Regulation mechanism of oxidative stress induced by high glucose through PI3K/Akt/Nrf2 pathway in juvenile blunt snout bream (Megalobrama amblycephala)

Toxicological effects of polystyrene nanoplastics and perfluorooctanoic acid to Gambusia affinis

Plastic pollution has attracted huge attention from public and scientific community in recent years. In the environment, nanoplastics (NPs, <100 nm) can interact with persistent organic pollutants (POPs) such as perfluorooctanoic acid (PFOA) and may exacerbate associated toxic impacts. The present study aims to explore the single and combined ecotoxicological effects of PFOA and polystyrene nanoplastics (PS-NPs, 80 nm) on the PI3K/AKT3 signaling pathway using a freshwater fish model Gambusia affinis. Fish were exposed individually to PS-NPs (200 μg/L) and PFOA (50, 500, 5000 μg/L) and their chemical mixtures for 96 h. Our results showed that the co-exposure significantly altered the mRNA relative expression of PI3K, AKT3, IKKβ and IL-1β, compared to corresponding single exposure and control groups, indicating that the PFOA-NP co-exposure can activate the PI3K/AKT3 signaling pathway. The bioinformatic analyses showed that AKT3 had more probes and exhibited a significantly sensitive correlation with DNA methylation, compared to other genes (PIK3CA, IKBKB, and IL1B). Further, the mRNA expressions of PIK3CA, AKT3, and IKBKB had a significant correlation with copy number variation (CNV) in human liver hepatocellular carcinoma (LIHC). And PIK3CA had the highest mutation rate among other genes of interest for LIHC. Moreover, AKT3 showed a relatively lower expression in TAM and CAF cells, compared to PIK3CA, IKBKB, and IL1B. Besides, hsa-mir-155-5p was closely correlated with AKT3, PIK3CA, IKBKB, and IL1B. In summary, these results provide evidence that NPs could enhance the carcinogenic effects of POPs on aquatic organisms and highlight possible targets of LIHC induced by PFOA-NP co-exposure.

6'-O-Caffeoylarbutin from Que Zui tea ameliorates acetaminophen-induced liver injury via enhancing antioxidant ability and regulating the PI3K signaling pathway

Que Zui tea (QT), a traditional herbal tea in China, has a significant hepatoprotective effect. 6'-O-Caffeoylarbutin (CA) is the most abundant chemical compound in the QT. However, the hepatoprotective effect of CA has not been investigated. This study is aimed to evaluate the protective effect of CA on acetaminophen (APAP) induced hepatotoxicity in vivo and in vitro and its possible underlying mechanism. In APAP-induced HepG-2 cells, CA inhibited intracellular ROS accumulation and cell apoptosis, and improved the expression of antioxidants including SOD, CAT and GSH. In APAP-administrated mice, CA pretreatment remarkably ameliorated the histopathological damage and inflammatory response, and antioxidant enzyme activity in the serum and liver tissues. Moreover, the immunohistochemistry and immunofluorescence assay results revealed that the CA markedly reduced ROS production and apoptosis, and activated antioxidant transcription factor Nrf2 in the liver. Meanwhile, molecular docking results showed that the strong binding force of CA and PI3K was due to the higher number of hydrogen- and π-bonds with active site residues. Notably, CA pretreatment significantly regulated the expression of PI3K, Akt, Nrf2, NQO1, HO-1, Bcl-2, Bax, caspase-3, and caspase-9 proteins in APAP-treated liver tissues. These data demonstrated that CA had a protective effect against APAP-induced hepatotoxicity via regulating the PI3K/Akt and Nrf2 signaling pathway.

miR-335-laden B Cell-Derived Extracellular Vesicles Promote SOX4-Dependent Apoptosis in Human Multiple Myeloma Cells

Multiple myeloma (MM) is characterized by the accumulation of malignant plasma cells in the bone marrow. Despite novel therapies, MM still remains an incurable cancer and new strategies are needed. Increased expression of the transcription factor Sex-determining region Y-related high-mobility-group box transcription factor 4 (SOX4) has been correlated with tumor development and progression through a variety of distinct processes, including inhibition of apoptosis, increased cell invasion and metastasis, and induction and maintenance of cancer-initiating cells. The role of SOX4 in MM is largely unknown. Since SOX4 is a known target of miR-335, we used miR-335 to assess whether SOX4 modulation could promote apoptosis in MM cells. Using an MM cell model we show that miR-335 acts both on SOX4-related genes (AKT, PI3K) and hypoxia-inducible factor 1-alpha (Hif1-α). In addition, we show miR-335-laden extracellular vesicles induced in B cells (iEVs) are also effective in targeting SOX4, causing apoptosis. Collectively, we propose that miR-335-laden iEVs could be developed as a novel form of gene therapy in MM.

