The critical role of microRNAs in stress response: Therapeutic prospect and limitation.

Stress response refers to the systemic nonspecific response upon exposure to strong stimulation or chronic stress, such as severe trauma, shock, infection, burn, major surgery or improper environment, which disturb organisms and damage their physical and psychological health. However, the pathogenesis of stress induced disorder remains complicated and diverse under different stress exposure. Recently, studies have revealed a specific role of microRNAs (miRNAs) in regulating cellular function under different types of stress, suggesting a significant role in the treatment and prevention of stress-related diseases, such as stress ulcer, posttraumatic stress disorder, stress-induced cardiomyopathy and so on. This paper have reviewed the literature on microRNA related stress diseases in different databases including PubMed, Web of Science, and the MiRbase. It considers only peer-reviewed papers published in English between 2004 and 2018. This review summarizes new advances in principles and mechanisms of miRNAs regulating stress signalling pathway and the role of miRNAs in human stress diseases. This comprehensive review is to provide an integrated account of how different stresses affect miRNAs and how stress-miRNA pathways may, in turn, be linked with disease, which offers some potential strategies for stress disorder treatment. Furthermore, the limitation of current studies and challenges for clinical use are discussed.

Economic evaluation of nivolumab as a second-line treatment for advanced renal cell carcinoma from US and Chinese perspectives.

BACKGROUND: Nivolumab is a new standard of care for patients with metastatic renal cell carcinoma (mRCC) and provides an overall survival benefit of 5.40 months in comparison with everolimus. This study evaluated the cost-effectiveness of nivolumab for the second-line treatment of mRCC from the perspective of US payers and identified the range of drug costs for which the addition of nivolumab to standard therapy could be considered cost-effective from a Chinese perspective. METHODS: A partitioned survival model was constructed to estimate lifetime costs, life-years, and quality-adjusted life-years (QALYs). Costs were estimated for the US and Chinese health care systems. One-way and probabilistic sensitivity analyses were performed. RESULTS: Nivolumab provided an additional 0.29 QALYs at a cost of $151,676/QALY in the United States. The probabilistic sensitivity analysis showed that at a willingness-to-pay threshold of $100,000/QALY, at the current cost of nivolumab, the chance of nivolumab being cost-effective was 3.10%. For China, when nivolumab cost less than $7.90 or $9.70/mg, there was a nearly 90% likelihood that the incremental cost-effectiveness ratio for nivolumab would be less than $22,785 or $48,838/QALY, respectively. CONCLUSIONS: For the United States, nivolumab is unlikely to be a high-value treatment for mRCC at the current price, and a price reduction appears to be justified. In China, value-based prices for nivolumab are $7.90 and $9.70/mg for the country and Beijing City, respectively. This study could and should inform the multilateral drug-price negotiations in China that may be upcoming for nivolumab. Cancer 2017;123:2634-41. © 2017 American Cancer Society.

Calcitonin gene-related peptide down-regulates bleomycin-induced pulmonary fibrosis.

We have found that eIF3a plays an important role in bleomycin-induced pulmonary fibrosis, and up-regulation of eIF3a induced by TGF-ß1 is mediated via the ERK1/2 pathway. Whether ERK1/2 - eIF3a signal pathway is involved in calcitonin gene-related peptide (CGRP)-mediated pathogenesis of bleomycin-induced pulmonary fibrosis remains unknown. Pulmonary fibrosis was induced by intratracheal instillation of bleomycin (5 mg/kg) in rats. Primary pulmonary fibroblasts were cultured to investigate the proliferation by BrdU incorporation method and flow cytometry. Sensory CGRP depletion by capsaicin exacerbated bleomycin-induced pulmonary fibrosis in rats, as shown by a significant disturbed alveolar structure, marked thickening of the interalveolar septa and dense interstitial infiltration by inflammatory cells and fibroblasts, accompanied with increased expression of TGF-ß1, eIF3a, phosphorylated ERK1/2, α-SMA, collagen I, and collagen III. Exogenous application of CGRP significantly inhibited TGF-ß1-induced proliferation and differentiation of pulmonary fibroblasts concomitantly with decreased expression of eIF3a, phosphorylated ERK1/2, α-SMA, collagen I, and collagen III. These effects of CGRP were abolished in the presence of CGRP8-37. These results suggest that endogenous CGRP is related to the development of pulmonary fibrosis induced by bleomycin, and the inhibitory effect of CGRP on proliferation of lung fibroblasts involves the ERK1/2 - eIF3a signaling pathway.

