Cellular and subcellular localization of aquaporins 1, 3, 8, and 9 in amniotic membranes during pregnancy in mice

Abstract

The amniotic membrane encloses the amniotic fluid and plays roles in the regulation of amniotic fluid flux through the intramembranous pathway during pregnancy. Aquaporins (AQPs) 1, 3, 8, and 9 are expressed in amniotic membranes. AQPs are water channel proteins that facilitate the rapid flux of water or small molecules across the plasma membrane. Recently, additional roles of AQPs in facilitating cell migration, proliferation, and apoptosis have been suggested, with AQPs being distributed in the appropriate subcellular regions for their functions. The cellular and subcellular distributions of AQPs in the amniotic membrane however remain unclear. We have examined the cellular and subcellular localization of AQPs in amniotic membranes during pregnancy in mice. After embryonic day 12 (E12), AQP1 was distributed in the plasma membrane of finely branched cell processes in the amniotic fibroblasts. AQP3 was present in both epithelial cells and fibroblasts between E10 and E12. The distribution of AQP3 in the epithelial cells dynamically changed as follows: at E14 in the lateral membrane and apical junction; at E16 in the lateral membrane alone; at E17 in the lateral membrane and cytoplasm. AQP8 was expressed in the epithelial cells and complementarily localized in the apical junction and the lateral membrane. AQP9 was detected only in the apoptotic cells of the epithelium. These cellular and subcellular localizations of amniotic AQPs indicate that each AQP plays distinct functional roles, such as in water and urea transport, cell migration, cell proliferation, and apoptosis, for amniotic fluid homeostasis or tissue remodeling of amniotic membranes.

Loss of Aquaporin-3 in Placenta and Fetal Membranes Induces Growth Restriction in Mice

“…In addition, AQP1 localization at the apical membrane of epithelial cells of both amnion and visceral yolk sac endoderm was also first described. Inconsistently with the previous reports ( Damiano et al, 2001 ; Kobayashi & Yasui, 2010 ), AQP9 expression was not observed either in amnion or placenta except mesothelial cells of the perimetrium.…”

“…AQP3, AQP8 and AQP9 localize not only in epithelial cells of amnion but also in cytotrophoblasts and syncytiotrophoblasts of placenta in human ( Damiano et al, 2001 ), whereas AQP4 is reported to express in stroma of human placenta ( De Falco et al, 2007 ). In mice, AQP3 expression in amnion and trophoblasts of the labyrinth has been demonstrated ( Kobayashi & Yasui, 2010 ). Here we first described the expression of AQP3 in the basolateral membranes of visceral yolk sac endoderm.…”

Activation of TGF-β1 by AQP3-Mediated H2O2 Transport into Fibroblasts of a Bleomycin-Induced Mouse Model of Scleroderma

“…Although AQP3 is expressed in both human and mouse fibroblasts (Kobayashi and Yasui, 2010;Li et al, 2010), to our knowledge, no study has examined AQP3 expression in fibroblasts in scleroderma or its functions with respect to scleroderma pathogenesis. Herein, we showed that the levels of AQP3 in the dermis and H 2 O 2 in skin increased in BLMinduced mouse models of scleroderma with the duration of BLM injection, and AQP3 protein overexpression was observed in fibroblasts in skin samples obtained from the injection area of BLM mice.…”

The Effects of Female Sexual Hormones on the Expression of Aquaporin 5 in the Late-Pregnant Rat Uterus

“…Moreover, the cellular and subcellular localizations of amniotic AQPs indicate that the AQPs play distinct functional roles, such as apoptosis for amniotic fluid homeostasis or the tissue remodeling of amniotic membranes during pregnancy. It was proven that AQP1, 3, 8, 9, and 11 play crucial roles in the transfer of water across the placenta [21]. …”