• Proceedings of the Korean Biophysical Society Conference
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• 1997.07a
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• pp.15-15
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• 1997

Recent studies indicate that hydrogen peroxide (H$_2$O$_2$), which is one of the reactive oxygen species involved in the oxidative stress, is an intracellular secondary messenger in the signal transduction. A novel family of thiol specific antioxidant (TSA) enzymes with a peroxidase activity shows no sequence homology to previously known antioxidant enzymes.(omitted)

• The Korean Journal of Pharmacology
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• v.13 no.2
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• pp.35-39
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• 1977

Cyclic adenosine monophosphate (cAMP), known as a versatile regulator of cellular processes and as a secondary messenger of various hormones and other biogenic agents, such as prostaglandins and histamine, induced prompt and transient antidiuresis followed by mild natriuresis and diuresis, when it was administered into the lateral ventricle of the rabbit in doses ranging from $100\;{\mu}g$ to 1 mg. The initial antidiuresis was brought about by the systemic hypotension, whereas the secondary diuresis seemed to be resulted from the decreased tubular reabsorption of sodium, suggestive of participation of certain endogenous natriuretic agent. This observation suggests that cAMP might be involved in the center-mediated renal action of prostaglandins.

• Journal of Life Science
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• v.21 no.3
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• pp.473-479
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• 2011

Adenylyl cyclase (AC) catalyzes the formation of cyclic AMP (cAMP) from ATP. The cAMP produced by AC serves as a secondary messenger in a variety of signal transduction pathways, and controls various cellular functions in many organisms. ACs can be grouped into six classes based on their primary amino acid sequences. Eukaryotes and mycobacteria contain only members of class III AC. The catalytic cyclase domains of class III AC are active as dimers: mammalian ACs, which are composed of a single polypeptide with two catalytic cyclase domains, form the active site as a result of intramolecular dimerization of the catalytic cyclase domains. In contrast, mycobacterial ACs function as homodimers, since their polypeptides contain a single catalytic cyclase domain. Six amino acids are required for the catalytic activity of class III AC - two aspartate residues, a lysine-aspartate pair and an arginine-asparagine pair. 16 ACs belonging to the class III were identified in Mycobacterium tuberculosis H37Rv, and their characteristics are reviewed.

• Childhood Kidney Diseases
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• v.26 no.2
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• pp.97-100
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• 2022

In response to the global coronavirus disease 2019 (COVID-19) pandemic, vaccines were developed and approved quickly. However, numerous cardiovascular adverse events have been reported. We present two adolescent cases who developed a hypertensive crisis following NT162b2 mRNA COVID-19 vaccination. Patient 1 was an 18-year-old male and his systolic blood pressure was 230 mmHg one day after the second vaccine. He was obese. No secondary cause of hypertension other than the vaccine was identified. Patient 2 was an 18-year-old male who complained with palpitation after the first vaccine. His blood pressure was 178/109 mmHg. He had autosomal dominant polycystic kidney disease. Both were treated with continuous infusion of labetalol followed by losartan, and blood pressure was controlled. Patient 2 received second vaccination and his blood pressure did not rise. It is warranted to measure blood pressure in adolescents at high risk of hypertension after NT162b2 mRNA COVID-19 vaccination.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.895-901
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• 2013

Resistance to induction of apoptosis is a major obstacle for bladder cancer treatment. Bcl-2 is thought to be involved in anti-apoptotic signaling. In this study, we investigated the effect of Bcl-2 overexpression on apoptotic resistance and intracellular reactive oxygen species (ROS) generation in bladder cancer cells. A stable Bcl-2 overexpression cell line, BIU87-Bcl-2, was constructed from human bladder cancer cell line BIU87 by transfecting recombinant Bcl-2 [pcDNA3.1(+)-Bcl-2]. The sensitivity of transfected cells to adriamycin (ADR) was assessed by MTT assay. Apoptosis was examined by flow cytometry and acridine orange fluorescence staining. Intracellular ROS was determined using flow cytometry, and the activities of superoxide dismutase (SOD) and catalase (CAT) were also investigated by the xanthinoxidase and visible radiation methods using SOD and CAT detection kits. The susceptibility of BIU87-Bcl-2 cells to ADR treatment was significantly decreased as compared with control BIU87 cells. Enhanced expression of Bcl-2 inhibited intracellular ROS generation following ADR treatment. Moreover, the suppression of SOD and CAT activity induced by ADR treatment was blocked in the BIU87-Bcl-2 case but not in their parental cells. The overexpression of Bcl-2 renders human bladder cancer cells resistant to ADR-induced apoptosis and ROS might act as an important secondary messenger in this process.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.81-81
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• 2018

