• Physical Therapy Rehabilitation Science
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• v.3 no.1
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• pp.33-37
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• 2014

Objective: Low intensity pulsed ultrasound (LIPUS) has been shown to accelerate cell proliferation and tissue healing in both animal models and clinical trials. However, details of the clinical effects of LIPUS have not been well characterized. The aim of this study was to investigate the effect of LIPUS on mitogen-activated protein kinase (MAPK) activation in rat articular chondrocytes. Design: Cross-sectional study. Methods: Chondrocyte were cultured in six well cell culture plates for 72 hours at $37^{\circ}C$ with 5% $CO_2$, and then exposed to LIPUS at 1.5 MHz frequency and $30-mW/cm^2$ power. Changes in chondrocyte activities were evaluated in response to oxydative stress in dose-dependent (0 and 300 uM) and time-dependent (0-24 hr) manner. The cell viability were analyzed using MTT [3-(4.5-dimethylthiazol-2-yl)-2.5 diphenyltetrazolium bromide]. The expression of p38 MAPK was measured using western blotting. Results: Oxidative stress was induced in rat chondrocytes using hydrogen peroxide ($H_2O_2$). The cell viability was decreased in chondrocytes after the $H_2O_2$ dose and time-dependent treatment. The p38 MAPK phosphorylation occurred at a significantly increased rate after $H_2O_2$ treated (p<0.05). Expression of p38 MAPK was decreased in the p38 inhibitor groups compared with the oxidative stress-induced chondrocyte damage via the p38 MAPK signaling pathways (p<0.05). Conclusions: It could be concluded that LIPUS can inhibit oxidative stress-induced chondrocyte damage via the p38 MAPK signaling pathways.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.6
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• pp.365-369
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• 2010

In this study, we examined whether melatonin promotes apoptotic cell death via p53 in prostate LNCaP cells. Melatonin treatment significantly curtailed the growth of LNCaP cells in a dose- and time-dependent manner. Melatonin treatment (0 to 3 mM) induced the fragmentation of poly(ADP-ribose) polymerase (PARP) and activation of caspase-3, caspase-8, and caspase-9. Moreover, melatonin markedly activated Bax expression and decreased Bcl-2 expression in dose increments. To investigate p53 and p21 expression, LNCaP cells were treated with 0 to 3 mM melatonin. Melatonin increased the expressions of p53, p21, and p27. Treatment with mitogen-activated protein kinase (MAPK) inhibitors, PD98059 (ERK inhibitor), SP600125 (JNK inhibitor) and SB202190 (p38 inhibitor), confirmed that the melatonin-induced apoptosis was p21-dependent, but ERK-independent. With the co-treatment of PD98059 and melatonin, the expression of p-p53, p21, and MDM2 did not decrease. These effects were opposite to the expression of p-p53, p21, and MDM2 observed with SP600125 and SB202190 treatments. Together, these results suggest that p53-dependent induction of JNK/p38 MAPK directly participates in apoptosis induced by melatonin.

• Journal of Oral Medicine and Pain
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• v.32 no.4
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• pp.357-364
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• 2007

This experiment was designed to clarify the effect of extracellular glucose on the osteoblasts and periodontal ligament cells. The cells were incubated for 24 and 48 hours with ${\alpha}$-MEM including 1,000 mg/L (control group) and 4,500 mg/L (experimental group) of glucose. Then, the expressions of caspase-3, p38 MAPK, JNK-1, and ERK-1 were examined using Elisa assay and Western blot. The results were as follows: 1. The expression of caspase-3 and p38 MAPK was increased by the high extracellular glucose in both cells. 2. The expression of caspase-3 and p38 MAPK was increased greatly in the periodontal ligament cells than the E1 cells by the high extracellular glucose. 3. The expression of JNK-1 was increased by the high extracellular glucose in both cells. 4. The expression of ERK-1 was not changed by the high extracellular glucose in both cells. These results suggest that extracellular glucose at high concentrations may inhibit the periodontal regeneration process increasing cellular apoptosis. And p38 MAPK and JNK-1 pathway may be the most responsible intracellular pathway rather than ERK-1.

