iCre recombinase expressed in the anti-Müllerian hormone receptor 2 gene causes global genetic modification in the mouse†

Granulosa cell death is a significant contributor to DNA-damaging chemotherapy-induced ovarian insufficiency†

Typically, DNA-damaging chemotherapy (CTx) regimens have a gonadotoxic effect and cause premature ovarian insufficiency (POI), characterized by infertility and estrogen deficiency. However, whether loss of granulosa cells killed directly by CTx contributes significantly to POI has not been determined. To address this issue, we used a previously established mouse model of CTx-induced POI. The alkylating drugs Busulfan (8.75 mg/kg) and Cyclophosphamide (100 mg/kg) were administered to 8-week-old FVB female mice by intraperitoneal (IP) injection three times at 48-h intervals, after which ovarian tissues were harvested and examined by immunofluorescence. The number of primordial follicles was significantly reduced at day (d)6, whereas the number of growing follicles was relatively unchanged. CTx led to DNA double strand breaks in both oocytes and granulosa cells based on the presence of γH2AX foci. However, markers of apoptosis predominantly labeled granulosa cells in growing follicles. We next examined the effect of inhibiting apoptosis in growing granulosa cells by generating Bak-/-Baxfx/fx; Cyp19a1Cre transgenic mice. On d10 after the first CTx, Bak-/-Baxfx/fx; Cyp19a1Cre ovaries had fewer apoptotic granulosa cells and more surviving follicles than controls. Furthermore, Bak-/-Baxfx/fx; Cyp19a1Cre mice showed better fertility than controls after CTx. Our data suggest that granulosa cell death is a significant contributor to follicle depletion and fertility loss after Cyclophosphamide and Busulfan.

Bibliometric analysis of the research on anti-Müllerian hormone and polycystic ovary syndrome: current status, hotspots, and trends

Background

Polycystic Ovary Syndrome (PCOS) is a common endocrine and metabolic disorder affecting women of reproductive age. Over the past 30 years, significant efforts have been devoted to exploring its various pathogenic mechanisms, physiological and pathological characteristics, and biomarkers. Among these, Anti-Müllerian Hormone (AMH), as a biomarker for PCOS, is a significant biomarker for diagnosing, treating, and monitoring. However, the individual key information extracted from numerous studies is difficult to apply in clinical practice. Therefore, this article employs bibliometric analysis to summarize the current state of knowledge and offer future perspectives.

Methods

The Science Citation Index Expanded (SCI-E) within the Web of Science Core Collection database has been identified as the material source for obtaining articles related to AMH and PCOS. Software such as Origin, Microsoft Excel, Pajek, VOSviewer, and CiteSpace were used for bibliometric analysis and statistical assessment, evaluating countries, institutions, journals, references, and authors, as well as for constructing visual knowledge network maps.

Results

From 1994 to 2024, a total of 1,082 articles were included in the bibliometric analysis of research on AMH and PCOS. The number of publications in this field has consistently increased, with contributions from 70 countries, 1,363 institutions, and 5,144 researchers worldwide. Among them, the United States and China are the two countries with the highest number of publications. Zhejiang University, Monash University, and Peking University rank among the top three institutions exhibiting explosive citation bursts. The author with the highest publication volume is Didier Dewailly. The predictive keywords associated with these articles include "consensus," "morphology," "criteria," "prevalence," and "Müllerian hormone."

Conclusions

Through bibliometric analysis, this study has identified the primary research hotspots in the field of AMH and PCOS as follows: (1) Refining the diagnostic criteria for PCOS by using AMH as a biomarker; (2) Exploring the molecular role of AMH in the pathophysiological processes of various PCOS phenotypes and its potential as a therapeutic target; (3) Analyzing the impact of baseline AMH levels on female reproductive health and other biomarkers; (4) Investigating the signalling mechanisms of AMH in PCOS and its role in disease progression.

Revolutionizing Implantation Studies: Uterine-Specific Models and Advanced Technologies

Implantation is a complex and tightly regulated process essential for the establishment of pregnancy. It involves dynamic interactions between a receptive uterus and a competent embryo, orchestrated by ovarian hormones such as estrogen and progesterone. These hormones regulate proliferation, differentiation, and gene expression within the three primary uterine tissue types: myometrium, stroma, and epithelium. Advances in genetic manipulation, particularly the Cre/loxP system, have enabled the in vivo investigation of the role of genes in a uterine compartmental and cell type-specific manner, providing valuable insights into uterine biology during pregnancy and disease. The development of endometrial organoids has further revolutionized implantation research. They mimic the native endometrial structure and function, offering a powerful platform for studying hormonal responses, implantation, and maternal-fetal interactions. Combined with omics technologies, these models have uncovered the molecular mechanisms and signaling pathways that regulate implantation. This review provides a comprehensive overview of uterine-specific genetic tools, endometrial organoids, and omics. We explore how these advancements enhance our understanding of implantation biology, uterine receptivity, and decidualization in reproductive research.

