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Elder JJH, Papadopoulos R, Hayne CK, Stanley RE. The making and breaking of tRNAs by ribonucleases. Trends Genet 2024:S0168-9525(24)00069-6. [PMID: 38641471 DOI: 10.1016/j.tig.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/21/2024] [Accepted: 03/21/2024] [Indexed: 04/21/2024]
Abstract
Ribonucleases (RNases) play important roles in supporting canonical and non-canonical roles of tRNAs by catalyzing the cleavage of the tRNA phosphodiester backbone. Here, we highlight how recent advances in cryo-electron microscopy (cryo-EM), protein structure prediction, reconstitution experiments, tRNA sequencing, and other studies have revealed new insight into the nucleases that process tRNA. This represents a very diverse group of nucleases that utilize distinct mechanisms to recognize and cleave tRNA during different stages of a tRNA's life cycle including biogenesis, fragmentation, surveillance, and decay. In this review, we provide a synthesis of the structure, mechanism, regulation, and modes of tRNA recognition by tRNA nucleases, along with open questions for future investigation.
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Affiliation(s)
- Jessica J H Elder
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Ry Papadopoulos
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA; Department of Chemistry, University of Chicago, Chicago, IL, USA
| | - Cassandra K Hayne
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA.
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA.
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2
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Panda A, Halder K, Debnath D, De S, Dasgupta S. Thermodynamics of the Association of Aminoglycoside Antibiotics with Human Angiogenin. Protein Pept Lett 2023; 30:92-101. [PMID: 36281865 DOI: 10.2174/0929866530666221021111823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/12/2022] [Accepted: 04/13/2022] [Indexed: 12/28/2022]
Abstract
BACKGROUND The body needs to maintain a firm balance between the inducers and inhibitors of angiogenesis, the process of proliferation of blood vessels from pre-existing ones. Human angiogenin (hAng), being a potent inducer of angiogenesis, is a cause of tumor cell proliferation, therefore its inhibition becomes a vital area of research. Aminoglycosides are linked ring systems consisting of amino sugars and an aminocyclitol ring and are in use in clinical practices for a long time. These compounds have found clinical uses as antibacterial agents that inhibit bacterial protein synthesis. OBJECTIVE Gentamycin C1, Kanamycin A, Neomycin B, Paromomycin I, and Streptomycin A are commonly used aminoglycoside antibiotics that have been used for the present study. Among these, Neomycin has reported inhibitory activity against angiogenin-induced angiogenesis on the chicken chorioallantoic membrane. This study focuses on the thermodynamic parameters involved in the interactions of these antibiotics with hAng. METHODS Agarose gel-based assay, Fluorescence quenching studies and Docking studies. RESULTS Anti-ribonucleolytic effect of the antibiotics was observed qualitatively using an agarose gelbased assay, which shows that Neomycin exhibits the most efficient inhibition of hAng. Fluorescence quenching studies at different temperatures, using Stern-Volmer and van't Hoff equations provide information about the thermodynamics of binding, which furthermore highlights the higher binding constant of Neomycin. Docking studies showed that the antibiotics preferably interact with the nuclear translocation site, except Streptomycin, which shows affinity towards the ribonucleolytic site of the protein with very less affinity value. CONCLUSION The study has shown the highly spontaneous formation of Neomycin-hAng complex, giving an exothermic reaction with increase in the degree of freedom of the protein-ligand complex.
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Affiliation(s)
- Atashi Panda
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Krishna Halder
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Debkumar Debnath
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Soumya De
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Swagata Dasgupta
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
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3
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Ahmad F, Lakshmi PTV, Arunachalam A. An in silico comparative study of curcumin and 2-deoxyuridine nucleoside derivatives: Reveals the role of angiogenin in ER stress-induced apoptosis signaling. Chem Biol Drug Des 2022; 101:1048-1081. [PMID: 36412086 DOI: 10.1111/cbdd.14184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 09/06/2022] [Accepted: 11/16/2022] [Indexed: 11/23/2022]
Abstract
Angiogenin (ANG) protein plays a crucial role in angiogenesis, neovascularization, and cancer metastasis in NSCLC (non-small cell lung cancer) via non-coding tiRNA. It protects the cell under ER (endoplasmic reticulum) stress-induced apoptosis through the translational reprogramming process. Although B82 (Curcumin derivatives) induces ER stress-induced apoptosis, its mechanism of action was not studied. Therefore, it was hypothesized that the ribonucleolytic activity of ANG may be regulated by B82, resulting in modulated ER stress signaling for apoptosis. Hence, we designed and proposed a synthesis scheme for RNA-based anti-angiogenic derivatives of 2-deoxyuridine nucleoside forming peptide bond with amino acids like serine (Ser-3) and para-hydroxy-phenyl glycine (Normtyr-1) and compared B82 with them to know the binding affinity with ANG, anti-angiogenic potential, and its probable mechanism of anti-RNase activity through MD simulation study. Therefore, using Gromos96 43a1 and 43a2 force fields, MD simulation was performed to investigate binding affinity, ligand-induced molecular surface area change, conformational change, and dynamics of catalytic site residues to predict ligand binding to ANG in this study. The obtained binding free energy (∆Gbind ) result showed the total average ∆Gbind as -113.480 ± 1.682 (Normtyr-1) > -53.038 ± 33.069 (B82) > -27.909 ± 16.438 (Ser-3) kJ/mole specify role of B82 in regulating ER stress signaling induced apoptosis through ANG ribonucleolytic activity inhibition, suitability of 43a2 force fields and methodology in ligand screening. It shows the crucial role of Leu115 and His13 residue involvement in total ∆Gbind contribution. Hence, based on the MD result, novel conformation of catalytic residues, and ∆Gbind , a promising combination candidate could be proposed for metastatic NSCLC therapy.
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Affiliation(s)
- Faizan Ahmad
- Department of Bioinformatics, Pondicherry University, Pondicherry, India
| | | | - Annamalai Arunachalam
- PG and Research Department of Botany Arignar Anna Government Arts College Villupuram Tamil Nadu India
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Sievers K, Ficner R. Structure of angiogenin dimer bound to double-stranded RNA. Acta Crystallogr F Struct Biol Commun 2022; 78:330-337. [PMID: 36048083 PMCID: PMC9435672 DOI: 10.1107/s2053230x22008317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 08/20/2022] [Indexed: 11/23/2022] Open
Abstract
Angiogenin is a pathologically relevant but little understood ribonuclease, the interactions of which with RNA are structurally unknown. Here, the first crystal structure of human angiogenin bound to RNA is presented. Angiogenin is an unusual member of the RNase A family and is of great interest in multiple pathological contexts. Although it has been assigned various regulatory roles, its core catalytic function is that of an RNA endonuclease. However, its catalytic efficiency is comparatively low and this has been linked to a unique C-terminal helix which partially blocks its RNA-binding site. Assuming that binding to its RNA substrate could trigger a conformational rearrangement, much speculation has arisen on the topic of the interaction of angiogenin with RNA. To date, no structural data on angiogenin–RNA interactions have been available. Here, the structure of angiogenin bound to a double-stranded RNA duplex is reported. The RNA does not reach the active site of angiogenin and no structural arrangement of the C-terminal domain is observed. However, angiogenin forms a previously unobserved crystallographic dimer that makes several backbone interactions with the major and minor grooves of the RNA double helix.
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Garnett ER, Raines RT. Emerging biological functions of ribonuclease 1 and angiogenin. Crit Rev Biochem Mol Biol 2021; 57:244-260. [PMID: 34886717 DOI: 10.1080/10409238.2021.2004577] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Pancreatic-type ribonucleases (ptRNases) are a large family of vertebrate-specific secretory endoribonucleases. These enzymes catalyze the degradation of many RNA substrates and thereby mediate a variety of biological functions. Though the homology of ptRNases has informed biochemical characterization and evolutionary analyses, the understanding of their biological roles is incomplete. Here, we review the functions of two ptRNases: RNase 1 and angiogenin. RNase 1, which is an abundant ptRNase with high catalytic activity, has newly discovered roles in inflammation and blood coagulation. Angiogenin, which promotes neovascularization, is now known to play roles in the progression of cancer and amyotrophic lateral sclerosis, as well as in the cellular stress response. Ongoing work is illuminating the biology of these and other ptRNases.
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Affiliation(s)
- Emily R Garnett
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ronald T Raines
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
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Angiogenin and Copper Crossing in Wound Healing. Int J Mol Sci 2021; 22:ijms221910704. [PMID: 34639045 PMCID: PMC8509573 DOI: 10.3390/ijms221910704] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 09/29/2021] [Accepted: 10/01/2021] [Indexed: 02/06/2023] Open
Abstract
Angiogenesis plays a key role in the wound healing process, involving the migration, growth, and differentiation of endothelial cells. Angiogenesis is controlled by a strict balance of different factors, and among these, the angiogenin protein plays a relevant role. Angiogenin is a secreted protein member of the ribonuclease superfamily that is taken up by cells and translocated to the nucleus when the process of blood vessel formation has to be promoted. However, the chemical signaling that activates the protein, normally present in the plasma, and the transport pathways through which the protein enters the cell are still largely unclear. Copper is also an angiogenic factor that regulates angiogenin expression and participates in the activation of common signaling pathways. The interaction between angiogenin and copper could be a relevant mechanism in regulating the formation of new blood vessel pathways and paving the way to the development of new drugs for chronic non-healing wounds.