ABCC5 facilitates the acquired resistance of sorafenib through the inhibition of SLC7A11-induced ferroptosis in hepatocellular carcinoma

Sorafenib is a first-line molecular-target drug for advanced hepatocellular carcinoma (HCC), and reducing sorafenib resistance is an important issue to be resolved for the clinical treatment of HCC. In the current study, we identified that ABCC5 is a critical regulator and a promising therapeutic target of acquired sorafenib resistance in human hepatocellular carcinoma cells. The expression of ABCC5 was dramatically induced in sorafenib-resistant HCC cells and was remarkably associated with poor clinical prognoses. The down-regulation of ABCC5 expression could significantly reduce the resistance of sorafenib to HCC cells. Importantly, activation of PI3K/AKT/NRF2 axis was essential for sorafenib to induce ABCC5 expression. ABCC5 increased intracellular glutathione (GSH) and attenuated lipid peroxidation accumulation by stabilizing SLC7A11 protein, which inhibited ferroptosis. Additionally, the inhibition of ABCC5 enhanced the anti-cancer activity of sorafenib in vitro and in vivo. These findings demonstrate a novel molecular mechanism of acquired sorafenib resistance and also suggest that ABCC5 is a new regulator of ferroptosis in HCC cells.

Addition of Bamboo Charcoal to Selenium (Se)-Rich Feed Improves Growth and Antioxidant Capacity of Blunt Snout Bream (Megalobrama amblycephala)

Simple Summary

In our previous studies, we determined that juvenile blunt snout bream (Megalobrama amblycephala) require a selenium (Se) dietary intake of 0.958–0.959 mg/kg based on the quadratic fitting method. Nevertheless, growth rates were significantly affected, and the expression of anti-inflammatory factors was inhibited when the feed contained excessively high Se concentrations. Given its activity as an insoluble carrier, bamboo charcoal can be used as a dietary supplement in fish feed to absorb and slowly release excess nutrients. However, these hypotheses have not been evaluated in diets containing excess Se. The present study determined that 2–3 g/kg bamboo charcoal inclusion in Se-rich feed could improve the growth performance of blunt snout bream. Dietary bamboo charcoal supplementation mobilized the antioxidant system and inhibited the inflammatory response by activating Nrf2-Keap1 signaling while suppressing NF-κB signaling.

Abstract

The ability of bamboo charcoal to reduce the negative effects of high dietary selenium (Se) concentrations was assessed by feeding juvenile blunt snout bream (Megalobrama amblycephala) one of five Se-rich diets (1.5 mg/kg Se; 36% protein, 8.7% lipid) containing graded levels (0–4 g/kg) of bamboo charcoal powder for eight weeks. There were four tanks (350 L) of fish (initial weight 16.0 ± 0.5 g) for each treatment, and the fish were fed to satiation four times each day. At the end of the feeding trial, all of the fish from each tank were weighed to calculate the growth performance. Blood samples were firstly obtained to collect plasma for the biochemical indexes determination. Liver tissues were then collected to determine the antioxidant enzyme activities and gene expression. Dorsal muscles were also collected to determine the nutrient composition. The results show that when the bamboo charcoal content in the Se-rich feed ranged between 0 and 3 g/kg, the weight growth rate (WGR) and specific growth rate (SGR) values increased with the higher dietary bamboo charcoal content, and the maximum WGR and SGR values were achieved when the bamboo charcoal content in the Se-rich feed was 2–3 g/kg (p < 0.05). The Se content in muscle tissues decreased significantly with the increased bamboo charcoal content (p < 0.05) in the Se-rich feed, which ranged from 0 to 4 g/kg. When the bamboo charcoal content in the Se-rich feed was 2–3 g/kg, the levels of glucose (GLU) and albumin (ALB) in plasma reached a maximum (p < 0.05), whereas the level of alkaline phosphatase (ALP) reached a minimum (p < 0.05). Additionally, the activities of catalase (CAT), total superoxide dismutase (T-SOD), total antioxidative capacity (T-AOC), and glutathione peroxidase (GSH-Px) were significantly enhanced (p < 0.05) when the bamboo charcoal content was 3 g/kg. In contrast, the malondialdehyde (MDA) level increased sharply when the bamboo charcoal content in the Se-rich feed was 1 g/kg, compared to the control group and the groups supplemented with 2–3 g/kg bamboo charcoal (p < 0.05). Regarding mRNA-level gene expression, the results show that dietary supplementation with 0 to 3 g/kg of bamboo charcoal increased the expression of keap1 and nrf2, whereas nfkb expression was inhibited (p < 0.05). The mRNA expression of the antioxidant enzymes cat, gpx, and mn-sod was consistently enhanced in the group fed with the 3 g/kg bamboo charcoal diet (p < 0.05). The expression of the pro-inflammatory cytokines tnfα and tgfβ was inhibited in the groups supplemented with 2–3 g/kg bamboo charcoal, whereas the expression of anti-inflammatory cytokines (il10) increased in the bamboo charcoal supplementation groups compared to the control group (p < 0.05). Generally, supplementation with 2–3 g/kg of bamboo charcoal in Se-rich feed improved the growth performance, physiological status, and antioxidant enzyme activities of blunt snout bream. Moreover, bamboo charcoal supplementation in Se-rich diets stimulated the antioxidant system and inhibited the inflammatory response by activating Nrf2-Keap1 and suppressing NF-κB.

