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Zhou A, Kong T, Fowles JS, Jung CL, Allen MJ, Fisher DAC, Fulbright M, Nemeth E, Ganz T, Oh ST. Hepcidin is elevated in primary and secondary myelofibrosis and remains elevated in patients treated with ruxolitinib. Br J Haematol 2022; 197:e49-e52. [PMID: 35128632 DOI: 10.1111/bjh.18044] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 12/22/2021] [Accepted: 01/03/2022] [Indexed: 02/15/2024]
Affiliation(s)
- Amy Zhou
- Washington University in St. Louis, St. Louis, Missouri, USA
| | - Tim Kong
- Washington University in St. Louis, St. Louis, Missouri, USA
| | - Jared S Fowles
- Washington University in St. Louis, St. Louis, Missouri, USA
| | | | - Maggie J Allen
- Washington University in St. Louis, St. Louis, Missouri, USA
| | | | - Mary Fulbright
- Washington University in St. Louis, St. Louis, Missouri, USA
| | | | - Tomas Ganz
- University of California, California, Los Angeles, USA
| | - Stephen T Oh
- Washington University in St. Louis, St. Louis, Missouri, USA
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2
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Matte A, Federti E, Kung C, Kosinski PA, Narayanaswamy R, Russo R, Federico G, Carlomagno F, Desbats MA, Salviati L, Leboeuf C, Valenti MT, Turrini F, Janin A, Yu S, Beneduce E, Ronseaux S, Iatcenko I, Dang L, Ganz T, Jung CL, Iolascon A, Brugnara C, De Franceschi L. The pyruvate kinase activator mitapivat reduces hemolysis and improves anemia in a β-thalassemia mouse model. J Clin Invest 2021; 131:144206. [PMID: 33822774 DOI: 10.1172/jci144206] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [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: 09/14/2020] [Accepted: 03/31/2021] [Indexed: 12/24/2022] Open
Abstract
Anemia in β-thalassemia is related to ineffective erythropoiesis and reduced red cell survival. Excess free heme and accumulation of unpaired α-globin chains impose substantial oxidative stress on β-thalassemic erythroblasts and erythrocytes, impacting cell metabolism. We hypothesized that increased pyruvate kinase activity induced by mitapivat (AG-348) in the Hbbth3/+ mouse model for β-thalassemia would reduce chronic hemolysis and ineffective erythropoiesis through stimulation of red cell glycolytic metabolism. Oral mitapivat administration ameliorated ineffective erythropoiesis and anemia in Hbbth3/+ mice. Increased ATP, reduced reactive oxygen species production, and reduced markers of mitochondrial dysfunction associated with improved mitochondrial clearance suggested enhanced metabolism following mitapivat administration in β-thalassemia. The amelioration of responsiveness to erythropoietin resulted in reduced soluble erythroferrone, increased liver Hamp expression, and diminished liver iron overload. Mitapivat reduced duodenal Dmt1 expression potentially by activating the pyruvate kinase M2-HIF2α axis, representing a mechanism additional to Hamp in controlling iron absorption and preventing β-thalassemia-related liver iron overload. In ex vivo studies on erythroid precursors from patients with β-thalassemia, mitapivat enhanced erythropoiesis, promoted erythroid maturation, and decreased apoptosis. Overall, pyruvate kinase activation as a treatment modality for β-thalassemia in preclinical model systems had multiple beneficial effects in the erythropoietic compartment and beyond, providing a strong scientific basis for further clinical trials.
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Affiliation(s)
- Alessandro Matte
- Department of Medicine, University of Verona, and Azienda Ospedaliera Universitaria Verona, Policlinico GB Rossi, Verona, Italy
| | - Enrica Federti
- Department of Medicine, University of Verona, and Azienda Ospedaliera Universitaria Verona, Policlinico GB Rossi, Verona, Italy
| | - Charles Kung
- Agios Pharmaceuticals, Inc., Cambridge, Massachusetts, USA
| | | | | | - Roberta Russo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, and CEINGE Biotecnologie Avanzate, Naples, Italy
| | - Giorgia Federico
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, and CEINGE Biotecnologie Avanzate, Naples, Italy
| | - Francesca Carlomagno
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, and CEINGE Biotecnologie Avanzate, Naples, Italy
| | - Maria Andrea Desbats
- Clinical Genetics Unit, Department of Women and Children's Health, University of Padova, and Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Padova, Italy
| | - Leonardo Salviati
- Clinical Genetics Unit, Department of Women and Children's Health, University of Padova, and Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Padova, Italy
| | - Christophe Leboeuf
- Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Université Paris 7 - Denis Diderot, Paris, France.,AP-HP, Hôpital Saint-Louis, Paris, France
| | - Maria Teresa Valenti
- Department of Medicine, University of Verona, and Azienda Ospedaliera Universitaria Verona, Policlinico GB Rossi, Verona, Italy
| | | | - Anne Janin
- Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Université Paris 7 - Denis Diderot, Paris, France.,AP-HP, Hôpital Saint-Louis, Paris, France
| | - Shaoxia Yu
- Agios Pharmaceuticals, Inc., Cambridge, Massachusetts, USA
