scholarly journals Kisspeptin cell-specific PI3K signaling regulates hypothalamic kisspeptin expression and participates in the regulation of female fertility

2014 ◽  
Vol 307 (11) ◽  
pp. E969-E982 ◽  
Author(s):  
Matthew Beymer ◽  
Ariel L. Negrón ◽  
Guiqin Yu ◽  
Samuel Wu ◽  
Christian Mayer ◽  
...  
Keyword(s):  
Intracellular Signaling ◽  
Pubertal Development ◽  
Cell Number ◽  
Pi3k Signaling ◽  
Catalytic Subunits ◽  
Gnrh Release ◽  
Estrous Cyclicity ◽  
Males And Females ◽  
Specific Deletion

Hypothalamic kisspeptin neurons integrate and translate cues from the internal and external environments that regulate gonadotropin-releasing hormone (GnRH) secretion and maintain fertility in mammals. However, the intracellular signaling pathways utilized to translate such information into changes in kisspeptin expression, release, and ultimately activation of the kisspeptin-receptive GnRH network have not yet been identified. PI3K is an important signaling node common to many peripheral factors known to regulate kisspeptin expression and GnRH release. We investigated whether PI3K signaling regulates hypothalamic kisspeptin expression, pubertal development, and adult fertility in mice. We generated mice with a kisspeptin cell-specific deletion of the PI3K catalytic subunits p110α and p110β (kiss-p110α/β-KO). Using in situ hybridization, we examined Kiss1 mRNA expression in gonad-intact, gonadectomized (Gdx), and Gdx + steroid-replaced mice. Kiss1 cell number in the anteroventral periventricular hypothalamus (AVPV) was significantly reduced in intact females but not in males. In contrast, compared with WT and regardless of steroid hormone status, Kiss1 cell number was lower in the arcuate (ARC) of kiss-p110α/β-KO males, but it was unaffected in females. Both intact Kiss-p110α/β-KO males and females had reduced ARC kisspeptin-immunoreactive (IR) fibers compared with WT animals. Adult kiss-p110α/β-KO males had significantly lower circulating luteinizing hormone (LH) levels, whereas pubertal development and fertility were unaffected in males. Kiss-p110α/β-KO females exhibited a reduction in fertility despite normal pubertal development, LH levels, and estrous cyclicity. Our data show that PI3K signaling is important for the regulation of hypothalamic kisspeptin expression and contributes to normal fertility in females.

scholarly journals Uncovering Novel Reproductive Defects in Neurokinin B Receptor Null Mice: Closing the Gap Between Mice and Men

Endocrinology ◽  
2012 ◽  
Vol 153 (3) ◽  
pp. 1498-1508 ◽  
Author(s):  
Jasmine J. Yang ◽  
Claudia S. Caligioni ◽  
Yee-Ming Chan ◽  
Stephanie B. Seminara
Keyword(s):  
Pubertal Development ◽  
Hypogonadotropic Hypogonadism ◽  
Corpora Lutea ◽  
Wild Type ◽  
Neurokinin B ◽  
Gnrh Release ◽  
Estrous Cyclicity ◽  
Closing The Gap ◽  
Deficient Mice ◽  
Robust Response

