Mitochondrial KATP channel-mediated autophagy contributes to angiotensin II-induced vascular dysfunction in mice.

BACKGROUND AND AIM: The present study aimed to investigate whether the mitochondrial KATP channel contributes to angiotensin II (Ang II)-induced vascular dysfunction, the development of hypertension, and atherosclerosis. METHODS AND RESULTS: ApoE (-/-) mice fed a high-fat diet were chronically infused with Ang II for eight weeks and concomitantly treated with losartan (ARB), apocynin, or 5-hydroxy decanoate (5-HD), or 3-methyladenine (3-MA). Systolic blood pressure was measured, and pathological changes of aortic or liver tissue were observed. Nitric oxide (NO), superoxide dismutase 2 (SOD2) levels and vasorelaxation rate were measured, and protein and mRNA expressions were examined by western blot and RT-PCR. Ang II-induced development of hypertension was suppressed not only by ARB, and apocynin but also by 5-HD or 3-MA. Ang II infusion decreased aortic NO production and relaxation, as well as SOD2 activity in liver, which were improved by all treatments. In addition, Ang II-induced activation of autophagy was suppressed by 5-HD in aortic tissue, furthermore, Ang II increases the atherosclerotic index in plasma and exacerbates the development of atherosclerosis by increases of fat deposition in the aorta and liver. Lipid metabolism-related mRNA expressions (LXR-α, LDLR, SRBI, Acca, and FASN) were changed by Ang II. Similarly, not only ARB, and apocynin, but also 5-HD and 3-MA suppressed Ang II-induced these changes. CONCLUSIONS: Our present findings evidence that mitochondrial KATP channel-mediated autophagy contributes to Ang II-induced vascular dysfunction, development of hypertension, and atherosclerosis.

A strategy to comprehensively analyze the bioactivity of complex herbal prescriptions via peak-by-peak cutting and knock-out chromatography: Qiliqiangxin capsule as an example.

An herbal prescription is usually composed of several herbal medicines. The complex and diverse components bring great challenges to its bioactivity study. To comprehensively analyze the bioactivity of an herbal prescription, a new strategy based on peak-by-peak cutting and knock-out chromatography was proposed. In this strategy, active compounds were screened out via peak-by-peak cutting from an herbal extract, and the influence of a compound on the overall activity of the herbal extract was evaluated by knock-out chromatography. Qiliqiangxin capsule is an herbal prescription composed of 11 herbal medicines for the treatment of chronic heart failure. A total of 71 peaks were collected through peak-by-peak cutting, and each peak was identified by a high-resolution mass spectrum. The bioassay against 1,1-diphenyl-2-picrylhydrazyl showed that two types of compounds namely salvianolic acids and caffeoylquinic acids were potent scavengers. Knock-out chromatography suggested that the removal of one single compound had no obvious influence on the overall activity of the Qiliqiangxin capsule. After all the main peaks in the Qiliqiangxin capsule were knocked out, the remaining part still exhibited a potent activity, indicating high activity stability of the Qiliqiangxin capsule. The proposed strategy is helpful for the comprehensive analysis of the bioactivity of other herbal prescriptions.

Cardioprotective Effects of Serca2a Overexpression Against Ischemiareperfusion- induced Injuries in Rats.

