Background Our previous study showed that the combined Chinese herbs containing scutellaria baicalensis georgi and gardenia jasminoids ellis inhibited atherosclerosis. In this study, we sought to determine if baicalin...Background Our previous study showed that the combined Chinese herbs containing scutellaria baicalensis georgi and gardenia jasminoids ellis inhibited atherosclerosis. In this study, we sought to determine if baicalin and geniposide could inhibit atherosclerosis through Wntl and dickkopf-related protein-1 （DKK1）. Methods The wild-type and ApoE-/- mice were treated with baicalin, geniposide, and baicalin plus geniposide daily by gavage for 12 weeks. Blood lipid levels were measured with an automatic biochemistry analyzer. Aortic atherosclerotic lesion areas were analyzed with Image-ProPlus software. The mRNA and protein expression of DKK1, Wntt and nuclear factor-r,B （NF-κB） were measured with RT-PCR and Westem Blot. Serum levels of interleukin-12 （IL-12） were quantified with ELISA. Results The baicalin or geniposide monotherapy as well as combination therapy inhibited the development of atherosclerotic lesions, increased Wntl and decreased DKKI expression and elevated the ratio of Wntl/DKK1 compared with high-lipid diet group. However, only baicalin or geniposide monotherapy decreased NF-κB expression. Moreover, baicalin and geniposide monoor combination therapy lowered IL-12 levels. Geniposide reduced both serum total cholesterol and low density lipoprotein levels, while baicalin either alone or in combination with geniposide did not affect serum lipid levels. In human, umbilical vein endothelial ceils stimulated by oxidized low density lipoprotein, baicalin and geniposide also increased Wntl and decreased DKK1 expression and elevated the ratio of Wntl/DKK1. Condusions Baicalin and geniposide exert inflammation-regulatory effects and may prevent atherosclerotic lesions through enhancing Wntl and inhibit- ing DKK1 expression.展开更多
The influence of internal noise on the calcium oscillations is studied. It is found that stochastic calcium oscillations occur when the internal noise is considered, while the corresponding deterministic dynamics only...The influence of internal noise on the calcium oscillations is studied. It is found that stochastic calcium oscillations occur when the internal noise is considered, while the corresponding deterministic dynamics only yields a steady state. Also,. the performance of such oscillations shows two maxima with the variation of the system size, indicating the occurrence of system size resonance. This behavior is found to be intimately connected with the canard phenomenon. Interestingly, it is also found that one of the optimal system sizes matches well with the real cell size, and such a match is robust to the variation of the control parameters.展开更多
Entosis, a ceU-in-ceU process, has been implicated in the formation of aneuploidy associated with an aberrant cell division control. Microtubule plus-end-tracking protein TI P150 facilitates the loading of MCAK onto t...Entosis, a ceU-in-ceU process, has been implicated in the formation of aneuploidy associated with an aberrant cell division control. Microtubule plus-end-tracking protein TI P150 facilitates the loading of MCAK onto the microtubule plus ends and orchestrates micro- tubule plus-end dynamics during cell division. Here we show that TIP150 cooperates with MCAK to govern entosis via a regulatory cir- cuitry that involves Aurora A-mediated phosphorylation of MCAK. Our biochemical analyses show that MCAK forms an intra-molecular association, which is essential for TIP150 binding. Interestingly, Aurora A-mediated phosphorylation of MCAK modulates its intra-mo- lecular association, which perturbs the MCAK-TI P150 interaction in vitro and inhibits entosis in vivo. To probe if MCAK-TIP150 inter- action regulates microtubule plasticity to affect the mechanical properties of ceUs during entosis, we used an optical trap to measure the mechanical rigidity of live MCF7 ceils. We find that the MCAK cooperates with TIP150 to promote microtubule dynamics and modulate the mechanical rigidity of the cells during entosis. Our results show that a dynamic interaction of MCAK-TI P150 orchestrated by Aurora A-mediated phosphorylation governs entosis via regulating microtubule plus-end dynamics and cell rigidity. These data reveal a previously unknown mechanism of Aurora A regulation in the control of microtubule plasticity during ceU-in-ceU pro- cesses.展开更多
LRP6, a co-receptor for the morphogen Wnt, aids endocytosis of anthrax complexes. Here we report that Dickkopfl （DKK1） protein, a secreted LRP6 ligand and antagonist, is also a modulator of anthrax toxin sensitivity...LRP6, a co-receptor for the morphogen Wnt, aids endocytosis of anthrax complexes. Here we report that Dickkopfl （DKK1） protein, a secreted LRP6 ligand and antagonist, is also a modulator of anthrax toxin sensitivity, shRNA-mediated gene silencing or TALEN-mediated gene knockout of DKK1 reduced sensitivity of cells to PA-dependent hybrid toxins. However, unlike the solely inhibitory effect on Wnt signaling, the effects of DKK1 overexpression on anthrax toxicity were bidirectional, depending on its endogenous expression and cell context. Fluorescence microscopy and biochemical analyses showed that DKK1 facilitates internalization of anthrax toxins and their receptors, an event mediated by DKK1-LRP6-Kremen2 complex. Monoclonal antibodies against DKK1 provided dose-dependent protection to macrophages from killing by anthrax lethal toxin （LT）. Our discovery that DKK1 forms ternary structure with LRP6 and Kremen2 in promoting PA-mediated toxin internalization provides a paradigm for bacterial exploitation of mechanisms that host cells use to internalize signaling proteins.展开更多
基金This study was funded by grants from the Natural Science Foundation of Hubei Province in China （2012FFB02508）.
