Zhi-Chun Yang

Expression of apoptosis-associated microRNAs in ethanol-induced acute gastric mucosal injury via JNK pathway

MicroRNAs (miRNAs) have been shown to be closely associated with cellular apoptosis, but their involvement in response to ethanol-induced gastric mucosal epithelial cell apoptosis remains largely unknown. The purpose of this study was to investigate the expression profile of apoptosis-associated miRNAs in ethanol-induced acute gastric mucosal injury and the mechanisms underlying injury. Gastric mucosal injury was induced in rats by oral administration of ethanol, and gastric tissues were collected for analysis of gastric ulcer index, apoptosis ratio, caspase-3 activity, and miRNAs expression. Cell cultures of human gastric mucosal epithelial cells (GES-1) were incubated with ethanol to induce apoptosis. Mimics or inhibitors of miRNAs or c-Jun N-terminal kinase (JNK) inhibitor were added to the cell culture medium. GES-1 cells were collected for analysis of apoptosis ratio, caspase-3 activity, miRNAs expression, and protein phosphorylation levels of JNK, p38 mitogen-activated protein kinase (p38MAPK), or extracellular signal-regulated kinase (ERK). In the animal experiments, gastric ulcer index, cellular apoptosis, and caspase-3 activity were significantly increased, accompanied by up-regulation of miR-145 and down-regulation of the microRNAs miR-17, miR-19a, miR-21, miR-181a, and miR-200c. In the human cell culture experiments, the anti-apoptotic effects of miR-19a and miR-21 or pro-apoptotic effect of miR-145 were confirmed by their corresponding mimics or inhibitor; the ethanol-induced GES-1 apoptosis as well as the changes in miRNAs expression were significantly attenuated in the presence of JNK inhibitor. These results demonstrated that miR-145, miR-19a, and miR-21 were the apoptosis-associated miRNAs in gastric mucosal epithelial cells. The regulation of expression of these 3 miRNAs in ethanol-induced GES-1 apoptosis involved the JNK pathway.

Stimulation of Calcitonin Gene-Related Peptide Release Through Targeting Capsaicin Receptor: A Potential Strategy for Gastric Mucosal Protection

Calcitonin gene-related peptide (CGRP) is a predominant neurotransmitter from capsaicin-sensitive sensory nerves, which are widely distributed in the gastrointestinal system. These sensory nerves are reported to be involved in the protection of gastric mucosa against damage by various stimuli, and CGRP is a potential mediator in this process. In addition to increase in gastric mucosal blood flow, the beneficial effects of CGRP on gastric mucosa include inhibition of gastric acid secretion, prevention of cellular apoptosis and oxidative injury. The synthesis and release of CGRP is regulated by the capsaicin receptor which is known as transient receptor potential vanilloid subfamily member 1 (TRPV1) and the agonists of TRPV1 have the potential for gastric mucosal protection. So far, multiple TRPV1 agonists, including capsaicin, capsiate, anandamide and rutaecarpine are reported to exert beneficial effects on gastric mucosal injury induced by various stimuli. Therefore, the TRPV1/CGRP pathway represents a novel target for therapeutic intervention in human gastric mucosal injury.

Vanillyl nonanoate protects rat gastric mucosa from ethanol-induced injury through a mechanism involving calcitonin gene-related peptide

Previous studies have demonstrated that capsaicin-sensitive sensory nerves are involved in the protection of gastric mucosa against damage by various stimuli and calcitoin gene-related peptide (CGRP) is a potential mediator in this process. This study was performed to explore the effect of vanillyl nonanoate, a capsaicin analog, on ethanol-induced gastric mucosal injury and the possible underlying mechanisms. A rat model of gastric mucosal injury was induced by oral administration of acidified ethanol and gastric tissues were collected for analysis of gastric ulcer index, cellular apoptosis, the activities of caspase-3, catalase and superoxide dismutase (SOD), levels of CGRP, TNF-α and malondialdehyde (MDA). The results showed that acute administration of ethanol significantly increased gastric ulcer index concomitantly with increased cellular apoptosis, caspase-3 activity, TNF-α and MDA levels as well as decreased activities of catalase and SOD. Pretreatment with 1mg/kg vanillyl nonanoate significantly attenuated ethanol-induced gastric mucosal injury and cellular apoptosis accompanied by increase of CGRP expression, and SOD activity and decrease of caspase-3 activity, TNF-α and MDA levels. The effects of vanillyl nonanoate were inhibited by capsazepine, an antagonist of capsaicin receptor. Our results suggested that vanillyl nonanoate was able to protect the gastric mucosa against ethanol-induced gastric mucosal injury. The underlying mechanism is related to stimulation of CGRP release and subsequent suppression of ethanol-induced inflammatory reaction, cellular apoptosis and oxidative stress.

Beneficial effects of capsiate on ethanol-induced mucosal injury in rats are related to stimulation of calcitonin gene-related Peptide release.

