RESUMO
Chardonnay is one of the most popular white grape wine varieties in the world, but this wine lacks typical aroma, considered a sensory defect. Our research group identified a Chardonnay bud sport with typical muscat characteristics. The goal of this work was to discover the key candidate genes related to muscat characteristics in this Chardonnay bud sport to reveal the mechanism of muscat formation and guide molecular design breeding. To this end, HS-SPME-GC-MS and RNA-Seq were used to analyze volatile organic compounds and the differentially expressed genes in Chardonnay and its aromatic bud sport. Forty-nine volatiles were identified as potential biomarkers, which included mainly aldehydes and terpenes. Geraniol, linalool, and phenylacetaldehyde were identified as the main aroma components of the mutant. The GO, KEGG, GSEA, and correlation analysis revealed HMGR, TPS1, TPS2, TPS5, novel.939, and CYP450 as key genes for terpene synthesis. MAO1 and MAO2 were significantly downregulated, but there was an increased content of phenylacetaldehyde. These key candidate genes provide a reference for the development of functional markers for muscat varieties and also provide insight into the formation mechanism of muscat aroma.
Assuntos
Metaboloma , Odorantes , Transcriptoma , Compostos Orgânicos Voláteis , Odorantes/análise , Compostos Orgânicos Voláteis/metabolismo , Compostos Orgânicos Voláteis/análise , Vitis/genética , Vitis/química , Vitis/metabolismo , Vinho/análise , Terpenos/metabolismo , Perfilação da Expressão Gênica , Monoterpenos Acíclicos/metabolismo , Regulação da Expressão Gênica de Plantas , Cromatografia Gasosa-Espectrometria de Massas , Acetaldeído/análogos & derivados , Acetaldeído/metabolismo , Monoaminoxidase/genética , Monoaminoxidase/metabolismoRESUMO
BACKGROUND: Aldehyde dehydrogenase 2 (ALDH2) is critical for alcohol metabolism by converting acetaldehyde to acetic acid. In East Asian descendants, an inactive genetic variant in ALDH2, rs671, triggers an alcohol flushing response due to acetaldehyde accumulation. As alcohol flushing is not exclusive to those of East Asian descent, we questioned whether additional ALDH2 genetic variants can drive facial flushing and inefficient acetaldehyde metabolism using human testing and biochemical assays. METHODS: After IRB approval, human subjects were given an alcohol challenge (0.25 g/kg) while quantifying acetaldehyde levels and the physiological response (heart rate and skin temperature) to alcohol. Further, by employing biochemical techniques including human purified ALDH2 proteins and transiently transfected NIH 3T3 cells, we characterized two newly identified ALDH2 variants for ALDH2 enzymatic activity, ALDH2 dimer/tetramer formation, and reactive oxygen species production after alcohol treatment. RESULTS: Humans heterozygous for rs747096195 (R101G) or rs190764869 (R114W) had facial flushing and a 2-fold increase in acetaldehyde levels, while rs671 (E504K) had facial flushing and a 6-fold increase in acetaldehyde levels relative to wild type ALDH2 carriers. In vitro studies with recombinant R101G and R114W ALDH2 enzyme showed a reduced efficiency in acetaldehyde metabolism that is unique when compared to E504K or wild-type ALDH2. The effect is caused by a lack of functional dimer/tetramer formation for R101G and decreased Vmax for both R101G and R114W. Transiently transfected NIH-3T3 cells with R101G and R114W also had a reduced enzymatic activity by ~ 50% relative to transfected wild-type ALDH2 and when subjected to alcohol, the R101G and R114W variants had a 2-3-fold increase in reactive oxygen species formation with respect to wild type ALDH2. CONCLUSIONS: We identified two additional ALDH2 variants in humans causing facial flushing and acetaldehyde accumulation after alcohol consumption. As alcohol use is associated with a several-fold higher risk for esophageal cancer for the E504K variant, the methodology developed here to characterize ALDH2 genetic variant response to alcohol can lead the way precision medicine strategies to further understand the interplay of alcohol consumption, ALDH2 genetics, and cancer.
