Blitek Agnieszka, Szymanska Magdalena
Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, Tuwima 10, 10-748 Olsztyn, Poland.
Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, Tuwima 10, 10-748 Olsztyn, Poland.
Theriogenology. 2017 Oct 1;101:53-61. doi: 10.1016/j.theriogenology.2017.06.013. Epub 2017 Jun 13.
Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear receptor family of ligand-dependent transcription factors. PPARs are critical regulators of glucose homeostasis and lipid metabolism, and affect cell proliferation and differentiation. In the current study, we examined (1) the profiles of PPARA, PPARD, and PPARG mRNA expression and DNA binding activity in porcine conceptuses collected on Days 10-11 (spherical and tubular conceptuses), 11-12 (filamentous conceptuses), 13-14, and 15-16 (elongated conceptuses) of pregnancy, (2) the presence of PPARA, PPARD, and PPARG proteins in Days 10, 12, and 15 conceptuses. Moreover, we analyzed the abundance of retinoid X receptor (RXR; PPARs heterodimer partner) transcripts as well as the correlation between PPARs mRNA expression and the expression of genes important for and/or associated with elongation of porcine conceptuses: aromatase (CYP19A1), prostaglandin endoperoxide synthase 2 (PTGS2), glucose transporter 1 (SLC2A1), and interleukin 1B (IL1B). PPARA mRNA expression in conceptuses did not change during Days 10-14 of gestation, but was greater on Days 15-16 compared to Days 10-11 (P < 0.05). A considerable increase in PPARD and PPARG mRNA expression was observed in filamentous conceptuses from Days 11-12 compared to spherical and tubular conceptuses from Days 10-11 (P < 0.01), followed by a decrease on Days 13-14 and 15-16 (P < 0.05). PPARA, PPARD, and PPARG proteins were present in conceptus tissue demonstrating nuclear localization clearly visible on Days 12 and 15 of pregnancy. DNA binding activity of the PPARD isoform was greater in filamentous conceptuses from Days 11-12 than in spherical and tubular conceptuses from Days 10-11 (P < 0.01). Moreover, concentrations of active PPARD and PPARG proteins in nuclear fractions of conceptus tissue were greater on Days 11-12 compared to Days 13-14 and 15-16 of pregnancy (P < 0.05). RXRA, RXRD, and RXRG mRNA expression in conceptuses increased on Days 11-12 compared to Days 10-11 (P < 0.05). PPARD and PPARG mRNA expression showed strong positive correlations with PTGS2 mRNA expression (P < 0.0001). Additionally, PPARD gene expression correlated with SLC2A1 and IL1B mRNA expression (P < 0.01). Collectively, these results indicate that among all three PPARs expressed in peri-implantation porcine conceptuses, PPARD and PPARG may be involved in conceptus elongation before implantation.
过氧化物酶体增殖物激活受体（PPARs）是配体依赖性转录因子核受体家族的成员。PPARs是葡萄糖稳态和脂质代谢的关键调节因子，并影响细胞增殖和分化。在本研究中，我们检测了：（1）妊娠第10 - 11天（球形和管状孕体）、11 - 12天（丝状孕体）、13 - 14天以及15 - 16天（伸长孕体）收集的猪孕体中PPARA、PPARD和PPARG mRNA表达谱及DNA结合活性；（2）第10、12和15天孕体中PPARA、PPARD和PPARG蛋白的存在情况。此外，我们分析了维甲酸X受体（RXR；PPARs异源二聚体伴侣）转录本的丰度，以及PPARs mRNA表达与对猪孕体伸长重要和/或相关的基因表达之间的相关性：芳香化酶（CYP19A1）、前列腺素内过氧化物合酶2（PTGS2）、葡萄糖转运蛋白1（SLC2A1）和白细胞介素1B（IL1B）。孕体中PPARA mRNA表达在妊娠第10 - 14天期间没有变化，但与第10 - 11天相比，在第15 - 16天更高（P < 0.05）。与第10 - 11天的球形和管状孕体相比，在第11 - 12天的丝状孕体中观察到PPARD和PPARG mRNA表达显著增加（P < 0.01），随后在第13 - 14天和15 - 16天下降（P < 0.05）。PPARA、PPARD和PPARG蛋白存在于孕体组织中，在妊娠第12天和15天可见明显的核定位。第11 - 12天丝状孕体中PPARD亚型的DNA结合活性高于第10 - 11天的球形和管状孕体（P < 0.01）。此外，与妊娠第13 - 14天和15 - 16天相比，孕体组织核组分中活性PPARD和PPARG蛋白的浓度在第11 - 12天更高（P < 0.05）。与第10 - 11天相比，孕体中RXRA、RXRD和RXRG mRNA表达在第11 - 12天增加（P < 0.05）。PPARD和PPARG mRNA表达与PTGS2 mRNA表达呈强正相关（P < 0.0001）。此外，PPARD基因表达与SLC2A1和IL1B mRNA表达相关（P < 0.01）。总体而言，这些结果表明，在着床前期猪孕体中表达的所有三种PPARs中，PPARD和PPARG可能在着床前参与孕体伸长。
