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Dubovskii PV, Ignatova AA, Alekseeva AS, Starkov VG, Boldyrev IA, Feofanov AV, Utkin YN. Membrane-Disrupting Activity of Cobra Cytotoxins Is Determined by Configuration of the N-Terminal Loop. Toxins (Basel) 2022; 15:6. [PMID: 36668826 PMCID: PMC9866941 DOI: 10.3390/toxins15010006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/15/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
In aqueous solutions, cobra cytotoxins (CTX), three-finger folded proteins, exhibit conformational equilibrium between conformers with either cis or trans peptide bonds in the N-terminal loop (loop-I). The equilibrium is shifted to the cis form in toxins with a pair of adjacent Pro residues in this loop. It is known that CTX with a single Pro residue in loop-I and a cis peptide bond do not interact with lipid membranes. Thus, if a cis peptide bond is present in loop-I, as in a Pro-Pro containing CTX, this should weaken its lipid interactions and likely cytotoxic activities. To test this, we have isolated seven CTX from Naja naja and N. haje cobra venoms. Antibacterial and cytotoxic activities of these CTX, as well as their capability to induce calcein leakage from phospholipid liposomes, were evaluated. We have found that CTX with a Pro-Pro peptide bond indeed exhibit attenuated membrane-perturbing activity in model membranes and lower cytotoxic/antibacterial activity compared to their counterparts with a single Pro residue in loop-I.
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Affiliation(s)
- Peter V. Dubovskii
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Anastasia A. Ignatova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Anna S. Alekseeva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Vladislav G. Starkov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Ivan A. Boldyrev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Alexey V. Feofanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Bioengineering Department, Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Yuri N. Utkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
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Li F, Shrivastava IH, Hanlon P, Dagda RK, Gasanoff ES. Molecular Mechanism by which Cobra Venom Cardiotoxins Interact with the Outer Mitochondrial Membrane. Toxins (Basel) 2020; 12:E425. [PMID: 32605112 PMCID: PMC7404710 DOI: 10.3390/toxins12070425] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/23/2020] [Accepted: 06/26/2020] [Indexed: 12/29/2022] Open
Abstract
Cardiotoxin CTII from Najaoxiana cobra venom translocates to the intermembrane space (IMS) of mitochondria to disrupt the structure and function of the inner mitochondrial membrane. At low concentrations, CTII facilitates ATP-synthase activity, presumably via the formation of non-bilayer, immobilized phospholipids that are critical in modulating ATP-synthase activity. In this study, we investigated the effects of another cardiotoxin CTI from Najaoxiana cobra venom on the structure of mitochondrial membranes and on mitochondrial-derived ATP synthesis. By employing robust biophysical methods including 31P-NMR and 1H-NMR spectroscopy, we analyzed the effects of CTI and CTII on phospholipid packing and dynamics in model phosphatidylcholine (PC) membranes enriched with 2.5 and 5.0 mol% of cardiolipin (CL), a phospholipid composition that mimics that in the outer mitochondrial membrane (OMM). These experiments revealed that CTII converted a higher percentage of bilayer phospholipids to a non-bilayer and immobilized state and both cardiotoxins utilized CL and PC molecules to form non-bilayer structures. Furthermore, in order to gain further understanding on how cardiotoxins bind to mitochondrial membranes, we employed molecular dynamics (MD) and molecular docking simulations to investigate the molecular mechanisms by which CTII and CTI interactively bind with an in silico phospholipid membrane that models the composition similar to the OMM. In brief, MD studies suggest that CTII utilized the N-terminal region to embed the phospholipid bilayer more avidly in a horizontal orientation with respect to the lipid bilayer and thereby penetrate at a faster rate compared with CTI. Molecular dynamics along with the Autodock studies identified critical amino acid residues on the molecular surfaces of CTII and CTI that facilitated the long-range and short-range interactions of cardiotoxins with CL and PC. Based on our compiled data and our published findings, we provide a conceptual model that explains a molecular mechanism by which snake venom cardiotoxins, including CTI and CTII, interact with mitochondrial membranes to alter the mitochondrial membrane structure to either upregulate ATP-synthase activity or disrupt mitochondrial function.
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Affiliation(s)
- Feng Li
- STEM Program, Science Department, Chaoyang KaiWen Academy, Yard 46, 3rd Baoquan Street, Chaoyang District, Beijing 100018, China; (F.L.); (P.H.); (E.S.G.)
| | - Indira H. Shrivastava
- Department of Computational and System Biology, University of Pittsburgh, Pittsburgh, PA 15260, USA;
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Paul Hanlon
- STEM Program, Science Department, Chaoyang KaiWen Academy, Yard 46, 3rd Baoquan Street, Chaoyang District, Beijing 100018, China; (F.L.); (P.H.); (E.S.G.)
| | - Ruben K. Dagda
- Reno School of Medicine, Department of Pharmacology, University of Nevada, Reno, NV 89557, USA
| | - Edward S. Gasanoff
- STEM Program, Science Department, Chaoyang KaiWen Academy, Yard 46, 3rd Baoquan Street, Chaoyang District, Beijing 100018, China; (F.L.); (P.H.); (E.S.G.)
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Chiou JT, Shi YJ, Wang LJ, Huang CH, Lee YC, Chang LS. Naja atra Cardiotoxin 3 Elicits Autophagy and Apoptosis in U937 Human Leukemia Cells through the Ca 2+/PP2A/AMPK Axis. Toxins (Basel) 2019; 11:toxins11090527. [PMID: 31547294 PMCID: PMC6784133 DOI: 10.3390/toxins11090527] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 09/04/2019] [Accepted: 09/10/2019] [Indexed: 12/22/2022] Open
Abstract
Cardiotoxins (CTXs) are suggested to exert their cytotoxicity through cell membrane damage. Other studies show that penetration of CTXs into cells elicits mitochondrial fragmentation or lysosome disruption, leading to cell death. Considering the role of AMPK-activated protein kinase (AMPK) in mitochondrial biogenesis and lysosomal biogenesis, we aimed to investigate whether the AMPK-mediated pathway modulated Naja atra (Taiwan cobra) CTX3 cytotoxicity in U937 human leukemia cells. Our results showed that CTX3 induced autophagy and apoptosis in U937 cells, whereas autophagic inhibitors suppressed CTX3-induced apoptosis. CTX3 treatment elicited Ca2+-dependent degradation of the protein phosphatase 2A (PP2A) catalytic subunit (PP2Acα) and phosphorylation of AMPKα. Overexpression of PP2Acα mitigated the CTX3-induced AMPKα phosphorylation. CTX3-induced autophagy was via AMPK-mediated suppression of the Akt/mTOR pathway. Removal of Ca2+ or suppression of AMPKα phosphorylation inhibited the CTX3-induced cell death. CTX3 was unable to induce autophagy and apoptosis in U937 cells expressing constitutively active Akt. Met-modified CTX3 retained its membrane-perturbing activity, however, it did not induce AMPK activation and death of U937 cells. These results conclusively indicate that CTX3 induces autophagy and apoptosis in U937 cells via the Ca2+/PP2A/AMPK axis, and suggest that the membrane-perturbing activity of CTX3 is not crucial for the cell death signaling pathway induction.
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Affiliation(s)
- Jing-Ting Chiou
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
| | - Yi-Jun Shi
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
| | - Liang-Jun Wang
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
| | - Chia-Hui Huang
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
| | - Yuan-Chin Lee
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
| | - Long-Sen Chang
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
- Department of Biotechnology, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
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Kuraoka M, Kimura E, Nagata T, Okada T, Aoki Y, Tachimori H, Yonemoto N, Imamura M, Takeda S. Serum Osteopontin as a Novel Biomarker for Muscle Regeneration in Duchenne Muscular Dystrophy. Am J Pathol 2016; 186:1302-12. [PMID: 26963343 DOI: 10.1016/j.ajpath.2016.01.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 12/25/2015] [Accepted: 01/05/2016] [Indexed: 12/20/2022]
Abstract
Duchenne muscular dystrophy is a lethal X-linked muscle disorder. We have already reported that osteopontin (OPN), an inflammatory cytokine and myogenic factor, is expressed in the early dystrophic phase in canine X-linked muscular dystrophy in Japan, a dystrophic dog model. To further explore the possibility of OPN as a new biomarker for disease activity in Duchenne muscular dystrophy, we monitored serum OPN levels in dystrophic and wild-type dogs at different ages and compared the levels to other serum markers, such as serum creatine kinase, matrix metalloproteinase-9, and tissue inhibitor of metalloproteinase-1. Serum OPN levels in the dystrophic dogs were significantly elevated compared with those in wild-type dogs before and 1 hour after a cesarean section birth and at the age of 3 months. The serum OPN level was significantly correlated with the phenotypic severity of dystrophic dogs at the period corresponding to the onset of muscle weakness, whereas other serum markers including creatine kinase were not. Immunohistologically, OPN was up-regulated in infiltrating macrophages and developmental myosin heavy chain-positive regenerating muscle fibers in the dystrophic dogs, whereas serum OPN was highly elevated. OPN expression was also observed during the synergic muscle regeneration process induced by cardiotoxin injection. In conclusion, OPN is a promising biomarker for muscle regeneration in dystrophic dogs and can be applicable to boys with Duchenne muscular dystrophy.
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Affiliation(s)
- Mutsuki Kuraoka
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - En Kimura
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan; Translational Medical Center, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Tetsuya Nagata
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan; Department of Neurology and Neurological Science, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takashi Okada
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan; Department of Biochemistry and Molecular Biology, Nippon Medical School, Tokyo, Japan
| | - Yoshitsugu Aoki
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Hisateru Tachimori
- Department of Mental Health Policy and Evaluation, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Naohiro Yonemoto
- Department of Psychopharmacology, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Michihiro Imamura
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Shin'ichi Takeda
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
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Chen YJ, Tsai CY, Hu WP, Chang LS. DNA Aptamers against Taiwan Banded Krait α-Bungarotoxin Recognize Taiwan Cobra Cardiotoxins. Toxins (Basel) 2016; 8:toxins8030066. [PMID: 26959062 PMCID: PMC4810211 DOI: 10.3390/toxins8030066] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 02/29/2016] [Accepted: 02/29/2016] [Indexed: 02/07/2023] Open
Abstract
Bungarus multicinctus α-bungarotoxin (α-Bgt) and Naja atra cardiotoxins (CTXs) share a common structural scaffold, and their tertiary structures adopt three-fingered loop motifs. Four DNA aptamers against α-Bgt have been reported previously. Given that the binding of aptamers with targeted proteins depends on structural complementarity, in this study, we investigated whether DNA aptamers against α-Bgt could also recognize CTXs. It was found that N.atra cardiotoxin 3 (CTX3) reduced the electrophoretic mobility of aptamers against α-Bgt. Analysis of the changes in the fluorescence intensity of carboxyfluorescein-labeled aptamers upon binding toxin molecules revealed that CTX3 and α-Bgt could bind the tested aptamers. Moreover, the aptamers inhibited the membrane-damaging activity and cytotoxicity of CTX3. In addition to CTX3, other N. atra CTX isotoxins also bound to the aptamer against α-Bgt. Taken together, our data indicate that aptamers against α-Bgt show cross-reactivity with CTXs. The findings that aptamers against α-Bgt also suppress the biological activities of CTX3 highlight the potential utility of aptamers in regard to the broad inhibition of snake venom three-fingered proteins.
