Radiotherapy-sensitized cancer immunotherapy via cGAS-STING immune pathway by activatable nanocascade reaction.

Radiotherapy-induced immune activation holds great promise for optimizing cancer treatment efficacy. Here, we describe a clinically used radiosensitizer hafnium oxide (HfO2) that was core coated with a MnO2 shell followed by a glucose oxidase (GOx) doping nanoplatform (HfO2@MnO2@GOx, HMG) to trigger ferroptosis adjuvant effects by glutathione depletion and reactive oxygen species production. This ferroptosis cascade potentiation further sensitized radiotherapy by enhancing DNA damage in 4T1 breast cancer tumor cells. The combination of HMG nanoparticles and radiotherapy effectively activated the damaged DNA and Mn2+-mediated cGAS-STING immune pathway in vitro and in vivo. This process had significant inhibitory effects on cancer progression and initiating an anticancer systemic immune response to prevent distant tumor recurrence and achieve long-lasting tumor suppression of both primary and distant tumors. Furthermore, the as-prepared HMG nanoparticles "turned on" spectral computed tomography (CT)/magnetic resonance dual-modality imaging signals, and demonstrated favorable contrast enhancement capabilities activated by under the GSH tumor microenvironment. This result highlighted the potential of nanoparticles as a theranostic nanoplatform for achieving molecular imaging guided tumor radiotherapy sensitization induced by synergistic immunotherapy.

Dietary Supplement of Anoectochilus roxburghii (Wall.) Lindl. Polysaccharides Ameliorates Cognitive Dysfunction Induced by High Fat Diet via "Gut-Brain" Axis.

Purpose: Anoectochilus roxburghii (Wall.) Lindl. polysaccharides (ARPs) have been reported to exhibit multiple pharmacological activities including anti-inflammatory and anti-hyperglycemia. This study aims to investigate the effect of ARPs on cognitive dysfunction induced by high fat diet (HFD). Methods: Six-week-old male mice were treated with ARPs by dietary supplementation for 14 weeks. The effect of ARPs on cognitive function was determined by assessing the changes in spatial learning and memory ability, neurotrophic factors in hippocampus, inflammatory parameters, intestinal barrier integrity, and gut microbiota. Results: ARPs supplementation can effectively ameliorate cognitive dysfunction, decrease the phosphorylation levels of Tau protein in hippocampus. Meanwhile, the increased body weight, plasma glucose, total cholesterol, inflammatory factors induced by HFD were abolished by ARPs treatment. Furthermore, ARPs treatment restored the intestinal epithelial barrier as evidenced by upregulation of intestinal tight junction proteins. Additionally, ARPs supplementation significantly decreased the relative abundance of several bacteria genus such as Parabacteroides, which may play regulatory roles in cognitive function. Conclusion: These results suggest that ARPs might be a promising strategy for the treatment of cognitive dysfunction induced by HFD. Mechanistically, alleviation of cognitive dysfunction by ARPs might be associated with the "gut-brain" axis.

Therapeutic effect and mechanism of polysaccharides from Anoectochilus Roxburghii (Wall.) Lindl. in diet-induced obesity.

BACKGROUND: Recent studies have shown that polysaccharides from Anoectochilus roxburghii (Wall.) Lindl. (ARPs) can reduce blood glucose levels, ameliorate oxidative stress and inflammation. However, whether ARPs have a beneficial effect on diet-induced obesity remain to be determined. PURPOSE: This study aims to investigate the effect and mechanism of ARPs in improving obesity and metabolic disorders induced by high-fat diet (HFD). METHODS: In this study, 6-week-old male mice were fed with HFD or chow diet for 13 weeks, and a dietary supplementation with ARPs was carried out. Glucose tolerance test and insulin tolerance test were performed to measure the glucose tolerance and insulin sensitivity. Adipose tissue and liver were isolated for analysis by qRT-PCR, Western blotting, hematoxylin-eosin staining and immunostaining. RESULTS: At week 13, body weight and fat mass were significantly increased by HFD, but ARPs supplementation abolished these phenotypes. Compared with HFD group, thermogenic genes including Ucp-1, Pgc-1α, Prdm16 and Dio2 in adipose tissue were up-regulated in ARPs-treated mice. In addition, ARPs decreased liver lipid accumulation by reducing lipid synthesis and increasing oxidation. Meanwhile, dyslipidemia and insulin resistance induced by HFD were improved by ARPs. Mechanistically, ARPs can promote fat thermogenesis via AMPK/SIRT1/PGC-1α signaling pathway. CONCLUSION: Dietary supplementation of ARPs can protect mice against diet-induced obesity, fatty liver and insulin resistance. Our study reveals a potential therapeutic effect for ARPs in regulating energy homeostasis.

