Effects of Auricularia auricula-judae (Bull.) Quél. polysaccharide acid hydrolysate on glucose metabolism in diabetic mice under oxidative stress.

BACKGROUND: Oxidative stress can lead to uncontrolled glucose metabolism and, thus, diabetes. Auricularia auricula-judae (Bull.) Quél. polysaccharides possess biological activities, such as antioxidant and hypoglycemic effects, but their mechanism of their acid hydrolysates on oxidative stress-injured glucose metabolism disorders is unclear. PURPOSE: Using diabetic mice, we investigated the effect of the acid hydrolysate of polysaccharides from Auricularia auricula-judae (Bull.) Quél. on improving diabetes. STUDY DESIGN AND METHODS: The structural information of sample polysaccharides was measured by high performance gel permeation chromatography, nuclear magnetic resolution, and high performance liquid chromatography. The diabetic model was established by intraperitoneal injection of streptozotocin. For eight consecutive weeks, the mice were orally administered sample polysaccharides (100, 200, and 300 mg/kg b.w. per day) for intervention. The improvement effect of the samples on diabetes was explored by detecting the changes in biochemical indicators in mice, and the underlying mechanism was studied by transcriptomic and metabolomic analysis. RESULTS: The results showed that acid hydrolysate of Auricularia auricula-judae (Bull.) Quél. polysaccharides consisted mainly of mannose, xylose, glucuronic acid, and glucose; its weight-averaged molecular weight was 6.3842 × 104 Dalton, its number average molecular weight was 2.9594 × 104 Dalton; and the molecule contained α-Glc(1→4)-, ß-Glc(1→3)-, and ß-Man(1→4)-linked glycosidic bonds. A total of 100 mg/kg b.w. per day sample was the best intervention concentration. After eight weeks of intervention, the sample polysaccharides significantly reduced dynamic blood glucose and serum lipids, enhanced antioxidant enzyme activities, promoted glucagon like peptide-1 and insulin secretion, improved insulin sensitivity and alleviated insulin resistance in diabetic mice. Transcriptomic and metabolomic analyses showed that sample polysaccharides was able to ameliorate disorders of glucose metabolism by modulating gene expression such as glucokinase; and modulate the state of oxidative stress in mice in vivo by regulating the glutathione metabolism pathway. CONCLUSION: Acid hydrolysate of Auricularia auricula-judae (Bull.) Quél. polysaccharides improved glucose metabolism disorders by slowing down the oxidative stress injury in mice, thereby alleviating diabetes. This study provided a basis for determining the underlying mechanism of the antidiabetic effect of Auricularia auricula-judae (Bull.) Quél. polysaccharides, which would significantly improve the deep development and application of these materials in diabetes control.

Effects of synergistic Fenton-microwave treatment on the antioxidant stress of soluble polysaccharides and the physicochemical properties of insoluble polysaccharides from Gelidium amansii.

In this study, we individually obtained crude Gelidium amansii water-soluble polysaccharides and water-insoluble polysaccharides (GAIPs) using an improved Fenton-microwave synergistic treatment. The former were purified by alcohol precipitation and deproteinization to obtain Gelidium amansii water-soluble polysaccharides (GASPs), and their effects on the oxidative stress resistance of Caenorhabditis elegans were investigated. GAIPs were studied for their physicochemical properties, including hydration characteristics, adsorption, and cation-exchange capacity. The results showed that compared with the negative control, 1.0 mg/mL GASPs significantly upregulated (>1.70-fold) the expression of antioxidant-related genes, such as daf-16, sir-2.1, and skn-1 (p < 0.05), which prolonged the mean survival time and increased the mean number of head bobbing (p < 0.05). The hydration characteristics and oil-holding capacity of GAIPs were lower than those of G. amansii powder (GAP) and G. amansii filtrate residue (GADP). However, the adsorption capacity of GAIPs for cholesterol (pH 7.0) and sodium cholate and the cation-exchange capacity were significantly better than those of GAP (5.17, 13.16 & 1.63 times, p < 0.05) and GADP (8.42, 6.39, & 2.05 times, p < 0.05). To conclude, the synergistic Fenton-microwave treatment contributed to the increase in the oxidative stress resistance of GASPs and improved the adsorption capacity and cation-exchange capacity of GAIPs.

Computer-Aided Diagnosis of Complications After Liver Transplantation Based on Transfer Learning.

