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Sharma K, Sharma KK, Mahindra A, Sehra N, Bagra N, Aaghaz S, Parmar R, Rathod GK, Jain R. Design, synthesis, and applications of ring-functionalized histidines in peptide-based medicinal chemistry and drug discovery. Med Res Rev 2023. [PMID: 36710510 DOI: 10.1002/med.21936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 12/12/2022] [Accepted: 01/06/2023] [Indexed: 01/31/2023]
Abstract
Modified and synthetic α-amino acids are known to show diverse applications. Histidine, which possesses numerous applications when subjected to synthetic modifications, is one such amino acid. The utility of modified histidines varies widely from remarkable biological activities to catalysis, and from nanotechnology to polymer chemistry. This renders histidine residue an important place in scientific research. Histidine is a well-studied scaffold and constitutes the active site of various enzymes catalyzing important reactions in the biological systems. A rational modification in histidine structure with a distinctly developed protocol extensively changes its physical and chemical properties. The utilization of modified histidines in search of potent, target selective and proteostable scaffolds is vital in the development of bioactive peptides with enhanced drug-likeliness. This review is a compilation and analysis of reported side-chain ring modifications at histidine followed by applications of ring-modified histidines in the synthesis of various categories of bioactive peptides and peptidomimetics.
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Affiliation(s)
- Komal Sharma
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Nagar, Punjab, India
| | - Krishna K Sharma
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Nagar, Punjab, India
| | - Amit Mahindra
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Nagar, Punjab, India
| | - Naina Sehra
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Nagar, Punjab, India
| | - Nitin Bagra
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Nagar, Punjab, India
| | - Shams Aaghaz
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Nagar, Punjab, India
| | - Rajesh Parmar
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Nagar, Punjab, India
| | - Gajanan K Rathod
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Nagar, Punjab, India
| | - Rahul Jain
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Nagar, Punjab, India
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Trubacova R, Drastichova Z, Novotny J. Biochemical and physiological insights into TRH receptor-mediated signaling. Front Cell Dev Biol 2022; 10:981452. [PMID: 36147745 PMCID: PMC9485831 DOI: 10.3389/fcell.2022.981452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 08/16/2022] [Indexed: 11/13/2022] Open
Abstract
Thyrotropin-releasing hormone (TRH) is an important endocrine agent that regulates the function of cells in the anterior pituitary and the central and peripheral nervous systems. By controlling the synthesis and release of thyroid hormones, TRH affects many physiological functions, including energy homeostasis. This hormone exerts its effects through G protein-coupled TRH receptors, which signal primarily through Gq/11 but may also utilize other G protein classes under certain conditions. Because of the potential therapeutic benefit, considerable attention has been devoted to the synthesis of new TRH analogs that may have some advantageous properties compared with TRH. In this context, it may be interesting to consider the phenomenon of biased agonism and signaling at the TRH receptor. This possibility is supported by some recent findings. Although knowledge about the mechanisms of TRH receptor-mediated signaling has increased steadily over the past decades, there are still many unanswered questions, particularly about the molecular details of post-receptor signaling. In this review, we summarize what has been learned to date about TRH receptor-mediated signaling, including some previously undiscussed information, and point to future directions in TRH research that may offer new insights into the molecular mechanisms of TRH receptor-triggered actions and possible ways to modulate TRH receptor-mediated signaling.
