Jun dimerization protein 2 is a critical component of the Nrf2/MafK complex regulating the response to ROS homeostasis

Di-n-butyl phthalate promotes the neural differentiation of mouse embryonic stem cells through neurogenic differentiation 1

An understanding of the risk of gene deletion and mutation posed by endocrine-disrupting chemicals (EDCs) is necessary for the identification of etiological reagents for many human diseases. Therefore, the characterization of the genetic traits caused by developmental exposure to EDCs is an important research subject. A new regenerative approach using embryonic stem cells (ESCs) holds promise for the development of stem-cell-based therapies and the identification of novel therapeutic agents against human diseases. Here, we focused on the characterization of the genetic traits and alterations in pluripotency/stemness triggered by phthalate ester derivatives. Regarding their in vitro effects, we reported the abilities of ESCs regarding proliferation, cell-cycle control, and neural ectoderm differentiation. The expression of their stemness-related genes and their genetic changes toward neural differentiation were examined, which led to the observation that the tumor suppressor gene product p53/retinoblastoma protein 1 and its related cascades play critical functions in cell-cycle progression, cell death, and neural differentiation. In addition, the expression of neurogenic differentiation 1 was affected by exposure to di-n-butyl phthalate in the context of cell differentiation into neural lineages. The nervous system is one of the most sensitive tissues to exposure to phthalate ester derivatives. The present screening system provides a good tool for studying the mechanisms underlying the effects of EDCs on the developmental regulation of humans and rodents, especially on the neuronal development of ESCs.

Heterogeneity of Phase II Enzyme Ligands on Controlling the Progression of Human Gastric Cancer Organoids as Stem Cell Therapy Model

Gastric cancer (GC) organoids are frequently used to examine cell proliferation and death as well as cancer development. Invasion/migration assay, xenotransplantation, and reactive oxygen species (ROS) production were used to examine the effects of antioxidant drugs, including perillaldehyde (PEA), cinnamaldehyde (CA), and sulforaphane (SFN), on GC. PEA and CA repressed the proliferation of human GC organoids, whereas SFN enhanced it. Caspase 3 activities were also repressed on treatment with PEA and CA. Furthermore, the tumor formation and invasive activities were repressed on treatment with PEA and CA, whereas they were enhanced on treatment with SFN. These results in three-dimensional (3D)-GC organoids showed the different cancer development of phase II enzyme ligands in 2D-GC cells. ROS production and the expression of TP53, nuclear factor erythroid 2-related factor (NRF2), and Jun dimerization protein 2 were also downregulated on treatment with PEA and CA, but not SFN. NRF2 knockdown reversed the effects of these antioxidant drugs on the invasive activities of the 3D-GC organoids. Moreover, ROS production was also inhibited by treatment with PEA and CA, but not SFN. Thus, NRF2 plays a key role in the differential effects of these antioxidant drugs on cancer progression in 3D-GC organoids. PEA and CA can potentially be new antitumorigenic therapeutics for GC.

Jdp2 is a spatiotemporal transcriptional activator of the AhR via the Nrf2 gene battery

BACKGROUND

Crosstalk between the aryl hydrocarbon receptor (AhR) and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) signaling is called the "AhR-Nrf2 gene battery", which works synergistically in detoxification to support cell survival. Nrf2-dependent phase II gene promoters are controlled by coordinated recruitment of the AhR to adjacent dioxin responsive element (DRE) and Nrf2 recruitment to the antioxidative response element (ARE). The molecular interaction between AhR and Nrf2 members, and the regulation of each target, including phase I and II gene complexes, and their mediators are poorly understood.

METHODS

Knockdown and forced expression of AhR-Nrf2 battery members were used to examine the molecular interactions between the AhR-Nrf2 axis and AhR promoter activation. Sequential immunoprecipitation, chromatin immunoprecipitation, and histology were used to identify each protein complex recruited to their respective cis-elements in the AhR promoter. Actin fiber distribution, cell spreading, and invasion were examined to identify functional differences in the AhR-Jdp2 axis between wild-type and Jdp2 knockout cells. The possible tumorigenic role of Jdp2 in the AhR-Nrf2 axis was examined in mutant Kras-Trp53-driven pancreatic tumors.

RESULTS

Crosstalk between AhR and Nrf2 was evident at the transcriptional level. The AhR promoter was activated by phase I ligands such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) through the AhR-Jdp2-Nrf2 axis in a time- and spatial transcription-dependent manner. Jdp2 was a bifunctional activator of DRE- and ARE-mediated transcription in response to TCDD. After TCDD exposure, Jdp2 activated the AhR promoter at the DRE and then moved to the ARE where it activated the promoter to increase reactive oxygen species (ROS)-mediated functions such as cell spreading and invasion in normal cells, and cancer regression in mutant Kras-Trp53-driven pancreatic tumor cells.

