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Chakrabarti S, Klich JD, Khallaf MA, Hulme AJ, Sánchez-Carranza O, Baran ZM, Rossi A, Huang ATL, Pohl T, Fleischer R, Fürst C, Hammes A, Bégay V, Hörnberg H, Finol-Urdaneta RK, Poole K, Dottori M, Lewin GR. Touch sensation requires the mechanically gated ion channel ELKIN1. Science 2024; 383:992-998. [PMID: 38422143 DOI: 10.1126/science.adl0495] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 01/26/2024] [Indexed: 03/02/2024]
Abstract
Touch perception is enabled by mechanically activated ion channels, the opening of which excites cutaneous sensory endings to initiate sensation. In this study, we identify ELKIN1 as an ion channel likely gated by mechanical force, necessary for normal touch sensitivity in mice. Touch insensitivity in Elkin1-/- mice was caused by a loss of mechanically activated currents (MA currents) in around half of all sensory neurons activated by light touch (low-threshold mechanoreceptors). Reintroduction of Elkin1 into sensory neurons from Elkin1-/- mice restored MA currents. Additionally, small interfering RNA-mediated knockdown of ELKIN1 from induced human sensory neurons substantially reduced indentation-induced MA currents, supporting a conserved role for ELKIN1 in human touch. Our data identify ELKIN1 as a core component of touch transduction in mice and potentially in humans.
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Affiliation(s)
- Sampurna Chakrabarti
- Molecular Physiology of Somatic Sensation Laboratory, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin-Buch, Germany
| | - Jasmin D Klich
- Molecular Physiology of Somatic Sensation Laboratory, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin-Buch, Germany
| | - Mohammed A Khallaf
- Molecular Physiology of Somatic Sensation Laboratory, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin-Buch, Germany
- Department of Zoology and Entomology, Faculty of Science, Assiut University, Assiut 71516, Egypt
| | - Amy J Hulme
- School of Medical, Indigenous and Health Sciences, Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Oscar Sánchez-Carranza
- Molecular Physiology of Somatic Sensation Laboratory, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin-Buch, Germany
| | - Zuzanna M Baran
- Molecular Physiology of Somatic Sensation Laboratory, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin-Buch, Germany
- Molecular and Cellular Basis of Behavior, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin-Buch, Germany
| | - Alice Rossi
- Molecular Physiology of Somatic Sensation Laboratory, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin-Buch, Germany
| | - Angela Tzu-Lun Huang
- Molecular Physiology of Somatic Sensation Laboratory, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin-Buch, Germany
| | - Tobias Pohl
- Molecular and Cellular Basis of Behavior, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin-Buch, Germany
| | - Raluca Fleischer
- Molecular Physiology of Somatic Sensation Laboratory, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin-Buch, Germany
| | - Carina Fürst
- Molecular Physiology of Somatic Sensation Laboratory, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin-Buch, Germany
- Molecular Pathways in Cortical Development, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin-Buch, Germany
| | - Annette Hammes
- Molecular Pathways in Cortical Development, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin-Buch, Germany
| | - Valérie Bégay
- Molecular Physiology of Somatic Sensation Laboratory, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin-Buch, Germany
| | - Hanna Hörnberg
- Molecular and Cellular Basis of Behavior, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin-Buch, Germany
- NeuroCure Cluster of Excellence, Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - Rocio K Finol-Urdaneta
- School of Medical, Indigenous and Health Sciences, Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Kate Poole
- School of Biomedical Sciences, Faculty of Medicine & Health, University of New South Wales, Sydney, NSW 2052, Australia
| | - Mirella Dottori
- School of Medical, Indigenous and Health Sciences, Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Gary R Lewin
- Molecular Physiology of Somatic Sensation Laboratory, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin-Buch, Germany
- Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
- German Center for Mental Health (DZPG), partner site Berlin, 10117 Berlin, Germany
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2
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Patkunarajah A, Stear JH, Moroni M, Schroeter L, Blaszkiewicz J, Tearle JLE, Cox CD, Fürst C, Sánchez-Carranza O, Ocaña Fernández MDÁ, Fleischer R, Eravci M, Weise C, Martinac B, Biro M, Lewin GR, Poole K. TMEM87a/Elkin1, a component of a novel mechanoelectrical transduction pathway, modulates melanoma adhesion and migration. eLife 2020; 9:53308. [PMID: 32228863 PMCID: PMC7173973 DOI: 10.7554/elife.53308] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [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: 11/04/2019] [Accepted: 03/28/2020] [Indexed: 01/04/2023] Open
Abstract
