In mice, assisted reproductive technologies (ARTs) applied during gametogenesis and preimplantation development can result in disruption of genomic imprinting. In humans, these technologies and/or subfertility have been linked to perturbations in genomic imprinting. To understand how ARTs and infertility affect DNA methylation, it is important to understand DNA methylation dynamics and the role of regulatory factors at these critical stages. Recent genome studies performed using mouse and human gametes and preimplantation embryos have shed light onto these processes. Here, we comprehensively review the current state of knowledge regarding global and imprinted DNA methylation programming in the mouse and human. Available data highlight striking similarities in mouse and human DNA methylation dynamics during gamete and preimplantation development. Just as fascinating, these studies have revealed sex-, gene-, and allele-specific differences in DNA methylation programming, warranting future investigation to untangle the complex regulation of DNA methylation dynamics during gamete and preimplantation development.

Endometriosis is a highly prevalent, chronic, heterogeneous, fibro-inflammatory disease that remains recalcitrant to conventional therapy. We previously showed that loss of KLF11, a transcription factor implicated in uterine disease, results in progression of endometriosis. Despite extensive homology, co-expression, and human disease association, loss of the paralog Klf10 causes a unique inflammatory, cystic endometriosis phenotype in contrast to fibrotic progression seen with loss of Klf11. We identify here for the first time a novel role for KLF10 in endometriosis. In an animal endometriosis model, unlike wild-type controls, Klf10^−/− animals developed cystic lesions with massive immune infiltrate and minimal peri-lesional fibrosis. The Klf10^−/− disease progression phenotype also contrasted with prolific fibrosis and minimal immune cell infiltration seen in Klf11^−/− animals. We further found that lesion genotype rather than that of the host determined each unique disease progression phenotype. Mechanistically, KLF10 regulated CD40/CD154-mediated immune pathways. Both inflammatory as well as fibrotic phenotypes are the commonest clinical manifestations in chronic fibro-inflammatory diseases such as endometriosis. The complementary, paralogous Klf10 and Klf11 models therefore offer novel insights into the mechanisms of inflammation and fibrosis in a disease-relevant context. Our data suggests that divergence in underlying gene dysregulation critically determines disease-phenotype predominance rather than the conventional paradigm of inflammation being precedent to fibrotic scarring. Heterogeneity in clinical progression and treatment response are thus likely from disparate gene regulation profiles. Characterization of disease phenotype-associated gene dysregulation offers novel approaches for developing targeted, individualized therapy for recurrent and recalcitrant chronic disease.

Coumestrol (Cou) is a plant-derived phytoestrogen that induces various pathologies in the female reproductive tract. Although effects of phytoestrogens on reproductive function in other species are well documented, their influence on progesterone (P₄) and prostaglandin (PG) secretion in the mare is unknown. The aim of this study was to determine if Cou directly affects P₄ and PG concentrations (in vivo) and endometrial PG secretion (in vitro) in the mare. In experiment 1, the mares (n = 4) were fed for 14 days on a diet containing increasing proportions of alfalfa pellets (250 g–1 kg/day). An additional 4 mares were fed a standard diet (control group). Sequential blood samples were obtained for 8 h after feeding on Days 13 and 14 (1 kg/day alfalfa pellets). Feeding the mares alfalfa pellets up-regulated PGE₂ and 13,14-dihydro-15-ketoprostaglandin F_2alpha (PGFM) and down-regulated P₄ in the blood plasma compared to those in the control group (P < 0.05). In experiment 2, epithelial and stromal cells were exposed to E₂ (10⁻⁹ M) or Cou (10⁻⁸ M) for 24 h. In the in vitro study, Cou increased PG secretion in epithelial and stromal cells (P < 0.05). In both types of endometrial cells, Cou up-regulated PTGS-2 protein expression (P < 0.05). Moreover, PGES and PGFS proteins were up-regulated by Cou in epithelial cells (P < 0.01). These results indicate that Cou can disturb reproductive function by affecting reproductive hormone secretion and altering the endometrial milieu through PG stimulation. Coumestrol therefore may impair physiologic regulation of the estrous cycle and early pregnancy.

