Volume 14, Issue 3 pp. 165-176

Activation of MAP kinases, Akt and PDGF receptors in injured peripheral nerves

Takashi Yamazaki

Takashi Yamazaki

Departments of Pathology

Oral and Maxillofacial Surgery, Graduate School of Medicine and Pharmaceutical Sciences for Research, University of Toyama, Toyama

These authors contributed equally to this work.

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Hemragul Sabit

Hemragul Sabit

Departments of Pathology

These authors contributed equally to this work.

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Takeshi Oya

Takeshi Oya

Departments of Pathology

Core Research for Evolutional Science and Technology, Japan Science and Technology Agency (CREST, JST), Kawaguchi, Japan

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Yoko Ishii

Yoko Ishii

Departments of Pathology

Core Research for Evolutional Science and Technology, Japan Science and Technology Agency (CREST, JST), Kawaguchi, Japan

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Takeru Hamashima

Takeru Hamashima

Departments of Pathology

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Ayano Tokunaga

Ayano Tokunaga

Departments of Pathology

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Shin Ishizawa

Shin Ishizawa

Departments of Pathology

Core Research for Evolutional Science and Technology, Japan Science and Technology Agency (CREST, JST), Kawaguchi, Japan

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Shen Jie

Shen Jie

Departments of Pathology

Core Research for Evolutional Science and Technology, Japan Science and Technology Agency (CREST, JST), Kawaguchi, Japan

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Yoichi Kurashige

Yoichi Kurashige

Departments of Pathology

Core Research for Evolutional Science and Technology, Japan Science and Technology Agency (CREST, JST), Kawaguchi, Japan

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Takako Matsushima

Takako Matsushima

Departments of Pathology

Core Research for Evolutional Science and Technology, Japan Science and Technology Agency (CREST, JST), Kawaguchi, Japan

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Isao Furuta

Isao Furuta

Oral and Maxillofacial Surgery, Graduate School of Medicine and Pharmaceutical Sciences for Research, University of Toyama, Toyama

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Makoto Noguchi

Makoto Noguchi

Oral and Maxillofacial Surgery, Graduate School of Medicine and Pharmaceutical Sciences for Research, University of Toyama, Toyama

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Masakiyo Sasahara

Corresponding Author

Masakiyo Sasahara

Departments of Pathology

Core Research for Evolutional Science and Technology, Japan Science and Technology Agency (CREST, JST), Kawaguchi, Japan

Masakiyo Sasahara, Department of Pathology, Graduate School of Medicine and Pharmaceutical Sciences for Research, University of Toyama, Sugitani 2630, Toyama, 930-0194 Japan. Tel: 81-76-434-7238; Fax: 81-76-434-5016. E-mail: [email protected]Search for more papers by this author
First published: 10 November 2009
Citations: 53

Abstract

A number of receptor tyrosine kinases (RTKs) and the downstream phosphatidylinositol-3-kinase (PI3K)/Akt and mitogen-activated protein (MAP) kinase signaling pathways have been critically involved in peripheral nerve regeneration. Here, we examined the activation of PI3K/Akt and MAP kinase pathways, and platelet-derived growth factor receptors (PDGFRs) in the distal segments of crushed rat sciatic nerve from 3 to 28 days after injury. In Western blot analyses, the phosphorylated forms of extracellular signal-regulated protein kinase (ERK) and c-Jun NH2-terminal kinases (JNKs) were highly augmented on days 3 and 7 and on days 7 and 14 after injury, respectively. Phosphorylated Akt and p38 consistently increased from 3 to 28 days after injury. Phosphorylated PDGFR-α and -β were also increased from 3 to 14 days. In the immunohistological analyses, phosphorylated ERK and PDGFR-α were co-localized in many activated Schwann cells and regrowing axons 3 days after injury, while PDGFR-β was localized in a few spindle-shaped cells. The detected temporal profile of RTK signaling appears to be crucial for the regulation of Schwann cell proliferation and following redifferentiation. Furthermore, the immunohistological studies suggested a role of ERK and PDGFR-α in axon regeneration as well.

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