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Affiliation(s)
- Ying-Jung Chen
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
| | - Chia-Yu Tsai
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
| | - Wan-Ping Hu
- Department of Biotechnology, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
| | - Long-Sen Chang
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
- Department of Biotechnology, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
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Hardy D, Besnard A, Latil M, Jouvion G, Briand D, Thépenier C, Pascal Q, Guguin A, Gayraud-Morel B, Cavaillon JM, Tajbakhsh S, Rocheteau P, Chrétien F. Comparative Study of Injury Models for Studying Muscle Regeneration in Mice. PLoS One 2016; 11:e0147198. [PMID: 26807982 PMCID: PMC4726569 DOI: 10.1371/journal.pone.0147198] [Citation(s) in RCA: 299] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 12/30/2015] [Indexed: 11/19/2022] Open
Abstract
Background A longstanding goal in regenerative medicine is to reconstitute functional tissus or organs after injury or disease. Attention has focused on the identification and relative contribution of tissue specific stem cells to the regeneration process. Relatively little is known about how the physiological process is regulated by other tissue constituents. Numerous injury models are used to investigate tissue regeneration, however, these models are often poorly understood. Specifically, for skeletal muscle regeneration several models are reported in the literature, yet the relative impact on muscle physiology and the distinct cells types have not been extensively characterised. Methods We have used transgenic Tg:Pax7nGFP and Flk1GFP/+ mouse models to respectively count the number of muscle stem (satellite) cells (SC) and number/shape of vessels by confocal microscopy. We performed histological and immunostainings to assess the differences in the key regeneration steps. Infiltration of immune cells, chemokines and cytokines production was assessed in vivo by Luminex®. Results We compared the 4 most commonly used injury models i.e. freeze injury (FI), barium chloride (BaCl2), notexin (NTX) and cardiotoxin (CTX). The FI was the most damaging. In this model, up to 96% of the SCs are destroyed with their surrounding environment (basal lamina and vasculature) leaving a “dead zone” devoid of viable cells. The regeneration process itself is fulfilled in all 4 models with virtually no fibrosis 28 days post-injury, except in the FI model. Inflammatory cells return to basal levels in the CTX, BaCl2 but still significantly high 1-month post-injury in the FI and NTX models. Interestingly the number of SC returned to normal only in the FI, 1-month post-injury, with SCs that are still cycling up to 3-months after the induction of the injury in the other models. Conclusions Our studies show that the nature of the injury model should be chosen carefully depending on the experimental design and desired outcome. Although in all models the muscle regenerates completely, the trajectories of the regenerative process vary considerably. Furthermore, we show that histological parameters are not wholly sufficient to declare that regeneration is complete as molecular alterations (e.g. cycling SCs, cytokines) could have a major persistent impact.
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Affiliation(s)
- David Hardy
- Institut Pasteur, Human histopathology and animal models Unit, Infection and Epidemiology Department, Paris, France
- Paris Est University, Créteil, France
| | - Aurore Besnard
- Institut Pasteur, Human histopathology and animal models Unit, Infection and Epidemiology Department, Paris, France
| | - Mathilde Latil
- Institut Pasteur, Human histopathology and animal models Unit, Infection and Epidemiology Department, Paris, France
| | - Grégory Jouvion
- Institut Pasteur, Human histopathology and animal models Unit, Infection and Epidemiology Department, Paris, France
- Paris Descartes University, Sorbonne Paris Cité, Paris France
| | - David Briand
- Institut Pasteur, Human histopathology and animal models Unit, Infection and Epidemiology Department, Paris, France
| | - Cédric Thépenier
- Institut Pasteur, Human histopathology and animal models Unit, Infection and Epidemiology Department, Paris, France
- IRBA, Unité Interactions Hôte-Agents Pathogènes, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France
| | - Quentin Pascal
- Institut Pasteur, Human histopathology and animal models Unit, Infection and Epidemiology Department, Paris, France
| | - Aurélie Guguin
- Inserm, U955, Plateforme de Cytométrie en Flux, Créteil, France
| | - Barbara Gayraud-Morel
- Institut Pasteur, Stem Cells & Development Unit, Department of Developmental & Stem Cell Biology, Paris, France
| | - Jean-Marc Cavaillon
- Institut Pasteur, Cytokines and Inflammation Unit, Infection and Epidemiology Department, Paris, France
| | - Shahragim Tajbakhsh
- Institut Pasteur, Stem Cells & Development Unit, Department of Developmental & Stem Cell Biology, Paris, France
| | - Pierre Rocheteau
- Institut Pasteur, Human histopathology and animal models Unit, Infection and Epidemiology Department, Paris, France
| | - Fabrice Chrétien
- Institut Pasteur, Human histopathology and animal models Unit, Infection and Epidemiology Department, Paris, France
- Paris Descartes University, Sorbonne Paris Cité, Paris France
- Centre Hospitalier Sainte Anne, Laboratoire de Neuropathologie, Paris, France
- * E-mail:
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Kao PH, Lin SR, Chang LS. Interaction of Naja naja atra cardiotoxin 3 with H-trisaccharide modulates its hemolytic activity and membrane-damaging activity. Toxicon 2010; 55:1387-95. [PMID: 20193704 DOI: 10.1016/j.toxicon.2010.02.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2009] [Revised: 01/19/2010] [Accepted: 02/16/2010] [Indexed: 11/16/2022]
Abstract
To address whether saccharide moieties of blood groups A, B and O antigens modulate hemolytic activity of Naja naja atra cardiotoxins (CTXs), the present study was carried out. Unlike other CTX isotoxins, hemolytic activity of CTX3 toward blood group O cholesterol-depleted red blood cells (RBCs) was notably lower than that of blood groups A and B cholesterol-depleted RBCs. Conversion of blood group B RBCs into blood group O RBCs by alpha-galactosidase treatment attenuated the susceptibility for hemolytic activity of CTX3, suggesting that H-antigen affected hemolytic potency of CTX3. Pre-incubation with H-trisaccharide reduced hemolytic activity and membrane-damaging activity of CTX3. Moreover, CTX3 showed a higher binding capability with H-trisaccharide than other CTXs did. CD spectra showed that the binding with H-trisaccharide induced changes in gross conformation of CTX3. Self-quenching studies revealed that oligomerization of CTX3 was affected in the presence of H-trisaccharide. Taken together, our data suggest that the binding of CTX3 with H-antigen alters its membrane-bound mode, thus reducing its hemolytic activity toward blood group O cholesterol-depleted RBCs.
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Affiliation(s)
- Pei-Hsiu Kao
- Institute of Biomedical Sciences, National Sun Yat-Sen University-Kaohsiung Medical University Joint Research Center, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
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Zhao Y, Urganus AL, Spevak L, Shrestha S, Doty SB, Boskey AL, Pachman LM. Characterization of dystrophic calcification induced in mice by cardiotoxin. Calcif Tissue Int 2009; 85:267-75. [PMID: 19690791 PMCID: PMC2830143 DOI: 10.1007/s00223-009-9271-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Accepted: 06/17/2009] [Indexed: 01/18/2023]
Abstract
Dystrophic calcifications often occur after injury, infection, or onset of certain rheumatic diseases. Treatment has been limited to surgical removal following failure of medical therapy. In an attempt to establish a reproducible animal model for dystrophic calcification that permitted the screening of potential interventions, we evaluated cardiotoxin (injury)-induced calcifications in three murine strains at both the cellular and ultrastructural levels. All osteopontin null mice and tumor necrosis factor receptor null mice on a C57B6 background had calcifications at days 3 and 7 after injury compared to 75% of wild-type C57B6 mice. There was no difference in mineral content among calcifications from the three mouse strains. Osteogenesis was suggested by the expression of osteocalcin, osterix, and alkaline phosphatase in calcified murine muscle tissue. Osteoclast-like cells facilitated the removal of transient dystrophic deposits (<28 days) in all models. However, none of the models showed an association of mineral crystals with collagen, suggesting that the deposits were not bone-like. The dystrophic mechanism was validated as cell death, and mitochondrial calcifications occurred soon after skeletal muscle injury in the three murine strains.
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Affiliation(s)
- Yongdong Zhao
- Center of Excellence in Clinical Immunology, Children's Memorial Research Center, 2300 Children's Plaza, Box 212, Chicago, IL 60614, USA, Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Annette L. Urganus
- Center of Excellence in Clinical Immunology, Children's Memorial Research Center, 2300 Children's Plaza, Box 212, Chicago, IL 60614, USA
| | - Lyudmila Spevak
- Hospital for Special Surgery, Weill Cornell Medical College, New York, NY, USA
| | - Sheela Shrestha
- Center of Excellence in Clinical Immunology, Children's Memorial Research Center, 2300 Children's Plaza, Box 212, Chicago, IL 60614, USA
| | - Stephen B. Doty
- Hospital for Special Surgery, Weill Cornell Medical College, New York, NY, USA
| | - Adele L. Boskey
- Hospital for Special Surgery, Weill Cornell Medical College, New York, NY, USA
| | - Lauren M. Pachman
- Center of Excellence in Clinical Immunology, Children's Memorial Research Center, 2300 Children's Plaza, Box 212, Chicago, IL 60614, USA, Department of Pediatrics, Rheumatology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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Abstract
The inflammatory response is thought to play important roles in tissue healing. The hypothesis of this study was that the inflammatory cytokine interferon (IFN)-gamma is produced endogenously following skeletal muscle injury and promotes efficient healing. We show that IFN-gamma is expressed at both mRNA and protein levels in skeletal muscle following injury, and that the time course of IFN-gamma expression correlated with the accumulation of macrophages, T-cells, and natural killer cells, as well as myoblasts, in damaged muscle. Cells of each type were isolated from injured muscle, and IFN-gamma expression was detected in each cell type. We also demonstrate that administration of an IFN-gamma receptor blocking antibody to wild-type mice impaired induction of interferon response factor-1, reduced cell proliferation, and decreased formation of regenerating fibers. IFN-gamma null mice showed similarly impaired muscle healing associated with impaired macrophage function and development of fibrosis. In vitro studies demonstrated that IFN-gamma and its receptor are expressed in the C2C12 muscle cell line, and that the IFN-gamma receptor blocking antibody reduced proliferation and fusion of these muscle cells. In summary, our results indicate that IFN-gamma promotes muscle healing, in part, by stimulating formation of new muscle fibers.
