David E

General

Full name : David Emilie

First name : Emilie

Mail : CHEMFORASE, 1 rue Lucien Tesniere, Batiment IRCOF, Lab research 261, 76130 Mont-Saint-Aignan

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Country : France

Email : emilie.david@chemforase.com

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References (7)

Title : Human butyrylcholinesterase in Cohn fraction IV-4 purified in a single chromatography step on Hupresin - Schopfer_2023_PLoS.One_18_e0280380
Author(s) : Schopfer LM , David E , Hinrichs SH , Lockridge O
Ref : PLoS ONE , 18 :e0280380 , 2023
Abstract : Protection from the toxicity of nerve agents is achieved by pretreatment with human butyrylcholinesterase (BChE). Current methods for purifying large quantities of BChE from frozen Cohn fraction IV-4 produce 99% pure enzyme, but the yield is low (21%). Our goal was to simplify the purification procedure and increase the yield. Butyrylcholinesterase was extracted from frozen Cohn fraction IV-4 in 10 volumes of water pH 6. The filtered extract was pumped onto a Hupresin affinity column. The previously utilized anion exchange chromatography step was omitted. Solvent and detergent reagents used to inactivate lipid enveloped virus, bacteria and protozoa did not bind to Hupresin. BChE was eluted with 0.1 M tetramethylammonium bromide in 20 mM sodium phosphate pH 8.0. BChE protein was concentrated on a Pellicon tangential flow filtration system and demonstrated to be highly purified by mass spectrometry. A high pump rate produced protein aggregates, but a low pump rate caused minimal turbidity. Possible contamination by prekallikrein and prekallikrein activator was examined by LC-MS/MS and by a chromogenic substrate assay for kallikrein activity. Prekallikrein and kallikrein were not detected by mass spectrometry in the 99% pure BChE. The chromogenic assay indicated kallikrein activity was less than 9 mU/mL. This new, 1-step chromatography protocol on Hupresin increased the yield of butyrylcholinesterase by 200%. The new method significantly reduces production costs by optimizing yield of 99% pure butyrylcholinesterase.
ESTHER : Schopfer_2023_PLoS.One_18_e0280380
PubMedSearch : Schopfer_2023_PLoS.One_18_e0280380
PubMedID: 36638134

Title : Purification of human butyrylcholinesterase from frozen Cohn fraction IV-4 by ion exchange and Hupresin affinity chromatography - Schopfer_2019_PLoS.One_14_e0209795
Author(s) : Schopfer LM , Lockridge O , David E , Hinrichs SH
Ref : PLoS ONE , 14 :e0209795 , 2019
Abstract : Human butyrylcholinesterase (HuBChE) is being developed as a therapeutic for protection from the toxicity of nerve agents. An enriched source of HuBChE is Cohn fraction IV-4 from pooled human plasma. For the past 40 years, purification of HuBChE has included affinity chromatography on procainamide-Sepharose. The present report supports a new affinity sorbent, Hupresin, for purification of HuBChE from Cohn fraction IV-4. Nine batches of 70-80 kg frozen Cohn fraction were extracted with water, filtered, and chromatographed on 30 L of Q-Ceramic ion exchange sorbent at pH 4.5. The 4% pure Q-eluent was pumped onto 4.2 L Hupresin, where contaminants were washed off with 0.3 M NaCl in 20 mM sodium phosphate pH 8.0, before 99% pure HuBChE was eluted with 0.1 M tetramethylammonium bromide. The average yield was 1.5 g of HuBChE from 80 kg Cohn paste. Recovery of HuBChE was reduced by 90% when the paste was stored at -20 degrees C for 1 year, and reduced 100% when stored at 4 degrees C for 24h. No reduction in HuBChE recovery occurred when paste was stored at -80 degrees C for 3 months or 3 years. Hupresin and procainamide-Sepharose were equally effective at purifying HuBChE from Cohn fraction. HuBChE in Cohn fraction required 1000-fold purification to attain 99% purity, but 15,000-fold purification when the starting material was plasma. HuBChE (P06276) purified from Cohn fraction was a 340 kDa tetramer of 4 identical N-glycated subunits, stable for years in solution or as a lyophilized product.
ESTHER : Schopfer_2019_PLoS.One_14_e0209795
PubMedSearch : Schopfer_2019_PLoS.One_14_e0209795
PubMedID: 30625168