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Menthol exerts TRPM8-independent antiepileptic effects in prefrontal cortex pyramidal neurons. Brain Res 2022; 1783:147847. [DOI: 10.1016/j.brainres.2022.147847] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 02/03/2022] [Accepted: 02/23/2022] [Indexed: 11/22/2022]
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Wang Y, Yuan J, Yu X, Liu X, Tan C, Chen Y, Xu T. Vezatin regulates seizures by controlling AMPAR-mediated synaptic activity. Cell Death Dis 2021; 12:936. [PMID: 34642320 PMCID: PMC8511046 DOI: 10.1038/s41419-021-04233-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 09/20/2021] [Accepted: 09/28/2021] [Indexed: 01/03/2023]
Abstract
Although many studies have explored the mechanism of epilepsy, it remains unclear and deserves further investigation. Vezatin has been reported to be a synaptic regulatory protein involved in regulating neuronal synaptic transmission (NST). However, the role of vezatin in epilepsy remains unknown. Therefore, the aims of this study are to investigate the underlying roles of vezatin in epilepsy. In this study, vezatin expression was increased in hippocampal tissues from pilocarpine (PILO)-induced epileptic mice and a Mg2+-free medium-induced in vitro seizure-like model. Vezatin knockdown suppressed seizure activity in PILO-induced epileptic mice. Mechanistically, vezatin knockdown suppressed AMPAR-mediated synaptic events in epileptic mice and downregulated the surface expression of the AMPAR GluA1 subunit (GluA1). Interestingly, vezatin knockdown decreased the phosphorylation of GluA1 at serine 845 and reduced protein kinase A (PKA) phosphorylation; when PKA phosphorylation was suppressed by H-89 (a selective inhibitor of PKA phosphorylation) in vitro, the effects of vezatin knockdown on reducing the phosphorylation of GluA1 at serine 845 and the surface expression of GluA1 were blocked. Finally, we investigated the pattern of vezatin in brain tissues from patients with temporal lobe epilepsy (TLE), and we found that vezatin expression was also increased in patients with TLE. In summary, the vezatin expression pattern is abnormal in individuals with epilepsy, and vezatin regulates seizure activity by affecting AMPAR-mediated NST and the surface expression of GluA1, which is involved in PKA-mediated phosphorylation of GluA1 at serine 845, indicating that vezatin-mediated regulation of epileptic seizures represents a novel target for epilepsy.
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Affiliation(s)
- You Wang
- Department of Neurology, the Second Affiliated Hospital of Chongqing Medical University, 400010, Chongqing, China
| | - Jinxian Yuan
- Department of Neurology, the Second Affiliated Hospital of Chongqing Medical University, 400010, Chongqing, China
| | - Xinyuan Yu
- Department of Neurology, Chongqing Hospital of Traditional Chinese Medicine, 400021, Chongqing, China
| | - Xi Liu
- Department of Neurology, the Second Affiliated Hospital of Chongqing Medical University, 400010, Chongqing, China
| | - Changhong Tan
- Department of Neurology, the Second Affiliated Hospital of Chongqing Medical University, 400010, Chongqing, China
| | - Yangmei Chen
- Department of Neurology, the Second Affiliated Hospital of Chongqing Medical University, 400010, Chongqing, China
| | - Tao Xu
- Department of Neurology, the Second Affiliated Hospital of Chongqing Medical University, 400010, Chongqing, China.
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Identification of microRNA-target genes in mice hippocampus at 1 week after pilocarpine-induced status epilepticus. Biochem Biophys Res Commun 2020; 531:275-281. [DOI: 10.1016/j.bbrc.2020.06.125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 06/24/2020] [Indexed: 02/06/2023]
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Therapeutic potential of pharmacological agents targeting TRP channels in CNS disorders. Pharmacol Res 2020; 159:105026. [PMID: 32562815 DOI: 10.1016/j.phrs.2020.105026] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 05/21/2020] [Accepted: 06/11/2020] [Indexed: 02/07/2023]
Abstract
Central nervous system (CNS) disorders like Alzheimer's disease (AD), Parkinson disease (PD), stroke, epilepsy, depression, and bipolar disorder have a high impact on both medical and social problems due to the surge in their prevalence. All of these neuronal disorders share some common etiologies including disruption of Ca2+ homeostasis and accumulation of misfolded proteins. These misfolded proteins further disrupt the intracellular Ca2+ homeostasis by disrupting the activity of several ion channels including transient receptor potential (TRP) channels. TRP channel families include non-selective Ca2+ permeable channels, which act as cellular sensors activated by various physio-chemical stimuli, exogenous, and endogenous ligands responsible for maintaining the intracellular Ca2+ homeostasis. TRP channels are abundantly expressed in the neuronal cells and disturbance in their activity leads to various neuronal diseases. Under the pathological conditions when the activity of TRP channels is perturbed, there is a disruption of the neuronal homeostasis through increased inflammatory response, generation of reactive oxygen species, and mitochondrial dysfunction. Therefore, there is a potential of pharmacological interventions targeting TRP channels in CNS disorders. This review focuses on the role of TRP channels in neurological diseases; also, we have highlighted the current insights into the pharmacological modulators targeting TRP channels.
