Xyloketal B alleviates cerebral infarction and neurologic deficits in a mouse stroke model by suppressing the ROS/TLR4/NF-κB inflammatory signaling pathway.

Xyloketal B (Xyl-B) is a novel marine compound isolated from mangrove fungus Xylaria sp. We previously demonstrated that pretreatment with Xyl-B exerted neuroprotective effects and attenuated hypoxic-ischemic brain injury in neonatal mice. In the present study we investigated the neuroprotective effects of pre- and post-treatment with Xyl-B in adult mice using a transient middle cerebral artery occlusion (tMCAO) model, and explored the underlying mechanisms. Adult male C57 mice were subjected to tMCAO surgery. For the pre-treatment, Xyl-B was given via multiple injections (12.5, 25, and 50 mg·kg-1·d-1, ip) 48 h, 24 h and 30 min before ischemia. For the post-treatment, a single dose of Xyl-B (50 mg/kg, ip) was injected at 0, 1 or 2 h after the onset of ischemia. The regional cerebral perfusion was monitored using a laser-Doppler flowmeter. TTC staining was performed to determine the brain infarction volume. We found that both pre-treatment with Xyl-B (50 mg/kg) and post-treatment with Xyl-B (50 mg/kg) significantly reduced the infarct volume, but had no significant hemodynamic effects. Treatment with Xyl-B also significantly alleviated the neurological deficits in tMCAO mice. Furthermore, treatment with Xyl-B significantly attenuated ROS overproduction in brain tissues; increased the MnSOD protein levels, suppressed TLR4, NF-κB and iNOS protein levels; and downregulated the mRNA levels of proinflammatory cytokines, including IL-1ß, TNF-α, IL-6 and IFN-γ. Moreover, Xyl-B also protected blood-brain barrier integrity in tMCAO mice. In conclusion, Xyl-B administered within 2 h after the onset of stroke effectively protects against focal cerebral ischemia; the underlying mechanism may be related to suppressing the ROS/TLR4/NF-κB inflammatory signaling pathway.

Xyloketal B attenuates atherosclerotic plaque formation and endothelial dysfunction in apolipoprotein e deficient mice.

Our previous studies demonstrated that xyloketal B, a novel marine compound with a unique chemical structure, has strong antioxidant actions and can protect against endothelial injury in different cell types cultured in vitro and model organisms in vivo. The oxidative endothelial dysfunction and decrease in nitric oxide (NO) bioavailability are critical for the development of atherosclerotic lesion. We thus examined whether xyloketal B had an influence on the atherosclerotic plaque area in apolipoprotein E-deficient (apoE-/-) mice fed a high-fat diet and investigated the underlying mechanisms. We found in our present study that the administration of xyloketal B dose-dependently decreased the atherosclerotic plaque area both in the aortic sinus and throughout the aorta in apoE-/- mice fed a high-fat diet. In addition, xyloketal B markedly reduced the levels of vascular oxidative stress, as well as improving the impaired endothelium integrity and NO-dependent aortic vasorelaxation in atherosclerotic mice. Moreover, xyloketal B significantly changed the phosphorylation levels of endothelial nitric oxide synthase (eNOS) and Akt without altering the expression of total eNOS and Akt in cultured human umbilical vein endothelial cells (HUVECs). Here, it increased eNOS phosphorylation at the positive regulatory site of Ser-1177, while inhibiting phosphorylation at the negative regulatory site of Thr-495. Taken together, these findings indicate that xyloketal B has dramatic anti-atherosclerotic effects in vivo, which is partly due to its antioxidant features and/or improvement of endothelial function.

ClC-3 deficiency protects preadipocytes against apoptosis induced by palmitate in vitro and in type 2 diabetes mice.

Palmitate, a common saturated free fatty acid (FFA), has been demonstrated to induce preadipocyte apoptosis in the absence of adipogenic stimuli, suggesting that preadipocytes may be prone to apoptosis under adipogenic insufficient conditions, like type 2 diabetes mellitus (T2DM). ClC-3, encoding Cl(-) channel or Cl(-)/H(+) antiporter, is critical for cell fate choices of proliferation versus apoptosis under diseased conditions. However, it is unknown whether ClC-3 is related with preadipocyte apoptosis induced by palmitate or T2DM. Palmitate, but not oleate, induced apoptosis and increase in ClC-3 protein expression and endoplasmic reticulum (ER) stress in 3T3-L1 preadipocyte. ClC-3 specific siRNA attenuated palmitate-induced apoptosis and increased protein levels of Grp78, ATF4, CHOP and phosphorylation of JNK1/2, whereas had no effects on increased phospho-PERK and phospho-eIF2α protein expression. Moreover, the enhanced apoptosis was shown in preadipocytes from high-sucrose/fat, low-dose STZ induced T2DM mouse model with hyperglycemia, hyperlipidemia (elevated serum TG and FFA levels) and insulin resistance. ClC-3 knockout significantly attenuated preadipocyte apoptosis and the above metabolic disorders in T2DM mice. These data demonstrated that ClC-3 deficiency prevent preadipocytes against palmitate-induced apoptosis via suppressing ER stress, and also suggested that ClC-3 may play a role in regulating cellular apoptosis and disorders of glucose and lipid metabolism during T2DM.

