血红素氧合酶1修饰骨髓间充质干细胞多点注射梗死灶周围对梗死后心肌结构重塑的影响

背景：研究表明血红素氧合酶1的过表达有抗炎症反应的作用,将血红素氧合酶1修饰的骨髓间充质干细胞（HO-1-BMSCs）移植入梗死心脏周围是否可调节基质金属蛋白酶/组织金属蛋白酶抑制剂的比例而明显改善梗死心肌重构呢？目的：观察血红素氧合酶1修饰的骨髓间充质干细胞移植对心肌梗死后心肌胶原的调节及心肌重塑的逆转作用。方法：利用血红素氧合酶1腺病毒转染体外培养扩增的骨髓间充质干细胞。结扎大鼠左前降支动脉制造心肌梗死模型,1h后,分别将HO-1-BMSCs、BMSCs多点注射到大鼠心脏梗死区四周,对照组注射等量磷酸盐缓冲液。结果与结论：Adv-hHO-1转染BMSCs后获稳定表达;hHO-1-mRNA仅在HO-1-BMSCs移植组表达;与对照组相比,HO-1-BMSCs移植组基质金属蛋白酶2/9的表达显著减少（P〈0.05）,Null-BMSCs组基质金属蛋白酶2/9的表达虽然减少,但差异无显著性意义（P〉0.05）;与对照组相比,细胞移植组金属蛋白酶组织抑制剂2/3的表达显著增加,尤以HO-1-BMSCs组明显（P〈0.05）;但金属蛋白酶组织抑制剂1无明显变化（P〉0.05）。金属蛋白酶组织抑制剂2/基质金属蛋白酶2和金属蛋白酶组织抑制剂3/基质金属蛋白酶9的比例在细胞移植的心脏中明显上升。与对照组比较,细胞移植组心室中的胶原蛋白沉积减少,心室腔内径显著缩小。结果表明血红素氧合酶1修饰的骨髓间充质干细胞移植可使基质金属蛋白酶/组织金属蛋白酶抑制剂的比例正常化,并逆转心肌细胞外基质的重构。     

骨髓间充质干细胞经核转录因子κB途径干预心肌纤维化

背景:骨髓间充质干细胞移植能否直接干预心肌纤维化及其可能的机制尚不完全清楚。目的:观察骨髓间充质干细胞移植干预心肌纤维化的效果并分析其机制。方法:分离培养雄性小鼠骨髓间充质干细胞,经尾静脉输入异丙肾性心肌纤维化雌性小鼠为治疗组,另设未治疗组和正常对照组。5周后处死小鼠,实时荧光定量PCR检测心肌y染色体鉴别基因(SRY)、基质金属蛋白酶9、基质金属蛋白酶组织抑制剂1的表达;天狼猩红染色对比心脏胶原纤维含量;免疫组织化学染色法观察心脏核转录因子κB表达。结果与结论:骨髓间充质干细胞能归巢于纤维化心肌。与未治疗组相比,治疗组的心肌基质金属蛋白酶9、基质金属蛋白酶组织抑制剂1和核转录因子κB表达下调(P<0.05),胶原纤维含量下降(P<0.05)。结果表明,骨髓间充质干细胞移植干预心肌纤维化,其机制可能与抑制核转录因子κB过度活化有关。     

骨髓间充质干细胞经核转录因子κB途径干预心肌纤维化

背景：骨髓间充质干细胞移植能否直接干预心肌纤维化及其可能的机制尚不完全清楚。目的：观察骨髓间充质干细胞移植干预心肌纤维化的效果并分析其机制。方法：分离培养雄性小鼠骨髓间充质干细胞,经尾静脉输入异丙肾性心肌纤维化雌性小鼠为治疗组,另设未治疗组和正常对照组。5周后处死小鼠,实时荧光定量PCR检测心肌y染色体鉴别基因（SRY）、基质金属蛋白酶9、基质金属蛋白酶组织抑制剂1的表达;天狼猩红染色对比心脏胶原纤维含量;免疫组织化学染色法观察心脏核转录因子κB表达。结果与结论：骨髓间充质干细胞能归巢于纤维化心肌。与未治疗组相比,治疗组的心肌基质金属蛋白酶9、基质金属蛋白酶组织抑制剂1和核转录因子κB表达下调（P〈0.05）,胶原纤维含量下降（P〈0.05）。结果表明,骨髓间充质干细胞移植干预心肌纤维化,其机制可能与抑制核转录因子κB过度活化有关。     