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Charli JL, Rodríguez-Rodríguez A, Hernández-Ortega K, Cote-Vélez A, Uribe RM, Jaimes-Hoy L, Joseph-Bravo P. The Thyrotropin-Releasing Hormone-Degrading Ectoenzyme, a Therapeutic Target? Front Pharmacol 2020; 11:640. [PMID: 32457627 PMCID: PMC7225337 DOI: 10.3389/fphar.2020.00640] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 04/21/2020] [Indexed: 12/17/2022] Open
Abstract
Thyrotropin releasing hormone (TRH: Glp-His-Pro-NH2) is a peptide mainly produced by brain neurons. In mammals, hypophysiotropic TRH neurons of the paraventricular nucleus of the hypothalamus integrate metabolic information and drive the secretion of thyrotropin from the anterior pituitary, and thus the activity of the thyroid axis. Other hypothalamic or extrahypothalamic TRH neurons have less understood functions although pharmacological studies have shown that TRH has multiple central effects, such as promoting arousal, anorexia and anxiolysis, as well as controlling gastric, cardiac and respiratory autonomic functions. Two G-protein-coupled TRH receptors (TRH-R1 and TRH-R2) transduce TRH effects in some mammals although humans lack TRH-R2. TRH effects are of short duration, in part because the peptide is hydrolyzed in blood and extracellular space by a M1 family metallopeptidase, the TRH-degrading ectoenzyme (TRH-DE), also called pyroglutamyl peptidase II. TRH-DE is enriched in various brain regions but is also expressed in peripheral tissues including the anterior pituitary and the liver, which secretes a soluble form into blood. Among the M1 metallopeptidases, TRH-DE is the only member with a very narrow specificity; its best characterized biological substrate is TRH, making it a target for the specific manipulation of TRH activity. Two other substrates of TRH-DE, Glp-Phe-Pro-NH2 and Glp-Tyr-Pro-NH2, are also present in many tissues. Analogs of TRH resistant to hydrolysis by TRH-DE have prolonged central efficiency. Structure-activity studies allowed the identification of residues critical for activity and specificity. Research with specific inhibitors has confirmed that TRH-DE controls TRH actions. TRH-DE expression by β2-tanycytes of the median eminence of the hypothalamus allows the control of TRH flux into the hypothalamus-pituitary portal vessels and may regulate serum thyrotropin secretion. In this review we describe the critical evidences that suggest that modification of TRH-DE activity in tanycytes, and/or in other brain regions, may generate beneficial consequences in some central and metabolic disorders and identify potential drawbacks and missing information needed to test these hypotheses.
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Affiliation(s)
- Jean-Louis Charli
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
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Pasierski M, Szulczyk B. Capsaicin inhibits sodium currents and epileptiform activity in prefrontal cortex pyramidal neurons. Neurochem Int 2020; 135:104709. [PMID: 32105721 DOI: 10.1016/j.neuint.2020.104709] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/31/2020] [Accepted: 02/20/2020] [Indexed: 11/19/2022]
Abstract
Capsaicin, a compound found in chili peppers, causes burning sensations by acting on the peripheral sensory system. However, it has also been reported to exert substantial effects on central neurons. The aim of this patch-clamp study was to test the antiepileptic potential of capsaicin in prefrontal cortical pyramidal neurons. Capsaicin at a concentration of 60 μM inhibited neuronal excitability. Moreover, later spikes in response to 50-s-long current steps were much smaller in amplitude in the presence of 60 μM capsaicin than in control solution. The tested compound did not influence the membrane potential. Voltage-clamp recordings showed that capsaicin markedly enhanced the use-dependent block of sodium channels (sodium currents were evoked at frequencies of 0,5 Hz and 10 Hz). The presence of the compound shifted the steady-state inactivation curve of sodium channels towards hyperpolarization, which suggests greater inactivation of sodium channels at rest in the presence of capsaicin. Moreover, capsaicin inhibited epileptiform events evoked in three different proepileptic solutions. Capsaicin abolished interictal-like events lasting less than 1 s recorded in zero magnesium solution with an increased potassium ion concentration. The drug also abolished long ictal events evoked in zero magnesium solution containing 4-AP. Moreover, ictal events recorded in zero magnesium solution containing picrotoxin were substantially shortened in the presence of capsaicin. We suggest that capsaicin exerts an antiepileptic effect. The important mechanism behind this phenomenon seems to be the inhibition of sodium channels, which is an effect of many antiepileptic drugs.