AIMS: The aim of the present study was to assess how genetically increased Sarcoplasmic reticulum Ca2+-ATPase (Serca2a) expression affects cardiac injury after Ischemia/Reperfusion (I/R) exposure and the related mechanisms involved. METHODS AND RESULTS: Rats were subjected to Left Anterior Descending coronary artery (LAD) occlusion for 30 min followed by a 24-hour reperfusion. Cardiac function analysis revealed that cardiac function dramatically improved in Serca2a transgenic rats, (Serca2aTG) rats, compared to Wild Type (WT) rats. Serca2aTG rats developed a significantly smaller myocardial infarction size compared to those in WT group. The expression of the Bcl-2 was lower in Serca2aTG rats compared with WT rats; but, Bcl-2 expression was markedly increased in Serca2aTG rats compared with WT after I/R. In addition, Bax was markedly downregulated in Serca2aTG rats compared to WT group after I/R. Meanwhile, autophagy marker LC-3B was increased in Serca2aTG group, and p62 was only increased in WT group but not in Serca2aTG group in response to I/R. Electron microscope observation confirmed that there were more autophagosomes in Serca2aTG group than in WT rats after I/R. CONCLUSION: our findings demonstrated that the overexpression of Serca2a plays an important role in myocardial protection from I/R injury and postischemic functional recovery, which may be via antinecrotic, anti-apoptotic and pro-autophagy signal pathways. Our research provides solid basic data and new perspective on clinical treatment in heart failure patients with long-term over-expression of Serca2a.

Whole Blood PCR Amplification with Pfu DNA Polymerase and Its Application in Single-Nucleotide Polymorphism Analysis.

AIMS: Point-of-care genetic analysis may require polymerase chain reaction (PCR) to be carried out on whole blood. However, human blood contains natural inhibitors of PCR such as hemoglobin, immunoglobulin G, lactoferrin, and proteases, as well as anticoagulant agents, including EDTA and heparin that can reduce whole blood PCR efficiency. Our purpose was to develop a highly specific, direct whole blood single-nucleotide polymorphism (SNP) analysis method based on allele-specific (AS) PCR that is mediated by Pfu DNA polymerase and phosphorothioate-modified AS primers. RESULTS: At high Mg(2+) concentrations, Pfu DNA polymerase efficiently amplified genomic DNA in a reaction solution containing up to 14% whole blood. Among the three anticoagulants tested, Pfu DNA polymerase showed the highest activity with sodium citrate. Meanwhile, Triton X-100 and betaine inhibited Pfu DNA polymerase activity in whole blood PCR, whereas trehalose had virtually no effect. These findings provided for the development of a low-cost, simple, and fast direct whole blood genotyping method that uses Pfu DNA polymerase combined with phosphorothioate AS primers for CYP2C9*3 and VKORC1(-1639) loci. CONCLUSIONS: With its high DNA amplification efficiency and tolerance of various blood conditions, Pfu DNA polymerase can be used in clinical laboratories to analyze SNPs in whole blood samples.

Role of the renin-angiotensin system, renal sympathetic nerve system, and oxidative stress in chronic foot shock-induced hypertension in rats.

OBJECTIVE: The renin-angiotensin system (RAS) and renal sympathetic nerve system (RSNS) are involved in the development of hypertension. The present study is designed to explore the possible roles of the RAS and the RSNS in foot shock-induced hypertension. METHODS: Male Sprague-Dawley rats were divided into six groups: control, foot shock, RSNS denervation, denervation plus foot shock, Captopril (angiotensin I converting enzyme inhibitor, ACE inhibitor) plus foot shock, and Tempol (superoxide dismutase mimetic) plus foot shock. Rats received foot shock for 14 days. We measured the quantity of thiobarbituric acid reactive substances (TBARS), corticosterone, renin, and angiotensin II (Ang II) in plasma, the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and renal noradrenaline content. RAS component mRNA and protein levels were quantified in the cerebral cortex and hypothalamus. RESULTS: The two week foot shock treatment significantly increased systolic blood pressure, which was accompanied by an increase in angiotensinogen, renin, ACE1, and AT1a mRNA and protein expression in the cerebral cortex and hypothalamus, an increase of the plasma concentrations of renin, Ang II, corticosterone, and TBARS, as well as a decrease in plasma SOD and GSH-Px activities. Systolic blood pressure increase was suppressed by denervation of the RSNS or treatment with Captopril or Tempol. Interestingly, denervation or Tempol treatment both decreased main RAS components not only in the circulatory system, but also in the central nervous system. In addition, decreased antioxidant levels and increased TBARS and corticosterone levels were also partially restored by denervation or treatment with Tempol or Captopril. CONCLUSIONS: RAS, RSNS and oxidative stress reciprocally potentiate to play important roles in the development of foot shock-induced hypertension.

