Protein Kinase C-δ Transactivates Platelet-derived Growth Factor Receptor-α in Mechanical Strain-induced Collagenase 3 (Matrix Metalloproteinase-13) Expression by Osteoblast-like Cells

Yang, Che‐Hua; Hsieh, Hsi‐Lung; Yao, Chung-Chen Jane; Hsiao, Li-Der; Tseng, Ching Ping; Wu, Chuansha

doi:10.1074/jbc.m109.040154

Cited by 12 publications

(7 citation statements)

References 40 publications

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“…These differences likely reflect differences in not only cell type but also the nature of the stimulus. A further observation that PKCδ is required for mechanotransduced PI3K-Akt and ERK1/2 activation seems consistent with the reports of PKC interactions with PI3K-Akt and ERK1/2 in other cell types [48,49]. However, this relationship has not been investigated in chondrocytes under mechanical stimulation.…”

Section: Discussionsupporting

confidence: 75%

Periodic Mechanical Stress Activates PKCδ-Dependent EGFR Mitogenic Signals in Rat Chondrocytes via PI3K-Akt and ERK1/2

Shen

Gao

et al. 2016

Cell Physiol Biochem

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Background/Aims: The present study aimed to analyze the mechanisms by which periodic mechanical stress is translated into biochemical signals, and to verify the important role of signaling molecules including phosphatidylinositol-3-kinase (PI3K)-Akt, protein kinase C (PKC), and epidermal growth factor receptor (EGFR) in chondrocyte proliferation. The effects of periodic mechanical stress on the mitogenesis of chondrocytes have been studied extensively in recent years. However, the mechanisms underlying the ability of chondrocytes to sense and respond to periodic mechanical stress need further investigation. Methods: Two steps were undertaken in the experiment. In the first step, the cells were pretreated with shRNA targeted to Akt or EGFR or PKCδ or control scrambled shRNA. Moreover, they were pretreated with LY294002, GF109203X, Gö6976, rottlerin, and AG1478. They were maintained under static conditions or periodic mechanical stress for 3 days, 8 h per day, prior to direct cell counting and CCK-8 assay, respectively. In the second step, the cells were pretreated with shRNA targeted to Akt or EGFR or PKCδ or control scrambled shRNA. Moreover, they were pretreated with LY294002, AG1478, and rottlerin. They were maintained under static conditions or periodic mechanical stress for 1 h prior to Western blot analysis. Results: Proliferation was inhibited by pretreatment with PKC or PKCδ inhibitor GF109203X or rottlerin and by short hairpin RNA (shRNA) targeted to PKCδ, but not by PKCα inhibitor Gö6976 in chondrocytes in response to periodic mechanical stress. Meantime, rottlerin and shRNA targeted to PKCδ also attenuated EGFR, Akt, and ERK1/2 activation. Furthermore, inhibiting EGFR activity by AG1478 and shRNA targeted to EGFR abrogated chondrocyte proliferation and phosphorylation levels of Akt and extracellular signal-regulated kinase (ERK)1/2 subjected to periodic mechanical stress, while the phosphorylation site of PKCδ was not affected. In addition, pretreatment with the PI3K-Akt-selective inhibitor LY294002 and shRNA targeted to Akt reduced periodic mechanical stress-induced chondrocyte proliferation and phosphorylation of ERK1/2, while the phosphorylation levels of EGFR and PKCδ were not inhibited. Conclusion: These findings suggested that periodic mechanical stress promoted chondrocyte proliferation through PKCδ-EGFR-PI3K-Akt-ERK1/2. They provide a stronger viewpoint for further investigations into chondrocyte mechanobiology under periodic mechanical stress and the ways to improve the quality of tissue-engineered cartilage.