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Affiliation(s)
- Michał Pasierski
- Department of Pharmacodynamics, The Medical University of Warsaw, Warsaw, Banacha 1B, 02-097, Poland
| | - Bartłomiej Szulczyk
- Department of Pharmacodynamics, The Medical University of Warsaw, Warsaw, Banacha 1B, 02-097, Poland.
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Jorwal P, Sikdar SK. Lactate reduces epileptiform activity through HCA1 and GIRK channel activation in rat subicular neurons in an in vitro model. Epilepsia 2019; 60:2370-2385. [DOI: 10.1111/epi.16389] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 10/24/2019] [Accepted: 10/24/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Pooja Jorwal
- Molecular Biophysics Unit Indian Institute of Science Bangalore India
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ZDHHC8 critically regulates seizure susceptibility in epilepsy. Cell Death Dis 2018; 9:795. [PMID: 30038264 PMCID: PMC6056564 DOI: 10.1038/s41419-018-0842-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 06/07/2018] [Accepted: 06/25/2018] [Indexed: 12/17/2022]
Abstract
Epilepsy is one of the most prevalent and drug-refractory neurological disorders. Zinc finger DHHC-type containing 8 (ZDHHC8) is a putative palmitoyltransferase that is highly expressed in the brain. However, the impact of ZDHHC8 on seizures remains unclear. We aimed to explore the association of ZDHHC8 with epilepsy and investigate its in epileptogenesis in in vivo and in vitro models through behavioral, electrophysiological, and pathological studies. We used kainic acid- and pilocarpine-induced C57BL/6 mice and magnesium-free-induced pyramidal neurons as experimental epileptic models in this study. We first found increased ZDHHC8 expression in the brains of temporal lobe epilepsy (TLE) patients, similar to that observed in chronic epileptic mice, strongly suggesting that ZDHHC8 is correlated with human epilepsy. In the in vitro seizure models, knocking down ZDHHC8 using recombinant adeno-associated virus (rAAV) delayed seizure precipitation and decreased chronic spontaneous recurrent seizures (SRSs) and epileptiform-like discharges, while ZDHHC8 overexpression had the opposite effect. ZDHHC8 levels were consistent with seizure susceptibility in induced mice with SRSs. In an in vitro magnesium-free model, neuronal hyperexcitability and hypersynchrony were reduced in ZDHHC8-knockdown neurons but were increased in ZDHHC8-overexpressing neurons. To further explore the potential mechanisms, we observed that ZDHHC8 had a significant modulatory effect on 2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl) propanoic acid (AMPA) receptor-related excitatory, but not inhibitory, glutamatergic synaptic neurotransmission, further affecting the inward rectification of AMPA currents in acute hippocampal slices in whole-cell recordings. ZDHHC8 facilitated GluA1 trafficking to the neuronal surface in the hippocampus, as shown by immunoprecipitation and Western blotting. These results suggest that ZDHHC8 may promote the generation and propagation of seizures in humans and that knocking down ZDHHC8 might produce anti-epileptogenic effects in drug-resistant epilepsy. Our study provides evidence that may facilitate the development of an alternative approach for the treatment of epilepsy by modulating AMPA/GluA1-mediated neurotransmission.
