Disease relevance of AQP3

• Zinc and cadmium, other common causes of pneumoconiosis, had no effect on the water permeability of AQP3 [1].
• AQP3 staining was found in basal epithelial cells of the normal, Fuchs' dystrophy, and keratoconus corneas but throughout the entire epithelium of PBK/ABK corneas [2].
• AQP3 expression was unaffected by dialysis duration or peritonitis history [3].
• AQP1 and AQP3, psoriasin, and nitric oxide synthases 1-3 are inflammatory mediators in erythema toxicum neonatorum [4].
• By contrast, in acute and chronic atopic eczema strong AQP3 staining was found in both the stratum basale and the stratum spinosum [5].

Psychiatry related information on AQP3

• In response to water deprivation, AQP2 and AQP3 expression increased significantly in the cortex and medulla of 2-month-old rats but remained unchanged in the medulla or slightly increase in the cortex of 7-month-old animals [6].

High impact information on AQP3

• We report that two members of the aquaporin family, AQP3 and AQP7, are expressed in immature DCs and are downregulated after maturation [7].
• Aquaporin-2 is a vasopressin-regulated water channel located in the apical membrane, and aquaporin-3 is a constitutive water channel located in the basolateral membrane [8].
• Little AQP7 or AQP9 mRNA was detected by reverse transcription-PCR in either cell line, whereas AQP3 mRNA expression was 2-fold lower in R15 cells than in CL3 cells [9].
• When AQP3 expression in CL3 cells was knocked down by RNA interference, CL3 cells accumulated less arsenic and became more resistant to As(III) [9].
• Here we report that both water and glycerol permeability of human AQP3 is inhibited by copper [10].

Chemical compound and disease context of AQP3

• Our findings also suggest that AQP3 expression in vivo is regulated by mechanisms other than glucose exposure, peritonitis and traditional growth factors [3].
• Dexamethasone-regulated AQP3 expression might be important in certain forms of pulmonary diseases accompanied by airway hypersecretion that are treated by corticosteroid administration [11].

Biological context of AQP3

• The gene expression of AQP3 and its protein biosynthesis in HPMC were inducible following exposure to glucose in a dose- and time-dependent manner (P < 0.0001) [12].
• Thus we confirmed that the OAs are composed of AQP4 in skeletal muscles, and further demonstrated that some of the IMP clusters are composed of AQP3 and may participate in maintaining osmotic homeostasis in skeletal myofibers [13].
• AQP-3 protein also exhibits a similar alteration likely due to a similar increase in its glycosylation state [14].
• The gel electrophoresis of the reverse transcription polymerase chain reaction (RT-PCR) product of total RNA samples extracted from normal human muscle specimens by using the oligonucleotide primers for AQP3 contained a band of 629 base pairs which corresponded to the base pair length between two primers of AQP3 [15].
• The nucleotide sequence of this RT-PCR product coincided with that of AQP3 [15].

Anatomical context of AQP3

• Although both aquaporins permit water flow across the cell membrane, only AQP3 was permeable to glycerol and urea (Pgly > Pur) [16].
• By immunofluorescence, anti-AQP3 antibodies stained the plasma membranes of both normal and Colton-null erythrocytes [17].
• The uptake of glycerol into oocytes expressing AQP3 was linear up to 165 mM [16].
• Although transcripts encoding for AQP3 has been detected by reverse transcription-polymerase chain reaction (RT-PCR) in murine peritoneal mesothelium, to date there is no documentation of protein expression on peritoneal mesothelial cells [12].
• AQP3 resides in the basolateral membranes of collecting duct principal cells providing an exit pathway for water, and AQP4 is abundant in brain, where it apparently functions as the hypothalamic osmoreceptor responsible for secretion of antidiuretic hormone [18].

Associations of AQP3 with chemical compounds

• HgCl2 reversibly reduced the Lp of AQP3 and increased sigmaglyc to 1 and sigmaform to 0 [19].
• In addition, phloretin (0.1 mM) inhibited Pf of AQP3 by 35%, whereas it did not alter Pgly or Pur [16].
• The sulfhydryl reagent p-chloromercuriphenylsulfonate (1 mM) abolished Pf of AQP3, whereas it did not affect Pgly [16].
• METHOD: Our present study was designed to explore the gene and protein expression of AQP3 in HPMC and its regulation under different concentrations of glucose [12].
• Incubation of keratinocytes in sorbitol-added hypertonic medium increased AQP3 mRNA expression [20].

Regulatory relationships of AQP3

• Short-term control of water permeability occurs via vesicular trafficking of AQP2 and long-term control through changes in the abundance of AQP2 and AQP3 water channels [21].
• AQP3 knockdown by small interfering RNA inhibited EGF-induced AQP3 expression and cell migration [22].
• The cystic fibrosis transmembrane conductance regulator activates aquaporin 3 in airway epithelial cells [23].
• The PK-A inhibitors (H-89, H-9) inhibited the expression of AQP3 mRNA enhanced by VIP and cAMP [24].

Other interactions of AQP3

• Aquaporins are a family of intrinsic membrane proteins that function as water-selective channels (except aquaporin-3 and aquaporin-7, which are permeable to urea and glycerol as well) in the plasma membranes of many cells [25].
• We conclude that AQP3 and AQP5 together may provide a pathway for transcellular osmotic water flow in the formation of the primary saliva [26].
• The distribution of the AQP1 and AQP3 proteins was also studied by immunohistochemical staining using affinity-purified polyclonal antibodies [27].
• When treated with CT, water permeability of AQP4 was facilitated while that of AQP3 was suppressed [28].
• AQP1 is expressed in apical and basolateral membranes of proximal tubules and descending limbs of Henle, AQP2 predominantly in apical membranes of principal and inner medullary collecting duct cells and AQP3 in basolateral membranes of kidney collecting duct cells [29].

Analytical, diagnostic and therapeutic context of AQP3

• Further study is warranted to elucidate the role of AQP3 in HPMC for maintaining the ultrafiltration of the peritoneal membrane [12].
• Reverse transcriptase-polymerase chain reaction, Western analysis, and immunohistochemistry were used to determine expression and localization of AQP1 and AQP3 [30].
• To identify the mercury-sensitive site, six individual cysteine residues in human AQP3 (at positions 11, 29, 40, 91, 174, and 267) were altered by site-directed mutagenesis [31].
• We observed that AQP3 is selectively expressed on the surface of basal cells, allowing the separation by flow cytometry of AQP3+ basal cells and AQP3- ciliated and secretory cells [32].
• Immunogold labelling electron microscopy revealed that the gold particles indicating the presence of AQP3 molecules were located mainly at the inside surface of muscle plasma membrane [15].

References