191 research outputs found

    Nanoparticles prepared from the water extract of Gusuibu (Drynaria fortunei J. Sm.) protects osteoblasts against insults and promotes cell maturation

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    Our previous study showed that Gusuibu (Drynaria fortunei J. Sm.) can stimulate osteoblast maturation. This study was further designed to evaluate the effects of nanoparticles prepared from the water extract of Gusuibu (WEG) on osteoblast survival and maturation. Primary osteoblasts were exposed to 1, 10, 100, and 1000 μg/mL nanoparticles of WEG (nWEG) for 24, 48, and 72 hours did not affect morphologies, viability, or apoptosis of osteoblasts. In comparison, treatment of osteoblasts with 1000 μg/mL WEG for 72 hours decreased cell viability and induced DNA fragmentation and cell apoptosis. nWEG had better antioxidant bioactivity in protecting osteoblasts from oxidative and nitrosative stress-induced apoptosis than WEG. In addition, nWEG stimulated greater osteoblast maturation than did WEG. Therefore, this study shows that WEG nanoparticles are safer to primary osteoblasts than are normal-sized products, and may promote better bone healing by protecting osteoblasts from apoptotic insults, and by promoting osteogenic maturation

    Chlorin e6 Prevents ADP-Induced Platelet Aggregation by Decreasing PI3K-Akt Phosphorylation and Promoting cAMP Production

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    A number of reagents that prevent thrombosis have been developed but were found to have serious side effects. Therefore, we sought to identify complementary and alternative medicinal materials that are safe and have long-term efficacy. In the present studies, we have assessed the ability of chlorine e6 (CE6) to inhibit ADP-induced aggregation of rat platelets and elucidated the underlying mechanism. CE6 inhibited platelet aggregation induced by 10 µM ADP in a concentration-dependent manner and decreased intracellular calcium mobilization and granule secretion (i.e., ATP and serotonin release). Western blotting revealed that CE6 strongly inhibited the phosphorylations of PI3K, Akt, c-Jun N-terminal kinase (JNK), and different mitogen-activated protein kinases (MAPKs) including extracellular signal-regulated kinase 1/2 (ERK1/2) as well as p38-MAPK. Our study also demonstrated that CE6 significantly elevated intracellular cAMP levels and decreased thromboxane A2 formation in a concentration-dependent manner. Furthermore, we determined that CE6 initiated the activation of PKA, an effector of cAMP. Taken together, our findings indicate that CE6 may inhibit ADP-induced platelet activation by elevating cAMP levels and suppressing PI3K/Akt activity. Finally, these results suggest that CE6 could be developed as therapeutic agent that helps prevent thrombosis and ischemia

    Disrupted interferon-related molecular networks and the over-expressed Ifnar1 in the brain of adult Ts1Cje mouse model of Down syndrome

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    Down syndrome (DS) is a chromosomal disorder resulting from trisomy of human chromosome 21 (HSA21) and all DS individual exhibit cognitive impairment. Ts1Cje mouse model of DS has a triplicated region of mouse chromosome 16 (MMU16) which is homologous to HSA21. Three interferon receptor genes (Ifnar1, Ifnar2 and Ifngr2) are located at the triplicated region in MMU16 and also in HSA21. In this study, we aimed to determine the disrupted molecular networks and the role of the candidate gene in the neurogenic-to-gliogenic shift of Ts1Cje mouse brain. A functional transcriptome analysis was performed on the cerebral cortex, cerebellum and hippocampus of Ts1Cje mice at 4 time-points: postnatal day (P)1, P15, P30 and P84. Functional clustering analysis of the identified 317 differentially expressed genes reported interferon-related signalling networks as the most significantly dysregulated pathway in Ts1Cje postnatal brain. Both Ifnar1 and Stat1 were found over-expressed in P84 Ts1Cje cerebral cortex and cerebellum when compared to wild type littermates through qRT-PCR and western blotting analysis. Subsequently, the role of triplicated Ifnar1 was determined by treating Ifnar1 antagonist on differentiating neural stem cells derived from the SVZ of adult Ts1Cje. The assessment on the antagonistic effect of Ifnar1 antagonist reported successful attenuation on the aberrant Stat1 expression in the Ts1Cje group to an expression level which was similar to the wild type group

    Overexpression of interferon alpha or beta receptors in the brain of adult Ts1Cje mouse model of Down syndrome

