Gray C Allison, Dunlap Kathrin A, Burghardt Robert C, Spencer Thomas E
Center for Animal Biotechnology and Genomics and Department of Animal Science and Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX 77843, USA.
Reproduction. 2005 Aug;130(2):231-40. doi: 10.1530/rep.1.00637.
Galectin-15 is the newest member of a secreted beta-galactoside-binding lectin family. The galectin-15 gene is expressed specifically by the endometrial luminal epithelium (LE) and superficial ductal glandular epithelium (sGE) of the ovine uterus. The proposed extracellular role of secreted galec7tin-15 is to regulate implantation and placentation by functioning as a heterophilic cell adhesion molecule between the conceptus trophectoderm and endometrial LE, while that of intracellular galectin-15 is to regulate cell survival, differentiation and function. The present study determined galectin-15 expression in uteroplacental tissues during gestation and in the postpartum uterus. In the uterine lumen, secreted galectin-15 was found as multimers, particularly on days 14 and 16 of pregnancy. In the endometrial epithelium and conceptus trophectoderm, intracellular galectin-15 protein was found associated with crystalline structures. Between days 20 and 120 of pregnancy, galectin-15 mRNA was expressed specifically by the LE and sGE of the intercaruncular endometrium of ewes. Immunoreactive galectin-15 protein was most abundant in the trophectoderm with lower levels in the endometrial LE and sGE. Galectin-15 protein was detected in allantoic fluid, but not in amniotic fluid. After parturition, galectin-15 mRNA declined in the endometrium from postpartum day (PPD) 1 to 28 and exhibited a variegated expression pattern in the LE and sGE. These results indicate that galectin-15 is synthesized and secreted throughout gestation by the endometrial LE/sGE and is absorbed by the placenta and forms crystals within the trophectoderm, whereas the remainder is cleared into the allantois after being transported into the fetal circulation via the placental areolae. Based on the biological properties of other galectin family members, galectin-15 is hypothesized to have biological roles in conceptus-endometrial interactions, uterine immune and inflammatory responses, and placental morphogenesis and function.
半乳糖凝集素-15是分泌型β-半乳糖苷结合凝集素家族的最新成员。半乳糖凝集素-15基因在绵羊子宫的子宫内膜腔上皮（LE）和浅表导管腺上皮（sGE）中特异性表达。分泌型半乳糖凝集素-15在细胞外的作用被认为是通过作为孕体滋养外胚层和子宫内膜LE之间的异嗜性细胞粘附分子来调节着床和胎盘形成，而细胞内半乳糖凝集素-15的作用是调节细胞存活、分化和功能。本研究确定了妊娠期间子宫胎盘组织以及产后子宫中半乳糖凝集素-15的表达情况。在子宫腔内，分泌型半乳糖凝集素-15以多聚体形式存在，尤其是在妊娠第14天和第16天。在子宫内膜上皮和孕体滋养外胚层中，发现细胞内半乳糖凝集素-15蛋白与晶体结构相关。在妊娠第20天至120天之间，半乳糖凝集素-15 mRNA在母羊肉阜间子宫内膜的LE和sGE中特异性表达。免疫反应性半乳糖凝集素-15蛋白在滋养外胚层中含量最高，在子宫内膜LE和sGE中含量较低。在尿囊液中检测到了半乳糖凝集素-15蛋白，但羊水中未检测到。分娩后，从产后第1天到第28天，子宫内膜中的半乳糖凝集素-15 mRNA下降，并且在LE和sGE中呈现出多样化的表达模式。这些结果表明，半乳糖凝集素-15在整个妊娠期由子宫内膜LE/sGE合成并分泌，被胎盘吸收并在滋养外胚层内形成晶体，而其余部分在通过胎盘乳晕转运到胎儿循环后被清除到尿囊中。基于其他半乳糖凝集素家族成员的生物学特性，推测半乳糖凝集素-15在孕体-子宫内膜相互作用、子宫免疫和炎症反应以及胎盘形态发生和功能中具有生物学作用。