Screening potential ligands of endothelin receptor A from Choerospondias axillaris and evaluation of their drug-like properties by affinity chromatographic methods.

Tibetan medicine is traditionally prescribed as crude extracts or mixtures owing to the theoretical basis with cross fertilization from other medical systems like Ayurveda and traditional Chinese medicine. This is challenged to elucidate the action mechanism and material foundation of Tibetan medicine due to lacking a method to confirm the bioactive compounds determining the therapy. This work created a new strategy for screening and evaluating the bioactive compounds against cardiovascular ailments from Choerospondias axillaris. It involved the immobilization of endothelin receptor A (ETAR) by a one-step covalent assay, the screening and identification of the bioactive compounds by ETAR column combined with tandem mass spectrometry, and the evaluation of their drug-like properties by calculating the efficiency indexes using the data collected by frontal analysis and adsorption energy distribution. The immobilized ETAR remained good stability in three weeks in terms of specificity and repeatability. Catechin, pinocembrin, and hyperoside were identified as potential ETAR ligands from Choerospondias axillaris with two types of binding sites on the immobilized receptor. Their association constants on the high and low affinity binding sites were (2.53 ± 0.11) × 105 and (9.94 ± 0.02) × 103 M-1 for catechin, (1.01 ± 0.12) × 106 and (7.40 ± 0.03) × 104 for hyperoside, and (2.05 ± 0.04) × 105 and (2.47 ± 0.09)× 104 M-1 for pinocembrin, respectively. Owing to the highest association constant, hyperoside presented a surface efficiency index of 7.95, and binding efficiency index of 20.7, and the ligand-lipophilicity efficiency of 1.38. These indicated that the three compounds were the main ingredients for the therapy of Choerospondias axillaris, and had potential to become lead compounds for anti-cardiovascular drugs based on drug-ETAR interaction. The immobilized receptor-based strategy is possible to become an alternative for screening and assessing bioactive compounds from Tibetan medicine.

Jaceosidin inhibits the progression and metastasis of NSCLC by regulating miR-34c-3p/Integrin α2ß1 axis.

Non-coding RNAs are crucial for cancer progression, among which miR-34c-3p has been demonstrated to be a tumor suppressor in non-small cell lung cancer (NSCLC). In this study, we attempt to identify flavonoids that can up-regulate miR-34c-3p expression, evaluate the anticancer activity of the flavonoids and explore its underlying mechanism in NSCLC cells. Six flavonoids were screened by RT-qPCR and we found that jaceosidin significantly increased miR-34c-3p expression in A549 cells. We found that jaceosidin inhibited the proliferation, migration and invasion of A549 and H1975 cells in a dose-relevant manner, indicated by cell counting kit (CCK-8) assay, wound healing assay, transwell assay and EdU assay, we observed that jaceosidin inhibited the proliferation, migration and invasion of A549 and H1975 cells in a dose-relevant manner. Further research suggested that miR-34c-3p bound to the transcriptome of integrin α2ß1 and then inhibited its expression, leading to the inhibitory effect on the migration and invasion of NSCLC. Our study sheds some light on anti-tumor of jaceosidin and provides a potential lead compound for NSCLC therapy.

Mallotus oblongifolius extracts ameliorate ischemic nerve damage by increasing endogenous neural stem cell proliferation through the Wnt/ß-catenin signaling pathway.

Mallotus oblongifolius (MO), an edible medicinal plant from Hainan in China, shows a wide range of bioactivities. The daily consumption of MO or its extracts has been observed to ameliorate ischemic nerve injury. However the mechanisms remain unclear. In this study, the effects of MO both in vitro and in vivo were investigated. The results indicated that MO improved the motor ability, neurosensory ability, balance and grasping ability of mice with ischemic injuries, induced by bilateral common carotid artery ligation (BCCAL). In addition, MO improved the morphology of neurons, resisted the loss of neurons, and enhanced the content of the nestin protein in the cerebral cortex and subgranular zone (SGZ) area. Furthermore, in the oxygen-glucose deprivation and reperfusion (OGD/R) treated cell model, MO could effectively activate the Wnt/ß-catenin signaling pathway and promote the proliferation of neural stem cells (NSCs) and increase the protein expression levels of ß-catenin and CyclinD1. Our results suggest that Mallotus oblongifolius may be used as nutraceuticals or functional foods to alleviate ischemic nerve damage and promote recovery from ischemic stroke.

