水-甘油通道蛋白7基因(AQP7)的研究进展

水-甘油通道蛋白7是水通道蛋白家族中的一员,它既可以转运水,也可以转运甘油等小分子物质。本文从水-甘油通道蛋白的组成成员、结构与分布、功能与调控以及与疾病的关系等方面综述了水-甘油通道蛋白的最新研究进展,并对今后的研究方向进行了展望。     

水通道蛋白在小鼠小肠中的表达和定位

探明水通道蛋白在小鼠小肠中的表达及定位,为研究小肠水转运过程中的细胞和分子机制奠定理论基础。本文运用RT-PCR和免疫印迹技术检测小鼠十二指肠、空肠和回肠中水通道蛋白的表达情况,结果显示,AQP3在小鼠空肠中存在基因和蛋白表达,AQP4在小鼠回肠中存在基因和蛋白表达。为进一步明确这两种水通道蛋白在小肠中的表达位置,通过免疫组织化学的方法进一步证实AQP3主要表达在小鼠空肠黏膜上皮细胞,而AQP4主要表达在小鼠回肠隐窝细胞基底膜。     

水-甘油通道蛋白基因与体脂代谢相关性研究进展

水-甘油通道蛋白在机体内各器官组织广泛表达,对维持机体多个器官系统的正常生理功能,甘油运输的调节,体内脂肪物质代谢具有重要的生理意义。本文对水-甘油通道蛋白基因的结构特点、在甘油运输和脂肪代谢中的重要作用以及基因遗传多态性与体脂性状相关性的研究进展进行综述。     

水通道蛋白在动物疾病发生过程中的作用研究进展

水通道蛋白(AQP)是细胞上存在的一种膜孔道蛋白。动物、植物、微生物细胞上均有水通道蛋白的表达,其主要功能是参与机体的水与电解质代谢。近年来,针对水通道蛋白在机体所发挥的功能方面研究较多,发现水通道蛋白不仅参与机体生理方面的调控,而且在一些疾病的发生发展过程中也发挥重要的作用。综述概括了水通道蛋白在脑、肺、肾脏、肠道等组织器官的定位;重点阐述了水通道蛋白在动物脑部疾病、肺部疾病、肾脏疾病、肠道疾病发展过程中所发生的变化。旨在为患病动物出现水与电解质代谢紊乱症状时,对水通道蛋白发生的变化研究提供参考。     

水通道蛋白9的研究进展

水通道蛋白9在机体内许多器官组织中表达,它对水、尿素、甘油等分子均有通透性,其基因结构、染色体定位、蛋白质结构、组织分布和生理功能也已得到了较为深入的研究。本文对水通道蛋白9基因的结构特点、分子结构、分布和生理功能作一综述,以期为相关疾病诊治和生产实践提供理论依据。     

水通道蛋白8原核表达载体的构建及其表达纯化

为研究水通道蛋白8 (aquaporin 8,AQP8)的结构和功能,构建AQP8原核表达载体,表达纯化GST-AQP8融合蛋白。PCR扩增小鼠AQP8羧基端270bp的特异序列,定向连接到pGEX-4T-1载体,构建原核表达载体pGEX-4T-1/AQP8,转化大肠杆菌表达菌株BL21,IPTG诱导表达GST-AQP8融合蛋白,并对融合蛋白进行亲和层析纯化。酶切鉴定和DNA测序结果表明p GEX-4T-1/AQP8表达载体构建成功; SDS-PAGE结果证实GST-AQP8融合蛋白有效表达且成功纯化。本研究成功制备高纯度的GST-AQP8融合蛋白,为进一步探究AQP8的结构和功能提供基础。     

肠道中水通道蛋白的表达和功能研究进展

肠道是机体重要的水盐代谢器官,其对于液体的转运能力仅次于肾脏,在维持机体水盐平衡中发挥着重要作用。水通道蛋白(aquaporin,AQP)是广泛存在于原核和真核细胞膜上快速转运水分子的特异性孔道蛋白,在机体许多器官的体液转运过程中发挥重要作用。因此,水通道蛋白在肠道表达及液体转运中的作用一直是研究热点。文章对肠道水转运机制、水通道蛋白在肠道中的表达及其作用进行综述。     

