Inhibition Of Enzyme Activity Research Articles

ANTIOXIDANT ACTIVITY AND INHIBITORY EFFECT OF 2,4,4'-TRIHYDROXYCHALCONE ON DIGESTIVE ENZYMES RELATED TO OBESITY

The aim of this study was to investigate the antioxidant activity and inhibitory effect of 2,4,4'-trihydroxychalcone on digestive enzymes related to obesity, including sucrase, α-amylase, and lipase. The in vitro antioxidant activities of three concentrations of 2,4,4'-trihydroxychalcone (100, 300, and 500 µg/ml) were determined using 2,2-diphenyl-1-picrylhydrazyl radical scavenging, reducing power, and ferrous ion chelating assays. Moreover, in vitro inhibition of lipase, α-amylase, and sucrase enzyme activities by 2,4,4'-trihydroxychalcone was determined using a specific assay for each enzyme. 2,4,4'-Trihydroxychalcone has been shown to have antioxidant properties and inhibits sucrase, α-amylase and lipase activities. These findings suggest that 2,4,4′-trihydroxychalcone demonstrated an antioxidant activity and can effectively inhibit the key enzymes related to obesity.

In vitro contraceptive activities, molecular docking, molecular dynamics, MM-PBSA, non-covalent interaction and DFT studies of bioactive compounds from Aegle marmelos. Linn., leaves.

Introduction: Bioactive molecules from natural sources having contraceptive properties were excellent alternatives for modern hormonal contraceptives. Researchers around the world were working on identifying contraceptive leads targeting the male reproductive system rather than the usual female contraceptives. The lack of proper understanding on male contraceptive protein drug targets leads to insufficient evidence on activities of identified contraceptive compounds. The proteins specific to the male reproductive system and involved in sperm-egg fusion will be an excellent drug target to identify the male non-hormonal, reversible contraceptive leads. Inhibiting sperm hyaluronidase activity by natural non-hormonal compounds will lead to reversible and non-hormonal male contraception. The Aegle marmelos Linn. is one such important medicinal plant with valuable phytocompounds, used traditionally as a potential contraceptive measure. The in vivo experiments on leaf extracts of Aegle marmelos. Linn containing terpenes, sterols, and alkaloids shows prominent contraceptive activities. Moreover, this study explores the potential ability of the leaf extract on inhibiting the sperm hyaluronidase action with additional molecular details on the interaction between sperm hyaluronidases and three phytocompounds such as aegeline, marmin, and marminol. Material and methods: The in vitro hyaluronidase inhibition assay and Computer Assisted Sperm Analysis (CASA) were used to evaluate the male contraceptive properties of the Aegle marmelos Linn. leaf extract. To identify the interaction profile of aegeline, marmin, and marmenol on sperm cell hyaluronidases the in-silico methods such as molecular docking, Non-Covalent Interaction analysis, Molecular dynamics, and Molecular Mechanics Poisson Boltzmann Surface Area were used. Results and discussion: The results of in vitro hyaluronidase inhibition assay and Computer Assisted Sperm Analysis shows the inhibition of hyaluronidase enzymatic activity and reduced sperm activities in the presence of leaf extracts. After incubation with leaf extracts for about 30 minutes time intervals show, the motility drops from progressive to non-progressive and ended up with complete immotile in 100 μg/ml concentration of leaf extract. The results of molecular docking, Non-Covalent Interaction analysis, Molecular dynamics, and Molecular mechanics Poisson Boltzmann Surface Area show that the phytocompounds marmin, and aegeline have the potential ability to inhibit sperm hyaluronidase.