Acanthopanax senticosus Promotes Survival of Tilapia Infected With Streptococcus iniae by Regulating the PI3K/AKT and Fatty Acid Metabolism Signaling Pathway

Streptococcus has greatly restricted the development of healthy tilapia aquaculture. As a green and efficient feed addition, Acanthopanax senticosus (APS) has been increasingly used in culture, but it is unclear whether it represents a disease-resistant feed. Genetically improved farmed tilapia (GIFT, Oreochromis niloticus) was fed with a feed supplemented with 0 (control), 0.5, 1, 2, 4, and 8‰ APS for 56 days, after which fish were injected with 5.9 × 10⁶ CFU/ml Streptococcus iniae into the abdominal cavity. At 96 h after infection, the cumulative survival of GIFT in control and 0.5‰ APS treatments was significantly lower than in other treatments; at APS supplementation rates of 1 and 2‰, serum glucose, triglycerides, and cholesterol contents were all significantly lower than in control treatment fish. Hepatic glycogen and triglyceride contents of 1‰ APS treatment fish were significantly higher than those in fish in control treatment. Transcription levels of peroxisome proliferator activated receptor α (PPAR), fatty acid synthase (FAS), and lipoprotein Lipase (LPL) genes were upregulated, and their expression levels in fish in 1, 2, and 4‰ treatments were significantly higher than those in fish in control treatment at 96 h after S. iniae infection. After 96 h of infection, the red blood cells, hemoglobin, hematocrit, and white blood cells of fish in 1‰ APS treatment were significantly lower than those of fish in 4 and 8‰ treatments; hepatic catalase activity was activated at 48 h, superoxide dismutase activity was also significantly upregulated at 96 h, and the malondialdehyde content significantly decreased. It is noted that 0.5–2‰ APS treatments significantly activated the expression of PI3K and AKT in the liver, while inhibiting the expression of Caspase-9. Therefore, feed with 1‰ APS can promote hepatic glycogen and lipid metabolism in GIFT after infection with S. iniae, which is beneficial to alleviating oxidative stress damage and cell apoptosis in liver tissue.

Tributyrin Plays an Important Role in Regulating the Growth and Health Status of Juvenile Blunt Snout Bream (Megalobrama amblycephala), as Evidenced by Pathological Examination