血红素氧合酶1提高骨髓间充质干细胞在梗死后心脏的存活

背景:移植骨髓间充质干细胞(bone mesenchymal stem cells,BMSCs)修复梗死后心功能受到围移植期移植细胞大量死亡的限制.因此寻找一种保护因子对移植细胞提供保护至关重要.目的:观察血红素氧合酶1(heme oxygenase,HO-1)对BMSCs在梗死后心脏生存的影响.方法:体外分离扩增培养大鼠BMSCs,Adv-hHO-1、Adv-GFP分别转染,移植前DAPI标记.结扎左前降支1 h后,分别将DAPI-hHO-1-BMSCs、DAPI-GFP-BMSCs多点注射到大鼠心脏梗死区周边,对照组注射等量PBS.结果与结论:Adv-hHO-1转染BMSCs后获稳定表达.仅hHO-1-BMSCs组稳定表达hHO-1 mRNA;hHO-1-BMSCs组血管内皮生长因子、碱性成纤维细胞生长因子、肝细胞生长因子表达均高于其他两组(P < 0.01);存活BMSCs数量在第3,7天均明显高于GFP-BMSCs组(P < 0.05);大鼠心功能各项参数明显优于其他两组(P < 0.01).移植4周后,HO-1-BMSCs组梗死区周边毛细血管密度明显高于GFP-BMSCs组和对照组(P < 0.01),且胶原蛋白沉积减少,心室壁变厚,梗死面积较其他两组明显缩小(P < 0.01).提示HO-1提高移植到梗死心脏BMSCs的存活,HO-1协同BMSCs抑制心室重构,改善心功能.     

血红素氧合酶1提高骨髓间充质干细胞在梗死后心脏的存活

背景：移植骨髓间充质干细胞（bone mesenchymal stem cells,BMSCs）修复梗死后心功能受到围移植期移植细胞大量死亡的限制。因此寻找一种保护因子对移植细胞提供保护至关重要。目的：观察血红素氧合酶1（heme oxygenase,HO-1）对BMSCs在梗死后心脏生存的影响。方法：体外分离扩增培养大鼠BMSCs,Adv-hHO-1、Adv-GFP分别转染,移植前DAPI标记。结扎左前降支1h后,分别将DAPI-hHO-1-BMSCs、DAPI-GFP-BMSCs多点注射到大鼠心脏梗死区周边,对照组注射等量PBS。结果与结论：Adv-hHO-1转染BMSCs后获稳定表达。仅hHO-1-BMSCs组稳定表达hHO-1 mRNA;hHO-1-BMSCs组血管内皮生长因子、碱性成纤维细胞生长因子、肝细胞生长因子表达均高于其他两组（P〈0.01）;存活BMSCs数量在第3,7天均明显高于GFP-BMSCs组（P〈0.05）;大鼠心功能各项参数明显优于其他两组（P〈0.01）。移植4周后,HO-1-BMSCs组梗死区周边毛细血管密度明显高于GFP-BMSCs组和对照组（P〈0.01）,且胶原蛋白沉积减少,心室壁变厚,梗死面积较其他两组明显缩小（P〈0.01）。提示HO-1提高移植到梗死心脏BMSCs的存活,HO-1协同BMSCs抑制心室重构,改善心功能。     

