• The Korean Journal of Physiology and Pharmacology
• /
• v.1 no.5
• /
• pp.495-504
• /
• 1997

Water transport is mediated by two distinct pathways, diffusional and channel-mediated water transport. The first molecular water channel was identified from human erythrocytes in 1992. Genetically-related proteins from other mammalian tissues have subsequently been identified to transport water, and the group is referred to as th "Aquaporins". Aquaporin-4 (AQP4) is most abundant in the brain, which may be involved in CSF reabsorption and osmoregulation. However, ontogeny and regulatory mechanisms of AQP4 channels have not been reported. Northern blot analysis showed that AQP4 mRNA began to be expressed in the brain just before birth and that its expression gradually increased by PN7 and then decreased at adult level. AQP4 was expressed predominantly in the ependymal cells of ventricles in newborn rats. And then its expression decreased in ependymal cells and increased gradually in other regions including supraoptic and paraventricular nuclei. AQP4 is also expressed in the subfornical organ, in which the expression level is not changed after birth. Cryogenic brain injury did not affect expression of AQP4 mRNA, while ischemic brain injury decreased it. Osmotic water permeability of AQP4 channel expressed in Xenopus oocytes was inhibited by the pretreatment of BAPTA/AM and calmidazolium, a $Ca^{2+}/Calmodulin$ kinase inhibitor, in a dose-dependent manner. These results indicate that the expression and the function of AQP4 channel are regulated by developmental processes and various pathophysiological conditions. These results will contribute to the understanding of fluid balance in the central nervous system and the osmoregulatory mechanisms of the body.

• Clinical and Experimental Reproductive Medicine
• /
• v.31 no.2
• /
• pp.119-131
• /
• 2004

연구 목적: 난소에서 분비되는 스테로이드 호르몬인 에스트로젠과 프로게스테론은 포유동물의 생식기관 발달과 정상적인 생식 기능, 수정과 배아의 착상에 중요한 역할을 한다. 특히 에스트로젠은 자궁내액을 내강으로 분비하여 자궁부종 기작에 중요한 역할을 한다. 자궁내액은 정자의 수정능력 획득과 착상전 배아의 발달에 매우 중요하다. Aquaporin (AQP)은 막관통 물수송 단백질로서 여러 조직에 넓게 분포되어 있으며, 세포간 또는 상피세포간 물의 이동에 중요한 역할을 한다. 본 연구에서는 생쥐 자궁에서 스테로이드 호르몬에 의해 조절되는 자궁내액의 이동에 AQP 유전자가 관여하는지를 알아보았다. 연구 재료 및 방법: 난소 절제술을 시행한 생쥐에 스테로이드 호르몬을 피하주사하고 6, 12, 24시간 간격으로 자궁조직을 적출하였다. 대조군은 sesame oil만을 주사한 후 6시간째에 수획한 자궁조직을 사용하였으며, 실험군은 시간대별과 스테로이드 처리별로 채취한 자궁조직에서 역전사중합효소반응을 수행하였다. 역전사중합효소반응을 통해 막관통 단백질인 AQP-4, -5, -8 mRNA의 발현양상을 살펴보았다. 또한 mRNA의 위치를 살펴보기 위해 laser microdissection을 이용하여 RT-PCR을 수행하였다. 마지막으로 자궁조직내에서의 단백질 발현 부위를 관찰하기 위해 면역조직화학염색을 실시하였다. 결 과: AQP-4, -5, -8 mRNA은 프로게스테론을 처리한 군보다 에스트로젠을 처리한 군에서 많이 발현되었으며, 에스트로젠을 주사한 지 6시간째 발현정도를 대조군과 비교할 때 AQP-4, -5, -8 mRNA가 각각 7.9배, 2.8배, 3.8배로 나타났다. AQP-4, -5, -8 mRNA는 간충조직보다 자궁내 상피조직에서 스테로이드 호르몬의 영향을 받아 발현양상의 차이가 나타났으며, 주로 에스트로젠의 영향을 받아 발현이 증가하였다. AQP-4 단백질은 에스트로젠을 24시간 처리한 후 프로게스테론을 처리한 군의 자궁내 상피조직에서 많이 발현되었으며, AQP-5와 -8 단백질은 에스트로젠을 처리한 군의 자궁내 상피조직에서 발현이 증가하였다. 결 론: 이상의 결과를 통해 AQP-4, -5, -8은 주로 에스트로젠에 의해 자궁내 상피세포에서 발현이 증가되는 것으로 보아 에스트로젠의 영향하에 일어나는 자궁내액의 이동으로 인한 자궁부종기작에 이동통로로서 관여하는 것으로 사료된다.