Mechanoelectrical transduction is a cellular signalling pathway where physical stimuli are converted into electro-chemical signals by mechanically activated ion channels. We describe here the presence of mechanically activated currents in melanoma cells that are dependent on TMEM87a, which we have renamed Elkin1. Heterologous expression of this protein in PIEZO1-deficient cells, that exhibit no baseline mechanosensitivity, is sufficient to reconstitute mechanically activated currents. Melanoma cells lacking functional Elkin1 exhibit defective mechanoelectrical transduction, decreased motility and increased dissociation from organotypic spheroids. By analysing cell adhesion properties, we demonstrate that Elkin1 deletion is associated with increased cell-substrate adhesion and decreased homotypic cell-cell adhesion strength. We therefore conclude that Elkin1 supports a PIEZO1-independent mechanoelectrical transduction pathway and modulates cellular adhesions and regulates melanoma cell migration and cell-cell interactions. When cells receive signals about their surrounding environment, this initiates a chain of signals which generate a response. Some of these signalling pathways allow cells to sense physical and mechanical forces via a process called mechanotransduction. There are different types of mechanotransduction. In one pathway, mechanical forces open up specialized channels on the cell surface which allow charged particles to move across the membrane and create an electrical current. Mechanoelectrical transduction plays an important role in the spread of cancer: as cancer cells move away from a tumour they use these signalling pathways to find their way between cells and move into other parts of the body. Understanding these pathways could reveal ways to stop cancer from spreading, making it easier to treat. However, it remains unclear which molecules regulate mechanoelectrical transduction in cancer cells. Now, Patkunarajah, Stear et al. have studied whether mechanoelectrical transduction is involved in the migration of skin cancer cells. To study mechanoelectrical transduction, a fine mechanical input was applied to the skin cancer cells whilst measuring the flow of charged molecules moving across the membrane. This experiment revealed that a previously unknown protein named Elkin1 is required to convert mechanical forces into electrical currents. Deleting this newly found protein caused skin cancer cells to move more slowly and dissociate more easily from tumour-like clusters of cells. These findings suggest that Elkin1 is part of a newly identified mechanotransduction pathway that allows cells to sense mechanical forces from their surrounding environment. More work is needed to determine what role Elkin1 plays in mechanoelectrical transduction and whether other proteins are also involved. This could lead to new approaches that prevent cancer cells from dissociating from tumours and spreading to other body parts.
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Affiliation(s)
- Amrutha Patkunarajah
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia.,Cellular and Systems Physiology, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Jeffrey H Stear
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia.,Max Delbrück Center for Molecular Medicine, Berlin-Buch, Germany
| | - Mirko Moroni
- Max Delbrück Center for Molecular Medicine, Berlin-Buch, Germany
| | - Lioba Schroeter
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia.,Cellular and Systems Physiology, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | | | - Jacqueline LE Tearle
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Charles D Cox
- Victor Chang Cardiac Research Institute, Sydney, Australia.,St Vincent's Clinical School, University of New South Wales, Darlinghurst, Australia
| | - Carina Fürst
- Max Delbrück Center for Molecular Medicine, Berlin-Buch, Germany
| | | | | | - Raluca Fleischer
- Max Delbrück Center for Molecular Medicine, Berlin-Buch, Germany
| | - Murat Eravci
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Berlin, Germany
| | - Christoph Weise
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Berlin, Germany
| | - Boris Martinac
- Victor Chang Cardiac Research Institute, Sydney, Australia.,St Vincent's Clinical School, University of New South Wales, Darlinghurst, Australia
| | - Maté Biro
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia.,ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, Australia
| | - Gary R Lewin
- Max Delbrück Center for Molecular Medicine, Berlin-Buch, Germany
| | - Kate Poole
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia.,Cellular and Systems Physiology, School of Medical Sciences, University of New South Wales, Sydney, Australia.,Max Delbrück Center for Molecular Medicine, Berlin-Buch, Germany.,ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, Australia
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3
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Baker D, Osborn D, Fleischer R, Celermajer D, Collins F, Cordina R. 658 Early Experience of a Combined Adult Congenital Heart Disease and Genetic Clinic. Heart Lung Circ 2020. [DOI: 10.1016/j.hlc.2020.09.665] [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: 12/01/2022]
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4