The present study aimed to assess the role of tributyrin (TB) in regulating the growth and health status of juvenile blunt snout bream (Megalobrama amblycephala) through an 8-week feeding experiment. Six groups were fed experimental diets with added TB percentages of 0% (control group), 0.03%, 0.06%, 0.09%, 0.12% and 0.15%. The present results showed that TB supplementation in feed had some positive impacts on FW, WG, FCR and SGR, and the best results were found in the 0.06% TB group (P<0.05). However, TB supplementation in feed had no significant effects on SR, CF, VSI or whole-body composition (P>0.05). TB supplementation in feed increased antioxidant capacity and immunological capacity and attenuated the inflammatory response by increasing the activity of T-SOD, GPx, CAT and the levels of anti-inflammatory cytokines (IL-10 and TGF-β) and decreasing the levels of MDA and anti-inflammatory cytokines (TNF-α) (P<0.05). Furthermore, TB supplementation improved immunity by increasing the levels of immunoglobulins (IgM and IgG), C3 and IFN-γ (P<0.05). Surprisingly, 0.06%-0.12% TB supplementation significantly increased the content of IL-1β (P<0.05). However, TB supplementation in feed had no significant effects on the plasma content of GSH, HSP70, IL-8 and the activity of T-AOC (P>0.05). The possible mechanism was that TB activated PI3K/Akt/Nrf2 and inhibits the NF-κB signaling pathway, further regulating the mRNA levels of key genes with antioxidant capacity and the inflammatory response; for example, it increased the mRNA levels of Nrf2, Cu/Zn-SOD, HO-1, CAT, Akt, PI3K, GPx, IL-10, and TGF-β and decreased the mRNA levels of NF-κB and TNF-α (P<0.05). In addition, 0.06%-0.15% TB supplementation significantly increased the mRNA levels of IL-1β (P<0.05). TB supplementation in feed had no significant effects on the mRNA levels of HSP70, Mn-SOD and IL-8 (P>0.05). Evidence was presented that TB supplementation decreased the mortality rate caused by Aeromonas hydrophila challenge. In pathological examination, TB supplementation prevented hepatic and intestinal damage. Generally, TB supplementation improved the growth performance of juvenile blunt snout bream. Furthermore, TB supplementation activated PI3K/Akt/Nrf2 and inhibited the NF-κB signaling pathway, regulating health status and preventing hepatic and intestinal damage.

Dietary berberine can ameliorate glucose metabolism disorder of Megalobrama amblycephala exposed to a high-carbohydrate diet

Blunt snout bream (Megalobrama amblycephala) were randomly assigned into three diets: normal-carbohydrate diet (NCD, 30% carbohydrate, w/w), high-carbohydrate diet (HCD, 43% carbohydrate), and HCB (HCD supplemented with 50 mg/kg berberine (BBR)). After 10 weeks' feeding trial, the results showed that higher levels of plasma glucose, triglyceride, and total cholesterol were observed in HCD-fed fish than in NCD-fed fish, while HCB feeding significantly ameliorated this effect. Moreover, HCB feeding remarkably reversed HCD-induced hepatic glycogen and lipid contents. In insulin signaling, BBR inclusion restored HCD-induced suppression of insulin receptor substrate mRNA expression and elevation of forkhead transcription factor 1 mRNA expression. In glucose metabolism, upregulated glucose transporter 2 and glycogen synthase mRNA expressions in the HCD group were observed compared to the NCD group. However, BBR adding reduced the mRNA expressions of glycogen synthase, phosphoenolpyruvate carboxykinase, and glucose-6-phosphatase and increased the transcriptional levels of glucose transporter 2 and pyruvate kinase. In lipid metabolism, BBR supplementation could reverse downregulated hepatic carnitine palmitoyl transferase I mRNA expression and upregulated hepatic acetyl-CoA carboxylase and fatty acid synthetase mRNA expressions in the HCD group. Taken together, it demonstrates that BBR could improve glucose metabolism of this species via enhancing liver's glycolysis and insulin signaling, while inhibiting liver's glycogen synthesis and gluconeogenesis. It also indicates that BBR could reduce the metabolic burden of the liver by inhibiting fat synthesis and promoting lipid decomposition, and then enhance fat uptake in peripheral tissues.

Molecular characterization and expression of sirtuin 2, sirtuin 3, and sirtuin 5 in the Wuchang bream (Megalobrama amblycephala) in response to acute temperature and ammonia nitrogen stress

This study sought to characterize sirtuin 2 (sirt2), sirtuin 3 (sirt3), and sirtuin 5 (sirt5) in Megalobrama amblycephala (M. amblycephala) by cloning the open reading frame (ORF) of sirt2, sirt3, and sirt5. The full-lengths of the resulting M. amblycephala sirt2, sirt3, and sirt5 cDNA sequences were 1845, 1534, and 1920 bp, respectively, with 92%, 98%, and 91% similarities to Danio rerio sequences. Based on our bioinformatic analyses and predictions, the sirt2 and sirt3 genes of M. amblycephala were classified within the Sir2 I family, whereas sirt5 belonged to the Sir2 III family. Furthermore, sirt2, sirt3, and sirt5 were widely distributed in different M. amblycephala tissues. Particularly, sirt2 and sirt5 were highly expressed in gills, intestines, and liver (P < 0.05), whereas sirt3 was highly expressed in gills, kidney, liver, and spleen (P < 0.05). A 2 × 2 factorial experiment was also conducted to analyze sirt2, sirt3, and sirt5 expression patterns in response to acute temperature (25 and 32 °C) and ammonia nitrogen (0 and 20 mg/L) stress. Notably, these two stressors were found to interactively affect sirt2, sirt3, and sirt5 expression patterns in M. amblycephala liver. At the higher water temperature (32 °C) and ammonia nitrogen concentration (20 mg/L) tested herein, sirt2, sirt3, and sirt5 had similar expression levels and exhibited a down-regulation trend at 6 and 48 h post-stress but became up-regulated thereafter to counteract the stressors at 96 h post-stress.