• Reproductive and Developmental Biology
• /
• v.33 no.1
• /
• pp.55-61
• /
• 2009

The epididymis in the male reproductive tract is the site where spermatozoa produced from the testis become mature. The epididymis is divided into 4 different segments, initial segment and caput, corpus, and caudal epididymis, depending upon functional and morphological features. Aquaporins (Aqps) are water channel molecules, which are present in the epididymis and play a major role in removal of epididymal water, resulting in creation of microenvironment for sperm maturation and concentration of sperms. Nandrolone decanoate (ND) is a synthetic anabolic-androgenic steroid, which is used to treat clinical diseases and improve physical ability and appearance. Even though it is well determined that the ND causes the male infertility by affecting the testis, little is known the effect of the ND on the epididymis. The present study was focused to examine the effect of ND at different treatment doses and periods on expression of Aqp1 and Aqp9 genes in the epididymis of pubertal rats. Results showed that mRNA expression of Aqp1 and Aqp9 genes among the parts of the epididymis was differentially regulated by ND treatment doses. In addition, treatment periods of ND caused differential expression of Aqp1 and Aqp9 mRNAs among segments of the epididymis. Therefore, it is believed that male infertility induced by ND could be resulted not only from malfunction of the testis but also from aberrant gene expression of Aqp1 and Aqp9 in the epididymis.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.15
• /
• pp.6391-6395
• /
• 2014

Overexpression of aquaporins (AQPs) has been reported in several human cancers. Epidermal growth factor receptor (EGFR)-extracellular signal-regulated kinases 1/2 (Erk1/2) are associated with tumorigenesis and cancer progression and may upregulate AQP expression. In this study, we demonstrated that EGF (epidermal growth factor) induces SiHa cells migration and AQP8 expression. Wound healing results showed that cell migration was increased by 2.79-1.50-fold at 24h and 48h after EGF treatment. AQP8 expression was significantly increased (3.33-fold) at 48h after EGF treatment in SiHa cells. An EGFR kinase inhibitor, PD153035, blocked EGF-induced AQP8 expression and cell migration and AQP8 expression was decreased from 1.59-fold (EGF-treated) to 0.43-fold (PD153035-treated) in SiHa. Furthermore, the MEK (MAPK (mitogen-activated protein kinase)/Erk (extracellular signal regulated kinase)/Erk inhibitor U0126 also inhibited EGF-induced AQP8 expression and cell migration. AQP8 expression was decreased from 1.21-fold (EGF-treated) to 0.43-fold (U0126-treated). Immunofluorescence microscopy further confirmed the results. Collectively, our findings show that EGF induces AQP8 expression and cell migration in human cervical cancer SiHa cells via the EGFR/Erk1/2 signal transduction pathway.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.32 no.1
• /
• pp.1-7
• /
• 2006

The present study was aimed to explore the role of sympathetic and parasympathetic nerves in the regulation of sodium transporters and water channels in the salivary gland. Rats were denervated of their sympathetic and parasympathetic nerves to the submandibular gland, and the glandular expression of sodium transporters and water channels was determined by Western blot analysis. The expression of either ${\alpha}1$ or ${\beta}1$ subunit of Na, K-ATPase was not significantly affected either by the sympathetic or by the parasympathetic denervation. The expression of subunits of epithelial sodium channels was significantly increased both in the denervated and contralateral glands either by the sympathetic or by the parasympathetic denervation. Neither the sympathetic nor the parasympathetic denervation significantly altered the expression of aquaporin-1 (AQP1). Nor was the expression of AQP4 affected significantly by the parasympathetic or the sympathetic denervation. On the contrary, the expression of AQP5 was significantly increased not only by the parasympathetic but also by the sympathetic denervation. These results suggest that sympathetic and parasympathetic nerves have tonic regulatory effects on the regulation of certain sodium transporters and AQP water channels in the salivary gland.

• Development and Reproduction
• /
• v.19 no.1
• /
• pp.53-60
• /
• 2015

Environmental conditions during early mammalian embryo development are critical and some adaptational phenomena are observed. However, the mechanisms underlying them remain largely masked. Previously, we reported that AQP5 expression is modified by the environmental condition without losing the developmental potency. In this study, AQP11 was examined instead. To compare expression pattern between in vivo and in vitro, we conducted quantitative RT-PCR and analyzed localization of the AQP11 by whole mount immunofluorescence. When the fertilized embryos were developed in the maternal tracts, the level of Aqp11 transcripts was decreased dramatically until 2-cell stage. Its level increased after 2-cell stage and peaked at 4-cell stage, but decreased again dramatically until morula stage. Its transcript level increased again at blastocyst stage. In contrast, the levels of Aqp11 transcript in embryos cultured in vitro were as follows. The patterns of expression were similar but the overall levels were low compared with those of embryos grown in the maternal tracts. AQP11 proteins were localized in submembrane cytoplasm of embryos collected from maternal reproductive tracts. The immune-reactive signals were detected in both trophectoderm and inner cell mass. However, its localization was altered in in vitro culture condition. It was localized mainly in the plasma membrane of the blastocysts contacting with external environment. The present study suggests that early stage embryo can develop successfully by themselves adapting to their environmental condition through modulation of the expression level and localization of specific genes like AQP11.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.4
• /
• pp.1375-1383
• /
• 2015