| | - Elisabetta Beneduce
- Department of Medicine, University of Verona, and Azienda Ospedaliera Universitaria Verona, Policlinico GB Rossi, Verona, Italy
| | | | - Iana Iatcenko
- Department of Medicine, University of Verona, and Azienda Ospedaliera Universitaria Verona, Policlinico GB Rossi, Verona, Italy
| | - Lenny Dang
- Agios Pharmaceuticals, Inc., Cambridge, Massachusetts, USA
| | - Tomas Ganz
- Department of Medicine, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, USA
| | - Chun-Ling Jung
- Department of Medicine, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, USA
| | - Achille Iolascon
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, and CEINGE Biotecnologie Avanzate, Naples, Italy
| | - Carlo Brugnara
- Department of Laboratory Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Lucia De Franceschi
- Department of Medicine, University of Verona, and Azienda Ospedaliera Universitaria Verona, Policlinico GB Rossi, Verona, Italy
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3
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Preziosi ME, Singh S, Valore EV, Jung CL, Popovic B, Poddar M, Nagarajan S, Ganz T, Monga SP. Mice lacking liver-specific β-catenin develop steatohepatitis and fibrosis after iron overload. J Hepatol 2017; 67:360-369. [PMID: 28341391 PMCID: PMC5515705 DOI: 10.1016/j.jhep.2017.03.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 03/06/2017] [Accepted: 03/13/2017] [Indexed: 12/21/2022]
Abstract
BACKGROUND & AIMS Iron overload disorders such as hereditary hemochromatosis and iron loading anemias are a common cause of morbidity from liver diseases and increase risk of hepatic fibrosis and hepatocellular carcinoma (HCC). Treatment options for iron-induced damage are limited, partly because there is lack of animal models of human disease. Therefore, we investigated the effect of iron overload in liver-specific β-catenin knockout mice (KO), which are susceptible to injury, fibrosis and tumorigenesis following chemical carcinogen exposure. METHODS Iron overload diet was administered to KO and littermate control (CON) mice for various times. To ameliorate an oxidant-mediated component of tissue injury, N-Acetyl-L-(+)-cysteine (NAC) was added to drinking water of mice on iron overload diet. RESULTS KO on iron diet (KO +Fe) exhibited remarkable inflammation, followed by steatosis, oxidative stress, fibrosis, regenerating nodules and occurrence of occasional HCC. Increased injury in KO +Fe was associated with activated protein kinase B (AKT), ERK, and NF-κB, along with reappearance of β-catenin and target gene Cyp2e1, which promoted lipid peroxidation and hepatic damage. Addition of NAC to drinking water protected KO +Fe from hepatic steatosis, injury and fibrosis, and prevented activation of AKT, ERK, NF-κB and reappearance of β-catenin. CONCLUSIONS The absence of hepatic β-catenin predisposes mice to hepatic injury and fibrosis following iron overload, which was reminiscent of hemochromatosis and associated with enhanced steatohepatitis and fibrosis. Disease progression was notably alleviated by antioxidant therapy, which supports its chemopreventive role in the management of chronic iron overload disorders. LAY SUMMARY Lack of animal models for iron overload disorders makes it hard to study the disease process for improving therapies. Feeding high iron diet to mice that lack the β-catenin gene in liver cells led to increased inflammation followed by fat accumulation, cell death and wound healing that mimicked human disease. Administration of an antioxidant prevented hepatic injury in this model.
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Affiliation(s)
- Morgan E. Preziosi
- Department of Pathology (Division of Experimental Pathology),Pittsburgh Liver Research Center
| | - Sucha Singh
- Department of Pathology (Division of Experimental Pathology),Pittsburgh Liver Research Center
| | - Erika V. Valore
- Department of Medicine and Laboratory Medicine, University of California at Los Angeles, Los Angeles, CA,Department of Pathology and Laboratory Medicine, University of California at Los Angeles, Los Angeles, CA
| | - Chun-Ling Jung
- Department of Medicine and Laboratory Medicine, University of California at Los Angeles, Los Angeles, CA,Department of Pathology and Laboratory Medicine, University of California at Los Angeles, Los Angeles, CA
| | | | - Minakshi Poddar
- Department of Pathology (Division of Experimental Pathology),Pittsburgh Liver Research Center
| | - Shanmugam Nagarajan
- Department of Pathology (Division of Experimental Pathology),Pittsburgh Liver Research Center
| | - Tomas Ganz
- Department of Medicine and Laboratory Medicine, University of California at Los Angeles, Los Angeles, CA,Department of Pathology and Laboratory Medicine, University of California at Los Angeles, Los Angeles, CA
| | - Satdarshan P Monga
- Department of Pathology (Division of Experimental Pathology), University of Pittsburgh, Pennsylvania, United States; Pittsburgh Liver Research Center, University of Pittsburgh, Pennsylvania, United States; Department of Medicine (Division of Gastroenterology, Hepatology and Nutrition), University of Pittsburgh, Pennsylvania, United States.