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Affiliation(s)
- Ming Cheng
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL 60612, USA
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Tjong SC, Chen TS, Huang WN, Wu WG. Structures of heparin-derived tetrasaccharide bound to cobra cardiotoxins: heparin binding at a single protein site with diverse side chain interactions. Biochemistry 2007; 46:9941-52. [PMID: 17685633 DOI: 10.1021/bi700995v] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cobra cardiotoxins (CTXs) are three-fingered polypeptides with positively charged domains that have been shown to bind to anionic ligands of snake venom citrate, glycosaminoglycans, sulfoglycosphingolipid, and nucleotide triphosphate with various biochemical effects including toxin dimerization, cell surface retention, membrane pore formation, cell internalization and blocking of enzymatic activities of kinase and ATPase. The reported anionic binding sites, however, are found to be different among different CTX homologues for potentially different CTX activities. Herein, by NMR studies of the binding of inorganic phosphate, dATP (stable form of ATP), and heparin-derived tetrasaccharide to Naja atra CTX A1, a novel CTX molecule exhibiting in vivo necrotic activity on skeletal muscle, we demonstrate that diverse ligands binding to CTXs could also occur at a single protein site with flexible side chain interactions. The flexibility of such an interaction is also illustrated by the available heparin-CTX A3 complex structures with different heparin chain lengths binding at the same site. Our results provide a likely structural explanation on how the interaction between heparan sufate and proteins depends more on the overall charge cluster organization rather than on their fine structures. We also suggest that the ligand binding site of CTX homologues can be fine-tuned by nonconserved residues near the binding pocket because of their flexible side chain interaction and dimerization ability, even for the rigid CTX molecules tightened by four disulfide bonds.
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Affiliation(s)
- Siu-Cin Tjong
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsin Chu 30043, Taiwan
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Rong H, Li Y, Lou XH, Zhang X, Gao YX, Teng MK, Niu LW. Purification, partial characterization, crystallization and preliminary X-ray diffraction of a novel cardiotoxin-like basic protein from Naja naja atra (South Anhui) venom. Acta Crystallogr Sect F Struct Biol Cryst Commun 2007; 63:130-4. [PMID: 17277458 PMCID: PMC2330133 DOI: 10.1107/s1744309107002564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Accepted: 01/17/2007] [Indexed: 11/10/2022]
Abstract
A novel cardiotoxin-like basic protein was isolated from the venom of the Chinese cobra (Naja naja atra) from the south of Anhui in China. The protein inhibits the expression of vascular endothelial growth factor and basic fibroblast growth factor in human lung cancer cell line H1299 and induces the haemolysis of rabbit erythrocytes under low-lecithin conditions. After a two-step chromatographic purification, the resultant 7 kDa protein was crystallized by the hanging-drop vapour-diffusion method at room temperature. A complete data set was collected to 2.35 A resolution using an in-house X-ray diffraction system. The crystal belongs to space group P4(1)2(1)2, with unit-cell parameters a = b = 43.2, c = 147.9 A. There are two molecules in the crystallographic asymmetric unit.
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Affiliation(s)
- Hui Rong
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230027, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230027, People’s Republic of China
| | - Yan Li
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230027, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230027, People’s Republic of China
| | - Xiao-hua Lou
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230027, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230027, People’s Republic of China
| | - Xio Zhang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230027, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230027, People’s Republic of China
| | - Yong-xiang Gao
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230027, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230027, People’s Republic of China
| | - Mai-kun Teng
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230027, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230027, People’s Republic of China
| | - Li-wen Niu
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230027, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230027, People’s Republic of China
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Kojima A, Goto K, Morioka S, Naito T, Akema T, Fujiya H, Sugiura T, Ohira Y, Beppu M, Aoki H, Yoshioka T. Heat stress facilitates the regeneration of injured skeletal muscle in rats. J Orthop Sci 2007; 12:74-82. [PMID: 17260121 DOI: 10.1007/s00776-006-1083-0] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Accepted: 09/25/2006] [Indexed: 02/09/2023]
Abstract
BACKGROUND Skeletal muscle stem cells, so-called muscle satellite cells, are responsible for the repair and the regeneration of adult skeletal muscle tissues. Heat stress can facilitate the proliferation and the differentiation of myoblasts in vitro and can enhance their proliferative potential, which may stimulate the regrowth of atrophied skeletal muscle. The purpose of this study was to investigate the effect of heat stress on the regeneration of skeletal muscle injury induced by cardiotoxin. METHODS Male Wistar rats, aged 7 weeks, were randomly divided into six groups: a nonheated control group that received a physiological saline injection, a group heat stressed before physiological saline injection, a group heat stressed after physiological saline injection, a group injected with cardiotoxin without heat stress, a group heat stressed before cardiotoxin injection, and a group heat stressed after cardiotoxin injection (25 in each group). To initiate muscle injury and regeneration, 0.5 ml of 10 microM cardiotoxin was injected into the left tibialis anterior muscle. Conscious rats in some groups were exposed to environmental heat stress (41 degrees C for 60 min) in a heat chamber 24 h before or immediately after cardiotoxin or physiological saline injection. The heating protocol in the present study causes an increase in the colonic temperature to 41 degrees C. The left tibialis anterior muscles were dissected 1, 3, 7, 14, and 28 days after injection of cardiotoxin or physiological saline. RESULTS The wet weight and water content of muscles increased 1 day after cardiotoxin injection regardless of the application of heat stress, but normalized after 7-14 days. The muscle protein content in control rats had increased 7 days after heat stress. Although the muscle protein content decreased on cardiotoxin injection, heat stress caused a significant recovery in protein level. Expression of heat shock protein 72 (HSP72) and the number of Pax7-positive nuclei decreased after cardiotoxin injection but increased on the application of heat stress in both normal control and cardiotoxin-injected groups. CONCLUSIONS Heat stress stimulated not only the proliferation of satellite cells but also protein synthesis during the regeneration of injured skeletal muscle. It is thus strongly suggested that the heating of injured skeletal muscle may facilitate recovery. There was no direct relationship between the level of HSP72 expression and muscle protein content, suggesting that HSP72 expression may not be the key signal for protein synthesis in the necrosis-regeneration process.
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Affiliation(s)
- Atsushi Kojima
- Department of Orthopaedic Surgery, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae, Kawasaki, 216-8511, Japan
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Saha A, Gomes A, Giri B, Chakravarty AK, Biswas AK, Dasgupta SC, Gomes A. Occurrence of non-protein low molecular weight cardiotoxin in Indian King Cobra (Ophiophagus hannah) Cantor 1836, venom. Indian J Exp Biol 2006; 44:279-85. [PMID: 16629369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Pathophysiology due to snakebite is a combined effect of various actions of the complex venom constituents. Importance of protein toxins in snake envenomation is well known. The present investigation reports the existence of nonprotein/nonpetide low molecular weight toxin in Indian King Cobra venom, which plays an important role in envenomation consequences in experimental animal models. A group of non-peptidic toxins (OH-NPT1) was isolated from Indian King Cobra Ophiophagus hannah by thin layer chromatography and silica gel column chromatography. UV, IR, NMR and (ESI) TOF-MS studies characterized the OH-NPT1 as a mixture of aliphatic acids having molecular weights 256, 326 and 340Da. The minimum lethal dose of OH-NPT1 was found to be 2.5 microg/20g (iv) and 4microg/20g (ip) in male albino mice. The cardiotoxic property of OH-NPT1 was established through studies on isolated guinea pig heart and auricle preparations, ECG studies in albino rat and estimation of LDH1/LDH and CPK-MB/CPK ratio in Swiss albino mice. Commercial antiserum failed to neutralize the lethality and cardiotoxicity of the toxin. However, calcium and magnesium effectively neutralized the lethal action.
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Affiliation(s)
- Archita Saha
- Laboratory of Toxinology and Experimental Pharmacodynamics, Department of Physiology, University of Calcutta, Kolkata, India
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Wang CH, Monette R, Lee SC, Morley P, Wu WG. Cobra cardiotoxin-induced cell death in fetal rat cardiomyocytes and cortical neurons: different pathway but similar cell surface target. Toxicon 2005; 46:430-40. [PMID: 16081119 DOI: 10.1016/j.toxicon.2005.06.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2005] [Revised: 06/08/2005] [Accepted: 06/10/2005] [Indexed: 02/07/2023]
Abstract
Cobra cardiotoxins (CTXs) are basic polypeptides with diverse pharmacological functions that are cytotoxic to many different cell types through both necrotic and apoptotic cell death pathways. In this comparative study of the action of CTX A3 from the Taiwan cobra (Naja atra) on fetal rat cardiomyocytes and cortical neurons, it was shown that CTX A3 induced different patterns of elevation of intracellular Ca2+ concentration ([Ca2+]i), CTX internalization, caspase-3 activity and viability. Application of an anti-sulfatide monoclonal antibody, O4 specific for 3-sulfo-galactose lipid, but not in the control experiments using anti-GM3 monoclonal antibody, reduces CTX-induced [Ca2+]i elevation, CTX internalization and toxicity. Therefore, CTX may target similar sulfo-containing cell surface receptors in both fetal rat cardiomyocytes and cortical neurons, but induce cell death through different pathways specific to each cell type.
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Affiliation(s)
- Chia-Hui Wang
- Department of Life Sciences and Institute of Bioinformatics and Structural Biology, National Tsinghua University, 30013 Hsinchu, Taiwan
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15
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Chen SE, Gerken E, Zhang Y, Zhan M, Mohan RK, Li AS, Reid MB, Li YP. Role of TNF-{alpha} signaling in regeneration of cardiotoxin-injured muscle. Am J Physiol Cell Physiol 2005; 289:C1179-87. [PMID: 16079187 PMCID: PMC3099530 DOI: 10.1152/ajpcell.00062.2005] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent data suggest a physiological role for the proinflammatory cytokine TNF-alpha in skeletal muscle regeneration. However, the underlying mechanism is not understood. In the present study, we analyzed TNF-alpha-activated signaling pathways involved in myogenesis in soleus muscle injured by cardiotoxin (CTX) in TNF-alpha receptor double-knockout mice (p55(-/-)p75(-/-)). We found that activation of p38MAPK, which is critical for myogenesis, was blocked in CTX-injured p55(-/-)p75(-/-) soleus on day 3 postinjury when myogenic differentiation was being initiated, while activation of ERK1/2 and JNK MAPK, as well as transcription factor NF-kappaB, was not reduced. Consequently, the phosphorylation of transcription factor myocyte enhancer factor-2C, which is catalyzed by p38 and crucial for the expression of muscle-specific genes, was blunted. Meanwhile, expression of p38-dependent differentiation marker myogenin and p21 were suppressed. In addition, expression of cyclin D1 was fivefold that in wild-type (WT) soleus. These results suggest that myogenic differentiation is blocked or delayed in the absence of TNF-alpha signaling. Histological studies revealed abnormalities in regenerating p55(-/-)p75(-/-) soleus. On day 5 postinjury, new myofiber formation was clearly observed in WT soleus but not in p55(-/-)p75(-/-) soleus. To the contrary, p55(-/-)p75(-/-) soleus displayed renewed inflammation and dystrophic calcification. On day 12 postinjury, the muscle architecture of WT soleus was largely restored. Yet, in p55(-/-)p75(-/-) soleus, multifocal areas of inflammation, myofiber death, and myofibers with smaller cross-sectional area were observed. Functional studies demonstrated an attenuated recovery of contractile force in injured p55(-/-)p75(-/-) soleus. These data suggest that TNF-alpha signaling plays a critical regulatory role in muscle regeneration.
