Aldehyde Reductase Activity of Carboxylic Acid Reductases

Carboxylic acid reductase enzymes (CARs) are well known for the reduction of a wide range of carboxylic acids to the respective aldehydes. One of the essential CAR domains - the reductase domain (R-domain) - was recently shown to catalyze the standalone reduction of carbonyls, including aldehydes, which are typically considered to be the final product of carboxylic acid reduction by CAR. We discovered that the respective full-length CARs were equally able to reduce aldehydes. Herein we aimed to shed light on the impact of this activity on aldehyde production and acid reduction in general. Our data explains previously inexplicable results and a new CAR from Mycolicibacterium wolinskyi is presented.

Novel spiroindoline derivatives targeting aldose reductase against diabetic complications: Bioactivity, cytotoxicity, and molecular modeling studies

Despite significant developments in therapeutic strategies, Diabetes Mellitus remains an increasing concern, leading to various complications, e.g., cataracts, neuropathy, retinopathy, nephropathy, and several cardiovascular diseases. The polyol pathway, which involves Aldose reductase (AR) as a critical enzyme, has been focused on by many researchers as a target for intervention. On the other hand, spiroindoline-based compounds possess remarkable biological properties. This guided us to synthesize novel spiroindoline oxadiazolyl-based acetate derivatives and investigate their biological activities. The synthesized molecules' structures were confirmed herein, using IR, NMR (1H and 13C), and Mass spectroscopy. All compounds were potent inhibitors with KI constants spanning from 0.186 ± 0.020 μM to 0.662 ± 0.042 μM versus AR and appeared as better inhibitors than the clinically used drug, Epalrestat (EPR, KI: 0.841 ± 0.051 μM). Besides its remarkable inhibitory profile compared to EPR, compound 6k (KI: 0.186 ± 0.020 μM) was also determined to have an unusual pharmacokinetic profile. The results showed that 6k had less cytotoxic effect on normal mouse fibroblast (L929) cells (IC50 of 569.58 ± 0.80 μM) and reduced the viability of human breast adenocarcinoma (MCF-7) cells (IC50 of 110.87 ± 0.42 μM) more than the reference drug Doxorubicin (IC50s of 98.26 ± 0.45 μM and 158.49 ± 2.73 μM, respectively), thus exhibiting more potent anticancer activity. Moreover, molecular dynamic simulations for 200 ns were conducted to predict the docked complex's stability and reveal significant amino acid residues that 6k interacts with throughout the simulation.

Endogenous reductase activities for the generation of ribitol-phosphate, a CDP-ribitol precursor, in mammals

The core M3 O-mannosyl glycan on α-dystroglycan serves as the binding epitope for extracellular matrix molecules. Defects in core M3 glycans cause congenital muscular dystrophies that are collectively known as dystroglycanopathies. The core M3 glycan contains a tandem D-ribitol-5-phosphate (Rbo5P) structure, which is synthesized by the Rbo5P-transferases fukutin and fukutin-related protein using CDP-ribitol (CDP-Rbo) as a donor substrate. CDP-Rbo is synthesized from CTP and Rbo5P by CDP-Rbo pyrophosphorylase A. However, the Rbo5P biosynthesis pathway has yet to be elucidated in mammals. Here, we investigated the reductase activities toward four substrates, including ribose, ribulose, ribose-phosphate and ribulose-phosphate, to identify the intracellular Rbo5P production pathway and elucidated the role of the aldo-keto reductases AKR1A1, AKR1B1 and AKR1C1 in those pathways. It was shown that the ribose reduction pathway is the endogenous pathway that contributes most to Rbo5P production in HEK293T cells and that AKR1B1 is the major reductase in this pathway.

Mining and tailor-made engineering of a novel keto reductase for asymmetric synthesis of structurally hindered γ- and δ-lactones

A novel carbonyl reductase from Hyphopichia burtoni (HbKR) was discovered by gene mining. HbKR is a NADPH-dependent dual function enzyme with reduction and oxidation activity belonging to SDR superfamily. HbKR strictly follows Prelog priority in the reduction of long-chain aliphatic keto acids/esters containing remote carbonyl groups, such as 4-oxodecanoic acid and 5-oxodecanoic acid, producing (S)-γ-decalactone and (S)-δ-decalactone in >99 % e.e. Tailor-made engineering of HbKR was conducted to improve its catalytic efficiency. Variant F207A/F86M was obtained with specific activity of 8.37 U/mg toward 5-oxodecanoic acid, which was 9.7-fold of its parent. Employing F207A/F86M, 100 mM 5-oxodecanoic acid could be reduced into optically pure (S)-δ-decalactone. Molecular docking analysis indicates that substitution of aromatic Phe with smaller residues renders sufficient space for accommodating substrates in a more stable conformation. This study offers an efficient biocatalyst for the biosynthesis of (S)-lactones, and provides guidance for engineering carbonyl reductases toward structurally hindered substrates.

In vitro evaluation of the reductive carbonyl idarubicin metabolism to evaluate inhibitors of the formation of cardiotoxic idarubicinol via carbonyl and aldo-keto reductases

The most important dose-limiting factor of the anthracycline idarubicin is the high risk of cardiotoxicity, in which the secondary alcohol metabolite idarubicinol plays an important role. It is not yet clear which enzymes are most important for the formation of idarubicinol and which inhibitors might be suitable to suppress this metabolic step and thus would be promising concomitant drugs to reduce idarubicin-associated cardiotoxicity. We, therefore, established and validated a mass spectrometry method for intracellular quantification of idarubicin and idarubicinol and investigated idarubicinol formation in different cell lines and its inhibition by known inhibitors of the aldo-keto reductases AKR1A1, AKR1B1, and AKR1C3 and the carbonyl reductases CBR1/3. The enzyme expression pattern differed among the cell lines with dominant expression of CBR1/3 in HEK293 and MCF-7 and very high expression of AKR1C3 in HepG2 cells. In HEK293 and MCF-7 cells, menadione was the most potent inhibitor (IC50 = 1.6 and 9.8 µM), while in HepG2 cells, ranirestat was most potent (IC50 = 0.4 µM), suggesting that ranirestat is not a selective AKR1B1 inhibitor, but also an AKR1C3 inhibitor. Over-expression of AKR1C3 verified the importance of AKR1C3 for idarubicinol formation and showed that ranirestat is also a potent inhibitor of this enzyme. Taken together, our study underlines the importance of AKR1C3 and CBR1 for the reduction of idarubicin and identifies potent inhibitors of metabolic formation of the cardiotoxic idarubicinol, which should now be tested in vivo to evaluate whether such combinations can increase the cardiac safety of idarubicin therapies while preserving its efficacy.

Assessment of the Anti-Breast Cancer Effects of Urolithin with Molecular Docking Studies in the In Vitro Condition: Introducing a Novel Chemotherapeutic Drug

A lot of research has been done on using natural items as diabetes treatment. The molecular docking study was conducted to evaluate the inhibitory activities of urolithin A against α-amylase, α-glucosidase, and aldose reductase. The molecular docking calculations indicated the probable interactions and the characteristics of these contacts at an atomic level. The results of the docking calculations showed the docking score of urolithin A against α-amylase was -5.169 kcal/mol. This value for α-glucosidase and aldose reductase was -3.657 kcal/mol and -7.635 kcal/mol, respectively. In general, the outcomes of the docking calculations revealed that urolithin A can construct several hydrogen bonds and hydrophobic contacts with the assessed enzymes and reduces their activities considerably. The properties of urolithin against common human breast cancer cell lines, i.e., SkBr3, MDA-MB-231, MCF-7, Hs578T, Evsa-T, BT-549, AU565 and 600MPE were evaluated. The IC50 of the urolithin was 400, 443, 392, 418, 397, 530, 566 and 551 against SkBr3, MDA-MB-231, MCF-7, Hs578T, Evsa-T, BT-549, AU565 and 600MPE, respectively. After doing the clinical trial studies, the recent molecule may be used as an anti-breast cancer supplement in humans. IC50 values of urolithin A on α-amylase, α-glucosidase, and aldose reductase enzymes were obtained at 16.14, 1.06 and 98.73 µM, respectively.

Proteomics-based screening of AKR1B1 as a therapeutic target and validation study for sepsis-associated acute kidney injury

Background

Sepsis and sepsis-associated acute kidney injury (SA-AKI) pose significant global health challenges, necessitating the development of innovative therapeutic strategies. Dysregulated protein expression has been implicated in the initiation and progression of sepsis and SA-AKI. Identifying potential protein targets and modulating their expression is crucial for exploring alternative therapies.

Method

We established an SA-AKI rat model using cecum ligation perforation (CLP) and employed differential proteomic techniques to identify protein expression variations in kidney tissues. Aldose reductase (AKR1B1) emerged as a promising target. The SA-AKI rat model received treatment with the aldose reductase inhibitor (ARI), epalrestat. Blood urea nitrogen (BUN) and creatinine (CRE) levels, as well as IL-1β, IL-6 and TNF-α levels in the serum and kidney tissues, were monitored. Hematoxylin-eosin (H-E) staining and a pathological damage scoring scale assessed renal tissue damage, while protein blotting determined PKC (protein kinase C)/NF-κB pathway protein expression.

