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Background and Purpose: Dieckol is a phlorotannin that can be found in seaweeds, particularly in Eisenia bicyclis (brown algae) and is known to have anti-oxidant, anti-inflammatory, and anti-microbial properties. It also possesses anti-thrombotic and pro-fibrinolytic activities; however, the mechanistic aspects of anti-platelet and anti-thrombotic activity are yet to be explored., Study Design and Methodology: We investigated the pharmacological effects of dieckol on the modulation of platelet functions using human, rat, and mice models. Inhibitory effects of dieckol on platelet aggregation were assessed using platelet-rich plasma and washed platelets, followed by measurement of dense granule secretions, fibrinogen binding to integrin α IIb β 3 , fibronectin adhesion assay, platelet spreading on immobilized fibrinogen, and clot retraction. Cyclic nucleotide signaling events were evaluated, such as cyclic-AMP production followed by vasodilator-stimulated phosphoprotein (VASP) stimulation. The in vivo anti-thrombotic potential was evaluated in mice using an acute pulmonary thromboembolism model and tail bleeding assay., Results: Dieckol markedly inhibited platelet aggregation and granule secretion; furthermore, it down-regulated integrin α IIb β 3 -mediated inside-out and outside-in signaling events, including platelet adhesion, spreading, and clot retraction, whereas it upregulated the cAMP-PKA-VASP pathway. Dieckol-treated mice significantly survived the thrombosis than vehicle treated mice, without affecting hemostasis. Histological examinations of lungs revealed minimum occluded vasculature in dieckol-treated mice., Conclusion: Dieckol possesses strong anti-platelet and anti-thrombotic properties and is a potential therapeutic drug candidate to treat and prevent platelet-related cardiovascular disorders., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Allelic diversity leading to multiple gene polymorphisms of vivax malaria parasites has been shown to greatly contribute to antigenic variation and drug resistance, increasing the potential for multiple-clone infections within the host. Therefore, to identify multiple-clone infections and the predominant haplotype of Plasmodium vivax in a South Korean population, P. vivax merozoite surface protein-1 (PvMSP-1) was analyzed by pyrosequencing. Pyrosequencing of 156 vivax malaria-infected samples yielded 97 (62.18%) output pyrograms showing two main types of peak patterns of the dimorphic allele for threonine and alanine (T1476A). Most of the samples evaluated (88.66%) carried multiple-clone infections (wild- and mutant-types), whereas 11.34% of the same population carried only the mutant-type (1476A). In addition, each allele showed a high frequency of guanine (G) base substitution at both the first and third positions (86.07% and 81.13%, respectively) of the nucleotide combinations. Pyrosequencing of the PvMSP-1 42-kDa fragment revealed a heterogeneous parasite population, with the mutant-type dominant compared to the wild-type. Understanding the genetic diversity and multiple-clone infection rates may lead to improvements in vivax malaria prevention and strategic control plans. Further studies are needed to improve the efficacy of the pyrosequencing assay with large sample sizes and additional nucleotide positions., (Copyright © 2017 Elsevier B.V. All rights reserved.)

In this study, the status of Anaplasma phagocytophilum infection was assessed in shelter dogs in Seoul, Korea, with PCR and phylogenetic analyses. Nested PCR on 1058 collected blood samples revealed only one A. phagocytophilum positive sample (female, age <1year, mixed breed, collected from the north of the Han River). The genetic variability of A. phagocytophilum was evaluated by genotyping, using the 16S rRNA, groEL, and msp2 gene sequences of the positive sample. BLASTn analysis revealed that the 16S rRNA, groEL, and msp2 genes had 99.6%, 99.9%, and 100% identity with the following sequences deposited in GenBank: a cat 16S rRNA sequence from Korea (KR021166), a rat groEL sequence from Korea (KT220194), and a water deer msp2 sequence from Korea (HM752099), respectively. Phylogenetic analyses classified the groEL gene into two distinct groups (serine and alanine), whereas the msp2 gene showed a general classification into two groups (USA and Europe) that were further subgrouped according to region. To the best of our knowledge, this study is the first to describe the molecular diagnosis of A. phagocytophilum in dogs reared in Korea. In addition, the high genetic identity of the 16S rRNA and groEL sequences between humans and dogs from the same region suggests a possible epidemiological relation. Given the conditions of climate change, tick ecology, and recent incidence of human granulocytic anaplasmosis in Korea, the findings of this study underscore the need to establish appropriate control programs for tick-borne diseases in Korea., (Copyright © 2016 Elsevier GmbH. All rights reserved.)

