Aldehyde Dehydrogenase Activity Research Articles

Cholesterol Biosynthesis Inhibitor RO 48-8071 Suppresses Growth of Epithelial Ovarian Cancer Cells in Vitro and In Vivo.

Epithelial Ovarian Cancer (EOC) cells express enzymes in the cholesterol biosynthetic pathway, making this pathway an attractive therapeutic target for controlling ovarian cancer. Potent small molecule inhibitors of one biosynthetic enzyme, Oxidosqualene Cyclase (OSC), have been identified, and RO 48-8071 (4'-[6-(allylmethylamino)hexyloxy]-4-bromo-2'-fluorobenzophenone fumarate) (RO), has emerged as a useful chemotherapeutic agent for breast and prostate cancer. Cell viability assays were performed to determine effects of RO 48-8071 on growth of EOC cells. Aldehyde Dehydrogenase (ALDH) assay was conducted to determine the effects of drug on reducing stem cell like properties of EOC cells. Finally, xenograft studies were performed to assess the ability of RO 48-8071 to inhibit the growth of EOC cells in vivo. We found that short-term (24-48 h) administration of pharmacological doses of RO effectively reduced the viability of drug-resistant EOC cells (SK-OV-3 and OVCAR-3), as determined with sulforhodamine B colorimetric assays. In 7-day assays, nanomolar concentrations of RO effectively inhibited the growth of EOC cells. RO also suppressed ALDH activity, a marker of stem cells. Importantly, RO significantly suppressed growth of xenografts derived from EOC cells when given to mice intraperitoneally (20-40 mg kg-1 day-1) for 27 days once tumors reached 100 mm3 (controls: 336 + 60 mm3; treated: 171 + 20 mm3) with no toxicity to the experimental animals. Mechanistically, RO induced apoptosis in tumor cells in vivo as shown with immunohistochemistry. Cholesterol biosynthesis inhibitor RO 48-8071 is thus a novel and potent inhibitor of human EOC, including EOC stem cells.

Unbalance between Pyridine Nucleotide Cofactors in The SOD1 Deficient Yeast Saccharomyces cerevisiae Causes Hypersensitivity to Alcohols and Aldehydes.

Alcohol and aldehyde dehydrogenases are especially relevant enzymes involved in metabolic and detoxification reactions that occur in living cells. The comparison between the gene expression, protein content, and enzymatic activities of cytosolic alcohol and aldehyde dehydrogenases of the wild-type strain and the Δsod1 mutant lacking superoxide dismutase 1, which is hypersensitive to alcohols and aldehydes, shows that the activity of these enzymes is significantly higher in the Δsod1 mutant, but this is not a mere consequence of differences in the enzymatic protein content nor in the expression levels of genes. The analysis of the NAD(H) and NADP(H) content showed that the higher activity of alcohol and aldehyde dehydrogenases in the Δsod1 mutant could be a result of the increased availability of pyridine nucleotide cofactors. The higher level of NAD+ in the Δsod1 mutant is not related to the higher level of tryptophan; in turn, a higher generation of NADPH is associated with the upregulation of the pentose phosphate pathway. It is concluded that the increased sensitivity of the Δsod1 mutant to alcohols and aldehydes is not only a result of the disorder of redox homeostasis caused by the induction of oxidative stress but also a consequence of the unbalance between pyridine nucleotide cofactors.

ALDH2 attenuates ischemia and reperfusion injury through regulation of mitochondrial fusion and fission by PI3K/AKT/mTOR pathway in diabetic cardiomyopathy

The function of mitochondrial fusion and fission is one of the important factors causing ischemia-reperfusion (I/R) injury in diabetic myocardium. Aldehyde dehydrogenase 2 (ALDH2) is abundantly expressed in heart, which involved in the regulation of cellular energy metabolism and stress response. However, the mechanism of ALDH2 regulating mitochondrial fusion and fission in diabetic myocardial I/R injury has not been elucidated. In the present study, we found that the expression of ALDH2 was downregulated in rat diabetic myocardial I/R model. Functionally, the activation of ALDH2 resulted in the improvement of cardiac hemodynamic parameters and myocardial injury, which were abolished by the treatment of Daidzin, a specific inhibitor of ALDH2. In H9C2 cardiomyocyte hypoxia-reoxygenation model, ALDH2 regulated the dynamic balance of mitochondrial fusion and fission and maintained mitochondrial morphology stability. Meanwhile, ALDH2 reduced mitochondrial ROS levels, and apoptotic protein expression in cardiomyocytes, which was associated with the upregulation of phosphorylation (p-PI3KTyr458, p-AKTSer473, p-mTOR). Moreover, ALDH2 suppressed the mitoPTP opening through reducing 4-HNE. Therefore, our results demonstrated that ALDH2 alleviated the ischemia and reperfusion injury in diabetic cardiomyopathy through inhibition of mitoPTP opening and activation of PI3K/AKT/mTOR pathway.

