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Parisien M, Grant AV, Muralidharan A, Diatchenko L, Mogil JS. Chronic pain and premature mortality in men and women, using data from UK Biobank. Reply. J Clin Invest 2023; 133:168070. [PMID: 36856114 PMCID: PMC9974091 DOI: 10.1172/jci168070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023] Open
Affiliation(s)
- Marc Parisien
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
| | - Audrey V. Grant
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
| | - Arjun Muralidharan
- Charles Perkin Centre, Faculty of Science, University of Sydney, New South Wales, Australia
| | - Luda Diatchenko
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
| | - Jeffrey S. Mogil
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
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Smith AE, Muralidharan A, Smith MT. Prostate cancer induced bone pain: pathobiology, current treatments and pain responses from recent clinical trials. Discov Oncol 2022; 13:108. [PMID: 36258057 PMCID: PMC9579264 DOI: 10.1007/s12672-022-00569-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 09/29/2022] [Indexed: 11/04/2022] Open
Abstract
PURPOSE Metastatic spread of prostate cancer to the skeleton may result in debilitating bone pain. In this review, we address mechanisms underpinning the pathobiology of metastatic prostate cancer induced bone pain (PCIBP) that include sensitization and sprouting of primary afferent sensory nerve fibres in bone. We also review current treatments and pain responses evoked by various treatment modalities in clinical trials in this patient population. METHODS We reviewed the literature using PubMed to identify research on the pathobiology of PCIBP. Additionally, we reviewed clinical trials of various treatment modalities in patients with PCIBP with pain response outcomes published in the past 7 years. RESULTS Recent clinical trials show that radionuclides, given either alone or in combination with chemotherapy, evoked favourable pain responses in many patients and a single fraction of local external beam radiation therapy was as effective as multiple fractions. However, treatment with chemotherapy, small molecule inhibitors and/or immunotherapy agents, produced variable pain responses but pain response was the primary endpoint in only one of these trials. Additionally, there were no published trials of potentially novel analgesic agents in patients with PCIBP. CONCLUSION There is a knowledge gap for clinical trials of chemotherapy, small molecule inhibitors and/or immunotherapy in patients with PCIBP where pain response is the primary endpoint. Also, there are no novel analgesic agents on the horizon for the relief of PCIBP and this is an area of large unmet medical need that warrants concerted research attention.
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Affiliation(s)
- A. E. Smith
- St Vincent’s Hospital, Darlinghurst, Sydney, NSW Australia
| | - A. Muralidharan
- Neurobiology of Chronic Pain, The Charles Perkins Centre, Faculty of Science, The University of Sydney, Sydney, NSW 2006 Australia
| | - M. T. Smith
- Centre for Integrated Preclinical Drug Development, School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia Campus, Brisbane, QLD 4072 Australia
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Muralidharan A, Sotocinal SG, Yousefpour N, Akkurt N, Lima LV, Tansley S, Parisien M, Wang C, Austin JS, Ham B, Dutra GM, Rousseau P, Maldonado-Bouchard S, Clark T, Rosen SF, Majeed MR, Silva O, Nejade R, Li X, Donayre Pimentel S, Nielsen CS, Neely GG, Autexier C, Diatchenko L, Ribeiro-da-Silva A, Mogil JS. Long-term male-specific chronic pain via telomere- and p53‑mediated spinal cord cellular senescence. J Clin Invest 2022; 132:151817. [PMID: 35426375 PMCID: PMC9012275 DOI: 10.1172/jci151817] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 03/08/2022] [Indexed: 12/13/2022] Open
Abstract
Mice with experimental nerve damage can display long‑lasting neuropathic pain behavior. We show here that 4 months and later after nerve injury, male but not female mice displayed telomere length (TL) reduction and p53‑mediated cellular senescence in the spinal cord, resulting in maintenance of pain and associated with decreased lifespan. Nerve injury increased the number of p53‑positive spinal cord neurons, astrocytes, and microglia, but only in microglia was the increase male‑specific, matching a robust sex specificity of TL reduction in this cell type, which has been previously implicated in male‑specific pain processing. Pain hypersensitivity was reversed by repeated intrathecal administration of a p53‑specific senolytic peptide, only in male mice and only many months after injury. Analysis of UK Biobank data revealed sex-specific relevance of this pathway in humans, featuring male‑specific genetic association of the human p53 locus (TP53) with chronic pain and a male-specific effect of chronic pain on mortality. Our findings demonstrate the existence of a biological mechanism maintaining pain behavior, at least in males, occurring much later than the time span of virtually all extant preclinical studies.
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Affiliation(s)
- Arjun Muralidharan
- Department of Psychology, McGill University, Montreal, Quebec, Canada
- Charles Perkins Centre, The University of Sydney, Camperdown, New South Wales, Australia
| | | | | | - Nur Akkurt
- Department of Psychology, McGill University, Montreal, Quebec, Canada
| | - Lucas V. Lima
- Department of Psychology, McGill University, Montreal, Quebec, Canada
| | - Shannon Tansley
- Department of Psychology, McGill University, Montreal, Quebec, Canada
| | | | - Chengyang Wang
- Department of Psychology, McGill University, Montreal, Quebec, Canada
| | | | - Boram Ham
- Department of Psychology, McGill University, Montreal, Quebec, Canada
| | | | - Philippe Rousseau
- Bloomfield Centre for Research in Aging, McGill University, Montreal, Quebec, Canada
| | | | - Teleri Clark
- Charles Perkins Centre, The University of Sydney, Camperdown, New South Wales, Australia
| | - Sarah F. Rosen
- Department of Psychology, McGill University, Montreal, Quebec, Canada
| | - Mariam R. Majeed
- Department of Psychology, McGill University, Montreal, Quebec, Canada
| | - Olivia Silva
- Department of Psychology, McGill University, Montreal, Quebec, Canada
| | - Rachel Nejade
- Department of Psychology, McGill University, Montreal, Quebec, Canada
| | - Xinyu Li
- Charles Perkins Centre, The University of Sydney, Camperdown, New South Wales, Australia
| | | | - Christopher S. Nielsen
- Department of Chronic Diseases and Ageing, Norwegian Institute of Public Health, Oslo, Norway
- Department of Pain Management and Research, Oslo University Hospital, Oslo, Norway
| | - G. Gregory Neely
- Charles Perkins Centre, The University of Sydney, Camperdown, New South Wales, Australia
| | - Chantal Autexier
- Bloomfield Centre for Research in Aging, McGill University, Montreal, Quebec, Canada
| | | | | | - Jeffrey S. Mogil
- Department of Psychology, McGill University, Montreal, Quebec, Canada
- Department of Anesthesia, McGill University, Montreal, Quebec, Canada
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Pratt LR, Gomez DT, Muralidharan A, Pesika N. Shapes of Nonsymmetric Capillary Bridges. J Phys Chem B 2021; 125:12378-12383. [PMID: 34709808 PMCID: PMC8591610 DOI: 10.1021/acs.jpcb.1c07448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Here we study the shapes of droplets captured between chemically distinct parallel plates. This work is a preliminary step toward characterizing the influence of second-phase bridging between biomolecular surfaces on their solution contacts, i.e., capillary attraction or repulsion. We obtain a simple, variable-separated quadrature formula for the bridge shape. The technical complication of double-ended boundary conditions on the shapes of nonsymmetric bridges is addressed by studying waists in the bridge shape, i.e., points where the bridge silhouette has zero derivative. Waists are generally expected with symmetric bridges, but waist points can serve to characterize shape segments in general cases. We study how waist possibilities depend on the physical input to these problems, noting that these formulas change with the sign of the inside-outside pressure difference of the bridge. These results permit a variety of different interesting shapes, and the development below is accompanied by several examples.