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Yang Q, Hu YD, Wang XF, Zheng FS. Dl-3n-butylphthalide reduces epileptiform activity through GluA2-lacking calcium-permeable AMPARs in epilepsy models. Oncotarget 2017; 8:98242-98257. [PMID: 29228686 PMCID: PMC5716726 DOI: 10.18632/oncotarget.21529] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 09/21/2017] [Indexed: 11/25/2022] Open
Abstract
Epilepsy is the most prevalent chronic neurological disorder, and its pathological mechanism indicates that an imbalance between excitatory and inhibitory neurotransmission leads to neuronal hyperexcitability. Previous studies have suggested that dl-3n-butylphthalide (NBP) regulates the excitatory neurotransmitter glutamate in the brains of epileptic mice, however, the mechanisms are unknown. We investigated behavioral and electrophysiological factors in rats using NBP. In an in vivo pentylenetetrazole (PTZ)-induced epileptic seizure animal model, NBP decreased the generalized tonic-clonic seizure (GTCS) severity. In an acute hippocampal slice 4-aminopyridine (4-AP) epilepsy model in vitro, NBP decreased the epileptiform activity and miniature excitatory postsynaptic current (mEPSC) amplitude; there was no change in the miniature inhibitory postsynaptic current (mIPSC) amplitude or frequency. This effect suggested changes in excitatory synaptic transmission, which was altered through postsynaptic GluA2-lacking calcium-permeable AMPA receptors (CP-AMPARs). These findings showed that NBP suppressed epileptiform activity in these epilepsy models and provided the first detailed electrophysiological analysis of the impact of NBP in epilepsy models, which may be employed in future experimental or clinical therapies for patients with epilepsy.
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Affiliation(s)
- Qin Yang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Yi-Da Hu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Xue-Feng Wang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China.,Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing, 100101, China
| | - Fang-Shuo Zheng
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
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Effect of L-pGlu-(1-benzyl)-l-His-l-Pro-NH 2 against in-vitro and in-vivo models of cerebral ischemia and associated neurological disorders. Biomed Pharmacother 2016; 84:1256-1265. [PMID: 27810782 DOI: 10.1016/j.biopha.2016.10.059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Revised: 10/17/2016] [Accepted: 10/17/2016] [Indexed: 01/28/2023] Open
Abstract
Central nervous system plays a vital role in regulation of most of biological functions which are abnormally affected in various disorders including cerebral ischemia, Alzheimer's and Parkinson's (AD and PD) worldwide. Cerebral stroke is an extremely fatal and one of the least comprehensible neurological disorders due to limited availability of prospective clinical approaches and therapeutics. Since, some endogenous peptides like thyrotropin-releasing hormone have shown substantial neuroprotective potential, hence present study evaluates the newer thyrotropin-releasing hormone (TRH) analogue L-pGlu-(1-benzyl)-l-His-l-Pro-NH2 for its neuroprotective effects against oxygen glucose deprivation (OGD), glutamate and H2O2 induced injury in pheochromocytoma cell lines (PC-12 cells) and in-vivo ischemic injury in mice. Additionally, the treatment was further analyzed with respect to models of AD and PD in mice. Cerebral ischemia was induced by clamping both bilateral common carotid arteries for ten minutes. Treatment was administered to the mice five minute after restoration of blood supply to brain. Consequential changes in neurobehavioural, biochemical and histological parameters were assessed after a week. L-pGlu-(1-benzyl)-l-His-l-Pro-NH2 showed significant reduction in glutamate, H2O2 and OGD -induced cell death in concentration and time dependent manner. Moreover, L-pGlu-(1-benzyl)-l-His-l-Pro-NH2 resulted in a substantial reduction in CA1 (Cornus Ammonis 1) hippocampal neuronal cell death, inflammatory cytokines, TNF-α, IL-6 and oxidative stress in hippocampus. In addition, L-pGlu-(1-benzyl)-l-His-l-Pro-NH2 was found to be protective in two acute models of AD and PD as well these findings demonstrate the neuroprotective potential of L-pGlu-(1-benzyl)-l-His-l-Pro-NH2 in cerebral ischemia and other diseases, which may be mediated through reduction of excitotoxicity, oxidative stress and inflammation.