水牛水通道蛋白9基因克隆及其表达分析

本研究旨在对水牛水通道蛋白9 (aquaporins 9,AQP9) 基因进行克隆,并对其在水牛不同组织中的表达规律及其在水牛卵巢和睾丸组织中的表达差异进行探索。根据GenBank上黄牛AQP9基因序列(登录号:NM_001205833.1)设计特异性引物,以水牛睾丸组织cDNA为模板,应用RT-PCR方法扩增AQP9基因编码区片段;运用生物信息学方法分析其核苷酸序列的保守性和氨基酸的理化性质;应用实时荧光定量PCR技术分析AQP9基因在水牛组织中的表达情况;免疫组织化学方法分析AQP9蛋白在不同发育阶段水牛卵泡及睾丸组织中的表达差异。结果表明,克隆获得了888 bp的水牛AQP9基因编码区序列,其编码295个氨基酸。多重序列比较显示,水牛AQP9核苷酸序列与牛、猪、绵羊和人相应序列相似性分别为99%、90%、97%、88%;氨基酸序列的同源性分别为99%、86%、97%、83%,系统进化树分析结果推测,AQP9基因在物种进化过程中具有高度保守性。实时荧光定量PCR结果显示,AQP9基因在水牛肝脏、肺脏、大脑、皮肤、睾丸和卵巢组织中有不同程度的表达,在肝脏组织中表达最高,皮肤和睾丸次之,肺脏和卵巢表达较低。免疫组化结果显示,在卵巢组织中,AQP9蛋白表达随卵泡发育时期的不同而变化,并随着卵泡发育其表达逐渐增强;在睾丸组织中,AQP9蛋白在各级精母细胞和间质细胞中均有表达。结果提示,成功克隆得到水牛AQP9基因序列;AQP9在水牛卵巢和睾丸中的表达及其功能可能与水牛卵泡发育和精子发生有重要的关联。     

鸡水通道蛋白研究进展

<正>水通道蛋白(Aquaporin,AQP)是细胞膜上能高效选择性地转运水分子的特异性孔道~([1])。迄今为止已经发现了13个不同类型的水通道蛋白(AQP0-AQP12),在结构上,AQPs是整合膜水转运蛋白小分子混合物(～30 kDa)。组织定位和调节研究表明,AQPs在生理上涉及液体分泌和吸收的细胞中表达,例如在眼睛,中枢神经系统,外分泌腺,肾脏和脂肪组织中~([2])。AQPs根据功能可分为三类~([3]):(a)只转     

氯气中毒对小鼠主要脏器水通道蛋白4表达的影响

以昆明小鼠为研究对象,探讨氯气中毒对小鼠主要脏器(心、肝、脾、肺、肾和脑)水通道蛋白4表达的影响.将40只30日龄昆明小鼠随机分为试验组和对照组,用氯气诱发中毒性肺水肿模型,剖检观察各脏器病理变化.并运用免疫组化法(SABC)检测各脏器中水通道蛋白4的表达.结果显示试验组出现肺水肿的临床症状,除肝脏外其他脏器水通道蛋白4的表达明显高于对照组(P<0.01),HE染色见水肿典型病变.结论得出氯气中毒致使小鼠主要脏器的水通道蛋白4的表达上升,这可能与水通道蛋白4的转运水的功能直接有关.     

Immunolocalization of aquaporins in rat brain

The aquaporins (AQPs) are a family of homologous water channels expressed in many tissues. In this study, the expression and immunolocalization of different AQP subtypes in rat brains were investigated by RT-PCR, immunohistochemistry and immunofluorescence. The data showed that AQP1 was expressed in the subpial processes of astrocytes, choroid plexus and ependyma. AQP3, AQP5 and AQP8 had similar distribution patterns in piriform cortex, choroid plexus, hippocampus and dorsal thalamus. AQP4 and AQP9 were widely expressed in the rat brain and distributed in the subpial processes of astrocytes, ependyma, dorsal thalamus, hippocampus, white matter, suprachiasmatic nucleus (SCN) and supraoptic nucleus. AQP3, AQP4, AQP5, AQP8 and AQP9 were found in the Bergmann glial cells of cerebellum, cochlear nucleus and trapezoid nuclei. The distinct localization of various AQPs in cerebrum and the similarities of distribution patterns within cerebellum, cochlear nucleus and trapezoid nuclei suggest that AQPs may play an important role in maintaining the specific microenvironments of the brain.     

The role of aquaporin 4 in the brain

Emerging evidence suggests that aquaporin (AQP) 4 water channels play an important role in water homeostasis in the brain. These water channels are most abundant in the cell membrane of astrocytes, but are also present within ependymal cell membranes and in osmosensory areas of the hypothalamus. Water transport through AQP4 depends on concentration gradients across the membrane, but the rate of transport is determined by the capacity of astrocytes to up- and down-regulate AQP4 numbers, their location within the membrane, and the overall permeability of the channel. Other functions of brain AQP4 involve potassium uptake and release by astrocytes, migration of glial cells, glial scarring, and astrocyte-to-astrocyte cell communication. AQP water channels are involved in formation and control of edema in the brain and in multiple disease processes in the brain, such as seizures and tumors. There is abundant scientific literature on AQP4 describing its structure, function, location, and role in water homeostasis and edema in the brain. Investigation of AQP expression in the canine and feline brain should be pursued so that clinically relevant comparisons between findings in mice, rats, and people and animal patients can be made.     

