Table_4_Label-Free Mass Spectrometry-Based Quantitative Proteomics Analysis of Serum Proteins During Early Pregnancy in Jennies (Equus asinus).xlsx

Early pregnancy in jennies is routinely determined by palpation per rectum or ultrasonography and also by detecting steroid hormone and chorionic gonadotropin levels in the blood, plasma, and serum. Herein we applied label-free mass spectrometry-based quantitative proteomics to identify serum proteins that were differentially expressed between early pregnant (day 45 after ovulation) and non-pregnant jennies. Bioinformatics analysis allowed illustration of pathways potentially involved in early pregnancy. We identified 295 proteins from a total of 2,569 peptides. Twenty-five proteins (22 upregulated and three downregulated) were significantly differentially expressed between the early pregnant and non-pregnant groups. The majority of the differentially expressed proteins were involved in defense response, early embryonic development, and hormone signaling pathways. Furthermore, functional protein analyses suggested that proteins were involved in binding, enzyme inhibitor activity, and enzyme regulator activity. Five serum proteins—granulin precursor/acrogranin, transgelin-2, fibronectin, fibrinogen-like 1, and thrombospondin 1—can be considered as novel, reliable candidates to detect pregnancy in jennies. To the best of our knowledge, this is the first study to use label-free mass spectrometry-based quantitative proteomics to analyze serum proteins during early pregnancy in jennies. Our results should facilitate the identification of valuable pregnancy diagnostic markers in early pregnant jennies.

早期母鸡妊娠的常规诊断方法包括直肠触诊、超声波检查以及通过检测血液、血浆和血清中的类固醇激素和绒毛膜促性腺激素水平。本研究中，我们应用了基于免标记质谱技术的定量蛋白质组学方法，以识别早期妊娠（排卵后第45天）与未妊娠母鸡血清中差异表达的蛋白质。生物信息学分析有助于阐述可能参与早期妊娠的通路。我们从2,569个肽段中鉴定出295种蛋白质。在早期妊娠组与未妊娠组之间，有25种蛋白质（22种上调，3种下调）表现出显著差异表达。大多数差异表达的蛋白质与防御反应、早期胚胎发育和激素信号通路相关。此外，功能蛋白质分析表明，这些蛋白质参与了结合、酶抑制剂活性和酶调节活性。五种血清蛋白——粒蛋白前体/表粒蛋白、转凝胶素-2、纤连蛋白、纤维蛋白原样1和血栓素蛋白1——可作为检测母鸡妊娠的全新、可靠的候选标记。据我们所知，这是首次利用基于免标记质谱技术的定量蛋白质组学分析母鸡早期妊娠血清蛋白质的研究。我们的研究结果应有助于识别早期妊娠母鸡中具有重要价值的妊娠诊断标志物。