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    Introduction: Down syndrome (DS) is a generic disorder with trisomy of human chromosome 21 (HSA21) and all DS patients exhibited intellectual disability. Ts1Cje mouse model of DS has partial triplication of mouse chromosome 16 (MMU16) which is homologous to HSA21. The JAK (Janus kinase) and STAT (signal transducer and activator of transcription) signalling pathway is involved in neurogenesis and gliogenesis regulation. Cytokines especially the interferons (IFN) family is the major activator of JAK-STAT signalling pathway. Furthermore, interferon receptor genes (Ifnar), Ifnar2 and Ifngr2 are located at the triplicated region in MMU16 and also in HSA21. Method: Gene expression of Ifnar1, Ifnar2, Ifngr2 and associated genes in JAK-STAT signalling pathway (Jak1, Jak2, Stat1, Stat3 and Stat6) in the cerebral cortex and cerebellum between Ts1Cje and wild type control at four time-points; post natal day (P)1, P15, P30 and P84 was investigated by using qRT-PCR techniques. Western blotting was used to confirm the overexpression of Ifnar1, Ifnar2 and Stat1 in the cerebral cortex and cerebellum of Ts1Cje aged P84. Results: Ifnar1, Ifnar2, Ifngr2 and Stat1 were significantly overexpression in the cerebral cortex and cerebellum of Ts1Cje at various time points as compared to control littermates. Protein expression analysis confirmed the overexpression of Ifnar1 and Stat1 in the cerebellum of Ts1Cje mouse at P84 as compared to wild type. The findings suggest that overexpression of interferon receptors will increase sensitivity towards interferon levels in Ts1Cje mouse brain. Consequently, the over-stimulated JAK-STAT signalling pathway may contribute to the defective neurogenesis the Down syndrome mouse brain

    Statistical identification of gene association by CID in application of constructing ER regulatory network

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    <p>Abstract</p> <p>Background</p> <p>A variety of high-throughput techniques are now available for constructing comprehensive gene regulatory networks in systems biology. In this study, we report a new statistical approach for facilitating <it>in silico </it>inference of regulatory network structure. The new measure of association, coefficient of intrinsic dependence (CID), is model-free and can be applied to both continuous and categorical distributions. When given two variables X and Y, CID answers whether Y is dependent on X by examining the conditional distribution of Y given X. In this paper, we apply CID to analyze the regulatory relationships between transcription factors (TFs) (X) and their downstream genes (Y) based on clinical data. More specifically, we use estrogen receptor α (ERα) as the variable X, and the analyses are based on 48 clinical breast cancer gene expression arrays (48A).</p> <p>Results</p> <p>The analytical utility of CID was evaluated in comparison with four commonly used statistical methods, Galton-Pearson's correlation coefficient (GPCC), Student's <it>t</it>-test (STT), coefficient of determination (CoD), and mutual information (MI). When being compared to GPCC, CoD, and MI, CID reveals its preferential ability to discover the regulatory association where distribution of the mRNA expression levels on X and Y does not fit linear models. On the other hand, when CID is used to measure the association of a continuous variable (Y) against a discrete variable (X), it shows similar performance as compared to STT, and appears to outperform CoD and MI. In addition, this study established a two-layer transcriptional regulatory network to exemplify the usage of CID, in combination with GPCC, in deciphering gene networks based on gene expression profiles from patient arrays.</p> <p>Conclusion</p> <p>CID is shown to provide useful information for identifying associations between genes and transcription factors of interest in patient arrays. When coupled with the relationships detected by GPCC, the association predicted by CID are applicable to the construction of transcriptional regulatory networks. This study shows how information from different data sources and learning algorithms can be integrated to investigate whether relevant regulatory mechanisms identified in cell models can also be partially re-identified in clinical samples of breast cancers.</p> <p>Availability</p> <p>the implementation of CID in R codes can be freely downloaded from <url>http://homepage.ntu.edu.tw/~lyliu/BC/</url>.</p

    Janus monolayers of transition metal dichalcogenides.

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    Structural symmetry-breaking plays a crucial role in determining the electronic band structures of two-dimensional materials. Tremendous efforts have been devoted to breaking the in-plane symmetry of graphene with electric fields on AB-stacked bilayers or stacked van der Waals heterostructures. In contrast, transition metal dichalcogenide monolayers are semiconductors with intrinsic in-plane asymmetry, leading to direct electronic bandgaps, distinctive optical properties and great potential in optoelectronics. Apart from their in-plane inversion asymmetry, an additional degree of freedom allowing spin manipulation can be induced by breaking the out-of-plane mirror symmetry with external electric fields or, as theoretically proposed, with an asymmetric out-of-plane structural configuration. Here, we report a synthetic strategy to grow Janus monolayers of transition metal dichalcogenides breaking the out-of-plane structural symmetry. In particular, based on a MoS2 monolayer, we fully replace the top-layer S with Se atoms. We confirm the Janus structure of MoSSe directly by means of scanning transmission electron microscopy and energy-dependent X-ray photoelectron spectroscopy, and prove the existence of vertical dipoles by second harmonic generation and piezoresponse force microscopy measurements
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