An indispensable role of TAZ in anoikis resistance promoted by OTUB1 deubiquitinating enzyme in basal-like triple-negative breast cancer cells

Aggressive cancers, such as triple-negative breast cancer (TNBC), are mostly fatal because of their potential to metastasize to distant organs. Cancer cells acquire various abilities to metastasize, including resistance to anoikis, an apoptotic cell death induced by loss of anchorage to the extracellular matrix. Transcriptional coactivator with PDZ binding motif (TAZ) and Yes-associated protein (YAP), the downstream effectors of the Hippo pathway, regulate cell- and tissue-level architectures by responding to mechanical microenvironments of cells, including the cell–extracellular matrix interaction. The Hippo pathway is frequently disrupted in cancer cells, and TAZ and YAP are irrelevantly activated, potentially resulting in anchorage-independent survival/proliferation of cancer cells and metastatic progression. The study aims to investigate the roles of TAZ and YAP in anoikis resistance in basal-like (BL) TNBC cells, which comprise a major subtype (>70%) of TNBC. We found that TAZ and YAP had nonredundant roles in anchorage-independent cancer cell survival or anoikis resistance. Particularly, TAZ was indispensable for anoikis resistance in BL-TNBC cells but not for survival of non-transformed mammary epithelial cells (MECs). In contrast, YAP, a paralog of TAZ, was indispensable for survival of both non-transformed MECs and cancer cells. Therefore, TAZ might be a preferable therapeutic target against dissemination of aggressive cancer cells without killing normal cells. Interestingly, TAZ was abnormally stabilized in BL-TNBC cells under non-adherent conditions, which promoted anoikis resistance. Furthermore, OTUB1, a deubiquitinating enzyme, was responsible for the stabilization of TAZ in detached BL-TNBC cells. Importantly, simultaneous high expression of TAZ and OTUB1 was associated with poor prognosis in BC. Thus, OTUB1 has emerged as a potentially druggable target. Successful inhibition of OTUB1 enzymatic activity is expected to downregulate TAZ and eventually prevents metastasis of aggressive cancers, such as BL-TNBC.

Calcium-bound structure of bovine cytochrome c oxidase

The crystal structure of bovine cytochrome c oxidase (CcO) shows a sodium ion (Na+) bound to the surface of subunit I. Changes in the absorption spectrum of heme a caused by calcium ions (Ca2+) are detected as small red shifts, and inhibition of enzymatic activity under low turnover conditions is observed by addition of Ca2+ in a competitive manner with Na+. In this study, we determined the crystal structure of Ca2+-bound bovine CcO in the oxidized and reduced states at 1.7 Å resolution. Although Ca2+ and Na+ bound to the same site of oxidized and reduced CcO, they led to different coordination geometries. Replacement of Na+ with Ca2+ caused a small structural change in the loop segments near the heme a propionate and formyl groups, resulting in spectral changes in heme a. Redox-coupled structural changes observed in the Ca2+-bound form were the same as those previously observed in the Na+-bound form, suggesting that binding of Ca2+ does not severely affect enzymatic function, which depends on these structural changes. The relation between the Ca2+ binding and the inhibitory effect during slow turnover, as well as the possible role of bound Ca2+ are discussed.

Antifungal and Nanozyme Activities of Metal–Organic Framework‐derived CuO@C

Postharvest fungal infection is the common cause of fresh fruit losses. Thus, effective antifungal agents are highly required. Herein, copper‐based metal–organic frameworks (MOFs) were used as a precursor for the synthesis of copper oxide (CuO) embedded into carbon (CuO@C). The materials' crystallinity was confirmed using X‐ray diffraction. X‐ray photoelectron spectroscopy (XPS) and atomic absorption spectroscopy (AAS) approve the elemental species and concentration of copper in the synthesized materials. Transmission electron microscopy (TEM), high‐resolution TEM (HR‐TEM), and scanning electron microscopy (SEM) reveal the successful formation of CuO‐embedded C, that is, CuO@C, with a particle size of 36–123 nm. CuO@C nanoparticles are used as an antifungal agent against four economic postharvest plant pathogens; Alternaria alternata (black spot disease of tomato), Fusarium oxysporum (rot disease of tomato), Penicillium digitatum (gray mold disease of lemon), and Rhizopus oryzae (soft rot disease of banana). The inhibition zones were 36 ± 0.5, 20.2 ± 0.4, 16 ± 0.5, and 10.2 ± 0.1 mm for R. oryzae, P. digitatum, F. oxysporum, and A. alternata, respectively. CuO@C antifungal action includes significant inhibition of cellulases and amylase enzyme activity, decreasing the potentiality of fungal pathogenicity and fruit disease. CuO@C exhibited high antifungal activity against postharvest antifungal species.

