Cyclin D2 is an FSH-responsive gene involved in gonadal cell proliferation and oncogenesis

Mitochondrial Protein Turnover Is Critical for Granulosa Cell Proliferation and Differentiation in Antral Follicles

Granulosa cell (GC) proliferation is essential for follicular development. FSH is a key factor in GC proliferation, and a continuous supply of high levels of ATP is necessary for cell proliferation. However, genes encoding proteins of the glycolytic pathways are poorly expressed in GCs. Therefore, we hypothesized that mitochondrial gene expression and protein synthesis play a primary role in ATP production during GC proliferation. To test this hypothesis, we performed an in vivo study of GCs collected from 23-day-old mice ovaries with or without equine chorionic gonadotropin (eCG) priming. It was observed that mitochondrial activity with membrane potential, expression of protein-coding genes (Nd1-6, Cytb, Atpase6,8) and transcription-related genes (Polrmt, Tfam, Tfb2m), copy number of mitochondrial (mt-)DNA, and protein synthesis were increased in GCs after 24 hours of eCG injection and mostly maintained elevated up to 48 hours. Therefore, we performed in vitro culture of GCs in DMEM medium supplemented with FSH, testosterone, and serum and containing different glucose concentrations with or without d-chloramphenicol (CRP) for 24 hours. GC proliferation and ATP production were observed to be independent of glucose concentration. Furthermore, FSH-induced mitochondrial activity with membrane potential, ATP content, BrdU-incorporated cell proliferation, intensity of mt-ND1 and mt-ND6 proteins, and expressions of marker genes for proliferation and differentiation were significantly decreased by CRP treatment. These results revealed the crucial role of mitochondria in the supply of ATP and the necessity of mitochondrial gene expression and protein synthesis in not only the proliferation but also the differentiation of GCs during follicular development.

Testicular transcriptional signatures associated with high fertility

Factors of high fertility are poorly described. The majority of transgenic or knockout models with a reproductive phenotype are subfertile or infertile phenotypes. Few genotypes have been linked to improved reproductive performance (0.2%) or increased litter size (1%). In this study, we used a unique mouse model, fertility line FL1, selected for 'high fertility' for more than 170 generations. This strain has almost doubled the number of littermates as well as their total birth weight accompanied by an elevated ovulation rate and increased numbers of corpora lutea compared to a randomly mated and unselected control line (Ctrl). Here, we investigate whether the gonadal tissue of FL1 males are affected by 'co-evolution' after more than 40 years of female-focused selection. Using microarrays, we analysed the testicular transcriptome of the FL1 and Ctrl mice. These data were also compared with previously published female gonadal transcriptional alterations. We detected alterations in testicular gene expression, which are partly associated with female reproductive performance. Thus, female-focused selection for litter size has not only affected the female side, but also has been manifested in transcriptional alterations on the male gonadal organ. This suggests consequences for the entire mouse lines in the long run and emphasizes the perspective of inevitably considering both genders about mechanisms of high fertility.

Gut microbiome disruption altered the biotransformation and liver toxicity of arsenic in mice

The mammalian gut microbiome (GM) plays a critical role in xenobiotic biotransformation and can profoundly affect the toxic effects of xenobiotics. Previous in vitro studies have demonstrated that gut bacteria have the capability to metabolize arsenic (As); however, the specific roles of the gut microbiota in As metabolism in vivo and the toxic effects of As are largely unknown. Here, we administered sodium arsenite to conventionally raised mice (with normal microbiomes) and GM-disrupted mice with antibiotics to investigate the role of the gut microbiota in As biotransformation and its toxicity. We found that the urinary total As levels of GM-disrupted mice were much higher, but the fecal total As levels were lower, than the levels in the conventionally raised mice. In vitro experiments, in which the GM was incubated with As, also demonstrated that the gut bacteria could adsorb or take up As and thus reduce the free As levels in the culture medium. With the disruption of the gut microbiota, arsenic biotransformation was significantly perturbed. Of note, the urinary monomethylarsonic acid/dimethylarsinic acid ratio, a biomarker of arsenic metabolism and toxicity, was markedly increased. Meanwhile, the expression of genes of one-carbon metabolism, including folr2, bhmt, and mthfr, was downregulated, and the liver S-adenosylmethionine (SAM) levels were significantly decreased in the As-treated GM-disrupted mice only. Moreover, As exposure altered the expression of genes of the p53 signaling pathway, and the expression of multiple genes associated with hepatocellular carcinoma (HCC) was also changed in the As-treated GM-disrupted mice only. Collectively, disruption of the GM enhances the effect of As on one-carbon metabolism, which could in turn affect As biotransformation. GM disruption also increases the toxic effects of As and may increase the risk of As-induced HCC in mice.

Schizophrenia-related cognitive dysfunction in the Cyclin-D2 knockout mouse model of ventral hippocampal hyperactivity

Elevated activity at the output stage of the anterior hippocampus has been described as a physiological endophenotype of schizophrenia, and its development maps onto the transition from the prodromal to the psychotic state. Interventions that halt the spreading glutamatergic over-activity in this region and thereby the development of overt schizophrenia could be promising therapies. However, animal models with high construct validity to support such pre-clinical development are scarce. The Cyclin-D2 knockout (CD2-KO) mouse model shows a hippocampal parvalbumin-interneuron dysfunction, and its pattern of hippocampal over-activity shares similarities with that seen in prodromal patients. Conducting a comprehensive phenotyping of CD2-KO mice, we found that they displayed novelty-induced hyperlocomotion (a rodent correlate of positive symptoms of schizophrenia), that was largely resistant against D1- and D2-dopamine-receptor antagonism, but responsive to the mGluR2/3-agonist LY379268. In the negative symptom domain, CD2-KO mice showed transiently reduced sucrose-preference (anhedonia), but enhanced interaction with novel mice and objects, as well as normal nest building and incentive motivation. Also, unconditioned anxiety, perseveration, and motor-impulsivity were unaltered. However, in the cognitive domain, CD2-knockouts showed reduced executive function in assays of rule-shift and rule-reversal learning, and also an impairment in working memory, that was resistant against LY379268-treatment. In contrast, sustained attention and forms of spatial and object-related memory that are mediated by short-term habituation of stimulus-specific attention were intact. Our results suggest that CD2-KO mice are a valuable model in translational research targeted at the pharmacoresistant cognitive symptom domain in causal relation to hippocampal over-activity in the prodrome-to-psychosis transition.

Lack of cyclin D3 induces skeletal muscle fiber-type shifting, increased endurance performance and hypermetabolism

The mitogen-induced D-type cyclins (D1, D2 and D3) are regulatory subunits of the cyclin-dependent kinases CDK4 and CDK6 that drive progression through the G1 phase of the cell cycle. In skeletal muscle, cyclin D3 plays a unique function in controlling the proliferation/differentiation balance of myogenic progenitor cells. Here, we show that cyclin D3 also performs a novel function, regulating muscle fiber type-specific gene expression. Mice lacking cyclin D3 display an increased number of myofibers with higher oxidative capacity in fast-twitch muscle groups, primarily composed of myofibers that utilize glycolytic metabolism. The remodeling of myofibers toward a slower, more oxidative phenotype is accompanied by enhanced running endurance and increased energy expenditure and fatty acid oxidation. In addition, gene expression profiling of cyclin D3-/- muscle reveals the upregulation of genes encoding proteins involved in the regulation of contractile function and metabolic markers specifically expressed in slow-twitch and fast-oxidative myofibers, many of which are targets of MEF2 and/or NFAT transcription factors. Furthermore, cyclin D3 can repress the calcineurin- or MEF2-dependent activation of a slow fiber-specific promoter in cultured muscle cells. These data suggest that cyclin D3 regulates muscle fiber type phenotype, and consequently whole body metabolism, by antagonizing the activity of MEF2 and/or NFAT.

Expression pattern of new genes regulating female sex differentiation and in vitro maturational status of oocytes in pigs

The processes underlying maturation of mammalian oocytes are considered crucial for the oocytes ability to undergo monospermic fertilization. The same factors of influence are suggested to impact the development of sex associated characteristics, allowing sex differentiation to progress during embryonic growth. The primary aim of the study was to analyze the gene ontology groups involved in regulation of porcine oocytes' response to endogenous stimuli. The results obtained would indicate potential genes influencing sex differentiation. Additionally, they could help to determine new genetic markers, expression profile of which is substantially regulated during porcine oocytes' in vitro maturation. To achieve that, porcine oocytes were collected for analysis before and after in vitro maturation. Pigs were used as they are a readily available model that presents significant similarity to humans in terms of physiology and anatomy. Microarray analysis of oocytes, before and after in vitro maturation was performed and later validated by RT-qPCR. We have particularly detected and analyzed genes belonging to gene ontology groups associated with hormonal stimulation during maturation of the oocytes, that exhibited significant change in expression (fold change ≥ |2|; p < 0.05) namely "Female sex differentiation" (CCND2, MMP14, VEGFA, FST, INHBA, NR5A1), "Response to endogenous stimulus" (INSR, ESR1, CCND2, TXNIP, TACR3, MMP14, FOS, AR, EGR2, IGFBP7, TGFBR3, BTG2, PLD1, PHIP, UBE2B) and "Response to estrogen stimulus" (INSR, ESR1, CCND2, IHH, TXNIP, TACR3, MMP14). Some of them were characteristic for just one of the described ontologies, while some belonged into multiple ontological terms. The genes were analyzed, with their relation to the processes of interest explained. Overall, the study provides us with a range of genes that might serve as molecular markers of in vitro maturation associated processes of the oocytes. This knowledge might serve as a reference for further studies and, after further validation, as a potentially useful knowledge in assessment of the oocytes during assisted reproduction processes.