History of Tspo deletion and induction in vivo: Phenotypic outcomes under physiological and pathological situations

The mitochondrial translocator protein (TSPO) is an outer mitochondrial protein membrane with high affinity for cholesterol. It is expressed in most tissues but is more particularly enriched in steroidogenic tissues. TSPO is involved in various biological mechanisms and TSPO regulation has been related to several diseases. However, despite a considerable number of published studies interested in TSPO over the past forty years, the precise function of the protein remains obscure. Most of the functions attributed to TSPO have been identified using pharmacological ligands of this protein, leading to much debate about the accuracy of these findings. In addition, research on the physiological role of TSPO has been hampered by the lack of in vivo deletion models. Studies to perform genetic deletion of Tspo in animal models have long been unsuccessful, which led to the conclusions that the deletion was deleterious and the gene essential to life. During the last decades, thanks to the significant technical advances allowing genome modification, several models of animal genetically modified for TSPO have been developed. These models have modified our view regarding TSPO and profoundly improved our fundamental knowledge on this protein. However, to date, they did not allow to elucidate the precise molecular function of TSPO and numerous questions persist concerning the physiological role of TSPO and its future as a therapeutic target. This article chronologically reviews the development of deletion and induction models of TSPO.

Normal Ovarian Function in Subfertile Mouse with Amhr2-Cre-Driven Ablation of Insr and Igf1r

Insulin receptor signaling promotes cell differentiation, proliferation, and growth which are essential for oocyte maturation, embryo implantation, endometrial decidualization, and placentation. The dysregulation of insulin signaling in women with metabolic syndromes including diabetes exhibits poor pregnancy outcomes that are poorly understood. We utilized the Cre/LoxP system to target the tissue-specific conditional ablation of insulin receptor (Insr) and insulin-like growth factor-1 receptor (Igf1r) using an anti-Mullerian hormone receptor 2 (Amhr2) Cre-driver which is active in ovarian granulosa and uterine stromal cells. Our long-term goal is to examine insulin-dependent molecular mechanisms that underlie diabetic pregnancy complications, and our conditional knockout models allow for such investigation without confounding effects of ligand identity, source and cross-reactivity, or global metabolic status within dams. Puberty occurred with normal timing in all conditional knockout models. Estrous cycles progressed normally in Insrd/d females but were briefly stalled in diestrus in Igf1rd/d and double receptor (DKO) mice. The expression of vital ovulatory genes (Lhcgr, Pgr, Ptgs2) was not significantly different in 12 h post-hCG superovulated ovaries in knockout mice. Antral follicles exhibited an elevated apoptosis of granulosa cells in Igf1rd/d and DKO mice. However, the distribution of ovarian follicle subtypes and subsequent ovulations was normal in all insulin receptor mutants compared to littermate controls. While ovulation was normal, all knockout lines were subfertile suggesting that the loss of insulin receptor signaling in the uterine stroma elicits implantation and decidualization defects responsible for subfertility in Amhr2-Cre-derived insulin receptor mutants.

Mechanisms of Regeneration and Fibrosis in the Endometrium

The uterine lining (endometrium) regenerates repeatedly over the life span as part of its normal physiology. Substantial portions of the endometrium are shed during childbirth (parturition) and, in some species, menstruation, but the tissue is rapidly rebuilt without scarring, rendering it a powerful model of regeneration in mammals. Nonetheless, following some assaults, including medical procedures and infections, the endometrium fails to regenerate and instead forms scars that may interfere with normal endometrial function and contribute to infertility. Thus, the endometrium provides an exceptional platform to answer a central question of regenerative medicine: Why do some systems regenerate while others scar? Here, we review our current understanding of diverse endometrial disruption events in humans, nonhuman primates, and rodents, and the associated mechanisms of regenerative success and failure. Elucidating the determinants of these disparate repair processes promises insights into fundamental mechanisms of mammalian regeneration with substantial implications for reproductive health.