doppler-ultrasonography-for-live-imaging-quantification-ovarian

Doppler Ultrasonography for Live Imaging and Quantification of Ovarian Vascular Function in Mice

To effectively assess ovarian vascular function and understand its role in ovarian physiology and pathology, non-invasive in vivo approaches are essential ...

Cornell University

Hormones produced by the anterior pituitary gland regulate an array of important physiological functions, but pituitary hormone disorders are not fully understood. Herein we report that genetically-engineered mice with deletion of the hedgehog signaling receptor Patched1 by S100a4 promoter-driven Cre recombinase (S100a4-Cre;Ptch1fl/fl mutants) exhibit adult-onset hypogonadotropic hypogonadism and multiple pituitary hormone disorders. During the transition from puberty to adult, S100a4-Cre;Ptch1fl/fl mice of both sexes develop hypogonadism coupled with reduced gonadotropin levels. Their pituitary glands also display severe structural and functional abnormalities, as revealed by transmission electron microscopy and expression of key genes regulating pituitary endocrine functions. S100a4-Cre activity in the anterior pituitary gland is restricted to CD45+ cells of hematopoietic origin, including folliculo-stellate cells and other immune cell types, causing sex-specific changes in the expression of genes regulating the local microenvironment of the anterior pituitary. These findings provide in vivo evidence for the importance of pituitary hematopoietic cells in regulating fertility and endocrine function, in particular during sexual maturation and likely through sexually dimorphic mechanisms. These findings support a previously unrecognized role of hematopoietic cells in causing hypogonadotropic hypogonadism and provide inroads into the molecular and cellular basis for pituitary hormone disorders in humans.

S100a4-Cre-mediated deletion of Patched1 causes hypogonadotropic hypogonadism: role of pituitary hematopoietic cells in endocrine regulation.

We recently identified ~ 10,000 correlated regions of systemic interindividual epigenetic variation (CoRSIVs) in the human genome. These methylation variants are amenable to population studies, as DNA methylation measurements in blood provide information on epigenetic regulation throughout the body. Moreover, establishment of DNA methylation at human CoRSIVs is labile to periconceptional influences such as nutrition. Here, we analyze publicly available whole-genome bisulfite sequencing data on multiple tissues of each of two Holstein cows to determine whether CoRSIVs exist in cattle.

Systemic interindividual DNA methylation variants in cattle share major hallmarks with those in humans.

The preovulatory luteinizing hormone (LH) surge orchestrates complex cellular and molecular events leading to ovulation. CCAAT/enhancer-binding proteins α and β (C/EBPα/β) are transcription factors acutely induced by the LH surge and crucial for ovulation and granulosa cell luteinization. However, biological processes (BPs) and their regulatory mechanisms downstream of C/EBPα/β in the preovulatory ovary are not completely understood. To address this knowledge gap, we generated Cebpa/bfl/fl;Pgr-Cre mutants and compared them with Cebpa/bfl/fl;Cyp19a1-Cre mutant female mice: Cebpa/bfl/fl;Cyp19a1-Cre mutants have undetectable levels of C/EBPα/β throughout the preovulatory stages and do not ovulate, aligning with previous reports; and Cebpa/bfl/fl;Pgr-Cre mutants present gradual depletion of C/EBPα/β during the late preovulatory stage and a reduced ovulation rate. Comparison of these two models indicates that sustained expression of C/EBPα/β throughout the preovulatory stages is necessary for successful ovulation and provides a unique opportunity to interrogate gene regulatory mechanisms by C/EBPα/β during different preovulatory time windows and the effect of dysregulating C/EBPα/β on ovulation-associated BPs. Our study revealed that C/EBPα/β regulate gene expression and distinct biological functions such as vascular remodeling via dose- and preovulatory stage-dependent mechanisms. These findings shed new light on the intricate mechanisms of gene regulation by C/EBPα/β downstream of the LH surge.

CCAAT/Enhancer-Binding Proteins α and β Regulate Ovulation and Gene Expression via Dose- and Stage-Dependent Mechanisms.

Cumulus removal (CR), the removal of the small protective granulosa cells that surround an oocyte, is a crucial step in assisted reproductive technologies (ART). Traditional CR methods rely on vortexing or manual pipetting, which can result in inconsistencies and variability. Here, we present an open-surface platform featuring pillars that actively separates differently sized particles and removes cumulus cells from oocytes through vibration-induced flow (VIF). The platform removed 99% of small particles from the loading chamber by generating a local flow through the pillar array and separating smaller particles from larger particles. The platform was then used to remove cumulus cells from oocytes. CR under different actuation powers, time exposures, and hyaluronidase (HA) concentrations was optimized. The CR of up to 23 oocytes was accomplished simultaneously without any oocyte loss. Finally, mouse cumulus-oocyte complexes (COCs) were inseminated and CR was performed using both manual pipetting (control) and VIF. No statistical difference was observed in the fertilization and blastocyst rates, which were 90.7%, and 50.0% using manual pipetting, respectively, and 93.1% and 43.1% using VIF respectively. This platform automates CR process and reduces the technical manual labor involved in ART, paving the way for standardization and consistency within ART protocols.

Article	Year
S100a4-Cre-mediated deletion of Patched1 causes hypogonadotropic hypogonadism: role of pituitary hematopoietic cells in endocrine regulation. JCI insight\| PubMed ID: 31265437	2019
Systemic interindividual DNA methylation variants in cattle share major hallmarks with those in humans. Genome biology\| PubMed ID: 39004763	2024
CCAAT/Enhancer-Binding Proteins α and β Regulate Ovulation and Gene Expression via Dose- and Stage-Dependent Mechanisms. Endocrinology\| PubMed ID: 40294160	2025
On-chip oocyte cumulus removal using vibration-induced flow. Lab on a chip\| PubMed ID: 40977337	2025

Yi Athena Ren

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