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Section: Discussionsupporting

confidence: 75%

Periodic Mechanical Stress Activates PKCδ-Dependent EGFR Mitogenic Signals in Rat Chondrocytes via PI3K-Akt and ERK1/2

Shen

Gao

et al. 2016

Cell Physiol Biochem

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“…29 In mouse osteoblasts, PI3K/Akt appears to be involved in PKCd-regulated MMP-13 expression. 17 In addition, a recently published report suggests that PI3K/Akt may be upstream of ERK for macrophage polarization in mice bone marrow-derived macrophages. 30 The present study clearly delineated the relationship among PKCd, PI3K/Akt, and ERK signalling pathways in regulating foam cell formation: both PI3K/Akt and ERK were downstream signaling molecules of PKCd and PI3K/Akt acted as an upstream regulator of ERK.…”

Section: Pathways Previous Studies In Apoementioning

confidence: 99%

“…It has been suggested that phosphatidylinositol 3-kinase (PI3K)/Akt is involved in PKCd-regulated matrix metalloproteinase-13 (MMP-13) expression in primary mouse osteoblasts. 17 To clarify whether PI3K/Akt is involved in PKCd-regulated expression of SRs, we examined the effects of a PI3K/Akt inhibitor LY294002. We showed that the inhibition of PI3K/Akt significantly reduced SR-A, CD36, and p-ERK expression ( Figure 2C).…”

Section: Differential Involvement Of Erk and Pi3k/akt Pathways In Pkcmentioning

confidence: 99%

PKCδ signalling regulates SR-A and CD36 expression and foam cell formation

Lin

et al. 2012

Cardiovascular Research

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AimsThe formation of foam cells is crucial in the initiation and progression of atherosclerosis. One of the critical steps in foam cell formation is the uptake of low-density lipoprotein (LDL) by macrophages via scavenger receptors (SRs). This study examined the role of protein kinase C (PKC) isoforms on foam cell formation. Methods and resultsThe effects of short-hairpin RNA (shRNA) and small interfering RNA (siRNA) against classical PKC and novel PKC isoforms were investigated in THP-1-derived macrophages and primary macrophages. The knockdown of PKCd inhibited oxidized LDL (OxLDL) uptake and intracellular cholesterol accumulation in both cell models. The reduction of PKCd resulted in decreased expression of SR-A and CD36. Similar conclusions were obtained in examining the effects of a PKCd inhibitor, rottlerin. Molecular investigation revealed that a decrease in PKCd inhibited protein kinase B (PKB/Akt) expression and extracellular-signal-regulated kinase (ERK) phosphorylation. Surprisingly, PKCdknockdown selectively decreased protein but not the mRNA level of PKCbI and PKCbII. We showed that the inhibition of phosphatidylinositol 3-kinase (PI3K)/Akt upstream of ERK decreased SR-A and CD36 expression; however, the inhibition of ERK or PKCb downstream of ERK attenuated SR-A but not CD36 expression. We further demonstrated that PKCd could be induced by pro-atherogenic mediators, OxLDL and interferon-g. Notably, PKCd, phosphorylated ERK, Akt, and SR-A were highly expressed in human atherosclerotic arteries and CD68-positive macrophages as visualized by immunohistochemical staining. ConclusionThrough regulating PI3K/Akt and ERK activity, PKCd affects SR-A and CD36 expression and foam cell formation. The results suggest PKCd as a potential target for atherosclerosis therapeutics.--

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“…These results, together with the findings mentioned previously that a metalloproteinase and RTK inhibitor fail to block DPDPE‐induced ERK1/2 activation, indicate that Src activation may not be required for δ receptor‐mediated ERK1/2 activation by transactivating RTKs in response to morphine and TIPP. Because PKCδ has been shown to activate metalloproteinases and induce ectodomain shedding of the proheparin‐binding EGF‐like growth factor (proHB‐EGF) (Im et al ., ; Yang et al ., ; Kveiborg et al ., ), we next determined the effects of morphine, TIPP and DPDPE on PKCδ phosphorylation at serine 643. As shown in Figure D, treatment of HEK293 δ receptor cells with morphine (10 μM) or TIPP (1 μM), but not DPDPE (1 μM), induced a robust increase in PKCδ phosphorylation at serine 643, indicating that morphine and TIPP, but not DPDPE, activate PKCδ.…”