Effect of ascorbic acid on tyrosinase and its anti-browning activity in fresh-cut Fuji apple.

Tyrosinase (polyphenol oxidase) is the key enzyme of enzymatic browning in fruits and vegetables. In this research, the impact of ascorbic acid on tyrosinase and its anti-browning effect on fresh-cut Fuji apple were investigated. Ascorbic acid had a dual effect on tyrosinase with a half inhibitory concentration (IC50 ) of 13.40 ± 0.05 µM. Fluorescence assay demonstrated that ascorbic acid interacted with tyrosinase in a dynamic contaction caused by Förster's resonance energy transfer (FRET) and induced a conformational change of the enzyme. Thermodynamic analysis, copper interaction, and molecular docking further confirmed that ascorbic acid could chelate the copper ions located in active center and interact with amino acid residues of tyrosinase via hydrophobic interaction. In addition, ascorbic acid prevented the browning of fresh-cut apples by increasing APX activity and inhibiting PPO and POD activities which reduce the oxidation of total phenolics and flavonoids. PRACTICAL APPLICATIONS: The present study demonstrated that ascorbic acid had a strong inhibitory activity against tyrosinase (IC50 = 13.40 ± 0.05 µM) and anti-browning activity against fresh-cut Fuji apple. It could delay the browning degree of apple juice, increase APX activity, inhibit PPO and POD activities, and reduce the oxidation of total phenolics and flavonoids. These findings provided a basis for the feasible application of ascorbic acid on the preservation of fruits.

A sensitive aptasensor based on rolling circle amplification and G-rich ssDNA/terbium (III) luminescence enhancement for ofloxacin detection in food.

As the light-harvesting "antenna", G-rich oligonucleotides (such as the G-quadruplex) can interact with lanthanide (III) to bring a luminescent enhancement response. In this study, phenomenon of luminescent enhancement of G-triplex/terbium (III) (G3/Tb3+) and interaction between G3 and Tb3+ were first reported and characterized. Based on G3/Tb3+ luminescence, a label-free aptasensor for the detection of ofloxacin (OFL) residues in the food was developed. The OFL triggered the action of rolling circle amplification (RCA) allowed for the amplification product of G3-forming sequences in the single-stranded DNA, which promoted the conformational transition of the G3/Tb3+ complexes once the addition of Tb3+. Under the optimal conditions, the logarithmic correlation between the G3/Tb3+ luminescence intensity and the concentration of OFL was found to be linear in the range of 5-1000 pmol L-1 (R2 = 0.9949). The limit of detection was 0.18 pmol L-1 (3σ/slope). Additionally, the good recoveries of 90.19-108.89 % and the relative standard deviations values of 0.59-5.87 % were obtained in the application of the aptasensor detecting OFL in the practical samples. These results confirmed that the present aptasensor has a good analytical performance and bright prospect for detecting ofloxacin residues in food.

5-Methoxy-2-mercaptobenzimidazole as an efficient inhibitor on tyrosinase: Inhibitory activity and mechanism.

In this study, 5-methoxy-2-mercaptobenzimidazole (5-M-2-MB) was confirmed as an efficient tyrosinase inhibitor by methods of enzyme kinetic, fluorescence quenching, ANS-binding, thermodynamics, energy transfer, and molecular docking in combination. The results proved that 5-M-2-MB significantly inhibited the tyrosinase (IC50 = 60 ± 2 nM) in a reversible and competitive way with the Ki value of 80 ± 1 nM. It quenched the intrinsic fluorescence of tyrosinase through a static mechanism, and caused conformational change of the enzyme by increasing the hydrophobic region. Moreover, this compound could bind to tyrosinase and form 5-M-2-MB-tyrosinase complex by hydrogen bond and hydrophobic interaction. The interactions were generated between 5-M-2-MB and specific amino acid residues (Trp-358, Thr-308, Glu-356, and Asp-357) located on the A chain of tyrosinase. Therefore, this study would offer a theoretical foundation for developing the new tyrosinase inhibitor.

Discrimination of Zanthoxylum bungeanum Maxim through volatile aroma compounds analysis with artificial neural network.