• Journal of Life Science
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• v.21 no.11
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• pp.1549-1557
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• 2011

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can selectively induce apoptosis in many types of transformed cells; however, some human hepatocellular carcinoma cells are particularly resistant to the effects of TRAIL. Although genistein, a natural isoflavonoid phytoestrogen, has been shown to have pro-apoptotic activity against human cancer cell lines, little is known about the mechanism of genistein in terms of TRAIL-induced apoptosis. In the present study, it was investigated whether or not combined treatment with genistein and TRAIL synergistically induced apoptosis in Hep3B hepatocarcinoma cells. Results indicate that treatment with TRAIL in combination with nontoxic concentrations of genistein sensitized TRAIL-resistant Hep3B cells to TRAIL-induced apoptosis, which was associated with mitochondrial dysfunction. Further, the inhibition of p38 mitogen-activated protein kinase (MAPK) activation markedly decreased genistein and TRAIL-induced cell viability and apoptosis by enhanced truncation of Bid, increase of pro-apoptotic Bax, decrease of anti-apoptotic Bcl-2, and release of cytochrome c from mitochondria to cytoplasm. Activation of caspases and degradation of poly (ADP-ribose) polymerase induced by the combined treatment was also markedly increased by the inhibition of p38 MAPK, through the mitochondrial amplification step. In conclusion, our data suggest that genistein sensitizes TRAIL-induced-apoptosis via p38 MAPK-dependent pathway.

• Biomedical Science Letters
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• v.15 no.4
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• pp.343-347
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• 2009

Cytochalasin D (CD) is known as a disruptor of actin cytoskeleton architecture in chondrocytes. We have studied the role of CD in retinoic acid (RA) caused dedifferentiation and inflammation responses in rabbit articular chondrocytes. We have examined the effect of CD on RA induced dedifferentiation of chondrocytes. CD inhibited RA induced dedifferentiation determined by Western blot analysis and Alcian blue staining in rabbit articular chondrocytes. Also, CD additionally reduced inflammation response molecules such as cyclooxygenase-2 (COX-2) and prostaglandin $E_2$ ($PGE_2$) in RA treated cells. Treatment of CD reduced phosphorylation of p38 by treatment of RA. Inhibiton of p38kinase with SB203580 reduced expression of COX-2 and production of $PGE_2$ by treatment of CD in RA treated cells. But, Inhibiton of p38kinase with SB203580 did not any relationship with effect of CD on RA caused dedifferentiation. In summary, our results indicate that CD regulates RA reduced expression of COX-2 and production of PGE2 via p38kinase pathway.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.15
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• pp.6321-6326
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• 2014

${\alpha}$-Methyl-n-butylshikonin (MBS), one of the active components in the root extracts of Lithospermum erythrorhizon, posses antitumor activity. In this study, we assess the molecular mechanisms of MBS in causing apoptosis of SW620 cells. MBS reduced the cell viability of SW620 cells in a dose-and time-dependent manner and induced cell apoptosis. Treatment of SW620 cells with MBS down-regulated the expression of Bcl-2 and up-regulated the expression of Bak and caused the loss of mitochondrial membrane potential. Additionally, MBS treatment led to activation of caspase-9, caspase-8 and caspase-3, and cleavage of PARP, which was abolished by pretreatment with the pan-caspase inhibitor Z-VAD-FMK. MBS also induced significant elevation in the phosphorylation of JNK and p38. Pretreatment of SW620 cells with specific inhibitors of JNK (SP600125) and p38 (SB203580) abrogated MBS-induced apoptosis. Our results demonstrated that MBS inhibited growth of colorectal cancer SW620 cells by inducing JNK and p38 signaling pathway, and provided a clue for preclinical and clinical evaluation of MBS for colorectal cancer therapy.

• BMB Reports
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• v.43 no.12
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• pp.824-829
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• 2010

Melanin synthesis is regulated by melanocyte specific enzymes and related transcription factors. $\beta$-carboline alkaloids including harmaline and harmalol are widely distributed in the environment including several plant families and alcoholic beverages. Presently, melanin content and tyrosinase activity were increased in melanoma cells by harmaline and harmalol in concentration- and time-dependent manners. Increased protein levels of tyrosinase, tyrosinase-related protein-1 (TRP-1), and TRP-2 were also evident. In addition, immunofluorescence and Western blot analyses revealed harmaline and harmalol increased cAMP response element binding protein phosphorylation and microphthalmia-associated transcription factor expression. In addition to studying the signaling that leads to melanogenesis, roles of the p38 MAPK pathways by the harmaline and harmalol were investigated. Harmaline and harmalol induced time-dependent phosphorylation of p38 MAPK. Harmaline and harmalol stimulated melanin synthesis and tyrosinase activity, as well as expression of tyrosinase and TRP-1 and TRP-2 indicating that these harmaline and harmalol induce melanogenesis through p38 MAPK signaling.

