Money T T, King R G, Wong M H, Stevenson J L, Kalionis B, Erwich J J H M, Huisman M A, Timmer A, Hiden U, Desoye G, Gude N M
Department of Pharmacology, Monash University, Clayton, Vic. 3800, Australia.
Placenta. 2007 May-Jun;28(5-6):429-36. doi: 10.1016/j.placenta.2006.08.002. Epub 2006 Oct 5.
Chloride channels regulate the movement of a major cellular anion and are involved in fundamental processes that are critical for cell viability. Regulation of intracellular chloride is achieved by multiple classes of channel proteins. One class of putative channels are the chloride intracellular channel (CLIC) family. Evidence suggests that several CLICs are expressed in human placenta, although their roles in this tissue are not certain. Northern blot analysis has shown that CLIC3 is highly expressed in placenta relative to other human tissues; however, its cellular distribution is not known. This study used microarray expression profiling to clarify which CLICs are expressed in human placenta and RT-PCR, Western blot and immunohistochemistry to determine the expression pattern of CLIC3 in human placenta and fetal membranes. Placentas and fetal membranes were obtained from term pregnancies after delivery and placental tissue was obtained from first trimester following either chorionic villous sampling or elective pregnancy termination. Trophoblast cells were isolated from first trimester and term placentas and placental endothelial cells were isolated from term placentas. Microarray expression profiling identified high expression of mRNA for CLICs 1, 3 and 4 in the isolated first trimester and term trophoblast cells. High mRNA expression in the isolated endothelial cells was also found for CLICs 1 and 4, but not CLIC3. Low expression was found for CLIC5 in all three types of isolated cells. RT-PCR confirmed that CLIC3 mRNA was expressed in trophoblast cells at both gestational ages, but was not present in endothelial cells. CLIC3 mRNA was also identified in whole placental extracts at both gestational ages and in term amnion and choriodecidua. Immunohistochemistry using a chicken anti-human CLIC3 antibody localised strong CLIC3-specific staining to the syncytiotrophoblast and villous cytotrophoblast cells in both first trimester and term placentas, and weaker staining in extravillous trophoblast cells in first trimester. In fetal membranes at term strong CLIC3-specific staining was localised to chorionic trophoblast cells, with weaker staining in amniotic epithelial and decidual cells. It was previously shown that chloride uptake was increased into cells that had been transfected with CLIC3. CLIC3 may facilitate chloride ion movement and the regulation of cellular processes associated with the movement of chloride in the placental and fetal membrane cells in which it is expressed.
氯离子通道调节主要细胞阴离子的移动，并参与对细胞生存能力至关重要的基本过程。细胞内氯离子的调节是通过多种类型的通道蛋白实现的。一类假定的通道是氯离子细胞内通道（CLIC）家族。有证据表明，几种CLIC在人胎盘中表达，尽管它们在该组织中的作用尚不确定。Northern印迹分析表明，相对于其他人体组织，CLIC3在胎盘中高度表达；然而，其细胞分布尚不清楚。本研究使用微阵列表达谱来阐明哪些CLIC在人胎盘中表达，并通过RT-PCR、蛋白质印迹和免疫组织化学来确定CLIC3在人胎盘和胎膜中的表达模式。胎盘和胎膜取自足月分娩后的妊娠，胎盘组织取自绒毛取样或选择性终止妊娠后的孕早期。从孕早期和足月胎盘中分离出滋养层细胞，从足月胎盘中分离出胎盘内皮细胞。微阵列表达谱鉴定出CLIC1、3和4的mRNA在分离的孕早期和足月滋养层细胞中高表达。在分离的内皮细胞中也发现CLIC1和4的mRNA高表达，但CLIC3不高。在所有三种类型的分离细胞中均发现CLIC5低表达。RT-PCR证实，CLIC3 mRNA在两个孕周的滋养层细胞中均有表达，但在内皮细胞中不存在。在两个孕周以及足月羊膜和绒毛蜕膜的全胎盘提取物中也鉴定出CLIC3 mRNA。使用鸡抗人CLIC3抗体的免疫组织化学将强烈的CLIC3特异性染色定位到孕早期和足月胎盘的合体滋养层和绒毛细胞滋养层细胞，而在孕早期的绒毛外滋养层细胞中染色较弱。在足月胎膜中，强烈的CLIC3特异性染色定位到绒毛膜滋养层细胞，在羊膜上皮和蜕膜细胞中染色较弱。先前的研究表明，转染了CLIC3的细胞对氯离子的摄取增加。CLIC3可能促进氯离子的移动以及与其所表达的胎盘和胎膜细胞中氯离子移动相关的细胞过程的调节。