Although 90%–100% of mouse oocytes can be fertilized in vitro with capacitated spermatozoa within 1 h after insemination, oocytes within the oviduct are fertilized one by one over a period of several hours. In vitro experiments showed that both acrosome-intact and acrosome-reacted spermatozoa entered the cumulus oophorus, but that acrosome-reacted spermatozoa reached the surface of oocytes more readily than acrosome-intact spermatozoa. During the period of fertilization within the oviduct, acrosome-reacted spermatozoa were seen throughout the isthmus, but with higher incidence in the upper than in the mid- and lower segments of the isthmus. Very few spermatozoa were present in the ampulla, and almost all were acrosome reacted. Although the cumulus oophorus and zona pellucida are known to be able to induce or facilitate the acrosome reaction of spermatozoa, this picture makes it likely that almost all fertilizing mouse spermatozoa within the oviduct begin to react before ascending from the isthmus to the ampulla. We witnessed a reacted spermatozoon that stayed on the zona pellucida of a fertilized oocyte for a while; it then moved out of the cumulus before reaching the zona pellucida of the nearby unfertilized oocyte. We noted that only a few spermatozoa migrate from the isthmus to the ampulla during the progression of fertilization, and this must be one of the reasons why we do not see many spermatozoa swarming around a single oocyte during in vivo fertilization.

C-type natriuretic peptide (CNP) and its receptor natriuretic peptide receptor 2 (NPR2) play a paramount role in the maintenance of oocyte meiotic arrest in antral follicles via the regulation of the intra-oocyte levels of cyclic guanosine monophosphate and cyclic adenosine monophosphate. We investigated the potential of CNP 1) to maintain oocyte meiotic arrest during a prolonged prematuration culture and 2) to sustain acquisition of developmental competence of immature cumulus-oocyte complexes (COCs). Compact COCs were collected from small antral follicles of prepubertal unprimed mice and placed in prematuration culture under different CNP-supplemented media conditions. A preliminary analysis showed a dose-dependent effect of CNP on the maintenance of meiotic arrest. A dose of 25 nM maintained oocytes under meiotic arrest for 24 h, and this period was extended to 48 h in the presence of estradiol. Analysis of transzonal projections of COCs cultured with CNP indicated that oocyte-cumulus connections were well preserved after the prolonged prematuration culture. Furthermore, CNP medium supplemented with FSH and GDF9 promoted oocyte growth and induced a shift in oocyte chromatin configuration from a predominantly dispersed to a condensed configuration. Following in vitro maturation, oocytes cultured under CNP were capable of extruding the first polar body at a high rate (around 80%). Blastocyst formation was significantly improved when oocytes were cultured under CNP-supplemented medium containing FSH and GDF9. This study reports for the first time a prolonged prematuration culture system, with CNP as the pivotal factor, that can efficiently maintain oocytes retrieved from unprimed prepubertal mice under meiotic arrest while promoting their acquisition of developmental competence.

Fully grown oocytes of most vertebrates are arrested at prophase I of meiosis (G2 arrest). Upon exposure to steroid hormones, oocytes resume meiotic process, also called G2/M transition. The G protein-signaling pathway has been shown to play essential roles in the meiotic arrest at G2 phase. Previously, we showed that long chain fatty acyl-coenzyme A synthetase acsl1b was required for maintaining the meiotic arrest in Xenopus Acsl1b presumably synthesizes palmitoyl-coenzyme A that can be utilized by acyltransferases to modify proteins essential for the G2 arrest. In the present study, we report that protein acyltransferase ZDHHC3 functions downstream of acsl1b to maintain oocyte meiotic arrest. Depletion of maternal ZDHHC3 RNA in oocytes reduces the progesterone threshold to promote G2/M transition from 2 to 0.01 μM. As expected, G_s alpha palmitoylation level is greatly decreased in ZDHHC3-depleted oocytes. Furthermore, we mapped ZDHHC3 palmitoylation sites in G_s alpha and showed that palmitoylation-deficient G_s alpha failed to arrest oocytes at G2. We also identified a critical residue in ZDHHC3 critically required for its palmitoylation activity toward G_s alpha. Taken together, ZDHHC3 is a key acyltransferase to palmitoylate proteins in order to maintain G2 arrest in Xenopus oocytes.

