Aldehyde Dehydrogenase Activity Research Articles

Aldehyde Dehydrogenase 2 Protects Against Lipopolysaccharide-Induced Myocardial Injury by Suppressing Mitophagy.

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis-induced circulatory and cardiac dysfunction is associated with high mortality rates. Mitophagy, a specific form of autophagy, is excessively activated in lipopolysaccharide-induced myocardial injury. The present study investigated whether aldehyde dehydrogenase 2 (ALDH2) regulates mitophagy in sepsis-induced myocardial dysfunction. After lipopolysaccharide administration, cardiac dysfunction, inflammatory cell infiltration, biochemical indicators of myocardial cell injury, and cardiomyocyte apoptosis were ameliorated in mice by ALDH2 activation or overexpression. In contrast, cardiac dysfunction and cardiomyocyte apoptosis were exacerbated in mice followed ALDH2 inhibition. Moreover, ALDH2 activation or overexpression regulated mitophagy by suppressing the expression of phosphatase and tensin homolog-induced putative kinase 1 (PINK1)/Parkin, by preventing the accumulation of 4-hydroxy-trans-nonenal. Conversely, ALDH2 inhibition promoted the expression of LC3B by increasing 4-hydroxy-trans-2-nonenal accumulation. Consequently, ALDH2 may protect the heart from lipopolysaccharide-induced injury by suppressing PINK1/Parkin-dependent mitophagy.

Overexpression of TNF\u03b1 induces senescence, autophagy and mitochondrial dysfunctions in melanoma cells

BackgroundTumor necrosis factor alpha (TNFα) is a pleiotropic cytokine with both anti-tumorigenic and pro-tumorigenic activity, affecting tumor cell biology, the balance between cell survival and death. The final effect of TNFα is dependent on the type of malignant cells, with the potential to arrest cancer progression.MethodsIn order to explain the diverse cellular response to TNFα, we engineered melanoma and colorectal carcinoma cell lines stably overexpressing this cytokine.ResultsUnder the TNFα overexpression, significant upregulation of two genes was observed: proinflammatory cytokine IL6 gene in melanoma cells A375 and gene for pro-apoptotic ligand TRAIL in colorectal carcinoma cells HT29, both mediated by TNFα/TNFR1 signaling. Malignant melanoma line A375 displayed also increased autophagy on day 3, followed by premature senescence on day 6. Both processes seem to be interconnected, following earlier apoptosis induction and deregulation of mitochondrial functions. We documented altered mitochondrial status, lowered ATP production, lowered mitochondrial mass, and changes in mitochondrial morphology (shortened and condensed mitochondria) both in melanoma and colorectal carcinoma cells. Overexpression of TNFα was not linked with significant affection of the subpopulation of cancer stem-like cells in vitro. However, we could demonstrate a decrease in aldehyde dehydrogenase (ALDH) activity up to 50%, which is associated with to the stemness phenotype.ConclusionsOur in vitro study of direct TNFα influence demonstrates two distinct outcomes in tumor cells of different origin, in non-epithelial malignant melanoma cells of neural crest origin, and in colorectal carcinoma cells derived from the epithelium.

Acetaldehyde within e‐cigarette aerosol and cigarette smoke triggers intracellular calcium release in primary adult cardiomyocytes that is exacerbated in ALDH2*2 mice

