p38 MAP kinase mediates platelet-derived growth factor-stimulated migration of hepatic myofibroblasts

2002 ◽  
Vol 191 (3) ◽  
pp. 351-361 ◽  
Author(s):  
Pisit Tangkijvanich ◽  
Chintda Santiskulvong ◽  
Andrew C. Melton ◽  
Enrique Rozengurt ◽  
Hal F. Yee,
2001 ◽  
Vol 280 (5) ◽  
pp. L955-L964 ◽  
Author(s):  
Kristen Page ◽  
Jing Li ◽  
Marc B. Hershenson

We have demonstrated that platelet-derived growth factor (PDGF) stimulates p38 mitogen-activated protein (MAP) kinase activation in bovine tracheal myocytes, suggesting that p38 is involved in growth regulation. We therefore examined whether p38 regulates expression of cyclin D1, a G1 cyclin required for cell cycle traversal. The chemical p38 inhibitors SB-202190 and SB-203580 each increased basal and PDGF-induced cyclin D1 promoter activity and protein abundance. Overexpression of a dominant negative allele of MAP kinase kinase-3 (MKK3), an upstream activator of p38α, had similar effects. Conversely, active MKK3 and MKK6, both of which increase p38α activity, each decreased transcription from the cyclin D1 promoter. Together, these data demonstrate that p38 negatively regulates cyclin D1 expression. We tested whether p38 regulates cyclin D1 expression via inhibition of extracellular signal-regulated kinase (ERK) activation. Chemical inhibitors of p38 induced modest ERK phosphorylation and activation. However, dominant negative MKK3 was insufficient to activate ERK, and active MKK3 and MKK6 did not attenuate platelet-derived growth factor-mediated ERK activation. These data are consistent with the notion that p38α negatively regulates cyclin D1 expression via an ERK-independent pathway.


2009 ◽  
Vol 202 (2) ◽  
pp. 309-316 ◽  
Author(s):  
Keisuke Ishizawa ◽  
Narantungalag Dorjsuren ◽  
Yuki Izawa-Ishizawa ◽  
Rika Sugimoto ◽  
Yasumasa Ikeda ◽  
...  

Adiponectin, an adipocyte-derived hormone, has been involved in metabolic syndrome, a known risk factor for the development of chronic kidney disease (CKD). Recent studies have demonstrated that plasma adiponectin levels are elevated when kidney function declines in patients with CKD. Excessive mesangial cell (MC) turnover is one of the important features of CKD. The aim of the present study is to elucidate the effects of adiponectin on platelet-derived growth factor (PDGF)-induced cell migration and intracellular signaling pathways, in cultured rat MCs (RMCs). PDGF-induced RMC migration was significantly inhibited by the pretreatment of adiponectin. Adiponectin alone had no effect on RMC migration. Big mitogen-activated protein (MAP) kinase 1 (BMK1), p38 MAP kinase, and Akt were activated by PDGF stimulation in a time- and concentration-dependent manner in RMC. Adiponectin alone did not affect BMK1, p38 MAP kinase, and Akt phosphorylations in RMC. PDGF-induced BMK1 and p38 MAP kinase phosphorylations were significantly attenuated by the pretreatment of adiponectin in RMCs. On the other hand, the phosphorylation of Akt by PDGF was not diminished by the pretreatment of adiponectin. Adiponectin had no effects on PDGF-receptor autophosphorylation by PDGF. We also confirmed that PDGF-induced RMC migration was significantly suppressed by siBMK1 transfection or SB203580, a p38 MAP kinase inhibitor. From these findings, it is implied that the elevated plasma adiponectin levels in patients with CKD might play a compensatory role aimed at counteracting renal dysfunction related to MC disorders.


2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
Shinji Takai ◽  
Rie Matsushima-Nishiwaki ◽  
Seiji Adachi ◽  
Hideo Natsume ◽  
Chiho Minamitani ◽  
...  

We previously showed that the mitogen-activated protein (MAP) kinase superfamily, p44/p42 MAP kinase, p38 MAP kinase, and stress-activated protein kinase (SAPK)/c-JunN-terminal (JNK), positively plays a part in the platelet-derived growth factor-BB- (PDGF-BB-) stimulated synthesis of interleukin-6 (IL-6), a potent bone resorptive agent, in osteoblast-like MC3T3-E1 cells while Akt and p70 S6 kinase negatively regulates the synthesis. In the present study, we investigated whether (-)-epigallocatechin gallate (EGCG), one of the major green tea flavonoids, affects the synthesis of IL-6 in these cells and the mechanism. EGCG significantly reduced the IL-6 synthesis and IL-6 mRNA expression stimulated by PDGF-BB, EGCG reduced the PDGF-BB-stimulated IL-6 synthesis also in primary-cultured osteoblasts. EGCG had no effect on the levels of osteocalcin and osteoprotegerin in MC3T3-E1 cells. The PDGF-BB-induced autophosphorylation of PDGF receptorβwas not suppressed by EGCG. The PDGF-BB-induced phosphorylation of p44/p42 MAP kinase and p38 MAP kinase was not affected by EGCG. On the other hand, EGCG markedly suppressed the PDGF-BB-induced phosphorylation of SAPK/JNK. Finally, the PDGF-BB-induced phosphorylation of Akt and p70 S6 kinase was not affected by EGCG. These results strongly suggest that EGCG inhibits the PDGF-BB-stimulated synthesis of IL-6 via suppression of SAPK/JNK pathway in osteoblasts.