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Affiliation(s)
- L R Pratt
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
| | - D T Gomez
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
| | - A Muralidharan
- Department of Chemistry, University of Wisconsin─Madison, Madison, Wisconson 53706, United States
| | - N Pesika
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
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Gilham D, Smith AL, Fu L, Moore DY, Muralidharan A, Reid SPM, Stotz SC, Johansson JO, Sweeney M, Wong NCW, El-Gamal D, Kulikowski E. Bromodomain and extraterminal (BET) protein inhibitor, apabetalone, reduces ACE2 expression and attenuates SARS-CoV-2 infection in vitro. Eur Heart J 2021. [PMCID: PMC8767620 DOI: 10.1093/eurheartj/ehab724.3267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background/Introduction SARS-CoV-2 causes life threatening COVID-19 complications including acute coronary syndrome, venous thromboembolism, hyperinflammation and damage in multiple tissues. The SARS-CoV-2 “spike protein” binds cell surface receptors including angiotensin-converting enzyme 2 (ACE2) for entry into host cells to initiate infection. Host cell dipeptidyl peptidase-4 (DPP4 / CD26) is implicated as a cofactor in uptake. Recent evidence indicates expression of factors involved in SARS-CoV-2 uptake into host cells is regulated by BET proteins, epigenetic readers modulating gene expression. Apabetalone, the most clinically advanced BET inhibitor (BETi), is in phase 3 trials for cardiovascular disease (CVD) (a,b). In cultured human cardiomyocytes, apabetalone suppressed infection with SARS-CoV-2 and prevented dysfunction of cardiac organoids induced by the cytokine-storm that arises in patients with severe symptoms (c). However, anti-viral properties of apabetalone in other cell types are not known. Purpose To examine effects of apabetalone on SARS-CoV-2 infection in cell culture via downregulated expression of cell surface receptors involved in viral entry. Cell systems used mimic initial sites of infection in the lung as well as cell types contributing to complications in late stages of infection. Methods Gene expression was measured by real-time PCR, protein levels by immunoblot or flow cytometry, and binding of recombinant SARS-CoV-2 spike protein by flow cytometry. Infection with SARS-CoV-2 was determined in a BSL3 facility. Infectivity was quantified by determining levels of viral spike protein amongst total cells via imaging on an Operetta CLS. Results In Calu-3, a human bronchial epithelial cell line, apabetalone dose-dependently downregulated ACE2 gene expression (up to 98%), reduced ACE2 protein levels (up to 84%) and diminished binding of SARS-CoV-2 spike protein (up to 77%, p<0.001 for all parameters). Further, apabetalone abolished infection of Calu-3 cells with live SARS-CoV-2, which was comparable to other antiviral agents. Apabetalone-driven ACE2 downregulation was also observed in extrapulmonary cell types including HepG2, Huh-7 or primary hepatocytes (up to 90%, p<0.001 for all cell types), and Vero E6, a monkey kidney epithelial cell line (up to 38%, p<0.05). DPP4/CD26, a potential cofactor for SARS-CoV-2 uptake, was also downregulated by apabetalone in Calu-3 cells (mRNA ∼65% and protein ∼40%, p<0.001), which may be synergistic with ACE2 reductions to impede SARS-CoV-2 infection. Conclusions Apabetalone, an investigational drug for CVD, reduced cell surface receptors (ACE2 and DPP4) involved in SARS-CoV-2 uptake into host cells and dramatically attenuated SARS-CoV-2 infection/propagation in vitro. Our results suggest apabetalone can mitigate SARS-CoV-2 replication in multiple organs, which together with an established safety profile supports clinical evaluation of apabetalone to treat Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): COVID-19 Rapid Response Grant from the College of Medicine at the University of Nebraska Medical Center (to DE and SPMR), and by University of Nebraska Medical Center start-up funds (to DE).
Graphical Abstract ![]()
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Affiliation(s)
- D Gilham
- Resverlogix Corp., Calgary, Canada
| | - A L Smith
- University of Nebraska Medical Center, Eppley Institute for Research in Cancer and Allied Diseases, Omaha, United States of America
| | - L Fu
- Resverlogix Corp., Calgary, Canada
| | - D Y Moore
- University of Nebraska Medical Center, Eppley Institute for Research in Cancer and Allied Diseases, Omaha, United States of America
| | - A Muralidharan
- University of Nebraska Medical Center, Department of Pathology and Microbiology, Omaha, United States of America
| | - S P M Reid
- University of Nebraska Medical Center, Department of Pathology and Microbiology, Omaha, United States of America
| | | | - J O Johansson
- Resverlogix Inc., San Francisco, United States of America
| | - M Sweeney
- Resverlogix Inc., San Francisco, United States of America
| | | | - D El-Gamal
- University of Nebraska Medical Center, Eppley Institute for Research in Cancer and Allied Diseases, Omaha, United States of America
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Muralidharan A, Samoshkin A, Convertino M, Piltonen MH, Gris P, Wang J, Jiang C, Klares R, Linton A, Ji RR, Maixner W, Dokholyan NV, Mogil JS, Diatchenko L. Identification and characterization of novel candidate compounds targeting 6- and 7-transmembrane μ-opioid receptor isoforms. Br J Pharmacol 2021; 178:2709-2726. [PMID: 33782947 PMCID: PMC10697213 DOI: 10.1111/bph.15463] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 03/15/2021] [Accepted: 03/18/2021] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND AND PURPOSE The μ-opioid receptor (μ receptor) is the primary target for opioid analgesics. The 7-transmembrane (TM) and 6TM μ receptor isoforms mediate inhibitory and excitatory cellular effects. Here, we developed compounds selective for 6TM- or 7TM-μ receptors to further our understanding of the pharmacodynamic properties of μ receptors. EXPERIMENTAL APPROACH We performed virtual screening of the ZINC Drug Now library of compounds using in silico 7TM- and 6TM-μ receptor structural models and identified potential compounds that are selective for 6TM- and/or 7TM-μ receptors. Subsequently, we characterized the most promising candidate compounds in functional in vitro studies using Be2C neuroblastoma transfected cells, behavioural in vivo pain assays using various knockout mice and in ex vivo electrophysiology studies. KEY RESULTS Our virtual screen identified 30 potential candidate compounds. Subsequent functional in vitro cellular assays shortlisted four compounds (#5, 10, 11 and 25) that demonstrated 6TM- or 7TM-μ receptor-dependent NO release. In in vivo pain assays these compounds also produced dose-dependent hyperalgesic responses. Studies using mice that lack specific opioid receptors further established the μ receptor-dependent nature of identified novel ligands. Ex vivo electrophysiological studies on spontaneous excitatory postsynaptic currents in isolated spinal cord slices also validated the hyperalgesic properties of the most potent 6TM- (#10) and 7TM-μ receptor (#5) ligands. CONCLUSION AND IMPLICATIONS Our novel compounds represent a new class of ligands for μ receptors and will serve as valuable research tools to facilitate the development of opioids with significant analgesic efficacy and fewer side-effects.
