Department of Animal and Food Sciences, University of Kentucky, Lexington, KY 40546, USA.
J Anim Sci. 2022 Jul 1;100(7). doi: 10.1093/jas/skac135.
Widespread regions of the southeast United States have soils, and hence forages, deficient in selenium (Se), necessitating Se supplementation to grazing cattle for optimal immune function, growth, and fertility. We have reported that supplementation with an isomolar 1:1 mix (MIX) of inorganic (ISe) and organic (OSe) forms of Se increases early luteal phase (LP) progesterone (P4) above that in cows on ISe alone. Increased early LP P4 advances embryonic development. Our objective was to determine the effect of form of Se on the transcriptome of the early LP corpus luteum (CL) with the goal of elucidating form of Se-regulated processes affecting luteal steroidogenesis and function. Non-lactating, 3-yr-old Angus-cross cows underwent 45-d Se-depletion, then repletion periods, and then at least 90 d of supplementation (TRT) with 35 ppm Se/d as either ISe (n = 5) or MIX (n = 5). CL were then recovered on day 7 of the estrous cycle, total RNA isolated, and the effect of TRT on the luteal transcriptome evaluated using bovine gene 1.0 ST arrays (Affymetrix, Inc., Santa Clara, CA). The abundance of transcripts in each CL was subjected to one-way ANOVA using Partek Genomic Suite software to determine TRT effects. Microarray analysis indicated a total of 887 transcripts that were differentially expressed and functionally annotated, with 423 and 464 up- and down-regulated (P < 0.05) in MIX vs. ISe CL, respectively. Bioinformatic analysis (Ingenuity Pathway Analysis) revealed the top TRT-affected canonical pathways to include seven specific to cholesterol biosynthesis and two to inflammatory responses. Results from the microarray analysis were corroborated by targeted real-time PCR. MIX CL had increased (P < 0.05) abundance of transcripts regulating cholesterol biosynthesis including DHCR7, DHCR24, and CYP51A1 (fold changes of 1.65, 1.48, and 1.40, respectively), suggesting MIX-induced increases in P4 to be due, in part, to increased availability of substrate to luteal cells. In addition, MIX CL had increased (P < 0.05) abundance of immune-response transcripts including C1QC, FAS, ILR8B, and IL1R1 (fold changes of 2.30, 1.74, 1.66, and 1.63, respectively). SREBF1 mRNA was also increased (1.32-fold, P < 0.05) in the MIX CL, which increases cholesterol synthesis and stimulates IL1B, linking effects of form of supplemental Se (TRT) on cholesterol biosynthesis and immune function in the CL.
美国东南部的广泛地区的土壤，以及因此饲料，硒（硒）缺乏，需要对放牧牛补充硒，以实现最佳的免疫功能、生长和繁殖。我们已经报告说，补充等摩尔 1:1 混合物（MIX）的无机（ISe）和有机（OSe）形式的硒可以增加早期黄体期（LP）孕酮（P4），高于单独使用 ISe 的牛。增加早期 LP P4 可促进胚胎发育。我们的目的是确定硒的形式对早期 LP 黄体（CL）转录组的影响，目标是阐明影响黄体甾体生成和功能的硒调节过程的形式。非泌乳的 3 岁安格斯杂交奶牛经历了 45 天的硒耗竭，然后是补充期，然后至少 90 天用 35 ppm/d 的硒补充（TRT），作为 ISe（n = 5）或 MIX（n = 5）。然后在发情周期的第 7 天回收 CL，分离总 RNA，并使用牛基因 1.0 ST 阵列（Affymetrix，Inc.，Santa Clara，CA）评估 TRT 对黄体转录组的影响。使用 Partek Genomic Suite 软件对每个 CL 中转录物的丰度进行单向方差分析，以确定 TRT 效应。微阵列分析表明，共有 887 个转录物差异表达并进行了功能注释，其中 MIX 与 ISe CL 相比，分别有 423 和 464 个转录物上调（P < 0.05）和下调。生物信息学分析（Ingenuity Pathway Analysis）显示，受 TRT 影响最大的经典途径包括七个特定于胆固醇生物合成的途径和两个与炎症反应相关的途径。微阵列分析的结果得到了靶向实时 PCR 的证实。MIX CL 中调节胆固醇生物合成的转录物丰度增加（P < 0.05），包括 DHCR7、DHCR24 和 CYP51A1（倍数变化分别为 1.65、1.48 和 1.40），这表明 MIX 诱导的 P4 增加部分是由于黄体细胞中底物可用性增加。此外，MIX CL 中免疫反应转录物的丰度增加（P < 0.05），包括 C1QC、FAS、ILR8B 和 IL1R1（倍数变化分别为 2.30、1.74、1.66 和 1.63）。MIX CL 中的 SREBF1 mRNA 也增加（1.32 倍，P < 0.05），这增加了胆固醇的合成，并刺激了 IL1B，将补充硒（TRT）的形式对 CL 中的胆固醇生物合成和免疫功能的影响联系起来。