MicroRNA-376a regulates cell proliferation and apoptosis by targeting forkhead box protein P2 in lymphoma

The present study aimed to investigate microRNA-376a (miR-376a) expression in lymphoma, and to investigate the effect of miR-376a on cell proliferation and apoptosis at cytological and molecular levels. The expression of miR-376a in lymphoma issue and cells was detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR), the expression of forkhead box protein P2 (FOXP2) was detected by RT-qPCR and western blot analysis, and the effect of miR-376a on cell proliferation and apoptosis were studied by an MTT assay and flow cytometry, respectively. Additionally, the expression levels of cyclin D2, cyclin A, cyclin B, apoptosis-associated proteins B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) were detected by western blot analysis. Furthermore, the target of miR-376a was predicted and clarified using a dual-luciferase reporter assay. The expression of miR-376a was downregulated and FOXP2 was upregulated in lymphoma tissues and cells. miR-376a overexpression inhibited lymphoma cell proliferation and induced apoptosis by regulating the expression levels of cyclin D2, cyclin A, Bax and Bcl-2. The dual-luciferase reporter assay demonstrated that FOXP2 was a target of miR-376a. miR-376a overexpression induced apoptosis by targeting FOXP2. Overexpression of miR-376a inhibited cell proliferation and induced apoptosis by targeting FOXP2 in lymphoma. Therefore, miR-376a and FOXP2 have the potential for use as biomarkers of lymphoma.

The Strange Case of CDK4/6 Inhibitors: Mechanisms, Resistance, and Combination Strategies

CDK4/6 inhibitors have emerged as a powerful class of agents with clinical activity in a number of malignancies. Targeting the cell cycle represents a core attack on a defining feature of cancer. However, the mechanisms through which selective CDK4/6 targeted agents act has few parallels in the current pharmaceutical armamentarium against cancer. Notably, CDK4/6 inhibitors act downstream of most mitogenic signaling cascades, which have implications both related to clinical efficacy and resistance. Core knowledge of cell cycle processes has provided insights into mechanisms of intrinsic resistance to CDK4/6 inhibitors; however, the basis of acquired resistance versus durable response is only beginning to emerge. This review focuses on the mechanism of action and biomarkers to direct the precision use of CDK4/6 inhibitors and rationally-developed combination therapies.

Bone marrow derived mesenchymal stem cells transplantation rescues premature ovarian insufficiency induced by chemotherapy

Premature ovarian insufficiency (POI) is an important cause of infertility and also cause menopausal symptoms, which greatly reduced the quality of life for women. Hormone replacement therapy (HRT), as an important strategy, improved the quality of life for patients, however, the role of HRT in promoting fertility remains controversial. Therefore, seeking an optimal regime for POI becomes more urgent. In this study, we established POI model induced by CTX and BUS and utilized bone marrow derived mesenchymal stem cells (BM-MSCs) transplantation to treat the POI. We found that the decrease of estrogen and the increase of FSH induced by administration of CTX and BUS were rescued by BM-MSC transplantation. H&E staining and TUNEL assay showed that there were more healthy ovarian follicles and less apoptosis of ovarian cells after treatment with BM-MSCs. Further studies showed that there was an obvious decrease of Bax, p53, and p21 after transplantation, however, CyclinD2 was increased. In conclusion, our results demonstrated that BM-MSCs could restore injured ovarian function. Inhibiting apoptosis and promoting residual ovarian cell proliferation may contribute to the process.

Effects of an Environmentally Relevant Phthalate Mixture on Cultured Mouse Antral Follicles

Phthalates are used in building materials, medical devices, and personal care products. Most studies on phthalates have focused on single phthalates, but it is important to study mixtures of phthalates because humans are exposed to such mixtures daily. We tested the hypothesis that phthalate mixture exposure decreases antral follicle growth, compromises steroidogenic capacity, and induces atresia. Antral follicles from adult CD-1 mice were cultured with vehicle control or phthalate mixture (1-500 µg/ml) for 96 h. The mixture was made of 35% diethyl phthalate, 21% di(2-ethylhexyl) phthalate, 15% dibutyl phthalate, 15% diisononyl phthalate, 8% diisobutyl phthalate, and 5% benzylbutyl phthalate. During culture, antral follicle diameters were measured every 24 h to monitor growth. After culture, media were subjected to measurements of sex steroid hormones and follicles were subjected to evaluation of gene expression and atresia. The phthalate mixture (100 and 500 µg/ml) decreased antral follicle growth starting at 24 h compared to controls. The mixture at 10, 100, and 500 µg/ml also decreased androstenedione, testosterone, estrone, and estradiol levels compared to control. The mixture (10, 100, and 500 µg/ml) reduced atresia rating, but it induced more oocyte fragmentation compared to control. The phthalate mixture at different doses adversely affected cell cycle regulators, antioxidant enzymes, apoptotic factors, steroidogenic enzymes, and receptors. Collectively, these data indicate that exposure to an environmentally relevant phthalate mixture reduces antral follicle growth, induces oocyte fragmentation, and decreases hormone production by adversely affecting the expression of cell cycle regulators, apoptotic factors, steroidogenic enzymes, and receptors.

miR-124 represses the mesenchymal features and suppresses metastasis in Ewing sarcoma

Metastasis is the most powerful predictor of poor outcome of Ewing sarcoma (ES). Thus, identification of new molecules involved in tumor metastasis is of crucial importance to reduce morbidity and mortality of this devastating disease. In this study, we found that miR-124, a highly conserved miRNA, was suppressed in ES tissues and might be associated with tumor metastasis through suppressing its mesenchymal features. Overexpression of miR-124 suppressed the invasion of ES cells in vitro and tumor metastasis in vivo, which might be achieved through suppressing its mesenchymal features, as overexpression of miR-124 could repress the mesenchymal genes expression, and inhibit cell differentiation to mesenchymal lineages in ES cells. However, when SLUG was experimentally restored in these cells, mesenchymal features including suppressed expression of mesenchymal genes and decreased invasive ability were observed. We also found that cyclin D2 (CCND2) was a novel target gene of miR-124, and was directly involved in miR-124-mediated suppressive effects on cell growth. Lastly, we found that treatment with 5-Aza-CdR restored the expression of miR-124, accompanied with suppressed cell proliferation, invasion and mesenchymal features of ES cells, which demonstrated that hypermethylation might be involved in the regulation of miR-124 expression. Collectively, our data suggest that hypermethylation-mediated suppression of miR-124 might be involved in the tumor initiation and metastasis through suppressing the mesenchymal features of ES cells.

Berberine inhibits experimental varicocele-induced cell cycle arrest via regulating cyclin D1, cdk4 and p21 proteins expression in rat testicles

The aim of this study was to uncover the protective effect of berberine (BBR), an antioxidant chemical, on experimental varicocele (VCL)-induced adverse effects on cell cycle machinery during early germ cells mitosis. To follow-up this study, 30 mature male Wistar rats were divided into control-sham, nontreated VCL, 50 mg kg-1 and 100 mg kg-1 BBR-treated VCL groups. Following 60 days, histological alterations were analysed by haematoxylin and eosin (H and E) staining, and expressions of cyclin-D1, cyclin-dependent kinase-4 (cdk4) and p21 were investigated by immunohistochemical (IHC) staining technique. Finally, DNA ladder test was carried out to examine the testicular DNA fragmentation. Administration of BBR remarkably diminished the percentage of seminiferous tubules with deformed shape, depleted germ cells and germ cells dissociation compared to VCL-sole group. The IHC observations showed that BBR significantly (p < .05) reduced VCL-induced p21 expression increase and up-regulated cyclin-D1 and cdk4 expressions. Moreover, BBR decreased VCL-induced DNA fragmentation. In conclusion, BBR can promote cell cycle through cellular DNA content protection, p21 expression down-regulation and maintaining cyclin-D1 and cdk4 expressions. Thus, BBR could be considered as a novel protective biochemical agent against experimental VCL-induced derangements. However, more studies are needed to uncover BBR-induced effects on cells cycle process and germ cells development.