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Dimerization of Human Angiogenin and of Variants Involved in Neurodegenerative Diseases. Int J Mol Sci 2021; 22:ijms221810068. [PMID: 34576228 PMCID: PMC8468037 DOI: 10.3390/ijms221810068] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/14/2021] [Accepted: 09/15/2021] [Indexed: 11/25/2022] Open
Abstract
Human Angiogenin (hANG, or ANG, 14.1 kDa) promotes vessel formation and is also called RNase 5 because it is included in the pancreatic-type ribonuclease (pt-RNase) super-family. Although low, its ribonucleolytic activity is crucial for angiogenesis in tumor tissues but also in the physiological development of the Central Nervous System (CNS) neuronal progenitors. Nevertheless, some ANG variants are involved in both neurodegenerative Parkinson disease (PD) and Amyotrophic Lateral Sclerosis (ALS). Notably, some pt-RNases acquire new biological functions upon oligomerization. Considering neurodegenerative diseases correlation with massive protein aggregation, we analyzed the aggregation propensity of ANG and of three of its pathogenic variants, namely H13A, S28N, and R121C. We found no massive aggregation, but wt-ANG, as well as S28N and R121C variants, can form an enzymatically active dimer, which is called ANG-D. By contrast, the enzymatically inactive H13A-ANG does not dimerize. Corroborated by a specific cross-linking analysis and by the behavior of H13A-ANG that in turn lacks one of the two His active site residues necessary for pt-RNases to self-associate through the three-dimensional domain swapping (3D-DS), we demonstrate that ANG actually dimerizes through 3D-DS. Then, we deduce by size exclusion chromatography (SEC) and modeling that ANG-D forms through the swapping of ANG N-termini. In light of these novelties, we can expect future investigations to unveil other ANG determinants possibly related with the onset and/or development of neurodegenerative pathologies.
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Shigematsu M, Kawamura T, Morichika K, Izumi N, Kiuchi T, Honda S, Pliatsika V, Matsubara R, Rigoutsos I, Katsuma S, Tomari Y, Kirino Y. RNase κ promotes robust piRNA production by generating 2',3'-cyclic phosphate-containing precursors. Nat Commun 2021; 12:4498. [PMID: 34301931 PMCID: PMC8302750 DOI: 10.1038/s41467-021-24681-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 07/01/2021] [Indexed: 11/13/2022] Open
Abstract
In animal germlines, PIWI proteins and the associated PIWI-interacting RNAs (piRNAs) protect genome integrity by silencing transposons. Here we report the extensive sequence and quantitative correlations between 2',3'-cyclic phosphate-containing RNAs (cP-RNAs), identified using cP-RNA-seq, and piRNAs in the Bombyx germ cell line and mouse testes. The cP-RNAs containing 5'-phosphate (P-cP-RNAs) identified by P-cP-RNA-seq harbor highly consistent 5'-end positions as the piRNAs and are loaded onto PIWI protein, suggesting their direct utilization as piRNA precursors. We identified Bombyx RNase Kappa (BmRNase κ) as a mitochondria-associated endoribonuclease which produces cP-RNAs during piRNA biogenesis. BmRNase κ-depletion elevated transposon levels and disrupted a piRNA-mediated sex determination in Bombyx embryos, indicating the crucial roles of BmRNase κ in piRNA biogenesis and embryonic development. Our results reveal a BmRNase κ-engaged piRNA biogenesis pathway, in which the generation of cP-RNAs promotes robust piRNA production.
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Affiliation(s)
- Megumi Shigematsu
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Takuya Kawamura
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Keisuke Morichika
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Natsuko Izumi
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-Ku, Tokyo, Japan
| | - Takashi Kiuchi
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-Ku, Tokyo, Japan
| | - Shozo Honda
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Venetia Pliatsika
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Ryuma Matsubara
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Isidore Rigoutsos
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-Ku, Tokyo, Japan
| | - Yukihide Tomari
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-Ku, Tokyo, Japan
| | - Yohei Kirino
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA.
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Sica F, Russo Krauss I, Troisi R, Bosso A, Culurciello R, Carluccio C, Trapani M, Merlino A, Mazzarella L, Pizzo E. The structural features of an ancient ribonuclease from Salmo salar reveal an intriguing case of auto-inhibition. Int J Biol Macromol 2021; 182:659-668. [PMID: 33848550 DOI: 10.1016/j.ijbiomac.2021.04.041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 04/07/2021] [Accepted: 04/07/2021] [Indexed: 10/21/2022]
Abstract
The superfamily of vertebrate ribonucleases, a large group of evolutionarily related proteins, continues to provide interesting structural and functional information. In particular, the crystal structure of SS-RNase-2 from Salmo salar (SS2), here presented, has revealed a novel auto-inhibition mechanism that enriches the number of inhibition strategies observed in some members of the family. Within an essentially unmodified RNase folding, the SS2 active site cleft is in part obstructed by the collapse of an extra pentapeptide inserted in the C-terminal region. This unexpected intrusion alters the organization of the catalytic triad by pushing one catalytic histidine off the pocket. Possible mechanisms to remove the active site obstruction have also been studied through the production of two mutants that provide useful information on the functionality of this intriguing version of the ribonuclease superfamily.
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Affiliation(s)
- Filomena Sica
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia, I-80126 Naples, Italy.
| | - Irene Russo Krauss
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia, I-80126 Naples, Italy; CSGI (Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase), Via della Lastruccia 3, I-50019 Sesto Fiorentino, FI, Italy
| | - Romualdo Troisi
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia, I-80126 Naples, Italy
| | - Andrea Bosso
- Department of Biology, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia, I-80126 Naples, Italy
| | - Rosanna Culurciello
- Department of Biology, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia, I-80126 Naples, Italy
| | - Carla Carluccio
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia, I-80126 Naples, Italy
| | - Mariateresa Trapani
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia, I-80126 Naples, Italy
| | - Antonello Merlino
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia, I-80126 Naples, Italy
| | - Lelio Mazzarella
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia, I-80126 Naples, Italy; Accademia di Scienze Fisiche e Matematiche della Società Nazionale di Scienze, Lettere ed Arti in Napoli, Naples, Italy
| | - Elio Pizzo
- Department of Biology, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia, I-80126 Naples, Italy
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Panda A, Karhadkar S, Acharya B, Banerjee A, De S, Dasgupta S. Enhancement of angiogenin inhibition by polyphenol-capped gold nanoparticles. Biopolymers 2021; 112:e23429. [PMID: 33851721 DOI: 10.1002/bip.23429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 02/27/2021] [Accepted: 03/22/2021] [Indexed: 11/10/2022]
Abstract
Angiogenin (Ang), is a ribonucleolytic protein that is associated with angiogenesis, the formation of blood vessels. The involvement of Ang in vascularisation makes it a potential target for the identification of compounds that have the potential to inhibit the process. The compounds may be assessed for their ability to inhibit the ribonucleolytic activity of the protein and subsequently blood vessel formation, a crucial requirement for tumor formation. We report an inhibition of the ribonucleolytic activity of Ang with the gallate containing green tea polyphenols, ECG and EGCG that exhibits an increased efficacy upon forming polyphenol-capped gold nanoparticles (ECG-AuNPs and EGCG-AuNPs). The extent of inhibition was confirmed using an agarose gel-based assay followed by fluorescence titration studies that indicated a hundred fold stronger binding of polyphenol-capped gold nanoparticles (GTP-AuNPs) compared to the bare polyphenols. Interestingly, we found a change in the mode of inhibition from a noncompetitive type to a competitive mode of inhibition in case of the GTP-AuNPs, which is in agreement with the 'n' values obtained from the fluorescence quenching studies. The effect on angiogenesis has also been assessed by the chorioallantoic membrane (CAM) assay. We find an increase in the inhibition potency of GTP-AuNPs that could find applications in the development of anti-angiogenic compounds.
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Affiliation(s)
- Atashi Panda
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Siddhant Karhadkar
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Bidisha Acharya
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Anwesha Banerjee
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Soumya De
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Swagata Dasgupta
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India
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NMR Characterization of Angiogenin Variants and tRNA Ala Products Impacting Aberrant Protein Oligomerization. Int J Mol Sci 2021; 22:ijms22031439. [PMID: 33535464 PMCID: PMC7867098 DOI: 10.3390/ijms22031439] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 01/25/2021] [Accepted: 01/27/2021] [Indexed: 11/25/2022] Open
Abstract
Protein oligomerization is key to countless physiological processes, but also to abnormal amyloid conformations implicated in over 25 mortal human diseases. Human Angiogenin (h-ANG), a ribonuclease A family member, produces RNA fragments that regulate ribosome formation, the creation of new blood vessels and stress granule function. Too little h-ANG activity leads to abnormal protein oligomerization, resulting in Amyotrophic Lateral Sclerosis (ALS) or Parkinson’s disease. While a score of disease linked h-ANG mutants has been studied by X-ray diffraction, some elude crystallization. There is also a debate regarding the structure that RNA fragments adopt after cleavage by h-ANG. Here, to better understand the beginning of the process that leads to aberrant protein oligomerization, the solution secondary structure and residue-level dynamics of WT h-ANG and two mutants i.e., H13A and R121C, are characterized by multidimensional heteronuclear NMR spectroscopy under near-physiological conditions. All three variants are found to adopt well folded and highly rigid structures in the solution, although the elements of secondary structure are somewhat shorter than those observed in crystallography studies. R121C alters the environment of nearby residues only. By contrast, the mutation H13A affects local residues as well as nearby active site residues K40 and H114. The conformation characterization by CD and 1D 1H NMR spectroscopies of tRNAAla before and after h-ANG cleavage reveals a retention of the duplex structure and little or no G-quadruplex formation.