Arjunic acid, a strong free radical scavenger from Terminalia arjuna.

This study was designed to investigate the antioxidant and free radical scavenging capacities of arjunic acid, an aglycone obtained from the fruit of medicine Terminalia Fruit. Liver microsomes, mitochondria, and red blood cells (RBCs) were prepared from Wistar rats. The antioxidant capacity was determined by the inhibitory effect on lipid peroxidation, hydrogen peroxide induced RBCs hemolysis, and RBCs autoxidative hemolysis. The free radical scavenging activity was tested by DPPH method and 2',7'-dichlorodihydrofluoresc in diacetate (DCFH(2)-DA) assay. Ascorbic acid was chosen as the positive controls. Results showed that arjunic acid was a strong antioxidant and a free radical scavenger, more potent than ascorbic acid, in microsomes lipid peroxidation, DPPH, hydrogen peroxide induced RBCs hemolysis, and (DCFH(2)-DA) assay (p < 0.05). However, no significant difference was observed in the RBCs autoxidative hemolysis assay (p > 0.05).

Down-regulation of the klf5-c-Myc interaction due to klf5 phosphorylation mediates resveratrol repressing the caveolin-1 transcription through the PI3K/PKD1/Akt pathway.

Resveratrol (RSV), a natural polyphenol, has been reported to produce effect on genes transcription in lipid metabolism. In this study, we aim to explore the novel mechanisms of RSV on the regulation of caveolin-1 (Cav-1) transcription. Via body weight, blood glucose, serum lipid, and liver pathology detection, we found that RSV decreased body weight, blood glucose and lipid accumulation in rats fed high-fat diet. Based on co-immunoprecipitation (Co-IP) and western blotting assay, we found that RSV up-regulated klf5 phosphorylation and decreased the interaction of klf5 with c-Myc, which were accompanied by down-regulation of Cav-1 expression in livers of rats fed with high-fat diet. Moreover, in HEK293 cells, we observed RSV enhanced klf5 phosphorylation and separated the interaction of klf5 with c-Myc through inhibiting the activation of PI3K/PKD1/Akt pathway, which maybe promoted c-Myc binding to the promoter to inhibit Cav-1 expression. The results of the present study demonstrated that RSV activated klf5 phosphorylation by inhibiting PI3K/PKD1/Akt pathway, and then attenuated the interaction of klf5 with c-Myc, subsequently probably promoted the c-Myc binding to the promoter to repress Cav-1 expression.

Suppression of Kv1.5 protects against endothelial apoptosis induced by palmitate and in type 2 diabetes mice.

AIMS: Palmitate, a common saturated free fatty acid, induces endothelial apoptosis in vitro in culture endothelial cells and in vivo in type 2 diabetes mellitus (T2DM) patients. The present study aimed to investigate whether Kv1.5 regulates palmitate-induced endothelial apoptosis and endothelial dysfunction in T2DM. MAIN METHODS: In vitro experiments were carried out in primary human HUVECs. Apoptosis was analyzed by flow cytometry. Cell viability was determined by Cell Counting Assay Kit-8. The siRNA transfection was employed to knockdown Kv1.5 protein expression. Intracellular and mitochondrial ROS, and mitochondrial membrane potential were detected using fluorescent probes. Male C57BL/6 mice fed with high-sucrose/fat diet were injected with streptozotocin (35mg/kg body weight) to establish T2DM animal model. KEY FINDINGS: We found that palmitate-induced endothelial apoptosis was parallel to a significant increase in endogenous Kv1.5 protein expression in endothelial cells. Silencing of Kv1.5 with siRNA reduced palmitate-induced endothelial apoptosis, intracellular ROS generation, mitochondrial ROS generation and membrane potential (Δψm) alteration and cleaved caspase-3 protein expression; while increased cell viability and ratio of Bcl-2/Bax. Furthermore, we observed that Kv1.5 protein expression increased in endothelial cells of thoracic aorta of T2DM mice. Silencing of Kv1.5 significantly improved the endothelium-dependent vasodilation in thoracic aortic rings of T2DM mice. SIGNIFICANCE: These results demonstrate that suppression of Kv1.5 protects endothelial cells against palmitate-induced apoptosis via inhibiting mitochondria-mediated excessive ROS generation and apoptotic signaling pathway, suggesting that Kv1.5 may serve as a therapeutic target of treatment for endothelial dysfunction induced by palmitate and lipid metabolism in T2DM patients.

