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The liver is frequently exposed to insults, including toxic chemicals and alcohol, viral infection or metabolic overload. Although it can fully regenerate after acute injury, chronic liver damage causes liver fibrosis and cirrhosis, which can result in complete liver failure. In this study, we demonstrate that the NF-E2-related factor 2 (Nrf2) transcription factor protects the liver from acute and chronic toxin-mediated damage. Repair of the liver injury that occurs after a single treatment with the hepatotoxin carbon tetrachloride (CCl 4 ) was severely delayed in Nrf2-deficient mice. The defect in repair was accompanied by an enhanced and prolonged inflammatory and profibrotic response. After long-term CCl 4 treatment, liver fibrosis was strongly aggravated in the Nrf2 knockout mice and inflammation was enhanced. We demonstrate that these abnormalities are at least in part due to the reduced expression of known and novel Nrf2 target genes in hepatocytes, which encode enzymes involved in the detoxification of CCl 4 and its metabolites. These results suggest that activation of Nrf2 may be a novel strategy to prevent or ameliorate toxin-induced liver injury and fibrosis.

This study demonstrated a reproducible protocol for reprogramming blood cells into transgene‐free induced pluripotent stem cells (iPSCs) using Sendai viral vectors. Creation of iPSCs, without integration of exogenous DNA, helps preserve genomic integrity and fosters the development of therapeutic‐grade stem cells for regenerative medicine. The discovery of induced pluripotent stem cells (iPSCs) holds great promise for regenerative medicine since it is possible to produce patient‐specific pluripotent stem cells from affected individuals for potential autologous treatment. Using nonintegrating cytoplasmic Sendai viral vectors, we generated iPSCs efficiently from adult mobilized CD34+ and peripheral blood mononuclear cells. After 5–8 passages, the Sendai viral genome could not be detected by real‐time quantitative reverse transcription‐polymerase chain reaction. Using the spin embryoid body method, we showed that these blood cell‐derived iPSCs could efficiently be differentiated into hematopoietic stem and progenitor cells without the need of coculture with either mouse or human stromal cells. We obtained up to 40% CD34+ of which ∼25% were CD34+/CD43+ hematopoietic precursors that could readily be differentiated into mature blood cells. Our study demonstrated a reproducible protocol for reprogramming blood cells into transgene‐free iPSCs by the Sendai viral vector method. Maintenance of the genomic integrity of iPSCs without integration of exogenous DNA should allow the development of therapeutic‐grade stem cells for regenerative medicine.

Mechanical ventilation (MV) elicits complex and clinically relevant cellular responses in the lungs. The current study was designed to define the role of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), a major regulator of the cellular antioxidant defense system, in the pulmonary response to MV. Nrf2 activity was quantified in ventilated isolated perfused mouse lungs (IPL). Regulation of amphiregulin (AREG) was investigated in BEAS-2B cells with inactivated Nrf2 or Keap1, the inhibitor of Nrf2, using a luciferase vector with AREG promoter. AREG-dependent Nrf2 activity was examined in BEAS-2B cells, murine precision-cut lung slices (PCLS), and IPL. Finally, Nrf2 knockout and wild-type mice were ventilated to investigate the interplay between Nrf2 and AREG during MV in vivo. Lung functions and inflammatory parameters were measured. Nrf2 was activated in a ventilation-dependent manner. The knockdown of Nrf2 and Keap1 via short hairpin RNA in BEAS-2B cells and an EMSA with lung tissue revealed that AREG is regulated by Nrf2. Conversely, AREG application induced a significant Nrf2 activation in BEAS-2B cells, PCLS, and IPL. The signal transduction of ventilation-induced Nrf2 activation was shown to be p38 MAP kinase-dependent. In vivo ventilation experiments indicated that AREG is regulated by Nrf2 during MV. We conclude that Areg expression is regulated by Nrf2. During high-pressure ventilation, Nrf2 becomes activated and induces AREG, leading to a positive feedback loop between Nrf2 and AREG, which involves the p38 MAPK and results in the expression of cytoprotective genes.

Individuals homozygous for the C-C chemokine receptor type 5 gene with 32-bp deletions (CCR5Δ32) are resistant to HIV-1 infection. In this study, we generated induced pluripotent stem cells (iPSCs) homozygous for the naturally occurring CCR5Δ32 mutation through genome editing of wild-type iPSCs using a combination of transcription activator-like effector nucleases (TALENs) or RNA-guided clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 together with the piggyBac technology. Remarkably, TALENs or CRISPR-Cas9–mediated double-strand DNA breaks resulted in up to 100% targeting of the colonies on one allele of which biallelic targeting occurred at an average of 14% with TALENs and 33% with CRISPR. Excision of the piggyBac using transposase seamlessly reproduced exactly the naturally occurring CCR5Δ32 mutation without detectable exogenous sequences. We differentiated these modified iPSCs into monocytes/macrophages and demonstrated their resistance to HIV-1 challenge. We propose that this strategy may provide an approach toward a functional cure of HIV-1 infection.