Accelerated onset of senescence of endothelial progenitor cells in patients with type 2 diabetes mellitus: role of dimethylarginine dimethylaminohydrolase 2 and asymmetric dimethylarginine.

The risk of cardiovascular complications in diabetic patients is mainly associated with endothelial dysfunction. Reduced number of EPCs and impaired function of EPCs in diabetes result in imbalance of endothelial homeostasis and dysfunction of vessels. In patients with diabetes mellitus, plasma levels of asymmetric dimethylarginine (ADMA) were elevated, while the expression and activity of dimethylarginine dimethylaminohydrolase (DDAH) were reduced. In the present study, we investigated the role of the DDAH2/ADMA pathway in the senescence of EPCs in type 2 diabetic patients and cultured EPCs treated with high glucose. The results showed that the percentage of senescent EPCs increased while the expression of DDAH2 decreased concomitantly with an increase in the plasma levels of ADMA in patients with type 2 diabetes mellitus (T2DM). Similar results were seen in cultured EPCs treated with high glucose. Exogenous application of ADMA accelerated the senescence of EPCs in a dose-dependent manner, and overexpression of DDAH2 inhibited high glucose-induced EPCs senescence. In addition, it has also been reported that DDAH/ADMA pathway is regulated by silent information regulator 1 (SIRT1) in endothelial cell. In the present study, we found decreased expression of SIRT1 both in T2DM patients and EPCs pretreated with high glucose. And resveratrol (activating SIRT1) inhibited high glucose-induced EPCs senescence by upregulating the expression of DDAH2 and decreasing the levels of ADMA. Taken together, we concluded that DDAH2/ADMA is involved in the accelerated senescence of EPCs in diabetes, which is associated with the activation of SIRT1.

Nuclear cardiac myosin light chain 2 modulates NADPH oxidase 2 expression in myocardium: a novel function beyond muscle contraction.

Recent studies demonstrated that NADPH oxidase 2 (NOX2) expression in myocardium after ischemia-reperfusion (IR) is significantly upregulated. However, the underlying mechanisms remain unknown. This study aims to determine if nuclear cardiac myosin light chain 2 (MYL2), a well-known regulatory subunit of myosin, functions as a transcription factor to promote NOX2 expression following myocardial IR in a phosphorylation-dependent manner. We examined the phosphorylation status of nuclear MYL2 (p-MYL2) in a rat model of myocardial IR (left main coronary artery subjected to 1 h ligation and 3 h reperfusion) injury, which showed IR injury and upregulated NOX2 expression as expected, accompanied by elevated H2O2 and nuclear p-MYL2 levels; these effects were attenuated by inhibition of myosin light chain kinase (MLCK). Next, we explored the functional relationship of nuclear p-MYL2 with NOX2 expression in H9c2 cell model of hypoxia-reoxygenation (HR) injury. In agreement with our in vivo findings, HR treatment increased apoptosis, NOX2 expression, nuclear p-MYL2 and H2O2 levels, and the increases were ameliorated by inhibition of MLCK or knockdown of MYL2. Finally, molecular biology techniques including co-immunoprecipitation (Co-IP), chromatin immunoprecipitation (ChIP), DNA pull-down and luciferase reporter gene assay were utilized to decipher the molecular mechanisms. We found that nuclear p-MYL2 binds to the consensus sequence AGCTCC in NOX2 gene promoter, interacts with RNA polymerase II and transcription factor IIB to form a transcription preinitiation complex, and thus activates NOX2 gene transcription. Our results demonstrate that nuclear MYL2 plays an important role in IR injury by transcriptionally upregulating NOX2 expression to enhance oxidative stress in a phosphorylation-dependent manner.