Section: Resultsmentioning

confidence: 99%

“…Although Src has been reported to link GPCR stimulation to the activatation of metalloproteinases and transactivation of EGFR (Daub et al ., ; Pierce et al ., ; Kim et al ., ; Noma et al ., ), it fails to activate metalloproteinases and transactivate EGFR upon stimulation of δ receptors with DPDPE, as metalloproteinase and EGFR inhibitors are unable to block DPDPE‐induced ERK1/2 activation. However, in contrast to previous findings that showed PKCδ induces ectodomain shedding of the proHB‐EGF by activating metalloproteinases (Im et al ., ; Yang et al ., ; Kveiborg et al ., ), we found that PKCδ activated by morphine or TIPP is able to induce metalloproteinase‐dependent release of HB‐EGF in the extracellular medium after δ receptor stimulation, leading to the transactivation of EGFR. Although HB‐EGF was not detected directly in the present study, it is clearly released in the medium of TIPP or morphine‐stimulated, δ receptor‐expressing cells, as small interfering RNA to PKCδ or inhibition of PKCδ activity by GF109203X inhibited TIPP‐ or morphine‐induced EGFR phosphorylation, and the transfer of supernatant from the δ receptor‐expressing donor cells led to EGFR‐dependent ERK1/2 activation in HEK293 cells devoid of endogenous δ receptors.…”

Section: Discussionmentioning

confidence: 99%

Role for engagement of β‐arrestin2 by the transactivated EGFR in agonist‐specific regulation of δ receptor activation of ERK1/2

Zhang

Wang

et al. 2015

British J Pharmacology

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BACKGROUND AND PURPOSEβ-Arrestins function as signal transducers linking GPCRs to ERK1/2 signalling either by scaffolding members of ERK1/2s cascades or by transactivating receptor tyrosine kinases through Src-mediated release of transactivating factor. Recruitment of β-arrestins to the activated GPCRs is required for ERK1/2 activation. Our previous studies showed that δ receptors activate ERK1/2 through a β-arrestin-dependent mechanism without inducing β-arrestin binding to the δ receptors. However, the precise mechanisms involved remain to be established. EXPERIMENTAL APPROACHERK1/2 activation by δ receptor ligands was assessed using HEK293 cells in vitro and male Sprague Dawley rats in vivo. Immunoprecipitation, immunoblotting, siRNA transfection, intracerebroventricular injection and immunohistochemistry were used to elucidate the underlying mechanism. KEY RESULTSWe identified a new signalling pathway in which recruitment of β-arrestin2 to the EGFR rather than δ receptor was required for its role in δ receptor-mediated ERK1/2 activation in response to H-Tyr-Tic-Phe-Phe-OH (TIPP) or morphine stimulation. Stimulation of the δ receptor with ligands leads to the phosphorylation of PKCδ, which acts upstream of EGFR transactivation and is needed for the release of the EGFR-activating factor, whereas β-arrestin2 was found to act downstream of the EGFR transactivation. Moreover, we demonstrated that coupling of the PKCδ/EGFR/β-arrestin2 transactivation pathway to δ receptor-mediated ERK1/2 activation was ligand-specific and the Ser 363 of δ receptors was crucial for ligand-specific implementation of this ERK1/2 activation pathway. CONCLUSIONS AND IMPLICATIONSThe δ receptor-mediated activation of ERK1/2 is via ligand-specific transactivation of EGFR. This study adds new insights into the mechanism by which δ receptors activate ERK1/2.Abbreviations DPDPE, [D-Pen2, D-Pen5] enkephalin; HB-EGF, heparin-binding EGF-like growth factor; IGFR, insulin-like growth factor receptor; NG108-15, cell mouse neuroblastoma x rat glioma hybrid cell; RTK, receptor tyrosine kinase; TIPP, H-Tyr-Tic-PhePhe-OH

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Protein Kinase C-δ Transactivates Platelet-derived Growth Factor Receptor-α in Mechanical Strain-induced Collagenase 3 (Matrix Metalloproteinase-13) Expression by Osteoblast-like Cells

Cited by 12 publications

References 40 publications

Periodic Mechanical Stress Activates PKCδ-Dependent EGFR Mitogenic Signals in Rat Chondrocytes via PI3K-Akt and ERK1/2

Periodic Mechanical Stress Activates PKCδ-Dependent EGFR Mitogenic Signals in Rat Chondrocytes via PI3K-Akt and ERK1/2

PKCδ signalling regulates SR-A and CD36 expression and foam cell formation

Role for engagement of β‐arrestin2 by the transactivated EGFR in agonist‐specific regulation of δ receptor activation of ERK1/2

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