Assuntos
Acetaldeído , Aldeído-Desidrogenase Mitocondrial , Etanol , Variação Genética , Acetaldeído/metabolismo , Humanos , Aldeído-Desidrogenase Mitocondrial/genética , Aldeído-Desidrogenase Mitocondrial/metabolismo , Animais , Camundongos , Etanol/metabolismo , Células NIH 3T3 , Espécies Reativas de Oxigênio/metabolismo , Masculino , Adulto , Feminino , Rubor/metabolismo , Rubor/genéticaRESUMO
3,3,3-Trifluoro-1,2-propanediol undergoes complete defluorination in two distinct steps: first, the conversion into 3,3,3-trifluoropropionaldehyde catalyzed by adenosylcobalamin (coenzyme B12)-dependent diol dehydratase; second, non-enzymatic elimination of all three fluorides from this aldehyde to afford malonic semialdehyde (3-oxopropanoic acid), which is decarboxylated to acetaldehyde. Diol dehydratase accepts 3,3,3-trifluoro-1,2-propanediol as a relatively poor substrate, albeit without significant mechanism-based inactivation of the enzyme during catalysis. Optical and electron paramagnetic resonance (EPR) spectra revealed the steady-state formation of cob(II)alamin and a substrate-derived intermediate organic radical (3,3,3-trifluoro-1,2-dihydroxyprop-1-yl). The coenzyme undergoes Co-C bond homolysis initiating a sequence of reaction by the generally accepted pathway via intermediate radicals. However, the greater steric size of trifluoromethyl and especially its negative impact on the stability of an adjacent radical centre compared to a methyl group has implications for the mechanism of the diol dehydratase reaction. Nevertheless, 3,3,3-trifluoropropionaldehyde is formed by the normal diol dehydratase pathway, but then undergoes non-enzymatic conversion into acetaldehyde, probably via 3,3-difluoropropenal and malonic semialdehyde.
Assuntos
Acetaldeído , Cobamidas , Propanodiol Desidratase , Acetaldeído/metabolismo , Acetaldeído/química , Propanodiol Desidratase/metabolismo , Propanodiol Desidratase/química , Cobamidas/metabolismo , Cobamidas/química , Fluoretos/metabolismo , Fluoretos/química , Propilenoglicóis/metabolismo , Propilenoglicóis/químicaRESUMO
Two structures of fructose 6-phosphate aldolase, the wild-type and an engineered variant containing five active-site mutations, have been solved by cryoelectron microscopy (cryo-EM). The engineered variant affords production of aldols from aryl substituted ketones and aldehydes. This structure was solved to a resolution of 3.1 Å and contains the critical iminium reaction intermediate trapped in the active site. This provides new information that rationalizes the acquired substrate scope and aids in formulating hypotheses of the chemical mechanism. A Tyr residue (Y131) is positioned for a role as catalytic acid/base during the aldol reaction and the different structures demonstrate mobility of this amino acid residue. Further engineering of this fructose 6-phosphate aldolase (FSA) variant, guided by this new structure, identified additional FSA variants that display improved carboligation activities with 2-hydroxyacetophenone and phenylacetaldehyde.
Assuntos
Aldeídos , Domínio Catalítico , Frutose-Bifosfato Aldolase , Cetonas , Engenharia de Proteínas , Aldeídos/química , Aldeídos/metabolismo , Cetonas/química , Cetonas/metabolismo , Frutose-Bifosfato Aldolase/química , Frutose-Bifosfato Aldolase/metabolismo , Frutose-Bifosfato Aldolase/genética , Modelos Moleculares , Microscopia Crioeletrônica , Especificidade por Substrato , Iminas/química , Iminas/metabolismo , Ligação Proteica , Acetaldeído/química , Acetaldeído/metabolismo , Acetaldeído/análogos & derivados , Tirosina/química , Tirosina/metabolismo , Aldeído Liases , Proteínas de Escherichia coliRESUMO
Cancer cellular heterogeneity and therapy resistance arise substantially from metabolic and transcriptional adaptations, but how these are interconnected is poorly understood. Here, we show that, in melanoma, the cancer stem cell marker aldehyde dehydrogenase 1A3 (ALDH1A3) forms an enzymatic partnership with acetyl-coenzyme A (CoA) synthetase 2 (ACSS2) in the nucleus to couple high glucose metabolic flux with acetyl-histone H3 modification of neural crest (NC) lineage and glucose metabolism genes. Importantly, we show that acetaldehyde is a metabolite source for acetyl-histone H3 modification in an ALDH1A3-dependent manner, providing a physiologic function for this highly volatile and toxic metabolite. In a zebrafish melanoma residual disease model, an ALDH1-high subpopulation emerges following BRAF inhibitor treatment, and targeting these with an ALDH1 suicide inhibitor, nifuroxazide, delays or prevents BRAF inhibitor drug-resistant relapse. Our work reveals that the ALDH1A3-ACSS2 couple directly coordinates nuclear acetaldehyde-acetyl-CoA metabolism with specific chromatin-based gene regulation and represents a potential therapeutic vulnerability in melanoma.