The immunoreaction and antioxidant capacity of juvenile blunt snout bream (Megalobrama amblycephala) involves the PI3K/Akt/Nrf2 and NF-κB signal pathways in response to dietary methionine levels

A 75-day rearing trail was designed to evaluate the immunoreaction and antioxidant capacity of juvenile blunt snout bream in response to dietary methionine levels. Three practical diets were extruded to feed juveniles with graded methionine levels (0.40%, 0.84% and 1.28% dry matter). The data indicated that the plasma concentrations of immunoglobulin M (IgM), complement component 3 (C3) and glutathione (GSH) in the 0.84% methionine diet were markedly upper than those in the 0.40% group (P < 0.05). The activities of plasma antioxidant parameters involving catalase (CAT), total superoxide dismutase (T-SOD), total antioxidant capacity (T-AOC) and glutathione peroxidase (GPx) were significantly increased by the 0.84% diet compared with the 0.40% diet, whereas plasma alanine aminotransferase (ALT) and malondialdehyde (MDA) levels were significantly induced by 0.40% methionine (P < 0.05). Compared with the 0.40% group, 0.84% dietary methionine dramatically upregulated the mRNA expression levels of protein kinase B (Akt), phosphoinositide 3-kinase (PI3K) and nuclear factor erythroid 2-related factor 2 (Nrf2) pathway related genes including CAT, manganese superoxide dismutase (Mn-SOD), heme oxygenase 1 (HO-1) and glutathione peroxidase-1 (GPx-1) in the kidney and liver, and downregulated Kelch-like ECH-associated protein 1 (Keap1) mRNA levels (P < 0.05). Compared with the 0.40% group, the 0.84% dietary methionine strikingly suppressed the mRNA levels of renal and hepatic nuclear factor-kappa B (NF-κB) and pro-inflammatory cytokines (interleukin 1β (IL-1β), tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6)), however, improved the mRNA expression levels of anti-inflammatory cytokines involved renal and hepatic transforming growth factor-β (TGF-β) and hepatic interleukin 10 (IL-10) (P < 0.05). Renal IL-10 and interleukin 8 (IL-8) mRNA expression levels were not markedly influenced by experimental diets (P > 0.05). Dietary methionine (0.84%) significantly upregulated renal and hepatic heat stress protein 70 (Hsp70), renal B-cell lymphoma-2 (Bcl-2) gene expression levels compared with the 0.40% diet (P < 0.05). In a word, the data represented that 0.84% dietary methionine could enhance the immune and antioxidant capacity of this fish species by inducing PI3K/Akt/Nrf2 pathway and inhibiting NF-κB pathway.

Spiraeoside protects human cardiomyocytes against high glucose-induced injury, oxidative stress, and apoptosis by activation of PI3K/Akt/Nrf2 pathway

The present study aimed to explore the effect of spiraeoside, an active quercetin glucoside, on diabetic cardiomyopathy in vitro. Our results showed that spiraeoside attenuated high glucose (HG)-induced reduction of cell viability and increased myocardial enzymes lactate dehydrogenase and aspartate aminotransferase in AC16 cells. Spiraeoside exerted antioxidant activity in HG-induced AC16 cells as spiraeoside inhibited reactive oxygen species and malondialdehyde production and increased activities of superoxide dismutase, glutathione peroxidase, and catalase. Spiraeoside prevented HG-induced apoptosis of AC16 cells. HG stimulation-caused the decrease in the expression levels of p-Akt, nuclear Nrf2, and HO-1 was elevated after spiraeoside treatment in AC16 cells. However, the effects of spiraeoside were reversed by LY294002. In conclusion, spiraeoside protected AC16 cells against HG-induced oxidative stress, cell injury, and apoptosis. The protective effect of spiraeoside was regulated by the PI3K/Akt/Nrf2 signaling pathway.