Capsiate is a non-pungent analogue of capsaicin from CH-19 Sweet peppers. Capsaicin is reported to trigger calcitonin gene-related peptide (CGRP) release through activation of transient receptor potential vanilloid subfamily member 1 (TRPV1) and produces beneficial effects on gastric mucosa. This study aimed to investigate whether capsiate is able to produce beneficial effects on gastric mucosa and whether the protective effects of capsipate occur through a mechanism involving the activation of TRPV1 and CGRP release. A rat model of gastric mucosal injury was established by the oral administration of acidified ethanol. Gastric tissues were collected for analysis of the gastric ulcer index, cellular apoptosis, activities of caspase-3, catalase and superoxide dismutase (SOD), and levels of CGRP, TNF-α, and malondialdehyde (MDA). Our results show that the acute administration of ethanol significantly increased the gastric ulcer index concomitantly with an increase in cellular apoptosis, caspase-3 activity, and TNF-α and MDA levels, as well as a decrease in the activities of catalase and SOD. Pretreatment with 1 mg/kg capsiate attenuated ethanol-induced gastric mucosal injury and cellular apoptosis accompanied by an increase in CGRP level, catalase, and SOD activities, and a decrease in caspase-3 activity, and TNF-α and MDA levels. The effects of capsiate were inhibited by capsazepine, an antagonist of TRPV1. These results suggest that capsiate is able to produce beneficial effects on ethanol-induced gastric mucosal injury. These effects are related to the stimulation of CGRP release through the activation of TRPV1.

CALCITONIN GENE-RELATED PEPTIDE MEDIATES THE CARDIOPROTECTIVE EFFECTS OF RUTAECARPINE AGAINST ISCHAEMIA–REPERFUSION INJURY IN SPONTANEOUSLY HYPERTENSIVE RATS

1 It has been shown that calcitonin gene‐related peptide (CGRP) plays an important role in mediating the cardioprotection exerted by rutaecarpine in normal animals. The aim of the present study was to determine whether rutaecarpine is able to decrease the susceptibility of hypertensive animals to ischaemia–reperfusion injury by stimulating CGRP release. 2 Spontaneously hypertensive rats (SHR) were pretreated with rutaecarpine (20 or 40 mg/kg per day, i.g.) for 18 days and then the heart and thoracic aorta were isolated for cardiac function and vascular relaxation analysis. Blood samples and coronary effluent were collected to measure CGRP levels and creatine kinase activity, respectively. The effect of 10 or 30 µmol/L rutaecarpine on CGRP release was also examined in isolated aortic rings set up in a homeothermal organ bath. 3 Rutaecarpine treatment resulted in a hypotensive effect in SHR concomitant with increases in plasma CGRP levels. In addition, rutaecarpine significantly stimulated the release of CGRP from aortic rings. Twenty minutes ischaemia and 30 min reperfusion resulted in a marked decrease in myocardial function and a significant increase in the release of creatine kinase in normal control (Wistar‐Kyoto) rats, an effect that was exacerbated in SHR. Similarly, the decreased vasodilator response to acetylcholine (3 ↔ 10−9 to 10−6 mol/L) in isolated aortic rings from Wistar‐Kyoto rats was also aggravated in SHR. Both cardiac function and vasodilator responses were significantly improved in SHR after pretreatment with rutaecarpine. 4 The results of the present study suggest that the increased cardiac susceptibility to ischaemia–reperfusion injury in SHR is related to decreased plasma CGRP levels and that antihypertensive therapy with rutaecarpine reverses cardiac susceptibility to reperfusion injury by stimulating CGRP release.

Resveratrol derivative BTM-0512 mitigates obesity by promoting beige remodeling of subcutaneous preadipocytes

Recent studies revealed that sirtuin 1 (SIRT1) is involved in the regulation of energy metabolism and its agonist resveratrol showed anti-obesity effect. This study aims to determine whether BTM-0512, a novel derivative of resveratrol, acts as an antagonist of obesity and to explore its possible mechanisms. High-fat diet (HFD)-induced obese mice were intragastrically administered with BTM-0512 (5, 10, and 20 mg/kg/day) or resveratrol (10 mg/kg/day). It was found that the body weight, Lees index, ratio of visceral adipose tissue (VAT) to body weight, and blood glucose were significantly reduced in BTM-0512-treated mice when compared with those in mice treated with resveratrol. BTM-0512 up-regulated the expressions of SIRT1, full length PRDM16 (fPRDM16), total PRDM16 (tPRDM16, including fPPRDM16 and other PRDM16 isoforms), and uncoupling protein 1 (UCP1) in both brown and subcutaneous adipose tissues. Although BTM-0512 and resveratrol also up-regulated SIRT1 and tPRDM16 levels in VAT of HFD-induced obese mice, the expressions of fPRDM16, UCP1, and TMEM26 were down-regulated. In mouse primary subcutaneous preadipocytes cultured with or without adipogenic medium, BTM-0512 up-regulated fPRDM16, tPRDM16, and UCP1 expressions, which was reversed by SIRT1 antagonists. But in cultured brown and visceral adipocytes, the UCP1 protein level showed no significant change after treatment with 1 μM of BTM-0512. Moreover, transfection with human SIRT1 plasmid reduced lipid deposit, as well as the mRNA levels of fPRDM16, UCP1, and TMEM26, in cultured human visceral adipose-derived stem cells. In conclusion, BTM-0512 has stronger anti-obesity effect than resveratrol, which might be associated with activation of beige remodeling in subcutaneous adipose tissue.

