Browsing by Author "Cerne, Rok"
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Item Catechol estrogens stimulate insulin secretion in pancreatic β-cells via activation of the transient receptor potential A1 (TRPA1) channel(American Society for Biochemistry and Molecular Biology, 2019-02-22) Ma, Wenzhen; Chen, Xingjuan; Cerne, Rok; Syed, Samreen K.; Ficorilli, James V.; Cabrera, Over; Obukhov, Alexander G.; Efanov, Alexander M.; Cellular and Integrative Physiology, School of MedicineEstrogen hormones play an important role in controlling glucose homeostasis and pancreatic β-cell function. Despite the significance of estrogen hormones for regulation of glucose metabolism, little is known about the roles of endogenous estrogen metabolites in modulating pancreatic β-cell function. In this study, we evaluated the effects of major natural estrogen metabolites, catechol estrogens, on insulin secretion in pancreatic β-cells. We show that catechol estrogens, hydroxylated at positions C2 and C4 of the steroid A ring, rapidly potentiated glucose-induced insulin secretion via a nongenomic mechanism. 2-Hydroxyestrone, the most abundant endogenous estrogen metabolite, was more efficacious in stimulating insulin secretion than any other tested catechol estrogens. In insulin-secreting cells, catechol estrogens produced rapid activation of calcium influx and elevation in cytosolic free calcium. Catechol estrogens also generated sustained elevations in cytosolic free calcium and evoked inward ion current in HEK293 cells expressing the transient receptor potential A1 (TRPA1) cation channel. Calcium influx and insulin secretion stimulated by estrogen metabolites were dependent on the TRPA1 activity and inhibited with the channel-specific pharmacological antagonists or the siRNA. Our results suggest the role of estrogen metabolism in a direct regulation of TRPA1 activity with potential implications for metabolic diseases.Item Electroacupuncture Alleviates Anxiety-like Behavior in Pain Aversion Rats by Attenuating the Expression of Neuropeptide Y in Anterior Cingulate Cortex(Elsevier, 2022) Shao, Fangbing; Du, Junying; Wang, Sisi; Cerne, Rok; Fang, Junfan; Shao, Xiaomei; Jin, Xiaoming; Fang, Jianqiao; Anatomy, Cell Biology and Physiology, School of MedicineBackground: Pain is considered as a multidimensional conscious experience that includes a sensory component and a negative affective-motivational component. Electroacupuncture (EA) is widely used to treat pain and pain-induced negative emotions, however, little is known about the mechanisms underlying the effect of EA. Objective: This study investigated the effect of EA on alleviating the anxiety-like behaviors in pain aversion rats and its anterior cingulate cortex (ACC) regulation mechanism. Methods: After a Freund's complete adjuvant (CFA)-conditioned place aversion (C-CPA) model was established in rats, EA treatment (2/100 Hz, 30 min, once/day, 4 days totally) was applied at bilateral Zusanli (ST36) and Kunlun (BL60) acupoints. Von Frey filaments were used to measure changes of pain withdrawal threshold (PWT) at indicated time points. Elevated zero maze (EZM) was used to investigate the changes of pain-related anxiety and CPA was used to investigate the changes of pain aversion. The protein expression levels of GAD67, PV, and NPY in ACC were detected by Western blotting. Results: Compared with the control group, the staying time in the "CFA-paired compartment" was significantly reduced, and the PWT was decreased in model group. In the EZM assessment, the distance and the time in open arm, as well as the number of open arm entries of model group were significantly lower than those in the control group. In the CPA assessment, the time spent in the "CFA-paired compartment" was significantly decreased in model group compared with control group, and EA reversed the changes in pain sensation and in pain-related emotions. Western blotting showed that the NPY level, but not the levels of GAD67 and PV, was significantly increased in the ACC of the model group compared to that of the control group. The increased expression of NPY in the ACC was significantly downregulated by EA, while sham EA produced no such effect. Conclusion: EA can effectively relieve the pain and pain-related emotions, and its mechanism may be achieved by down-regulating the expression of NPY in the ACC.Item GABAkines – Advances in the discovery, development, and commercialization of positive allosteric modulators of GABAA receptors(Elsevier, 2022-06) Cerne, Rok; Lippa, Arnold; Poe, Michael M.; Smith, Jodi L.; Jin, Xiaoming; Ping, Xingjie; Golani, Lalit K.; Cook, James M.; Witkin, Jeffrey M.; Anatomy and Cell Biology, School of MedicinePositive allosteric modulators of γ-aminobutyric acid-A (GABAA) receptors or GABAkines have been widely used medicines for over 70 years for anxiety, epilepsy, sleep, and