接受骨髓间充质干细胞移植的心肌梗死后慢性心力衰竭大鼠心肌组织基质金属蛋白酶及抑制剂的变化

背景:Ⅰ型及Ⅲ型胶原含量与比例的变化是促使心脏几何形态改变、心肌收缩和舒展功能的重要因素,基质金属蛋白酶2及抑制剂是胶原代谢的主要调节物质。心肌梗死后心力衰竭大鼠接受骨髓干细胞移植后,心肌组织中这些指标会发生哪些变化?目的:观察接受骨髓干细胞移植治疗的心肌梗死后慢性心力衰竭大鼠,心肌组织中胶原含量与比例、基质金属蛋白酶2及抑制剂的变化。设计:随机对照实验。单位:解放军总医院老年心血管病科和北京医科大学生物化学系。材料:实验于2004-07/2005-12在北京医科大学生物化学系周春燕实验室完成。实验动物由北京医科大学动物实验中心提供,选取4周龄清洁级雄性SD大鼠用于骨髓间充质干细胞的制备,200~250g清洁级雌性SD大鼠14只用于心肌梗死后心力衰竭模型的制备,实验过程中对动物处置符合动物伦理学标准。方法:采用梯度离心法与贴壁培养法分离纯化、扩增骨髓间充质干细胞。结扎雌性SD大鼠左冠状动脉制作急性心肌梗死后心力衰竭模型。造模成功4周后将14只大鼠随机分为2组:移植组大鼠梗死后心肌瘢痕区接受雄性SD大鼠来源的5×106骨髓间充质干细胞。对照组大鼠梗死后心肌瘢痕区接受等体积磷酸盐缓冲液。每组7只。主要观察指标:移植治疗后21d:①以苏木精-伊红染色和Masson染色评价左心室形态。②以免疫组织化学分析心肌基质金属蛋白酶2及抑制剂与瘢痕区Ⅰ型及Ⅲ型胶原的变化。③以Western杂交检测基质金属蛋白酶2及抑制剂蛋白的变化。结果:14只大鼠均进入结果分析,无脱失值。与对照组大鼠比较,骨髓间充质干细胞移植大鼠心肌梗死瘢痕区Ⅰ型胶原增加,Ⅲ型胶原降低,心肌组织基质金属蛋白酶抑制剂表达增加,基质金属蛋白酶2表达降低,心室壁增厚,心室腔缩小,心功能增强。结论:骨髓间充质干细胞移植心力衰竭大鼠后,基质金属蛋白酶2及抑制剂发生了动态变化,进而影响瘢痕区胶原比例重建,逆转心力衰竭心脏异常的胶原平衡。     

人骨髓间充质干细胞培养上清与肝星状细胞相关酶的分泌

背景：研究证实骨髓间充质干细胞移植治疗能改善甚至逆转肝纤维化,但其具体机制尚不清楚。目的：检测人骨髓问充质干细胞培养上清对肝星状细胞中基质金属蛋白酶2及组织抑制基质金属蛋白酶1表达的影响。方法;采用密度梯度离心法分离人骨髓间充质干细胞,收集原代培养7d的骨髓问充质千细胞培养上清,加入肝星状细胞中培养作为实验组,并设置单独肝星状细胞组、单独骨髓间充质干细胞组为对照。培养24,48h后,检测各组细胞上清中基质金属蛋白酶2蛋白与组织抑制基质金属蛋白酶1蛋白的表达。结果与结论：与单独肝星状细胞组、单独骨髓问充质于细胞组比较,实验组培养24,48h后肝星状细胞基质金属蛋白酶2及组织抑制基质金属蛋白酶1表达减少（P〈0．05或P〈0．01）。表明骨髓间充质干细胞培养上清抑制肝星状细胞中基质金属蛋白酶2、组织抑制基质会属蛋白酶1的表达。     