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Affiliation(s)
- Shuen-Ei Chen
- Department of Medicine, Baylor College of Medicine, One Baylor Plaza 520B, Houston, TX 77030, USA
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16
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Yang SH, Lu MC, Chien CM, Tsai CH, Lu YJ, Hour TC, Lin SR. Induction of apoptosis in human leukemia K562 cells by cardiotoxin III. Life Sci 2005; 76:2513-22. [PMID: 15763081 DOI: 10.1016/j.lfs.2005.01.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2004] [Accepted: 01/03/2005] [Indexed: 11/21/2022]
Abstract
Cardiotoxin III (CTX III), a basic polypeptide with 60 amino acid residues isolated from Naja naja atra venom, has been reported to have anticancer activity. CTX III was found to inhibit the growth of K562 cells in a time-and dose-dependent manner with IC50 value of 1.7 microg/ml, and it displayed several features of apoptosis including apoptotic body formation, increase of sub G1 population, DNA fragmentation and poly (ADP-ribose) polymerase (PARP) cleavage. Investigation of the mechanism of CTXIII--induced apoptosis revealed that the treatment of K562 cells with CTX III resulted in the activation of caspase-9, caspase-3 and subsequent cleavage of its substrate PARP and that CTXIII was also associated with an early release of cytochrome c from the mitochondria. These results suggest that CTX III may induce apoptosis through a mitochondria- and caspase-dependent mechanism.
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Affiliation(s)
- Sheng-Huei Yang
- Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung, Taiwan 807, ROC
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17
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Abstract
A basic peptide with mass weight of 7.597 kDa was isolated and purified from the Naja atra venom by using the combination of ion exchange chromatography and reverse phase high performance liquid chromatography. N-terminal protein sequence determination revealed that this peptide was a weak neurotoxin. Neurotoxicity and cytotoxicity assay were performed. It was noticed that although the analysis of protein sequence did not show it was much more basic, this neurotoxin was eluted out after a cardiotoxin-like basic protein (CLBP). It was also found that, despite of low neurotoxicity, when applied to two non-neural cell lines including K562 cells and K1735-M2 cells, this weak neurotoxin exhibits synergic effects with cardiotoxins, which is firstly reported. It was presumed that the synergic effect might be due to the presence of their common characteristic tertiary structure, three-finger structure. This fact might bring us some new sights about the functions of the un-lethal components in the complex venom system and may help us to understand how the venom really works as an integrative system.
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Affiliation(s)
- Heng Zhou
- Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, China
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18
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Abstract
The review explains why the myotoxic phospholipases A2 and cardiotoxins are such important tools in the study of the regeneration and maturation of mammalian skeletal muscle. The role of satellite cells as precursors of cell-based regeneration is discussed and recent controversies on the origin of myogenic cells involved in the regeneration of mature skeletal muscle are addressed. This is followed by discussions of sarcomere reconstruction, myosin and sarcoplasmic reticulum ATPase expression, the electrophysiological properties of regenerating muscle, and the reconstruction of the neuromuscular junction. The emphasis throughout is on the plastic changes of major structural and functional proteins that occur during regeneration, and on other influences that determine the final outcome of regenerative activity such as innervation, thyroid status, mechanical work and the functional integrity of the microcirculation. The review closes with a discussion of some of the factors--such as active regeneration--that influence the success of gene-based therapies applied to inherited muscle disease.
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Affiliation(s)
- J B Harris
- School of Neurology, Neurobiology and Psychiatry, Faculty of Medical Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, UK.
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19
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Abstract
Cardiotoxin-III (CTX-III), a major cardiotoxin isolated from the venom of the Taiwan cobra (Naja naja atra), is a highly basic, hydrophobic, toxic protein, which can induce lysis of mononuclear cells by an unknown mechanism. This study was undertaken to investigate the effects of CTX-III on untreated and PHA-activated peripheral blood mononuclear cells (PBMCs) in vitro. The results show that treatment of PHA-activated lymphocytes with CTX-III (10 microg/ml) induced apoptosis and depletion of the CD8(+) population. In both untreated and PHA-treated lymphocytes, interferon-gamma production was dramatically reduced and interleukin-2 (IL-2) production was moderately reduced by CTX-III treatment. In PHA-activated lymphocytes, CD4 expression was increased, whereas CD8 and IL-2R beta chain (CD25) expression were decreased. In contrast, CTX-III had no effect on the viability of PHA-activated monocytes but significantly enhanced their tumor necrosis factor-alpha production. These results show that CTX-III selectively enhanced activation-induced apoptosis in CD8(+) T cells. CTX-III was found to bind to the cell membrane of PHA-stimulated PBMCs, and three CTX-III-binding proteins, with molecular weights of 92, 77, and 68 kDa, were identified. We therefore propose that CTX-III interacts with one or more cell surface proteins and initiates a signal pathway causing functional changes. These findings provide an insight into the immunomodulatory properties of CTX-III and suggest a novel method for the selective induction of apoptosis in CD8(+) T lymphocytes.
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Affiliation(s)
- Shu-Hui Su
- Department of Cosmetic Science, Chung Hwa College of Medical Technology, Tainan 717 Taiwan
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20
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Hirata A, Masuda S, Tamura T, Kai K, Ojima K, Fukase A, Motoyoshi K, Kamakura K, Miyagoe-Suzuki Y, Takeda S. Expression profiling of cytokines and related genes in regenerating skeletal muscle after cardiotoxin injection: a role for osteopontin. Am J Pathol 2003; 163:203-15. [PMID: 12819025 PMCID: PMC1868192 DOI: 10.1016/s0002-9440(10)63644-9] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
To examine the roles of cytokines in muscle regeneration, we injected cardiotoxin into mouse tibialis anterior muscle and examined the expression profiles of cytokines and related genes in the regeneration process. Expression of 40, 64, and 7 genes among 522 genes spotted on a cytokine expression array were increased more than fivefold at 48 hours, 96 hours, and 7 days after toxin injection, respectively, when compared with those of the control muscle. Especially the levels of mRNA for chemokines and chemokine receptors, many of which are potent regulators of macrophages, were highly elevated 48 hours after injury. The expression of osteopontin (OPN), a versatile regulator of inflammation and tissue repair, was up-regulated more than 118-fold in regenerating muscle at 48 hours after injury. Northern blotting confirmed that the expression of OPN was highest at 48 hours after cardiotoxin injection and declined sharply thereafter. Immunohistochemistry showed that OPN was detected both in the cytoplasm of macrophages and in necrotic muscle infiltrated with macrophages. Our studies suggest OPN may serve as an adhesion molecule that promotes macrophage binding to necrotic fibers and may be an important mediator in the early phase of muscle regeneration.
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Affiliation(s)
- Akira Hirata
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
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Hoshino S, Ohkoshi N, Ishii A, Shoji S. The expression of dystrophin, alpha-sarcoglycan, and beta-dystroglycan during skeletal muscle regeneration: immunohistochemical and western blot studies. Acta Histochem 2002; 104:139-47. [PMID: 12086334 DOI: 10.1078/0065-1281-00620] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We evaluated re-expression of dystrophin, alpha-sarcoglycan and beta-dystroglycan in regenerating skeletal muscles of rats after cardiotoxin-induced myonecrosis in order to understand the dynamic behaviour of these proteins during the regeneration process. Immunohistochemical staining of these proteins almost disappeared in the sarcolemma of necrotic fibers on the 1st day, and was obscured due to non-specific staining on the 3rd day. Dystrophin was labeled faintly at the sarcolemma of regenerating muscle fibers on the 5th day. From the 5th day to the 10th day, levels of immunostaining of dystrophin increased. After the 14th day, dystrophin was stained conspicuously. alpha-Sarcoglycan was labeled weakly at the sarcolemma of small regenerating muscle fibers on the 5th day and was labeled conspicuously after the 7th day. beta-Dystroglycan was labeled moderately at the sarcolemma of regenerating muscle fibers on the 5th day and was labeled conspicuously after the 7th day. In western blot analysis, beta-dystroglycan persisted throughout the entire cycle of myonecrosis and regeneration, and re-expression of alpha-sarcoglycan progressed faster than that of dystrophin. We speculate that regeneration advances from the basement membrane side to the subsarcolemmal side, and that proteins at the basement membrane side resist disruption and have a high capacity for regeneration.
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Affiliation(s)
- Sachiko Hoshino
- Department of Neurology, Institute of Clinical Medicine, University of Tsukuba, Japan
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Hosaka Y, Yokota T, Miyagoe-Suzuki Y, Yuasa K, Imamura M, Matsuda R, Ikemoto T, Kameya S, Takeda S. Alpha1-syntrophin-deficient skeletal muscle exhibits hypertrophy and aberrant formation of neuromuscular junctions during regeneration. J Cell Biol 2002; 158:1097-107. [PMID: 12221071 PMCID: PMC2173222 DOI: 10.1083/jcb.200204076] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Alpha1-syntrophin is a member of the family of dystrophin-associated proteins; it has been shown to recruit neuronal nitric oxide synthase and the water channel aquaporin-4 to the sarcolemma by its PSD-95/SAP-90, Discs-large, ZO-1 homologous domain. To examine the role of alpha1-syntrophin in muscle regeneration, we injected cardiotoxin into the tibialis anterior muscles of alpha1-syntrophin-null (alpha1syn-/-) mice. After the treatment, alpha1syn-/- muscles displayed remarkable hypertrophy and extensive fiber splitting compared with wild-type regenerating muscles, although the untreated muscles of the mutant mice showed no gross histological change. In the hypertrophied muscles of the mutant mice, the level of insulin-like growth factor-1 transcripts was highly elevated. Interestingly, in an early stage of the regeneration process, alpha1syn-/- mice showed remarkably deranged neuromuscular junctions (NMJs), accompanied by impaired ability to exercise. The contractile forces were reduced in alpha1syn-/- regenerating muscles. Our results suggest that the lack of alpha1-syntrophin might be responsible in part for the muscle hypertrophy, abnormal synapse formation at NMJs, and reduced force generation during regeneration of dystrophin-deficient muscle, all of which are typically observed in the early stages of Duchenne muscular dystrophy patients.
