An integrated pathway interaction network for the combination of four effective compounds from ShengMai preparations in the treatment of cardio-cerebral ischemic diseases

Aim:

SMXZF (a combination of ginsenoside Rb1, ginsenoside Rg1, schizandrin and DT-13) derived from Chinese traditional medicine formula ShengMai preparations) is capable of alleviating cerebral ischemia-reperfusion injury in mice. In this study we used network pharmacology approach to explore the mechanisms of SMXZF in the treatment of cardio-cerebral ischemic diseases.

Methods:

Based upon the chemical predictors, such as chemical structure, pharmacological information and systems biology functional data analysis, a target-pathway interaction network was constructed to identify potential pathways and targets of SMXZF in the treatment of cardio-cerebral ischemia. Furthermore, the most related pathways were verified in TNF-α-treated human vascular endothelial EA.hy926 cells and H2O2-treated rat PC12 cells.

Results:

Three signaling pathways including the NF-κB pathway, oxidative stress pathway and cytokine network pathway were demonstrated to be the main signaling pathways. The results from the gene ontology analysis were in accordance with these signaling pathways. The target proteins were found to be associated with other diseases such as vision, renal and metabolic diseases, although they exerted therapeutic actions on cardio-cerebral ischemic diseases. Furthermore, SMXZF not only dose-dependently inhibited the phosphorylation of NF-κB, p50, p65 and IKKα/β in TNF-α-treated EA.hy926 cells, but also regulated the Nrf2/HO-1 pathway in H2O2-treated PC12 cells.

Conclusion:

NF-κB signaling pathway, oxidative stress pathway and cytokine network pathway are mainly responsible for the therapeutic actions of SMXZF against cardio-cerebral ischemic diseases.     

Reduced Nrf2 activation in PI3K phosphorylation‐impaired vitiliginous keratinocytes increases susceptibility to ROS‐generating chemical‐induced apoptosis

Keratinocytes in affected epidermis of vitiligo patients are known to have impaired activation of the PI3K/AKT pathway. Based on critical roles of keratinocytes and oxidative stress in vitiligo development, this study examined whether keratinocytes with impaired PI3K activation were more vulnerable to apoptosis caused by oxidative stress from phenolic compounds, p‐tert‐butylphenol (4‐TBP) and hydroquinone (HQ). Cell viability assay, FACS analysis, ELISA for TNF‐α or IL‐1a, ROS assay, Western blot analysis for Nrf2 expression, and confocal microscopy with anti‐Nrf2 and phospho‐PI3K antibodies were done on primary cultured normal human keratinocytes with or without PI3K knockdown in the presence or absence of chemical treatment or antioxidant. Immunofluorescence staining using anti‐Nrf2, phospho‐PI3K, TNF‐ɑ, and IL‐1ɑ antibodies, ROS assay using dihydroethidium, and TUNEL assay were performed on sets of depigmented and normally pigmented skin from vitiligo patients. Results showed that 4‐TBP or HQ treatment increased apoptosis and the expression levels of TNF‐ɑ, IL‐1ɑ, and ROS in PI3K‐knockdown keratinocytes which reduced Nrf2 nuclear translocation compared to control keratinocytes. These changes were significantly recovered by an antioxidant treatment. Depigmented epidermis of vitiligo patients also showed lower levels of Nrf2 and phospho‐PI3K but higher levels of ROS, TNF‐ɑ, IL‐1ɑ, and ROS with more TUNEL‐positive cells. Therefore, impaired PI3K activation in keratinocytes in depigmented epidermis of vitiligo patients are vulnerable to apoptosis caused by ROS‐generating chemicals due to reduced Nrf2 activation.     