Background Cigarette smoke can trigger calcium influx in cardiac myocytes that over time can lead to cardiovascular diseases linked to calcium handling such as atrial fibrillation and heart failure. E-cigarette vapor, similar to cigarette smoke, contains aldehydes that trigger intracellular calcium in neurons. Further, ~560 million people carry an inactivating genetic variant in aldehyde dehydrogenase 2 (ALDH2), known as ALDH2*2, the primary enzyme responsible for metabolizing acetaldehyde. However, little is known how acetaldehyde present in cigarette smoke and e-cigarette aerosol, when coupled with genetics, influence intracellular calcium release within the cardiac myocyte. Hypothesis: Acetaldehyde in e-cigarette aerosol and cigarette smoke can trigger calcium influx in cardiac myocytes. Methods: ALDH2 expression and activity were quantified from wild type ALDH2 and ALDH2*2 male mice heart homogenates. Further, ALDH2 and ALDH2*2 primary adult cardiac myocytes were treated with a short burst of acetaldehyde (0.1-100 μM for 30 seconds, to recapitulate vaping or smoking) and intracellular calcium levels were assessed by fura-2 (5 μM). A Student's t-test was used to compare responses between rodents with significance *p<0.05. Results: The enzymatic activity to metabolize aldehydes within the heart was 3-fold lower for the ALDH2*2 relative to ALDH2 heart homogenates (0.14±0.003* versus 0.45±0.02, ALDH2/GAPDH relative densitometry units, n=3/group). Further, acetaldehyde (0.1 μM) triggered intracellular calcium influx that was 5-fold higher for ALDH2*2 myocytes compared to ALDH2 myocytes (8.32±0.72 %* versus 1.46±0.31%, percent of maximal response, n=4-6 cells from 4 biological replicates). Peak intracellular calcium influx was also ~40% higher for ALDH2*2 myocytes when compared to wild type ALDH2 myocytes over a range of additional acetaldehyde doses (0.1-100 μM) tested. Conclusion: Acetaldehyde, the primary aldehyde in e-cigarette aerosol, triggers intracellular calcium influx that is ~40% greater for rodents carrying an inactivating ALDH2 variant, ALDH2*2. People carrying an inactive ALDH2*2 genetic variant may be more susceptible to acetaldehyde present within e-cigarette vapor and cigarette smoke which over time and continued use lead to developing cardiovascular diseases linked to altered calcium handling.

Acetaldehyde in e‐cigarette aerosol and cigarette smoke exacerbate pulmonary microvascular endothelial dysfunction in ALDH2*2 mice

Background Pulmonary endothelial dysfunction caused by the frequent exposure to cigarette smoke can lead to pulmonary artery hypertension (PAH). E-cigarette vapor, similar to cigarette smoke, contains the aldehydes including acetaldehyde. Further, ~560 million people carry an inactivating genetic variant in aldehyde dehydrogenase 2 (ALDH2), known as ALDH2*2, the primary enzyme responsible for metabolizing acetaldehyde. However, little is known how reactive acetaldehyde present in cigarette smoke and e-cigarette aerosol, when coupled with genetics, influence pulmonary vascular function. Hypothesis: Acetaldehyde in e-cigarette aerosol and cigarette smoke lead to pulmonary endothelial dysfunction that is exacerbated in mice carrying the ALDH2*2 variant. Methods: Primary cultures of pulmonary microvascular endothelial cells from wild type ALDH2 and ALDH2*2 male mice were used. Cultures were treated with acetaldehyde (1 μM for 1 hour) in the presence and absence of the ALDH2 activator, Alda-1 (20 μM). Intracellular ROS accumulation, reactive aldehyde-induced protein adducts, mitochondrial bioenergetics, and endothelial function by capillary tube formation were measured. ANOVA with Bonferroni correction was performed for multiple comparisons between groups. * P<0.05. Results: In ALDH2 and ALDH2*2 mice, no differences were noted in endothelial cell morphology and expression of CD31, an endothelial specific marker. However, when exposed to acetaldehyde, pulmonary microvascular endothelial cells from ALDH2*2 mice showed a 91.2±23.2% increase in 4-HNE-induced protein adducts, a 27.8±5.1% reduction in mitochondrial bioenergetics, a 11.1±1.6% decrease in cell viability, and an 70.4±17.2% exacerbation of endothelial dysfunction compared to wild type ALDH2 cells (p<0.05 for each assay, n=3 biological replicates). Pretreatment with Alda-1 partially reversed the oxidative stress and endothelial injury caused by acetaldehyde treatment. Conclusion: Acetaldehyde, the primary aldehyde present in e-cigarette aerosol which is also in cigarette smoke triggers pulmonary endothelial dysfunction particularly for rodents carrying an inactivating ALDH2 variant, ALDH2*2. This study provides a mechanism how e-cigarette vapor similar to cigarette smoke can trigger endothelial dysfunction that can over time potentially lead to the development of PAH.

Impact of mitochondrial aldehyde dehydrogenase 2 on cognitive impairment in the AD model mouse.