Zanthoxylum bungeanum Maxim (ZBM), a special spice from Chinese different areas, have a widespread variation in quality and price. To avoid the commercial adulteration of ZBM, it is necessary to discriminate them from different areas. As volatile aroma compounds (VAC) have the potential to discriminate ZBM, electronic nose (E-nose) was used to preliminarily discriminate the VAC through sensor response analysis, radar chart analysis, and principal component analysis. Then, Gas chromatography-mass spectrometry (GC-MS) was utilized to identify VAC through hierarchical cluster analysis and quantitative analysis. Finally, artificial neural network (ANN) was employed to assess the accuracy of the discrimination of ZBM. As a result, we found that ZBM could be successfully discriminated between Chinese Sichuan and the other areas. Our findings would provide guidance for evaluating and predicting the variation of VAC of ZBM from different areas in further study. PRACTICAL APPLICATIONS: Zanthoxylum bungeanum Maxim (ZBM) is a traditional and important spice used in Sichuan cuisine especially hotpot, which are famous all over overseas. However, the ZBM from different producing areas bring various flavors, hampering the quality of Sichuan cuisine developing toward to standardization. Therefore, the authors in this work pursuit an effective way to distinguish the ZBM produced in Sichuan rather than in other province. According to the results of the present study, ZBM could be successfully discriminated between Chinese Sichuan and the other producing areas by using E-nose and GC-MS through artificial neural network. These findings would provide the guidance for evaluating the producing areas of ZBM to be whether or not Sichuan, which could offer the practical help in the purchase of the raw material in the supply chain. Besides, these also can be applied to predict the variation of volatile aroma compounds of the ZBM in the further study.

Inhibitory potential of 4-hexylresorcinol against α-glucosidase and non-enzymatic glycation: Activity and mechanism.

Inhibition of α-glucosidase as well as non-enzymatic glycation is thought as an effective method for treating type-2 diabetes mellitus. In this study, we investigated the inhibitory potential and mechanism of 4-hexylresorcinol against α-glucosidase and non-enzymatic glycation by using multispectroscopic analyses and molecular docking. The results of enzyme kinetics showed that 4-hexylresorcinol reversibly inhibited α-glucosidase activity in a noncompetitive way. Fluorescence quenching then revealed that it increased the hydrophobicity of α-glucosidase and changed the conformation of the enzyme by forming the α-glucosidase-hexylresorcinol complex. Thermodynamic analysis and molecular docking further demonstrated that the inhibition of 4-hexylresorcinol on the α-glucosidase was mainly dependent on hydrogen bond and hydrophobic interaction. Moreover, the 4-hexylresorcinol moderately inhibited the formation of fructosamine, and strongly suppressed the generation of α-dicarbonyl compounds and advanced glycation end products (AGEs). The interaction between 4-hexylresorcinol and bovine serum albumin was mainly driven by hydrophobic interaction. This study showed a novel inhibitor of α-glucosidase as well as non-enzymatic glycation, and provided a drug candidate for the prevention and treatment of type-2 diabetes.

Antityrosinase mechanism of ellagic acid in vitro and its effect on mouse melanoma cells.

The activities of ellagic acid in inhibiting mushroom tyrosinase and cell proliferation were evaluated in this research. The results of enzyme kinetics indicated that ellagic acid could effectively inhibit tyrosinase activity. The value of the semi-inhibitory rate (IC50 ) was 0.2 ± 0.05 mM. Ellagic acid inhibited tyrosinase activity in a reversible manner and was a mixed tyrosinase inhibitor. Furthermore, ellagic acid had a good inhibitory effect on the proliferation of mouse melanoma B16 cells and could induce apoptosis. The results acquired from fluorescence spectroscopy revealed that the interaction of ellagic acid with tyrosinase depended on hydrogen bond and electrostatic force. In addition, computational docking showed that ellagic acid interacted with amino acid residues of tyrosinase (Asn19 and Lys372) by hydrogen bond and produced electrostatic interaction with amino residue Lys18. PRACTICAL APPLICATIONS: In the present research, the antityrosinase mechanism of ellagic acid and its effect on mouse melanoma cells were investigated. This study suggested that ellagic acid had a strong inhibitory activity against tyrosinase and cell proliferation,which laid an experimental foundation for the development of new drugs and whitening products. The combined multispectral methods used in this research can be applied to the screening of other antityrosinase inhibitors, further promoting the development and utilization of tyrosinase inhibitors.

Inhibition of α-glucosidase activity and non-enzymatic glycation by tannic acid: Inhibitory activity and molecular mechanism.

