Realgar bioleaching solution suppress ras excessive activation by increasing ROS in Caenorhabditis elegans

Flavonoids from Lycium barbarum Leaves Exhibit Anti-Aging Effects through the Redox-Modulation

Lycium barbarum leaves are a kind of vegetable, and modern nutrition studies have found that they have an anti-aging function. Our study aims to investigate the anti-aging effects of Lycium barbarum leaf flavonoid (LBLF) extracts and its underlying molecular mechanism. LBLFs were purified using D101 and polyamide resin, characterized by ultraperformance liquid chromatography coupled with mass spectrometry, and administered to hydrogen peroxide (H₂O₂)-treated human umbilical vein endothelial cells (HUVECs) and Caenorhabditis elegans. Appropriate enrichment conditions were optimized through dynamic adsorption and desorption experiments, the content of flavonoids reached 909.84 mg/g, rutin and kaempferol being the main ones. LBLFs attenuated H₂O₂-induced HUVEC apoptosis, decreased reactive oxygen species and malondialdehyde production levels, increased superoxide dismutase, glutathione peroxidase and catalase activities. Furthermore, pre-treatment with LBLF increased mRNA expression of erythropoietin (EPO) and heme oxygenase-1 (HO-1) via the mitogen-activated protein kinase (MAPK) signaling pathway in HUVECs. Compared with 100 µM rutin monomer, LBLF prolonged the lifespan of Caenorhabditis elegans, enhanced their mobility in middle life stages and upregulated expression of sod-2, gcs-1 and skn-1 genes, which indicated that the anti-aging effects of LBLF were due to its redox-modulation.

Ultrasonic-assisted extraction of polysaccharides from Auricularia auricula and effects of its acid hydrolysate on the biological function of Caenorhabditis elegans

The present study was designed to explore the in vivo-antioxidant capacity and the probable mechanism of AAPs-H, prepared from Auricularia auricula polysaccharides with the optimal extraction conditions by Box-Behnken design and acid hydrolysis, using Caenorhabditis elegans as a model organism. The effects of AAPs-H on the locomotion behavior, life span, antioxidant-related enzymes activities, and antioxidants levels in C. elegans were studied. Furthermore, the potentials of AAPs-H in up-regulating the expression of antioxidant-related genes in C. elegans, such as skn-1, sod-3 and sir-2.1, were also discussed. AAPs-H demonstrated a highly significant protective effect against the damage caused by paraquat, could significantly increase U-Turn frequency of worms (p < 0.01), extend their lifespan, enhance antioxidant systems including GR by 63.96% (p < 0.05), GSH-Px by 71.16% (p < 0.01), SOD by 78.65% (p < 0.01) and CAT by 98.52% (p < 0.01), increase the level of GSH by 28.12% (p < 0.05), and decrease the level of MDA by 39.29% (p < 0.01). The qRT-PCR results showed that AAPs-H could up regulate mRNA expression levels of skn-1, sod-1, sod-2, sod-3 and sir-2.1 in wild-type C. elegans (>1.6 fold) when treated with the concentration of 0.4 mg/mL (p < 0.05 or p < 0.01). Our studies provide evidence that AAPs-H improves antioxidant defense system, and up-regulation of oxidative stress related genes for prevention of stress damage in C. elegans.

Amyloid-beta (Aβ1-42)-induced paralysis in Caenorhabditis elegans is reduced through NHR-49/PPARalpha

Alzheimer´s disease is a neurodegenerative disorder characterized by the misfolding and aggregation of amyloid β (Aβ). Agonists of peroxisomal proliferator-activated receptors (PPARs) are discussed as anti-amyloidogenic compounds, e.g. due to their cholesterol-lowering activities. In a previous study we have shown in Caenorhabditis elegans expressing human Aβ in muscle cells, that inhibition of steroid-signaling, by RNAi of respective members of the signaling pathway or by reducing cellular cholesterol uptake, both increases the nuclear translocation of the foxo transcription factor DAF-16 and concomitantly reduces Aβ-induced paralysis. Using RNAi in the present study we show that NHR-49/PPARalpha inhibits steroidal-signaling upstream of DAF-9, a cytochrome P₄₅₀-dependent enzyme which generates dafachronic acids as ligands for the nuclear hormone receptor DAF-12, and upstream of DAF-12 itself. The NHR-49/PPARalpha agonist fenofibrate reduces Aβ-induced paralysis in dependence on nhr-49 and nuclear translocation of DAF-16. In conclusion, activation of NHR-49/PPARalpha inhibits the steroidal-signaling pathway which increases the nuclear translocation of DAF-16 and inhibits the Aβ-induced phenotype in an Alzheimer model of C. elegans.