Bioassay-Guided Isolation and Identification of Antibacterial Components against Escherichia coli from Industrial Hemp Leaves

Industrial hemp leaves have raised much interest in nutraceuticals and functional foods areas. To expand its application ranges, the antibacterial activities of industrial hemp leaf extract on Escherichia coli, Staphylococcus aureus, and Bacillus cereus were evaluated and the active components were screened. As a result, the industrial hemp leaf extract was found to have strong bacteriostatic effects on E. coli and S. aureus. Bioassay-guided fractionation and isolation from fractions active against E. coli were conducted. Two compounds, cannabidivarinic acid and cannabidiolic acid, were firstly recognized by analytical HPLC by comparing the retention times and UV spectra with standards and later isolated using preparative HPLC. Moreover, the antibacterial mechanisms of cannabidivarinic acid and cannabidiolic acid were investigated by testing the alkaline phosphatase activity, β-galactosidase activity, conductivity, proteins leakage, nucleic acid leakage, and scanning electron microscope observation. The results demonstrated that cannabidivarinic acid and cannabidiolic acid could destroy the cell wall and membrane of E. coli, resulting in the inhibition of enzyme activity and leakage of contents. They could damage the bacteria cell envelope as well. Presented results pointed out cannabidivarinic acid and cannabidiolic acid as promising natural bacteriostatic agents for the food, pharmaceutical, and cosmetic industry.

Study on the mechanism of Phellinus igniarius total flavonoids in reducing uric acid and protecting uric acid renal injury in vitro

BackgroundUric acid nephropathy (UN) is a complication of hyperuricemia (HUA), which has a great impact on people's lives. Here, we evaluated the therapeutic potential of total flavonoids of Phellinus igniarius (TFPI) in vivo and studied the anti UN effect of TFPI in vitro. MethodsHyperuricemia was induced by intraperitoneal injection of potassium oxonate in ICR mice. After intervention with TFPI, we evaluated the levels of serum uric acid (UA) and creatinine (CR), and the contents of xanthine oxidase (XOD) and adenosine deaminase (ADA) in liver. To explore the effect and molecular mechanism of TFPI on UN, we treated HK-2 cells with monosodium urate (MSU) to study the effect of TFPI on apoptosis and inflammation. In addition, to explore the mechanism of TFPI on uric acid transport we evaluated the relationship between uric acid transporter ABCG2 and inflammatory signaling pathway TLR4-NLRP3. ResultsIn the model mice, TFPI significantly decreased the levels of UA and Cr, which may be related to the inhibition of XOD enzyme activity. In HK-2 cells, the response of TFPI to MSU can effectively inhibit apoptosis and activation of TLR4-NLRP3 signaling pathway and promote the expression of ABCG2. ConclusionsTFPI can significantly inhibit the release of inflammatory factors and promote the expression of ABCG2 by targeting TLR4 receptor and NLRP3 inflammasome. And targeted inhibition of XOD enzyme activity to reduce uric acid level and inhibit the development of UN.

Inhibitory effects of ultrasonic and rosmarinic acid on lipid oxidation and lipoxygenase in large yellow croaker during cold storage.

