Design, synthesis and anti-Alzheimer's disease activity evaluation of C-3 arylated huperzine A derivatives.

A series of C-3 arylated huperzine A (HPA) derivatives (1-30) were designed and synthesized in good yields via palladium-catalyzed Suzuki cross-coupling reaction. Cholinesterase inhibitory and neuroprotective activities of all 30 derivatives were evaluated. Cholinesterase inhibition results revealed that derivatives 2 and 15 exhibited dual inhibitory activity against both acetylcholinesterase (AChE inhibition: 2, IC50 = 1.205 ± 0.395 µM; 15, IC50 = 0.225 ± 0.062 µM) and butyrylcholinesterase (BChE inhibition: 2, IC50 = 8.598 ± 3.605 µM; 15, IC50 = 4.013 ± 0.068 µM), a feature not observed in huperzine A. Molecular docking results indicated that the introduction of aryl groups enhanced the affinity of the derivatives for the acyl-binding pocket of BChE, thereby limiting the hydrolysis of acetyl choline. However, these derivatives exhibited poor performance in cytotoxicity and neuroprotection assays.

Infrasound exposure induces apoptosis of rat cardiac myocytes by regulating the expression of apoptosis-related proteins.

It has been reported that exposure to infrasound causes cardiac dysfunction. Allowing for the key role of apoptosis in the pathogenesis of cardiovascular diseases, the objective of this study was to investigate the apoptotic effects of infrasound. Cardiac myocytes cultured from neonatal rats were exposed to infrasound of 5 Hz at 130 dB. The apoptosis was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. Also, the expression levels of a series of apoptosis-related proteins were detected. As a result, infrasound induced apoptosis of cultured rat cardiac myocytes in a time-dependant manner. The expression of proapoptotic proteins such as Bax, caspase-3, caspase-8, caspase-9, and FAS was significantly up-regulated, with concomitant down-regulated expression of antiapoptotic proteins such as Bcl-x, and the inhibitory apoptosis proteins family proteins including XIAP, cIAP-1, and cIAP-2. The expression of poly (ADP-ribose) polymerase and ß-catenin, which are the substrate proteins of caspase-3, was significantly decreased. In conclusion, infrasound is an apoptotic inducer of cardiac myocytes.

AC-NP: a novel chimeric peptide with natriuretic and vasorelaxing actions.

The aim of this study was to evaluate the cardiovascular and renal activities of a newly designed natriuretic peptide (NP). Here, we engineered a novel 28-amino acid chimeric peptide, termed AC-NP that combined the 17-amino acid ring of C type natriuretic peptide (CNP) with the 6-amino acid N-terminus and 5-amino acid C-terminus of atrial natriuretic peptide (ANP). Both in vitro and in vivo experiments were performed to determine the actions of AC-NP. In normal rats, AC-NP proved to be more potentially diuretic, natriuretic and hypotensive compared with other NPs, such as ANP, CNP and vasonatrin peptide (VNP), which is another man-made NP. In relaxation of isolated abdominal aorta from rat, AC-NP was equally effective to ANP, CNP and VNP. Elevated levels of 3',5'-guanosine monophosphate (cGMP) in plasma and urine cGMP excretion indicated the participation of cGMP in the functions of AC-NP. Taken together, innovative designed AD-NP might be a new candidate therapeutic peptide against cardiorenal disorders.

Protecting effects of vasonatrin peptide against carbon tetrachloride-induced liver fibrosis.

In order to investigate the effects of vasonatrin peptide (VNP), a novel man-made natriuretic peptide, on liver fibrosis, mice received carbon tetrachloride (CCl(4)) injection for 12weeks and with or without VNP treatment during the last 6weeks. Hematoxylin-eosin (HE) staining and Sirius red staining were performed to evaluate the status of liver fibrosis. After treatment of VNP, DNA and collagen synthesis of cultured HSC-T6 hepatic stellate cells were assessed by [(3)H]-thymidine and [(3)H]-proline incorporation, respectively. Additionally, involved signaling pathway was identified by radioimmunoassay to detect the levels of intracellular cGMP and by mimicking experiments using 8-br-cGMP (a membrane-permeable cGMP analog). Also, blocking experiments were performed using HS-142-1, an antagonist of guanylyl cyclase-coupled natriuretic peptide receptor (NPR), or KT-5823, the cGMP-dependent protein kinase (PKG) inhibitor. As a result, VNP markedly alleviated CCl(4)-induced liver fibrosis in mice. In vitro, HSC-T6 cells demonstrated a dose-dependent reduction of DNA and collagen synthesis in the presence VNP. In addition, VNP significantly increased the intracellular levels of cGMP. These effects of VNP were mimicked by 8-br-cGMP, although inhibited by HS-142-1 or KT-5823. Taken together, VNP ameliorates liver fibrosis by inhibiting collagen production from hepatic stellate cells via guanylyl cyclase-coupled NPR/cGMP/PKG pathway, indicating that VNP might be a new effective reagent in the treatment of liver fibrosis.

