脂多糖介导的血管平滑肌细胞血红素

目的:研究脂多糖(LPS)作用下的血管平滑肌细胞血红素加氧酶-1(HO-1)基因的表达,并探讨HO/一氧化碳(CO)调节通路在内毒素性血管调节功能障碍中的作用。方法:10mg/L、30mg/L及50mg/L的LPS与培养的大鼠主动脉平滑肌细胞(VSMC)共同孵育6h,以及10mg/LLPS与VSMC共同孵育9h和18h。分别观察细胞丙二醛(MDA)含量及乳酸脱氢酶(LDH)活性、台盼蓝染色法记录VSMC蓝染率的变化;Northern杂交测HO-1mRNA表达。结果:VSMCHO-1mRNA表达随LPS浓度的增大而增加,LPS50mg/L时HO-1mRNA表达比对照高176.7%;低剂量LPS(10mg/L)诱导VSMCHO-1mRNA的表达量随诱导时间的延长而增加,18h组HO-1mRNA的表达量比对照高195.6%。只有当LPS浓度增加至50mg/L及10mg/L孵育18h时,细胞台盼蓝摄取率、MDA含量与LDH活性明显增加、细胞出现损伤。结论:LPS可诱导VSMCHO-1mRNA的表达且具有浓度依赖性和时间依赖性,HO/CO可能为介导内毒素性血管平滑肌功能调节障碍的重要通路。     

Toll-like receptor 2 contributes to glial cell activation and heme oxygenase-1 expression in traumatic brain injury

Traumatic brain injury is accompanied by glial cell activation around the site of the injury. In this study, we investigated the role of toll-like receptor 2 (TLR2) in glial cell activation using a stab-wound injury (SWI) model with TLR2 knock-out mice. Penetration of a normal mouse brain with a 26-G needle using a stereotaxic instrument resulted in an 18- and 4-fold upregulation of GFAP and CD11b mRNA, respectively, along the needle track in the injury area. However, in the TLR2 knock-out mice, the induced expression of these genes was reduced by 70% and 40%, respectively. Likewise, there was a reduction in the area of activated glial cells detected by immunohistochemistry and the glial cells had a less-activated morphology in the TLR2 knock-out mice. In addition, the expression of the heme oxygenase-1 (HO-1) gene, a glia-expressing wound-responsive gene, was reduced after SWI in TLR2 knock-out mice. Taken together, these data argue that TLR2 contributes to the glial cell activation and HO-1 gene expression associated with traumatic brain injury.     

Permanent focal and transient global cerebral ischemia increase glial and neuronal expression of heme oxygenase-1, but not heme oxygenase-2, protein in rat brain

Two heme oxygenase (HO) proteins have been identified to date; HO-1, a stress-induced protein, and HO-2, a constitutively expressed isoform. Recently, it was demonstrated that HO-1 mRNA expression is increased following transient global ischemia. The present study examined the effects of global and focal ischemia on HO-1 and HO-2 protein, using immunocytochemistry. Following 20 min of ischemia (rat 4 vessel occlusion model with hypotension) and 6 h of recirculation, increased HO-1 immunoreactivity was evident in hippocampal neurons. After 24 h of recirculation, HO-1 was observed in both hippocampal neurons and astroglial cells. By 72 h, expression was primarily glial and restricted to CA1 and CA3c. In addition to hippocampus, HO-1 was also evident in both neurons and glia in cerebral cortex and thalamus, and in striatal glial cells. Twenty-four hours following permanent focal ischemia, HO-1 immunoreactivity was observed in astroglial cells in the penumbra region surrounding the infarct. In contrast to HO-1, the pattern of HO-2 immunoreactivity was not altered following transient global or permanent focal ischemia. The increased expression of HO-1 following ischemia may confer protection against oxidative stress, but might also contribute to the subsequent neuronal degeneration.     

诱导HO-1基因表达的信号通路

血红素氧合酶（HO）的诱导型HO-1与其催化血红素降解生成的产物胆红素和CO一道，组成了机体重要的内源性保护系统，广泛参与抗炎与多种急慢性氧化应激损伤。多种理化因素通过不同的细胞内信号转导通路诱导HO-1的表达，这些信号通路涉及丝裂原活化蛋白激酶（MAPKs）、蛋白激酶C(PKC)、cAMP依赖的蛋白激酶A(PKA)、cGMP依赖蛋白激酶G（PKG）、酪氨酸蛋白激酶（TPK）、蛋白磷酸酶（PPs）、磷脂酰肌醇（-3）激酶（PI3K）/Akt     

