目的观察BAPTA-AM对胞外酸化诱导大鼠关节软骨细胞自噬作用的影响,探讨其可能的作用机制。方法体外使用胰酶-Ⅱ型胶原酶消化法分离提取大鼠关节软骨细胞,分为正常组(p H 7.4)、酸化组(p H 6.0)、以及分别经BAPTA-AM处理的正常组和酸化组...目的观察BAPTA-AM对胞外酸化诱导大鼠关节软骨细胞自噬作用的影响,探讨其可能的作用机制。方法体外使用胰酶-Ⅱ型胶原酶消化法分离提取大鼠关节软骨细胞,分为正常组(p H 7.4)、酸化组(p H 6.0)、以及分别经BAPTA-AM处理的正常组和酸化组,激光共聚焦技术检测软骨细胞胞内钙离子变化,实时荧光定量PCR法检测细胞自噬基因Beclin-1、ULK1 mRNA的表达,Western blot法检测自噬蛋白LC3的表达,吖啶橙染色分析细胞自噬溶酶体形成情况。结果与p H 7.4正常组比较,p H 6.0酸化刺激明显增加大鼠关节软骨细胞内Ca2+的浓度,且自噬标志物Beclin-1、ULK1 mRNA及LC3Ⅱ蛋白表达均明显升高,酸性自噬溶酶体形成增多,同时酸化刺激能引起Ca MKKβ及pAMPK蛋白表达水平增高,磷酸化蛋白p-m TOR水平明显降低。BAPTA-AM酸化组自噬水平和Ca MKKβ及p-AMPK表达明显降低,p-m TOR表达明显升高。结论 BAPTA-AM能明显减弱胞外酸化诱导软骨细胞自噬作用,其机制可能与抑制胞内Ca2+有关。展开更多
Early pathogenesis of ischemia-reperfusion(I/R)-induced acute kidney injury(AKI)is dominated by intracellular calcium overload,which induces oxidative stress,intracellular energy metabolism disorder,inflammatory activ...Early pathogenesis of ischemia-reperfusion(I/R)-induced acute kidney injury(AKI)is dominated by intracellular calcium overload,which induces oxidative stress,intracellular energy metabolism disorder,inflammatory activation,and a series of pathologic cascaded reactions that are closely intertwined with self-amplifying and interactive feedback loops,ultimately resulting in cell damage and kidney failure.Currently,most nanomedicines originate from the perspective of antioxidant stress,which can only quench existing reactive oxide species(ROS)but cannot prevent the continuous production of ROS,resulting in insufficient efficacy.As a safe and promising drug,BAPTA-AM is hydrolyzed into BAPTA by intracellular esterase upon entering cells,which can rapidly chelate with overloaded Ca^(2+),restoring intracellular calcium homeostasis,thus inhibiting ROS regeneration at the source.Here,we designed a KTP-targeting peptide-modified yolk-shell structure of liposome–poly(ethylene glycol)methyl ether-block-poly(L-lactide-co-glycolic)(mPLGA)hybrid nanoparticles(<100 nm),with the characteristics of high encapsulation rate,high colloid stability,facile modification,and prolonged blood circulation time.Once the BA/mPLGA@Lipo-KTP was targeted to the site of kidney injury,the cholesteryl hemisuccinate(CHEMS)in the phospholipid bilayer,as an acidic cholesterol ester,was protonated in the simulated inflammatory slightly acidic environment(pH 6.5),causing the liposomes to rupture and release the BA/mPLGA nanoparticles,which were then depolymerized by intracellular esterase.The BAPTA-AM was diffused and hydrolyzed to produce BAPTA,which can rapidly cut off the malignant loop of calcium overload/ROS generation at its source,blocking the endoplasmic reticulum(ER)apoptosis pathway(ATF4–CHOP–Bax/Bcl-2,Casp-12–Casp-3)and the inflammatory pathway(TNF-α–NF-κB–IL-6 axes),thus alleviating pathological changes in kidney tissue,thereby inhibiting the expression of renal tubular marker kidney injury molecule 1(Kim-1)(reduced by 82.9%)and also exhibiting prominent anti-apoptotic capability(TUNEL-positive ratio decreased from 40.2%to 8.3%),significantly restoring renal function.Overall,this research holds huge potential in the treatment of I/R injury-related diseases.展开更多