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Moroni M, Servin-Vences MR, Fleischer R, Sánchez-Carranza O, Lewin GR. Voltage gating of mechanosensitive PIEZO channels. Nat Commun 2018; 9:1096. [PMID: 29545531 PMCID: PMC5854696 DOI: 10.1038/s41467-018-03502-7] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [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] [Received: 08/17/2017] [Accepted: 02/19/2018] [Indexed: 12/13/2022] Open
Abstract
Mechanosensitive PIEZO ion channels are evolutionarily conserved proteins whose presence is critical for normal physiology in multicellular organisms. Here we show that, in addition to mechanical stimuli, PIEZO channels are also powerfully modulated by voltage and can even switch to a purely voltage-gated mode. Mutations that cause human diseases, such as xerocytosis, profoundly shift voltage sensitivity of PIEZO1 channels toward the resting membrane potential and strongly promote voltage gating. Voltage modulation may be explained by the presence of an inactivation gate in the pore, the opening of which is promoted by outward permeation. Older invertebrate (fly) and vertebrate (fish) PIEZO proteins are also voltage sensitive, but voltage gating is a much more prominent feature of these older channels. We propose that the voltage sensitivity of PIEZO channels is a deep property co-opted to add a regulatory mechanism for PIEZO activation in widely different cellular contexts. PIEZO proteins form mechanosensitive ion channels. Here the authors present electrophysiological measurements that show that PIEZO channels are also modulated by voltage and can switch to a purely voltage gated mode, which is an evolutionary conserved property of this channel family.
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Affiliation(s)
- Mirko Moroni
- Department of Neuroscience, Max-Delbrück Center for Molecular Medicine, Robert-Rössle Straße 10, D-13092, Berlin, Germany.
| | - M Rocio Servin-Vences
- Department of Neuroscience, Max-Delbrück Center for Molecular Medicine, Robert-Rössle Straße 10, D-13092, Berlin, Germany
| | - Raluca Fleischer
- Department of Neuroscience, Max-Delbrück Center for Molecular Medicine, Robert-Rössle Straße 10, D-13092, Berlin, Germany
| | - Oscar Sánchez-Carranza
- Department of Neuroscience, Max-Delbrück Center for Molecular Medicine, Robert-Rössle Straße 10, D-13092, Berlin, Germany
| | - Gary R Lewin
- Department of Neuroscience, Max-Delbrück Center for Molecular Medicine, Robert-Rössle Straße 10, D-13092, Berlin, Germany. .,Excellence Cluster Neurocure, Charité Universitätsmedizin, 10117, Berlin, Germany.
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5
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Clark J, Alves S, Gundlah C, Rocha B, Birzin E, Cai SJ, Flick R, Hayes E, Ho K, Warrier S, Pai L, Yudkovitz J, Fleischer R, Colwell L, Li S, Wilkinson H, Schaeffer J, Wilkening R, Mattingly E, Hammond M, Rohrer S. Selective estrogen receptor-beta (SERM-beta) compounds modulate raphe nuclei tryptophan hydroxylase-1 (TPH-1) mRNA expression and cause antidepressant-like effects in the forced swim test. Neuropharmacology 2012; 63:1051-63. [DOI: 10.1016/j.neuropharm.2012.07.004] [Citation(s) in RCA: 23] [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] [Received: 03/17/2012] [Revised: 06/08/2012] [Accepted: 07/01/2012] [Indexed: 10/28/2022]
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7
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8
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Shearman LP, Rosko KM, Fleischer R, Wang J, Xu S, Tong XS, Rocha BA. Antidepressant-like and anorectic effects of the cannabinoid CB1 receptor inverse agonist AM251 in mice. Behav Pharmacol 2003; 14:573-82. [PMID: 14665974 DOI: 10.1097/00008877-200312000-00001] [Citation(s) in RCA: 143] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Psychopathological disorders, and depression in particular, are strongly linked to eating attitude in obese patients. The identification of cannabinoid CB1 receptors (CB1Rs) in areas of the central nervous system (CNS) that have been implicated in regulation of mood and food intake suggests that these receptors may mediate such a behavioral link. The goal of this study was to evaluate CB1R modulation of antidepressant-like effects and food intake. For this purpose, 129/SVE and C57BL/6 male mice were acutely dosed intraperitoneally (i.p.) with the CB1R inverse agonist AM251 (3-30 mg/kg) and tested, respectively, in the tail-suspension test (TST) and in the forced-swim test (FST), which have been used widely as tests sensitive to antidepressant compounds. Like the antidepressant desipramine (DMI, 16 mg/kg), AM251 significantly reduced immobility at 10 mg/kg in the TST and at 1 and 10 mg/kg in the FST. Such a decrease of immobility was not accompanied by an increase in motor activity in the open field, suggesting that occupancy of CB1R by AM251 induced antidepressant-like effects. This was supported by two additional experiments. First, the co-administration of the CB1R agonist CP55940, at a dose that did not induce motor impairment or profound hypothermia (0.01 mg/kg), reversed effects of AM251 in the TST. Secondly, effects of AM251 in the FST were absent in CB1R knockout (KO) mice. In addition to an antidepressant-like effect, AM251 reduced fasting-induced hyperphagia over a comparable dose range. Taken together, these data suggest that regulation of mood and food intake might be obtained through inverse agonism of CB1R.