Involvement of glutamate-cystine/glutamate transporter system in aspirin-induced acute gastric mucosa injury.

Large-dose or long-term use of aspirin tends to cause gastric mucosa injury, which is recognized as the major side effect of aspirin. It has been demonstrated that glutamate exerts a protective effect on stomach, and the level of glutamate is critically controlled by cystine/glutamate transporter (Xc(-)). In the present study, we investigated the role of glutamate-cystine/glutamate transporter system in aspirin-induced acute gastric mucosa injury in vitro and in vivo. Results showed that in human gastric epithelial cells, aspirin incubation increased the activity of LDH and the number of apoptotic cells, meanwhile down-regulated the mRNA expression of Xc(-) accompanied with decreased glutamate release. Similar results were seen in a rat model. In addition, exogenous l-glutamate attenuated the gastric mucosa injury and cell damage induced by aspirin both in vitro and in vivo. Taken together, our results demonstrated that acute gastric mucosa injury induced by aspirin is related to reduction of glutamate-cystine/glutamate transporter system activity.

Regulation of endothelial progenitor cell differentiation and function by dimethylarginine dimethylaminohydrolase 2 in an asymmetric dimethylarginine-independent manner.

Endothelial progenitor cells (EPCs) are involved in the repair of vessels and angiogenesis and are useful in the treatment of ischemic diseases. The dimethylarginine dimethylaminohydrolase (DDAH)/asymmetric dimethylarginine (ADMA) pathway is regulated by silent information regulator 1 (SIRT1), leading to the senescence of endothelial cells (ECs). Here, we demonstrated that peripheral blood EPCs predominantly expressed DDAH2 that increased with EPC differentiation. EPC senescence and dysfunction were induced on interruption of DDAH2 expression, whereas the mRNA expression of vascular endothelial growth factor (VEGF) and kinase-domain insert containing receptor (KDR) were downregulated. Moreover, SIRT1 expression increased with EPC differentiation. Interruption of SIRT1 inhibited DDAH2, VEGF, and KDR expression, but had no effect on the level of ADMA. From our data, we concluded that DDAH2 is involved in the differentiation of EPCs and regulates the senescence and function of EPCs through the VEGF/KDR pathway by activation of SIRT1.

Involvement of anandamide transporter in calcitonin gene-related peptide expression stimulated by nitroglycerin and influence of ALDH2 Glu504Lys polymorphism.

The aim of this study was to investigate whether N-arachidonic acid ethanolamine (anandamide, AEA) transporter contributed to calcitonin gene-related peptide (CGRP) expression mediated by nitroglycerin (GTN) in peripheral blood mononuclear cells (PBMCs) of healthy volunteers and its association with the mitochondrial aldehyde dehydrogenase-2 (ALDH2) Glu504Lys (ALDH2*2) polymorphism. In 10 ALDH2*2-genotyped Chinese volunteers, we assessed the activity of AEA transporter and expression of CGRP messenger ribonucleic acid (mRNA) in cultured PBMCs treated with different concentration of GTN with or without pretreatment with AM404 (the AEA transporter blocker). In this study, the activity of AEA transporter and expression of CGRP mRNA elevated with the increase in the concentration of GTN. Pretreatment of the cells with AM404 (1 µM) 2 hours before GTN reduced the GTN-induced increase in both AEA transporter activity and CGRP mRNA expression significantly, and cells with the ALDH2*1/*1 homozygote genotype showed significantly higher activity of AEA transporter and CGRP mRNA expression than carriers of the ALDH2*2 allele. Therefore, we strongly suggested that GTN can stimulate CGRP expression by elevating the AEA transporter activity, which is affected by ALDH2 Glu504Lys polymorphism.

