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Krieger IV, Yalamanchili S, Dickson P, Engelhart CA, Zimmerman MD, Wood J, Clary E, Nguyen J, Thornton N, Centrella PA, Chan B, Cuozzo JW, Gengenbacher M, Guié MA, Guilinger JP, Bienstock C, Hartl H, Hupp CD, Jetson R, Satoh T, Yeoman JTS, Zhang Y, Dartois V, Schnappinger D, Keefe AD, Sacchettini JC. Inhibitors of the Thioesterase Activity of Mycobacterium tuberculosis Pks13 Discovered Using DNA-Encoded Chemical Library Screening. ACS Infect Dis 2024; 10:1561-1575. [PMID: 38577994 DOI: 10.1021/acsinfecdis.3c00592] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
DNA-encoded chemical library (DEL) technology provides a time- and cost-efficient method to simultaneously screen billions of compounds for their affinity to a protein target of interest. Here we report its use to identify a novel chemical series of inhibitors of the thioesterase activity of polyketide synthase 13 (Pks13) from Mycobacterium tuberculosis (Mtb). We present three chemically distinct series of inhibitors along with their enzymatic and Mtb whole cell potency, the measure of on-target activity in cells, and the crystal structures of inhibitor-enzyme complexes illuminating their interactions with the active site of the enzyme. One of these inhibitors showed a favorable pharmacokinetic profile and demonstrated efficacy in an acute mouse model of tuberculosis (TB) infection. These findings and assay developments will aid in the advancement of TB drug discovery.
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Affiliation(s)
- Inna V Krieger
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas 77843, United States
| | | | - Paige Dickson
- X-Chem Inc., 100 Beaver Street, Waltham, Massachusetts 02453, United States
| | - Curtis A Engelhart
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, New York 10021, United States
| | - Matthew D Zimmerman
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey 07110, United States
| | - Jeremy Wood
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas 77843, United States
| | - Ethan Clary
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas 77843, United States
| | - Jasmine Nguyen
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas 77843, United States
| | - Natalie Thornton
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, New York 10021, United States
| | - Paolo A Centrella
- X-Chem Inc., 100 Beaver Street, Waltham, Massachusetts 02453, United States
| | - Betty Chan
- X-Chem Inc., 100 Beaver Street, Waltham, Massachusetts 02453, United States
- Auron Therapeutics, 55 Chapel Street, Newton, Massachusetts 02458, United States
| | - John W Cuozzo
- X-Chem Inc., 100 Beaver Street, Waltham, Massachusetts 02453, United States
- Relay Therapeutics, 399 Binney Street, Cambridge, Massachusetts 02141, United States
| | - Martin Gengenbacher
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey 07110, United States
| | - Marie-Aude Guié
- X-Chem Inc., 100 Beaver Street, Waltham, Massachusetts 02453, United States
| | - John P Guilinger
- X-Chem Inc., 100 Beaver Street, Waltham, Massachusetts 02453, United States
| | - Corey Bienstock
- X-Chem Inc., 100 Beaver Street, Waltham, Massachusetts 02453, United States
| | - Hajnalka Hartl
- X-Chem Inc., 100 Beaver Street, Waltham, Massachusetts 02453, United States
- Orogen Therapeutics, 12 Gill Street, Woburn, Massachusetts 01801, United States
| | - Christopher D Hupp
- X-Chem Inc., 100 Beaver Street, Waltham, Massachusetts 02453, United States
- Ipsen Bioscience Inc., 1 Main Street, Cambridge, Massachusetts 02142, United States
| | - Rachael Jetson
- X-Chem Inc., 100 Beaver Street, Waltham, Massachusetts 02453, United States
- Valo Health, 75 Hayden Avenue, Lexington, Massachusetts 02141, United States
| | - Takashi Satoh
- X-Chem Inc., 100 Beaver Street, Waltham, Massachusetts 02453, United States
- EXO Therapeutics, 150 Cambridgepark Drive, suite 300, Cambridge, Massachusetts 02140, United States
| | - John T S Yeoman
- X-Chem Inc., 100 Beaver Street, Waltham, Massachusetts 02453, United States
- Recludix Pharmaceuticals, 222 Third Street, Cambridge, Massachusetts 02142, United States
| | - Ying Zhang
- X-Chem Inc., 100 Beaver Street, Waltham, Massachusetts 02453, United States
| | - Veronique Dartois
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey 07110, United States
- Hackensack Meridian School of Medicine, Hackensack Meridian Health, Nutley, New Jersey 07110, United States
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, New York 10021, United States
| | - Anthony D Keefe
- X-Chem Inc., 100 Beaver Street, Waltham, Massachusetts 02453, United States
| | - James C Sacchettini
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas 77843, United States