Glucose absorption in nephropathy patients receiving continuous ambulatory peritoneal dialysis.

OBJECTIVES: Peritoneal dialysis patients are at risk of glucose absorption from peritoneal dialysate, not only because of energy imbalance but also the toxic effects of high glucose. The current widely applied formulae may be not suitable for estimation of glucose absorption in continuous ambulatory peritoneal dialysis (CAPD) patients. This study examined the actual glucose absorption in a cohort of CAPD patients and compared the results with estimates from four current formulae. METHODS: We conducted a survey of glucose absorption of a cohort of 72 CAPD patients and compared actual dialysate glucose absorbed and estimates using K/DOQI formula, Grodstein formula, Bodnar formula, or a percentage estimate of 60%. RESULTS: The total dialysate glucose infused each day varied from 54.4 to 191 g/day with average of 102±27.9 g. The average of glucose absorbed was 65.7 g (ranging from 19.5 to 131 g) by actual measurements. The mean absorption rate was 64.4% (ranging from 30.6% to 92.4%). The glucose absorbed from dialysate accounted for 13.8% (ranging from 5.0% to 30.1%) of total energy intake. The average errors of absolute values between actual measurements and estimates were greater than 10 g or 20 g glucose (p<0.001). The average errors in percentages were greater than 20% or 40%, dependently on estimating methods. CONCLUSIONS: The applications of current estimating methods may have limitations. The actual measurement provides dietitians and doctors with more exact information of absorbed glucose and energy compared to the current estimating methods.

Impact of fixed-dose combination of germacrone, curdione, and furanodiene on breast cancer cell proliferation.

OBJECTIVE: Herb combination has been very popular in traditional medical prescriptions such as Traditional Chinese Medicine (TCM). Persistent efforts and attempts have been made to dissect the action mode of TCM in recent years, which has provided certain evidence for inter-herbal interactions. However, the interactions among different components in a single herb have been largely neglected. MATERIALS AND METHODS: In this experimental study, the interactions among different components of a single herb were explored. The effect of three main sesquiterpenes (germacrone, curdione, furanodiene) isolated from Curcuma WenyujinY.H.Chenet C Ling on MDA-MB-231 and MCF-7 breast cancer cell proliferation alone or in combination with a fixed-dose-combination was investigated. RESULTS: Furanodiene significantly inhibited cancer cell proliferation while germacrone and curdione showed no effect. Germacrone enhanced furanodiene's anti-proliferative effect. Curdione showed no effect on furanodiene's anti-proliferative effect but partly reversed the anti-proliferative effect of germacrone and furanodiene combined. The morphological and mitochondrial membrane potential (Δψm) changes showed similar results. However, they demonstrated complicated interactions on the expression of apoptotic-related proteins and key signal transduction proteins. CONCLUSION: Unpredictable and complex interactions among different components in Curcuma WenyujinY.H.Chenet C Ling may exist. The intra-herb interactions should be taken into consideration when attempts are made to interpret the art of TCM formulation or other similar recipes.

In vitro evaluation on the antioxidant capacity of triethylchebulate, an aglycone from Terminalia chebula Retz fruit.

OBJECTIVES: To evaluate the antioxidant and free-radical scavenging activities of triethylchebulate (TCL), an aglycone isolated from the fruit of Terminalia chebula Retz. MATERIALS AND METHODS: Microsomes, mitochondria and red blood cells (RBCs) were isolated from rat liver. The antioxidant capacities were evaluated by determining the inhibitory effects of TCL on lipid peroxidation, hydrogen peroxide (H(2)O(2))-induced RBCs hemolysis and RBCs autoxidative hemolysis. The free-radical scavenging activities were evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) method and 2´,7´-dichlorodihydrofluorescin diacetate (DCFH(2)-DA) assay. RESULT: TCL significantly inhibited FeSO(4)/Cys-induced microsomes lipid peroxidation and protected both H(2)O(2-)-induced RBCs hemolysis and RBCs auto-hemolysis in a dose-dependent manner. Furthermore, TCL demonstrated potent DPPH free-radical scavenging ability with IC(50) at 2.4×10(-5) M. In addition, TCL also moderately suppressed azide-induced mitochondria ROS formation. CONCLUSION: These results demonstrated that TCL was a strong antioxidant and free-radical scavenger, which might contribute to the anti-oxidative ability of Terminalia chebula Retz.