• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.5
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• pp.1233-1240
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• 2006

We have recently demonstrated that Siegesbeckia glabrescens(SG), a herbal medicine, induces apoptosis via nitric oxide(NO) production in human aortic smooth muscle cells(HASMCS). However, the molecular pathways involved in SG-mediated apoptosis are not fully understand. In the present study, we investigated the cellular mechanisms of SG-induced apoptosis in HASMCS. SG induced NO production through inducible nitric oxide synthase(iNOS) induction. The apoptotic effect of SG was attenuated by L-NNA, a NOS inhibitor. In the presence of L-NNA, the degradation of procaspase-3 by SG was inhibited. SG treatment induced a decrease in Bcl-2 expression but did not affect the expression of Bax. In addition, SG treatment evoked both down-regulation of PKC ${\alpha}$ and inhibition of PKC ${\alpha}$ phosphorylation. These downregulations were reversed by addition of L-NNA. It seems likely to De a downregulation of PKC${\alpha}$ due to long term treatment with PMA. Taken together, these results suggest that apoptotic effects of SG may be due to NO production via iNOS mRNA expression. Furthermore, Bcl-2 and PKC${\alpha}$ downregulation, and caspase-3 activation may be involved in the mechanisms for apoptotic effects by SG.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.6
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• pp.519-530
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• 2022

Recent research indicates that lactate promotes the switching of vascular smooth muscle cells (VSMCs) to a synthetic phenotype, which has been implicated in various vascular diseases. This study aimed to investigate the effects of lactate on the VSMC phenotype switch and the underlying mechanism. The CCK-8 method was used to assess cell viability. The microRNAs and mRNAs levels were evaluated using quantitative PCR. Targets of microRNA were predicted using online tools and confirmed using a luciferase reporter assay. We found that lactate promoted the switch of VSMCs to a synthetic phenotype, as evidenced by an increase in VSMC proliferation, mitochondrial activity, migration, and synthesis but a decrease in VSMC apoptosis. Lactate inhibited miR-23b expression in VSMCs, and miR-23b inhibited VSMC's switch to the synthetic phenotype. Lactate modulated the VSMC phenotype through downregulation of miR-23b expression, suggesting that overexpression of miR-23b using a miR-23b mimic attenuated the effects of lactate on VSMC phenotype modulation. Moreover, we discovered that SMAD family member 3 (SMAD3) was the target of miR-23b in regulating VSMC phenotype. Further findings suggested that lactate promotes VSMC switch to synthetic phenotype by targeting SMAD3 and downregulating miR-23b. These findings suggest that correcting the dysregulation of miR-23b/SMAD3 or lactate metabolism is a potential treatment for vascular diseases.

• The Korean Journal of Physiology
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• v.27 no.2
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• pp.139-150
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• 1993

We have reported that dopamine potentiates spontaneous contractions dose-dependently in guinea-pig antral circular muscle strips (Hwang et al, 1991). To clarify the underlying excitatory mechanism of dopamine on the gastric smooth muscle, the effects of dopamine on voltage-dependent $Ca^{2+}\;currents\;and\;Ca^{2+}\;-dependent\;K^+\;currents$ were observed in enzymatically dispersed guinea-pig gastric myocytes using the whole-cell voltage-clamp technique. Experiments were also done using isometric tension recording and conventional intracellular microelectrode techniques. 1) The effect of dopamine on the spontaneous contraction of antral circular muscle strips of the guinea-pig was excitatory in a dose-dependent manner, and was blocked by phentolamine, an ${\alpha}-adrenoceptor$ blocker. 2) The slow waves were not changed by dopamine. 3) The voltage-operated inward $Ca^{2+}$ current was not influenced by dopamine. 4) The $Ca^{2+}\;-dependent\;K^+$ outward current, which might reflect the changes of intracellular calcium concentration, was enhanced by dopamine. This effect was abolished by phentolamine. 5) The enhancing effect of dopamine on the $Ca^{2+}\;-dependent\;K^+$ current disappeared with heparin which is known to block the action of $InsP_3$. From these results, it is suggested that dopamine acts via $InsP_3-mediated\;Ca^{2+}$ mobilization from intracellular stores and such action potentiates the spontaneous contraction of guinea-pig gastric smooth muscle.