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4
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Khachatoorian R, Riahi R, Ganapathy E, Shao H, Wheatley NM, Sundberg C, Jung CL, Ruchala P, Dasgupta A, Arumugaswami V, Gestwicki JE, French SW. Allosteric heat shock protein 70 inhibitors block hepatitis C virus assembly. Int J Antimicrob Agents 2016; 47:289-96. [PMID: 27013001 DOI: 10.1016/j.ijantimicag.2016.01.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [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: 08/27/2015] [Revised: 01/13/2016] [Accepted: 01/20/2016] [Indexed: 12/12/2022]
Abstract
The human molecular chaperones heat shock protein 70 (Hsp70) and heat shock cognate protein 70 (Hsc70) bind to the hepatitis C viral nonstructural protein 5A (NS5A) and regulate its activity. Specifically, Hsp70 is involved in NS5A-augmented internal ribosomal entry site (IRES)-mediated translation of the viral genome, whilst Hsc70 appears to be primarily important for intracellular infectious virion assembly. To better understand the importance of these two chaperones in the viral life cycle, infected human cells were treated with allosteric Hsp70/Hsc70 inhibitors (AHIs). Treatment with AHIs significantly reduced the production of intracellular virus at concentrations that were non-toxic to human hepatoma Huh7.5 cells. The supernatant of treated cultures was then used to infect naïve cells, revealing that AHIs also lowered levels of secreted virus. In contrast to their effects on virion assembly, AHIs did not impact the stability of NS5A or viral protein translation in IRES assays. These results suggest that Hsc70 plays a particularly important and sensitive role in virion assembly. Indeed, it was found that combination of AHIs with a peptide-based viral translation inhibitor exhibited additive antiviral activity. Together these results suggest that the host Hsc70 is a new antiviral target and that its inhibitors utilise a new mechanism of action.
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Affiliation(s)
- Ronik Khachatoorian
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, CA, USA
| | - Rana Riahi
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, CA, USA
| | - Ekambaram Ganapathy
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, CA, USA
| | - Hao Shao
- Department of Pharmaceutical Chemistry, Institute for Neurodegenerative Diseases, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Nicole M Wheatley
- Doe Institute for Genomics and Proteomics, University of California, Los Angeles (UCLA), Los Angeles, CA, USA
| | - Christopher Sundberg
- Department of Human Genetics, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, CA, USA
| | - Chun-Ling Jung
- Department of Medicine, David Geffen School of Medicine at University of California Los Angeles (UCLA), Los Angeles, CA, USA
| | - Piotr Ruchala
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, CA, USA
| | - Asim Dasgupta
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, CA, USA; Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, CA, USA; UCLA AIDS Institute, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, CA, USA
| | - Vaithilingaraja Arumugaswami
- Department of Surgery, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, CA, USA; Department of Surgery, The Board of Governors Regenerative Medicine Institute at Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Jason E Gestwicki
- Department of Pharmaceutical Chemistry, Institute for Neurodegenerative Diseases, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Samuel W French
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, CA, USA; Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, CA, USA; UCLA AIDS Institute, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, CA, USA.
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5
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Khachatoorian R, Ruchala P, Waring A, Jung CL, Ganapathy E, Wheatley N, Sundberg C, Arumugaswami V, Dasgupta A, French SW. Structural characterization of the HSP70 interaction domain of the hepatitis C viral protein NS5A. Virology 2014; 475:46-55. [PMID: 25462345 DOI: 10.1016/j.virol.2014.10.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [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: 09/08/2014] [Revised: 10/02/2014] [Accepted: 10/15/2014] [Indexed: 12/30/2022]
Abstract
We previously identified the NS5A/HSP70 binding site to be a hairpin moiety at C-terminus of NS5A domain I and showed a corresponding cyclized polyarginine-tagged synthetic peptide (HCV4) significantly blocks virus production. Here, sequence comparison confirmed five residues to be conserved. Based on NS5A domain I crystal structure, Phe171, Val173, and Tyr178 were predicted to form the binding interface. Substitution of Phe171 and Val173 with more hydrophobic unusual amino acids improved peptide antiviral activity and HSP70 binding, while similar substitutions at Tyr178 had a negative effect. Substitution of non-conserved residues with arginines maintained antiviral activity and HSP70 binding and dispensed with polyarginine tag for cellular entry. Peptide cyclization improved antiviral activity and HSP70 binding. The cyclic retro-inverso analog displayed the best antiviral properties. FTIR spectroscopy confirmed a secondary structure consisting of an N-terminal beta-sheet followed by a turn and a C-terminal beta-sheet. These peptides constitute a new class of anti-HCV compounds.
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Affiliation(s)
- Ronik Khachatoorian
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles, California, United States of America
| | - Piotr Ruchala
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at University of California, Los Angeles, California, United States of America
| | - Alan Waring
- Division of Molecular Medicine at the Department of Medicine, Los Angeles County Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Chun-Ling Jung
- Department of Medicine, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
| | - Ekambaram Ganapathy
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles, California, United States of America
| | - Nicole Wheatley
- Molecular Biology Interdepartmental Ph.D. Program (MBIDP), Molecular Biology Institute, David Geffen School of Medicine at University of California, Los Angeles, California, United States of America
- Molecular Biology Institute, David Geffen School of Medicine at University of California, Los Angeles, California, United States of America
| | - Christopher Sundberg
- Department of Human Genetics, David Geffen School of Medicine at University of California, Los Angeles, California, United States of America
| | - Vaithilingaraja Arumugaswami
- Department of Surgery, David Geffen School of Medicine at University of California, Los Angeles, California, United States of America
- Department of Surgery, The Board of Governors Regenerative Medicine Institute at Cedars-Sinai Medical center, Los Angeles, California, United States of America
| | - Asim Dasgupta
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at University of California, Los Angeles, California, United States of America
- Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at University of California, Los Angeles, California, United States of America