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Dickson P. DNA-Encoded Library Technology─A Catalyst for Covalent Ligand Discovery. ACS Chem Biol 2024; 19:802-808. [PMID: 38527941 DOI: 10.1021/acschembio.3c00803] [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] [Indexed: 03/27/2024]
Abstract
The identification of novel covalent ligands for therapeutic purposes has long depended on serendipity, with dedicated hit finding techniques emerging only in the early 2000s. Advances in chemoproteomics have enabled robust characterization of putative drugs to derisk the unique liabilities associated with covalent hit molecules, leading to a renewed interest in this targeting modality. DNA-encoded library (DEL) technology has similarly emerged over the past two decades as a highly efficient method to identify new chemical equity toward protein targets of interest. A number of commercial and academic groups have reported methods in covalent DEL synthesis and hit identification; however, it is evident that there is still much to be done to fully realize the power of this technology for covalent ligand discovery. This perspective will explore the current approaches in covalent DEL technology and reflect on the next steps to advance this field.
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Affiliation(s)
- Paige Dickson
- X-Chem Inc., 100 Beaver Street, Waltham, Massachusetts 02453, United States
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Dickson P, Abegg D, Vinogradova E, Takaya J, An H, Simanski S, Cravatt BF, Adibekian A, Kodadek T. Physical and Functional Analysis of the Putative Rpn13 Inhibitor RA190. Cell Chem Biol 2020; 27:1371-1382.e6. [PMID: 32857985 DOI: 10.1016/j.chembiol.2020.08.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [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: 11/04/2019] [Revised: 05/22/2020] [Accepted: 08/07/2020] [Indexed: 12/12/2022]
Abstract
Rpn13 is one of several ubiquitin receptors in the 26S proteasome. Cys88 of Rpn13 has been proposed to be the principal target of RA190, an electrophilic small molecule with interesting anti-cancer activities. Here, we examine the claim that RA190 mediates its cytotoxic effects through engagement with Rpn13. We find no evidence that this is the case. In vitro, RA190 is has no measurable effect on any of the known interactions of Rpn13. In cellulo, we see no physical engagement of Rpn13 by RA190, either on C88 or any other residue. However, chemical proteomics experiments in two different cell lines reveal that dozens of other proteins are heavily engaged by RA190. Finally, increasing or reducing the level of Rpn13 in HeLa and melanoma cells had no effect on the sensitivity of HeLa or melanoma cells to RA190. We conclude that Rpn13 is not the physiologically relevant target of RA190.
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Affiliation(s)
- Paige Dickson
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Daniel Abegg
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Ekaterina Vinogradova
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Junichiro Takaya
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Hongchan An
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Scott Simanski
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Benjamin F Cravatt
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Alexander Adibekian
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Thomas Kodadek
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA.
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Dickson P, Simanski S, Ngundu JM, Kodadek T. Mechanistic Studies of the Multiple Myeloma and Melanoma Cell-Selective Toxicity of the Rpn13-Binding Peptoid KDT-11. Cell Chem Biol 2020; 27:1383-1395.e5. [PMID: 32857986 DOI: 10.1016/j.chembiol.2020.08.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [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: 11/05/2019] [Revised: 05/22/2020] [Accepted: 08/07/2020] [Indexed: 12/12/2022]
Abstract
We previously reported a peptoid ligand for the proteasomal ubiquitin receptor Rpn13 called KDT-11 and demonstrated that this compound is toxic to multiple myeloma cells, but not non-malignant cells. Here, we show that KDT-11 decreases the viability of a variety of cancer cell lines, especially melanomas and various blood cancers. The peptoid induces selective G1 cell-cycle arrest, resulting in eventual apoptosis. While KDT-11 does not antagonize any of the known protein-protein interactions involving Rpn13, the peptoid inhibits the ability of Rpn13 to stimulate the activity of an associated deubiquitylase Uch37/UCHL5 in vitro, suggesting a high level of Uch37 activity might be important for cancer cell proliferation. However, a variety of experiments in SK-MEL-5 melanoma cells suggest that KDT-11's cytotoxic effects are mediated by interactions with proteins other than Rpn13.
