Engineering Phage Nanocarriers Integrated with Bio-Intelligent Plasmids for Personalized and Tunable Enzyme Delivery to Enhance Chemodynamic Therapy

Customizable and number-tunable enzyme delivery nanocarriers will be useful in tumor therapy. Herein, a phage vehicle, T4-Lox-DNA-Fe (TLDF), which adeptly modulates enzyme numbers using phage display technology to remodel the tumor microenvironment (TME) is presented. Regarding the demand for lactic acid in tumors, each phage is engineered to display 720 lactate oxidase (Lox), contributing to the depletion of lactic acid to restructure the tumor's energy metabolism. The phage vehicle incorporated dextran iron (Fe) with Fenton reaction capabilities. H2O2 is generated through the Lox catalytic reaction, amplifying the H2O2 supply for dextran iron-based chemodynamic therapy (CDT). Drawing inspiration from the erythropoietin (EPO) biosynthetic process, an EPO enhancer is constructed to impart the EPO-Keap1 plasmid (DNA) with tumor hypoxia-activated functionality, disrupting the redox homeostasis of the TME. Lox consumes local oxygen, and positive feedback between the Lox and the plasmid promotes the expression of kelch ECH Associated Protein 1 (Keap1). Consequently, the downregulation of the antioxidant transcription factor Nrf2, in synergy with CDT, amplifies the oxidative killing effect, leading to tumor suppression of up to 78%. This study seamlessly integrates adaptable T4 phage vehicles with bio-intelligent plasmids, presenting a promising approach for tumor therapy.

Metformin alleviates long-term high-fructose diet-induced skeletal muscle insulin resistance in rats by regulating purine nucleotide cycle

Nutrient excess caused by excessive fructose intake can lead to insulin resistance and dyslipidemia, which further causes the development of metabolic syndrome. Metformin is a well-known AMPK activator widely used for the treatment of metabolic syndrome, while the mechanism of AMPK activation remains unclear. The present study aimed to investigate the pharmacological effects of metformin on fructose-induced insulin resistance rat, and the potential mechanism underlying AMPK activation in skeletal muscle tissue. Results indicated that metformin significantly ameliorated features of insulin resistance, including body weight, Lee's index, hyperinsulinemia, dyslipidemia, insulin intolerance and pancreatic damage. Moreover, treatment with metformin attenuated the inflammatory response in serum and enhanced the antioxidant capacity in skeletal muscle tissue. The therapeutic effects of metformin on fructose-induced insulin resistance may be related to the activation of AMPK to regulate Nrf2 pathway and mitochondrial abnormality. Additionally, metformin suppressed the expression of adenosine monophosphate deaminase 1 (AMPD1) and up-regulated the expression of adenylosuccinate synthetase (ADSS) in the purine nucleotide cycle (PNC), which facilitated the increase of AMP level and the ratio of AMP/ATP. Therefore, we proposed a novel mechanism that metformin activated AMPK via increasing AMP by regulating the expression of AMPD1 and ADSS in PNC pathway.

The respiratory cytotoxicity of typical organophosphorus flame retardants on five different respiratory tract cells: Which are the most sensitive one?

Triphenyl phosphate (TPHP) is a frequently used flame retardant and indoor semi-volatile pollutant exposing humans with endocrinal disrupting effects. However, its respiratory tract toxicity remains unclear. Herein, we mainly focused on exploring the cytotoxicity of TPHP to the cells from five different parts of the human respiratory tract (from top to bottom): human nasal epithelial (HNEpC) cells, human bronchial epithelial (16HBE) cells, normal nasopharyngeal epithelial (NP69) cells, human lung epithelial cells (Beas-2B) cells, and human lung fibrocells (HFL1 cells) cells. The cell viability, micronucleus induction, endoplasmic reticulum stress gene, intracellular Ca²⁺ concentration, mitochondrial membrane potential (MMP) were investigated in short-term as well as extended exposure of TPHP. HFL1 and HNEpC cells were found to be irreversible damage, while other three type cells achieved homeostasis through self-rescue. Moreover, expression of downstream genes of Nrf2 signaling pathway were upregulated for 1.3-7.0 times and glutathione detoxification enzyme activity changed for 2-10 (U/mg protein) in HNEpC cells. Furthermore, the vascular endothelial growth factor (VEGF), a disease-related factor, increased 1.0-3.5-fold in HNEpC cells. RNA-sequencing results suggested that protein linkage recombination, molecular function regulation and metabolic processes signal pathway were all affected by TPHP exposure in HNEpC. This is a first report to compare respiratory cytotoxicity in whole human respiratory tract under OPFR exposure and found HNEpC cells were the most sensitive target of TPHP. Molecular biological mechanisms uncovered that TPHP exposure in HNEpC can induce the activation of MAPK signal pathway and demonstrate potential respiratory growth differentiation and stress disorder in human nasal cells upon TPHP exposure.