Amyloid-beta induced paralysis is reduced by cholecalciferol through inhibition of the steroid-signaling pathway in an Alzheimer model of Caenorhabditis elegans

Objectives: Alzheimer's disease (AD) is a neurodegenerative disorder resulting from the accumulation of toxic β-amyloid (Aβ) aggregates in the human brain. Epidemiological studies have shown that elevated cholesterol plasma levels are associated with the development of AD and we have previously shown that cholesterol restriction reduces the Aβ-induced paralysis in an Alzheimer model of the nematode Caenorhabditis elegans. In the present study we investigated the effects of the cholesterol homolog cholecalciferol, i.e. vitamin D, on Aβ-induced paralysis in C. elegans and its interference with the steroid-signaling pathway. Methods: Aβ-induced paralysis was assessed in the C. elegans strain CL2006, expressing human Aβ_1-42 under control of a muscle-specific promoter. Knockdown of members of the steroid-signaling pathway was achieved by RNA interference (RNAi). Nuclear translocation of foxo transcription factor DAF-16 was visualized using the strain TJ356, carrying a daf-16::gfp transgene. Results: Cholecalciferol at a concentration of 1 µM reduced the Aβ-induced paralysis in CL2006 significantly, which was reverted by increasing the cholesterol concentration in the medium. Knockdown of nhr-8, daf-36, daf-9 or daf-12, all reduced Aβ-induced paralysis to the same extent as cholecalciferol with no additional or synergistic effects under co-application. Functional DAF-16 proved to be crucial for the effects of cholecalciferol and DAF-16 nuclear translocation was increased by cholecalciferol and also RNAi versus nhr-8, daf-36, daf-9 or daf-12 with no additive or synergistic effects. Conclusions: Our results suggest, that cholecalciferol inhibits Aβ-induced paralysis in C. elegans through inhibition of steroid-signaling and the concomitant nuclear translocation of DAF-16.

Evaluation of the antioxidant effects of acid hydrolysates from Auricularia auricular polysaccharides using a Caenorhabditis elegans model

Caenorhabditis elegans is an important model organism for studying stress response mechanisms. In this paper, C. elegans was used to evaluate the antioxidant effects of acid hydrolysates from Auricularia auricular polysaccharides.

Kushui Rose (R. Setate x R. Rugosa) decoction exerts antitumor effects in C. elegans by downregulating Ras/MAPK pathway and resisting oxidative stress

Kushui rose (R. Setate x R. Rugosa) (KR) is a traditional Chinese medicine proven to be a potent antioxidant, and used for thousands of years. Approximately 30% of all human cancers relevant to mutational activated Ras, and over-activated Ras are accompanied by increased accumulation of reactive oxygen species (ROS). Thus, one way of developing anticancer drugs is to reduce ROS accumulation. Therefore, KR was predicted to have potential to combat over-activated Ras-related cancer. C. elegans with let‑60(gf)/ras mutant, which exhibited tumor-like symptoms of the multivulva phenotype, was employed to determine the effect of KR on Ras/MAPK pathway. Other strains of worms and H2DCF-DA dye were also applied to study the antioxidant stress capacity of KR. This study was aimed to determine whether KR has a potential effect on combat over-activated Ras-related cancer through resistance to oxidative stress. Our results showed that Kushui rose decoction (KRD) has potent antioxidant activity in vitro, and can inhibit over-activated Ras in vivo. Further, KRD significantly suppressed over-activated Ras/MAPK pathway by regulating oxidative stress-related proteins, such as forkhead transcription factor (DAF-16), glutathione S-transferase-4 (GST-4), superoxide dismutases (SODs) and heat shock protein-16.2 (HSP-16.2). However, essential oil and hydrosol of KR had no effect on over-activated Ras. Thus these results reminded us that people usually soak rose in hot water to prepare 'rose tea' as an effective way for health care. Thus, KRD was demonstrated to be a potential drug candidate for combating over-activated Ras-related cancer as an antioxidant.