Assuntos
Acetaldeído , Melanoma , Peixe-Zebra , Melanoma/metabolismo , Melanoma/genética , Melanoma/patologia , Melanoma/tratamento farmacológico , Acetaldeído/metabolismo , Acetaldeído/farmacologia , Animais , Humanos , Linhagem Celular Tumoral , Aldeído Oxirredutases/metabolismo , Aldeído Oxirredutases/genética , Histonas/metabolismo , Coenzima A Ligases/metabolismo , Coenzima A Ligases/genética , Transcrição Gênica/efeitos dos fármacos , Crista Neural/metabolismo , Crista Neural/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacosRESUMO
Protective effect of quercetin against acetaldehyde was evaluated using the cultured hepatocyte models with aldehyde dehydrogenase (ALDH) isozyme deficiency (aldh2-kd and aldh1a1-kd). The quercetin-induced cytoprotection against acetaldehyde in the ALDH1A1-deficient mutant (aldh1a1-kd) was weaker than that in the wild type. Furthermore, quercetin did not enhance the ALDH activity in aldh1a1-kd cells, suggesting that ALDH1A1 is involved in quercetin-induced cytoprotection.
Assuntos
Acetaldeído , Aldeído Desidrogenase , Hepatócitos , Isoenzimas , Quercetina , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Quercetina/farmacologia , Acetaldeído/farmacologia , Acetaldeído/metabolismo , Animais , Aldeído Desidrogenase/metabolismo , Aldeído Desidrogenase/genética , Aldeído Desidrogenase/deficiência , Isoenzimas/metabolismo , Isoenzimas/genética , Citoproteção/efeitos dos fármacos , Células Cultivadas , CamundongosRESUMO
Golden apple snail (Pomacea canaliculata), a major alien invasive organism in China, affects food production and poses a threat to human health. Metaldehyde is a highly effective, commonly used snail killer with low toxicity. Virulence determination, tissue section, iTRAQ and RNA interference were used to systematically study the toxicity of metaldehyde on P. canaliculata. The molluscicidal activity tests showed that metaldehyde exhibits strong toxicity against P. canaliculata. Physiological and biochemical data indicate that metaldehyde can cause damage to the gills, liver, pancreas, and kidneys of snails, also reduce the oxygen consumption rate and ammonia excretion rate of golden apple snails, and cause neurological diseases. The proteome of the gill region of the golden apple snail after exposure to metaldehyde was analyzed by using iTRAQ technology. A total of 360 differential proteins were identified, and four target proteins were screened, namely, alpha-protein kinase 1 (ALPK1), cubilin (CUBN), sodium- and chloride-dependent GABA transporter 2 (GAT2), and acetylcholinesterase (AChE). RNAi was used to target the four proteins. After the ALPK1 and CUBN protein genes were interfered with by metaldehyde treatment, it was found that the mortality rate of the golden apple snail significantly increased. However, interference of GAT2 and AChE protein genes by metaldehyde led to no significant change in the mortality rates of the snails. The histopathological observation of the gill showed that the rate of cilia shedding in the gill decreased after the interference of ALPK1 and CUBN protein genes.
Assuntos
Moluscocidas , Caramujos , Animais , Caramujos/genética , Caramujos/metabolismo , Moluscocidas/metabolismo , Acetaldeído/análogos & derivados , Acetaldeído/metabolismo , Acetaldeído/toxicidade , Brânquias/metabolismo , Brânquias/efeitos dos fármacos , Acetilcolinesterase/metabolismo , Acetilcolinesterase/genética , ChinaRESUMO
Microdialysis is an important technique for in vivo sampling of tissue's biochemical composition. Understanding the factors that affect the performance of the microdialysis probes and developing methods for sample analysis are crucial for obtaining reliable results. In this work, we used experimental and numerical procedures to study the performance of microdialysis probes having different configurations, membrane materials and dimensions. For alcohol research, it is important to understand the dynamics of ethanol metabolism, particularly in the brain and in other organs, and to simultaneously measure the concentrations of ethanol and its metabolites - acetaldehyde and acetate. Our work provides a comprehensive characterization of three microdialysis probes, in terms of recovery rates and backpressure, allowing for interpretation and optimization of experimental procedures. In vivo experiments were performed to measure the time course concentration of ethanol, acetaldehyde, and acetate in the rat brain dialysate. Additionally, the combination of in vitro experimental results with numerical simulations enabled us to calculate diffusion coefficients of molecules in the microdialysis membranes and study the extent of the depletion effect caused by continuous microdialysis sampling, thus providing additional insights for probe selection and data interpretation.
