Mitochondrial energy metabolism is downregulated in repeated implantation failure patients related to alteration of PGC-1α acetylation level.

Herein we aimed at exploring mitochondrial energy metabolism status in patients with repeated implantation failure (RIF) and whether key regulatory factor PGC-1α of energy metabolism is involved in the decidualization of endometrial stromal cells. Mitochondrial oxidative phosphorylation level and ATP synthesis were compared in primary endometrial stromal cells from RIF and control group. At the same time, as one of key transcription regulators of mitochondrial energy metabolism, the expression level and acetylation level of PGC-1α were compared with two groups. Then, we downregulated the acetylation levels of PGC-1α, and the expression of decidual markers (PRL and IGFBP1) was observed further. Mitochondrial energy metabolism, showing by mitochondrial oxidative phosphorylation level and ATP synthesis, was decreased in the endometrial stromal cells of the RIF group (RIF-hEnSCs). Meanwhile, PGC-1α acetylation levels were significantly higher in RIF-hEnSCs. When we reduced the acetylation levels of PGC-1α in RIF-hEnSCs, the basal O2 consumption rate and maximal respiration were increased, and also the PRL and IGFBP1. Overall, our data indicated that the endometrial stromal cells of the RIF patients had low level of mitochondrial energy metabolism. Reducing acetylation level of key energy metabolism regulator PGC-1α can increase the decidualization level of RIF-hEnSCs. These findings may inspire new ideas about the treatment of RIF.

Effect of luteinizing hormone concentration on transcriptome and subcellular organelle phenotype of ovarian granulosa cells.

RESEARCH QUESTION: Granulosa cells (GCs) surrounding oocytes are crucial for follicular growth, oocyte development, ovulation, and luteinization under the dynamic co-stimulation of follicle stimulating hormone (FSH) and luteinizing hormone (LH). This study aimed to investigate the effect of LH levels on GCs in preovulatory follicles under gonadotropin releasing hormone antagonist-based ovarian stimulation. In vitro experiments were also conducted to study the direct effect of LH on GCs. METHODS: Twelve infertile women were divided into low (L), medium (M), and high (H) LH groups according to their serum LH levels during ovarian stimulation. RNA-sequencing (RNA-seq) was conducted to examine the transcriptome profiles of GCs obtained from the above patients during the oocyte retrieval. The activity of mitochondrial dehydrogenase was measured under the stimulation of recombinant LH (rLH) concentration gradient combined with recombinant FSH. The ultrastructures of subcellular organelles were observed. RESULTS: Bioinformatic analyses showed that compared with the M group, molecule and pathway changes in the L group and in the H group were similar. In cultured GCs, both insufficient and excessive rLH impaired the activity of mitochondrial dehydrogenase. With the medium rLH concentration, numerous cell connections and abundant mitochondria and liposomes were observed. Compared with the medium concentration, GCs showed smaller and rounder mitochondria, more autophagosomes, and massive organelles damages with excessive rLH, and swollen, circular, or forked mitochondria were observed with inadequate rLH. CONCLUSIONS: RNA-seq provided a novel spectrum of transcriptome characteristics of GCs potentially affected by serum LH levels during ovarian stimulation. In vitro, rLH could directly affect GCs at the subcellular level.