• The Korean Journal of Physiology
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• v.29 no.2
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• pp.233-241
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• 1995

The nonapeptide bradykinin has been shown to exhibit an array of biological activities including relaxation/contraction of various smooth muscles. In order to investigate the effects of bradykinin on the contractility and the electrical activity of antral circular muscle of guinea-pig stomach, the isometric contraction and membrane potential were recorded. Also, using standard patch clamp technique, the $Ca^{2+}-activated$ K currents were recorded to observe the change in cytosolic $Ca^{2+}$ concentration. $0.4 {\mu}M$ bradykinin induced a triphasic contractile response (transient contraction-transient relaxation-sustained contraction) and this response was unaffected by pretreatment with neural blockers (tetrodotoxin, atropine and guanethidine) or with apamin. Bradykinin induced hyperpolarization of resting membrane potential and enhanced the amplitude of slow waves and spike potentials. The enhancement of spike potentials was blocked by neural blockers. Both the bradykinin-induced contractions and changes in membrane potential were reversed by the selective $B_2$-receptor antagonist $(N{\alpha}-adamantaneacetyl-_{D}-Arg-[Hyp, Thy,_{D}-Phe]-bradykinin)$. In whole-cell patch clamp experiment, we held the membrane potential at -20 mV and spontaneous and transient changes of Ca-activated K currents were recorded. Bradykinin induced a large transient outward current, consistent with a calcium-releasing action of bradykinin front the intracellular calcium pool, because such change was blocked by pretreatment with caffeine. Bradykinin-induced contraction was also blocked by pretreatment with caffeine. From these results, it is suggested that bradykinin induces a calciumrelease and contraction through the $B_{2}$ receptor of guinea-pig gastric smooth muscle. Enhancement of slow wave activity is an indirect action of bradykinin through enteric nerve cells embedded in muscle strip.

• Parasites, Hosts and Diseases
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• v.36 no.4
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• pp.227-234
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• 1998

Actin and tropomyosin of Cryptosporidium muris were localized by immunogold labeling. Two kinds of antibodies for actin labeling were used. The polyclonal antibody to skeletal muscle (chicken back muscle) actin was labeled on the pellicle and cytoplasmic vacuoles of parasites. The feeder organelle has showed a small amount of polyclonal actin antibody labeling as well. Whereas the monoclonal antibody to smooth muscle (chicken gizzard muscle) actin was chiefly labeled on the filamentous cytoplasm of parasites. The apical portion of host gastric epithelial cell cytoplasm was also labeled by smooth muscle actin together. The polyclonal antibody to tropomyosin was much more labeled at C. muris than host cells, so it could be easily identified even with low magnification (${\times}2,000$). The tropomyosin was observed along the pellicle, cytoplasmic vacuoles, and around the nucleus also. The skeletal muscle type actin seems to play a role in various celluar functions with tropomyosin in C. muris; on the other hand, the smooth muscle type actin was located mainly on the filamentous cytoplasm and supported the parasites firm attachment to host cells. Tropomyosin on the pellicle was thought to be able to stimulate the host as a major antigen through continuous shedding out by the escape of sporozoites or merozoites from their mother cells.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.1
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• pp.37-44
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• 2017

Regulation of vascular smooth muscle cell (VSMC) phenotype plays an essential role in many cardiovascular diseases. In the present study, we provide evidence that $kr{\ddot{u}}ppel$-like factor 8 (KLF8) is essential for tumor necrosis factor ${\alpha}$ ($TNF{\alpha}$)-induced phenotypic conversion of VSMC obtained from thoracic aorta from 4-week-old SD rats. Stimulation of the contractile phenotype of VSMCs with $TNF{\alpha}$ significantly reduced the VSMC marker gene expression and KLF8. The gene expression of KLF8 was blocked by $TNF{\alpha}$ stimulation in an ERK-dependent manner. The promoter region of KLF8 contained putative Sp1, KLF4, and $NF{\kappa}B$ binding sites. Myocardin significantly enhanced the promoter activity of KLF4 and KLF8. The ectopic expression of KLF4 strongly enhanced the promoter activity of KLF8. Moreover, silencing of Akt1 significantly attenuated the promoter activity of KLF8; conversely, the overexpression of Akt1 significantly enhanced the promoter activity of KLF8. The promoter activity of SMA, $SM22{\alpha}$, and KLF8 was significantly elevated in the contractile phenotype of VSMCs. The ectopic expression of KLF8 markedly enhanced the expression of SMA and $SM22{\alpha}$ concomitant with morphological changes. The overexpression of KLF8 stimulated the promoter activity of SMA. Stimulation of VSMCs with $TNF{\alpha}$ enhanced the expression of KLF5, and the promoter activity of KLF5 was markedly suppressed by KLF8 ectopic expression. Finally, the overexpression of KLF5 suppressed the promoter activity of SMA and $SM22{\alpha}$, thereby reduced the contractility in response to the stimulation of angiotensin II. These results suggest that cross-regulation of KLF family of transcription factors plays an essential role in the VSMC phenotype.