Assuntos
Encéfalo , Etanol , Microdiálise , Microdiálise/métodos , Etanol/metabolismo , Etanol/análise , Etanol/farmacocinética , Animais , Ratos , Encéfalo/metabolismo , Acetaldeído/análise , Acetaldeído/metabolismo , Masculino , Acetatos/metabolismo , Acetatos/farmacocinéticaRESUMO
Alcohol use disorder (AUD) affects millions of people worldwide, causing extensive morbidity and mortality with limited pharmacological treatments. The liver is considered as the principal site for the detoxification of ethanol metabolite, acetaldehyde (AcH), by aldehyde dehydrogenase 2 (ALDH2) and as a target for AUD treatment, however, our recent data indicate that the liver only plays a partial role in clearing systemic AcH. Here we show that a liver-gut axis, rather than liver alone, synergistically drives systemic AcH clearance and voluntary alcohol drinking. Mechanistically, we find that after ethanol intake, a substantial proportion of AcH generated in the liver is excreted via the bile into the gastrointestinal tract where AcH is further metabolized by gut ALDH2. Modulating bile flow significantly affects serum AcH level and drinking behaviour. Thus, combined targeting of liver and gut ALDH2, and manipulation of bile flow and secretion are potential therapeutic strategies to treat AUD.
Assuntos
Consumo de Bebidas Alcoólicas , Aldeído-Desidrogenase Mitocondrial , Etanol , Fígado , Fígado/metabolismo , Animais , Etanol/metabolismo , Aldeído-Desidrogenase Mitocondrial/metabolismo , Camundongos , Consumo de Bebidas Alcoólicas/metabolismo , Acetaldeído/metabolismo , Inativação Metabólica , Trato Gastrointestinal/metabolismo , Alcoolismo/metabolismo , Humanos , Camundongos Endogâmicos C57BL , Masculino , Microbioma Gastrointestinal , Bile/metabolismoRESUMO
ß-Hydroxy-α-amino acids (ßHAAs) are an essential class of building blocks of therapeutically important compounds and complex natural products. They contain two chiral centers at Cα and Cß positions, resulting in four possible diastereoisomers. Many innovative asymmetric syntheses have been developed to access structurally diverse ßHAAs. The main challenge, however, is the control of the relative and absolute stereochemistry of the asymmetric carbons in a sustainable way. In this respect, there has been considerable attention focused on the chemoenzymatic synthesis of ßHAAs via a one-step process. Nature has evolved different enzymatic routes to produce these valuable ßHAAs. Among these naturally occurring transformations, L-threonine transaldolases present potential biocatalysts to generate ßHAAs in situ. 4-Fluorothreonine transaldolase from Streptomyces sp. MA37 (FTaseMA) catalyzes the cross-over transaldolation reaction between L-Thr and fluoroacetaldehyde to give 4-fluorothreonine and acetaldehyde (Ad). It has been demonstrated that FTaseMA displays considerable substrate plasticity toward structurally diverse aldehyde acceptors, leading to the production of various ßHAAs. In this chapter, we describe methods for the preparation of FTaseMA, and the chemoenzymatic synthesis of ßHAAs from various aldehydes and L-Thr using FTaseMA.