Liver transplantation is one of the most effective treatments for acute liver failure, cirrhosis, and even liver cancer. The prediction of postoperative complications is of great significance for liver transplantation. However, the existing prediction methods based on traditional machine learning are often unavailable or unreliable due to the insufficient amount of real liver transplantation data. Therefore, we propose a new framework to increase the accuracy of computer-aided diagnosis of complications after liver transplantation with transfer learning, which can handle small-scale but high-dimensional data problems. Furthermore, since data samples are often high dimensional in the real world, capturing key features that influence postoperative complications can help make the correct diagnosis for patients. So, we also introduce the SHapley Additive exPlanation (SHAP) method into our framework for exploring the key features of postoperative complications. We used data obtained from 425 patients with 456 features in our experiments. Experimental results show that our approach outperforms all compared baseline methods in predicting postoperative complications. In our work, the average precision, the mean recall, and the mean F1 score reach 91.22%, 91.70%, and 91.18%, respectively.

Preparation of Auricularia auricula polysaccharides and their protective effect on acute oxidative stress injury of Caenorhabditis elegans.

This research enhanced the extraction procedure for Auricularia auricula crude polysaccharides by utilizing a modified Fenton reagent as a solvent, and obtained A. auricula polysaccharides (AAPs-VH) via alcohol precipitation and deproteinization. The HPLC profile revealed that the purified AAPs-VH using Sepharose 6FF was mainly a heteropolysaccharide, consisting primarily of mannose, glucuronic acid, glucose, and xylose. The Mw and Mn of the purified AAPs-VH were 87.646 kDa and 48.854 kDa, respectively. The FT-IR and NMR spectra revealed that the purified AAPs-VH belonged to pyranose and were mainly formed by (1 â†’ 3)-linked-ß-D glucan formation. In vivo experiments conducted with Caenorhabditis elegans, AAPs-VH was found to notably influence the lifespan, improve the antioxidant system, and decrease the level of cell apoptosis. This might be achieved by up-regulating the expression of genes in the IIS and TOR pathways. The study concludes that the modified Fenton reagent can increase Auricularia auricula polysaccharide solubleness and active sites, which may be an essential prompt for future studies.

ß-Hydroxybutyrate inhibits apoptosis in bovine neutrophils through activating ERK1/2 and AKT signaling pathways.

Ketosis in dairy cows, a common metabolic disorder during the peripartal period, is accompanied by systemic inflammation and high concentrations of blood ß-hydroxybutyrate (BHB). Neutrophil apoptosis plays a key role in maintaining the balance of inflammation and functional capacity of circulating neutrophils in ketotic cows. The kinases ERK1/2 and AKT, as well as their downstream Bcl-2 family-mediated mitochondrial signaling, are important apoptosis-regulating pathways in neutrophils. The objective of our study was to investigate the effects of BHB on neutrophil apoptosis and the underlying regulatory mechanisms during ketosis. Neutrophils were isolated from 5 multiparous cows (within 3 wk postpartum) with serum BHB concentrations <0.6 mM and glucose concentrations >3.5 mM. In a series of experiments, neutrophils were treated with increasing concentrations of BHB (0, 0.6, 2, and 3 mM for 10 h) and time (0, 2, 4, 6, 8, and 10 h with 2 mM). Subsequently, a 2 mM BHB dose was used to challenge neutrophils for 8 h. Apoptosis rate of neutrophils and protein abundance of cleaved caspase 3 were lower after BHB treatment. Treatment with BHB decreased protein and mRNA abundance of the pro-apoptotic genes Bax (BAX) and Bad (BAD), whereas it increased mitochondrial membrane potential (MMP) and protein and mRNA of the anti-apoptotic genes Bcl-xL (BCL2L1) and Mcl-1 (MCL1). This indicated that a mitochondrial pathway was involved in the inhibition of neutrophil apoptosis via BHB. In addition, both SCH772984 (an inhibitor of the ERK1/2 signaling pathway) and MK-2206 (an inhibitor of the AKT signaling pathway) alleviated the BHB-induced anti-apoptotic function of the Bcl-2 family and the inhibition of MMP. Overall, our data demonstrated that high concentrations of BHB inhibit apoptosis in bovine neutrophils by activating the ERK1/2 and AKT signaling pathways. These findings provide a theoretical basis for the understanding of systemic inflammation in ketotic cows.

Free fatty acids promote degranulation of azurophil granules in neutrophils by inducing production of NADPH oxidase-derived reactive oxygen species in cows with subclinical ketosis.

