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Huck BC, Thiyagarajan D, Bali A, Boese A, Besecke KFW, Hozsa C, Gieseler RK, Furch M, Carvalho‐Wodarz C, Waldow F, Schwudke D, Metelkina O, Titz A, Huwer H, Schwarzkopf K, Hoppstädter J, Kiemer AK, Koch M, Loretz B, Lehr C. Nano-in-Microparticles for Aerosol Delivery of Antibiotic-Loaded, Fucose-Derivatized, and Macrophage-Targeted Liposomes to Combat Mycobacterial Infections: In Vitro Deposition, Pulmonary Barrier Interactions, and Targeted Delivery. Adv Healthc Mater 2022; 11:e2102117. [PMID: 35112802 DOI: 10.1002/adhm.202102117] [Citation(s) in RCA: 5] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 01/14/2022] [Indexed: 12/12/2022]
Abstract
Nontuberculous mycobacterial infections rapidly emerge and demand potent medications to cope with resistance. In this context, targeted loco-regional delivery of aerosol medicines to the lungs is an advantage. However, sufficient antibiotic delivery requires engineered aerosols for optimized deposition. Here, the effect of bedaquiline-encapsulating fucosylated versus nonfucosylated liposomes on cellular uptake and delivery is investigated. Notably, this comparison includes critical parameters for pulmonary delivery, i.e., aerosol deposition and the noncellular barriers of pulmonary surfactant (PS) and mucus. Targeting increases liposomal uptake into THP-1 cells as well as peripheral blood monocyte- and lung-tissue derived macrophages. Aerosol deposition in the presence of PS, however, masks the effect of active targeting. PS alters antibiotic release that depends on the drug's hydrophobicity, while mucus reduces the mobility of nontargeted more than fucosylated liposomes. Dry-powder microparticles of spray-dried bedaquiline-loaded liposomes display a high fine particle fraction of >70%, as well as preserved liposomal integrity and targeting function. The antibiotic effect is maintained when deposited as powder aerosol on cultured Mycobacterium abscessus. When treating M. abscessus infected THP-1 cells, the fucosylated variant enabled enhanced bacterial killing, thus opening up a clear perspective for the improved treatment of nontuberculous mycobacterial infections.
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Affiliation(s)
- Benedikt C. Huck
- Department of Drug Delivery Helmholtz Institute for Pharmaceutical Research Saarland Campus E8.1 Saarbrücken 66123 Germany
- Department of Pharmacy Helmholtz Institute for Pharmaceutical Research Saarland Saarland University Campus E8 1 Saarbrücken 66123 Germany
| | - Durairaj Thiyagarajan
- Department of Anti‐infective Drug Discovery Helmholtz Institute for Pharmaceutical Research Saarland Campus E8 1 Saarbrücken 66123 Germany
| | - Aghiad Bali
- Department of Drug Delivery Helmholtz Institute for Pharmaceutical Research Saarland Campus E8.1 Saarbrücken 66123 Germany
- Department of Pharmacy Helmholtz Institute for Pharmaceutical Research Saarland Saarland University Campus E8 1 Saarbrücken 66123 Germany
| | - Annette Boese
- Department of Drug Delivery Helmholtz Institute for Pharmaceutical Research Saarland Campus E8.1 Saarbrücken 66123 Germany
| | | | | | - Robert K. Gieseler
- Rodos Biotarget GmbH Hannover 30625 Germany
- Laboratory of Immunology and Molecular Biology and Department of Internal Medicine University Hospital Knappschaftskrankenhaus Bochum Ruhr University Bochum Bochum 44892 Germany
| | | | - Cristiane Carvalho‐Wodarz
- Department of Drug Delivery Helmholtz Institute for Pharmaceutical Research Saarland Campus E8.1 Saarbrücken 66123 Germany
| | - Franziska Waldow
- Research Center Borstel Leibniz Lung Center Borstel 23845 Germany
- German Center for Infection Research Thematic Translational Unit Tuberculosis Partner Site Hamburg‐Lübeck‐Borstel‐Riems Braunschweig 38124 Germany
| | - Dominik Schwudke
- Research Center Borstel Leibniz Lung Center Borstel 23845 Germany
- German Center for Infection Research Thematic Translational Unit Tuberculosis Partner Site Hamburg‐Lübeck‐Borstel‐Riems Braunschweig 38124 Germany