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Affiliation(s)
- L P Shearman
- Department of Pharmacology, Merck Research Laboratories, Rahway, NJ 07065, USA
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9
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Hagedorn M, Lance SL, Fonseca DM, Kleinhans FW, Artimov D, Fleischer R, Hoque ATMS, Hamilton MB, Pukazhenthi BS. Altering fish embryos with aquaporin-3: an essential step toward successful cryopreservation. Biol Reprod 2002; 67:961-6. [PMID: 12193408 DOI: 10.1095/biolreprod.101.002915] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [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] [Indexed: 11/01/2022] Open
Abstract
Fish populations are globally threatened by overharvesting and habitat degradation. The ability to bank fish embryos by cryopreservation could be crucial for preserving species diversity, for aquaculture (allowing circannual fish farming), and for managing fish models used in human biomedical research. However, no nonmammalian embryo has ever been successfully cryopreserved. For fish, low membrane permeability prevents cryoprotectants from entering the yolk to prevent cryodamage. Here, we present evidence of a membrane mechanism hindering cryopreservation of fish and propose a novel solution to this obstacle. Zebrafish (Danio rerio) embryos have rectifying membranes that allow water to leave but not to reenter readily. This feature may be an evolutionary trait that allows freshwater embryos to grow in hypoosmotic environments without osmoregulatory organs. However, this trait may also prevent successful fish embryo cryopreservation because both water and cryoprotectants must move into and out of cells. As a solution, we injected zebrafish embryos with mRNA for the aquaporin-3 water channel protein and demonstrated increased membrane permeability to water and to a cryoprotectant. Modeling indicates that sufficient cryoprotectant enters aquaporin-3-expressing zebrafish embryos to allow cryopreservation.
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Affiliation(s)
- M Hagedorn
- Department of Reproductive Science, Smithsonian Institution, National Zoological Park and Conservation and Research Center, Washington, District of Columbia 20008, USA.
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10
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Shanafelt AB, Lin Y, Shanafelt MC, Forte CP, Dubois-Stringfellow N, Carter C, Gibbons JA, Cheng SL, Delaria KA, Fleischer R, Greve JM, Gundel R, Harris K, Kelly R, Koh B, Li Y, Lantz L, Mak P, Neyer L, Plym MJ, Roczniak S, Serban D, Thrift J, Tsuchiyama L, Wetzel M, Wong M, Zolotorev A. A T-cell-selective interleukin 2 mutein exhibits potent antitumor activity and is well tolerated in vivo. Nat Biotechnol 2000; 18:1197-202. [PMID: 11062441 DOI: 10.1038/81199] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Human interleukin 2 (IL-2; Proleukin) is an approved therapeutic for advanced-stage metastatic cancer; however, its use is restricted because of severe systemic toxicity. Its function as a central mediator of T-cell activation may contribute to its efficacy for cancer therapy. However, activation of natural killer (NK) cells by therapeutically administered IL-2 may mediate toxicity. Here we have used targeted mutagenesis of human IL-2 to generate a mutein with approximately 3,000-fold in vitro selectivity for T cells over NK cells relative to wild-type IL-2. We compared the variant, termed BAY 50-4798, with human IL-2 (Proleukin) in a therapeutic dosing regimen in chimpanzees, and found that although the T-cell mobilization and activation properties of BAY 50-4798 were comparable to human IL-2, BAY 50-4798 was better tolerated in the chimpanzee. BAY 50-4798 was also shown to inhibit metastasis in a mouse tumor model. These results indicate that BAY 50-4798 may exhibit a greater therapeutic index than IL-2 in humans in the treatment of cancer and AIDS.
