Aquaporin 4: lack of mRNA expression in the rat regenerating muscle fiber under denervation

Jimi, Takahiro; Wakayama, Yoshihiro; Murahashi, Makoto; Shibuya, Seiji; Inoue, Masahiko; Hara, Hajime; Matsuzaki, Yoko; Uemura, Norie

doi:10.1016/s0304-3940(00)01382-3

Cited by 22 publications

(16 citation statements)

References 19 publications

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“…In this context, muscles of patients with FCMD may have faulty motor nerve innervation. The decreased amounts of AQP4 and AQP4 mRNA in FCMD muscles may be due to the dysinnervation of skeletal muscles in FCMD, since lack of AQP4 mRNA after denervation has been reported [11]. Alternatively, many patients with FCMD are very young and their muscle biopsies contain the immature and regenerating myofibers.…”

Section: Discussionmentioning

confidence: 99%

Altered aquaporin 4 expression in muscles of Fukuyama-type congenital muscular dystrophy

et al. 2003

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This study was undertaken to investigate the expression of aquaporin 4 (AQP4) in the muscle plasma membrane of children with Fukuyama-type congenital muscular dystrophy (FCMD) at protein and mRNA levels. The biopsied six muscles with FCMD, six histochemically normal muscles and eight disease control muscles were analyzed by means of immunoblots, immunohistochemistry and reverse-transcription polymerase chain reaction (RT-PCR). Immunoblots showed that the band of FCMD muscle extracts stained with anti-AQP4 antibody was faint in comparison with that of normal muscle extracts. The immunohistochemistry revealed that most of the FCMD myofibers showed negative immunostaining with anti-AQP4 antibody, although the partially positive immunostaining of sporadic FCMD myofibers was noted. The immunoreactivity was positive with anti-dystrophin and anti-beta-spectrin antibodies in almost all FCMD myofibers. The quantitative RT-PCR demonstrated that the AQP4 mRNA level of the FCMD muscles was markedly reduced. On the basis of these findings, we conclude that the expression of AQP4 in FCMD myofibers is reduced and the reduced content of AQP4 mRNA in FCMD muscles may be related to the decreased expression of AQP4 at the muscle plasma membrane of FCMD myofibers.

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Section: Discussionmentioning

confidence: 99%

Altered aquaporin 4 expression in muscles of Fukuyama-type congenital muscular dystrophy

et al. 2003

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“…To explore further functional roles of AQP7 in skeletal muscles, studies on the following issues may be necessary: (1) the factor that influences the expression of AQP7 in skeletal muscle, for example, as AQP4 expression is controlled by the influence of nerves (Jimi et al 2000), does denervation influence the expression of AQP7? (2) The AQP7 expression of muscle cells in a physiologic condition, such as muscle cell development or regeneration.…”

Section: Discussionmentioning

confidence: 99%

“…AQP4 in skeletal muscle has been extensively studied (Frigeri et al 1998(Frigeri et al , 2001(Frigeri et al , 2002Liu et al 1999;Jimi et al 2000;Wakayama et al 2001Wakayama et al , 2002a. The reduced expression of AQP4 in the muscles of boys with Duchenne dystrophy (Frigeri et al 2002;Wakayama et al 2002a) and of mdx mice (Liu et al 1999;Frigeri et al 2001;Crosbie et al 2002) has been described.…”

Section: Introductionmentioning

confidence: 99%

Expression and localization of aquaporin 7 in normal skeletal myofiber

Wakayama

Inoue

Kojima

et al. 2004

Cell and Tissue Research

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We examined whether AQP7 molecules are expressed in the normal skeletal muscle at mRNA and protein levels. Gel electrophoresis of the reverse transcription-polymerase chain reaction (RT-PCR) product of total RNA samples of normal human or mouse muscles by using oligonucleotide primers for human or mouse AQP7 showed a band of 328 or 369 basepairs, which corresponded to the basepair length between two primers of AQP7. The nucleotide sequence of these RT-PCR products coincided with those of human and mouse AQP7. Immunoblot, immunohistochemical and immunoelectron-microscopic studies of the protein were done by using the rabbit antibody against the synthetic peptide of the N-terminal cytoplasmic domain of the human AQP7 molecule. Immunoblot analysis showed that the rabbit antibody against human AQP7 reacted with a protein of approximately 30 kDa molecular weight in extracts of normal human and mouse skeletal muscles, and normal mouse liver. Immunohistochemistry with our anti-AQP7 antibody showed an immunoreaction at the myofiber surface of type 1 and type 2 fibers in human muscles and of type 2 fibers in mouse muscles.

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“…In addition, the freeze-fracture study of the experimentally denervated regenerating myofibers showed no OA particles at their muscle plasma membrane P face, 30 and the mRNA of AQP4 molecule was absent in these muscles. 31 Further investigations on the mechanism of the decrease of AQP4 mRNA in DMD muscles will throw light onto the mechanism of the depletion of OA particles, DMD muscle membrane lysis causing high serum levels of sarcoplasmic enzymes and the formation of delta lesions of DMD myofibers, and finally the dysfunction and degeneration of DMD muscles. In muscles from patients with Duchenne muscular dystrophy (DMD), AQP4 mRNA level was markedly decreased.…”

Section: Commentmentioning

confidence: 99%

Reduced Aquaporin 4 Expression in the Muscle Plasma Membrane of Patients With Duchenne Muscular Dystrophy

Wakayama

Jimi²,

Inoue³

et al. 2002

Arch Neurol

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Aquaporin 4: lack of mRNA expression in the rat regenerating muscle fiber under denervation

Cited by 22 publications

References 19 publications

Altered aquaporin 4 expression in muscles of Fukuyama-type congenital muscular dystrophy

Altered aquaporin 4 expression in muscles of Fukuyama-type congenital muscular dystrophy

Expression and localization of aquaporin 7 in normal skeletal myofiber

Reduced Aquaporin 4 Expression in the Muscle Plasma Membrane of Patients With Duchenne Muscular Dystrophy

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