John S. Davis

The establishment of pregnancy in ruminants is dependent on the production of interferon-tau by the conceptus which stimulates the production of interferon-stimulated gene 15 in maternal tissues. Interferon-stimulated gene 15 covalently binds to (ISGylation) and regulates intracellular proteins processes in a manner like ubiquitin. The aim of this study was to identify ISGylated proteins and infer their specific functions and biochemical pathways within endometrium. Endometrium was collected from pregnant ewes on Day 17 (P17, n = 4), synchronized non-inseminated ewes on Day 10 (EC10, n = 4) and Day 17 (EC17, n = 4) after estrus (Day 0). In addition, bovine endometrial cells were cultured with 10 ng/ml of recombinant bovine interferon-tau for 24 h. ISGylated proteins in protein extracts were immunoprecipitated with anti-bovine interferon-stimulated gene 15 antibody. The ISGylated proteins in eluates were identified using liquid chromatography–tandem mass spectrometry and confirmed by reciprocal immunoprecipitation of selected ISGylated proteins. Seventy-five ISGylated proteins were differentially expressed in the endometrium of EC10, EC17, and P17 ewes. Ingenuity pathway analysis indicated that interferon α/β signaling, interferon-stimulated gene 15 antiviral mechanism, Glycolysis I, and Gluconeogenesis I pathways were the most highly significant pathways induced in the pregnant endometrium. Enrichment of the ISGylated proteins STAT1, MX1, and enolase 1 was achieved by immunoprecipitation with specific antibodies and their conjugation to interferon-stimulated gene 15 was confirmed. The ISGylated endometrial proteins identified in pregnant ovine endometrium may function in interferon signaling, antiviral mechanisms, and glucose metabolism with implications for these pathways in the preparation of endometrium for successful implantation and maintenance of pregnancy.

The most notable progress in renal clear cell carcinoma (ccRCC) in the past decades is the introduction of drugs targeting the VHL-HIF signaling pathway-associated angiogenesis. However, mechanisms underlying the development of VHL mutation-independent ccRCC are unclear. Here we provide evidence that the disrupted Hippo-YAP signaling contributes to the development of ccRCC independent of VHL alteration. We found that YAP1 and its primary target genes are frequently upregulated in ccRCC and the upregulation of these genes is associated with unfavorable patient outcomes. Research results derived from our in vitro and in vivo experimental models demonstrated that, under normoxic conditions, hyperactivated YAP1 drives the expression of FGFs to stimulate the proliferation of tumor and tumor-associated endothelial cells in an autocrine/paracrine manner. When rapidly growing cancer cells create a hypoxic environment, hyperactivated YAP1 in cancer cells induces the production of VEGF, which promotes the angiogenesis of tumor-associated endothelial cells, leading to improved tumor microenvironment and continuous tumor growth. Our study indicates that hyperactivated YAP1 is essential for maintaining ccRCC progression, and targeting the dual role of hyperactivated YAP1 represents a novel strategy to improve renal carcinoma therapy.

Uterine leiomyoma or fibroids are prevalent noncancerous tumors of the uterine muscle layer, yet their origin and development remain poorly understood. We analyzed RNA expression profiles of 15 epigenetic mediators in uterine fibroids compared to myometrium using publicly available RNA-seq data. To validate our findings, we performed RT-qPCR on a separate cohort of uterine fibroids targeting these modifiers confirming our RNA-seq data. We then examined protein profiles of key N6-methyladenosine (m⁶A) modifiers in fibroids and their matched myometrium, showing no significant differences in concordance with our RNA expression profiles. To determine RNA modification abundance, mRNA and small RNA from fibroids and matched myometrium were analyzed by UHPLC MS/MS identifying prevalent m⁶A and 11 other known modifiers. However, no aberrant expression in fibroids was detected. We then mined a previously published dataset and identified differential expression of m⁶A modifiers that were specific to fibroid genetic sub-type. Our analysis also identified m⁶A consensus motifs on genes previously identified to be dysregulated in uterine fibroids. Overall, using state-of-the-art mass spectrometry, RNA expression and protein profiles, we characterized and identified differentially expressed m⁶A modifiers in relation to driver mutations. Despite the use of several different approaches, we identified limited differential expression of RNA modifiers and associated modifications in uterine fibroids. However, considering the highly heterogenous genomic and cellular nature of fibroids, and the possible contribution of single molecule m⁶A modifications to fibroid pathology, there is a need for greater in-depth characterization of m⁶A marks and modifiers in a larger and diverse patient cohort.

Steroidogenic tissues contain cytosolic lipid droplets that are important for steroidogenesis. Perilipin 2 (PLIN2), a structural coat protein located on the surface of lipid droplets in mammalian cells, plays a crucial role in regulating lipid droplet formation and contributing to various cellular processes such as lipid storage and energy homeostasis. Herein, we examine the role that PLIN2 plays in regulating progesterone synthesis in the bovine corpus luteum. Utilizing gene array databases and Western blotting, we have delineated the expression pattern of PLIN2 throughout the follicular to luteal transition. Our findings reveal the presence of PLIN2 in both ovarian follicular and steroidogenic luteal cells, demonstrating an increase in its levels as follicular cells transition into the luteal phase. Moreover, the depletion of PLIN2 via siRNA enhanced progesterone production in small luteal cells, whereas adenovirus‐mediated overexpression of both PLIN2 and Perilipin 3 (PLIN3) induced an increase in cytosolic lipid droplet accumulation and decreased hormone‐induced progesterone synthesis in these cells. Lastly, in vivo administration of the luteolytic hormone prostaglandin F2α resulted in an upregulation of PLIN2 mRNA and protein expression, accompanied by a decline in serum progesterone. Our findings highlight the pivotal role of PLIN2 in regulating progesterone synthesis in the bovine corpus luteum, as supported by its dynamic expression pattern during the follicular to luteal transition and its responsiveness to luteotropic and luteolytic hormones. We suggest PLIN2 as a potential therapeutic target for modulating luteal function.

Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals that are resistant to biodegradation and are environmentally persistent. PFAS are found in many consumer products and are a major source of water and soil contamination. This study investigated the effects of an environmentally relevant PFAS mixture (perfluorooctanoic acid [PFOA], perfluorooctanesulfonic acid [PFOS], perfluorohexanesulfonic acid [PFHxS]) on the transcriptome and function of human granulosa cells (hGCs). Primary hGCs were harvested from follicular aspirates of healthy, reproductive-age women who were undergoing oocyte retrieval for in vitro fertilization. Liquid Chromatography with tandem mass spectrometry (LC/MS-MS) was performed to identify PFAS compounds in pure follicular fluid. Cells were cultured with vehicle control or a PFAS mixture (2 nM PFHxS, 7 nM PFOA, 10 nM PFOS) for 96 h. Analyses of cell proliferation/apoptosis, steroidogenesis, and gene expression were measured via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays/immunofluorescence, ELISA/western blotting, and RNA sequencing/bioinformatics, respectively. PFOA, PFOS, and PFHxS were detected in 100% of follicle fluid samples. Increased cell proliferation was observed in hGCs treated with the PFAS mixture with no impacts on cellular apoptosis. The PFAS mixture also altered steroid hormone synthesis, increasing both follicle-stimulating hormone-stimulated and basal progesterone secretion and concomitant upregulation of STAR protein. RNA sequencing revealed inherent differences in transcriptomic profiles in hGCs after PFAS exposure. This study demonstrates functional and transcriptomic changes in hGCs after exposure to a PFAS mixture, improving our knowledge about the impacts of PFAS exposures and female reproductive health. These findings suggest that PFAS compounds can disrupt normal granulosa cell function with possible long-term consequences on overall reproductive health.

Progesterone production by the corpus luteum is fundamental for establishing and maintaining pregnancy. The pituitary gonadotropin luteinizing hormone (LH) is recognized as the primary stimulus for luteal formation and progesterone synthesis, regardless of species. Previous studies demonstrated an elevation in abundance of genes related to glucose and lipid metabolism during the follicular to luteal transition. However, the metabolic phenotype of these highly steroidogenic cells has not been studied. Herein, we determined acute metabolic changes induced by LH in primary luteal cells and defined pathways required for progesterone synthesis. Untargeted metabolomics analysis revealed that LH induces rapid changes in vital metabolic pathways, including glycolysis, tricarboxylic acid (TCA) cycle, pentose phosphate pathway, de novo lipogenesis, and hydrolysis of phospholipids. LH stimulated glucose uptake, enhanced glycolysis, and flux of [U- ¹³ C ₆ ]-labeled glucose-derived carbons into metabolic branches associated with adenosine 5’-triphosphate (ATP) and NADH/NADPH production, synthesis of nucleotides, proteins, and lipids, glycosylation of proteins or lipids, and redox homeostasis. Selective use of small molecule inhibitors targeting the most significantly changed pathways, such as glycolysis, TCA cycle, and lipogenesis, uncovered cellular metabolic routes required for LH-stimulated steroidogenesis. Furthermore, LH via the protein kinase A (PKA) pathway triggered post- translational modification of acetyl-CoA carboxylase alpha (ACACA) and ATP citrate lyase (ACLY), enzymes involved in de novo synthesis of fatty acids. Inhibition of ACLY and fatty acid transport into mitochondria reduced LH-stimulated ATP, cAMP production, PKA activation, and progesterone synthesis. Taken together, these findings reveal novel hormone-sensitive metabolic pathways essential for maintaining LHCGR/PKA signaling and steroidogenesis in ovarian luteal cells. Significance: The establishment and maintenance of pregnancy require a well-developed corpus luteum, an endocrine gland within the ovary that produces progesterone. Although there is increased awareness of intracellular signaling events initiating the massive production of progesterone during the reproductive cycle and pregnancy, there are critical gaps in our knowledge of the metabolic and lipidomic pathways required for initiating and maintaining luteal progesterone synthesis. Here, we describe rapid, hormonally triggered metabolic pathways, and define metabolic targets crucial for progesterone synthesis by ovarian steroidogenic cells. Understanding hormonal control of metabolic pathways may help elucidate approaches for improving ovarian function and successful reproduction or identifying metabolic targets for developing nonhormonal contraceptives.

The process of follicle maturation leading to ovulation is a key milestone in female fertility. It is known that circulating lipids and cytokines play a role in the follicle’s ability to go through follicular maturation and the ovulatory processes. However, the specific mechanisms are not well understood. We posit that dysregulation of granulosa cells influences the ovarian environment, which tries to adapt by changing released lipids and cytokines to achieve follicular maturation. Eleven non-lactating adult females underwent estrus synchronization with two injections of PGF2α 14 days apart. Daily blood samples were collected for 28 days to monitor steroid hormone production after the second injection. To understand the potential impacts of lipids and cytokines during ovulation, a low-dose FSH stimulation (FSHLow) was performed after resynchronization of cows, and daily blood samples were collected for 14 days to monitor steroid hormone production until ovariectomies. The lipidomic analysis demonstrated increased circulating diacylglycerides and triacylglycerides during the mid-luteal phase and after FSHLow treatment. Cholesteryl esters decreased in circulation but increased in follicular fluid (FF) after FSHLow. Increased circulating concentrations of TNFα and reduced CXCL9 were observed in response to FSHLow. Therefore, specific circulating lipids and cytokines may serve as markers of normal follicle maturation.