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Affiliation(s)
- Yukio Hosaka
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1 Ogawa-higashi, Kodaira 187-8502, Tokyo, Japan
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Abstract
The effects of snake venom on the cholinergic system have been well-studied; however, no similar studies have been performed on the adrenergic system. Adrenomedullary cells secrete catecholamine (CA) on stimulation; thus they are an ideal system to study the effect of snake venoms on CA secretion or inhibition. Snake venoms from different Families and Genera were investigated. All snake venoms investigated, caused CA efflux. CA can be released when cytolysis takes place; so in order to assert CA efflux was not due to cytolysis, venoms were added after the cells were treated with KCl. Most venom, with the exception of sea snake (Hydrophiidae) venom, was found to induce CA release due to cytolysis. The effects of purified components such as phospholipase A2, neurotoxin I, and cardiotoxin were also investigated. Neurotoxin I caused neither cytolysis nor CA efflux. Cardiotoxin caused marked cytolysis, but with slightly less damaging effects than that of cobra venom. Some ion channel blockers prevented cytolysis induced by cardiotoxin. The CA efflux induced by cardiotoxin may be mediated through Ca2+ channels because the efflux could be completely depressed by a Ca2+ channel blocker (1 mM CdCl2).
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Affiliation(s)
- Yuang Zhang
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins 80523, USA
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24
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Affiliation(s)
- Raymond F Castro
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
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25
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Abstract
Six cardiotoxins (CTXs) and one cardiotoxin-like basic protein (CLBP) from Naja naja atra (Taiwan cobra) venom were separated by a SP-Sephadex C-25 column. CTXn and CTXI were well separated by eluting with ammonium acetate buffer, and the separation of CLBP from CTXIV and CTXV mixtures was achieved using sodium phosphate buffer. These findings suggest a differential interaction of CTXs with the chromatographic matrix using different buffer systems. Chemical modification studies on cationic residues of CTXI suggested that there was no single lysine or arginine residue exclusively responsible for its biological activity. Moreover, it was found that the cytotoxicity and hemolytic sites of CTXI could be dissociated by chemical modifications. It suggests the potentiality for preparing toxin derivatives in which a specific activity is retained.
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Affiliation(s)
- Shinne-Ren Lin
- School of Chemistry, Kaohsiung Medical University, Taiwan, ROC.
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Stanchi NO, Arias D, Bartolucci E, Martino PE, Gimeno EJ, Diez RA, Costa LA. One-month safety study of intraperitoneal VRCTC-310-Onco (crotoxin + cardiotoxin) in rats. Arzneimittelforschung 2000; 50:862-6. [PMID: 11050707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
To evaluate the toxicity of VRCTC-310-Onco (Crotalus durissus terrificus crotoxin + cardiotoxin from Naja naja atra), 10 Sprague-Dawley rats were implanted with intraperitoneal slow-release devices and subjected to treatment with 0.5 microgram/g body weight/d for 14 days. Biochemical evidence at days 7 and 14 showed blood, muscular, renal and metabolic disturbance, mostly reversed by day 28. No significant changes were found in necropsy. The limited toxicity of i.p. VRCTC-310-Onco in rats deserves further study.
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Affiliation(s)
- N O Stanchi
- Cátedra de Microbiologia, Facultad de Ciencias Veterinarias (UNLP), Argentina
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Garry DJ, Meeson A, Elterman J, Zhao Y, Yang P, Bassel-Duby R, Williams RS. Myogenic stem cell function is impaired in mice lacking the forkhead/winged helix protein MNF. Proc Natl Acad Sci U S A 2000; 97:5416-21. [PMID: 10792059 PMCID: PMC25843 DOI: 10.1073/pnas.100501197] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Myocyte nuclear factor (MNF) is a winged helix transcription factor that is expressed selectively in myogenic stem cells (satellite cells) of adult animals. Using a gene knockout strategy to generate a functional null allele at the Mnf locus, we observed that mice lacking MNF are viable, but severely runted. Skeletal muscles of Mnf-/- animals are atrophic, and satellite cell function is impaired. Muscle regeneration after injury is delayed and incomplete, and the normal timing of expression of cell cycle regulators and myogenic determination genes is dysregulated. Mnf mutant mice were intercrossed with mdx mice that lack dystrophin and exhibit only a subtle myopathic phenotype. In contrast, mdx mice that also lack MNF die in the first few weeks of life with a severe myopathy. Haploinsufficiency at the Mnf locus (Mnf+/-) also exacerbates the mdx phenotype to more closely resemble Duchenne's muscular dystrophy in humans. We conclude that MNF acts to regulate genes that coordinate the proliferation and differentiation of myogenic stem cells after muscle injury. Animals deficient in MNF may prove useful for evaluation of potential therapeutic interventions to promote muscle regeneration for patients having Duchenne's muscular dystrophy.
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Affiliation(s)
- D J Garry
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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Jayaraman G, Kumar TK, Tsai CC, Srisailam S, Chou SH, Ho CL, Yu C. Elucidation of the solution structure of cardiotoxin analogue V from the Taiwan cobra (Naja naja atra)--identification of structural features important for the lethal action of snake venom cardiotoxins. Protein Sci 2000; 9:637-46. [PMID: 10794406 PMCID: PMC2144616 DOI: 10.1110/ps.9.4.637] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The aim of the present study is to understand the structural features responsible for the lethal activity of snake venom cardiotoxins. Comparison of the lethal potency of the five cardiotoxin isoforms isolated from the venom of Taiwan cobra (Naja naja atra) reveals that the lethal potency of CTX I and CTX V are about twice of that exhibited by CTX II, CTX III, and CTX IV. In the present study, the solution structure of CTX V has been determined at high resolution using multidimensional proton NMR spectroscopy and dynamical simulated annealing techniques. Comparison of the high resolution solution structures of CTX V with that of CTX IV reveals that the secondary structural elements in both the toxin isoforms consist of a triple and double-stranded antiparallel beta-sheet domains. Critical examination of the three-dimensional structure of CTX V shows that the residues at the tip of Loop III form a distinct "finger-shaped" projection comprising of nonpolar residues. The occurrence of the nonpolar "finger-shaped" projection leads to the formation of a prominent cleft between the residues located at the tip of Loops II and III. Interestingly, the occurrence of a backbone hydrogen bonding (Val27CO to Leu48NH) in CTX IV is found to distort the "finger-shaped" projection and consequently diminish the cleft formation at the tip of Loops II and III. Comparison of the solution structures and lethal potencies of other cardiotoxin isoforms isolated from the Taiwan cobra (Naja naja atra) venom shows that a strong correlation exists between the lethal potency and occurrence of the nonpolar "finger-shaped" projection at the tip of Loop III. Critical analysis of the structures of the various CTX isoforms from the Taiwan cobra suggest that the degree of exposure of the cationic charge (to the solvent) contributed by the invariant lysine residue at position 44 on the convex side of the CTX molecules could be another crucial factor governing their lethal potency.
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Affiliation(s)
- G Jayaraman
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
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29
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Bigard AX, Mateo P, Sanchez H, Serrurier B, Ventura-Clapier R. Lack of coordinated changes in metabolic enzymes and myosin heavy chain isoforms in regenerated muscles of trained rats. J Muscle Res Cell Motil 2000; 21:269-78. [PMID: 10952174 DOI: 10.1023/a:1005680921792] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We investigated training-induced changes in biochemical properties and myosin heavy chain (MHC) composition of regenerated (cardiotoxin-injected) plantaris muscles (PLA) in rats either maintained sedentary (S, n = 9) or endurance trained on a treadmill over a 8-week period (T, n = 7). Both endurance training and regeneration altered the pattern of fast MHC expression. An analysis of the two-way interaction between training and regeneration showed that the relative content of type IIa MHC was affected (P < 0.05). The 140% increase in type IIa MHC observed in regenerated PLA from T rats compared with nontreated muscle of S rats, exceeded the 102% increase resulting from the combination of regeneration alone (26%) and training alone (61%). A similar interaction between training and regeneration was shown for the percentage of fibres expressing either type IIa or type lIb MHC (P < 0.05). In contrast, a significant increase in the citrate synthase (CS) activity was shown in PLA as a result of endurance training, without specific effect of regeneration. Furthermore, training-induced changes in CK and LDH isoenzyme distribution occurred to a similar extent in regenerated and non-treated PLA muscles, and thus did not follow the changes in MHC isoforms. An increase in the mitochondrial CK isozyme activity (mi-CK) was shown in both non-treated and previously degenerated PLA muscles (123 and 117%, P < 0.01, respectively), without specific effect of regeneration. The ratio of mi-CK to CS activity, an estimate of the mitochondrial specific activity of mi-CK was significantly increased by training (P < 0.02) and decreased by regeneration (P < 0.05). Taken together, these data suggest that while training and regeneration have cumulative effects on the pattern of fast MHC expression, the training-induced changes in the energy metabolism shown in mature non-treated myofibres are similar to those observed in regenerated fibres.
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Affiliation(s)
- A X Bigard
- Unité de Bioénergétique et Environnement, Centre de Recherches du Service de Santé des Armées, La Tronche, France.
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30
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Cooper RN, Tajbakhsh S, Mouly V, Cossu G, Buckingham M, Butler-Browne GS. In vivo satellite cell activation via Myf5 and MyoD in regenerating mouse skeletal muscle. J Cell Sci 1999; 112 ( Pt 17):2895-901. [PMID: 10444384 DOI: 10.1242/jcs.112.17.2895] [Citation(s) in RCA: 277] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Regeneration of adult skeletal muscle is an asynchronous process requiring the activation, proliferation and fusion of satellite cells, to form new muscle fibres. This study was designed to determine the pattern of expression in vivo of the two myogenic regulatory factors, Myf5 and MyoD during this process. Cardiotoxin was used to induce regeneration in the gastrocnemius and soleus muscles of heterozygous Myf5-nlacZ mice, and the muscles were assayed for the presence of (beta)-galactosidase (Myf5) and MyoD. Adult satellite cells identified by M-cadherin labelling, when activated, initially express either MyoD or Myf5 or both myogenic factors. Subsequently all proliferating myoblasts express MyoD and part of the population is (beta)-galactosidase (Myf5) positive. Furthermore, we demonstrate that activated satellite cells, which express either Myf5 or MyoD, do not accumulate selectively on fast or slow muscle fibres.
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Affiliation(s)
- R N Cooper
- CNRS URA 2115, Blvd de l'hôpital, France
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31
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Ho KH, Kwan CY, Huang SJ, Bourreau JP. Dual effect of cobra cardiotoxin on vascular smooth muscle and endothelium. Zhongguo Yao Li Xue Bao 1998; 19:197-202. [PMID: 10375725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
AIM To assess the cytotoxic effects of cobra cardiotoxin (CTX) on rat aorta. METHODS Measure of contractility of aortic rings with or without endothelium. RESULTS In endothelium-intact rings, CTX 10 mumol.L-1 induced a transient relaxation followed by a sustained contraction. Removal of the endothelium or pre-incubation of the rings with NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) abolished the transient relaxation but did not affect the magnitude of the contractile response induced by CTX. CTX itself induced contraction of vascular smooth muscle but also reduced contractions induced by phenylephrine (PhE) or KCl stimulation in a concentration-dependent manner. Contraction induced by CTX was dependent on the external Ca2+ concentration. Maximal contractile response to CTX was obtained in medium containing Ca2+ 1 mmol.L-1. This response decreased with higher Ca2+ concentration and disappeared when Ca2+ 7 mmol.L-1, organic and inorganic calcium channel blockers were present in the external solution before CTX addition. In preparations with the endothelium intact and incubated with CTX, relaxation by acetylcholine (ACh) stimulation of the tension induced by PhE was decreased. Endothelium-dependent relaxation to ACh was preserved when Ca2+ 5 mmol.L-1 was added to the medium prior to CTX. CONCLUSION CTX first triggers the release of NO from the endothelium which results in muscle relaxation, and then causes smooth muscle contraction, Ca2+ and Ca2+ channel blockers prevented the effect of CTX.