Patients bearing mutations in TAC3 and TACR3 (which encode neurokinin B and its receptor, respectively) have sexual infantilism and infertility due to GnRH deficiency. In contrast, Tacr3−/− mice have previously been reported to be fertile. Because of this apparent phenotypic discordance between mice and men bearing disabling mutations in Tacr3/TACR3, Tacr3 null mice were phenotyped with close attention to pubertal development, estrous cyclicity, and fertility. Tacr3−/− mice demonstrated normal timing of preputial separation and day of first estrus, markers of sexual maturation. However, at postnatal d 60, Tacr3−/− males had significantly smaller testes and lower FSH levels than their wild-type littermates. Tacr3−/− females had lower uterine weights and abnormal estrous cyclicity. Approximately half of Tacr3−/− females had no detectable corpora lutea on ovarian histology at postnatal d 60. Despite this apparent ovulatory defect, all Tacr3−/− females achieved fertility when mated. However, Tacr3−/− females were subfertile, having both reduced numbers of litters and pups per litter. The subfertility of these animals was not due to a primary ovarian defect, because they demonstrated a robust response to exogenous gonadotropins. Thus, although capable of fertility, Tacr3-deficient mice have central reproductive defects. The remarkable ability of acyclic female Tacr3 null mice to achieve fertility is reminiscent of the reversal of hypogonadotropic hypogonadism seen in a high proportion of human patients bearing mutations in TACR3. Tacr3 mice are a useful model to examine the mechanisms by which neurokinin B signaling modulates GnRH release.

scholarly journals PRKAR2A deficiency protects mice from experimental colitis by increasing IFN-stimulated gene expression and modulating the intestinal microbiota

2021 ◽  
Author(s):  
Lumin Wei ◽  
Rongjing Zhang ◽  
Jinzhao Zhang ◽  
Juanjuan Li ◽  
Deping Kong ◽  
...  
Keyword(s):  
Experimental Colitis ◽  
Regulatory Subunit ◽  
Protective Effects ◽  
Intestinal Epithelial ◽  
Catalytic Subunits ◽  
Regulatory Subunits ◽  
Pka Regulatory Subunit ◽  
Cross Fostering ◽  
Specific Deletion

AbstractProtein kinase A (PKA) plays an important role in regulating inflammation via its catalytic subunits. Recently, PKA regulatory subunits have been reported to directly modulate some signaling pathways and alleviate inflammation. However, the role of PKA regulatory subunits in colonic inflammation remains unclear. Therefore, we conducted this study to investigate the role of the PKA regulatory subunit PRKAR2A in colitis. We observed that PRKAR2A deficiency protected mice from dextran sulfate sodium (DSS)-induced experimental colitis. Our experiments revealed that the intestinal epithelial cell-specific deletion of Prkar2a contributed to this protection. Mechanistically, the loss of PRKAR2A in Prkar2a−/− mice resulted in an increased IFN-stimulated gene (ISG) expression and altered gut microbiota. Inhibition of ISGs partially reversed the protective effects against DSS-induced colitis in Prkar2a−/− mice. Antibiotic treatment and cross-fostering experiments demonstrated that the protection against DSS-induced colitis in Prkar2a−/− mice was largely dependent on the gut microflora. Altogether, our work demonstrates a previously unidentified function of PRKAR2A in promoting DSS-induced colitis.

scholarly journals Development, Sex Steroid Regulation, and Phenotypic Characterization of RFamide-Related Peptide (Rfrp) Gene Expression and RFamide Receptors in the Mouse Hypothalamus

Endocrinology ◽  
2012 ◽  
Vol 153 (4) ◽  
pp. 1827-1840 ◽  
Author(s):  
Matthew C. Poling ◽  
Joshua Kim ◽  
Sangeeta Dhamija ◽  
Alexander S. Kauffman
Keyword(s):  
In Situ Hybridization ◽  
Estrogen Receptor Α ◽  
Cell Number ◽  
Phenotypic Characterization ◽  
Related Peptide ◽  
Adult Mice ◽  
Gnrh Neurons ◽  
Double Label ◽  
Hormonal Milieu