CONCLUSIONS

Jdp2 plays a critical role in AhR promoter activation through the AhR-Jdp2-Nrf2 axis in a spatiotemporal manner. The AhR functions to maintain ROS balance and cell spreading, invasion, and cancer regression in a mouse model of mutant Kras-Trp53 pancreatic cancer. These findings provide new insights into the roles of Jdp2 in the homeostatic regulation of oxidative stress and in the antioxidation response in detoxification, inflammation, and cancer progression.

Role of Nrf2 in aging, Alzheimer's and other neurodegenerative diseases

Nuclear Factor-Erythroid Factor 2 (Nrf2) is an important transcription factor that regulates the expression of large number of genes in healthy and disease states. Nrf2 is made up of 605 amino acids and contains 7 conserved regions known as Nrf2-ECH homology domains. Nrf2 regulates the expression of several key components of oxidative stress, mitochondrial biogenesis, mitophagy, autophagy and mitochondrial function in all organs of the human body, in the peripheral and central nervous systems. Mounting evidence also suggests that altered expression of Nrf2 is largely involved in aging, neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, Huntington's diseases, Amyotrophic lateral sclerosis, Stroke, Multiple sclerosis and others. The purpose of this article is to detail the essential role of Nrf2 in oxidative stress, antioxidative defense, detoxification, inflammatory responses, transcription factors, proteasomal and autophagic/mitophagic degradation, and metabolism in aging and neurodegenerative diseases. This article also highlights the Nrf2 structural and functional activities in healthy and disease states, and also discusses the current status of Nrf2 research and therapeutic strategies to treat aging and neurodegenerative diseases.

Single-cell ATAC-seq maps the comprehensive and dynamic chromatin accessibility landscape of CAR-T cell dysfunction

Chimeric antigen receptor T cells (CAR-T) therapy has achieved remarkable therapeutic success in treating a variety of hematopoietic malignancies. However, the high relapse rate and poor in vivo persistence, partially caused by CAR-T cell exhaustion, are still important barriers against CAR-T therapy. It remains largely elusive on the mechanisms of CAR-T exhaustion and how to attenuate exhaustion to achieve better therapeutic efficacy. In this study, we initially observed that CAR-T cells showed rapid differentiation and increased exhaustion after co-culture with tumor cells in vitro, and then performed single-cell ATAC-seq to depict the comprehensive and dynamic landscape of chromatin accessibility of CAR-T cells during tumor cell stimulation. Analyses of differential chromatin accessible regions and motif accessibility revealed that TFs were distinct in each cell type and reconstituted a coordinated regulatory network to drive CAR-T exhaustion. Furthermore, we performed scATAC-seq in patient-derived CAR-T cells and identified BATF and IRF4 as pivotal regulators in CAR-T cell exhaustion. Finally, knockdown of BATF or IRF4 enhanced the killing ability, inhibited exhaustion, and prolonged the persistence of CAR-T cells in vivo. Together, our study unraveled the epigenetic regulatory mechanisms of CAR-T exhaustion and provided new insights into CAR-T engineering to achieve better clinical treatment benefits.

Comparative parallel multi-omics analysis during the induction of pluripotent and trophectoderm states

Following fertilization, it is only at the 32-64-cell stage when a clear segregation between cells of the inner cell mass and trophectoderm is observed, suggesting a 'T'-shaped model of specification. Here, we examine whether the acquisition of these two states in vitro, by nuclear reprogramming, share similar dynamics/trajectories. Using a comparative parallel multi-omics analysis (i.e., bulk RNA-seq, scRNA-seq, ATAC-seq, ChIP-seq, RRBS and CNVs) on cells undergoing reprogramming to pluripotency and TSC state we show that each reprogramming system exhibits specific trajectories from the onset of the process, suggesting 'V'-shaped model. We describe in detail the various trajectories toward the two states and illuminate reprogramming stage-specific markers, blockers, facilitators and TSC subpopulations. Finally, we show that while the acquisition of the TSC state involves the silencing of embryonic programs by DNA methylation, during the acquisition of pluripotency these regions are initially defined but retain inactive by the elimination of H3K27ac.

Neuroprotective Effects and Therapeutic Potential of the Citrus Flavonoid Hesperetin in Neurodegenerative Diseases

Neurodegenerative disorders affect more than fifty million Americans each year and represent serious health threats as the population ages. Neuroinflammation and oxidative stress are critical in the onset, progression, and pathogenesis of neurodegenerative diseases such as Alzheimer’s (AD), Parkinson’s (PD), and amyotrophic lateral sclerosis (ALS). A wide range of natural compounds has been investigated because of their antioxidant, anti-inflammatory, and neuroprotective properties. The citrus flavonoid hesperetin (HPT), an aglycone of hesperidin found in oranges, mandarins, and lemons, has been extensively reported to exert neuroprotective effects in experimental models of neurogenerative diseases. This review has compiled multiple studies on HPT in both in vivo and in vitro models to study neurodegeneration. We focused on the modulatory effects of hesperetin on the release of cellular anti-inflammatory and antioxidative stress mediators. Additionally, this review discusses the hesperetin effect in maintaining the levels of microRNA (miRNA) and modulating autophagy as it relates to hesperetin’s protective mechanisms against neurodegeneration. Moreover, this review is focused on providing experimental data for hesperetin’s potential as a neuroprotective compound and discusses reported evidence that HPT crosses the blood–brain barrier. In summary, this review shows the evidence available in the literature to indicate the efficacy of hesperetin in delaying the onset of neurodegenerative diseases.