Fluorofenidone attenuates vascular remodeling in hypoxia-induced pulmonary hypertension of rats.

Fluorofenidone (AKF-PD) is a novel pyridone derivate that targets transforming growth factor-ß1 (TGF-ß1) signaling. Previous studies have proven that AKF-PD functions as an antifibrotic agent in pulmonary fibrosis and renal fibrosis models. Activated TGF-ß1 signaling is thought to be a major feature of pulmonary hypertension (PH). TGF-ß1 exerts powerful pro-proliferation effects on pulmonary arterial smooth muscle cells (PASMCs), and hence, prompts vascular remodeling. This study is designed to investigate the effect of AKF-PD on vascular remodeling in a rat model of hypoxia-induced PH. PH was induced in rats by 4 weeks of hypoxia. The expression of TGF-ß1, collagen I, and collagen III was analyzed by ELISA, immunohistochemistry, real-time PCR, or Western blot. Proliferation of cultured PASMCs was determined by the BrdU incorporation method and flow cytometry. The results showed that AKF-PD treatment (0.5 or 1.0 g·(kg body mass)·d(-1)) for 4 weeks attenuated pulmonary vascular remodeling and improved homodynamic parameters. TGF-ß1 level was significantly down-regulated by AKF-PD both in vivo and in vitro. Furthermore, hypoxia- and TGF-ß1-induced PASMC proliferation and collagen expression were both significantly suppressed by AKF-PD. These results suggest that AKF-PD ameliorates the progression of PH induced by hypoxia in rats through its regulation of TGF-ß1 expression, PASMC proliferation, and the extracellular matrix.

Dimethylarginine dimethylaminohydrolase 1 regulates nerve growth factor-promoted differentiation of PC12 cells in a nitric oxide-dependent but asymmetric dimethylargenine-independent manner.

There are significant morphological and biochemical alterations during nerve growth factor (NGF)-promoted neuronal differentiation, and the process is regulated by molecules, including nitric oxide (NO). Dimethylarginine dimethylaminohydrolase (DDAH) is thought to play a critical role in regulating NO production via hydrolyzing the endogenous NO synthase (NOS) inhibitor asymmetric dimethylarginine (ADMA). Thus, we tested the role of DDAH in NGF-promoted differentiation of PC12 (pheochromocytoma) cells. The present results show that both mRNA and protein levels of DDAH1 were increased, whereas those of DDAH2 were decreased, during NGF-promoted cell differentiation. Both the DDAH activity and the ADMA level in cultured medium were unchanged in this process. NGF promoted neurite formation and induced the expression of microtubule-associated protein 2 (MAP2), a neuronal marker, which were both significantly repressed by DDAH1 silence with small interfering RNA but not by DDAH2 silence. The expressions of three isoforms of NOS were markedly upregulated after NGF stimulation with a time course similar to that of DDAH1, which were attenuated by DDAH1 silence. Conversely, overexpression of DDAH1 accelerated neurite formation in PC12 cells, concomitantly with upregulating the expression of three NOS isoforms. In summary, our data reveal the critical regulatory effect of DDAH1 on NGF-promoted differentiation of PC12 cells in an NOS/NO-dependent but ADMA-independent manner.

A novel pathway of NADPH oxidase/vascular peroxidase 1 in mediating oxidative injury following ischemia-reperfusion.