PI3K/Akt/mTOR,a Pathway Less Recognized for Staphylococcal Superantigen-Induced Toxicity

Immunostimulating staphylococcal enterotoxin B (SEB) and related superantigenic toxins cause diseases in humans and laboratory animals by activating cells of the immune system. These toxins bind directly to the major histocompatibility complex (MHC) class II molecules on antigen-presenting cells and specific Vβ regions of T-cell receptors (TCR), resulting in hyperactivation of both T lymphocytes and monocytes/macrophages. Activated host cells produce excessive amounts of proinflammatory cytokines and chemokines, especially tumor necrosis factor α, interleukin 1 (IL-1), IL-2, interferon γ (IFNγ), and macrophage chemoattractant protein 1 causing clinical symptoms of fever, hypotension, and shock. The well-explored signal transduction pathways for SEB-induced toxicity downstream from TCR/MHC ligation and interaction of cell surface co-stimulatory molecules include the mitogen-activated protein kinase cascades and cytokine receptor signaling, culminating in NFκB activation. Independently, IL-2, IFNγ, and chemokines from activated T cells signal via the phosphoinositide 3-kinase (PI3K), the serine/threonine kinases, Akt and mammalian target of rapamycin (mTOR) pathways. This article reviews the signaling molecules induced by superantigens in the activation of PI3K/Akt/mTOR pathways leading to staphylococcal superantigen-induced toxicity and updates potential therapeutics against superantigens.     

The Protective Roles and Molecular Mechanisms of Troxerutin (Vitamin P4) for the Treatment of Chronic Diseases: A Mechanistic Review

Troxerutin (TRX), a semi-synthetic bioflavonoid derived from rutin, has been reported to exert several pharmacological effects including antioxidant, anti-inflammatory, antihyperlipidemic, and nephroprotective. However, the related molecular details and its mechanisms remain poorly understood. In the present review, we presented evidences from the diversity in vitro and in vivo studies on the therapeutic potential of TRX against neurodegenerative, diabetes, cancer and cardiovascular diseases with the purpose to find molecular pathways related to the treatment efficacy. TRX has a beneficial role in many diseases through multiple mechanisms including, increasing antioxidant enzymes and reducing oxidative damage, decreasing in proapoptotic proteins (APAF-1, BAX, caspases-9 and-3) and increasing the antiapoptotic BCL-2, increasing the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and downregulating the nuclear factor κB (NFκ). TRX also reduces acetylcholinesterase activity and upregulates phosphoinositide 3-kinase/Akt signaling pathway in Alzheimer’s disease models. Natural products such as TRX may develop numerous and intracellular pathways at several steps in the treatment of many diseases. Molecular mechanisms of action are revealing novel, possible combinational beneficial approaches to treat multiple pathological conditions.     

Ochratoxin A Induces Oxidative Stress in HepG2 Cells by Impairing the Gene Expression of Antioxidant Enzymes

Ochratoxin A (OTA) is a mycotoxin frequently found in raw and processed foods. While it is considered a possible human carcinogen, the mechanism of action remains unclear. OTA has been shown to be hepatotoxic in both in vitro and in vivo models and oxidative stress may be one of the factors contributing to its toxicity. Hence, the effect of OTA on human hepatocellular carcinoma, HepG2 cells, was investigated on oxidative stress parameters. The cytotoxicity of OTA on HepG2 was time- and dose-dependent within a range between 0.1 and 10 µM; while 100 μM of OTA increased the intracellular reactive oxygen species (ROS) in a time-dependent manner. Additionally, the levels of glutathione (GSH) were increased by 9.7% and 11.3% at 10 and 100 nM of OTA, respectively; while OTA at 100 μM depleted GSH by 40.5% after 24 h exposure compared with the control. Finally, the mRNA level of catalase (CAT) was downregulated by 2.33-, 1.92-, and 1.82-fold after cells were treated with 1, 10, and 10 μM OTA for 24 h, respectively; which was linked to a decrease in CAT enzymatic activity. These results suggest that oxidative stress is involved in OTA-mediated toxicity in HepG2 cells.     

