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151.
Tumour necrosis factor-alpha up-regulates the expression of BMP-4 mRNA but inhibits chondrogenesis in mouse clonal chondrogenic EC cells, ATDC5 总被引:3,自引:0,他引:3
Tumour necrosis factor (TNF)-alpha causes the degradation of articular cartilage in arthritis via direct actions on chondrocytes. However, it remains unknown whether TNF-alpha affects chondrogenesis in chondroprogenitors. In the present study, we assessed the effects of TNF-alpha in vitro on chondrogenesis using mouse clonal chondrogenic EC cells, ATDC5. TNF-alpha (10 ng/ml) stimulated [3H] thymidine incorporation in undifferentiated ATDC5 cells, and suppressed cartilaginous nodule formation and the accumulation of cartilage-specific proteoglycan. We recently showed that undifferentiated ATDC5 cells express BMP-4 and that exogenously administered BMP-4 promotes chondrogenesis in these cells. Interestingly, TNF-alpha up-regulated the expression of BMP-4 mRNA in undifferentiated ATDC5 cells in time- and dose-dependent manners. However, exogenously administered BMP-4 was not capable of reversing the inhibitory action of TNF-alpha on chondrogenesis in ATDC5 cells. These results indicate that TNF-alpha stimulates both cell proliferation and BMP-4 expression but inhibits chondrogenesis in chondroprogenitor-like ATDC5 cells. 相似文献
152.
Two models have been proposed to describe the folding pathways of proteins. The framework model assumes the initial formation of the secondary structures whereas the hydrophobic collapse model supposes their formation after the collapse of backbone structures. To differentiate between these models for real proteins, we have developed a novel CD spectrometer that enables us to observe the submillisecond time frame of protein folding and have characterized the timing of secondary structure formation in the folding process of cytochrome c (cyt c). We found that approximately 20% of the native helical content was organized in the first phase of folding, which is completed within milliseconds. Furthermore, we suggest the presence of a second intermediate, which has alpha-helical content resembling that of the molten globule state. Our results indicate that many of the alpha-helices are organized after collapse in the folding mechanism of cyt c. 相似文献
153.
Polypeptide binding of Escherichia coli FtsH (HflB) 总被引:3,自引:0,他引:3
Yoshinori Akiyama Michael Ehrmann Akio Kihara & Koreaki Ito 《Molecular microbiology》1998,28(4):803-812
The Escherichia coli FtsH protein is a membrane-bound and ATP-dependent protease. In this study, we describe ATP-dependent conformational changes in FtsH as well as a polypeptide binding ability of this protein. A 33 kDa segment of FtsH became trypsin resistant in the presence of ATP. ATP and ATPγS prevented self-aggregation of detergent-solubilized FtsH-His6 -Myc at 37°C, again suggesting that the binding of ATP induces a conformational change in FtsH. Affinity chromatography showed that FtsH-His6 -Myc can associate with denatured alkaline phosphatase (PhoA) but not with the native enzyme. Denatured PhoA also prevented the aggregation of FtsH, and these two proteins co-sedimented through a sucrose gradient. Binding between FtsH-His6 -Myc and detergent-solubilized SecY was also demonstrated. Although FtsH-bound SecY was processed further for ATP-dependent proteolysis, FtsH-bound PhoA was not. Thus, FtsH association with denatured PhoA is uncoupled from proteolysis. Overproduction of FtsH significantly increased the cytoplasmic localization of the PhoA moiety of a MalF–PhoA hybrid protein, in which a charged residue had been introduced into a transmembrane segment. Thus, denatured PhoA binding of FtsH may also occur in vivo . 相似文献
154.
155.