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Affiliation(s)
- Arjun Muralidharan
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
- Department of Psychology, McGill University, Montreal, Quebec, Canada
| | - Alexander Samoshkin
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
- Department of Anesthesia, McGill University, Montreal, Quebec, Canada
| | - Marino Convertino
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Marjo Hannele Piltonen
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
| | - Pavel Gris
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
| | - Jian Wang
- Department of Pharmacology, and Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Changyu Jiang
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Richard Klares
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
- Department of Anesthesia, McGill University, Montreal, Quebec, Canada
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
| | - Alexander Linton
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
- Department of Anesthesia, McGill University, Montreal, Quebec, Canada
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
| | - Ru-Rong Ji
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina, USA
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, USA
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
| | - William Maixner
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Nikolay V. Dokholyan
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA
- Department of Pharmacology, and Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Jeffrey S. Mogil
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
- Department of Psychology, McGill University, Montreal, Quebec, Canada
- Department of Anesthesia, McGill University, Montreal, Quebec, Canada
| | - Luda Diatchenko
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
- Department of Anesthesia, McGill University, Montreal, Quebec, Canada
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
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Muralidharan A, Sotocinal SG, Austin JS, Mogil JS. The influence of aging and duration of nerve injury on the antiallodynic efficacy of analgesics in laboratory mice. Pain Rep 2020; 5:e824. [PMID: 32903926 PMCID: PMC7447376 DOI: 10.1097/pr9.0000000000000824] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/21/2020] [Accepted: 04/25/2020] [Indexed: 11/26/2022] Open
Abstract
INTRODUCTION Increasing attention is being paid to the effects of organismic factors like age on pain sensitivity. However, very little data exist on this topic using modern algesiometric assays and measures in laboratory rodents. OBJECTIVES We investigated the effect of age and duration of nerve injury on baseline mechanical thresholds, neuropathic allodynia, and the antiallodynic and analgesic efficacy of 4 systemically administered analgesics: amitriptyline, diclofenac, morphine, and pregabalin. METHODS Mice of both sexes and 3 conditions were compared: Young-Young, in which baseline testing (von Frey thresholds), the injury producing neuropathic pain (spared nerve injury [SNI]) and subsequent drug testing occurred while mice were young (8-10 weeks); Young-Old, in which mice received the nerve injury while young but were tested for drug efficacy over 10 months later; and Old-Old, in which both the nerve injury and drug testing occurred at approximately 1 year of age. RESULTS Old-Old mice were found to display higher baseline mechanical sensitivity than other groups. No group differences were seen in SNI-induced allodynia in males; female Young-Old mice were found to display greatly reduced allodynia. With respect to drug efficacy, no differences among conditions were observed for amitriptyline, diclofenac, or morphine. For pregabalin, however, Young-Old mice displayed significantly reduced antiallodynia, and the drug was completely ineffective in Old-Old mice. CONCLUSION Novel findings include the apparent remission of SNI-induced allodynia in female mice 10 months after injury and reduced pregabalin antiallodynic effects produced by both the passage of time after nerve injury and aging.
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Affiliation(s)
- Arjun Muralidharan
- Department of Psychology and Anesthesia, McGill University, Montreal, QC, Canada
| | - Susana G. Sotocinal
- Department of Psychology and Anesthesia, McGill University, Montreal, QC, Canada
| | | | - Jeffrey S. Mogil
- Department of Psychology and Anesthesia, McGill University, Montreal, QC, Canada
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Muralidharan A, Pratt L, Chaudhari M, Rempe S. Quasi-chemical theory for anion hydration and specific ion effects: Cl-(aq) vs. F-(aq). ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.cpletx.2019.100037] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Khuong TM, Hamoudi Z, Manion J, Loo L, Muralidharan A, Neely GG. Peripheral straightjacket (α2δ Ca 2+ channel subunit) expression is required for neuropathic sensitization in Drosophila. Philos Trans R Soc Lond B Biol Sci 2019; 374:20190287. [PMID: 31544607 DOI: 10.1098/rstb.2019.0287] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Nerve injury leads to devastating and often untreatable neuropathic pain. While acute noxious sensation (nociception) is a crucial survival mechanism and is conserved across phyla, chronic neuropathic pain is considered a maladaptive response owing to its devastating impact on a patient's quality of life. We have recently shown that a neuropathic pain-like response occurs in adult Drosophila. However, the mechanisms underlying this phenomenon are largely unknown. Previous studies have shown that the α2δ peripheral calcium channel subunit straightjacket (stj) is a conserved factor required for thermal pain perception. We demonstrate here that stj is required in peripheral ppk+ sensory neurons for acute thermal responses and that it mediates nociceptive hypersensitivity in an adult Drosophila model of neuropathic pain-like disease. Given that calcium channels are the main targets of gabapentinoids (pregabalin and gabapentin), we assessed if these drugs can alleviate nociceptive hypersensitivity. Our findings suggest that gabapentinoids may prevent nociceptive hypersensitivity by preserving central inhibition after nerve injury. Together, our data further highlight the similarity of some mechanisms for pain-like conditions across phyla and validates the scientific use of Drosophila neuropathic sensitization models for analgesic drug discovery. This article is part of the Theo Murphy meeting issue 'Evolution of mechanisms and behaviour important for pain'.
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Affiliation(s)
- Thang M Khuong
- The Dr John and Anne Chong Laboratory for Functional Genomics, Charles Perkins Centre and School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Zina Hamoudi
- The Dr John and Anne Chong Laboratory for Functional Genomics, Charles Perkins Centre and School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - John Manion
- The Dr John and Anne Chong Laboratory for Functional Genomics, Charles Perkins Centre and School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Lipin Loo
- The Dr John and Anne Chong Laboratory for Functional Genomics, Charles Perkins Centre and School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Arjun Muralidharan
- The Dr John and Anne Chong Laboratory for Functional Genomics, Charles Perkins Centre and School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - G Gregory Neely
- The Dr John and Anne Chong Laboratory for Functional Genomics, Charles Perkins Centre and School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales 2006, Australia
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Muralidharan A, Pratt LR, Chaudhari MI, Rempe SB. Quasi-Chemical Theory with Cluster Sampling from Ab Initio Molecular Dynamics: Fluoride (F -) Anion Hydration. J Phys Chem A 2018; 122:9806-9812. [PMID: 30475612 DOI: 10.1021/acs.jpca.8b08474] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Accurate predictions of the hydration free energy for anions typically has been more challenging than that for cations. Hydrogen bond donation to the anion in hydrated clusters such as F(H2O) n - can lead to delicate structures. Consequently, the energy landscape contains many local minima, even for small clusters, and these minima present a challenge for computational optimization. Utilization of cluster experimental results for the free energies of gas-phase clusters shows that even though anharmonic effects are interesting they need not be of troublesome magnitudes for careful applications of quasi-chemical theory to ion hydration. Energy-optimized cluster structures for anions can leave the central ion highly exposed, and application of implicit solvation models to these structures can incur more serious errors than those for metal cations. Utilizing cluster structures sampled from ab initio molecular dynamics simulations substantially fixes those issues.