2006 ◽  
Vol 207 (1) ◽  
pp. 123-131 ◽  
Author(s):  
Francesca Romano ◽  
Claudia Chiarenza ◽  
Fioretta Palombi ◽  
Antonio Filippini ◽  
Fabrizio Padula ◽  
...  

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Gen Kuroyanagi ◽  
Go Sakai ◽  
Takanobu Otsuka ◽  
Naohiro Yamamoto ◽  
Kazuhiko Fujita ◽  
...  

Abstract Background Heat shock protein 22 (HSP22) belongs to class I of the small HSP family that displays ubiquitous expression in osteoblasts. We previously demonstrated that prostaglandin F2α (PGF2α), a potent bone remodeling factor, induces the synthesis of interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) via p44/p42 mitogen-activated protein (MAP) kinase and p38 MAP kinase in osteoblast-like MC3T3-E1 cells. In the present study, we investigated whether HSP22 is implicated in the PGF2α-induced synthesis of IL-6 and VEGF and the mechanism of MC3T3-E1 cells. Methods MC3T3-E1 cells were transfected with HSP22-siRNA. IL-6 and VEGF release was assessed by ELISA. Phosphorylation of p44/p42 MAP kinase and p38 MAP kinase was detected by Western blotting. Results The PGF2α-induced release of IL-6 in HSP22 knockdown cells was significantly suppressed compared with that in the control cells. HSP22 knockdown also reduced the VEGF release by PGF2α. Phosphorylation of p44/p42 MAP kinase and p38 MAP kinase was attenuated by HSP22 downregulation. Conclusions Our results strongly suggest that HSP22 acts as a positive regulator in the PGF2α-induced synthesis of IL-6 and VEGF in osteoblasts.


PLoS ONE ◽  
2015 ◽  
Vol 10 (3) ◽  
pp. e0120774 ◽  
Author(s):  
Miyuki Inoue-Mochita ◽  
Toshihiro Inoue ◽  
Tomokazu Fujimoto ◽  
Takanori Kameda ◽  
Nanako Awai-Kasaoka ◽  
...  

2015 ◽  
Vol 309 (7) ◽  
pp. C491-C500 ◽  
Author(s):  
Samantha Gardner ◽  
Sean M. Gross ◽  
Larry L. David ◽  
John E. Klimek ◽  
Peter Rotwein

The p38 MAP kinases play critical roles in skeletal muscle biology, but the specific processes regulated by these kinases remain poorly defined. Here we find that activity of p38α/β is important not only in early phases of myoblast differentiation, but also in later stages of myocyte fusion and myofibrillogenesis. By treatment of C2 myoblasts with the promyogenic growth factor insulin-like growth factor (IGF)-I, the early block in differentiation imposed by the p38 chemical inhibitor SB202190 could be overcome. Yet, under these conditions, IGF-I could not prevent the later impairment of muscle cell fusion, as marked by the nearly complete absence of multinucleated myofibers. Removal of SB202190 from the medium of differentiating myoblasts reversed the fusion block, as multinucleated myofibers were detected several hours later and reached ∼90% of the culture within 30 h. Analysis by quantitative mass spectroscopy of proteins that changed in abundance following removal of the inhibitor revealed a cohort of upregulated muscle-enriched molecules that may be important for both myofibrillogenesis and fusion. We have thus developed a model system that allows separation of myoblast differentiation from muscle cell fusion and should be useful in identifying specific steps regulated by p38 MAP kinase-mediated signaling in myogenesis.


2017 ◽  
Vol 44 (3) ◽  
pp. 1133-1145 ◽  
Author(s):  
Go Sakai ◽  
Haruhiko Tokuda ◽  
Kazuhiko Fujita ◽  
Shingo Kainuma ◽  
Tetsu Kawabata ◽  
...  

Background/Aims: We previously demonstrated that transforming growth factor-β (TGF-β) stimulates the synthesis of vascular endothelial growth factor (VEGF) through the activation of p38 mitogen-activated protein (MAP) kinase in osteoblast-like MC3T3-E1 cells. Heat shock protein70 (HSP70) is a ubiquitously expressed molecular chaperone. In the present study, we investigated the involvement of HSP70 in the TGF-β-stimulated VEGF synthesis and the underlying mechanism in these cells. Methods: Culture MC3T3-E1 cells were stimulated by TGF-β. Released VEGF was measured using an ELISA assay. VEGF mRNA level was quantified by RT-PCR. Phosphorylation of each protein kinase was analyzed by Western blotting. Results: VER-155008 and YM-08, both of HSP70 inhibitors, significantly amplified the TGF-β-stimulated VEGF release. In addition, the expression level of VEGF mRNA induced by TGF-β was enhanced by VER-155008. These inhibitors markedly strengthened the TGF-β-induced phosphorylation of p38 MAP kinase. The TGF-β-induced phosphorylation of p38 MAP kinase was amplified in HSP70-knockdown cells. SB203580, an inhibitor of p38 MAP kinase, significantly suppressed the amplification by these inhibitors of the TGF-β-induced VEGF release. Conclusion: These results strongly suggest that HSP70 acts as a negative regulator in the TGF-β-stimulated VEGF synthesis in osteoblasts, and that the inhibitory effect of HSP70 is exerted at a point upstream of p38 MAP kinase.


Sign in / Sign up

Export Citation Format

Share Document