Hsa-miR-875-5p exerts tumor suppressor function through down-regulation of EGFR in colorectal carcinoma (CRC)

Hsa-miRNA-875-5p (miR-875-5p) has recently been discovered to have anticancer efficacy in different organs. However, the role of miR-875-5p on colorectal carcinoma (CRC) is still ambiguous. In this study, we investigated the role of miR-875-5p on the development of CRC. The results indicated that miR-875-5p was significantly down-regulated in primary tumor tissues and very low levels were found in CRC cell lines. Ectopic expression of miR-875-5p in CRC cell lines significantly suppressed cell growth as evidenced by cell viability assay, colony formation assay and BrdU staining, through inhibition of cyclin D1, cyclin D2, CDK4 and up-regulation of p57(Kip2) and p21(Waf1/Cip1). In addition, miR-875-5p induced apoptosis, as indicated by concomitantly with up-regulation of key apoptosis protein cleaved caspase-3, and down-regulation of anti-apoptosis protein Bcl2. Moreover, miR-875-5p inhibited cellular migration and invasiveness through inhibition of matrix metalloproteinases (MMP)-7 and MMP-9. Further, oncogene EGFR was revealed to be a putative target of miR-875-5p, which was inversely correlated with miR-875-5p expression in CRC. Taken together, our results demonstrated that miR-875-5p played a pivotal role on CRC through inhibiting cell proliferation, migration, invasion, and promoting apoptosis by targeting oncogenic EGFR.

Severely impaired adult brain neurogenesis in cyclin D2 knock-out mice produces very limited phenotypic changes

The discovery of new neurons being produced in the brains of adult mammals (adult brain neurogenesis) began a quest to determine the function(s) of these cells. Major hypotheses in the field have assumed that these neurons play pivotal role, in particular, in learning and memory phenomena, mood control, and epileptogenesis. In our studies summarized herein, we used cyclin D2 knockout (KO) mice, as we have shown that cyclin D2 is the key factor in adult brain neurogenesis and thus its lack produces profound impairment of the process. On the other hand, developmental neurogenesis responsible for the brain formation depends only slightly on cyclin D2, as the mutants display minor structural abnormalities, such as smaller hippocampus and more severe disturbances in the structure of the olfactory bulbs. Surprisingly, the studies have revealed that cyclin D2 KO mice did not show major deficits in several behavioral paradigms assessing hippocampal learning and memory. Furthermore, missing adult brain neurogenesis affected neither action of antidepressants, nor epileptogenesis. On the other hand, minor deficits observed in cyclin D2 KO mice in fine tuning of cognitive functions, species-typical behaviors and alcohol consumption might be explained by a reduced hippocampal size and/or other developmentally driven brain impairments observed in these mutant mice. In aggregate, surprisingly, missing almost entirely adult brain neurogenesis produces only very limited behavioral phenotype that could be attributed to the consequences of the development-dependent minor brain abnormalities.

Notch Signaling Regulates Differentiation and Steroidogenesis in Female Mouse Ovarian Granulosa Cells

The Notch pathway is a highly conserved juxtacrine signaling mechanism that is important for many cellular processes during development, including differentiation and proliferation. Although Notch is important during ovarian follicle formation and early development, its functions during the gonadotropin-dependent stages of follicle development are largely unexplored. We observed positive regulation of Notch activity and expression of Notch ligands and receptors following activation of the luteinizing hormone-receptor in prepubertal mouse ovary. JAG1, the most abundantly expressed Notch ligand in mouse ovary, revealed a striking shift in localization from oocytes to somatic cells following hormone stimulation. Using primary cultures of granulosa cells, we investigated the functions of Jag1 using small interfering RNA knockdown. The loss of JAG1 led to suppression of granulosa cell differentiation as marked by reduced expression of enzymes and factors involved in steroid biosynthesis, and in steroid secretion. Jag1 knockdown also resulted in enhanced cell proliferation. These phenotypes were replicated, although less robustly, following knockdown of the obligate canonical Notch transcription factor RBPJ. Intracellular signaling analysis revealed increased activation of the mitogenic phosphatidylinositol 3-kinase/protein kinase B and mitogen-activated protein kinase/extracellular signal-regulated kinase pathways following Notch knockdown, with a mitogen-activated protein kinase kinase inhibitor blocking the enhanced proliferation observed in Jag1 knockdown granulosa cells. Activation of YB-1, a known regulator of granulosa cell differentiation genes, was suppressed by Jag1 knockdown. Overall, this study reveals a role of Notch signaling in promoting the differentiation of preovulatory granulosa cells, adding to the diverse functions of Notch in the mammalian ovary.

Aberrant methylation of HTATIP2 and UCHL1 as a predictive biomarker for cholangiocarcinoma

Cholangiocarcinoma (CCA) is the most common primary liver cancer in Northeastern Thailand where liver fluke infection is highly endemic. Although aberrant DNA methylation in CCA has been reported by several investigators, little is known regarding the associations between them. In the present study, the results obtained from our previously published methylation array were analyzed and 10 candidate genes involved in DNA repair [protein phosphatase 4 catalytic subunit (PPP4C)], apoptosis [runt related transcription factor 3 (RUNX3), interferon regulatory factor 4 (IRF4), ubiquitin C‑terminal hydrolase L1 (UCHL1) and tumor protein p53 inducible protein 3 (TP53I3)], cell proliferation [cyclin D2 (CCND2) and Ras association domain family member 1 (RASSF1)], drug metabolism [aldehyde dehydrogenase 1 family member A3 (ALDH1A3) and solute carrier family 29 member 1 (SLC29A1)] and angiogenesis [human immunodeficiency virus‑1 tat interactive protein 2 (HTATIP2)] were selected for quantification of their methylation levels in 54 CCA and 19 adjacent normal tissues using methylation‑sensitive high‑resolution melting. The associations between the methylation status of the individual genes and clinical parameters were statistically analyzed. High methylation levels were observed in UCHL1, IRF4, CCND2, HTATIP2 and TP53I3. The median methylation level of UCHL1 was 57.3% (range, 3.15 to 88.7%) and HTATIP2 was 13.6% (range, 7.5 to 36.7%). By contrast, low methylation of HTATIP2 and UCHL1 was identified in adjacent normal tissues. The methylation status of HTATIP2 and UCHL1 was associated with patients' overall survival. CCA patients with high methylation of HTATIP2 and low methylation of UCHL1 exhibited longer overall survival. In addition, multivariate Cox regression analysis demonstrated that UCHL1 methylation was an independent factor for CCA with hazard ratio of 1.81 (95% confidence interval, 1.01‑3.25) in high methylation group. The combination of HTATIP2 and UCHL1 methylation status strongly supported their potential predictive biomarker in which patients with CCA who had high methylation of HTATIP2 and low methylation of UCHL1 showed longer overall survival than those with low HTATIP2 methylation and high UCHL1 methylation. In conclusion, the present study revealed the value of aberrant DNA methylation of HTATIP2 and UCHL1, which may serve as a potential predictive biomarker for CCA.

Cyclin D2 is a critical mediator of exercise-induced cardiac hypertrophy

A number of signaling pathways underlying pathological cardiac hypertrophy have been identified. However, few studies have probed the functional significance of these signaling pathways in the context of exercise or physiological pathways. Exercise studies were performed on females from six different genetic mouse models that have been shown to exhibit alterations in pathological cardiac adaptation and hypertrophy. These include mice expressing constitutively active glycogen synthase kinase-3β (GSK-3βS9A), an inhibitor of CaMK II (AC3-I), both GSK-3βS9A and AC3-I (GSK-3βS9A/AC3-I), constitutively active Akt (myrAkt), mice deficient in MAPK/ERK kinase kinase-1 (MEKK1-/-), and mice deficient in cyclin D2 (cyclin D2-/-). Voluntary wheel running performance was similar to NTG littermates for five of the mouse lines. Exercise induced significant cardiac growth in all mouse models except the cyclin D2-/- mice. Cardiac function was not impacted in the cyclin D2-/- mice and studies using a phospho-antibody array identified six proteins with increased phosphorylation (greater than 150%) and nine proteins with decreased phosphorylation (greater than 33% decrease) in the hearts of exercised cyclin D2-/- mice compared to exercised NTG littermate controls. Our results demonstrate that unlike the other hypertrophic signaling molecules tested here, cyclin D2 is an important regulator of both pathologic and physiological hypertrophy. Impact statement This research is relevant as the hypertrophic signaling pathways tested here have only been characterized for their role in pathological hypertrophy, and not in the context of exercise or physiological hypertrophy. By using the same transgenic mouse lines utilized in previous studies, our findings provide a novel and important understanding for the role of these signaling pathways in physiological hypertrophy. We found that alterations in the signaling pathways tested here had no impact on exercise performance. Exercise induced cardiac growth in all of the transgenic mice except for the mice deficient in cyclin D2. In the cyclin D2 null mice, cardiac function was not impacted even though the hypertrophic response was blunted and a number of signaling pathways are differentially regulated by exercise. These data provide the field with an understanding that cyclin D2 is a key mediator of physiological hypertrophy.

