A role for the PI3K/Akt/mTOR pathway in cardiac hypertrophy has been well documented. We reported that NFκB activation is needed for cardiac hypertrophy in vivo. To investigate whether both NFκB activation and PI3K/Akt/mTOR signaling participate in the development of cardiac hypertrophy, two models of cardiac hypertrophy, namely, induction in caAkt-transgenic mice and by aortic banding in mice, were employed. Rapamycin (2 mg/kg/daily), an inhibitor of the mammalian target of rapamycin, and the antioxidant pyrrolidine dithiocarbamate (PDTC; 120 mg/kg/daily), which can inhibit NFκB activation, were administered to caAkt mice at 8 weeks of age for 2 weeks. Both rapamycin and PDTC were also administered to the mice immediately after aortic banding for 2 weeks. Administration of either rapamycin or PDTC separately or together to caAkt mice reduced the ratio of heart weight/body weight by 21.54, 32.68, and 42.07% compared with untreated caAkt mice. PDTC administration significantly reduced cardiac NFκB activation by 46.67% and rapamycin significantly decreased the levels of p70S6K by 34.20% compared with untreated caAkt mice. Similar results were observed in aortic-banding-induced cardiac hypertrophy in mice. Our results suggest that both NFκB activation and the PI3K/Akt signaling pathway participate in the development of cardiac hypertrophy in vivo.

Objective: We have previously demonstrated that nuclear factor kappa B (NFκB) activation is needed for the development of cardiac hypertrophy in vivo. NFκB is a downstream transcription factor in the Toll-like receptor (TLR)-mediated signaling pathway; therefore, we investigated a role of TLR4 in cardiac hypertrophy in vivo. Methods: TLR4-deficient mice (C.C3H-Tlr4 lps-d, n = 6), wild-type (WT) genetic background mice (BALB/c, n = 6), TLR4-deleted strain (C57BL/10ScCr, n = 8), and WT controls (C57BL/10ScSn, n = 8) were subjected to aortic banding for 2 weeks. Age-matched surgically operated mice served as controls. In a separate experiment, rapamycin (2 mg/kg, daily) was administered to TLR4-deficient mice and WT mice immediately following aortic banding. The ratio of heart weight/body weight (HW / BW) was calculated, and cardiac myocyte size was examined by FITC-labeled wheat germ agglutinin staining of membranes. NFκB binding activity and the levels of phospho-p70S6K in the myocardium were also examined. Results: Aortic banding significantly increased the ratio of HW / BW by 33.9% (0.601 ± 0.026 vs. 0.449 ± 0.004) and cell size by 68.4% in WT mice and by 10.00% (0.543 ± 0.011 vs. 0.495 ± 0.005) and by 11.8% in TLR4-deficient mice, respectively, compared with respective sham controls. NFκB binding activity and phospho-p70S6K levels were increased by 182.6% and 115.2% in aortic-banded WT mice and by 78.0% and 162.0% in aortic-banded TLR4-deficient mice compared with respective sham controls. In rapamycin-treated aortic-banded mice, the ratio of HW / BW was increased by 18.0% in WT mice and by 3.5% in TLR4-deficient mice compared with respective sham controls. Conclusion: Our results demonstrate that TLR4 is a novel receptor contributing to the development of cardiac hypertrophy in vivo and that both the TLR4-mediated pathway and PI3K/Akt/mTOR signaling are involved in the development of cardiac hypertrophy in vivo.

Angiopoietin-1 (Ang-1) is essential for the maturation of blood vessels during vasculogenesis. Besides angiogenesis, recent publications indicate that Ang-1 is also a potent survival factor for endothelial cells; however, the mechanisms by which pathways remain elusive. Doxorubicin (DOX) is a powerful anticancer drug, but its use is severely restricted by its cardiotoxicity. The authors report here that Ang-1 inhibits DOX-induced cell death in human umbilical vein endothelial cells (HUVECs). Interestingly, the DOX-induced up-regulation in Fas (CD95/APO-1) and Fas ligand expression could be blocked by Ang-1, indicating a pivotal role of Ang-1 in DOX-induced Fas and Fas ligand expression. In addition, the prevention of cell death in this model system seems to be dependent on the activation of phosphatidylinositol 3-kinase (PI3K)/Akt, as Ang-1 fails to inhibit DOX-induced cell death while PI3K/Akt pathway was blocked by the PI3K inhibitor LY294002. Moreover, Ang-1 inhibits DOX-induced up-regulation of p53 through PI3K/Akt. Therefore, Ang-1 is a potent inhibitor for DOX-induced cell death through Fas and PI3K/Akt-mediated pathways.

Cancer metastasis is a highly complex process and is of great clinical importance since majority of cancer related mortality is associated with metastatic disease rather than primary tumor. The fact that cancer metastasis can develop years or even decades after primary tumor diagnosis, makes this process even more complex and therefore its understanding is of vital importance. Cervical cancer (CxC) is one of the most commonly diagnosed and cause of death among gynecologic cancers worldwide. In this chapter, our aim is to provide a broad overview of risk factors, modes of metastasis and major molecular factors and signaling pathways involved in the progression and metastasis of CxC. The understanding of these factors will enhance the knowledge of CxC pathogenesis and targeting these pathways would help combat against CxC and its metastasis.

