Expression and Localization of Aqua-glyceroporins AQP3 and AQP9 in Rat Oral Epithelia

Abstract

Aquaporins (AQPs) are a family of small integral membrane proteins made up of 6 hydrophobic, a-helical, membrane-spanning domains surrounding a highly selective aqueous pore. AQP3, AQP7, and AQP9, termed aqua-glyceroporins, are known to be involved in the transport of water, glycerol, and other small molecules. In this study, we investigated the expression and localization of aqua-glyceroporins in rat oral stratified squamous epithelia of the palate, the buccal mucosa, the inferior aspect of the tongue, and the oral floor by using RT-PCR, immunofluorescence, and immunogold electron microscopy. AQP3 and AQP9 mRNAs were expressed in whole oral epithelium. Immunostaining for AQP3 was recognized in each type of epithelium. The results suggest that AQP3 synthesis begins predominantly in the cytoplasm of the basal cells. During the process of epithelial cell differentiation, AQP3 protein appears to accumulate and be transported to the plasma membrane, from where it is incorporated into the cornified or surface layers. The intracellular localization of AQP3 appears to correlate with the differentiation of keratinocytes, suggesting that it acts as an enhancer of the physiological permeability barrier together with membrane coating granules. The distribution pattern of AQP9 was limited to the marginal areas of the basal and suprabasal layers, which was different from that of AQP3. This difference in distribution between AQP3 and AQP9

Optimization of an oral mucosa in vitro model based on cell line TR146

“…Moreover, a correlation was suggested between AQP3 localization and the differentiation of keratinocytes. 71 To understand the expression of aquaporins in our human buccal mucosa model, further investigations on their functionality in the oral mucosa are necessary.…”

Regulation of Aquaporin 3 Expression by the AhR Pathway Is Critical to Cell Migration

“…AQP3 is expressed in epithelia (oral, mammary gland) (Poveda et al, 2014;Mobasheri and Barrett-Jolley, 2014). Its expression has been shown to be regulated not only by a number of physiological stimuli including Epidermal Growth Factor (EGF) or Hepatocyte Growth Factor (HGF) but also by cellular regulatory processes such as miRNA production (miR-874) (Jiang et al, 2014;Zhi et al, 2014).…”