Establishment of pregnancy requires interaction between the developing conceptus and the uterine mucosal immune system. Myeloid lineage cells (macrophages and dendritic cells) are key mediators of pregnancy in rodents and humans but relatively little is known regarding their role and distribution during early pregnancy in ruminants. We tested the hypothesis that myeloid lineage cell number, distribution, and function are altered during early pregnancy in dairy heifers. Dairy heifers were inseminated using sperm from a single bull (Day 0), and uteri and blood were collected at slaughter on Days 17 and 20 of pregnancy to investigate the response of myeloid lineage cells to the presence of a conceptus. Responses were compared to noninseminated heifers on Day 17 of the estrous cycle. Peripheral blood and uterine-derived immune cells were isolated magnetically and examined using flow cytometry. Immunohistochemical analysis was used to evaluate the spatial distribution of myeloid lineage cells in the endometrium and quantitative polymerase chain reaction was conducted to quantify abundance of mRNA transcripts associated with myeloid lineage cell function. Transcripts for major histocompatibility complex (MHC) II, cluster of differentiation (CD) 80, CD86, CD163, and indoleamine 2,3-dioxygenase (IDO) 1 were greater in endometrium of pregnant compared to cyclic heifers. Immunofluorescence analysis revealed increased labeling for MHCII and SIRPA in pregnant compared to cyclic heifers. There were approximately 50% more CD14 CD11c cells in the peripheral circulation of pregnant compared to cyclic heifers. A greater number of myeloid lineage cells were observed during early pregnancy, and this increase was most pronounced in and around the shallow glands. Furthermore, expression of molecules associated with a tolerogenic or alternatively activated phenotype of these cells also increased in pregnant heifers. The results support the hypothesis that myeloid lineage cells with a tolerogenic phenotype are involved in establishment of pregnancy in dairy heifers.

Bobby sox homolog (Bbx) is an evolutionally conserved gene, but its biological function remains elusive. Here, we characterized defects of Bbx mutant rats that were created by PiggyBac-mediated insertional mutagenesis. Smaller body size and male infertility were the two major phenotypes of homozygous Bbx mutants. Bbx expression profile analysis showed that Bbx was more highly expressed in the testis and pituitary gland than in other organs. Histology and hormonal gene expression analysis of control and Bbx-null pituitary glands showed that loss of Bbx appeared to be dispensable for pituitary histogenesis and the expression of major hormones. BBX was localized in the nuclei of postmeiotic spermatids and Sertoli cells in wild-type testes, but absent in mutant testes. An increased presence of aberrant multinuclear giant cells and apoptotic cells was observed in mutant seminiferous tubules. TUNEL-positive cells costained with CREM (round spermatid marker), but not PLZF (spermatogonia marker), gammaH2Ax (meiotic spermatocyte marker), or GATA4 (Sertoli cell marker). Finally, there were drastically reduced numbers and motility of epididymal sperm from Bbx-null rats. These results suggest that loss of BBX induces apoptosis of postmeiotic spermatids and results in spermiogenesis defects and infertility.

Incompatibilities in interspecific hybrids, such as reduced hybrid fertility and lethality, are common features resulting from reproductive isolation that lead to speciation. Subspecies crosses of house mice produce offspring in which one sex is infertile or absent, yet the molecular mechanisms of hybrid sterility are poorly understood. In this study, we observed extensive asynapsis of chromosomes and disturbance of the sex body in pachytene spermatocytes of sterile F1 males (PWK/Ph female × C57BL/6J male). We report the high-confidence identification of 4005 proteins in the pachytene spermatocytes of fertile F1 males (PWK/Ph male × C57BL/6J female) and sterile F1 males (PWK/Ph female × C57BL/6J male), of which 215 were upregulated and 381 were downregulated. Bioinformatics analysis of the proteome led to the identification of 43 and 59 proteins known to be essential for male meiosis and spermatogenesis in mice, respectively. Characterization of the proteome of pachytene spermatocytes associated with hybrid male sterility provides an inventory of proteins that is useful for understanding meiosis and the mechanisms of hybrid male infertility.