Assuntos
Streptomyces , Transaldolase , Streptomyces/enzimologia , Transaldolase/metabolismo , Transaldolase/química , Transaldolase/genética , Treonina/análogos & derivados , Treonina/química , Treonina/metabolismo , Biocatálise , Aminoácidos/química , Aminoácidos/metabolismo , Especificidade por Substrato , Acetaldeído/análogos & derivados , Acetaldeído/metabolismo , Acetaldeído/química , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Ensaios Enzimáticos/métodos , EstereoisomerismoRESUMO
Histidine residues 44 and 48 in yeast alcohol dehydrogenase (ADH) bind to the coenzymes NAD(H) and contribute to catalysis. The individual H44R and H48Q substitutions alter the kinetics and pH dependencies, and now the roles of other ionizable groups in the enzyme were studied in the doubly substituted H44R/H48Q ADH. The substitutions make the enzyme more resistant to inactivation by diethyl pyrocarbonate, modestly improve affinity for coenzymes, and substantially decrease catalytic efficiencies for ethanol oxidation and acetaldehyde reduction. The pH dependencies for several kinetic parameters are shifted from pK values for wild-type ADH of 7.3-8.1 to values for H44R/H48Q ADH of 8.0-9.6, and are assigned to the water or alcohol bound to the catalytic zinc. It appears that the rate of binding of NAD+ is electrostatically favored with zinc-hydroxide whereas binding of NADH is faster with neutral zinc-water. The pH dependencies of catalytic efficiencies (V/EtKm) for ethanol oxidation and acetaldehyde reduction are similarly controlled by deprotonation and protonation, respectively. The substitutions make an enzyme that resembles the homologous horse liver H51Q ADH, which has Arg-47 and Gln-51 and exhibits similar pK values. In the wild-type ADHs, it appears that His-48 (or His-51) in the proton relay systems linked to the catalytic zinc ligands modulate catalytic efficiencies.
Assuntos
Álcool Desidrogenase , Domínio Catalítico , Histidina , Saccharomyces cerevisiae , Acetaldeído/metabolismo , Acetaldeído/química , Álcool Desidrogenase/metabolismo , Álcool Desidrogenase/genética , Álcool Desidrogenase/química , Substituição de Aminoácidos , Dietil Pirocarbonato/química , Dietil Pirocarbonato/farmacologia , Etanol/metabolismo , Histidina/metabolismo , Histidina/química , Concentração de Íons de Hidrogênio , Cinética , NAD/metabolismo , Oxirredução , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/enzimologia , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Zinco/metabolismo , Zinco/químicaRESUMO
Tuta absoluta ("leafminer"), is a major pest of tomato crops worldwide. Controlling this insect is difficult due to its efficient infestation, rapid proliferation, and resilience to changing weather conditions. Furthermore, chemical pesticides have only a short-term effect due to rapid development of T. absoluta strains. Here, we show that a variety of tomato cultivars, treated with external phenylalanine solutions exhibit high resistance to T. absoluta, under both greenhouse and open field conditions, at different locations. A large-scale metabolomic study revealed that tomato leaves absorb and metabolize externally given Phe efficiently, resulting in a change in their volatile profile, and repellence of T. absoluta moths. The change in the volatile profile is due to an increase in three phenylalanine-derived benzenoid phenylpropanoid volatiles (BPVs), benzaldehyde, phenylacetaldehyde, and 2-phenylethanol. This treatment had no effect on terpenes and green leaf volatiles, known to contribute to the fight against insects. Phe-treated plants also increased the resistance of neighboring non-treated plants. RNAseq analysis of the neighboring non-treated plants revealed an exclusive upregulation of genes, with enrichment of genes related to the plant immune response system. Exposure of tomato plants to either benzaldehyde, phenylacetaldehyde, or 2-phenylethanol, resulted in induction of genes related to the plant immune system that were also induced due to neighboring Phe-treated plants. We suggest a novel role of phenylalanine-derived BPVs as mediators of plant-insect interactions, acting as inducers of the plant defense mechanisms.
