Original Paper

Aquaporin 1: Examination of Its Expression and Localization in Normal Human Skeletal Muscle Tissue
Takahiro Jimi^a, Yoshihiro Wakayama^a, Masahiko Inoue^a, Hiroko Kojima^a, Hiroaki Oniki^b, Yoko Matsuzaki^c, Seiji Shibuya^a, Hajime Hara^a, Joji Takahashi<sup>a

a</sup>Department of Neurology,
^bElectron Microscopic Laboratory and
^cBiochemical Laboratory, Showa University Fujigaoka Hospital, Yokohama, Japan

Address of Corresponding Author

Cells Tissues Organs 2006;184:181-187 (DOI: 10.1159/000099625)

  Key Words

• Aquaporins
• Human skeletal muscle
• Immunoblot
• Immunoelectron microscopy
• Immunohistochemistry
• Reverse transcription-polymerase chain reaction

  Abstract

To examine aquaporin 1 (AQP1) expression in skeletal muscle tissue precisely, we performed reverse transcription-polymerase chain reaction (RT-PCR) at RNA level and immunoblot analysis, immunohistochemistry and immunoelectron microscopy at protein level. The RT-PCR study of total RNA from normal human skeletal muscle showed a strong single band of AQP1. At the protein level we used two commercially available antibodies, both of which recognize the cytoplasmic domain of the AQP1 molecule. One antibody gave positive results. Immunoblot of muscle extract showed a 30-kDa band protein, the molecular weight of which corresponded to that of AQP1. Immunohistochemically, AQP1 was immunostained at the myofiber surface both in type 1 and type 2 myofibers with almost the same intensity, and its staining pattern was rather diffuse and irregular compared with that of the anti-dystrophin antibody. The endomysial endothelial cells were also immunolabeled. Immunoelectron microscopy revealed that the immunogold particles indicating the presence of the AQP1 molecule were present along the inside surface of the muscle plasma membrane. However, another antibody showed negative results except for the endomysial endothelial cells which were positively stained. We drew the conclusion that AQP1 is expressed at the endomysial capillary endothelial cell and further AQP1 may be expressed at the human skeletal myofiber plasma membrane.

Copyright © 2007 S. Karger AG, Basel

  Author Contacts

Prof. Yoshihiro Wakayama
Department of Neurology, Showa University Fujigaoka Hospital
1-30 Fujigaoka, Aoba-ku, Yokohama, 227-8501 (Japan)
Tel. +81 45 974 6269, Fax +81 45 974 2204
E-Mail wakayama@showa-university-fujigaoka.gr.jp

  Article Information

Accepted after revision: December 28, 2006
Number of Print Pages : 7
Number of Figures : 4, Number of Tables : 0, Number of References : 16