Normal development of ovarian follicles is critical for female reproduction and endocrine function. We have identified retinoic acid (RA) and the RA-degrading enzyme CYP26B1 as regulators of ovarian follicle development and showed that RA and a CYP26 inhibitor stimulated ovarian granulosa cell proliferation. The mechanism underpinning RA-dependent proliferation, however, is not known. The current study was designed to examine the role of intracellular calcium (Ca² ) signaling in mediating the effects of RA on primary mouse granulosa cell proliferation. In single-cell Ca² imaging experiments, treatment of cultured granulosa cells with RA increased the steady-state Ca² content of the endoplasmic reticulum (ER) stores. This correlated with increased store-operated Ca² entry (SOCE) and enhanced inositol 1,4,5-trisphosphate receptor (IP₃R)-dependent Ca² release. In proliferation assays, RA treatment or Cyp26b1 knockdown stimulated proliferation, whereas Cyp26b1 overexpression inhibited proliferation. When RA was given together with 2-aminoethoxydiphenylborane (2-APB), a blocker of IP₃R-dependent ER Ca² release and SOCE, with xestospongin C, a selective IP₃R- receptor antagonist, or with 3,5-bis (trifluoromethyl)pyrazole (BTP-2), a specific SOCE blocker, the stimulatory effect of RA on cell proliferation was abolished. Further investigation showed that treatment with 2-APB or BTP-2 inhibited RA induction of RA response element (RARE) activation in granulosa cells, confirming an important role for Ca² signaling in mediating RA actions. Overall, these data support a model in which RA regulates ovarian follicle development by stimulating granulosa cell proliferation and that this stimulatory effect is at least in part driven by the modulation of Ca² signaling.

Maternal obesity increases the risk of abnormal fetal growth, but the underlying mechanisms remain unclear. Because steroid hormones regulate fetal growth, and both pregnancy and obesity markedly alter circadian biology, we hypothesized that maternal obesity disrupts the normal rhythmic profiles of steroid hormones in rat pregnancy. Obesity was established by cafeteria (CAF) feeding for 8 wk prior to mating and throughout pregnancy. Control (CON) animals had ad libitum access to chow. Daily profiles of plasma corticosterone, 11-dehydrocorticosterone, progesterone, and testosterone were measured at Days 15 and 21 of gestation (term = 23 days) in maternal (both days) and fetal (Day 21) plasma. CAF mothers exhibited increased adiposity relative to CON and showed fetal and placental growth restriction. There was no change, however, in total fetal or placental mass due to slightly larger litter sizes in CAF. Nocturnal declines in progesterone were observed in maternal (39% lower) and fetal (45% lower) plasma in CON animals, but these were absent in CAF animals. CAF mothers were hyperlipidemic at both days of gestation, but this effect was isolated to the dark period at Day 21. CAF maternal testosterone was slightly lower at Day 15 (8%) but increased above CON by Day 21 (16%). Despite elevated maternal testosterone, male fetal testosterone was suppressed by obesity on Day 21. Neither maternal nor fetal glucocorticoid profiles were affected by obesity. In conclusion, obesity disrupts rhythmic profiles of maternal and fetal progesterone, preventing the normal nocturnal decline. Obesity subtly changed testosterone profiles but did not alter maternal and fetal glucocorticoids.