Os 32-09 the Beneficial Effect of Losartan on Platelet Aggregation Results From the Reduction of Endogenous Asymmetric Dimethyl Arginine in Spontaneously Hypertensive Rats:

Objective: Previous studies show that platelet aggregation and asymmetric dimethyl arginine (ADMA) are increased in hypertensive patients and animals. However, the relationship between endogenous ADMA and platelet aggregation in spontaneous hypertensive rats (SHR) remains unclear. Since Losartan can increase the nitric oxide (NO) release and ameliorate the state of thrombosis, we aimed to test whether the beneficial effect of losartan on platelet aggregation results from the reduction of ADMA generation. Design and Method: With male Wistar Kyoto rats (WKY) as normal control, we randomly divided male SHR into three groups: SHR control group, L-arginine-treated (1.0 g/kg) and losartan-treated (30 mg/kg) group. For each group, we measured systolic blood pressure (SBP), platelet aggregation rate (pt-Ag), NO level, NOS activity and ADMA content in both plasma and platelets. Results: Compared with WKY rats, the ADMA level in both plasma and in platelets and platelet aggregation rate in SHR were higher, while the NO level and NOS activity were lower. L-arginine (1.0 g/kg) and losartan (30 mg/kg) treatment decreased platelet aggregation rate concomitantly with the decreased level of ADMA and the increased level of NO and the activity of NOS. Incubating platelets from SD rats with thoracic aortic rings for 5 min, the platelet aggregation rate in SHR was higher than that of WKY rats. L-arginine (1.0 g/kg) and losartan (30 mg/kg) significantly reduced the platelet aggregation rate. Conclusions: Our results suggest that endogenous ADMA plays a key role in platelet aggregation, and the beneficial effect of losartan is related to the reduced ADMA level.

Phosphorylation of Nonmuscle Myosin Light Chain Promotes Endothelial Injury in Hyperlipidemic Rats Through a Mechanism Involving Downregulation of Dimethylarginine Dimethylaminohydrolase 2.

Suppression of dimethylarginine dimethylaminohydrolase (DDAH) activation is related to endothelial dysfunction in hyperlipidemia, and nonmuscle myosin regulatory light chain (nmMLC20) has been show to exert transcriptional function in regulation of gene expression. This study aims to explore whether the suppression of DDAH activation promotes endothelial injury under the condition of hyperlipidemia and whether nmMLC20 can regulate DDAH expression in a phosphorylation-dependent manner. The rats were fed with high-fat diet for 8 weeks to establish a hyperlipidemic model, which showed an increase in plasma lipids and endothelial injury, accompanied by an elevation in myosin light chain kinase (MLCK) activity, phosphorylated nmMLC20 (p-nmMLC20) level, and asymmetric dimethylarginine (ADMA) content as well as a reduction in DDAH2 expression, DDAH activity, and nitric oxide (NO) content. Next, human umbilical vein endothelial cells (HUVECs) were incubated with oxidized low-density lipoprotein (ox-LDL; 100 μg/mL) for 24 hours to establish a cellular injury model in vitro. Consistent with the finding in vivo, ox-LDL induced HUVECs injury (apoptosis and necrosis) concomitant with an increase in MLCK activity, p-nmMLC20 level (in total or nuclear proteins), and ADMA content as well as a reduction in DDAH2 expression, DDAH activity, and NO content; these phenomena were attenuated by MLCK inhibitor. Either in hyperlipidemic rats or in ox-LDL-treated HUVECs, there was not significant change in DDAH1 expression. Based on these observations, we conclude that the suppression of DDAH2 expression might account for, at least partially, the vascular endothelial dysfunction in hyperlipidemia, and nmMLC20 plays a role in suppression of DDAH2 expression in a phosphorylation-dependent manner.

Hematopoietic effects of paeoniflorin and albiflorin on radiotherapy and chemotherapy-induced anemia mice

Paeoniflorin (PF), a monoterpene glycoside isolated from P. lactiflora, possesses a variety of pharmacological activities. However, albiflorin (AF), another constituent regarded as a characteristic one, has not been well studied. This study aimed to investigate the hematopoietic effects of AF and PF on anemia mice induced by radiotherapy or chemotherapy and to explore the underlying mechanisms. The anemia mice were irradiated at a dose of 2.5 Gy using cobalt-60 gamma resources or intraperitoneally injected with cyclophosphamide (160.0 mg/kg). The numbers of blood cells from peripheral blood were counted. The thymus index and spleen index were also measured. In addition, of the chemotherapy-induced mice, the levels of TNF-α, GM-CSF, IL-3 in serum were measured by RIA. AF and PF significantly increased the numbers of peripheral blood cells and reversed the atrophy of thymus and spleen. Furthermore, AF and PF increased the levels of GM-CSF and IL-3 and reduce the level of TNF-αin serum.. Our results suggest that AF and PF may promote the recovery of bone marrow hemopoietic function in a myelosuppressed mouse model.