Aquaporin 9 expression and its localization in normal skeletal myofiber

Inoue, Masahiko; Wakayama, Yoshihiro; Kojima, Hiroko; Shibuya, Seiji; Jimi, Takahiro; Hara, Hajime; Iijima, Satoshi; Masaki, Hisatsugu; Oniki, Hiroaki; Matsuzaki, Yoko

doi:10.1007/s10735-009-9226-1

Cited by 16 publications

(20 citation statements)

References 24 publications

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“…The discrepant expression of AQP7 in the ob/ob mouse skeletal muscle and the adipose tissue of human diet induced obese subjects may be explained by the action of leptin which downregulates AQP7. The present studies confirmed our previous study [14] that the AQP9 was also expressed on the surface membrane of murine skeletal myofibers, especially in type 2 myofibers, although the expression level was not significantly different in the skeletal muscles between obese ob/ob mice and wild mice. Although AQP is suggested to be regulated by leptin through the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin pathway in visceral adipocytes and hepatocytes [28], AQP7 may be more influenced by this pathway than AQP9 in the skeletal muscle.…”

Section: Discussionsupporting

confidence: 92%

“…General procedures for peptide syntheses and antibody production were similar to those described previously [14, 39]. Briefly, the peptide (MVQASGHRRSTRGSK-C) of the N-terminal end of the cytoplasmic domain in the human AQP7 molecule (Entrez NM001170) and the peptide (KAEQSEDKPEKYE-C) of the C-terminal end of the cytoplasmic domain in the human AQP9 molecule (Entrez NM020980) were synthesized and the extra cysteine was added to the C-terminus of AQP7 and AQP9 molecules.…”

Section: Methodsmentioning

confidence: 99%

“…AQP7-deficient mice have been reported to lead to obesity [12, 13, 22], while AQP9 deletion leads to the onset of diabetes mellitus [29]. We have so far been analyzing the expression of AQPs3, 7 and 9 in human skeletal muscles and AQP7 in mouse skeletal muscles [14, 38, 39]. These three AQPs in the human skeletal muscles and AQP7 in the mouse skeletal muscles were found to be expressed at the myofiber surface of the skeletal muscle tissues, although the contradictory result has been reported with respect to AQP7 [32].…”

Section: Introductionmentioning

confidence: 99%

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Upregulated Expression of AQP 7 in the Skeletal Muscles of Obese ob/ob Mice

Wakayama

Hirako

Ogawa

et al. 2014

Acta Histochem. Cytochem

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Aquaporin (AQP) is suggested to be regulated by leptin through the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin pathway. AQP7 and AQP9 are membrane proteins with water and glycerol channels, the latter of which is essential for triglyceride synthesis. We conjectured that the expression of AQP7 and AQP9 would be altered in the skeletal myofibers in obese leptin deficient ob/ob mice as compared with that of wild mice. RNA and protein levels were studied in the quadriceps femoris muscles of ob/ob and wild mice. Real time quantitative RT-PCR analysis showed that mouse AQP7 mRNA levels in skeletal muscles were significantly higher in ob/ob mice than in wild mice (P<0.01), whereas mouse AQP9 mRNA level was not different between the two groups (P>0.05). Histologically the type 1 myofibers of ob/ob mice contained numerous lipid droplets in oil red O stain samples. Immunohistochemical staining of ob/ob mouse muscles revealed enhanced expression of AQP7 at myofiber surface membranes, while AQP9 expression appeared to be similar to that of wild mice. The findings suggest that the upregulated expression of AQP7 in ob/ob mouse muscles facilitates the secretion of glycerol from myocytes.

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Section: Discussionsupporting

confidence: 92%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Upregulated Expression of AQP 7 in the Skeletal Muscles of Obese ob/ob Mice

Wakayama

Hirako

Ogawa

et al. 2014

Acta Histochem. Cytochem

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“…The previously described general procedures were used for peptide syntheses and antibody production [16,17]. Briefly, the peptide (MVQASGHRRSTRGSK-C) of the N-terminal end of the cytoplasmic domain in the human AQP7 molecule (Entrez NM001170) and the peptide (KAEQSEDKPEKYE-C) of the C-terminal end of the cytoplasmic domain in the human AQP9 molecule (Entrez NM020980) were respectively synthesized and the extra cysteine was added to the C-terminus of AQP7 and AQP9 molecules.…”