金属蛋白酶组织抑制因子转染骨髓间充质干细胞静脉输入治疗缺血性心肌病

背景:金属蛋白酶组织抑制因子1可能通过抑制基质金属蛋白酶活性降低干细胞侵袭能力,提高其归巢修复能力。目的:观察转染金属蛋白酶组织抑制因子1基因骨髓间充质干细胞移植修复损伤心肌的能力。方法:开胸结扎SD大鼠冠状动脉前降支建立心肌梗死模型,1周后随机分组:空白组经尾静脉内注射DMEM悬液;干细胞组经尾静脉内注射含1×107骨髓间充质干细胞的DMEM悬液;绿色荧光蛋白-干细胞组经尾静脉内注射转染带有绿色荧光蛋白基因慢病毒空载体的骨髓间充质干细胞(1×107)DMEM悬液;TIMP-1-shRNA-干细胞组经尾静脉内注射转染TIMP-1-shRNA的骨髓间充质干细胞(1×107)DMEM悬液。结果与结论:造模后,4组大鼠心脏功能受损,收缩能力下降,治疗4周后心脏功能均有不同程度改善:与空白组比较,干细胞组、绿色荧光蛋白-干细胞组、TIMP-1-shRNA-干细胞组心脏收缩功能明显提高(P<0.05),心肌梗死面积百分比明显缩小(P<0.05),梗死区毛细血管密度明显增加(P<0.05),且TIMP-1-shRNA-干细胞组改善程度优于干细胞组、绿色荧光蛋白-干细胞组(P<0.05)。说明转染金属蛋白酶组织抑制因子1基因的骨髓间充质干细胞移植能够明显改善损伤心肌功能,修复缺血性心肌病。     

小鼠骨髓间充质干细胞体外成肌分化中基质金属蛋白酶1的作用

背景:小鼠骨髓间充质干细胞体外成肌诱导分化效率较低。目的:观察基质金属蛋白酶1在体外对小鼠骨髓间充质干细胞成肌分化的作用。方法:利用差速贴壁法体外分离培养小鼠骨髓间充质干细胞并进行鉴定后,按照不同基质金属蛋白酶1药物处理浓度将小鼠骨髓间充质干细胞分成4组,即10μg/L组、1μg/L组、0.1μg/L组、对照组,给予相应处理后,Real-time定量PCR检测MyoD、Desmin mRNA表达,WesternBlotting检测Desmin蛋白表达。结果与结论:利用差速贴壁法分离培养的小鼠骨髓间充质干细胞形态较一致,表面分子检测示CD29+、Sca-1+、CD45-、CD34-,并具有多向分化潜能;经基质金属蛋白酶1处理后,Real-time定量PCR检测示Desmin、MyoD mRNA表达上调,Western Blotting检测示Desmin蛋白表达上调,并且以上各成肌相关基因、蛋白表达增高程度与基质金属蛋白酶1具有浓度依赖性。提示基质金属蛋白酶1在体外可促进骨髓间充质干细胞向肌肉细胞分化。     