other disorders. Traditional GABAkines like diazepam have safety and tolerability concerns that include sedation, motor-impairment, respiratory depression, tolerance and dependence. Multiple GABAkines have entered clinical development but the issue of side-effects has not been fully solved. The compounds that are presently being developed and commercialized include several neuroactive steroids (an allopregnanolone formulation (brexanolone), an allopregnanolone prodrug (LYT-300), Sage-324, zuranolone, and ganaxolone), the α2/3-preferring GABAkine, KRM-II-81, and the α2/3/5-preferring GABAkine PF-06372865 (darigabat). The neuroactive steroids are in clinical development for post-partum depression, intractable epilepsy, tremor, status epilepticus, and genetic epilepsy disorders. Darigabat is in development for epilepsy and anxiety. The imidazodiazepine, KRM-II-81 is efficacious in animal models for the treatment of epilepsy and post-traumatic epilepsy, acute and chronic pain, as well as anxiety and depression. The efficacy of KRM-II-81 in models of pharmacoresistant epilepsy, preventing the development of seizure sensitization, and in brain tissue of intractable epileptic patients bodes well for improved therapeutics. Medicinal chemistry efforts are also ongoing to identify novel and improved GABAkines. The data document gaps in our understanding of the molecular pharmacology of GABAkines that drive differential pharmacological profiles, but emphasize advancements in the ability to successfully utilize GABAA receptor potentiation for therapeutic gain in neurology and psychiatry.Item GABAkines – Advances in the Discovery, Development, and Commercialization of Positive Allosteric Modulators of GABAA Receptors(Elsevier, 2022) Cerne, Rok; Lippa, Arnold; Poe, Michael M.; Smith, Jodi L.; Jin, Xiaoming; Ping, Xingjie; Golani, Lalit K.; Cook, James M.; Witkin, Jeffrey M.; Anatomy, Cell Biology and Physiology, School of MedicinePositive allosteric modulators of γ-aminobutyric acid-A (GABAA) receptors or GABAkines have been widely used medicines for over 70 years for anxiety, epilepsy, sleep, and other disorders. Traditional GABAkines like diazepam have safety and tolerability concerns that include sedation, motor-impairment, respiratory depression, tolerance and dependence. Multiple GABAkines have entered clinical development but the issue of side-effects has not been fully solved. The present review focuses on the new GABAkines in. The compounds that are presently being developed and commercialized include several neuroactive steroids (an allopregnanolone formulation (brexanolone), an allopregnanolone prodrug (LYT-300), Sage-324, zuranolone, and ganaxolone), the α2/3-preferring GABAkine, KRM-II-81, and the α2/3/5-preferring GABAkine PF-06372865 (darigabat). The neuroactive steroids are in clinical development for post-partum depression, intractable epilepsy, tremor, status epilepticus, and genetic epilepsy disorders. Darigabat is in development for epilepsy and anxiety. The imidazodiazepine, KRM-II-81 is efficacious in animal models for the treatment of epilepsy and post-traumatic epilepsy, acute and chronic pain, as well as anxiety and depression. The efficacy of KRM-II-81 in models of pharmacoresistant epilepsy, preventing the development of seizure sensitization, and in brain tissue of intractable epileptic patients bodes well for improved therapeutics. Medicinal chemistry efforts are also ongoing to identify novel and improved GABAkines. The data document gaps in our understanding of the molecular pharmacology of GABAkines that drive differential pharmacological profiles, but emphasize advancements in the ability to successfully utilize GABAA receptor potentiation for therapeutic gain in neurology and psychiatry.Item Hydrochloride Salt of the GABAkine KRM-II-81(American Chemical Society, 2022-07-27) Mian, Md Yeunus; Divović, Branka; Sharmin, Dishary; Pandey, Kamal P.; Golani, Lalit K.; Tiruveedhula, V.V.N. Phani Babu; Cerne, Rok; Smith, Jodi L.; Ping, Xingjie; Jin, Xiaoming; Imler, Gregory H.; Deschamps, Jeffrey R.; Lippa, Arnold; Cook, James M.; Savić, Miroslav M.; Rowlett, James; Witkin, Jeffrey M.; Anatomy, Cell Biology and Physiology, School of MedicineImidazodiazepine (5-(8-ethynyl-6-(pyridin-2-yl)-4H-benzo[f]imidazole[1,5-α][1,4]diazepin-3-yl) oxazole or KRM-II-81) is a potentiator of GABAA receptors (a GABAkine) undergoing preparation for clinical development. KRM-II-81 is active against many seizure and pain models in rodents, where it exhibits improved pharmacological properties over standard-of-care agents. Since salts can be utilized to create opportunities for increased solubility, enhanced absorption, and distribution, as well as for efficient methods of bulk synthesis, a hydrochloride salt of KRM-II-81 was prepared. KRM-II-81·HCl was produced from the free base with anhydrous