Result

Differential proteomics revealed significant downregulation of seven proteins and upregulation of 17 proteins in the SA-AKI rat model renal tissues. AKR1B1 protein expression was notably elevated, confirmed by Western blot. ARI prophylactic administration and ARI treatment groups exhibited reduced renal injury, low BUN and CRE levels and decreased IL-1β, IL-6 and TNF-α levels compared to the CLP group. These changes were statistically significant (P < 0.05). AKR1B1, PKC-α, and NF-κB protein expression levels were also lowered in the ARI prophylactic administration and ARI treatment groups compared to the CLP group (P < 0.05).

Conclusions

Epalrestat appeared to inhibit the PKC/NF-κB inflammatory pathway by inhibiting AKR1B1, resulting in reduced inflammatory cytokine levels in renal tissues and blood. This mitigated renal tissue injuries and improved the systemic inflammatory response in the severe sepsis rat model. Consequently, AKR1B1 holds promise as a target for treating sepsis-associated acute kidney injuries.

Gastric Cancer Immune Subtypes and Prognostic Modeling: Insights from Aging-Related Gene Analysis

Gastric cancer (GC) is highly heterogeneous and influenced by aging-related factors. This study aimed to improve individualized prognostic assessment of GC by identifying aging-related genes and subtypes. Immune scores of GC samples from GEO and TCGA databases were calculated using ESTIMATE and scored as high immune (IS_high) and low immune (IS_low). ssGSEA was used to analyze immune cell infiltration. Univariate Cox regression was employed to identify prognosis-related genes. LASSO regression analysis was used to construct a prognostic model. GSVA enrichment analysis was applied to determine pathways. CCK-8, wound healing, and Transwell assays tested the proliferation, migration, and invasion of the GC cell line (AGS). Cell cycle and aging were examined using flow cytometry, β-galactosidase staining, and Western blotting. Two aging-related GC subtypes were identified. Subtype 2 was characterized as lower survival probability and higher risk, along with a more immune-responsive tumor microenvironment. Three genes (IGFBP5, BCL11B, and AKR1B1) screened from aging-related genes were used to establish a prognosis model. The AUC values of the model were greater than 0.669, exhibiting strong prognostic value. In vitro, IGFBP5 overexpression in AGS cells was found to decrease viability, migration, and invasion, alter the cell cycle, and increase aging biomarkers (SA-β-galactosidase, p53, and p21). This analysis uncovered the immune characteristics of two subtypes and aging-related prognosis genes in GC. The prognostic model established for three aging-related genes (IGFBP5, BCL11B, and AKR1B1) demonstrated good prognosis performance, providing a foundation for personalized treatment strategies aimed at GC.

Inhibitory effect of Nifedipine on aldose reductase delays cataract progression

Aldose reductase (ALR2) is a rate-limiting component of the polyol pathway, which is essential for the NADPH-mediated conversion from glucose to sorbitol. ALR2 dysregulation has been linked to α-crystallin aggregation, increased oxidative stress, and calcium inflow, all of which contribute to a diabetic cataract. Given its crucial role in occular pathologies, ALR2 has emerged as a promising target to treat oxidative stress and hyperglycaemic condition which form the underlying cause of diabetic cataracts. However, several of them had issues with sensitivity and specificity to ALR2, despite being screened as effective ALR2 inhibitors from a wide range of structurally varied molecules. The current study investigates the inhibitory potential of Nifedipine, an analog of the dihydro nicotinamide class of compounds against ALR2 activity. The enzyme inhibition studies were supported by in vitro biomolecular interactions, molecular modeling approaches, and in vivo validation in diabetic rat models. Nifedipine demonstrated appreciable inhibitory potential with the purified recombinant hAR (human aldose reductase; with an IC50 value of 2.5 µM), which was further supported by Nifedipine-hAR binding affinity (Kd = 2.91 ± 1.87 × 10-4 M) by ITC and fluorescence quenching assays. In the in vivo models of STZ-induced diabetic rats, Nifedipine delayed the onset progression of cataracts by preserving the antioxidant enzyme activity (SOD, CAT, and GPX GSH, TBARS, and protein carbonyls) and was shown to retain the α-crystallin chaperone activity by reducing the calcium levels in the diabetic rat lens. In conclusion, our results demonstrate effective inhibition of ALR2 by Nifedipine, resulting in amelioration of diabetic cataract conditions by lowering oxidative and osmotic stress while retaining the chaperone activity of α-crystallins. The present study could be envisaged to improve the eye condition in older adults upon Nifedipine treatment.

Del Nido cardioplegia or potassium induces Nrf2 and protects cardiomyocytes against oxidative stress

Open heart surgery is often an unavoidable procedure for the treatment of coronary artery disease. The procedure-associated reperfusion injury affects postoperative cardiac performance and long-term outcomes. We addressed here whether cardioplegia essential for cardiopulmonary bypass surgery activates Nrf2, a transcription factor regulating the expression of antioxidant and detoxification genes. With commonly used cardioplegic solutions, high K+, low K+, Del Nido (DN), histidine-tryptophan-ketoglutarate (HTK), and Celsior (CS), we found that DN caused a significant increase of Nrf2 protein in AC16 human cardiomyocytes. Tracing the ingredients in DN led to the discovery of KCl at the concentration of 20-60 mM capable of significant Nrf2 protein induction. The antioxidant response element (ARE) luciferase reporter assays confirmed Nrf2 activation by DN or KCl. Transcriptomic profiling using RNA-seq revealed that oxidation-reduction as a main gene ontology group affected by KCl. KCl indeed elevated the expression of classical Nrf2 downstream targets, including TXNRD1, AKR1C, AKR1B1, SRXN1, and G6PD. DN or KCl-induced Nrf2 elevation is Ca2+ concentration dependent. We found that KCl decreased Nrf2 protein ubiquitination and extended the half-life of Nrf2 from 17.8 to 25.1 mins. Knocking out Keap1 blocked Nrf2 induction by K+. Nrf2 induction by DN or KCl correlates with the protection against reactive oxygen species generation or loss of viability by H2O2 treatment. Our data support that high K+ concentration in DN cardioplegic solution can induce Nrf2 protein and protect cardiomyocytes against oxidative damage.NEW & NOTEWORTHY Open heart surgery is often an unavoidable procedure for the treatment of coronary artery disease. The procedure-associated reperfusion injury affects postoperative cardiac performance and long-term outcomes. We report here that Del Nido cardioplegic solution or potassium is an effective inducer of Nrf2 transcription factor, which controls the antioxidant and detoxification response. This indicates that Del Nido solution is not only essential for open heart surgery but also exhibits cardiac protective activity.

Torachrysone-8-O-β-d-glucoside mediates anti-inflammatory effects by blocking aldose reductase-catalyzed metabolism of lipid peroxidation products

Aldose reductase (AR) is an important enzyme involved in the reduction of various aldehyde and carbonyl compounds, including the highly reactive and toxic 4-hydroxynonenal (4-HNE), which has been linked to the progression of various pathologies such as atherosclerosis, hyperglycemia, inflammation, and tumors. AR inhibitors have potential therapeutic benefits for these diseases by reducing lipid peroxidation and mitigating the harmful effects of reactive aldehydes. In this study, we found that torachrysone-8-O-β-d-glucoside (TG), a natural product isolated from Polygonum multiflorum Thunb., functions as an effective inhibitor of AR, exhibiting potent effects in clearing reactive aldehydes and reducing inflammation. TG up-regulated the mRNA levels of several antioxidant factors downstream of NRF2, especially glutathione S-transferase (GST), which is significantly increased, thus detoxifying 4-HNE by facilitating the conjugation of 4-HNE to glutathione, forming glutathione-4-hydroxynonenal (GS-HNE). By employing a combination of molecular docking, cellular thermal shift assay, and enzyme activity experiments, we demonstrated that TG exhibited strong binding affinity with AR and inhibited its activity and blocked the conversion of GS-HNE to glutathionyl-1,4-dihydroxynonene (GS-DHN), thereby preventing the formation of protein adducts and inducing severe cellular damage. This study provides novel insights into the anti-inflammatory mechanisms of AR inhibitors and offers potential avenues for developing therapeutic strategies for AR-related pathologies. Our findings suggest that TG, as an AR inhibitor, may hold promise as a therapeutic agent for treating conditions characterized by excessive lipid peroxidation and inflammation. Further investigations are needed to fully explore the clinical potential of TG and evaluate its efficacy in the treatment and management of these complex diseases.