This study investigated the seroprevalence of Toxoplasma gondii in cattle in Gyeongbuk province, the largest producer of cattle in Korea. Of blood samples obtained from 568 animals, 0.5% (3 of 568) tested seropositive for T. gondii by using a commercial ELISA kit. Among young individuals (≤1 year old), adult individuals (2 years old), and old individuals (≥3 years old), 0 (0%) of 37, 3 (0.6%) of 474, and 0 (0%) of 57 were seropositive, respectively. Among male, female, and castrated individuals, 0 (0%) of 22, 0 (0%) of 74, and 3 (0.6%) of 472 were seropositive, respectively. Among individuals from east, south, and northwest regions of Gyeongbuk province, 0 (0%) of 155, 2 (0.7%) of 288, and 1 (0.8%) of 125 were seropositive, respectively. No statistical differences were observed among the groups. Although a low T. gondii seroprevalence was detected in cattle raised in Gyeongbuk province, toxoplasmosis is still a concern owing to the Korean habit of eating raw or undercooked meat and the consequent risk of Toxoplasma transmission to animals and humans.

Quercetin is a major bioflavonoid widely present in fruits and vegetables. It exhibits anti-inflammatory, anti-tumor, antioxidant properties and reduces cardiovascular disease risks. However, the molecular mechanism of action against inflammation in RAW 264.7 cells is only partially explored. Quercetin effect on LPS-induced gene and protein expressions of inflammatory mediators and cytokines were determined. Moreover, involvement of heme-oxygenase-1, protein kinases, adaptor proteins and transcription factors in molecular mechanism of quercetin action against inflammation were examined. Quercetin inhibited LPS-induced NO, PGE₂, iNOS, COX-2, TNF-α, IL-1β, IL-6 and GM-CSF mRNA and protein expressions while it promoted HO-1 induction in a dose- and time-dependent manner. It also suppressed I-κB-phosphorylation, NF-κB translocation, AP-1 and NF-κB-DNA-binding and reporter gene transcription. Quercetin attenuated p38(MAPK) and JNK1/2 but not ERK1/2 activations and this effect was further confirmed by SB203580 and SP600125-mediated suppressions of HO-1, iNOS, and COX-2 protein expressions. Moreover, quercetin arrested Src, PI3K, PDK1 and Akt activation in a time- and dose-dependent manner, which was comparable to PP2 and LY294002 inhibition of Src, PI3K/Akt and iNOS expressions. Quercetin further arrested Src and Syk tyrosine phosphorylations and their kinase activities followed by inhibition of PI3K tyrosine phosphorylation. Moreover, quercetin disrupted LPS-induced p85 association to TLR4/MyD88 complex and it then limited activation of IRAK1, TRAF6 and TAK1 with a subsequent reduction in p38 and JNK activations, and suppression in IKKα/β-mediated I-κB phosphorylation. Quercetin limits LPS-induced inflammation via inhibition of Src- and Syk-mediated PI3K-(p85) tyrosine phosphorylation and subsequent TLR4/MyD88/PI3K complex formation that limits activation of downstream signaling pathways., (Copyright © 2013 Elsevier GmbH. All rights reserved.)

Melanoma is an intractable tumor that has shown very impressive and promising response to local administration of high dose recombinant TNF-alpha in combination with IFN-gamma in clinical studies. In this study, we investigated the effect of IL-6/sIL-6R on TNF-alpha-resistant B16/F10.9 melanoma cells. A low dose of TNF-alpha or IL-6/sIL-6R had minimal affect on the cell growth. However, the highly active fusion protein of sIL-6R and IL-6 (IL6RIL6), covalently linked by a flexible peptide, sensitized TNF-alpha-resistant F10.9 melanoma cells to TNF-alpha-induced apoptosis. Stimulation of the cells with IL6RIL6 plus TNF-alpha resulted in both the activation of caspase-3 and the reduction of bcl-2 expression. Flow cytometry analysis showed that IL6RIL6-upregulated TNF-R55 and TNF-R75 expression, suggesting an increase in TNF-alpha responsiveness by IL6RIL6 resulting from the induction of TNF receptors. Moreover, exposure of F10.9 cells to neutralizing antibody to TNF-R55 significantly inhibited IL6RIL6/TNF-alpha-induced cytotoxicity. These results suggest that the IL6/sIL6R/gp130 system, which sensitizes TNF-alpha-resistant melanoma cells to TNF-alpha-induced apoptosis, may provide a new target for immunotherapy.

