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33
result(s) for
"Ko, CheMyong"
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Prenatal exposure to Di(2-ethylhexyl) phthalate and high-fat diet synergistically disrupts gonadal function in male mice
2024
Prenatal exposure to Di (2-ethylhexyl) phthalate (DEHP) impairs the reproductive system and causes fertility defects in male offspring. Additionally, high-fat (HF) diet is a risk factor for reproductive disorders in males. In this study, we tested the hypothesis that prenatal exposure to a physiologically relevant dose of DEHP in conjunction with HF diet synergistically impacts reproductive function and fertility in male offspring. Female mice were fed a control or HF diet 7 days prior to mating and until their litters were weaned on postnatal day 21. Pregnant dams were exposed to DEHP or vehicle from gestational day 10.5 until birth. The male offspring's gross phenotype, sperm quality, serum hormonal levels, testicular histopathology, and testicular gene expression pattern were analyzed. Male mice born to dams exposed to DEHP + HF had smaller testes, epididymides, and shorter anogenital distance compared with those exposed to HF or DEHP alone. DEHP + HF mice had lower sperm concentration and motility compared with DEHP mice. Moreover, DEHP + HF mice had more apoptotic germ cells, fewer Leydig cells, and lower serum testosterone levels than DEHP mice. Furthermore, testicular mRNA expression of Dnmt1 and Dnmt3a was two to eight-fold higher than in DEHP mice by qPCR, suggesting that maternal HF diet and prenatal DEHP exposure additively impact gonadal function by altering the degree of DNA methylation in the testis. These results suggest that the combined exposure to DEHP and high-fat synergistically impairs reproductive function in male offspring, greater than exposure to DEHP or HF diet alone. Summary Sentence The combined exposure to DEHP and high-fat synergistically impairs reproductive function in maleoffspring, greater than exposure to DEHP or HF diet alone. Graphical Abstract
Journal Article
Core Binding Factors are essential for ovulation, luteinization, and female fertility in mice
by
Jeon, Hayce
,
Choi, Yohan
,
Jo, Misung
in
631/337/572/2102
,
631/443/494/2732
,
692/699/2732/1577
2020
Core Binding Factors (CBFs) are a small group of heterodimeric transcription factor complexes composed of DNA binding proteins, RUNXs, and a non-DNA binding protein, CBFB. The LH surge increases the expression of
Runx1
and
Runx2
in ovulatory follicles, while
Cbfb
is constitutively expressed. To investigate the physiological significance of CBFs, we generated a conditional mutant mouse model in which granulosa cell expression of
Runx2
and
Cbfb
was deleted by the
Esr2Cre
. Female
Cbfb
flox/flox
;Esr2
cre/+
;Runx2
flox/flox
mice were infertile; follicles developed to the preovulatory follicle stage but failed to ovulate. RNA-seq analysis of mutant mouse ovaries collected at 11 h post-hCG unveiled numerous CBFs-downstream genes that are associated with inflammation, matrix remodeling, wnt signaling, and steroid metabolism. Mutant mice also failed to develop corpora lutea, as evident by the lack of luteal marker gene expression, marked reduction of vascularization, and excessive apoptotic staining in unruptured poorly luteinized follicles, consistent with dramatic reduction of progesterone by 24 h after hCG administration. The present study provides
in vivo
evidence that CBFs act as essential transcriptional regulators of both ovulation and luteinization by regulating the expression of key genes that are involved in inflammation, matrix remodeling, cell differentiation, vascularization, and steroid metabolisms in mice.