Selection for female traits of high fertility affects male reproductive performance and alters the testicular transcriptional profile

Background

Many genes important for reproductive performance are shared by both sexes. However, fecundity indices are primarily based on female parameters such as litter size. We examined a fertility mouse line (FL2), which has a considerably increased number of offspring and a total litter weight of 180% compared to a randomly bred control line (Ctrl) after more than 170 generations of breeding. In the present study, we investigated whether there might be a parallel evolution in males after more than 40 years of breeding in this outbred mouse model.

Results

Males of the fertility mouse line FL2 showed reduced sperm motility performance in a 5 h thermal stress experiment and reduced birth rate in the outbred mouse line. Transcriptional analysis of the FL2 testis showed the differential expression of genes associated with steroid metabolic processes (Cyp1b1, Cyp19a1, Hsd3b6, and Cyp21a1) and female fecundity (Gdf9), accompanied by 150% elevated serum progesterone levels in the FL2 males. Cluster analysis revealed the downregulation of genes of the kallikrein-related peptidases (KLK) cluster located on chromosome 7 in addition to alterations in gene expression with serine peptidase activity, e.g., angiotensinogen (Agt), of the renin-angiotensin system essential for ovulation. Although a majority of functional annotations map to female reproduction and ovulation, these genes are differentially expressed in FL2 testis.

Conclusions

These data indicate that selection for primary female traits of increased litter size not only affects sperm characteristics but also manifests as transcriptional alterations of the male side likely with direct long-term consequences for the reproductive performance of the mouse line.

Electronic supplementary material

The online version of this article (10.1186/s12864-017-4288-z) contains supplementary material, which is available to authorized users.

The Ciliary Margin Zone of the Mammalian Retina Generates Retinal Ganglion Cells

The retina of lower vertebrates grows continuously by integrating new neurons generated from progenitors in the ciliary margin zone (CMZ). Whether the mammalian CMZ provides the neural retina with retinal cells is controversial. Live imaging of embryonic retina expressing eGFP in the CMZ shows that cells migrate laterally from the CMZ to the neural retina where differentiated retinal ganglion cells (RGCs) reside. Because Cyclin D2, a cell-cycle regulator, is enriched in ventral CMZ, we analyzed Cyclin D2^-/- mice to test whether the CMZ is a source of retinal cells. Neurogenesis is diminished in Cyclin D2 mutants, leading to a reduction of RGCs in the ventral retina. In line with these findings, in the albino retina, the decreased production of ipsilateral RGCs is correlated with fewer Cyclin D2⁺ cells. Together, these results implicate the mammalian CMZ as a neurogenic site that produces RGCs and whose proper generation depends on Cyclin D2 activity.

Cyclin D3 deficiency inhibits skin tumor development, but does not affect normal keratinocyte proliferation

Rearrangement and amplification of the D-type cyclin genes have been reported in human cancer. Previous studies have demonstrated that Ras-mediated skin tumorigenesis depends on pathways that act through cyclin D1 and D2; however, the role of cyclin D3 remains unknown. The present study demonstrates that cyclin D3 ablation does not affect keratinocyte proliferation, but instead increases apoptosis levels in the bulge region of the hair follicle. Consequently, cyclin D3 ablation reduces skin papilloma development in a Ras-dependent carcinogenesis model. Previous results revealed that cyclin D3 preferentially binds to cyclin-dependent kinase 6 (CDK6) in mouse keratinocytes and transgenic expression of CDK6 (K5CDK6 mice) inhibits skin tumor development. Thus, we hypothesized that the inhibitory effect of CDK6 is dependent on cyclin D3 expression. To test this hypothesis, a mouse model that overexpresses CDK6 and does not express cyclin D3 (K5CDK6/cyclin D3-/− compound mouse) was developed. Biochemical analysis of the epidermis of K5CDK6/cyclin D3-/− mice revealed that cyclin D3 ablation resulted in increased expression of cyclin D1 protein, with a consequent elevation in the level of CDK6/cyclin D1 and CDK4/cyclin D1 complexes. These findings were concurrent with the increase skin papilloma malignant progression observed in K5CDK6/cyclin D3-/− mice. In summary the absence of cyclin D3 led to fewer number of papillomas in cyclin D3-ablated mice than in the wild-type owing to increased apoptosis, suggesting that alterations in cell survival are a crucial mechanism for crippling cellular defense against neoplasia. The results of the current study also suggest that although cyclin D3 expression does not alter the tumor suppressive role of CDK6 in skin carcinogenesis, the compensatory increase in cyclin D1 can shift the balance towards malignant progression.

How Protein Kinase A Activates Canonical Tyrosine Kinase Signaling Pathways To Promote Granulosa Cell Differentiation

Protein kinase A (PKA) has recently been shown to mimic the actions of follicle-stimulating hormone (FSH) by activating signaling pathways that promote granulosa cell (GC) differentiation, such as phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK). We sought to elucidate the mechanism by which PKA, a Ser/Thr kinase, intersected the PI3K/AKT and MAPK/ERK pathways that are canonically activated by receptor tyrosine kinases (RTKs). Our results show that for both of these pathways, the RTK is active in the absence of FSH yet signaling down the pathways to commence transcriptional responses requires FSH-stimulated PKA activation. For both pathways, PKA initiates signaling by regulating the activity of a protein phosphatase (PP). For the PI3K/AKT pathway, PKA activates the Ser/Thr PP1 complexed with the insulinlike growth factor 1 receptor (IGF-1R) and insulin receptor substrate 1 (IRS1) to dephosphorylate Ser residues on IRS1, authorizing phosphorylation of IRS1 by the IGF-1R to activate PI3K. Treatment of GCs with FSH and exogenous IGF-1 initiates synergistic IRS1 Tyr phosphorylation and resulting gene activation. The mechanism by which PKA activates PI3K is conserved in preovulatory GCs, MCF7 breast cancer cells, and FRTL thyroid cells. For the MAPK/ERK pathway, PKA promotes inactivation of the MAPK phosphatase (MKP) dual specificity phosphatase (DUSP) MKP3/DUSP6 to permit MEK-phosphorylated ERK to accumulate downstream of the epidermal growth factor receptor. Thus, for the two central signaling pathways that regulate gene expression in GCs, FSH via PKA intersects canonical RTK-regulated signaling by modulating the activity of PPs.

Chronic low-dose exposure to a mixture of environmental endocrine disruptors induces microRNAs/isomiRs deregulation in mouse concomitant with intratesticular estradiol reduction

Humans are environmentally exposed not only to single endocrine-disrupting chemicals (EDCs) but to mixtures that affect their reproductive health. In reproductive tissues, microRNAs (miRNAs) are emerging as key targets of EDCs. Here, we analysed changes in the testis "miRNome" (and their biogenesis mechanism) in chronically exposed adult mice to a cocktail of five EDCs containing 0.3 mg/kg-body weight (BW)/day of each phthalate (DEHP, DBP, BBP) and 0.05 mg/kg-BW/day of each alkylphenol (NP, OP), from conception to adulthood. The testis "miRNome" was characterised using next-generation sequencing (NGS). Expression levels of genes involved in miRNA biogenesis were measured by RT-qPCR, as well as several physiological and cytological parameters. We found two up-regulated, and eight down-regulated miRNAs and thirty-six differentially expressed isomiRs along with an over-expression of Drosha, Adar and Zcchc11. A significant decrease of intratesticular estradiol but not testosterone was detected. Functional analysis showed altered spermatogenesis, germ cell apoptosis and negative correlation of miR-18a-5p with Nr1h2 involved in the deregulation of the steroidogenesis pathway. Here, we present the first association between miRNA/isomiRs deregulation, their mechanisms of biogenesis and histopathological and hormonal alterations in testes of adult mice exposed to a mixture of low-dose EDCs, which can play a role in male infertility.