A novel anti-human syndecan-1 (CD138) monoclonal antibody 4B3: characterization and application.

Syndecan-1 (CD138), a member of integral membrane heparin sulfate proteoglycans, is an essential matrix receptor for maintaining the normal morphological phenotypes. In this study, we generated a specific mouse anti-human syndecan-1 monoclonal antibody (mAb) 4B3 and identified it by competition assay with the available syndecan-1 mAb (BB4). Stained by 4B3, the expression of syndecan-1 was detected on tumor cell lines, such as 8226, U266, XG-1, XG-2, Daudi and Jurkat. The expression was also found on neuron stem cells. It was established that 4B3 mAb could inhibit XG-1 and XG-2 proliferation. The data not only determined that 4B3 mAb was a functional anti-human syndecan-1 mAb, but also indicated that syndecan-1 might be a valuable surface antigen and play an important role in regulation of tumor pathology and differentiation of neural stem cells. This novel antibody 4B3 may be value of study of tumor proliferation/survival mechanism and contributes to diagnosis and treatment of diverse diseases.

[A receptors in the NTS modulate depression of carotid baroreflex induced by intracerebroventricular injection of histamine in rats].

AIM: To investigate the roles of alpha1 and alpha2 receptors in the nucleus tractus solitarius (NTS) in the carotid baroreflex (CBR) resetting induced by the intracerebroventricular injection (ICV) of histamine (HA). METHODS: The left and right carotid sinus regions were isolated from the systemic circulation in 25 Sprague-Dawley rats anesthetized with pentobarbital sodium. The intracarotid sinus pressure (ISP) was altered in a stepwise manner. ISP-mean arterial pressure (MAP) relationship curve and its characteristic parameters were constructed by fitting to the logistic function with five parameters. The changes in CBR performance induced by ICV HA and the effects of pretreatment with alpha1 or alpha2 receptor antagonist into the NTS on the responses of CBR to HA were examined. RESULTS: ICV HA (60 micromol x L(-1) in 5 microl) significantly shifted the ISP-MAP relationship curve upwards (P < 0.05) and moved the middle part of ISP-Gain relationship curve downwards (P < 0.05), and reduced the MAP range and maximum gain (P < 0.05). The pretreatment with phenoxybenzamine (PBZ, a selective antagonist of alpha1 receptor, 3 micromol x L(-1) in 500 nl) or yohimbine (YOH, a selective antagonist of alpha2 receptor, 2.5 micromol x L(-1) in 500 nl) into the NTS could obviously intensify the above-mentioned changes in CBR performance induced by HA, but the intensive effect of PBZ was less remarkable than that of YOH (P < 0.05). CONCLUSION: The intracerebroventricular administration of HA results in a rapid resetting of CBR and a decrease in reflex sensitivity, and the functions of alpha1 and alpha2 receptors in the NTS might weaken CBR resetting induced by ICV HA. Furthermore, alpha2 receptor in the NTS might play an more important role in modulating the responses of CHR to HA.

[Roles of the histaminergic receptors in the locus ceruleus in stress-induced carotid baroreflex resetting in rats].