Cold atmospheric plasma differentially affects cell renewal and differentiation of stem cells and APC-deficient-derived tumor cells in intestinal organoids

Cold atmospheric plasma (CAP) treatment has been proposed as a potentially innovative therapeutic tool in the biomedical field, notably for cancer due to its proposed toxic selectivity on cancer cells versus healthy cells. In the present study, we addressed the relevance of three-dimensional organoid technology to investigate the biological effects of CAP on normal epithelial stem cells and tumor cells isolated from mouse small intestine. CAP treatment exerted dose-dependent cytotoxicity on normal organoids and induced major transcriptomic changes associated with the global response to oxidative stress, fetal-like regeneration reprogramming, and apoptosis-mediated cell death. Moreover, we explored the potential selectivity of CAP on tumor-like Apc-deficient versus normal organoids in the same genetic background. Unexpectedly, tumor organoids exhibited higher resistance to CAP treatment, correlating with higher antioxidant activity at baseline as compared to normal organoids. This pilot study suggests that the ex vivo culture system could be a relevant alternative model to further investigate translational medical applications of CAP technology.

Role of chemopreventive phytochemicals in NRF2-mediated redox homeostasis in humans

While functioning as a second messenger in the intracellular signaling, ROS can cause oxidative stress when produced in excess or not neutralized/eliminated properly. Excessive ROS production is implicated in multi-stage carcinogenesis. Our body is equipped with a defense system to cope with constant oxidative stress caused by the external insults, including redox-cycling chemicals, radiation, and microbial infection as well as endogenously generated ROS. The transcription factor, nuclear transcription factor erythroid 2-related factor 2 (NRF2) is a master switch in the cellular antioxidant signaling and plays a vital role in adaptive survival response to ROS-induced oxidative stress. Although NRF2 is transiently activated when cellular redox balance is challenged, this can be overwhelmed by massive oxidative stress. Therefore, it is necessary to maintain the NRF2-mediated antioxidant defense capacity at an optimal level. This review summarizes the natural NRF2 inducers/activators, especially those present in the plant-based diet, in relation to their cancer chemopreventive potential in humans. The molecular mechanisms underlying their stabilization or activation of NRF2 are also discussed.

[Novel Tyrosine Phosphorylation Signals in the Nucleus and on Mitotic Spindle Fibers and Lysosomes Revealed by Strong Inhibition of Tyrosine Dephosphorylation]

Protein-tyrosine phosphorylation is one of the posttranslational modifications and plays critical roles in regulating a wide variety of cellular processes, such as cell proliferation, differentiation, adhesion, migration, survival, and apoptosis. Protein-tyrosine phosphorylation is reversibly regulated by protein-tyrosine kinases and protein-tyrosine phosphatases. Strong inhibition of protein-tyrosine phosphatase activities is required to undoubtedly detect tyrosine phosphorylation. Our extremely careful usage of Na₃VO₄, a potent protein-tyrosine phosphatase inhibitor, has revealed not only the different intracellular trafficking pathways of Src-family tyrosine kinase members but also novel tyrosine phosphorylation signals in the nucleus and on mitotic spindle fibers and lysosomes. Furthermore, despite that the first identified oncogene product v-Src is generally believed to induce transformation through continuous stimulation of proliferation signaling by its strong tyrosine kinase activity, v-Src-driven transformation was found to be caused not by continuous proliferation signaling but by v-Src tyrosine kinase activity-dependent stochastic genome alterations. Here, I summarize our findings regarding novel tyrosine phosphorylation signaling in a spatiotemporal sense and highlight the significance of the roles of tyrosine phosphorylation in transcriptional regulation inside the nucleus and chromosome dynamics.

Deletion of Jdp2 enhances Slc7a11 expression in Atoh-1 positive cerebellum granule cell progenitors in vivo

Background

The cerebellum is the sensitive region of the brain to developmental abnormalities related to the effects of oxidative stresses. Abnormal cerebellar lobe formation, found in Jun dimerization protein 2 (Jdp2)-knockout (KO) mice, is related to increased antioxidant formation and a reduction in apoptotic cell death in granule cell progenitors (GCPs). Here, we aim that Jdp2 plays a critical role of cerebellar development which is affected by the ROS regulation and redox control.

