(07) In vitro and in vivo characterization of recombinant human butyrylcholinesterase (Protexia™) as a potential nerve agent bioscavenger

Cerasoli, Douglas M.; Griffiths, E; Doctor, Bhupendra P.; Saxena, Ashima; Fedorko, James M.; Greig, Nigel H.; Yu, Qian‐sheng; Huang, Yadong; Wilgus, H. S.; Karatzas, C.N.; Koplovitz, Irwin; Lenz, David E.

doi:10.1016/j.cbi.2005.10.052

Cited by 61 publications

(44 citation statements)

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“…As such, the use of a human enzyme for such a purpose would be expected to avoid potentially harmful immune responses that may arise from protein-based therapies derived from nonhuman sources. Extensive work has been conducted toward this goal with a recombinant form of BuChE purified from the milk of transgenic goats (49,53). While this enzyme has been shown to confer a level of protection up to 5.5 × LD 50 for VX and soman in guinea pigs (49), it acts purely as a stoichiometric bioscavenger and binds to, but does not catalytically inactivate, nerve agents.…”

Section: Discussionmentioning

confidence: 99%

Crystal Structures of Human Carboxylesterase 1 in Covalent Complexes with the Chemical Warfare Agents Soman and Tabun^,

et al. 2007

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The organophosphorus nerve agents sarin, soman, tabun, and VX exert their toxic effects by inhibiting the action of human acetylcholinesterase, a member of the serine hydrolase superfamily of enzymes. The current treatments for nerve agent exposure must be administered quickly to be effective and they often do not eliminate long-term toxic side effects associated with organophosphate poisoning. Thus, there is significant need for effective prophylactic methods to protect at-risk personnel from nerve agent exposure, and protein-based approaches have emerged as promising candidates. We present the 2.7 Å resolution crystal structures of the serine hydrolase human carboxylesterase 1 (hCE1), a broad-spectrum drug metabolism enzyme, in covalent acylenzyme intermediate complexes with the chemical weapons soman and tabun. The structures reveal that hCE1 binds stereoselectively to these nerve agents; for example, hCE1 appears to react preferentially with the 10 4 -fold more lethal P S stereoisomer of soman relative to the P R form. In addition, structural features of the hCE1 active site indicate that the enzyme may be resistant to deadend organophosphate aging reactions that permanently inactivate other serine hydrolases. Taken together, these data provide important structural details toward the goal of engineering hCE1 into an organophosphate hydrolase and protein-based therapeutic for nerve agent exposure.The organophosphorus (OP) nerve agents sarin, soman, tabun, and VX are among the deadliest man-made chemicals (1). While the military use of OP nerve agents is widely banned, these compounds have been employed in recent decades by rogue states and terrorist groups. In 1988, Iraq employed weaponized sarin against its own Kurdish citizens in Halabja, a town adjacent to the Iranian border, killing an estimated 5,000 (2). Coordinated attacks on the Tokyo subway system by the Japanese Aum Shinrikyo cult in 1995 also employed sarin, killing 12 and injuring † This work was supported, in part, by NIH grants CA98468 and NS58089, and the American Lebanese Syrian Associated Charities. ‡ Protein Data Bank codes are 2HRQ for the hCE1-soman structure and 2HRR for the hCE1-tabun structure. *Corresponding Author: Matthew R. Redinbo, Ph.D., Department of Chemistry, CB #3290, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290, (919)843-8910; Fax: (919)962-2388, redinbo@unc.edu. 1 Abbreviations: AcChE, Human acetylcholinesterase; BuChE, Human butyrylcholinesterase; CE, carboxylesterase; hCE1, Human carboxylesterase 1; HI-6, 1-(2-hydroxy-iminomethylpyridinium)-1-(4-carboxyamino)-pyridinium dimethylether dichloride; MuAcChE, Mus musculus acetylcholinesterase; OP, organophosphate; Ortho-7, 1,7-heptylene-bis-N,N′-2-pyridiniumaldoxime dichloride; PON1, human serum paraoxonase 1; rmsd, root mean square deviation; Sarin, methylethyl methylphosphonofluoridate; Soman, Tabun, ethyl N, TcAcChE, Torpedo californica acetylcholinesterase; VX, OP toxicity is thought to be mediated through the inhibition of human acety...

