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101.
Hepatoblasts, hepatic stem/progenitor cells in liver development, have a high proliferative potential and the ability to differentiate into both hepatocytes and cholangiocytes. In regenerative medicine and drug screening for the treatment of severe liver diseases, human induced pluripotent stem (iPS) cell-derived mature functional hepatocytes are considered to be a potentially good cell source. However, induction of proliferation of these cells is difficult ex vivo. To circumvent this problem, we generated hepatic progenitor-like cells from human iPS cells using serial cytokine treatments in vitro. Highly proliferative hepatic progenitor-like cells were purified by fluorescence-activated cell sorting using antibodies against CD13 and CD133 that are known cell surface markers of hepatic stem/progenitor cells in fetal and adult mouse livers. When the purified CD13highCD133+ cells were cultured at a low density with feeder cells in the presence of suitable growth factors and signaling inhibitors (ALK inhibitor A-83-01 and ROCK inhibitor Y-27632), individual cells gave rise to relatively large colonies. These colonies consisted of two types of cells expressing hepatocytic marker genes (hepatocyte nuclear factor 4α and α-fetoprotein) and a cholangiocytic marker gene (cytokeratin 7), and continued to proliferate over long periods of time. In a spheroid formation assay, these cells were found to express genes required for mature liver function, such as cytochrome P450 enzymes, and secrete albumin. When these cells were cultured in a suitable extracellular matrix gel, they eventually formed a cholangiocytic cyst-like structure with epithelial polarity, suggesting that human iPS cell-derived hepatic progenitor-like cells have a bipotent differentiation ability. Collectively these data indicate that this novel procedure using an in vitro expansion system is useful for not only liver regeneration but also for the determination of molecular mechanisms that regulate liver development. 相似文献
102.
Ayaka Sakakura Martin Pauze Atsuhiro Namiki Hiroomi Tamura Kengo Hanaya 《Bioscience, biotechnology, and biochemistry》2019,83(2):185-191
Fatty acid monoesters of hydroxytyrosol [2-(3,4-dihydroxyphenyl)ethanol] were synthesized in two steps from tyrosol (4-hydroxyphenylethanol) by successive Candida antarctica lipase B-catalyzed chemoselective acylation on the primary aliphatic hydroxy group over phenolic hydroxy group in tyrosol, and 2-iodoxybenzoic acid (IBX)-mediated hydroxylation adjacent to the remaining free phenolic hydroxy group. Examination of their suppression effects on nitric oxide production stimulated by lipopolysaccharides in RAW264.7 cells showed that hydroxytyrosol butyrate exhibited the highest inhibition (IC50 7.0 μM) among the tested compounds. 相似文献
103.
Cambrian Series 3 lithistid sponge–microbial reefs in Shandong Province,North China: reef development after the disappearance of archaeocyaths 下载免费PDF全文
Natsuko Adachi Ayaka Kotani Yoichi Ezaki Jianbo Liu 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2015,48(3):405-416
The Cambrian Series 3 Zhangxia Formation in Shandong Province, North China, includes small‐scale lithistid sponge–microbial reefs. The lithistid sponges grew on oolitic and bioclastic sediments, which were stabilized by microbial activities. The relative abundances of microbial components (e.g. calcimicrobe Epiphyton and stromatolites) vary among the reefs. However, the microbial components commonly encrusted or bound the lithistid sponges, formed remarkable encrustations on the surfaces of the sponges. Epiphyton especially grew upward and downward. The lithistid sponges thus provided substrates for the attachment and development of microbes, and the microbes played essential roles as consolidators, by encrusting reef‐building sponges. Additionally, the lithistid sponges were prone to degradation via microbial activities and diagenetic processes, and were thus preserved as micritic bodies, showing faint spicular networks or abundant spicules. Such low preservation potential within the reef environment obscured the presence of the sponges and their widespread contribution as reef‐building organisms during the Cambrian. During the prolonged interval after the demise of archaeocyaths, purely microbial reefs, such as stromatolites and thrombolites have been considered to be the principal reef builders, in association with rare lithistid sponge–microbial associations. However, recent findings, including those from Shandong Province and Korea, suggest that the lithistid sponge‐bearing reefs were more extensive during the Epoch 3 to the Furongian than previously thought. These lithistid sponge–microbial reefs were precursors of the sponge–microbial reefs that dominated worldwide in the Early Ordovician. 相似文献
104.
A new flavanone and other flavonoids from green perilla leaf extract inhibit nitric oxide production in interleukin 1β-treated hepatocytes 总被引:1,自引:0,他引:1
Ayaka Nakajima Yuka Yamamoto Nao Yoshinaka Mayuri Namba Hirotaka Matsuo Tetsuya Okuyama 《Bioscience, biotechnology, and biochemistry》2013,77(1):138-146
A new flavanone, shisoflavanone A (1), and several flavonoids were purified from the ethyl acetate-soluble fraction of green perilla leaves (Perilla frutescens Britton var. crispa form viridis), and their structures were identified. Shisoflavanone A was elucidated as 8-hydroxy-6,7-dimethoxyflavanone based on its spectral data. Other constituents of the ethyl acetate-soluble fraction, i.e. 5,8-dihydroxy-7-methoxyflavanone (2), negletein (5,6-dihydroxy-7-methoxyflavone) (3), luteolin (4), apigenin (5), esculetin (6), and protocatechuic acid (7), were identified. This is the first time that constituents 2, 3, and 6 have been found in green perilla. Shisoflavanone A and the other constituents (except 7) significantly inhibited nitric oxide production in interleukin 1β-stimulated rat hepatocytes, which have been used to monitor the anti-inflammatory effects of herbal constituents. The present findings suggest that these constituents, including shisoflavanone A, may be involved in the anti-inflammatory effects of green perilla leaves. 相似文献
105.