Alzheimer's disease (AD) is one of the major life-threatening diseases for the elderly because neither pathogenesis nor effective treatment is available. Mitochondrial aldehyde dehydrogenase 2 (ALDH2) has been shown to reduce the cell-damaging aldehydes in response to reactive oxygen species (ROS). However, whether it plays a role in AD remains elusive. In the present study, we found that ALDH2 overexpression significantly improved the cognitive function of the AD mouse. Behavioral analyses of ALDH2-overexpressing APP/PS1 AD mice showed that the learning and cognitive abilities were significantly higher in these mice than in the control group APP/PS1 mice. Further open-field behavior experiments showed the same results. At the cellular level, ALDH2 protects nerve cells. HT22 cells were challenged with Aβ to establish an AD cell model, in the presence or absence of the ALDH2 activator Alda-1 and ALDH2 inhibitor Daidzin. Incubation with 50 μM Aβ for 24 h significantly reduced HT22 cell survival and cell viability, the effects of which were attenuated by the ALDH2 activator Alda-1 (50 μM). Aβ challenge promoted apoptosis and upregulated caspase3 level but suppressed Bcl-2 level, and the upregulated caspase3 level was reversed by the ALDH-2 agonist Alda-1. Aβ-induced clonal ball abnormal was reversed by Alda-1. Aβ altered the mitochondria geometry evidenced by vacuolar degeneration and membrane rupture, whereas Alda-1 changed the Aβ-induced mitochondria geometry anomalies. Moreover, superoxide anion and toxic 4-hydroxy-nonanal (4-HNE) and ROS increased by Aβ challenge were reversed by Alda-1. Meanwhile, Aβ-induced ATP reduction was reversed by Alda-1. Taken together, ALDH2 overexpression significantly improves the cognitive function of the AD mice. Furthermore, our results suggested that ALDH2 protects against Aβ hippocampal neuronal toxicity possibly through alleviating toxic aldehydes and ROS, as well as increasing ATP production to preserve mitochondrial integrity and reduce neuronal apoptosis.

Enhancement of Solubility, Purification, and Inclusion Body Refolding of Active Human Mitochondrial Aldehyde Dehydrogenase 2.

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is predominantly linked with acetaldehyde detoxification in the second stage of alcohol metabolism. To intensively study ALDH2 function, a higher purity and uniform composition of the protein is required. An efficient Escherichia coli system for ALDH2 expression was developed by using His and a small ubiquitin-related modifier fusion tag. Most of the recombinant ALDH2s were expressed in the form of inclusion bodies. The ALDH2-enriched inclusion bodies were denatured with 6 M guanidine hydrochloride, and then ALDH2 was ultrafitrated. Finally, ALDH2 was successfully purified through affinity and gel filtration chromatography. The purified ALDH2 was finally preserved by the vacuum freeze-drying method, and its purity was determined to be higher than 95%, with a final media yield of 33.89 mg/L. The specific activity of ALDH2 was 6.1 × 104 U/mg. This work was the first to report pET-SUMO-ALDH2 recombinant plasmid expression in Escherichia coli, and the inclusion bodies were isolated and refolded. Finally, the purified ALDH2 had relatively higher purity, yield, and biological activity.

Post-transcriptional repression of circadian component CLOCK regulates cancer-stemness in murine breast cancer cells.

Disruption of the circadian clock machinery in cancer cells is implicated in tumor malignancy. Studies on cancer therapy reveal the presence of heterogeneous cells, including breast cancer stem-like cells (BCSCs), in breast tumors. BCSCs are often characterized by high aldehyde dehydrogenase (ALDH) activity, associated with the malignancy of cancers. In this study, we demonstrated the negative regulation of ALDH activity by the major circadian component CLOCK in murine breast cancer 4T1 cells. The expression of CLOCK was repressed in high-ALDH-activity 4T1, and enhancement of CLOCK expression abrogated their stemness properties, such as tumorigenicity and invasive potential. Furthermore, reduced expression of CLOCK in high-ALDH-activity 4T1 was post-transcriptionally regulated by microRNA: miR-182. Knockout of miR-182 restored the expression of CLOCK, resulted in preventing tumor growth. Our findings suggest that increased expression of CLOCK in BCSCs by targeting post-transcriptional regulation overcame stemness-related malignancy and may be a novel strategy for breast cancer treatments.

Mitochondrial aldehyde dehydrogenase (ALDH2) rescues cardiac contractile dysfunction in an APP/PS1 murine model of Alzheimer's disease via inhibition of ACSL4-dependent ferroptosis.