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Affiliation(s)
- A Muralidharan
- Department of Chemical and Biomolecular Engineering , Tulane University , New Orleans , Louisiana 70118 , United States
| | - L R Pratt
- Department of Chemical and Biomolecular Engineering , Tulane University , New Orleans , Louisiana 70118 , United States
| | - M I Chaudhari
- Center for Biological and Engineering Sciences , Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
| | - S B Rempe
- Center for Biological and Engineering Sciences , Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
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Muralidharan A, Havrilla S, Schneider RG, Lucksted A, Goldberg R. PEER COACHING TO PROMOTE SUPERVISED FITNESS TRAINING FOR OLDER VETERANS WITH PSYCHOTIC DISORDERS. Innov Aging 2018. [DOI: 10.1093/geroni/igy023.2206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A Muralidharan
- Veterans Affairs Capitol Healthcare Network, Baltimore, MD USA, Baltimore, Maryland, United States
| | - S Havrilla
- Veterans Affairs Capitol Healthcare Network, Baltimore, MD, USA
| | - R G Schneider
- Veterans Affairs Capitol Healthcare Network, Baltimore, MD USA
| | - A Lucksted
- Veterans Affairs Capitol Healthcare Network, Baltimore, MD, USA; University of Maryland School of Medicine, Department of Psychiatry, Baltimore, MD USA
| | - R Goldberg
- Veterans Affairs Capitol Healthcare Network, Baltimore, MD, USA; University of Maryland School of Medicine, Department of Psychiatry, Baltimore, MD, USA
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Muralidharan A, Karel MJ. INTEREST GROUP SESSION - MENTAL HEALTH PRACTICE AND AGING: HOLISTIC RECOVERY FROM MENTAL ILLNESS FOR OLDER VETERANS. Innov Aging 2018. [DOI: 10.1093/geroni/igy023.2205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- A Muralidharan
- Veterans Affairs Capitol Healthcare Network, Baltimore, MD USA, Baltimore, Maryl
| | - M J Karel
- Office of Mental Health and Suicide Prevention, Department of Veterans Affairs, Underhill, Vermont
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Abstract
Laying a basis for molecularly specific theory for the mobilities of ions in solutions of practical interest, we report a broad survey of velocity autocorrelation functions (VACFs) of Li+ and PF6- ions in water, ethylene carbonate, propylene carbonate, and acetonitrile solutions. We extract the memory function, γ(t), which characterizes the random forces governing the mobilities of ions. We provide comparisons controlling for the effects of electrolyte concentration and ion-pairing, van der Waals attractive interactions, and solvent molecular characteristics. For the heavier ion (PF6-), velocity relaxations are all similar: negative tail relaxations for the VACF and a clear second relaxation for γt, observed previously also for other molecular ions and with n-pentanol as the solvent. For the light Li+ ion, short time-scale oscillatory behavior masks simple, longer time-scale relaxation of γt. But the corresponding analysis of the solventberg Li+H2O4 does conform to the standard picture set by all the PF6- results.
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Affiliation(s)
- A Muralidharan
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, USA
| | - L R Pratt
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, USA
| | - M I Chaudhari
- Sandia National Laboratories, Center for Biological and Engineering Sciences, Albuquerque, New Mexico 87185, USA
| | - S B Rempe
- Sandia National Laboratories, Center for Biological and Engineering Sciences, Albuquerque, New Mexico 87185, USA
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Khan N, Muralidharan A, Smith MT. Attenuation of the Infiltration of Angiotensin II Expressing CD3 + T-Cells and the Modulation of Nerve Growth Factor in Lumbar Dorsal Root Ganglia - A Possible Mechanism Underpinning Analgesia Produced by EMA300, An Angiotensin II Type 2 (AT 2) Receptor Antagonist. Front Mol Neurosci 2017; 10:389. [PMID: 29200998 PMCID: PMC5696600 DOI: 10.3389/fnmol.2017.00389] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/07/2017] [Indexed: 12/25/2022] Open
Abstract
Recent preclinical and proof-of-concept clinical studies have shown promising analgesic efficacy of selective small molecule angiotensin II type 2 (AT2) receptor antagonists in the alleviation of peripheral neuropathic pain. However, their cellular and molecular mechanism of action requires further investigation. To address this issue, groups of adult male Sprague–Dawley rats with fully developed unilateral hindpaw hypersensitivity, following chronic constriction injury (CCI) of the sciatic nerve, received a single intraperitoneal bolus dose of the small molecule AT2 receptor antagonist, EMA300 (10 mg kg-1), or vehicle. At the time of peak EMA300-mediated analgesia (∼1 h post-dosing), groups of CCI-rats administered either EMA300 or vehicle were euthanized. A separate group of rats that underwent sham surgery were also included. The lumbar (L4–L6) dorsal root ganglia (DRGs) were obtained from all experimental cohorts and processed for immunohistochemistry and western blot studies. In vehicle treated CCI-rats, there was a significant increase in the expression levels of angiotensin II (Ang II), but not the AT2 receptor, in the ipsilateral lumbar DRGs. The elevated levels of Ang II in the ipsilateral lumbar DRGs of CCI-rats were at least in part contributed by CD3+ T-cells, satellite glial cells (SGCs) and subsets of neurons. Our findings suggest that the analgesic effect of EMA300 in CCI-rats involves multimodal actions that appear to be mediated at least in part by a significant reduction in the otherwise increased expression levels of Ang II as well as the number of Ang II-expressing CD3+ T-cells in the ipsilateral lumbar DRGs of CCI-rats. Additionally, the acute anti-allodynic effects of EMA300 in CCI-rats were accompanied by rescue of the otherwise decreased expression of mature nerve growth factor (NGF) in the ipsilateral lumbar DRGs of CCI-rats. In contrast, the increased expression levels of TrkA and glial fibrillary acidic protein in the ipsilateral lumbar DRGs of vehicle-treated CCI-rats were not attenuated by a single bolus dose of EMA300. Consistent with our previous findings, there was also a significant decrease in the augmented levels of the downstream mediators of Ang II/AT2 receptor signaling, i.e., phosphorylated-p38 mitogen-activated protein kinase (MAPK) and phosphorylated-p44/p42 MAPK, in the ipsilateral lumbar DRGs.
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Affiliation(s)
- Nemat Khan
- UQ Center for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Arjun Muralidharan
- UQ Center for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Maree T Smith
- UQ Center for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia.,School of Pharmacy, Faculty of Health and Behavioural Sciences, The University of Queensland, Brisbane, QLD, Australia
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Hashimoto T, Yoshida K, Goto T, Yako T, Muralidharan A, Baker K, Vitek J. Thalamic responses to somatosensory input are reduced in cerebellar ataxia. J Neurol Sci 2017. [DOI: 10.1016/j.jns.2017.08.862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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17
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Muralidharan A, Park TSW, Mackie JT, Gimenez LGS, Kuo A, Nicholson JR, Corradini L, Smith MT. Establishment and Characterization of a Novel Rat Model of Mechanical Low Back Pain Using Behavioral, Pharmacologic and Histologic Methods. Front Pharmacol 2017; 8:493. [PMID: 28798688 PMCID: PMC5529395 DOI: 10.3389/fphar.2017.00493] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 07/10/2017] [Indexed: 11/22/2022] Open
Abstract
Chronic low back pain (LBP), the leading cause of disability globally, is notoriously difficult to treat. Most rodent models of LBP mimic lumbar radicular pain rather than mechanical LBP. Here, we describe establishment of a new rat model of mechanical LBP that is devoid of a neuropathic component. Groups of adult male Sprague Dawley rats were anesthetized and their lumbar L4/L5 and L5/L6 intervertebral disks (IVDs) were punctured (0.5 mm outer diameter, 2mm-deep) 5 (LPB-5X), or 10 (LBP-10X) times per disk. Sham-rats underwent similar surgery, but without disk puncture. Baseline noxious pressure hyperalgesia of lumbar axial deep tissues, mechanical allodynia in the hindpaws and gait were assessed prior to surgery and once-weekly until study completion on day 49. The model was also characterized using pharmacologic and histologic methods. Good animal health was maintained for ≥ 49 days post-surgery. For LBP- but not sham-rats, there was temporal development of noxious pressure hyperalgesia in lumbar axial deep tissues at days 14–49 post-surgery. Importantly, there were no between-group differences in von Frey paw withdrawal thresholds or gait parameters until study completion. On day 49, significant histologic changes were observed in the L4/L5 and L5/L6 IVDs for LBP-10X rats, but not sham-rats. In LBP-10X rats, single bolus doses of morphine produced dose-dependent relief of primary and secondary mechanical hyperalgesia in lumbar axial deep tissues at L4/L5 and L1, respectively. In conclusion, our new rat model has considerable potential for providing novel insight on the pathobiology of mechanical LBP and for analgesic efficacy assessment of novel compounds.