Arginine-phenylalanine-amide (RFamide)-related peptide 3 (RFRP-3, encoded by the Rfrp gene) is the mammalian ortholog of gonadotropin-inhibiting hormone and can inhibit GnRH neuronal activity and LH release. However, the development and regulation of the RFRP-3 system in both sexes is poorly understood. Using in situ hybridization, we examined changes in Rfrp-expressing neurons in mice of both sexes during development and under different adulthood hormonal milieus. We found no sex differences in Rfrp expression or cell number in adult mice. Interestingly, we identified two interspersed subpopulations of Rfrp cells (high Rfrp-expressing, HE; low Rfrp-expressing, LE), which have unique developmental and steroidal regulation characteristics. The number of LE cells robustly decreases during postnatal development, whereas HE cell number increases significantly before puberty. Using Bax knockout mice, we determined that the dramatic developmental decrease in LE Rfrp cells is not due primarily to BAX-dependent apoptosis. In adults, we found that estradiol and testosterone moderately repress Rfrp expression in both HE and LE cells, whereas the nonaromatizable androgen dihydrotestosterone has no effect. Using double-label in situ hybridization, we determined that approximately 25% of Rfrp neurons coexpress estrogen receptor-α in each sex, whereas Rfrp cells do not readily express androgen receptor in either sex, regardless of hormonal milieu. Lastly, when we looked at RFRP-3 receptors, we detected some coexpression of Gpr147 but no coexpression of Gpr74 in GnRH neurons of both intact and gonadectomized males and females. Thus, RFRP-3 may exert its effects on reproduction either directly, via Gpr147 in a subset of GnRH neurons, and/or indirectly, via upstream regulators of GnRH.

scholarly journals A new species of pygmy Paroctopus (Cephalopoda: Octopodidae): the smallest southwestern Atlantic octopod, found in sea debris

2021 ◽  
Author(s):  
Tatiana S. Leite ◽  
Erica A.G. Vidal ◽  
Françoise Dantas Lima ◽  
Sergio M.Q. Lima ◽  
Ricardo M Dias ◽  
...  
Keyword(s):  
New Species ◽  
Western Atlantic ◽  
Bayesian Phylogenetic Analysis ◽  
History Of ◽  
Novel Habitat ◽  
In Situ Observations ◽  
Males And Females ◽  
The Relationship ◽  
A New Species

Abstract The new species, Paroctopus cthulu sp. nov. Leite, Haimovici, Lima and Lima, was recorded from very shallow coastal waters on sandy/muddy and shelter-poor bottoms with natural and human-origin debris. It is a small octopus, adults are less than 35 mm mantle length (ML) and weigh around 15 g. It has short to medium sized arms, enlarged suckers on the arms of both males and females, large posterior salivary glands (25 %ML), a relatively large beak (9 % ML) and medium to large mature eggs (3.5 to > 9 mm). The characteristics of hatchlings of two brooding females, some of their anatomical features, and in-situ observations of their behaviour are a clue to the life history of it and closely related pygmy octopuses. The Bayesian phylogenetic analysis showed that Paroctopus cthulu sp.nov. specimens grouped in a well-supported clade of Paroctopus species, separate from P.joubini and P. cf mercatoris from the Northwestern Atlantic . The description of this new species, living in a novel habitat of human debris in shallow water off Brazil, offered an opportunity not only to evaluate the relationship among the small octopuses of the western Atlantic, Caribbean and eastern Pacific, but also their adaptation to the Anthropocene period.

The Role of miRNAs in PI3K Signaling Pathway in Blood Malignancies: A Review Article

2021 ◽  
Author(s):  
Haniyeh Gaffari-Nazari ◽  
Samira Karami ◽  
Leila Noorazar ◽  
Sayeh Parkhideh ◽  
Elham Roshandel ◽  
...  
Keyword(s):  
Treatment Failure ◽  
Signaling Pathway ◽  
Intracellular Signaling ◽  
Pi3k Pathway ◽  
Pi3k Signaling ◽  
Laboratory Findings ◽  
A Cell ◽  
Pi3k Signaling Pathway ◽  
Relationship Of