Induction of heme oxygenase-1 expression inhibits platelet-dependent thrombosis

Heme oxygenase-1 (HO-1) plays a key role in protecting tissue from oxidative stress. Although some studies implicate HO-1 in modulating thrombosis after vascular injury, the impact of HO-1 on the rate of clot formation in vivo is poorly defined. This study examined the potential function of HO-1 in regulating platelet-dependent arterial thrombosis. Platelet-rich thrombi were induced in C57BL/6J mice by applying 10% ferric chloride to the exposed carotid artery. Mean occlusion time of wild-type mice (n = 10) was 14.6 +/- 1.0 min versus 12.9 +/- 0.6 min for HO-1-/- mice (n = 11, p = 0.17). However, after challenge with hemin, mean occlusion time was significantly longer in wild-type mice (16.3 +/- 1.2 min, n = 15) than HO-1-/- mice (12.0 +/- 1.0 min, n = 9; p = 0.021). Hemin administration induced an approximately twofold increase in oxidative stress, measured as plasma thiobarbituric acid reactive substances. Immunohistochemical analysis revealed that hemin induced a robust increase in HO-1 expression within the carotid arterial wall. Ex vivo blood clotting within a collagen-coated perfusion chamber was studied to determine whether the accelerated thrombosis observed in HO-1-/- mice was contributed to by effects on the blood itself. Under basal conditions, mean clot formation during perfusion of blood over collagen did not differ between wild-type mice and HO-1-/- mice. However, after hemin challenge, mean clot formation was significantly increased in HO-1-/- mice compared with wild-type controls. These results suggest that, under basal conditions, HO-1 does not exert a significant effect on platelet-dependent clot formation in vivo. However, under conditions that stimulate HO-1 production, platelet-dependent thrombus formation is inhibited by HO-1. Enhanced HO-1 expression in response to oxidative stress may represent an adaptive response mechanism to down-regulate platelet activation under prothrombotic conditions.     

HO-1参与葛根素对抗高糖诱导的大鼠血管舒张功能下降

目的： 研究葛根素对抗急性高糖刺激引起的血管舒张功能的下降,并分析血红素加氧酶（HO-1）在其中的作用。方法: 采用血管环灌流装置,观察大鼠胸主动脉环的舒张效应。结果: ①与空白对照组（含11 mmol/L葡萄糖）相比,经44 mmol/L葡萄糖（高糖）孵育血管2 h后,主动脉环对ACh引起的内皮依赖性血管舒张反应下降。②葛根素（10-10-10-8 mol/L）与高糖联合孵育,可剂量依赖性地改善高糖诱导的血管ACh舒张反应的下降。③葛根素孵育血管后可引起血管HO-1活性增高;用ZnPPIX抑制HO-1的活性后,葛根素抗高糖损伤的作用被取消。结论: 葛根素可以对抗高糖引起的血管舒张功能的下降,其机制可能是通过诱导HO-1而实现的。     

Effects of dexmedetomidine pretreatment on heme oxygenase-1 expression and oxidative stress during one-lung ventilation

Purpose: This study aimed to explore effects of dexmedetomidine pretreatment on heme oxygenase-1 (HO-1) expression and oxidative stress during one-lung ventilation (OLV) in lung cancer patients. Methods: Fifty patients with lung carcinoma (ASA I-II, 40-65 years old, body mass index [BMI] < 30 kg/m²) undergoing pulmonary lobectomy were enrolled. They were divided randomly into two equal groups before anaesthesia induction to receive either intravenous injection of 1 μg/kg dexmedetomidine for 20 min (Dexmedetomidine) or not (Control). Results: The results showed no difference in heart rate (HR), mean arterial pressure (MAP) and bispectral index (BIS) between the two groups, as well as liquid intake and output volume (LIO), duration of OLV and time from surgery beginning to excision of pathological tissues (P > 0.05). Levels of tumor necrosis factor (TNF-α) and malondialdehyde (MDA) in Dexmedetomidine group were lower than that of Control at OLV 60 and 90 (P < 0.05). Superoxide dismutase (SOD) activity and the expression level of HO-1 were higher in Dexmedetomidine group than in Control (P < 0.05). Conclusions: Dexmedetomidine pretreatment could upregulated expression of HO-1 in lung tissue and reduce oxidative stress and inflammation during OLV. Thus dexmedetomidine played a role in protecting lung injury by promoting HO-1 expression.     