Journal Article
Estrogen receptor α in T cells suppresses follicular helper T cell responses and prevents autoimmunity
2019
Estrogen receptor alpha (ERα) is a sex hormone nuclear receptor that regulates various physiological events, including the immune response. Although there have been some recent studies on ERα regarding subsets of T cells, such as Th1, Th2, Th17, and Treg cells, its role in follicular helper T (TFH) cells has not yet been elucidated. To determine whether ERα controls TFH response and antibody production, we generated T cell-specific ERα knockout (KO) mice by utilizing the CD4-Cre/ERα flox system (CD4-ERα KO) and then analyzed their phenotype. At approximately 1 year of age, CD4-ERα KO mice spontaneously showed mild autoimmunity with increased autoantibody production and CD4
+
CD44
+
CXCR5
+
Bcl-6
+
TFH cells in the mesenteric lymph nodes and spleen. We next immunized 6–8-week-old CD4-ERα KO mice with sheep red blood cells (SRBCs), which resulted in an increased proportion of TFH cells and germinal center (GC) responses. In addition, 17β-estradiol (E2) treatment decreased TFH responses in wild-type mice and suppressed the mRNA expression of Bcl-6 and IL-21. Finally, we confirmed that the production of high-affinity antigen-specific antibodies and isotype class switching induced by NP-conjugated ovalbumin immunization were elevated in CD4-ERα KO mice under sufficient estrogen conditions. These results collectively demonstrate that the female sex hormone receptor ERα inhibits the TFH cell response and GC reaction to control autoantibody production, which was related to estrogen signaling and autoimmunity.
Autoimmune disease: the importance of estrogen
Estrogen signaling may play a crucial role in mediating autoimmune responses and preventing diseases such as rheumatoid arthritis. Estrogen plays vital roles in the female endocrine and reproductive systems, and its function is partly mediated by the estrogen receptor alpha (ERα). ERα-deficient mice have more severe autoimmune disease, suggesting a link between estrogen signaling and immune responses. Je-Min Choi at Hanyang University in Seoul, South Korea, and co-workers generated mice with T cells lacking ERα and followed their immune system development. They were particularly interested in monitoring follicular helper T cells (TFH), which help B cells generate antibodies in response to pathogen attack as well as self-antigen. The ERα-deficiency in T cells spontaneously developed mild autoimmune symptoms in mice, with increased levels of TFH and autoantibodies. Their results suggest ERα-mediated estrogen signaling in CD4 T cells is needed to suppress TFH activity and limit autoimmune disease development in female.
Journal Article
Beclin-1 deficiency in the murine ovary results in the reduction of progesterone production to promote preterm labor
by
Xiaoman Hong
,
Thomas R. Gawriluk
,
CheMyong Ko
in
animal ovaries
,
Animals
,
Apoptosis Regulatory Proteins - deficiency
2014
Significance The success of mammalian reproduction is contingent upon the production of hormones within the female to not only promote germ cell development, but to establish and maintain pregnancy. We demonstrate that abrogating autophagy, a cellular process to maintain energy stores, can lead to reproductive defects that prevent a successful pregnancy in mice. Females that lack the crucial autophagy gene Beclin1 ( Becn1 ) in the progesterone-producing cells of the ovary demonstrate reduced circulating progesterone and a preterm birth phenotype concurrent with the loss of litters, which is rescued by the administration of exogenous progesterone. Because progesterone is a necessary hormone for mammalian pregnancy, these data suggest that autophagy may play a role in steroidogenesis and, thus, in successful human reproduction.
Autophagy is an important cellular process that serves as a companion pathway to the ubiquitin-proteasome system to degrade long-lived proteins and organelles to maintain cell homeostasis. Although initially characterized in yeast, autophagy is being realized as an important regulator of development and disease in mammals. Beclin1 ( Becn1 ) is a putative tumor suppressor gene that has been shown to undergo a loss of heterozygosity in 40–75% of human breast, ovarian, and prostate cancers. Because Becn1 is a key regulator of autophagy, we sought to investigate its role in female reproduction by using a conditional knockout approach in mice. We find that pregnant females lacking Becn1 in the ovarian granulosa cell population have a defect in progesterone production and a subsequent preterm labor phenotype. Luteal cells in this model exhibit defective autophagy and a failure to accumulate lipid droplets needed for steroidogenesis. Collectively, we show that Becn1 provides essential functions in the ovary that are essential for mammalian reproduction.