Dietary selenium enhances the growth and anti-oxidant capacity of juvenile blunt snout bream (Megalobrama amblycephala)

Sodium selenite was added to basal diet at five levels (0.10, 0.42, 0.67, 1.06 and 1.46 mg Se/kg) and fed fish for 8 weeks. The dietary selenium requirement of juvenile blunt snout bream (Megalobrama amblycephala) was quantified. Dietaryseleniums at 0.67-1.06 mg Se/kg improved weight gain rate, specific growth rate and feed efficiency. The optimal amount was 0.96 mg/kg, for which the specific growth rate was 1.798%/day and the weight gain rate was 173.852% (p < 0.05). Se deposition in muscle was increased (p < 0.05) at ≥0.67 mg/kg, but moisture, protein, lipid and ash content were not affected. Physiological status and lipid metabolism were improved by 1.06-1.46 mg/kg dietary selenium based on total protein and albumin in plasma, and total cholesterol and triglycerides (p < 0.05). Activities of hepatic anti-oxidant enzymes catalase, total superoxide dismutase, glutathione peroxidase and reduced glutathione were enhanced at Se1.06 (p < 0.05). However, malondialdehyde content was lowered at Se1.06 (p < 0.05). Expression of anti-inflammatory cytokines, nuclear factor erythroid 2-related factor 2 (Nrf2) and kelch-like ECH-associated protein 1 (Keap-1) in liver were elevated at Se1.06 (p < 0.05), as were mRNA levels of glutathione peroxidase, copper zinc superoxide dismutase and catalase. Expression of pro-inflammatory cytokines, interleukin 8, tumour necrosis factor-α and transforming growth factor-β were inhibited at 0.67-1.46 mg/kg (p < 0.05). In general, 0.96 mg/kg was optimal, and optimal selenium enhanced antioxidant stress tolerance and anti-inflammatory ability.

Magnolol Prevents Acute Alcoholic Liver Damage by Activating PI3K/Nrf2/PPARγ and Inhibiting NLRP3 Signaling Pathway

Alcoholic liver damage (ALD) is a toxic liver damage caused by excessive drinking. Oxidative stress is one of the most crucial pathogenic factors leading to ALD. Magnolol is one of the main active constituents of traditional Chinese medicine Magnolia officinalis, which has been reported to possess many pharmacological effects including anti-inflammatory, anti-oxidant, and anti-tumor. However, the effects of magnolol on ALD remain unclear. In this study, we firstly evaluated the protective effects of magnolol on ALD, and then tried to clarify the mechanism underlying the pharmacological activities. AST, ALT, GSH-Px, and SOD were detected by respective kits. Histopathological changes of liver tissue were analyzed by H&E staining. The activities of PI3K, Nrf2, and NLRP3 signaling pathways activation were detected by western blotting analysis. It was showed that alcohol-induced ALT and AST levels were significantly reduced by magnolol, but the antioxidant enzymes of GSH-Px and SOD levels were significantly increased. Magnolol attenuated alcohol-induced pathologic damage such as decreasing hepatic cord swelling, hepatocyte necrosis, and inflammatory cell infiltration. Furthermore, it was found that magnolol inhibited oxidative stress through up-regulating the activities of HO-1, Nrf2, and PPARγ and the phosphorylation of PI3K and AKT. And magnolol also decreased inflammatory response by inhibiting the activation of NLRP3inflammasome, caspase-1, and caspase-3 signaling pathway. Above results showed that magnolol could prevent alcoholic liver damage, and the underlying mechanism was through activating PI3K/Nrf2/PPARγ signaling pathways as well as inhibiting NLRP3 inflammasome, which also suggested magnolol might be used as a potential drug for ALD.

FGF10 Enhances Peripheral Nerve Regeneration via the Preactivation of the PI3K/Akt Signaling-Mediated Antioxidant Response

The process of axonal regeneration after peripheral nerve injury (PNI) is slow and mostly incomplete. Previous studies have investigated the neuroprotective effects of fibroblast growth factor 10 (FGF10) against spinal cord injury and cerebral ischemia brain injury. However, the role of FGF10 in peripheral nerve regeneration remains unknown. In this study, we aimed to investigate the underlying therapeutic effects of FGF10 on nerve regeneration and functional recovery after PNI and to explore the associated mechanism. Our results showed that FGF10 administration promoted axonal regeneration and functional recovery after nerve damage. Moreover, exogenous FGF10 treatment also prevented SCs from excessive oxidative stress-induced apoptosis, which was probably related to the activation of phosphatidylinositol-3 kinase/protein kinase B (PI3K/Akt) signaling. The inhibition of the PI3K/Akt pathway by the specific inhibitor LY294002 partially reversed the therapeutic effects of FGF10 both in vivo and in vitro. Thus, from our perspective, FGF10 may be a promising therapeutic drug for repairing sciatic nerve damage through countering excessive oxidative stress-induced SC apoptosis.