Oxidative stress has been implicated in the etiology of Parkinson's disease (PD) and in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) animal model of PD. It is known that under conditions of oxidative stress, the transcription factor NF-E2-related factor (Nrf2) binds to antioxidant response element (ARE) to induce antioxidant and phase II detoxification enzymes. To investigate the role of Nrf2 in the process of MPTP-induced toxicity, mice expressing the human placental alkaline phosphatase (hPAP) gene driven by a promoter containing a core ARE sequence (ARE-hPAP) were used. ARE-hPAP mice were injected (30 mg/kg) once per day for 5 days and killed 7 days after the last MPTP injection. In response to this design, ARE-dependent gene expression was decreased in striatum whereas it was increased in substantia nigra. The same MPTP protocol was applied in Nrf2⁺/⁺ and Nrf2⁻/⁻ mice; Nrf2 deficiency increases MPTP sensitivity. Furthermore, we evaluated the potential for astrocytic Nrf2 overexpression to protect from MPTP toxicity. Transgenic mice with Nrf2 under control of the astrocyte-specific promoter for the glial fribillary acidic protein (GFAP-Nrf2) on both a Nrf2⁺/⁺ and Nrf2⁻/⁻ background were administered MPTP. In the latter case, only the astrocytes expressed Nrf2. Independent of background, MPTP-mediated toxicity was abolished in GFAP-Nrf2 mice. These striking results indicate that Nrf2 expression restricted to astrocytes is sufficient to protect against MPTP and astrocytic modulation of the Nrf2-ARE pathway is a promising target for therapeutics aimed at reducing or preventing neuronal death in PD.

The innovation of reprogramming somatic cells to induced pluripotent stem cells provides a possible new approach to treat β-thalassemia and other genetic diseases such as sickle cell anemia. Induced pluripotent stem (iPS) cells can be made from these patients' somatic cells and the mutation in the β-globin gene corrected by gene targeting, and the cells differentiated into hematopoietic cells to be returned to the patient. In this study, we reprogrammed the skin fibroblasts of a patient with homozygous β° thalassemia into iPS cells, and showed that the iPS cells could be differentiated into hematopoietic cells that synthesized hemoglobin. Prenatal diagnosis and selective abortion have been effective in decreasing the number of β-thalassemia births in some countries that have instituted carrier screening and genetic counseling. To make use of the cells from the amniotic fluid or chorionic villus sampling that are used for prenatal diagnosis, we also showed that these cells could be reprogrammed into iPS cells. This raises the possibility of providing a new option following prenatal diagnosis of a fetus affected by a severe illness. Currently, the parents would choose either to terminate the pregnancy or continue it and take care of the sick child after birth. The cells for prenatal diagnosis can be converted into iPS cells for treatment in the perinatal periods. Early treatment has the advantage of requiring much fewer cells than adult treatment, and can also prevent organ damage in those diseases in which damage can begin in utero or at an early age.

Objectives Increasing evidence suggests that oxidative stress may play a key role in joint destruction due to rheumatoid arthritis (RA). The aim of this study was to elucidate the role of nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor that maintains the cellular defence against oxidative stress, in RA. Methods The activation status of Nrf2 was assessed in synovial tissue from patients with RA using immunohistochemistry. Antibody-induced arthritis (AIA) was induced in Nrf2-knockout and Nrf2-wild-type control mice. The severity of cartilage destruction was evaluated using a damage score. The extent of oxidative stress, the activation state of Nrf2 and the expression level of Nrf2 target genes were analysed by immunhistological staining. The expression of vascular endothelial growth factor (VEGF)-A was examined on mRNA and protein using the Luminex technique. A Xenogen imaging system was used to measure Nrf2 activity in an antioxidant response element-luciferase transgenic mouse during AIA. Results Nrf2 was activated in the joints of arthritic mice and of patients with RA. Nrf2-knockout mice had more severe cartilage injuries and more oxidative damage, and the expression of Nrf2 target genes was enhanced in Nrf2-wild-type but not in knockout mice during AIA. Both VEGF-A mRNA and protein expression was upregulated in Nrf2-knockout mice during AIA. An unexpected finding was the number of spontaneously fractured bones in Nrf2-knockout mice with AIA. Conclusion These results provide strong evidence that oxidative stress is significantly involved in cartilage degradation in experimental arthritis, and indicate that the presence of a functional Nrf2 gene is a major requirement for limiting cartilage destruction.

Nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) is a transcription factor which regulates the expression of many cytoprotective genes. In the present study, we found that the expression of Nrf2 was suppressed in prostate tumor of the Transgenic Adenocarcinoma of Mouse Prostate (TRAMP) mice. Similarly, the expression of Nrf2 and the induction of NQO1 were also substantially suppressed in tumorigenic TRAMP C1 cells but not in non-tumorigenic TRAMP C3 cells. Examination of the promoter region of the mouse Nrf2 gene identified a CpG island, which was methylated at specific CpG sites in prostate TRAMP tumor and in TRAMP C1 cells but not in normal prostate or TRAMP C3 cells, as shown by bisulfite genomic sequencing. Reporter assays indicated that methylation of these CpG sites dramatically inhibited the transcriptional activity of the Nrf2 promoter. Chromatin immunopreceipitation (ChIP) assays revealed increased binding of the methyl-CpG-binding protein 2 (MBD2) and trimethyl-histone H3 (Lys9) proteins to these CpG sites in the TRAMP C1 cells as compared to TRAMP C3 cells. In contrast, the binding of RNA Pol II and acetylated histone H3 to the Nrf2 promoter was decreased. Furthermore, treatment of TRAMP C1 cells with DNA methyltransferase (DNMT) inhibitor 5-aza-2'-deoxycytidine (5-aza) and histone deacetylase (HDAC) inhibitor trichostatin A (TSA) restored the expression of Nrf2 as well as the induction of NQO1 in TRAMP C1 cells. Taken together, these results indicate that the expression of Nrf2 is suppressed epigenetically by promoter methylation associated with MBD2 and histone modifications in the prostate tumor of TRAMP mice. Our present findings reveal a novel mechanism by which Nrf2 expression is suppressed in TRAMP prostate tumor, shed new light on the role of Nrf2 in carcinogenesis and provide potential new directions for the detection and prevention of prostate cancer.

VEGF and angiopoietin-1 (Ang1) are two major angiogenic factors being investigated for the treatment of myocardial infarction (MI). Targeting VEGF and Ang1 expression in the ischemic myocardium can increase their local therapeutic effects and reduce possible adverse effects. Adeno-associated viral vectors (AAVs) expressing cardiac-specific and hypoxia-inducible VEGF [AAV-myosin light chain-2v (MLC)VEGF] and Ang1 (AAV-MLCAng1) were coinjected (VEGF/Ang1 group) into six different sites of the porcine myocardium at the peri-infarct zone immediately after ligating the left descending coronary artery. An identical dose of AAV-Cytomegalovirus (CMV)LacZ or saline was injected into control animals. AAV genomes were detected in the liver in addition to the heart. RT-PCR, Western blotting, and ELISA analyses showed that VEGF and Ang1 were predominantly expressed in the myocardium in the infarct core and border of the infarct heart. Gated single-photon emission computed tomography analyses showed that the VEGF/Ang1 group had better cardiac function and myocardial perfusion at 8 wk than at 2 wk after vector injection. Compared with the saline and LacZ controls, the VEGF/Ang1 group expressed higher phosphorylated Akt and Bcl-xL, less Caspase-3 and Bad, and had higher vascular density, more proliferating cardiomyocytes, and less apoptotic cells in the infarct and peri-infarct zones. Thus, cardiac-specific and hypoxia-induced coexpression of VEGF and Ang1 improves the perfusion and function of porcine MI heart through the induction of angiogenesis and cardiomyocyte proliferation, activation of prosurvival pathways, and reduction of cell apoptosis.

The liver is frequently challenged by surgery‐induced metabolic overload, viruses or toxins, which induce the formation of reactive oxygen species. To determine the effect of oxidative stress on liver regeneration and to identify the underlying signaling pathways, we studied liver repair in mice lacking the Nrf2 transcription factor. In these animals, expression of several cytoprotective enzymes was reduced in hepatocytes, resulting in oxidative stress. After partial hepatectomy, liver regeneration was significantly delayed. Using in vitro and in vivo studies, we identified oxidative stress‐mediated insulin/insulin‐like growth factor resistance as an underlying mechanism. This deficiency impaired the activation of p38 mitogen‐activated kinase, Akt kinase and downstream targets after hepatectomy, resulting in enhanced death and delayed proliferation of hepatocytes. Our results reveal novel roles of Nrf2 in the regulation of growth factor signaling and in tissue repair. In addition, they provide new insight into the mechanisms underlying oxidative stress‐induced defects in liver regeneration. These findings may provide the basis for the development of new strategies to improve regeneration in patients with acute or chronic liver damage.