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Meena CL, Thakur A, Nandekar PP, Sangamwar AT, Sharma SS, Jain R. Synthesis of CNS active thyrotropin-releasing hormone (TRH)-like peptides: Biological evaluation and effect on cognitive impairment induced by cerebral ischemia in mice. Bioorg Med Chem 2015. [DOI: 10.1016/j.bmc.2015.07.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Meena CL, Ingole S, Rajpoot S, Thakur A, Nandeker PP, Sangamwar AT, Sharma SS, Jain R. Discovery of a low affinity thyrotropin-releasing hormone (TRH)-like peptide that exhibits potent inhibition of scopolamine-induced memory impairment in mice. RSC Adv 2015; 5:56872-56884. [PMID: 26191403 PMCID: PMC4501038 DOI: 10.1039/c5ra06935a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
TRH-like peptides were synthesized in which the critical N-terminus residue L-pGlu was replaced with various heteroaromatic rings, and the central residue histidine with 1-alkyl-L-histidines. All synthesized TRH-like peptides were evaluated in vitro as agonists in HEK mTRH-R1 and HEK mTRH-R2 cell lines, an expressing receptor binding assay (IC50), and cell signaling assay (EC50). The analeptic potential of the synthesized peptides was evaluated in vivo by using the antagonism of a pentobarbital-induced sleeping time. The peptides 6a, 6c and 6e were found to activate TRH-R2 with potencies (EC50) of 0.002 μM, 0.28 μM and 0.049 μM, respectively. In contrast, for signaling activation of TRH-R1, the same peptides required higher concentration of 0.414 μM, 50 μM and 19.1 μM, respectively in the FLIPR assay. The results showed that these peptides were 207, 178 and 389-fold selective towards TRH-R2 receptor subtype. In the antagonism of a pentobarbital-induced sleeping time assay, peptide 6c showed a 58.5% reduction in sleeping time. The peptide 6c exhibited high stability in rat blood plasma, a superior effect on the scopolamine-induced cognition impairment mice model, safe effects on the cardiovascular system, and general behavior using a functional observation battery (FOB).
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Affiliation(s)
- Chhuttan L. Meena
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, 160 062, Punjab, India
| | - Shubdha Ingole
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, 160 062, Punjab, India
| | - Satyendra Rajpoot
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, 160 062, Punjab, India
| | - Avinash Thakur
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, 160 062, Punjab, India
| | - Prajwal P. Nandeker
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, 160 062, Punjab, India
| | - Abhay T. Sangamwar
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, 160 062, Punjab, India
| | - Shyam S. Sharma
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, 160 062, Punjab, India
| | - Rahul Jain
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, 160 062, Punjab, India
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Wozniak DR, Quinnell TG. Unmet needs of patients with narcolepsy: perspectives on emerging treatment options. Nat Sci Sleep 2015; 7:51-61. [PMID: 26045680 PMCID: PMC4447169 DOI: 10.2147/nss.s56077] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The treatment options currently available for narcolepsy are often unsatisfactory due to suboptimal efficacy, troublesome side effects, development of drug tolerance, and inconvenience. Our understanding of the neurobiology of narcolepsy has greatly improved over the last decade. This knowledge has not yet translated into additional therapeutic options for patients, but progress is being made. Some compounds, such as histaminergic H3 receptor antagonists, may prove useful in symptom control of narcolepsy. The prospect of finding a cure still seems distant, but hypocretin replacement therapy offers some promise. In this narrative review, we describe these developments and others which may yield more effective narcolepsy treatments in the future.
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Affiliation(s)
- Dariusz R Wozniak
- Respiratory Support and Sleep Centre, Papworth Hospital, Cambridge, UK
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Diabetic-induced increased sodium channel activity attenuated by tetracaine in sensory neurons in vitro. Biochem Biophys Res Commun 2014; 453:296-301. [DOI: 10.1016/j.bbrc.2014.09.035] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 09/09/2014] [Indexed: 11/22/2022]
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Sah N, Sikdar SK. Tonic current through GABAA receptors and hyperpolarization-activated cyclic nucleotide-gated channels modulate resonance properties of rat subicular pyramidal neurons. Eur J Neurosci 2014; 40:2241-54. [PMID: 24720274 DOI: 10.1111/ejn.12581] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 02/10/2014] [Accepted: 03/05/2014] [Indexed: 11/26/2022]
Abstract
The subiculum, considered to be the output structure of the hippocampus, modulates information flow from the hippocampus to various cortical and sub-cortical areas such as the nucleus accumbens, lateral septal region, thalamus, nucleus gelatinosus, medial nucleus and mammillary nuclei. Tonic inhibitory current plays an important role in neuronal physiology and pathophysiology by modulating the electrophysiological properties of neurons. While the alterations of various electrical properties due to tonic inhibition have been studied in neurons from different regions, its influence on intrinsic subthreshold resonance in pyramidal excitatory neurons expressing hyperpolarization-activated cyclic nucleotide-gated (HCN) channels is not known. Using pharmacological agents, we show the involvement of α5βγ GABAA receptors in the picrotoxin-sensitive tonic current in subicular pyramidal neurons. We further investigated the contribution of tonic conductance in regulating subthreshold electrophysiological properties using current clamp and dynamic clamp experiments. We demonstrate that tonic GABAergic inhibition can actively modulate subthreshold properties, including resonance due to HCN channels, which can potentially alter the response dynamics of subicular pyramidal neurons in an oscillating neuronal network.
