Fumarates promote cytoprotection of central nervous system cells against oxidative stress via the nuclear factor (erythroid-derived 2)-like 2 pathway

Oxidative stress is central to the pathology of several neurodegenerative diseases, including multiple sclerosis, and therapeutics designed to enhance antioxidant potential could have clinical value. The objective of this study was to characterize the potential direct neuroprotective effects of dimethyl fumarate (DMF) and its primary metabolite monomethyl fumarate (MMF) on cellular resistance to oxidative damage in primary cultures of central nervous system (CNS) cells and further explore the dependence and function of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway in this process. Treatment of animals or primary cultures of CNS cells with DMF or MMF resulted in increased nuclear levels of active Nrf2, with subsequent up-regulation of canonical antioxidant target genes. DMF-dependent up-regulation of antioxidant genes in vivo was lost in mice lacking Nrf2 [Nrf2(-/-)]. DMF or MMF treatment increased cellular redox potential, glutathione, ATP levels, and mitochondrial membrane potential in a concentration-dependent manner. Treating astrocytes or neurons with DMF or MMF also significantly improved cell viability after toxic oxidative challenge in a concentration-dependent manner. This effect on viability was lost in cells that had eliminated or reduced Nrf2. These data suggest that DMF and MMF are cytoprotective for neurons and astrocytes against oxidative stress-induced cellular injury and loss, potentially via up-regulation of an Nrf2-dependent antioxidant response. These data also suggest DMF and MMF may function through improving mitochondrial function. The clinical utility of DMF in multiple sclerosis is being explored through phase III trials with BG-12, which is an oral therapeutic containing DMF as the active ingredient.     

HSP60和NRF2在透明细胞性肾细胞癌中的表达及临床价值

目的研究透明细胞性肾细胞癌(ccRCC)中热休克蛋白60(HSP60)及核因子E2相关因子2(NRF2)的表达及临床意义。方法选取2017年3月至2019年3月在安康市中心医院诊治的89例ccRCC患者为研究对象,应用荧光定量聚合酶链反应(qPCR)及免疫组织化学检测癌组织及癌旁组织中HSP60、NRF2的表达。统计分析ccRCC中HSP60、NRF2的表达与临床病理特征关系。采用Spearmen秩相关分析HSP60与NRF2 mRNA表达的相关性,Kaplan-Meier生存分析(Log-Rank检验)ccRCC中HSP60、NRF2的表达与患者生存预后的关系,单因素和多因素COX比例风险模型分析影响ccRCC患者生存预后的危险因素。结果ccRCC癌组织HSP60的相对表达量(0.483±0.112)明显低于癌旁组织(1.227±0.265),差异有统计学意义(t=24.397,P<0.001),而NRF2 mRNA的相对表达量(1.725±0.285)明显高于癌旁组织(0.551±0.101),差异有统计学意义(t=36.629,P<0.001)。ccRCC癌组织中HSP60与NRF2的表达呈明显负相关(r=-0.520,P<0.001)。ccRCC癌组织中HSP60、NRF2的表达与肿瘤分期、远处转移及淋巴结转移有关(χ²=11.749、24.815、45.762,17.225、21.913、7.061,均P<0.05)。HSP60低表达组3年生存率为41.5%(17/41),明显高于HSP60高表达组的3年生存率93.2%(41/44),差异有统计学意义(χ²=30.79,P<0.001);HSP60低表达组平均生存时间为(23.5±6.1)个月,明显高于HSP60高表达组的平均生存时间(28.2±6.4)个月,差异有统计学意义(t=3.460,P<0.001)。NRF2低表达组3年生存率为95.2%(40/42),明显高于NRF2高表达组的3年生存率41.9%(18/43),差异有统计学意义(χ²=30.79,P<0.001),HSP60低表达组平均生存时间为(29.1±6.2)个月,明显高于HSP60高表达组的平均生存时间(22.4±6.3)个月,差异有统计学意义(χ²=4.941,P<0.001)。多因素Cox回归分析结果显示,ccRCC组织中HSP60低表达、NRF2高表达、肿瘤分期Ⅲ~Ⅳ期是影响ccRCC患者不良预后的独立危险因素。结论ccRCC中HSP60表达降低,而NRF2表达升高,二者表达与肿瘤分期、淋巴结转移及远处转移有关,有望成为提示ccRCC预后的肿瘤标志物。     

Oxidative stress and dysfunctional NRF2 underlie pachyonychia congenita phenotypes