Yasuhisa Araki Yuki Matsui Ayaka Iizumi Syoutarou Tsuchiya Yumi Kaneko Kazufumi Sato Tomoya Ozaki Yasuyuki Araki Mitsuru Nishimura 《Human cell》2016,29(4):176-180
Trophectoderm vesicles (TVs) are observed in some blastocysts that penetrate cells from the zona pellucida to the outer margin. Therefore, we compared this incidence in relation to hatching, pregnancy, and miscarriage rates between conventional in vitro fertilization (c-IVF) and intracytoplasmic sperm injection (ICSI). Vitrified/warmed blastocysts (n = 112) were derived from surplus embryos. The blastocysts were then observed using time-lapse cinematography to resolve the relationship between hatching and implantation. Another study was conducted that comprised 681 embryo transfer cycles in 533 patients who received a single vitrified/warmed blastocyst from our clinic. The incidence of TV was significantly higher in embryos inseminated by ICSI compared with c-IVF [ICSI: 51/56 (91 %); c-IVF: 25/56 (45 %); P < 0.01]. The successful hatching rate was significantly lower in ICSI than in c-IVF [ICSI: 11/56 (20 %); c-IVF: 29/56 (52 %); P < 0.01]. In addition, the hatching rate was significantly lower when TVs were present (14/76; 18 %) than in non-TV embryos (26/36; 72 %) (P < 0.01). In regard to the clinical study results, no significant differences were found between the groups in the pregnancy rate (TV present group: 107/183, 58.5 %; TV absent group: 273/498, 54.8 %) and miscarriage rate (TV present group: 21/107, 19.6 %; TV absent group: 53/273, 19.4 %). In vivo, we hypothesized that hatching and hatched would occur naturally by assisting protease action in the uterus; therefore, these results suggest that the presence of TV has no effect on pregnancy rates in the clinical setting. 相似文献
106.
Neuropeptides modulate human eosinophil chemotaxis. 总被引:5,自引:0,他引:5
To investigate the role of neuropeptides in allergic inflammation, we examined the effect of peptides on eosinophil chemotaxis. Eosinophils were purified from the blood of allergic and normal subjects using a discontinuous Percoll density gradients. Chemotaxis was induced by platelet-activating factor (PAF) and leukotriene B4, and was assayed by a modified Boyden's chamber technique. Four neuropeptides were examined in this study: substance P (SP), neurokinin A, calcitonin gene-related peptide (CGRP), and cholecystokinin octapeptide. Peptides alone (10 nM to 10 microM) were not chemotactic for eosinophils. However, when eosinophils were pre-treated with peptides (100 nM) at 37 degrees C for 30 min, chemotactic response to PAF (10 nM) was significantly enhanced (p < 0.01) in allergic subjects; % control by SP, neurokinin A, CGRP and cholecystokinin octapeptide was 269 +/- 42, 243 +/- 32, 227 +/- 21, and 251 +/- 42, respectively (n = 8). Similar results were obtained in leukotriene B4-induced eosinophil chemotaxis. In contrast, no enhancement was observed in normal subjects. Potentiating effect of SP and CGRP on PAF-induced eosinophil chemotaxis in allergic subjects was significantly attenuated by SP antagonist [D-Pro2,D-Trp7,9]-SP and human CGRP (8-37) receptor antagonist, respectively. Neutral endopeptidase inhibitors (phosphoramidon, leupeptin, and bestatin) failed to significantly augment the PAF-induced eosinophil chemotaxis when the cells were pretreated with various peptides and neutral endopeptidase inhibitors. The C-terminal fragment of SP (SP6-11) had an effect similar to that of the intact SP molecule, whereas no potentiating effect by the N-terminal of SP (SP1-9) was observed. These results suggest that neuropeptides may play a significant role in eosinophil infiltration by priming cells in allergic inflammation. 相似文献
107.
Bortezomib/PS-341/Velcade, a proteasome inhibitor, is widely used to treat multiple myeloma. While several mechanisms of the cytotoxicity of the drug were proposed, the actual mechanism remains elusive. We aimed to identify genes affecting the cytotoxicity of Bortezomib in the fission yeast S. pombe as the drug inhibits this organism's cell division cycle like proteasome mutants. Among the 2815 genes screened (covering 56% of total ORFs), 19 genes, whose deletions induce strong synthetic lethality with Bortezomib, were identified. The products of the 19 genes included four ubiquitin enzymes and one nuclear proteasome factor, and 13 of them are conserved in humans. Our results will provide useful information for understanding the actions of Bortezomib within cells. 相似文献
108.
Isobe Shiho Ota Ayaka Takata Shiori Hamajima Rina Makino Shizuka Kobayashi Jun Kobayashi Michihiro Ikeda Motoko 《Cytotechnology》2021,73(4):643-655
Cytotechnology - The cell line NISES-AnPe-428 (AnPe), derived from the Chinese oak silkworm Antheraea pernyi, was characterized for its permissiveness and productivity for six different... 相似文献
109.