- German Center for Lung Research (DZL) Airway Research Center North (ARCN) Kiel Nano Surface and Interface Science KiNSIS Kiel University Kiel 24118 Germany
| | - Olga Metelkina
- Chemical Biology of Carbohydrates (CBCH) Helmholtz‐Institute for Pharmaceutical Research Saarland (HIPS) Helmholtz Center for Infection Research Saarbrücken 66123 Germany
- Department of Chemistry Saarland University Saarbrücken 66123 Germany
| | - Alexander Titz
- Chemical Biology of Carbohydrates (CBCH) Helmholtz‐Institute for Pharmaceutical Research Saarland (HIPS) Helmholtz Center for Infection Research Saarbrücken 66123 Germany
- Department of Chemistry Saarland University Saarbrücken 66123 Germany
- Deutsches Zentrum für Infektionsforschung (DZIF) Hannover‐Braunschweig site Braunschweig 38124 Germany
| | - Hanno Huwer
- Cardiothoracic Surgery Heart Center Voelklingen Völklingen 66333 Germany
| | - Konrad Schwarzkopf
- Department of Anaesthesia and Intensive Care Klinikum Saarbrücken gGmbH Saarbrücken 66119 Germany
| | - Jessica Hoppstädter
- Pharmaceutical Biology Saarland University Campus C2 3 Saarbrücken 66123 Germany
| | - Alexandra K. Kiemer
- Pharmaceutical Biology Saarland University Campus C2 3 Saarbrücken 66123 Germany
| | - Marcus Koch
- INM – Leibniz Institute for New Materials Campus D2 2 Saarbrücken 66123 Germany
| | - Brigitta Loretz
- Department of Drug Delivery Helmholtz Institute for Pharmaceutical Research Saarland Campus E8.1 Saarbrücken 66123 Germany
| | - Claus‐Michael Lehr
- Department of Drug Delivery Helmholtz Institute for Pharmaceutical Research Saarland Campus E8.1 Saarbrücken 66123 Germany
- Department of Pharmacy Helmholtz Institute for Pharmaceutical Research Saarland Saarland University Campus E8 1 Saarbrücken 66123 Germany
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Polyak A, Bankstahl JP, Besecke KFW, Hozsa C, Triebert W, Pannem RR, Manstein F, Borcholte T, Furch M, Zweigerdt R, Gieseler RK, Bengel FM, Ross TL. Simplified 89Zr-Labeling Protocol of Oxine (8-Hydroxyquinoline) Enabling Prolonged Tracking of Liposome-Based Nanomedicines and Cells. Pharmaceutics 2021; 13:pharmaceutics13071097. [PMID: 34371788 PMCID: PMC8309181 DOI: 10.3390/pharmaceutics13071097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 07/07/2021] [Accepted: 07/14/2021] [Indexed: 01/11/2023] Open
Abstract
In this work, a method for the preparation of the highly lipophilic labeling synthon [89Zr]Zr(oxinate)4 was optimized for the radiolabeling of liposomes and human induced pluripotent stem cells (hiPSCs). The aim was to establish a robust and reliable labeling protocol for enabling up to one week positron emission tomography (PET) tracing of lipid-based nanomedicines and transplanted or injected cells, respectively. [89Zr]Zr(oxinate)4 was prepared from oxine (8-hydroxyquinoline) and [89Zr]Zr(OH)2(C2O4). Earlier introduced liquid-liquid extraction methods were simplified by the optimization of buffering, pH, temperature and reaction times. For quality control, thin-layer chromatography (TLC), size-exclusion chromatography (SEC) and centrifugation were employed. Subsequently, the 89Zr-complex was incorporated into liposome formulations. PET/CT imaging of 89Zr-labeled liposomes was performed in healthy mice. Cell labeling was accomplished in PBS using suspensions of 3 × 106 hiPSCs, each. [89Zr]Zr(oxinate)4 was synthesized in very high radiochemical yields of 98.7% (96.8% ± 2.8%). Similarly, high internalization rates (≥90%) of [89Zr]Zr(oxinate)4 into liposomes were obtained over an 18 h incubation period. MicroPET and biodistribution studies confirmed the labeled nanocarriers' in vivo stability. Human iPSCs incorporated the labeling agent within 30 min with ~50% efficiency. Prolonged PET imaging is an ideal tool in the development of lipid-based nanocarriers for drug delivery and cell therapies. To this end, a reliable and reproducible 89Zr radiolabeling method was developed and tested successfully in a model liposome system and in hiPSCs alike.