Alzheimer's disease (AD) is associated with high incidence of cardiovascular events but the mechanism remains elusive. Our previous study reveals a tight correlation between cardiac dysfunction and low mitochondrial aldehyde dehydrogenase (ALDH2) activity in elderly AD patients. In the present study we investigated the effect of ALDH2 overexpression on cardiac function in APP/PS1 mouse model of AD. Global ALDH2 transgenic mice were crossed with APP/PS1 mutant mice to generate the ALDH2-APP/PS1 mutant mice. Cognitive function, cardiac contractile, and morphological properties were assessed. We showed that APP/PS1 mice displayed significant cognitive deficit in Morris water maze test, myocardial ultrastructural, geometric (cardiac atrophy, interstitial fibrosis) and functional (reduced fractional shortening and cardiomyocyte contraction) anomalies along with oxidative stress, apoptosis, and inflammation in myocardium. ALDH2 transgene significantly attenuated or mitigated these anomalies. We also noted the markedly elevated levels of lipid peroxidation, the essential lipid peroxidation enzyme acyl-CoA synthetase long-chain family member 4 (ACSL4), the transcriptional regulator for ACLS4 special protein 1 (SP1) and ferroptosis, evidenced by elevated NCOA4, decreased GPx4, and SLC7A11 in myocardium of APP/PS1 mutant mice; these effects were nullified by ALDH2 transgene. In cardiomyocytes isolated from WT mice and in H9C2 myoblasts in vitro, application of Aβ (20 μM) decreased cell survival, compromised cardiomyocyte contractile function, and induced lipid peroxidation; ALDH2 transgene or activator Alda-1 rescued Aβ-induced deteriorating effects. ALDH2-induced protection against Aβ-induced lipid peroxidation was mimicked by the SP1 inhibitor tolfenamic acid (TA) or the ACSL4 inhibitor triacsin C (TC), and mitigated by the lipid peroxidation inducer 5-hydroxyeicosatetraenoic acid (5-HETE) or the ferroptosis inducer erastin. These results demonstrate an essential role for ALDH2 in AD-induced cardiac anomalies through regulation of lipid peroxidation and ferroptosis.

Analysis of human aldehyde dehydrogenases (ALDH) gene expression pattern in breast cancer tissue samples: rutin-copper complex inhibit the breast cancer cell proliferation

BackgroundHigher aldehyde dehydrogenases (ALDH) activity is one of the important signatures of breast cancer appearance and has been associated with poor prognosis. ALDH1A3 has been over-expressed in breast cancer patients. This study aims to analyze gene expression patterns of 18 ALDH isozymes in breast cancer tissue samples. It is carried out using a chip-based microarray, next-generation DNA sequencing of ALDH2 gene following in silico study to identify the natural products which act as inhibitors for over-expressed ALDH isoforms. The synthesis of rutin-copper complex and cell viability assay is carried out on MDA-MB-468 cell line.ResultsALDH1A3 and ALDH18A1 have shown the highest positive mean fold of variation; whereas, ALDH2 and ALDH1A2 have shown the highest negative mean fold variation. In silico studies revealed that rutin has the highest binding affinity with both ALDH1A3 and ALDH18A1 and supported with IC50 value of rutin against MDA-MB-468 cells (144.50 μg/ml). Chemically synthesized rutin-copper complex significantly lowered the IC50 value to 119.40 μg/ml. The next-generation sequencing study provides the novel single nucleotide polymorphism (SNP) from T to G in the ALDH2 gene.ConclusionThe present study signifies that, along with ALDH1A3, ALDH18A1 also acts as a marker for breast cancer. Apart from that, inhibitors of ALDH1A3 and ALDH18A1 were attained. Perhaps the single nucleotide polymorphism (SNP) obtained during the mutation analysis may be the probable cause of the highest downregulation of ALDH2 in breast cancer.

A Novel ALDH2 Activator AD-9308 Improves Diastolic and Systolic Myocardial Functions in Streptozotocin-Induced Diabetic Mice

Diabetes mellitus has reached epidemic proportion worldwide. One of the diabetic complications is cardiomyopathy, characterized by early left ventricular (LV) diastolic dysfunction, followed by development of systolic dysfunction and ventricular dilation at a late stage. The pathogenesis is multifactorial, and there is no effective treatment yet. In recent years, 4-hydroxy-2-nonenal (4-HNE), a toxic aldehyde generated from lipid peroxidation, is implicated in the pathogenesis of cardiovascular diseases. Its high bioreactivity toward proteins results in cellular damage. Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is the major enzyme that detoxifies 4-HNE. The development of small-molecule ALDH2 activator provides an opportunity for treating diabetic cardiomyopathy. This study found that AD-9308, a water-soluble andhighly selective ALDH2 activator, can improve LV diastolic and systolic functions, and wall remodeling in streptozotocin-induced diabetic mice. AD-9308 treatment dose-dependently lowered serum 4-HNE levels and 4-HNE protein adducts in cardiac tissue from diabetic mice, accompanied with ameliorated myocardial fibrosis, inflammation, and apoptosis. Improvements of mitochondrial functions, sarco/endoplasmic reticulumcalcium handling and autophagy regulation were also observed in diabetic mice with AD-9308 treatment. In conclusion, ADLH2 activation effectively ameliorated diabetic cardiomyopathy, which may be mediated through detoxification of 4-HNE. Our findings highlighted the therapeutic potential of ALDH2 activation for treating diabetic cardiomyopathy.

