Search

Xu, Chuanli, Yanjie Lu, Guanghua Tang, and Rui Wang. Expression of voltage-dependent [K.sup.+] channel genes in mesenteric artery smooth muscle cells. Am. J. Physiol. 277 (Gastrointest. Liver Physiol. 40): G1055-G1063, 1999.--Molecular basis of native voltage-dependent [K.sup.+] (Kv) channels in smooth muscle cells (SMCs) from rat mesenteric arteries was investigated. The whole cell patch-clamp study revealed that a 4-aminopyridine-sensitive delayed rectifier [K.sup.+] current ([I.sub.K]) was the predominant [K.sup.+] conductance in these cells. A systematic screening of the expression of 18 Kv channel genes using RT-PCR technique showed that six [I.sub.K]-encoding genes (Kv1.2, Kv1.3, Kv1.5, Ky2.1, Kv2.2, and Kv3.2) were expressed in mesenteric artery. Although no transient outward Kv currents ([I.sub.A]) were recorded in the studied SMCs, transcripts of multiple [I.sub.A]-encoding genes, including Kv1.4, Kv3.3, Ky3.4, Ky4.1, Kv4.2, and Kv4.3 as well as [I.sub.A]-facilitating Kv [Beta]-subunits (Kv[Beta], Kv[Beta]2, and Kv[Beta]3), were detected in mesenteric arteries. Western blot analysis demonstrated that four [I.sub.K]-related Kv channel proteins (Kv 1.2, Ky1.3, Ky1.5, and Ky2.1) were detected in mesenteric artery tissues. The presence of Ky1.2, Kv1.3, Kv1.5, and Kv2.1 channel proteins in isolated SMCs was further confirmed by immunocytochemistry study. Our results suggest that the native [I.sub.K] in rat mesenteric artery SMCs might be generated by heteromultimerization of Kv genes. Kv channels; peripheral artery; reverse transcription-polymerase chain reaction; Western blot; immunocytochemistry

TRIM28 is a well-known transcriptional co-repressor of Kruppel-associated box zinc finger proteins. The authors previously demonstrated that TRIM28 small interfering (si)RNA decreases cell proliferation and inhibits cell cycle progression in non-small cell lung cancer (NSCLC) cell lines. The present study further demonstrated that the stable silencing of TRIM28 expression by a specific siRNA lentivirus vector significantly inhibited the growth and exerted obvious anti-tumor effects in nude mice. The results of the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling assay indicated that TRIM28 knockdown increased apoptosis. Furthermore, TRIM28 knockdown decreased the expression of B cell lymphoma (Bcl)-2 and increased the expression of Bcl-2 associated X, apoptosis regulator and p53 at the gene and protein levels. Auto-antibodies to TRIM28 were present in 12.32% of the sera of the patients with NSCLC. The results suggest that TRIM28 knockdown may be effective against NSCLC, and TRIM28 antibodies have the potential to act as novel diagnostic and therapeutic tools. [ABSTRACT FROM AUTHOR]

Background: The role of stress signals in regulating gastric cancer initiation and progression is not quite clear. It is known that stress signals modulate multiple processes such as immune function, cell migration and angiogenesis. However, few studies have investigated the mechanisms of how stress signals contribute to gastric cancer angiogenesis.Methods: Here, we used β2-adrenergic receptor (β2-AR) agonist isoprenaline to imitate a stress signal and demonstrated the molecular mechanism underlying stress's influence on tumor angiogenesis.Results: We found that isoprenaline stimulated vascular endothelial growth factor (VEGF) secretion in gastric cancer cells and plexin-A1 expression was induced by human recombinant VEGF165 in both gastric cancer cells and vascular endothelial cells. Furthermore, interfere with plexin-A1 expression in gastric cancer cells influence HUVEC tube formation, migration and tumor growth in vivo.Conclusions: These findings suggest that isoprenaline stimulate VGEF secretion and subsequently up-regulate the expression of plexin-A1 and VEGFR2 in gastric cancer cells, which form a positive impetus to promote tumor angiogenesis. This study reveals a novel molecular mechanism that a stress signal like isoprenaline may enhance angiogenesis via activating plexin-A1/VEGFR2 signaling pathway in gastric cancer, which may be a potential target in development of an anti-angiogenic therapy for gastric cancer. [ABSTRACT FROM AUTHOR]