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Affiliation(s)
- K H Ho
- Department of Physiology, University of Hong Kong, China
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32
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Abstract
Snake cardiotoxins are highly basic (pI > 10) small molecular weight (approximately 6.5 kDa), all beta-sheet proteins. They exhibit a broad spectrum of interesting biological activities. The secondary structural elements in these toxins include antiparallel double and triple stranded beta-sheets. The three dimensional structures of these toxins reveal an unique asymmetric distribution of the hydrophobic and hydrophilic amino acids. The 3D structures of closely related snake venom toxins such as neurotoxins and cardiotoxin-like basic proteins (CLBP) fail to show similar pattern(s) in the distribution of polar and nonpolar residues. Recently, many novel biological activities have been reported for cardiotoxins. However, to-date, there is no clear structure-function correlation(s) available for snake venom cardiotoxins. The aim of this comprehensive review is to summarize and critically evaluate the progress in research on the structure, dynamics, function and folding aspects of snake venom cardiotoxins.
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Affiliation(s)
- T K Kumar
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
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33
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Ou YJ, Leung YM, Huang SJ, Kwan CY. Dual effects of extracellular Ca2+ on cardiotoxin-induced cytotoxicity and cytosolic Ca2+ changes in cultured single cells of rabbit aortic endothelium. Biochim Biophys Acta 1997; 1330:29-38. [PMID: 9375810 DOI: 10.1016/s0005-2736(97)00136-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The effects of extracellular Ca2+ on cytotoxicity induced by cardiotoxin (CTX), isolated from Chinese cobra venom, were investigated in cultured rabbit aortic endothelial cells (RAECs). In Hank's buffered saline solution (HBSS) containing 1.2 mM Ca2+, CTX (1-30 microM) caused cell necrosis and cell death in a concentration-dependent manner, as determined by trypan blue exclusion test performed after a 20-min CTX treatment. The concentration of CTX that caused 50% cell death was about 6.5 microM. CTX (10 microM)-induced RAEC damage was also evident but less prominent in Ca2+-free medium and almost completely prevented in medium containing 7-10 mM Ca2+. Therefore, Ca2+ appears to provoke CTX-induced injury at physiological concentrations, but protects against it at high concentrations. The protection of RAECs from CTX-induced injury could also be achieved by high concentrations of Ni2+ and Mg2+. Using the fura-2 fluorescence technique to measure the cytosolic free Ca2+ concentration ([Ca2+]i) of single RAEC, it was shown that in 1.2 mM Ca2+-containing HBSS, treatment of RAECs with 10 microM CTX for 7-35 min resulted in a tremendous and irreversible [Ca2+]i elevation, suggestive of cell membrane damage and extracellular Ca2+ entry. Ni2+ could also enter the cytosol of these damaged RAECs. However, there was no [Ca2+]i elevation or Ni2+ entry in RAECs that were preincubated in HBSS containing 7 mM Ca2+ or Ni2+ before CTX exposure. In RAECs protected with 7 mM Ca2+, the intracellular Ca2+ signals triggered by 100 microM extracellular ATP or 10 microM bradykinin in CTX-treated groups were similar to those in the untreated control groups. Taken together, the results indicate that high extracellular Ca2+ concentrations protected RAECs from CTX-induced injury, and preserved the ability of CTX-treated RAECs to generate Ca2+ signals in response to physiological stimuli.
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Affiliation(s)
- Y J Ou
- Department of Physiology, Faculty of Medicine, The University of Hong Kong, China
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34
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Abstract
The purpose of the present study is the investigation of the structure and dynamics of biological membranes using solid-state nuclear magnetic resonance (NMR) spectroscopy. Two approaches are used in our laboratory. The first involves the measurement of high-resolution 13C and 1H spectra obtained by the magic angle spinning (MAS) technique while the second approach involves the measurement of 31P and 2H powder spectra in static samples. This paper will present some recent results obtained by high-resolution solid-state 1H NMR on the conformation of gramicidin A incorporated in a phosphatidylcholine bilayers. More specifically, we were able to observe changes in the gramicidin spectra as a function of the cosolubilization solvent initially used to prepare the samples. The interaction between lipid bilayers and an anticancer drug derived from chloroethylurea was also investigated using proton NMR spectroscopy. Finally, we have studied the interaction between cardiotoxin, a toxic protein extracted from snake venom, and negatively charged lipid bilayers using 31P solid-state NMR spectroscopy.
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Affiliation(s)
- M Auger
- Département de Chimie, CERSIM, Université Laval, Québec, Canada.
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35
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Abstract
Several studies have suggested that along the concave surface of cobra venom cytotoxins, a hydrophobic region flanked by positively charged amino acid side-chains, as well as by tyrosine and/or serine/threonine, allows these toxins to depolarize muscle or cause cytolysis. Comparison of biological activities among structurally homologous toxins, however, has revealed significant functional diversity. The objective of the present study was to examine several toxins purified from different cobra venoms with regard to their ability to bind to and kill human T-lymphocytes and rat heart cell myoblasts. The activities observed were then correlated with differences in amino acid residues which occur in restricted regions of the toxins. The absence of an aromatic residue at position 11 (Loop 1) resulted in a lower cytolytic response at every concentration tested. A simple inversion of two residues in the amino acid sequence of toxin Loop 3 selectively impaired heart cell binding and cytolysis, but had no effect on T-cells. Loss of a positively charged residue in the tip of Loop 2 minimally affected binding but significantly reduced cytolysis. Replacement of valine at positions 27 and 32, along with the introduction of a negative charge at the tip of Loop 2, interfered with binding to either cell type and caused a reduction in cytolysis. The results of this study suggest that no one loop or region is solely responsible for the toxin's biological activity. However, because the binding and cytolytic sites within these toxins are distinct, it may become possible to develop toxin derivatives in which only selected activities are enhanced.
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Affiliation(s)
- R Stevens-Truss
- Department of Medicinal and Biological Chemistry, College of Pharmacy, University of Toledo, OH 43606, USA
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36
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Wu CY, Chen WC, Ho CL, Chen ST, Wang KT. The role of the N-terminal leucine residue in snake venom cardiotoxin II (Naja naja atra). Biochem Biophys Res Commun 1997; 233:713-6. [PMID: 9168920 DOI: 10.1006/bbrc.1997.6503] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The N-terminal leucine residue of snake venom cardiotoxin II (CTX II) (Naja naja atra) was systematically replaced with D-leucine (CTXII-L1-D-L), glycine (CTXII-L1G) or deleted [CTXII-(2-60)] to study the role of leucine residue in CTX II molecule. CTX II, CTXL1-D-L, CTXL1G and CTX(2-60) were produced by chemical synthesis method and purified by high performance liquid chromatography. Owing to folding problem in CTXII-(2-60), only CTX II, CTXII-L1-D-L and CTXII-L1G were produced in a pure form and characterized by amino acid analysis, mass spectrometry and peptide mapping. In the structural aspect, changing the Leu-1 by D-Leu or Gly causes a drastic alteration in the whole CTX II structure as detected by circular dichroism, 1-anilino-naphthalene-8-sulfonate (ANS) fluorescence assay. In the functional aspect, both CTXII-L1-D-L and CTXII-L1G are still retained substantial biological activity of CTX II. Therefore, the results indicate that both the chirality and the side-chain of the N-terminal leucine residue of CTX II are important elements in maintaining the whole CTX II structure. In addition, this study is the first report in elucidating the reason why the first N-terminal residue of most CTXs (90.3%) is leucine residue.
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Affiliation(s)
- C Y Wu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan, Republic of China
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37
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Abstract
Myonecrosis induced in vivo by cardiotoxin, melittin, and Asp49 and Lys49 phospholipase A2 (PLA2) myotoxins involves rapid lysis of the sarcolemma, myofibril clumping, and hypercontraction of sarcomeres. In contrast, skeletal muscle necrosis induced by crotamine and myotoxin a is much slower, consisting of mitochondrial and sarcoplasmic reticulum swelling, myofibril degeneration, and lack of sarcolemma or transverse tubule damage. The mechanisms contributing to the myonecrosis induced by these peptides were evaluated. Two cardiotoxins and two Lys49 PLA2 myotoxins lysed primary cultures of human skeletal muscle within 24 hr at a concentration of 0.25 microM, while melittin, crotamine, and myotoxin a, and an Asp49 PLA2 myotoxin were non-cytolytic at concentrations up to 5.0 microM, suggesting that cytolysis is not a good measure of myotoxicity. Crotamine and the Lys49 PLA2 myotoxin altered Ca2+ ion flux in human heavy sarcoplasmic reticulum by opening the ryanocine receptor. Whole-cell patch-clamp studies demonstrated that administrating crotamine intracellularly increased Na+ currents. Free fatty acids, liberated by activation of tissue phospholipase C or by the PLA2 activity of the myotoxins, were monitored for crotamine, myotoxin a and a Lys49 PLA2 myotoxin in cell cultures in which the lipids had been radiolabeled. Only the Lys49 myotoxin produced significant amounts of fatty acid in cell cultures, supporting a potential role for fatty acid production only in the mechanism of sarcolemma-destroying myotoxins. These findings, coupled with those in the literature, support a hypothesis in which the myotoxins and/or products of lipase activity (e.g. fatty acids) are acting at a site existing on both the Na+ channel and a protein involved in Ca2+ release and probably serving a modulatory function for ion regulation. Based on the similarities in mechanisms between the toxins and fatty acids, the most likely site would be a fatty acid binding site on the protein (either similar to that on fatty acid binding proteins, or an acylated cysteine residue) or in the membrane.
