Expression of aquaporin 1 (AQP1) water channels in human labial salivary glands

Gresz, Veronika

doi:10.1016/s0003-9969(99)00051-5

Cited by 9 publications

(13 citation statements)

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“…Acetylcholine acts on M3R on myoepithelial cells (Beroukas et al, 2002) and causes their contraction (Satoh et al, 1994). The presence of M3R (Beroukas et al, 2002) and AQP-1 (Gresz et al, 1999(Gresz et al, , 2001; present study) on salivary gland myoepithelial cells also raises the interesting possibility that some of the effects of acetylcholine on secretion may be mediated indirectly through an action on the myoepithelial cells rather than through a direct effect of acetylcholine on the acinar cells. Because myoepithelial cells embrace acini, they could constitute a barrier to water flow into the acinar cells; the presence of AQP-1 in myoepithelial cells might ensure that water flow into the basal aspect of the acinar epithelial cells is not restricted (Gresz et al, 2001).…”

Section: Role Of Aqp-1 and Myoepithelial Cells In Exocrine Gland Funcmentioning

confidence: 53%

Selective Down-Regulation of Aquaporin-1 in Salivary Glands in Primary Sjögren's Syndrome

Beroukas

Hiscock

Gannon

et al. 2002

Laboratory Investigation

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Section: Role Of Aqp-1 and Myoepithelial Cells In Exocrine Gland Funcmentioning

confidence: 53%

Selective Down-Regulation of Aquaporin-1 in Salivary Glands in Primary Sjögren's Syndrome

Beroukas

Hiscock

Gannon

et al. 2002

Laboratory Investigation

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“…Although not shown in the secretion model (Fig. 6), numerous aquaporin (AQP) water channels are expressed in human salivary glands (14,15,33). For example, AQP5 has been localized to the apical surface of human and rat salivary gland acinar cells (15,18,28), where it has been demonstrated to play an important part in stimulated transcellular water movement in mouse salivary glands (21,26).…”

Section: Discussionmentioning

confidence: 99%

Functional and molecular characterization of the fluid secretion mechanism in human parotid acinar cells

Nakamoto¹,

Srivastava²,

Romanenko³

et al. 2007

American Journal of Physiology-Regulatory, Integrative and Comp

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The strategies available for treating salivary gland hypofunction are limited because relatively little is known about the secretion process in humans. An initial microarray screen detected ion transport proteins generally accepted to be critically involved in salivation. We tested for the activity of some of these proteins, as well as for specific cell properties required to support fluid secretion. The resting membrane potential of human acinar cells was near -51 mV, while the intracellular [Cl-] was approximately 62 mM, about fourfold higher than expected if Cl ions were passively distributed. Active Cl- uptake mechanisms included a bumetanide-sensitive Na+ -K+ -2Cl- cotransporter and paired DIDS-sensitive Cl-/HCO3- and EIPA-sensitive Na+/H+ exchangers that correlated with expression of NKCC1, AE2, and NHE1 transcripts, respectively. Intracellular Ca2+ stimulated a niflumic acid-sensitive Cl- current with properties similar to the Ca2+ -gated Cl channel BEST2. In addition, intracellular Ca2+ stimulated a paxilline-sensitive and voltage-dependent, large-conductance K channel and a clotrimazole-sensitive, intermediate-conductance K channel, consistent with the detection of transcripts for KCNMA1 and KCNN4, respectively. Our results demonstrate that the ion transport mechanisms in human parotid glands are equivalent to those in the mouse, confirming that animal models provide valuable systems for testing therapies to prevent salivary gland dysfunction.

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“…Until recently, the pathway of water flow into salivary glands has been obscure, and both paracellular and transcellular pathways have been considered [24]. Recent evidence suggests, however, that salivary water flow into the acinar lumen might be, at least in part, transcellular as: (1) AQP plasma membrane water channels have been detected in acinar epithelia [9,10,11,14,22,26], and (2) defective saliva formation occurs in transgenic mice lacking the salivary AQP AQP5 [19]. In rat submandibular glands, AQP5 has been localized in the apical membranes of acinar and intercalated duct epithelial cells [9,11,22,26].…”

Section: Discussionmentioning

confidence: 99%

“…AQP1 is located in capillary endothelia [18], and is presumably involved in the transport of water from capillaries to salivary glands [18,20]. AQP1 is present in the basolateral membranes of human labial acinar cells [10]. AQP5 is localized in the apical membranes of submandibular [9,11,22,26] and parotid [14] acinar cells.…”

Section: Introductionmentioning

confidence: 99%

Evidence that aquaporin-8 is located in the basolateral membrane of rat submandibular gland acinar cells

Wellner

Hoque

Goldsmith

et al. 2000

Pflügers Arch - Eur J Physiol

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It is possible that, during primary saliva formation, aquaporins (AQPs) facilitate transcellular water flow across acinar cells to the lumina of salivary glands. In the rat submandibular gland (rSMG) AQP5 is localized in the apical membranes of acinar cells. The presence of a basolateral AQP in the same cell type has not been reported. We have therefore used immunofluorescence confocal microscopy to determine the subcellular localization of a newly discovered aquaporin, AQP8, in rSMG epithelial cells. The antibodies we used were made against the amino- or carboxyl-terminus (anti-rAQP8NT and anti-rAQP8CT, respectively) of an AQP8 cloned from rat pancreas and liver (rAQP8). Two lines of evidence suggest that both antibodies are suitable for immunolocalization studies. First, results of immunofluorescence confocal microscopy studies show that both antibodies bind to the plasma membranes of 293 cells infected with an adenovirus encoding rAQP8. Second, results of immunoblots of membranes from infected cells suggest that both antibodies bind to glycosylated and non-glycosylated forms of rAQP8. When tested in frozen sections of rSMG, we could not detect the binding of anti-rAQP8NT to any membranes. In contrast, anti-rAQP8CT binds to the basolateral membranes of acinar (but not ductal) epithelia, suggesting that rAQP8 resides in the basolateral membranes of acinar cells. Lack of anti-rAQPNT binding to basolateral membranes suggests that this epitope is not available in the membranes. Our evidence for the basolateral localization of rAQP8 in acinar cells, coupled with previous findings that AQP5 is localized apically in the same cells, raises the possibility that water crosses the acinar epithelium through these channels during primary saliva formation.

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Expression of aquaporin 1 (AQP1) water channels in human labial salivary glands

Cited by 9 publications

References 0 publications

Selective Down-Regulation of Aquaporin-1 in Salivary Glands in Primary Sjögren's Syndrome

Selective Down-Regulation of Aquaporin-1 in Salivary Glands in Primary Sjögren's Syndrome

Functional and molecular characterization of the fluid secretion mechanism in human parotid acinar cells

Evidence that aquaporin-8 is located in the basolateral membrane of rat submandibular gland acinar cells

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