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Fatima I, Uppada JP, Chhonker YS, Gowrikumar S, Barman S, Roy S, Tolentino KT, Palermo N, Natarajan A, Beauchamp DR, Vecchio A, Murry DJ, Singh AB, Hopkins CR, Dhawan P. Identification and characterization of a first-generation inhibitor of claudin-1 in colon cancer progression and metastasis. Biomed Pharmacother 2023; 159:114255. [PMID: 36696800 PMCID: PMC10824272 DOI: 10.1016/j.biopha.2023.114255] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 01/07/2023] [Accepted: 01/14/2023] [Indexed: 01/25/2023] Open
Abstract
Colorectal cancer (CRC) is a leading cause of the cancer-related deaths worldwide. Thus, developing novel and targeted therapies for inhibiting CRC progression and metastasis is urgent. Several studies, including ours, have reported a causal role for an upregulated claudin-1 expression in promoting CRC metastasis through the activation of the Src and β-catenin-signaling. In murine models of colon tumorigenesis, claudin-1 overexpression promotes oncogenic properties such as transformation and invasiveness. Conversely, the downregulation of claudin-1 inhibits colon tumorigenesis. Despite being a desirable target for cancer treatment, there are currently no known claudin-1 inhibitors with antitumor efficacy. Using a rigorous analytical design and implementing in- vitro and in-vivo testing and a brief medicinal chemistry campaign, we identified a claudin-1-specific inhibitor and named it I-6. Despite its high potency, I-6 was rapidly cleared in human liver microsomes. We, therefore, synthesized I-6 analogs and discovered a novel small molecule, PDS-0330. We determined that PDS0330 inhibits claudin-1-dependent CRC progression without exhibiting toxicity in in-vitro and in-vivo models of CRC and that it binds directly and specifically to claudin-1 with micromolar affinity. Further analyses revealed that PDS-0330 exhibits antitumor and chemosensitizer activities with favorable pharmacokinetic properties by inhibiting the association with metastatic oncogene Src. Overall, our data propose that PDS-0330 interferes with claudin-1/Src association to inhibit CRC progression and metastasis. Our findings are of direct clinical relevance and may open new therapeutic opportunities in colon cancer treatment and/or management by targeting claudin-1.
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Affiliation(s)
- Iram Fatima
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Jaya Prakash Uppada
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Yashpal S Chhonker
- Department of Pharmacy Practice and Science, University of Nebraska Medical Center, Omaha, NE, USA
| | - Saiprasad Gowrikumar
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Susmita Barman
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Sourav Roy
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0664, USA
| | - Kirsten T Tolentino
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Nicholas Palermo
- Computational Chemistry Core, University of Nebraska Medical Center, Omaha, NE, USA
| | - Amar Natarajan
- Eppley Institute for Cancer Research, University of Nebraska Medical Center, Omaha, NE, USA
| | - Daniel R Beauchamp
- Surgical Oncology Research Laboratories, Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alex Vecchio
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0664, USA
| | - Daryl J Murry
- Department of Pharmacy Practice and Science, University of Nebraska Medical Center, Omaha, NE, USA; VA Nebraska-Western Iowa Health Care System, Omaha, NE, USA
| | - Amar B Singh
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA; VA Nebraska-Western Iowa Health Care System, Omaha, NE, USA; Buffet Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Corey R Hopkins
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Punita Dhawan
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA; VA Nebraska-Western Iowa Health Care System, Omaha, NE, USA; Buffet Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA.
