Department of Cell Biology and Physiology, University of Kansas Medical Center, 3075 HLSIC, 3901 Rainbow Blvd., Kansas City, KS 66160, USA.
Department of Biostatistics and Data Science, University of Kansas Medical Center, Kansas City, MO 66160, USA.
Int J Mol Sci. 2023 Aug 23;24(17):13078. doi: 10.3390/ijms241713078.
Ovarian follicles undergo a series of dynamic changes following the ovulatory surge of luteinizing hormone including cumulus expansion, oocyte maturation, ovulation, and luteinization. Post-transcriptional gene regulatory events are critical for mediating LH follicular responses, and among all RNA isoforms, circular RNA (circRNA) is one of the most abundant forms present in cells, yet they remain the least studied. Functionally, circRNA can act as miRNA sponges, protein sponges/decoys, and regulators of transcription and translation. In the context of ovarian follicular development, the identity and roles of circRNA are relatively unknown. In the present study, high throughput RNA sequencing of granulosa cells immediately prior to and 4-h after the LH/hCG surge identified 42,381 circRNA originating from 7712 genes. A total of 54 circRNA were identified as differentially expressed between 0-h and 4-h time points (Fold Change ± 1.5, FDR ≤ 0.1), among them 42 circRNA were upregulated and 12 circRNA were downregulated. All differentially expressed circRNA between the 0-h and 4-h groups were subjected to circinteractome analysis and identified networks of circRNA-protein and circRNA-miRNA were further subjected to "micro-RNA target filter analysis" in Ingenuity Pathway Analyses, which resulted in the identification of miRNA targeted mRNAs. A comparison of these circRNA target mRNAs with LH-induced mRNAs identified Runx2, Egfr, Areg, Sult1el, Cyp19a1, Cyp11a1, and Hsd17b1 as targets of circKif2, circVcan, circMast4, and circMIIt10. These newly identified LH/hCG-induced circRNA, their target miRNA and protein networks provide new insights into the complex interactions associated with periovulatory follicular development.
卵巢卵泡在黄体生成素（LH）排卵峰后经历一系列动态变化，包括卵丘扩展、卵母细胞成熟、排卵和黄体化。转录后基因调控事件对于介导 LH 卵泡反应至关重要，在所有 RNA 异构体中，环状 RNA（circRNA）是细胞中最丰富的形式之一，但它们仍然是研究最少的。功能上，circRNA 可以作为 miRNA 海绵、蛋白海绵/诱饵和转录和翻译的调节剂。在卵巢卵泡发育的背景下，circRNA 的身份和作用相对未知。在本研究中，对 LH/hCG 峰前和峰后 4 小时的颗粒细胞进行高通量 RNA 测序，鉴定出 7712 个基因来源的 42381 个 circRNA。在 0 小时和 4 小时时间点之间，有 54 个 circRNA 被鉴定为差异表达（倍数变化±1.5， FDR≤0.1），其中 42 个 circRNA 上调，12 个 circRNA 下调。在 0 小时和 4 小时组之间差异表达的所有 circRNA 均进行 circinteractome 分析，并鉴定出 circRNA-蛋白和 circRNA-miRNA 网络，进一步在 Ingenuity Pathway Analyses 中进行“miRNA 靶标过滤分析”，结果鉴定出 miRNA 靶向的 mRNAs。将这些 circRNA 靶标 mRNAs 与 LH 诱导的 mRNAs 进行比较，鉴定出 Runx2、Egfr、Areg、Sult1el、Cyp19a1、Cyp11a1 和 Hsd17b1 是 circKif2、circVcan、circMast4 和 circMIIt10 的靶标。这些新鉴定的 LH/hCG 诱导的 circRNA、它们的靶 miRNA 和蛋白质网络为与排卵前卵泡发育相关的复杂相互作用提供了新的见解。