Inhibitory effect of gallic acid from Thunbergia mysorensis against α-glucosidase, α-amylase, aldose reductase and their interaction: Inhibition kinetics and molecular simulations

In this exploration, we assessed the antihyperglycaemic properties of methanol extract of flowers of Thunbergia mysorensis (MeT) against α-glucosidase, α-amylase and aldose reductase enzymes for the effective management of postprandial hyperglycemia. Hyperglycemia occurs when the body lacks enough insulin or is unable to correctly utilize it. MeT inhibited both the carbohydrate digestive enzymes (α-glucosidase and α-amylase) and aldose reductase, which are vital for the therapeutic control of postprandial hyperglycaemia. MeT was also found to have significant antioxidant activity. Using several spectroscopic approaches, the primary active component found in MeT was identified as gallic acid. With low Ki values, gallic acid significantly inhibited α-glucosidase (30.86 µg/mL) and α-amylase (6.50 µg/mL). Also, MeT and gallic acid both inhibited aldose reductase effectively, corresponding to an IC50 value of 3.31 and 3.05 µg/mL. Our findings imply that the presence of polyphenol compounds (identified via HPLC analysis) is more likely to be responsible for the antihyperglycaemic role exhibited by MeT via the inhibition of α-glucosidase and the polyol pathway. Further, gallic acid interacted with the key residues of the active sites of α-glucosidase (-6.4 kcal/mol), α-amylase (-5.8 kcal/mol) and aldose reductase (-5.8 kcal/mol) as observed in the protein-ligand docking. It was also predicted that gallic acid was stable inside the binding pockets of the target enzymes during molecular dynamics simulation. Overall, gallic acid derived from MeT via bioassay-guided isolation emerges as a natural antidiabetic drug and can be taken into in vivo and clinical studies shortly.Communicated by Ramaswamy H. Sarma.

Trans-(±)-TTPG-B Attenuates Cell Cycle Progression and Inhibits Cell Proliferation on Cholangiocarcinoma Cells

This research aimed to determine the target protein and molecular mechanism of trans-(±)-kusunokinin ((±)-KU) derivatives (trans-(±)-ARC and trans-(±)-TTPG-B). Molecular docking was used to predict potential synthesized (±)-KU targets among 22 proteins. The (±)-TTPG-B bound HSP90α better than EC44, native (±)-KU and (-)-KU, and (±)-KU and (-)-ARC. In contrast, (-)-ARC bound PI3K more strongly than any other test compound. CSF1R and AKR1B1 were not supposed to be the target of (±)-TTPG-B and (±)-ARC, unlike native (±)-KU. The (±)-TTPG-B bound Tyr139 and Trp162 of HSP90α. Moreover, (-)-ARC bound PI3K via hydrogen bonds and π-π stacking at distinct amino acids, which was different from the other tested compounds. Using half of the IC50 concentration, (±)-TTPG-B, (±)-KU and (±)-ARC enhanced cell cycle arrest at the G0/G1 phase after 12 h and 24 h on KKU-M213 (CCA) cells. The (±)-TTPG-B showed a stronger inhibitory effect than (±)-ARC and (±)-KU on HSP90α, PI3K, HSP90β, c-Myc, AKT, MEK1, CyclinB1, CyclinD1, and CDK1 for 24 and 48 h after treatment with the same concentration (0.015 µM). Thus, trans-(±)-TTPG-B, a newly synthesized compound, has pharmacological potential for development as a target therapy for CCA treatment.

Serum AKR1B10 as an indicator of unfavorable survival of hepatocellular carcinoma

BACKGROUND AND AIMS

A large-scale multicenter study validated aldo-keto reductase 1B10 (AKR1B10) as a new serum marker of hepatocellular carcinoma (HCC). This study aimed to evaluate the prognostic value of serum AKR1B10 in HCC.

METHODS

273 naïve HCC patients enrolled for serum AKR1B10 tests were followed up for 2 years. Survival and clinical data were collected. Kaplan-Meier survival analysis and log-rank tests were used to estimate correlation of patient survival with serum AKR1B10. Univariate and multivariate COX regression analyses were used to evaluate the prognostic value of serum AKR1B10 level independently or in combination with other clinicopathological factors. α-fetoprotein (AFP) was analyzed in parallel for comparison.

RESULTS

Serum AKR1B10 associated with tumor stage (p = 0.012), size (p = 0.004), primary tumor number (p = 0.019), and Child-Pugh classification (p = 0.003). HCC patients with a high level of serum AKR1B10 (≥ 267.9 pg/ml) had median survival (MS) of 25 months (95% confidence interval [CI] 20.788-29.212) vs. MS of 34 months (CI 28.911-39.089) in patients with normal serum AKR1B10 (p < 0.001). Univariate and multivariate COX regression analyses showed that serum AKR1B10 level was an unfavorable prognostic marker of HCC independently (HR 1.830, 95% CI 1.312-2.552; p < 0.001) or in combination with other clinical factors (HR 1.883, 95% CI 1.264-2.806; p = 0.002), such as TNM stage, tumor size and portal invasion. In the same cohort of HCC patients, AFP exhibited prognostic value at a cut-off of 400 ng/ml, but not at 20 ng/ml and 200 ng/ml.

CONCLUSIONS

Serum AKR1B10 is a new prognostic marker of HCC, better than AFP.

Aldose reductase and glutathione in senile cataract nucleus of diabetics and non-diabetics

PURPOSE

The aim is to evaluate the aldose reductase (AR) and glutathione (GSH) activity in the nucleus of senile cataract in type 2 diabetes and non-diabetic group of patients.

METHODS

A total of 62 patients including 31 diabetics and 31 non- diabetics who were undergoing cataract surgery were included. Nucleus extracted was sent for analysis of AR and GSH activity while blood sample was taken for glycated haemoglobin (HbA1c) levels.

STATISTICAL ANALYSIS

Data were analysed using IBM SPSS 25. Comparison was carried out by unpaired T-test and correlations were established by Pearson's correlation. The p value less than 0.05 was considered significant for all analyses.

STUDY DESIGN

This is a prospective cross-sectional comparative study.

RESULTS

In this study, diabetic group patients showed earlier progression of cataract as compared to the non-diabetic group (p-value 0.0310). Mean HbA1c in the diabetic group was 7.34% compared to the non-diabetic group of 5.7% (p value < 0.001). AR in the diabetic patients was 2.07 mU/mg while the non-diabetic group was 0.22 mU/mg (p-value < 0.001). GSH in the diabetic group was 3.38 μMol/g and the non-diabetic group was 7.47 μMol/g (p value < 0.001). HbA1c showed positive correlation with AR among the diabetic group (p-value 0.028).

CONCLUSION

Elevated oxidative stress can be strongly attributed to high AR and low GSH activity among the diabetic group as compared to the non-diabetic group and can lead to early cataract formation.

Swamp eel aldehyde reductase is involved in response to nitrosative stress via regulating NO/GSH levels

Aldehyde reductase (ALR) plays key roles in the detoxification of toxic aldehyde. In this study, the authors cloned the swamp eel ALR gene using rapid amplification of cDNA ends-PCR (RACE-PCR). The recombinant protein (rALR) was expressed in Escherichia coli and purified using a Ni2+ -NTA chelating column. The rALR protein exhibited efficient reductive activity towards several aldehydes, ketones and S-nitrosoglutathione (GSNO). A spot assay suggested that the recombinant E. coli strain expressing rALR showed better resistance to formaldehyde, sodium nitrite and GSNO stress, suggesting that swamp eel ALR is crucial for redox homeostasis in vivo. Consequently, the authors investigated the effect of rALR on the oxidative parameters of the liver in swamp eels challenged with Aeromonas hydrophila. The hepatic glutathione (GSH) content significantly increased, and the hepatic NO content and levels of reactive oxygen species and reactive nitrogen species significantly decreased when rALR was administered. In addition, the mRNA expression of hepatic Alr, HO1 and Nrf2 was significantly upregulated, whereas the expression levels of NF-κB, IL-1β and NOS1 were significantly downregulated in the rALR-administered group. Collectively, these results suggest that ALR is involved in the response to nitrosative stress by regulating GSH/NO levels in the swamp eel.

Cemtirestat, an aldose reductase inhibitor and antioxidant compound, induces ocular defense against oxidative and inflammatory stress in rat models for glycotoxicity

Fructose, endogenously produced as a consequence of activation of the polyol pathway under hyperglycemic conditions, contribute to formation of advanced glycoxidation end products (AGEs) and carbonyl stress. Oxidative stress is increased in diabetes (DM) due to AGEs formation and the utilization of NADPH by aldo-keto reductase, AKR1B1(AR), the first enzyme in polyol pathway. Since inhibition of AR is an attractive approach for the management of diabetic eye diseases, we aimed to compare the effects of a novel AR inhibitor (ARI)/antioxidant (AO) compound cemtirestat on eye tissues with the effects of ARI drug epalrestat and AO agent stobadine in rat model for glycotoxicity. One group of rats was fed high fructose (10% drinking water; 14 weeks), while type-2 DM was induced in the other group of rats with fructose plus streptozotocin (40 mg/kg-bw/day). Diabetic (D) and nondiabetic fructose-fed rats (F) were either untreated or treated with two different doses of cemtirestat (2.5 and 7.5 mg/kg-bw/day), epalrestat (25 and 50 mg/kg-bw/day), or stobadine (25 and 50 mg/kg-bw/day) for 14 weeks. Cemtirestat, epalrestat, and stobadine elaviate the increase in TNF-α, IL-1β, NF-ƙB, and caspase-3 in retina, lens, cornea, and sclera of F and D rats. Both glycotoxicity models resulted in a decrease in GSH to GSSG ratio and a change in glutathione S-transferase activity in eye tissues, but these alterations were improved especially with cemtirestat and stobadine. Lens D-sorbitol of D rats increased more than that of F rats, this increase was only attenuated by cemtirestat and epalrestat. Epalrestat was more effective than cemtirestat and stobadine in inhibiting the increase of vascular endothelial growth factor (VEGF) in the retina of F and D rats. Cemtirestat and stobadine but not epalrestat decreased high level of Nε-(carboxymethyl)lysine in the lens and retina of F and D rats. Cemtirestat is a potential therapeutic in protecting the rat eye against glycotoxicity insults.

