目的探讨弱氧化性低密度脂蛋白(minimally modified low density lipoprotein,mmLDL)上调在体小鼠肠系膜动脉ETA受体的作用(endothelin type A receptors,ETA)并考察自噬是否参与这一过程。方法小鼠尾静脉注射mmLDL,腹腔注射ClassⅢPI3...目的探讨弱氧化性低密度脂蛋白(minimally modified low density lipoprotein,mmLDL)上调在体小鼠肠系膜动脉ETA受体的作用(endothelin type A receptors,ETA)并考察自噬是否参与这一过程。方法小鼠尾静脉注射mmLDL,腹腔注射ClassⅢPI3K自噬通路抑制剂6-氨基-3-甲基嘌呤(3-methyladenine,3-MA),探究自噬在mmLDL给药处理小鼠中的作用,微血管张力描记仪观察内皮素-1(endothelin-1,ET-1)引起的小鼠肠系膜动脉收缩量效曲线的变化,RT-PCR定量ETA受体mRNA,Western blot检测ETA受体和ClassⅢPI3K、Beclin-1、LC3-Ⅱ/Ⅰ、p62及p-NF-κB、NF-κB的蛋白水平表达。结果mmLDL引起ET-1收缩量效曲线明显增强,表现为Emax值由生理盐水(NS)组的(184.87±7.46)%上升为(319.91±20.31)%(P<0.001),pEC50值由NS组的(8.05±0.05)上升为(9.11±0.09)(P<0.01)。mmLDL在上调ClassⅢPI3K、beclin-1、LC3-Ⅱ/Ⅰ和下调p62蛋白水平的同时,也引起ETA受体mRNA水平、蛋白表达明显增加,增加了p-NF-κB的蛋白水平;腹腔注射3-MA抑制了mmLDL的这些作用。结论mmLDL能通过ClassⅢPI3K/Beclin-1通路激活自噬及下游NF-κB通路上调ETA受体。展开更多
Using fura-2-acetoxymethyl ester (AM) fluorescence imaging and patch clamp techniques, we found that endothelin-1 (ET-1) significantly elevated the intracellular calcium level ([Ca2+]i) in a dose-dependent manner and ...Using fura-2-acetoxymethyl ester (AM) fluorescence imaging and patch clamp techniques, we found that endothelin-1 (ET-1) significantly elevated the intracellular calcium level ([Ca2+]i) in a dose-dependent manner and activated the L-type Ca2+ channel in cardiomyocytes isolated from rats. The effect of ET-1 on [Ca2+]i elevation was abolished in the presence of the ETA receptor blocker BQ123, but was not affected by the ETB receptor blocker BQ788. ET-1-induced an increase in [Ca2+]i, which was inhibited 46.7% by pretreatment with a high concentration of ryanodine (10 μmol/L), a blocker of the ryanodine receptor. The ET-1-induced [Ca2+]i increase was also inhibited by the inhibitors of protein kinase A (PKA), protein kinase C (PKC) and angiotensin type 1 receptor (AT1 receptor). We found that ET-1 induced an enhancement of the amplitude of the whole cell L-type Ca2+ channel current and an increase of open-state probability (NPo) of an L-type single Ca2+ channel. BQ123 completely blocked the ET-1-induced increase in calcium channel open-state probability. In this study we demonstrated that ET-1 regulates calcium overload through a series of mechanisms that include L-type Ca2+ channel activation and Ca2+-induced Ca2+ release (CICR). ETA receptors, PKC, PKA and AT1 receptors may also contribute to this pathway.展开更多
文摘目的探讨弱氧化性低密度脂蛋白(minimally modified low density lipoprotein,mmLDL)上调在体小鼠肠系膜动脉ETA受体的作用(endothelin type A receptors,ETA)并考察自噬是否参与这一过程。方法小鼠尾静脉注射mmLDL,腹腔注射ClassⅢPI3K自噬通路抑制剂6-氨基-3-甲基嘌呤(3-methyladenine,3-MA),探究自噬在mmLDL给药处理小鼠中的作用,微血管张力描记仪观察内皮素-1(endothelin-1,ET-1)引起的小鼠肠系膜动脉收缩量效曲线的变化,RT-PCR定量ETA受体mRNA,Western blot检测ETA受体和ClassⅢPI3K、Beclin-1、LC3-Ⅱ/Ⅰ、p62及p-NF-κB、NF-κB的蛋白水平表达。结果mmLDL引起ET-1收缩量效曲线明显增强,表现为Emax值由生理盐水(NS)组的(184.87±7.46)%上升为(319.91±20.31)%(P<0.001),pEC50值由NS组的(8.05±0.05)上升为(9.11±0.09)(P<0.01)。mmLDL在上调ClassⅢPI3K、beclin-1、LC3-Ⅱ/Ⅰ和下调p62蛋白水平的同时,也引起ETA受体mRNA水平、蛋白表达明显增加,增加了p-NF-κB的蛋白水平;腹腔注射3-MA抑制了mmLDL的这些作用。结论mmLDL能通过ClassⅢPI3K/Beclin-1通路激活自噬及下游NF-κB通路上调ETA受体。
基金supported by the Fundamental Research Foundation of Beijing Institute of Technology (1050050320704)the National Technological Project of the Manufacture and Innovation of Key New Drugs (2009ZX09103-143)
基金Supported by the National Natural Science Foundation of China (Grant No. 200830870910).
文摘Using fura-2-acetoxymethyl ester (AM) fluorescence imaging and patch clamp techniques, we found that endothelin-1 (ET-1) significantly elevated the intracellular calcium level ([Ca2+]i) in a dose-dependent manner and activated the L-type Ca2+ channel in cardiomyocytes isolated from rats. The effect of ET-1 on [Ca2+]i elevation was abolished in the presence of the ETA receptor blocker BQ123, but was not affected by the ETB receptor blocker BQ788. ET-1-induced an increase in [Ca2+]i, which was inhibited 46.7% by pretreatment with a high concentration of ryanodine (10 μmol/L), a blocker of the ryanodine receptor. The ET-1-induced [Ca2+]i increase was also inhibited by the inhibitors of protein kinase A (PKA), protein kinase C (PKC) and angiotensin type 1 receptor (AT1 receptor). We found that ET-1 induced an enhancement of the amplitude of the whole cell L-type Ca2+ channel current and an increase of open-state probability (NPo) of an L-type single Ca2+ channel. BQ123 completely blocked the ET-1-induced increase in calcium channel open-state probability. In this study we demonstrated that ET-1 regulates calcium overload through a series of mechanisms that include L-type Ca2+ channel activation and Ca2+-induced Ca2+ release (CICR). ETA receptors, PKC, PKA and AT1 receptors may also contribute to this pathway.