Lipid oxidation will lead to the deterioration of flavor, color and texture of aquatic products with high fatty acid content. The mechanism of ultrasound (US) combined with rosmarinic acid (RA) on lipid oxidation and endogenous enzyme activities of large yellow croaker during cold-storage (4 ℃) was investigated. The result showed that the US and RA have synergistic effects in delaying lipid oxidation and inhibiting endogenous lipase and lipoxygenase (LOX) activities related to oxidation. The inhibition of LOX activity by RA was dose-dependent, and US showed a negative effect on the inhibition of enzyme activity in the presence of low concentration RA. Moreover, RA changes the enzyme structure through static fluorescence quenching and interaction with enzyme molecules. Hydrogen bonding and hydrophobic interaction are the main interaction forces between RA and LOX. This study could provide basic mechanism of US treatment cooperating with polyphenols to inhibit lipid oxidation during food preservation.

Steady-state kinetic analysis of reversible enzyme inhibitors: A case study on calf intestine alkaline phosphatase.

Enzymes are important drug targets and inhibition of enzymatic activity is an important therapeutic strategy. Enzyme assays measuring catalytic activity are utilized in both the discovery and development of new drugs. Colorimetric assays based on the release of 4-nitrophenol from substrates are commonly used. 4-Nitrophenol is only partly ionized to 4-nitrophenolate under typical assay conditions (pH 7-9) leading to under-estimation of product formation rates due to the much lower extinction coefficient of 4-nitrophenol compared to 4-nitrophenolate. Determination of 4-nitrophenol pKa values based on absorbance at 405nm as a function of experimental pH values is reported, allowing for calculation of a corrected extinction coefficient at the assay pH. Characterization of inhibitor properties using steady-state enzyme kinetics is demonstrated using calf intestine alkaline phosphatase and 4-nitrophenyl phosphate as substrate at pH ∼8.2. The following kinetic parameters were determined: Km=40±3µM; Vmax=72.8±1.2µmolmin-1mg protein-1; kcat=9.70±0.16s-1; kcat/Km=2.44±0.16 × 105 M-1s-1 (mean±SEM, N=4). Sodium orthovanadate and EDTA were used as model inhibitors and the following pIC50 values were measured using dose-response curves: 6.61±0.08 and 3.07±0.03 (mean±SEM, N=4). Rapid dilution experiments determined that inhibition was reversible for sodium orthovanadate and irreversible for EDTA. A Ki value for orthovanadate of 51±8nM (mean±SEM, N=3) was determined. Finally, data analysis and statistical design of experiments are discussed.

Changes in Enzyme Activity in Post-Pyrogenic Soils (Physical Model Experiment)

Presented data on changes in the enzymatic activity of soils under pyrogenic effects in model experiments simulating natural fires. A series of experiments aimed at studying pyrogenic inhibition of enzyme activity and dynamics of their recovery in post-pyrogenic soils were performed under laboratory and natural conditions. The objects of the study were sandy soil (Seropeski, Arenosol) and migratory-segregation black soil (Haplic Chernozem (Loamic, Pachic) Rostov region. Model experiments were carried out by treating soil samples with gas burner flame (amount of heat 87–435 × 103 J) and pyrogenic action of wood fuel combustion (10–279 × 106 J). In the first case, the exposure duration was 1 to 5 min, and in the second case from 1 to 120 min. The response of enzymes (catalase, invertase, urease, peroxidase and phosphatase) to low-temperature plasma exposure (1–120 min) was found to differ depending on the enzyme group and degree of exposure. It was found that the depth of penetration of thermal effects in simulated fires was limited to the top soil layer (0–10 cm), and the radius of spread relative to the combustion source did not exceed 20 cm. Temperature values varied according to time, source of exposure and amount of fuel (400–600°C). Sandy soils and chernozem were heated and cooled down at different rates. The activity of catalase, invertase and urease were found to be inversely related to the intensity of pyrogenic exposure. The dynamics of enzyme activity recovery in post-pyrogenic soils was traced. Invertase activity recovered faster than catalase and urease activity, but full recovery after a year does not occur. The results obtained indicate a significantly prolonged effect of inhibition of enzymatic activity during simulation of natural fires.