Objective

Jdp2-promoter-Cre transgenic mouse displayed a positive signal in the cerebellum, especially within granule cells. Jdp2-KO mice exhibited impaired development of the cerebellum compared with wild-type (WT) mice. The antioxidation controlled gene, such as cystine-glutamate transporter Slc7a11, might be critical to regulate the redox homeostasis and the development of the cerebellum.

Methods

We generated the Jdp2-promoter-Cre mice and Jdp2-KO mice to examine the levels of Slc7a11, ROS levels and the expressions of antioxidation related genes were examined in the mouse cerebellum using the immunohistochemistry.

Results

The cerebellum of Jdp2-KO mice displayed expression of the cystine-glutamate transporter Slc7a11, within the internal granule layer at postnatal day 6; in contrast, the WT cerebellum mainly displayed Sla7a11 expression in the external granule layer. Moreover, development of the cerebellar lobes in Jdp2-KO mice was altered compared with WT mice. Expression of Slc7a11, Nrf2, and p21^Cip1 was higher in the cerebellum of Jdp2-KO mice than in WT mice.

Conclusion

Jdp2 is a critical regulator of Slc7a11 transporter during the antioxidation response, which might control the growth, apoptosis, and differentiation of GCPs in the cerebellar lobes. These observations are consistent with our previous study in vitro.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02424-4.

Candidate plasticity gene 16 and jun dimerization protein 2 are involved in the suppression of insulin gene expression in rat pancreatic INS-1 β-cells

Chronic hyperglycemia causes pancreatic β-cell dysfunction, impaired insulin secretion and the suppression of insulin gene expression. This phenomenon is referred to as glucotoxicity, and is a critical component of the pathogenesis of type 2 diabetes. We previously reported that the expression of candidate plasticity gene 16 (CPG16) was higher in rat pancreatic INS-1 β-cells under glucotoxic conditions and CPG16 suppressed insulin promoter activity. However, the molecular mechanisms of the CPG16-mediated suppression of insulin gene expression are unclear. In this study, we found that CPG16 directly bound and phosphorylated jun dimerization protein 2 (JDP2), an AP-1 family transcription factor. CPG16 co-localized with JDP2 in the nucleus of INS-1 cells. JDP2 bound to the G1 element of the insulin promoter and up-regulated promoter activity. Finally, CPG16 suppressed the up-regulation of insulin promoter activity by JDP2 in a kinase activity-dependent manner. These results suggest that CPG16 suppresses insulin promoter activity by phosphorylating JDP2.

JDP2, a Novel Molecular Key in Heart Failure and Atrial Fibrillation?

Heart failure (HF) and atrial fibrillation (AF) are two major life-threatening diseases worldwide. Causes and mechanisms are incompletely understood, yet current therapies are unable to stop disease progression. In this review, we focus on the contribution of the transcriptional modulator, Jun dimerization protein 2 (JDP2), and on HF and AF development. In recent years, JDP2 has been identified as a potential prognostic marker for HF development after myocardial infarction. This close correlation to the disease development suggests that JDP2 may be involved in initiation and progression of HF as well as in cardiac dysfunction. Although no studies have been done in humans yet, studies on genetically modified mice impressively show involvement of JDP2 in HF and AF, making it an interesting therapeutic target.

The role of Nrf2 in autoimmunity and infectious disease: Therapeutic possibilities

Nrf2 is a cytoprotective transcription factor which is involved in ameliorating oxidative stress and toxic insults. Recently, an immunomodulatory role for Nrf2 has gained appreciation as it has been shown to protect cells and hosts alike in a variety of immune and inflammatory disorders. However, Nrf2 utilizes numerous distinct pathways to elicit its immunomodulatory effects. In this review, we summarize the literature discussing the roles of Nrf2 in autoimmunity and infectious diseases with a goal of understanding the potential to therapeutically target Nrf2.

Dimethyl sulfoxide stimulates the AhR-Jdp2 axis to control ROS accumulation in mouse embryonic fibroblasts

The aryl hydrocarbon receptor (AhR) is a ligand-binding protein that responds to environmental aromatic hydrocarbons and stimulates the transcription of downstream phase I enzyme–related genes by binding the cis element of dioxin-responsive elements (DREs)/xenobiotic-responsive elements. Dimethyl sulfoxide (DMSO) is a well-known organic solvent that is often used to dissolve phase I reagents in toxicology and oxidative stress research experiments. In the current study, we discovered that 0.1% DMSO significantly induced the activation of the AhR promoter via DREs and produced reactive oxygen species, which induced apoptosis in mouse embryonic fibroblasts (MEFs). Moreover, Jun dimerization protein 2 (Jdp2) was found to be required for activation of the AhR promoter in response to DMSO. Coimmunoprecipitation and chromatin immunoprecipitation studies demonstrated that the phase I–dependent transcription factors, AhR and the AhR nuclear translocator, and phase II–dependent transcription factors such as nuclear factor (erythroid-derived 2)–like 2 (Nrf2) integrated into DRE sites together with Jdp2 to form an activation complex to increase AhR promoter activity in response to DMSO in MEFs. Our findings provide evidence for the functional role of Jdp2 in controlling the AhR gene via Nrf2 and provide insights into how Jdp2 contributes to the regulation of ROS production and the cell spreading and apoptosis produced by the ligand DMSO in MEFs.