Journal Article
Male animal sterilization: history, current practices, and potential methods for replacing castration
2024
Sterilization and castration have been synonyms for thousands of years. Making an animal sterile meant to render them incapable of producing offspring. Castration or the physical removal of the testes was discovered to be the most simple but reliable method for managing reproduction and sexual behavior in the male. Today, there continues to be global utilization of castration in domestic animals. More than six hundred million pigs are castrated every year, and surgical removal of testes in dogs and cats is a routine practice in veterinary medicine. However, modern biological research has extended the meaning of sterilization to include methods that spare testis removal and involve a variety of options, from chemical castration and immunocastration to various methods of vasectomy. This review begins with the history of sterilization, showing a direct link between its practice in man and animals. Then, it traces the evolution of concepts for inducing sterility, where research has overlapped with basic studies of reproductive hormones and the discovery of testicular toxicants, some of which serve as sterilizing agents in rodent pests. Finally, the most recent efforts to use the immune system and gene editing to block hormonal stimulation of testis function are discussed. As we respond to the crisis of animal overpopulation and strive for better animal welfare, these novel methods provide optimism for replacing surgical castration in some species.
Journal Article
Germline-dependent transmission of male reproductive traits induced by an endocrine disruptor, di-2-ethylhexyl phthalate, in future generations
2020
In males, defective reproductive traits induced by an exposure to an endocrine disruptor are transmitted to future generations via epigenetic modification of the germ cells. Interestingly, the impacted future generations display a wide range of heterogeneity in their reproductive traits. In this study, the role that the Y chromosome plays in creating such heterogeneity is explored by testing the hypothesis that the Y chromosome serves as a carrier of the exposure impact to future generations. This hypothesis implies that a male who has a Y chromosome that is from a male that was exposed to an endocrine disruptor will display a more severe reproductive phenotype than a male whose Y chromosome is from an unexposed male. To test this hypothesis, we used a mouse model in which F1 generation animals were exposed prenatally to an endocrine disruptor, di-2-ethylhexyl phthalate (DEHP), and the severity of impacted reproductive traits was compared between the F3 generation males that were descendants of F1 males (paternal lineage) and those from F1 females (maternal lineage). Pregnant dams (F0 generation) were exposed to the vehicle or 20 or 200 μg/kg/day of DEHP from gestation day 11 until birth. Paternal lineage F3 DEHP males exhibited decreased fertility, testicular steroidogenic capacity, and spermatogenesis that were more severely impaired than those of maternal lineage males. Indeed, testicular transcriptome analysis found that a number of Y chromosomal genes had altered expression patterns in the paternal lineage males. This transgenerational difference in the DEHP impact can be attributed specifically to the Y chromosome.
Journal Article
Effect of the spatial–temporal specific theca cell Cyp17 overexpression on the reproductive phenotype of the novel TC17 mouse
by
Harrison, Tracy N. H.
,
Swift, Joseph
,
Secchi, Christian
in
Androgen excess
,
Androgens
,
Androgens - pharmacology
2021
Background
In the ovarian follicle, the Theca Cells (TCs) have two main functions: preserving morphological integrity and, importantly, secreting steroid androgen hormones. TCs express the essential enzyme 17α-hydroxylase/17,20-desmolase (CYP17), which permits the conversion of pregnenolone and progesterone into androgens. Dysregulation of CYP17 enzyme activity due to an intrinsic ovarian defect is hypothesized to be a cause of hyperandrogenism in women. Androgen excess is observed in women with polycystic ovary syndrome (PCOS) resulting from excess endogenous androgen production, and in transgender males undergoing exogenous testosterone therapy after female sex assignment at birth. However, the molecular and morphological effects of
Cyp17
overexpression and androgen excess on folliculogenesis is unknown.
Methods
In this work, seeking a comprehensive profiling of the local outcomes of the androgen excess in the ovary, we generated a transgenic mouse model (TC17) with doxycycline (Dox)-induced
Cyp17
overexpression in a local and temporal manner. TC17 mice were obtained by a combination of the Tet-dependent expression system and the Cre/LoxP gene control system.
Results
Ovaries of Dox-treated TC17 mice overexpressed
Cyp17
specifically in TCs, inducing high testosterone levels. Surprisingly, TC17 ovarian morphology resembled the human ovarian features of testosterone-treated transgender men (partially impaired folliculogenesis, hypertrophic or luteinized stromal cells, atretic follicles, and collapsed clusters). We additionally assessed TC17 fertility denoting a perturbation of the normal reproductive functions (e.g., low pregnancy rate and numbers of pups per litter). Finally, RNAseq analysis permitted us to identify dysregulated genes (
Lhcgr
,
Fshr
,
Runx1
) and pathways (Extra Cellular Matrix and Steroid Synthesis).