The phosphoinositide 3-kinases (PI3K/Akt) dependent signaling pathway plays an important role in cardiac function, specifically cardiac contractility. We have reported that sepsis decreases myocardial Akt activation, which correlates with cardiac dysfunction in sepsis. We also reported that preventing sepsis induced changes in myocardial Akt activation ameliorates cardiovascular dysfunction. In this study we investigated the role of PI3K/Akt on cardiomyocyte function by examining the role of PI3K/Akt-dependent signaling on [Ca 2+]i, Ca2+ transients and membrane Ca2+ current, ICa, in cultured murine HL-1 cardiomyocytes. LY294002 (120 μM), a specific PI3K inhibitor, dramatically decreased HL-1 [Ca 2+]i, Ca2+ transients and ICa. We also examined the effect of PI3K isoform specific inhibitors, i.e. α (PI3-kinase α inhibitor 2; 28 nM); ? (TGX-221; 100 nM) and γ (AS-252424; 100 nM), to determine the contribution of specific isoforms to HL-1 [Ca 2+]i regulation. Pharmacologic inhibition of each of the individual PI3K isoforms significantly decreased [Ca2+]i, and inhibited Ca 2+ transients. Triciribine (120 μM), which inhibits AKT downstream of the PI3K pathway, also inhibited [Ca2+]i, and Ca 2+ transients and ICa. We conclude that the PI3K/Akt pathway is required for normal maintenance of [Ca2+]i in HL-1 cardiomyocytes. Thus, myocardial PI3K/Akt-PKB signaling sustains [Ca 2+]i required for excitation-contraction coupling in cardiomyoctyes.

Förskollärares syn på utomhusmiljön kan påverkas av flera aspekter. Tidigare forskning inom området samt vårt egna intresse har gett oss motiv till att skapa förståelse för hur förskollärare uppfattar barns lärande i utomhusmiljön.  Syftet med denna studie var  att genom det utvecklingspedagogiska perspektivet undersöka förskollärares syn på utomhusmiljön och dess betydelse för barns lärande. Utifrån vår metod och det teoretiska perspektiv som denna studie baserats på  klassas detta som en kvalitativ studie. I genomförandet av vår studien deltog sex stycken förskollärare från kommunala förskolor i norra Sverige. I vårt resultat framkommer det att förskollärarna anser att utomhusmiljön har betydelse för barns lärande. Förskollärarna anser att deras roll för att främja barns lärande innefattar att inta en aktiv roll som innebär att stötta, vara lyhörd samt medforskande tillsammans med barnen. Diskussionen  lyfter de väsentliga delarna ur resultatet som  innebär att synen på utomhusmiljön kan vara avgörande för hur förskollärare väljer att använda den. Om utomhusmiljön ses som ett komplement till inomhusmiljön kan förutsättningarna för barns lärande vidgas. De slutsatser som har framkommit är att förskolans utomhusmiljö kan vara komplex, eftersom att det är många olika faktorer som förskollärarna bör ta hänsyn till vilket påverkar hur förskollärare ser på lärandet i utomhusmiljön. / <p>2019-12-20</p>

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20991号 / 医博第4337号 / 新制||医||1027(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 小川 誠司, 教授 野田 亮, 教授 江藤 浩之 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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As the primary antagonist to the tumorigenic PI3K/AKT pathway, PTEN is classified as a tumor suppressor. The inactivation of PTEN through genetic or post-translational modifications is a critical step in the tumorigenesis of many breast cancers (BCs). SIPL1 is a novel protein which was identified as a PTEN negative regulator. To further explore SIPL1-mediated PTEN inactivation, we analyzed 17 datasets covering 3484 BC cases and 228 normal individuals. SIPL1 gene amplification and increased mRNA expression correlates with the progression and poor prognosis of ER and/or PR positive tumors. Furthermore, examination of a BC tissue microarray containing 224 tumor cases revealed elevated SIPL1 protein expression in ER+ and PR+ tumors and was associated with greater AKT activation. Additionally, ectopic expression of SIPL1 in CHO-K1 cells resulted in increased AKT activation and cell proliferation, and cytoskeleton reorganization alongside with PTEN downregulation. SIPL1 contributes to the linear polyubiquitination of NEMO, suggesting a role for SIPL1 in PTEN ubiquitination. Indeed, it was SIPL1, not the SIPL1-∆UBL (a PTEN-binding defective mutant) which robustly induced PTEN polyubiquitination in a lysine (K) 63-dependent but K48-independent manner. While K48-linked polyubiquitin chains direct protein degradation, K63-linked chains regulate a variety of protein functions. SIPL1 binds polyubiquitinated PTEN with significantly higher affinity than non-ubiquitinated PTEN. A SIPL1 mutant, SIPL1-TFLV, is unable to cause PTEN ubiquitination but is capable of PTEN association. Collectively, our results reveal that SIPL1 interacts with PTEN with a low affinity, which results in PTEN polyubiquitination, and that the modification may stabilize the association between SIPL1 and PTEN. We propose a model where SIPL1 mediates the K63-linked ubiquitination of PTEN inactivating it. The downregulation of PTEN, when paired with the tumor-promoting effects of ER and/or PR, stimulates breast tumorigenesis. SIPL1 is an important BC marker and future research should focus on its potential as a therapeutic target. / Thesis / Doctor of Philosophy (PhD)