JDP2 is directly regulated by ATF4 and modulates TRAIL sensitivity by suppressing the ATF4-DR5 axis

Jun dimerization protein 2 (JDP2) is a bZip‐type transcription factor, which acts as a repressor or activator of several cellular processes, including cell differentiation and chromatin remodeling. Previously, we found that a stress‐responsive transcription factor, known as activating transcription factor 4 (ATF4), enhances JDP2 gene expression in human astrocytoma U373MG and cervical cancer HeLa cells; however, the role of JDP2 in the ATF4‐mediated stress response remained unclear. Here, we reported that siRNA‐mediated JDP2 knockdown enhances the expression of several ATF4 target genes, including ASNS, and death receptors 4 and 5 (DR4 and DR5) in HeLa cells. In addition, the results of a transient reporter assay indicate that JDP2 overexpression represses ER stress‐mediated DR5 promoter activation suggesting that JDP2 negatively regulates ATF4‐mediated gene expression. Curiously, knockdown of JDP2 increases the sensitivity of cells to TNF‐related apoptosis‐inducing ligand (TRAIL), which induces apoptosis in cancer cells through DR4 and DR5. These results indicate that JDP2 functions as a negative feedback regulator of the ATF4 pathway and contributes to TRAIL resistance in cancer cells.

Prevention of tumor risk associated with the reprogramming of human pluripotent stem cells

Human pluripotent embryonic stem cells have two special features: self-renewal and pluripotency. It is important to understand the properties of pluripotent stem cells and reprogrammed stem cells. One of the major problems is the risk of reprogrammed stem cells developing into tumors. To understand the process of differentiation through which stem cells develop into cancer cells, investigators have attempted to identify the key factors that generate tumors in humans. The most effective method for the prevention of tumorigenesis is the exclusion of cancer cells during cell reprogramming. The risk of cancer formation is dependent on mutations of oncogenes and tumor suppressor genes during the conversion of stem cells to cancer cells and on the environmental effects of pluripotent stem cells. Dissecting the processes of epigenetic regulation and chromatin regulation may be helpful for achieving correct cell reprogramming without inducing tumor formation and for developing new drugs for cancer treatment. This review focuses on the risk of tumor formation by human pluripotent stem cells, and on the possible treatment options if it occurs. Potential new techniques that target epigenetic processes and chromatin regulation provide opportunities for human cancer modeling and clinical applications of regenerative medicine.

Jdp2-deficient granule cell progenitors in the cerebellum are resistant to ROS-mediated apoptosis through xCT/Slc7a11 activation

The Jun dimerization protein 2 (Jdp2) is expressed predominantly in granule cell progenitors (GCPs) in the cerebellum, as was shown in Jdp2-promoter-Cre transgenic mice. Cerebellum of Jdp2-knockout (KO) mice contains lower number of Atoh-1 positive GCPs than WT. Primary cultures of GCPs from Jdp2-KO mice at postnatal day 5 were more resistant to apoptosis than GCPs from wild-type mice. In Jdp2-KO GCPs, the levels of both the glutamate‒cystine exchanger Sc7a11 and glutathione were increased; by contrast, the activity of reactive oxygen species (ROS) was decreased; these changes confer resistance to ROS-mediated apoptosis. In the absence of Jdp2, a complex of the cyclin-dependent kinase inhibitor 1 (p21^Cip1) and Nrf2 bound to antioxidant response elements of the Slc7a11 promoter and provide redox control to block ROS-mediated apoptosis. These findings suggest that an interplay between Jdp2, Nrf2, and p21^Cip1 regulates the GCP apoptosis, which is one of critical events for normal development of the cerebellum.

Effects of Ethyl Pyruvate on Bile Duct Ligation-Induced Liver Fibrosis by Regulating Nrf2 Pathway and Proinflammatory Cytokines in Rats

Aim

The aim of this paper is to investigate the effects of ethyl pyruvate (EP) on experimental liver fibrosis induced by bile duct ligation (BDL) and explore the underlying molecular mechanisms.