Sodium tanshinone IIA silate inhibits oxygen-glucose deprivation/recovery-induced cardiomyocyte apoptosis via suppression of the NF-κB/TNF-α pathway

Background and Purpose

Inhibition of apoptosis may attenuate the irreversible injury associated with reperfusion. In the current study, we focused on the cytoprotective effects and the underlying mechanism of sodium tanshinone IIA silate (STS) against damage induced by oxygen-glucose deprivation/recovery (OGD/R). in H9c2 cardiomyocytes and the underlying mechanisms.

Experimental Approach

We used a model of cardiac ischaemia/reperfusion, OGD/R in H9c2 cardiomyocytes, to assess the cardioprotective effects of STS. Apoptosis of cells was measured with Hoechst 33342-based fluorescence microscopy, and annexin V-FITC-based flow cytometry. Caspase-3 and caspase-8 activities and mitochondrial membrane potential were also measured using commercial kits. TNF-α in the cell culture supernatant fractions were measured with sandwich elisa, and protein levels assayed using Western blot.

Key Results

STS inhibited OGD/R-induced apoptosis by suppressing JNK-mediated activation of NF-κB, TNF-α expression, activation of caspase-3 and caspase-8 and the Bax/Bcl-2 ratio. Additionally, positive feedback between NF-κB and TNF-α and amplification of TNF-α were inhibited, suggesting that STS plays a protective role against apoptosis in cardiomyocytes, even upon activation of pro-inflammatory cytokines. Interestingly, the cytoprotective effects of STS on OGD/R-induced apoptosis and promotion of cell survival were attenuated after inhibition of PI3K.

Conclusion and Implications

The inhibitory effects of STS on TNF-α and positive feedback signalling of the NF-κB/TNF-α pathways may play important roles in myocardial protection against ischaemia/reperfusion. These protective effects of STS are mediated by suppressing JNK activity through activation of the PI3K-Akt pathway.     

巴戟天丸防治D-半乳糖损伤成骨细胞骨丢失的作用及机制研究

目的 研究巴戟天丸防治D-半乳糖（D-gal）损伤成骨细胞骨丢失的作用及机制。方法 采用新生24 h Wistar大鼠提取的原代成骨细胞,利用D-gal对细胞进行干预,并给予巴戟天丸提取物行药物治疗。分别采用MTT法和碱性磷酸酶试剂盒评价细胞的增殖和分化水平;采用DCFH-DA荧光探针对成骨细胞内活性氧（ROS）水平进行测定。采用Western blotting法对磷酸化蛋白激酶B(p-AKT)、蛋白激酶B(AKT)、血红素氧合酶1(HO-1)、醌NADPH脱氢酶1(NQO1)等氧化相关蛋白的表达进行检测,并采用免疫荧光法测定细胞核因子E2相关因子2(Nrf2)的核内表达水平。结果 巴戟天丸能显著提高D-gal干预细胞的增殖水平和ALP活性,并显著降低细胞内ROS水平。巴戟天丸能够显著促进细胞AKT蛋白的磷酸化,提高HO-1、NQO1的表达水平,进而激活PI3K/AKT信号通路。此外,巴戟天丸提取物还可显著促进成骨细胞核内Nrf2的表达,激活Nrf2信号通路,促进骨形成。结论 本研究首次明确了巴戟天丸可防治D-半乳糖损伤引起的成骨细胞骨丢失,其作用机制可能与调控PI3K/AKT和Nrf...     

Reduction in antioxidant defenses may contribute to ochratoxin A toxicity and carcinogenicity.