• BMB Reports
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• v.44 no.8
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• pp.497-505
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• 2011

Reactive oxygen species (ROS), which include superoxide anions and peroxides, induce oxidative stress, contributing to the initiation and progression of cardiovascular diseases involving atherosclerosis. The endogenous and exogenous factors hypercholesterolemia, hyperglycemia, hypertension, and shear stress induce various enzyme systems such as nicotinamide adenine dinucleotide (phosphate) oxidase, xanthine oxidase, and lipoxygenase in vascular and immune cells, which generate ROS. Besides inducing oxidative stress, ROS mediate signaling pathways involved in monocyte adhesion and infiltration, platelet activation, and smooth muscle cell migration. A number of antioxidant enzymes (e.g., superoxide dismutases, catalase, glutathione peroxidases, and peroxiredoxins) regulate ROS in vascular and immune cells. Atherosclerosis results from a local imbalance between ROS production and these antioxidant enzymes. In this review, we will discuss 1) oxidative stress and atherosclerosis, 2) ROS-dependent atherogenic signaling in endothelial cells, macrophages, and vascular smooth muscle cells, 3) roles of peroxidases in atherosclerosis, and 4) antioxidant drugs and therapeutic perspectives.

• Clinical and Experimental Pediatrics
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• v.48 no.10
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• pp.1038-1049
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• 2005

Asthma is characterized by a chronic inflammatory disorder of the airways that leads to tissue injury and subsequent structural changes collectively called airway remodelling. Characteristic changes of airway remodelling in asthma include goblet cell hyperplasia, deposition of collagens in the basement membrane, increased number and size of microvessels, hypertrophy and hyperplasia of airway smooth muscle, and hypertrophy of submucosal glands. Apart from inflammatory cells, such as eosinophils, activated T cells, mast cells and macrophages, structural tissue cells such as epithelial cells, fibroblasts and smooth muscle cells can also play an important effector role through the release of a variety of mediators, cytokines, chemokines, and growth factors. Through a variety of inflammatory mediators, epithelial and mesenchymal cells cause persistence of the inflammatory infiltrate and induce airway structural remodelling. The end result of chronic airway inflammation and remodelling is an increased thickness of the airway wall, leading to a increased the bronchial hyperresponsiveness and fixed declined lung function.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.136.2-137
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• 2003

It was previously reported that luteolin, a flavone compound, displayed the potent anti-oxidant and anti-inflammatory effects, which have also been successful in reducing vascular smooth muscle cells(VSMCs) proliferation after arterial injury. Proliferation of VSMCs plays an important role in development of astherosclerosis. In this study, a possible anti-proliferative effect and its mechanism on rat aortic VSMCs by luteolin was investigated. (omitted)

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.2
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• pp.480-487
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• 2009

Atherosclerosis, slow progressing inflammatory lesion in arteries, is one of the major causes of cardiovascular diseases. As mortality due to cardiovascular disease keeps increasing in Korea, researches on pathological mechanism of atherosclerosis may be beneficial in fighting against cardiovascular diseases. It is known that migration and MMP-9 secretion of Vascular Smooth Muscle Cell(VSMC) play a significant part in pathogenesis of atherosclerosis, although detailed mechanism of entire process is not clarified. We investigated whether the seeds of Trichosanthes kirilowii maxim (TS), inhibit migration and MMP-9 production of HASMC(human aortic SMC), which were induced by TNF-${\alpha}$ treatment. Migration assay showed that TS inhibited the migration of HASMC induced by TNF-${\alpha}$, in dose dependent manner. Also by Zymography MMP-9 production of HASMC was found to be reduced by TS, both in time and in dose dependent manner. Western blotting results suggest TS suppress activity of MAPkinases.