• Journal of Microbiology and Biotechnology
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• 제24권2호
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• pp.160-167
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• 2014

Oligopeptidase B (OpdB) is a serine peptidase widespread among bacteria and protozoa that has emerged as a virulence factor despite its function has not yet been precisely established. By using an OpdB-overexpressing Escherichia coli strain, we found that the overexpressed peptidase makes the bacterial cells specifically less susceptible to several proline-rich antimicrobial peptides known to penetrate into the bacterial cytosol, and that its level of activity directly correlates with the degree of resistance. We established that E. coli OpdB can efficiently hydrolyze in vitro cationic antimicrobial peptides up to 30 residues in length, even though they contained several prolines, shortening them to inactive fragments. Two consecutive basic residues are a preferred cleavage site for the peptidase. In the case of a single basic residue, there is no cleavage if proline residues are present in the $P_1$ and $P_2$ positions. These results also indicate that cytosolic peptidases may cause resistance to antimicrobial peptides that have an intracellular mechanism of action, such as the proline-rich peptides, and may contribute to define the substrate specificity of the E. coli OpdB.

• The Korean Journal of Physiology and Pharmacology
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• 제22권6호
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• pp.679-688
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• 2018

Autism spectrum disorders (ASDs) are neurodevelopmental disorders that share behavioral features, the results of numerous studies have suggested that the underlying causes of ASDs are multifactorial. Behavioral and/or neurobiological analyses of ASDs have been performed extensively using a valid model of prenatal exposure to valproic acid (VPA). Abnormal synapse formation resulting from altered neurite outgrowth in neural progenitor cells (NPCs) during embryonic brain development has been observed in both the VPA model and ASD subjects. Although several mechanisms have been suggested, the actual mechanism underlying enhanced neurite outgrowth remains unclear. In this study, we found that VPA enhanced the expression of brain-derived neurotrophic factor (BDNF), particularly mature BDNF (mBDNF), through dual mechanisms. VPA increased the mRNA and protein expression of BDNF by suppressing the nuclear expression of methyl-CpG-binding protein 2 (MeCP2), which is a transcriptional repressor of BDNF. In addition, VPA promoted the expression and activity of the tissue plasminogen activator (tPA), which induces BDNF maturation through proteolytic cleavage. Trichostatin A and sodium butyrate also enhanced tPA activity, but tPA activity was not induced by valpromide, which is a VPA analog that does not induce histone acetylation, indicating that histone acetylation activity was required for tPA regulation. VPA-mediated regulation of BDNF, MeCP2, and tPA was not observed in astrocytes or neurons. Therefore, these results suggested that VPA-induced mBDNF upregulation was associated with the dysregulation of MeCP2 and tPA in developing cortical NPCs.

• Asian-Australasian Journal of Animal Sciences
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• 제33권3호
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• pp.373-381
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• 2020

There is a need for newer feed additives due to legal prohibition on inclusion of growth promoting antibiotics in livestock diets in several countries due to antimicrobial resistance. In this context, rare earth elements (REE) have gained attention among animal nutritionists as potential growth promoters. Currently, several studies have reported better weight gain, milk production, egg laying capacity and feed conversion efficiency among different breeds of farm animals following supplementation with REE, with however largely inconsistent results. Furthermore, REE supplementation has also shown to improve ruminal fibrolytic and proteolytic activities as well as flavor of meat with negligible residues in edible tissue, however the mechanism behind this action is still unclear. According to existing research, due to their poor absorption and similarity with calcium REE might exert their action locally on gut microbial populations within the gastrointestinal tract (GIT). Moreover, REE have also shown anti-inflammatory, anti-oxidative as well as immune stimulating effects. The present review aims to broaden the knowledge about use of REE as feed additives for livestock and sum up efficacy of REE supplementation on performance and health of animals by comparing the findings. Till date, researches with REE have shown properties that make them a promising, new and safe alternative feed additive but further exploration is recommended to optimize effects and clarify discrepancy of various results before practical proposals can be drafted.

• Journal of Microbiology and Biotechnology
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• 제25권3호
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• pp.334-342
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• 2015

4-O-Methylhonokiol (MH), a bioactive compound derived from Magnolia officinalis, is known to exhibit antitumor effects in various cancer cells. However, the precise mechanism of its anticancer activity in cervical cancer cells has not yet been studied. In this study, we demonstrated that MH induces apoptosis in SiHa cervical cancer cells by enhancing peroxisome proliferator-activated receptor-gamma (PPARγ) activation, followed by inhibition of the PI3K/Akt pathway and intrinsic pathway induction. MH upregulated PPARγ and PTEN expression levels while it decreased p-Akt in the MH-induced apoptotic process, thereby supporting the fact that MH is a PPARγ activator. Additionally, MH decreased the expression of Bcl-2 and Bcl-XL, inducing the intrinsic pathway in MH-treated SiHa cells. Furthermore, MH treatment led to the activation of caspase-3/caspase-9 and proteolytic cleavage of polyADP ribose polymerase. The expression levels of Fas (CD95) and E6/E7 oncogenes were not altered by MH treatment. Taken together, MH activates PPARγ/PTEN expression and induces apoptosis via suppression of the PI3K/Akt pathway and mitochondria-dependent pathways in SiHa cells. These findings suggest that MH has potential for development as a therapeutic agent for human cervical cancer.