Ochratoxin A (OTA) is a renal carcinogen in rodents. Its human health significance is unclear. It likely depends upon the mechanism of carcinogenesis. In a previous microarray study a reduction in nuclear factor-erythroid 2 p45-related factor 2 (Nrf2)-dependent gene expression was observed in the kidney but not in the liver of rats fed OTA up to 12 months. Nrf2 regulates detoxification and antioxidant gene expression. The present report shows that OTA decreased the protein expression of several markers of the Nrf2-regulated gene battery in kidney in vivo indicating that the effects observed at mRNA level may be of biological significance. The OTA-mediated Nrf2 response could be reproduced in an NRK renal cell line and in primary hepatocyte cultures. In in vitro systems, an OTA-mediated inhibition of Nrf2 activity was demonstrated by electrophoretic mobility shift and Antioxidant Regulatory Element-driven luciferase reporter assays. The reduction of Nrf2-regulated gene expression resulted in oxidative DNA damage as evidenced by formation of abasic sites in vitro and confirmed in kidney in vivo. All OTA-mediated effects observed were prevented by pretreatment of cell cultures with inducers of Nrf2 activity. Our data suggest that reduction of cellular defense against oxidative stress by Nrf2 inhibition may be a plausible mechanism of OTA nephrotoxicity and carcinogenicity.     

A Review of the Evidence that Ochratoxin A Is an Nrf2 Inhibitor: Implications for Nephrotoxicity and Renal Carcinogenicity

Several studies have demonstrated that ochratoxin A (OTA) inhibits the nuclear factor, erythroid 2-like 2 (Nrf2) oxidative stress response pathway. At the cellular level this would attenuate (i) glutathione synthesis; (ii) recycling of oxidised glutathione; (iii) activity of oxidoreductases; and (iv) phase II metabolism inducibility. The effects combined would render the cell and tissue more vulnerable to oxidative stress. Indeed, Nrf2 knock out animals exhibit increased susceptibility to various types of chemical-induced injury. Several studies have shown that OTA exposure can inhibit Nrf2 responses. Such an action would initially lead to increased susceptibility to both physiological and chemical-induced cell stress. However, chronic exposure to OTA may also act as a selective pressure for somatic mutations in Nrf2 or its inhibitor Keap-1, leading to constitutive Nrf2 activation. Nrf2 overexpression confers a survival advantage and is often associated with cancer cell survival. Here we review the evidence for OTA’s role as an Nrf2 inhibitor and discuss the implications of this mechanism in nephrotoxicity and carcinogenicity.     

A pharmacological model reveals biased dependency on PI3K isoforms for tumor cell growth

Aim:

To identify the contribution of individual isoform (α, β, γ, δ) of class I PI3Ks to tumor cell growth for proper use of PI3K inhibitors in cancer therapy.

Methods:

A panel of human rhabdomyosarcoma Rh30 cells stably expressing myristoylation (Myr)-tagged one of class I PI3K p110 subunits was established. PI3K activity was analyzed by measuring phosphorylated Akt with Western blotting, and isoform-specific PI3K activities were validated with PI3K isoform-selective inhibitors. The growth of prostate cancer PC-3 cells and B cell type leukemia Raji cells was determined using SRB assay and CCK-8 assay, respectively.

Results:

The phosphorylation of Akt in Rh30-Myr-p110α, β, γ, δ cells was preferentially inhibited by PI3K isoform-selective inhibitors A66 (PI3Kα), TGX221 (PI3Kβ), AS604850 (PI3Kγ) and CAL-101 (PI3Kδ), respectively. A newly obtained PI3K inhibitor WJD008 (10 μmol/L) completely abrogated Akt phosphorylation by all the isoforms of class I PI3Ks, thus acted as a pan-PI3K inhibitor. In prostate cancer PC-3 cells, the PI3K isoform-selective inhibitors were much less potent than WJD008 in suppression of the proliferation. In B cell type leukemia Raji cells, inhibition of PI3Kδ alone or all the isoforms of class I PI3Ks displayed similar potency against the cell proliferation, whereas selective inhibition of individual PI3Kα/β/γ isoforms resulted in negligible activity.

Conclusion:

Rh30-Myr-p110α, β, γ, δ cells are a useful cell model to identify the selectivity of PI3K inhibitors. Pan-PI3K inhibitors are suitable for treating PC-3 cells, whereas selective PI3Kδ inhibitor is sufficient to block Raji cell growth. The biased dependency on PI3K isoforms for tumor cell growth rationalizes the use of PI3K inhibitors with different selectivity for cancer therapy.     

