酒精性肝病与内质网应激

酒精性肝病是由于长期饮酒引起的肝脏病变,酒精性脂肪肝,酒精性肝炎,酒精性肝硬化是其常见的三种肝损伤.它们常同时并存并相互发展转化.在酒精性肝病的发病过程中,肝细胞的凋亡和坏死同时存在.内质网应激(endoplasmic reticulum stress,ERS)是细胞的一种自我保护机制,但也可能是引起肝细胞凋亡的一个原因.

Endoplasmic reticulum stress is closely involved in the early stage of diabetic retinopathy. In the present study, a streptozotocin-induced diabetic animal model was given an intraperitoneal injection of tauroursodeoxycholic acid. Results from immunofluorescent co-localization experiments showed that both caspase-12 protein and c-Jun N-terminal kinase 1 phosphorylation levels significantly in-creased, which was associated with retinal ganglion celldeath in diabetic retinas. The C/ERB ho-mologous protein pathway directly contributed to glial reactivity, and was subsequently responsible for neuronal loss and vascular abnormalities in diabetic retinopathy. Our experimental findings in-dicate that endoplasmic reticulum stress plays an important role in diabetes-induced retinal neu-ronal loss and vascular abnormalities, and that inhibiting the activation of the endoplasmic reticulum stress pathway provides effective protection against diabetic retinopathy.

重视心血管疾病中的内质网应激机制——从细胞应激的基本反应到临床防治的思考

基因组学和蛋白组学的发展极大地推动了生物医学的进步.近年来,以蛋白质为中心,上呈基因下联功能表型的研究为临床疾病的防治开拓了新的领域.内质网应激(endoplasmic reticulum stress,ERS)即是这样一个新概念.蛋白质功能取决于其正确折叠和修饰,这主要由内质网完成,内质网还调控脂质和胆固醇合成、钙稳态、细胞凋亡和自噬等细胞基本生命活动.内质网通过启动并整合细胞核、线粒体和高尔基体等亚细胞器反应,以决定应激细胞的转归:恢复自稳态和修复损伤,或损伤加重乃至死亡.

AIM:To establish the endoplasmic reticulum stress ( ERS) cell model in vascular smooth muscle cells ( VSMCs) of Sprague-Dawley (SD) rats.METHODS:Under sterile condition, the coronary arteries were isolated from SD rats .The primary VSMCs were cultured by tissue-sticking method , and observed the basic morphological characteristics under optical microscope .The marker proteins of VSMCs including α-smooth muscle actin (α-SMA) and smooth muscle myosin heavy chain ( SM-MHC) were identified by immuno-fluorescence technique .VSMCs were treated with thapsigargin (0.5, 1 and 2 μmol/L) for 24 h, and the expression levels of binding immunoglobulin protein (BiP) and C/EBP homologus protein (CHOP), the marker molecules of ERS, were detected using Western blotting.RESULTS:VSMCs climbed out from coronary artery tissues after about six days , and the cells had a nice state and formed the VSMC-like typical "peak valley".The results of immunofluorescence technique show that the marker proteins of VSMCs ,α-SMA and SM-MHC were expressed significantly .The results of Western blotting show that the protein expression levels of BiP and CHOP were increased by thapsigargin in a dose-dependent manner .CONCLUSION:VSMCs can be successfully cultured by tissue-sticking method and built the ERS model induced by thapsigargin .