Background: Objective Myocardin-related transcription factor (MRTF)-A is a Rho signaling-responsive co-activator of serum response factor (SRF). The purpose of this study is to investigate the role of MRTF-A and AQP1 (aquaporin 1) in pathological vascular remodeling. Materials and Methods: MRTF-A, AQP1 and neointima expression was detected both in the wire injured femoral arteries of wild-type mice and the atherosclerotic aortic tissues of $ApoE^{-/-}$ mice. Expression of ICAM-1, matrix metallopeptidase 9 (MMP-9) and integrin ${\beta}1$ were also assayed. The intercourse relationship between the molecules were investigated by interfering RNA and inhibitor assay. Results: MRTF-A and AQP1 expression were significantly higher in the wire injured femoral arteries of wild-type mice and in the atherosclerotic aortic tissues of $ApoE^{-/-}$ mice than in healthy control tissues. Both in wire-injured femoral arteries in MRTF-A knockout ($Mkl1^{-/-}$) mice and atherosclerotic lesions in $Mkl1^{-/-}$; $ApoE^{-/-}$ mice, neointima formation were significantly attenuated and the expression of AQP1 were significantly decreased. Expression of ICAM-1, matrix metallopeptidase 9 (MMP-9) and integrin ${\beta}1$, three SRF targets and key regulators of cell migration, and AQP1 in injured arteries was significantly weaker in $Mkl1^{-/-}$ mice than in wild-type mice. In cultured vascular smooth muscle cells (VSMCs), knocking down MRTF-A reduced expression of these genes and significantly impaired cell migration. Underlying the increased MRTF-A expression in dedifferentiated VSMCs were the down-regulation of microRNA-300. Moreover, the MRTF-A inhibitor CCG1423 significantly reduced neointima formation following wire injury in mice. Conclusions: MRTF-A could be a novel therapeutic target for the treatment of vascular diseases.

• Development and Reproduction
• /
• v.26 no.2
• /
• pp.59-69
• /
• 2022

Many efforts have been made to study the expression of aquaporins (AQP) in the mammalian reproductive system, but there are not enough data available regarding their localized expression to fully understand their specific roles in male reproduction. The present study investigated the expression and localization patterns of different AQP subtypes in the adult mouse testes and testicular spermatozoa using an immunofluorescence assay. All the studied AQPs were expressed in the testes and revealed subtype-specific patterns in the intensity and localization depending on the cell types of the testes. AQP7 was the most abundant and intensive AQP subtype in the seminiferous tubules, expressing in Leydig cells and Sertoli cells as well as all stages of germ cells, especially the spermatids and testicular spermatozoa. The expression pattern of AQP3 was similar to that of AQP7, but with higher expression in the basal and lower adluminal compartments rather than the upper adluminalcompartment. AQP8 expression was limited to the spermatogonia and Leydig cells whereas AQP9 expression was exclusive to tails of the testicular spermatozoa and elongated spermatids. Taken together, the abundance and distribution of the AQPs across the different cell types in the testes indicating to their relavance in spermatogenesis, as well as in sperm maturation, transition, and function.

• Proceedings of the Korean Society of Embryo Transfer Conference
• /
• 2003.10a
• /
• pp.62-62
• /
• 2003

• The Korean Journal of Physiology and Pharmacology
• /
• v.10 no.4
• /
• pp.213-216
• /
• 2006

The present study was aimed to determine whether nitric oxide (NO) plays a role in the regulation of aquaporin (AQP) channels in the kidney. Male Brattleboro rats ($250{\sim}300\;g$ body weight) were used. The experimental group was treated with $N^G$-nitro-L-arginine methyl ester (L-NAME, 100 mg/L drinking water) for 1 week, and cotreated with indomethacin (5 mg/kg, twice a day, i.p.) for the last two days. Control groups were treated with either L-NAME for 1 week, indomethacin for 2 days, or without any drug treatment. The abundance of AQP1, AQP2 and AQP3 proteins in the kidney was determined by Western blot analysis. Indomethacin downregulated AQP channels, whereas L-NAME by itself showed no significant effects on them. The indomethacin-induced downregulation of AQP2 and AQP3 was significantly blunted in L-NAME-treated rats, while that of AQP1 was not affected. These results suggest that endogenous NO, when stimulated, may downregulate AQP channels that are specifically regulated by AVP/cAMP pathway in the kidney.