8-Oxypalmatine, a novel oxidative metabolite of palmatine, exhibits superior anti-colitis effect via regulating Nrf2 and NLRP3 inflammasome

Palmatine (PAL) is an isoquinoline alkaloid derived from Fibraureae caulis Pierre that has been used to relieve inflammatory diseases like ulcerative colitis (UC). The metabolites of PAL were believed to contribute significantly to its outstanding biological activities. 8-Oxypalmatine (OPAL), a liver-mediated oxidative metabolite of PAL, has been firstly identified in the present work. We aimed to comparatively investigate the potential effect and mechanism of OPAL and PAL on dextran sodium sulfate (DSS)-induced colitis in Balb/c mice. Results indicated that OPAL and PAL effectively mitigated clinical manifestations, DAI scores and pathological damage compared with the model group. Moreover, treatment with OPAL and PAL effectively mitigated oxidative stress markers and inflammatory mediators in colon. Additionally, OPAL and PAL significantly activated the Nrf2 pathway, while substantially suppressed the activation of NLRP3 inflammasome. Furthermore, OPAL showed superior anti-colitis effect to PAL, which was similar to the positive drug mesalazine with much smaller dosage. These findings suggested that OPAL exerted appreciable protective effect on DSS-induced colitis, at least in part, via activating Nrf2 pathway and inhibiting NLRP3 inflammasome. OPAL might have the potential to be further developed into a promising candidate for the treatment of UC.

Antioxidant and Anti-Inflammatory Properties of Rubber Seed Oil in Lipopolysaccharide-Induced RAW 267.4 Macrophages

Rubber seed oil (RSO) is a typical PUFA-enriched plant oil, but it has not been widely used as a healthy edible oil resource due to the lack of understanding of its nutritional values, health biological effects, and action mechanisms. This work was conducted to characterize the basic physicochemical properties, evaluate the antioxidant and anti-inflammatory properties, and explore the involved mechanisms of RSO in LPS-induced RAW 264.7 cells. In the present study, the basic physicochemical parameters of RSO indicated that RSO has good qualities as a potential edible plant oil resource. In LPS-induced macrophages, RSO supplementation displayed a significant antioxidant effect by decreasing ROS and MDA levels as well as elevating T-AOC. In addition, RSO supplementation showed an anti-inflammatory effect by reducing the production of NO, IL-1β, IL-6, and TNF-α while promoting the production of IL-10. Moreover, RSO supplementation decreased the mRNA expression of IL-6, IL-1β, TNF-α, iNOS, and MCP-1 genes while increasing the mRNA expression of the IL-10 gene. Furthermore, RSO supplementation increased Nrf2 protein expression and up-regulated antioxidant genes (HO-1 and NQO-1), which was accompanied by the decrease in TLR4 protein expression and NF-κB p65 phosphorylation as well as IκBα phosphorylation. This study provided some insight into the applications of RSO as a healthy edible oil resource.

Synthesis and biological evaluation of 1,2,4-oxadiazole core derivatives as potential neuroprotectants against acute ischemic stroke

Here, we report the synthesis and neuroprotective capacity of 27 compounds with a bisphenol hydroxyl-substituted 1,2,4-triazole core or 1,2,4-oxadiazole core for stroke therapy. In vitro studies of the neuroprotective effects of compounds 1-27 on sodium nitroprusside (SNP)-induced apoptosis in PC12 cells indicate that compound 24 is the most effective compound conferring potent protection against oxidative injury. Compound 24 inhibits reactive oxygen species (ROS） accumulation and restores the mitochondrial membrane potential (MMP). Moreover, further analysis of the mechanism showed that compound 24 activates the antioxidant defence system by promoting the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and increasing the expression of haem oxygenase 1 (HO-1). An in vivo study was performed in a rat model of transient focal cerebral ischaemia generated by the intraluminal occlusion of the middle cerebral artery (MCAO). Compound 24 significantly reduced brain infarction and improved neurological function. Overall, compound 24 potentially represents a promising compound for the treatment of stroke.