Interactions of COMT and ALDH2 Genetic Polymorphisms on Symptoms of Parkinson's Disease.

(1) Background: Monoamine neurotransmitters play essential roles in the normal functioning of our nervous system. However, the metabolism of monoamine neurotransmitters is accompanied by the production of neurotoxic metabolites, and inefficient removal of the metabolites has been suggested to cause neurodegeneration. (2) Methods: To examine the effect of reduced activity of catechol-O-methyltransferase (COMT) and aldehyde dehydrogenase 2 (ALDH2) conferred by single nucleotide polymorphisms COMT rs4680(A) and ALDH2 rs671(A) on the symptoms of patients with Parkinson’s disease (PD), a total of 114 PD patients were recruited cross-sectionally and received genotyping for rs4680 and rs671 along with MDS-UPDRS evaluation. (3) Results: We found that patients carrying rs4680(A) had more severe bradykinesia in the upper extremity and rest tremor. Besides, patients carrying rs671(A) had more difficulty maintaining personal hygiene, while patients with genotype rs671(GG) had higher scores in the item “depressed mood.” More importantly, we found the effect of rs4680 to be moderated by rs671 SNP for the symptom of “hand movements.” The detrimental impact of rs4680(A) is more pronounced in the presence of genotype rs671(GG). (4) Conclusions: This study facilitates a deeper understanding of the detrimental effect of reduced activity of COMT and ALDH2 conferred by genetic variation and provides novel insight into the interactions between enzymes metabolizing monoamine neurotransmitters in the pathogenesis of PD.

Major aldehyde dehydrogenase AldFGH of Gluconacetobacter diazotrophicus is independent of pyrroloquinoline quinone but dependent on molybdopterin for acetic acid fermentation.

Acetic acid fermentation involves the oxidation of ethanol to acetic acid via acetaldehyde as the intermediate and is catalyzed by the membrane-bound alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) of acetic acid bacteria. Although ADH depends on pyrroloquinoline quinone (PQQ), the prosthetic group associated with ALDH remains a matter of debate. This study aimed to address the dependency of ALDH of Gluconacetobacter diazotrophicus strain PAL5 on PQQ and the physiological role of ALDH in acetic acid fermentation. We constructed deletion mutant strains for both the ALDH gene clusters of PAL5, aldFGH and aldSLC. In addition, the adhAB operon for ADH was eliminated, since it shows ALDH activity. The triple-deletion derivative ΔaldFGH ΔaldSLC ΔadhAB failed to show ALDH activity, which suggested that ALDH activity in PAL5 is derived from these three enzyme complexes. Since the single-gene cluster deletion derivative ΔaldFGH lost most ALDH activity, and accumulated much higher acetaldehyde than wild type under acetic acid fermentation conditions, we concluded that AldFGH functions as the major ALDH in PAL5. Furthermore, deletion of the PQQ biosynthesis gene cluster (pqqABCDE) abolished ADH activity completely, but did not affect ALDH activity. Instead, the molybdopterin biosynthesis gene deletion derivatives lost ALDH activity. Thus, we concluded that the AldFGH and AldSLC complexes of Ga. diazotrophicus PAL5 require a form of molybdopterin but not PQQ for ALDH activity. KEY POINTS: • AldFGH is the major aldehyde dehydrogenase in Gluconacetobacter diazotrophicus PAL5. • Acetaldehyde accumulated from ethanol in the absence of AldFGH. • Molybdopterin, rather than pyrroloquinoline quinone, is required for AldFGH.

The possible protective effect of aldehyde dehydrogenase 2 agonist (Alda-1) on doxorubicin induced toxicity of the left ventricular cardiomyocytes of adult male mice.