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Affiliation(s)
- A B Shanafelt
- Research, Biotechnology, Bayer Corporation, Pharmaceutical Division, 800 Dwight Way, Berkeley, CA 94701, USA.
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11
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Goldsworthy S, Francis J, Boness D, Fleischer R. Variation in the mitochondrial control region in the Juan Fernández fur seal (Arctocephalus philippii). J Hered 2000; 91:371-7. [PMID: 10994703 DOI: 10.1093/jhered/91.5.371] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The Juan Fernandez fur seal (Arctocephalus philippii was allegedly extremely abundant, numbering as many as 4 million prior to sealing which continued from the late 17th to the late 19th century. By the end of the sealing era the species was thought to be extinct until they were rediscovered at Alejandro Selkirk Island in 1965. Historic records would suggest that the species underwent a substantial population bottleneck as a result of commercial sealing, and from population genetic theory we predicted that the genetic variability in the species would be low. We compared the mtDNA control region sequence from 28 Juan Fernandez fur seals from two islands in the Juan Fernandez Archipelago (Chile). Contrary to expectation, we found that variation in the Juan Fernandez fur seals is not greatly reduced in comparison to other pinniped taxa, especially given the apparent severity of the bottleneck they underwent. We also determined minor, but significantly different haplotype frequencies among the populations on the two islands (Alejandro Selkirk and Robinson Crusoe Islands), but no difference in their levels of variability. Such differences may have arisen stochastically via a recent founder event from Alejandro Selkirk to Robinson Crusoe Island or subsequent genetic drift.
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Affiliation(s)
- S Goldsworthy
- National Zoological Park, Smithsonian Institution, Washington, DC 20008, USA
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12
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Hilgeroth A, Fleischer R, Wiese M, Heinemann FW. Comparison of azacyclic urea A-98881 as HIV-1 protease inhibitor with cage dimeric N-benzyl 4-(4-methoxyphenyl)-1,4-dihydropyridine as representative of a novel class of HIV-1 protease inhibitors: a molecular modeling study. J Comput Aided Mol Des 1999; 13:233-42. [PMID: 10216831 DOI: 10.1023/a:1008038608460] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The functional groups of cage dimeric N-alkyl substituted 3,5-bis(hydroxymethyl)-4-(4-methoxyphenyl)-1,4-dihydropyridines are similar to those of cyclic and azacyclic ureas that are potent inhibitors of HIV-1 protease of the dihydroxyethylene- and hydroxyethylene type, respectively. In the following study the conformity of common functional groups is investigated concerning their orientation in space as well as in the enzyme HIV-1 protease. Starting from X-ray crystal data of the centrosymmetric cage dimeric N-benzyl derivative with ester groups, the derivative with hydroxymethylene groups was built and a systematic conformational search was performed for the conformationally important torsion angles considering electrostatic and van der Waals interactions. From the huge number of conformations those comprising centrosymmetrical and C2-symmetrical energy minima were selected and minimized. The three remaining conformers were fitted to the azacyclic urea A-98881 selected from the HIV-1 protease enzyme-inhibitor complex using the centroids of the corresponding aromatic residues and additionally by the field fit option of the Advanced CoMFA module of SYBYL. Interestingly, the energetically most favourable one, which, additionally, possesses C2-symmetry like the active site cavity of HIV-1 protease, showed the best fit. Comparing the electrostatic potential (EP) of the latter with the EP of A-98881 the aromatic residues show excellent accordance. Slight differences in the extent of the EP were found in the areas of the hydroxymethylene groups of the cage dimer and the single hydroxy group as well as the urea carbonyl group of A-98881, respectively. In order to compare the binding possibilities to the enzyme HIV-1 protease for the cage dimer and A-98881, their interaction fields with certain probes (CH3 for alkyl, NHamide, and carbonyl, O- of COO-), representing the decisive functional groups of the active site, have been calculated using GRID and projected into the enzyme placing the structures according to the position of A-98881 in the enzyme-inhibitor complex. The strongest calculated fields of the O- probe were found near Asp 25 for both structures. Another respective conformity consists in the overlap of the fields for the NHamide probe near Ile 50 and 50' for the investigated cage dimer and A-98881.