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Affiliation(s)
- Andras Polyak
- Department of Nuclear Medicine, Hannover Medical School, 30625 Hannover, Germany; (J.P.B.); (F.M.B.); (T.L.R.)
- Correspondence:
| | - Jens P. Bankstahl
- Department of Nuclear Medicine, Hannover Medical School, 30625 Hannover, Germany; (J.P.B.); (F.M.B.); (T.L.R.)
| | - Karen F. W. Besecke
- Rodos Biotarget GmbH, Medical Park Hannover, 30625 Hannover, Germany; (K.F.W.B.); (C.H.); (R.R.P.); (T.B.); (M.F.); (R.K.G.)
- SolMic BioTech GmbH, 40225 Düsseldorf, Germany
| | - Constantin Hozsa
- Rodos Biotarget GmbH, Medical Park Hannover, 30625 Hannover, Germany; (K.F.W.B.); (C.H.); (R.R.P.); (T.B.); (M.F.); (R.K.G.)
| | - Wiebke Triebert
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), 30625 Hannover, Germany; (W.T.); (F.M.); (R.Z.)
- Department of Cardiac, Thoracic, Transplantation and Vascular Surgery (HTTG), Hannover Medical School, 30625 Hannover, Germany
| | - Rajeswara Rao Pannem
- Rodos Biotarget GmbH, Medical Park Hannover, 30625 Hannover, Germany; (K.F.W.B.); (C.H.); (R.R.P.); (T.B.); (M.F.); (R.K.G.)
- Bioloving GmbH & Co KG, 69126 Heidelberg, Germany
| | - Felix Manstein
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), 30625 Hannover, Germany; (W.T.); (F.M.); (R.Z.)
- Department of Cardiac, Thoracic, Transplantation and Vascular Surgery (HTTG), Hannover Medical School, 30625 Hannover, Germany
| | - Thomas Borcholte
- Rodos Biotarget GmbH, Medical Park Hannover, 30625 Hannover, Germany; (K.F.W.B.); (C.H.); (R.R.P.); (T.B.); (M.F.); (R.K.G.)
| | - Marcus Furch
- Rodos Biotarget GmbH, Medical Park Hannover, 30625 Hannover, Germany; (K.F.W.B.); (C.H.); (R.R.P.); (T.B.); (M.F.); (R.K.G.)
- SolMic BioTech GmbH, 40225 Düsseldorf, Germany
- Bioloving GmbH & Co KG, 69126 Heidelberg, Germany
| | - Robert Zweigerdt
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), 30625 Hannover, Germany; (W.T.); (F.M.); (R.Z.)
- Department of Cardiac, Thoracic, Transplantation and Vascular Surgery (HTTG), Hannover Medical School, 30625 Hannover, Germany
| | - Robert K. Gieseler
- Rodos Biotarget GmbH, Medical Park Hannover, 30625 Hannover, Germany; (K.F.W.B.); (C.H.); (R.R.P.); (T.B.); (M.F.); (R.K.G.)
- Department of Internal Medicine, and Laboratory of Immunology & Molecular Biology, University Hospital, Knappschaftskrankenhaus, Ruhr University Bochum, 44801 Bochum, Germany
| | - Frank M. Bengel
- Department of Nuclear Medicine, Hannover Medical School, 30625 Hannover, Germany; (J.P.B.); (F.M.B.); (T.L.R.)
| | - Tobias L. Ross
- Department of Nuclear Medicine, Hannover Medical School, 30625 Hannover, Germany; (J.P.B.); (F.M.B.); (T.L.R.)