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Affiliation(s)
- Paige Dickson
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Scott Simanski
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - John Maina Ngundu
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Thomas Kodadek
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA.
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Abstract
Long noncoding RNAs (lncRNAs) have emerged as essential cellular regulators and potential disease targets. In this issue of Cell Chemical Biology, Shi et al. (2019) identify a cyclic peptide that results in restored glucose processing in type 2 diabetes mellitus (T2DM) patient derived adipocytes through stabilization of lncRNA GAS5.
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Affiliation(s)
- Paige Dickson
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Thomas Kodadek
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA.
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Abstract
DNA-encoded library (DEL) screening has emerged as an important method for early stage drug and probe molecule discovery. The vast majority of screens using DELs have been relatively simple binding assays. The library is incubated with a target molecule, which is almost always a protein, and the DNAs that remain associated with the target after thorough washing are amplified and deep sequenced to reveal the chemical structures of the ligands they encode. Recently however, a number of different screening formats have been introduced that demand more than simple binding. These include a format that demands hits exhibit high selectivity for target vs. off-targets, a protocol to screen for enzyme inhibitors and another to identify organocatalysts in a DEL. These and other novel assay formats are reviewed in this article. We also consider some of the most significant remaining challenges in DEL assay development.
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Affiliation(s)
- Thomas Kodadek
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA.
| | - Nicholas G Paciaroni
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA.
| | - Madeline Balzarini
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA.
| | - Paige Dickson
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA.
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Abstract
DNA-encoded libraries represent an exciting and powerful modality for high-throughput screening. In this article, we highlight recent important advances in this field and also suggest some important directions that would make the technology even more powerful.
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Affiliation(s)
- Paige Dickson
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA.
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Tran Mau-Them F, Guibaud L, Duplomb L, Keren B, Lindstrom K, Marey I, Mochel F, van den Boogaard MJ, Oegema R, Nava C, Masurel A, Jouan T, Jansen FE, Au M, Chen AH, Cho M, Duffourd Y, Lozier E, Konovalov F, Sharkov A, Korostelev S, Urteaga B, Dickson P, Vera M, Martínez-Agosto JA, Begemann A, Zweier M, Schmitt-Mechelke T, Rauch A, Philippe C, van Gassen K, Nelson S, Graham JM, Friedman J, Faivre L, Lin HJ, Thauvin-Robinet C, Vitobello A. De novo truncating variants in the intronless IRF2BPL are responsible for developmental epileptic encephalopathy. Genet Med 2018; 21:1008-1014. [DOI: 10.1038/s41436-018-0143-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 07/13/2018] [Indexed: 02/06/2023] Open
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McCartney J, Dickson P, Kodadek T. Towards the Identification of the Minimal Pharmacophore of KDT‐11. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.531.3] [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: 11/11/2022]
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Pels K, Dickson P, An H, Kodadek T. DNA-Compatible Solid-Phase Combinatorial Synthesis of β-Cyanoacrylamides and Related Electrophiles. ACS Comb Sci 2018; 20:61-69. [PMID: 29298042 DOI: 10.1021/acscombsci.7b00169] [Citation(s) in RCA: 15] [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] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We demonstrate that the Knoevenagel condensation can be exploited in combinatorial synthesis on the solid phase. Condensation products from such reactions were structurally characterized, and their Michael reactivity with thiol and phosphine nucleophiles is described. Cyanoacrylamides were previously reported to react reversibly with thiols, and notably, we show that dilution into low pH buffer can trap covalent adducts, which are isolable via chromatography. Finally, we synthesized both traditional and DNA-encoded one-bead, one-compound libraries containing cyanoacrylamides as a source of cysteine-reactive reversibly covalent protein ligands.