An Assessment of the Serum Activity of ADH and ALDH in Patients with Primary Biliary Cholangitis

Primary biliary cholangitis (PBC; previously known as primary biliary cirrhosis) is a chronic inflammation-induced cholestatic process in the liver. Antimitochondrial antibodies (AMAs) are observed in around 90% of patients, which suggests that PBC is an autoimmune disease. Alcohol dehydrogenase (ADH), ADH isoenzymes and aldehyde dehydrogenase (ALDH) are localized in the liver, and they are useful markers of liver dysfunction. In this study, the activity of total ADH, ADH isoenzymes and ALDH was evaluated in the blood serum of patients with PBC. The experimental group comprised 50 PBC patients, both male and female, aged 28–67. The control group consisted of 50 healthy subjects, both male and female, aged 25–65. The serum activity of class I ADH, class II ADH and ALDH was measured by spectrofluorophotometry, whereas total ADH and class III ADH activity was determined by photometry methods. The activity of class I ADH and total ADH was significantly higher in the experimental group than in the control group (p < 0.001). An increase in class I ADH and total ADH activity indicates that the isoenzyme class I ADH is released by compromised liver cells and can be useful diagnostic markers of PBC.

ALDH2 deficiency increases susceptibility to binge alcohol-induced gut leakiness, endotoxemia, and acute liver injury in mice through the gut-liver axis

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is the major enzyme responsible for metabolizing toxic acetaldehyde to acetate and acts as a protective or defensive protein against various disease states associated with alcohol use disorder (AUD), including alcohol-related liver disease (ARLD). We hypothesized that Aldh2-knockout (KO) mice are more susceptible to binge alcohol-mediated liver injury than wild-type (WT) mice through increased oxidative stress, gut leakiness and endotoxemia. Therefore, this study aimed to investigate the protective role of ALDH2 in binge alcohol-induced gut permeability, endotoxemia, and acute inflammatory liver injury by exposing Aldh2-KO or WT mice to a single oral dose of binge alcohol 3.5, 4.0, or 5.0 g/kg. Our findings showed for the first time that ALDH2 deficiency in Aldh2-KO mice increases their sensitivity to binge alcohol-induced oxidative and nitrative stress, enterocyte apoptosis, and nitration of gut tight junction (TJ) and adherent junction (AJ) proteins, leading to their degradation. These resulted in gut leakiness and endotoxemia in Aldh2-KO mice after exposure to a single dose of ethanol even at 3.5 g/kg, while no changes were observed in the corresponding WT mice. The elevated serum endotoxin (lipopolysaccharide, LPS) and bacterial translocation contributed to systemic inflammation, hepatocyte apoptosis, and subsequently acute liver injury through the gut-liver axis. Treatment with Daidzin, an ALDH2 inhibitor, exacerbated ethanol-induced cell permeability and reduced TJ/AJ proteins in T84 human colon cells. These changes were reversed by Alda-1, an ALDH2 activator. Furthermore, CRISPR/Cas9-mediated knockout of ALDH2 in T84 cells increased alcohol-mediated cell damage and paracellular permeability. All these findings demonstrate the critical role of ALDH2 in alcohol-induced epithelial barrier dysfunction and suggest that ALDH2 deficiency or gene mutation in humans is a risk factor for alcohol-mediated gut and liver injury, and that ALDH2 could be an important therapeutic target against alcohol-associated tissue or organ damage.

The Generation of Nitric Oxide from Aldehyde Dehydrogenase-2: The Role of Dietary Nitrates and Their Implication in Cardiovascular Disease Management.