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Affiliation(s)
- Arjun Muralidharan
- Centre for Integrated Preclinical Drug Development, The University of Queensland, BrisbaneQLD, Australia
| | - Thomas S W Park
- Centre for Integrated Preclinical Drug Development, The University of Queensland, BrisbaneQLD, Australia
| | - John T Mackie
- School of Veterinary Science, The University of Queensland, GattonQLD, Australia
| | - Luiz G S Gimenez
- Centre for Integrated Preclinical Drug Development, The University of Queensland, BrisbaneQLD, Australia
| | - Andy Kuo
- Centre for Integrated Preclinical Drug Development, The University of Queensland, BrisbaneQLD, Australia
| | | | | | - Maree T Smith
- Centre for Integrated Preclinical Drug Development, The University of Queensland, BrisbaneQLD, Australia.,School of Pharmacy, The University of Queensland, BrisbaneQLD, Australia
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Avinesh MP, Jaison MTJ, Sajith AM, Nagaswarupa HP, Muralidharan A. Facile Synthesis of Fully Decorated Imidazo[4,5-b] and Imidazo[4,5-c] Pyridines in Aqueous DMF via C-H Activation under Microwave Irradiation. ChemistrySelect 2016. [DOI: 10.1002/slct.201600374] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Mr. P. Avinesh
- Research and development centre; Bharathiyar University; Coimbatore
- Research Centre; Department of Chemistry; East West Institute of Technology; Bangalore India
| | - Mr. Thadathil. J. Jaison
- Research and development centre; Bharathiyar University; Coimbatore
- Research Centre; Department of Chemistry; East West Institute of Technology; Bangalore India
| | - Ayyiliath. M. Sajith
- Department of Chemistry; Nehru Arts and Science College; Kannur University; Kannur India
- Post Graduate and Research Department of Chemistry; Government College Kasargod; Kannur University; Kannur India
| | - H. P. Nagaswarupa
- Research and development centre; Bharathiyar University; Coimbatore
- Research Centre; Department of Chemistry; East West Institute of Technology; Bangalore India
| | - A. Muralidharan
- Post Graduate and Research Department of Chemistry; Government College Kasargod; Kannur University; Kannur India
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Muralidharan A, Kuo A, Jacob M, Lourdesamy JS, Carvalho LMSPD, Nicholson JR, Corradini L, Smith MT. Comparison of Burrowing and Stimuli-Evoked Pain Behaviors as End-Points in Rat Models of Inflammatory Pain and Peripheral Neuropathic Pain. Front Behav Neurosci 2016; 10:88. [PMID: 27242458 PMCID: PMC4862327 DOI: 10.3389/fnbeh.2016.00088] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 04/22/2016] [Indexed: 01/30/2023] Open
Abstract
Establishment and validation of ethologically-relevant, non-evoked behavioral end-points as surrogate measures of spontaneous pain in rodent pain models has been proposed as a means to improve preclinical to clinical research translation in the pain field. Here, we compared the utility of burrowing behavior with hypersensitivity to applied mechanical stimuli for pain assessment in rat models of chronic inflammatory and peripheral neuropathic pain. Briefly, groups of male Sprague-Dawley rats were habituated to the burrowing environment and trained over a 5-day period. Rats that burrowed ≤ 450 g of gravel on any 2 days of the individual training phase were excluded from the study. The remaining rats received either a unilateral intraplantar injection of Freund's complete adjuvant (FCA) or saline, or underwent unilateral chronic constriction injury (CCI) of the sciatic nerve- or sham-surgery. Baseline burrowing behavior and evoked pain behaviors were assessed prior to model induction, and twice-weekly until study completion on day 14. For FCA- and CCI-rats, but not the corresponding groups of sham-rats, evoked mechanical hypersensitivity developed in a temporal manner in the ipsilateral hindpaws. Although burrowing behavior also decreased in a temporal manner for both FCA-and CCI- rats, there was considerable inter-animal variability. By contrast, mechanical hyperalgesia and mechanical allodynia in the ipsilateral hindpaws of FCA- and CCI-rats respectively, exhibited minimal inter-animal variability. Our data collectively show that burrowing behavior is altered in rodent models of chronic inflammatory pain and peripheral neuropathic pain. However, large group sizes are needed to ensure studies are adequately powered due to considerable inter-animal variability.
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Affiliation(s)
- Arjun Muralidharan
- Centre for Integrated Preclinical Drug Development, The University of Queensland Brisbane, QLD, Australia
| | - Andy Kuo
- Centre for Integrated Preclinical Drug Development, The University of Queensland Brisbane, QLD, Australia
| | - Meera Jacob
- Centre for Integrated Preclinical Drug Development, The University of Queensland Brisbane, QLD, Australia
| | - Jacintha S Lourdesamy
- Centre for Integrated Preclinical Drug Development, The University of Queensland Brisbane, QLD, Australia
| | | | - Janet R Nicholson
- Department of CNS Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG Biberach, Germany
| | - Laura Corradini
- Department of CNS Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG Biberach, Germany
| | - Maree T Smith
- Centre for Integrated Preclinical Drug Development, The University of QueenslandBrisbane, QLD, Australia; School of Pharmacy, The University of Queensland, St Lucia CampusBrisbane, QLD, Australia
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Muralidharan A, Jensen AL, Connolly A, Hendrix CM, Johnson MD, Baker KB, Vitek JL. Physiological changes in the pallidum in a progressive model of Parkinson's disease: Are oscillations enough? Exp Neurol 2016; 279:187-196. [PMID: 26946223 DOI: 10.1016/j.expneurol.2016.03.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 02/29/2016] [Accepted: 03/01/2016] [Indexed: 11/17/2022]
Abstract
Neurophysiological changes in the basal ganglia thalamo-cortical circuit associated with the development of parkinsonian motor signs remain poorly understood. Theoretical models have ranged from those emphasizing changes in mean discharge rate to increased oscillatory activity within the beta range. The present study characterized neuronal activity within and across the internal and external segments of the globus pallidus as a function of motor severity using a staged, progressively severe 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of Parkinsonism in three rhesus monkeys. An increase in coherence between neuronal pairs across the external and internal globus pallidus was present in multiple frequency bands in the parkinsonian state; both the peak frequency of oscillatory coherence and the variability were reduced in the parkinsonian state. The incidence of 8-20Hz oscillatory activity in the internal globus pallidus increased with the progression of the disease when pooling the data across the three animals; however it did not correlate with motor severity when assessed individually and increased progressively in only one of three animals. No systematic relationship between mean discharge rates or the incidence or structure of bursting activity and motor severity was observed. These data suggest that exaggerated coupling across pallidal segments contribute to the development of the parkinsonian state by inducing an exaggerated level of synchrony and loss of focusing within the basal ganglia. These data further point to the lack of a defined relationship between rate changes, the mere presence of oscillatory activity in the beta range and bursting activity in the basal ganglia to the motor signs of Parkinson's disease.
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Affiliation(s)
- A Muralidharan
- Department of Neurology, University of Minnesota, Minneapolis, MN 55455, United States
| | - A L Jensen
- Department of Neurology, University of Minnesota, Minneapolis, MN 55455, United States
| | - A Connolly
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, United States
| | - C M Hendrix
- Department of Neurology, University of Minnesota, Minneapolis, MN 55455, United States
| | - M D Johnson
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, United States
| | - K B Baker
- Department of Neurology, University of Minnesota, Minneapolis, MN 55455, United States
| | - J L Vitek
- Department of Neurology, University of Minnesota, Minneapolis, MN 55455, United States.