A novel action of follicle-stimulating hormone in the ovary promotes estradiol production without inducing excessive follicular growth before puberty

In cyclic females, FSH stimulates ovarian estradiol (E2) production and follicular growth up to the terminal stage. A transient elevation in circulating FSH and E2 levels occurs shortly after birth. But what could be the action of FSH on the ovary during this period, and in particular how it stimulates ovarian steroidogenesis without supporting terminal follicular maturation is intriguing. By experimentally manipulating FSH levels, we demonstrate in mice that the mid-infantile elevation in FSH is mandatory for E2 production by the immature ovary, but that it does not stimulate follicle growth. Importantly, FSH increases aromatase expression to stimulate E2 synthesis, however it becomes unable to induce cyclin D2, a major driver of granulosa cell proliferation. Besides, although FSH prematurely induces luteinizing hormone (LH) receptor expression in granulosa cells, LH pathway is not functional in these cells to induce their terminal differentiation. In line with these results, supplying infantile mice with a superovulation regimen exacerbates E2 production, but it does not stimulate the growth of follicles and it does not induce ovulation. Overall, our findings unveil a regulation whereby high postnatal FSH concentrations ensure the supply of E2 required for programming adult reproductive function without inducing follicular maturation before puberty.

G1 cyclins link proliferation, pluripotency and differentiation of embryonic stem cells

Progression of mammalian cells through the G1 and S phases of the cell cycle is driven by the D-type and E-type cyclins. According to the current models, at least one of these cyclin families must be present to allow cell proliferation. Here, we show that several cell types can proliferate in the absence of all G1 cyclins. However, following ablation of G1 cyclins, embryonic stem (ES) cells attenuated their pluripotent characteristics, with the majority of cells acquiring the trophectodermal cell fate. We established that G1 cyclins, together with their associated cyclin-dependent kinases (CDKs), phosphorylate and stabilize the core pluripotency factors Nanog, Sox2 and Oct4. Treatment of murine ES cells, patient-derived glioblastoma tumour-initiating cells, or triple-negative breast cancer cells with a CDK inhibitor strongly decreased Sox2 and Oct4 levels. Our findings suggest that CDK inhibition might represent an attractive therapeutic strategy by targeting glioblastoma tumour-initiating cells, which depend on Sox2 to maintain their tumorigenic potential.

Proliferation and apoptosis processes in the seasonal testicular development of the wild Daurian ground squirrel (Citellus dauricus Brandt, 1844)

The aim of the present study was to elucidate the regulatory role of cell proliferation and apoptosis in testicular development of wild Daurian ground squirrels during the breeding season (April), the non-breeding season (June) and before hibernation (September). Gross mass and hormonal analysis showed that the testis : body mass ratio and plasma testosterone concentration fluctuated seasonally, with a peak in April and lowest values in June. Similarly, spermatogenesis was fully developed in April but suppressed in June and September. Testicular decellularisation and vacuolisation was seen during the transition from the breeding to the non-breeding season. Furthermore, testicular levels of proliferating cell nuclear antigen, cyclin D2 and caspase-3 protein were significantly increased in June and September. Intriguingly, positive terminal deoxyribonucleotidyl transferase-mediated dUTP–digoxigenin nick end-labelling staining and nuclear translocation of caspase-3 in testicular germ cells appeared only during the prehibernation period, whereas accumulation of cyclin D2 in spermatocyte nuclei occurred in September. These findings demonstrate, for the first time, that both cell proliferation and apoptosis are stimulated during the prehibernation period, indicating that a hormonal-regulated balance of testicular germ cell proliferation and apoptosis may play a pivotal role in preparing for testicular recrudescence of wild Daurian ground squirrels.

Hsa-miR-326 targets CCND1 and inhibits non-small cell lung cancer development

Hsa-miRNA-326 (miR-326) has recently been discovered having anticancer efficacy in different organs. However, the role of miR-326 on non-small cell lung cancer (NSCLC) is still ambiguous. In this study, we investigated the role of miR-326 on the development of NSCLC. The results indicated that miR-326 was significantly down-regulated in primary tumor tissues and very low levels were found in NSCLC cell lines. Ectopic expression of miR-326 in NSCLC cell lines significantly suppressed cell growth as evidenced by cell viability assay, colony formation assay and BrdU staining, through inhibition of cyclin D1, cyclin D2, CDK4 and up-regulation of p57(Kip2) and p21(Waf1/Cip1). In addition, miR-326 induced apoptosis, as indicated by concomitantly with up-regulation of key apoptosis protein cleaved caspase-3, and down-regulation of anti-apoptosis protein Bcl2. Moreover, miR-326 inhibited cellular migration and invasiveness through inhibition of matrix metalloproteinases (MMP)-7 and MMP-9. Further, oncogene CCND1 was revealed to be a putative target of miR-326, which was inversely correlated with miR-326 expression in NSCLC. Taken together, our results demonstrated that miR-326 played a pivotal role on NSCLC through inhibiting cell proliferation, migration, invasion, and promoting apoptosis by targeting oncogenic CCND1.

Ipsilateral and Contralateral Retinal Ganglion Cells Express Distinct Genes during Decussation at the Optic Chiasm

The increasing availability of transcriptomic technologies within the last decade has facilitated high-throughput identification of gene expression differences that define distinct cell types as well as the molecular pathways that drive their specification. The retinal projection neurons, retinal ganglion cells (RGCs), can be categorized into distinct morphological and functional subtypes and by the laterality of their projections. Here, we present a method for purifying the sparse population of ipsilaterally projecting RGCs in mouse retina from their contralaterally projecting counterparts during embryonic development through rapid retrograde labeling followed by fluorescence-activated cell sorting. Through microarray analysis, we uncovered the distinct molecular signatures that define and distinguish ipsilateral and contralateral RGCs during the critical period of axonal outgrowth and decussation, with more than 300 genes differentially expressed within these two cell populations. Among the differentially expressed genes confirmed through in vivo expression validation, several genes that mark “immaturity” are expressed within postmitotic ipsilateral RGCs. Moreover, at least one complementary pair, Igf1 and Igfbp5, is upregulated in contralateral or ipsilateral RGCs, respectively, and may represent signaling pathways that determine ipsilateral versus contralateral RGC identity. Importantly, the cell cycle regulator cyclin D2 is highly expressed in peripheral ventral retina with a dynamic expression pattern that peaks during the period of ipsilateral RGC production. Thus, the molecular signatures of ipsilateral and contralateral RGCs and the mechanisms that regulate their differentiation are more diverse than previously expected.

G protein-coupled receptors (GPCRs) That Signal via Protein Kinase A (PKA) Cross-talk at Insulin Receptor Substrate 1 (IRS1) to Activate the phosphatidylinositol 3-kinase (PI3K)/AKT Pathway

G protein-coupled receptors (GPCRs) activate PI3K/v-AKT thymoma viral oncoprotein (AKT) to regulate many cellular functions that promote cell survival, proliferation, and growth. However, the mechanism by which GPCRs activate PI3K/AKT remains poorly understood. We used ovarian preantral granulosa cells (GCs) to elucidate the mechanism by which the GPCR agonist FSH via PKA activates the PI3K/AKT cascade. Insulin-like growth factor 1 (IGF1) is secreted in an autocrine/paracrine manner by GCs and activates the IGF1 receptor (IGF1R) but, in the absence of FSH, fails to stimulate YXXM phosphorylation of IRS1 (insulin receptor substrate 1) required for PI3K/AKT activation. We show that PKA directly phosphorylates the protein phosphatase 1 (PP1) regulatory subunit myosin phosphatase targeting subunit 1 (MYPT1) to activate PP1 associated with the IGF1R-IRS1 complex. Activated PP1 is sufficient to dephosphorylate at least four IRS1 Ser residues, Ser³¹⁸, Ser³⁴⁶, Ser⁶¹², and Ser⁷⁸⁹, and promotes IRS1 YXXM phosphorylation by the IGF1R to activate the PI3K/AKT cascade. Additional experiments indicate that this mechanism also occurs in breast cancer, thyroid, and preovulatory granulosa cells, suggesting that the PKA-dependent dephosphorylation of IRS1 Ser/Thr residues is a conserved mechanism by which GPCRs signal to activate the PI3K/AKT pathway downstream of the IGF1R.

Melatonin and its receptor MT1 are involved in the downstream reaction to luteinizing hormone and participate in the regulation of luteinization in different species

The functions of melatonin in preovulatory fluid remain elusive. In the current study, we observed that the extremely high level of expression of MT1 in mice granulosa cells was rapidly induced by hCG (equivalent LH) within 2 hours and this was referred as MT1 surge. In cumulus cells, serotonin N-acetyltransferase (SNAT) was also upregulated by hCG and led to elevated melatonin levels in ovarian follicle fluid. Melatonin application before MT1 surge significantly promoted embryo implantation, and this was probably attributed to a rise in progesterone levels in the serum. The mechanistic studies indicated that melatonin/MT1 (MLT/MT1) signaling remarkably improved the expression of corpus luteum marker genes, that is, Akr1c18 and Cyp11a1. High-throughput sequencing results suggested that extracellular matrix (ECM) receptor interaction, focal adhesion, and activation of PI3K/Akt pathway which are involved in granulosa cell luteinization might mediate the actions of MLT/MT1 signal. In addition, this effect on luteinization was compared in different species. It was verified that high melatonin levels exist in serum at estrum of cows and help to improve the first estrus fecundation rate. These results suggested that both melatonin and MT1 are involved in the downstream reaction of hCG (LH) and they play important roles in luteinization. These findings provide the novel information on the physiology of melatonin in animal reproduction.

