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Steven H Zeisel - One of the best experts on this subject based on the ideXlab platform.
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betaine is accumulated via transient Choline Dehydrogenase activation during mouse oocyte meiotic maturation
Journal of Biological Chemistry, 2017Co-Authors: Taylor Mcclatchie, Megan Meredith, Mariame Ouedraogo, Sandy Slow, Michael Lever, Mellissa R W Mann, Steven H ZeiselAbstract:Betaine (N,N,N-trimethylglycine) plays key roles in mouse eggs and preimplantation embryos first in a novel mechanism of cell volume regulation and second as a major methyl donor in blastocysts, but its origin is unknown. Here, we determined that endogenous betaine was present at low levels in germinal vesicle (GV) stage mouse oocytes before ovulation and reached high levels in the mature, ovulated egg. However, no betaine transport into oocytes was detected during meiotic maturation. Because betaine can be synthesized in mammalian cells via Choline Dehydrogenase (CHDH; EC 1.1.99.1), we assessed whether this enzyme was expressed and active. Chdh transcripts and CHDH protein were expressed in oocytes. No CHDH enzyme activity was detected in GV oocyte lysate, but CHDH became highly active during oocyte meiotic maturation. It was again inactive after fertilization. We then determined whether oocytes synthesized betaine and whether CHDH was required. Isolated maturing oocytes autonomously synthesized betaine in vitro in the presence of Choline, whereas this failed to occur in Chdh-/- oocytes, directly demonstrating a requirement for CHDH for betaine accumulation in oocytes. Overall, betaine accumulation is a previously unsuspected physiological process during mouse oocyte meiotic maturation whose underlying mechanism is the transient activation of CHDH.
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Choline Dehydrogenase polymorphism rs12676 is a functional variation and is associated with changes in human sperm cell function
PLOS ONE, 2012Co-Authors: Amy R Johnson, Sai Lao, Tongwen Wang, Joseph A Galanko, Steven H ZeiselAbstract:Approximately 15% of couples are affected by infertility and up to half of these cases arise from male factor infertility. Unidentified genetic aberrations such as chromosomal deletions, translocations and single nucleotide polymorphisms (SNPs) may be the underlying cause of many cases of idiopathic male infertility. Deletion of the Choline Dehydrogenase (Chdh) gene in mice results in decreased male fertility due to diminished sperm motility; sperm from Chdh−/− males have decreased ATP concentrations likely stemming from abnormal sperm mitochondrial morphology and function in these cells. Several SNPs have been identified in the human CHDH gene that may result in altered CHDH enzymatic activity. rs12676 (G233T), a non-synonymous SNP located in the CHDH coding region, is associated with increased susceptibility to dietary Choline deficiency and risk of breast cancer. We now report evidence that this SNP is also associated with altered sperm motility patterns and dysmorphic mitochondrial structure in sperm. Sperm produced by men who are GT or TT for rs12676 have 40% and 73% lower ATP concentrations, respectively, in their sperm. rs12676 is associated with decreased CHDH protein in sperm and hepatocytes. A second SNP located in the coding region of IL17BR, rs1025689, is linked to altered sperm motility characteristics and changes in Choline metabolite concentrations in sperm.