Kanako Shimizu Jun Shinga Satoru Yamasaki Masami Kawamura Jan D?rrie Niels Schaft Yusuke Sato Tomonori Iyoda Shin-ichiro Fujii 《PloS one》2015,10(6)
Cell-based therapies using genetically engineered lymphocytes expressing antigen-specific T cell receptors (TCRs) hold promise for the treatment of several types of cancers. Almost all studies using this modality have focused on transfer of TCR from CD8 cytotoxic T lymphocytes (CTLs). The transfer of TCR from innate lymphocytes to other lymphocytes has not been studied. In the current study, innate and adaptive lymphocytes were transfected with the human NKT cell-derived TCRα and β chain mRNA (the Vα24 and Vβ11 TCR chains). When primary T cells transfected with NKT cell-derived TCR were subsequently stimulated with the NKT ligand, α-galactosylceramide (α-GalCer), they secreted IFN-γ in a ligand-specific manner. Furthermore when γδT cells were transfected with NKT cell-derived TCR mRNA, they demonstrated enhanced proliferation, IFN-γ production and antitumor effects after α-GalCer stimulation as compared to parental γδT cells. Importantly, NKT cell TCR-transfected γδT cells responded to both NKT cell and γδT cell ligands, rendering them bi-potential innate lymphocytes. Because NKT cell receptors are unique and universal invariant receptors in humans, the TCR chains do not yield mispaired receptors with endogenous TCR α and β chains after the transfection. The transfection of NKT cell TCR has the potential to be a new approach to tumor immunotherapy in patients with various types of cancer. 相似文献
156.
Joji Tokugawa Narisumi Cho Hiroharu Suzuki Natsuki Sugiyama Osamu Akiyama Yasuaki Nakao Takuji Yamamoto 《PloS one》2015,10(6)
Purpose
To investigate the length variation of the posterior auricular artery and propose a novel classification of the posterior auricular artery based on angiographical appearance.Patients and Methods
A series of 234 consecutive patients who had undergone conventional cerebral angiography was analyzed. The posterior auricular artery was examined on the lateral projection of the external carotid or common carotid arteriography. The posterior auricular artery was classified into four groups by length, using the external auditory canal and the top of the helix as radiographical landmarks. Our proposed classification is as follows: Type A, posterior auricular artery terminates between its origin and the center of the external auditory canal; Type B, posterior auricular artery terminates between the center of the external auditory canal and the top of the helix; Type C, posterior auricular artery terminates between the top of the helix and the vertex; and Type D, posterior auricular artery reaches up to the vertex.Results
A total of 424 (right, 214; left, 210) posterior auricular arteries were analyzed in 111 men and 123 women aged 11 to 91 years (mean, 61.0 years) examined for aneurysms in 78 cases, occlusive vascular diseases in 56, intracranial hemorrhages in 41, tumors in 35, and others in 24. Types A, B, C, and D were found in 15.1%, 34.9%, 48.8%, and 1.2% of the patients, respectively.Conclusion
A novel classification of the posterior auricular artery identifies four types based on its length on cerebral angiography. 相似文献157.
Hiroshi Takaichi Diego Comparini Junichiro Iwase Fran?ois Bouteau Stefano Mancuso Tomonori Kawano 《Plant signaling & behavior》2015,10(11)
Impact of transition metals which catalyze the generation of reactive oxygen species (ROS), on activation of cell death signaling in plant cells have been documented to date. Similarly in green paramecia (Paramecium bursaria), an aquatic protozoan species harboring symbiotic green algae in the cytoplasm, toxicities of various metallic ions have been documented. We have recently examined the effects of double-stranded GC-rich DNA fragments with copper-binding nature and ROS removal catalytic activity as novel plant cell-protecting agents, using the suspension-cultured tobacco cells. Here, we show that above DNA oligomers protect the cells of green paramecia from copper-induced cell death, suggesting that the phenomenon firstly observed in tobacco cells is not limited only within higher plants but it could be universally observable in wider range of organisms. 相似文献
158.