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Savitha B, Sajith AM, Joy MN, Khader KA, Muralidharan A, Padusha MSA, Bodke YD. Palladium-Catalyzed Suzuki Cross-Coupling of 2-Halo-Deazapurines with Potassium Organotrifluoroborate Salts in the Regioselective Synthesis of Imidazo[4,5-b]pyridine Analogues. Aust J Chem 2016. [DOI: 10.1071/ch15420] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In this paper, we report the use of potassium organotrifluoroborate salts as nucleophilic organoboron reagents in the Suzuki cross-coupling reactions of 2-halo deazapurines. Regio-isomeric C-2-substituted imidazo[4,5-b]pyridine analogues were synthesized by employing this protocol in good to excellent yields. Whereas aryl and heteroaryl trifluoroborates reacted readily to give the coupled products in high yields, alkyltrifluoroborates were found to be less reactive. The utilization of tetrabutylammonium acetate was found to play a substantial role in enhancing the reaction rates of the cross-coupling process. Also, a comparative study was performed between boronic acids and potassium organotrifluoroborate salts.
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Joy MN, Savitha B, Sajith AM, Bodke YD, Venkatesh T, Khader KA, Padusha MSA, Muralidharan A. A facile access for the synthesis of some C-2 substituted imidazopyrazines by utilizing the palladium catalyzed Suzuki cross-coupling reaction under microwave irradiation. CHINESE CHEM LETT 2016. [DOI: 10.1016/j.cclet.2015.08.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Sajith AM, Abdul Khader K, Joshi N, Reddy MN, Syed Ali Padusha M, Nagaswarupa H, Nibin Joy M, Bodke YD, Karuvalam RP, Banerjee R, Muralidharan A, Rajendra P. Design, synthesis and structure–activity relationship (SAR) studies of imidazo[4,5-b]pyridine derived purine isosteres and their potential as cytotoxic agents. Eur J Med Chem 2015; 89:21-31. [DOI: 10.1016/j.ejmech.2014.10.037] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 09/05/2014] [Accepted: 10/12/2014] [Indexed: 12/18/2022]
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Sajith AM, Abdul Khader KK, Muralidharan A, Ali Padusha MS, Nagaswarupa HP. A Highly Efficient Catalyst for the Suzuki Cross-coupling Reaction of 3-Chloro-5-oxadiazol-2-yl Pyridine. J Heterocycl Chem 2014. [DOI: 10.1002/jhet.2277] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- A. M. Sajith
- Post Graduate and Research Department of Chemistry, Kasargod Govt. College; Kannur University; Kasargod India
| | - K. K. Abdul Khader
- Post Graduate and Research Department of Chemistry, Jamal Mohamed College; Bharathidasan University; Tiruchirapalli India
| | - A. Muralidharan
- Post Graduate and Research Department of Chemistry, Kasargod Govt. College; Kannur University; Kasargod India
- Department of Chemistry, Nehru Arts and Science College; Kannur University; Kannur India
| | - M. S. Ali Padusha
- Post Graduate and Research Department of Chemistry, Jamal Mohamed College; Bharathidasan University; Tiruchirapalli India
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Abstract
INTRODUCTION Neuropathic pain and chronic inflammatory pain are large unmet medical needs. Over the past two decades, numerous 'pain targets' have been identified for analgesic drug discovery. Despite promising results in rodent pain models, many compounds modulating such targets lacked efficacy in clinical trials. An exception is oral EMA401, a small-molecule angiotensin II type 2 receptor (AT2R) antagonist. AREAS COVERED Herein, angiotensin II/AT2R signaling-induced hyperexcitability and abnormal sprouting of cultured dorsal root ganglion neurons, together with radioligand binding, pharmacokinetics, analgesic efficacy and mode of action of small-molecule AT2R antagonists in rodent models of peripheral neuropathic and chronic inflammatory pain, are reviewed. The findings of a successful Phase IIa clinical trial of EMA401 in patients with neuropathic pain are presented in brief. EXPERT OPINION The functional importance of angiotensin II/AT2R signaling has remained enigmatic for decades, and there are no clinically available medications that target the AT2R. However, on the basis of preclinical findings and recent clinical trial data showing that the peripherally restricted, small-molecule AT2R antagonist, EMA401, successfully alleviated neuropathic pain in a Phase II clinical trial, the AT2R is receiving considerable attention as a new therapeutic target with human validation for the relief of peripheral neuropathic and chronic inflammatory pain conditions.
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Affiliation(s)
- Maree T Smith
- The University of Queensland, Centre for Integrated Preclinical Drug Development , St Lucia Campus, Brisbane, Queensland 4072 , Australia +61 7 33652554 ; +61 7 33467391 ;
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Abdul Khader K, Sajith AM, Ali Padusha MS, Nagaswarupa H, Muralidharan A. Regioselective synthesis of C-2 substituted imidazo[4,5-b]pyridines utilizing palladium catalysed C–N bond forming reactions with enolizable heterocycles. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2014.01.114] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abdul Khader KK, Sajith AM, Syed Ali Padusha M, Nagaswarupa HP, Muralidharan A. Cycloalkenyl nonaflates as electrophilic cross-coupling substrates for palladium catalyzed C–N bond forming reactions with enolizable heterocycles under microwave enhanced conditions. NEW J CHEM 2014. [DOI: 10.1039/c3nj01355c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Joy MN, Bodke YD, Khader KKA, Ali Padusha MS, Sajith AM, Muralidharan A. A rapid and modified approach for C-7 amination and amidation of 4-methyl-7-nonafluorobutylsulfonyloxy coumarins under microwave irradiation. RSC Adv 2014. [DOI: 10.1039/c4ra01720j] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A rapid approach for the synthesis of an array of 4-methyl-7-substituted coumarins has been developed.
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Affiliation(s)
- M. Nibin Joy
- Department of P.G studies and Research in Industrial Chemistry
- Kuvempu University
- Shimoga, India-577451
| | - Yadav D. Bodke
- Department of P.G studies and Research in Industrial Chemistry
- Kuvempu University
- Shimoga, India-577451
| | - K. K. Abdul Khader
- Post Graduate and Research Department of Chemistry
- Jamal Mohamed College
- Bharathidasan University
- Tiruchirapalli, India
| | - M. Syed Ali Padusha
- Post Graduate and Research Department of Chemistry
- Jamal Mohamed College
- Bharathidasan University
- Tiruchirapalli, India
| | - Ayyiliyath M. Sajith
- Organic Chemistry Division
- School of Chemical Sciences
- Kasaragod Govt. College
- Kannur University
- Kannur, India
| | - A. Muralidharan
- Organic Chemistry Division
- School of Chemical Sciences
- Kasaragod Govt. College
- Kannur University
- Kannur, India
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Smith MT, Muralidharan A. Comment on “protective arms of the renin-angiotensin system in neurological disease”. Clin Exp Pharmacol Physiol 2013; 40:838. [DOI: 10.1111/1440-1681.12169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Maree T Smith
- Centre for Integrated Preclinical Drug Development and School of Pharmacy; The University of Queensland; Brisbane Queensland Australia
| | - Arjun Muralidharan
- Centre for Integrated Preclinical Drug Development; The University of Queensland; Brisbane Queensland Australia
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Muralidharan A, Wyse BD, Smith MT. Analgesic efficacy and mode of action of a selective small molecule angiotensin II type 2 receptor antagonist in a rat model of prostate cancer-induced bone pain. Pain Med 2013; 15:93-110. [PMID: 24433468 DOI: 10.1111/pme.12258] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE The pathobiology of prostate cancer (PCa)-induced bone pain (PCIBP) has both inflammatory and neuropathic components. Previously, we showed that small molecule angiotensin II type 2 receptor (AT2 R) antagonists with >1,000-fold selectivity over the angiotensin II type 1 receptor produced dose-dependent analgesia in a rat model of neuropathic pain. Here, we assessed the analgesic efficacy and mode of action of the AT2 R antagonist, EMA200, in a rat model of PCIBP. METHODS At 14-21 days after unilateral intratibial injection of AT3B PCa cells, rats exhibiting hindpaw hypersensitivity received single intravenous bolus doses of EMA200 (0.3-10 mg/kg) or vehicle, and analgesic efficacy was assessed. The mode of action was investigated using immunohistochemical, Western blot, and/or molecular biological methods in lumbar dorsal root ganglia (DRGs) removed from drug-naïve and EMA200-treated PCIBP rats relative to sham-control rats. RESULTS Intravenous bolus doses of EMA200 produced dose-dependent analgesia in PCIBP rats. Lumbar DRG levels of angiotensin II, nerve growth factor (NGF), tyrosine kinase A (TrkA), phospho-p38 mitogen-activated protein kinase (MAPK), and phospho-p44/p42 MAPK, but not the AT2 R, were increased significantly (P < 0.05) in PCIBP rats, c.f. the corresponding levels for sham controls. EMA200 produced analgesia in PCIBP rats by reducing elevated angiotensin II levels in the lumbar DRGs to attenuate augmented angiotensin II/AT2 R signaling. This in turn reduced augmented NGF/TrkA signaling in the lumbar DRGs. The net result was inhibition of p38 MAPK and p44/p42 MAPK activation. CONCLUSION Small molecule AT2 R antagonists are worthy of further investigation as novel analgesics for relief of intractable PCIBP and other pain types where hyperalgesia worsens symptoms.