The present study was investigated on in vitro anti-obesity effect of 4-hydroxybenzyl alcohol from Cudrania tricuspidata. We isolated various compounds from Cudrania tricuspidata. Among these compounds, anti-obesity effects of 4-hydroxybenzyl alcohol was examined by lipase activity assay, cyclic adenosine monophosphate (cAMP)-specific phosphodiesterase type IV (PDE4) activity assay, and citrate synthase activity assay. 4-hydroxybenzyl alcohol and Cudrania tricuspidata extracts inhibited the enzymatic activities of lipase, PDE4, and citrate synthase. Lipase is known to mediate the hydrolysis of triacylglycerol in adipose tissue and cholesterol esters in other tissue or cells. Also, PDE4 hydrolyses cAMP, a crucial secondary messenger for in metabolic pathways including glucose and lipid metabolism, lipolysis, and thermogenic function. 4-hydroxybenzyl alcohol and Cudrania tricuspidata extracts induced the inhibitory effect against each enzymatic activity on several specific substrates as observed by detection at 405 or 412 nm. These findings might be attributable to the inhibition of adipogenesis, and partial prevention of obesity. In conclusion, these results show that 4-hydroxybenzyl alcohol and Cudrania tricuspidata may be a critical candidate as a natural anti-obesity source.

• Journal of Korean Neurosurgical Society
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• v.48 no.1
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• pp.1-7
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• 2010

Objective : Notochordal cells in the intervertebral disc interact with nucleus pulposus (NP) cells and support the maintenance of disc homeostasis by regulation of matrix production. However, the influence of notochordal cells has not been evaluated in the annulus fibrosus (AF), which is the primary pain generator in the disc. We hypothesized that the notochordal cell has the capacity to modulate inflammatory mediators secreted by AF cells secondary to stimulation. Methods : Notochordal and AF cells were isolated from adult New Zealand white rabbits. AF pellets were cultured with notochordal cell clusters or in notochordal cell-conditioned media (NCCM) for 24 or 48 hours with proinflammatory cytokines at varying concentrations. Gene expression in AF pellets were assayed for nitric oxide synthase (iNOS), cyclo-oxygenase (COX)-2, and interleukin (IL)-6 by real time reverse transcriptase polymerase chain reaction (RT-PCR). Results : AF pellet in NCCM significantly decreased the iNOS and COX-2 messenger ribonucleic acid (mRNA) levels compared to AF pellets alone and AF pellets with notochordal cells (p < 0.05). AF pellet resulted in dose-dependent iNOS and COX-2 expression in response to IL-$1{\beta}$, stimulation, demonstrating that 1 ng/ml for 24 hours yielded a maximal response. AF pellet in NCCM significantly decreased the expression of iNOS and COX-2 in response to 1ng/ml IL-$1{\beta}$, stimulation at 24 hours (p < 0.05). There was no difference in IL-6 expression compared to AF pellets alone or AF pellets with notochordal cell clusters. Conclusion : We conclude that soluble factors from notochordal cells mitigate the gene expression of inflammatory mediators in stimulated AF, as expected after annular injury, suggesting that notochordal cells could serve as a novel therapeutic approach in symptomatic disc development.