Title : Purification of recombinant human butyrylcholinesterase on Hupresin(R) - Lockridge_2018_J.Chromatogr.B.Analyt.Technol.Biomed.Life.Sci_1102-1103_109
Author(s) : Lockridge O , David E , Schopfer LM , Masson P , Brazzolotto X , Nachon F
Ref : Journal of Chromatography B Analyt Technol Biomed Life Sciences , 1102-1103 :109 , 2018
Abstract : Affinity chromatography on procainamide-Sepharose has been an important step in the purification of butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) since its introduction in 1978. The procainamide affinity gel has limitations. In the present report a new affinity gel called Hupresin(R) was evaluated for its ability to purify truncated, recombinant human butyrylcholinesterase (rHuBChE) expressed in a stably transfected Chinese Hamster Ovary cell line. We present a detailed example of the purification of rHuBChE secreted into 3940mL of serum-free culture medium. The starting material contained 13,163units of BChE activity (20.9mg). rHuBChE was purified to homogeneity in a single step by passage over 82mL of Hupresin(R) eluted with 0.1M tetramethylammonium bromide in 20mM TrisCl pH7.5. The fraction with the highest specific activity of 630units/mg contained 11mg of BChE. Hupresin(R) is superior to procainamide-Sepharose for purification of BChE, but is not suitable for purifying native AChE because Hupresin(R) binds AChE so tightly that AChE is not released with buffers, but is desorbed with denaturing solvents such as 50% acetonitrile or 1% trifluoroacetic acid. Procainamide-Sepharose will continue to be useful for purification of AChE.
ESTHER : Lockridge_2018_J.Chromatogr.B.Analyt.Technol.Biomed.Life.Sci_1102-1103_109
PubMedSearch : Lockridge_2018_J.Chromatogr.B.Analyt.Technol.Biomed.Life.Sci_1102-1103_109
PubMedID: 30384187

Title : Hupresin Retains Binding Capacity for Butyrylcholinesterase and Acetylcholinesterase after Sanitation with Sodium Hydroxide - Onder_2017_Front.Pharmacol_8_713
Author(s) : Onder S , David E , Tacal O , Schopfer LM , Lockridge O
Ref : Front Pharmacol , 8 :713 , 2017
Abstract : Hupresin is a new affinity resin that binds butyrylcholinesterase (BChE) in human plasma and acetylcholinesterase (AChE) solubilized from red blood cells (RBC). Hupresin is available from the CHEMFORASE company. BChE in human plasma binds to Hupresin and is released with 0.1 M trimethylammonium bromide (TMA) with full activity and 10-15% purity. BChE immunopurified from plasma by binding to immobilized monoclonal beads has fewer contaminating proteins than the one-step Hupresin-purified BChE. However, when affinity chromatography on Hupresin follows ion exchange chromatography at pH 4.5, BChE is 99% pure. The membrane bound AChE, solubilized from human RBC with 0.6% Triton X-100, binds to Hupresin and remains bound during washing with sodium chloride. Human AChE is not released in significant quantities with non-denaturing solvents, but is recovered in 1% trifluoroacetic acid. The denatured, partially purified AChE is useful for detecting exposure to nerve agents by mass spectrometry. Our goal was to determine whether Hupresin retains binding capacity for BChE and AChE after Hupresin is washed with 0.1 M NaOH. A 2 mL column of Hupresin equilibrated in 20 mM TrisCl pH 7.5 was used in seven consecutive trials to measure binding and recovery of BChE from 100 mL human plasma. Between each trial the Hupresin was washed with 10 column volumes of 0.1 M sodium hydroxide. A similar trial was conducted with red blood cell AChE in 0.6% Triton X-100. It was found that the binding capacity for BChE and AChE was unaffected by washing Hupresin with 0.1 M sodium hydroxide. Hupresin could be washed with sodium hydroxide at least seven times without losing binding capacity.
ESTHER : Onder_2017_Front.Pharmacol_8_713
PubMedSearch : Onder_2017_Front.Pharmacol_8_713
PubMedID: 29066970