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Affiliation(s)
- Arjun Muralidharan
- Centre for Integrated Preclinical Drug Development, The University of Queensland, Brisbane, Queensland, Australia; The School of Pharmacy, The University of Queensland, Brisbane, Queensland, Australia
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Smith MT, Woodruff TM, Wyse BD, Muralidharan A, Walther T. A Small Molecule Angiotensin II Type 2 Receptor (AT2R) Antagonist Produces Analgesia in a Rat Model of Neuropathic Pain by Inhibition of p38 Mitogen-Activated Protein Kinase (MAPK) and p44/p42 MAPK Activation in the Dorsal Root Ganglia. Pain Med 2013; 14:1557-68. [DOI: 10.1111/pme.12157] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Abstract
Pain severity ratings and the analgesic dosing requirements of patients with apparently similar pain conditions may differ considerably between individuals. Contributing factors include those of genetic and environmental origin with epigenetic mechanisms that enable dynamic gene-environment interaction, more recently implicated in pain modulation. Insight into genetic factors underpinning inter-patient variability in pain sensitivity has come from rodent heritability studies as well as familial aggregation and twin studies in humans. Indeed, more than 350 candidate pain genes have been identified as potentially contributing to heritable differences in pain sensitivity. A large number of genetic association studies conducted in patients with a variety of clinical pain types or in humans exposed to experimentally induced pain stimuli in the laboratory setting, have examined the impact of single-nucleotide polymorphisms in various target genes on pain sensitivity and/or analgesic dosing requirements. However, the findings of such studies have generally failed to replicate or have been only partially replicated by independent investigators. Deficiencies in study conduct including use of small sample size, inappropriate statistical methods and inadequate attention to the possibility that between-study differences in environmental factors may alter pain phenotypes through epigenetic mechanisms, have been identified as being significant.
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Affiliation(s)
- M T Smith
- Centre for Integrated Preclinical Drug Development, The University of Queensland, Brisbane, Queensland, Australia.
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Sajith AM, Muralidharan A. Microwave enhanced Suzuki coupling: a diversity-oriented approach to the synthesis of highly functionalised 3-substituted-2-aryl/heteroaryl imidazo[4,5-b]pyridines. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2011.12.051] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
OBJECTIVES In the clinical setting, there is marked intersubject variability in the intensity of pain reported by patients with apparently similar pain states, as well as widely differing analgesic dosing requirements between individuals to produce satisfactory pain relief with tolerable side-effects. Genetic and environmental factors as well as their interaction are implicated, and these are discussed in this review. KEY FINDINGS Pioneering work undertaken in mice more than a decade ago, showed a strong genetic contribution to levels of nociception/hypersensitivity as well as levels of antinociception produced by commonly available analgesic agents. To date more than 300 candidate 'pain' genes have been identified as potentially contributing to heritable differences in pain sensitivity and analgesic responsiveness in animals and humans, with this information available in a publicly accessible database http://www.jbldesign.com/jmogil/enter.html. Since then, many genetic association studies have been conducted in humans to investigate the possibility that single nucleotide polymorphisms (SNPs) in an individual gene may explain drug inefficacy or excessive toxicity experienced by a small subset of the whole population who have the rare allele for a particular SNP. SUMMARY Despite the fact that SNPs in more than 20 genes that affect pain sensitivity or contribute to interindividual variability in responses to analgesic medications have been identified in the human genome, much of the data is conflicting. Apart from deficiencies in the design and conduct of human genetic association studies, recent research from other fields has implicated epigenetic mechanisms that facilitate dynamic gene-environment communication, as a possible explanation.
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Affiliation(s)
- Arjun Muralidharan
- The University of Queensland, Centre for Integrated Preclinical Drug Development and School of Pharmacy, Steele Building, St Lucia Campus, Brisbane, Queensland, Australia
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Abstract
Movement-assist devices such as neuromuscular stimulation systems can be used to generate movements in people with chronic hand paralysis due to stroke. If detectable, motor planning activity in the cortex could be used in real time to trigger a movement-assist device and restore a person's ability to perform many of the activities of daily living. Additionally, re-coupling motor planning in the cortex with assisted movement generation in the periphery may provide an even greater benefit-strengthening relevant synaptic connections over time to promote natural motor recovery. This study examined the potential for using electroencephalograms (EEGs) as a means of rapidly detecting the intent to open the hand during movement planning in individuals with moderate chronic hand paralysis following a subcortical ischemic stroke. On average, attempts to open the hand could be detected from EEGs approximately 100-500 ms prior to the first signs of movement onset. This earlier detection would minimize device activation delays and allow for tighter coupling between initial formation of the motor plan in the cortex and augmentation of that plan in the periphery by a movement-assist device. This tight temporal coupling may be important or even essential for strengthening synaptic connections and enhancing natural motor recovery.
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Affiliation(s)
- A Muralidharan
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
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Fun HK, Chantrapromma S, Sujith KV, Patil PS, Kalluraya B, Muralidharan A, Dharmaprakash SM. 4-[( E)-2,6-Dichlorobenzylideneamino]-3-{1-[4-(2-methylpropyl)phenyl]ethyl}-1 H-1,2,4-triazole-5(4 H)-thione. Acta Crystallogr Sect E Struct Rep Online 2008; 64:o1503-4. [PMID: 21203213 PMCID: PMC2962131 DOI: 10.1107/s1600536808021272] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Accepted: 07/09/2008] [Indexed: 11/10/2022]
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Fun HK, Jebas SR, Patil PS, Kalluraya B, Muralidharan A. 4-(4-Bromobenzylideneamino)-3-{1-[4-(2-methylpropyl)phenyl]ethyl}-1-(morpholinomethyl)-1 H-1,2,4-triazole-5(4 H)-thione. Acta Crystallogr Sect E Struct Rep Online 2008; 64:o1570-1. [PMID: 21203272 PMCID: PMC2962191 DOI: 10.1107/s160053680802254x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2008] [Accepted: 07/18/2008] [Indexed: 11/10/2022]
Abstract
There are two molecules (A and B) in the asymmetric unit of the title compound, C26H32BrN5OS, with almost identical geometry. The morpholine ring adopts the usual chair conformation in both molecules. The triazole ring forms dihedral angles of 4.84 (6) and 74.19 (6)°, respectively, with the bromophenyl and isobutylbenzene rings in molecule A, and angles of 16.68 (7) and 87.29 (6)°, respectively, in molecule B. Intramolecular C—H⋯S hydrogen bonds generate S(5) and S(6) ring motifs in both independent molecules. The crystal structure is stabilized by C—H⋯N, C—H⋯Br and C—H⋯O hydrogen-bonding interactions, together with C—H⋯π interactions.