Palmoplantar keratoderma (PPK) are debilitating lesions that arise in individuals with pachyonychia congenita (PC) and feature upregulation of danger-associated molecular patterns and skin barrier regulators. The defining features of PC-associated PPK are reproduced in mice null for keratin 16 (Krt16), which is commonly mutated in PC patients. Here, we have shown that PPK onset is preceded by oxidative stress in footpad skin of Krt16^–/– mice and correlates with an inability of keratinocytes to sustain nuclear factor erythroid–derived 2 related factor 2–dependent (NRF2-dependent) synthesis of the cellular antioxidant glutathione (GSH). Additionally, examination of plantar skin biopsies from individuals with PC confirmed the presence of high levels of hypophosphorylated NRF2 in lesional tissue. In Krt16^–/– mice, genetic ablation of Nrf2 worsened spontaneous skin lesions and accelerated PPK development in footpad skin. Hypoactivity of NRF2 in Krt16^–/– footpad skin correlated with decreased levels or activity of upstream NRF2 activators, including PKCδ, receptor for activated C kinase 1 (RACK1), and p21. Topical application of the NRF2 activator sulforaphane to the footpad of Krt16^–/– mice prevented the development of PPK and normalized redox balance via regeneration of GSH from existing cellular pools. Together, these findings point to oxidative stress and dysfunctional NRF2 as contributors to PPK pathogenesis, identify K16 as a regulator of NRF2 activation, and suggest that pharmacological activation of NRF2 should be further explored for PC treatment.     

Transcription factor NRF2 regulates miR-1 and miR-206 to drive tumorigenesis

The mechanisms by which deregulated nuclear factor erythroid-2–related factor 2 (NRF2) and kelch-like ECH-associated protein 1 (KEAP1) signaling promote cellular proliferation and tumorigenesis are poorly understood. Using an integrated genomics and ¹³C-based targeted tracer fate association (TTFA) study, we found that NRF2 regulates miR-1 and miR-206 to direct carbon flux toward the pentose phosphate pathway (PPP) and the tricarboxylic acid (TCA) cycle, reprogramming glucose metabolism. Sustained activation of NRF2 signaling in cancer cells attenuated miR-1 and miR-206 expression, leading to enhanced expression of PPP genes. Conversely, overexpression of miR-1 and miR-206 decreased the expression of metabolic genes and dramatically impaired NADPH production, ribose synthesis, and in vivo tumor growth in mice. Loss of NRF2 decreased the expression of the redox-sensitive histone deacetylase, HDAC4, resulting in increased expression of miR-1 and miR-206, and not only inhibiting PPP expression and activity but functioning as a regulatory feedback loop that repressed HDAC4 expression. In primary tumor samples, the expression of miR-1 and miR-206 was inversely correlated with PPP gene expression, and increased expression of NRF2-dependent genes was associated with poor prognosis. Our results demonstrate that microRNA-dependent (miRNA-dependent) regulation of the PPP via NRF2 and HDAC4 represents a novel link between miRNA regulation, glucose metabolism, and ROS homeostasis in cancer cells.     

糖尿病心肌病及潜在的干预

糖尿病心肌病是严重的心血管并发症之一,氧化应激与糖尿病心肌病的发病密切相关,因此,抗氧化治疗一直是糖尿病心肌病治疗领域的热点。金属硫蛋白（MT）作为内源性高效的非特异性的抗氧化剂,Nrf2作为抗氧化基因的重要调控因子,都在抗氧化过程中都发挥了重要作用。如何应用安全有效的MT和Nrf2诱导剂来清除多种活性自由基有效地预防糖尿病性心肌病,在防治糖尿病心血管并发症方面将有广阔的应用前景。     

Dimethyl fumarate induces apoptosis of hematopoietic tumor cells via inhibition of NF-κB nuclear translocation and down-regulation of Bcl-xL and XIAP

Dimethyl fumarate (DMF) is a fumaric acid ester that is used to treat psoriasis and multiple sclerosis. Recently, DMF was found to exhibit anti-tumor effects. However, the molecular mechanisms underlying these effects have not been elucidated. In this study, we investigated the mechanism of DMF-induced apoptosis in different human hematopoietic tumor cell lines. We found that DMF induced apoptosis in different human hematopoietic tumor cell lines but it did not affect the normal human B lymphocyte cell line RPMI 1788. We also observed a concurrent increase in caspase-3 activity and in the number of Annexin-V-positive cells. Furthermore, an examination of the survival signals, which are activated by apoptotic stimuli, revealed that DMF significantly inhibited nuclear factor-κB (NF-κB) p65 nuclear translocation. In addition, DMF suppressed B-cell lymphoma extra-large (Bcl-xL) and X-linked inhibitor of apoptosis (XIAP) expression whereas Bcl-2, survivin, Bcl-2-associated X protein (Bax), and Bim levels did not change. These results indicated that DMF induced apoptosis by suppressing NF-κB activation, and Bcl-xL and XIAP expression. These findings suggested that DMF might have potential as an anticancer agent that could be used in combination therapy with other anticancer drugs for the treatment of human hematopoietic tumors.     