Background: The PI3K/Akt/mTOR signaling pathway is one of the most important intracellular signaling pathways by regulating the cell cycle process. The direct relationship of this pathway with important mechanisms such as cell quiescence, longevity, and proliferation has been established. The overactive PI3K pathway with decreased and increased apoptosis and cell proliferation respectively is involved in pathogenesis of many cancers, including blood malignancies such as leukemia. Methods: Laboratory findings have shown that different factors, such as miRNAs, play a role in regulating PI3K signaling pathway. These molecules can alter the fate of a cell by interfering in suppression/overexpression of mRNA, transcription factors or stimulating the transcription of some genes. In this article, we reviewed the role of miRNAs in regulating the PI3K/Akt/mTOR pathway and its effect on leukemic progression and treatment failure. Conclusion: At present, miRNAs are known to be one of the causes of treatment failure and relapse in cancers.

scholarly journals Phosphatidylinositide 3-kinase localizes to cytoplasmic lipid bodies in human polymorphonuclear leukocytes and other myeloid-derived cells

Blood ◽  
2000 ◽  
Vol 95 (3) ◽  
pp. 1078-1085 ◽  
Author(s):  
Wengui Yu ◽  
Jessica Cassara ◽  
Peter F. Weller
Keyword(s):  
Intracellular Signaling ◽  
Polymorphonuclear Leukocytes ◽  
Membrane Receptors ◽  
Lipid Bodies ◽  
Catalytic Subunits ◽  
Lyn Kinase ◽  
Key Enzyme ◽  
Intracellular Vesicles ◽  
Plasma Membrane Receptors ◽  
Human Polymorphonuclear Leukocytes

Phosphatidylinositide 3-kinase (PI3K) is a key enzyme implicated in intracellular signaling of diverse cellular responses including receptor-mediated responses and neutrophil activation. Several PI3K subunits have been cloned and shown to be localized to plasma membrane receptors, the cytosol, or intracellular vesicles or caveolae. We report the localization of PI3K to a distinct intracellular site, cytoplasmic lipid bodies, in leukocytes. In U937 monocyte cells, PI3K p85 regulatory and p110β catalytic subunits were localized to lipid bodies by immunocytochemistry and/or immunoblotting and enzyme assays of subcellular fractions. In RAW murine macrophages, p55, p85, and p85β PI3K subunits were present at isolated lipid bodies. PI3K p85 was also shown to colocalize and, by co-immunoprecipitation, to be physically associated with phosphorylated Lyn kinase in lipid bodies induced to form in human polymorphonuclear leukocytes. These findings, therefore, indicate a novel site for PI3K compartmentalization and suggest that PI3K-mediated signaling is active within cytoplasmic lipid bodies in leukocytes.

scholarly journals Repetitive Activation of Hypothalamic G Protein-Coupled Receptor 54 with Intravenous Pulses of Kisspeptin in the Juvenile Monkey (Macaca mulatta) Elicits a Sustained Train of Gonadotropin-Releasing Hormone Discharges

Endocrinology ◽  
2006 ◽  
Vol 147 (2) ◽  
pp. 1007-1013 ◽  
Author(s):  
Tony M. Plant ◽  
Suresh Ramaswamy ◽  
Meloni J. DiPietro
Keyword(s):  
G Protein ◽  
Concomitant Treatment ◽  
Secondary Effects ◽  
G Protein Coupled Receptor ◽  
Gnrh Release ◽  
Dependent Signal ◽  
Lh Release ◽  
Lh Secretion ◽  
G Protein Coupled

The purpose of the present study was to further examine the hypothesis that activation of G protein-coupled receptor 54 (GPR54) signaling at the end of the juvenile phase of primate development is responsible for initiation of gonadarche and the onset of puberty. Accordingly, we determined whether repetitive iv administration of the GPR54 receptor agonist kisspeptin-10 (2 μg as a brief 1-min infusion once every hour for 48 h) to the juvenile male rhesus monkey would prematurely elicit sustained, pulsatile release of hypothalamic GnRH, the neuroendocrine trigger for gonadarche. GnRH release was monitored indirectly by measuring LH secretion from the in situ pituitary, the GnRH responsiveness of which had been heightened before the experiment with an intermittent iv infusion of synthetic GnRH. Agonadal animals (n = 4) were employed to eliminate any confounding and secondary effects of changing feedback signals from the testis. The first brief infusion of kisspeptin-10 evoked an LH discharge that mimicked those produced by GnRH priming, and this was followed by a train of similar LH discharges in response to hourly activation of GPR54 by repetitive kisspeptin-10 administration. Concomitant treatment with a GnRH receptor antagonist, acyline, abolished kisspeptin-10-induced LH release. Repetitive kisspeptin-10 administration also provided a GnRH-dependent signal to FSH secretion. These findings are consistent with the notion that, in primates, the transition from the juvenile (attenuated GnRH release) to pubertal (robust GnRH release) state is controlled by activation of GPR54 resulting from increased expression of hypothalamic KiSS-1 and release of kisspeptin in this region of the brain.