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Wang LL, Palermo N, Estrada L, Thompson C, Patten JJ, Anantpadma M, Davey RA, Xiang SH. Identification of filovirus entry inhibitors targeting the endosomal receptor NPC1 binding site. Antiviral Res 2021; 189:105059. [PMID: 33705865 DOI: 10.1016/j.antiviral.2021.105059] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/27/2021] [Accepted: 03/04/2021] [Indexed: 12/20/2022]
Abstract
Filoviruses, mainly consisting of Ebola viruses (EBOV) and Marburg viruses (MARV), are enveloped negative-strand RNA viruses which can infect humans to cause severe hemorrhagic fevers and outbreaks with high mortality rates. The filovirus infection is mediated by the interaction of viral envelope glycoprotein (GP) and the human endosomal receptor Niemann-Pick C1 (NPC1). Blocking this interaction will prevent the infection. Therefore, we utilized an In silico screening approach to conduct virtual compound screening against the NPC1 receptor-binding site (RBS). Twenty-six top-hit compounds were purchased and evaluated by in vitro cell based inhibition assays against pseudotyped or replication-competent filoviruses. Two classes (A and U) of compounds were identified to have potent inhibitory activity against both Ebola and Marburg viruses. The IC50 values are in the lower level of micromolar concentrations. One compound (compd-A) was found to have a sub-micromolar IC50 value (0.86 μM) against pseudotyped Marburg virus. The cytotoxicity assay (MTT) indicates that compd-A has a moderate cytotoxicity level but the compd-U has much less toxicity and the CC50 value was about 100 μM. Structure-activity relationship (SAR) study has found some analogs of compd-A and -U have reduced the toxicity and enhanced the inhibitory activity. In conclusion, this work has identified several qualified lead-compounds for further drug development against filovirus infection.
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Affiliation(s)
- Leah Liu Wang
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA; Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Nicholas Palermo
- Computational Chemistry Core Facility, VCR Cores, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Leslie Estrada
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Colton Thompson
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - J J Patten
- National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA, 0211, USA
| | - Manu Anantpadma
- National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA, 0211, USA
| | - Robert A Davey
- National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA, 0211, USA
| | - Shi-Hua Xiang
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA; Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA.
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3
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Alshammari AM, Smith DD, Parriott J, Stewart JP, Curran SM, McCulloh RJ, Barry PA, Iyer SS, Palermo N, Phillips JA, Dong Y, Ronning DR, Vennerstrom JL, Sanderson SD, Vetro JA. Targeted Amino Acid Substitution Overcomes Scale-Up Challenges with the Human C5a-Derived Decapeptide Immunostimulant EP67. ACS Infect Dis 2020; 6:1169-1181. [PMID: 32233506 PMCID: PMC7279522 DOI: 10.1021/acsinfecdis.0c00005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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] [Indexed: 01/07/2023]
Abstract
EP67 is a second-generation, human C5a-derived decapeptide agonist of C5a receptor 1 (C5aR1/CD88) that selectively activates mononuclear phagocytes over neutrophils to potentiate protective innate and adaptive immune responses while potentially minimizing neutrophil-mediated toxicity. Pro7 and N-methyl-Leu8 (Me-Leu8) amino acid residues within EP67 likely induce backbone structural changes that increase potency and selective activation of mononuclear phagocytes over neutrophils versus first-generation EP54. The low coupling efficiency between Pro7 and Me-Leu8 and challenging purification by HPLC, however, greatly increase scale-up costs of EP67 for clinical use. Thus, the goal of this study was to determine whether replacing Pro7 and/or Me-Leu8 with large-scale amenable amino acid residues predicted to induce similar structural changes (cyclohexylalanine7 and/or leucine8) sufficiently preserves EP67 activity in primary human mononuclear phagocytes and neutrophils. We found that EP67 analogues had similar potency, efficacy, and selective activation of mononuclear phagocytes over neutrophils. Thus, replacing Pro7 and/or Me-Leu8 with large-scale amenable amino acid residues predicted to induce similar structural changes is a suitable strategy to overcome scale-up challenges with EP67.