ABSTRACTBackground: Doxorubicin (DOX) is an effective antineoplastic drug. However, its cardiotoxicity is a major obstacle that limit its use. Therefore, a novel protective agent is urgently needed. Enzyme activation recently gained much interest as a new therapeutic strategy. In this context, Alda-1 is a newly emerged molecule in the field of cardioprotection through its activation of aldehyde dehydrogenase 2 enzyme.Aim of the study: To evaluate the possible protective effect of aldehyde dehydrogenase agonist Alda-1 on doxorubicin induced cardiotoxicity. Material and methods: Twenty-four adult male C57BL/6 mice were divided equally into 4 groups. Group I received intraperitoneal injection of saline. Group II received intraperitoneal injection of Alda-1 (10 mg/kg) daily for 5 days. Group III received a single intraperitoneal injection of DOX (20 mg/kg). Group IV received both DOX and Alda-1 in the same regimen as in groups II and III, Alda-1 was administered 1 day before DOX. All mice were euthanized on the 5th day following DOX administration. Blood samples were collected, hearts were excised and further processed for anatomical, histological and biochemical analysis.Results: DOX administration caused extensive cardiotoxicity as evident by the marked decrease in the heart weight and the extensive myocardial lesions shown by the light and electron microscopic examination. Moreover, biochemical serum markers of cardiac injury (CK-MB &LDH) was markedly elevated. Increased oxidative stress was also encountered as shown by the decreased serum TAC and increased tissue MDA. Furthermore, mitochondrial morphometry showed increased mitochondrial size. However, concomitant administration of Alda-1 with DOX have markedly alleviated the heart injury as shown by the restoration of the heart weight and cardiac architecture together with preservation of the mitochondrial structure. Moreover, Alda-1 has ameliorated the biochemical markers of cardiac injury and the oxidative stress.Conclusion: Alda-1 provides a valuable protective effect against doxorubicin triggered cardiotoxicity.

Effect of water-soluble propolis administration on the ethanol-induced hangover in rats.

Water soluble propolis was prepared using β-cyclodextrin, and its effect on an ethanol-induced hangover was examined in Sprague-Dawley (SD) rats fed with ethanol. When SD rats were administrated with propolis 30min after ethanol feeding, ethanol content in the rat serum decreased 2.1 times 1h after ethanol feeding. Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) activity in rat liver increased 3.0 and 4.4 times, respectively, 1h after ethanol feeding and administration of propolis 30min after ethanol feeding. There were no differences in the expression of ADH and ALDH genes regardless of propolis administration. These results indicated that a decrease in ethanol content in the serum was not due to an increase in the expression of ADH or ALDH genes but rather, an increase in activities of ADH and ALDH.

Dietary iso-α-acids prevent acetaldehyde-induced liver injury through Nrf2-mediated gene expression.

Acetaldehyde is the major toxic metabolite of alcohol (ethanol) and enhances fibrosis of the liver through hepatic stellate cells. Additionally, alcohol administration causes the accumulation of reactive oxygen species (ROS), which induce hepatocyte injury-mediated lipid peroxidation. Iso-α-acids, called isohumulones, are bitter acids in beer. The purpose of this study was to investigate the protective effects of iso-α-acids against alcoholic liver injury in hepatocytes in mice. C57BL/6N mice were fed diets containing isomerized hop extract, which mainly consists of iso-α-acids. After 7 days of feeding, acetaldehyde was administered by a single intraperitoneal injection. The acetaldehyde-induced increases in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were suppressed by iso-α-acids intake. Hepatic gene expression analyses showed the upregulation of detoxifying enzyme genes, glutathione-S-transferase (GST) and aldehyde dehydrogenase (ALDH). In vitro, iso-α-acids upregulated the enzymatic activities of GST and ALDH and induced the nuclear translocation of nuclear factor-erythroid-2-related factor 2 (Nfe2l2; Nrf2), a master regulator of antioxidant and detoxifying systems. These results suggest that iso-α-acid intake prevents acetaldehyde-induced liver injury by reducing oxidative stress via Nrf2-mediated gene expression.