Tripterine prevents endothelial barrier dysfunction by inhibiting endogenous peroxynitrite formation

Background and purpose:

Tripterine is an inhibitor of heat shock protein 90 and an active component of Tripterygium wilfordii Hook F., which is used in traditional Chinese medicine to treat inflammatory diseases such as rheumatoid arthritis. We hypothesized that tripterine inhibits endogenous peroxynitrite formation and thereby prevents endothelial barrier dysfunction.

Experimental approach:

Effects of tripterine were investigated on endothelial barrier function, inducible nitric oxide synthase (iNOS) expression, nicotinamide adenine dinucleotide phasphate (NADPH) oxidase activity, 3-nitrotyrosine formation, protein phosphatase type 2A (PP2A) activity, activation of extracellular-regulated kinase (ERK), c-Jun terminal kinase (JNK) and Janus kinase (Jak2), and degradation of IκB in microvascular endothelial cells exposed to pro-inflammatory stimulus [lipopolysaccharide (LPS) + interferon γ (IFNγ)] and on vascular permeability in air pouches of mice injected with LPS + IFNγ.

Key results:

LPS + IFNγ caused an increase in monolayer permeability, induction of iNOS and NADPH oxidase type 1 (Nox1) proteins, formation of superoxide, nitric oxide and 3-nitrotyrosine, and increase in PP2A activity in endothelial cells. These effects of LPS + IFNγ were diminished by tripterine (50–200 nM). Further, LPS + IFNγ-induced expression of iNOS and Nox1 was attenuated by the mitogen-activated protein kinase kinase 1/2 (MEK1/2) inhibitor PD98059, the JNK inhibitor SP600125, the Jak2 inhibitor AG490 and the NFκB inhibitor MG132, but not by the p38 mitogen-activated protein kinase inhibitor SB203580. LPS + IFNγ stimulated phosphorylation of ERK, JNK and Jak2, and degradation of IκB, but only Jak2 phosphorylation was sensitive to tripterine (50–200 nM). Further, tripterine diminished the increased vascular permeability in inflamed air pouches.

Conclusion and implications:

Our results indicate that, by preventing Jak2-dependent induction of iNOS and Nox1, tripterine inhibits peroxynitrite precursor synthesis, attenuates the increased activity of PP2A and consequently protects endothelial barrier function.     

20C,a new bibenzyl compound,plays a significant role in rotenone-induced oxidative insult

20C,a bibenzyl compound isolated from Gastrodia elata,possesses antioxidative properties in PC12 cells,but its in-depth molecular mechanisms against rotenone-induced neurotoxicity remains unknown.Recent studies indicate that without intact DJ-1,nuclear factor erythroid 2-related factor(Nrf2)protein becomes unstable,and the activity of Nrf2-mediated downstream antioxidant enzymes are thereby suppressed.Therefore,increasing the nuclear translocation of Nrf2 by DJ-1 may present a helpful means for the prevention and treatment of chronic diseases related to oxidative stress.Our results showed that 20C clearly protected PC12 and SH-SY5Y cells against rotenone-induced oxidative injury in a concentration-dependent manner.Furthermore,20C markedly up-regulated the levels of DJ-1,which in turn activated phosphoinositide-3-kinase(PI3K)/Akt signaling and inhibited glycogen synthase kinase 3β(GSK3β)activation,eventually promoting Nrf2 nuclear translocation and inducing the expression of Nrf2-mediated downstream antioxidative enzymes such as HO-1.The antioxidative effects of 20C could be partially blocked by ShR NA-mediated knockdown of DJ-1 and inhibition of the PI3K/Akt pathways with Akt1/2 kinase inhibitor in PC12 and SH-SY5Y cells,respectively.Conclusively,our findings confirm that DJ-1 is necessary for 20C-mediated protection against rotenone-induced oxidative damage,at least in part,by activating PI3K/Akt signaling,and subsequently enhancing the nuclear accumulation of Nrf2.The findings from our investigation suggest that 20C should be developed as a novel candidate for preventing or alleviating the consequences of PD in the future.     