Neurochemical properties of aquaporin 1-expressing sensory neurons from the ovine trigeminal ganglion

Aims of the present study were to investigate the distribution and morphology of aquaporin 1-immunoreactive (AQP1-IR) neurons in the sensory ganglia of the sheep. Double immunohistochemical staining was applied to figure out whether substance P (SP), calcitonin gene-related peptide (CGRP) and galanin are present in AQP1-bearing primary afferent neurons. The expression of AQP1 was present only in trigeminal ganglion, whereas in nodose ganglion, jugular ganglion as well as C(1) -C(7) dorsal root ganglia no presence of AQP1 was found. In trigeminal ganglion, 15.4 ± 2.3% of Hu C/D-IR neurons (pan-neuronal marker) showed the presence of AQP1. The vast majority of AQP1-IR trigeminal sensory neurons (approximately 69.6 ± 3.3%, n = 5) were classified as middle in size, 28.6 ± 3.0% of AQP1-IR neurons were small and only 1.8 ± 0.6% of AQP1-positive neurons were large in size. Amongst the population of AQP1-IR trigeminal neurons as many as 58.5 ± 3.9% were immunopositive to SP, 30.7 ± 2.3% showed the presence of CGRP and 10.9 ± 0.2% coexpressed galanin. In trigeminal ganglion, SP-IR as well as CGRP-IR (but not galanin-IR) nerve fibres were found in close neighbourhood of AQP1-IR neurons. It is concluded that AQP1 is present in certain neuronal subsets of the ovine trigeminal ganglion; however, the exact role of this water channel has to be elucidated.     

Identification and characterization of aquaporin-9 (AQP9) in porcine hepatic tissue and hepatocytes in monolayer culture

Aquaporins (AQPs) are members of a large family of integral membrane proteins involved in the rapid movement of water and neutral solutes across cell membranes. In this study, we have prepared an affinity-purified porcine-specific polyclonal antiserum to AQP9 and have investigated the distribution and expression of AQP9 in pig liver tissue and in hepatocytes in primary culture. Immunocytochemical analysis showed that AQP9 was primarily localized in the membrane structures of hepatocytes and was not associated with intrahepatic bile ducts or blood vessels. Western blot analysis indicated that AQP9 ranged in apparent molecular mass between 27 and 38 kD in whole liver and hepatocyte membrane fractions; minor components were also observed at approximately 34 kD in the cytosol compartment of hepatocytes, bile duct and gall bladder. A prominent immunoreactive band at 44 kD was shown to be an artifact of Western blot analysis. In primary cultures of porcine hepatocytes, glucagon enhanced absolute levels of AQP9 protein, while gene expression was enhanced by T3 and glucagon. Insulin alone had no discernable influence on AQP9 gene expression or its cellular protein levels. These data suggest that AQP9 is a major AQP in porcine hepatic tissue and appears to be primarily responsive to glucagon induction.     

Aquaporin 9 is expressed in the epididymis of immature and mature pigs

Aquaporins (AQPs) are channel proteins that facilitate the transepithelial and bidirectional movement of water. AQP9 is an aquaporin that is expressed in the mammalian epididymis. This water transport contributes to epididymal sperm concentration. This study aimed to examine the morphology of epididymal epithelium in piglets and boars, as well as the expression and immunolocalization of AQP9. The piglets presented an epididymal epithelium in differentiation with principal, basal and apical cells. The cellular population of the epididymal epithelium in boars consisted of principal, basal, apical, clear and narrow cells. The migratory cells known as halo cells were observed in the epididymis of both piglets and boars. AQP9 expression presented differences between piglets and boars. Moderate intensity of AQP9 immunoreaction was observed in the apical border of the epididymal epithelium of the caput and cauda regions in the piglet epididymis. A moderate‐to‐intense reaction for AQP9 was observed in the nuclei of epithelial cells of the three epididymal regions in the boar epididymis. The region of the cauda epididymis showed reactivity for AQP9 also in the apical border of the epithelium. It is believed that the AQP9 is already functional in piglets at only 1 week of age and is more active, playing a pivotal role in the caput and cauda regions of the epididymis. Moreover, the intense AQP9 expression in the apical border of epithelial cells in the cauda region of the boar epididymis suggests a higher performance of AQP9 in this region, where sperm complete their maturation process, stored and concentrated.     