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Affiliation(s)
- Abdulraman M. Alshammari
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - D. David Smith
- Department of Biomedical Sciences, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA
| | - Jake Parriott
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - Jason P. Stewart
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - Stephen M. Curran
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - Russell J. McCulloh
- Department of Pediatrics, Children’s Hospital and Medical Center, Omaha, Nebraska, 68114, USA
| | - Peter A. Barry
- Center for Immunology and Infectious Diseases, Pathology and Laboratory Medicine, UC Davis School of Medicine, Davis, CA 95817, USA
| | - Smita S. Iyer
- Center for Immunology and Infectious Diseases, Pathology, Microbiology & Immunology, UC Davis, School of Veterinary Medicine, California National Primate Research Center, Davis, CA 95817, USA
| | - Nicholas Palermo
- Holland Computing Center, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Joy A. Phillips
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, CA 92115, USA
| | - Yuxiang Dong
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - Donald R. Ronning
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - Jonathan L. Vennerstrom
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - Sam D. Sanderson
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - Joseph A. Vetro
- Center for Drug Delivery and Nanomedicine, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
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Abstract
Fruit flies must compensate for the limited light gathered by the tiny facets of their eyes, and image motion during flight lowers light catch even further. Motion blur is especially problematic in fast regions of the visual field, perpendicular to forward motion, but flow fields also contain slower regions, less affected by blur. To test whether fruit flies shift their attention to predictably slower regions of a flow field, we placed flies in an arena simulating forward flight and measured responses to turning cues in different visual areas. We find that during fast forward flight, fruit flies respond more strongly to turning cues presented directly in front, and less strongly to cues presented to the sides, supporting the hypothesis that flying fruit flies shift visual attention to slower moving regions less affected by motion blur.
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Affiliation(s)
- Nicholas Palermo
- Department of Biological Sciences, Florida International University , Miami, FL 33199 , USA
| | - Jamie Theobald
- Department of Biological Sciences, Florida International University , Miami, FL 33199 , USA
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Stroud JT, Colom M, Ferrer P, Palermo N, Vargas V, Cavallini M, Lopez J, Jones I. Behavioral shifts with urbanization may facilitate biological invasion of a widespread lizard. Urban Ecosyst 2019. [DOI: 10.1007/s11252-019-0831-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Pattnaik A, Palermo N, Sahoo BR, Yuan Z, Hu D, Annamalai AS, Vu HLX, Correas I, Prathipati PK, Destache CJ, Li Q, Osorio FA, Pattnaik AK, Xiang SH. Discovery of a non-nucleoside RNA polymerase inhibitor for blocking Zika virus replication through in silico screening. Antiviral Res 2017; 151:78-86. [PMID: 29274845 DOI: 10.1016/j.antiviral.2017.12.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 12/12/2017] [Accepted: 12/20/2017] [Indexed: 02/08/2023]
Abstract
Zika virus (ZIKV), an emerging arbovirus, has become a major human health concern globally due to its association with congenital abnormalities and neurological diseases. Licensed vaccines or antivirals against ZIKV are currently unavailable. Here, by employing a structure-based approach targeting the ZIKV RNA-dependent RNA polymerase (RdRp), we conducted in silico screening of a library of 100,000 small molecules and tested the top ten lead compounds for their ability to inhibit the virus replication in cell-based in vitro assays. One compound, 3-chloro-N-[({4-[4-(2-thienylcarbonyl)-1-piperazinyl]phenyl}amino)carbonothioyl]-1-benzothiophene-2-carboxamide (TPB), potently inhibited ZIKV replication at sub-micromolar concentrations. Molecular docking analysis suggests that TPB binds to the catalytic active site of the RdRp and therefore likely blocks the viral RNA synthesis by an allosteric effect. The IC50 and the CC50 of TPB in Vero cells were 94 nM and 19.4 μM, respectively, yielding a high selective index of 206. In in vivo studies using immunocompetent mice, TPB reduced ZIKV viremia significantly, indicating TPB as a potential drug candidate for ZIKV infections.
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Affiliation(s)
- Aryamav Pattnaik
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, USA
| | | | - Bikash R Sahoo
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, USA
| | - Zhe Yuan
- School of Biological Sciences, University of Nebraska-Lincoln, USA
| | - Duoyi Hu
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, USA
| | - Arun S Annamalai
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, USA
| | - Hiep L X Vu
- Department of Animal Sciences, University of Nebraska-Lincoln, USA; Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Ignacio Correas
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, USA
| | | | - Christopher J Destache
- School of Pharmacy and Health Professions, Creighton University, Omaha, NE 68178, USA; Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Qingsheng Li
- School of Biological Sciences, University of Nebraska-Lincoln, USA; Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Fernando A Osorio
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, USA; Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Asit K Pattnaik
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, USA; Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583, USA.
| | - Shi-Hua Xiang
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, USA; Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583, USA.
