• The Korean Journal of Physiology and Pharmacology
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• v.26 no.5
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• pp.389-396
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• 2022

The increased expression of receptors for advanced glycation end-product (RAGE) is known as a key player in the progression of vascular remodeling. However, the precise signal pathways regulating RAGE expression in vascular smooth muscle cells (VSMCs) in the injured vasculatures are unclear. Given the importance of mitogen-activated protein kinase (MAPK) signaling in cell proliferation, we investigated the importance of MAPK signaling in high-mobility group box 1 (HMGB1)-induced RAGE expression in VSMCs. In HMGB1 (100 ng/ml)-stimulated human VSMCs, the expression of RAGE mRNA and protein was increased in association with an increase in AGE-induced VSMC proliferation. The HMGB1-induced RAGE expression was attenuated in cells pretreated with inhibitors for ERK (PD98059, 10 μM) and p38 MAPK (SB203580, 10 μM) as well as in cells deficient in ERK and p38 MAPK using siRNAs, but not in cells deficient of JNK signaling. In cells stimulated with HMGB1, the phosphorylation of ERK, JNK, and p38 MAPK was increased. This increase in ERK and p38 MAPK phosphorylation was inhibited by p38 MAPK and ERK inhibitors, respectively, but not by JNK inhibitor. Moreover, AGE-induced VSMC proliferation in HMGB1-stimulated cells was attenuated in cells treated with ERK and p38 MAPK inhibitors. Taken together, our results indicate that ERK and p38 MAPK signaling are involved in RAGE expression in HMGB1-stimulated VSMCs. Thus, the ERK/p38 MAPK-RAGE signaling axis in VSMCs was suggested as a potential therapeutic target for vascular remodeling in the injured vasculatures.

• BMB Reports
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• v.35 no.3
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• pp.267-272
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• 2002

TNF-$\alpha$ elicits various responses including apoptosis, proliferation, and differentiation according to cell type. In neuronal PC12 cells, TNF-$\alpha$ induces moderate apoptosis while lipopolysarccaharide or trophic factor deprivation can potentiate apoptosis that is induced by TNF-$\alpha$. TNF-$\alpha$ initiates various signal transduction pathways leading to the activation of the caspase family, NF-${\kappa}B$, Jun N-terminal kinase, and p38 MAPK via the death domain that contains the TNF-$\alpha$ receptor. Inhibition of translation using cycloheximide greatly enhanced the apoptotic effect of TNF-$\alpha$. This implies that the induction of anti-apoptotic genes for survival by TNF-$\alpha$ may be able to protect PC12 cells from apoptosis. Accordingly, Bcl-2, an anti-apoptotic genes for survival by TNF-$\alpha$ may be able to protect PC12 cells from apoptosis. Accordingly, Bcl-2, an anti-apoptotic Bcl-2 family member, was highly expressed in response to TNF-$\alpha$. In this study, we examined the anti-apoptotic role of p38 MAPK that is activated by TNF-$\alpha$ in neuronal PC12 cells. The phosphorylation of p38 MAPK in response to TNF-$\alpha$ slowly increased and lasted several hours in the PC12 cell and DRG neuron. This specific inhibitor of p38 MAPK, SB202190, significantly enhanced the apoptosis that was induced by TNF-$\alpha$ in PC12 cells. This indicates that the activation of p38 MAPK could protect PC12 cells from apoptosis since there is no known role of p38 MAPK in resoonse to TNF-$\alpha$ in neuron. This discovery could be evidence for the neuroprotective role of the p38 MAPK.

• The Journal of Korean Physical Therapy
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• v.20 no.3
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• pp.53-59
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• 2008

Purpose: The non-receptor-type protein tyrosine kinase Syk (636 amino acids, 72 kDa) is ubiquitously expressed in hematopoietic stem cells and has been widely studied as a regulator and effector of B cell receptor signaling that occurs in processes such as differentiation, proliferation and apoptosis. However, the mechanism relating Syk and p38 mitogen-activated protein kinases (p38MAPK) by endothelin-1 (ET-1, 21 amino acids) stimulation in muscle cells, especially in the volume-dependent hypertensive state, remains unclear. Methods: In this study, we investigated the relationship between Syk and p38MAPK for isometric contraction and enzymatic activity by ET-1 from rat aortic smooth muscle cells and aldosterone-analogue deoxycorticosterone acetate (DOCA) hypertensive state rats (ADHR). Results: The systolic blood pressure was significantly increased in ADHR than in a control group of animals. ET-1 induced isometric contraction and phosphorylation of p38MAPK, which was increased in muscle strips from ADHR. Increased vasoconstriction and phosphorylation of p38MAPK induced by treatment with 30 nM ET-1 were inhibited by the use of 10${\mu}M$ SB203580, an inhibitor of p38MAPK from ADHR. Furthermore, ET-1 induced isometric contraction and phosphorylation of Syk and p38MAPK, which were increased in the aortic smooth muscle cells. Increased tension and phosphorylation of Syk and p38MAPK induced by ET-1 were inhibited by SB203580 from rat aortic smooth muscle cells. Conclusion: These results, suggest that the Syk activity affects ET-1-induced contraction through p38MAPK in smooth muscle cells and that the same pathway directly or indirectly is associated with volume dependent hypertension. The findings suggest the need to develop cardiovascular disease-specialized physical therapy.