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deletion of murine Choline Dehydrogenase results in diminished sperm motility
The FASEB Journal, 2010Co-Authors: Amy R Johnson, Corneliu N Craciunescu, Zhong Guo, Ya Wen Teng, Randy J Thresher, Jan Krzysztof Blusztajn, Steven H ZeiselAbstract:Choline Dehydrogenase (CHDH) cata- lyzes the conversion of Choline to betaine, an important methyl donor and organic osmolyte. We have previ- ously identified single nucleotide polymorphisms (SNPs) in the human CHDH gene that, when present, seem to alter the activity of the CHDH enzyme. These SNPs occur frequently in humans. We created a Chdh / mouse to determine the functional effects of mutations that result in decreased CHDH activity. Chdh deletion did not affect fetal viability or alter growth or survival of these mice. Only one of eleven Chdh / males was able to reproduce. Loss of CHDH activity resulted in decreased testicular betaine and increased Choline and PCho concentrations. Chdh / and Chdh / mice produced comparable amounts of sperm; the impaired fertility was due to diminished sperm motility in the Chdh / males. Transmission electron micros- copy revealed abnormal mitochondrial morphology in Chdh / sperm. ATP content, total mitochondrial de- hydrogenase activity and inner mitochondrial mem- brane polarization were all significantly reduced in sperm from Chdh / animals. Mitochondrial changes were also detected in liver, kidney, heart, and testis tissues. We suggest that men who have SNPs in CHDH that decrease the activity of the CHDH enzyme could have decreased sperm motility and fertility.— Johnson, A. R., Craciunescu, C. N., Guo, Z., Teng, Y.-W., Thresher, R. J., Blusztajn, J. K., Zeisel, S. H. Deletion of murine Choline Dehydrogenase results in diminished sperm motility. FASEB J. 24, 000 - 000 (2010). www.fasebj.org
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common genetic polymorphisms affect the human requirement for the nutrient Choline
The FASEB Journal, 2006Co-Authors: Kerry Ann Da Costa, Joseph A Galanko, Olga G Kozyreva, Jiannan Song, Leslie M Fischer, Steven H ZeiselAbstract:Humans eating diets deficient in the essential nutrient Choline can develop organ dysfunction. We hypothesized that common single nucleotide polymorphisms (SNPs) in genes involved in Choline metabolism influence the dietary requirement of this nutrient. Fifty-seven humans were fed a low Choline diet until they developed organ dysfunction or for up to 42 days. We tested DNA SNPs for allelic association with susceptibility to developing organ dysfunction associated with Choline deficiency. We identified an SNP in the promoter region of the phosphatidylethanolamine N-methyltransferase gene (PEMT; −744 G→C; rs12325817) for which 18 of 23 carriers of the C allele (78%) developed organ dysfunction when fed a low Choline diet (odds ratio 25, P=0.002). The first of two SNPs in the coding region of the Choline Dehydrogenase gene (CHDH; +318 A→C; rs9001) had a protective effect on susceptibility to Choline deficiency, while a second CHDH variant (+432 G→T; rs12676) was associated with increased susceptibility to ch...
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measurement of the formation of betaine aldehyde and betaine in rat liver mitochondria by a high pressure liquid chromatography radioenzymatic assay
Biochimica et Biophysica Acta, 1992Co-Authors: Jan K Blustzjn, Jing Zhang, Steven H ZeiselAbstract:A new assay procedure for measurement of rat liver mitochondrial Choline Dehydrogenase was developed. Oxidation of [methyl-14C]Choline to [methyl-14C]betaine aldehyde and [methyl-14C]betaine was measured after isolating these compounds using HPLC. We observed that NAD+ was required for conversion of betaine aldehyde to betaine in rat liver mitochondria. In the absence of this cofactor, oxidation of Choline led to the accumulation of betaine aldehyde. The apparent Km of the mitochondrial Choline Dehydrogenase for Choline was 0.14-0.27 mM, which is significantly lower than previously reported. A partially purified preparation of Choline Dehydrogenase catalyzed betaine aldehyde formation only in the presence of exogenous electron acceptors (e.g., phenazine methosulfate). This preparation failed to catalyze the formation of betaine even in the presence of NAD+, indicating that betaine aldehyde Dehydrogenase may be a separate enzyme from Choline Dehydrogenase.
Leif Bulow - One of the best experts on this subject based on the ideXlab platform.
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enhanced stress tolerance in escherichia coli and nicotiana tabacum expressing a betaine aldehyde Dehydrogenase Choline Dehydrogenase fusion protein
Biotechnology Progress, 2002Co-Authors: Jenny Lindberg Yilmaz, Leif BulowAbstract:In Escherichia coli the osmoprotective compound glycine betaine is produced from Choline by two enzymes; Choline Dehydrogenase (CDH) oxidizes Choline to betaine aldehyde and then further on to glycine betaine, while betaine aldehyde Dehydrogenase (BADH) facilitates the conversion of betaine aldehyde to glycine betaine. To evaluate the importance of BADH, a BADH/CDH fusion enzyme was constructed and expressed in E. coli and in Nicotiana tabacum. The fusion enzyme displayed both enzyme activities, and a coupled reaction could be measured. The enzyme was characterized regarding molecular weight and the dependence of the enzyme activities on environmental factors (salt, pH, and poly(ethylene glycol) addition). At high Choline concentrations, E. coli cells expressing BADH/CDH were able to grow to higher final densities and to accumulate more glycine betaine than cells expressing CDH only. The intracellular glycine betaine levels were almost 5-fold higher for BADH/CDH when product concentration was related to CDH activity. Also, after culturing the cells at high NaCl concentrations, more glycine betaine was accumulated. On medium containing 20 mM Choline, transgenic tobacco plants expressing BADH/CDH grew considerably faster than vector-transformed control plants.