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7
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Knappe D, Goldbach T, Hatfield M, Palermo N, Weinert S, Sträter N, Hoffmann R, Lovas S. Proline-rich Antimicrobial Peptides Optimized for Binding to Escherichia coli Chaperone DnaK. Protein Pept Lett 2016; 23:1061-1071. [DOI: 10.2174/0929866523666160719124712] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/11/2016] [Accepted: 07/11/2016] [Indexed: 11/22/2022]
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8
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Mohapatra B, Ahmad G, Nadeau S, Zutshi N, An W, Scheffe S, Dong L, Feng D, Goetz B, Arya P, Bailey TA, Palermo N, Borgstahl GEO, Natarajan A, Raja SM, Naramura M, Band V, Band H. Protein tyrosine kinase regulation by ubiquitination: critical roles of Cbl-family ubiquitin ligases. Biochim Biophys Acta 2012; 1833:122-39. [PMID: 23085373 DOI: 10.1016/j.bbamcr.2012.10.010] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 10/05/2012] [Accepted: 10/08/2012] [Indexed: 12/20/2022]
Abstract
Protein tyrosine kinases (PTKs) coordinate a broad spectrum of cellular responses to extracellular stimuli and cell-cell interactions during development, tissue homeostasis, and responses to environmental challenges. Thus, an understanding of the regulatory mechanisms that ensure physiological PTK function and potential aberrations of these regulatory processes during diseases such as cancer are of broad interest in biology and medicine. Aside from the expected role of phospho-tyrosine phosphatases, recent studies have revealed a critical role of covalent modification of activated PTKs with ubiquitin as a critical mechanism of their negative regulation. Members of the Cbl protein family (Cbl, Cbl-b and Cbl-c in mammals) have emerged as dominant "activated PTK-selective" ubiquitin ligases. Structural, biochemical and cell biological studies have established that Cbl protein-dependent ubiquitination targets activated PTKs for degradation either by facilitating their endocytic sorting into lysosomes or by promoting their proteasomal degradation. This mechanism also targets PTK signaling intermediates that become associated with Cbl proteins in a PTK activation-dependent manner. Cellular and animal studies have established that the relatively broadly expressed mammalian Cbl family members Cbl and Cbl-b play key physiological roles, including their critical functions to prevent the transition of normal immune responses into autoimmune disease and as tumor suppressors; the latter function has received validation from human studies linking mutations in Cbl to human leukemia. These newer insights together with embryonic lethality seen in mice with a combined deletion of Cbl and Cbl-b genes suggest an unappreciated role of the Cbl family proteins, and by implication the ubiquitin-dependent control of activated PTKs, in stem/progenitor cell maintenance. Future studies of existing and emerging animal models and their various cell lineages should help test the broader implications of the evolutionarily-conserved Cbl family protein-mediated, ubiquitin-dependent, negative regulation of activated PTKs in physiology and disease.