The inhibition of α-glucosidase and glycation is considered as an effective approach for the treatment of type 2 diabetes. In this study, multispectroscopic and molecular docking techniques were employed to investigate the inhibition of tannic acid on α-glucosidase and glycation. Kinetics analyses revealed that tannic acid had a significant inhibition on α-glucosidase (IC50 = 0.35 ±â€¯0.02 µM) in a reversible and mixed competitive manner. The results acquired from fluorescence quenching and ANS-binding fluorescence methods revealed that tannic acid could bind to α-glucosidase and reduce the hydrophobic area on the surface of the enzyme. In addition, synchronous fluorescence analysis showed that tannic acid decreased the hydrophobicity of α-glucosidase and changed the conformation of the enzyme. In vitro glycation assays showed that tannic acid had strong inhibitory effects on the formation of fructosamine, dicarbonyl compounds, and fluorescent AGEs. ANS-binding fluorescence analysis showed that tannic acid could bind to BSA and reduce the hydrophobicity of BSA in glycation. Moreover, the results of molecular docking showed the interaction between tannic acid and α-glucosidase was mainly driven by hydrogen bond, electrostatic, and hydrophobic interaction. And the interaction between tannic acid and BSA was mainly driven by hydrogen bond and hydrophobic interaction.

Efficacy and Safety of Brinzolamide as Add-On to Prostaglandin Analogues or ß-Blocker for Glaucoma and Ocular Hypertension: A Systematic Review and Meta-Analysis.

Background: Brinzolamide as a carbonic anhydrase inhibitor could be combined with other intraocular pressure (IOP) lowering drugs for glaucoma and ocular hypertension (OHT), but the efficacy was controversial. So, this study was used to assess the efficacy and safety of brinzolamide as add-on to prostaglandin analogues (PGAs) or ß-blocker in treating patients with glaucoma or OHT who fail to adequately control IOP. Methods: We searched PubMed, Embase, MEDLINE, Cochrane Library, and clinicaltrials.gov from inception to October 4, 2018. Randomized controlled trials of brinzolamide as add-on to PGAs or ß-blocker for glaucoma and OHT were included. Meta-analysis was conducted by RevMan 5.3 software. Results: A total of 26 trials including 5,583 patients were analyzed. Brinzolamide produced absolute reductions of IOP as an adjunctive therapy for patients with glaucoma or OHT. Brinzolamide and timolol were not significantly different in lowering IOP as add-on to PGAs (9 am: P = 0.07; 12 am: P = 0.66; 4 pm: P = 0.66). Likewise, brinzolamide was as effective as dorzolamide in depressing IOP (9 am: P = 0.59; 12 am: P = 0.94; 4 pm: P = 0.95). For the mean diurnal IOP at the end of treatment duration, there were no statistical differences in above comparisons (P > 0.05). Compared with brimonidine (b.i.d.), there was a significant reduction of IOP in brinzolamide (b.i.d.) at 9 am (P < 0.0001); however, the difference was cloudy in thrice daily subgroup (P = 0.44); at 12 am, brinzolamide (b.i.d.) was similar to brimonidine (b.i.d.) in IOP-lowering effect (P = 0.23), whereas brimonidine (t.i.d.) led to a greater effect than brinzolamide (t.i.d.) (P = 0.02). At 4 pm, brinzolamide (b.i.d.) was superior IOP-lowering effect compared with brimonidine (b.i.d.) (P = 0.0003); conversely, the effect in brinzolamide (t.i.d.) was lower than brimonidine (t.i.d.) (P < 0.0001). For the mean diurnal IOP, brinzolamide was lower in twice daily subgroup (P < 0.00001); brimonidine was lower in thrice daily subgroup (P < 0.00001). With regard to the safety, brinzolamide and dorzolamide had a higher incidence of taste abnormality; moreover, brinzolamide resulted in more frequent blurred vision; dorzolamide resulted in more frequent ocular discomfort and eye pain. Timolol resulted in more frequent blurred vision and less conjunctival hyperemia. Brimonidine resulted in more frequent ocular hyperemia. As to other adverse events (AEs) (conjunctivitis, eye pruritus, foreign body sensation in eyes, and treatment-related AEs), brinzolamide was similar to other three active comparators. Conclusions: Brinzolamide, as add-on to PGAs or ß-blocker, significantly decreased IOP of patients with refractory glaucoma or OHT and the AEs were tolerable.

Anti-melanogenesis properties of condensed tannins from Vigna angularis seeds with potent antioxidant and DNA damage protection activities.