The Silencing of CCND2 by Promoter Aberrant Methylation in Renal Cell Cancer and Analysis of the Correlation between CCND2 Methylation Status and Clinical Features

Cyclin D2 (CCND2) is a member of the D-type cyclins, which plays a pivotal role in cell cycle regulation, differentiation and malignant transformation. However, its expression status and relative regulation mechanism remains unclear in renal cell cancer (RCC). In our study, the mRNA expression level of CCND2 is down-regulated in 22/23 paired RCC tissues (p<0.05). In addition, its protein expression level is also decreased in 43/43 RCC tumor tissues compared with its corresponding non-malignant tissues (p<0.001). We further detected that CCND2 was down-regulated or silenced in 6/7 RCC cell lines, but expressed in “normal” human proximal tubular (HK-2) cell line. Subsequently, MSP and BGS results showed that the methylation status in CCND2 promoter region is closely associated with its expression level in RCC cell lines. Treatment with 5-Aza with or without TSA restored CCND2 expression in several methylated RCC cell lines. Among the 102 RCC tumors, methylation of CCND2 was detected in 29/102 (28%) cases. Only 2/23 (8.7%) adjacent non-malignant tissues showed methylation. We then analyzed the correlation of clinical features and its promoter methylation. Collectively, our data suggested that loss of CCND2 expression is closely associated with the promoter aberrant methylation.

Transcriptome analysis of tetraploid cells identifies cyclin D2 as a facilitator of adaptation to genome doubling in the presence of p53

Tetraploidization, or genome doubling, is a prominent event in tumorigenesis, primarily because cell division in polyploid cells is error-prone and produces aneuploid cells. This study investigates changes in gene expression evoked in acute and adapted tetraploid cells and their effect on cell-cycle progression. Acute polyploidy was generated by knockdown of the essential regulator of cytokinesis anillin, which resulted in cytokinesis failure and formation of binucleate cells, or by chemical inhibition of Aurora kinases, causing abnormal mitotic exit with formation of single cells with aberrant nuclear morphology. Transcriptome analysis of these acute tetraploid cells revealed common signatures of activation of the tumor-suppressor protein p53. Suppression of proliferation in these cells was dependent on p53 and its transcriptional target, CDK inhibitor p21. Rare proliferating tetraploid cells can emerge from acute polyploid populations. Gene expression analysis of single cell-derived, adapted tetraploid clones showed up-regulation of several p53 target genes and cyclin D2, the activator of CDK4/6/2. Overexpression of cyclin D2 in diploid cells strongly potentiated the ability to proliferate with increased DNA content despite the presence of functional p53. These results indicate that p53-mediated suppression of proliferation of polyploid cells can be averted by increased levels of oncogenes such as cyclin D2, elucidating a possible route for tetraploidy-mediated genomic instability in carcinogenesis.

Factors which Determine the Age of the Menopause

Menopause is the final cessation of menstruation. Humans are the only primates to experience a menopause, and its origins and purpose remain unclear. The age of menopause has remained constant since Aristotle, although the age of menarche has fallen in the past 100 years. The incidence of natural premature ovarian failure before age 40 is 1%. The factors controlling the timing of the menopause are not well understood. The possession of two X chromosomes is essential for normal ovarian function. Genetic, reproductive and lifestyle factors, chemotherapy and radiation, pelvic surgery, infection, and autoimmunity have all been implicated. There is an association between age of menopause of mothers and daughters and greater concordance with identical than non-identical twins. However, with the exception of smoking which advances menopause by two years, these factors have failed to show a consistent influence on age at menopause.

Long non-coding RNA NEAT1 promotes non-small cell lung cancer progression through regulation of miR-377-3p-E2F3 pathway

Recently, the long non-coding RNA (lncRNA) NEAT1 has been identified as an oncogenic gene in multiple cancer types and elevated expression of NEAT1 was tightly linked to tumorigenesis and cancer progression. However, the molecular basis for this observation has not been characterized in progression of non-small cell lung cancer (NSCLC). In our studies, we identified NEAT1 was highly expressed in patients with NSCLC and was a novel regulator of NSCLC progression. Patients whose tumors had high NEAT1 expression had a shorter overall survival than patients whose tumors had low NEAT1 expression. Further, NEAT1 significantly accelerates NSCLC cell growth and metastasis in vitro and tumor growth in vivo. Additionally, by using bioinformatics study and RNA pull down combined with luciferase reporter assays, we demonstrated that NEAT1 functioned as a competing endogenous RNA (ceRNA) for hsa-miR-377-3p, antagonized its functions and led to the de-repression of its endogenous targets E2F3, which was a core oncogene in promoting NSCLC progression. Taken together, these observations imply that the NEAT1 modulated the expression of E2F3 gene by acting as a ceRNA, which may build up the missing link between the regulatory miRNA network and NSCLC progression.

The Hippo/MST Pathway Member SAV1 Plays a Suppressive Role in Development of the Prehierarchical Follicles in Hen Ovary

The Hippo/MST signaling pathway is a critical player in controlling cell proliferation, self-renewal, differentiation, and apoptosis of most tissues and organs in diverse species. Previous studies have shown that Salvador homolog 1 (SAV1), a scaffolding protein which functions in the signaling system is expressed in mammalian ovaries and play a vital role in governing the follicle development. But the exact biological effects of chicken SAV1 in prehierarchical follicle development remain poorly understood. In the present study, we demonstrated that the SAV1 protein is predominantly expressed in the oocytes and undifferentiated granulosa cells in the various sized prehierarchical follicles of hen ovary, and the endogenous expression level of SAV1 mRNA appears down-regulated from the primordial follicles to the largest preovulatory follicles (F2-F1) by immunohistochemistry and real-time RT-PCR, respectively. Moreover, we found the intracellular SAV1 physically interacts with each of the pathway members, including STK4/MST1, STK3/MST2, LATS1 and MOB2 using western blotting. And SAV1 significantly promotes the phosphorylation of LATS1 induced by the kinase of STK4 or STK3 in vitro. Furthermore, SAV1 knockdown by small interfering RNA (siRNA) significantly increased proliferation of granulosa cells from the prehierarchical follicles (6-8 mm in diameter) by BrdU-incorporation assay, in which the expression levels of GDF9, StAR and FSHR mRNA was notably enhanced. Meanwhile, these findings were consolidated by the data of SAV1 overexpression. Taken together, the present results revealed that SAV1 can inhibit proliferation of the granulosa cells whereby the expression levels of GDF9, StAR and FSHR mRNA were negatively regulated. Accordingly, SAV1, as a member of the hippo/MST signaling pathway plays a suppressive role in ovarian follicle development by promoting phosphorylation and activity of the downstream LATS1, may consequently lead to prevention of the follicle selection during ovary development.

Regulation of the Embryonic Cell Cycle During Mammalian Preimplantation Development

The preimplantation development stage of mammalian embryogenesis consists of a series of highly conserved, regulated, and predictable cell divisions. This process is essential to allow the rapid expansion and differentiation of a single-cell zygote into a multicellular blastocyst containing cells of multiple developmental lineages. This period of development, also known as the germinal stage, encompasses several important developmental transitions, which are accompanied by dramatic changes in cell cycle profiles and dynamics. These changes are driven primarily by differences in the establishment and enforcement of cell cycle checkpoints, which must be bypassed to facilitate the completion of essential cell cycle events. Much of the current knowledge in this area has been amassed through the study of knockout models in mice. These mouse models are powerful experimental tools, which have allowed us to dissect the relative dependence of the early embryonic cell cycles on various aspects of the cell cycle machinery and highlight the extent of functional redundancy between members of the same gene family. This chapter will explore the ways in which the cell cycle machinery, their accessory proteins, and their stimuli operate during mammalian preimplantation using mouse models as a reference and how this allows for the usually well-defined stages of the cell cycle to be shaped and transformed during this unique and critical stage of development.

