• Biomedical Science Letters
• /
• v.13 no.2
• /
• pp.119-125
• /
• 2007

It is widely known that protein tyrosine kinases (PTKs) are involved in controlling many biological processes such as cell growth, differentiation, proliferation, survival and apoptosis. An $\alpha3\beta4$ subunit combination acts as a major functional acetylcholine receptor (nAChRs) in male rat major pelvic ganglion (MPG) neurons, and their activation induces fast inward currents and intracellular calcium increases. Recently it has been reported that the activity of acetylcholine receptors (AChRs) in some neurons can be negatively regulated by PTKs. However, the exact mechanism of regulation of nAChRs by PTKs is poorly understood. Therefore, we examined the potential role particular in nAChR by PTK using electrophysiology and calcium imaging in male rat MPG neurons. ACh induced inward currents and $(Ca^{2+})_i$ increases in MPG neurons, concomitantly. These responses were inhibited by more than 90% in $Na^+$- or $Ca^{2+}$- free solution. $\alpha$-conotoxin AuIB, a selective $\alpha3\beta4$ nAChR blocket, inhibited ACh-induced inward currents. Genistein (10 $\mu$M), a broad-spectrum tyrosine kinase inhibitor, markedly decreased ACh-induced currents and $Ca^{2+}$ transients, whereas 10 $\mu$M genistin, an inactive analogue, had little effect. Overall these data suggest that the activities of $\alpha3\beta4$ AChRs in MPG neurons are positively regulated by PTK. In conclusion, trosine kinase may be one of the key factors in the regulation of $\alpha3\beta4$ nAChRs in rat MPG neurons, which may play an important roles in the autonomic neuronal function such as synaptic transmission, autonomic reflex, and neuronal plasticity.

• Parasites, Hosts and Diseases
• /
• v.58 no.3
• /
• pp.287-299
• /
• 2020

Cystic echinococcosis (CE) is a zoonotic infection caused by Echinococcus granulosus larvae. It seriously affects the development of animal husbandry and endangers human health. Due to a poor understanding of the cystic fluid formation pathway, there is currently a lack of innovative methods for the prevention and treatment of CE. In this study, the protoscoleces (PSCs) in the encystation process were analyzed by high-throughput RNA sequencing. A total of 32,401 transcripts and 14,903 cDNAs revealed numbers of new genes and transcripts, stage-specific genes, and differently expressed genes. Genes encoding proteins involved in signaling pathways, such as putative G-protein coupled receptor, tyrosine kinases, and serine/threonine protein kinase, were predominantly up-regulated during the encystation process. Antioxidant enzymes included cytochrome c oxidase, thioredoxin glutathione, and glutathione peroxidase were a high expression level. Intriguingly, KEGG enrichment suggested that differentially up-regulated genes involved in the vasopressin-regulated water reabsorption metabolic pathway may play important roles in the transport of proteins, carbohydrates, and other substances. These results provide valuable information on the mechanism of cystic fluid production during the encystation process, and provide a basis for further studies on the molecular mechanisms of growth and development of PSCs.

• BMB Reports
• /
• v.38 no.6
• /
• pp.639-645
• /
• 2005

Protein kinase C (PKC) isozymes, a family of serine-threonine kinases, are important regulators of cell proliferation and malignant transformation. Phorbol esters, the prototype PKC activators, cause PKC translocation to the plasma membrane in prostate cancer cells, and trigger an apoptotic response. Studies in recent years have determined that each member of the PKC family exerts different effects on apoptotic or survival pathways. $PKC{\delta}$, one of the novel PKCs, is a key player of the apoptotic response via the activation of the p38 MAPK pathway. Studies using RNAi revealed that depletion of $PKC{\delta}$ totally abolishes the apoptotic effect of the phorbol ester PMA. Activation of the classical $PKC{\alpha}$ promotes the dephosphorylation and inactivation of the survival kinase Akt. Studies have assigned a pro-survival role to $PKC{\varepsilon}$, but the function of this PKC isozyme remains controversial. Recently, it has been determined that the PKC apoptotic effect in androgen-dependent prostate cancer cells is mediated by the autocrine secretion of death factors. $PKC{\delta}$ stimulates the release of $TNF{\alpha}$ from the plasma membrane, and blockade of $TNF{\alpha}$ secretion or $TNF{\alpha}$ receptors abrogates the apoptotic response of PMA. Molecular analysis indicates the requirement of the extrinsic apoptotic cascade via the activation of death receptors and caspase-8. Dissecting the pathways downstream of PKC isozymes represents a major challenge to understanding the molecular basis of phorbol ester-induced apoptosis.