Araucaria heterophylla oleogum resin essential oil is a novel aldose reductase and butyryl choline esterase enzymes inhibitor: in vitro and in silico evidence

The essential oil isolated by hydrodistillation of the oleogum resin of Araucaria heterophylla has been analyzed by GC-MS. Twenty-four components accounting to 99.89% of the total detected constituents of this essential oil were identified. The major ones were: caryophyllene oxide (14.8%), ( +)-sabinene (12.07%), D-limonene (11.22%), caryophyllene (10.36%), α-copaene (8.00%), β-pinene (6.44%), trans-verbenol (5.88%) and α-pinene oxide (5.18%). The in vitro inhibitory activities of this oil against aldose reductase, BuCHE, COX-2 and SARS-CoV-2 Mpro enzymes were evaluated. This revealed promising inhibitory activity of the essential oil against both aldose reductase and BuCHE enzymes. The molecular docking study of the major components of the Araucaria heterophylla essential oil was carried out to correlate their binding modes and affinities for aldose reductase and BuCHE enzymes with the in vitro results. In conclusion, the in vitro inhibitory activity of the essential oil attributed to the synergistic effect between its components and the in silico study suggested that compounds containing epoxide and hydroxyl groups may be responsible for this activity. This study is preliminary screening for the oil to be used as antidiabetic cataract and Alzheimer's disease therapeutics and further investigations may be required.

Construction and experimental validation of a macrophage cell senescence-related gene signature to evaluate the prognosis, immunotherapeutic sensitivity, and chemotherapy response in bladder cancer

Tumor-associated macrophages (TAMs) are pivotal components of tumor microenvironment (TME), and senescent TAMs contribute to the alternation of the profiles of TME. However, the potential biological mechanisms and the prognosis value of senescent macrophages are largely unknown, especially in bladder cancer (BLCA). Based on the single-cell RNA sequencing of a primary BLCA sample, 23 macrophage-related genes were identified. Genomic difference analysis, LASSO, and Cox regression were used to develop the risk model. TCGA-BLCA cohort (n = 406) was utilized as the training cohort, and then, three independent cohorts (n = 90, n = 221, n = 165) from Gene Expression Omnibus, clinical samples from the local hospital (n = 27), and in vitro cell experiments were used for external validation. Aldo-keto reductase family 1 member B (AKR1B1), inhibitor of DNA binding 1 (ID1), and transforming growth factor beta 1 (TGFB1I1) were determined and included in the predictive model. The model serves as a promising tool to evaluate the prognosis in BLCA (pooled hazard ratio = 2.51, 95% confidence interval = [1.43; 4.39]). The model was also effective for the prediction of immunotherapeutic sensitivity and chemotherapy treatment outcomes, which were further confirmed by IMvigor210 cohort (P < 0.01) and GDSC dataset, respectively. Twenty-seven BLCA samples from the local hospital proved that the risk model was associated with the malignant degree (P < 0.05). At last, the human macrophage THP-1 and U937 cells were treated with H2O2 to mimic the senescent process in macrophage, and the expressions of these molecules in the model were detected (all P < 0.05).Overall, a macrophage cell senescence-related gene signature was constructed to predict the prognosis, immunotherapeutic response, and chemotherapy sensitivity in BLCA, which provides novel insights to uncover the underlying mechanisms of macrophage senescence.

Comparative anti-Diabetic potential of phytocompounds from Dr. Duke's phytochemical and ethnobotanical database and standard antidiabetic drugs against diabetes hyperglycemic target proteins: an in silico validation

In the current investigation, the antidiabetic potential of 40 phytocompounds from Dr. Dukes phytochemical and ethanobotanical database and three antidiabetic pharmaceuticals from the market comparatively validated against hyperglycemic target proteins. Silymarin, proanthocyanidins, merremoside, rutin, mangiferin-7-O-beta-glucoside, and gymnemic acid exhibited good binding affinity toward protein targets of diabetes among the 40 phytocompounds from Dr.Dukes database over three chosen antidiabetic pharmaceutical compounds. Further these phytocompounds and sitagliptin are validated for its ADMET and bioactivity score to screen its pharmacological and pharmacokinetics properties. Silymarin, proanthocyanidins, rutin along with sitagliptin screened for DFT analysis found that phytocompounds have great Homo-Lumo orbital energies over commercial pharmaceutical sitagliptin. Finally, four complexes of alpha amylase-silymarin, alpha amylase-sitagliptin, aldose reductase-proanthocyanidins, and aldose reductase-sitagliptin screened for MD simulation and MMGBSA analysis, results shown that the phytocompounds silymarin and proanthocyanidins have strong affinities for binding to the binding pockets of alpha amylase and aldose reductase respectively over antidiabetic pharmaceuticals. Our current study proven proanthocyanidins and silymarin act as novel antidiabetic compounds toward diabetic target protein but it require clinical trial to evaluate its clinical pertinence toward diabetic target proteins.Communicated by Ramaswamy Sarma.

Sortase E-mediated site-specific immobilization of green fluorescent protein and xylose dehydrogenase on gold nanoparticles

Sortase, a bacterial transpeptidase enzyme, is an attractive tool for protein engineering due to its ability to break a peptide bond at a specific site and then reform a new bond with an incoming nucleophile. Here, we present the immobilization of two recombinant proteins, enhanced green fluorescent protein (eGFP) and xylose dehydrogenase (XylB) over triglycine functionalized PEGylated gold nanoparticles (AuNPs) using C. glutamicum sortase E. For the first time, we used a new class of sortase from a non-pathogenic organism for sortagging. The site-specific conjugation of proteins with LAHTG-tagged sequences on AuNPs via covalent cross-linking was successfully detected by surface-enhanced Raman scattering (SERS) and UV-vis spectral analysis. The sortagging was initially validated by an eGFP model protein and later with the xylose dehydrogenase enzyme. The catalytic activity, stability, and reusability of the immobilized XylB were studied with the bioconversion of xylose to xylonic acid. When compared to the free enzyme, the immobilized XylB was able to retain 80% of its initial activity after four sequential cycles and exhibited no significant variations in instability after each cycle for about 72h. These findings suggest that C. glutamicum sortase could be useful for immobilizing site-specific proteins/enzymes in biotransformation applications for value-added chemical production.

Expression of AKRs superfamily and prognostic in human gastric cancer

The human aldo-keto reductase (AKRs) superfamily is involved in the development of various tumors. However, the different expression patterns of AKRs and their prognostic value in gastric cancer (GC) have not been clarified. In this study, we analyzed the gene expression and gene methylation level of AKRs in GC patients and the survival data and immune infiltration based on AKRs expression, using data from different databases. We found that the expression levels of AKR1B10, AKR1C1, AKR1C2, and AKR7A3 in GC tissues were lower and the expression level of AKR6A5 was higher in GC tissues than in normal tissue. These differentially expressed genes (AKR1B10, AKR1C1, AKR1C2, AKR7A3, and AKR6A5) were significantly correlated with the infiltration level. The expression of SPI1 and AKR6A5 in GC was positively correlated. Survival analysis showed that GC levels of AKR6A5 reduced or increased mRNA levels of AKR7A3, and AKR1B10 was expected to have higher overall survival (OS), first progression (FP) survival, and postprogression survival (PPS) rates and a better prognosis. Moreover, the expression of AKR1B1 was found to be correlated with the staging of GC. The methylation of AKR6A5 (KCNAB2) at cg05307871 and cg01907457 was significantly associated with the classification of GC. Meta-analysis and ROC curve analysis show that the expression level of AKR1B1 and the methylation of cg16156182 (KCNAB1), cg11194299 (KCNAB2), cg16132520 (AKR1B1), and cg13801416 (AKR1B1) had a high hazard ratio and a good prognostic value. These data suggest that the expression and methylation of AKR1B1 and AKR6A5 are significantly related to the prognosis.