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Affiliation(s)
- J E Fletcher
- Department of Anesthesiology, Medical College of Pennsylvania, Philadelphia 19102-1192, USA
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38
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Abstract
The effects of direct lytic factor (DLF) on respiratory ventilation, gas exchange as well as hemodynamics were studied in anesthetized dogs. After an intravenous DLF dose of 1 mg/kg, the initial manifestation of intoxication was observed as follows: (1) Increase in airway impedance characterized by slowed air flow rate and increased negative transpulmonary pressure. (2) Decrease in dynamic compliance. (3) Progressive increase in venoarterial shunt (Qs/Qt) and decrease in PaO2, (4) Elevation of pulmonary artery blood pressure and fall of mean systemic blood pressure and maximal left ventricular pressure. Above actions reached the peak values at 15 min and thereafter all respiratory functional parameters, except Qs/Qt and hypoxemia, returned gradually to approach the normal levels at 50 min. The tidal volume, PaCO2 and LVEDP remained unchanged until another DLF dose of 1.5 mg/kg was given. After a second dose of DLF (total 2.5 mg/kg), the respiratory functions and the cardiac performance deteriorated as follows: (1) Further increase in Qs/Qt and hypoxemia. (2) Appearance of hypercapnea and acidosis. (3) Fall of dP/dtmax and elevation of LVEDP, widening of QRS complex of ECG. (4) Blood pressure run a downhill course. From above experimental evidence, we came to the conclusion that as well as the basic cardiotoxicity, respiratory toxicity of DLF must be considered as the primary, because of broad spectrum of action of DLF and early effect on respiratory function.
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Affiliation(s)
- S J Huang
- Pharmacology Department, Sun Yat-sen University of Medical Sciences, Guangzhou, China
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39
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DeTolla LJ, Stump KC, Russell R, Viskatis LJ, Vidal JG, Newman RA, Etcheverry MA. Toxicity of the novel animal-derived anticancer agent, VRCTC-310: acute and subchronic studies in beagle dogs. Toxicology 1995; 99:31-46. [PMID: 7762000 DOI: 10.1016/0300-483x(94)02995-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Acute and subchronic toxicities of VRCTC-310, a combination product of crotoxin (CT) and cardiotoxin (CD), which has shown antitumor activity in vivo, have been studied in Beagle dogs. Single i.m. doses of 0.25, 0.5 and 1.0 mg/kg resulted in dose-dependent local muscular toxicity consisting of myofiber atrophy, interstitial edema and macrophage infiltration. Also, AST, ALT and LDH levels increased on day 2, returning to normal values on days 6-8. Local lesions were absent after recovery on day 45. At 2.0 mg/kg, signs of neurotoxicity (ataxia) appeared, in addition to vomitus, salivation, hematuria and myotoxicity in tongue and diaphragm on day 8. Local lesions healed with fibrosis at the site of injection on day 45. Administration of fixed (0.025 and 0.05 mg/kg) or escalating (0.025-0.1 mg/kg) daily doses for 30 days also produced local muscular damage, which was absent at day 75. The increases in AST, ALT and LDH serum activities on days 2-4 were independent of dosing schedule and sharply decreased on day 8, despite continuation of treatment. An escalating dose schedule of 0.025-2.0 mg/kg showed local muscle damage at the site of injection on day 31, however, there were no lesions of myotoxicity in the tongue or diaphragm and no clinical signs of neurotoxicity were observed. Animals tolerated the subchronic treatment better than the acute. The resolution of serum enzymes to normal values during treatment may be attributed to a decrease of sensitivity to VRCTC-310-mediated myotoxic effects.
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Affiliation(s)
- L J DeTolla
- Department of Medicine (Infectious Diseases), School of Medicine, University of Maryland, Baltimore, USA
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40
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Chien KY, Chiang CM, Hseu YC, Vyas AA, Rule GS, Wu W. Two distinct types of cardiotoxin as revealed by the structure and activity relationship of their interaction with zwitterionic phospholipid dispersions. J Biol Chem 1994; 269:14473-83. [PMID: 8182052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Cardiotoxins (CTXs) are a group of homologous proteins found in cobra snake venom and consist of 60-62 amino acid residues. Although CTXs are known to consist of three extended beta-sheet loops similar to neurotoxins, the target and interaction of CTXs with membranes unlike those of neurotoxins are not well understood. Herein, we report comparative studies of 10 CTXs purified from Taiwan cobra (Naja naja atra) and Mozambique spitting cobra (Naja mossambica mossambica) snake venoms with respect to their interactions with zwitterionic phospholipids. Based on the CTX-induced mixing of sphingomyelin vesicles and the binding of CTX to lysophosphatidylcholine micelles, two distinct types of CTX, i.e. P- and S-type CTX, are identified. P-type CTXs are characterized by the presence of Pro-31 within a putative phospholipid binding site near the tip of loop 2; whereas S-type CTXs are characterized by the presence of Ser-29 within the same but more hydrophilic region. Although binding of all CTXs to phospholipid membranes involves a phospholipid binding site at loop 1, P-type CTXs exhibit higher fusion and binding activity than S-type CTXs, presumably due to the additional phospholipid binding site at loop 2. The binding modes of P- and S-type CTX are thus different. Analysis of the primary structures of 46 CTXs from the genus Naja indicates that these two types of CTXs exist in all species examined. Reasonable structure/activity correlation can be detected for the effects of CTXs on muscle and red blood cells, although notable exceptions are also found. S-type CTXs are generally found to exhibit higher muscle cell depolarization activity, whereas P-type CTXs are found to possess a higher hemolytic activity. Thus the mechanism of action of CTXs seems to involve CTX-membrane interactions and depends on the type of the cell membrane and CTX molecules under study. The two lipid binding sites in P-type CTXs and one lipid binding site in S-type CTXs show large variation in their amino acid residues, but they do display some common distribution of residue type. Analogous to the signal sequences for protein import, these regions are characterized by the coexistence of an exposed hydrophobic surface flanked on either side by a cationic residue. A hypothesis is proposed to explain the general cytotoxic and specific cardiotoxic effect of CTXs based on the two CTX subtypes in snake venom.
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Affiliation(s)
- K Y Chien
- Institute of Life Sciences, National Tsing Hua University, Hsinchu, Taiwan
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41
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Zheng B, Chambers TC, Raynor RL, Markham PN, Gebel HM, Vogler WR, Kuo JF. Human leukemia K562 cell mutant (K562/OA200) selected for resistance to okadaic acid (protein phosphatase inhibitor) lacks protein kinase C-epsilon, exhibits multidrug resistance phenotype, and expresses drug pump P-glycoprotein. J Biol Chem 1994; 269:12332-8. [PMID: 7512966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
A human leukemia K562 cell mutant (K562/OA200) selected for resistance to okadaic acid (OA), an inhibitor of protein phosphatases 1 and 2A (PP1/PP2A), has been established. In wild type cells, the cytotoxicity of OA was associated with mitotic arrest and concentration- and time-dependent DNA fragmentation, a hallmark of apoptosis. The mutant was 100-fold more resistant to OA in terms of effects on these parameters. Although the synthesis of several proteins was altered, enzyme assay and immunoblot analysis indicated that the levels of PP1 and PP2A were unchanged in the mutant. Protein kinase C (PKC) assays and immunoblot analysis of calcium-dependent (cPKC) and calcium-independent (nPKC) isoforms revealed that nPKC-epsilon was strikingly absent in the mutant, which otherwise expressed in comparable amounts all other isotypes (cPKC-alpha, cPKC-beta, and nPKC-zeta) also present in the wild type. Northern blot analysis confirmed an absence of PKC-epsilon mRNA in the mutant cells. The OA200 cells were cross-resistant not only to another PP1/PP2A inhibitor, calyculin A, but also to structurally unrelated anticancer drugs (such as vinblastine and taxol) and furthermore, overexpressed the verapamil-sensitive drug pump P-glycoprotein at both the protein and mRNA levels. The mutant, however, was not cross-resistant to several PKC inhibitors tested including cardiotoxin, mastoparan, staurosporine, and an alkylphospholipid. Cardiotoxin, at a subtoxic concentration, enhanced by 6-fold vinblastine cytotoxicity in OA200 cells. These findings indicate that the multidrug resistance phenotype can be induced by cytotoxic agents other than conventional anticancer drugs, show that the development of multidrug resistance is not necessarily associated with increased cPKC activity, and identify certain PKC inhibitors that have potential as resistance modulators.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1
- Antineoplastic Agents/toxicity
- Blotting, Western
- Carcinogens/toxicity
- Carrier Proteins/biosynthesis
- Cell Division/drug effects
- Clone Cells
- Cobra Cardiotoxin Proteins/toxicity
- Dose-Response Relationship, Drug
- Drug Resistance/physiology
- Ethers, Cyclic/toxicity
- Humans
- Isoenzymes/biosynthesis
- Isoenzymes/deficiency
- Isoenzymes/metabolism
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive
- Membrane Glycoproteins/biosynthesis
- Okadaic Acid
- Phenotype
- Phosphoprotein Phosphatases/antagonists & inhibitors
- Poly A/analysis
- Poly A/metabolism
- Protein Kinase C/biosynthesis
- Protein Kinase C/deficiency
- Protein Kinase C/metabolism
- RNA/analysis
- RNA/metabolism
- RNA, Messenger
- Tumor Cells, Cultured
- Vinblastine/toxicity
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Affiliation(s)
- B Zheng
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322
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42
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Lin SR, Chang KL, Chang CC. Chemical modification of amino groups in cardiotoxin III from Taiwan cobra Naja naja atra) venom. Biochem Mol Biol Int 1993; 31:175-84. [PMID: 8260941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cardiotoxin III (CTX III), a major cardiotoxin analogue isolated from the Taiwan cobra (Naja naja atra) venom was modified, either with trinitrobenzene sulfonate (TNBS) or 4-chloro-3,5-dinitrobenzoate (CDNB). Under the conditions of limited reagent availability, three mono-TNP derivatives modified at Lys-5, 12, or 44, and three mono-CDNP derivatives at Lys-12, 23, or 44 were isolated, respectively. The biological activities of CTX III were more or less affected after each of these reactive amino groups were modified. In particular, the hemolytic activity to human erythrocytes and cytotoxicity on NS-1 cells of CTX III decreased to 31% and 50%, respectively, when Lys-12 was trinitrophenylated. More pronounced alteration in these activities was observed as this amino group was carboxydinitrophenylated. A good correlation between the hemolytic activity and cytotoxicity was found. These results indicate that epsilon-amino group at Lys-12 is most closely related to the hemolytic and cytotoxic activities of CTX III. The antigenicity of modified derivatives still remained intact as measured by ELISA.
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Affiliation(s)
- S R Lin
- School of Chemistry, Kaohsiung Medical College, Taiwan, ROC
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43
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Abstract
Cobra snake venom cardiotoxins and bee venom melittin share a number of pharmacological properties in intact tissues including hemolysis, cytolysis, contractures of muscle, membrane depolarization and activation of tissue phospholipase C and, to a far lesser extent, an arachidonic acid-associated phospholipase A2. The toxins have also been demonstrated to open the Ca2+ release channel (ryanodine receptor) and alter the activity of the Ca(2+)+Mg(2+)-ATPase in isolated sarcoplasmic reticulum preparations derived from cardiac or skeletal muscle. However, a relationship of these actions in isolated organelles to contracture induction has not yet been established. The toxins also bind to and, in some cases, alter the function of a number of other proteins in disrupted tissues. The most difficult tasks in understanding the mechanism of action of these toxins have been dissociating the primary from secondary effects and distinguishing between effects that only occur in disrupted tissues and those that occur in intact tissue. The use of cardiotoxin and melittin fractions contaminated with trace ('undetectable') amounts of venom-derived phospholipases A2 has continued to be common practice, despite the problems associated with the synergism between the toxins and enzymes and the availability of methods to overcome this problem. With adequate precautions taken with regard to methodology and interpretation of results, the cobra venom cardiotoxins and bee venom melittin may prove to be useful probes of a number of cell processes, including lipid metabolism and Ca2+ regulation in skeletal and cardiac muscle.