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Bedenbender K, Schmeck BT. Endothelial Ribonuclease 1 in Cardiovascular and Systemic Inflammation. Front Cell Dev Biol 2020; 8:576491. [PMID: 33015070 PMCID: PMC7500176 DOI: 10.3389/fcell.2020.576491] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/14/2020] [Indexed: 12/12/2022] Open
Abstract
The vascular endothelial cell layer forms the inner lining of all blood vessels to maintain proper functioning of the vascular system. However, dysfunction of the endothelium depicts a major issue in context of vascular pathologies, such as atherosclerosis or thrombosis that cause several million deaths per year worldwide. In recent years, the endothelial extracellular endonuclease Ribonuclease 1 (RNase1) was described as a key player in regulation of vascular homeostasis by protecting endothelial cells from detrimental effects of the damage-associated molecular pattern extracellular RNA upon acute inflammation. Despite this protective function, massive dysregulation of RNase1 was observed during prolonged endothelial cell inflammation resulting in progression of several vascular diseases. For the first time, this review article outlines the current knowledge on endothelial RNase1 and its role in function and dysfunction of the endothelium, thereby focusing on the intensive research from recent years: Uncovering the underlying mechanisms of RNase1 function and regulation in response to acute as well as long-term inflammation, the role of RNase1 in context of vascular, inflammatory and infectious diseases and the potential to develop novel therapeutic options to treat these pathologies against the background of RNase1 function in endothelial cells.
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Affiliation(s)
- Katrin Bedenbender
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Marburg, Germany
| | - Bernd T. Schmeck
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Marburg, Germany
- Department of Pulmonary and Critical Care Medicine, Department of Medicine, University Medical Center Giessen and Marburg, Philipps-University Marburg, Marburg, Germany
- Member of the German Center for Lung Research, Member of the German Center for Infectious Disease Research, Marburg, Germany
- Center for Synthetic Microbiology, Philipps-University Marburg, Marburg, Germany
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Su Z, Kuscu C, Malik A, Shibata E, Dutta A. Angiogenin generates specific stress-induced tRNA halves and is not involved in tRF-3-mediated gene silencing. J Biol Chem 2019; 294:16930-16941. [PMID: 31582561 DOI: 10.1074/jbc.ra119.009272] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 09/27/2019] [Indexed: 01/13/2023] Open
Abstract
tRNA fragments (tRFs) and tRNA halves have been implicated in various cellular processes, including gene silencing, translation, stress granule assembly, cell differentiation, retrotransposon activity, symbiosis, apoptosis, and more. Overexpressed angiogenin (ANG) cleaves tRNA anticodons and produces tRNA halves similar to those produced in response to stress. However, it is not clear whether endogenous ANG is essential for producing the stress-induced tRNA halves. It is also not clear whether smaller tRFs are generated from the tRNA halves. Here, using global short RNA-Seq approach, we found that ANG overexpression selectively cleaves a subset of tRNAs, including tRNAGlu, tRNAGly, tRNALys, tRNAVal, tRNAHis, tRNAAsp, and tRNASeC to produce tRNA halves and tRF-5s that are 26-30 bases long. Surprisingly, ANG knockout revealed that the majority of stress-induced tRNA halves, except for the 5' half from tRNAHisGTG and the 3' half from tRNAAspGTC, are ANG independent, suggesting there are other RNases that produce tRNA halves. We also found that the 17-25 bases-long tRF-3s and tRF-5s that could enter into Argonaute complexes are not induced by ANG overexpression, suggesting that they are generated independently from tRNA halves. Consistent with this, ANG knockout did not decrease tRF-3 levels or gene-silencing activity. We conclude that ANG cleaves specific tRNAs and is not the only RNase that creates tRNA halves and that the shorter tRFs are not generated from the tRNA halves or from independent tRNA cleavage by ANG.
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Affiliation(s)
- Zhangli Su
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22901
| | - Canan Kuscu
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22901
| | - Asrar Malik
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22901
| | - Etsuko Shibata
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22901
| | - Anindya Dutta
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22901
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Ferguson R, Holloway DE, Chandrasekhar A, Acharya KR, Subramanian V. The catalytic activity and secretion of zebrafish RNases are essential for their in vivo function in motor neurons and vasculature. Sci Rep 2019; 9:1107. [PMID: 30710110 PMCID: PMC6358602 DOI: 10.1038/s41598-018-37140-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 11/29/2018] [Indexed: 12/14/2022] Open
Abstract
Angiogenin (hANG), a member of the Ribonuclease A superfamily has angiogenic, neurotrophic and neuroprotective activities. Mutations in hANG have been found in patients with Amyotrophic lateral sclerosis (ALS). The zebrafish (Danio rerio) rnasel-1, 2 and 3 are orthologues of hANG and of these only Rnasel-1 and Rnasel-2 have been shown to be angiogenic. Herein we show that NCI-65828, a potent and specific small molecule inhibitor of hANG inhibits Rnasel-1 to a similar extent. Treatment of early zebrafish embryos with NCI-65828, or with terrein, a fungal metabolite which prevents the secretion of hANG, resulted in spinal neuron aberrations as well defects in trunk vasculature. Our detailed expression analysis and inhibitor studies suggest that Rnasel-1 plays important roles in neuronal migration and pathfinding as well as in angiogenesis in zebrafish. Our studies suggest the usefulness of the zebrafish as a model to dissect the molecular consequences of the ANG ALS variants.
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Affiliation(s)
- Ross Ferguson
- Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, UK
| | - Daniel E Holloway
- Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, UK
| | - Anand Chandrasekhar
- Division of Biological Sciences and Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211-7310, USA
| | - K Ravi Acharya
- Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, UK
| | - Vasanta Subramanian
- Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, UK.
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15
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Targeted human cytolytic fusion proteins at the cutting edge: harnessing the apoptosis-inducing properties of human enzymes for the selective elimination of tumor cells. Oncotarget 2019; 10:897-915. [PMID: 30783518 PMCID: PMC6368230 DOI: 10.18632/oncotarget.26618] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 01/10/2019] [Indexed: 01/01/2023] Open
Abstract
Patient-specific targeted therapy represents the holy grail of anti-cancer therapeutics, allowing potent tumor depletion without detrimental off-target toxicities. Disease-specific monoclonal antibodies have been employed to bind to oncogenic cell-surface receptors, representing the earliest form of immunotherapy. Targeted drug delivery was first achieved by means of antibody-drug conjugates, which exploit the differential expression of tumor-associated antigens as a guiding mechanism for the specific delivery of chemically-conjugated chemotherapeutic agents to diseased target cells. Biotechnological advances have expanded the repertoire of immunology-based tumor-targeting strategies, also paving the way for the next intuitive step in targeted drug delivery: the construction of recombinant protein drugs consisting of an antibody-based targeting domain genetically fused with a cytotoxic peptide, known as an immunotoxin. However, the most potent protein toxins have typically been derived from bacterial or plant virulence factors and commonly feature both off-target toxicity and immunogenicity in human patients. Further refinement of immunotoxin technology thus led to the replacement of monoclonal antibodies with humanized antibody derivatives, including the substitution of non-human toxic peptides with human cytolytic proteins. Preclinically tested human cytolytic fusion proteins (hCFPs) have proven promising as non-immunogenic combinatory anti-cancer agents, however they still require further enhancement to achieve convincing candidacy as a single-mode therapeutic. To date, a portfolio of highly potent human toxins has been established; ranging from microtubule-associated protein tau (MAP tau), RNases, granzyme B (GrB) and death-associated protein kinase (DAPk). In this review, we discuss the most recent findings on the use of these apoptosis-inducing hCFPs for the treatment of various cancers.
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16
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Shigematsu M, Kawamura T, Kirino Y. Generation of 2',3'-Cyclic Phosphate-Containing RNAs as a Hidden Layer of the Transcriptome. Front Genet 2018; 9:562. [PMID: 30538719 PMCID: PMC6277466 DOI: 10.3389/fgene.2018.00562] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 11/06/2018] [Indexed: 01/03/2023] Open
Abstract
Cellular RNA molecules contain phosphate or hydroxyl ends. A 2′,3′-cyclic phosphate (cP) is one of the 3′-terminal forms of RNAs mainly generated from RNA cleavage by ribonucleases. Although transcriptome profiling using RNA-seq has become a ubiquitous tool in biological and medical research, cP-containing RNAs (cP-RNAs) form a hidden transcriptome layer, which is infrequently recognized and characterized, because standard RNA-seq is unable to capture them. Despite cP-RNAs’ invisibility in RNA-seq data, increasing evidence indicates that they are not accumulated simply as non-functional degradation products; rather, they have physiological roles in various biological processes, designating them as noteworthy functional molecules. This review summarizes our current knowledge of cP-RNA biogenesis pathways and their catalytic enzymatic activities, discusses how the cP-RNA generation affects biological processes, and explores future directions to further investigate cP-RNA biology.
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Affiliation(s)
- Megumi Shigematsu
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States
| | - Takuya Kawamura
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States
| | - Yohei Kirino
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States
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17
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Lyons SM, Fay MM, Ivanov P. The role of RNA modifications in the regulation of tRNA cleavage. FEBS Lett 2018; 592:2828-2844. [PMID: 30058219 DOI: 10.1002/1873-3468.13205] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 06/28/2018] [Accepted: 07/18/2018] [Indexed: 12/21/2022]
Abstract
Transfer RNA (tRNA) have been harbingers of many paradigms in RNA biology. They are among the first recognized noncoding RNA (ncRNA) playing fundamental roles in RNA metabolism. Although mainly recognized for their role in decoding mRNA and delivering amino acids to the growing polypeptide chain, tRNA also serve as an abundant source of small ncRNA named tRNA fragments. The functional significance of these fragments is only beginning to be uncovered. Early on, tRNA were recognized as heavily post-transcriptionally modified, which aids in proper folding and modulates the tRNA:mRNA anticodon-codon interactions. Emerging data suggest that these modifications play critical roles in the generation and activity of tRNA fragments. Modifications can both protect tRNA from cleavage or promote their cleavage. Modifications to individual fragments may be required for their activity. Recent work has shown that some modifications are critical for stem cell development and that failure to deposit certain modifications has profound effects on disease. This review will discuss how tRNA modifications regulate the generation and activity of tRNA fragments.