Age-dependent increase of heme oxygenase-1 gene expression in the liver mediated by NFkappaB

Heme, the iron-porphyrin coordination complex, released from the degradation of hemoproteins, is a strong prooxidant. It is enzymatically degraded by heme oxygenase to free iron, carbon monoxide and biliverdin. Biliverdin and its reduced metabolite bilirubin are two potent physiological antioxidants. Here we show a progressive increase of steady-state levels of the mRNA encoding the inducible isoform of this enzyme (heme oxygenase-1) in the rat liver during aging. We had previously reported that aging is associated with increased activation of the nuclear factor kappaB (NFkappaB). We now provide evidence to establish that overexpression of NFkappaB in transfected liver-derived HepG2 cells can cause a marked induction of the endogenous heme oxygenase-1 (HO-1) mRNA and activation of the cotransfected HO-1 gene promoter. Taken together, these results support the conclusion that enhanced oxidative stress during aging is accompanied by compensatory induction of the antioxidant enzyme HO-1 through activation of the NFkappaB pathway.     

高浓度氧增加未成年大鼠肺血红素加氧酶-1表达

目的 探讨高浓度氧对未成年大鼠肺血红素加氧酶-1(HO-1)表达的影响.方法 将生后21 d SD大鼠40只随机分为空气组和12、24、48及72 h高氧组,分别置于空气和常压高氧箱(92%~94% O<,2>)中.检测左肺湿/干重比及肺组织病理学改变,用RT-PCR和Western blot法分别检测肺HO-1 mRNA及HO-1蛋白表达情况.结果 高氧12 h组肺HO-1 mRNA吸光度积分相对值和高氧24 h组HO-1蛋白表达水平分别为0.350±0.043和0.455±0.046,较对照组0.263±0.037和0.280±0.044明显升高,且均随高氧暴露时间延长而表达进一步增加(P<0.05,P<0.01).与空气组比较,高氧48 h组和高氧72 h组左肺湿重/干重及肺损伤评分显著增高(P<0.05,P<0.01).结论 高浓度氧可引起未成年大鼠肺组织HO-1表达增多.     

血红素氧合酶1基因表达与慢性低氧高二氧化碳性肺动脉高压的关系

 目的：研究一氧化碳体系对低氧高二氧化碳性肺动脉高压的调控作用。方法：将SD大鼠分为正常对照组(A组),4周低O₂高CO₂组(B组),4周低O₂高CO₂+血晶素组(C组)。采用透射电镜、图像分析、免疫组化、组织原位杂交技术等方法,观察各组大鼠肺动脉平均压(mPAP)、颈动脉平均压(mCAP)、右心室/(左心室+室间隔)重量比、肺细小动脉显微和超微结构、血CO浓度及肺细小动脉HO-1及其基因表达的变化。结果：①B组mPAP、RV/(LV+S)显著高于A组(P<0.01),C组mPAP、RV/(LV+S)明显低于B组(P<0.01),3组间mCAP比较差异无显著性(P>0.05)。②全血CO浓度B组明显高于A组(P<0.01),C组明显高于B组(P<0.01)。③光镜下肺细小动脉管壁面积/管总面积(WT/TA)、肺细小动脉中膜平滑肌细胞核密度(SMC)、肺细小动脉中膜厚度(PAMT)B组显著高于A组(P<0.01),C组明显低于B组(P<0.01)。④电镜下B组肺细小动脉中膜平滑肌细胞增生,面积增大,染色质增多,外膜胶原纤维密集,C组大鼠肺细小动脉中膜平滑肌细胞和外膜胶原纤维增生明显轻于B组。⑤免疫组化、原位杂交发现B组I级(直径＞200μm)、Ⅱ级(直径50-200μm)、Ⅲ级(直径<50 μm)肺细小动脉HO-1及HO-1mRNA平均吸光度值显著高于A组(P均<0.01),C组各级肺细小动脉HO-1及HO-1 mRNA平均吸光度值明显高于B组(P均<0.01)。结论：一氧化碳体系表达增强可抑制慢性低氧高二氧化碳性肺动脉高压的形成和肺血管结构重建,提高一氧化碳体系表达可能是防治COPD、肺动脉高压的新途径。     

丹参对大鼠移植肝血红素氧合酶1表达的影响

背景：器官移植前使用丹参预处理能够保护组织缺血-再灌注损伤,改善移植器官存活率。 目的：观察含丹参的冷灌注液对同种异体大鼠移植肝脏中血红素氧合酶1表达的影响,以及对供体肝脏缺血-再灌注损伤的保护作用。 方法：将SD雄性大鼠随机分成UW液组(术中使用UW液灌注保存)、丹参+UW液组(术中使用丹参+UW液灌注保存)、ZnPP预处理组(移植前24 h腹腔内注射ZnPP,术中使用丹参+UW液灌注保存),建立稳定的大鼠同种异体肝移植模型。同时取10只正常大鼠作为正常对照。 结果与结论：丹参+UW液组和UW液组血清总胆红素、谷丙转氨酶、谷草转氨酶水平明显低于ZnPP预处理组(P < 0.01)。血红素氧合酶1mRNA及其蛋白在丹参+UW液组中较UW组表达更明显,在ZnPP预处理组中表达明显受到抑制(P< 0.05)。丹参+UW液组肝脏Suzuki标准评分明显低于ZnPP预处理组及UW液组(P < 0.05)。表明丹参能上调同种异体的大鼠移植肝脏中血红素氧合酶1 mRNA及其蛋白的表达,减轻供肝缺血-再灌注损伤,保护移植大鼠肝脏。     