Cloning of Buffalo AQP9 Gene and Analysing its Expression in the Buffalo Tissues

Cloning buffalo AQP9 gene and analyzing its expression in buffalo tissues.A pair of primers was designed according to the released bovine AQP9 sequences in GenBank,which was used to clone buffalo AQP9 gene.The AQP9 gene was amplified by RT-PCR,whose nucleotide sequence and protein structure were analyzed by bioinformatics methods.The expression of AQP9 in buffalo tissues was assayed by Real-time quantitative PCR.The expression of AQP9 gene in buffalo ovary and testis tissue was detected by immunohistochemical staining method.The results showed that the cloned ORF length of buffalo AQP9 gene was 888 bp,which coded 295 amino acids.The results of multiple sequence comparison showed that the nucleotide sequence of buffalo AQP9 shared 99%,90%,97% and 88% homologeous compared with that of Bos taurus,Sus scrofa,Ovis ariessis and Homo sapiens,respectively,while shared 99%,86%,97%,83% homologeous for amino acids,respectively.Phylogenetic tree analysis indicated that AQP9 gene was highly conservative in the evolutionary process.Real-time quantitative PCR results showed that AQP9 gene expressed in buffalo liver,lung,brain,skin,testis and ovary tissues with different levels,had the most abundant expression in liver,followed by in skin and testis,less observed in lung and ovary.The results of immunohistochemical staining showed that the expression of AQP9 protein varied with the development of buffalo ovarian tissue,and gradually enhanced with follicle development.In testicular tissue,AQP9 protein expressed in spermatocyte and leydig cells of developmental stage testis.These results indicated that we had successfully cloned buffalo AQP9 gene sequences.The expression and its function of AQP9 in buffalo ovaries and testes might play an important role in follicle development and spermatogenesis.     

Immunolocalization of Aquaporins 1 and 9 in the Ram Efferent Ducts and Epididymis

Aquaporins (AQPs) are essential membrane protein channels for the transport of water across membranes. Fluid movement in the epididymis is important for modulation of the luminal environment, in which sperm mature and reside. This study was designed to understand the morphology and localization of AQPs in ram efferent ducts (ED) and epididymis. For this purpose, the epididymis of seven animals were removed for histologic and immunohistochemical analyses. AQP1 immunoreactivity was observed in the apex of the ED, and AQP9 was found adjacent to the nuclei of the epithelial cells of the ED. The epithelial lining of ram epididymis is pseudostratified columnar and presents principal, basal, apical and narrow cells. In the initial segment (IS), a moderate reaction for AQP1 was observed in the apical cytoplasm of epithelial cells. An intense reactivity for AQP1 was noted over the microvilli of principal cells and in spermatozoa in the caput. In the corpus and cauda, AQP1 was noted only over the endothelial cells of vascular channels located in intertubular spaces. A weak‐to‐moderate reaction for AQP9 was observed in the nuclei of epithelial cells in the IS, caput and corpus of the epididymis. In the cauda, an intense reaction to AQP9 was observed in the epithelial border. In the IS, caput and corpus, the reactivity for AQP9 differed from those observed in domestic animals. The cauda showed a pattern similar to that previously described. These results indicate that AQPs 1 and 9 have reversed locations and roles in rams, suggesting activity variations related with fluid and solute absorption throughout the epididymis.     

Immunolocalization of Aquaporin Water Channels in the Domestic Cat Male Genital Tract

Four different aquaporins (AQP1, 2, 5 and 9), integral membrane water channels that facilitate rapid passive movement of water, were immuno‐localized in the excurrent ducts collected from sexually mature cats during orchiectomy. Aquaporins 1, 2 and 9, were immuno‐localized at distinct levels, whereas AQP5 was undetectable all along the feline genital tract. No immunoreactivity was present at the level of the rete testis with any of the antibodies tested. In the efferent ducts, AQP1‐immunoreactivity was strongly evidenced at the apical surface of the non‐ciliated cells, and AQP9‐immunoreactivity was shown at the periphery of both ciliated and non‐ciliated cells. Aquaporins 2 was absent in the caput epididymidis, either in the efferent ducts or in the epididymal duct. Otherwise, AQP2 was increasingly localized at the adluminal surface of principal cells from the corpus to the cauda epididymidis and more weakly in the vas deferens epithelium. The supranuclear zone of the epididymal principal cells was AQP9‐immunoreactive throughout the duct, with the exclusion of the vacuolated sub‐region of the caput and with higher reaction intensity in the cauda region. AQP1 was present in the blood vessels all along the genital tract. AQP1 was expressed also in the smooth muscle layer of the vas deferens. The tested AQP molecules showed a different expression pattern in comparison with laboratory mammals, primates and the dog, unique other carnivore species studied to date. The present information is possibly useful in regard to the regional morphology of the feline epididymis and correlated functions, which are still a matter of debate.