• 한국수산과학회지
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• 제46권4호
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• pp.384-392
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• 2013

An ethanolic extract of Undaria pinnatifida was fractionated using several solvents. Of the fractions, the ethyl acetate fraction had the greatest inhibitory effect on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 macrophage cells. Using this fraction (U. pinnatifida ethyl acetate extract, UPE), we investigated the molecular mechanism underlying its inhibitory effect on LPS-stimulated RAW 264.7 cells. Pretreatment of the cells with up to $100{\mu}g/mL$ UPE significantly inhibited NO production and inducible nitric oxide synthase (iNOS) expression, in a dose-dependent manner. Similarly, UPE treatment markedly reduced the production of pro-inflammatory cytokines, such as interleukin (IL)-1, IL-6 and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), while it strongly suppressed the nuclear translocation of nuclear factor-kappa B (NF-${\kappa}B$) by preventing proteolytic degradation of inhibitor of nuclear factor ${\kappa}B$ $(I{\kappa}B)-{\alpha}$. Moreover, UPE treatment significantly reduced the phosphorylation of phosphatidylinositol 3-kinase (PI3K)/Akt and mitogen-activated protein kinase (MAPK) in LPS-stimulated cells. These results indicate that UPE contains anti-inflammatory compounds and suggest that it might be used as a functional food material that assists in prevention of inflammatory diseases.

• International Journal of Oral Biology
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• 제45권3호
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• pp.99-106
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• 2020

Ficus carica L. (fig) is one of the first cultivated crops and is as old as humans. This plant has been extensively used as a traditional medicine for treating diseases, such as cough, indigestion, nutritional anemia, and tuberculosis. However, the physiological activity of fig leaves on oral cancer is as yet unknown. In this study, we investigated the anticancer effect of methanol extracts of Ficus carica (MeFC) and the mechanism of cell death in human FaDu hypopharyngeal squamous carcinoma cells. MeFC decreased the viability of oral cancer (FaDu) cells but did not affect the viability of normal (L929) cells, as determined by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay and Live and Dead assay. In addition, MeFC induced apoptosis through the proteolytic cleavage of procaspase-3, -9, poly (ADP-ribose) polymerase (PARP), downregulation of Bcl-2, and upregulation of Bax, as determined by 4′,6-diamidino-2-phenylindole dihydrochloride staining and western blot analysis. Moreover, a concentration of MeFC without cytotoxicity (0.25 mg/mL) significantly suppressed colony formation, a hallmark of cancer development, and completely inhibited the colony formation at 1 mg/mL. Collectively, these results suggest that MeFC exhibits a potent anticancer effect by suppressing the growth of oral cancer cells and colony formation via caspase- and mitochondrial-dependent apoptotic pathways in FaDu human hypopharyngeal squamous carcinoma cells. Therefore, the methanol extract of Ficus carcica leaves provide a natural chemotherapeutic drug for human oral cancer.

• International Journal of Oral Biology
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• 제41권4호
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• pp.163-173
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• 2016

Flavonoid myricetin, usually found in tea and medicinal plants, has antioxidant and anti-inflammatory effects. Our objectives in this study were to verify the effects of myricetin on periodontal ligament fibroblasts (PDLFs) under inflammatory conditions and to observe its effects on osteoclast generation and on cytokine expression in RAW264.7 cells. To determine the effects of myricetin on PDLFs, we examined the expression and activity of proteolytic enzymes, including MMP-1, MMP-2, and MMP-8, which all play an important role in chronic periodontitis. We observed the effects of myricetin on intracellular signal transduction to verify the molecular mechanism involved. By measuring the formation of TRAP-positive multinucleated cells and the expression and activity of MMP-8, we were able to assess the effects of myricetin on osteoclast generation. In addition, by measuring the secretion of IL-6 and NO, we could evaluate the effects of myricetin on inflammatory mediators. We found that Myricetin had no effect on the viability of the PDLFs in the presence of inflammation, but it did decrease both the expression of MMP-1 and MMP-8 and the enzyme activity of MMP-2 and MMP-8 in these fibroblasts. Myricetin also decreased the lipopolysaccharide-stimulated phosphorylation of JNK, p38 signaling, IKKB, AKT, and p65RelA in the PDLFs. In the RAW264.7 cells, myricetin inhibited both the expression and the activity of MMP-8. Furthermore, Myricetin not only suppressed the generation of LPS-stimulated osteoclasts, but it also slightly inhibited LPS-stimulated degradation of IkB and decreased the release of LPS-induced IL-6 and NO. These findings suggest that myricetin alleviates the tissue-destructive processes that occur during periodontal inflammation.