Cytotoxic effects, inflammatory response and apoptosis induction of cyclophosphamide in the peripheral blood leukocyte of blunt snout bream (Megalobrama amblycephala)

The present study was aimed to evaluate the effects of the cyclophosphamide (CY) exposure (Control, 0.032, 0.32, 1.0, 1.6 and 3.2 mg/mL) on the damage in the peripheral blood leukocytes of blunt snout bream for 24 h, which including cell viability, apoptosis, lactate dehydrogenase (LDH) release, mitochondrial membrane potential (Δѱm), ROS, antioxidant enzyme activity and the relative mRNA levels of apoptosis. Results showed that cell viability and Δѱm effects of CY were greatly reduced, and occurred in a dose-dependent manner. CY exposure (0.32-3.2 mg/mL) significantly increased the LDH release and induced apoptosis accompanied by ΔΨm disruption and ROS generation compared to the control. The cellular ROS was significantly increased with increase of CY level from 0.032 mg/mL to 1 mg/mL and the plateau occurred at 0.32 mg/mL. Additionally CY exposure led to oxidative stress as evidenced by significantly the decrease of SOD and CAT and increase of MDA concentration after treating cells with 3.2 mg/mL of CY. Besides, the relative mRNA levels of caspase-3 in the dose of 0.032, 0.32 mg/mL CY, caspase-9 and interleukins-1β (IL-1β) in the dose of 0.32 mg/mL CY, tumor necrosis factor-alpha (TNF-α) in the dose of 0.032 mg/mL CY significantly higher than that of the control. In conclusion, 0.32-3.2 mg/mL CY could lead to cytotoxic effect, inflammatory response and induce the apoptosis of the peripheral blood leukocyte of Megalobrama amblycephala.

Feeding restriction alleviates high carbohydrate diet-induced oxidative stress and inflammation of Megalobrama amblycephala by activating the AMPK-SIRT1 pathway

This study investigated the effects of restricted feeding on the growth performance, oxidative stress and inflammation of Megalobrama amblycephala fed high-carbohydrate (HC) diets. Fish (46.94 ± 0.04 g) were randomly assigned to four groups containing the satiation of a control diet (30% carbohydrate) and three satiate levels (100% (HC1), 80% (HC2) and 60% (HC3)) of the HC diets (43% carbohydrate) for 8 weeks. Results showed that HC1 diet remarkably decreased final weight (FW), weight gain rate (WGR), specific growth rate (SGR), feed conversion ratio (FCR), hepatic activities of total anti-oxidation capacity (T-AOC), superoxide dismutase (SOD) and catalase (CAT), the AMP/ATP ratio, the p-AMPKα/t-AMPKα ratio, sirtuin-1 (SIRT1) protein expression and hepatic transcriptions of AMPKα2, SIRT1, nuclear factor erythroid 2-related factor 2 (Nrf2), catalase (CAT), manganese superoxide dismutase (Mn-SOD), glutathione peroxidase 1 (GPx1) and interleukin10 (IL 10) compared to the control group, whereas the opposite was true for protein efficiency ratio (PER), nitrogen retention efficiency (NRE), energy retention efficiency (ERE), plasma glucose levels, alanine transaminase (AST) and aspartate aminotransferase (ALT) activities, hepatic contents of malondialdehyde (MDA), tumour necrosis factor α (TNF α) and interleukin 1β (IL 1β), ATP and AMP contents and hepatic transcriptions of kelch-like ECH associating protein 1 (Keap1), IkB kinase α (IKK α), nuclear factor kappa B (NF-κB), TNF α, IL 1β, interleukin 6 (IL 6) and transforming growth factor β (TGF β). As for the HC groups, fish fed the HC2 diet obtained relatively high values of SGR, PER, NRE, ERE, hepatic activities of T-AOC, SOD and CAT, the AMP/ATP ratio, the p-AMPKα/t-AMPKα ratio, SIRT1 protein expression and hepatic transcriptions of AMPKα2, Nrf2, CAT, copper/zinc superoxide dismutase (Cu/Zn-SOD), Mn-SOD, GPx1, glutathione S-transferase (GST) and interleukin10 (IL 10), while the opposite was true for hepatic content of IL 6 and transcription of IKK α. Overall, an 80% satiation improved the growth performance and alleviated the oxidative stress and inflammation of blunt snout bream fed HC diets via the activation of the AMPK-SIRT1 pathway and the up-regulation of the activities and transcriptions of Nrf2-modulated antioxidant enzymes coupled with the depression of the levels and transcriptions of the NF-κB-mediated pro-inflammatory cytokines.