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

• Journal of Life Science
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• v.19 no.8
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• pp.1119-1124
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• 2009

Hyperlipidemia has been reported to be associated with the development of fatty liver. Palmitic acid, a major saturated fatty acid, is involved in the development of diverse diseases. The activation of mitogen activated protein kinases (MAPKs), such as Jun N-terminal kinase (INKs) and p38 MAPK is implicated in the apoptosis in diverse cells. Thus, this study was conducted to investigate the effects of palmitic acid on apoptosis and its relationship between JNK and p38 MAPK in cultured rat hepatocytes. In the present study, palmitic acid (>50 uM) decreased cell proliferation and increased lactate dehydrogenase activity in hepatocytes, which was blocked by the treatment of SP600125 (a JNK inhibitor) and SB203580 (a p38 MAPK inhibitor). Indeed, palmitic acid decreased Bcl-2 expression but increased Bax expression in rat hepatocytes, which was blocked by the treatment of SP600125 and SB203580. In addition, palmitic acid decreased glutathione (GSH) content and increased lipid peroxide formation, which was blocked by the treatment of SP600125 and SB203580. Western immunoblotting analysis also revealed that palmitic acid increased JNK and p38 MAPK. In conclusion, palmitic acid induced apoptosis through oxidative stress via JNK and p38 MAPK activation in rat hepatocytes.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.11
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• pp.4519-4525
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• 2014

Oleanolic acid (OA) is a nutritional component widely distributed in various vegetables. Although it has been well recognized for decades that OA exerts certain anti-tumor activity by inducing mitochondria-dependent apoptosis, it is still unclear that what molecular signaling is responsible for this effect. In this study, we employed cancer cell lines, A549, BXPC-3, PANC-1 and U2OS to elucidate the molecular mechanisms underlying OA anti-tumor activity. We found that activation of MAPK pathways, including p-38 MAPK, JNK and ERK, was triggered by OA in both a dose and time-dependent fashion in all the tested cancer cells. Activation was accompanied by cleavage of caspases and PARP as well as cytochrome C release. SB203580 (p38 MAPK inhibitor), but not SP600125 (JNK inhibitor) and U0126 (ERK inhibitor), rescued the pro-apoptotic effect of OA on A549 and BXPC-3 cells. OA induced p38 MAPK activation promoted mitochondrial translocation of Bax and Bim, and inhibited Bcl-2 function by enhancing their phosphorylation. OA can induce reactive oxygen species (ROS)-dependent ASK1 activation, and this event was indispensable for p38 MAPK-dependent apoptosis in cancer cells. In vivo, p38 MAPK knockdown A549 tumors proved resistant to the growth-inhibitory effect of OA. Collectively, we elucidated that activation of ROS/ASK1/p38 MAPK pathways is responsible for the apoptosis stimulated by OA in cancer cells. Our finding can contribute to a better understanding of molecular mechanisms underlying the antitumor activity of nutritional components.

• Biomedical Science Letters
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• v.9 no.4
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• pp.241-248
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• 2003

Sodium salicylate, a plant stress hormone that plays an important role(s) in defenses against pathogenic microbial and herbivore attack, has been shown to induce a variety of cell responses such as anti-inflammation, cell cycle arrest and apoptosis in animal cells. p38MAPK plays a critical role(s) in the cell regulation by sodium salicylate. However, the signal pathway for sodium salicylate-induced p38MAPK activation is yet unclear. In this study, we show that although sodium salicylate enhances reactive oxygen species (ROS) production, N-acetyl-L-cysteine, a general ROS scavenger, did not prevent sodium salicylate-induced p38MAPK, indicating ROS-independent activation of p38MAPK by sodium salicylate. Sodium salicylate-activated p38MAPK appeared to be very rapidly down-regulated 2 min after removal of sodium salicylate. Interestingly, sodium salicylate-pretreated cells remained fully responsive to re-induction of p38MAPK activity by a second sodium salicylate stimulation or by other stresses, $H_2O$$_2$ and methyl jasmonate (MeJA), thereby indicating that sodium salicylate does not exhibit both homologous and heterologous desensitization. In contrast, pre-exposure to MeJA, $H_2O$$_2$, heat shock, or hyperosmotic stress reduced the responsiveness to subsequent homologous stimulation. Sodium salicylate was able to activate p38MAPK in cells desensitized by other heterologous p38MAPK activators. These results indicate that there is a sensing mechanism highly specific to sodium salicylate for activation of p38MAPK, distinct trom pathways used by other stressors such as MeJA, $H_2O$$_2$ heat shock, and hyperosmotic stress.