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Affiliation(s)
- Shawn M Lyons
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Marta M Fay
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Pavel Ivanov
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA.,The Broad Institute of Harvard and M.I.T., Cambridge, MA, USA
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18
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Jordaan S, Akinrinmade OA, Nachreiner T, Cremer C, Naran K, Chetty S, Barth S. Updates in the Development of ImmunoRNases for the Selective Killing of Tumor Cells. Biomedicines 2018; 6:biomedicines6010028. [PMID: 29510557 PMCID: PMC5874685 DOI: 10.3390/biomedicines6010028] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 03/02/2018] [Accepted: 03/03/2018] [Indexed: 12/14/2022] Open
Abstract
Targeted cancer therapy includes, amongst others, antibody-based delivery of toxic payloads to selectively eliminate tumor cells. This payload can be either a synthetic small molecule drug composing an antibody-drug conjugate (ADC) or a cytotoxic protein composing an immunotoxin (IT). Non-human cytotoxic proteins, while potent, have limited clinical efficacy due to their immunogenicity and potential off-target toxicity. Humanization of the cytotoxic payload is essential and requires harnessing of potent apoptosis-inducing human proteins with conditional activity, which rely on targeted delivery to contact their substrate. Ribonucleases are attractive candidates, due to their ability to induce apoptosis by abrogating protein biosynthesis via tRNA degradation. In fact, several RNases of the pancreatic RNase A superfamily have shown potential as anti-cancer agents. Coupling of a human RNase to a humanized antibody or antibody derivative putatively eliminates the immunogenicity of an IT (now known as a human cytolytic fusion protein, hCFP). However, RNases are tightly regulated in vivo by endogenous inhibitors, controlling the ribonucleolytic balance subject to the cell’s metabolic requirements. Endogenous inhibition limits the efficacy with which RNase-based hCFPs induce apoptosis. However, abrogating the natural interaction with the natural inhibitors by mutation has been shown to significantly enhance RNase activity, paving the way toward achieving cytolytic potency comparable to that of bacterial immunotoxins. Here, we review the immunoRNases that have undergone preclinical studies as anti-cancer therapeutic agents.
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Affiliation(s)
- Sandra Jordaan
- Medical Biotechnology and Immunotherapy Group, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7700, South Africa.
| | - Olusiji A Akinrinmade
- South African Research Chair in Cancer Biotechnology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town 7700, South Africa.
| | - Thomas Nachreiner
- Department of Experimental Medicine and Immunotherapy, Institute for Applied Medical Engineering, University Hospital RWTH Aachen, 52056 Aachen, Germany.
| | - Christian Cremer
- Department of Experimental Medicine and Immunotherapy, Institute for Applied Medical Engineering, University Hospital RWTH Aachen, 52056 Aachen, Germany.
| | - Krupa Naran
- Medical Biotechnology and Immunotherapy Group, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7700, South Africa.
- South African Research Chair in Cancer Biotechnology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town 7700, South Africa.
| | - Shivan Chetty
- Medical Biotechnology and Immunotherapy Group, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7700, South Africa.
- South African Research Chair in Cancer Biotechnology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town 7700, South Africa.
| | - Stefan Barth
- Medical Biotechnology and Immunotherapy Group, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7700, South Africa.
- South African Research Chair in Cancer Biotechnology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town 7700, South Africa.
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19
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Lyons SM, Fay MM, Akiyama Y, Anderson PJ, Ivanov P. RNA biology of angiogenin: Current state and perspectives. RNA Biol 2017; 14:171-178. [PMID: 28010172 DOI: 10.1080/15476286.2016.1272746] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Angiogenin (ANG) is a secreted ribonuclease best known for its ability to promote formation of blood vessels. Extensive research over many years has elucidated its structure and biophysical properties, although our knowledge of molecular mechanisms underlying ANG-associated biologic processes remains limited. Intriguingly, many of processes require the ribonuclease activity of ANG, thus highlighting the importance of identifying and characterizing RNA targets and intermediates of ANG-mediated endonucleolytic cleavage. While ANG demonstrates ribonuclease activity toward many RNA substrates in vitro, specific target of ANG, namely mature tRNA, was only recently identified in vivo. ANG-mediated tRNA cleavage is an unorthodox manner of generating non-coding RNAs with diverse biologic activities. In addition, the ribonuclease activity of ANG has been reported to be crucial for rRNA transcription. Here we critically discuss various aspects of ANG biology related to its RNase activity and discuss areas in need of further investigation.
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Affiliation(s)
- Shawn M Lyons
- a Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital , Boston , MA , USA.,b Department of Medicine , Harvard Medical School , Boston , MA , USA
| | - Marta M Fay
- a Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital , Boston , MA , USA.,b Department of Medicine , Harvard Medical School , Boston , MA , USA
| | - Yasutoshi Akiyama
- a Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital , Boston , MA , USA.,b Department of Medicine , Harvard Medical School , Boston , MA , USA
| | - Paul J Anderson
- a Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital , Boston , MA , USA.,b Department of Medicine , Harvard Medical School , Boston , MA , USA
| | - Pavel Ivanov
- a Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital , Boston , MA , USA.,b Department of Medicine , Harvard Medical School , Boston , MA , USA.,c The BROAD Institute of Harvard and MIT , Cambridge , MA , USA
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20
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Hoang TT, Smith TP, Raines RT. A Boronic Acid Conjugate of Angiogenin that Shows ROS-Responsive Neuroprotective Activity. Angew Chem Int Ed Engl 2017; 56:2619-2622. [PMID: 28120377 PMCID: PMC5418131 DOI: 10.1002/anie.201611446] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 12/23/2016] [Indexed: 12/27/2022]
Abstract
Angiogenin (ANG) is a human ribonuclease that is compromised in patients with amyotrophic lateral sclerosis (ALS). ANG also promotes neovascularization, and can induce hemorrhage and encourage tumor growth. The causal neurodegeneration of ALS is associated with reactive oxygen species, which are also known to elicit the oxidative cleavage of carbon-boron bonds. We have developed a synthetic boronic acid mask that restrains the ribonucleolytic activity of ANG. The masked ANG does not stimulate endothelial cell proliferation but protects astrocytes from oxidative stress. By differentiating between the two dichotomous biological activities of ANG, this strategy could provide a viable pharmacological approach for the treatment of ALS.
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Affiliation(s)
- Trish T Hoang
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI, 53706-1544, USA
| | - Thomas P Smith
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI, 53706-1322, USA
| | - Ronald T Raines
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI, 53706-1544, USA
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI, 53706-1322, USA
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21
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Bradshaw WJ, Rehman S, Pham TTK, Thiyagarajan N, Lee RL, Subramanian V, Acharya KR. Structural insights into human angiogenin variants implicated in Parkinson's disease and Amyotrophic Lateral Sclerosis. Sci Rep 2017; 7:41996. [PMID: 28176817 PMCID: PMC5296752 DOI: 10.1038/srep41996] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 01/04/2017] [Indexed: 12/11/2022] Open
Abstract
Mutations in Angiogenin (ANG), a member of the Ribonuclease A superfamily (also known as RNase 5) are known to be associated with Amyotrophic Lateral Sclerosis (ALS, motor neurone disease) (sporadic and familial) and Parkinson’s Disease (PD). In our previous studies we have shown that ANG is expressed in neurons during neuro-ectodermal differentiation, and that it has both neurotrophic and neuroprotective functions. In addition, in an extensive study on selective ANG-ALS variants we correlated the structural changes to the effects on neuronal survival and the ability to induce stress granules in neuronal cell lines. Furthermore, we have established that ANG-ALS variants which affect the structure of the catalytic site and either decrease or increase the RNase activity affect neuronal survival. Neuronal cell lines expressing the ANG-ALS variants also lack the ability to form stress granules. Here, we report a detailed experimental structural study on eleven new ANG-PD/ALS variants which will have implications in understanding the molecular basis underlying their role in PD and ALS.
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Affiliation(s)
- William J Bradshaw
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Saima Rehman
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Tram T K Pham
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Nethaji Thiyagarajan
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Rebecca L Lee
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Vasanta Subramanian
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - K Ravi Acharya
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
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22
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Hoang TT, Raines RT. Molecular basis for the autonomous promotion of cell proliferation by angiogenin. Nucleic Acids Res 2017; 45:818-831. [PMID: 27915233 PMCID: PMC5314776 DOI: 10.1093/nar/gkw1192] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 11/13/2016] [Accepted: 11/20/2016] [Indexed: 12/13/2022] Open
Abstract
Canonical growth factors act indirectly via receptor-mediated signal transduction pathways. Here, we report on an autonomous pathway in which a growth factor is internalized, has its localization regulated by phosphorylation, and ultimately uses intrinsic catalytic activity to effect epigenetic change. Angiogenin (ANG), a secreted vertebrate ribonuclease, is known to promote cell proliferation, leading to neovascularization as well as neuroprotection in mammals. Upon entering cells, ANG encounters the cytosolic ribonuclease inhibitor protein, which binds with femtomolar affinity. We find that protein kinase C and cyclin-dependent kinase phosphorylate ANG, enabling ANG to evade its inhibitor and enter the nucleus. After migrating to the nucleolus, ANG cleaves promoter-associated RNA, which prevents the recruitment of the nucleolar remodeling complex to the ribosomal DNA promoter. The ensuing derepression of rDNA transcription promotes cell proliferation. The biochemical basis for this unprecedented mechanism of signal transduction suggests new modalities for the treatment of cancers and neurological disorders.