Reduced bioavailability of the nitric oxide (NO) signaling molecule has been associated with the onset of cardiovascular disease. One of the better-known and effective therapies for cardiovascular disorders is the use of organic nitrates, such as glyceryl trinitrate (GTN), which increases the concentration of NO. Unfortunately, chronic use of this therapy can induce a phenomenon known as "nitrate tolerance", which is defined as the loss of hemodynamic effects and a reduction in therapeutic effects. As such, a higher dosage of GTN is required in order to achieve the same vasodilatory and antiplatelet effects. Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is a cardioprotective enzyme that catalyzes the bio-activation of GTN to NO. Nitrate tolerance is accompanied by an increase in oxidative stress, endothelial dysfunction, and sympathetic activation, as well as a loss of the catalytic activity of ALDH2 itself. On the basis of current knowledge, nitrate intake in the diet would guarantee a concentration of NO such as to avoid (or at least reduce) treatment with GTN and the consequent onset of nitrate tolerance in the course of cardiovascular diseases, so as not to make necessary the increase in GTN concentrations and the possible inhibition/alteration of ALDH2, which aggravates the problem of a positive feedback mechanism. Therefore, the purpose of this review is to summarize data relating to the introduction into the diet of some natural products that could assist pharmacological therapy in order to provide the NO necessary to reduce the intake of GTN and the phenomenon of nitrate tolerance and to ensure the correct catalytic activity of ALDH2.

Активність цитозольних ензимів катаболізму ендогенних альдегідів у печінці щурів за умов різної забезпеченості раціону нутрієнтами

The research was conducted to study the activity of aldehyde dehydrogenase (EC 1.2.1.3) and aldehyde reductase (EC 1.1.1.21), the levels of TBA reactive substances and protein carbonyl derivates in the cytosolic fraction of rat liver under the conditions of different dietary sucrose and protein content. The animals were distributed into the 4 experimental groups: group I — animals receiving full-value semi-synthetic feed (control group); group II — animals on a low-protein diet (LPD); III group — animals on a high-sucrose diet (HS); IV group — animals on a low-protein and high-sucrose diet (LPD/HS). It was found that in animals under conditions of dietary protein deficiency, there was a two-fold increase in the levels of TBA reactive substances and protein carbonyl derivates in the liver cytosolic fraction against the absence of changes in the aldehyde reductase and aldehyde dehydrogenase activity. At the same time, in animals on a high-sucrose diet, there was a significant accumulation of the TBA reactive substances and carbonyl derivatives in the liver cytosolic fraction along with a 2–2.5-fold increase in both aldehyde reductase and aldehyde dehydrogenase activity. The maximum accumulation of the products of oxidative damage to proteins and lipids along with the insufficient activation of the enzymes ensuring their catabolism can be considered as one of the possible mechanisms of liver cell damage under conditions of the low-protein/high-sucrose diet. The obtained results open new prospects for future studies of the mechanisms of endogenous aldehydes detoxification and further development of a strategy for the correction of metabolic liver disorders under the conditions of nutrient imbalance.

Loss of ALDH2 aggravates mitochondrial biogenesis disorder in cardiac myocytes induced by TAC

Heart failure is one of the major fatal diseases and mitochondrial biogenesis is an important compensatory mechanism in the process of heart failure. Aldehyde dehydrogenase 2(ALDH2) is an important endogenous cardiac protective factor in mitochondria, but its role in mitochondrial biogenesis of cardiomyocytes remains unknown. In our study, transverse aorta constriction(TAC)-induced heart failure model was established in ALDH2−/− mice and wild-type mice. The cardiac function was examined by echocardiography at 4 weeks after operation. The myocardial tissue was stained by HE. The mitochondria morphology was observed using electron microscope, and the ATP content, Sirt1,PGC-1α and NRF1 expression were measured. Compared with wild-type mice, the cardiac function of ALDH2 −/− mice decreased significantly at 4 weeks after TAC. The proportion of mitochondrial area and mitochondrial crest/mitochondrial ratio decreased in the ALDH2−/− group after TAC. The ATP content decreased in ALDH2 −/− mice at 4 weeks after TAC. In the meantime, the expression of PGC-1α,Sirt 1 and NRF1 decreased in the ALDH2−/− TAC group compared with wild type TAC group.Neonatal rat cardiomyocytes were cultured and stretched. Cardiomyocytes were treated with the activator of ALDH2(Alda-1), Sirt1-SiRNA and PGC-1α-siRNA, respectively. The mitochondrial structure of cardiomyocytes was observed by transmission electron microscopy. The levels of PGC-1α,NRF-1 and Tfam were measured by Western blot.Mitochondrial biogenesis was enhanced in stretch cardiomyocytes treated with Alda-1.When cardiomyocytes were treated with Sirt1-SiRNA or PGC1α-SiRNA, the effect of Alda-1 in promoting mitochondrial biogenesis was attenuated.Therefore, these results suggested that the loss of ALDH2 aggravates mitochondrial biogenesis disorder in cardiac myocytes induced by TAC. Alda-1 could promote mitochondrial biogenesis in stretched cardiomyocytes, and this effect depends on Sirt1/PGC-1α pathway.