Vascular peroxidase 1 (VPO1) can utilize reactive oxygen species (ROS) generated from NADPH oxidase (NOX) to catalyze peroxidative reactions. This study was performed to identify a novel pathway of NOX/VPO1 in mediating the oxidative injury following myocardial ischemia reperfusion (IR). In a rat model of myocardial IR, the infarct size, serum creatine kinase (CK) activity, apoptosis, NOX activity, NOX2 and VPO1 expression were measured. In a cell (rat heart-derived H9c2 cells) model of hypoxia/reoxygenation (HR), the apoptosis, NOX activity, NOX2 and VPO1 expression, and H(2)O(2) and HOCl levels were examined. In vivo, IR caused 54.8 ± 1.7 % infarct size in myocardium accompanied by elevated activities of CK, caspase-3 and NOX, up-regulated VPO1 expression and high numbers of myocardial apoptotic cells; these effects were attenuated by pretreatment with the inhibitor of NOX. In vitro, inhibition of NOX or silencing of NOX2 or VPO1 expression significantly suppressed HR-induced cellular apoptosis concomitantly with decreased HOCl production. Inhibition of NOX or silencing of NOX2 led to a decrease in H(2)O(2) production accompanied by a decrease in VPO1 expression and HOCl production. However, silencing of VPO1 expression did not affect NOX2 expression and H(2)O(2) production. H(2)O(2)-induced VPO1 expression was partially reversed by JNK or p38 MAPK inhibitor. Our results demonstrate a novel pathway of NOX2/VPO1 in myocardium, where VPO1 coordinates with NOX2 and amplifies the role of NOX-derived ROS in oxidative injury following IR.

Influence of ALDH2 Glu504Lys polymorphism on nitroglycerin response in chronic heart failure and involvement of Calcitonin Gene Related Peptide (CGRP).

OBJECTIVE: The aim of this study was to investigate whether the neuropeptide calcitonin gene related peptide (CGRP) contributes to nitroglycerin (GTN) response in patients with chronic heart failure (CHF) and the association with the mitochondrial aldehyde dehydrogenase-2 (ALDH2) Glu504Lys (ALDH2*2) polymorphism. METHODS: This is a 2-period, placebo-controlled clinical study. An intravenous infusion of saline followed by GTN (20 µg/min), each for 2 hours, respectively, was given to 49 stable CHF patients. Blood pressure (BP), heart rate (HR) and respiratory rate (RR) were measured at baseline, at 10 min, 30 min, 1.0 h, 1.5 h, and 2.0 h after initiation of saline infusion and initiation of GTN therapy. Blood samples were drawn for the determination of plasma CGRP for 49 patients at baseline, and at 2.0 h after initiation of saline and GTN infusion, respectively. Global clinical status of the patients was evaluated. Left ventricular ejection (LVEF), left ventricular end-diastolic volume (LVEDV), stroke volume (SV) and cardiac output (CO) were measured with 2D echocardiography with Simpson's biplane method (Pillip HP sonos 5500) by the same investigator at baseline and at 2.0 h after initiation of saline and GTN infusion. RESULTS: Systolic blood pressure (SBP), diastolic blood pressure (DBP), and left ventricular end-diastolic volume (LVEDV) were decreased, while left ventricular ejection fraction (LVEF) was increased at the end of GTN infusion (p < 0.001, respectively). Saline infusion showed no hemodynamic effects. At the end of GTN infusion, ALDH2*1/*1 homozygous patients showed higher degrees of both the absolute decrease in SBP (DSBP) (p < 0.001) and increase in LVEF (p < 0.001) than carriers of the ALDH2*2 allele. Mean plasma concentration of CGRP was increased after GTN infusion (p < 0.001), but not changed after saline infusion (p > 0.05). Changes in plasma concentration of CGRP correlated positively with the improvement in LVEF (r = 0.400, p = 0.004), while correlated negatively with changes in SBP (r = -0.300, p = 0.036) and LVEDV (r = -0.290, p = 0.043). CONCLUSIONS: ALDH2*2 polymorphism is associated with contributions of CGRP to GTN response in CHF patients.

Involvement of microRNA/cystine/glutamate transporter in cold-stressed gastric mucosa injury.