NF-κB与基质金属蛋白酶在骨髓单个核细胞心肌移植后的变化

背景:骨髓干细胞能够修复受损心肌,改善不利的心室重构及恶化的心功能,但细胞移植后对梗死心室重构影响的分子机制仍不清楚.目的:观察骨髓单个核细胞心肌移植后,心肌组织NF-κB、基质金属蛋白酶及其抑制因子表达的变化.设计、时间及地点:随机对照动物实验,于2006-07/2007-05在解放军总医院心血管外科实验动物中心和解放军军事医学科学院病原微生物生物安全国家重点实验室完成.材料:成年健康雄性杂种犬24只,随机分为急性心肌梗死对照组、急性心肌梗死移植组、陈旧心肌梗死对照组、陈旧心肌梗死移植组,6只/组.方法:急性心肌梗死对照组、急性心肌梗死移植组在冠状动脉左前降支主干结扎1h,观察缺血梗死区仍然呈暗红色,确认急性心肌梗死模型建立成功.陈旧心肌梗死对照组、陈旧心肌梗死移植组在移植前行超声心动图检查,证实左室前壁和心尖部可见节段性室壁运动异常,确认陈旧心肌梗死模型建立成功.Ficoll分离法获得犬自体骨髓单个核细胞悬液,急性心肌梗死移植组在造模后1h于梗死区及梗死边缘区分多点注射细胞悬液,每点注射0.5 mL,(1～2)×107个细胞/mL;陈旧心肌梗死移植组于造模后4周开胸确认梗死区,同法行细胞移植.主要观察指标:RT-PCR法检测心肌组织基质金属蛋白酶及其抑制因子mRNA的表达,Western免疫印迹法检测心肌组织NF-κB 的表达.结果:移植后6周与相应对照组比较,急性心肌梗死移植组、陈旧心肌梗死移植组的梗死区、梗死周围区基质金属蛋白酶2,9mRNA及NF-κB 表达均显著降低(P<0.01),基质金属蛋白酶抑制因子1,2 mRNA表达均显著升高(P<0.01).结论:犬自体骨髓单个核细胞心肌移植可能通过抑制NF-κB活化,导致基质金属蛋白酶mRNA表达减少及其抑制因子mRNA表达增加,从而抑制梗死后心室重构过程.     

Differential effects of heme oxygenase isoforms on heme mediation of endothelial intracellular adhesion molecule 1 expression.

Heme oxygenase (HO), by catabolizing heme to bile pigments, down-regulates cellular hemoprotein, hemoglobin, and heme; the latter generates pro-oxidant products, including free radicals. Two HO isozymes, the products of distinct genes, have been described; HO-1 is the inducible isoform, whereas HO-2 is suggested to be constitutively expressed. We studied the inducing effect of several metal compounds (CoCl(2), stannic mesoporphyrin, and heme) on HO activity. Additionally, we studied HO-1 expression in experimental models of adhesion molecule expression produced by heme in endothelial cells, and the relationship of HO-1 expression to the induced adhesion molecules. Flow cytometry analysis showed that heme induces intracellular adhesion molecule 1 (ICAM-1) expression in a concentration (10-100 microM)- and time (1-24 h)-dependent fashion in human umbilical vein endothelial cells. Pretreatment with stannic mesoporphyrin, an inhibitor of HO activity, caused a 2-fold increase in heme-induced ICAM-1 expression. In contrast, HO induction by CoCl(2) decreased heme-induced ICAM-1 expression by 33%. To examine the contribution of HO-1 and HO-2 to endothelial HO activity, specific antisense oligonucleotides (ODNs) of each isoform were tested for their specificity to inhibit HO activity in cells exposed to heme. Endothelial cells exposed to heme elicited increased HO activity, which was prevented (70%) by HO-1 antisense ODNs. HO-2 antisense ODN inhibited heme-induced HO activity by 21%. Addition of HO-1 antisense ODNs prevented heme degradation and resulted in elevation of microsomal heme. Western blot analysis showed that HO-1 antisense ODNs selectively inhibited HO-1 protein and failed to inhibit HO-2 protein. Incubation of endothelial cells with HO-1 antisense enhanced heme-dependent increase of ICAM-1. In contrast, addition of HO-2 antisense to endothelial cells failed to increase adhesion molecules. The role of glutathione, an important antioxidant, was examined on heme-induced ICAM-1 expression. Endothelial cells pretreated with a glutathione precursor, N-acetylcysteine, or glutathione ester, showed a decrease in heme-induced ICAM-1 expression of 37 and 44%, respectively, suggesting that the mechanism of ICAM-1 induction by heme may be partly dependent on the levels of antioxidant. It is possible that amelioration of the heme-induced oxidative stress and expression of ICAM-I is due, in part, to the induction of HO-1 activity. Regulation of HO activity in this manner may have clinical applications.     