Decreased propionyl-CoA metabolism facilitates metabolic reprogramming and promotes hepatocellular carcinoma

Alterations of multiple metabolites characterize distinct features of metabolic reprograming in hepatocellular carcinoma (HCC). However, most metabolites including propionyl-CoA (Pro-CoA) are illusive for their functions in metabolic reprograming and hepatocarcinogenesis. This study aims to dissect how Pro-CoA metabolism affects these processes. TCGA data and HCC samples were used to analyze the ALDH6A1-mediated Pro-CoA metabolism and its correlation with HCC. Multiple metabolites were assayed by targeted mass spectrometry. The function of ALDH6A1-generated Pro-CoA was evaluated by HCC proliferation, migration, xenograft nude mouse model and primary liver cancer mouse models. Nontargeted metabolomic and targeted energy metabolomic analyses followed by multiple biochemical assays were performed to dissect the underlying mechanisms. Decreases in Pro-CoA and its derivative propionyl-L-carnitine (PLC) due to ALDH6A1 downregulation were tightly associated with HCC. Functionally, ALDH6A1-mediated Pro-CoA metabolism suppressed HCC proliferation and impaired hepatocarcinogenesis in mice. The aldehyde dehydrogenase activity was indispensable for the ALDH6A1 function while Pro-CoA carboxylases antagonized ALDH6A1 function by eliminating Pro-CoA. Mechanistically, ALDH6A1 caused a signature enrichment of central carbon metabolism in cancer and impaired energy metabolism: ALDH6A1-generated Pro-CoA suppressed citrate synthase (CS) activity that subsequently reduced TCA cycle flux, impaired mitochondrial respiration and membrane potential, and decreased ATP production. Moreover, Pro-CoA metabolism generated 2-methylcitric acid (MCA), which mimicked the inhibitory effect of Pro-CoA on CS and dampened mitochondrial respiration and HCC proliferation. Our study unveils novel features that the decline of ALDH6A1-mediated Pro-CoA metabolism contributes to metabolic remodeling and facilitates hepatocarcinogenesis. Pro-CoA, PLC and MCA may serve as novel metabolic biomarkers for diagnosis and therapy of HCC. Pro-CoA metabolism may provide potential targets for development of novel strategies against HCC. Our study presents new insights on metabolic reprogramming and hepatocarcinogenesis attribute to the decline of ALDH6A1-mediated propionyl-CoA. These findings may enrich molecular and metabolic indicators for physicians to improve clinical practice. These biomarkers may potentially be used for diagnosis and serve as targets for the development of therapeutic strategies against HCC.

ΔNp63/p73 drive metastatic colonization by controlling a regenerative epithelial stem cell program in quasi-mesenchymal cancer stem cells.

Cancer stem cells (CSCs) may serve as the cellular seeds of tumor recurrence and metastasis, and they can be generated via epithelial-mesenchymal transitions (EMTs). Isolating pure populations of CSCs is difficult because EMT programs generate multiple alternative cell states, and phenotypic plasticity permits frequent interconversions between these states. Here, we used cell-surface expression of integrin β4 (ITGB4) to isolate highly enriched populations of human breast CSCs, and we identified the gene regulatory network operating in ITGB4+ CSCs. Specifically, we identified ΔNp63 and p73, the latter of which transactivates ΔNp63, as centrally important transcriptional regulators of quasi-mesenchymal CSCs that reside in an intermediate EMT state. We found that the transcriptional program controlled by ΔNp63 in CSCs is largely distinct from the one that it orchestrates in normal basal mammary stem cells and, instead, it more closely resembles a regenerative epithelial stem cell response to wounding. Moreover, quasi-mesenchymal CSCs repurpose this program to drive metastatic colonization via autocrine EGFR signaling.

The Loss-of-Function Mutation aldA67 Leads to Enhanced α-L-Rhamnosidase Production by Aspergillus nidulans.