Assuntos
Fenilalanina , Folhas de Planta , Solanum lycopersicum , Compostos Orgânicos Voláteis , Solanum lycopersicum/genética , Solanum lycopersicum/metabolismo , Solanum lycopersicum/parasitologia , Fenilalanina/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Animais , Folhas de Planta/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/parasitologia , Benzaldeídos/metabolismo , Benzaldeídos/farmacologia , Acetaldeído/análogos & derivados , Acetaldeído/metabolismo , Acetaldeído/farmacologia , Mariposas/fisiologia , Mariposas/efeitos dos fármacos , Doenças das Plantas/parasitologia , Doenças das Plantas/imunologia , Manduca/fisiologiaRESUMO
Acetaldehyde (AL), a primary carcinogen, not only pollutes the environment, but also endangers human health after drinking alcohol. Here a promising bacterial strain was successfully isolated from a white wine cellar pool in the province of Shandong, China, and identified as Bacillus velezensis-YW01 with 16 S rDNA sequence. Using AL as sole carbon source, initial AL of 1 g/L could be completely biodegraded by YW01 within 84 h and the cell-free extracts of YW01 has also been detected to biodegrade the AL, which indicate that YW01 is a high-potential strain for the biodegradation of AL. The optimal culture conditions and the biodegradation of AL of YW01 are at pH 7.0 and 38 °C, respectively. To further analyze the biodegradation mechanism of AL, the whole genome of YW01 was sequenced. Genes ORF1040, ORF1814 and ORF0127 were revealed in KEGG, which encode for acetaldehyde dehydrogenase. Furthermore, ORF0881 and ORF052 encode for ethanol dehydrogenase. This work provides valuable information for exploring metabolic pathway of converting ethanol to AL and subsequently converting AL to carboxylic acid compounds, which opened up potential pathways for the development of microbial catalyst against AL.
Assuntos
Acetaldeído , Bacillus , Biodegradação Ambiental , Genoma Bacteriano , Bacillus/genética , Bacillus/metabolismo , Acetaldeído/metabolismo , FilogeniaRESUMO
Pseudomonas putida is a soil bacterium with multiple uses in fermentation and biotransformation processes. P. putida ATCC 12633 can biotransform benzaldehyde and other aldehydes into valuable α-hydroxyketones, such as (S)-2-hydroxypropiophenone. However, poor tolerance of this strain toward chaotropic aldehydes hampers efficient biotransformation processes. To circumvent this problem, we expressed the gene encoding the global regulator PprI from Deinococcus radiodurans, an inducer of pleiotropic proteins promoting DNA repair, in P. putida. Fine-tuned gene expression was achieved using an expression plasmid under the control of the LacIQ /Ptrc system, and the cross-protective role of PprI was assessed against multiple stress treatments. Moreover, the stress-tolerant P. putida strain was tested for 2-hydroxypropiophenone production using whole resting cells in the presence of relevant aldehyde substrates. P. putida cells harbouring the global transcriptional regulator exhibited high tolerance toward benzaldehyde, acetaldehyde, ethanol, butanol, NaCl, H2 O2 and thermal stress, thereby reflecting the multistress protection profile conferred by PprI. Additionally, the engineered cells converted aldehydes to 2-hydroxypropiophenone more efficiently than the parental P. putida strain. 2-Hydroxypropiophenone concentration reached 1.6 g L-1 upon a 3-h incubation under optimized conditions, at a cell concentration of 0.033 g wet cell weight mL-1 in the presence of 20 mM benzaldehyde and 600 mM acetaldehyde. Product yield and productivity were 0.74 g 2-HPP g-1 benzaldehyde and 0.089 g 2-HPP g cell dry weight-1 h-1 , respectively, 35% higher than the control experiments. Taken together, these results demonstrate that introducing PprI from D. radiodurans enhances chaotrope tolerance and 2-HPP production in P. putida ATCC 12633.
Assuntos
Deinococcus , Hidroxipropiofenona , Pseudomonas putida , Benzaldeídos/metabolismo , Pseudomonas putida/genética , Pseudomonas putida/metabolismo , Deinococcus/genética , Acetaldeído/metabolismoRESUMO
The alcohol metabolite acetaldehyde is a potent human carcinogen linked to esophageal squamous cell carcinoma (ESCC) initiation and development. Aldehyde dehydrogenase 2 (ALDH2) is the primary enzyme that detoxifies acetaldehyde in the mitochondria. Acetaldehyde accumulation causes genotoxic stress in cells expressing the dysfunctional ALDH2E487K dominant negative mutant protein linked to ALDH2*2, the single nucleotide polymorphism highly prevalent among East Asians. Heterozygous ALDH2*2 increases the risk for the development of ESCC and other alcohol-related cancers. Despite its prevalence and link to malignant transformation, how ALDH2 dysfunction influences ESCC pathobiology is incompletely understood. Herein, we characterize how ESCC and preneoplastic cells respond to alcohol exposure using cell lines, three-dimensional organoids and xenograft models. We find that alcohol exposure and ALDH2*2 cooperate to increase putative ESCC cancer stem cells with high CD44 expression (CD44H cells) linked to tumor initiation, repopulation and therapy resistance. Concurrently, ALHD2*2 augmented alcohol-induced reactive oxygen species and DNA damage to promote apoptosis in the non-CD44H cell population. Pharmacological activation of ALDH2 by Alda-1 inhibits this phenotype, suggesting that acetaldehyde is the primary driver of these changes. Additionally, we find that Aldh2 dysfunction affects the response to cisplatin, a chemotherapeutic commonly used for the treatment of ESCC. Aldh2 dysfunction facilitated enrichment of CD44H cells following cisplatin-induced oxidative stress and cell death in murine organoids, highlighting a potential mechanism driving cisplatin resistance. Together, these data provide evidence that ALDH2 dysfunction accelerates ESCC pathogenesis through enrichment of CD44H cells in response to genotoxic stressors such as environmental carcinogens and chemotherapeutic agents.