GSNOR and ALDH2 alleviate traumatic spinal cord injury

Traumatic spinal cord injury (SCI) enhances the activity of S-nitrosoglutathione reductase (GSNOR) and inhibits the mitochondrial aldehyde dehydrogenase 2 (ALDH2) activity, resulting in prolonged and sustained pain and functional deficits. This study's objective was to test the hypotheses that GSNOR’s specific inhibitor N6022 mitigates pain and improves functional recovery in a mouse model of SCI. Furthermore, the degree of recovery is enhanced and the rate of recovery is accelerated by an ALDH2 activator Alda-1. Using both wild-type and GSNOR−/− mice, the SCI model deployed for groups was contusion at the T9-T10 vertebral level. The enzymatic activity of GSNOR and ALDH2 was measured, and the expression of GSNOR and ALDH2 was determined by western blot analysis. Functional improvements in experimental animals were assessed with locomotor, sensorimotor, and pain-like behavior tests. Wild-type SCI animals had enhanced GSNOR activity and decreased ALDH2 activity, leading to neurovascular dysfunction, edema, and worsened functional outcomes, including locomotor deficits and pain. Compared to wild-type SCI mice, GSNOR−/− mice had better functional outcomes. Monotherapy with either GSNOR inhibition by N6022 or enhanced ALDH2 activity by Alda-1 correlated well with functional recovery and lessened pain. However, combination therapy provided synergistic pain-relieving effects and more significant functional recovery compared with monotherapy. Conclusively, dysregulations in GSNOR and ALDH2 are among the causative mechanisms of SCI injury. Either inhibiting GSNOR or activating ALDH2 ameliorates SCI. Combining the specific inhibitor of GSNOR (N6022) with the selective activator of ALDH2 (Alda-1) provides greater protection to the neurovascular unit and confers greater functional recovery. The study is novel, and the combination therapy (N6022 + Alda-1) possesses translational potential.

The Predict Significance of ALDH Activity to the Relapse of t(8;21) Acute Myeloid Leukemia Patients at Complete Remission

To investigate the predict significance of the high aldehyde dehydrogenase activity (ALDH+) propitiation to the relapse of t(8;21) acute myeloid leukemia(AML) patients before and after treatment. Bone marrow samples of 23 t(8;21) AML patients diagnosis and achieved complete remission in our hospital from April 2015 to June 2016 were collected, then flow cytometry method was used to detect the activity of ALDH, relationship between it and relapse was analyzed. All the patients were followed up for a median of 32 (2-52) months. The median percentage of CD34+CD38- and CD34+CD38-ALDH+ cells among nucleated cells were 2.7 (0.36-35.7)% and 0.017 (0.0013-0.62)% at diagnosis, respectively. Among the bone marrow samples in patients achieved CR, the median percentage of CD34+CD38- cells was 0.035 (0.0064-0.66)%, and it was significantly decreased as compared with the percentage at diagnosis (P<0.001); The median percentage of CD34+CD38-ALDH+ cells was 0.014 (0.0019-0.24)%, and it showed no different as compared with the percentage at diagnosis (P=0.45). Survival analysis showed that patients with higher percentage of CD34+CD38- and CD34+CD38-ALDH+ cells at diagnosis tended to the lower 3-year relapse-free survival (RFS) (P=0.27 and 0.21). Furthermore, patients with higher percentage of CD34+CD38- and CD34+CD38-ALDH+ cells when achieved CR had a significant lower 3-year RFS rates (P=0.010 and 0.0044) as compared with those with lower percentage of CD34+CD38- and CD34+CD38-ALDH+ cells. Multivariate analysis showed that higher percentage of CD34+CD38-ALDH+ cells when achieved CR was an independent factor affecting RFS of the patients. The percentage of CD34+CD38-ALDH+ cells at CR in t(8;21) AML patients could predicts relapse, and had more profound predictive significance for relapse than the percentage of CD34+CD38- cells.

Identification of triptonide as a therapeutic agent for triple negative breast cancer treatment

Triple-negative breast cancer (TNBC) is associated with a high rate of early recurrence and distant metastasis, frequent development of therapeutic resistance, and a poor prognosis. There is a lack of targeted therapies for this aggressive subtype of breast cancer. Identifying novel effective treatment modalities for TNBC remains an urgent and unmet clinical need. In this study, we investigated the anti-cancer effect of triptonide, a natural compound derived from the traditional Chinese medicinal herb Tripterygium wilfordii Hook F, in TNBC. We found that triptonide inhibits human TNBC cell growth in vitro and growth of TNBC xenograft mammary tumors. It induces apoptosis and suppresses stem-like properties as indicated by reduced mammosphere formation and aldehyde dehydrogenase activity in TNBC cells. We show that triptonide downregulates multiple cancer stem cell-associated genes but upregulates SNAI1 gene expression. In support of SNAI1 induction as a negative feedback response to triptonide treatment, in vitro-derived triptonide-resistant HCC1806 cells display a markedly higher expression of SNAI1 compared with parental cells. Mechanistically, the increase of SNAI1 expression is mediated by the activation of JNK signaling, but not by ERK and AKT, two well-established SNAI1 regulators. Furthermore, knockdown of SNAI1 in the triptonide-resistant HCC1806 cells increases sensitivity to triptonide and reduces mammosphere formation. These results indicate that triptonide holds promise as a novel anti-tumor agent for TNBC treatment. Our study also reveals a SNAI1-associated feedback mechanism which may lead to acquired resistance to triptonide.

