Nio-Kobayashi Junko, Kudo Masataka, Sakuragi Noriaki, Iwanaga Toshihiko, Duncan W Colin
Laboratory of Histology and Cytology, Hokkaido University Graduate School of Medicine, Kita 15-Nishi 7, Kita-ku, Sapporo 060-8638, Japan.
Department of Reproductive Endocrinology and Oncology, Hokkaido University Graduate School of Medicine, Kita 15-Nishi 7, Kita-ku, Sapporo 060-8638, Japan.
Mol Hum Reprod. 2017 May 1;23(5):271-281. doi: 10.1093/molehr/gax011.
Do intraluteal prostaglandins (PG) contribute to luteal regulation in women?
Prostaglandin E (PGE), which is produced in human granulosa-lutein cells stimulated with luteotropic hCG, exerts similar luteotropic effects to hCG, and the expression of PG synthetic and metabolic enzymes in the human CL is driven toward less PGE but more prostaglandin F (PGF) during luteolysis.
Uterine PGF is a major luteolysin in many non-primate species but not in women. Increases in the PGF synthase, aldo-ketoreductase family one member C3 (AKR1C3), have been observed in the CL of marmoset monkeys during luteolysis. PGE prevents spontaneous or induced luteolysis in domestic animals.
STUDY DESIGN, SIZE, DURATION: Human CL tissues staged as the early-luteal (n = 6), mid-luteal (n = 6), late-luteal (n = 5) and menstrual (n = 3) phases were obtained at the time of hysterectomy for benign gynecological conditions. Luteinized granulosa cells (LGCs) were purified from follicular fluids obtained from patients undergoing assisted conception.
PARTICIPANTS/MATERIALS, SETTING, METHODS: Upon collection, one half of the CL was snap-frozen and the other was fixed with formalin and processed for immunohistochemical analysis of a PGE synthase (PTGES). Quantitative RT-PCR was employed to examine changes in the mRNA abundance of PG synthetic and metabolic enzymes, steroidogenic enzymes, and luteolytic molecules in the staged human CL and in human LGCs in vitro treated with hCG, PGE and PGF. A PGE withdrawal experiment was also conducted in order to reveal the effects of the loss of PGE in LGCs. Progesterone concentrations in the culture medium were measured.
The key enzyme for PGE synthesis, PTGES mRNA was abundant in the functional CL during the mid-luteal phase (P < 0.01), while mRNA abundance for genes involved in PGF synthesis (AKR1B1 and AKR1C1-3) increased in the CL during the late-luteal phase and menstruation (P < 0.05-0.001). PTGES mRNA expression positively correlated with that of 3β-hydroxysteroid dehydrogenase (HSD3B1; r = 0.7836, P < 0.001), while AKR1C3 expression inversely correlated with that of HSD3B1 (r = -0.7514, P = 0.0012) and PTGES (r = -0.6923, P = 0.0042). PGE exerted similar effects to hCG-promoting genes, such as steroidogenic acute regulatory protein (STAR) and HSD3B1, to produce progesterone and luteotropic PGE, suppress PGF synthetic enzymes and down-regulate luteolytic molecules such as βA- and βB-inhibin subunits (INHBA and INHBB) and bone morphogenetic proteins (BMP2, BMP4 and BMP6). PGE withdrawal resulted in reductions in the enzymes that produce progesterone (STAR; P < 0.001) and PGE (PTGES; P < 0.001), and the capacity to produce PGE decreased, while the capacity to produce PGF increased during the culture. The addition of PGF did not recapitulate the luteolytic effects of PGE withdrawal.
None.
LIMITATIONS, REASONS FOR CAUTION: Changes in mRNA expression of PG synthetic and metabolic enzymes may not represent actual increases in PGF during luteolysis in the CL. The effects of PGF on luteal cells currently remain unclear and the mechanisms responsible for decreases in the synthesis of PGE in vitro and at luteolysis have not been elucidated in detail.
The results obtained strongly support a luteotropic function of PGE in regulation of the human CL. They suggest that the main PG produced in human luteal tissue changes from PGE to PGF during the maturation and regression of the CL, and the loss of PGE is more important than the effects of PGF during luteolysis in women. This may be accompanied by reduced effects of LH/hCG in luteal cells, particularly decreased activation of cAMP/protein kinase A; however, the underlying mechanisms remain unknown.