Metabolic Hijacking of Hexose Metabolism to Ascorbate Synthesis Is the Unifying Biochemical Basis of Murine Liver Fibrosis

We wished to understand the metabolic reprogramming underlying liver fibrosis progression in mice. Administration to male C57BL/6J mice of the hepatotoxins carbon tetrachloride (CCl4), thioacetamide (TAA), or a 60% high-fat diet, choline-deficient, amino-acid-defined diet (HF-CDAA) was conducted using standard protocols. Livers collected at different times were analyzed by gas chromatography-mass spectrometry-based metabolomics. RNA was extracted from liver and assayed by qRT-PCR for mRNA expression of 11 genes potentially involved in the synthesis of ascorbic acid from hexoses, Gck, Adpgk, Hk1, Hk2, Ugp2, Ugdh, Ugt1a1, Akr1a4, Akr1b3, Rgn and Gulo. All hepatotoxins resulted in similar metabolic changes during active fibrogenesis, despite different etiology and resultant scarring pattern. Diminished hepatic glucose, galactose, fructose, pentose phosphate pathway intermediates, glucuronic acid and long-chain fatty acids were compensated by elevated ascorbate and the product of collagen prolyl 4-hydroxylase, succinate and its downstream metabolites fumarate and malate. Recovery from the HF-CDAA diet challenge (F2 stage fibrosis) after switching to normal chow was accompanied by increased glucose, galactose, fructose, ribulose 5-phosphate, glucuronic acid, the ascorbate metabolite threonate and diminished ascorbate. During the administration of CCl4, TAA and HF-CDAA, aldose reductase Akr1b3 transcription was induced six- to eightfold, indicating increased conversion of glucuronic acid to gulonic acid, a precursor of ascorbate synthesis. Triggering hepatic fibrosis by three independent mechanisms led to the hijacking of glucose and galactose metabolism towards ascorbate synthesis, to satisfy the increased demand for ascorbate as a cofactor for prolyl 4-hydroxylase for mature collagen production. This metabolic reprogramming and causal gene expression changes were reversible. The increased flux in this pathway was mediated predominantly by increased transcription of aldose reductase Akr1b3.

Exploration of the Mechanism of Kaempferol in the Treatment of Cervical Cancer-based on Metabolomics and Network Pharmacology

BACKGROUND

Cervical cancer is a prevalent malignancy among women globally.

OBJECTIVE

We aimed to uncover the mechanism of action of kaempferol in the treatment of cervical cancer using an integrated approach that combines metabolomics with network pharmacology.

METHODS

Initially, we investigated the specific metabolites and potential pathways influenced by kaempferol in the pathological progression of cervical cancer, employing UHPLC-Q-Orbitrap MS metabolomics. In addition, network pharmacology analysis was performed to ascertain the pivotal targets of kaempferol in the context of CC therapy.

RESULTS

Metabolomics analysis indicated that the therapeutic effect of kaempferol on cervical cancer is primarily associated with 11 differential metabolites and 7 metabolite pathways. These pathways include arginine and proline metabolism, the tricarboxylic acid cycle, phenylalanine, tyrosine, and tryptophan biosynthesis, fatty acid biosynthesis, glycerophospholipid metabolism, pantothenate and CoA biosynthesis, and tyrosine metabolism. Additionally, kaempferol was found to regulate 3 differential metabolites, namely palmitic acid, citric acid, and L-tyrosine, by directly targeting 7 specific proteins, including AKR1B1, CS, EGFR, PLA2G1B, PPARG, SLCO2B1, and SRC. Furthermore, molecular docking demonstrated strong binding affinities between kaempferol and 7 crucial targets.

CONCLUSION

This study elucidates the intricate mechanisms by which kaempferol acts against cervical cancer. Furthermore, this research offers a novel approach to investigating the potential pharmacological mechanisms of action exhibited by natural compounds.

Phytochemical Composition and In Vitro Antioxidant, Anti-Inflammatory, Anticancer, and Enzyme-Inhibitory Activities of Artemisia nilagirica (C.B. Clarke) Pamp

Plants have been employed in therapeutic applications against various infectious and chronic diseases from ancient times. Various traditional medicines and folk systems have utilized numerous plants and plant products, which act as sources of drug candidates for modern medicine. Artemisia is a genus of the Asteraceae family with more than 500 species; however, many of these species are less explored for their biological efficacy, and several others are lacking scientific explanations for their uses. Artemisia nilagirica is a plant that is widely found in the Western Ghats, Kerala, India and is a prominent member of the genus. In the current study, the phytochemical composition and the antioxidant, enzyme-inhibitory, anti-inflammatory, and anticancer activities were examined. The results indicated that the ethanol extract of A. nilagirica indicated in vitro DPPH scavenging (23.12 ± 1.28 µg/mL), ABTS scavenging (27.44 ± 1.88 µg/mL), H2O2 scavenging (12.92 ± 1.05 µg/mL), and FRAP (5.42 ± 0.19 µg/mL). The anti-inflammatory effect was also noticed in the Raw 264.7 macrophages, where pretreatment with the extract reduced the LPS-stimulated production of cytokines (p < 0.05). A. nilagirica was also efficient in inhibiting the activities of α-amylase (38.42 ± 2.71 µg/mL), α-glucosidase (55.31 ± 2.16 µg/mL), aldose reductase (17.42 ± 0.87 µg/mL), and sorbitol dehydrogenase (29.57 ± 1.46 µg/mL). It also induced significant inhibition of proliferation in breast (MCF7 IC50 = 41.79 ± 1.07, MDAMB231 IC50 = 55.37 ± 2.11µg/mL) and colon (49.57 ± 1.46 µg/mL) cancer cells. The results of the phytochemical screening indicated a higher level of polyphenols and flavonoids in the extract and the LCMS analysis revealed the presence of various bioactive constituents including artemisinin.

Prognosis and tumor immune microenvironment of patients with gastric cancer by a novel senescence-related signature

BACKGROUND

Cellular senescence is a stable state of cell cycle arrest that plays a crucial role in the tumor microenvironment (TME) and cancer progression. Nevertheless, the accurate prognosis of gastric cancer (GC) is complicated to predict due to tumor heterogeneity. The work aimed to build a novel prognostic model in GC.

METHODS

LASSO and Cox regression analysis were constructed to develop a prognostic senescence-related signature. The Gene Expression Omnibus dataset was used for external validation of signature. Afterward, we performed correlation analysis for the risk score and the infiltrating abundance of immune cells, TME scores, drug response, tumor mutational burden (TMB), and immunotherapy efficacy.

RESULTS

Five senescence-related genes (AKR1B1, CTNNAL1, DUSP16, PLA2R1, and ZFP36) were screened to build a signature. The high-risk group had a shorter overall survival, cancer-specific survival, and progression-free survival when compared to the low-risk group. We further constructed a nomogram based on risk score and clinical traits, which can predict the prognosis of GC patients more accurately. Moreover, the risk score was evidently correlated with infiltration of immune cells, TME score, TMB, TIDE score, and chemotherapy sensitivity. Meanwhile, the Kyoto Encyclopedia of Genes and Genomes pathway showed that the PI3K-Akt and Wnt signaling pathway were differentially enriched in the high-risk group.

CONCLUSIONS

The senescence-related signature was an accurate tool to guide the prognosis and might promote the progress of personalized treatment.

Screening inhibitory effects of selected flavonoids on human recombinant aldose reductase enzyme: in vitro and in silico study

Aldose reductase (AR) is the first enzyme of the polyol pathway that has physiological importance under hyperglycaemic conditions. The article has been focussed on AR enzyme inhibition by selected compounds. For this purpose, the in vitro inhibitory effects of various compounds on commercially available recombinant human AR (rAR) enzyme activity were investigated. The IC₅₀ values of compounds on rAR inhibition effect were found for 6-hydroxy flavone, syringic acid, diosmetin, 6-fluoroflavone, 7-hydroxy-4'-nitroisoflavone, myricetin as 2.05, 2.97, 15.75, 16.1, 49.5, and 63 µM, respectively. 6-Hydroxy flavone and syringic acid competitively inhibited rAR with respect to the NADPH with K_i values 0.509 ± 0.036 and 0.842 ± 0.012 µM. In addition, docking studies were performed to evaluate the potential enzyme binding positions of the compounds. Our in vitro and in silico results indicated that the 6-hydroxy flavone may be a good lead compound in the development of AR inhibitors to prevent diabetic complications.

Negative Effects of Chronic High Intake of Fructose on Lung Diseases

In the modern diet, excessive fructose intake (>50 g/day) had been driven by the increase, in recent decades, of the consumption of sugar-sweetened beverages. This phenomenon has dramatically increased within the Caribbean and Latin American regions. Epidemiological studies show that chronic high intake of fructose related to sugar-sweetened beverages increases the risk of developing several non-communicable diseases, such as chronic obstructive pulmonary disease and asthma, and may also contribute to the exacerbation of lung diseases, such as COVID-19. Evidence supports several mechanisms—such as dysregulation of the renin−angiotensin system, increased uric acid production, induction of aldose reductase activity, production of advanced glycation end-products, and activation of the mTORC1 pathway—that can be implicated in lung damage. This review addresses how these pathophysiologic and molecular mechanisms may explain the lung damage resulting from high intake of fructose.