Material and Method

Rats were randomly divided into three groups: the sham group, the BDL group, and the BDL+EP group. Liver fibrosis was induced by common bile duct ligation and was evaluated by serum biochemical parameter levels, Masson's trichrome staining, α-SMA expression, and collagen I deposition. The levels of Nrf2 signaling pathway-related antioxidant genes (Nrf2, SOD2, NQO1, and GSH-Px) in liver tissues were also measured. Meanwhile, the mRNA expression levels of HMGB1, IL-1β, TNF-α, and HSP27 were analyzed. In BDL-induced liver fibrosis rats, the successfully established model was confirmed by the significant increase of serum ALT and AST levels, the high liver fibrosis score, α-SMA expression, and collagen deposition.

Results

Compared with the BDL group, EP administration could diminish fibrosis level and substantially increase the expression of Nrf2 signaling pathway-related antioxidant genes. Furthermore, EP significantly suppressed the mRNA expression levels of HMGB1, IL-1β, TNF-α, and HSP27.

Conclusions

The results suggested that EP administration could effectively inhibit the liver fibrosis induced by BDL in rat, which may be associated with the enhanced activity of Nrf2 to mediate antioxidant enzyme system and downregulate the inflammatory genes.

Genotoxic stress-triggered β-catenin/JDP2/PRMT5 complex facilitates reestablishing glutathione homeostasis

The mechanisms underlying how cells subjected to genotoxic stress reestablish reduction-oxidation (redox) homeostasis to scavenge genotoxic stress-induced reactive oxygen species (ROS), which maintains the physiological function of cellular processes and cell survival, remain unclear. Herein, we report that, via a TCF-independent mechanism, genotoxic stress induces the enrichment of β-catenin in chromatin, where it forms a complex with ATM phosphorylated-JDP2 and PRMT5. This elicits histone H3R2me1/H3R2me2s-induced transcriptional activation by the recruitment of the WDR5/MLL methyltransferase complexes and concomitant H3K4 methylation at the promoters of multiple genes in GSH-metabolic cascade. Treatment with OICR-9429, a small-molecule antagonist of the WDR5-MLL interaction, inhibits the β-catenin/JDP2/PRMT5 complex-reestablished GSH metabolism, leading to a lethal increase in the already-elevated levels of ROS in the genotoxic-agent treated cancer cells. Therefore, our results unveil a plausible role for β-catenin in reestablishing redox homeostasis upon genotoxic stress and shed light on the mechanisms of inducible chemotherapy resistance in cancer.

It is known that genotoxic stress induces high levels of ROS and deplete cellular glutathione stores. Here, Cao et al. uncover a β-catenin-dependent TCF/LEF-independent mechanism that promotes histone-mediated transcriptional activation of glutathione synthesis.

Pharmacological Applications of Nrf2 Inhibitors as Potential Antineoplastic Drugs

Oxidative stress (OS) is associated with many diseases ranging from cancer to neurodegenerative disorders. Nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) is one of the most effective cytoprotective controller against OS. Modulation of Nrf2 pathway constitutes a remarkable strategy in the antineoplastic treatments. A big number of Nrf2-antioxidant response element activators have been screened for use as chemo-preventive drugs in OS associated diseases like cancer even though activation of Nrf2 happens in a variety of cancers. Research proved that hyperactivation of the Nrf2 pathway produces a situation that helps the survival of normal as well as malignant cells, protecting them against OS, anticancer drugs, and radiotherapy. In this review, the modulation of the Nrf2 pathway, anticancer activity and challenges associated with the development of an Nrf2-based anti-cancer treatment approaches are discussed.

Gene expression analysis in peripheral blood cells of patients with hereditary leiomyomatosis and renal cell cancer syndrome (HLRCC): identification of NRF2 pathway activation

Hereditary leiomyomatosis and renal cell cancer syndrome (HLRCC) is a very rare disease that is inherited in an autosomal dominant manner. Affected patients may develop from cutaneous and uterine leiomyomas to type 2 papillary renal cell carcinoma (Schmidt and Linehan, Int J Nephrol Renovasc Dis 7:253-260, 2014). HLRCC is caused by germline mutations in the FH gene, which produces the fumarate hydratase protein that participates in the tricarboxylic acid cycle during the conversion of fumarate to malate. In FH-deficient cells, high concentrations of fumarate lead to a series of intricate events, which seem to be responsible for the malignant transformation (Yang et al., J Clin Invest 123(9):3652-3658, 2013) (Bardella et al., J Pathol 225(1):4-11, 2011). Among these events, one that is gaining attention is the pathological activation of the nuclear factor erythroid 2-related factor 2 (NRF2) pathway, which has been found in several types of cancer and is implicated in the expression of genes associated with antioxidant responses (Linehan and Rouault, Clin Cancer Res 19(13):3345-3352, 2013). In this article, we present the results of a gene expression analysis performed on peripheral blood cells from patients with HLRCC syndrome, where upregulation of numerous NRF2 targets and the differential expression of two key genes, Jun dimerization protein 2 (JDP2) and Phosphoglycerate mutase family member 5 (PGAM5), which are involved in the control of this pathway, was observed.