STUDY FUNDING AND COMPETING INTEREST(S): This study was supported by the Cunningham Trust to WCD, a Postdoctoral Fellowship for Research Abroad from the Japan Society for the Promotion of Science and the Suntory Foundation for Life Sciences to J.N.-K.; W.C.D. is supported by an MRC Centre Grant G1002033 and a Scottish Senior Clinical Fellowship. The authors have nothing to disclose.
黄体期前列腺素（PG）对女性黄体功能的调节有作用吗？
促黄体生成素hCG刺激人颗粒黄体细胞产生的前列腺素E（PGE），与hCG具有相似的促黄体作用，并且在黄体溶解过程中，人黄体中PG合成和代谢酶的表达使得PGE减少，但前列腺素F（PGF）增多。
子宫PGF是许多非灵长类动物主要的黄体溶解素，但对女性并非如此。在狨猴黄体溶解期间，黄体中PGF合酶，即醛糖还原酶家族成员1C3（AKR1C3）有所增加。PGE可防止家畜自发性或诱发性黄体溶解。
研究设计、规模、持续时间：因良性妇科疾病行子宫切除术时，获取处于黄体早期（n = 6）、黄体中期（n = 6）、黄体晚期（n = 5）和月经期（n = 3）的人黄体组织。从接受辅助受孕患者的卵泡液中纯化黄体化颗粒细胞（LGCs）。
研究对象/材料、环境、方法：收集后，将一半黄体速冻，另一半用福尔马林固定并进行PGE合酶（PTGES）的免疫组化分析。采用定量RT-PCR检测分期人黄体以及体外经hCG、PGE和PGF处理的人LGCs中PG合成和代谢酶、类固醇生成酶及黄体溶解分子的mRNA丰度变化。还进行了PGE撤除实验，以揭示LGCs中PGE缺失的影响。测定培养基中的孕酮浓度。
PGE合成关键酶PTGES的mRNA在黄体中期功能性黄体中含量丰富（P < 0.01），而参与PGF合成的基因（AKR1B1和AKR1C1 - 3）的mRNA丰度在黄体晚期和月经期的黄体中增加（P < 0.05 - 0.001）。PTGES mRNA表达与3β - 羟基类固醇脱氢酶（HSD3B1）的表达呈正相关（r = 0.7836，P < 0.001），而AKR1C3表达与HSD3B1（r = -0.7514，P = 0.0012）和PTGES（r = -0.6923，P = 0.0042）呈负相关。PGE对促进基因表达具有与hCG相似的作用，如类固醇生成急性调节蛋白（STAR）和HSD3B1，以产生孕酮和促黄体PGE，抑制PGF合成酶并下调黄体溶解分子，如βA和βB抑制素亚基（INHBA和INHBB）以及骨形态发生蛋白（BMP2、BMP4和BMP6）。撤除PGE导致产生孕酮（STAR；P < 0.001）和PGE（PTGES；P < 0.001）的酶减少，产生PGE的能力下降，而培养过程中产生PGF的能力增加。添加PGF并未重现撤除PGE的黄体溶解作用。
无。
局限性、谨慎理由：PG合成和代谢酶的mRNA表达变化可能并不代表黄体溶解过程中CL内PGF的实际增加。目前PGF对黄体细胞的作用尚不清楚，体外及黄体溶解时PGE合成减少的机制也未详细阐明。
所得结果有力地支持了PGE在调节人黄体功能方面的促黄体作用。结果表明，在黄体成熟和退化过程中，人黄体组织中产生的主要PG从PGE转变为PGF，并且在女性黄体溶解过程中，PGE的缺失比PGF的作用更重要。这可能伴随着黄体细胞中LH/hCG作用的降低，特别是cAMP/蛋白激酶A的激活减少；然而，潜在机制尚不清楚。
本研究由坎宁安信托基金资助W.C.D.，日本学术振兴会海外博士后研究奖学金以及三得利生命科学基金会资助J.N.-K.；W.C.D.得到医学研究委员会中心基金G1002033和苏格兰高级临床研究奖学金的支持。作者无利益冲突需披露。