Assuntos
Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Humanos , Camundongos , Animais , Carcinoma de Células Escamosas do Esôfago/genética , Aldeído Desidrogenase/genética , Aldeído Desidrogenase/metabolismo , Neoplasias Esofágicas/patologia , Fatores de Risco , Consumo de Bebidas Alcoólicas/genética , Cisplatino/farmacologia , Aldeído-Desidrogenase Mitocondrial/genética , Etanol/metabolismo , Acetaldeído/metabolismo , Transformação Celular Neoplásica , Células-Tronco Neoplásicas/patologia , Álcool Desidrogenase/genéticaRESUMO
Ethanol metabolism plays an essential role in how the body perceives and experiences alcohol consumption, and evidence suggests that modulation of ethanol metabolism can alter the risk for alcohol use disorder (AUD). In this review, we explore how ethanol metabolism, mainly via alcohol dehydrogenase and aldehyde dehydrogenase 2 (ALDH2), contributes to drinking behaviors by integrating preclinical and clinical findings. We discuss how alcohol dehydrogenase and ALDH2 polymorphisms change the risk for AUD, and whether we can harness that knowledge to design interventions for AUD that alter ethanol metabolism. We detail the use of disulfiram, RNAi strategies, and kudzu/isoflavones to inhibit ALDH2 and increase acetaldehyde, ideally leading to decreases in drinking behavior. In addition, we cover recent preclinical evidence suggesting that strategies other than increasing acetaldehyde-mediated aversion can decrease ethanol consumption, providing other potential metabolism-centric therapeutic targets. However, modulating ethanol metabolism has inherent risks, and we point out some of the key areas in which more data are needed to mitigate these potential adverse effects. Finally, we present our opinions on the future of treating AUD by the modulation of ethanol metabolism.
Assuntos
Alcoolismo , Humanos , Alcoolismo/tratamento farmacológico , Alcoolismo/metabolismo , Etanol/efeitos adversos , Aldeído-Desidrogenase Mitocondrial/genética , Aldeído Desidrogenase/metabolismo , Álcool Desidrogenase , Consumo de Bebidas Alcoólicas/efeitos adversos , Acetaldeído/metabolismoRESUMO
The breakdown of ethanol, the active chemical in alcohol, is tightly regulated by the body, yet alcohol intoxication occurs in thousands of Americans annually. Many factors contribute to the concentration of ethanol in the bloodstream and the tolerance an individual has, including body size, previous drinking experience, and liver functionality. We propose a model that estimates both the blood alcohol concentration and the concentration of acetaldehyde (the toxic intermediate during catabolism) in the liver over time to quantify organ damage for an average person. From the current literature, we derived ordinary differential equations that govern the absorption of ethanol in the body and extended it with the metabolic enzyme mechanisms. We also altered the parameters of our system in order to show the effects of Asian flush, which impairs the body's processing of acetaldehyde. We demonstrated the accumulation of acetaldehyde in Asian flush patients was about 660 times higher compared to those without the disease.Clinical relevance-With further improvements and personalization, our model would be able to quantitatively describe the effects of alcohol consumption without having volunteers go through repetitive trials with extensive exposure to alcohol. Liver damage can also be estimated with the acetaldehyde buildup predicted by the model.