• Biomolecules & Therapeutics
• /
• v.25 no.5
• /
• pp.519-527
• /
• 2017

Excessive activation of microglia causes the continuous production of neurotoxic mediators, which further causes neuron degeneration. Therefore, inhibition of microglial activation is a possible target for the treatment of neurodegenerative disorders. Balanophonin, a natural neolignoid from Firmiana simplex, has been reported to have anti-inflammatory and anti-cancer effects. In this study, we aimed to evaluate the anti-neuroinflammatory effects and mechanism of balanophonin in lipopolysaccharide (LPS)-stimulated BV2 microglia cells. BV2 microglia cells were stimulated with LPS in the presence or absence of balanophonin. The results indicated that balanophonin reduced not only the LPS-mediated TLR4 activation but also the production of inflammatory mediators, such as nitric oxide (NO), prostaglandin E2 (PGE2), $Interleukin-1{\beta}$ ($IL-1{\beta}$), and tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$), in BV2 cells. Balanophonin also inhibited LPS-induced inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX2) protein expression and mitogen activated protein kinases (MAPKs), including extracellular signal-regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK), and p38 MAPK. Interestingly, it also inhibited neuronal cell death resulting from LPS-activated microglia by regulating cleaved caspase-3 and poly ADP ribose polymerase (PARP) cleavage in N2a cells. In conclusion, our data indicated that balanophonin may delay the progression of neuronal cell death by inhibiting microglial activation.

• Korean Journal of Pharmacognosy
• /
• v.45 no.1
• /
• pp.1-10
• /
• 2014

Ginsenoside Rg3 (G-Rg3) is one of protopanaxadiol ginsenosides characteristic of red ginseng, steamed and dried ginseng (Panax ginseng), which has recently attracted much attention for its antitumor properties in vitro and in vivo animal models. Experimental studies have demonstrated that it could promote cancer cell apoptosis, inhibit cancer cell growth, the apoptosis of cancer cells, adhesion, invasion and metastasis, and also prevent an angiogenetic formation in prostate, breast, ovarian, colorectal, gastric, liver and lung cancer etc. It has shown the antitumor activities by modulation of diverse signaling pathways, including regulation of cell proliferation mediators (CDKs and cyclins), growth factors (vascular endothelial growth factor), tumor suppressors (p53 and p21), cell death mediators (caspases, Bcl-2, Bax), inflammatory response molecules ($NF-{\kappa}B$ and COX-2), protein kinases (JNK, Akt, and AMP-activated protein kinase) and Wnt/${\beta}$-catenin signaling. In addition, the combination of Rg3 and chemotherapeutic agents have synergistically enhanced therapeutic efficacy and reduced antagonistically side effects. Furthermore, it can reverse the multidrug resistance of cancer cells, prolong the survival duration and improve life quality of cancer patients. Taken together, accumulating evidences could provide the potential of G-Rg3 in the treatment of cancers and the feasibility of further randomized placebo controlled clinical trials.

• Journal of Microbiology and Biotechnology
• /
• v.25 no.7
• /
• pp.1047-1055
• /
• 2015

For the search of a potent first-in-class compound to inactivate macrophages responsible for inflammatory responses, in the present study, we investigated the anti-nflammatory effects of YH-1118, a novel synthetic compound, in a lipopolysaccharide (LPS)-stimulated mouse macrophage cell line, Raw 264.7. YH-1118 inhibited LPS-induced nitric oxide (NO) production and inducible NO synthase (iNOS) expression at both the protein and mRNA levels. The suppression of LPS-induced iNOS expression by YH-1118 was mediated via nuclear factor kappa B (NF-κB), but not activator protein-1 (AP-1) transcription factor. This was supported by the finding that YH-1118 attenuated the phosphorylation of inhibitor of κBα (IκBα) and nuclear translocation and DNA binding activity of NF-κB. Through the mechanisms that YH-1118 inhibited the activation of IκB kinases (IKKs), upstream activators of NF-κB, or p38 MAPK, YH-1118 significantly suppressed LPS-induced production of pro-inflammatory cytokines, tumor necrosis factor-α, interleukin-1β (IL-1β), and IL-6 (p < 0.05). In conclusion, our results suggest that YH-1118 inhibits LPS-induced inflammatory responses by blocking IKK and NF-κB activation in macrophages, and may be a therapeutic candidate for the treatment of various inflammatory diseases.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.7
• /
• pp.2909-2914
• /
• 2015

Objective: To investigate the protective effect of quercetin on radiation induced lung injury (RILI) and related mechanisms. Materials and Methods: Mice treated with radiation and/or quercetin were sacrificed at 1-8 weeks after irradiation under anesthesia. Lung tissues were collected for histological examination. Immunohistochemistry (IHC) and Western blotting were performed to detect the protein expression of nuclear factor-${\kappa}B$ ($NF-{\kappa}B$) and Mitogen-activated protein kinases (MAPK) pathway. Results: Hematoxylin and eosin (HE) staining showed that radiation controls displayed more severe lung damage than quercetin groups, either high or low dose. Results of IHC and Western blotting demonstrated the expression level of $NF-{\kappa}B$ to be decreased and that of an inhibitor of $NF-{\kappa}B$ ($I{\kappa}b-{\alpha}$) to be increased by the quercetin intervention compared with the radiation control group. Numbers of JNK/SAPK, p38 and p44/p42 positive inflammatory cells were decreased in the radiation+quercetin injection group (P<0.05). Conclusions: Quercetin may play a radio-protective role in mice lung via suppression of $NF-{\kappa}B$ and MAPK pathways.