Section: Peptide Synthesis and Antibody Productionmentioning

confidence: 99%

AQP7 Up-Regulation in the Skeletal Muscles of Mice with Diet Induced Obesity

Wakayama¹

2015

J Cell Sci Ther

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Aquaporin (AQP) 7 and AQP9 are membrane proteins and are the members of aquaglyceroporin which transports glycerol in addition to water molecule. Glycerol is a direct source of glycerol-3 phosphate for the synthesis of triglycerides. We thought that the expression of AQP7 and AQP9 would be altered in the skeletal myofibers in mice with diet-induced obesity (DIO) as compared with that of control chaw-fed mice. RNA and protein levels of AQP7 and AQP9 were studied in the quadriceps femoris muscles of mice with DIO and normal control mice. Real time quantitative RT-PCR analysis showed that mouse AQP7 mRNA levels in skeletal muscles were significantly higher in mice with DIO than in normal control mice (P<0.01); whereas mouse AQP9 mRNA levels were not different between the two groups (P>0.05). Histochemically the myofibers of mice with DIO contained numerous lipid droplets in oil red O stain samples. Immunohistochemical study of DIO mouse muscles showed enhanced expression of AQP7 at the myofiber surface membranes; while AQP9 expression appeared to be similar to that of normal control mice. These findings imply that the up-regulated expression of AQP7 in DIO mouse muscles facilitates the secretion of glycerol from myocytes.

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“…In these original reports, AQP9 mRNA expression was found in a few tissues, most notably liver and leukocytes in humans (Ishibashi et al 1998;Tsukaguchi et al 1999), as well as liver and immature sperm in mice (Tsukaguchi et al 1998). Since then, AQP9 immunoreactivity has been found in many tissues, including rat and human epididymis (Elkjaer et al 2000;Pastor-Soler et al 2001), various cell types of rodent and primate brain (Elkjaer et al 2000;Badaut et al 2001;Badaut et al 2004;Amiry-Moghaddam et al 2005;Arcienega et al 2010), mouse spinal cord (Oshio et al 2004), human chorioamnion and placenta (Damiano et al 2001;Wang et al 2004), mouse and human inner ear (Huang et al 2002;Degerman et al 2011), mouse and human small intestine (Okada et al 2003), rat and human prostate (Wang et al 2008;Hwang et al 2012), human skeletal muscle (Inoue et al 2009), urothelium (Rubenwolf et al 2009), rat and porcine oviduct (Skowronski et al 2009), human adipose tissue (Rodriguez et al 2011), human retina (Tran et al 2013;Yang et al 2013), and mouse and human skin (Sugiyama et al 2014). …”

Section: Introductionmentioning

confidence: 99%

A Systematic Characterization of Aquaporin-9 Expression in Human Normal and Pathological Tissues

Lindskog

Asplund

Catrina

et al. 2016

J Histochem Cytochem.

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SummaryAQP9 is known to facilitate hepatocyte glycerol uptake. Murine AQP9 protein expression has been verified in liver, skin, epididymis, epidermis and neuronal cells using knockout mice. Further expression sites have been reported in humans. We aimed to verify AQP9 expression in a large set of human normal organs, different cancer types, rheumatoid arthritis synovial biopsies as well as in cell lines and primary cells. Combining standardized immunohistochemistry with high-throughput mRNA sequencing, we found that AQP9 expression in normal tissues was limited, with high membranous expression only in hepatocytes. In cancer tissues, AQP9 expression was mainly found in hepatocellular carcinomas, suggesting no general contribution of AQP9 to carcinogenesis. AQP9 expression in a subset of rheumatoid arthritis synovial tissue samples was affected by Humira, thereby supporting a suggested role of TNFα in AQP9 regulation in this disease. Among cell lines and primary cells, LP-1 myeloma cells expressed high levels of AQP9, whereas low expression was observed in a few other lymphoid cell lines. AQP9 mRNA and protein expression was absent in HepG2 hepatocellular carcinoma cells. Overall, AQP9 expression in human tissues appears to be more selective than in mice. (J Histochem Cytochem 64:287-300, 2016)

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Aquaporin 9 expression and its localization in normal skeletal myofiber

Cited by 16 publications

References 24 publications

Upregulated Expression of AQP 7 in the Skeletal Muscles of Obese ob/ob Mice

Upregulated Expression of AQP 7 in the Skeletal Muscles of Obese ob/ob Mice

AQP7 Up-Regulation in the Skeletal Muscles of Mice with Diet Induced Obesity

A Systematic Characterization of Aquaporin-9 Expression in Human Normal and Pathological Tissues

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