文摘目的观察BAPTA-AM对胞外酸化诱导大鼠关节软骨细胞自噬作用的影响,探讨其可能的作用机制。方法体外使用胰酶-Ⅱ型胶原酶消化法分离提取大鼠关节软骨细胞,分为正常组(p H 7.4)、酸化组(p H 6.0)、以及分别经BAPTA-AM处理的正常组和酸化组,激光共聚焦技术检测软骨细胞胞内钙离子变化,实时荧光定量PCR法检测细胞自噬基因Beclin-1、ULK1 mRNA的表达,Western blot法检测自噬蛋白LC3的表达,吖啶橙染色分析细胞自噬溶酶体形成情况。结果与p H 7.4正常组比较,p H 6.0酸化刺激明显增加大鼠关节软骨细胞内Ca2+的浓度,且自噬标志物Beclin-1、ULK1 mRNA及LC3Ⅱ蛋白表达均明显升高,酸性自噬溶酶体形成增多,同时酸化刺激能引起Ca MKKβ及pAMPK蛋白表达水平增高,磷酸化蛋白p-m TOR水平明显降低。BAPTA-AM酸化组自噬水平和Ca MKKβ及p-AMPK表达明显降低,p-m TOR表达明显升高。结论 BAPTA-AM能明显减弱胞外酸化诱导软骨细胞自噬作用,其机制可能与抑制胞内Ca2+有关。
基金supported by the Taishan Scholar Foundation of Shandong Province(No.tsqn202211065)Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City(No.2021JJLH0037)+1 种基金the Natural Science Foundation of China(No.82003673)the Fundamental Research Funds for the Central Universities(No.202113049)。
文摘Early pathogenesis of ischemia-reperfusion(I/R)-induced acute kidney injury(AKI)is dominated by intracellular calcium overload,which induces oxidative stress,intracellular energy metabolism disorder,inflammatory activation,and a series of pathologic cascaded reactions that are closely intertwined with self-amplifying and interactive feedback loops,ultimately resulting in cell damage and kidney failure.Currently,most nanomedicines originate from the perspective of antioxidant stress,which can only quench existing reactive oxide species(ROS)but cannot prevent the continuous production of ROS,resulting in insufficient efficacy.As a safe and promising drug,BAPTA-AM is hydrolyzed into BAPTA by intracellular esterase upon entering cells,which can rapidly chelate with overloaded Ca^(2+),restoring intracellular calcium homeostasis,thus inhibiting ROS regeneration at the source.Here,we designed a KTP-targeting peptide-modified yolk-shell structure of liposome–poly(ethylene glycol)methyl ether-block-poly(L-lactide-co-glycolic)(mPLGA)hybrid nanoparticles(<100 nm),with the characteristics of high encapsulation rate,high colloid stability,facile modification,and prolonged blood circulation time.Once the BA/mPLGA@Lipo-KTP was targeted to the site of kidney injury,the cholesteryl hemisuccinate(CHEMS)in the phospholipid bilayer,as an acidic cholesterol ester,was protonated in the simulated inflammatory slightly acidic environment(pH 6.5),causing the liposomes to rupture and release the BA/mPLGA nanoparticles,which were then depolymerized by intracellular esterase.The BAPTA-AM was diffused and hydrolyzed to produce BAPTA,which can rapidly cut off the malignant loop of calcium overload/ROS generation at its source,blocking the endoplasmic reticulum(ER)apoptosis pathway(ATF4–CHOP–Bax/Bcl-2,Casp-12–Casp-3)and the inflammatory pathway(TNF-α–NF-κB–IL-6 axes),thus alleviating pathological changes in kidney tissue,thereby inhibiting the expression of renal tubular marker kidney injury molecule 1(Kim-1)(reduced by 82.9%)and also exhibiting prominent anti-apoptotic capability(TUNEL-positive ratio decreased from 40.2%to 8.3%),significantly restoring renal function.Overall,this research holds huge potential in the treatment of I/R injury-related diseases.