• BMB Reports
• /
• v.53 no.3
• /
• pp.154-159
• /
• 2020

We investigated the effects of physalin A, B, D, and F on osteoclastogenesis induced by receptor activator of nuclear factor κB ligand (RANKL). The biological functions of different physalins were first predicted using an in silico bioinformatic tool (BATMAN-TCM). Afterwards, we tested cell viability and cell apoptosis rate to analyze the cytotoxicity of different physalins. We analyzed the inhibitory effects of physalins on RANKL-induced osteoclastogenesis from mouse bone-marrow macrophages (BMMs) using a tartrate-resistant acid phosphatase (TRAP) stain. We found that physalin D has the best selectivity index (SI) among all analyzed physalins. We then confirmed the inhibitory effects of physalin D on osteoclast maturation and function by immunostaining of F-actin and a pit-formation assay. On the molecular level, physalin D attenuated RANKL-evoked intracellular calcium ([Ca(2+)](i)) oscillation by inhibiting phosphorylation of phospholipase Cγ2 (PLCγ2) and thus blocked the downstream activation of Ca2+/calmodulin-dependent protein kinases (CaMK)IV and cAMP-responsive element-binding protein (CREB). An animal study showed that physalin D treatment rescues bone microarchitecture, prevents bone loss, and restores bone strength in a model of rapid bone loss induced by soluble RANKL. Taken together, these results suggest that physalin D inhibits RANKL-induced osteoclastogenesis and bone loss via suppressing the PLCγ2-CaMK-CREB pathway.

• BMB Reports
• /
• v.36 no.2
• /
• pp.223-229
• /
• 2003

The product of a tree (Tabebuia avellanedae) from South America, $\beta$-lapachone, is known to exhibit various pharmacological properties, the mechanisms of which are poorly understood. The aim of the present study was to further elucidate the possible mechanisms by which $\beta$-lapachone exerts its anti-proliferative action in cultured human prostate cancer cells. We observed that the proliferation-inhibitory effect of $\beta$-lapachone was due to the induction of apoptosis, which was confirmed by observing the morphological changes and cleavage of the poly(ADP-ribose) polymerase protein. A DNA flow cytometric analysis also revealed that $\beta$-lapachone arrested the cell cycle progression at the G1 phase. The effects were associated with the down-regulation of the phosphorylation of the retinoblastoma protein (pRB) as well as the enhanced binding of pRB and the transcription factor E2F-1. Also, $\beta$-lapachone suppressed the cyclindependent kinases (Cdks) and cyclin E-associated kinase activity without changing their expressions. Furthermore, this compound induced the levels of the Cdk inhibitor $p21^{WAF1/CIP1}$ expression in a p53-independent manner, and the p21 proteins that were induced by $\beta$-lapachone were associated with Cdk2. $\beta$-lapachone also activated the reporter construct of a p21 promoter. Overall, our results demonstrate a combined mechanism that involves the inhibition of pRB phosphorylation and induction of p21 as targets for $\beta$-lapachone. This may explain some of its anticancer effects.

• BMB Reports
• /
• v.45 no.10
• /
• pp.583-588
• /
• 2012

Leukotactin(Lkn)-1 is a CC chemokine and is upregulated in macrophages in response to Mycobacterium tuberculosis (MTB) infection. We investigated whether mitogen-activated protein kinases (MAPKs) are involved in MTB-induced expression of Lkn-1. The up-regulation of Lkn-1 by infection with MTB was inhibited in cells treated with inhibitors specific for JNK (SP600125) or p38 MAPK (SB202190). Since the up-regulation of Lkn-1 by MTB has been reported to be mediated by the PI3-K/PDK1/Akt signaling, we examined whether JNK and/or p38 MAPK are also involved in this signal pathway. MTB-induced Akt phosphorylation was blocked by treatment with JNK- or p38 MAPK-specific inhibitors implying that p38 and JNK are upstream of Akt. In addition, treatment with the PI3-K-specific inhibitor inhibited MTB-stimulated activation of JNK or p38 MAPK implying that PI3-K is upstream of JNK and p38 MAPK. These results collectively suggest that JNK and p38 MAPK are involved in the signal pathway responsible for MTB-induced up-regulation of Lkn-1.