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Affiliation(s)
- Kevin Pels
- Department of Chemistry, The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Paige Dickson
- Department of Chemistry, The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Hongchan An
- Department of Chemistry, The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Thomas Kodadek
- Department of Chemistry, The Scripps Research Institute, Jupiter, Florida 33458, United States
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Trader DJ, Simanski S, Dickson P, Kodadek T. Establishment of a suite of assays that support the discovery of proteasome stimulators. Biochim Biophys Acta Gen Subj 2017; 1861:892-899. [PMID: 28065760 DOI: 10.1016/j.bbagen.2017.01.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [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: 07/28/2016] [Revised: 12/03/2016] [Accepted: 01/03/2017] [Indexed: 12/30/2022]
Abstract
BACKGROUND The proteasome catalyzes the degradation of many mis-folded proteins, which are otherwise cytotoxic. There is interest in the discovery of proteasome agonists, but previous efforts to do so have been disappointing. METHODS The cleavage of small fluorogenic peptides is used routinely as an assay to screen for proteasome modulators. We have developed follow-on assays that employ more physiologically relevant substrates. RESULTS To demonstrate the efficacy of this workflow, the NIH Clinical Collection (NCC) was screened. While many compounds stimulated proteasome-mediated proteolysis of the pro-fluorogenic peptide substrates, most failed to evince activity in assays with larger peptide or protein substrates. We also show that two molecules claimed previously to be proteasome agonists, oleuropein and betulinic acid, indeed accelerate hydrolysis of the fluorogenic substrate, but have no effect on the turnover of a mis-folded protein in vitro or in cellulo. However, two small molecules from the NCC, MK-866 and AM-404, stimulate the proteasome-mediated turnover of a mis-folded protein in living cells by 3- to 4-fold. CONCLUSION Assays that monitor the proteasome-mediated degradation of larger peptides and proteins can distinguish bona fide agonists from compounds only able to stimulate the cleavage of short, non-physiologically relevant peptides. GENERAL SIGNIFICANCE A suite of assays has been established that allows the discovery of bona fide proteasome agonists. AM-404 and MK-866 can be useful tools for cell culture experiments, and can serve as scaffolds to generate more potent 20S stimulators.
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Affiliation(s)
- Darci J Trader
- Departments of Chemistry and Cancer Biology, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, United States
| | - Scott Simanski
- Departments of Chemistry and Cancer Biology, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, United States
| | - Paige Dickson
- Departments of Chemistry and Cancer Biology, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, United States
| | - Thomas Kodadek
- Departments of Chemistry and Cancer Biology, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, United States.
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Calton M, Dickson P, Harper RM, Goldowitz D, Mittleman G. Impaired hypercarbic and hypoxic responses from developmental loss of cerebellar Purkinje neurons: implications for sudden infant death syndrome. Cerebellum 2015; 13:739-50. [PMID: 25132500 DOI: 10.1007/s12311-014-0592-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Impaired responsivity to hypercapnia or hypoxia is commonly considered a mechanism of failure in sudden infant death syndrome (SIDS). The search for deficient brain structures mediating flawed chemosensitivity typically focuses on medullary regions; however, a network that includes Purkinje cells of the cerebellar cortex and its associated cerebellar nuclei also helps mediate responses to carbon dioxide (CO2) and oxygen (O2) challenges and assists integration of cardiovascular and respiratory interactions. Although cerebellar nuclei contributions to chemoreceptor challenges in adult models are well described, Purkinje cell roles in developing models are unclear. We used a model of developmental cerebellar Purkinje cell loss to determine if such loss influenced compensatory ventilatory responses to hypercapnic and hypoxic challenges. Twenty-four Lurcher mutant mice and wild-type controls were sequentially exposed to 2% increases in CO2 (0-8%) or 2% reductions in O2 (21-13%) over 4 min, with return to room air (21% O2/79% N2/0% CO2) between each exposure. Whole body plethysmography was used to continuously monitor tidal volume (TV) and breath frequency (f). Increased f to hypercapnia was significantly lower in mutants, slower to initiate, and markedly lower in compensatory periods, except for very high (8%) CO2 levels. The magnitude of TV changes to increasing CO2 appeared smaller in mutants but only approached significance. Smaller but significant differences emerged in response to hypoxia, with mutants showing smaller TV when initially exposed to reduced O2 and lower f following exposure to 17% O2. Since cerebellar neuropathology appears in SIDS victims, developmental cerebellar neuropathology may contribute to SIDS vulnerability.