Melatonin, a hormone secreted by the pineal gland, possesses multiple biological activities such as antitumor, antioxidant, and anti-ischemia. C-kit+ cardiac progenitor cells ( CPCs) have emerged as a promising tool for the treatment of heart diseases. However, the senescence of CPCs due to pathological stimuli leads to the decline of CPCs' functions and regenerative potential. This study was conducted to demonstrate whether melatonin antagonizes the senescence of CPCs in response to oxidative stress. Here, we found that the melatonin treatment markedly inhibited the senescent characteristics of CPCs after exposed to sublethal concentration of H2O2, including the increase in senescence-associated β-galactosidase ( SA- β-gal)-positive CPCs, senescence-associated heterochromatin loci ( SAHF), secretory IL-6 level, and the upregulation of p53 and p21 proteins. Senescence-associated proliferation reduction was also attenuated by melatonin in CPCs. Luzindole, the melatonin membrane receptor blocker, may block the melatonin-mediated suppression of premature senescence in CPCs. Interestingly, we found that long noncoding RNA H19 and its derived miR-675 were downregulated by H2O2 in CPCs, but melatonin treatment could counter this alteration. Furthermore, knockdown of H19 or miR-675 blocked antisenescence actions of melatonin on H2O2-treated CPCs. It was further verified that H19-derived miR-675 targeted at the 3′ UTR of USP10, which resulted in the downregulation of p53 and p21 proteins. In summary, melatonin antagonized premature senescence of CPCs via H19/miR-675/ USP10 pathway, which provides new insights into pharmacological actions and potential applications of melatonin on the senescence of CPCs. [ABSTRACT FROM AUTHOR]

Background/Aims: Acute myocardial infarction (AMI) is a devastating cardiovascular disease with a high rate of morbidity and mortality, partly due to enhanced arrhythmogenicity. MicroRNAs (miRNAs) have been shown to participate in the regulation of cardiac ion channels and the associated arrhythmias. The purpose of this study was to test our hypothesis that miR-223-3p contributes to the electrical disorders in AMI via modulating KCND2, the gene encoding voltage-gated channel Kv4.2 that carries transient outward K+ current Ito. Methods: AMI model was established in male Sprague-Dawley (SD) rats by left anterior descending artery (LAD) ligation. Evans blue and TTC staining was used to measure infarct area. Ito was recorded in isolated ventricular cardiomyocytes or cultured neonatal rat ventricular cells (NRVCs) by whole-cell patch-clamp techniques. Western blot analysis was employed to detect the protein level of Kv4.2 and real-time RT-PCR to determine the transcript level of miR-223- 3p. Luciferase assay was used to examine the interaction between miR-223-3p and KCND2 in cultured NRVCs. Results: Expression of miR-223-3p was remarkably upregulated in AMI relative to sham control rats. On the contrary, the protein level of Kv4.2 and Ito density were significantly decreased in AMI. Consistently, transfection of miR-223-3p mimic markedly reduced Kv4.2 protein level and Ito current in cultured NRVCs. Co-transfection of AMO-223-3p (an antisense inhibitor of miR-223-3p) reversed the repressive effect of miR-223-3p. Luciferase assay showed that miR-223-3p, but not the negative control, substantially suppressed the luciferase activity, confirming the direct binding of miR-223-3p to the seed site within the KCND2 sequence. Finally, direct intramuscular injection of AMO-223-3p into the ischemic myocardium to knockdown endogenous miR-223-3p decreased the propensity of ischemic arrhythmias. Conclusions: Upregulation of miR-223-3p in AMI repressed the expression of KCND2/Kv4.2 resulting in reduction of Ito density that can cause APD prolongation and promote arrhythmias in AMI, and therefore knockdown of endogenous miR-223-3p might be considered a new approach for antiarrhythmic therapy of ischemic arrhythmias. [ABSTRACT FROM AUTHOR]