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Fun HK, Jebas SR, Sujith KV, Patil PS, Kalluraya B, Muralidharan A, Dharmaprakash SM. 4-[(E)-4-Bromo-benzyl-ideneamino]-3-methyl-1H-1,2,4-triazole-5(4H)-thione. Acta Crystallogr Sect E Struct Rep Online 2008; 64:o1509. [PMID: 21203218 PMCID: PMC2962136 DOI: 10.1107/s1600536808021636] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Accepted: 07/11/2008] [Indexed: 05/30/2023]
Abstract
In the title mol-ecule, C(10)H(9)BrN(4)S, the dihedral angle between the triazole and benzene rings is 12.32 (19)°. An intra-molecular C-H⋯S hydrogen bond generates an S(6) ring motif. In the crystal packing, centrosymmetrically related mol-ecules are linked into a dimer by N-H⋯S hydrogen bonds, and the dimers are linked into a chain running along [11] by Br⋯N short contacts [3.187 (3) Å]. The crystal packing is further strengthened by π-π inter-actions involving the triazole ring [centroid-centroid distance = 3.322 (2) Å].
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Affiliation(s)
- Hoong-Kun Fun
- X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
| | - Samuel Robinson Jebas
- X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
| | - K. V. Sujith
- Department of Studies in Chemistry, Mangalore University, Mangalagangotri, Mangalore 574 199, India
| | - P. S. Patil
- Department of Studies in Physics, Mangalore University, Mangalagangotri, Mangalore 574 199, India
| | - B. Kalluraya
- Department of Studies in Chemistry, Mangalore University, Mangalagangotri, Mangalore 574 199, India
| | - A. Muralidharan
- Department of Chemistry, Nehru Arts and Science College, Kanhangad, Kerala 671 328, India
| | - S. M. Dharmaprakash
- Department of Studies in Physics, Mangalore University, Mangalagangotri, Mangalore 574 199, India
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El Sayed KA, Laphookhieo S, Baraka HN, Yousaf M, Hebert A, Bagaley D, Rainey FA, Muralidharan A, Thomas S, Shah GV. Biocatalytic and semisynthetic optimization of the anti-invasive tobacco (1S,2E,4R,6R,7E,11E)-2,7,11-cembratriene-4,6-diol. Bioorg Med Chem 2008; 16:2886-93. [PMID: 18222089 DOI: 10.1016/j.bmc.2007.12.056] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2007] [Revised: 12/27/2007] [Accepted: 12/28/2007] [Indexed: 11/24/2022]
Abstract
Tobacco cembranoids were reported to inhibit tumorigenesis. Biocatalysis of (1S,2E,4R,6R,7E,11E)-2,7,11-cembratriene-4,6-diol (1) using the symbiotic Bacillus sp. NC5, Bacillus sp. NK8, and Bacillus sp. NK7, isolated from the Red Sea sponge Negombata magnifica, afforded two new and four known hydroxylated metabolites 3-8. The use of symbiotic marine bacteria as biocatalysts for bioactive natural product scaffolds is very rare. Cembranoid 1 carbamate analogs 9-11 were prepared by its reaction with corresponding isocyanates. Cembranoid 1 and its bioconversion and carabamate products show anti-invasive activity against the human highly metastatic prostate PC-3M cancer cell line at 10-50 nM doses in Matrigel assay.
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Affiliation(s)
- Khalid A El Sayed
- Department of Basic Pharmaceutical Sciences, College of Pharmacy, University of Louisiana at Monroe, 700 University Avenue, Monroe, LA 71209, USA.
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Sayed KAE, Khanfar MA, Shallal HM, Muralidharan A, Awate B, Youssef DTA, Liu Y, Zhou YD, Nagle DG, Shah G. Latrunculin A and its C-17-O-carbamates inhibit prostate tumor cell invasion and HIF-1 activation in breast tumor cells. J Nat Prod 2008; 71:396-402. [PMID: 18298079 PMCID: PMC2930178 DOI: 10.1021/np070587w] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The marine-derived macrolides latrunculins A ( 1) and B, from the Red Sea sponge Negombata magnifica, have been found to reversibly bind actin monomers, forming a 1:1 complex with G-actin and disrupting its polymerization. The microfilament protein actin is responsible for several essential functions within the cell such as cytokinesis and cell migration. One of the main binding pharmacophores of 1 to G-actin was identified as the C-17 lactol hydroxyl moiety that binds arginine 210 NH. Latrunculin A-17- O-carbamates 2- 6 were prepared by reaction with the corresponding isocyanates. Latrunculin A ( 1) and carbamates 4- 6 displayed potent anti-invasive activity against the human highly metastatic human prostate cancer PC-3M cells in a Matrigel assay at a concentration range of 50 nM to 1 microM. Latrunculin A ( 1, 500 nM) decreased the disaggregation and cell migration of PC-3M-CT+ spheroids by 3-fold. Carbamates 4 and 5 were 2.5- and 5-fold more active than 1, respectively, in this assay with less actin binding affinity. Latrunculin A ( 1, IC 50 6.7 microM) and its 17- O-[ N-(benzyl)carbamate ( 6, IC 50 29 microM) suppress hypoxia-induced HIF-1 activation in T47D breast tumor cells.
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Affiliation(s)
- Khalid A El Sayed
- Department of Basic Pharmaceutical Sciences, University of Louisana, Monroe, Louisana 71209, USA.
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Thomas S, Muralidharan A, Shah G. Knock-down of calcitonin receptor expression induces apoptosis and growth arrest of prostate cancer cells. Int J Oncol 2007. [DOI: 10.3892/ijo.31.6.1425] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Thomas S, Muralidharan A, Shah GV. Knock-down of calcitonin receptor expression induces apoptosis and growth arrest of prostate cancer cells. Int J Oncol 2007; 31:1425-1437. [PMID: 17982669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023] Open
Abstract
Calcitonin (CT) and its receptor (CTR) are expressed only in basal epithelium of benign prostate and in whole epithelium of malignant prostates. Also, CT and CTR mRNA levels in prostate cancers increase with an increase in tumor grade. We tested the role of the CT/CTR autocrine axis on the tumorigenicity of prostate cancer cells. We enforced the expression of CTR in CT-positive/CTR-deficient PC-3 cells. In contrast, we knocked down CTR expression in CT/CTR-positive PC-3M cells. The effect of CTR modulation on the oncogenicity was evaluated by the rate of cell proliferation, invasion, colony formation and in vivo growth in nude mice. Up-regulation of CTR in PC-3 cells and its down-regulation in PC-3M cells significantly altered their tumorigenicity. Intratumorally administered CTR RNAi in preexisting PC-3M xenografts markedly attenuated their further growth. This treatment also led to a remarkable decrease in endothelial cell populations in the tumors and increase in apoptotic, PCNA-negative cell populations. Tumors receiving CTR RNAi treatment displayed markedly lower levels of urokinase-type plasminogen activator, phospho-Akt and survivin, suggesting CTR activates uPA-uPAR axis and PI-3-kinase-Akt-survivin pathway. These results suggest an important role for CT-CTR autocrine axis in the progression of localized prostate tumor to a metastatic phenotype, and offer a potential therapeutic option for invasive cancers.
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Affiliation(s)
- Shibu Thomas
- Pharmacology, University of Louisiana School of Pharmacy, College of Health Sciences, Monroe, LA 71209, USA
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