In Aspergillus nidulans L-rhamnose is catabolised to pyruvate and L-lactaldehyde, and the latter ultimately to L-lactate, via the non-phosphorylated pathway (LRA) encoded by the genes lraA-D, and aldA that encodes a broad substrate range aldehyde dehydrogenase (ALDH) that also functions in ethanol utilisation. LRA pathway expression requires both the pathway-specific transcriptional activator RhaR (rhaR is expressed constitutively) and the presence of L-rhamnose. The deletion of lraA severely impairs growth when L-rhamnose is the sole source of carbon and in addition it abolishes the induction of genes that respond to L-rhamnose/RhaR, indicating that an intermediate of the LRA pathway is the physiological inducer likely required to activate RhaR. The loss-of-function mutation aldA67 also has a severe negative impact on growth on L-rhamnose but, in contrast to the deletion of lraA, the expression levels of L-rhamnose/RhaR-responsive genes under inducing conditions are substantially up-regulated and the production of α-L-rhamnosidase activity is greatly increased compared to the aldA+ control. These findings are consistent with accumulation of the physiological inducer as a consequence of the loss of ALDH activity. Our observations suggest that aldA loss-of-function mutants could be biotechnologically relevant candidates for the over-production of α-L-rhamnosidase activity or the expression of heterologous genes driven by RhaR-responsive promoters.

Abstract 15145: Aldehyde Dehydrogenase 2 Agonist Reverses Fibroblast Activation in the End Stage Human Right Ventricle Failure via 3’Utr Regulation of Profibrotic Genes

Background: Cardiac fibrosis, a prominent feature of pressure overloaded right ventricle (RV) in pulmonary hypertension (PH), is fundamental to the development of right ventricle failure (RVF). We found that a defect in alternative polyadenylation (APA) of profibrotic genes is a driving factor that induces fibrosis. Oxidative stress-mediated reactive aldehydes, such as 4-hydroxy-2-nonenal (4HNE) contribute to fibrosis and extracellular matrix (ECM) remodeling. However, the role of 4HNE in APA is unknown. Methods: We compared isolated cardiac fibroblasts from the RVs of explanted transplanted hearts of recipients with pulmonary hypertension patients to control hearts. Results: Compared to controls, tissue and fibroblasts derived from failing RV human hearts have greater deposition of extracellular matrix (ECM) proteins, such as collagen type I alpha (COL1A) and fibronectin (FN1), the expression of alpha smooth muscle actin (α-SMA), indicative of myofibroblast differentiation, and nuclear factor kappa B subunit (NFκB), a transcription factor critical for profibrotic genes transcriptional activation. Moreover, alternative polyadenylation (APA) isoforms of mRNA for COL1A, FN1, NFκB, TGF-β1 and its receptor - transforming growth factor beta receptor 1 (TGFβR1) are associated with shortened 3’UTR in RVF tissues or fibroblasts. Likewise, reduced expression and activity of aldehyde dehydrogenase 2 (ALDH2) expression, a 4HNE detoxifying enzyme, correlated with increased 4HNE adduction in tissues and cardiac fibroblasts derived from RVF hearts. Moreover, ALDH2 activation by its agonist, Alda-1, decreased 4HNE adduction and oxidative stress and most importantly downregulated the gene and protein expression of profibrotic genes, simultaneously lengthening the 3’UTR of the previously shortened profibrotic genes. Conclusion: In RVF, fibroblasts express mRNA of profibrotic genes with shortened 3'UTRs, suggesting the feasibility of developing antifibrotic therapies targeting 3'UTRs in myofibroblasts. Furthermore, our findings suggest that Alda-1 has a therapeutic role in mitigating cardiac fibrosis in RVF hearts by attenuating 4HNE-mediated dysregulation of APA.

Loss of CD24 promotes radiation‑ and chemo‑resistance by inducing stemness properties associated with a hybrid E/M state in breast cancer cells.

Cancer stem cells (CSCs) serve an essential role in failure of conventional antitumor therapy. In breast cancer, CD24‑/low/CD44+ phenotype and high aldehyde dehydrogenase activity are associated with CSC subtypes. Furthermore, CD24‑/low/CD44+ pattern is also characteristic of mesenchymal cells generated by epithelial‑mesenchymal transition (EMT). CD24 is a surface marker expressed in numerous types of tumor, however, its biological functions and role in cancer progression and treatment resistance remain poorly documented. Loss of CD24 expression in breast cancer cells is associated with radiation resistance and control of oxidative stress. Reactive oxygen species (ROS) mediate the effects of anticancer drugs as well as ionizing radiation; therefore, the present study investigated if CD24 mediates radiation‑ and chemo‑resistance of breast cancer cells. Using a HMLE breast cancer cell model, CD24 expression has been artificially modulated and it was observed that loss of CD24 expression induced stemness properties associated with acquisition of a hybrid E/M phenotype. CD24‑/low cells were more radiation‑ and chemo‑resistant than CD24+ cells. The resistance was associated with lower levels of ROS; CD24 controlled ROS levels via regulation of mitochondrial function independently of antioxidant activity. Together, these results suggested a key role of CD24 in de‑differentiation of breast cancer cells and promoting acquisition of therapeutic resistance properties.