Phyto-Computational Intervention of Diabetes Mellitus at Multiple Stages Using Isoeugenol from Ocimum tenuiflorum: A Combination of Pharmacokinetics and Molecular Modelling Approaches

In the present study, the anti-diabetic potential of Ocimum tenuiflorum was investigated using computational techniques for α-glucosidase, α-amylase, aldose reductase, and glycation at multiple stages. It aimed to elucidate the mechanism by which phytocompounds of O. tenuiflorum treat diabetes mellitus using concepts of druglikeness and pharmacokinetics, molecular docking simulations, molecular dynamics simulations, and binding free energy studies. Isoeugenol is a phenylpropene, propenyl-substituted guaiacol found in the essential oils of plants. During molecular docking modelling, isoeugenol was found to inhibit all the target enzymes, with a higher binding efficiency than standard drugs. Furthermore, molecular dynamic experiments revealed that isoeugenol was more stable in the binding pockets than the standard drugs used. Since our aim was to discover a single lead molecule with a higher binding efficiency and stability, isoeugenol was selected. In this context, our study stands in contrast to other computational studies that report on more than one compound, making it difficult to offer further analyses. To summarize, we recommend isoeugenol as a potential widely employed lead inhibitor of α-glucosidase, α-amylase, aldose reductase, and glycation based on the results of our in silico studies, therefore revealing a novel phytocompound for the effective treatment of hyperglycemia and diabetes mellitus.

Electrochemical Biosensing of Glucose Based on the Enzymatic Reduction of Glucose

In this work, the enzyme aldehyde reductase, also known as aldose reductase, was synthesized and cloned from a human gene. Spectrophotometric measurements show that in presence of the nicotinamide adenine dinucleotide phosphate cofactor (NADPH), the aldehyde reductase catalyzed the reduction of glucose to sorbitol. Electrochemical measurements performed on an electrodeposited poly(methylene green)-modified gold electrode showed that in the presence of the enzyme aldehyde reductase, the electrocatalytic oxidation current of NADPH decreased drastically after the addition of glucose. These results demonstrate that aldehyde reductase is an enzyme that allows the construction of an efficient electrochemical glucose biosensor based on glucose reduction.

Moving toward a new horizon for the aldose reductase inhibitor epalrestat to treat drug-resistant cancer

Epalrestat (EPA) is a potent inhibitor of aldose reductases AKR1B1 and AKR1B10, used for decades in Japan for the treatment of diabetic peripheral neuropathy. This orally-active, brain-permeable small molecule, with a relatively rare and essential 2-thioxo-4-thiazolidinone motif, functions as a regulator intracellular carbonyl species. The repurposing of EPA for the treatment of pediatric rare diseases, brain disorders and cancer has been proposed. A detailed analysis of the mechanism of action, and the benefit of EPA to combat advanced malignancies is offered here. EPA has revealed marked anticancer activities, alone and in combination with cytotoxic chemotherapy and targeted therapeutics, in experimental models of liver, colon, and breast cancers. Through inhibition of AKR1B1 and/or AKR1B10 and blockade of the epithelial-mesenchymal transition, EPA largely enhances the sensitivity of cancer cells to drugs like doxorubicin and sorafenib. EPA has revealed a major anticancer effect in an experimental model of basal-like breast cancer and clinical trials have been developed in patients with triple-negative breast cancer. The repurposing of the drug to treat chemo-resistant solid tumors seems promising, but more studies are needed to define the best trajectory for the positioning of EPA in oncology.

Some sulfonamides as aldose reductase inhibitors: therapeutic approach in diabetes

In this study, aldose reductase (AR) was purified from sheep kidney using chromatographic methods and examined the interactions between some sulfonamides and the enzyme. According to results, sulfonamides display effective inhibitor features for sheep kidney AR with IC₅₀ values in the range of 37.27-87.65 μM and K_is in the range of 25.72 ± 6.45 to 73.56 ± 17.49 μM. The sulfonamides displayed different inhibition mechanisms. It was found that studied all compounds displayed non-competitive inhibition type except for 5-chlorothiophene-2-sulfonamide (1). It showed competitive inhibition. Among these compounds, 2,5-dichlorothiophene-3-sulfonamide compound (2) was showed the most potent AR inhibitor (K_i: 25.72 ± 6.45). These compounds may be useful in the treatment of diabetic complications.

Neuroprotective effects of oleuropein on retina photoreceptors cells primary culture and olive leaf extract and oleuropein inhibitory effects on aldose reductase in a diabetic model: Meriones shawi

Aldose reductase (AR) is an enzyme implicated in the development of diabetes complications among them diabetic retinopathy. Erythrocyte AR activity was measured in control and diabetic Meriones shawi, a type-2 diabetic model. We noticed an increase of AR activity in diabetic Meriones by comparison to controls. Olive leaf aqueous extract and oleuropein were tested for their inhibitory potential on AR activity. Both exerted a partial in-vitro inhibition effect which was higher with the olive leaf extract. The ex-vivo protective effect of oleuropein was tested in photoreceptors rod and Mcône retinal cells of Meriones shawi in hyperglycaemic conditions. Mixed retinal cells were cultured at 25 mM glucose for 5 days and treated with oleuropein. Cell viability was assessed using MTT test and trypan blue exclusion dye. Rod and Mcône Photoreceptors were characterised by immuno-cytochemistry. Oleuropein protected retinal cells against the toxic effect of glucose by improving the viability of photoreceptors.

An evolutionary conserved detoxification system for membrane lipid-derived peroxyl radicals in Gram-negative bacteria

How double-membraned Gram-negative bacteria overcome lipid peroxidation is virtually unknown. Bactericidal antibiotics and superoxide ion stress stimulate the transcription of the Burkholderia cenocepacia bcnA gene that encodes a secreted lipocalin. bcnA gene orthologs are conserved in bacteria and generally linked to a conserved upstream gene encoding a cytochrome b561 membrane protein (herein named lcoA, lipocalin-associated cytochrome oxidase gene). Mutants in bcnA, lcoA, and in a gene encoding a conserved cytoplasmic aldehyde reductase (peroxidative stress-associated aldehyde reductase gene, psrA) display enhanced membrane lipid peroxidation. Compared to wild type, the levels of the peroxidation biomarker malondialdehyde (MDA) increase in the mutants upon exposure to sublethal concentrations of the bactericidal antibiotics polymyxin B and norfloxacin. Microscopy with lipid peroxidation-sensitive fluorescent probes shows that lipid peroxyl radicals accumulate at the bacterial cell poles and septum and peroxidation is associated with a redistribution of anionic phospholipids and reduced antimicrobial resistance in the mutants. We conclude that BcnA, LcoA, and PsrA are components of an evolutionary conserved, hitherto unrecognized peroxidation detoxification system that protects the bacterial cell envelope from lipid peroxyl radicals.

Phosphoproteome of signaling by ErbB2 in ovarian cancer cells

The gene for receptor tyrosine kinase ErbB2 is amplified in breast and ovarian tumours. The linear pathway by which signals are transduced through ErbB2 are well known. However, second generation questions that address spatial aspects of signaling remain. To address this, we have undertaken a mass spectrometry approach to identify phosphoproteins specific for ErbB2 using the inhibitors Lapatinib and CP724714 in ovarian cancer cells. The ErbB2 specific proteins identified in SKOV-3 cells were Myristoylated alanine-rich C-kinase substrate, Protein capicua homolog, Protein peptidyl isomerase G, Protein PRRC2C, Chromobox homolog1 and PRP4 homolog. We have evaluated three phosphoproteins PKM2, Aldose reductase and MARCKS in SKOV-3 cells. We observed that PKM2 was phosphorylated by EGF but was not inhibited by Lapatinib and CP724714. The activity of aldose reductase in reducing NADPH as a substrate was significantly higher in EGF stimulated cells which was inhibited by Lapatinib and CP724714 but not by Geftinib (EGFR inhibitor). MARCKS was phosphorylated on stimulation of SKOV-3 cells with EGF that was inhibited by Lapatinib and CP724714 which was dependent on the kinase activity of ErbB2. These results have identified phosphoproteins that are specific to ErbB2 which have not been previously reported and sets the basis for future experiments.

Herbal Phytomedicine 'Irisolidone' in Chronic Diseases: Biological Efficacy and Pharmacological Activity

BACKGROUND

Plant-derived products have been used in medicine as a source of bioactive molecules, mainly due to their medicinal importance and therapeutic potential. Nowadays, plant derived products have been used in the medicine for the development of novel drug leads. Polyphenols are an important class of secondary metabolites found to be present in plants and their derived products. Polyphenols play an important role in the nutrition of human beings and also have a significant role in plant resistance against pests and diseases. Scientific studies have proven the biological importance of flavonoids in medicine and other allied health sectors. Anti-oxidant, analgesic, anti-microbial, anti-inflammatory, anti-viral, anti-tumor and anti-allergic activities are the important pharmacological features of flavonoids. Irisolidone is an important isoflavone found to be present in Pueraria lobata flowers.

METHODS

To know the medicinal importance and therapeutic potential of irisolidone in the medicine, numerous scientific research data have been collected from Google, Google Scholar, PubMed, Science Direct, and Scopus. Pharmacological activity data of irisolidone has been collected and analyzed in the present works to know their health beneficial aspects in the medicine. Detailed pharmacological activities of irisolidone have been investigated through scientific data analysis of scientific research works.

RESULTS

Scientific research data analysis of irisolidone revealed the anti-inflammatory, antiangiogenic, anti-cancer, anti-platelet, anti-oxidant, anti-hyperlipidemic, immunomodulating, hepatoprotective and estrogenic potential. However, the biological effect of irisolidone on the gastric system, aldose reductase enzymes, malignant gliomas, and JC virus has also been investigated. Scientific data analysis revealed the significance of analytical tools for the separation and identification of irisolidone.