Subclinical ketosis (SCK) in dairy cows, a common metabolic disorder during the peripartal period, is accompanied by systemic inflammation. Excessive release of azurophil granule (AG) contents during degranulation of polymorphonuclear neutrophils (PMN) could contribute to systemic inflammation in SCK cows. Although the increase in blood free fatty acids (FFA) in SCK cows may promote AG degranulation from PMN, the underlying mechanisms are unclear. Thirty multiparous cows (within 3 wk postpartum) with similar lactation numbers (median = 3, range = 2-4) and days in milk (median = 6, range = 3-15) were classified based on serum ß-hydroxybutyrate (BHB) level as control (n = 15, BHB < 0.6 mM) or SCK (n = 15, 1.2 mM < BHB < 3.0 mM). Cows with SCK had greater levels of serum haptoglobin, serum amyloid A, IL-1ß, IL-6, IL-8 and tumor necrosis factor-α. These proinflammatory factors had strong positive correlations with myeloperoxidase (MPO), a marker protein of PMN AG, whose content was greater in the serum of SCK cows. Both the number of AG and the protein abundance of MPO were lower in PMN isolated from SCK cows. Additionally, we found a greater ratio of blood CH138A+/CD63high cells and greater mean fluorescence intensity of CD63 on the PMN membrane, further confirming the greater degree of AG degranulation in cows with SCK. In vitro FFA dose response (0, 0.3, 0.6, 1.2, and 2.4 mM for 4 h) and time course (0, 0.5, 1, 2, and 4 h with 0.6 mM) experiments were performed on PMN isolated from control cows. The increase in MPO content in extracellular supernatant resulting from those experiments led to the selection of 0.6 mM FFA for 1 h duration as conditions for subsequent studies. After FFA treatment, release of intracellular MPO was increased along with increased levels of CD63 mean fluorescence intensity on the PMN membrane, confirming that FFA promoted degranulation of AG. In addition, FFA treatment increased reactive oxygen species (ROS) production by PMN, an effect that was attenuated by incubation with diphenyleneiodonium chloride (DPI), a NADPH oxidase-derived ROS inhibitor. The mitochondrial-derived ROS inhibitor carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP) did not affect ROS in response to FFA treatment. Treatment with FFA increased p47 phosphorylation and mRNA abundance of NCF1, NCF2, and CYBB in PMN. Furthermore, DPI, but not FCCP, dampened the degranulation of PMN AG induced by FFA in vitro. These data suggested that the degranulation of AG in PMN induced by FFA was mediated by NADPH oxidase-derived ROS. As verified ex vivo, PMN from SCK cows had greater levels of ROS, phosphorylation of p47, and mRNA abundance of NCF1, NCF2, and CYBB. Overall, the present study revealed that high blood concentrations of FFA in SCK cows induce the production of NADPH oxidase-derived ROS, thereby promoting degranulation of AG in PMN. The stimulatory effect of FFA on the release of AG content during degranulation, especially MPO, provides a new insight into the systemic inflammation experienced by peripartal cows with SCK.

ß-hydroxybutyrate enhances bovine neutrophil adhesion by inhibiting autophagy.

Introduction: Subclinical ketosis (SCK) in dairy cows, a common metabolic disorder during the perinatal period, is accompanied by systemic inflammation and a high concentration of blood ß-hydroxybutyrate (BHB). BHB induced adhesion of neutrophils may play a crucial role in the development of systemic inflammation in SCK cows. Autophagy, an intracellular degradation system, regulates the recycling of membrane adhesion molecules and may be involved in BHB regulating adhesion and pro-inflammatory activation of bovine neutrophils. Thus, the objective of this study was to determine the relationship between BHB, autophagy, and neutrophil adhesion. Results and discussion: Here, elevated abundance of serum amyloid A, haptoglobin, C-reactive protein, interleukin-1ß, interleukin-6, and tumor necrosis factor-α were found in SCK cows, and all these pro-inflammatory factors had a strong positive correlation with serum BHB. After BHB treatment, the number of adherent neutrophils and the adhesion associated protein abundance of both total and membrane CD11a, CD11b, and CD18 was greater, confirming that BHB promoted the adhesion of bovine neutrophils. However, the mRNA abundance of ITGAL (CD11a), ITGAM (CD11b), and ITGB2 (CD18) did not show a significant difference, suggesting that the degradation of adhesion molecules may be impaired. Transmission electron microscopy revealed a decreased number of autophagosomes and a decrease in mRNA abundance of SQSTM1 (p62) and MAP1LC3B (LC3) after BHB treatment. In parallel, protein abundance of p62 increased while the ratio of protein LC3 II to LC3 I decreased after BHB treatment, indicating that BHB inhibits autophagy of bovine neutrophils. To confirm the regulatory role of autophagy in BHB promoting neutrophil adhesion, we used an autophagy activator rapamycin (RAPA). Data showed that RAPA relieved the inhibitory effect on autophagy and the promotive effect on cell adhesion induced by BHB. Importantly, BHB inhibited the colocalization of LC3 and CD11b, which was relieved by RAPA, further confirming the regulatory role of autophagy in the recycling of the above adhesion molecules. Furthermore, BHB treatment increased the mRNA abundance and the release of pro-inflammatory factors IL-1B, IL-6, and TNF of bovine neutrophils, and these effects were attenuated by RAPA. Overall, the present study revealed that BHB promotes the adhesion of bovine neutrophils by inhibiting autophagy.