Innovation in agriculture and the agri-food chain: Some insights

<abstract> <p>Information on the impact of climate change on the growth of weed species and their sensitivity to herbicides could help to establish an efficient weed management strategy. Due to the excessive use of acetolactate synthase (ALS) inhibitor herbicides, resistance to those herbicides is increasing globally. It is thus crucial to find out whether the efficacy of these herbicides will change in the future due to the increase in carbon dioxide concentration and in the temperatures. This work therefore aims to evaluate the impact of temperature and carbon dioxide (CO<sub>2</sub>) changes on the growth of <italic>Amaranthus retroflexus</italic>, <italic>Bromus tectorum</italic>, <italic>Chenopodium album</italic> and <italic>Echinochloa crus-galli</italic>, including the assessment of herbicide (sulfosulfuron 75% + metsulfuron methyl 5%) (SMM) efficiency in these weeds. A factorial experiment was performed in a completely randomized design with three factors, including two CO<sub>2</sub> concentrations (400 and 700 ppm), two temperature regimes (30/20 ℃ and 34/24 ℃ day/night), and six herbicide rates (0, 25, 37.5, 50, 62.5 and 75 g a.e. ha<sup>−1</sup>) in four replications. As a result, it was seen that temperature and CO<sub>2</sub> concentration changes influenced the morphological parameters of the weeds. The main effect of the temperature regime on the herbicide's effectiveness, except for <italic>B. tectorum</italic>, was not statistically significant. The interaction of herbicide rates and temperature with the herbicide's efficacy was only significant for <italic>E. crus-galli</italic>; the highest efficacy was observed at 30/20 ℃ and at a rate 50% higher (75 g a.e. ha<sup>−1</sup>) than the recommended one (50 g a.e. ha<sup>−1</sup>). Increasing CO<sub>2</sub> concentrations enhanced the herbicide's efficiency and ALS enzyme activity inhibition in all the weed species, but had the greatest effect on C<sub>3</sub> weeds. Our results showed that temperature and CO<sub>2</sub> levels associated with climate change can interact to alter the efficacy of herbicidal weed control and that there are differences between plants with the C<sub>3</sub> and C<sub>4</sub> photosynthesis pathways. As a result, in the future, breeders and farmers could achieve the results desired by applying lower doses of this herbicide.</p> </abstract>

Effect of addition of certain substances during slurry preparation to optimize biogas production

Biogas from anaerobic digestion of organic substance has become the available replacement for the fossil fuel. This research was carried out to investigate the effect of certain substances added during slurry preparation to enhance biogas formation. The biodigester was locally fabricated using plastic container of 25liter capacity. The slurry was prepared by adding Calcium Sulphate, Chopped plantain leaf, and pretreated substrate. After 15 days of anaerobic fermentation, the slurry with CaSO4 gave more biogas of 0.403kg followed by the pretreated which gave 0.270kg. The one with plantain leaf gave the least biogas. This is as a result of inhibition of enzyme activity by certain chemical substance from the leaf. Also, the amount of Calcium sulphate to be added should not exceed 200g to 1kg of substrate to be used for slurry preparation.

Alpha-Mangostin Attenuates Oxidative Stress and Apoptosis in Scopolamine-Induced Amnesic Rat Brains