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Affiliation(s)
- M Calton
- Department of Psychology, The University of Memphis, 400 Innovation Drive, Memphis, TN, 38152, USA
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Dickson P, Bell D, Scholfield N, Johnson C. P5.4 Contribution of NPY Y1 and NPY Y2 receptors to sympathetic vasoconstriction in the diabetic streptozotocin-treated rat tail artery at two time points. Auton Neurosci 2009. [DOI: 10.1016/j.autneu.2009.05.194] [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: 11/28/2022]
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Tolar J, Dickson P, Orchard P. Intravenous and Intrathecal Enzyme Replacement Before and After Hematopoietic Cell Transplantation for Hurler Syndrome. Biol Blood Marrow Transplant 2009. [DOI: 10.1016/j.bbmt.2008.12.230] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Tiranti V, Briem E, Lamantea E, Mineri R, Papaleo E, De Gioia L, Forlani F, Rinaldo P, Dickson P, Abu-Libdeh B, Cindro-Heberle L, Owaidha M, Jack RM, Christensen E, Burlina A, Zeviani M. ETHE1 mutations are specific to ethylmalonic encephalopathy. J Med Genet 2005; 43:340-6. [PMID: 16183799 PMCID: PMC2563233 DOI: 10.1136/jmg.2005.036210] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [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: 11/04/2022]
Abstract
Mutations in ETHE1, a gene located at chromosome 19q13, have recently been identified in patients affected by ethylmalonic encephalopathy (EE). EE is a devastating infantile metabolic disorder, characterised by widespread lesions in the brain, hyperlactic acidaemia, petechiae, orthostatic acrocyanosis, and high levels of ethylmalonic acid in body fluids. To investigate to what extent ETHE1 is responsible for EE, we analysed this gene in 29 patients with typical EE and in 11 patients presenting with early onset progressive encephalopathy with ethylmalonic aciduria (non-EE EMA). Frameshift, stop, splice site, and missense mutations of ETHE1 were detected in all the typical EE patients analysed. Western blot analysis of the ETHE1 protein indicated that some of the missense mutations are associated with the presence of the protein, suggesting that the corresponding wild type amino acid residues have a catalytic function. No ETHE1 mutations were identified in non-EE EMA patients. Experiments based on two dimensional blue native electrophoresis indicated that ETHE1 protein works as a supramolecular, presumably homodimeric, complex, and a three dimensional model of the protein suggests that it is likely to be a mitochondrial matrix thioesterase acting on a still unknown substrate. Finally, the 625G-->A single nucleotide polymorphism in the gene encoding the short chain acyl-coenzyme A dehydrogenase (SCAD) was previously proposed as a co-factor in the aetiology of EE and other EMA syndromes. SNP analysis in our patients ruled out a pathogenic role of SCAD variants in EE, but did show a highly significant prevalence of the 625A alleles in non-EE EMA patients.
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Affiliation(s)
- V Tiranti
- Unit of Molecular Neurogenetics, Pierfranco and Luisa Mariani Center for the Study ofChildren's Mitochondrial Disorders, National Neurological Institute C. Besta, Via Temolo 4, 20126 Milan, Italy
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Kakkis E, McEntee M, Vogler C, Le S, Levy B, Belichenko P, Mobley W, Dickson P, Hanson S, Passage M. Intrathecal enzyme replacement therapy reduces lysosomal storage in the brain and meninges of the canine model of MPS I. Mol Genet Metab 2004; 83:163-74. [PMID: 15464431 DOI: 10.1016/j.ymgme.2004.07.003] [Citation(s) in RCA: 135] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2004] [Revised: 07/05/2004] [Accepted: 07/07/2004] [Indexed: 11/19/2022]
Abstract
Enzyme replacement therapy (ERT) has been developed for several lysosomal storage disorders, including mucopolysaccharidosis I (MPS I), and is effective at reducing lysosomal storage in many tissues and in ameliorating clinical disease. However, intravenous ERT does not adequately treat storage disease in the central nervous system (CNS), presumably due to effects of the blood-brain barrier on enzyme distribution. To circumvent this barrier, we studied whether intrathecal (IT) recombinant human alpha-L-iduronidase (rhIDU) could penetrate and treat the brain and meninges. An initial dose-response study showed that doses of 0.46-4.14 mg of IT rhIDU successfully penetrated the brain of normal dogs and reached tissue levels 5.6 to 18.9-fold normal overall and 2.7 to 5.9-fold normal in deep brain sections lacking CSF contact. To assess the efficacy and safety in treating lysosomal storage disease, four weekly doses of approximately 1 mg of IT rhIDU were administered to MPS I-affected dogs resulting in a mean 23- and 300-fold normal levels of iduronidase in total brain and meninges, respectively. Quantitative glycosaminoglycan (GAG) analysis showed that the IT treatment reduced mean total brain GAG to normal levels and achieved a 57% reduction in meningeal GAG levels accompanied by histologic improvement in lysosomal storage in all cell types. The dogs did develop a dose-dependent immune response against the recombinant human protein and a meningeal lymphocytic/plasmacytic infiltrate. The IT route of ERT administration may be an effective way to treat the CNS disease in MPS I and could be applicable to other lysosomal storage disorders.