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3
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Thiyagarajan D, Huck B, Nothdurft B, Koch M, Rudolph D, Rutschmann M, Feldmann C, Hozsa C, Furch M, Besecke KFW, Gieseler RK, Loretz B, Lehr CM. Spray-dried lactose-leucine microparticles for pulmonary delivery of antimycobacterial nanopharmaceuticals. Drug Deliv Transl Res 2021; 11:1766-1778. [PMID: 34101127 PMCID: PMC8236044 DOI: 10.1007/s13346-021-01011-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2021] [Indexed: 12/20/2022]
Abstract
Pulmonary delivery of nanocarriers for novel antimycobacterial compounds is challenging because the aerodynamic properties of nanomaterials are sub-optimal for such purposes. Here, we report the development of dry powder formulations for nanocarriers containing benzothiazinone 043 (BTZ) or levofloxacin (LVX), respectively. The intricacy is to generate dry powder aerosols with adequate aerodynamic properties while maintaining both nanostructural integrity and compound activity until reaching the deeper lung compartments. Microparticles (MPs) were prepared using vibrating mesh spray drying with lactose and leucine as approved excipients for oral inhalation drug products. MP morphologies and sizes were measured using various biophysical techniques including determination of geometric and aerodynamic mean sizes, X-ray diffraction, and confocal and focused ion beam scanning electron microscopy. Differences in the nanocarriers’ characteristics influenced the MPs’ sizes and shapes, their aerodynamic properties, and, hence, also the fraction available for lung deposition. Spay-dried powders of a BTZ nanosuspension, BTZ-loaded silica nanoparticles (NPs), and LVX-loaded liposomes showed promising respirable fractions, in contrast to zirconyl hydrogen phosphate nanocontainers. While the colloidal stability of silica NPs was improved after spray drying, MPs encapsulating either BTZ nanosuspensions or LVX-loaded liposomes showed the highest respirable fractions and active pharmaceutical ingredient loads. Importantly, for the BTZ nanosuspension, biocompatibility and in vitro uptake by a macrophage model cell line were improved even further after spray drying. ![]()
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Affiliation(s)
- Durairaj Thiyagarajan
- Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Center for Infection Research (HZI), Campus E8.1, 66123, Saarbrucken, Germany
| | - Benedikt Huck
- Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Center for Infection Research (HZI), Campus E8.1, 66123, Saarbrucken, Germany.,Department of Pharmacy, Saarland University, 66123, Saarbrucken, Germany
| | - Birgit Nothdurft
- , INM - Leibniz Institute for New Materials, Campus D2 2, 66123, Saarbrucken, Germany
| | - Marcus Koch
- , INM - Leibniz Institute for New Materials, Campus D2 2, 66123, Saarbrucken, Germany
| | - David Rudolph
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131, Karlsruhe, Germany
| | - Mark Rutschmann
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131, Karlsruhe, Germany
| | - Claus Feldmann
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131, Karlsruhe, Germany
| | - Constantin Hozsa
- Rodos Biotarget GmbH, Feodor-Lynen-Str. 31, 30625, Hannover, Germany.,Siegfried AG Hameln, 31789, Hameln, Germany
| | - Marcus Furch
- Rodos Biotarget GmbH, Feodor-Lynen-Str. 31, 30625, Hannover, Germany.,Biolife Holding GmbH & Co. KG, 69126, Heidelberg, Germany
| | - Karen F W Besecke
- Rodos Biotarget GmbH, Feodor-Lynen-Str. 31, 30625, Hannover, Germany
| | - Robert K Gieseler
- Rodos Biotarget GmbH, Feodor-Lynen-Str. 31, 30625, Hannover, Germany.,Department of Medicine, University Hospital Bochum, 44892, Bochum, Germany
| | - Brigitta Loretz
- Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Center for Infection Research (HZI), Campus E8.1, 66123, Saarbrucken, Germany.