Preeclampsia (PE), a pregnancy-specific disorder characterized by hypertension and proteinuria beginning after 20 wk of pregnancy, is a major cause of maternal and fetal morbidity and mortality. Delivery of the placenta reverses the immediate clinical manifestations and remains the only reliable treatment for PE. Up to now, the causes of PE are not entirely clear. Human cyclooxygenase 2 (COX2, encoded by PTGS2) is a highly inducible enzyme and regulates inflammation, differentiation, mitogenesis, and angiogenesis. COX2 deficiency affects all stages of early pregnancy and leads to various impairments. We hypothesized that COX2 had a role in the occurrence of PE and investigated its expression and function. We found that the expression of COX2 in decidual tissues of PE was significantly lower compared to that of the normal pregnancy. After decidualization stimulation with N6, 2′-O-dibutyryl-cAMP and medroxyprogesterone 17-acetate of human endometrial stromal cells, the expression of COX2, decidualization marker molecules prolactin (PRL) and insulinlike growth factor binding protein 1 (IGFBP1) increased significantly. This augmentation was time dependent relative to decidualization. When PTGS2 was depleted, the decidualization was compromised, based on changes in morphology and in decidualization markers. We found that the mRNA and protein levels of vascular endothelial growth factor (VEGF) decreased markedly when PTGS2 was knocked down, providing a potential mechanism for decidual impairment. This was consistent with the decrease in mRNA and protein in decidual tissues of PE relative to normal tissues. Our results suggest that COX2 plays a vital role in human decidualization and that its decreased expression jeopardizes decidualization and vascularization of the endometrial stroma; it may be a significant factor in the occurrence of PE.

Successful pregnancy depends on well-regulated extravillous trophoblast (EVT) invasion into the uterine decidua and moderate uterine spiral artery remodeling. Ephrin receptor B4 (EPHB4) is a membrane-anchored receptor tyrosine kinase that plays an important role in various cellular functions in human normal tissue and tumors. Reportedly, EPHB4 plays important roles during placentation. Still, there is no investigation of EPHB4 modulating trophoblast function. In our study, term placentas of preeclamptic pregnancies showed a significantly increased EPHB4 expression compared to those of uncomplicated pregnancies (n = 15). Exogenous up-regulation of EPHB4 in HTR-8/SVneo cells was performed to investigate the effects of EPHB4 on cell biological behavior. The results showed that EPHB4 enhancement reduced cell proliferation and promoted trophoblast apoptosis; and inhibited cell migration, invasion, and endothelial replacement. Associated factors, such as matrix metalloproteinases, vascular endothelial growth factor, placental growth factor, and soluble Fms-like tyrosine kinase 1 were examined at transcriptional level. Furthermore, cell functional results were confirmed in a placenta-decidua coculture system, showing poor vascular remodeling. Additionally, we detected possible down-stream PI3K-Akt signal pathway involved in EPHB4-mediated function of HTR-8/SVneo cells. Our study demonstrates that EPHB4 overexpression may contribute to trophoblasts dysfunction and impair maternal artery remodeling, as is associated with the pathogenesis of preeclampsia.

In all mammalian species, critical events, including uterine receptivity and development of the conceptus (embryo/fetus and its associated extraembryonic membranes), must be intricately orchestrated and carefully timed during the window of implantation. Otherwise, failure of conceptuses to implant is inevitable, which accounts for 50%–75% of failures to establish pregnancy. Unlike human and rodent blastocysts, the blastocysts of pigs and ruminants undergo rapid transitions from spherical to tubular and filamentous conceptuses in response to histotroph during the peri-implantation period of pregnancy. Both arginine and secreted phosphoprotein 1 (SPP1; also known as osteopontin) are multifunctional molecules that increase significantly in ovine uterine histotroph during early pregnancy; however, little is known about their relationship and synergistic effects on conceptus development. Therefore, we conducted in vitro experiments using our established ovine trophectoderm cell line (oTr1) isolated from Day 15 ovine conceptuses to determine their migratory and adhesive responses to individual and combined effects of arginine and recombinant SPP1 (rSPP1) that contains an Arg-Gly-Asp (RGD) binding sequence. Migration and adhesion of oTr1 cells were significantly stimulated by rSPP1, whereas arginine alone only induced a significant increase in cell migration. However, the combination of arginine and rSPP1 had an additive effect on migration, and a synergistic effect on adhesion of oTr1 cells. Those cooperative effects of arginine and SPP1 were mediated by focal adhesion assembly-MTORC2-cytoskeletal reorganization and MAPK pathways. Collectively, results suggest that arginine and SPP1 in histotroph affect cellular events required for rapid elongation of ovine conceptuses during the peri-implantation period of pregnancy.