Stress ulcers are complicated by severe trauma and other critical diseases, the mechanism of which remains unclear. An increasing number of studies have shown that microRNAs (miRNAs) are important regulators of stress responses such as hypoxia, abnormal temperature, and inflammation. The evidence indicates that miRNAs are also involved in regulating stress-induced ulcers. Recently, we demonstrated that gastric mucosal injury induced by aspirin is related to the reduction of glutamate levels by inhibition of cystine/glutamate transporter (xCT) activity. In the present study, the effect of a miRNA/xCT on gastric mucosal injury induced by cold stimulation was investigated. We found that cold stimulation induced gastric mucosa injury with a reduction in glutamate levels and xCT activity and upregulation of miR-143, miR-152, and miR-181 expression. Exogenous glutamate significantly alleviated gastric mucosa injury by cold stimulation. In vitro experiments demonstrated that treatment with miR-143, miR-152, or miR-181 mimics directly induced cell damage. The effects of these mimics were alleviated by exogenous glutamate. The present study suggests that miR-143, miR-152, and miR-181 are involved in cold stimulation-induced acute gastric mucosal injury. Furthermore, the regulatory effect of miRNAs on gastric mucosa injury induced by cold stimulation is related to a decrease in glutamate release by reduction of cystine/glutamate transporter activity.

Decreased xCT activity in patients associated with Helicobacter pylori infection.

Objective: In animals, Helicobacter pylori (Hp)-induced gastric injury is accompanied by a decrease in the activity of the cysteine/glutamate transporter (xCT), which regulates extracellular glutamate levels. However, the impact of xCT activity in patients with Hp infection remains unclear. This study aims to investigate variations of xCT activity in the gastric mucosa of patients with Hp infection and to provide a clinical basis for identifying targets related to Hp infection. Methods: Our study included a total of 67 patients with gastritis, which consisted of 44 Hp-negative and 23 Hp-positive peptic ulcer cases. The inclusion criteria used to select patients were as follows: gastric histology was determined with a gastroscope, antral biopsies were taken for urease tests, and pathology and culture were performed for analysis of Hp-colonization. The clinical characteristics of the patients were obtained, the expressions of microRNAs and xCT protein were detected using immune histochemical analysis, and the concentration of glutamate in their gastric secretion was determined. Results: The findings revealed that xCT expression was significantly lower in Hp-positive patients as compared to Hp-negative individuals, which was accompanied by a decrease in glutamate concentration in gastric juice. We also discovered a high expression of microRNAs that have been shown to negatively regulate xCT expression, in Hp-positive patients. Conclusion: Reduced xCT activity in patients may play an important role in gastric ulcers caused by Hp infection. Our findings suggest that the microRNA/xCT pathway could be a potential treatment target for Hp-infection-related ulcers.

Effect of profilin-1 on the asymmetric dimethylarginine-induced vascular lesion-associated hypertension.

Previous studies have demonstrated that the levels of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthesis, are strongly associated with hypertension, diabetes, and cardiovascular diseases. Profilin-1, an actin-binding protein, has been documented to be involved in endothelial injury and in the proliferation of vascular smooth muscle cells resulting from hypertension. However, the role of profilin-1 in ADMA-induced vascular injury in hypertension remains largely unknown. Forty healthy subjects and forty-two matched patients with essential hypertension were enrolled, and the related indexes of vascular injury in plasma were detected. Rat aortic smooth muscle cells (RASMCs) were treated with different concentrations of ADMA for different periods of time and transfected with profilin-1 small hairpin RNA to interrupt the expression of profilin-1. To determine the role of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway, RASMCs were pretreated with AG490 or rapamycin. The expression of profilin-1 was tested using real-time polymerase chain reaction (PCR) and western blot analysis. Cell proliferation was measured by flow cytometry and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazoliumbromide assays. Compared with healthy subjects, the levels of ADMA and profilin-1 were markedly elevated in hypertensive individuals, while the levels of NO were significantly decreased (p < 0.05). In vitro, studies showed ADMA-induced profilin-1 expression in a concentration- and time-dependent manner in RASMCs (p < 0.05), concomitantly with promoting the proliferation of RASMCs. Furthermore, ADMA-mediated proliferation of RASMCs and upregulation expression of profilin-1 were inhibited by blockade of the JAK2/STAT3 pathway or knockdown of profilin-1. Profilin-1 implicated in the ADMA-mediated vascular lesions in hypertension.