| | - Claus-Michael Lehr
- Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Center for Infection Research (HZI), Campus E8.1, 66123, Saarbrucken, Germany.,Department of Pharmacy, Saarland University, 66123, Saarbrucken, Germany
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4
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Durán V, Grabski E, Hozsa C, Becker J, Yasar H, Monteiro JT, Costa B, Koller N, Lueder Y, Wiegmann B, Brandes G, Kaever V, Lehr CM, Lepenies B, Tampé R, Förster R, Bošnjak B, Furch M, Graalmann T, Kalinke U. Fucosylated lipid nanocarriers loaded with antibiotics efficiently inhibit mycobacterial propagation in human myeloid cells. J Control Release 2021; 334:201-212. [PMID: 33865899 DOI: 10.1016/j.jconrel.2021.04.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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: 08/21/2020] [Revised: 04/10/2021] [Accepted: 04/12/2021] [Indexed: 12/13/2022]
Abstract
Antibiotic treatment of tuberculosis (TB) is complex, lengthy, and can be associated with various adverse effects. As a result, patient compliance often is poor, thus further enhancing the risk of selecting multi-drug resistant bacteria. Macrophage mannose receptor (MMR)-positive alveolar macrophages (AM) constitute a niche in which Mycobacterium tuberculosis replicates and survives. Therefore, we encapsulated levofloxacin in lipid nanocarriers functionalized with fucosyl residues that interact with the MMR. Indeed, such nanocarriers preferentially targeted MMR-positive myeloid cells, and in particular, AM. Intracellularly, fucosylated lipid nanocarriers favorably delivered their payload into endosomal compartments, where mycobacteria reside. In an in vitro setting using infected human primary macrophages as well as dendritic cells, the encapsulated antibiotic cleared the pathogen more efficiently than free levofloxacin. In conclusion, our results point towards carbohydrate-functionalized nanocarriers as a promising tool for improving TB treatment by targeted delivery of antibiotics.
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Affiliation(s)
- Verónica Durán
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany
| | - Elena Grabski
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany
| | | | - Jennifer Becker
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany
| | - Hanzey Yasar
- Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Center for Infection Research (HZI), Department of Drug Delivery (DDEL), Saarbrücken, Germany
| | - João T Monteiro
- Institute for Immunology & Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Hannover, Germany
| | - Bibiana Costa
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany
| | - Nicole Koller
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt, Germany
| | - Yvonne Lueder
- Institute of Immunology, Hannover Medical School, Hannover, Germany
| | - Bettina Wiegmann
- Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany.; Lower Saxony Center for Biomedical Engineering, Implant Research and Development, Hannover, Medical School, Germany; German Centre of Lung Research, 30625, Hannover, Germany
| | - Gudrun Brandes
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany
| | - Volkhard Kaever
- Institute of Pharmacology, Hannover Medical School, Hannover, Germany
| | - Claus-Michael Lehr
- Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Center for Infection Research (HZI), Department of Drug Delivery (DDEL), Saarbrücken, Germany
| | - Bernd Lepenies
- Institute for Immunology & Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Hannover, Germany
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt, Germany
| | - Reinhold Förster
- Institute of Immunology, Hannover Medical School, Hannover, Germany.; Cluster of Excellence - Resolving Infection Susceptibility (RESIST), Hannover Medical School, Hannover, Germany
| | - Berislav Bošnjak
- Institute of Immunology, Hannover Medical School, Hannover, Germany..
| | | | - Theresa Graalmann
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany; Clinic of Immunology and Rheumatology, Hannover Medical School, Hannover, Germany..
| | - Ulrich Kalinke
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany; Cluster of Excellence - Resolving Infection Susceptibility (RESIST), Hannover Medical School, Hannover, Germany..
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5
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Hozsa C, Breunig M, Göpferich A. Monitoring the degradation of reduction-sensitive gene carriers with fluorescence spectroscopy and flow cytometry. Methods Mol Biol 2013; 991:171-184. [PMID: 23546669 DOI: 10.1007/978-1-62703-336-7_17] [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: 06/02/2023]
Abstract
Polycations like poly(ethylene imine) (PEI) or poly(L-lysine) (pLL) form nanometer-sized complexes with nucleic acids (polyplexes) which can be used for gene delivery. It is known that the properties of these -carriers can be greatly improved by introducing disulfide bridges on the polymers, thus making them reduction sensitive. However, little is known about how such modified carriers behave intracellularly. Here, we describe a method that uses the reduction-sensitive fluorescent dye BODIPY FL L-cystine to label PEI and pLL. Our probe is activated under reductive conditions leading to strongly increased fluorescence intensity. Subsequently, we show how the intracellular route of polyplexes made from these labeled polymers can be monitored by flow cytometry.