The extract from Garcinia mangostana L. pericarp was reported to scavenge radicals, inhibit acetylcholinesterase (AChE) activity, and improve spatial memory in scopolamine (SCOP)-induced amnesic rats. This study investigated α-mangostin (α-MG) neuroprotective effects against SCOP-induced neurotoxicity.The compound was evaluated for anti-AChE and antioxidant properties in vitro, and its preventive effect on apoptosis and oxidative stress in SCOP-treated rat brains. AChE inhibitory property of α-MG was assessed by fast blue B (FB) salt and β-naphthyl acetate (NA) and Ellman’s assays. The antioxidant properties of α-MG were assessed by ferric reducing antioxidant power (FRAP), scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH), and 2,2′-azino-bis-[3-ethylbenzothiazoline-6-sulfonic acid] (ABTS•+) radicals. Brain levels of malondialdehyde (MDA), lipid peroxidation marker, and activities of the caspase-3 enzyme, an apoptosis-related marker, were determined in SCOP-treated rats pretreated with donepezil (DPZ) and α-MG. IC50 of α-MG and DPZ for AChE activity were 64.23±0.22 and 32.46±0.14 mg/mL, respectively. α-MG and DPZ (100-600 µg/mL) gave FRAP values within the range of 20-410 µmol Fe2+/L. The IC50 of α-MG and DPZ for ABTS were 21.52±3.45 and 14.53±1.86 µg/mL, and for DPPH were 38.12±8.36 and 29.44±5.13 µg/mL, respectively. Prior given to SCOP-induced rats, DPZ and α-MG (50 and 100 mg/kg) reduced MDA levels, and pretreatment of DPZ and α-MG (50 mg/kg), but not α-MG (100 mg/kg), attenuated the increase of caspase-3 activity in cerebral cortex and hippocampus (P<0.05), but not in the basal forebrain. The present study is the first report of α-MG as a potential neuroprotective candidate, and its mechanism might be involved in ameliorating scopolamine-induced neurotoxicity via inhibition of lipid peroxidation and caspase-3 enzyme activity in the cerebral cortex and hippocampus.

Isolation of α-mangostin from mangosteen (Garcinia mangostana L.) peels and evaluation of its inhibitory activity toward α-glucosidase and α-amylase in the combination with acarbose

Using the natural agents with inhibitory activity against digestive enzymes α-glucosidase and α-amylase capable of hydrolyzing carbohydrates into glucose to reduce blood glucose levels in the blood is one of the effective strategies to control diabetes, especially type II diabetes. α-Mangostin (AMG) was proven to have strong biological activities, such as antifungal, antibacterial, anti-inflammatory, anti-cancer. However, the evaluation of the antidiabetic activity of this substance through inhibition of starch hydrolytic enzymes activity has not been fully carried out, especially when they are combined with commercial drugs, such as acarbose. In this study, AMG was isolated from the peels of the mangosteen grown in Vietnam using a simple isolation process with two steps: i) fractionation of the material in n-hexane solvent, and ii) chromatography of n-hexane fraction on a silica gel column combined with crystallization. The α-glucosidase inhibitory activity (AGI) and α-amylase inhibitory activity (AAI) of purified AMG alone or in combination with acarbose were then determined spectrophotometrically. The obtained results indicated that AMG had a purity of > 98% by HPLC examination and its chemical structure was confirmed by NMR spectra analysis combined with the reference. The isolated AMG showed good AGI and AAI with IC50 values of 8.25 µg/mL and 24.5 µg/mL, respectively. The AGI increased to 69.4% when AMG (5.0 µg/mL) was combined with acarbose at a concentration of 2.5 µg/mL, while the AAI did not have a clear synergistic effect. Our finding suggests the possibility of using the combination formula to enhance acarbose efficacy in treatment of the disease.

Effects of ammonia exposure on anxiety behavior, oxidative stress and inflammation in guppy (Poecilia reticulate)