Hsa-miR-134 suppresses non-small cell lung cancer (NSCLC) development through down-regulation of CCND1

Hsa-miRNA-134 (miR-134) has recently been discovered to have anticancer efficacy in different organs. However, the role of miR-134 on non-small cell lung cancer (NSCLC) is still ambiguous. In this study, we investigated the role of miR-134 on the development of NSCLC. The results indicated that miR-134 was significantly down-regulated in primary tumor tissues and very low levels were found in NSCLC cell lines. Ectopic expression of miR-134 in NSCLC cell lines significantly suppressed cell growth as evidenced by cell viability assay, colony formation assay and BrdU staining, through inhibition of cyclin D1, cyclin D2, CDK4 and up-regulation of p57(Kip2) and p21(Waf1/Cip1). In addition, miR-134 induced apoptosis, as indicated by concomitantly with up-regulation of key apoptosis protein cleaved caspase-3, and down-regulation of anti-apoptosis protein Bcl2. Moreover, miR-134 inhibited cellular migration and invasiveness through inhibition of matrix metalloproteinases (MMP)-7 and MMP-9. Further, oncogene CCND1 was revealed to be a putative target of miR-134, which was inversely correlated with miR-134 expression in NSCLC. Taken together, our results demonstrated that miR-134 played a pivotal role on NSCLC through inhibiting cell proliferation, migration, invasion, and promoting apoptosis by targeting oncogenic CCND1.

Oleic acid induces specific alterations in the morphology, gene expression and steroid hormone production of cultured bovine granulosa cells

After parturition, one of the major problems related to nutritional management that is faced by the majority of dairy cows is negative energy balance (NEB). During NEB, excessive lipid mobilization takes place and hence the levels of free fatty acids, among them oleic acid, increase in the blood, but also in the follicular fluid. This accumulation can be associated with serious metabolic and reproductive disorders. In the present study, we analyzed the effects of physiological concentrations of oleic acid on cell morphology, apoptosis, necrosis, proliferation and steroid production, and on the abundance of selected transcripts in cultured bovine granulosa cells. Increasing oleic acid concentrations induced intracellular lipid droplet accumulation, thus resulting in a foam cell-like morphology, but had no effects on apoptosis, necrosis or proliferation. Oleic acid also significantly reduced the transcript abundance of the gonadotropin hormone receptors, FSHR and LHCGR, steroidogenic genes STAR, CYP11A1, HSD3B1 and CYP19A1, the cell cycle regulator CCND2, but not of the proliferation marker PCNA. In addition, treatment increased the transcript levels of the fatty acid transporters CD36 and SLC27A1, and decreased the production of 17-beta-estradiol and progesterone. From these data it can be concluded that oleic acid specifically affects morphological and physiological features and gene expression levels thus altering the functionality of granulosa cells. Suggestively, these effects might be partly due to the reduced expression of FSHR and thus the reduced responsiveness to FSH stimulation.

Inhibition of Rb Phosphorylation Leads to mTORC2-Mediated Activation of Akt

The retinoblastoma (Rb) protein exerts its tumor suppressor function primarily by inhibiting the E2F family of transcription factors that govern cell-cycle progression. However, it remains largely elusive whether the hyper-phosphorylated, non-E2F1-interacting form of Rb has any physiological role. Here we report that hyper-phosphorylated Rb directly binds to and suppresses the function of mTORC2 but not mTORC1. Mechanistically, Rb, but not p107 or p130, interacts with Sin1 and blocks the access of Akt to mTORC2, leading to attenuated Akt activation and increased sensitivity to chemotherapeutic drugs. As such, inhibition of Rb phosphorylation by depleting cyclin D or using CDK4/6 inhibitors releases Rb-mediated mTORC2 suppression. This, in turn, leads to elevated Akt activation to confer resistance to chemotherapeutic drugs in Rb-proficient cells, which can be attenuated with Akt inhibitors. Therefore, our work provides a molecular basis for the synergistic usage of CDK4/6 and Akt inhibitors in treating Rb-proficient cancer.

Mouse oocytes suppress miR-322-5p expression in ovarian granulosa cells

This study tested the hypothesis that oocyte-derived paracrine factors (ODPFs) regulate miRNA expression in mouse granulosa cells. Expression of mmu-miR-322-5p (miR-322) was higher in mural granulosa cells (MGCs) than in cumulus cells of the Graafian follicles. The expression levels of miR-322 decreased when cumulus cells or MGCs were co-cultured with oocytes denuded of their cumulus cells. Inhibition of SMAD2/3 signaling by SB431542 increased miR-322 expression by cumulus-oocyte complexes (COCs). Moreover, the cumulus cells but not the MGCs in Bmp15^–/–/Gdf9^+/– (double-mutant) mice exhibited higher miR-322 expression than those of wild-type mice. Taken together, these results show that ODPFs suppress the expression of miR-322 in cumulus cells. Gene ontology analysis of putative miR-322 targets whose expression was detected in MGCs with RNA-sequencing suggested that multiple biological processes are affected by miR-322 in MGCs. These results demonstrate that ODPFs regulate miRNA expression in granulosa cells and that this regulation may participate in the differential control of cumulus cell versus MGC functions. Therefore, the ODPF-mediated regulation of cumulus cells takes place at both transcriptional and post-transcriptional levels.

The cyclin D1 carboxyl regulatory domain controls the division and differentiation of hematopoietic cells

Background

The family of D cyclins has a fundamental role in cell cycle progression, but its members (D1, D2, D3) are believed to have redundant functions. However, there is some evidence that contradicts the notion of mutual redundancy and therefore this concept is still a matter of debate.

Results

Our data show that the cyclin D1 is indispensable for normal hematopoiesis. Indeed, in the absence of D1, either in genetic deficient mice, or after acute ablation by RNA interference, cyclins D2 and D3 are also not expressed preventing hematopoietic cell division and differentiation at its earliest stage. This role does not depend on the cyclin box, but on the carboxyl regulatory domain of D1 coded by exons 4–5, since hematopoietic differentiation is also blocked by the conditional ablation of this region.

Conclusion

These results demonstrate that not all functions of individual D cyclins are redundant and highlight a master role of cyclin D1 in hematopoiesis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13062-016-0122-9) contains supplementary material, which is available to authorized users.

Transcriptomic analysis of stage 1 versus advanced adult granulosa cell tumors

Ovarian granulosa cell tumors (GCT) are hormonally-active neoplasms characterized, in the adult-subtype, by a mutation in the FOXL2 gene (C134W). They exhibit an indolent course with an unexplained propensity for late recurrence; ~80% of patients with aggressive, advanced stage tumors die from their disease; aside from surgery, therapeutic options are limited. To identify the molecular basis of advanced stage disease we have used whole transcriptome analysis of FOXL2 C134W mutation positive adult (a)GCT to identify genes that are differentially expressed between early (stage 1) and advanced (stage 3) aGCT. Transcriptome profiles for early (n = 6) and stage 3 (n = 6) aGCT, and for the aGCT-derived KGN, cell line identified 24 genes whose expression significantly differs between the early and stage 3 aGCT. Of these, 16 were more abundantly expressed in the stage 3 aGCT and 8 were higher in the stage 1 tumors. These changes were further examined for the genes which showed the greatest fold change: the cytokine CXCL14, microfibrillar-associated protein 5, insulin-like 3 and desmin. Gene Set Enrichment Analysis identified overexpression of genes on chromosome 7p15 which includes the homeobox A gene locus. The analysis therefore identifies a small number of genes with clearly discriminate patterns of expression arguing that the clinicopathological-derived distinction of the tumor stage is robust, whilst confirming the relative homogeneity of expression for many genes across the cohort and hence of aGCT. The expression profiles do however identify several overexpressed genes in both stage 1 and/or stage 3 aGCT which warrant further study as possible therapeutic targets.

Roles of epidermal growth factor (EGF)-like factor in the ovulation process

Luteinizing hormone (LH) surge stimulates preovulatory follicles to induce the ovulation process, including oocyte maturation, cumulus expansion, and granulosa cell luteinization. The matured oocytes surrounded by an expanded cumulus cell layer are released from follicles to the oviduct. However, LH receptors are dominantly expressed in granulosa cells, but less in cumulus cells and are not expressed in oocytes, indicating that the secondary factors expressed and secreted from LH-stimulated granulosa cells are required for the induction of the ovulation process. Prostaglandin and progesterone are well-known factors that are produced in granulosa cells and then stimulate in both granulosa and cumulus cells. The mutant mice of prostaglandin synthase (Ptgs2KO mice) or progesterone receptor (PRKO mice) revealed that the functions were essential to accomplish the ovulation process, but not to induce the ovulation process. To identify the factors initiating the transfer of the stimuli of LH surge from granulosa cells to cumulus cells, M. Conti's lab and our group performed microarray analysis of granulosa cells and identified the epidermal growth factor (EGF)-like factor, amphiregulin (AREG), epiregulin (EREG), and β-cellulin (BTC) that act on EGF receptor (EGFR) and then induce the ERK1/2 and Ca²⁺-PLC pathways in cumulus cells. When each of the pathways was down-regulated using a pharmacological approach or gene targeting study, the induction of cumulus expansion and oocyte maturation were dramatically suppressed, indicating that both pathways are inducers of the ovulation process. However, an in vitro culture study also revealed that the EGFR-induced unphysiological activation of PKC in cumulus cells accelerated oocyte maturation with low cytostatic activity. Thus, the matured oocytes are not arrested at the metaphase II (MII) stage and then spontaneously form pronuclei. The expression of another type of EGF-like factor, neuregulin 1 (NRG1), that does not act on EGFR, but selectively binds to ErbB3 is observed in granulosa cells after the LH surge. NRG1 supports EGFR-induced ERK1/2 phosphorylation, but reduces PKC activity to physiological level in the cumulus cells, which delays the timing of meiotic maturation of oocytes to adjust the timing of ovulation. Thus, both types of EGF-like factor are rapidly induced by LH surge and then stimulate cumulus cells to control ERK1/2 and PKC pathways, which results in the release of matured oocytes with a fertilization competence.

