No description available.

No description available.

No description available.

京都大学 / 新制・論文博士 / 博士(医学) / 乙第13514号 / 論医博第2264号 / 新制||医||1061(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 萩原 正敏, 教授 湊谷 謙司, 教授 中島 貴子 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

No description available.

No description available.

No description available.

The mammalian hippocampus is responsible for many crucial brain functions such as learning, memory, and neurogenesis in adults. Its degeneration is a pathology associated with the early stages of Alzheimer’s disease. A variety of genes have been associated with both neuroprotection and neurogenesis in the brain, some of which include progesterone membrane component 1 (Pgrmc1) and kit ligand (KitL). Pgrmc1 is recognized for mediating hormonal functions in both the ovary and neuroendocrine regions such as the anteroventral periventricular nucleus (AVPV), but its functions in the hippocampus are not well known. Both Pgrmc1 and KitL share downstream targets, the most strongly supported being genes in the Janus kinase (Jak)/signal transducer and activator of transcription (Stat) pathway. I hypothesized that Pgrmc1 regulates neural targets through KitL/c-Kit signaling. To investigate this hypothesis I used a variety of in vivo and in vitro techniques. These techniques included mapping both KitL and receptor c-Kit in the adult female rat brain using in situ hybridization. I used Pgrmc1 silencing with siRNA in hippocampal-derived mHe-18 cells and Pgrmc1/2 double conditional knock out mouse brains to study Pgrmc1 regulation of KitL synthesis. To determine common downstream targets of KitL and Pgrmc1 I then treated mHe-18 cells with soluble KitL protein. Finally, to determine whether c-Kit mediated effects of Pgrmc1, I treated cells with both Pgrmc1 siRNA and AG-1296, a c-Kit inhibitor. The results show that Pgrmc1 regulates KitL expression, as well as downstream targets Pias1, 2, 3, and 4. However, AG-1296 did not abrogate Pgrmc1 regulation of the downstream targets, demonstrating regulation independent of KitL signaling. Taken together, these results suggest that while Pgrmc1 alters KitL expression and regulates the same genes as KitL/c-Kit, the mechanism of action likely differs. Considering that these two genes are involved in neurogenesis and neuroprotection, as well as memory and learning, a better understanding of the pathways may help lead the way in treating neurodegenerative diseases in the future.

The anteroventral periventricular (AVPV) nucleus of the hypothalamus integrates estradiol (E2) and progesterone (P4) feedback signals from the ovaries to stimulate gonadotropin releasing hormone (GnRH) neurons and trigger an ovulatory surge in luteinizing hormone (LH). E2 maintains the daily cyclic LH surge and P4 quickly amplifies the surge and limits it to one day. P4 amplification of the surge and rapid signaling in the AVPV may occur through its non-classical progestin receptors. Previous in vitro studies using a microarray analysis with N42 mouse embryonic hypothalamic neurons suggest that progesterone membrane component 1 (Pgrmc1) regulates genes linked to the janus kinase (Jak)/signal transducer and activator of transcription (Stat) signaling pathway. I hypothesized that P4 alters Jak/Stats through Pgrmc1 regulation of one or more Jak or Stat molecules and then performed a set of in vitro and in vivo studies to test this. I transfected N42 cells with either scramble or Pgrmc1 siRNA followed by treatment with either ethanol vehicle control or 10 nM P4 and measured Jak1, Jak2, Stat3, Stat5a, Stat5b, and Stat6 mRNA levels via quantitative polymerase chain reaction (QPCR). Jak1 and Jak2 mRNAs increased with P4 treatments, and this upregulation required Pgrmc1. Silencing Pgrmc1 in the cells also produced an increase in Jak1 and Jak2 mRNA, suggesting that Pgrmc1 constitutively suppressed jak1 and jak2 in the absence of P4. None of the Stats were significantly regulated by P4 or Pgrmc1 silencing. To determine how Pgrmc1 regulates Jak/Stat in vivo, I took AVPV microdissections from Pgrmc1 and Pgrmc2 double conditional knockout (DCKO) mice and looked at gene expression of jak/stat. Transcript levels of Jak2, but not Jak1, were severely downregulated in the DCKO animals and Stat mRNAs were not significantly changed. Discrepancies from in vitro and in vivo data prompted me to analyze the role of the class II progestin and adipoQ (Paqr) receptors in Jak/Stat signaling. P4 treatments and siRNA experiments in N42 cells showed that Paqr8, but not Paqr7, was required for P4 upregulation of Jak1 and Jak2 mRNAs. Overall, these findings show that Pgrmc1 regulates Jak1 and Jak2 synthesis in a P4-dependent and -independent manner that requires interaction with Paqr8.

Prostaglandin (PG) F₂α, is luteolytic in ewes, but the exact mechanism for this effect is not clear. 6α-Methyl-17α hydroxyprogesterone acetate (MPA) reduces uterine secretion of PGF₂α, but it does not interfere with luteolysis. The mechanism by which MPA suppresses PGF₂α and permits luteal regression remains to be determined. Three experiments were conducted to determine whether MPA reduces PGF₂α in uteroovarian blood, causes the release of PGF₂α before d 14 of the estrous cycle, or increases sensitivity of corpora lutea (CL) to exogenous PGF₂α. In Exp. 1 and 2, blank (control) or MPA-impregnated pessaries were inserted six days after estrus (i.e., d 6). Jugular, vena caval, and(or) uteroovarian blood samples were collected frequently (i.e., at .5 h intervals during twice daily collection periods of 2 h each) before and after luteolysis. The MPA reduced (P < .05) jugular, vena caval, and uteroovarian concentrations of PGF₂α, but MPA did not affect the interval from estrus to the first day of luteolysis. Average PGF₂α concentrations in uteroovarian and vena caval blood differed (P < .05) but the profiles did not. In Exp. 3, blank (control), MPA-impregnated, or no (untreated) pessaries were inserted on d 7. A minimal luteolytic dose of PGF₂α (Lutalyse ®; 4 mg/58 kg of body weight) was administered on d 8 or 12, blood samples were collected and the CL were collected 48 h after PGF₂α treatment. The MPA increased the sensitivity of CL to exogenous PGF₂α. Progesterone and CL weights were less (P < .05) in MPA-treated ewes than in control and untreated ewes given PGF₂α on d-8. The MPA-treated ewes given PGF₂α on d-12 had smaller CL than did ewes in the other two groups, but MPA did not affect progesterone concentrations. In summary, MPA reduces the ability of the uterus to secrete PGF 7a and increases the sensitivity of CL to a minimal luteolytic dose of PGF₂α. This information should improve our ability to control the estrous cycle ewes. / Master of Science