CONCLUSION

Present work signified the biological importance and therapeutic potential of irisolidone in medicine.

Prevention of tubulin/aldose reductase association delays the development of pathological complications in diabetic rats

In recent studies, we found that compounds derived from phenolic acids (CAFs) prevent the formation of the tubulin/aldose reductase complex and, consequently, may decrease the occurrence or delay the development of secondary pathologies associated with aldose reductase activation in diabetes mellitus. To verify this hypothesis, we determined the effect of CAFs on Na⁺,K⁺-ATPase tubulin-dependent activity in COS cells, ex vivo cataract formation in rat lenses and finally, to evaluate the antidiabetic effect of CAFs, diabetes mellitus was induced in Wistar rats, they were treated with different CAFs and four parameters were determinates: cataract formation, erythrocyte deformability, nephropathy and blood pressure. After confirming that CAFs are able to prevent the association between aldose reductase and tubulin, we found that treatment of diabetic rats with these compounds decreased membrane-associated acetylated tubulin, increased NKA activity, and thus reversed the development of four AR-activated complications of diabetes mellitus determined in this work. Based on these results, the existence of a new physiological mechanism is proposed, in which tubulin is a key regulator of aldose reductase activity. This mechanism can explain the incorrect functioning of aldose reductase and Na⁺,K⁺-ATPase, two key enzymes in the pathogenesis of diabetes mellitus. Moreover, we found that such alterations can be prevented by CAFs, which are able to dissociate tubulin/aldose reductase complex.

In Stallion Spermatozoa, Superoxide Dismutase (Cu-Zn) (SOD1) and the Aldo-Keto-Reductase Family 1 Member b (AKR1B1) Are the Proteins Most Significantly Reduced by Cryopreservation

Although cryopreservation is widely used in animal breeding, the technique is still suboptimal. The population of spermatozoa surviving the procedure experiences changes attributed to alteration in their redox regulation. In order to expand our knowledge regarding this particular aspect, the proteome in fresh and frozen thawed aliquots of equine spermatozoa was studied to identify the proteins most severely affected by the procedure. If alteration of redox regulation is a major factor explaining cryodamage, proteins participating in redox regulation should be principally affected. Using a split sample design, 30 ejaculates from 10 different stallions were analyzed as fresh spermatozoa, and another aliquot from the same ejaculate was analyzed as a frozen thawed sample. The proteome was studied under both conditions using UHPLC-MS/MS and bioinformatic analysis conducted to identify discriminant variables between both conditions. Data are available through the ProteomeXchange Consortium with identifier PXD022236. The proteins most significantly reduced were Aldo-keto reductase family 1 member B (p = 2.2 × 10-17) and Superoxide dismutase (Cu-Zn) (p = 4.7 × 10-14). This is the first time that SOD1 has been identified as a discriminating variable using bioinformatic analysis, where it was one of the most highly significantly different proteins seen between fresh and frozen thawed semen. This finding strongly supports the theory that alteration in redox regulation and oxidative stress is a major factor involved in cryodamage and suggests that control of redox regulation should be a major target to improve current cryopreservation procedures.

ER stress-induced adipocytes secrete-aldo-keto reductase 1B7-containing exosomes that cause nonalcoholic steatohepatitis in mice

Nonalcoholic steatohepatitis (NASH) is an increasingly prevalent liver disease linked to obesity and associated complications. Endoplasmic reticulum (ER) stress provokes dysfunction in lipid metabolism, which often leads to a progression of obesity-induced hepatic steatosis to NASH. However, the underlying mechanisms in which ER stress in adipose tissue induces hepatic pathology remain elusive. Here, we used male C57BL/6J mice to develop an animal model of NASH induced by a high fat (HFD) diet and methionine- and choline-deficient (MCD) diets. Using a gene-silencing approach with a recombinant lentiviral vector and extensive LC-MS/MS-based proteomics and lipidomics, we demonstrate that the ER stress-induced adipocyte-secreted exosome (ATEx) orchestrates lipid dynamics in the liver. We also noted that ATEx causes hepatic steatosis, inflammation, and fibrosis that lead to NASH through initial accumulation of glycerol and triglycerides in hepatocytes. We also determined that aldo-keto-reductase 1B7 (Akr1b7), a key mediator in liver lipid metabolism, is involved in ATEx-mediated NASH induction. Of note, Akr1b7 deficiency in ER stress-induced ATEx strongly protected the murine liver against HFD and MCD-induced NASH. Our results indicated that ER stress-induced, adipocyte-secreted ATEx triggers NASH by delivering exosomal AKR1B7 to, and elevating glycerol level, in hepatocytes. These findings suggest potential therapeutic strategie that target ATEx to prevent or manage obesity-induced NASH.

Isoliquiritigenin protects against angiotensin II-induced fibrogenesis by inhibiting NF-κB/PPARγ inflammatory pathway in human Tenon's capsule fibroblasts

PURPOSE

To examine the protective effects of Isoliquiritigenin (ISL) in angiotensin II (ANG II)-induced inflammation and fibrosis on Human Tenon's capsule Fibroblasts (HTFs) and Mouse Peritoneal Macrophages (MPMs). This study also investigated the potential mechanism of action of ISL.

METHOD

Methyl-thiazolyl tetrazolium (MTT) assay was used to test ISL toxicity. An ELISA and an RT-qPCR assay detected the inflammatory cytokines (TNF-α, IL-6, COX-2, and ICAM-1). A Western blot investigated the expression levels of inflammation-related signals [nuclear factor-κB (NF-κB), peroxisome proliferator-activated receptor γ (PPARγ)], and fibrogenesis, including fibronectin and alpha-smooth muscle actin (α-SMA)]. Protein expressions of α-SMA were measured by immunofluorescence.

RESULTS

Pre-treatment with ISL (10 or 20 μM) dose-dependently decreased the mRNA levels of TNF-α, IL-6, ICAM-1, and COX-2 induced by ANG II (1 μg/ml) in both MPMs and HTFs. ANG II remarkably increased the amount of P65 in the nuclei and decreased the amount of P65 in the cytoplasm. Additionally, ANG II reduced PPARγ expression levels in a time-dependent manner. Furthermore, these effects which were induced by ISL were remarkably neutralized by ISL pre-treatment. Finally, ANG II markedly elevated the expression of fibronectin and α-SMA.

CONCLUSION

ISL could alleviate ANG II-induced fibrogenesis by inhibiting the NF-κB/PPARγ inflammatory pathway. In addition, ISL may be a potential agent for the treatment of conjunctival fibrosis. Most importantly, the NF-κB/PPARγ signaling pathway could be an effective therapeutic target for the prevention and treatment of conjunctival fibrosis after glaucoma surgery.

[AKR1B10 promotes proliferation of breast cancer cells by activating Wnt/β-catenin pathway]

Objective To investigate the effect of aldosterone reductase family 1 member B10 (AKR1B10) on breast cancer cell proliferation and its mechanism. Methods AKR1B10 was overexpressed in MCF-7 cells and knocked down in BT-20 cells to establish both AKR1B10 overexpression and knockdown cell lines. The effect of AKR1B10 overexpression and knockdown on breast cancer cell proliferation was examined by CCK-8 assay. Real-time quantitative PCR was performed to detect AKR1B10 mRNA levels in breast cancer tissues and paired normal tissues. Western blot analysis was used to determine the protein levels of AKR1B10, β-catenin, cyclin D1, survivin, c-myc in breast cancer tissues and AKR1B10 overexpression/knockdown breast cancer cell lines. Results The expression of AKR1B10 was higher in breast cancer tissues. With AKR1B10 overexpression in MCF-7 cells, cell proliferation was promoted, and the expression levels of β-catenin, cyclin D1, c-myc and survivin were elevated. Meanwhile, knockdown of AKR1B10 in BT-20 breast cancer cells reduced cell proliferation and the expression levels of β-catenin, cyclin D1, c-myc and survivin. Conclusion AKR1B10 is highly expressed in breast cancer and promotes breast cancer cell proliferation by activating Wnt/β-catenin signaling pathway.

Immobilization of recombinant Escherichia coli whole cells harboring xylose reductase and glucose dehydrogenase for xylitol production from xylose mother liquor

In this study, recombinant E. coli BL21(DE3)/pCDFDuet-1-XR-GDH harboring xylose reductase (XR) and glucose dehydrogenase (GDH) were immobilized and applied for the production of xylitol from xylose mother liquor (XML). Various immobilization methods were screened and the cross-linking approach with diatomite and polyetherimide as the raw materials and glutaraldehyde as the cross-linking agent was the optimal one, and the recovery activity reached of 80.3% after immobilization. The half-life of immobilized cells was 1.52 times to that of free cells. Batch experiments showed that the enzyme activity of immobilized cells remained 70.5% of the initial activity after 10 batches and the space-time yield of xylitol reached of 11.5 g/(L h). The production of xylitol from xylose mother liquor by immobilized E. coli cells containing xylose reductase and glucose dehydrogenase was reported for the first time, which paved a foundation for industrial production of xylitol from waste xylose mother liquor.