AIM:To investigate the relationship between polyamine metabolism and hypoxia /ischemia ( H/I)-induced cell apoptosis and to determine the mechanisms by which exogenous spermine protects cell apoptosis against AMI in rats .METHOD:The left anterior de-scending coronary artery ( LAD) of the Wistar rats were ligated , and neonatal rat cardiomyocytes were placed under hypoxic conditions for 24 h to establish the model of AMI (or H/I).Exogenous spermine was administered by intraperitoneal injection (2.5 mg/kg daily for 7 days) in vitro and subjected to the cell medium at 5μmol/L as a pre-treatment therapy.RESULTS:AMI (or H/I) induced an increase in polyamine catabolized enzyme SSAT and a decrease in polyamine biosynthesis enzyme ODC , which result in endogenous spermine and spermidine decrease and putrescine increase .At the same time, AMI ( or H/I) lowered cardiac function , increased cTnI and CK-MB concentrations , aggravated myocardial infarct size , cardiomyocyte damage and apoptosis , raised ROS generation , increased the expression of cleaved caspase-3, cleaved caspase-9 and endoplasmic reticulum stress (ERS)-related proteins, promoted the release of cytochrome C and mPTP opening , down-regulated Bcl-2 expression and the phosphorylation of ERK 1/2, PI3K, Akt and GSK-3β, and activated PERK and eIF 2αphosphorylation .Spermine pre-treatment reversed the above-motioned changes .CONCLUSION:AMI ( or H/I ) could induce cardiomyocyte apoptosis and polyamine metabolism disorder .Exogenous spermine attenuates cardiac injury through scavenging the ROS and inhibiting mPTP opening and ERS injury .These findings provide a novel target for the prevention of apoptosis in the setting of AMI .

BACKGROUND:?Inevitable? warm? ischemia? time? before?organ?procurement?aggravates?posttransplantation?ischemia-reperfusion? injury.? Endoplasmic? reticulum? (ER)? stress? is?involved?in?ischemia-reperfusion?injury,?but?its?role?in?donation?after?cardiac?death?(DCD)?liver?transplantation?is?not?clear?and?the?effect?of?ER?stress?inhibitors,?tauroursodeoxycholic?acid?(TUDCA)?and?4-phenyl?butyric?acid?(PBA),?on?the?prognosis?of?recipient?of?DCD?liver?transplantation?remains?unclear.
METHODS:?Male? Sprague-Dawley? rats? (8-10? weeks)? were?randomly?divided?into?control?group:?liver?grafts?without?warm?ischemia?were?implanted;?DCD?group:?warm?ischemia?time?of?the?liver?grafts?was?60?minutes;?TUDCA?and?PBA?groups:?based?on?the?DCD?group,?donors?were?intraperitoneally?injected?with?TUDCA?or?PBA?30?minutes?before?the?organ?procurements.?Serum? aminotransferase? levels,? oxidative? stress? activation?and?expression?of?ER?stress?signal?molecules?were?evaluated.?Pathological?examinations?were?performed.?The?survivals?of?the?recipients?in?each?group?were?compared?for?14?days.
RESULTS:?Compared?with?the?control?group,?DCD?rats?had?signiifcantly?higher?levels?of?serum?aminotransferase?at?6?hours,?1?day?and?3?days?after?operation?(P<0.01,?0.01?and?0.05,?respectively)?and?oxidative?indices?(P<0.01?for?both?malondialdehyde?and?8-hydroxy?deoxyguanosine),?more?severe?liver?damage?(P<0.01)?and? up-regulated? ER? stress? signal? expressions? (P<0.01? for?GRP78,?phos-eIF2α1,?CHOP,?ATF-4,?ATF-6,?PERK,?XBP-1?and?pro-caspase-12).?All?recipients?died?within?3?days?after?liver?transplantation.?Administration?of?TUDCA?or?PBA?signiifcantly?decreased?aminotransferase?levels?(P<0.05),?increased?superoxide?dismutase?activities?(P<0.01),?alleviated?liver?damage?(P<0.01),?down-regulated? ER? stress? signal? expressions? (P<0.01)? and?improved?postoperative?survivals?(P<0.01).
CONCLUSIONS:?ER?stress?was?involved?with?DCD?liver?trans-plantation?in?rats.?Preoperative?intraperitoneally?injection?of?TUDCA?or?PBA?protected?ER?stress?and?improved?prognosis.