AIM: To explore the roles of H1 and H2 receptors in the locus ceruleus (LC) in the carotid baroreflex (CBR) resetting resulted from foot-shock stress. METHODS: Male SD rats were divided into two groups (n=18) at random: unstressed and stressed group. The latter were subjected to unavoidable electric foot-shock twice daily for a week and each session of foot-shock lasted 2 hours. The left and right carotid sinus regions were isolated from the systemic circulation in all animals anesthetized with pentobarbital sodium. The intracarotid sinus pressure (ISP) was altered in a stepwise manner in vivo. ISP-mean arterial pressure (MAP), ISP-Gain relationship curves and reflex characteristic parameters were constructed by fitting to the logistic function with five parameters. The changes in CBR performance induced by stress and the effects of microinjection with histaminergic receptors antagonists into the LC on the responses of CBR to stress were examined. RESULTS: Stress significantly shifted the ISP-MAP relationship curve upwards (P < 0.05) and obviously moved the middle part of ISP-Gain relationship curve downwards (P < 0.05), and decreased the value of the MAP range and maximum gain (P < 0.05), but increased the threshold pressure, saturation pressure, set point and ISP at maximum gain (P < 0.05). Microinjection of selective H1 or H2 receptor antagonist, chlorpheniramine (CHL, 0.5 microg/microl) or cimetidine (CIM, 1.5 microg/microl) into the LC, significantly attenuated the above-mentioned changes in CBR performance induced by stress and the alleviate effect of CIM was less remarkable than that of CHL (P < 0.05). The responses of CBR under stress to H1 or H2 receptor antagonist generally occurred 20 min after the administration and lasted approximately for 16 min. Microinjection with the same dose of CHL or CIM into the LC in the unstressed group did not change CBR performance significantly (P > 0.05). However, microinjection of CHL or CIM into the LC could not completely abolish the stress-induced changes in CBR. CONCLUSION: The stress results in a resetting of CBR and a decrease in reflex sensitivity. The stress-induced changes in CBR may be mediated, at least in part, by activating the brain histaminergic system. The H1 and H2 receptors in the LC, especially, Hi receptors may play an important role in the resetting of CBR under stress. The descending histaminergic pathway from the hypothalamus to LC may be involved in these effects. Moreover, the effects of stress on CBR also have other mechanisms.

H(1) and H(2) receptors in the locus ceruleus are involved in the intracerebroventricular histamine-induced carotid sinus baroreceptor reflex resetting in rats.

Objective To investigate the role of H(1) and H(2) receptors in the locus ceruleus (LC) in carotid sinus baroreceptor reflex (CSR) resetting induced by intracerebroventricular (i.c.v.) injection of histamine (HA). Methods The left and right carotid sinus regions were isolated from the systemic circulation in 18 male Sprague-Dawley rats anesthetized with pentobarbital sodium. The intracarotid sinus pressure (ISP) was altered in a stepwise manner in vivo. ISP-mean arterial pressure (MAP) relationship curve and its characteristic parameters were constructed by fitting to the logistic function with five parameters. The changes in CSR performance induced by i.c.v. HA and the effects of pretreatment with H(1) or H(2) receptors selective antagonist, chlorpheniramine (CHL) or cimetidine (CIM) into the LC, on the responses of CSR to HA were examined. Results I.c.v. HA (100 ng in 5 mu l) significantly shifted the ISP-MAP relationship curve upwards (P < 0.05) and obviously decreased the value of the reflex parameters such as MAP range and maximum gain (P < 0.05), but increased the threshold pressure, saturation pressure and ISP at maximum gain (P < 0.05). The pretreatment with CHL (0.5 mu g in 1 mu l) or CIM (1.5 mu g in 1 mu l) into the LC could obviously attenuate the changes mentioned above in CSR performance induced by HA, but the alleviative effect of CIM was less remarkable than that of CHL (P < 0.05). Respective microinjection of CHL or CIM alone into the LC with the corresponding dose and volume did not change CSR performance significantly (P > 0.05). Conclusion Intracerebroventricular administration of HA results in a rapid resetting of CSR and a decrease in reflex sensitivity, and the responses of CSR to HA may be mediated, at least in part, by H(1) and H(2) receptors activities in the LC, especially by H(1) receptors. Moreover, the effects of the central HA on CSR might be related to a histaminergic descending pathway from the hypothalamus to LC.