NRF2-mediated Notch pathway activation enhances hematopoietic reconstitution following myelosuppressive radiation

A nuclear disaster may result in exposure to potentially lethal doses of ionizing radiation (IR). Hematopoietic acute radiation syndrome (H-ARS) is characterized by severe myelosuppression, which increases the risk of infection, bleeding, and mortality. Here, we determined that activation of nuclear factor erythroid-2–related factor 2 (NRF2) signaling enhances hematopoietic stem progenitor cell (HSPC) function and mitigates IR-induced myelosuppression and mortality. Augmenting NRF2 signaling in mice, either by genetic deletion of the NRF2 inhibitor Keap1 or by pharmacological NRF2 activation with 2-trifluoromethyl-2′-methoxychalone (TMC), enhanced hematopoietic reconstitution following bone marrow transplantation (BMT). Strikingly, even 24 hours after lethal IR exposure, oral administration of TMC mitigated myelosuppression and mortality in mice. Furthermore, TMC administration to irradiated transgenic Notch reporter mice revealed activation of Notch signaling in HSPCs and enhanced HSPC expansion by increasing Jagged1 expression in BM stromal cells. Administration of a Notch inhibitor ablated the effects of TMC on hematopoietic reconstitution. Taken together, we identified a mechanism by which NRF2-mediated Notch signaling improves HSPC function and myelosuppression following IR exposure. Our data indicate that targeting this pathway may provide a countermeasure against the damaging effects of IR exposure.     

富马酸二甲酯对急性T淋巴细胞白血病影响的研究

目的:探讨富马酸二甲酯(DMF)对急性T淋巴细胞白血病的影响及潜在的作用机制,为临床治疗急性T淋巴细胞白血病提供实验基础和理论依据.方法:用不同浓度DMF处理Jurkat细胞24 h,然后采用流式细胞术检测Ki67+的Jurkat细胞比例和绝对计数;同时采用Western blot方法检测DMF处理24 h之后,Jur...     

Nrf2及其信号通路在脓毒症相关脏器损伤中的研究进展

脓毒症(sepsis)是重症监护病房(ICU)患者死亡的常见病因,治疗难度大,且预后较差,给全球医疗卫生系统造成巨大经济负担。然而针对脓毒症的治疗仍缺乏有效的防治手段。核转录因子-E2相关因子2(Nrf2)是抗氧化应激体系中的关键转录因子,它通过调节抗氧化反应原(ARE)介导的抗氧化酶和Ⅱ相解毒酶等的表达,在脓毒症治疗中发挥关键作用。本文总结了Nrf2相关信号通路及其在脓毒症器官损伤中的最新研究进展,以期为临床治疗脓毒症提供新的治疗策略。     

NRF2 mitigates radiation-induced hematopoietic death

Fractionated, high-dose total body irradiation (TBI) is used therapeutically to myeloablate and immune suppress patients undergoing hematopoietic stem cell (HSC) transplantation. Acute exposure to ionizing radiation can have fatal effects on the hematopoietic and immune systems. Currently, therapies aimed at ameliorating ionizing radiation–associated toxicities are limited. In the February 2014 issue of the JCI, Kim and colleagues demonstrated that induction of nuclear factor erythroid 2–related factor 2 (NRF2) enhances HSC regeneration and increases survival following ionizing radiation exposure in mice. The results of this study suggest that NRF2 is a novel potential target for the development of therapeutics aimed at mitigating the toxicities of ionizing radiation exposure.     

The Keap1–Nrf2–ARE Pathway As a Potential Preventive and Therapeutic Target: An Update

The Keap1–Nrf2–ARE ((Kelch‐like ECH‐Associating protein 1) nuclear factor erythroid 2 related factor 2‐antioxidant response element) pathway is one of the most important defense mechanisms against oxidative and/or electrophilic stresses, and it is closely associated with inflammatory diseases, including cancer, neurodegenerative diseases, cardiovascular diseases, and aging. In recent years, progress has been made in strategies aimed at modulating the Keap1–Nrf2–ARE pathway. The Nrf2 activator DMF (Dimethylfumarates) has been approved by the FDA as a new first‐line oral drug to treat patients with relapsing forms of multiple sclerosis, while a phase 3 study of another promising candidate, CDDO‐Me, was terminated for safety reasons. Directly inhibiting Keap1–Nrf2 protein–protein interactions as a novel Nrf2‐modulating strategy has many advantages over using electrophilic Nrf2 activators. The development of Keap1–Nrf2 protein–protein interaction inhibitors has become a topic of intense research, and potent inhibitors of this target have been identified. In addition, inhibiting Nrf2 activity has attracted an increasing amount of attention because it may provide an alternative cancer therapy. This review summarizes the molecular mechanisms and biological functions of the Keap1–Nrf2–ARE system. The main focus of this review is on recent progress in studies of agents that target the Keap1–Nrf2–ARE pathway and the therapeutic applications of such agents.     