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Affiliation(s)
- Nirnath Sah
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560 012, India
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Beck P, Urbano FJ, Williams DK, Garcia-Rill E. Effects of leptin on pedunculopontine nucleus (PPN) neurons. J Neural Transm (Vienna) 2013; 120:1027-38. [PMID: 23263542 PMCID: PMC3618992 DOI: 10.1007/s00702-012-0957-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 12/10/2012] [Indexed: 12/24/2022]
Abstract
Leptin, a hormone that regulates appetite and energy expenditure, is increased in obese individuals, although these individuals often exhibit leptin resistance. Obesity is characterized by sleep/wake disturbances, such as excessive daytime sleepiness, increased REM sleep, increased nighttime arousals, and decreased percentage of total sleep time. Several studies have shown that short sleep duration is highly correlated with decreased leptin levels in both animal and human models. Arousal and rapid eye movement (REM) sleep are regulated by the cholinergic arm of the reticular activating system, the pedunculopontine nucleus (PPN). The goal of this project was to determine the role of leptin in the PPN, and thus in obesity-related sleep disorders. Whole-cell patch-clamp recordings were conducted on PPN neurons in 9- to 17-day-old rat brainstem slices. Leptin decreased action potential (AP) amplitude, AP frequency, and h-current (I(H)). These findings suggest that leptin causes a blockade of Na⁺ channels. Therefore, we conducted an experiment to test the effects of leptin on Na⁺ conductance. To determine the average voltage dependence of this conductance, results from each cell were equally weighted by expressing conductance as a fraction of the maximum conductance in each cell. I Na amplitude was decreased in a dose-dependent manner, suggesting a direct effect of leptin on these channels. The average decrease in Na⁺ conductance by leptin was ~40 %. We hypothesize that leptin normally decreases activity in the PPN by reducing I(H) and I(Na) currents, and that in states of leptin dysregulation (i.e., leptin resistance) this effect may be blunted, therefore causing increased arousal and REM sleep drive, and ultimately leading to sleep-related disorders.
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Affiliation(s)
- Paige Beck
- Center for Translational Neuroscience, Dept. Neurobiology & Dev. Sci., University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | | | - D. Keith Williams
- Center for Translational Neuroscience, Dept. Neurobiology & Dev. Sci., University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Edgar Garcia-Rill
- Center for Translational Neuroscience, Dept. Neurobiology & Dev. Sci., University of Arkansas for Medical Sciences, Little Rock, AR, USA
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Sah N, Sikdar SK. Transition in subicular burst firing neurons from epileptiform activity to suppressed state by feedforward inhibition. Eur J Neurosci 2013; 38:2542-56. [DOI: 10.1111/ejn.12262] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 04/21/2013] [Accepted: 04/23/2013] [Indexed: 01/03/2023]
Affiliation(s)
- Nirnath Sah
- Molecular Biophysics Unit; Indian Institute of Science; Bangalore; India
| | - Sujit K. Sikdar
- Molecular Biophysics Unit; Indian Institute of Science; Bangalore; India
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Singh JN, Jain G, Sharma SS. In vitro hyperglycemia enhances sodium currents in dorsal root ganglion neurons: an effect attenuated by carbamazepine. Neuroscience 2012; 232:64-73. [PMID: 23262239 DOI: 10.1016/j.neuroscience.2012.12.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 12/06/2012] [Accepted: 12/07/2012] [Indexed: 12/13/2022]
Abstract
Neuropathy is often seen in uncontrolled diabetes and the mechanisms involved for neuropathic pain are poorly understood. Hyperglycemia is a consequence of chronic uncontrolled diabetes and it is postulated to produce neuropathic pain. Therefore, in this study, we have investigated the effects of hyperglycemia on Na(+) channel kinetics in cultured dorsal root ganglion (DRG) neurons from neonatal rats using whole-cell patch-clamp technique. Hyperglycemia-induced increase in density of tetrodotoxin resistant (TTXr) Na(+) currents was increased in time- and concentration-dependent manner. The increase was maximal with 60 mM and 24 h. There was no change Na(+) current density in time-matched control neurons. The conductance curve of TTXr Na(+) current shifted leftward after 24 h exposure to 45 mM glucose. Carbamazepine (CBZ, 100 μM) depressed TTXr Na(+) current in neurons incubated with control (17.26), 45 and 60 mM of glucose. The depression observed with CBZ in the presence of high glucose, i.e., 45 mM (86.5±4.9%) was significantly greater than control (61.6±1.8%). Hyperglycemia also increased reactive oxygen species (ROS) activity and was attenuated by CBZ. These results suggest that short-term exposure of DRG neurons to high glucose concentrations enhance the Na(+) channel activity, and were attenuated by CBZ via ROS-dependent mechanisms.