Uterine labor requires the conversion of a quiescent (propregnancy) uterus into an activated (prolabor) uterus, with increased sensitivity to endogenous uterotonic molecules. This activation is induced by stressors, particularly inflammation in term and preterm labor. Neuromedin U (NmU) is a neuropeptide known for its uterocontractile effects in rodents. The objective of the study was to assess the expression and function of neuromedin U receptor 2 (NmU-R2) and its ligands NmU and the more potent neuromedin S (NmS) in gestational tissues, and the possible implication of inflammatory stressors in triggering this system. Our data show that NmU and NmS are uterotonic ex vivo in murine tissue, and they dose-dependently trigger labor by acting specifically via NmU-R2. Expression of NmU-R2, NmU, and NmS is detected in murine and human gestational tissues by immunoblot, and the expression of NmS in placenta and of NmU-R2 in uterus increases considerably with gestation age and labor, which is associated with amplified NmU-induced uterocontractile response in mice. NmU- and NmS-induced contraction is associated with increased NmU-R2-coupled Ca transients, and Akt and Erk activation in murine primary myometrial smooth muscle cells (mSMCs), which are potentiated with gestational age. NmU-R2 is upregulated in vitro in mSMCs and in vivo in uterus in response to proinflammatory interleukin 1beta (IL1beta), which is associated with increased NmU-induced uterocontractile response and Ca transients in murine and human mSMCs; additionally, placental NmS is markedly upregulated in vivo in response to IL1beta. In human placenta at term, immunohistological analysis revealed NmS expression primarily in cytotrophoblasts; furthermore, stimulation with lipopolysaccharide (LPS; Gram-negative endotoxin) markedly upregulates NmS expression in primary human cytotrophoblasts isolated from term placentas. Correspondingly, decidua of women with clinical signs of infection who delivered preterm display significantly higher expression of NmS compared with those without infection. Importantly, in vivo knockdown of NmU-R2 prevents LPS-triggered preterm birth in mice and the associated neonatal mortality. Altogether, our data suggest a critical role for NmU-R2 and its ligands NmU and NmS in preterm labor triggered by infection. We hereby identify NmU-R2 as a relevant target for preterm birth.

Stallion-to-stallion variability in the quality of cryopreserved ejaculates postthaw affects the commercial acceptability of frozen semen and thus is a major constraint for the equine industry. In recent years, the molecular mechanisms associated with sperm damage during cryopreservation have become better understood. Identification of the freezability of the ejaculates before the freezing process is initiated will have a major impact on the equine industry. We studied three markers of oxidative stress in sperm, including 8-iso-PGF2alpha, 8-OH guanosine, and 4-hydroxynonenal (4-HNE); the presence of active caspase 3; and their changes after sperm cryopreservation. Although 4-HNE levels increased after cryopreservation (from 7% to 33%, P < 0.001), 8OH-guanosine and 8-ISO-PGF2alpha levels decreased after cryopreservation (from 130 to 35 arbitrary fluorescence units, P < 0.01, and from 1280 to 1233, P < 0.01, respectively). Postthaw sperm quality was classified as poor, average, or good using the 25th and 75th percentiles of all assays of sperm quality studied (motility, velocity, membrane functionality, and thiol content) as thresholds. Using these values, a sperm postthaw quality index was proposed. Receiver operating characteristic curves and the Youden J statistic were used to investigate the value of the measured parameters in fresh sperm as predictors of potential freezability. Using these techniques, we identified markers of bad freezers (percentages of caspase 3-positive dead sperm [area under the curve (AUC) = 0.820, P < 0.05] and percentages of caspase 3- and 4-HNE-positive sperm [AUC = 0.872, P < 0.05]) and good freezers (percentages of caspase 3-negative live sperm [AUC = 0.815, P < 0.05], percentages of live sperm with high thiol content [AUC = 0.907, P < 0.01], and percentages of 8-ISO-PGF2alpha-positive sperm [AUC = 0.900, P < 0.01]. Moreover, we described for the first time the presence of 8-ISO-PGF2alpha in stallion spermatozoa and revealed the importance of considering different markers of oxidative stress.