文摘Background Our previous study showed that the combined Chinese herbs containing scutellaria baicalensis georgi and gardenia jasminoids ellis inhibited atherosclerosis. In this study, we sought to determine if baicalin and geniposide could inhibit atherosclerosis through Wntl and dickkopf-related protein-1 （DKK1）. Methods The wild-type and ApoE-/- mice were treated with baicalin, geniposide, and baicalin plus geniposide daily by gavage for 12 weeks. Blood lipid levels were measured with an automatic biochemistry analyzer. Aortic atherosclerotic lesion areas were analyzed with Image-ProPlus software. The mRNA and protein expression of DKK1, Wntt and nuclear factor-r,B （NF-κB） were measured with RT-PCR and Westem Blot. Serum levels of interleukin-12 （IL-12） were quantified with ELISA. Results The baicalin or geniposide monotherapy as well as combination therapy inhibited the development of atherosclerotic lesions, increased Wntl and decreased DKKI expression and elevated the ratio of Wntl/DKK1 compared with high-lipid diet group. However, only baicalin or geniposide monotherapy decreased NF-κB expression. Moreover, baicalin and geniposide monoor combination therapy lowered IL-12 levels. Geniposide reduced both serum total cholesterol and low density lipoprotein levels, while baicalin either alone or in combination with geniposide did not affect serum lipid levels. In human, umbilical vein endothelial ceils stimulated by oxidized low density lipoprotein, baicalin and geniposide also increased Wntl and decreased DKK1 expression and elevated the ratio of Wntl/DKK1. Condusions Baicalin and geniposide exert inflammation-regulatory effects and may prevent atherosclerotic lesions through enhancing Wntl and inhibit- ing DKK1 expression.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.20433050 and No.20673106）.
文摘The influence of internal noise on the calcium oscillations is studied. It is found that stochastic calcium oscillations occur when the internal noise is considered, while the corresponding deterministic dynamics only yields a steady state. Also,. the performance of such oscillations shows two maxima with the variation of the system size, indicating the occurrence of system size resonance. This behavior is found to be intimately connected with the canard phenomenon. Interestingly, it is also found that one of the optimal system sizes matches well with the real cell size, and such a match is robust to the variation of the control parameters.
文摘Entosis, a ceU-in-ceU process, has been implicated in the formation of aneuploidy associated with an aberrant cell division control. Microtubule plus-end-tracking protein TI P150 facilitates the loading of MCAK onto the microtubule plus ends and orchestrates micro- tubule plus-end dynamics during cell division. Here we show that TIP150 cooperates with MCAK to govern entosis via a regulatory cir- cuitry that involves Aurora A-mediated phosphorylation of MCAK. Our biochemical analyses show that MCAK forms an intra-molecular association, which is essential for TIP150 binding. Interestingly, Aurora A-mediated phosphorylation of MCAK modulates its intra-mo- lecular association, which perturbs the MCAK-TI P150 interaction in vitro and inhibits entosis in vivo. To probe if MCAK-TIP150 inter- action regulates microtubule plasticity to affect the mechanical properties of ceUs during entosis, we used an optical trap to measure the mechanical rigidity of live MCF7 ceils. We find that the MCAK cooperates with TIP150 to promote microtubule dynamics and modulate the mechanical rigidity of the cells during entosis. Our results show that a dynamic interaction of MCAK-TI P150 orchestrated by Aurora A-mediated phosphorylation governs entosis via regulating microtubule plus-end dynamics and cell rigidity. These data reveal a previously unknown mechanism of Aurora A regulation in the control of microtubule plasticity during ceU-in-ceU pro- cesses.
基金supported in part by the National Natural Science Foundation of China(30770465,31070115)the National Basic Research Program of China(2010CB911800)+1 种基金the Peking-Tsinghua Center for Life Sciences(to WenSheng Wei)by an award(HDTRA1-06-C-0039)from the US Defense Threat Reduction Agency(to Stanley N.Cohen)
文摘LRP6, a co-receptor for the morphogen Wnt, aids endocytosis of anthrax complexes. Here we report that Dickkopfl （DKK1） protein, a secreted LRP6 ligand and antagonist, is also a modulator of anthrax toxin sensitivity, shRNA-mediated gene silencing or TALEN-mediated gene knockout of DKK1 reduced sensitivity of cells to PA-dependent hybrid toxins. However, unlike the solely inhibitory effect on Wnt signaling, the effects of DKK1 overexpression on anthrax toxicity were bidirectional, depending on its endogenous expression and cell context. Fluorescence microscopy and biochemical analyses showed that DKK1 facilitates internalization of anthrax toxins and their receptors, an event mediated by DKK1-LRP6-Kremen2 complex. Monoclonal antibodies against DKK1 provided dose-dependent protection to macrophages from killing by anthrax lethal toxin （LT）. Our discovery that DKK1 forms ternary structure with LRP6 and Kremen2 in promoting PA-mediated toxin internalization provides a paradigm for bacterial exploitation of mechanisms that host cells use to internalize signaling proteins.