Bufalin Inhibits Tumorigenesis, Stemness, and Epithelial-Mesenchymal Transition in Colorectal Cancer through a C-Kit/Slug Signaling Axis.

Colorectal cancer (CRC) is a major source of morbidity and mortality, characterized by intratumoral heterogeneity and the presence of cancer stem cells (CSCs). Bufalin has potent activity against many tumors, but studies of its effect on CRC stemness are limited. We explored bufalin's function and mechanism using CRC patient-derived organoids (PDOs) and cell lines. In CRC cells, bufalin prevented nuclear translocation of β-catenin and down-regulated CSC markers (CD44, CD133, LGR5), pluripotency factors, and epithelial-mesenchymal transition (EMT) markers (N-Cadherin, Slug, ZEB1). Functionally, bufalin inhibited CRC spheroid formation, aldehyde dehydrogenase activity, migration, and invasion. Network analysis identified a C-Kit/Slug signaling axis accounting for bufalin's anti-stemness activity. Bufalin treatment significantly downregulated C-Kit, as predicted. Furthermore, overexpression of C-Kit induced Slug expression, spheroid formation, and bufalin resistance. Similarly, overexpression of Slug resulted in increased expression of C-Kit and identical functional effects, demonstrating a pro-stemness feedback loop. For further study, we established PDOs from diagnostic colonoscopy. Bufalin differentially inhibited PDO growth and proliferation, induced apoptosis, restored E-cadherin, and downregulated CSC markers CD133 and C-Myc, dependent on C-Kit/Slug. These findings suggest that the C-Kit/Slug axis plays a pivotal role in regulating CRC stemness, and reveal that targeting this axis can inhibit CRC growth and progression.

Buyang Huanwu decoction inhibits cardiomyocyte apoptosis after myocardial infarction by enhancing aldehyde dehydrogenase-2 activity and protein expression

ObjectiveTo investigate the potential mechanisms of the protective effects of Buyang Huanwu decoction (BYHWD) on cardiomyocyte apoptosis after myocardial infarction (MI) and to provide the foundation for the clinical application of BYHWD in preventing and treating cardiomyocyte apoptosis-related disorders after MI. MethodsThe MI rat model was established by ligation of the left anterior descending (LAD) coronary artery. After the 20-week treatment with BYHWD, the following parameters were assessed to investigate the protective effects of BYHWD on cardiomyocyte apoptosis after MI, both in vivo and in vitro: mortality rate; heart weight/body weight (HW/BW); transthoracic echocardiography measurements; histopathological analysis; immunohistochemistry (IHC) analysis; TUNEL apoptosis assay; caspase-3 activity assay; aldehyde dehydrogenase-2 (ALDH2) enzymatic activity assay; malondialdehyde (MDA) content analysis; western blot analysis; MTT assay; and Hoechst 33342/PI apoptosis assay. ResultsThe mortality of the MI rats was significantly reduced by BYHWD treatment. Furthermore, BYHWD treatment significantly improved the heart function and significantly reduced the HW/BW ratio. Histopathological analysis showed that BYHWD treatment significantly relieved MI-induced cardiac injury and significantly decreased collagen formation. The TUNEL apoptosis assay showed that treatment with BYHWD reduced the cardiomyocyte apoptosis of MI rats in a dose-dependent manner. Moreover, BYHWD treatment could significantly inhibit oxidative stress-induced neonatal cardiomyocyte apoptosis, which is consistent with the results of animal experiments in vivo. Interestingly, the ALDH2 activity and protein expression was significantly reduced in the MI model group, while the content of toxic aldehydes, including 4-HNE and MDA, was increased. Importantly, BYHWD enhanced the activity of ALDH2 and the expression of ALDH2 protein and attenuated the content of toxic aldehydes in a dose-dependent manner. Furthermore, we found that co-treatment with an ALDH2 inhibitor, disulfiram, partially inhibited the cardiomyocyte protective effects of BYHWD. ConclusionsCollectively, our results suggest that BYHWD exerted anti-apoptotic effects in cardiomyocytes after MI by enhancing the ALDH2 activity and protein expression and decreasing the toxic aldehyde content.

Targeting aldehyde dehydrogenase for prostate cancer therapies.