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Affiliation(s)
- E Kakkis
- Division of Medical Genetics, Department of Pediatrics, Harbor-UCLA Research and Education Institute, Torrance CA, USA.
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Dickson P, Greasley P, Small N. The Bradford salaried non-principal scheme: addressing the problems of GP recruitment and retention in the inner city – it's not just the money but the support. Prim Health Care Res Dev 2002. [DOI: 10.1191/1463423602pc096oa] [Citation(s) in RCA: 1] [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: 11/05/2022] Open
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Dickson P. Passage of the lines. Army Q Def J 2001; 112:199-204. [PMID: 11614229] [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: 02/21/2023]
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Tsaroucha A, Webb M, Karatzas T, Dickson P, Demirbas A, Fragulidis G, Nery J, Khan F, Tzakis A. Management of allograft-replaced right hepatic arteries in liver transplantation: a review of the University of Miami experience and a preferred method of reconstruction. Transplant Proc 1997; 29:2856-8. [PMID: 9365591 DOI: 10.1016/s0041-1345(97)00707-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- A Tsaroucha
- University of Miami School of Medicine, Department of Surgery, FL, USA
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Kamitani A, Wong ZY, Dickson P, van Herwerden L, Raven J, Forbes AB, Abramson MJ, Walters EH, Harrap SB. Absence of genetic linkage of chromosome 5q31 with asthma and atopy in the general population. Thorax 1997; 52:816-7. [PMID: 9371215 PMCID: PMC1758647 DOI: 10.1136/thx.52.9.816] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [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: 02/05/2023]
Abstract
BACKGROUND Clinical asthma is associated with increased serum total immunoglobulin E (IgE), atopy (skin prick test positivity to common aeroallergens), and bronchial hyperreactivity (BHR) to non-specific stimuli (positive methacholine challenge test). A region on chromosome 5q31-33 has been linked with increased total serum IgE and BHR. A study of the genetic linkage of this region with clinical asthma and atopy was therefore undertaken. METHODS A polymorphic microsatellite marker in chromosome 5q31 (D5S399) was studied in 119 sibling pairs recruited from the general population who shared asthma, atopy, and/or BHR. Based on our population distribution of 13 different alleles, it was expected that by chance alone sibling pairs would share on average 1.24 alleles and that a significant excess would indicate genetic linkage. RESULTS No evidence of linkage was found in 45 siblings concordant for asthma (shared alleles = 1.09, p = 0.95), in 103 sibling pairs with atopy (shared alleles = 1.18, p = 0.82), in 51 sibling pairs with BHR (shared alleles = 1.22, p = 0.62), or in 68 sibling pairs who shared atopy in the absence of BHR (shared alleles = 1.22, p = 0.61). A slight non-significant excess of shared alleles (1.44, p = 0.11) was observed in siblings who shared BHR without atopy. CONCLUSIONS No evidence of genetic linkage of chromosome 5q31 with either clinical asthma or atopy was therefore detected in the population studied. Linkage between chromosome 5q and BHR needs further investigation.
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Affiliation(s)
- A Kamitani
- Department of Physiology, University of Melbourne, Parkville, Victoria, Australia
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Abstract
Duodenal administration of casein and oleate increased plasma levels from oral administration of a poorly water-soluble antiepileptic drug as compared to duodenal glucose and saline in a canine model. Pre-treatment with intravenous MK-329, benzodiazepine CCK A-receptor antagonist, blocked the duodenal oleate effect on drug plasma levels in a single dog preliminary study. In a follow-up study, oral drug co-administration with Intralipid increased drug plasma levels as compared to drug co-administration with a noncaloric equivalent-volume load in seven dogs. Pre-treatment with MK-329 reduced drug plasma levels from co-administration with Intralipid toward fasted-state values. While increased drug solubility in the lipid vehicle might have been projected to account for the fed-state effect in the oral studies, the gut peptide inhibitor studies suggest that biliary secretion plays a major role in promoting the dissolution and subsequent absorption of this lipophilic drug. The data also support the hypothesis that meal-enhanced pancreatic secretion provides a greater fluid volume for drug dissolution in the small intestine. An increase in the extent of drug dissolution in the stomach, as a result of meal prolongation of gastric residence time, does not appear to contribute substantially to fed-state increases in drug plasma levels from oral drug co-administration with a lipid meal.