Curcumin has been shown to exhibit anti-inflammatory, antimutagenic, and anticarcinogenic activities. However, the modulatory effect of curcumin on the functional activation of primary microglial cells, brain mononuclear phagocytes causing the neuronal damage, largely remains unknown. The current study examined whether curcumin influenced NO production in rat primary microglia and investigated its underlying signaling pathways. Curcumin decreased NO production in LPS-stimulated microglial cells in a dose-dependent manner, with an IC(50) value of 3.7 microM. It also suppressed both mRNA and protein levels of inducible nitric oxide synthase (iNOS), indicating that this drug may affect iNOS gene expression process. Indeed, curcumin altered biochemical patterns induced by LPS such as phosphorylation of all mitogen-activated protein kinases (MAPKs), and DNA binding activities of nuclear factor-kappaB (NF-kappaB) and activator protein (AP)-1, assessed by reporter gene assay. By analysis of inhibitory features of specific MAPK inhibitors, a series of signaling cascades including c-Jun N-terminal kinase (JNK), p38 and NF-kappaB was found to play a critical role in curcumin-mediated NO inhibition in microglial cells. The current results suggest that curcumin is a promising agent for the prevention and treatment of both NO and microglial cell-mediated neurodegenerative disorders.

Regulators of G protein signaling (RGSs) are inducibly expressed in response to various stimuli and the up-regulation of RGSs leads to significant decreases in GPCR responsiveness. Isoproterenol, an adrenergic receptor agonist, stimulated RGS2 mRNA in C6 rat astrocytoma cells. The up-regulation of RGS2 mRNA was abrogated by genistein, a protein tyrosine kinase inhibitor (PTK), and by broad-spectrum protein kinase C (PKC) inhibitors (staurosporine and GF109203X). alpha-Adrenergic antagonist (prazocin), beta-adrenergic antagonist (prazocin), and pertussis toxin only partially blocked the RGS2 up-regulation, suggesting that the RGS2 up-regulation is concomitantly mediated by Galphai, Galphas, and Galphaq. It is interesting to note that SB203580, a potent p38 mitogen-activated protein kinase (MAPK) inhibitor, completely inhibited the isoproterenol-mediated RGS2 expression. In addition, isoproterenol also markedly stimulated RGS2 mRNA in rat primary astrocytes, which were sensitive to SB203580 and staurosporine. Therefore, our data suggest that adrenergic receptor-mediated signaling (induced by isoproterenol) may be involved in the regulation of RGS2 expression in astrocytes via activating PTK, PKC, and p38 MAPK.

Cynaropicrin is a sesquiterpene lactone displaying immunomodulatory effects on the production of cytokine and nitric oxide from macrophages/monocytes. In this study we have examined inhibitory effect of cynaropicrin on activation of major adhesion molecules [CD29 (beta1 integrins), CD43, and CD98] on the cells assessed by U937 (promonocytic cells) homotypic aggregation. Cynaropicrin potently blocked CD29 (beta1 integrins)- and CD98-induced homotypic aggregation with IC(50) values of 3.46 and 2.98 microM, respectively, without displaying cytotoxicity. Similarly, flow cytometric analysis exhibited that cynaropicrin down-regulated strikingly surface level of CD29 and CD147, a functional regulator of CD98, but not CD43. More importantly, cynaropicrin inhibition was linked to blockade of extracellular signal-related kinase (ERK) activation and distinct from other enzyme inhibitors including rottlerin, propranolol, forskolin, and chloroquine, but not cytochalasin B. Therefore, our finding is the first demonstration that cynaropicrin may be a potent functional regulator of CD29 and CD98 via interrupting ERK activation which may be linked to cytoskeleton rearrangement, suggesting further application to CD29- and CD98-mediated diseases such as virus-induced chronic inflammation, and invasion, migration, and metastasis of leukocyte cancer cells.