Although in vitro fertilization (IVF), one of the most effective and successful assisted reproductive technologies, is widely used for treating infertility and in animal breeding, increasing evidence indicates that IVF offspring are linked to various short- or long-term consequences. Erroneous epigenetic modifications induced by IVF are suspected of contributing to these consequences. Among these epigenetic modifications, microRNAs may affect embryo implantation and early postimplantation development. Here, we performed comparative microRNA profiling between in vivo-fertilized (IVO group) and in vitro-fertilized (IVF group) mouse embryos at Embryonic Day 3.5 (E3.5) and E7.5. Our dynamic analyses showed that the dysregulated microRNAs were mainly associated with the regulation of genes involved in carcinogenesis, genetic information processing, glucose metabolism, cytoskeleton organization, and neurogenesis. Further analysis showed that miR-199a-5p was consistently downregulated in IVF embryos compared with their IVO counterparts. Through gain- and loss-of-function experiments, we demonstrated that IVF-induced downregulation of miR-199a-5p results in a higher glycolytic rate and lower developmental potential of IVF blastocysts, including cell lineage misallocation and lower fetal survival post implantation. Therefore, preventing downregulation of miR-199a-5p may become an effective strategy for improving the development of IVF peri-implantation embryos in the future.

Melatonin exerts a range of physiological effects. However, the functional significance of melatonin in spermatogenesis and the underlying mechanisms remain unclear. MicroRNAs (miRNAs) are essential in the initiation and progression of testicular development, including spermatogenesis. Thus far, limited information is known about the role of miRNAs in melatonin-mediated spermatogenesis. In this study, the expression levels of testicular miRNA machinery genes, namely, Dgcr8 and Xpo5, were significantly increased by melatonin. The miRNA expression profile was identified in the testes of melatonin-treated mice. Ten miRNAs were significantly up-regulated, and 15 miRNAs were down-regulated. Melatonin (25 μM) enhanced cell growth and reduced apoptosis in GC-1 spg cells. Among the down-regulated miRNAs, miR-16 expression was influenced by melatonin in GC-1 spg cells. The miR-16 mimics in GC-1 spg cells significantly suppressed cell growth and promoted cell apoptosis. Conversely, transfection of the miR-16 inhibitor significantly increased cell growth and decreased cell apoptosis. The protein expression level of CCND1 (Cyclin D1) in GC-1 spg cells was decreased by the miR-16 mimics and increased by knockdown of miR-16. Moreover, bioinformatics and reporter activity analyses showed that Ccnd1 was a potential target of miR-16. These results suggested that miR-16 may function as a novel regulator of testicular functions during melatonin stimulation by targeting Ccnd1.

Teratozoospermia is generally associated with clinical infertility. Despite numerous studies, the molecular mechanisms underlying male infertility are still poorly understood. In the present study, we demonstrated that deletion of Spata46, a gene encoding a novel protein of unknown function found in mouse testis, was responsible for male subfertility, and the cause of subfertility was characterized as abnormal sperm head shape and a failure of sperm-egg fusion. We also demonstrated that SPATA46 was expressed predominantly in condensed spermatids, with a highly specific localization restricted to the subacrosomal area; the protein is located at the nuclear membrane due to a transmembrane region in the N-terminus of the protein. At the subcellular level, SPATA46-deficient condensed spermatids displayed structural defects consisting of a discontinuous nuclear envelope and a cavity in the nucleus associated with an abnormal nuclear shape. Additionally, in vitro, we determined that the absence of SPATA46 led to accumulation of sperm around the perivitelline space of eggs, and the same phenomenon was also observed for natural sperm incubated with an anti-SPATA46 antibody, suggesting functional relevance of SPATA46 for sperm-egg fusion. Taken together, these results indicated that SPATA46 is a novel protein involved in reshaping of the sperm head and sperm-egg fusion.