Ammonia is one of the most important aquatic environmental factors, which is of great concern. In order to evaluate the effect of ammonia on guppy (Poecilia reticulate), fish were exposed to increased concentrations (0, 12.50, 25.00, 41.67, 62.50 mg/L) of ammonia for 48 h. After exposure, we measured the anxiety behavior, antioxidant enzymes and pro-inflammation genes (TNF-α, IL-1β and IL-6) of guppy. The results showed that ammonia stress induced fish anxiety, which was manifested by the increased latency to enter the upper half and decreased time spent in upper half compared with control fish. The guppy showed oxidative stress after 48 h of ammonia stress as evidenced by decreases in the activities of antioxidant enzymes and an increase in lipid hydroperoxide content. With prolonged ammonia stress, the expressions of HSP70, HSP90, TNF-α, IL-1β and IL-6 mRNA at first had an increasing trend, and then decreased, all of which were significantly higher than the control levels at 12 h and 24 h after ammonia stress (P < 0.05). Ammonia significantly upregulated these genes mRNA levels after 48 h exposure, suggesting that heat shock proteins and innate immune system may try to protect cells from oxidative stress induced by ammonia stress. Our study showed that higher ammonia exposure induced oxidative stress in exposed fish, since inhibition of antioxidant enzymes activity and increases in lipid peroxidation, and inflammation occurred. Furthermore, the results will be helpful to understand the mechanism of ammonia toxicity in guppys.

Metabolic enzyme LDHA activates Rac1 GTPase as a noncanonical mechanism to promote cancer.

The glycolytic enzyme lactate dehydrogenase A (LDHA) is frequently overexpressed in cancer, which promotes glycolysis and cancer. The oncogenic effect of LDHA has been attributed to its glycolytic enzyme activity. Here we report an unexpected noncanonical oncogenic mechanism of LDHA; LDHA activates small GTPase Rac1 to promote cancer independently of its glycolytic enzyme activity. Mechanistically, LDHA interacts with the active form of Rac1, Rac1-GTP, to inhibit Rac1-GTP interaction with its negative regulator, GTPase-activating proteins, leading to Rac1 activation in cancer cells and mouse tissues. In clinical breast cancer specimens, LDHA overexpression is associated with higher Rac1 activity. Rac1 inhibition suppresses the oncogenic effect of LDHA. Combination inhibition of LDHA enzyme activity and Rac1 activity by small-molecule inhibitors displays a synergistic inhibitory effect on breast cancers with LDHA overexpression. These results reveal a critical oncogenic mechanism of LDHA and suggest a promising therapeutic strategy for breast cancers with LDHA overexpression.

Targeting 7-dehydrocholesterol reductase against EV-A71 replication by upregulating interferon response

Recent studies have shown a close link between viral infections and cholesterol metabolism. Here, we reported that 7-dehydrocholesterol reductase (DHCR7), a terminal enzyme for catalyzing cholesterol synthesis in the Kandutsch-Russell pathway, is harnessed by enterovirus A71 (EV-A71) benefitting for its replication. Overexpression of DHCR7 resulted in upregulating of EV-A71 replication, while the S14A mutation, which reduces DHCR7 enzyme activity, has no effect on EV-A71 replication. Knockdown of DHCR7 expression with small interfering RNA (siRNA) or enzyme activity inhibition with pharmacological inhibitor AY9944 could significantly inhibit EV-A71 replication. Adding cholesterol to DHCR7 knockdown cells or AY9944-treated cells could rescue EV-A71 replication. More importantly, prophylactic administration of AY9944 effectively protected mice from lethal EV-A71 infection. In addition, the natural cholesterol precursor 7-dehydrocholesterol (7-DHC), which is converted to cholesterol by DHCR7, has a similar effect against EV-A71 infection. Mechanistically, AY9944 or 7-DHC treatment can specifically promote IRF3 phosphorylation to activate interferon response. Moreover, AY9944 effectively cleared coxsackievirus B3 (CVB3) and coxsackievirus A16 (CVA16) infections in vitro. In conclusion, pharmacological modulation of DHCR7 might provide a chance for treatment of enterovirus infection, including EV-A71.

ALDH1-Mediated Autophagy Sensitizes Glioblastoma Cells to Ferroptosis.