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Affiliation(s)
- Trish T Hoang
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Ronald T Raines
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
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23
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Hoang TT, Smith TP, Raines RT. A Boronic Acid Conjugate of Angiogenin that Shows ROS-Responsive Neuroprotective Activity. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611446] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Trish T. Hoang
- Department of Biochemistry; University of Wisconsin-Madison; 433 Babcock Drive Madison WI 53706-1544 USA
| | - Thomas P. Smith
- Department of Chemistry; University of Wisconsin-Madison; 1101 University Avenue Madison WI 53706-1322 USA
| | - Ronald T. Raines
- Department of Biochemistry; University of Wisconsin-Madison; 433 Babcock Drive Madison WI 53706-1544 USA
- Department of Chemistry; University of Wisconsin-Madison; 1101 University Avenue Madison WI 53706-1322 USA
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24
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Chatzileontiadou DSM, Tsirkone VG, Dossi K, Kassouni AG, Liggri PGV, Kantsadi AL, Stravodimos GA, Balatsos NAA, Skamnaki VT, Leonidas DD. The ammonium sulfate inhibition of human angiogenin. FEBS Lett 2016; 590:3005-18. [PMID: 27483019 DOI: 10.1002/1873-3468.12335] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 07/17/2016] [Accepted: 07/22/2016] [Indexed: 11/09/2022]
Abstract
In this study, we investigate the inhibition of human angiogenin by ammonium sulfate. The inhibitory potency of ammonium sulfate for human angiogenin (IC50 = 123.5 ± 14.9 mm) is comparable to that previously reported for RNase A (119.0 ± 6.5 mm) and RNase 2 (95.7 ± 9.3 mm). However, analysis of two X-ray crystal structures of human angiogenin in complex with sulfate anions (in acidic and basic pH environments, respectively) indicates an entirely distinct mechanism of inhibition. While ammonium sulfate inhibits the ribonucleolytic activity of RNase A and RNase 2 by binding to the active site of these enzymes, sulfate anions bind only to peripheral substrate anion-binding subsites of human angiogenin, and not to the active site.
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Affiliation(s)
| | - Vicky G Tsirkone
- Institute of Biology, Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation, Athens, Greece
| | - Kyriaki Dossi
- Institute of Biology, Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation, Athens, Greece
| | - Aikaterini G Kassouni
- Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece
| | - Panagiota G V Liggri
- Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece
| | - Anastassia L Kantsadi
- Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece
| | - George A Stravodimos
- Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece
| | - Nikolaos A A Balatsos
- Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece
| | - Vassiliki T Skamnaki
- Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece
| | - Demetres D Leonidas
- Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece
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25
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Cong X, Cremer C, Nachreiner T, Barth S, Carloni P. Engineered human angiogenin mutations in the placental ribonuclease inhibitor complex for anticancer therapy: Insights from enhanced sampling simulations. Protein Sci 2016; 25:1451-60. [PMID: 27110669 PMCID: PMC4972201 DOI: 10.1002/pro.2941] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 04/20/2016] [Indexed: 01/29/2023]
Abstract
Targeted human cytolytic fusion proteins (hCFPs) represent a new generation of immunotoxins (ITs) for the specific targeting and elimination of malignant cell populations. Unlike conventional ITs, hCFPs comprise a human/humanized target cell-specific binding moiety (e.g., an antibody or a fragment thereof) fused to a human proapoptotic protein as the cytotoxic domain (effector domain). Therefore, hCFPs are humanized ITs expected to have low immunogenicity. This reduces side effects and allows long-term application. The human ribonuclease angiogenin (Ang) has been shown to be a promising effector domain candidate. However, the application of Ang-based hCFPs is largely hampered by the intracellular placental ribonuclease inhibitor (RNH1). It rapidly binds and inactivates Ang. Mutations altering Ang's affinity for RNH1 modulate the cytotoxicity of Ang-based hCFPs. Here we perform in total 2.7 µs replica-exchange molecular dynamics simulations to investigate some of these mutations-G85R/G86R (GGRRmut ), Q117G (QGmut ), and G85R/G86R/Q117G (GGRR/QGmut ). GGRRmut turns out to perturb greatly the overall Ang-RNH1 interactions, whereas QGmut optimizes them. Combining QGmut with GGRRmut compensates the effects of the latter. Our results explain the in vitro finding that, while Ang GGRRmut -based hCFPs resist RNH1 inhibition remarkably, Ang WT- and Ang QGmut -based ones are similarly sensitive to RNH1 inhibition, whereas Ang GGRR/QGmut -based ones are only slightly resistant. This work may help design novel Ang mutants with reduced affinity for RNH1 and improved cytotoxicity.
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Affiliation(s)
- Xiaojing Cong
- Computational Biophysics, German Research School for Simulation Sciences (Joint Venture of RWTH Aachen University and Forschungszentrum Jülich)Jülich52428Germany
- Computational Biomedicine Section, Institute for Advanced Simulations ‐ 5 (IAS‐5)Jülich52428GermanyForschungszentrum Jülich
- Computational Biomedicine Section, Institute for Neuroscience and Medicine ‐ 9 (INM‐9)Jülich52428GermanyForschungszentrum Jülich
| | - Christian Cremer
- Department of Experimental Medicine and Immunotherapy, Institute for Applied Medical EngineeringUniversity Hospital RWTH AachenAachen52074Germany
| | - Thomas Nachreiner
- Department of Experimental Medicine and Immunotherapy, Institute for Applied Medical EngineeringUniversity Hospital RWTH AachenAachen52074Germany
| | - Stefan Barth
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape TownCape Town7925South Africa
- South African Research Chair in Cancer Biotechnology, Department of Integrative Biomedical Sciences, Faculty of Health SciencesUniversity of Cape Town7925Cape TownSouth Africa
| | - Paolo Carloni
- Computational Biophysics, German Research School for Simulation Sciences (Joint Venture of RWTH Aachen University and Forschungszentrum Jülich)Jülich52428Germany
- Computational Biomedicine Section, Institute for Advanced Simulations ‐ 5 (IAS‐5)Jülich52428GermanyForschungszentrum Jülich
- Computational Biomedicine Section, Institute for Neuroscience and Medicine ‐ 9 (INM‐9)Jülich52428GermanyForschungszentrum Jülich
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26
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Cremer C, Braun H, Mladenov R, Schenke L, Cong X, Jost E, Brümmendorf TH, Fischer R, Carloni P, Barth S, Nachreiner T. Novel angiogenin mutants with increased cytotoxicity enhance the depletion of pro-inflammatory macrophages and leukemia cells ex vivo. Cancer Immunol Immunother 2015; 64:1575-86. [PMID: 26472728 PMCID: PMC11028715 DOI: 10.1007/s00262-015-1763-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 09/29/2015] [Indexed: 10/22/2022]
Abstract
Immunotoxins are fusion proteins that combine a targeting component such as an antibody fragment or ligand with a cytotoxic effector component that induces apoptosis in specific cell populations displaying the corresponding antigen or receptor. Human cytolytic fusion proteins (hCFPs) are less immunogenic than conventional immunotoxins because they contain human pro-apoptotic enzymes as effectors. However, one drawback of hCFPs is that target cells can protect themselves by expressing endogenous inhibitor proteins. Inhibitor-resistant enzyme mutants that maintain their cytotoxic activity are therefore promising effector domain candidates. We recently developed potent variants of the human ribonuclease angiogenin (Ang) that were either more active than the wild-type enzyme or less susceptible to inhibition because of their lower affinity for the ribonuclease inhibitor RNH1. However, combining the mutations was unsuccessful because although the enzyme retained its higher activity, its susceptibility to RNH1 reverted to wild-type levels. We therefore used molecular dynamic simulations to determine, at the atomic level, why the affinity for RNH1 reverted, and we developed strategies based on the introduction of further mutations to once again reduce the affinity of Ang for RNH1 while retaining its enhanced activity. We were able to generate a novel Ang variant with remarkable in vitro cytotoxicity against HL-60 cells and pro-inflammatory macrophages. We also demonstrated the pro-apoptotic potential of Ang-based hCFPs on cells freshly isolated from leukemia patients.
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Affiliation(s)
- Christian Cremer
- Department of Experimental Medicine and Immunotherapy, Institute for Applied Medical Engineering, University Hospital RWTH Aachen, Pauwelsstr. 20, 52074, Aachen, Germany
| | - Hanna Braun
- Department of Experimental Medicine and Immunotherapy, Institute for Applied Medical Engineering, University Hospital RWTH Aachen, Pauwelsstr. 20, 52074, Aachen, Germany
| | - Radoslav Mladenov
- Department of Pharmaceutical Product Development, Fraunhofer Institute for Molecular Biology and Applied Ecology, Forckenbeckstr. 6, 52074, Aachen, Germany
| | - Lea Schenke
- Department of Experimental Medicine and Immunotherapy, Institute for Applied Medical Engineering, University Hospital RWTH Aachen, Pauwelsstr. 20, 52074, Aachen, Germany
| | - Xiaojing Cong
- Department of Computational Biophysics, German Research School for Simulation Sciences (Joint Venture of RWTH Aachen University and Forschungszentrum Jülich), 52428, Jülich, Germany
- Institute for Advanced Simulations IAS-5, Computational Biomedicine, Forschungszentrum, Jülich, Germany
| | - Edgar Jost
- Department of Hematology and Oncology (Internal Medicine IV), University Hospital RWTH Aachen, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Tim H Brümmendorf
- Department of Hematology and Oncology (Internal Medicine IV), University Hospital RWTH Aachen, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Rainer Fischer
- Department of Pharmaceutical Product Development, Fraunhofer Institute for Molecular Biology and Applied Ecology, Forckenbeckstr. 6, 52074, Aachen, Germany
- Institute for Molecular Biotechnology, RWTH Aachen University, Worringer Weg 1, 52074, Aachen, Germany
| | - Paolo Carloni
- Department of Computational Biophysics, German Research School for Simulation Sciences (Joint Venture of RWTH Aachen University and Forschungszentrum Jülich), 52428, Jülich, Germany
- Institute for Advanced Simulations IAS-5, Computational Biomedicine, Forschungszentrum, Jülich, Germany
| | - Stefan Barth
- Department of Experimental Medicine and Immunotherapy, Institute for Applied Medical Engineering, University Hospital RWTH Aachen, Pauwelsstr. 20, 52074, Aachen, Germany
- South African Research Chair in Cancer Biotechnology, Institute of Infectious Disease and Molecular Medicine (IDM), Anzio Road, Observatory, Cape Town, 7925, South Africa
- Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory, Cape Town, 7925, South Africa
| | - Thomas Nachreiner
- Department of Experimental Medicine and Immunotherapy, Institute for Applied Medical Engineering, University Hospital RWTH Aachen, Pauwelsstr. 20, 52074, Aachen, Germany.