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Affiliation(s)
- J E Fletcher
- Department of Anesthesiology, Hahnemann University, Philadelphia, PA 19102-1192
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44
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Abstract
Cardiotoxin 1 from cobra (Naja naja atra) venom was tested for its ability to cause necrosis of skeletal muscle cells after i.m. injection into mice. Light and electron microscopic examination of tissue indicated that the toxin caused necrosis of skeletal muscle as early as 30 min after injection. The plasma membranes of affected cells were ruptured in the area of delta lesions, and the myofibrils were condensed into dense clumps alternating with clear areas containing elements of the sarcotubular system and damaged mitochondria. By 24 hr the affected cells appeared as empty 'bags' containing only remnants of myofibrils and swollen mitochondria. To eliminate the possibility that the necrosis was due to contaminating phospholipase A2 (PLA2) activity of the sample, the sample was treated with p-bromophenacyl bromide (p-BPB), a known inhibitor of PLA2 activity. The p-BPB-treated preparation caused myonecrosis in vivo in mice, and the treatment caused a significant decrease in the release of fatty acids and no detectable lysophospholipid in human muscle cell cultures treated in vitro with the preparation, indicating the lack of PLA2 activity. Additionally, purified PLA2 from the same venom failed to cause myonecrosis in vivo at doses equal to or ten times the estimated contaminating concentration. Thus, it is concluded that cardiotoxin 1 from Naja naja atra venom causes necrosis of skeletal muscle cells in vivo upon i.m. injection.
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Affiliation(s)
- C L Ownby
- Department of Physiological Sciences, Oklahoma State University, Stillwater 74078
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45
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Ho CL, Hwang LL, Chen CT. Edema-inducing activity of a lethal protein with phospholipase A1 activity isolated from the black-bellied hornet (Vespa basalis) venom. Toxicon 1993; 31:605-13. [PMID: 7687388 DOI: 10.1016/0041-0101(93)90115-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The lethal protein of the hornet (Vespa basalis) venom is a phospholipase A1 toxin (mol. wt approximately 32,000) with a potent hemolytic activity. Subplantar injection of the toxin caused a dose-dependent swelling in the rat hind paw. Its potency was higher than those of phospholipases A2 and cardiotoxin from cobra venoms. Hind-paw edema induced by the toxin was inhibited by antiserotonin drugs (cyproheptadine and methysergide), indomethacin and betamethasone. Antihistamine (chlorpheniramine) showed a relatively weak inhibition. Intradermal injection of the toxin into back skin of the rat also induced local edema which was inhibited by chlorpheniramine and methysergide. Rats pretreated with multiple doses of compound 48/80 showed a moderate decrease in the histamine and serotonin content of rat skin, and a slight decrease in paw edema induced by the toxin, while a single dose of reserpine markedly diminished the toxin-induced edema in association with depletion of serotonin in rat skin. The edema-inhibitory action of amine-depleting agents appeared to correlate with their potencies to deplete serotonin in the skin. It is suggested that serotonin, prostaglandin E2, and to a lesser extent of histamine are involved in producing the local effect of the toxin. However, serotonin released by the toxin appears to be the major factor mediating the toxin-induced edema in the rat.
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Affiliation(s)
- C L Ho
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan, R.O.C
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46
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Newman RA, Vidal JC, Viskatis LJ, Johnson J, Etcheverry MA. VRCTC-310--a novel compound of purified animal toxins separates antitumor efficacy from neurotoxicity. Invest New Drugs 1993; 11:151-9. [PMID: 8262727 DOI: 10.1007/bf00874149] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Two purified animal venom toxins, crotoxin and cardiotoxin, have been combined to produce a unique natural product (VRCTC-310) currently under investigation as an antitumor agent by the National Cancer Institute. In vitro, it has demonstrated cytotoxic disease specificity and a unique mechanism of action when submitted to COMPARE analysis. In vivo, tolerance was developed to the neurotoxic properties of crotoxin which allowed comparison of several schedules of fixed and escalating daily i.m. doses to mice bearing s.c. Lewis Lung carcinoma. An 83% inhibition of tumor growth was achieved using an escalating dose schedule starting at 1.8 mg/kg and reaching 6.3 mg/kg/day on day 20. Although some irritation around the sites of i.m. injection was noted, animal weight loss was negligible and there were no other signs of adverse toxicity. This natural product represents a new, membrane interactive anticancer agent which produces a unique spectrum of cytotoxicity in vitro and which has demonstrated interesting in vivo antitumor efficacy.
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Affiliation(s)
- R A Newman
- Department of Clinical Investigation, University of Texas M.D. Anderson Cancer Center, Houston
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47
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Chang KL, Chen YS, Lin SR, Chang LS, Chang CC. Probing the functional sites in Naja naja atra (Taiwan cobra) cardiotoxin III with monoclonal antibody. Biochem Mol Biol Int 1993; 29:1015-22. [PMID: 8330009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
One monoclonal antibody (mAb) against Naja naja atra cardiotoxin III was prepared by using the hybridoma technique. The cytotoxic activity of cardiotoxin III which inhibited human lymphocyte proliferation was effectively neutralized by the mAb at a molar ratio of antibody to toxin of 1:2. On the contrary, the mAb did not exert a significant inhibition on the hemolytic activity of cardiotoxin III. These results suggest that the functional site responsible for the cytotoxicity might be different from that for the hemolytic activity of cardiotoxin III.
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Affiliation(s)
- K L Chang
- Department of Biochemistry, Kaohsiung Medical College, Taiwan, ROC
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48
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Ismail M, al-Bekairi AM, el-Bedaiwy AM, Abd-el Salam MA. The ocular effects of spitting cobras: II. Evidence that cardiotoxins are responsible for the corneal opacification syndrome. J Toxicol Clin Toxicol 1993; 31:45-62. [PMID: 8433415 DOI: 10.3109/15563659309000373] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Fractionation of H. haemachatus, N. nigricollis, N. nivea and N. melanoleuca venoms using Amberlite CG-50 and (NH4)HCO3 elution gradient chromatography yielded 11-13 fractions for each venom. One fraction, F X, from H. haemachatus, two fractions, F X and F XI, from N. nigricollis and one fraction, F VIII, from N. melanoleuca venoms possessed the whole of ocular activity of the venoms. The fractions were the only venom fractions that caused cardiac depressant activity; their effect was reversed by raising Ca++ concentration in the physiological solution; they did not influence the twitches of the phrenic nerve hemidiaphragm and guinea-pig ileum preparations. Further purification of the fractions on Sephadex G-50 followed by fractionation on Amberlite CG-50 yielded fractions free from phospholipase A2 activity but possessing the same ocular effects. Similarly, the cardiotoxin from commercial N. nigricollis venom caused the same ocular effects as the crude venom and its purified cardiotoxic fractions. All cardiotoxic fractions as well as N. nigricollis cardiotoxin, caused extensive chemosis, blepharitis and corneal opacification with corneal and subconjunctival neovascularization. On a weight basis, the cardiotoxins were weaker in their oculotoxic activity than the corresponding parent crude venoms possibly because of the potentiating effect of phospholipase A2 in the crude venoms. It is postulated that in spitting cobras the cardiotoxins are responsible for the corneal opacification syndrome. In other cobra venoms the stable binding of cardiotoxins with acidic proteins limits their possible ocular effects. Only in the venoms of the spitting species are the cardiotoxins present in an appropriately free form to cause the ocular opacification syndrome.
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Affiliation(s)
- M Ismail
- Department of Pharmacology, College of Pharmacy, King Saud University, Saudi Arabia
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49
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Fletcher JE, Tripolitis L, Beech J. Species difference in modulation of calcium release by Naja naja kaouthia snake venom cardiotoxin in terminal cisternae from human and equine skeletal muscle. Toxicon 1993; 31:43-51. [PMID: 8446962 DOI: 10.1016/0041-0101(93)90355-m] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The modulation of Ca2+ release by a cardiotoxin (CTX) from Naja naja kaouthia snake venom was examined in terminal cisternae-containing fractions from equine and human skeletal muscle. Pretreatment with CTX (10 microM) decreased by 27% (human muscle), or had no effect on (equine muscle), the threshold of Ca(2+)-induced Ca2+ release. If terminal cisternae fractions were first preloaded with Ca2+ to greater than 65% of the threshold of Ca(2+)-induced Ca2+ release and then CTX added, an immediate and sustained release of Ca2+ occurred in preparations from both species. Addition of CTX after a Ca2+ preload of less than 60% of the threshold of Ca(2+)-induced Ca2+ release did not elicit Ca2+ release in preparations from either species. Ruthenium red (10 microM) antagonized CTX-induced Ca2+ release, whereas dantrolene (10 microM) did not. These findings suggest that the effects of CTX on the Ca2+ release channel are dependent on Ca2+ preload and that CTX may be an important probe of the Ca(2+)-modulated Ca2+ release process and in understanding regulation of Ca2+ release in skeletal muscle from different species.
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Affiliation(s)
- J E Fletcher
- Department of Anesthesiology, Hahnemann University, Philadelphia, PA 19102-1192
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50
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Abstract
Pyrularia thionin is a strongly basic bioactive peptide of 47 amino acids isolated from nuts of Pyrularia pubera. It is hemolytic, cytotoxic and activates an endogenous phospholipase A2 in 3T3 cells. Earlier studies have shown that the cardiotoxin from Naja naja kaouthia has similar activities and binds to the same site as Pyrularia thionin. Since the peptides appear to bind to the phospholipids of cell membranes to elicit their cellular responses, the effect of modifying the electrostatic environment was studied by separately adding phosphate ion and Ca2+, and by removing Ca2+ from the membrane by treatment with EGTA. Analysis of erythrocyte hemolysis for both Pyrularia thionin and cardiotoxin shows that the reactions follow Michaelis-Menten kinetics, with the peptides serving as the substrate. The basal rate of hemolysis in physiological saline is markedly increased by the addition of phosphate in the 5-10 mM range and also by removing membrane-bound Ca2+ by incubation of the cells with 10 mM EGTA. These treatments do not change the apparent K(m) values, but increase the V(max), indicating that more binding sites are made available by these treatments. On the other hand, added Ca2+ in the 5-10 mM range competitively inhibits the reaction by inhibiting the binding of the peptide to the membrane.
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Affiliation(s)
- L P Vernon
- Chemistry Department, Brigham Young University, Provo, UT 84602
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