• 약학회지
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• 제41권2호
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• pp.247-254
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• 1997

The proteinase-activated receptor (PAR-2) belongs to the family of seven transmembrane region receptors, like the thrombin receptor, it is activated by specific proteolytic clea vage of its extracellular amino terminus and a synthetic peptide (SLIGRL). The earthworm protein fraction (EPF) extracted from Lumbricus rubellus elicted dose- and endothelium-dependent relaxations in phenylephrine-contracted rat thoracic aorta, whereas heat inactivated EPF (0.5 ${\mu}g$ /ml) had no effect. In the presence of the nitric oxide synthase inhibitor NG-methyl-L-arginine (1.8 micro M), EPF (0.5 ${\mu}g$ /ml)-induced relaxations were partially inhibited. Furthermore, EPF (0.5 ${\mu}g$ /ml) dramatically caused relaxation of thrombin-desenstized rat thoracic aorta. These results indicate that EPF activates PAR-2 in vascular endothelial cell. Intravenous injection of EPF (20 mg/kg, bolus) into anesthetized rats produced a marked depressor response. EPF (0 ~ 80 ${\mu}g$ /ml, gradient) was very effective on increasing of perfusion volume in rabbit ear vessel preparations. These results imply the usefulness of EPF as a vascular smooth muscle relaxant and indicate that the activation of PAR-2 may be a mechanism of EPF on hemokinetic improvement.

• 한국축산식품학회지
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• 제40권2호
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• pp.274-285
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• 2020

In this study, ovalbumin (OVA) hydrolysates were prepared using various proteolytic enzymes and the anti-inflammatory activities of the hydrolysates were determined. Also, the potential application of OVA as a functional food material was discussed. The effect of OVA hydrolysates on the inhibition of nitric oxide (NO) production was evaluated via the Griess reaction, and their effects on the expression of inducible NO synthase (inducible nitric oxide synthase, iNOS) were assessed using the quantitative real-time PCR and Western blotting. To determine the mechanism by which OVA hydrolysates activate macrophages, pathways associated with the mitogen-activated protein kinase (MAPK) signaling were evaluated. When the OVA hydrolysates were added to RAW 264.7 cells without lipopolysaccharide (LPS) stimulation, they did not affect the production of NO. However, both the OVA-Protex 6L hydrolysate (OHPT) and OVA-trypsin hydrolysate (OHT) inhibited NO production dose-dependently in LPS-stimulated RAW 264.7 cells. Especially, OHT showed a strong NO-inhibitory activity (62.35% at 2 mg/mL) and suppressed iNOS production and the mRNA expression for iNOS (p<0.05). Also, OHT treatment decreased the phosphorylation levels of Jun amino-terminal kinases (JNK) and extracellular signal-regulated kinases (ERK) in the MAPK signaling pathway. These findings suggested that OVA hydrolysates could be used as an anti-inflammatory agent that prevent the overproduction of NO.

• International Journal of Oral Biology
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• 제43권2호
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• pp.61-68
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• 2018

Codium fragile (Suringar) Hariot is an edible green seaweed that belong to the Codiaceae family and has been used in Oriental medicine for the treatment of enterobiasis, dropsy, and dysuria. Methanol extract of codium fragile has anti-oxidant, anti-inflammatory and anti-cancer properties, although the anti-cancer effect on oral cancer has not yet been reported. In this study, we investigated the anti-cancer activity and the mechanism of cell death by methanol extracts of Codium fragile (MeCF) on human FaDu hypopharyngeal squamous carcinoma cells. Our data showed that MeCF inhibits cell viability in a dose-dependent manner, and markedly induced apoptosis, as determined by the MTT assay, Live/Dead assay, and DAPI stain. In addition, MeCF induced the proteolytic cleavage of procaspase -3, -7, -9 and poly(ADP-ribose) polymerase(PARP), and upregulated or downregulated the expression of mitochondrial-apoptosis factor, Bax(pro-apoptotic factor), and Bcl-2(anti-apoptotic factor). Futhermore, MeCF induced a cell cycle arrest at the G1/S phase through suppressing the expression of the cell cycle cascade proteins, p21, CDK4, CyclinD1, and phospho-Rb. Taken together, these results indicated that MeCF inhibits cell growth, and this inhibition is mediated by caspase- and mitochondrial-dependent apoptotic pathways through cell cycle arrest at the G1/S phase in human FaDu hypopharyngeal squamous carcinoma cells. Therefore, methanol extracts of Codium fragile can be provided as a novel chemotherapeutic drug due to its growth inhibition effects and induction of apoptosis in human oral cancer cells.