血红素加氧酶-1对心肌缺血再灌注损伤的保护作用

目的:探讨血红素加氧酶-1(HO-1)对心肌缺血再灌注损伤的保护作用及机制。方法:采用HO-1的诱导剂钴原卟啉(CoPP)和抑制剂锌原卟啉(ZnPP)分别进行干预处理后,建立大鼠的心肌缺血/再灌注损伤模型。观察大鼠再灌注后心肌形态变化,检测HO-1基因在大鼠心肌的表达情况,测定大鼠左心室心肌组织超氧化物歧化酶(SOD)活性及丙二醛(MDA)含量。结果:再灌注前使用CoPP进行预处理,可以诱导HO-1蛋白的表达上调;HO-1蛋白表达上调可以减少缺血再灌注后的心肌细胞坏死,提高心肌组织中SOD含量并降低MDA的含量。结论:CoPP诱导的HO-1过表达可以抑制心肌缺血再灌注损伤后的细胞坏死,从而减轻心肌的再灌注损伤,其主要机制与抗氧自由基有关。     

Carbon monoxide generated by heme oxygenase 1 suppresses endothelial cell apoptosis

Heme oxygenase 1 (HO-1) inhibits apoptosis by regulating cellular prooxidant iron. We now show that there is an additional mechanism by which HO-1 inhibits apoptosis, namely by generating the gaseous molecule carbon monoxide (CO). Overexpression of HO-1, or induction of HO-1 expression by heme, protects endothelial cells (ECs) from apoptosis. When HO-1 enzymatic activity is blocked by tin protoporphyrin (SnPPIX) or the action of CO is inhibited by hemoglobin (Hb), HO-1 no longer prevents EC apoptosis while these reagents do not affect the antiapoptotic action of bcl-2. Exposure of ECs to exogenous CO, under inhibition of HO-1 activity by SnPPIX, substitutes HO-1 in preventing EC apoptosis. The mechanism of action of HO-1/CO is dependent on the activation of the p38 mitogen-activated protein kinase (MAPK) signaling transduction pathway. Expression of HO-1 or exposure of ECs to exogenous CO enhanced p38 MAPK activation by TNF-alpha. Specific inhibition of p38 MAPK activation by the pyridinyl imidazol SB203580 or through overexpression of a p38 MAPK dominant negative mutant abrogated the antiapoptotic effect of HO-1. Taken together, these data demonstrate that the antiapoptotic effect of HO-1 in ECs is mediated by CO and more specifically via the activation of p38 MAPK by CO.     

Heme oxygenase-1 as a protective gene

Heme oxygenases catalyze the rate-limiting step in heme degradation, resulting in the formation of carbon monoxide, iron and biliverdin that is subsequently reduced to bilirubin by biliverdin reductase. The products of this enzymatic reaction have important biological effects, including antioxidant, anti-inflammatory and cytoprotective functions. Three isoforms of heme oxygenase (HO) have been described: two constitutively expressed isoforms, HO-2 and HO-3, and an inducible isoform, HO-1 that is increased as an adaptive response to several injurious stimuli including heme, hyperoxia, hypoxia, endotoxin and heavy metals. Induction of HO-1 has been implicated in numerous clinically relevant disease states including transplant rejection, hypertension, atherosclerosis, lung injury, endotoxic shock and others. This review will focus on the protective functions of HO-1.     

Pseudomonas aeruginosa-induced neutrophilic lung inflammation is attenuated by adenovirus-mediated transfer of the heme oxygenase 1 cDNA in mice

Heme oxygenase (HO) is well known as the rate-limiting enzyme in the oxidative degradation of heme to biliverdin, carbon monoxide (CO), and iron. Based on recent evidence that overexpression of HO-1 confers protection against various types of cell and tissue injury by regulating apoptotic cell death or cytokine expression profiles, the present study was performed to examine whether the transfer of exogenous HO-1 cDNA in the lung would provide therapeutic effect in a murine model of lung inflammation induced by Pseudomonas aeruginosa. HO-1 overexpression clearly attenuated neutrophil influx and decreased numbers of apoptotic bronchial epithelial cells. Interestingly, the overexpression of Bcl-2, a known antiapoptotic factor, was observed and thought to be the mechanism that inhibits bronchial epithelial cellular apoptosis. It is thus suggested that HO-1 overexpression is useful for treating P. aeruginosa-associated lung inflammation by attenuating neutrophil influx and apoptotic cell death.     