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Gagné D, Narayanan C, Doucet N. Network of long-range concerted chemical shift displacements upon ligand binding to human angiogenin. Protein Sci 2014; 24:525-33. [PMID: 25450558 DOI: 10.1002/pro.2613] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 11/25/2014] [Indexed: 11/11/2022]
Abstract
Molecular recognition models of both induced fit and conformational selection rely on coupled networks of flexible residues and/or structural rearrangements to promote protein function. While the atomic details of these motional events still remain elusive, members of the pancreatic ribonuclease superfamily were previously shown to depend on subtle conformational heterogeneity for optimal catalytic function. Human angiogenin, a structural homologue of bovine pancreatic RNase A, induces blood vessel formation and relies on a weak yet functionally mandatory ribonucleolytic activity to promote neovascularization. Here, we use the NMR chemical shift projection analysis (CHESPA) to clarify the mechanism of ligand binding in human angiogenin, further providing information on long-range intramolecular residue networks potentially involved in the function of this enzyme. We identify two main clusters of residue networks displaying correlated linear chemical shift trajectories upon binding of substrate fragments to the purine- and pyrimidine-specific subsites of the catalytic cleft. A large correlated residue network clusters in the region corresponding to the V1 domain, a site generally associated with the angiogenic response and structural stability of the enzyme. Another correlated network (residues 40-42) negatively affects the catalytic activity but also increases the angiogenic activity. (15) N-CPMG relaxation dispersion experiments could not reveal the existence of millisecond timescale conformational exchange in this enzyme, a lack of flexibility supported by the very low-binding affinities and catalytic activity of angiogenin. Altogether, the current report potentially highlights the existence of long-range dynamic reorganization of the structure upon distinct subsite binding events in human angiogenin.
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Affiliation(s)
- Donald Gagné
- INRS-Institut Armand-Frappier, Université du Québec, 531 Boulevard des Prairies, Laval, Québec, H7V 1B7, Canada
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Structural and molecular insights into the mechanism of action of human angiogenin-ALS variants in neurons. Nat Commun 2013; 3:1121. [PMID: 23047679 PMCID: PMC3493651 DOI: 10.1038/ncomms2126] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 09/06/2012] [Indexed: 12/11/2022] Open
Abstract
Mutations in angiogenin (ANG), a member of the ribonuclease A superfamily, are associated with amyotrophic lateral sclerosis (ALS; sporadic and familial) and Parkinson's disease. We have previously shown that ANG is expressed in neurons during neuro-ectodermal differentiation, and that it has both neurotrophic and neuroprotective functions. Here we report the atomic resolution structure of native ANG and 11 ANG-ALS variants. We correlate the structural changes to the effects on neuronal survival and the ability to induce stress granules in neuronal cell lines. ANG-ALS variants that affect the structure of the catalytic site and either decrease or increase the RNase activity affect neuronal survival. Neuronal cell lines expressing the ANG-ALS variants also lack the ability to form stress granules. Our structure–function studies on these ANG-ALS variants are the first to provide insights into the cellular and molecular mechanisms underlying their role in ALS. Mutations in human angiogenin are implicated in the progression of amyotrophic lateral sclerosis. Thiyagarajan and colleagues show that structural differences between angiogenin variants affect neuronal survival, and the ability to induce stress granules in neuronal cell lines.
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Thiyagarajan N, Acharya KR. Crystal structure of human angiogenin with an engineered loop exhibits conformational flexibility at the functional regions of the molecule. FEBS Open Bio 2012; 3:65-70. [PMID: 23772376 PMCID: PMC3668512 DOI: 10.1016/j.fob.2012.12.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 12/19/2012] [Accepted: 12/19/2012] [Indexed: 11/18/2022] Open
Abstract
Human angiogenin (ANG) is an angiogenic molecule and a ribonucleolytic enzyme with significant amino acid sequence identity to pancreatic RNase A, plays a critical role in the establishment and growth of tumours. An association between ANG and cancer has been observed in more than 25 clinical studies to date. In addition, ANG has now been shown to be implicated in Amyotrophic Lateral Sclerosis (ALS) and Parkinson's Disease (PD). Structural and biochemical studies so far have showed several distinguishing features of ANG molecule compared to RNase A and provided details of the putative cell binding site, active site, nuclear translocation sequence and the roles of residues in binding and cleaving RNA. A key finding elucidated from the structural study on ANG is the presence of a 'blocked' C-terminus (part of the active site apparatus) compared with RNase A. Here we report the crystal structure of ANG with an 'engineered-loop' from eosinophil derived neurotoxin (a homologue of ANG) which has resulted with local perturbations (conformational flexibility) at the cell binding site and at the C-terminus of the molecule. This experimental observation will now provide a new avenue to design compounds (potent inhibitors) through a structure guided drug design route.
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Affiliation(s)
| | - K. Ravi Acharya
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
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31
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Trouillon R, O'Hare D, Chang SI. An electrochemical functional assay for the sensing of nitric oxide release induced by angiogenic factors. BMB Rep 2011; 44:699-704. [PMID: 22118534 DOI: 10.5483/bmbrep.2011.44.11.699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nitric oxide (NO) is a critical biological mediator involved in numerous diseases. However, the short lifetime of this molecule in biological conditions can make its study in situ complicated. Here, we review some recent results on the role of NO in angiogenesis, obtained using a biocompatible microelectrode array. This simple system allowed for the quick and easy quantification of NO released from cells grown directly on the surface of the sensor. We have used this technology to demonstrate that angiogenin induces NO release, and to partially elucidate its intracellular transduction pathway.
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Trouillon R, Kang DK, Chang SI, O'Hare D. Angiogenin induces nitric oxide release independently from its RNase activity. Chem Commun (Camb) 2011; 47:3421-3. [DOI: 10.1039/c0cc04527f] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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Codoñer FM, Alfonso-Loeches S, Fares MA. Mutational dynamics of murine angiogenin duplicates. BMC Evol Biol 2010; 10:310. [PMID: 20950426 PMCID: PMC2964713 DOI: 10.1186/1471-2148-10-310] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Accepted: 10/15/2010] [Indexed: 12/03/2022] Open
Abstract
Background Angiogenin (Ang) is a protein involved in angiogenesis by inducing the formation of blood vessels. The biomedical importance of this protein has come from findings linking mutations in Ang to cancer progression and neurodegenerative diseases. These findings highlight the evolutionary constrain on Ang amino acid sequence. However, previous studies comparing human Angiogenin with homologs from other phylogenetically related organisms have led to the conclusion that Ang presents a striking variability. Whether this variability has an adaptive value per se remains elusive. Understanding why many functional Ang paralogs have been preserved in mouse and rat and identifying functional divergence mutations at these copies may explain the relationship between mutations and function. In spite of the importance of testing this hypothesis from the evolutionarily and biomedical perspectives, this remains yet unaccomplished. Here we test the main mutational dynamics driving the evolution and function of Ang paralogs in mammals. Results We analysed the phylogenetic asymmetries between the different Ang gene copies in mouse and rat in the context of vertebrate Ang phylogeny. This analysis shows strong evidence in support of accelerated evolution in some Ang murine copies (mAng). This acceleration is not due to non-functionalisation because constraints on amino acid replacements remain strong. We identify many of the amino acid sites involved in signal localization and nucleotide binding by Ang to have evolved under diversifying selection. Compensatory effects of many of the mutations at these paralogs and their key structural location in or nearby important functional regions support a possible functional shift (functional divergence) in many Ang copies. Similarities between 3D-structural models for mAng copies suggest that their divergence is mainly functional. Conclusions We identify the main evolutionary dynamics shaping the variability of Angiogenin in vertebrates and highlight the plasticity of this protein after gene duplication. Our results suggest functional divergence among mAng paralogs. This puts forward mAng as a good system candidate for testing functional plasticity of such an important protein while stresses caution when using mouse as a model to infer the consequences of mutations in the single Ang copy of humans.
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Affiliation(s)
- Francisco M Codoñer
- Evolutionary Genetics and Bioinformatics Laboratory, Department of Genetics, Smurfit Institute of Genetics, University of Dublin, Trinity College, Dublin, Ireland
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Tomecki R, Dziembowski A. Novel endoribonucleases as central players in various pathways of eukaryotic RNA metabolism. RNA (NEW YORK, N.Y.) 2010; 16:1692-1724. [PMID: 20675404 PMCID: PMC2924532 DOI: 10.1261/rna.2237610] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
For a long time it has been assumed that the decay of RNA in eukaryotes is mainly carried out by exoribonucleases, which is in contrast to bacteria, where endoribonucleases are well documented to initiate RNA degradation. In recent years, several as yet unknown endonucleases have been described, which has changed our view on eukaryotic RNA metabolism. Most importantly, it was shown that the primary eukaryotic 3' --> 5' exonuclease, the exosome complex has the ability to endonucleolytically cleave its physiological RNA substrates, and novel endonucleases involved in both nuclear and cytoplasmic RNA surveillance pathways were discovered concurrently. In addition, endoribonucleases responsible for long-known processing steps in the maturation pathways of various RNA classes were recently identified. Moreover, one of the most intensely studied RNA decay pathways--RNAi--is controlled and stimulated by the action of different endonucleases. Furthermore, endoribonucleolytic cleavages executed by various enzymes are also the hallmark of RNA degradation and processing in plant chloroplasts. Finally, multiple context-specific endoribonucleases control qualitative and/or quantitative changes of selected transcripts under particular conditions in different eukaryotic organisms. The aim of this review is to discuss the impact of all of these discoveries on our current understanding of eukaryotic RNA metabolism.