The peanut-shaped monoclinic scheelite BiVO 4 crystals were synthesized via a facile one step hydrothermal method without using any templates, followed by annealing at different temperatures. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Brunauer-Emmet-Teller (BET) and UV–vis diffuse reflectance spectra (DRS), showing that the annealing procedure could not only change the surface morphology and crystallinity of BiVO 4 but also increase the specific surface area without damaging the peanut shape. The band gap values of the samples annealed at different temperatures could be reduced to 2.44–2.46 eV as compare with that of 2.47 eV of the original sample. The photocatalytic activities of BiVO 4 crystals were evaluated by degradation of methylene blue in aqueous solution under artificial solar-light. Results demonstrated that the sample annealed at 450 °C exhibited the highest activity, and the photocatalytic conversion of methylene blue could reach above 94% after 150 min of irradiation. [ABSTRACT FROM AUTHOR]

Background and Purpose: Pressure overload-induced cardiac interstitial fibrosis is viewed as a major cause of heart failure in patients with hypertension or aorta atherosclerosis. The purpose of this study was to investigate the effects and the underlying mechanisms of genistein, a natural phytoestrogen found in soy bean extract, on pressure overload-induced cardiac fibrosis.Experimental Approach: Genisten was administered to mice with pressure overload induced by transverse aortic constriction. Eight weeks later, its effects on cardiac dysfunction, hypertrophy and fibrosis were determined. Its effects on proliferation, collagen production and myofibroblast transformation of cardiac fibroblasts (CFs) and the signalling pathways were also assessed in vitro.Key Results: Pressure overload-induced cardiac dysfunction, hypertrophy and fibrosis were markedly attenuated by genistein. In cultured CFs, genistein inhibited TGFβ1-induced proliferation, collagen production and myofibroblast transformation. Genistein suppressed TGFβ-activated kinase 1 (TAK1) expression and produced anti-fibrotic effects by blocking the TAK1/MKK4/JNK pathway. Further analysis indicated that it up-regulated oestrogen-dependent expression of metastasis-associated gene 3 (MTA3), which was found to be a negative regulator of TAK1. Silencing MTA3 by siRNA, or inhibiting the activity of the MTA3-NuRD complex with trichostatin A, abolished genistein's anti-fibrotic effects.Conclusions and Implications: Genistein improved cardiac function and inhibited cardiac fibrosis in response to pressure overload. The underlying mechanism may involve regulation of the MTA3/TAK1/MKK4/JNK signalling pathway. Genistein may have potential as a novel agent for prevention and therapy of cardiac disorders associated with fibrosis. [ABSTRACT FROM AUTHOR]

Ventricular hypertrophy is a powerful and independent predictor of cardiovascular morbid events. The vascular properties of low-dose acetyl salicylic acid (aspirin) provide cardiovascular benefits through the irreversible inhibition of platelet cyclooxygenase 1; however, the possible anti-hypertrophic properties and potential mechanism of aspirin have not been investigated in detail. In this study, healthy wild-type male mice were randomly divided into three groups and subjected to transverse aortic constriction (TAC) or sham operation. The TAC-operated mice were treated with the human equivalent of low-dose aspirin (10 mg·kg·d); the remaining mice received an equal amount of phosphate buffered saline with 0.65% ethanol, which was used as a vehicle. A cardiomyocyte hypertrophy model induced by angiotensin II (10 nmol·L) was treated with the human equivalent of low (10 or 100 μmol·L) and high (1000 μmol·L) aspirin concentrations in plasma. Changes in the cardiac structure and function were assessed through echocardiography and transmission electron microscopy. Gene expression was determined through RT-PCR and western blot analysis. Results indicated that aspirin treatment abrogated the increased thickness of the left ventricular anterior and posterior walls, the swelling of mitochondria, and the increased surface area in in vivo and in vitro hypertrophy models. Aspirin also normalized the upregulated hypertrophic biomarkers, β-myosin heavy chain (β-MHC), atrial natriuretic peptide (ANP), and b-type natriuretic peptide (BNP). Aspirin efficiently reversed the upregulation of β-catenin and P-Akt expression and the TAC- or ANG II-induced downregulation of GSK-3β. Therefore, low-dose aspirin possesses significant anti-hypertrophic properties at clinically relevant concentrations for anti-thrombotic therapy. The downregulation of β-catenin and Akt may be the underlying signaling mechanism of the effects of aspirin. [ABSTRACT FROM AUTHOR]

In the version of this article initially published, lanes from the original blot shown in Figure 2b (NIZ and IZ samples, blotting for 55-kDa Kir2.1 and GAPDH) were rearranged in [...]