarachnoid hemorrhage, and that in rats there are no drug-drug interactions between NP10679 and nimodipine, the standard of care for this indication.