- UCLA AIDS Institute, David Geffen School of Medicine at University of California, Los Angeles, California, United States of America
| | - Samuel W French
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles, California, United States of America
- Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at University of California, Los Angeles, California, United States of America
- UCLA AIDS Institute, David Geffen School of Medicine at University of California, Los Angeles, California, United States of America
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6
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Lee SH, Lee JY, Jung CL, Bae IH, Suh KH, Ahn YG, Jin DH, Kim TW, Suh YA, Jang SJ. A novel antagonist to the inhibitors of apoptosis (IAPs) potentiates cell death in EGFR-overexpressing non-small-cell lung cancer cells. Cell Death Dis 2014; 5:e1477. [PMID: 25321484 PMCID: PMC4649530 DOI: 10.1038/cddis.2014.447] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [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: 05/15/2014] [Revised: 09/06/2014] [Accepted: 09/11/2014] [Indexed: 12/25/2022]
Abstract
In the effort to develop an efficient chemotherapy drug for the treatment of non-small-cell lung cancer (NSCLC), we analyzed the anti-tumorigenic effects of a novel small molecule targeting the inhibitor of apoptosis (IAPs), HM90822B, on NSCLC cells. HM90822B efficiently decreased IAP expression, especially that of XIAP and survivin, in several NSCLC cells. Interestingly, cells overexpressing epidermal growth factor receptor (EGFR) due to the mutations were more sensitive to HM90822B, undergoing cell cycle arrest and apoptosis when treated. In xenograft experiments, inoculated EGFR-overexpressing NSCLC cells showed tumor regression when treated with the inhibitor, demonstrating the chemotherapeutic potential of this agent. Mechanistically, decreased levels of EGFR, Akt and phospho-MAPKs were observed in inhibitor-treated PC-9 cells on phosphorylation array and western blotting analysis, indicating that the reagent inhibited cell growth by preventing critical cell survival signaling pathways. In addition, gene-specific knockdown studies against XIAP and/or EGFR further uncovered the involvement of Akt and MAPK pathways in HM90822B-mediated downregulation of NSCLC cell growth. Together, these results support that HM90822B is a promising candidate to be developed as lung tumor chemotherapeutics by targeting oncogenic activities of IAP together with inhibiting cell survival signaling pathways.
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Affiliation(s)
- S-H Lee
- Institute for Innovative Cancer Research, Asan Institute for Life Science, Seoul Asan Medical Center, The University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - J-Y Lee
- Institute for Innovative Cancer Research, Asan Institute for Life Science, Seoul Asan Medical Center, The University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - C L Jung
- Institute for Innovative Cancer Research, Asan Institute for Life Science, Seoul Asan Medical Center, The University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - I H Bae
- Hanmi Research Center, Hanmi Pharm. Co., Ltd., Hwaseong, Gyeonggi-do, Republic of Korea
| | - K H Suh
- Hanmi Research Center, Hanmi Pharm. Co., Ltd., Hwaseong, Gyeonggi-do, Republic of Korea
| | - Y G Ahn
- Hanmi Research Center, Hanmi Pharm. Co., Ltd., Hwaseong, Gyeonggi-do, Republic of Korea
| | - D-H Jin
- Institute for Innovative Cancer Research, Asan Institute for Life Science, Seoul Asan Medical Center, The University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - T W Kim
- 1] Institute for Innovative Cancer Research, Asan Institute for Life Science, Seoul Asan Medical Center, The University of Ulsan College of Medicine, Seoul, Republic of Korea [2] Department of Medicinal Oncology, Seoul Asan Medical Center, The University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Y-A Suh
- Institute for Innovative Cancer Research, Asan Institute for Life Science, Seoul Asan Medical Center, The University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - S J Jang
- 1] Institute for Innovative Cancer Research, Asan Institute for Life Science, Seoul Asan Medical Center, The University of Ulsan College of Medicine, Seoul, Republic of Korea [2] Department of Pathology, Seoul Asan Medical Center, The University of Ulsan College of Medicine, Seoul, Republic of Korea
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7
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Khachatoorian R, Ganapathy E, Ahmadieh Y, Wheatley N, Sundberg C, Jung CL, Arumugaswami V, Raychaudhuri S, Dasgupta A, French SW. The NS5A-binding heat shock proteins HSC70 and HSP70 play distinct roles in the hepatitis C viral life cycle. Virology 2014; 454-455:118-27. [PMID: 24725938 DOI: 10.1016/j.virol.2014.02.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [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: 10/15/2013] [Revised: 11/06/2013] [Accepted: 02/11/2014] [Indexed: 12/21/2022]
Abstract
We previously identified HSP70 and HSC70 in complex with NS5A in a proteomic screen. Here, coimmunoprecipitation studies confirmed NS5A/HSC70 complex formation during infection, and immunofluorescence studies showed NS5A and HSC70 to colocalize. Unlike HSP70, HSC70 knockdown did not decrease viral protein levels. Rather, intracellular infectious virion assembly was significantly impaired by HSC70 knockdown. We also discovered that both HSC70 nucleotide binding and substrate binding domains directly bind NS5A whereas only the HSP70 nucleotide binding domain does. Knockdown of both HSC70 and HSP70 demonstrated an additive reduction in virus production. This data suggests that HSC70 and HSP70 play discrete roles in the viral life cycle. Investigation of these different functions may facilitate developing of novel strategies that target host proteins to treat HCV infection.
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Affiliation(s)
- Ronik Khachatoorian
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America.
| | - Ekambaram Ganapathy
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America.
| | - Yasaman Ahmadieh
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, United States of America.
| | - Nicole Wheatley
- Molecular Biology Interdepartmental Ph.D. Program (MBIDP), Molecular Biology Institute, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; Molecular Biology Institute, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America.
| | - Christopher Sundberg
- Department of Human Genetics, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America.
| | - Chun-Ling Jung
- Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America.
| | - Vaithilingaraja Arumugaswami
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; Department of Surgery, Regenerative Medicine Institute at Cedars-Sinai Medical Center, Los Angeles, CA, United States of America.
| | - Santanu Raychaudhuri
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America.
| | - Asim Dasgupta
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; UCLA AIDS Institute, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America.
| | - Samuel W French
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; UCLA AIDS Institute, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America.