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Affiliation(s)
- Rafal Tomecki
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, University of Warsaw, 02-106 Warsaw, Poland
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The eight human "canonical" ribonucleases: molecular diversity, catalytic properties, and special biological actions of the enzyme proteins. FEBS Lett 2010; 584:2194-200. [PMID: 20388512 DOI: 10.1016/j.febslet.2010.04.018] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 04/07/2010] [Accepted: 04/07/2010] [Indexed: 01/25/2023]
Abstract
Human ribonucleases (RNases) are members of a large superfamily of rapidly evolving homologous proteins. Upon completion of the human genome, eight catalytically active RNases (numbered 1-8) were identified. These structurally distinct RNases, characterized by their various catalytic differences on different RNA substrates, constitute a gene family that appears to be the sole vertebrate-specific enzyme family. Apart from digestion of dietary RNA, a wide variety of biological actions, including neurotoxicity, angiogenesis, immunosuppressivity, and anti-pathogen activity, have been recently reported for almost all members of the family. Recent evolutionary studies suggest that RNases started off in vertebrates as host defence or angiogenic proteins.
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Trouillon R, Kang DK, Park H, Chang SI, O’Hare D. Angiogenin Induces Nitric Oxide Synthesis in Endothelial Cells through PI-3 and Akt Kinases. Biochemistry 2010; 49:3282-8. [DOI: 10.1021/bi902122w] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Raphaël Trouillon
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Dong-Ku Kang
- Department of Biochemistry, Chungbuk National University, Cheongju, Republic of Korea
| | - Hyun Park
- Department of Biochemistry, Chungbuk National University, Cheongju, Republic of Korea
| | - Soo-Ik Chang
- Department of Biochemistry, Chungbuk National University, Cheongju, Republic of Korea
| | - Danny O’Hare
- Department of Bioengineering, Imperial College London, London, United Kingdom
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Li S, Hu GF. Angiogenin-mediated rRNA transcription in cancer and neurodegeneration. INTERNATIONAL JOURNAL OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2010; 1:26-35. [PMID: 20827423 PMCID: PMC2933922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Accepted: 05/05/2010] [Indexed: 05/29/2023]
Abstract
Angiogenin (ANG) is a 14 kDa angiogenic ribonuclease that is upregulated in a variety of human cancers. Accumulating evidence indicates that the angiogenic activity of ANG is related to its ability in regulating ribosomal RNA (rRNA) transcription. ANG is translocated to the nucleus of growth-stimulated endothelial cells where it accumulates in the nucleolus, binds to the promoter region of ribosomal DNA (rDNA), and stimulates rRNA transcription. This normally well-controlled process of nuclear translocation of ANG is hijacked by cancer cells that constitutively uptake ANG and translocate it into the nucleus so that rRNA is constantly transcribed to meet a higher metabolic requirement of this cells. Nuclear translocation of ANG therefore controls the rate of rRNA transcription and has been shown to be a molecular target for cancer drug development. Recently, ANG has also been shown to play a role in motor neuron physiology. Loss-of-function mutations in the coding region of ANG gene have been found in patients with amyotrophic lateral sclerosis (ALS). A deficiency in ANG function may result in insufficient rRNA transcription in motor neurons that require robust ribosome biogenesis due to the demand of long axonal transport. Haploinsufficiency of ANG has thus been implicated in ALS pathogenesis, and ANG has been shown to promote motor neuron survival both in vitro and in vivo. Promotion of ANG expression or activity has been recognized as a therapeutic opportunity for ALS treatment.
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Affiliation(s)
- Shuping Li
- Department of Pathology, Harvard Medical School, 77 Avenue Louis Pasteur, MA 02115, USA
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Abstract
The efficient turnover of messenger RNA represents an important mechanism that allows the cell to control gene expression. Until recently, the mechanism of mRNA decay was mainly attributed to exonucleases, comprising enzymes that degrade RNAs from the ends of the molecules. This article summarizes the endoribonucleases, comprising enzymes that cleave RNA molecules internally, which were identified in more recent years in eukaryotic mRNA metabolism. Endoribonucleases have received little attention in the past, based on the difficulty in their identification and a lack of understanding of their physiological significance. This review aims to compare the similarities and differences among this group of enzymes, as well as their known cellular functions. Despite the many differences in protein structure, and thus difficulties in identifying them based on amino acid sequence, most endoribonucleases possess essential cellular functions and have been shown to play an important role in mRNA turnover.
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Affiliation(s)
- Wai Ming Li
- Chemistry Program, University of Northern British Columbia, Prince George, BC, Canada
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Monti DM, Yu W, Pizzo E, Shima K, Hu MG, Di Malta C, Piccoli R, D'Alessio G, Hu GF. Characterization of the angiogenic activity of zebrafish ribonucleases. FEBS J 2009; 276:4077-90. [PMID: 19549190 DOI: 10.1111/j.1742-4658.2009.07115.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Ribonucleases identified from zebrafish possess angiogenic and bactericidal activities. Zebrafish RNases have three intramolecular disulfide bonds, a characteristic structural feature of angiogenin, different from the typical four disulfide bonds of the other members of the RNase A superfamily. They also have a higher degree of sequence homology to angiogenin than to RNase A. It has been proposed that all RNases evolved from these angiogenin-like progenitors. In the present study, we characterize, in detail, the function of zebrafish RNases in various steps in the process of angiogenesis. We report that zebrafish RNase-1, -2 and -3 bind to the cell surface specifically and are able to compete with human angiogenin. Similar to human angiogenin, all three zebrafish RNases are able to induce phosphorylation of extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase. They also undergo nuclear translocation, accumulate in the nucleolus and stimulate rRNA transcription. However, zebrafish RNase-3 is defective in cleaving rRNA precursor, even though it has been reported to have an open active site and has higher enzymatic activity toward more classic RNase substrates such as yeast tRNA and synthetic oligonucleotides. Taken together with the findings that zebrafish RNase-3 is less angiogenic than zebrafish RNase-1 and -2 as well as human angiogenin, these results suggest that zebrafish RNase-1 is the ortholog of human angiogenin and that the ribonucleolytic activity of zebrafish RNases toward the rRNA precursor substrate is functionally important for their angiogenic activity.
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Affiliation(s)
- Daria M Monti
- Department of Structural and Functional Biology, University of Naples Federico II, Italy
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Kishikawa H, Wu D, Hu GF. Targeting angiogenin in therapy of amyotropic lateral sclerosis. Expert Opin Ther Targets 2008; 12:1229-42. [PMID: 18781822 DOI: 10.1517/14728222.12.10.1229] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Missense heterozygous mutations in the coding region of angiogenin (ANG) gene, encoding a 14 kDa angiogenic RNase, were recently found in patients of amyotropic lateral sclerosis (ALS). Functional analyses have shown that these are loss-of-function mutations, implying that angiogenin deficiency is associated with ALS pathogenesis and that increasing ANG expression or angiogenin activity could be a novel approach for ALS therapy. OBJECTIVE Review the evidence showing the involvement of angiogenin in motor neuron physiology and function, and provide a rationale for targeting angiogenin in ALS therapy. METHODS Review the current understanding of the mechanism of angiogenin action in connection with ALS genetics, pathogenesis and therapy. CONCLUSION ANG is the first gene whose loss-of-function mutations are associated with ALS pathogenesis. Therapeutic modulation of angiogenin level and activity in the spinal cord, either by systemic delivery of angiogenin protein or through retrograde transport of ANG-encoding viral particles, may be beneficial for ALS patients.
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Affiliation(s)
- Hiroko Kishikawa
- Harvard Medical School, Department of Pathology, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
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Abstract
Angiogenin induces angiogenesis by activating vessel endothelial and smooth muscle cells and triggering a number of biological processes, including cell migration, invasion, proliferation, and formation of tubular structures. It has been reported that angiogenin plays its functions mainly through four pathways: (1) exerting its ribonucleolytic activity; (2) binding to membrane actin and then inducing basement membrane degradation; (3) binding to a putative 170-kDa protein and subsequently transducing signal into cytoplasm; and (4) translocating into the nucleus of target cells directly and then enhancing ribosomal RNA transcription. Angiogenin can also translocate into the nucleus of cancer cells and induces the corresponding cell proliferation. Furthermore, angiogenin has neuroprotective activities in the central nervous system and the loss of its function may be related to amyotrophic lateral sclerosis. This review intends to conclude the mechanisms underlying these actions of angiogenin and give a perspective on future research.
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Affiliation(s)
- Xiangwei Gao
- Research Center for Environmental Genomics, Bioelectromagnetics Laboratory, Zhejiang University School of Medicine, Hangzhou 310058, China
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Kazakou K, Holloway DE, Prior SH, Subramanian V, Acharya KR. Ribonuclease A homologues of the zebrafish: polymorphism, crystal structures of two representatives and their evolutionary implications. J Mol Biol 2008; 380:206-22. [PMID: 18508078 PMCID: PMC2582337 DOI: 10.1016/j.jmb.2008.04.070] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 04/24/2008] [Accepted: 04/27/2008] [Indexed: 12/21/2022]
Abstract
The widespread and functionally varied members of the ribonuclease A (RNase A) superfamily provide an excellent opportunity to study evolutionary forces at work on a conserved protein scaffold. Representatives from the zebrafish are of particular interest as the evolutionary distance from non-ichthyic homologues is large. We conducted an exhaustive survey of available zebrafish DNA sequences and found significant polymorphism among its four known homologues. In an extension of previous nomenclature, the variants have been named RNases ZF-1a–c,-2a–d,-3a–e and-4. We present the first X-ray crystal structures of zebrafish ribonucleases, RNases ZF-1a and-3e at 1.35-and 1.85 Å resolution, respectively. Structure-based clustering with ten other ribonuclease structures indicates greatest similarity to mammalian angiogenins and amphibian ribonucleases, and supports the view that all present-day ribonucleases evolved from a progenitor with three disulphide bonds. In their details, the two structures are intriguing melting-pots of features present in ribonucleases from other vertebrate classes. Whereas in RNase ZF-1a the active site is obstructed by the C-terminal segment (as observed in angiogenin), in RNase ZF-3e the same region is open (as observed in more catalytically efficient homologues). The progenitor of present-day ribonucleases is more likely to have had an obstructive C terminus, and the relatively high similarity (late divergence) of RNases ZF-1 and-3 infers that the active site unblocking event has happened independently in different vertebrate lineages.