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Affiliation(s)
- A Hilgeroth
- Department of Pharmacy, Martin-Luther-University Halle-Wittenberg, Germany.
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13
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Abstract
Endangered San Joaquin kit foxes Vulpes macrotis mutica can be sympatrically distributed with as many as four other canids: red fox, gray fox, coyote and domestic dog. Canid scats are often found during routine fieldwork, but cannot be reliably identified to species. To detect and study the endangered kit fox, we developed mitochondrial DNA markers that can be amplified from small amounts of DNA extracted from scats. We amplified a 412-bp fragment of the mitochondrial cytochrome-b gene from scat samples and digested it with three restriction enzymes. The resulting restriction profiles discriminated among all five canid species and correctly identified 10 'unknown' fox scats to species in blind tests. We have applied our technique to identify canids species for an environmental management study and a conservation study. We envision that our protocol, and similar ones developed for other endangered species will be greatly used for conservation management in the future.
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Affiliation(s)
- E Paxinos
- Department of Zoological Research, Smithsonian Institution, Washington, DC 20008, USA.
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Sanders JE, Buckner CD, Thomas ED, Fleischer R, Sullivan KM, Appelbaum FA, Storb R. Allogeneic marrow transplantation for children with juvenile chronic myelogenous leukemia. Blood 1988; 71:1144-6. [PMID: 3281722] [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: 01/05/2023] Open
Abstract
Fourteen children between the ages of 2 and 5 years with juvenile chronic myelogenous leukemia were given cyclophosphamide, total-body irradiation, and marrow transplants. Unmodified marrow was given to six patients who received marrow from HLA-identical siblings and eight patients who received marrow from family members HLA identical for one haplotype but mismatched for one to three loci on the nonshared haplotype. Five patients died of transplant-related complications, and three relapsed at 48, 81, and 1,670 days posttransplant and died of leukemia. Six patients survive in continuous remission from 0.5 to 11.5 years posttransplant.
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Affiliation(s)
- J E Sanders
- Fred Hutchinson Cancer Reasearch Center, Division of Clinical Research, Seattle, WA 98104
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15
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Schlegel W, Heinze A, Fleischer R, Wähner M. [Effect of PMSG/HCG combinations on ovaries and uteri of gilts used for stimulation of estrous cycle within the framework of puberty induction to advance the 1st insemination date]. Arch Exp Veterinarmed 1983; 37:899-904. [PMID: 6686926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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16
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Kao KJ, Fleischer R, Bradford WD, Woodard BH. Multiple congenital septal atresias of the intestine: histomorphologic and pathogenetic implications. Pediatr Pathol 1983; 1:443-8. [PMID: 6687294 DOI: 10.3109/15513818309025876] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Congenital atresias of the gastrointestinal tract are usually single and divided into three forms on a morphologic basis. The septal or diaphragmatic type (type I) is the least common. We report an infant with multiple type I atresias involving both the small and large intestine and describe the unique histologic features of the septa: fragmentation of muscularis mucosa, multiple septal cysts lined by columnar epithelium, circular and longitudinal muscular layers, and absence of inflammation. This infant had a sibling who died with multiple intestinal atresias of the septal type. The histologic features suggest that type I gastrointestinal atresias may be due to failure of complete recanalization rather than result from healing of vascular of inflammatory events.
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Fleischer R. [Capacity of recovery of the irradiated root tissue of vicia faba (author's transl)]. Strahlentherapie 1981; 157:827-32. [PMID: 7330912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Penzoldt F, Fleischer R. Experimentelle Beiträge zur Pathologie des Stoffwechsels mit besonderer Berücksichtigung des Einflusses von Respirationsstörungen. Virchows Arch 1882. [DOI: 10.1007/bf01880511] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Leube W, Fleischer R. Ein Beitrag zur Lehre von der Leukämie. Virchows Arch 1881. [DOI: 10.1007/bf01932571] [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: 10/25/2022]
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