hydrochloric acid. The formation of the monohydrochloride salt was confirmed by X-ray crystallography, as well as 1H NMR and 13C NMR analyses. High water solubility and a lower partition coefficient (octanol/water) were exhibited by KRM-II-81·HCl as compared to the free base. Oral administration of either KRM-II-81·HCl or the free base resulted in high concentrations in the brain and plasma of rats. Oral dosing in mice significantly increased the latency to both clonic and tonic convulsions and decreased pentylenetetrazol-induced lethality. The increased water solubility of the HCl salt enables intravenous dosing and the potential for higher concentration formulations compared with the free base without impacting anticonvulsant potency. Thus, KRM-II-81·HCl adds an important new compound to facilitate the development of these imidazodiazepines for clinical evaluation.Item Imidazodiazepine Anticonvulsant, KRM-II-81, Produces Novel, Non-diazepam-like Antiseizure Effects(ACS, 2020-09) Knutson, Daniel E.; Smith, Jodi L.; Ping, Xingjie; Jin, Xiaoming; Golani, Lalit K.; Li, Guanguan; Tiruveedhula, Vera Venkata Naga Phani Babu; Rashid, Farjana; Mian, Md Yeunus; Jahan, Rajwana; Sharmin, Dishary; Cerne, Rok; Cook, James M.; Witkin, Jeffrey M.; Anatomy and Cell Biology, School of MedicineThe need for improved medications for the treatment of epilepsy and chronic pain is essential. Epileptic patients typically take multiple antiseizure drugs without complete seizure freedom, and chronic pain is not fully managed with current medications. A positive allosteric modulator (PAM) of α2/3-containing GABAA receptors (5-(8-ethynyl-6-(pyridin-2-yl)-4H-benzo[f]imidazole[1,5-α][1,4]diazepin-3-yl) oxazole or KRM-II-81 (8) is a lead compound in a series of imidazodiazepines. We previously reported that KRM-II-81 produces broad-based anticonvulsant and antinociceptive efficacy in rodent models and provides a wider margin over motoric side effects than that of other GABAA receptor PAMs. The present series of experiments was designed to fill key missing gaps in prior preclinical studies assessing whether KRM-II-81 could be further differentiated from nonselective GABAA receptor PAMs using the anticonvulsant diazepam (DZP) as a comparator. In multiple chemical seizure provocation models in mice, KRM-II-81 was either equally or more efficacious than DZP. Most strikingly, KRM-II-81 but not DZP blocked the development of seizure sensitivity to the chemoconvulsants cocaine and pentylenetetrazol in seizure kindling models. These and predecessor data have placed KRM-II-81 into consideration for clinical development requiring the manufacture of kilogram amounts of good manufacturing practice material. We describe here a novel synthetic route amenable to kilogram quantity production. The new biological and chemical data provide key steps forward in the development of KRM-II-81 (8) as an improved treatment option for patients suffering from epilepsy.Item N-Substituted-3-alkoxy-derivatives of dextromethorphan are functional NMDA receptor antagonists in vivo: Evidence from an NMDA-induced seizure model in rats(Elsevier, 2021) Witkin, Jeffrey M.; Cerne, Rok; Newman, Amy H.; Izenwasser, Sari; Smith, Jodi L.; Tortella, Frank C.; Neurological Surgery, School of MedicineInterest in developing NMDA receptor antagonists with reduced side-effects for neurological and psychiatric disorders has been re-energized by the recent introduction of esketamine into clinical practice for treatment-resistant depression. Structural analogs of dextromethorphan bind with low affinity to the NMDA receptor ion channel, have functional effects in vivo, and generally display a lower propensity for side-effects than that of ketamine and other higher affinity antagonists. As such, the aim of the present study was to determine whether a series of N-substituted-3-alkoxy-substituted dextromethorphan analogs produce their anticonvulsant effects through NMDA receptor blockade. Compounds were studied against NMDA-induced seizures in rats. Compounds were administered intracerebroventricularly in order to mitigate confounds of drug metabolism that arise from systemic administration. Comparison of the anticonvulsant potencies to their affinities for NMDA, σ1, and σ2 binding sites were made in order to evaluate the contribution of these receptors to anticonvulsant efficacy. The potencies to block convulsions were positively associated with their affinities to bind to the NMDA receptor ion channel ([3H]-TCP binding) (r = 0.71, p < 0.05) but not to σ1 receptors ([3H]-SKF 10047 binding) (r = -0.31, p = 0.46) or to σ2 receptors ([3H]-DTG binding) (p = -0.38, p = 0.36). This is the first report demonstrating that these dextromethorphan analogs are functional NMDA receptor antagonists in vivo. Given their potential therapeutic utility and favorable side-effect profiles, such