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8
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Micewicz ED, Luong HT, Jung CL, Waring AJ, McBride WH, Ruchala P. Novel dimeric Smac analogs as prospective anticancer agents. Bioorg Med Chem Lett 2014; 24:1452-7. [PMID: 24582479 DOI: 10.1016/j.bmcl.2014.02.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [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] [Received: 11/17/2013] [Revised: 02/05/2014] [Accepted: 02/07/2014] [Indexed: 12/20/2022]
Abstract
A small library of monovalent Smac mimics with general structure NMeAla-Tle-(4R)-4-Benzyl-Pro-Xaa-cysteamide, was synthesized (Xaa=hydrophobic residue). The library was screened in vitro against human breast cancer cell lines MCF-7 and MDA-MB-231, and two most active compounds oligomerized via S-alkylation giving bivalent and trivalent derivatives. The most active bivalent analogue SMAC17-2X was tested in vivo and in physiological conditions (mouse model) it exerted a potent anticancer effect resulting in ∼23.4days of tumor growth delay at 7.5mg/kg dose. Collectively, our findings suggest that bivalent Smac analogs obtained via S-alkylation protocol may be a suitable platform for the development of new anticancer therapeutics.
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Affiliation(s)
- Ewa D Micewicz
- Department of Radiation Oncology, University of California at Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA
| | - Hai T Luong
- Department of Medicine, University of California at Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA
| | - Chun-Ling Jung
- Department of Medicine, University of California at Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA
| | - Alan J Waring
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, 1000 West Carson Street, Torrance, CA 90502, USA; Department of Physiology and Biophysics, University of California Irvine, 1001 Health Sciences Road, Irvine, CA 92697, USA
| | - William H McBride
- Department of Radiation Oncology, University of California at Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA
| | - Piotr Ruchala
- Department of Medicine, University of California at Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA.
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Yount NY, Cohen SE, Kupferwasser D, Waring AJ, Ruchala P, Sharma S, Wasserman K, Jung CL, Yeaman MR. Context mediates antimicrobial efficacy of kinocidin congener peptide RP-1. PLoS One 2011; 6:e26727. [PMID: 22073187 PMCID: PMC3208557 DOI: 10.1371/journal.pone.0026727] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 10/02/2011] [Indexed: 11/21/2022] Open
Abstract
Structure-mechanism relationships are key determinants of host defense peptide efficacy. These relationships are influenced by anatomic, physiologic and microbiologic contexts. Structure-mechanism correlates were assessed for the synthetic peptide RP-1, modeled on microbicidal domains of platelet kinocidins. Antimicrobial efficacies and mechanisms of action against susceptible ((S)) or resistant ((R)) Salmonella typhimurium (ST), Staphylococcus aureus (SA), and Candida albicans (CA) strain pairs were studied at pH 7.5 and 5.5. Although RP-1 was active against all study organisms, it exhibited greater efficacy against bacteria at pH 7.5, but greater efficacy against CA at pH 5.5. RP-1 de-energized SA and CA, but caused hyperpolarization of ST in both pH conditions. However, RP-1 permeabilized ST(S) and CA strains at both pH, whereas permeabilization was modest for ST(R) or SA strain at either pH. Biochemical analysis, molecular modeling, and FTIR spectroscopy data revealed that RP-1 has indistinguishable net charge and backbone trajectories at pH 5.5 and 7.5. Yet, concordant with organism-specific efficacy, surface plasmon resonance, and FTIR, molecular dynamics revealed modest helical order increases but greater RP-1 avidity and penetration of bacterial than eukaryotic lipid systems, particularly at pH 7.5. The present findings suggest that pH- and target-cell lipid contexts influence selective antimicrobial efficacy and mechanisms of RP-1 action. These findings offer new insights into selective antimicrobial efficacy and context-specificity of antimicrobial peptides in host defense, and support design strategies for potent anti-infective peptides with minimal concomitant cytotoxicity.