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Affiliation(s)
- C Miles
- College of Pharmacy, University of Michigan, Ann Arbor 48109-1065, USA
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Abstract
Constant light exposure (LL) can result in "splitting" of circadian rhythms into two components coupled about 12 hr apart. Splitting has been interpreted as evidence for the presence of two main oscillators or groups of oscillators underlying circadian rhythms. Abolition of splitting after unilateral suprachiasmatic nucleus ablation suggested that each suprachiasmatic nucleus could correspond to one of these component oscillators. We examined whether lesions outside the suprachiasmatic nuclei (SCN) would abolish split activity rhythms of hamsters in LL. Wheel-running activity was recorded for 3 months after surgery. Tissue damage was assessed by Klüver-Barrera staining. Damage to areas dorso-caudal to the SCN was able to abolish the split condition. Bilateral damage to the anterior SCN, partial unilateral SCN ablation or unilateral periventricular damage also abolished the split pattern. These results indicate that destruction of one SCN is not essential for the elimination of split rhythms since lesions dorsal to the SCN or partial bilateral SCN damage are also effective. Indirect lesion effects on SCN function or damage to extra-SCN oscillators may account for the loss of the split condition.
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Affiliation(s)
- M E Harrington
- Department of Psychology, Dalhousie University, Halifax, Canada
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Blouin RA, Dickson P, McNamara PJ, Cibull M, McClain C. Phenobarbital induction and acetaminophen hepatotoxicity: resistance in the obese Zucker rodent. J Pharmacol Exp Ther 1987; 243:565-70. [PMID: 3681696] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The obese Zucker rodent appears to lack a significant induction response after phenobarbital pretreatment. Induction of the hepatic cytochrome P-450 system with phenobarbital is known to enhance acetaminophen hepatotoxicity. The purpose of this study was to evaluate the influence of phenobarbital enzyme induction on acetaminophen hepatotoxicity in the obese and lean Zucker rodent. A preliminary study was performed evaluating the pharmacokinetics of acetaminophen in both the obese and lean Zucker rats. Data were utilized to calculate appropriate loading doses of acetaminophen during the subsequent hepatotoxicity study. Phenobarbital enzyme-inducing regimens were administered p.o. to achieve similar steady-state phenobarbital plasma concentrations. Control rats received appropriate placebo solutions. Serum hepatic transaminase enzymes and histologic evidence of hepatocellular necrosis were utilized to evaluate hepatic damage after p.o. administration of 1300 mg of acetaminophen to both obese and lean Zucker rats. Obese Zucker control animals had approximately 2.5 times the total hepatic glutathione content compared to their lean control (164.9 +/- 43.2 vs. 65.3 +/- 18.4 mumol/whole liver). Obese Zucker animals receiving only acetaminophen showed a trend toward a reduced incidence of hepatocellular necrosis compared to similarly treated lean littermates. Obese Zucker rodents pretreated with phenobarbital had an even more pronounced resistance to acetaminophen-induced hepatocellular necrosis (P less than .01) when compared to similarly treated lean littermates. Thus, acetaminophen hepatotoxicity is reduced in the obese Zucker rat and pretreatment with phenobarbital offers further protection against hepatocellular damage. We suggest that the previously unrecognized increase in hepatic glutathione plays a major role in the resistance of the obese Zucker rat to acetaminophen hepatotoxicity.
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Affiliation(s)
- R A Blouin
- College of Pharmacy, University of Kentucky, Lexington
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DiPiro JT, Michael KA, Clark BA, Dickson P, Vallner JJ, Bowden TA, Tedesco FJ. Absorption of polyethylene glycol after administration of a PEG-electrolyte lavage solution. Clin Pharm 1986; 5:153-5. [PMID: 3956124] [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: 01/08/2023]
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Dickson P. Su Clinica Familiar, Harlingen, Texas. Public Health Rep 1979; 94:56-63. [PMID: 472105 PMCID: PMC1426246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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