low affinity NMDA receptor antagonists could be considered for further development in neurological (e.g., anticonvulsant) and psychiatric (e.g., antidepressant) disorders.Item The Positive Allosteric Modulator of α2/3-Containing GABAA Receptors, KRM-II-81, Is Active in Pharmaco-Resistant Models of Epilepsy and Reduces Hyperexcitability after Traumatic Brain Injury(American Society for Pharmacology and Experimental Therapeutics, 2020-01) Witkin, Jeffrey M.; Li, Guanguan; Golani, Lalit K.; Xiong, Wenhui; Smith, Jodi L.; Ping, Xingjie; Rashid, Farjana; Jahan, Rajwana; Cerne, Rok; Cook, James M.; Jin, Xiaoming; Neurological Surgery, School of MedicineThe imidizodiazepine, 5-(8-ethynyl-6-(pyridin-2-yl)-4H-benzo[f]imidazo[1,5-a][1,4]diazepin-3-yl)oxazole (KRM-II-81), is selective for α2/3-containing GABAA receptors. KRM-II-81 dampens seizure activity in rodent models with enhanced efficacy and reduced motor-impairment compared with diazepam. In the present study, KRM-II-81 was studied in assays designed to detect antiepileptics with improved chances of impacting pharmaco-resistant epilepsies. The potential for reducing neural hyperactivity weeks after traumatic brain injury was also studied. KRM-II-81 suppressed convulsions in corneal-kindled mice. Mice with kainate-induced mesial temporal lobe seizures exhibited spontaneous recurrent hippocampal paroxysmal discharges that were significantly reduced by KRM-II-81 (15 mg/kg, orally). KRM-II-81 also decreased convulsions in rats undergoing amygdala kindling in the presence of lamotrigine (lamotrigine-insensitive model) (ED50 = 19 mg/kg, i.p.). KRM-II-81 reduced focal and generalized seizures in a kainate-induced chronic epilepsy model in rats (20 mg/kg, i.p., three times per day). In mice with damage to the left cerebral cortex by controlled-cortical impact, enduring neuronal hyperactivity was dampened by KRM-II-81 (10 mg/kg, i.p.) as observed through in vivo two-photon imaging of layer II/III pyramidal neurons in GCaMP6-expressing transgenic mice. No notable side effects emerged up to doses of 300 mg/kg KRM-II-81. Molecular modeling studies were conducted: docking in the binding site of the α1β3γ2L GABAA receptor showed that replacing the C8 chlorine atom of alprazolam with the acetylene of KRM-II-81 led to loss of the key interaction with α1His102, providing a structural rationale for its low affinity for α1-containing GABAA receptors compared with benzodiazepines such as alprazolam. Overall, these findings predict that KRM-II-81 has improved therapeutic potential for epilepsy and post-traumatic epilepsy. SIGNIFICANCE STATEMENT: We describe the effects of a relatively new orally bioavailable small molecule in rodent models of pharmaco-resistant epilepsy and traumatic brain injury. KRM-II-81 is more potent and generally more efficacious than standard-of-care antiepileptics. In silico docking experiments begin to describe the structural basis for the relative lack of motor impairment induced by KRM-II-81. KRM-II-81 has unique structural and anticonvulsant effects, predicting its potential as an improved antiepileptic drug and novel therapy for post-traumatic epilepsy.Item (R)-(-)-Ketamine: The Promise of a Novel Treatment for Psychiatric and Neurological Disorders(MDPI, 2024-06-20) Shafique, Hana; Demers, Julie C.; Biesiada, Julia; Golani, Lalit K.; Cerne, Rok; Smith, Jodi L.; Szostak, Marta; Witkin, Jeffrey M.; Psychology, School of ScienceNMDA receptor antagonists have potential for therapeutics in neurological and psychiatric diseases, including neurodegenerative diseases, epilepsy, traumatic brain injury, substance abuse disorder (SUD), and major depressive disorder (MDD). (S)-ketamine was the first of a novel class of antidepressants, rapid-acting antidepressants, to be approved for medical use. The stereoisomer, (R)-ketamine (arketamine), is currently under development for treatment-resistant depression (TRD). The compound has demonstrated efficacy in multiple animal models. Two clinical studies disclosed efficacy in TRD and bipolar depression. A study by the drug sponsor recently failed to reach a priori clinical endpoints but post hoc analysis revealed efficacy. The clinical value of (R)-ketamine is supported by experimental data in humans and rodents, showing that it is less sedating, does not produce marked psychotomimetic or dissociative effects, has less abuse potential than (S)-ketamine, and produces efficacy in animal models of a range of neurological and psychiatric disorders. The mechanisms of action of the antidepressant effects of (R)-ketamine are hypothesized to be due to NMDA receptor antagonism and/or non-NMDA receptor mechanisms. We suggest that further clinical experimentation with (R)-ketamine will create novel and improved medicines for some of the neurological and psychiatric disorders that are underserved by current medications.