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Affiliation(s)
- Nannette Y. Yount
- Division of Infectious Diseases, Los Angeles County-Harbor University of California Los Angeles Medical Center, Torrance, California, United States of America
- Los Angeles Biomedical Research Institute at Harbor-University of California Los Angeles Medical Center, Torrance, California, United States of America
| | - Samuel E. Cohen
- Division of Infectious Diseases, Los Angeles County-Harbor University of California Los Angeles Medical Center, Torrance, California, United States of America
- Los Angeles Biomedical Research Institute at Harbor-University of California Los Angeles Medical Center, Torrance, California, United States of America
- School of Medicine, University of California Irvine, Irvine, California, United States of America
| | - Deborah Kupferwasser
- Division of Infectious Diseases, Los Angeles County-Harbor University of California Los Angeles Medical Center, Torrance, California, United States of America
- Los Angeles Biomedical Research Institute at Harbor-University of California Los Angeles Medical Center, Torrance, California, United States of America
| | - Alan J. Waring
- Los Angeles Biomedical Research Institute at Harbor-University of California Los Angeles Medical Center, Torrance, California, United States of America
- Department of Medicine, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
- Department of Physiology and Biophysics, School of Medicine, University of California Irvine, Irvine, California, United States of America
- Division of Molecular Medicine, Los Angeles County-Harbor University of California Los Angeles Medical Center, Torrance, California, United States of America
| | - Piotr Ruchala
- Department of Medicine, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
| | - Shantanu Sharma
- Materials and Process Simulation Center, California Institute of Technology, Pasadena, California, United States of America
| | - Karlman Wasserman
- Los Angeles Biomedical Research Institute at Harbor-University of California Los Angeles Medical Center, Torrance, California, United States of America
- Division of Pulmonary / Critical Care Medicine, Los Angeles County-Harbor University of California Los Angeles Medical Center, Torrance, California, United States of America
| | - Chun-Ling Jung
- Department of Medicine, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
| | - Michael R. Yeaman
- Division of Infectious Diseases, Los Angeles County-Harbor University of California Los Angeles Medical Center, Torrance, California, United States of America
- Los Angeles Biomedical Research Institute at Harbor-University of California Los Angeles Medical Center, Torrance, California, United States of America
- Department of Medicine, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
- Division of Molecular Medicine, Los Angeles County-Harbor University of California Los Angeles Medical Center, Torrance, California, United States of America
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Ruchala P, Cho S, Cole AL, Carpenter C, Jung CL, Luong H, Micewicz ED, Waring AJ, Cole AM, Herold BC, Lehrer RI. Simplified θ-Defensins: Search for New Antivirals. Int J Pept Res Ther 2011. [DOI: 10.1007/s10989-011-9272-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Micewicz ED, Cole AL, Jung CL, Luong H, Phillips ML, Pratikhya P, Sharma S, Waring AJ, Cole AM, Ruchala P. Grifonin-1: a small HIV-1 entry inhibitor derived from the algal lectin, Griffithsin. PLoS One 2010; 5:e14360. [PMID: 21179548 PMCID: PMC3002932 DOI: 10.1371/journal.pone.0014360] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 11/22/2010] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Griffithsin, a 121-residue protein isolated from a red algal Griffithsia sp., binds high mannose N-linked glycans of virus surface glycoproteins with extremely high affinity, a property that allows it to prevent the entry of primary isolates and laboratory strains of T- and M-tropic HIV-1. We used the sequence of a portion of griffithsin's sequence as a design template to create smaller peptides with antiviral and carbohydrate-binding properties. METHODOLOGY/RESULTS The new peptides derived from a trio of homologous β-sheet repeats that comprise the motifs responsible for its biological activity. Our most active antiviral peptide, grifonin-1 (GRFN-1), had an EC50 of 190.8±11.0 nM in in vitro TZM-bl assays and an EC(50) of 546.6±66.1 nM in p24gag antigen release assays. GRFN-1 showed considerable structural plasticity, assuming different conformations in solvents that differed in polarity and hydrophobicity. Higher concentrations of GRFN-1 formed oligomers, based on intermolecular β-sheet interactions. Like its parent protein, GRFN-1 bound viral glycoproteins gp41 and gp120 via the N-linked glycans on their surface. CONCLUSION Its substantial antiviral activity and low toxicity in vitro suggest that GRFN-1 and/or its derivatives may have therapeutic potential as topical and/or systemic agents directed against HIV-1.
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Affiliation(s)
- Ewa D. Micewicz
- Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, United States of America
- Department of Radiation Oncology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Amy L. Cole
- Department of Molecular Biology and Microbiology, Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
| | - Chun-Ling Jung
- Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Hai Luong
- Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Martin L. Phillips
- Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Pratikhya Pratikhya
- Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Shantanu Sharma
- Materials and Process Simulation Center, California Institute of Technology, Pasadena, California, United States of America
| | - Alan J. Waring
- Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Alexander M. Cole
- Department of Molecular Biology and Microbiology, Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
| | - Piotr Ruchala
- Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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12
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Walther FJ, Waring AJ, Hernandez-Juviel JM, Gordon LM, Wang Z, Jung CL, Ruchala P, Clark AP, Smith WM, Sharma S, Notter RH. Critical structural and functional roles for the N-terminal insertion sequence in surfactant protein B analogs. PLoS One 2010; 5:e8672. [PMID: 20084172 PMCID: PMC2805716 DOI: 10.1371/journal.pone.0008672] [Citation(s) in RCA: 43] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Accepted: 12/18/2009] [Indexed: 01/14/2023] Open
Abstract
Background Surfactant protein B (SP-B; 79 residues) belongs to the saposin protein superfamily, and plays functional roles in lung surfactant. The disulfide cross-linked, N- and C-terminal domains of SP-B have been theoretically predicted to fold as charged, amphipathic helices, suggesting their participation in surfactant activities. Earlier structural studies with Mini-B, a disulfide-linked construct based on the N- and C-terminal regions of SP-B (i.e., ∼residues 8–25 and 63–78), confirmed that these neighboring domains are helical; moreover, Mini-B retains critical in vitro and in vivo surfactant functions of the native protein. Here, we perform similar analyses on a Super Mini-B construct that has native SP-B residues (1–7) attached to the N-terminus of Mini-B, to test whether the N-terminal sequence is also involved in surfactant activity. Methodology/Results FTIR spectra of Mini-B and Super Mini-B in either lipids or lipid-mimics indicated that these peptides share similar conformations, with primary α-helix and secondary β-sheet and loop-turns. Gel electrophoresis demonstrated that Super Mini-B was dimeric in SDS detergent-polyacrylamide, while Mini-B was monomeric. Surface plasmon resonance (SPR), predictive aggregation algorithms, and molecular dynamics (MD) and docking simulations further suggested a preliminary model for dimeric Super Mini-B, in which monomers self-associate to form a dimer peptide with a “saposin-like” fold. Similar to native SP-B, both Mini-B and Super Mini-B exhibit in vitro activity with spread films showing near-zero minimum surface tension during cycling using captive bubble surfactometry. In vivo, Super Mini-B demonstrates oxygenation and dynamic compliance that are greater than Mini-B and compare favorably to full-length SP-B. Conclusion Super Mini-B shows enhanced surfactant activity, probably due to the self-assembly of monomer peptide into dimer Super Mini-B that mimics the functions and putative structure of native SP-B.