Protective effect of heme oxygenase induction in ischemic acute renal failure

OBJECTIVE: To examine the role of heme oxygenase-1 (HO-1) induction in the recovery of renal function in rats with ischemic acute renal failure. DESIGN: Randomized, masked, controlled animal study. SETTING: University-based animal research facility. SUBJECTS: Sprague-Dawley male rats, weighing 200-250 g. INTERVENTIONS: Anesthetized rats were subjected to bilateral flank incisions, and the right kidney was removed. Renal ischemia was performed by left renal microvascular clamping, followed by reflow of the blood. MEASUREMENTS AND MAIN RESULTS: Ischemia of the kidney in the uninephrectomized rat significantly induced HO-1 messenger RNA, protein, and enzyme activity, reaching a maximum at 6 hrs, which was mediated in part through an increase in microsomal heme concentration. Heat shock protein 70 was induced extremely rapidly, reaching a maximum at 1 hr, suggesting that HO-1 and heat shock protein 70 gene expression are regulated separately. Inhibition of HO activity by tin mesoporphyrin, which resulted in an increase in microsomal heme concentration, significantly exacerbated renal function, as judged by the sustained increase in serum creatinine concentration and extensive tubular epithelial cell injuries. In contrast, animals that did not receive tin mesoporphyrin showed normal creatinine concentration and microsomal heme concentration 24 hrs after reperfusion, as well as restoration of abnormal renal histology. CONCLUSION: These findings indicate that the expression of HO-1 in the ischemic kidney may be critical in the recovery of renal cell function in this animal model. These findings also suggest that H0-1 induction may play an important role in conferring protection on renal cells from oxidative damage caused by heme.     

Differential activation of heme oxygenase-1 by chalcones and rosolic acid in endothelial cells

The induction of heme oxygenase-1 (HO-1) is widely recognized as an effective cellular strategy to counteract a variety of stressful events. We have shown that curcumin and caffeic acid phenethyl ester, two naturally occurring phytochemicals that possess antioxidant, anti-inflammatory, and anticarcinogenic activities, induce HO-1 in many cell types. This suggests that stimulation of HO-1 could partly underlie the beneficial effects exerted by these plant-derived constituents. Here we examined the ability of additional plant constituents to up-regulate heme oxygenase activity and HO-1 in aortic endothelial cells. Incubation of endothelial cells with a series of polyphenolic chalcones (5-50 microM) resulted in increased heme oxygenase activity; interestingly, the chemical structure dictated the pattern of heme oxygenase induction, which was unique to each particular compound employed. We also found that rosolic acid, a constituent isolated from the rhizome of Plantago asiatica L. dramatically increased HO-1 in a concentration- and time-dependent manner. Severe cytotoxicity was observed after prolonged exposure (24 or 48 h) of cells to curcumin and caffeic acid phenethyl ester, whereas 2'-hydroxychalcone and rosolic acid did not affect cell viability. By using different mitogen-activated protein kinase inhibitors, we determined that the extracellular signal-regulated kinase, p38, and c-Jun NH(2)-terminal protein kinase pathways play only a minor role in the induction of HO-1 by rosolic acid and 2'-hydroxychalcone. On the other hand, increased intra- and extracellular thiols markedly reduced the rise in heme oxygenase activity elicited by rosolic acid. Thus, this study identified novel plant constituents that highly induce HO-1 in endothelial cells and investigated some of the mechanisms involved in this effect.