Conclusions
Our novel mouse model is a versatile tool to provide innovative insights into study the effects of
Cyp17
overexpression and hyperandrogenism in the ovary.
Journal Article
Loss of Fertility in the Absence of Progesterone Receptor Expression in Kisspeptin Neurons of Female Mice
by
Elias, Carol F.
,
Gal, Arnon
,
Fernandez-Valdivia, Rodrigo
in
17β-Estradiol
,
Analysis
,
Animal experimentation
2016
Ovarian steroids, estradiol and progesterone, play central roles in regulating female reproduction by acting as both positive and negative regulators of gonadotropin-releasing hormone (GnRH) secretion in the hypothalamus. Recent studies have identified kisspeptin neurons of the hypothalamus as the target of estrogenic regulation of GnRH secretion. In this study, we aimed to determine the significance of progesterone receptor (PGR) expression in the kisspeptin neurons. To this end, the Pgr gene was selectively ablated in mouse kisspeptin neurons and the reproductive consequence assessed. The hypothalamus of the Pgr deficient female mouse expressed kisspeptin, the pituitary released LH in response to GnRH stimulation, and the ovary ovulated when stimulated with gonadotropins. However, the mutant mouse gradually lost cyclicity, was unable to generate a LH surge in response to rising estradiol, and eventually became infertile. Taken together, these results indicate that the loss of PGR impairs kisspeptin secretory machinery and therefore that PGR plays a critical role in regulating kisspeptin secretion.
Journal Article
Label-free, multi-scale imaging of ex-vivo mouse brain using spatial light interference microscopy
2016
Brain connectivity spans over broad spatial scales, from nanometers to centimeters. In order to understand the brain at multi-scale, the neural network in wide-field has been visualized in detail by taking advantage of light microscopy. However, the process of staining or addition of fluorescent tags is commonly required, and the image contrast is insufficient for delineation of cytoarchitecture. To overcome this barrier, we use spatial light interference microscopy to investigate brain structure with high-resolution, sub-nanometer pathlength sensitivity without the use of exogenous contrast agents. Combining wide-field imaging and a mosaic algorithm developed in-house, we show the detailed architecture of cells and myelin, within coronal olfactory bulb and cortical sections, and from sagittal sections of the hippocampus and cerebellum. Our technique is well suited to identify laminar characteristics of fiber tract orientation within white matter, e.g. the corpus callosum. To further improve the macro-scale contrast of anatomical structures, and to better differentiate axons and dendrites from cell bodies, we mapped the tissue in terms of its scattering property. Based on our results, we anticipate that spatial light interference microscopy can potentially provide multiscale and multicontrast perspectives of gross and microscopic brain anatomy.
Journal Article
RiboTag Analysis of Actively Translated mRNAs in Sertoli and Leydig Cells In Vivo
2013
Male spermatogenesis is a complex biological process that is regulated by hormonal signals from the hypothalamus (GnRH), the pituitary gonadotropins (LH and FSH) and the testis (androgens, inhibin). The two key somatic cell types of the testis, Leydig and Sertoli cells, respond to gonadotropins and androgens and regulate the development and maturation of fertilization competent spermatozoa. Although progress has been made in the identification of specific transcripts that are translated in Sertoli and Leydig cells and their response to hormones, efforts to expand these studies have been restricted by technical hurdles. In order to address this problem we have applied an in vivo ribosome tagging strategy (RiboTag) that allows a detailed and physiologically relevant characterization of the \"translatome\" (polysome-associated mRNAs) of Leydig or Sertoli cells in vivo. Our analysis identified all previously characterized Leydig and Sertoli cell-specific markers and identified in a comprehensive manner novel markers of Leydig and Sertoli cells; the translational response of these two cell types to gonadotropins or testosterone was also investigated. Modulation of a small subset of Sertoli cell genes occurred after FSH and testosterone stimulation. However, Leydig cells responded robustly to gonadotropin deprivation and LH restoration with acute changes in polysome-associated mRNAs. These studies identified the transcription factors that are induced by LH stimulation, uncovered novel potential regulators of LH signaling and steroidogenesis, and demonstrate the effects of LH on the translational machinery in vivo in the Leydig cell.
Journal Article