神经再生素促海马神经元生长的基因芯片研究

目的:探索中药“神经再生素”对海马神经元生长的作用及生物学机制。方法:采用海马神经元培养及基因芯片技术,中药组加入神经再生素1μg/ ml ,对照组加入等量基础培养液。培养6 h后,观察海马神经元突起长度,并提取2组的神经元总RNA,经反转录分别用荧光标记成cDNA探针,与大鼠全基因组芯片杂交,芯片扫描,后行GCOS软件处理。结果:中药组细胞突起长度(18μm)明显长于对照组(12μm)(P<0 .01)。在基因芯片15866条基因中,248条基因上调,316条基因下调,这些基因有细胞组份、生物过程生长代谢调控因子、信号转导分子、凋亡调控因子、免疫蛋白、酶等。结论:中药“神经再生素”可促海马神经元生长。差异表达的基因为寻找药物作用的基因靶点提供了基础。     

Oxidative stress fuels Trypanosoma cruzi infection in mice

Oxidative damage contributes to microbe elimination during macrophage respiratory burst. Nuclear factor, erythroid-derived 2, like 2 (NRF2) orchestrates antioxidant defenses, including the expression of heme-oxygenase-1 (HO-1). Unexpectedly, the activation of NRF2 and HO-1 reduces infection by a number of pathogens, although the mechanism responsible for this effect is largely unknown. We studied Trypanosoma cruzi infection in mice in which NRF2/HO-1 was induced with cobalt protoporphyrin (CoPP). CoPP reduced parasitemia and tissue parasitism, while an inhibitor of HO-1 activity increased T. cruzi parasitemia in blood. CoPP-induced effects did not depend on the adaptive immunity, nor were parasites directly targeted. We also found that CoPP reduced macrophage parasitism, which depended on NRF2 expression but not on classical mechanisms such as apoptosis of infected cells, induction of type I IFN, or NO. We found that exogenous expression of NRF2 or HO-1 also reduced macrophage parasitism. Several antioxidants, including NRF2 activators, reduced macrophage parasite burden, while pro-oxidants promoted it. Reducing the intracellular labile iron pool decreased parasitism, and antioxidants increased the expression of ferritin and ferroportin in infected macrophages. Ferrous sulfate reversed the CoPP-induced decrease in macrophage parasite burden and, given in vivo, reversed their protective effects. Our results indicate that oxidative stress contributes to parasite persistence in host tissues and open a new avenue for the development of anti-T. cruzi drugs.     

B cell activating factor in obesity is regulated by oxidative stress in adipocytes

Adipose tissue functions as a key endocrine organ by releasing multiple bioactive substances, and plays a key role in the integration of systemic metabolism. We have previously shown that B cell activating factor is produced mainly in visceral adipose tissue and affects insulin sensitivity in obese individuals. In this study, we identified the signals that lead to production of B cell activating factor in adipocytes. 3T3-L1 and C3H/10T 1/2-clone 8 cells showed increased B cell activating factor expression upon exposure to hydrogen peroxide, and these changes were inhibited by treatment with the antioxidant N-acetyl-cysteine. B cell activating factor levels in both serum and visceral adipose tissue were increased in high fat diet-fed mice, and these increases were correlated with oxidative stress. In addition, serum BAFF levels in high fat diet-fed mice were reduced by N-acetyl-cysteine treatment. We also found that oxidative stress-induced B cell activating factor expression in adipocytes was regulated by NF-κB activation. These data indicate that control of the redox state in visceral adipose tissue is a potentially useful target for treating metabolic syndromes through regulation of adipokine production.     

Curcumin and its analogues: Potential anticancer agents

This review chronicles the exploration of the curcumin in terms of development of analogues for the anticancer activity over the last century. Curcumin is a natural phytochemical obtained from dried root and rhizome of Turmeric (Curcuma Longa). It has been shown to interfere with multiple cell signaling pathways, including apoptosis (activation of caspases and downregulation of antiapoptotic gene products), proliferation (HER‐2, EGFR, and AP‐1), angiogenesis (VEGF), and inflammation (NF‐κB, TNF, IL‐6, IL‐1, COX‐2, and 5‐LOX). In the last decade it has been much explored and various synthetic analogues have been prepared and evaluated for various pharmacological activities. Most of the analogues have shown very good anticancer activity in various models and various cell lines. However, some analogues have also shown antioxidant, anti‐HIV, antimutagenic, antiangiogenic, antimalarial, antitubercular, antiandrogenic, COX inhibitory activities. Few analogues have shown very potent results and may be considered as clinical candidates for the development of future anticancer agent. This review contains 728 curcumin analogues and covers the literature from 1815 to mid 2009 and 93 references are cited. © 2009 Wiley Periodicals, Inc. Med Res Rev, 30, No. 5, 818–860, 2010