Assuntos
Intoxicação Alcoólica , Concentração Alcoólica no Sangue , Humanos , Etanol/metabolismo , Acetaldeído/metabolismo , FígadoRESUMO
Indigenous Saccharomyces cerevisiae strains and their combinations may be used to diversify wines and add complexity to sensory profiles. Here, two S. cerevisiae strains that represent regional genetic and phenotypic specificities for two major winegrowing areas of Greece were used in single- and mixed-culture fermentations. The kinetics and metabolic activities of the strains were analyzed to evaluate the influence of each strain individually or in combination on wine quality. The two strains differentially affected the kinetics and the outcome of fermentation. They showed significant differences in the production of important metabolites that strongly affect the organoleptic profile of wines, such as volatile acidity, acetaldehyde, certain esters, and terpenes. Furthermore, the chemical and sensory profiles of wines produced by single cultures were different from those fermented by mixed-culture inoculum. The concentration of certain metabolites was enhanced (e.g. isoamyl acetate, 1-heptanol), while others were suppressed (e.g. hexyl acetate, octyl acetate). Results highlight the potential worth of indigenous S. cerevisiae strains to differentiate local wines. The mixed-culture S. cerevisiae inoculum was shown to generate novel wine characteristics, as compared to single cultures, thus offering alternatives to further diversify wines and increase their complexity.
Assuntos
Vitis , Vinho , Saccharomyces cerevisiae/metabolismo , Vinho/análise , Fermentação , Acetaldeído/metabolismo , GréciaRESUMO
Autoantibodies to malondialdehyde (MDA) proteins constitute a subset of anti-modified protein autoantibodies in rheumatoid arthritis (RA), which is distinct from citrulline reactivity. Serum anti-MDA IgG levels are commonly elevated in RA and correlate with disease activity, CRP, IL6, and TNF-α. MDA is an oxidation-associated reactive aldehyde that together with acetaldehyde mediates formation of various immunogenic amino acid adducts including linear MDA-lysine, fluorescent malondialdehyde acetaldehyde (MAA)-lysine, and intramolecular cross-linking. We used single-cell cloning, generation of recombinant antibodies (n = 356 from 25 donors), and antigen-screening to investigate the presence of class-switched MDA/MAA+ B cells in RA synovium, bone marrow, and bronchoalveolar lavage. Anti-MDA/MAA+ B cells were found in bone marrow plasma cells of late disease and in the lung of both early disease and risk-individuals and in different B cell subsets (memory, double negative B cells). These were compared with previously identified anti-MDA/MAA from synovial memory and plasma cells. Seven out of eight clones carried somatic hypermutations and all bound MDA/MAA-lysine independently of protein backbone. However, clones with somatic hypermutations targeted MAA cross-linked structures rather than MDA- or MAA-hapten, while the germline-encoded synovial clone instead bound linear MDA-lysine in proteins and peptides. Binding patterns were maintained in germline converted clones. Affinity purification of polyclonal anti-MDA/MAA from patient serum revealed higher proportion of anti-MAA versus anti-MDA compared to healthy controls. In conclusion, IgG anti-MDA/MAA show distinct targeting of different molecular structures. Anti-MAA IgG has been shown to promote bone loss and osteoclastogenesis in vivo and may contribute to RA pathogenesis.
Assuntos
Artrite Reumatoide , Linfócitos B , Humanos , Acetaldeído/metabolismo , Artrite Reumatoide/imunologia , Artrite Reumatoide/patologia , Autoanticorpos , Medula Óssea/metabolismo , Imunoglobulina G/metabolismo , Pulmão/metabolismo , Lisina/metabolismo , Malondialdeído/metabolismo , Linfócitos B/imunologia , Linfócitos B/patologia , AutoimunidadeRESUMO
Alcohol contributes to cellular accumulation of acetaldehyde, a primary metabolite of alcohol and a major human carcinogen. Acetaldehyde can form DNA adducts and induce interstrand crosslinks (ICLs) that are repaired by the Fanconi anemia DNA repair pathway (FA pathway). Individuals with deficiency in acetaldehyde detoxification or in the FA pathway have an increased risk of squamous-cell carcinomas (SCCs) including those of the esophagus. In a recent report, we described the molecular basis of acetaldehyde-induced DNA damage in esophageal keratinocytes [1]. We demonstrated that, at physiologically relevant concentrations, acetaldehyde induces DNA damage at the DNA replication fork. This resulted in replication stress, leading to activation of the ATR-Chk1-dependent cell cycle checkpoints. We also reported that the p53 DNA damage response is elevated in response to acetaldehyde and that the FA pathway limits acetaldehyde-induced genomic instability. Here, we highlight these findings and present additional results to discuss the role of the FA pathway and p53 DNA damage response in the protection against genomic instability and esophageal carcinogenesis.