Differential Expressions of Aquaporin Subtypes in Female Reproductive Tract of Mice

Abstract

Although many aquaporin (AQP) transcripts have been demonstrated to express in the female reproductive tract, the defined localizations and functions of AQP subtype proteins remain unclear. In this study, we investigated the expression of AQP1, AQP3, AQP5, AQP6, and AQP9 proteins in female reproductive tract of mouse and characterized their precise localizations at the cellular and subcellular levels. Immunofluorescence analyses for AQP1, AQP3, AQP6, and AQP9 showed that these proteins were abundantly expressed in female reproductive tract and that intense immunoreactivities were observed in mucosa epithelial cells with a subtype-specific pattern. The most abundant aquaporin in both vagina and uterine cervix was AQP3. Each of AQP1, AQP3, AQP6, and AQP9 exhibited its distinct distribution in stratified squamous or columnar epithelial cells. AQP9 expression was predominant in oviduct and ovary. AQP1, AQP3, AQP6, and AQP9 proteins were mostly seen in apical membrane of ciliated epithelial cells of the oviduct as well as in both granulosa and theca cells of ovarian follicles. Most of AQP subtypes were also expressed in surface epithelial cells and glandular cells of endometrium in the uterus, but their expression levels were relatively lower than those observed in the vagina, uterine cervix, oviduct and ovary. This is the first study to investigate the expression and localization of 5 AQP subtype proteins simultaneously in female reproductive tract of mouse. Our results suggest that AQP subtypes work together to transport water and glycerol efficiently across the mucosa epithelia for lubrication, proliferation, energy metabolism and pH regulation in female reproductive tract.

Oxygen levels affect oviduct epithelium functions in air–liquid interface culture

“…This suggests the involvement of other factors in the regulation of water transport through the epithelium, such as the water channel aquaporins (e.g. AQP1 , AQP3 , AQP6 and AQP9 in the oviduct) and cystic fibrosis transmembrane conductance regulator ( CFTR ) (Im et al 2020 ). Further investigations are warranted to assess the activities of ion and water channels at the protein level to validate the mechanisms governing the OFS volume.…”

Role of aquaporin 3 in reproductive performance of dairy goats after repeated estrus synchronization stimulation

“…Caspase‐3 and caspase‐9 primarily act as apoptosis performers and are markers of ovarian granulocyte apoptosis (Araya et al, 2021). AQP3 affects cell proliferation and apoptosis by regulating osmotic pressure inside and outside the cell membrane (Im et al, 2020). Therefore, we consider that AQP3 overexpression increased the apoptosis rate of ovarian granulosa cells at 24 h following AQP3 transfection.…”

“…RNA sequencing revealed that KIF26B , AQP3 , SPIB and Novel00378 were the common DEGs in the ovarian tissues of dairy goats treated with repeated FSH‐ or eCG‐mediated ES treatment. Among the common genes, AQP3 functions as a hydrophilic membrane protein in mammalian ovarian cells (Im et al, 2020). By participating in the regulation of sperm volume, AQP3 can prevent cell swelling caused by low osmotic pressure when sperms enter the vagina (Qi & En‐Kui, 2011), optimizing the ability of sperms to bind to oocytes (Chen et al, 2010).…”

“…Similarly, repeated eCG-mediated ES treatment results in 114 DEGs, including AQP3, KIF26B, SPIB and Novelgene 00378, in dairy goat ovarian tissues (Sun, Liu, Luo, Chen, Li, et al, 2019). Among these genes, the SPIB gene plays a sequence-specific transcriptional activation role in plasma cells and promotes the development of dendritic cells (Freiburghaus et al, 2018); KIF26B is essential for the development of embryonic kidneys and plays a role in the attachment of mesenchymal cells (Teng et al, 2018); the function of Novelgene 00378 is unknown now; AQP3 is essential for follicular homeostasis (maintaining the material exchange between the follicle and external environment) and fat-related transport of ovarian granulosa cells and oocytes (Im et al, 2020). Furthermore, AQP3 function enables nutrient transportation by ovarian granulosa cells via the cell water channel (Jun Woo et al, 2011).…”

Impacts of vitrification on the transcriptome of human ovarian tissue in patients with gynecological cancer

“…In this study, most genes related to ovarian reserve and primordial follicle reactivation were not altered; however, a larger number of dysregulated genes were identified. Some studies have reported that AQP1, AQP3, and AQP9 present in the ovarian follicle corpus luteum contribute to the rapid growth of follicles during folliculogenesis, follicular fluid accumulation, and nutrient supply to granulosa cells and oocytes (Lm et al, 2020). Sales et al (2016) found that mRNA levels of AQP3 and AQP9 in bovine ovaries were downregulated, following vitrification, which can cause AQP3 upregulation and AQP1 mRNA downregulation in human ovary tissues, suggesting that AQP1 and AQP3 may have different functional mechanisms for human follicle growth.…”