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Affiliation(s)
- Frans J Walther
- Los Angeles Biomedical Research Institute at Harbor, University of California Los Angeles Medical Center, Torrance, California, USA.
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13
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Stenger PC, Alonso C, Zasadzinski JA, Waring AJ, Jung CL, Pinkerton KE. Environmental tobacco smoke effects on lung surfactant film organization. Biochim Biophys Acta 2008; 1788:358-70. [PMID: 19118518 DOI: 10.1016/j.bbamem.2008.11.021] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 11/13/2008] [Accepted: 11/14/2008] [Indexed: 01/05/2023]
Abstract
Adsorption of the clinical lung surfactants (LS) Curosurf or Survanta from aqueous suspension to the air-water interface progresses from multi-bilayer aggregates through multilayer films to a coexistence between multilayer and monolayer domains. Exposure to environmental tobacco smoke (ETS) alters this progression as shown by Langmuir isotherms, fluorescence microscopy and atomic force microscopy (AFM). After 12 h of LS exposure to ETS, AFM images of Langmuir-Blodgett deposited films show that ETS reduces the amount of material near the interface and alters how surfactant is removed from the interface during compression. For Curosurf, ETS prevents refining of the film composition during cycling; this leads to higher minimum surface tensions. ETS also changes the morphology of the Curosurf film by reducing the size of condensed phase domains from 8-12 microm to approximately 2 microm, suggesting a decrease in the line tension between the domains. The minimum surface tension and morphology of the Survanta film are less impacted by ETS exposure, although the amount of material associated with the film is reduced in a similar way to Curosurf. Fluorescence and mass spectra of Survanta dispersions containing native bovine SP-B treated with ETS indicate the oxidative degradation of protein aromatic amino acid residue side chains. Native bovine SP-C isolated from ETS exposed Survanta had changes in molecular mass consistent with deacylation of the lipoprotein. Fourier Transform Infrared Spectroscopy (FTIR) characterization of the hydrophobic proteins from ETS treated Survanta dispersions show significant changes in the conformation of SP-B and SP-C that correlate with the altered surface activity and morphology of the lipid-protein film.
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Affiliation(s)
- Patrick C Stenger
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106-5080, USA
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14
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Van Lenten BJ, Wagner AC, Jung CL, Ruchala P, Waring AJ, Lehrer RI, Watson AD, Hama S, Navab M, Anantharamaiah GM, Fogelman AM. Anti-inflammatory apoA-I-mimetic peptides bind oxidized lipids with much higher affinity than human apoA-I. J Lipid Res 2008; 49:2302-11. [PMID: 18621920 DOI: 10.1194/jlr.m800075-jlr200] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
4F is an anti-inflammatory, apolipoprotein A-I (apoA-I)-mimetic peptide that is active in vivo at nanomolar concentrations in the presence of a large molar excess of apoA-I. Physiologic concentrations ( approximately 35 microM) of human apoA-I did not inhibit the production of LDL-induced monocyte chemotactic activity by human aortic endothelial cell cultures, but adding nanomolar concentrations of 4F in the presence of approximately 35 microM apoA-I significantly reduced this inflammatory response. We analyzed lipid binding by surface plasmon resonance. The anti-inflammatory 4F peptide bound oxidized lipids with much higher affinity than did apoA-I. Initially, we examined the binding of PAPC (1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphatidylcholine) and observed that its oxidized products bound 4F with an affinity that was approximately 4-6 orders of magnitude higher than that of apoA-I. This high binding affinity was confirmed in studies with defined lipids and phospholipids. 3F-2 and 3F(14) are also amphipathic alpha-helical octadecapeptides, but 3F-2 inhibits atherosclerosis in mice and 3F(14) does not. Like 4F, 3F-2 also bound oxidized phospholipids with very high affinity, whereas 3F(14) resembled apoA-I. The extraordinary ability of 4F to bind pro-inflammatory oxidized lipids probably accounts for its remarkable anti-inflammatory properties.
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Affiliation(s)
- Brian J Van Lenten
- Department of Medicine David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1679, USA.