Prostate cancer (PCa) is the most common cancer in men in the United States. About 10 – 20% of PCa progress to castration-resistant PCa (CRPC), which is accompanied by metastasis and therapeutic resistance. Aldehyde dehydrogenase (ALDH) is famous as a marker of cancer stem-like cells in different cancer types, including PCa. Generally, ALDHs catalyze aldehyde oxidation into less toxic carboxylic acids and give cancers a survival advantage by reducing oxidative stress caused by aldehyde accumulation. In PCa, the expression of ALDHs is associated with a higher tumor stage and more lymph node metastasis. Functionally, increased ALDH activity makes PCa cells gain more capabilities in self-renewal and metastasis and reduces the sensitivity to castration and radiotherapy. Therefore, it is promising to target ALDH or ALDHhigh cells to eradicate PCa. However, challenges remain in moving the ALDH inhibitors to PCa therapy, potentially due to the toxicity of pan-ALDH inhibitors, the redundancy of ALDH isoforms, and the lack of explicit understanding of the metabolic signaling transduction details. For targeting PCa stem-like cells (PCSCs), different regulators have been revealed in ALDHhigh cells to control cell proliferation and tumorigenicity. ALDH rewires essential signaling transduction in PCa cells. It has been shown that ALDHs produce retinoic acid (RA), bind with androgen, and modulate diverse signaling. This review summarizes and discusses the pathways directly modulated by ALDHs, the crucial regulators that control the activities of ALDHhigh PCSCs, and the recent progress of ALDH targeted therapies in PCa. These efforts will provide insight into improving ALDH-targeted treatment.

Phosphodiesterase 4 mRNA Level Suppression is Important for Extract of Black Carrot to Protect Against Hepatic Injury Induced by Ethanol.

Excessive alcohol use often results in alcoholic liver disease (ALD). An early change in the liver due to excessive drinking is hepatic steatosis, which may ultimately progress to hepatitis, liver fibrosis, cirrhosis, and liver cancer. Among these debilitating processes, hepatic steatosis is reversible with the appropriate treatment. Therefore, it is important to find treatments and foods that reverse hepatic steatosis. Black carrot has antioxidant and anti-inflammatory effects. In this study, we examined the effectiveness of black carrot extract (BCE) on hepatic steatosis in in vivo and in vitro ethanol-induced liver injury models. For the in vivo experiments, serum aminotransferase activities enhanced by ethanol- and carbon tetrachloride were significantly suppressed by the BCE diet. Furthermore, morphological changes in the liver hepatic steatosis and fibrosis were observed in the in vivo ethanol-induced liver injury model, however, BCE feeding resulted in the recovery to an almost normal liver morphology. In the in vitro experiments, ethanol treatment induced reactive oxygen species (ROS) levels in hepatocytes at 9 h. Conversely, ROS production was suppressed to control levels and hepatic steatosis was suppressed when hepatocyte culture with ethanol were treated with BCE. Furthermore, we investigated enzyme activities, enzyme protein levels, and messenger RNA levels of alcohol dehydrogenase (ADH), cytochrome p450 2E1 (CYP2E1), and aldehyde dehydrogenase (ALDH) using enzyme assays, western blot, and quantitative reverse transcription-polymerase chain reaction analyses. We found that the activities of ADH, CYP2E1, and ALDH were regulated through the cAMP-PKA pathway at different levels, namely, translational, posttranslational, and transcriptional levels, respectively. The most interesting finding of this study is that BCE increases cAMP levels by suppressing the Pde4b mRNA and PDE4b protein levels in ethanol-treated hepatocytes, suggesting that BCE may prevent ALD.

The microbiota catabolites of quercetin glycosides concertedly enhance the resistance against acetaldehyde-induced oxidative stress