Potential application of cell reprogramming techniques for cancer research

The ability to control the transition from an undifferentiated stem cell to a specific cell fate is one of the key techniques that are required for the application of interventional technologies to regenerative medicine and the treatment of tumors and metastases and of neurodegenerative diseases. Reprogramming technologies, which include somatic cell nuclear transfer, induced pluripotent stem cells, and the direct reprogramming of specific cell lineages, have the potential to alter cell plasticity in translational medicine for cancer treatment. The characterization of cancer stem cells (CSCs), the identification of oncogene and tumor suppressor genes for CSCs, and the epigenetic study of CSCs and their microenvironments are important topics. This review summarizes the application of cell reprogramming technologies to cancer modeling and treatment and discusses possible obstacles, such as genetic and epigenetic alterations in cancer cells, as well as the strategies that can be used to overcome these obstacles to cancer research.

Crosstalk of toll-like receptors signaling and Nrf2 pathway for regulation of inflammation

Inflammation as a second line of defense of innate immunity plays a crucial role in eliminating invading pathogens (bacteria, viruses, fungi as well as other parasites). The inflammatory response may also activate adaptive immune system involving lymphocytes to mount either antibody dependent or cell-mediated immune responses to clear pathogenic insult. However, if continued, the inflammatory processes may become uncontrolled culminating in cellular injury and tissue destruction, thereby manifesting itself in chronic form. The chronic inflammation has been associated with numerous human pathological conditions like allergies and autoimmune diseases, atherosclerosis, arthritis, Alzheimer's disease, cancer, obesity, type 2 diabetes, schizophrenia, neuro-degenerative diseases and numerous others. The dysregulated inflammatory process is associated with overproduction of free radicals leading to oxidative stress and activation of different cell signaling pathways. The regulation of inflammation by TLR signaling as well as Nrf2 pathways separately is widely documented. Since both these major signaling pathways modulate inflammation, they may crosstalk to bring about coordinated inflammatory responses. The linkage between TLR signaling and Nrf2-Keap1 pathway may serve as a bridge between immune regulation and oxidative stress responses through regulation of inflammation. Also, inflammation is reportedly responsible for the plethora of diseased conditions; a study of its regulation by targeting the TLR-Nrf2 cross-talks may also be beneficial for the development of therapeutic therapies or prophylactic treatments. Hence, present review focuses on the crosstalk between TLR signaling and Nrf2 pathway with respect to their role in modulation of inflammation in normal as well as pathologic conditions.

Canonical and non-canonical mechanisms of Nrf2 activation

Nuclear Factor Erythroid 2-related factor 2 (Nrf2) is a transcription factor that regulates the expression of genes involved in the metabolism, immune response, cellular proliferation, and other processes; however, the attention has been focused on the study of its ability to induce the expression of proteins involved in the antioxidant defense. Nrf2 is mainly regulated by Kelch-like ECH-associated protein 1 (Keap1), an adapter substrate of Cullin 3 (Cul3) ubiquitin E3 ligase complex. Keap1 represses Nrf2 activity in the cytoplasm by its sequestering, ubiquitination and proteosomal degradation. Nrf2 activation, through the canonical mechanism, is carried out by electrophilic compounds and oxidative stress where some cysteine residues in Keap1 are oxidized, resulting in a decrease in Nrf2 ubiquitination and an increase in its nuclear translocation and activation. In the nucleus, Nrf2 induces a variety of genes involved in the antioxidant defense. Recently a new mechanism of Nrf2 activation has been described, called the non-canonical pathway, where proteins such as p62, p21, dipeptidyl peptidase III (DPP3), wilms tumor gene on X chromosome (WTX) and others are able to disrupt the Nrf2-Keap1 complex, by direct interaction with Keap1 decreasing Nrf2 ubiquitination and increasing its nuclear translocation and activation. In this review, the regulatory mechanisms involved in both canonical and non-canonical Nrf2 activation are discussed.

Inducers of Senescence, Toxic Compounds, and Senolytics: The Multiple Faces of Nrf2-Activating Phytochemicals in Cancer Adjuvant Therapy

The reactivation of senescence in cancer and the subsequent clearance of senescent cells are suggested as therapeutic intervention in the eradication of cancer. Several natural compounds that activate Nrf2 (nuclear factor erythroid-derived 2-related factor 2) pathway, which is involved in complex cytoprotective responses, have been paradoxically shown to induce cell death or senescence in cancer. Promoting the cytoprotective Nrf2 pathway may be desirable for chemoprevention, but it might be detrimental in later stages and advanced cancers. However, senolytic activity shown by some Nrf2-activating compounds could be used to target senescent cancer cells (particularly in aged immune-depressed organisms) that escape immunosurveillance. We herein describe in vitro and in vivo effects of fifteen Nrf2-interacting natural compounds (tocotrienols, curcumin, epigallocatechin gallate, quercetin, genistein, resveratrol, silybin, phenethyl isothiocyanate, sulforaphane, triptolide, allicin, berberine, piperlongumine, fisetin, and phloretin) on cellular senescence and discuss their use in adjuvant cancer therapy. In light of available literature, it can be concluded that the meaning and the potential of adjuvant therapy with natural compounds in humans remain unclear, also taking into account the existence of few clinical trials mostly characterized by uncertain results. Further studies are needed to investigate the therapeutic potential of those compounds that display senolytic activity.