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15
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Gordon LM, Nisthal A, Lee AB, Eskandari S, Ruchala P, Jung CL, Waring AJ, Mobley PW. Structural and functional properties of peptides based on the N-terminus of HIV-1 gp41 and the C-terminus of the amyloid-beta protein. Biochim Biophys Acta 2008; 1778:2127-37. [PMID: 18515070 DOI: 10.1016/j.bbamem.2008.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 04/07/2008] [Accepted: 05/06/2008] [Indexed: 11/30/2022]
Abstract
Given their high alanine and glycine levels, plaque formation, alpha-helix to beta-sheet interconversion and fusogenicity, FP (i.e., the N-terminal fusion peptide of HIV-1 gp41; 23 residues) and amyloids were proposed as belonging to the same protein superfamily. Here, we further test whether FP may exhibit 'amyloid-like' characteristics, by contrasting its structural and functional properties with those of Abeta(26-42), a 17-residue peptide from the C-terminus of the amyloid-beta protein responsible for Alzheimer's. FTIR spectroscopy, electron microscopy, light scattering and predicted amyloid structure aggregation (PASTA) indicated that aqueous FP and Abeta(26-42) formed similar networked beta-sheet fibrils, although the FP fibril interactions were weaker. FP and Abeta(26-42) both lysed and aggregated human erythrocytes, with the hemolysis-onsets correlated with the conversion of alpha-helix to beta-sheet for each peptide in liposomes. Congo red (CR), a marker of amyloid plaques in situ, similarly inhibited either FP- or Abeta(26-42)-induced hemolysis, and surface plasmon resonance indicated that this may be due to direct CR-peptide binding. These findings suggest that membrane-bound beta-sheets of FP may contribute to the cytopathicity of HIV in vivo through an amyloid-type mechanism, and support the classification of HIV-1 FP as an 'amyloid homolog' (or 'amylog').
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Affiliation(s)
- Larry M Gordon
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
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16
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Walther FJ, Waring AJ, Hernandez-Juviel JM, Gordon LM, Schwan AL, Jung CL, Chang Y, Wang Z, Notter RH. Dynamic surface activity of a fully synthetic phospholipase-resistant lipid/peptide lung surfactant. PLoS One 2007; 2:e1039. [PMID: 17940603 PMCID: PMC2013942 DOI: 10.1371/journal.pone.0001039] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Accepted: 09/20/2007] [Indexed: 11/18/2022] Open
Abstract
Background This study examines the surface activity and resistance to phospholipase degradation of a fully-synthetic lung surfactant containing a novel diether phosphonolipid (DEPN-8) plus a 34 amino acid peptide (Mini-B) related to native surfactant protein (SP)-B. Activity studies used adsorption, pulsating bubble, and captive bubble methods to assess a range of surface behaviors, supplemented by molecular studies using Fourier transform infrared (FTIR) spectroscopy, circular dichroism (CD), and plasmon resonance. Calf lung surfactant extract (CLSE) was used as a positive control. Results DEPN-8+1.5% (by wt.) Mini-B was fully resistant to degradation by phospholipase A2 (PLA2) in vitro, while CLSE was severely degraded by this enzyme. Mini-B interacted with DEPN-8 at the molecular level based on FTIR spectroscopy, and had significant plasmon resonance binding affinity for DEPN-8. DEPN-8+1.5% Mini-B had greatly increased adsorption compared to DEPN-8 alone, but did not fully equal the very high adsorption of CLSE. In pulsating bubble studies at a low phospholipid concentration of 0.5 mg/ml, DEPN-8+1.5% Mini-B and CLSE both reached minimum surface tensions <1 mN/m after 10 min of cycling. DEPN-8 (2.5 mg/ml)+1.5% Mini-B and CLSE (2.5 mg/ml) also reached minimum surface tensions <1 mN/m at 10 min of pulsation in the presence of serum albumin (3 mg/ml) on the pulsating bubble. In captive bubble studies, DEPN-8+1.5% Mini-B and CLSE both generated minimum surface tensions <1 mN/m on 10 successive cycles of compression/expansion at quasi-static and dynamic rates. Conclusions These results show that DEPN-8 and 1.5% Mini-B form an interactive binary molecular mixture with very high surface activity and the ability to resist degradation by phospholipases in inflammatory lung injury. These characteristics are promising for the development of related fully-synthetic lipid/peptide exogenous surfactants for treating diseases of surfactant deficiency or dysfunction.
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Affiliation(s)
- Frans J Walther
- Los Angeles Biomedical Research Institute, Harbor-University of California at Los Angeles Medical Center, Torrance, California, United States of America.
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Nemeth E, Preza GC, Jung CL, Kaplan J, Waring AJ, Ganz T. The N-terminus of hepcidin is essential for its interaction with ferroportin: structure-function study. Blood 2005; 107:328-33. [PMID: 16141345 PMCID: PMC1895343 DOI: 10.1182/blood-2005-05-2049] [Citation(s) in RCA: 188] [Impact Index Per Article: 9.9] [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: 12/19/2022] Open
Abstract
Hepcidin is the principal iron-regulatory hormone. It acts by binding to the iron exporter ferroportin, inducing its internalization and degradation, thereby blocking cellular iron efflux. The bioactive 25 amino acid (aa) peptide has a hairpin structure stabilized by 4 disulfide bonds. We synthesized a series of hepcidin derivatives and determined their bioactivity in a cell line expressing ferroportin-GFP fusion protein, by measuring the degradation of ferroportin-GFP and the accumulation of ferritin after peptide treatment. Bioactivity was also assayed in mice by the induction of hypoferremia. Serial deletion of N-terminal amino acids caused progressive decrease in activity which was completely lost when 5 N-terminal aa's were deleted. Synthetic 3-aa and 6-aa N-terminal peptides alone, however, did not internalize ferroportin and did not interfere with ferroportin internalization by native hepcidin. Deletion of 2 C-terminal aa's did not affect peptide activity. Removal of individual disulfide bonds by pairwise substitution of cysteines with alanines also did not affect peptide activity in vitro. However, these peptides were less active in vivo, likely because of their decreased stability in circulation. G71D and K83R, substitutions previously described in humans, did not affect hepcidin activity. Apart from the essential nature of the N-terminus, hepcidin structure appears permissive for mutations.
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Affiliation(s)
- Elizabeta Nemeth
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1690, USA
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