3,4-Dihydroxyphenylacetic acid (DOPAC) and 3-hydroxyphenylacetic acid (OPAC) are the predominant catabolites of quercetin glycosides, such as quercetin 4′-O-β-glucoside from the onion, produced by intestinal microbiota. Although each catabolite has been reported to protect the cells from acetaldehyde-induced cytotoxicity, the effect of their combination remains to be clarified. The purpose of this study was to determine whether the combination of DOPAC and OPAC enhances the resistance against the acetaldehyde-induced oxidative stress in the cultured hepatocytes. The pretreatment of the combination of DOPAC (5 μM) and OPAC (5 μM) showed significant protection against the acetaldehyde- and hydrogen peroxide-induced cytotoxicity, even though each compound at the same concentration did not. This combination also significantly inhibited the intracellular dichlorofluorescin diacetate-detectable reactive oxygen species (ROS) level, whereas the solo treatment did slightly, suggesting that reducing mechanisms of ROS or compounds that enhance ROS production are involved in the cytoprotective effect. The combinatory treatment significantly enhanced the gene expression of not only the aldehyde dehydrogenases (ALDHs), but also glutamate-cysteine ligase, catalytic subunit, the first rate-limiting enzyme of glutathione (GSH) synthesis. Accordingly, both the intracellular GSH level and the total ALDH activity were enhanced by DOPAC plus OPAC. Involvement of GSH in the cytoprotection as well as ALDH up-regulation by the combination was confirmed by the experiments using a GSH biosynthesis inhibitor, buthionine sulfoximine. Taken together, the present results suggested that the quercetin microbiota catabolites concertedly protect the cells from acetaldehyde through a pre-enhanced resistance against oxidative stress by the GSH-dependent up-regulation of ALDHs.

The Association between the ALDH2 rs671 Polymorphism and Athletic Performance in Japanese Power and Strength Athletes.

The rs671 polymorphism is associated with the enzymatic activity of aldehyde dehydrogenase 2 (ALDH2), which is weakened by the A allele in East Asians. We recently reported the association of this polymorphism with the athletic status in athletic cohorts and the muscle strength of non-athletic cohorts. Therefore, we hypothesized the association of ALDH2 rs671 polymorphism with the performance in power/strength athletes. We aimed to clarify the relationship between the ALDH2 rs671 polymorphism and performance in power/strength athletes. Participants comprising 253 power/strength athletes (167 men and 86 women) and 721 healthy controls (303 men and 418 women) were investigated. The power/strength athletes were divided into classic powerlifting (n = 84) and weightlifting (n = 169). No differences in the genotypes and allele frequencies of the ALDH2 rs671 polymorphism and an association between performance and the ALDH2 rs671 genotype were observed in weightlifters. However, the relative values per body weight of the total record were lower in powerlifters with the GA + AA genotype than those with the GG genotype (7.1 ± 1.2 vs. 7.8 ± 1.0; p = 0.010, partial η2 = 0.08). Our results collectively indicate a role of the ALDH2 rs671 polymorphism in strength performance in powerlifters.

ALDA-1 TREATMENT ALLEVIATES LUNG INJURY AFTER CARDIAC ARREST AND RESUSCITATION IN SWINE.

Introduction: Alda-1, an aldehyde dehydrogenase 2 (ALDH2) activator, has been shown to protect the lung against a variety of diseases including regional ischemia-reperfusion injury, severe hemorrhagic shock, hyperoxia, and so on. The present study was designed to investigate the effectiveness of Alda-1 treatment in alleviating lung injury after cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) in swine. Methods: A total of 24 swine were randomized into three groups: sham (n = 6), CA/CPR (n = 10), and CA/CPR + Alda-1 (n = 8). The swine model was established by 8 min of electrically induced and untreated CA, and then 8 min of manual CPR. A dose of 0.88 mg/kg of Alda-1 was intravenously injected at 5 min after CA/CPR. After CA/CPR, extravascular lung water index (ELWI), pulmonary vascular permeability index (PVPI), and oxygenation index (OI) were regularly evaluated for 4 h. At 24 h after resuscitation, lung ALDH2 activity was detected, and its injury score, apoptosis, and ferroptosis were measured. Results: After experiencing the same procedure of CA and CPR, five swine in the CA/CPR group and six swine in the CA/CPR + Alda-1 group restored spontaneous circulation. Subsequently, significantly increased ELWI and PVPI, and markedly decreased OI were observed in these two groups compared with the sham group. However, all of them were gradually improved and significantly better in the swine treated with the Alda-1 compared with the CA/CPR group. Tissue analysis indicated that lung ALDH2 activity was significantly decreased in those swine experiencing the CA/CPR procedure compared with the sham group; nevertheless, its activity was significantly greater in the CA/CPR + Alda-1 group than in the CA/CPR group. In addition, lung injury score, and its apoptosis and ferroptosis were significantly increased in the CA/CPR and CA/CPR + Alda-1 groups compared with the sham group. Likewise, Alda-1 treatment significantly decreased these pathological damages in lung tissue when compared with the CA/CPR group. Conclusions: Alda-1 treatment was effective to alleviate lung injury after CA/CPR in a swine model, in which the protective role was possibly related to the inhibition of cell apoptosis and ferroptosis. It might provide a novel therapeutic target and a feasible therapeutic drug for lung protection after CA/CPR.