Protective effects of vasonatrin peptide against hypobaric hypoxia-induced pulmonary hypertension in rats.

1. The aim of the present study was to investigate the in vivo effects of vasonatrin peptide (VNP) on hypoxia-induced pulmonary hypertension (HPH). 2. The HPH model was developed by subjecting rats to hypobaric hypoxia. The HPH rats were then treated with either VNP (50 microg/kg per day, i.p.) or saline (0.5 mL, i.p.) every day for 7 days. Haemodynamic indices, right ventricular hypertrophy (RVH) and remodelling of the pulmonary arteries were evaluated. In addition, plasma levels of atrial natriuretic peptide (ANP), endothelin (ET)-1 and angiotensin II (AngII) were determined, as was natriuretic peptide receptor-C (NPR-C) mRNA expression in the right ventricle. 3. Hypobaric hypoxia induced severe HPH compared with the normoxic control group. Treatment of HPH rats with VNP for 1 week significantly reduced mean pulmonary arterial pressure, pulmonary vascular resistance, RVH and muscularization of the pulmonary arteries, although pulmonary blood flow was increased in this group. In addition, significantly lower levels of plasma ET-1 and AngII and cardiac NPR-C mRNA expression were observed in VNP-treated compared with saline-treated HPH rats, whereas higher plasma concentrations of ANP were found in the former group. Acute intravenous administration of 50 microg/kg VNP significantly ameliorated pulmonary haemodynamics in HPH rats. 4. Taken together, the date indicate that VNP has certain preventative and therapeutic effects against HPH.

[Expression of ICOSL on human coronary artery endothelial cells and its being interferentialed by ox-LDL].

AIM: To study the expression of inducible co-stimulator ligand(ICOSL) on human coronary artery endothelial cells(HCAEC) and its being interferentialed by oxidized low density lipoprotein(ox-LDL). METHODS: ICOSL expression levels were determined by the fluorescence, reverse transcription PCR (RT-PCR) and Western blot, respectively. RESULTS: The ICOSL mRNA OD values of control and 100 mg/L ox-LDL group was 0.071+/-0.035 and 0.186+/-0.044, respectively. The Western blot A values of control and 100 mg/L ox-LDL group was 10.88+/-1.53 and 16.03+/-4.08, respectively. ox-LDL increased expression of ICOSL mRNA and protein(P<0.05). CONCLUSION: ICOSL can express on the HCAEC. ox-LDL can up-regulate the expression of ICOSL.

[Inhibitory effects of rosiglitazone against endothelin-1-induced proliferation of rat cardiac myocytes: the role of PKC-c-fos pathway].

OBJECTIVE: To investigate the mechanism of rosiglitazone (RSG, the activator of peroxisome proliferators activated receptor lambda) for inhibiting endothelin-1 (ET-1)-induced neonatal rat cardiac myocyte hypertrophy and the role of protein kinase C (PKC) and c-fos. METHODS: In vitro cultured neonatal rat cardiac myocytes were treated with ET-1, phorbol ester (PMA, the PKC activator), ET-1+RSG, ET-1+chelerythrine (che, the PKC inhibitor), PMA+RSG, or without treatment (control), respectively. The effects of RSG on the protein content, (3)H-leucine incorporation, PKC activity and C-fos protein expression were observed in the cardiac myocytes stimulated with ET-1 or PMA. RESULTS: After two days of culture, the intracellular protein content in ET-1 group and PMA group were increased by 15% (339-/+15 microg/ml) and 13% (329-/+14 microg/ml) as compared with the control cells (290-/+13 microg/ml), respectively (P<0.01). Compared with the ET-1 group, cells treated with ET-1+10(-8) mol/L RSG, ET-1+10(-7) mol/L RSG, and ET-1+che showed decreased intracellular protein content by 10% (303-/+14 microg/ml, P<0.05), 12% (292-/+11 microg/ml, P<0.05), and 13% (291-/+12 microg/ml, P<0.01), respectively. The intracellular protein content in PMA+10(-7) mol/LRSG group was decreased by 10% (P<0.05) in comparison with the PMA group. RSG inhibited protein synthesis enhancement and increased (3)H-leucine incorporation induced by ET-1 and PMA, and antagonized the effects of ET-1 and PMA in promoting PKC activity and c-fos protein expression in the myocytes. CONCLUSION: The inhibitory effect of RSG on ET-1- or PMA-induced myocyte hypertrophy is associated with PKC-c-fos pathway.

[Relationship between cardiomyocyte protein synthesis and cell viability].