Mouse models of adrenocortical tumors

The molecular basis of the organogenesis, homeostasis, and tumorigenesis of the adrenal cortex has been the subject of intense study for many decades. Specifically, characterization of tumor predisposition syndromes with adrenocortical manifestations and molecular profiling of sporadic adrenocortical tumors have led to the discovery of key molecular pathways that promote pathological adrenal growth. However, given the observational nature of such studies, several important questions regarding the molecular pathogenesis of adrenocortical tumors have remained. This review will summarize naturally occurring and genetically engineered mouse models that have provided novel tools to explore the molecular and cellular underpinnings of adrenocortical tumors. New paradigms of cancer initiation, maintenance, and progression that have emerged from this work will be discussed.

Development and characterization of a novel long-acting recombinant follicle stimulating hormone agonist by fusing Fc to an FSH-β subunit

STUDY QUESTION

Does a novel long-acting recombinant human FSH, KN015, a heterodimer composed of FSHα and FSHβ-Fc/Fc, offer a potential FSH alternative?

SUMMARY ANSWER

KN015 had in vitro activity and superior in vivo bioactivity than recombinant human FSH (rhFSH), suggesting KN015 could serve as a potential FSH agonist for clinical therapy.

WHAT IS KNOWN ALREADY

rhFSH has very short half-life so that repeat injections are needed, resulting in discomfort and inconvenience for patients. The longest-acting rhFSH available in clinics is corifollitropin alpha (FSH-CTP), but its half-life is not long enough to sustain the whole therapy period, and additional injections of rhFSH are needed.

STUDY DESIGN, SIZE, DURATION

Plasmids containing FSHα, FSHβ-Fc and Fc cDNA were transfected into Chinese hamster ovary (CHO) cells for KN015 production. The pharmacokinetics of KN015 was investigated in 6-week-old SD rats (n = 6/group) and healthy Cynomolgus monkeys in two different dose groups (n = 2/group). A series of experiments were designed for in vitro and in vivo characterization of the bioactivity of KN015 relative to rhFSH.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The purity and molecular weight of KN015 were determined by reducing and non-reducing SDS-PAGE. To measure KN015 half-life, sera were collected at increasing time points and the remaining FSH concentration was measured by enzyme-linked immunosorbent assay. To assess the bioactivity of KN015 versus rhFSH in vitro, firstly cAMP production was assessed in CHO cells expressing FSH receptor (FSHR) with the treatment of Fc/Fc, rhFSH or KN015 at eight different doses (0.03, 0.09, 0.28, 0.83, 2.5, 7.5, 22.5, 67.5 nM), and secondly cumulus oocyte complexes (COCs; n = 20/group) of ICR mice (primed-PMSG 44 h before sacrificed) were collected and cultured in medium containing 1.25 pM Fc/Fc, rhFSH or KN015 at 37°C and then germinal vesicle breakdown (GVBD) and COC expansion were observed at 4 and 16 h, respectively. The in vivo activity of KN015 was compared with rhFSH by ovary weight gain and ovulation assays. In the former, ovary weight gains in 21-day-old female SD rats, after a single subcutaneous injection of KN015, were compared with those after several injections of rhFSH over a range of doses (n = 8/group). Sera were harvested for estradiol (E2) analysis, and the ovaries were processed for hematoxylin and eosin (HE) staining, immunohistochemistry (IHC), TdT (terminal deoxynucleotidyl transferase)-mediated dUDP nick-end labeling (TUNEL), RT-PCR and western blot. In the latter, 26-day-old female SD rats (n = 8/group) were injected with different doses of KN015 or rhFSH, and were sacrificed at 24 h after an injection of hCG (20 IU/rat). Moreover, the molecular responses stimulated by KN015 or rhFSH in the ovary were also analyzed through detecting expression of the FSH target genes (Cyp19a1, Fshr and Lhcgr) and phosphatidylinositide 3-kinase (PI3K) pathway activation.

MAIN RESULTS AND THE ROLE OF CHANCE

KN015 has a molecular weight of 82 kD and its half-life is 84 h in SD rats (10-fold longer than that of rhFSH) and 215 h in Cynomolgus monkeys. The EC50 value of the cAMP induction in CHO cells (KN015 versus rhFSH, 1.84 versus 0.87 nM), COC expansion and oocyte maturation assays showed KN015 had approximately half of rhFSH's activity in vitro. A single dose of KN015 (1.5 pmol/rat, 166.1 ± 19.7 mg, P < 0.01) stimulated significantly larger ovary weight gain than several injections of rhFSH (1.5 pmol/rat, 59.3 ± 28.1 mg, P < 0.01). The serum E2 level in the KN015 group was significantly higher than that in rhFSH group. The number of oocytes obtained by ovulation induction was comparable with or higher in the KN015 group than in the rhFSH group. KN015 was more effective than rhFSH in inducing FSH target genes (Cyp19a1, Fshr, Lhcgr) or activating the PI3K pathway in vivo. Moreover, a single injection of KN015 promoted granulosa cell proliferation and prevented follicle atresia to the same extent as several injections of rhFSH.

LIMITATIONS, REASONS FOR CAUTION

All assays in this study were operated only in animals and clinical trials are needed to confirm they can be extrapolated to humans.

WIDER IMPLICATIONS OF THE FINDINGS

KN015 is a valuable alternative to FSH and may have great potential for therapeutic applications.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by National Basic Research Program of China (2011|CB944504, 2012CB944403) and National Natural Science Foundation of China (81172473, 31371449). The authors have no conflicts of interest to declare.

AF1q is a novel TCF7 co-factor which activates CD44 and promotes breast cancer metastasis

AF1q is an MLL fusion partner that was identified from acute myeloid leukemia (AML) patients with t (1; 11) (q21; q23) chromosomal abnormality. The function of AF1q is not yet fully known, however, elevated AF1q expression is associated with poor clinical outcomes in various malignancies. Here, we show that AF1q specifically binds to T-cell-factor-7 (TCF7) in the Wnt signaling pathway and results in transcriptional activation of CD44 as well as multiple downstream targets of the TCF7/LEF1. In addition, enhanced AF1q expression promotes breast cancer cell proliferation, migration, mammosphere formation, and chemo-resistance. In xenograft models, enforced AF1q expression in breast cancer cells also promotes liver metastasis and lung colonization. In a cohort of 63 breast cancer patients, higher percentages of AF1q-positive cancer cells in primary sites were associated with significantly poorer overall survival (OS), disease-free survival (DFS), and brain metastasis-free survival (b-MFS). Using paired primary/metastatic samples from the same patients, we demonstrate that AF1q-positive breast cancer cells become dynamically dominant in the metastatic sites compared to the primary sites. Our findings indicate that breast cancer cells with a hyperactive AF1q/TCF7/CD44 regulatory axis in the primary sites may represent "metastatic founder cells" which have invasive properties.

Heterogeneity and Bipotency of Astroglial-Like Cerebellar Progenitors along the Interneuron and Glial Lineages

Cerebellar GABAergic interneurons in mouse comprise multiple subsets of morphologically and neurochemically distinct phenotypes located at strategic nodes of cerebellar local circuits. These cells are produced by common progenitors deriving from the ventricular epithelium during embryogenesis and from the prospective white matter (PWM) during postnatal development. However, it is not clear whether these progenitors are also shared by other cerebellar lineages and whether germinative sites different from the PWM originate inhibitory interneurons. Indeed, the postnatal cerebellum hosts another germinal site along the Purkinje cell layer (PCL), in which Bergmann glia are generated up to first the postnatal weeks, which was proposed to be neurogenic. Both PCL and PWM comprise precursors displaying traits of juvenile astroglia and neural stem cell markers. First, we examine the proliferative and fate potential of these niches, showing that different proliferative dynamics regulate progenitor amplification at these sites. In addition, PCL and PWM differ in the generated progeny. GABAergic interneurons are produced exclusively by PWM astroglial-like progenitors, whereas PCL precursors produce only astrocytes. Finally, through in vitro, ex vivo, and in vivo clonal analyses we provide evidence that the postnatal PWM hosts a bipotent progenitor that gives rise to both interneurons and white matter astrocytes.