Advanced paternal age is linked to complications in pregnancy and genetic diseases in offspring. Aging results in excess reactive oxygen species (ROS) and DNA damage in spermatozoa; this damage can be transmitted to progeny with detrimental consequences. Although there is a loss of antioxidants with aging, the impact on aging male germ cells of the complete absence of either catalase (CAT) or superoxide dismutase 1 (SOD1) has not been investigated. We used CAT-null (Cat^−/−) and SOD1-null (Sod^−/−) mice to determine whether loss of these antioxidants increases germ cell susceptibility to redox dysfunction with aging. Aging reduced fertility and the numbers of Sertoli and germ cells in all mice. Aged Sod^−/− mice displayed an increased loss of fertility compared to aged wild-type mice. Treatment with the pro-oxidant SIN-10 increased ROS in spermatocytes of aged wild-type and Sod^−/− mice, while aged Cat^−/− mice were able to neutralize this ROS. The antioxidant peroxiredoxin 1 (PRDX1) increased with age in wild-type and Cat^−/− mice but was consistently low in young and aged Sod^−/− mice. DNA damage and repair markers (γ-H2AX and 53BP1) were reduced with aging and lower in young Sod^−/− and Cat^−/− mice. Colocalization of γ-H2AX and 53BP1 suggested active repair in young wild-type mice but reduced in young Cat^−/− and in Sod^−/− mice and with age. Oxidative DNA damage (8-oxodG) increased in young Sod^−/− mice and with age in all mice. These studies show that aged Sod^−/− mice display severe redox dysfunction, while wild-type and Cat^−/− mice have compensatory mechanisms to partially alleviate oxidative stress and reduce age-related DNA damage in spermatozoa. Thus, SOD1 but not CAT is critical to the maintenance of germ cell quality with aging.

We previously reported the successful induction of complete spermatogenesis of mice in neonatal testis tissues cultured on agarose gel, with the culture medium supplemented with a bovine serum albumin product, AlbuMAX. This method, however, has not been examined for fetal testis tissues. In this report, we tested the culture method for fetal testes of the Acrosin (Acr)-Gfp transgenic mouse, whose testicular germ cells express GFP from the midmeiotic phase onward, using AlbuMAX-containing medium. The fetal testis, from 19.5 days postcoitum (dpc) back to 14.5 dpc, showed spermatogenic progression and produced haploid cells in culture. On the other hand, testes of 13.5 dpc or earlier did not show the meiotic sign of Acr-Gfp expression. Regardless of the fetal age, tissue masses enlarged during the culture period because of the elongation and thickening of the seminiferous tubules. This simple culture method could be a useful experimental system to investigate fetal testicular development and germ cell biology.

Trichloroethylene (TCE) is a common environmental pollutant associated with adverse reproductive outcomes in humans. TCE intoxication occurs primarily through its biotransformation to bioactive metabolites, including S-(1,2-dichlorovinyl)-l-cysteine (DCVC). TCE induces oxidative stress and inflammation in the liver and kidney. Although the placenta is capable of xenobiotic metabolism and oxidative stress and inflammation in placenta have been associated with adverse pregnancy outcomes, TCE toxicity in the placenta remains poorly understood. We determined the effects of DCVC by using the human extravillous trophoblast cell line HTR-8/SVneo. Exposure to 10 and 20 μM DCVC for 10 h increased reactive oxygen species (ROS) as measured by carboxydichlorofluorescein fluorescence. Moreover, 10 and 20 μM DCVC increased mRNA expression and release of interleukin-6 (IL-6) after 24-h exposure, and these responses were inhibited by the cysteine conjugate beta-lyase inhibitor aminooxyacetic acid and by treatments with antioxidants (alpha-tocopherol and deferoxamine), suggesting that DCVC-stimulated IL-6 release in HTR-8/SVneo cells is dependent on beta-lyase metabolic activation and increased generation of ROS. HTR-8/SVneo cells exhibited decreased mitochondrial membrane potential at 5, 10, and 20 μM DCVC at 5, 10, and 24 h, showing that DCVC induces mitochondrial dysfunction in HTR-8/Svneo cells. The present study demonstrates that DCVC stimulated ROS generation in the human placental cell line HTR-8/SVneo and provides new evidence of mechanistic linkage between DCVC-stimulated ROS and increase in proinflammatory cytokine IL-6. Because abnormal activation of cytokines can disrupt trophoblast functions necessary for placental development and successful pregnancy, follow-up investigations relating these findings to physiologic outcomes are warranted.