High glucose affected respiratory burst activity of peripheral leukocyte via G6PD and NOX inhibition in Megalobrama amblycephala

High glucose levels are known to impair growth and immune function in fish. Here we investigated the role of glucose-6-phosphate dehydrogenase (G6PD) and NADPH oxidase (NOX) in high glucose-associated impairment of leukocyte respiratory burst activity in Megalobrama amblycephala. We cultured peripheral leukocytes isolated from M. amblycephala with media containing no glucose (non-glucose group), 11.1 mmol/L d-glucose (physiologic glucose group), 22.2 mmol/L d-glucose (high-glucose group), or 11.1 mmol/L d-glucose + 100 μmol/L dehydroepiandrosterone (DHEA) (DHEA-treated group). After 24 h, we assayed production of reactive oxygen species (ROS) as a measure of respiratory burst function as well as activity of G6PD and NOX. The high-glucose group and DHEA-treated group showed significantly reduced respiratory burst function, reduced production of ROS, and reduced G6PD and NOX activity at 24 h, compared to the non-glucose and physiologic glucose groups (P < 0.05). The degree of impairment was similar between high-glucose and DHEA-treated groups (P > 0.05). These findings suggest that reduced NADPH availability likely underlies the suppression of respiratory burst function in M. amblycephala leukocytes exposed to high glucose levels.

High-fat-diet-induced inflammation depresses the appetite of blunt snout bream (Megalobrama amblycephala) through the transcriptional regulation of leptin/mammalian target of rapamycin

The aim of this article was to investigate the mechanism of appetite suppression induced by high-fat diets (HFD) in blunt snout bream (Megalobrama amblycephala). Fish (average initial weight 40·0 (sem 0·35) g) were fed diets with two fat levels (6 and 11 %) with four replicates. HFD feeding for 30 d could significantly increase the weight gain rate, but feeding for 60 d cannot. Food intake of M. amblycephala began to decline significantly in fish fed the HFD for 48 d. HFD feeding for 60 d significantly reduced the expression of neuropeptide Y and elevated the expression of cocaine- and amphetamine-regulated transcript (CART), actions both in favour of suppression of appetite. The activation of fatty acid sensing was partly responsible for the weakened appetite. In addition, inflammatory factors induced by the HFD may be involved in the regulation of appetite by increasing the secretion of leptin and then activating the mammalian target of rapamycin (mTOR). Lipopolysaccharide (LPS, 2·0 mg/kg of fish weight) was administered to induce inflammation, and sampling was performed after 3, 6, 9, 12, 18, 24 and 48 h of LPS injection. Within 6-24 h of LPS injection, the food intake and appetite of M. amblycephala decreased significantly, whereas the mRNA expression of leptin and mTOR increased significantly. Our results indicate that inflammatory cytokines may be the cause of appetite suppression in M. amblycephala fed a HFD.

Sirt1/Nrf2 signalling pathway prevents cognitive impairment in diabetic rats through anti‑oxidative stress induced by miRNA‑23b‑3p expression

In the present study the exact roles and mechanisms underlying the effect of miRNA‑23b‑3p on the cognitive impairment of diabetic rats were investigated. The in vivo model of diabetes was established in Wistar rats via a single injection of streptozotocin (STZ). Cognitive function was evaluated using a Morris water maze test. Oxidative stress was measured using ELISA kits, and the protein expression levels of B‑cell lymphoma 2‑associated X protein, silent information regulator 1 (SIRT1), nuclear factor erythroid 2‑related factor 2 (Nrf2) and GAPDH were measured by western blot analysis. Micro (mi)RNA‑23b‑3p mimics were employed to increase miRNA‑23b‑3p expression in the in vitro model. Overexpression of miRNA‑23b‑3p increased oxidative stress (as indicated by the levels of glutathione peroxidase, glutathione, superoxide dismutase and malondialdehyde) and apoptosis in neurocytes following high‑glucose treatment. The overexpression of miRNA‑23b‑3p also suppressed SIRT1 and Nrf2 expression in neurocytes following high‑glucose treatment; it also promoted the SIRT1‑induced inhibition of apoptosis and oxidative stress. The promotion of SIRT1 also decreased the effect of miRNA‑23b‑3p on cognitive impairment in diabetic rats. In conclusion, miRNA‑23b‑3p prevents the cognitive impairment of diabetic rats via anti‑oxidative stress effects and the Sirt1/Nrf2 signaling pathway.