OBJECTIVE: To observe the relationship between protein sythesis and cardiomyocyte viability in neonatal rats. METHODS: The protein sythesis in neonatal rat cardiomyocytes was measured according to Brandford's method, the absorbance at 490 nm (A(490 nm)) of the cells was measured with MTT assay and the cell viability evaluated by the ratio of A(490 nm) to the total cell number. RESULTS: ET-1 increased cardiomyocyte protein synthesis dose-dependently, and this effect was attenuated by the application of lacidipine and tetramethylpyrazines Higher doses of ET-1 resulted in lower A(490 nm)/total cell number ratio, which was further lowered by larcidipine and tetramethylpyrazine. CONCLUSION: The status of protein synthesis is not associated with the viability of neonatal rat cardiomyocytes.

[Analysis of inflammatory reaction of atherosclerosis model].

OBJECTIVE: To analysis and evaluate the inflammatory reaction of atherosclerosis model in rabbits. METHOD: A model of atherosclerosis in rabbits was estabalished by injury with balloon and high cholesterol diet to observe the dynamic change of serum inflammation markers c-reactive protein, interleukin-1beta and tumor necrosis factor-a, and the relationship between severity of AS lesion and those change. RESULT: (1) The levels of TNF-alpha at 4 time points: 1, 6, 10 weeks and 10 weeks + 1 day after balloon injury increased 1.6-fold, 2.2-fold, 4-fold, 2-fold over concurrent control, respectively (P < 0.05, P < 0.01, P < 0.01, P < 0.01), but no significant changes occurred during the observation. (2) At the end of the 6, 10 weeks and 10 weeks + 1 day, the levels of CRP were increased 3.5-fold, 3.6-fold, 3.0-fold than concurrent control (P < 0.01, P < 0.01, P < 0.01), respectively. The levels were increased 2.4-fold at the end of the 6 weeks and 4.1-fold at the end of the 10 weeks and reached the peak compared with the point of 1 week. (3) TNF-alpha and CRP showed a significant positive correlation with the MIT (correlation coefficients were found to be 0.61, 0.64, P < 0.01). (4) At the end of the 1, 6, 10 weeks, the model was provided with general pathological characteristics and the inflammatory reaction of earlier inflammatory reaction phase, fatty streak plaques phase, fibrous plaque phase respectively. CONCLUSION: The model was provided with early and medial phase typical feature of atherosclerotic lesion, and showed a significant positive correlation with the inflammatory factor expression. At the end of the 6 weeks, the formation of fatty streak plaques and obvious inflammatory reaction could be satisfied for the interference in forming process of AS from dimension of inflammatory and screening assays of drugs.

[Protective effects of nitric oxide donor on hydrogen peroxide-induced injury of cardiomyocytes].

To investigate the protective effects of nitric oxide (NO) on cardiomyocytes against hydrogen peroxide (H2O2)-induced injury, cultured neonatal cardiomyocytes were divided into three groups: (1) normal group; (2) H2O2 group: cells were treated with H2O2 (0.1 mmol/L) for 4 h; (3) SNAP+ H2O2 group: cells were pretreated with NO donor S-nitroso-N-acetyl-1,1-penicillamine (SNAP, 0.5 mmol/L) 10 min before H2O2 treatment. Colorimetric assay was used to detect cell viability and lactate dehydrogenase (LDH) activity to evaluate cell injury. Apoptotic rate of cardiomyocytes were determined by flow cytometer. Superoxide dismutase (SOD) activity and malonaldehyde (MDA) content were measured by colorimetric assay to evaluate cell antioxidant ability. Intracellular calcium was tested by laser confocal microscopy. The results showed that after treatment with H2O2, cell viability was significantly reduced to 58.3+/-7.6% compared with normal group (93.1+/-6.2 %). LDH activity and apoptotic rates were 1580.5+/-186.7 U/L and 26.4+/-5.7% respectively, significantly higher than that of normal group (631.4+/-75.6 U/L and 0). SNAP pretreatment markedly improved cell viability to 79.7+/-9.3% and reduced LDH activity and apoptotic rates to 957.8+/-110.9 U/L and 9.1+/-3.3%, respectively. Cells treated with H2O2 had a lower SOD activity of 14.73+/-1.68 NU/ml and a higher MDA content of (15.35+/-3.49) micromol/L compared with normal cells (19.67+/-0.85 NU/ml) and (6.95+/-0.83 micromol/L), respectively. Cells with SNAP pretreatment had a higher SOD activity of 21.36+/-3.11 NU/ml and a lower MDA content of 9.12+/-1.47 micromol/L compared with H2O2 group. Intracellular calcium content was reduced by SNAP administration while enhanced by H2O2. Pretreatment with SNAP could antagonize the effect of H2O2 of accelerating intracellular calcium content. Based on the results observed, it is concluded that NO donor SNAP may protect cardiomyocytes from being injured by H2O2. The underlying mechanisms may include improving cell antioxidant ability and reducing intracellular calcium overload.