Condensed tannins contained in food are known to have many beneficial impacts on human health. In this study, we attempt to evaluate the structural features, antityrosinase effects, anti-melanogenesis properties, antioxidant activity and DNA damage protection activity of condensed tannins purified from the seeds of Vigna angularis (Willd.) Ohwi et Ohashi. MALDI-TOF MS, ESI-Full-MS, and HPLC-ESI-MS demonstrated that condensed tannins are composed of procyanidins, prodelphinidins and their gallates, among which procyanidins are the dominant components. As reversible and mixed-type inhibitors of tyrosinase, condensed tannins from V. angularis strongly inhibited the monophenolase and odiphenolase activities with IC50 values of 130.0 ± 0.5 and 35.1 ± 2.0 µg mL-1, respectively. What's more, condensed tannins had a good inhibitory effect on cell proliferation, cellular tyrosinase activity, and melanogenesis of B16 mouse melanoma cells. Based on fluorescence quenching analyses, these compounds were determined to be effective quenchers of the enzyme and its substrates. According to molecular docking, the strong interaction between condensed tannins and tyrosinase was mainly driven by hydrogen bonding and hydrophobic force. In addition, condensed tannins showed a powerful antioxidant capacity and DNA damage protection activity. Therefore, condensed tannins from V. angularis have feasible applications in food, medicine, and the cosmetics industry.

Down-regulation of C-type natriuretic peptide receptor by vasonatrin peptide in cardiac myocytes and fibroblasts.

AIM: To investigate the regulatory effects of vasonatrin peptide (VNP) on the expression of C-type natriuretic peptide receptor (NPR-C) in cultured neonatal rat cardiac myocytes and fibroblasts. METHODS: Quantitative RT-PCR was undertaken to evaluate the levels of NPR-C mRNA and radioimmunoassay was used to determine the formation of intracellular cGMP. RESULTS: Twenty-four hours hypoxic exposure increased the level of NPR-C mRNA in cardiomyocytes, while did not alter the expression of NPR-C in cardiac fibroblasts. VNP (10(-8)-10(-6) mol/L) reduced the levels of NPR-C mRNA in cardiac myocytes induced by hypoxia in a concentration-dependent manner, and with high concentration (10(-6) mol/L) also decreased the expression of NPR-C in cardiac fibroblasts and air-control cardiac myocytes. The inhibitory effects of VNP on the expression of NPR-C was mimicked by 8-bromo-cGMP 10(-6) mol/L (a membrane permeable analog of cGMP). VNP (10(-8)-10(-6) mol/L) increased the formation of intracellular guanosine-3',5'-cyclic monophosphate (cGMP) in both cardiac myocytes and fibroblasts. HS-142-1, the particulate guanylyl cyclase-coupled receptor antagonist, partially abrogated the above effects of VNP. CONCLUSION: Hypoxic exposure for 24 h up-regulated the expression of NPR-C in cultured neonatal rat cardiac myocytes. VNP decreased the expression of NPR-C in cardiac myocytes and fibroblasts under both air-control and hypoxic condition, which was at least partially mediated by guanylate cyclase linked natriuretic peptide receptors through increasing the intracellular cGMP.

[Inhibition of moderate hypoxia-induced protein synthesis by vasonatrin peptide in cultured neonatal rat cardiomyocytes].

The present work was to investigate the effects of vasonatrin peptide (VNP) on cardiomyocyte protein synthesis induced by moderate hypoxia. In cultured neonatal rat cardiomyocytes, MTT methods, total protein measurement and (3)H-leucine incorporation were used to calculate the cell number and measure the protein synthesis of cardiomyocytes. Furthermore, radioimmunoassay was undertaken to observe the effects of VNP on the intracellular levels of cAMP, cGMP and the concentration of endothelin (ET) in the culture medium. The results showed that both the cell number and protein synthesis decreased with severe hypoxia for 24 h. In contrast, under moderate hypoxia, cardiomyocyte hypertrophy developed; the protein synthesis as evidenced by total protein content and 3H-eucine incorporation increased significantly. VNP reduced cardiomyocyte protein synthesis induced by moderate hypoxia in a dose-dependent manner. Furthermore, VNP increased the intracellular level of cGMP and decreased the concentration of ET in the culture medium under moderate hypoxia, but had no effect on the level of cAMP. These results suggest that VNP inhibits moderate hypoxia-induced protein synthesis in cultured neonatal rat cardiac myocytes. This effect is mediated, at least in part, by an increase in intracellular cGMP, a reduction in synthesis, and/or a release in ET of cardiomyocytes.