Aki Isobe Kenjiro Sawada Yasuto Kinose Chifumi Ohyagi-Hara Erika Nakatsuka Hiroshi Makino Tomonori Ogura Tomoko Mizuno Noriko Suzuki Eiichi Morii Koji Nakamura Ikuko Sawada Aska Toda Kae Hashimoto Seiji Mabuchi Tsuyoshi Ohta Ken-ichirou Morishige Hirohisa Kurachi Tadashi Kimura 《PloS one》2015,10(2)
Ovarian cancer remains the most lethal gynecologic cancer and new targeted molecular therapies against this miserable disease continue to be challenging. In this study, we analyzed the expressional patterns of Interleukin-6 (IL-6) and its receptor (IL-6R) expression in ovarian cancer tissues, evaluated the impact of these expressions on clinical outcomes of patients, and found that a high-level of IL-6R expression but not IL-6 expression in cancer cells is an independent prognostic factor. In in vitro analyses using ovarian cell lines, while six (RMUG-S, RMG-1, OVISE, A2780, SKOV3ip1 and OVCAR-3) of seven overexpressed IL-6R compared with a primary normal ovarian surface epithelium, only two (RMG-1, OVISE) of seven cell lines overexpressed IL-6, suggesting that IL-6/IL-6R signaling exerts in a paracrine manner in certain types of ovarian cancer cells. Ovarian cancer ascites were collected from patients, and we found that primary CD11b+CD14+ cells, which were predominantly M2-polarized macrophages, are the major source of IL-6 production in an ovarian cancer microenvironment. When CD11b+CD14+ cells were co-cultured with cancer cells, both the invasion and the proliferation of cancer cells were robustly promoted and these promotions were almost completely inhibited by pretreatment with anti-IL-6R antibody (tocilizumab). The data presented herein suggest a rationale for anti-IL-6/IL-6R therapy to suppress the peritoneal spread of ovarian cancer, and represent evidence of the therapeutic potential of anti-IL-6R therapy for ovarian cancer treatment. 相似文献
159.
Ryosuke Tateishi Nobuko Akiyama Maki Miyauchi Riko Yoshinaga Hiroki Sasanuma Takashi Kudo Miki Shimbo Masahiro Shinohara Koji Obata Jun-ichiro Inoue Masaki Shirakawa Dai Shiba Hiroshi Asahara Nobuaki Yoshida Satoru Takahashi Hironobu Morita Taishin Akiyama 《PloS one》2015,10(10)
Gravity change affects many immunological systems. We investigated the effects of hypergravity (2G) on murine thymic cells. Exposure of mice to 2G for three days reduced the frequency of CD4+CD8+ thymocytes (DP) and mature medullary thymic epithelial cells (mTECs), accompanied by an increment of keratin-5 and keratin-8 double-positive (K5+K8+) TECs that reportedly contain TEC progenitors. Whereas the reduction of DP was recovered by a 14-day exposure to 2G, the reduction of mature mTECs and the increment of K5+K8+ TEC persisted. Interestingly, a surgical lesion of the inner ear’s vestibular apparatus inhibited these hypergravity effects. Quantitative PCR analysis revealed that the gene expression of Aire and RANK that are critical for mTEC function and development were up-regulated by the 3-day exposure and subsequently down-regulated by the 14-day exposure to 2G. Unexpectedly, this dynamic change in mTEC gene expression was independent of the vestibular apparatus. Overall, data suggest that 2G causes a temporary reduction of DP and a persistent reduction of mature mTECs in a vestibular system-dependent manner, and also dysregulates mTEC gene expression without involving the vestibular system. These data might provide insight on the impact of gravity change on thymic functions during spaceflight and living. 相似文献
160.
The physical habitat characteristics associated with spatial distribution patterns of the freshwater mussel Pronodularia japanensis, which is used for oviposition by the Tokyo bitterling Tanakia tanago, were investigated in a small stream within a Tokyo bitterling protected area. The distribution of the mussels was found to be in an under-dispersed, non-random spatial pattern. Mussel occurrence correlated negatively with sediment softness, and positively with flow velocity, while mussel abundance was associated negatively with sediment softness and positively with sediment type (particle size). Furthermore, mussels were scarce in riverbed areas with a lack of sediment. These correlations suggest that the population dynamics of mussels and Tokyo bitterling may be influenced by changes in stream sediment conditions. To conserve the symbiosis between Tokyo bitterlings and mussels, a suitable benthic environment is required. 相似文献