The fatal clinical course of human glioblastoma (GBM) despite aggressive adjuvant therapies is due to high rates of recurrent tumor growth driven by tumor cells with stem-cell characteristics (glioma stem cells, GSCs). The aldehyde dehydrogenase 1 (ALDH1) family of enzymes has been shown to be a biomarker for GSCs, and ALDH1 seems to be involved in the biological processes causing therapy resistance. Ferroptosis is a recently discovered cell death mechanism, that depends on iron overload and lipid peroxidation, and it could, therefore, be a potential therapeutic target in various cancer types. Since both ALDH1 and ferroptosis interact with lipid peroxidation (LPO), we aimed to investigate a possible connection between ALDH1 and ferroptosis. Here, we show that RSL3-induced LPO and ferroptotic cell death revealed RSL3-sensitive and -resistant malignant glioma cell lines. Most interestingly, RSL3 sensitivity correlates with ALDH1a3 expression; only high ALDH1a3-expressing cells seem to be sensitive to ferroptosis induction. In accordance, inhibition of ALDH1a3 enzymatic activity by chemical inhibition or genetic knockout protects tumor cells from RSL3-induced ferroptotic cell death. Both RSL-3-dependent binding of ALDH1a3 to LC3B and autophagic downregulation of ferritin could be completely blocked by ALDH inhibition. Therefore, ALDH1a3 seems to be involved in ferroptosis through the essential release of iron by ferritinophagy. Our results also indicate that ferroptosis induction might be a particularly interesting clinical approach for targeting the highly aggressive cell population of GSC.

Research Progress of Natural Active Substances with Uric-Acid-Reducing Activity.

Hyperuricemia is a metabolic disease caused by the accumulation of uric acid in the body. Allopurinol, benzbromarone, and febuxostat, which are available in the market, have reduced the circulating urate levels; however, they exhibit serious side effects. Therefore, it is reasonable to develop a new active antihyperuricemia drug with few side effects. With the deepening of research, numerous kinds of literature have shown that natural active substances are effective in the treatment of hyperuricemia with a variety of sources and few side effects, which have become the focus of research in recent years. This review focuses on natural active substances with uric-acid-reducing activity and discusses their pharmacological effects. More specifically, the bioactive compounds of natural active substances are divided into five categories: natural extracts, monomer compounds extracted from plants, natural protease hydrolysates, peptides, and probiotic bacteria. In addition, the mechanisms by which these bioactive compounds exhibit hypouricemic effects can be divided into four classes: inhibition of key enzyme activities, promotion of uric acid excretion and inhibition of reabsorption in the kidney, promotion of decomposing uric acid precursors, and promotion of decomposing uric acid. Overall, this current and comprehensive review examines the role of natural active substances in the treatment of hyperuricemia.

Baseline Sensitivity to and Succinate Dehydrogenase Activity and Molecular Docking of Fluxapyroxad and SYP-32497 in Rice Sheath Blight (Rhizoctonia solani AG1-IA) in China

Rice sheath blight caused by Rhizoctonia solani occurs worldwide and is mainly controlled by fungicides. SYP-32497 is a novel succinate dehydrogenase inhibitor, which interferes with the succinate ubiquinone reductase in the mitochondrial respiratory chain of fungi. This study aimed to evaluate the baseline sensitivity of R. solani from 13 major rice producing areas in China to SYP-32497 and fluxapyroxad. The study also explored the cause for the activity discrepancy between SYP-32497 and fluxapyroxad via an enzyme activity inhibition test and molecular docking. A total of 360 R. solani isolates were sensitive to SYP-32497 and fluxapyroxad. Baseline sensitivities were unimodally distributed with mean values of 0.00667 ± 0.00475 and 0.0657 ± 0.0250 μg mL−1, respectively, for SYP-32497 and fluxapyroxad. Enzyme activity assays and molecular docking results revealed that SYP-32497 exhibited a much higher SDH inhibition (IC50 = 0.300 μg mL−1) than to fluxapyroxad (IC50 = 1.266 μg mL−1) because of its excellent SDH binding ability via hydrogen bonding, π-cation, and hydrophobic interactions. These results suggest that SYP-32497 is a good suitable control agent for alternative rice sheath blight.