Integrated bioinformatics analysis for the identification of key genes and signaling pathways in thyroid carcinoma.

Thyroid carcinoma (TC) is one of the most common types of endocrine neoplasm with poor prognosis due to its aggressive behavior. Biomarkers for early diagnosis and prevention of TC are in urgent demand. By using a bioinformatics analysis, the present study aimed to identify essential genes and pathways associated with TC. First, the GSE27155 and GSE50901 expression profiles were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were obtained using the two microarray datasets and further subjected to integrated analysis. A gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed 45 common DEGs in the two datasets. GO and KEGG pathway analysis indicated that the biological functions of the DEGs included protein binding, cardiac muscle cell potential involved in contraction, aldehyde dehydrogenase activity, the TGF-β receptor signaling pathway and the canonical Wnt signaling pathway. A protein-protein interaction network was also constructed and visualized to display the nodes of the top 9 up- and 36 downregulated common DEGs. The integrated bioinformatics analysis indicated that potassium inwardly rectifying channel subfamily J member 2 (KCNJ2) was the most significantly upregulated DEG. The transcriptional levels of KCNJ2 were confirmed to be elevated in TC tissues compared with those in normal tissues using reverse transcription-quantitative PCR analysis. Furthermore, the expression level of KCNJ2 was significantly associated with the 5-year survival rate of patients with TC, which was determined using the Kaplan-Meier method. In TC cell lines, KCNJ2 was also upregulated as compared with that in a normal control cell line. Finally, small interfering RNA was used to knock down the expression of KCNJ2, which was demonstrated to inhibit cell proliferation, migration and invasion, while increasing apoptosis in TC cells. In conclusion, in the present study, KCNJ2 was screened as an oncogene with a crucial role in TC development and progression and may represent a promising candidate biomarker and therapeutic target for TC.

Protective Effects of Antrodia cinnamomea and Its Constituent Compound Dehydroeburicoic Acid 32 Against Alcoholic Fatty Liver Disease.

Alcoholic fatty liver disease (AFLD), a leading chronic hepatic disease, affects an increasing number of people, and no effective drugs for the treatment of AFLD are available. Antrodia cinnamomea (AC) can inhibit AFLD, but its mechanisms and the effective compound in AC are unknown. We aimed to explore the anti-AFLD mechanism of AC and the active compound within AC. Wild-type (WT) C57BL/6J mice underwent 4 weeks of daily ethanol (EtOH) feeding to induce AFLD. AC or dehydroeburicoic acid 32 (DEA32), a compound in AC, was given to the mice. Parallel experiments to assess the effect of AC were conducted in aldehyde dehydrogenase 2 (ALDH2)-knockout (KO) mice. Primary mouse hepatocytes were incubated with ethanol and Alda- 1 (an ALDH2 agonist), AC or DEA32. In WT mice with AFLD, AC reduced lipid deposition, increased the expression and activity of ALDH2, reduced the acetaldehyde content, and downregulated the expression of lipogenic and inflammatory genes in the liver. These effects of AC disappeared in ALDH2 KO mice. DEA32 was identified as an active compound in AC, as its effects on EtOH-treated WT hepatocytes were similar to those of AC, which were comparable to the effects of Alda-1. These effects of DEA32 disappeared in EtOH-treated ALDH2 KO hepatocytes. Furthermore, in WT mice with AFLD, DEA32 reduced lipid deposition, increased the activity of ALDH2, and reduced the accumulation of acetaldehyde in the liver. DEA32 also downregulated the mRNA expression of genes related to lipogenesis and inflammation. AC and its constituent compound DEA32 inhibit AFLD by upregulating ALDH2 activity, accelerating acetaldehyde metabolism, and suppressing lipogenesis and inflammation in the liver.