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Section: Discussionmentioning

confidence: 99%

Crystal Structures of Human Carboxylesterase 1 in Covalent Complexes with the Chemical Warfare Agents Soman and Tabun^,

et al. 2007

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“…The VX challenge data obtained with MoBChE through the adenovirus system compares favorably with those obtained with natural or recombinant purified BChE injected into monkeys, rats, mice, and guinea pigs for protection against sarin, cyclosarin, soman, or VX (Broomfield et al, 1991;Wolfe et al, 1992;Raveh et al, 1993Raveh et al, , 1997Cerasoli et al, 2005;Lenz et al, 2005). The protection range, obtained through injection of multiple-milligram amounts per kilogram of animal body weight, covered 1ϫ to 5.5ϫ LD 50 of the agents.…”

Section: Discussionmentioning

confidence: 89%

Gene-Delivered Butyrylcholinesterase Is Prophylactic against the Toxicity of Chemical Warfare Nerve Agents and Organophosphorus Compounds

Parikh¹,

Duysen

Snow

et al. 2010

J Pharmacol Exp Ther

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Gene delivery using an adenoviral system has been effective in introducing therapeutic proteins in vitro and in vivo. This study tested the feasibility of using adenovirus to deliver clinically relevant amounts of butyrylcholinesterase (BChE), a proven bioscavenger of nerve agents. The adenovirus construct expressed full-length mouse BChE. Mice were injected with a single dose of adenovirus (1.5 ϫ 10 10 infectious units) in the tail vein; plasma was collected through day 11 and assayed for BChE activity. Maximum activity, representing a 300-to 3400-fold increase over baseline, was found on day 4. Expression levels returned to baseline by day 10. Nondenaturing gel electrophoresis showed the recombinant BChE was a dimer that could be converted to tetramers by addition of polyproline. The toxic compounds chosen for protection studies were positively charged organophosphorus agents, echothiophate, and O-ethyl-S-2-N,N-diisopropylaminoethyl methylphosphonothiolate (VX). Mice containing elevated blood levels of BChE (300-to 3,000-fold over the control mice) were challenged with incremental doses of echothiophate or VX. Mice showed no signs of toxicity and were protected from up to 30ϫ LD 50 dose of echothiophate and 5ϫ LD 50 dose of VX. A good correlation was observed between tolerated echothiophate dose and plasma BChE levels at time of challenge. The absolute increases in levels of circulating BChE and the sustained nature of the response resulted in a very high enzyme concentration, deemed critical in acute toxicity (5ϫ LD 50 or more) scenarios. These results suggest that gene-delivered BChE is a prophylactic and affords protection equivalent to that of a multimilligram injection of the same.

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“…These animals produce relatively high quantities of recombinant proteins compared to other conventional methods due to the physiological nature of the mammary gland for its unique ability to synthesize proteins [84,78,85,86,87,88]. A few examples of transgenic small ruminants producing recombinant proteins in milk for pharmaceutical and biomedical interest are sheep producing human clotting factor VIII [89] and factor IX [82] and goats synthesizing human antithrombin III [90], human alpha-fetoprotein [91], human monoclonal antibodies [92,93], malaria antigens [94] spider silks [95], human granulocyte colony stimulating factor (96) and human butyryl-cholinesterase [97,98]. Although these animals have shown high expression of the transgene product in the milk, a recent report suggests that the transgene may have some negative effects on the physiology of mammary gland function, leading to a compromised situation [87].…”

Section: Production Of Transgenic Sheep and Goatsmentioning

confidence: 99%

Recent Advances in Reproductive Biotechnologies in Sheep and Goat

Alexander¹,

Mastromonaco²,

King³

2010

J Veterinar Sci Technolo

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(07) In vitro and in vivo characterization of recombinant human butyrylcholinesterase (Protexia™) as a potential nerve agent bioscavenger

Cited by 61 publications

References 4 publications

Crystal Structures of Human Carboxylesterase 1 in Covalent Complexes with the Chemical Warfare Agents Soman and Tabun^,

Crystal Structures of Human Carboxylesterase 1 in Covalent Complexes with the Chemical Warfare Agents Soman and Tabun^,

Gene-Delivered Butyrylcholinesterase Is Prophylactic against the Toxicity of Chemical Warfare Nerve Agents and Organophosphorus Compounds

Recent Advances in Reproductive Biotechnologies in Sheep and Goat

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(07) In vitro and in vivo characterization of recombinant human butyrylcholinesterase (Protexia™) as a potential nerve agent bioscavenger

Cited by 61 publications

References 4 publications

Crystal Structures of Human Carboxylesterase 1 in Covalent Complexes with the Chemical Warfare Agents Soman and Tabun,

Crystal Structures of Human Carboxylesterase 1 in Covalent Complexes with the Chemical Warfare Agents Soman and Tabun,

Gene-Delivered Butyrylcholinesterase Is Prophylactic against the Toxicity of Chemical Warfare Nerve Agents and Organophosphorus Compounds

Recent Advances in Reproductive Biotechnologies in Sheep and Goat

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Crystal Structures of Human Carboxylesterase 1 in Covalent Complexes with the Chemical Warfare Agents Soman and Tabun^,

Crystal Structures of Human Carboxylesterase 1 in Covalent Complexes with the Chemical Warfare Agents Soman and Tabun^,