Title : Dicer Deficiency Differentially Impacts Microglia of the Developing and Adult Brain - Varol_2017_Immunity_46_1030
Author(s) : Varol D , Mildner A , Blank T , Shemer A , Barashi N , Yona S , David E , Boura-Halfon S , Segal-Hayoun Y , Chappell-Maor L , Keren-Shaul H , Leshkowitz D , Hornstein E , Fuhrmann M , Amit I , Maggio N , Prinz M , Jung S
Ref : Immunity , 46 :1030 , 2017
Abstract : Microglia seed the embryonic neuro-epithelium, expand and actively sculpt neuronal circuits in the developing central nervous system, but eventually adopt relative quiescence and ramified morphology in the adult. Here, we probed the impact of post-transcriptional control by microRNAs (miRNAs) on microglial performance during development and adulthood by generating mice lacking microglial Dicer expression at these distinct stages. Conditional Dicer ablation in adult microglia revealed that miRNAs were required to limit microglial responses to challenge. After peripheral endotoxin exposure, Dicer-deficient microglia expressed more pro-inflammatory cytokines than wild-type microglia and thereby compromised hippocampal neuronal functions. In contrast, prenatal Dicer ablation resulted in spontaneous microglia activation and revealed a role for Dicer in DNA repair and preservation of genome integrity. Accordingly, Dicer deficiency rendered otherwise radio-resistant microglia sensitive to gamma irradiation. Collectively, the differential impact of the Dicer ablation on microglia of the developing and adult brain highlights the changes these cells undergo with time.
ESTHER : Varol_2017_Immunity_46_1030
PubMedSearch : Varol_2017_Immunity_46_1030
PubMedID: 28636953

Title : Microglia development follows a stepwise program to regulate brain homeostasis - Matcovitch-Natan_2016_Science_353_aad8670
Author(s) : Matcovitch-Natan O , Winter DR , Giladi A , Vargas Aguilar S , Spinrad A , Sarrazin S , Ben-Yehuda H , David E , Zelada Gonzalez F , Perrin P , Keren-Shaul H , Gury M , Lara-Astaiso D , Thaiss CA , Cohen M , Bahar Halpern K , Baruch K , Deczkowska A , Lorenzo-Vivas E , Itzkovitz S , Elinav E , Sieweke MH , Schwartz M , Amit I
Ref : Science , 353 :aad8670 , 2016
Abstract : Microglia, the resident myeloid cells of the central nervous system, play important roles in life-long brain maintenance and in pathology. Despite their importance, their regulatory dynamics during brain development have not been fully elucidated. Using genome-wide chromatin and expression profiling coupled with single-cell transcriptomic analysis throughout development, we found that microglia undergo three temporal stages of development in synchrony with the brain--early, pre-, and adult microglia--which are under distinct regulatory circuits. Knockout of the gene encoding the adult microglia transcription factor MAFB and environmental perturbations, such as those affecting the microbiome or prenatal immune activation, led to disruption of developmental genes and immune response pathways. Together, our work identifies a stepwise microglia developmental program integrating immune response pathways that may be associated with several neurodevelopmental disorders.
ESTHER : Matcovitch-Natan_2016_Science_353_aad8670
PubMedSearch : Matcovitch-Natan_2016_Science_353_aad8670
PubMedID: 27338705

Title : A straightforward and highly diastereoselective access to functionalized monofluorinated cyclopropanes via a Michael initiated ring closure reaction - Ferrary_2013_Org.Lett_15_5598
Author(s) : Ferrary T , David E , Milanole G , Besset T , Jubault P , Pannecoucke X
Ref : Org Lett , 15 :5598 , 2013
Abstract : The synthesis of highly functionalized monofluorinated cyclopropanes based on a Michael Initiated Ring Closure (MIRC) reaction has been developed. The addition of quaternary ammonium salts derived from ethyl bromofluoroacetate on a panel of electron deficient alkenes followed by cyclization gave rise to an efficient access to monofluorinated cyclopropanes with good yields and remarkable diastereoselectivity.
ESTHER : Ferrary_2013_Org.Lett_15_5598
PubMedSearch : Ferrary_2013_Org.Lett_15_5598
PubMedID: 24138105