Association of GSTM1 null polymorphism with isosorbide-5-mononitrate cardiovascular response and involvement of CGRP in healthy Chinese male volunteers.

OBJECTIVES: To determine whether functional polymorphisms of glutathione S-transferase µ type 1 (GSTM1) and aldehyde dehydrogenase-2 (ALDH2) affect the isosorbide 5-mononitrate (IS-5-MN) response, and the role of the calcitonin gene-related peptide (CGRP) in IS-5-MN response in healthy volunteers. METHODS: A two-phase, placebo-controlled study was carried out in 24 healthy Chinese volunteers with their ALDH2 and GSTM1 genotypes known. During each phase, either 20-mg IS-5-MN tablet or placebo was orally administered; blood pressure (BP), heart rate, and plasma concentration of CGRP was determined before and at several time points after drug administration. Pharmacokinetic parameters of IS-5-MN were determined. RESULTS: GSTM1 null individuals showed significantly lower systolic BP (SBP) and diastolic BP (DBP), and higher degree of decreases in SBP (ΔSBP) and DBP (ΔDBP) after IS-5-MN administration. GSTM1 null individuals showed significantly decreased IS-5-MN area under the plasma concentration-time curve than GSTM1 wild-type individuals (P<0.05). Plasma concentration of CGRP was increased significantly at 0.5 (P<0.01), 1 (P<0.05), and 2 h (P<0.05) after IS-5-MN administration in GSTM1 null individuals but not wild-type individuals. GSTM1 null individuals also showed significantly higher degree of percentage increase in the plasma concentration of CGRP than GSTM1 wild-type individuals at 1 h after IS-5-MN administration (P<0.05). IS-5-MN upregulated CGRP I and CGRP II mRNA expressions in cultured peripheral blood mononuclear cells, and the IS-5-MN-induced CGRP II mRNA expression was inhibited by GSTs inhibitor, ethacrynic acid. No difference in the IS-5-MN response was observed between ALDH2 genotypes. CONCLUSION: We suggest that GSTM1, but not ALDH2, may interfere with the bioactivation of IS-5-MN, and CGRP contributes to the IS-5-MN response in a GSTM1 genotype-dependent manner.

Furoxan nitric oxide donor coupled chrysin derivatives: synthesis and vasculoprotection.

A series of furoxan-based nitric oxide-releasing chrysin derivatives were synthesized. Pharmacological assays indicated that all chrysin derivatives exhibited in vitro inhibitory activities against aldose reductase and advanced glycation end-product formation. Some chrysin derivatives were also found to increase the glucose consumption of HepG2 cells. Furthermore, the compounds released a low amount of NO in the presence of L-cysteine (range from 0.20% to 1.89%). These hybrid furoxan-based NO donor chrysin derivatives offer a mutual prodrug design concept for the development of therapeutic or preventive agents for vascular complications due to diabetes.

Rutaecarpine prevents hypoxia-reoxygenation-induced myocardial cell apoptosis via inhibition of NADPH oxidases.