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Affiliation(s)
- J N Singh
- Electrophysiology Laboratory, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER)(1), S. A. S. Nagar (Mohali) 160 062, Punjab, India.
| | - G Jain
- Electrophysiology Laboratory, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER)(1), S. A. S. Nagar (Mohali) 160 062, Punjab, India
| | - S S Sharma
- Electrophysiology Laboratory, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER)(1), S. A. S. Nagar (Mohali) 160 062, Punjab, India
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Khomane KS, Nandekar PP, Wahlang B, Bagul P, Shaikh N, Pawar YB, Meena CL, Sangamwar AT, Jain R, Tikoo K, Bansal AK. Mechanistic Insights into PEPT1-Mediated Transport of a Novel Antiepileptic, NP-647. Mol Pharm 2012; 9:2458-68. [DOI: 10.1021/mp200672d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Kailas S. Khomane
- Department
of Pharmaceutics, ‡Department of Pharmacoinformatics, §Department of Medicinal Chemistry, and ∥Department of
Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67,
SAS Nagar, Mohali, Punjab, India
| | - Prajwal P. Nandekar
- Department
of Pharmaceutics, ‡Department of Pharmacoinformatics, §Department of Medicinal Chemistry, and ∥Department of
Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67,
SAS Nagar, Mohali, Punjab, India
| | - Banrida Wahlang
- Department
of Pharmaceutics, ‡Department of Pharmacoinformatics, §Department of Medicinal Chemistry, and ∥Department of
Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67,
SAS Nagar, Mohali, Punjab, India
| | - Pravin Bagul
- Department
of Pharmaceutics, ‡Department of Pharmacoinformatics, §Department of Medicinal Chemistry, and ∥Department of
Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67,
SAS Nagar, Mohali, Punjab, India
| | - Naeem Shaikh
- Department
of Pharmaceutics, ‡Department of Pharmacoinformatics, §Department of Medicinal Chemistry, and ∥Department of
Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67,
SAS Nagar, Mohali, Punjab, India
| | - Yogesh B. Pawar
- Department
of Pharmaceutics, ‡Department of Pharmacoinformatics, §Department of Medicinal Chemistry, and ∥Department of
Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67,
SAS Nagar, Mohali, Punjab, India
| | - Chhuttan Lal Meena
- Department
of Pharmaceutics, ‡Department of Pharmacoinformatics, §Department of Medicinal Chemistry, and ∥Department of
Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67,
SAS Nagar, Mohali, Punjab, India
| | - Abhay T. Sangamwar
- Department
of Pharmaceutics, ‡Department of Pharmacoinformatics, §Department of Medicinal Chemistry, and ∥Department of
Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67,
SAS Nagar, Mohali, Punjab, India
| | - Rahul Jain
- Department
of Pharmaceutics, ‡Department of Pharmacoinformatics, §Department of Medicinal Chemistry, and ∥Department of
Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67,
SAS Nagar, Mohali, Punjab, India
| | - K. Tikoo
- Department
of Pharmaceutics, ‡Department of Pharmacoinformatics, §Department of Medicinal Chemistry, and ∥Department of
Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67,
SAS Nagar, Mohali, Punjab, India
| | - Arvind K. Bansal
- Department
of Pharmaceutics, ‡Department of Pharmacoinformatics, §Department of Medicinal Chemistry, and ∥Department of
Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67,
SAS Nagar, Mohali, Punjab, India
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