Construction of efficient xylose-fermenting Saccharomyces cerevisiae through a synthetic isozyme system of xylose reductase from Scheffersomyces stipitis

Engineered Saccharomyces cerevisiae has been used for ethanol production from xylose, the abundant sugar in lignocellulosic hydrolyzates. Development of engineered S. cerevisiae able to utilize xylose effectively is crucial for economical and sustainable production of fuels. To this end, the xylose-metabolic genes (XYL1, XYL2 and XYL3) from Scheffersomyces stipitis have been introduced into S. cerevisiae. The resulting engineered S. cerevisiae strains, however, often exhibit undesirable phenotypes such as slow xylose assimilation and xylitol accumulation. This work was undertaken to construct an improved xylose-fermenting strain by developing a synthetic isozyme system of xylose reductase (XR). The DXS strain having both wild XR and mutant XR showed low xylitol accumulation and fast xylose consumption compared to the engineered strains expressing only one type of XRs, resulting in improved ethanol yield and productivity. These results suggest that the introduction of the XR-based synthetic isozyme system is a promising strategy to develop efficient xylose-fermenting strains.

Purification and Characterization of a Yeast Carbonyl Reductase for Synthesis of Optically Active (R)-Styrene Oxide Derivatives

Optically active styrene oxide derivatives are versatile chiral building blocks. Stereoselective reduction of phenacyl halide to chiral 2-halo-1-phenylethanol is the key reaction of the most economical synthetic route. Rhodotorula glutinis var. dairenensis IFO415 was discovered on screening as a potent microorganism reducing a phenacyl halide to the (R)-form of the corresponding alcohol. An NADPH-dependent carbonyl reductase was purified to homogeneity through four steps from this strain. The relative molecular mass of the enzyme was estimated to be 40,000 on gel filtration and 30,000 on SDS-polyacrylamide gel electrophoresis. This enzyme reduced a broad range of carbonyl compounds in addition to phenacyl halides. Some properties of the enzyme and preparation of a chiral styrene oxide using the crude enzyme are reported herein.

Production of (3S)-acetoin from diacetyl by using stereoselective NADPH-dependent carbonyl reductase and glucose dehydrogenase

Production of (3S)-acetoin ((3S)-AC), an important platform chemical, is desirable but difficult to perform. An NADPH-dependent carbonyl reductase (Gox0644) from Gluconobacter oxydans DSM 2003 was confirmed to have a good ability to reduce diacetyl (DA) to produce (3S)-AC. In this work, the NADPH-dependent carbonyl reductase was expressed and purified. Glucose dehydrogenase from Bacillus subtilis 168 was coupled with the NADPH-dependent carbonyl reductase to produce (3S)-AC from DA. Under the optimal conditions, 12.2 g l(-1) (3S)-AC was produced from 14.3 g l(-1) DA in 75 min. Because DA can be biotechnological produced, the two-enzymes coupling system might be a promising alternative for the (3S)-AC production.

Metabolism of ginger component [6]-shogaol in liver microsomes from mouse, rat, dog, monkey, and human

SCOPE

There are limited data on the metabolism of [6]-shogaol (6S), a major bioactive component of ginger. This study demonstrates metabolism of 6S in liver microsomes from mouse, rat, dog, monkey, and human.

METHODS AND RESULTS

The in vitro metabolism of 6S was compared among five species using liver microsomes from mouse, rat, dog, monkey, and human. Following incubations with 6S, three major reductive metabolites 1-(4'-hydroxy-3'-methoxyphenyl)-4-decen-3-ol (M6), 1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-ol (M9), and 1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-one (M11), as well as two new oxidative metabolites (1E,4E)-1-(4'-hydroxy-3'-methoxyphenyl)-deca-1,4-dien-3-one (M14) and (E)-1-(4'-hydroxy-3'-methoxyphenyl)-dec-1-en-3-one (M15) were found in all species. The kinetic parameters of M6 in liver microsomes from each respective species were quantified using Michaelis-Menten theory. A broad CYP-450 inhibitor, 1-aminobenzotriazole, precluded the formation of oxidative metabolites, M14 and M15, and 18β-glycyrrhetinic acid, an aldo-keto reductase inhibitor, eradicated the formation of the reductive metabolites M6, M9, and M11 in all species. Metabolites M14 and M15 were tested for cancer cell growth inhibition and induction of apoptosis and both showed substantial activity, with M14 displaying greater potency than 6S.

CONCLUSION

We conclude that 6S is metabolized extensively in mammalian species mouse, rat, dog, monkey, and human, and that there are significant interspecies differences to consider when planning preclinical trials toward 6S chemoprevention.

AKRs expression in peripheral blood lymphocytes from smokers: the role of body mass index

Aldo-keto reductases (AKRs) metabolize a wide range of substrates, including polycyclic aromatic hydrocarbons (PAHs), generating metabolites (o-quinones) and reactive oxygen species (ROS), which are capable of initiating and promoting carcinogenesis. Exposure to PAHs, their metabolites, and ROS further increase AKRs isoform expression that may amplify oxidative damage. Human AKR enzymes are highly polymorphic, and allelic variants may contribute to different AKRs expression in individuals. Despite the importance of AKRs in PAHs metabolism, there are no studies that evaluate, in general human populations, the effect of PAHs on AKRs expression in peripheral blood lymphocytes (PBLs). The aim of this study was to determine the effect of tobacco smoke exposure, and AKR1A1*2 and AKR1C3*2 polymorphisms, on AKR1A1 and AKR1C1-AKR1C3 messenger RNA (mRNA) levels in PBLs from smokers. In the smoker group, there is a statistically significant positive association between AKR1A1, AKR1C1, and AKR1C3 mRNA induction and urine cotinine levels in individuals with a body mass index (BMI) less than 25. However, AKR1A1*2 and AKR1C3*2 alleles did not influence AKR1A1 and AKR1C1-AKR1C3 mRNA levels. These results suggest that AKRs induction by PAHs in smokers' PBLs is associated with BMI; therefore, the role of adipose tissue accumulation in PAHs' effects needs further investigation.

Expression, purification, crystallization and preliminary X-ray diffraction analysis of carbonyl reductase from Candida parapsilosis ATCC 7330

The NAD(P)H-dependent carbonyl reductase from Candida parapsilosis ATCC 7330 catalyses the asymmetric reduction of ethyl 4-phenyl-2-oxobutanoate to ethyl (R)-4-phenyl-2-hydroxybutanoate, a precursor of angiotensin-converting enzyme inhibitors such as Cilazapril and Benazepril. The carbonyl reductase was expressed in Escherichia coli and purified by GST-affinity and size-exclusion chromatography. Crystals were obtained by the hanging-drop vapour-diffusion method and diffracted to 1.86 Å resolution. The asymmetric unit contained two molecules of carbonyl reductase, with a solvent content of 48%. The structure was solved by molecular replacement using cinnamyl alcohol dehydrogenase from Saccharomyces cerevisiae as a search model.

Alternative splicing in the aldo-keto reductase superfamily: implications for protein nomenclature

The aldo-keto reductase superfamily contains 173 proteins which are present in all phyla. Examination of the human and mouse genomes has identified that in some instances a single AKR gene can give rise to alternatively spliced mRNA variants which in some cases can give rise to more than one protein isoform. This is currently well documented in the AKR6A subfamily which contains the β-subunits of the voltage-gated potassium ion channels. With the emergence of second generation sequencing it is likely that the occurrence of transcript variants and protein isoforms from a single AKR gene may become common place. To deal with this issue we recommend that the Ensembl data-base nomenclature be used to annotate the transcript variants from a single AKR gene. However, since multiple transcript variants could give rise to either the same or multiple protein isoforms from the same AKR gene we also propose to expand the nomenclature of the AKR protein superfamily, so that when a protein isoform is shown to be expressed and is functional it would be assigned the standard AKR name followed by a "period or full-stop" and a number for that unique isoform. Numbers will be assigned chronologically and linked to the respective transcripts annotated in Ensembl e.g. AKR6A5.1 (Kvβ2.1) (AKR6A5-001, -006 and -201), followed by AKR6A5.2 (Kvβ2.2) (AKR6A5-002,-202). This nomenclature is expandable and it enables multiple protein isoforms to be assigned to their respective transcripts when they arise from the same AKR gene or for a single protein isoform to be assigned to multiple transcripts when the transcripts encode the same AKR protein.

[Activity of endogenous aldehydes catabolism enzymes in subcellular fractions of liver, heart and brain of rats at pubertal age under stress]

Activities of enzymes involved in redox transformation of endogenous aldehydes have been investigated in subcellular fractions of liver, heart, and brain of pubertal rats exposed to prolonged immobilization stress. In the liver aldo-keto reductase (AKR) activity in the postmitochondrial fraction and aldehyde dehydrogenase (ALDH) acivity of the mitochondrial fraction demonstrated a more pronounced decrease in 2-month-old rats. Rat heart postmitochondrial AKR and ALDH demonstrated opposite changes in their enzymatic activities, while activity of mitochondrial ALDH remained unchanged. Brain cells create conditions that favor effective utilization of endogenous aldehydes in metabolic redox pathways.