Tolerable upper intake level of iron damages the liver of weaned piglets

Iron is one of the essential trace elements, which is often supplemented as an additive to meet the growing needs of toddlers and young animals. Recommended nutrient intake (RNI) and tolerable upper intake levels (UL) are always set when the iron is supplemented. The purpose of this study was to evaluate the subacute (28 days) toxicity of UL iron to weaned piglet liver. Thirty 23-day-old weaned piglets were divided into three groups and, respectively, supplemented with 100, 300 or 3000 (UL) mg/kg iron. UL iron caused significant weight loss in 4th week (p < 0.05). Divalent metal transporter 1(DMT1) decreased significantly, ferroportin 1 and ferritin increased significantly in the liver of UL iron group (p < 0.05). Although there was no significant effect on liver morphology, UL iron significantly increased hepatic iron, reactive oxygen species (ROS), malondialdehyde (MDA) and protein carbonyl (p < 0.05). UL iron significantly reduced glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT) and total anti-oxidation capacity (T-AOC) in the liver (p < 0.05). Nuclear factor erythroid 2-related factor 2 (Nrf2) activated subunits of glutamate cysteine ligase (Gclc) and glutathione S-transferase A1 (Gsta1) upregulation in the UL iron group liver, thereby increasing resistance to oxidative stress. In conclusion, UL iron supplementation altered iron metabolism, generated free radicals, reduced antioxidant enzyme activity and activated Nrf2 signalling pathway in the weaned piglet liver.

Over-expression of Toll-like receptor 2 up-regulates heme oxygenase-1 expression and decreases oxidative injury in dairy goats

Background

Mastitis, an infection caused by Gram-positive bacteria, produces udder inflammation and oxidative injury in milk-producing mammals. Toll-like receptor 2 (TLR2) is important for host recognition of invading Gram-positive microbes. Over-expression of TLR2 in transgenic dairy goats is a useful model for studying various aspects of infection with Gram-positive bacteria, in vivo.

Methods

We over-expressed TLR2 in transgenic dairy goats. Pam3CSK4, a component of Gram-positive bacteria, triggered the TLR2 signal pathway by stimulating the monocytes-macrophages from the TLR2-positive transgenic goats, and induced over-expression of activator protein-1 (AP-1), phosphatidylinositol 3-kinase (PI3K) and transcription factor nuclear factor kappa B (NF-κB) and inflammation factors downstream of the signal pathway.

Results

Compared with wild-type controls, measurements of various oxidative stress-related molecules showed that TLR2, when over-expressed in transgenic goat monocytes-macrophages, resulted in weak lipid damage, high level expression of anti-oxidative stress proteins, and significantly increased mRNA levels of transcription factor NF-E2-related factor-2 (Nrf2) and the downstream gene, heme oxygenase-1 (HO-1). When Pam3CSK4 was used to stimulate ear tissue in vivo the HO-1 protein of the transgenic goats had a relatively high expression level.

Conclusions

The results indicate that the oxidative injury in goats over-expressing TLR2 was reduced following Pam3CSK4 stimulation. The underlying mechanism for this reduction was increased expression of the anti-oxidation gene HO-1 by activation of the Nrf2 signal pathway.

Effect of Nrf2 on rat ovarian tissues against atrazine-induced anti-oxidative response

The environmental persistence and bioaccumulation of herbicide atrazine may pose a significant threat to human health. In this experiment, Wistar rats were treated by 5, 25 and 125 mg·kg(-1) atrazine respectively for 28 days, and the oxidative stress responses as well as the activations of Nrf2 signaling pathway in ovarian tissues induced by atrazine were observed. The results showed that after be treated by atrazine, the proportion of atretic follicles in the rat ovary were increased, the contents of NO and MDA in the tissue homogenates were increased, the over-expressed Nrf2 transferred into the nuclei and played an antioxidant role by up-regulated the expression of II phase detoxifying enzymes such as HO1 and NQO1 and the expression of antioxidant enzymes such as CAT, SOD and GSH-PX.