Properties of realgar bioleaching using an extremely acidophilic bacterium and its antitumor mechanism as an anticancer agent

Realgar is a naturally occurring arsenic sulfide (or Xionghuang, in Chinese). It contains over 90% tetra-arsenic tetra-sulfide (As4S4). Currently, realgar has been confirmed the antitumor activities, both in vitro and in vivo, of realgar extracted using Acidithiobacillus ferrooxidans (A. ferrooxidans). Bioleaching, a new technology to greatly improve the use rate of arsenic extraction from realgar using bacteria, is a novel methodology that addressed a limitation of the traditional method for realgar preparation. The present systematic review reports on the research progress in realgar bioleaching and its antitumor mechanism as an anticancer agent. A total of 93 research articles that report on the biological activity of extracts from realgar using bacteria and its preparation were presented in this review. The realgar bioleaching solution (RBS) works by inducing apoptosis when it is used to treat tumor cells in vitro and in vivo. When it is used to treat animal model organisms in vivo, such as mice and Caenorhabditis elegans, tumor tissues grew more slowly, with mass necrosis. Meanwhile, the agent also showed obvious inhibition of tumor cell growth. Bioleaching technology greatly improves the utilization of realgar and is a novel methodology to improve the traditional method.

Shengmai Formula suppressed over-activated Ras/MAPK pathway in C. elegans by opening mitochondrial permeability transition pore via regulating cyclophilin D

Since about 30% of all human cancers contain mutationally activated Ras, down regulating the over-activation of Ras/MAPK pathway represents a viable approach for treating cancers. Over-activation of Ras/MAPK pathway is accompanied by accumulation of reactive oxygen species (ROS). One approach for developing anti-cancer drugs is to target ROS production and their accumulation. To test this idea, we have employed C. elegans of let-60 (gf) mutant, which contain over-activated let-60 (the homolog of mammalian ras) and exhibit tumor-like symptom of multivulva phenotype, to determine whether anti-oxidants can affect their tumor-like phenotype. Specifically we studied the effect of Shengmai formula (SM), a traditional Chinese medicine that has strong anti-oxidant activity, on the physiology of let-60 (gf) mutants. Unexpectedly, we found that SM treatment led to the opening of mitochondrial permeability transition pore by regulating cyclophilin D and then triggered oxidative stress and related signaling pathway activation, including p53, JNK, and p38/MAPK pathways. Finally, SM induced mitochondrial pathway of apoptosis and inhibited the tumor-like symptom of the multivulva phenotype of let-60(gf) mutants. Our results provide evidences to support that SM act as a pro-oxidant agent and could serve as a potential drug candidate for combating over-activated Ras-related cancer.

Realgar nanoparticle-based microcapsules: preparation and in-vitro/in-vivo characterizations

Objectives

The aim of this study was to prepare microcapsules for the oral delivery of realgar nanoparticles (RN) that are also capable of improving its stability.

Methods

RN and RN-based microcapsules (RNM) were prepared using ball milling and solvent evaporation techniques, respectively. Properties such as particle size, ζ-potential (ZP), morphology and X-ray diffractometer (XRD) were investigated. In addition, drug release, bioavailability and antitumour studies were also performed.

Key findings

The nanoparticles appeared round or elliptical in shape with a mean size of 85.4 ± 3.5 nm and a ZP of −34.3 ± 1.7 mV. The obtained RNM appeared spherical and not aggregated with a relatively narrow size distribution. XRD analysis revealed that ball milling technique did not change the crystallinity of the realgar powder. RN and RNM exhibited considerable higher release of As2S2, bioavailability and antitumour efficacies compared with crude realgar. Furthermore, RNM could protect RN directly exposed to the air and light, and therefore increased the stability of the RN.

Conclusions

The developed RNM demonstrated a greater potential as a delivery system for realgar.