It is proposed that myocardial cell apoptosis causes ventricular remodeling and heart failure. The aim of the present study was to determine the effects of rutaecarpine (Rut) on hypoxia-reoxygenation (H-R)-induced apoptosis in myocardial cell line H9c2, as well as the underlying mechanisms. Cultured H9c2 cells were exposed to hypoxia for 24 h, followed by 12 h reoxygenation. Rut (in concentrations of 0.1, 1, and 10 µmol/L) was added 1 h prior to H-R. Cell viability and lactate dehydrogenase were measured to evaluate the cell injuries. Apoptosis was evaluated by Hoechst 33258 staining and flow cytometry. NADPH oxidase activity was measured by assay kit; intracellular reactive oxygen species (ROS) generation was detected by 2',7'-dichlorofluorescein diacetate; and Nox2, Nox4, and p47(phox) mRNA and protein expression were analyzed by real-time PCR and Western blotting, respectively. The results showed that H-R significantly decreased cell viability and increased the lactate dehydrogenase release, as well as the apoptotic rate, concomitantly with enhanced NADPH oxidase activity. H-R also upregulated mRNA and protein expressions of Nox2, Nox4, and p47(phox) and increased ROS production. Treatment with Rut markedly reversed these effects introduced by H-R. These results suggest that the protective effects of Rut against H-R-induced myocardial cell injury and apoptosis might, at least partly, be due to the inhibition of the NADPH oxidase - ROS pathway.

Effect of resveratrol derivative BTM-0512 on high glucose-induced dysfunction of endothelial cells: role of SIRT1.

Hyperglycemia impairs the function of endothelial cells. Sirtuin 1 (SIRT1) is involved in regulating the function of endothelial cells. Resveratrol, a polyphenol found in many plant species, exerts protective effects on endothelial cells through activation of SIRT1. The aims of this work were to explore whether BTM-0512, a novel derivative of resveratrol, is able to exert beneficial effects on high glucose-induced dysfunction of endothelial cells through regulation of SIRT1. We found that high glucose significantly impaired the function of endothelial cells as shown by reduced tube formation, cell migration, and cell adhesion concomitantly with downregulation of mRNA expression of SIRT1 and vascular endothelial growth factor as well as increased tumor necrosis factor-α release and reactive oxygen species production. These effects of high glucose were inhibited by pretreatment with BTM-0512. The beneficial effects of BTM-0512 on high glucose-induced cell dysfunction were abolished by splitomicin, a specific inhibitor of SIRT1. The regulatory effects of BTM-0512 on high glucose-induced changes in vascular endothelial growth factor mRNA expression and tumor necrosis factor-α release were also abolished by splitomicin. The results suggest that BTM-0512 exerts beneficial effects on high glucose-induced endothelial cell dysfunction through regulation of the SIRT1 - reactive oxygen species - vascular endothelial growth factor - tumor necrosis factor-α pathway.

Protective effect of phloroglucinol against myocardial ischaemia-reperfusion injury is related to inhibition of myeloperoxidase activity and inflammatory cell infiltration.

1. It has been shown that phloroglucinol has anti-inflammatory and anti-oxidant properties. Both inflammatory cell infiltration and myeloperoxidase (MPO) activation play an important role in myocardial reperfusion injury. The aim of the present study was to explore the effect of phloroglucinol on myocardial reperfusion injury and the mechanisms involved. 2. Anaesthetized rats were pretreated with phloroglucinol (15 or 30 mg/kg, i.g.) or vehicle (5 mmol/L carboxymethyl cellulose sodium) 30 min prior to experimentation. The left main coronary artery was subjected to 1 h occlusion followed by 3 h reperfusion. Infarct size, the release of creatine kinase (CK), inflammatory cell infiltration, MPO activity and protein content, catalase in the blood and myocardium, and myocardial apoptosis were measured. 3. Following myocardial ischaemia and reperfusion in vehicle-treated rats, infarct size was 43.5 ± 3.7% (relative to the area at risk). Accompanying detrimental changes included elevated CK, enhanced inflammatory cell infiltration, high numbers of myocardial apoptotic cells, elevated caspase 3 activity, increased MPO activity and content in the plasma and myocardium and reduced catalase activity. These effects were attenuated by pretreatment with both doses of phloroglucinol (15 and 30 mg/kg, i.g.). 4. The results of the present study suggest that phloroglucinol protects the myocardium against ischaemia-reperfusion injury in rats and that its beneficial effects are related to inhibition of MPO activity and inflammatory cell infiltration.