The effect of methoxychlor on carbon assimilation by freshwater phytoplankton

1976 ◽  
Vol 54 (24) ◽  
pp. 2848-2851 ◽  
Author(s):  
Deanna L. Page ◽  
Brian Colman
Keyword(s):  
Algal Species ◽  
Carbon Assimilation ◽  
Cell Number ◽  
Technical Grade ◽  
Freshwater Phytoplankton ◽  
Photosynthetic Carbon ◽  
Photosynthetic Carbon Assimilation ◽  
Natural Phytoplankton

The effect of the insecticide methoxychlor (2,2-bis(p-methoxyphenyl)-1,1,1-trichloroethane) on photosynthetic carbon assimilation by natural phytoplankton populations was determined by incubation of plankton samples in situ at a 1.0-metre depth with [14C]bicarbonate for 4-h periods with or without 100 parts per billion (ppb) (100 μg/l) pure or technical grade methoxychlor. The different algal populations occurring over a 5-week period in May and June in Lake Opinicon, Leeds County, Ontario, were found, in 19 experiments, to be seldom affected by the insecticide. In the few cases where carbon assimilation in methoxychlor-treated samples was found to be significantly lower than that of the controls, the inhibition ranged in extent from 9.7% to 67.4% and these effects could not be correlated unequivocally with cell number or with the presence of any particular algal species.

scholarly journals Meiotic Cohesion Requires Accumulation of ORD on Chromosomes before Condensation

2002 ◽  
Vol 13 (11) ◽  
pp. 3890-3900 ◽  
Author(s):  
Eric M. Balicky ◽  
Matthew W. Endres ◽  
Cary Lai ◽  
Sharon E. Bickel
Keyword(s):  
Chromosome Segregation ◽  
Wild Type ◽  
Chromatin Compaction ◽  
Meiotic Chromosomes ◽  
Sister Chromatids ◽  
Chromatid Cohesion ◽  
Meiotic Nondisjunction ◽  
Males And Females ◽  
Mitosis And Meiosis

Cohesion between sister chromatids is a prerequisite for accurate chromosome segregation during mitosis and meiosis. To allow chromosome condensation during prophase, the connections that hold sister chromatids together must be maintained but still permit extensive chromatin compaction. In Drosophila, null mutations in the orientation disruptor (ord) gene lead to meiotic nondisjunction in males and females because cohesion is absent by the time that sister kinetochores make stable microtubule attachments. We provide evidence that ORD is concentrated within the extrachromosomal domains of the nuclei ofDrosophila primary spermatocytes during early G2, but accumulates on the meiotic chromosomes by mid to late G2. Moreover, using fluorescence in situ hybridization to monitor cohesion directly, we show that cohesion defects first become detectable inord null spermatocytes shortly after the time when wild-type ORD associates with the chromosomes. After condensation, ORD remains bound at the centromeres of wild-type spermatocytes and persists there until centromeric cohesion is released during anaphase II. Our results suggest that association of ORD with meiotic chromosomes during mid to late G2 is required to maintain sister-chromatid cohesion during prophase condensation and that retention of ORD at the centromeres after condensation ensures the maintenance of centromeric cohesion until anaphase II.

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