• Journal of Life Science
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• v.24 no.12
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• pp.1378-1382
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• 2014

Phospholipase D (PLD) catalyzes the hydrolysis of phospholipid to phosphatidic acid (PA), a lipid secondary messenger. Two forms of PLD isozymes, phosphatidylcholine-specific PLD1 and PLD2, have been identified. PLD has emerged as a critical regulator of cell proliferation and survival signaling, and dysregulation of PLD occurs in a various illnesses, including cancer. PLD activity is essential for cell survival and protection from apoptosis. Overexpression of PLD isozymes or PLD-generated PA attenuates the expression of apoptotic genes and confers resistance to apoptosis. The apoptosis-related molecular mechanisms of PLD remain largely unknown. Recently, the dynamics of PLD turnover during apoptosis have been reported. The cleavage of PLD isozymes as specific substrates of caspase differentially regulates apoptosis. PLD1 is cleaved at one internal site, and PLD2 is cleaved two sites at the front of the N-terminus. The cleavage of PLD1 reduces its enzymatic activity, probably via the dissociation of two catalytic motifs, whereas the cleavage of PLD2 does not affect the catalytic motifs and its activity. Thus, PLD2 maintains antiapoptotic capacity, despite its cleavage. Therefore, the differential cleavage pattern of PLD isozymes by caspase affects its enzymatic activity and antiapoptotic function. Thus, PLD is considered a potential target for cancer therapy. We summarize recent studies regarding the functional role of PLD in apoptosis.

• Natural Product Sciences
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• v.23 no.1
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• pp.35-39
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• 2017

D-chiro-inositol (DCI) is a secondary messenger in insulin signal transduction. It is produced in vivo from myo-inositol via action of epimerase. In this study, we evaluated antitumor activity of DCI against human breast cancer both in vitro and in vivo. In order to determine the inhibitory effects of DCI on growth of human breast cancer cells (MDA-MB-231), two different assessment methods were implemented: MTT assay and mouse xenograft assay. MTT assay demonstrated downturn in cell proliferation by DCI treatment (1, 5, 10, 20 and 40 mM) groups by 18.3% (p < 0.05), 17.2% (p < 0.05), 17.5% (p < 0.05), 18.4% (p < 0.05), and 24.9% (p < 0.01), respectively. Also, inhibition of tumor growth was investigated in mouse xenograft model. DCI was administered orally at the dose of 500 mg/kg and 1000 mg/kg body weight to treat nude mouse for 45 consecutive days. On the 45th day, tumor growth of DCI (500 mg/kg and 1000 mg/kg) groups was suppressed by 22.1% and 67.6% as mean tumor volumes were $9313.8{\pm}474.1mm^3$ and $3879.1{\pm}1044.1mm^3$, respectively. Furthermore, breast cancer stem cell (CSC) phenotype ($CD44^+/C24^-$) was measured using flow cytometry. On the 46th day, CSC ratios of DCI (500 mg/kg) and co-treatment with doxorubicin (4 mg/kg) and DCI (500 mg/kg) group decreased by 24.7% and 53.9% (p < 0.01), respectively. Finally, from tumor recurrence assay, delay of 5 days in the co-treatment group compared to doxorubicin (4 mg/kg) alone group was observed. Based on these findings, we propose that DCI holds potential as an anti-cancer drug for treatment of breast cancer.

• Archives of Pharmacal Research
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• v.24 no.6
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• pp.607-612
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• 2001

Endogenous carbon monoxide (CO) shares with nitric oxide (NO) a role as a putative neural messenger in the brain. Both gases are believed to modulate CNS function via an increase in cytoplasmic cGMP concentrations secondary to the activation of soluble guanylate cyclase (sGC). Recently CO and NO were proposed as a possible mediator of febrile response in hypothalamus. NO has been reported to activate both the constitutive and inducible isoform of the cyclooxygenase (COX). Thus, we investigated whether CO arising from heme catabolism by heme oxygenate (HO) is involved in the febrile response via the activation of COX in the hypothalamus. $PGE_2$ which is a final mediator of febrile response released from primary cultured hypothalamic cells was taken as a marker of COX activity. $PGE_2$ concentration was measured with EIA kits. Exogenous CO (CO-saturated medium) and hemin (a substrate and potent inducer of HO) evoked an increase in $PGE_2$ release from hypothalamic cells, and these effects were blocked by methylene blue (an inhibitor of sGC). And membrane permeable cGMP analogue, dibutyryl-cGMP elicited significant increases in $PGE_2$release. These results suggest that there may be a functional link between HO and COX enzymatic activities. The gaseous product of hemin through the HO pathway, CO, might play a role through the modulation of the COX activity in the hypothalamus.