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enhanced nacl stress tolerance in transgenic tobacco expressing bacterial Choline Dehydrogenase
Nature Biotechnology, 1996Co-Authors: Gosta Lilius, Niklas Holmberg, Leif BulowAbstract:The intracellular accumulation of osmoprotectants, such as glycine betaine and other low molecular weight compounds, is a well investigated response of environmental stress occurring in a wide range of organisms. By introducing the bacterial bet A gene, encoding Choline Dehydrogenase (CDH), into tobacco both a salt and Choline resistant phenotype was achieved. As measured by dried weights, there was an 80% increase in salt tolerance between the transgenic and wild-type plants at 300 mM NaCl.
Qishui Lin - One of the best experts on this subject based on the ideXlab platform.
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functional expression and processing of rat Choline Dehydrogenase precursor
Biochemical and Biophysical Research Communications, 2003Co-Authors: Shengbing Huang, Qishui LinAbstract:Choline Dehydrogenase (CHDH, EC 1.1.99.1) was purified from rat liver mitochondria, and the amino terminal sequence was determined and used to clone a full-length cDNA encoding a protein precursor (CHDHp) of 599 amino acids (64 kDa). Sequence analysis identified a possible processing site that meets the requirements of IMP in comparison to the previously determined N-terminal sequence of mature rat CHDH. This suggested that the precursor might be processed in the intermembrane space. Confocal imaging showed that expression of the CHDHp-GFP fusion gene in NIH-3T3 cells led to fusion proteins being targeted to mitochondria. In addition, expression of a recombinant version of the CHDHp gene in Saccharomyces cerevisiae led to enrichment of the target protein in the mitochondrial inner membrane. The expressed protein conferred Choline Dehydrogenase activity, suggesting that both functional domains (FAD and the iron sulfur cluster) were properly assembled and that the mature CHDH was appropriately located in the inner mitochondria membrane. (C) 2003 Published by Elsevier Inc.
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studies on the denaturation and conformation of Choline Dehydrogenase
Acta Biochimica et Biophysica Sinica, 1997Co-Authors: Peng Cai, Qishui LinAbstract:The substrate Choline was able to improve the pH stability of Choline Dehydrogenase (CDH). It was found that during the thermal denaturation there were an increase of beta-structure and a decrease of the alpha-helix content. Changes in beta-structure were attributed to beta-turn and 3(10)-helix. The substrate had a protective effect on CDH thermal denaturation. The proportion of 3(10)-helix content of the SDS-denatured protein and that in the presence of substrate was 33% and 31.2% respectively; while, the corresponding proportion of beta-sheet was 29% and 10.6%, respectively. Moreover, when the absorption proportion of alpha-helix, random coil and the side-chain of tyrosine residues were concerned, it was found that the spectral property of the CDH treated by denaturants in the presence of substrate were rather similar to that of the non-denatured enzyme.
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kinetic properties of Choline Dehydrogenase
Acta Biochimica et Biophysica Sinica, 1997Co-Authors: Qishui LinAbstract:The kinetic behavior of purified CDH had been investigated by steady-state initial velocity studies and inhibition studies with products. Variations in the concentration of one substrate led to changes in the K(m) and V(max) for the other substrate. The product betaine aldehyde was a noncompetitive inhibitor with respect to Choline, whereas it competed with PMS. The results were consistent with a Bi-Bi Ping-Pong mechanism. 1-PC (1-pyrenebutyrylCholine bromide) and 9-AC (9-anthrolCholine bromide) behaved as mixed inhibitors, with K(i) values of 0.3 mM and 3.67 mM respectively.
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studies on the spectral properties of Choline Dehydrogenase
Acta Biochimica et Biophysica Sinica, 1997Co-Authors: Qishui LinAbstract:The addition of the substrate didn't show any influence on the intrinsic emission spectra of purified CDH, which had a maximum at 335 nm. On the other hand, the 520 nm fluorescence of CDH increased after the addition of substrate. The secondary structure of solubilized CDH was examined by Fourier-transform infrared spectroscopy. The percentage distribution of its secondary structure assignment had been obtained: 53.4% alpha-helix, 24.5% beta-sheet, 13.9% 3(10)-helix and 0.5% beta-turn. The predominant conformation of CDH was alpha-helix and beta-sheet when there was no substrate. After the addition of substrate, the percentage of 3(10)-helix structure increased to 42%, whereas that of alpha-helix structure decreased to 35%, indicating that the conformation of CDH changed significantly after the binding of substrate of substrate to the enzyme.