Inhibitory effects of rosiglitazone on paraquat-induced acute lung injury in rats

Aim:

To investigate the effects of the PPAR-γ agonist rosiglitazone on acute lung injury induced by the herbicide paraquat (PQ) and the underlying mechanisms of action.

Methods:

Male Sprague-Dawley rats were injected with PQ (20 mg/kg, ip). Rosiglitazone (3 or 10 mg/kg, ip) was administered 1 h before PQ exposure. Peripheral blood was collected at 4, 8, 24 and 72 h after PQ exposure for measuring the levels of MDA, TNF-α and IL-1β, and the SOD activity. Lung tissues were collected at 72 h after PQ exposure to determine the wet-to-dry (W/D) ratios and lung injury scores, as well as the protein levels of NF-κBp65, PPAR-γ, Nrf2, IκBα and pIκBα.

Results:

At 72 h after PQ exposure, the untreated rats showed a 100% cumulative mortality, whereas no death was observed in rosiglitazone-pretreated rats. Moreover, rosiglitazone pretreatment dose-dependently attenuated PQ-induced lung edema and lung histopathological changes. The pretreatment significantly reduced the levels of TNF-α, IL-1β and MDA, increased SOD activity in the peripheral blood of PQ-treated rats. The pretreatment also efficiently activated PPAR-γ, induced Nrf2 expression and inhibited NF-κB activation in the lung tissues of PQ-treated rats. Furthermore, the pretreatment dose-dependently inhibited IκB-α degradation and phosphorylation, thus inhibiting NF-κB activation.

Conclusion:

Pretreatment with rosiglitazone protects rats against PQ-induced acute lung injury by activating PPAR-γ, inducing Nrf2 expression and inhibiting NF-κB activation.     

L-Carnitine protects against tacrolimus-induced renal injury by attenuating programmed cell death via PI3K/AKT/PTEN signaling

Reducing immunosuppressant-related complications using conventional drugs is an efficient therapeutic strategy.L-carnitine(LC)has been shown to protect against various types of renal injury.In this study,we investigated the renoprotective effects of LC in a rat model of chronic tacrolimus(TAC)nephropathy.SD rats were injected with TAC(1.5 mg·kg^?1·d^?1,sc)for 4 weeks.Renoprotective effects of LC were assessed in terms of renal function,histopathology,oxidative stress,expression of inflammatory and fibrotic cytokines,programmed cell death(pyroptosis,apoptosis,and autophagy),mitochondrial function,and PI3K/AKT/PTEN signaling.Chronic TAC nephropathy was characterized by severe renal dysfunction and typical histological features of chronic nephropathy.At a molecular level,TAC markedly increased the expression of inflammatory and fibrotic cytokines in the kidney,induced oxidative stress,and led to mitochondrial dysfunction and programmed cell death through activation of PI3K/AKT and inhibition of PTEN.Coadministration of LC(200 mg·kg^?1·d^?1,ip)caused a prominent improvement in renal function and ameliorated histological changes of kidneys in TAC-treated rats.Furthermore,LC exerted anti-inflammatory and antioxidant effects,prevented mitochondrial dysfunction,and modulated the expression of a series of apoptosis-and autophagy-controlling genes to promote cell survival.Human kidney proximal tubular epithelial cells(HK-2 cells)were treated with TAC(50μg/mL)in vitro,which induced production of intracellular reactive oxygen species and expression of an array of genes controlling programmed cell death(pyroptosis,apoptosis,and autophagy)through interfering with PI3K/AKT/PTEN signaling.The harmful responses of HK-2 cells to TAC were significantly attenuated by cotreatment with LC and the PI3K inhibitor LY294002(25μM).In conclusion,LC treatment protects against chronic TAC nephropathy through interfering the PI3K/AKT/PTEN signaling.