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Affiliation(s)
- Constantin Hozsa
- Lehrstuhl für Pharmazeutische Technologie, Universität Regensburg, Regensburg, Germany
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6
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Spoerner M, Hozsa C, Poetzl JA, Reiss K, Ganser P, Geyer M, Kalbitzer HR. Conformational states of human rat sarcoma (Ras) protein complexed with its natural ligand GTP and their role for effector interaction and GTP hydrolysis. J Biol Chem 2010; 285:39768-78. [PMID: 20937837 DOI: 10.1074/jbc.m110.145235] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The guanine nucleotide-binding protein Ras exists in solution in two different conformational states when complexed with different GTP analogs such as GppNHp or GppCH(2)p. State 1 has only a very low affinity to effectors and seems to be recognized by guanine nucleotide exchange factors, whereas state 2 represents the high affinity effector binding state. In this work we investigate Ras in complex with the physiological nucleoside triphosphate GTP. By polarization transfer (31)P NMR experiments and effector binding studies we show that Ras(wt)·Mg(2+)·GTP also exists in a dynamical equilibrium between the weakly populated conformational state 1 and the dominant state 2. At 278 K the equilibrium constant between state 1 and state 2 of C-terminal truncated wild-type Ras(1-166) K(12) is 11.3. K(12) of full-length Ras is >20, suggesting that the C terminus may also have a regulatory effect on the conformational equilibrium. The exchange rate (k(ex)) for Ras(wt)·Mg(2+)·GTP is 7 s(-1) and thus 18-fold lower compared with that found for the Ras·GppNHp complex. The intrinsic GTPase activity substantially increases after effector binding for the switch I mutants Ras(Y32F), (Y32R), (Y32W), (Y32C/C118S), (T35S), and the switch II mutant Ras(G60A) by stabilizing state 2, with the largest effect on Ras(Y32R) with a 13-fold increase compared with wild-type. In contrast, no acceleration was observed in Ras(T35A). Thus Ras in conformational state 2 has a higher affinity to effectors as well as a higher GTPase activity. These observations can be used to explain why many mutants have a low GTPase activity but are not oncogenic.
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Affiliation(s)
- Michael Spoerner
- Universität Regensburg, Institut für Biophysik und Physikalische Biochemie, Universitätsstrasse 31, 93053 Regensburg, Germany
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7
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Kalbitzer HR, Spoerner M, Ganser P, Hozsa C, Kremer W. Fundamental link between folding states and functional states of proteins. J Am Chem Soc 2010; 131:16714-9. [PMID: 19856908 DOI: 10.1021/ja904314q] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Folding and function of proteins are two aspects of proteins which are usually considered as basically unrelated phenomena that are optimized by evolution independently. From the funnel model of folding/unfolding and the associated energy landscape, we infer the paradigm that the minimum number of folding intermediates is determined by the number of all functional states of a protein ("essential" folding intermediates). Here, we demonstrate the supposed fundamental link using the Ras protein complexed with the GTP analogue GppNHp that occurs in two structural states coexisting in solution. State 2 was shown earlier to represent the effector interacting state, and the function of state 1 was hitherto unknown. By (31)P NMR spectroscopy, we demonstrate that state 1 represents the conformation interacting with guanine nucleotide exchange factors (GEFs). Denaturation experiments of the protein with a chaotropic reagent show that both functional states coexist during folding and unfolding. Application of high pressure represents another perturbation of the energy landscape, leading to an increased population of the state 1 as observed by NMR spectroscopy. The specific volume difference between the two states DeltaV(12) is 17.2 +/- 0.5 mL mol(-1), indicating that state 1 represents a more open conformation of the protein. The free energies of stabilization for state 1 and state 2 at 278 K can be determined as 8.3 and 9.8 kJ mol(-1), respectively.
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Affiliation(s)
- Hans Robert Kalbitzer
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, D-93040 Regensburg, Germany.
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Abstract
Nucleic acids are not only expected to assume a pivotal position as "drugs" in the treatment of genetic and acquired diseases, but could also act as molecular cues to control the microenvironment during tissue regeneration. Despite this promise, the efficient delivery of nucleic acids to their side of action is still the major hurdle. One among many prerequisites for a successful carrier system for nucleic acids is high stability in the extracellular environment, accompanied by an efficient release of the cargo in the intracellular compartment. A promising strategy to create such an interactive delivery system is to exploit the redox gradient between the extra- and intracellular compartments. In this review, emphasis is placed on the biological rationale for the synthesis of redox sensitive, disulfide-based carrier systems, as well as the extra- and intracellular processing of macromolecules containing disulfide bonds. Moreover, the basic synthetic approaches for introducing disulfide bonds into carrier molecules, together with examples that demonstrate the benefit of disulfides at the individual stages of nucleic acid delivery, will be presented.
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