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the protection of Choline Dehydrogenase by its substrate
Acta Biochimica et Biophysica Sinica, 1996Co-Authors: Qishui LinAbstract:Choline Dehydrogenase, an enzyme bound to the mitochondrial inner membrane, plays an important role in the mitochondrial respiratory chain. The purified enzyme is different from the membrane bound enzyme in some properties. The inactivation effects of temperature and SDS on Choline Dehydrogenase were studied. It was found that the substrate Choline had significant protective effect. It was suggested that its substrate could induce the conformational changes of Choline Dehydrogenase.
Jing Zhang - One of the best experts on this subject based on the ideXlab platform.
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measurement of the formation of betaine aldehyde and betaine in rat liver mitochondria by a high pressure liquid chromatography radioenzymatic assay
Biochimica et Biophysica Acta, 1992Co-Authors: Jan K Blustzjn, Jing Zhang, Steven H ZeiselAbstract:A new assay procedure for measurement of rat liver mitochondrial Choline Dehydrogenase was developed. Oxidation of [methyl-14C]Choline to [methyl-14C]betaine aldehyde and [methyl-14C]betaine was measured after isolating these compounds using HPLC. We observed that NAD+ was required for conversion of betaine aldehyde to betaine in rat liver mitochondria. In the absence of this cofactor, oxidation of Choline led to the accumulation of betaine aldehyde. The apparent Km of the mitochondrial Choline Dehydrogenase for Choline was 0.14-0.27 mM, which is significantly lower than previously reported. A partially purified preparation of Choline Dehydrogenase catalyzed betaine aldehyde formation only in the presence of exogenous electron acceptors (e.g., phenazine methosulfate). This preparation failed to catalyze the formation of betaine even in the presence of NAD+, indicating that betaine aldehyde Dehydrogenase may be a separate enzyme from Choline Dehydrogenase.
Beate Averhoff - One of the best experts on this subject based on the ideXlab platform.
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the Choline Dehydrogenase beta of acinetobacter baumannii a flavoprotein responsible for osmotic stress protection
Environmental Microbiology, 2021Co-Authors: Jennifer Breisch, Melanie Bendel, Beate AverhoffAbstract:Acinetobacter baumannii is outstanding for its ability to cope with low water activities which significantly contributes to its persistence in hospital environments. The vast majority of bacteria are able to prevent loss of cellular water by amassing osmoactive compatible solutes or their precursors into the cytoplasm. One such precursor of an osmoprotectant is Choline that is taken up from the environment and oxidized to the compatible solute glycine betaine. Here, we report the identification of the osmotic stress operon betIBA in A. baumannii. This operon encodes the Choline oxidation pathway important for the production of the solute glycine betaine. The salt-sensitive phenotype of a betA deletion strain could not be rescued by addition of Choline, which is consistent with the role of BetA in Choline oxidation. We found that BetA is a Choline Dehydrogenase but also mediates in vitro the oxidation of glycine betaine aldehyde to glycine betaine. BetA was found to be associated with the membrane and to contain a flavin, indicative for BetA donating electrons into the respiratory chain. The Choline Dehydrogenase activity was not salt dependent but was stimulated by the compatible solute glutamate.
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osmotic stress response in acinetobacter baylyi identification of a glycine betaine biosynthesis pathway and regulation of osmoadaptive Choline uptake and glycine betaine synthesis through a Choline responsive beti repressor
Environmental Microbiology Reports, 2016Co-Authors: Anica Scholz, Volker Muller, Julia Stahl, Veronique De Berardinis, Beate AverhoffAbstract:Acinetobacter baylyi, a ubiquitous soil bacterium, can cope with high salinity by uptake of Choline as precursor of the compatible solute glycine betaine. Here, we report on the identification of a Choline Dehydrogenase (BetA) and a glycine betaine aldehyde Dehydrogenase (BetB) mediating the oxidation of Choline to glycine betaine. The betAB genes were found to form an operon together with the potential transcriptional regulator betI. The transcription of the betIBA operon and the two recently identified Choline transporters was upregulated in response to Choline and Choline plus salt. The finding that the osmo-independent transporter BetT1 undergoes a higher upregulation in response to Choline alone than betT2 suggests that BetT1 does not primarily function in osmoadaptation. Electrophoretic mobility shift assays led to the conclusion that BetI mediates transcriptional regulation of both, the betIBA gene operon and the Choline transporters. BetI was released from the DNA in response to Choline which together with the transcriptional upregulation of the bet genes in the presence of Choline suggests that BetI is a Choline sensing transcriptional repressor.