• Molecules and Cells
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• v.22 no.1
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• pp.44-50
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• 2006

We investigated the possible role of p38 MAPK and $ET_B$ receptors in ET-1 induction of cyclooxygenase-2 (COX-2) and prostaglandin $E_2$ ($PGE_2$) in cultured feline esophageal smooth muscle cells (ESMC). Confluent layers of ESMC were stimulated with 10 nM ET-1 and expression of COX-1 and COX-2, involvement of receptors, and activation of p38 MAPK, were examined by Western blot analysis. Levels of $PGE_2$ induced by ET-1 were measured by Elisa. Using $ET_A$and $ET_B$ antagonists (BQ-123 and BQ-788, respectively), the contribution of the ET receptors to COX-1 and COX-2 expression induced by ET-1 was determined. Western blot analysis revealed that treatment of ESMC with ET-1 resulted in transient expression of COX-2 and activation of p38 MAPK. Activation of p38 MAPK was maximal after 1 h. SB202190, a p38 MAPK inhibitor, reduced expression of COX-2, but not COX-1. ET-1-induced release of $PGE_2$ was also blocked by SB202190. COX-2 expression was upregulated only via the $ET_B$ receptor, and COX-1 expression was not affected by either antagonist. Taken together, our data suggest that ET-1 causes p38 MAPK-dependent expression of COX-2 by interacting with $ET_B$ receptors on ESMC.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.5
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• pp.447-453
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• 2013

Osteoblastic activity of nectandrin A was examined in C2C12 cells. Nectandrin A enhances the BMP-induced osteoblastic differentiation and mineralization, manifested by the up-regulation of differentiation markers (alkaline phosphatase and osteogenic genes) and increased calcium contents. In C2C12 cells co-transfected with expression vector encoding Smad4 and Id1-Luc reporter, nectandrin A increased Id1 luciferase activity in a concentration-dependent manner, when compared to that in BMP-2 treated cells, indicating that Smad signaling pathway is associated with nectandrin A-enhanced osteoblastic differentiation in C2C12 cells. In addition, nectandrin A activated p38 mitogen-activated protein kinase (MAPK) in time- and concentration-dependent manners, and phosphorylated form of pSmad1/5/8 and alkaline phosphatase activity were both decreased when the cells were pretreated with SB203580, a p38 MAPK inhibitor, suggesting that p38 MAPK might be an upstream kinase for Smad signaling pathway. Taken together, nectandrin A enhances the BMP-induced osteoblastic differentiation and mineralization of C2C12 cells via activation of p38 MAPK-Smad signaling pathway, and it has a therapeutic potential for osteoporosis by promoting bone formation.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1183-1186
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• 2012

Objective: To observe the effect of insulin-like growth factor-1 (IGF-1) on bone morphogenetic protein (BMP)-2 expression in hepatocellular carcinoma SMMC7721 cells. Methods: Cells were divided into blank control, IGF-1, IGF-1 + SB203580, and SB203580 groups. SB203580 was used to block the p38 MAPK signaling pathway. Changes in the expression of BMP-2, p38 MAPK, and phosphorylated p38, MERK, ERK and JNK were determined using reverse transcription polymerase chain reactions (RT-PCR) and Western blot analysis. Results: Protein expression of phosphorylated BMP-2, MERK, ERK, and JNK was significantly up-regulated by IGF-1 compared with the control group ($1.138{\pm}0.065$ vs. $0.606{\pm}0.013$, $0.292{\pm}0.005$ vs. $0.150{\pm}0.081$, $0.378{\pm}0.006$ vs. $0.606{\pm}0.013$, and $0.299{\pm}0.015$ vs. $0.196{\pm}0.017$, respectively; P<0.05). Levels of BMP-2 and phosphorylated MERK and JNK were significantly reduced after blocking of the p38MAPK signaling pathway ($0.494{\pm}0.052$ vs. $0.165{\pm}0.017$, $0.073{\pm}0.07$ vs. $0.150{\pm}0.081$, and $0.018{\pm}0.008$ vs. $0.196{\pm}0.017$, respectively; P<0.05), but such a significant difference was not observed for phosphorylated ERK protein expression ($0.173{\pm}0.07$ vs. $0.150{\pm}0.081$, P>0.05). Conclusion: IGF-1 can up-regulate BMP-2 expression, and p38 MAPK signaling pathway blockage can noticeably reduce the up-regulated expression. We can conclude that the up-regulatory effect of IGF-1 on BMP-2 expression is realized through the p38 MAPK signaling pathway.