Glial heme oxygenase-1 expression in Alzheimer disease and mild cognitive impairment

We determined whether oxidative stress is an early event in the pathogenesis of sporadic Alzheimer disease (AD), and correlated oxidative stress with neuropsychological functions and neurofibrillary pathology in AD and mild cognitive impairment (MCI). Oxidative stress was measured as the percentage of astrocytes expressing heme oxygenase-1 (HO-1) in post mortem temporal cortex and hippocampus after dual HO-1/glial fibrillary acidic protein (GFAP) immunohistochemistry. Glial HO-1 expression in the MCI temporal cortex and hippocampus was significantly greater than in the non-demented group and did not differ from AD values. Astroglial HO-1 expression in the temporal cortex was associated with decreased scores for global cognition, episodic memory, semantic memory and working memory. Hippocampal astroglial HO-1 expression was associated with lower scores for global cognition, semantic memory and perceptual speed. Glial HO-1 immunoreactivity in the temporal cortex, but not hippocampus, correlated with the burden of neurofibrillary pathology. Cortical and hippocampal oxidative stress is a very early event in the pathogenesis of sporadic AD and correlates with the development of specific cognitive deficits in this condition.     

Role of NF-kappaB and p38 MAP kinase signaling pathways in the lipopolysaccharide-dependent activation of heme oxygenase-1 gene expression

Heme oxygenase (HO)-1 is the inducible isoform of the rate-limiting enzyme of heme degradation, which is up-regulated by a host of stress stimuli. The bacterial cell membrane component lipopolysaccharide (LPS) is a prototypical activator of monocytic cells. Here, it is shown that LPS induced the endogenous HO-1 gene expression in RAW264.7 monocytic cells. To investigate the molecular mechanisms of HO-1 gene induction by LPS, we performed transfection experiments with reporter gene constructs containing sequences of the proximal rat HO-1 gene promoter. Deletion and mutation analysis indicated that a cyclic AMP response element/activator protein-1 site (-664/-657), but not an E-box motif (-47/-42), played a major role for LPS-dependent HO-1 gene induction. Up-regulation of HO-1 promoter activity by LPS was decreased by pharmacological nuclear factor-kappaB (NF-kappaB) inhibitors and by cotransfected expression vectors with dominant negative isoforms of NF-kappaB-inducing kinase, inhibitor of NF-kappaB (IkappaB) kinase beta, and IkappaBalpha. Moreover, the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 and overexpressed dominant negative p38beta decreased, whereas dominant negative p38delta increased, LPS-dependent induction of HO-1 gene expression. The results suggest that the NF-kappaB and p38 MAPK signaling pathways mediate the LPS-dependent induction of HO-1 gene expression via DNA sequences of the proximal promoter region.     

Desaturation and heme elevation during COVID-19 infection: A potential prognostic factor of heme oxygenase-1

Increased heme levels, anemia, and desaturation occur during infection. We aimed to compare the levels of heme, heme oxygenase-1 (HO-1), ferritin, and bilirubin in coronavirus disease 2019 (COVID-19) patients at different saturation levels. Heme and HO-1 enzyme levels significantly increased in the low SpO₂ group, but further studies are required.     

Regulation of heme oxygenase-1 by redox signals involving nitric oxide

Heme oxygenase-1 (HO-1) is an inducible stress protein the expression of which can be markedly augmented in eukaryotes by a wide range of substances that cause a transient change in the cellular redox state. The importance of this protein in physiology and disease is underlined by the versatility of HO-1 inducers and the functional role attributed to HO-1 products (carbon monoxide and bilirubin) in conditions that are associated with moderate or severe cellular stress. An intriguing aspect is the recent evidence showing that nitric oxide, a ubiquitous signaling molecule, finely modulates the activation of HO-1 expression. As the effects of oxidative stress on the regulation of the HO-1 gene have been well established and characterized, this review will focus on the biological relevance of redox signals involving nitric oxide and reactive nitrogen species that lead to up-regulation of the HO-1 pathway, with particular emphasis on vascular tissues and the cardiovascular system.