• Journal of Applied Biological Chemistry
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• v.64 no.4
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• pp.323-331
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• 2021

Lincomycin is a lincosamide antibiotic isolated from the actinomycete Streptomyces lincolnensis. Moreover, it has been found to be effective against infections caused by Staphylococcus, Streptococcus, and Bacteroides fragillis. To identify the melanin-inducing properties of lincomycin, we used B16F10 melanoma cells in this study. The melanin content and intracellular tyrosinase activity in the cells were increased by lincomycin, without any cytotoxicity. Western blot analysis indicated that the protein expressions of tyrosinase, tyrosinase related protein 1 (TRP1) and TRP2 increased after lincomycin treatment. In addition, lincomycin enhanced the expression of master transcription regulator of melanogenesis, a microphthalmia-associated transcription factor (MITF). Lincomycin also increased the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and decreased the AKT phosphorylation. Moreover, the activation of tyrosinase activity by lincomycin was inhibited by the treatment with SB203580, which is p38 inhibitor. Furthermore, we also found that lincomycin-induced tyrosinase expression was reduced by H-89, a specific protein kinase A (PKA) inhibitor. These results indicate that lincomycin stimulate melanogenesis via MITF activation via p38 MAPK, AKT, and PKA signal pathways. Thus, lincomycin can potentially be used for treatment of hypopigmentation disorders.

• BMB Reports
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• v.57 no.5
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• pp.238-243
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• 2024

Bone marrow-derived mesenchymal stem cells (BM-MSCs) can differentiate into endothelial cells in an inflammatory microenvironment. However, the regulatory mechanisms underlying this process are not entirely understood. Here, we found that TIE2 in BM-MSCs was upregulated at the transcriptional level after stimulation with tumor necrosis factor-alpha (TNFα), a major pro-inflammatory cytokine. Additionally, the STAT-binding sequence within the proximal region of TIE2 was necessary for TNFα-induced TIE2 promoter activation. TIE2 and STAT3 knockdown reduced TNFα-induced endothelial tube formation in BM-MSCs. Among the major TNFα-activated MAP kinases (ERK1/2, JNK1/2, and p38 MAPK) in BM-MSCs, only inhibition of the p38 kinase abrogated TNFα-induced TIE2 upregulation by inhibiting the JAK-STAT signaling pathway. These findings suggest that p38 MAP contributes to the endothelial differentiation of BM-MSCs by activating the JAK-STAT-TIE2 signaling axis in the inflammatory microenvironment.

• Toxicological Research
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• v.22 no.3
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• pp.293-299
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• 2006

We demonstrate that magnolol, a hydroxylated biphenyl compound isolated from Magnolia officinalis, inhibits LPS-induced expression of iNOS gene in RAW 264.7 cells(murine macrophage cell line). Treatment of RAW 264.7 cells with magnolol inhibited LPS-stimulated nitric oxide production in a dose-related manner. RT-PCR analysis showed that the decrease of NO was due to the inhibition of iNOS gene expression. Western immunoblot analysis of phosphorylate p38 kinase showed magnolol significantly inhibited the phosphorylation of p38 kinase which is important in the regulation of iNOS gene expression. The specific p38 inhibiter SB203580 abrogated the LPS-induced NO generation and iNOS expression, whereas the selective MEK-1 inhibitor PD98059 did not affect the NO induction. Immunostaining of p65 and reporter gene assay showed that magnolol inhibited NF-${\kappa}/Rel$ nuclear translocation and transcriptional activation, respectively. Collectively, this series of experiments indicates that magnolol inhibits iNOS gene expression by blocking NF-k/Rel and p38 kinase signaling. Due to the critical role that NO release plays in mediating inflammatory responses, the inhibitory effects of magnolol or iNOS suggest that magnolol may represent a useful anti-inflammatory agent.