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Tello-Montoliu A, Patel JV, Lip GYH. Angiogenin: a review of the pathophysiology and potential clinical applications. J Thromb Haemost 2006; 4:1864-74. [PMID: 16961595 DOI: 10.1111/j.1538-7836.2006.01995.x] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Angiogenin is a member of the ribonuclease (RNase) superfamily: enzymes of innate substrate specificity, but divergent functional capacities. Angiogenin is a normal constituent of the circulation and contained in a vasculature that rarely undergoes proliferation, but in some physiological and pathological conditions its levels increase in blood, promoting neovascularization. Hence, angiogenesis is a common pathophysiological attribute of angiogenin. In malignant disease, the most studied pathological state in regard to angionenin, abnormally high levels are seen, which may be of prognostic significance. Angiogenin has also been studied in other non-malignant pathological states. The aim of this review article is to provide an overview of the biochemistry and physiology of angiogenin, specifically in relation to the human pathological states where angiogenin has been implicated and finally, its potential clinical applications.
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Affiliation(s)
- A Tello-Montoliu
- Haemostasis, Thrombosis and Vascular Biology Unit, University Department of Medicine, City Hospital, Birmingham, UK
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Holloway DE, Chavali GB, Hares MC, Subramanian V, Acharya KR. Structure of murine angiogenin: features of the substrate- and cell-binding regions and prospects for inhibitor-binding studies. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2005; 61:1568-78. [PMID: 16301790 PMCID: PMC1780170 DOI: 10.1107/s0907444905029616] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2005] [Accepted: 09/18/2005] [Indexed: 11/10/2022]
Abstract
Angiogenin is an unusual member of the pancreatic ribonuclease superfamily that induces blood-vessel formation and is a promising anticancer target. The three-dimensional structure of murine angiogenin (mAng) has been determined by X-ray crystallography. Two structures are presented: one is a complex with sulfate ions (1.5 Angstroms resolution) and the other a complex with phosphate ions (1.6 Angstroms resolution). Residues forming the putative B(1), P(1) and B(2) subsites occupy positions similar to their hAng counterparts and are likely to play similar roles. The anions occupy the P(1) subsite, sulfate binding conventionally and phosphate adopting two orientations, one of which is novel. The B(1) subsite is obstructed by Glu116 and Phe119, with the latter assuming a less invasive position than its hAng counterpart. Hydrophobic interactions between the C-terminal segment and the main body of the protein are more extensive than in hAng and may underly the lower enzymatic activity of the murine protein. Elsewhere, the structure of the H3-B2 loop supports the view that hAng Asn61 interacts directly with cell-surface molecules and does not merely stabilize adjacent regions of the hAng structure. mAng crystals appear to offer small-molecule inhibitors a clear route to the active site and may even withstand a reorientation of the C-terminal segment that provides access to the cryptic B(1) subsite. These features represent considerable advantages over crystalline hAng and bAng.
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Arndt MAE, Krauss J, Vu BK, Newton DL, Rybak SM. A Dimeric Angiogenin Immunofusion Protein Mediates Selective Toxicity Toward CD22+ Tumor Cells. J Immunother 2005; 28:245-51. [PMID: 15838381 DOI: 10.1097/01.cji.0000161396.96582.10] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
To improve selective cytotoxicity and pharmacokinetics of an anti-CD22 antibody single chain Fv (scFv)-ribonuclease fusion protein, a dimeric derivative was generated. Human angiogenin was fused via a (G4S)3 spacer peptide to the carboxy-terminal end of the stable dimeric anti-CD22 VL-VH zero-linker scFv MLT-7. The dimeric fusion protein and a monovalent counterpart were produced as soluble proteins in the periplasm of Escherichia coli. Comparative studies with homogeneously purified fusion proteins revealed that both constructs specifically bound to the target antigen and retained ribonucleolytic activity. However, they exhibited a markedly different capability for killing CD22+ tumor cells. The monomeric construct inhibited protein synthesis of target cells in a dose-dependent manner, but 50% inhibition (IC50) could be achieved only at the highest tested concentration (>350 nM). In contrast, the dimeric fusion protein efficiently killed CD22+ Raji and Daudi tumor cell lines with IC50 values of 74 nM and 118 nM, respectively. These results show that the therapeutic potential of scFv-ANG fusion proteins can be markedly enhanced by engineering dimeric derivatives.
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Quantitation of Amino Acids as 6-Aminoquinolyl-N-hydroxysuccinimidyl Carbamate Derivatives. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s0301-4770(05)80011-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
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Kumar K, Jenkins JL, Jardine AM, Shapiro R. Inhibition of mammalian ribonucleases by endogenous adenosine dinucleotides. Biochem Biophys Res Commun 2003; 300:81-6. [PMID: 12480524 DOI: 10.1016/s0006-291x(02)02800-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The most potent low molecular weight inhibitors of pancreatic RNase superfamily enzymes reported to date are synthetic derivatives of adenosine 5(')-pyrophosphate. Here we have investigated the effects of six natural nucleotides that also incorporate this moiety (NADP(+), NADPH, ATP, Ap(3)A, Ap(4)A, and Ap(5)A) on the activities of RNase A and two of its homologues, eosinophil-derived neurotoxin and angiogenin. With eosinophil-derived neurotoxin and angiogenin, Ap(5)A is comparable to the tightest binding inhibitors identified previously (K(i) values at pH 5.9 are 370 nM and 100 microM, respectively); it ranks among the strongest small antagonists of RNase A as well (K(i)=230 nM). The K(i) for NADPH with angiogenin is similar to that of Ap(5)A. These findings suggest that Ap(5)A and NADPH may serve as useful new leads for inhibitor design. Examination of inhibition under physiological conditions indicates that NADPH, ATP, and Ap(5)A may suppress intracellular RNase activity significantly in vivo.
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Affiliation(s)
- Kapil Kumar
- Center for Biochemical and Biophysical Sciences and Medicine, Harvard Medical School, One Kendall Square, Building 600, Third Floor, Cambridge, MA 02139, USA
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Jenkins JL, Kao RYT, Shapiro R. Virtual screening to enrich hit lists from high-throughput screening: a case study on small-molecule inhibitors of angiogenin. Proteins 2003; 50:81-93. [PMID: 12471601 DOI: 10.1002/prot.10270] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
"Hit lists" generated by high-throughput screening (HTS) typically contain a large percentage of false positives, making follow-up assays necessary to distinguish active from inactive substances. Here we present a method for improving the accuracy of HTS hit lists by computationally based virtual screening (VS) of the corresponding chemical libraries and selecting hits by HTS/VS consensus. This approach was applied in a case study on the target-enzyme angiogenin, a potent inducer of angiogenesis. In conjunction with HTS of the National Cancer Institute Diversity Set and ChemBridge DIVERSet E (approximately 18,000 compounds total), VS was performed with two flexible library docking/scoring methods, DockVision/Ludi and GOLD. Analysis of the results reveals that dramatic enrichment of the HTS hit rate can be achieved by selecting compounds in consensus with one or both of the VS functions. For example, HTS hits ranked in the top 2% by GOLD included 42% of the true hits, but only 8% of the false positives; this represents a sixfold enrichment over the HTS hit rate. Notably, the HTS/VS method was effective in selecting out inhibitors with midmicromolar dissociation constants typical of leads commonly obtained in primary screens.
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Affiliation(s)
- Jeremy L Jenkins
- Center for Biochemical and Biophysical Sciences and Medicine, Harvard Medical School, Cambridge, Massachusetts 02139, USA
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Kao RYT, Jenkins JL, Olson KA, Key ME, Fett JW, Shapiro R. A small-molecule inhibitor of the ribonucleolytic activity of human angiogenin that possesses antitumor activity. Proc Natl Acad Sci U S A 2002; 99:10066-71. [PMID: 12118120 PMCID: PMC126625 DOI: 10.1073/pnas.152342999] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The results of previous preclinical and clinical studies have identified angiogenin (ANG) as a potentially important target for anticancer therapy. Here we report the design and implementation of a high-throughput screening assay to identify small molecules that bind to the ribonucleolytic active site of ANG, which is critically involved in the induction of angiogenesis by this protein. Screening of 18,310 compounds from the National Cancer Institute (NCI) Diversity Set and ChemBridge DIVERSet yielded 15 hits that inhibit the enzymatic activity of ANG with K(i) values <100 microM. One of these, NCI compound 65828 [8-amino-5-(4'-hydroxybiphenyl-4-ylazo)naphthalene-2-sulfonate; K(i) = 81 microM], was selected for more detailed studies. Minor changes in ANG or ligand structure markedly reduced potency, demonstrating that inhibition reflects active-site rather than nonspecific binding; these observations are consistent with a computationally generated model of the ANG.65828 complex. Local treatment with modest doses of 65828 significantly delayed the formation of s.c. tumors from two distinct human cancer cell types in athymic mice. ANG is the likely target involved because (i) a 65828 analogue with much lower potency against the enzymatic activity of ANG failed to exert any antitumor effect, (ii) tumors from 65828-treated mice had fewer interior blood vessels than those from control mice, and (iii) 65828 appears to have no direct effect on the tumor cells. Our findings provide considerable support for the targeting of the enzymatic active site of ANG as a strategy for developing new anticancer drugs.
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Affiliation(s)
- Richard Y T Kao
- Center for Biochemical and Biophysical Sciences, Harvard Medical School, Cambridge, MA 02139, USA
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