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Affiliation(s)
- Bhopal Mohapatra
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
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9
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Mohapatra B, Ahmad G, Nadeau S, Zutshi N, An W, Scheffe S, Dong L, Feng D, Goetz B, Arya P, Bailey TA, Palermo N, Borgstahl GEO, Natarajan A, Raja SM, Naramura M, Band V, Band H. Protein tyrosine kinase regulation by ubiquitination: critical roles of Cbl-family ubiquitin ligases. Biochim Biophys Acta 2012. [PMID: 23085373 DOI: 10.1016/j.bbamcr] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Protein tyrosine kinases (PTKs) coordinate a broad spectrum of cellular responses to extracellular stimuli and cell-cell interactions during development, tissue homeostasis, and responses to environmental challenges. Thus, an understanding of the regulatory mechanisms that ensure physiological PTK function and potential aberrations of these regulatory processes during diseases such as cancer are of broad interest in biology and medicine. Aside from the expected role of phospho-tyrosine phosphatases, recent studies have revealed a critical role of covalent modification of activated PTKs with ubiquitin as a critical mechanism of their negative regulation. Members of the Cbl protein family (Cbl, Cbl-b and Cbl-c in mammals) have emerged as dominant "activated PTK-selective" ubiquitin ligases. Structural, biochemical and cell biological studies have established that Cbl protein-dependent ubiquitination targets activated PTKs for degradation either by facilitating their endocytic sorting into lysosomes or by promoting their proteasomal degradation. This mechanism also targets PTK signaling intermediates that become associated with Cbl proteins in a PTK activation-dependent manner. Cellular and animal studies have established that the relatively broadly expressed mammalian Cbl family members Cbl and Cbl-b play key physiological roles, including their critical functions to prevent the transition of normal immune responses into autoimmune disease and as tumor suppressors; the latter function has received validation from human studies linking mutations in Cbl to human leukemia. These newer insights together with embryonic lethality seen in mice with a combined deletion of Cbl and Cbl-b genes suggest an unappreciated role of the Cbl family proteins, and by implication the ubiquitin-dependent control of activated PTKs, in stem/progenitor cell maintenance. Future studies of existing and emerging animal models and their various cell lineages should help test the broader implications of the evolutionarily-conserved Cbl family protein-mediated, ubiquitin-dependent, negative regulation of activated PTKs in physiology and disease.
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Affiliation(s)
- Bhopal Mohapatra
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
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10
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Abstract
Putative M1 (high-affinity pirenzepine) muscarinic receptors in rabbit hippocampal membranes, treated with 0.1 mM N-ethylmaleimide (NEM), were selectively labeled with [3H]pirenzepine. A single class of binding sites was labeled with a Kd of 3.4 nM, consistent with the pharmacologically-defined M1 subtype of muscarinic receptors. While full muscarinic agonists bound to high- and low-affinity states of [3H]pirenzepine-labeled M1 sites with a KL/KH ratio of approximately 100, the ratio for partial muscarinic agonists was approximately 10. The high-affinity binding of all agonists tested required divalent cations, and was interconverted to low-affinity binding in the presence of the non-hydrolyzable GTP analogue, guanylyl imidodiphosphate (GppNHp). Direct labeling of the high-affinity agonist state of M1 receptors was achieved with 5 nM [3H]oxotremorine-M by selectively uncoupling the high-affinity agonist state of M2 (low-affinity pirenzepine) receptors with NEM. The rate of dissociation of [3H]Pxotremorine-M from M1 receptors was accelerated 6-fold by GppNHp. These results provide further evidence which suggests that putative M1 muscarinic receptors activate second messenger systems by coupling to NEM-insensitive guanine nucleotide-binding proteins.
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Affiliation(s)
- D D Flynn
- Department of Pharmacology, University of Miami School of Medicine, FL 33101
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Burstein S, Ozman K, Burstein E, Palermo N, Smith E. Prostaglandins and cannabis--XI. Inhibition of delta 1-tetrahydrocannabinol-induced hypotension by aspirin. Biochem Pharmacol 1982; 31:591-2. [PMID: 6279113 DOI: 10.1016/0006-2952(82)90165-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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12
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Salisbury RE, Mckeel D, Pruitt BA, Mason AD, Palermo N, Wade CW. Morphologic observations of neosheath development of undifferentiated connective tissue development around artificial tendons. J Biomed Mater Res 1974; 8:175-84. [PMID: 4281783 DOI: 10.1002/jbm.820080318] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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13
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Luppi AC, Palermo N. [Factors which can impede the extraction of the crystalline lens with the Dr. Luppi model thermo-phako extractor L 65]. Arch Oftalmol B Aires 1966; 41:29-33. [PMID: 5986776] [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: 01/17/2023]
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