Discovery of cell-type specific DNA motif grammar in cis-regulatory elements using random Forest

Background

It has been observed that many transcription factors (TFs) can bind to different genomic loci depending on the cell type in which a TF is expressed in, even though the individual TF usually binds to the same core motif in different cell types. How a TF can bind to the genome in such a highly cell-type specific manner, is a critical research question. One hypothesis is that a TF requires co-binding of different TFs in different cell types. If this is the case, it may be possible to observe different combinations of TF motifs – a motif grammar – located at the TF binding sites in different cell types. In this study, we develop a bioinformatics method to systematically identify DNA motifs in TF binding sites across multiple cell types based on published ChIP-seq data, and address two questions: (1) can we build a machine learning classifier to predict cell-type specificity based on motif combinations alone, and (2) can we extract meaningful cell-type specific motif grammars from this classifier model.

Results

We present a Random Forest (RF) based approach to build a multi-class classifier to predict the cell-type specificity of a TF binding site given its motif content. We applied this RF classifier to two published ChIP-seq datasets of TF (TCF7L2 and MAX) across multiple cell types. Using cross-validation, we show that motif combinations alone are indeed predictive of cell types. Furthermore, we present a rule mining approach to extract the most discriminatory rules in the RF classifier, thus allowing us to discover the underlying cell-type specific motif grammar.

Conclusions

Our bioinformatics analysis supports the hypothesis that combinatorial TF motif patterns are cell-type specific.

Electronic supplementary material

The online version of this article (10.1186/s12864-017-4340-z) contains supplementary material, which is available to authorized users.

Oncogenic function of the homeobox A13-long noncoding RNA HOTTIP-insulin growth factor-binding protein 3 axis in human gastric cancer

To study the mechanisms of gastric tumorigenesis, we have established CSN cell line from human normal gastric mucosa, and CS12, a tumorigenic and invasive gastric cancer cell line from CSN passages. Many stem cell markers were expressed in both CSN and CS12 cells, but LGR5 and NANOG were expressed only in CS12 cells. Increased expression of homeobox A13 (HoxA13) and its downstream cascades was significant for the tumorigenic activity of CS12 cells, and was associated with recruitment of E2F-1 to HoxA13 promoter accompanied with increased trimethylation of histone H3 lysine 4 (H3K4me3) at the hypomethylated E2F motifs. Knockdown of HoxA13 caused the downregulation of long non-coding RNA HOTTIP and insulin growth factor-binding protein 3 (IGFBP-3) genes, indicating that both were targets of HoxA13. Concurrent regulation of HoxA13-HOTTIP was mediated by the mixed lineage leukemia-WD repeat domain 5 complex, which caused the trimethylation of H3K4 and then stimulated cell proliferation. HoxA13 transactivated the IGFBP-3 promoter through the HOX-binding site. Activation of IGFBP-3 stimulated the oncogenic potential and invasion activity. Increased expression of HoxA13 (63.2%) and IGFBP-3 (28.6%) was detected in human gastric cancer tissues and was found in the gastric cancer data of The Cancer Genome Atlas. Taken together, the HoxA13–HOTTIP–IGFBP-3 cascade is critical for the carcinogenic characteristics of CS12 cells.

Reprogramming Antagonizes the Oncogenicity of HOXA13-Long Noncoding RNA HOTTIP Axis in Gastric Cancer Cells

Reprogramming of cancer cells into induced pluripotent stem cells (iPSCs) is a compelling idea for inhibiting oncogenesis, especially through modulation of homeobox proteins in this reprogramming process. We examined the role of various long noncoding RNAs (lncRNAs)-homeobox protein HOXA13 axis on the switching of the oncogenic function of bone morphogenetic protein 7 (BMP7), which is significantly lost in the gastric cancer cell derived iPS-like cells (iPSLCs). BMP7 promoter activation occurred through the corecruitment of HOXA13, mixed-lineage leukemia 1 lysine N-methyltransferase, WD repeat-containing protein 5, and lncRNA HoxA transcript at the distal tip (HOTTIP) to commit the epigenetic changes to the trimethylation of lysine 4 on histone H3 in cancer cells. By contrast, HOXA13 inhibited BMP7 expression in iPSLCs via the corecruitment of HOXA13, enhancer of zeste homolog 2, Jumonji and AT rich interactive domain 2, and lncRNA HoxA transcript antisense RNA (HOTAIR) to various cis-element of the BMP7 promoter. Knockdown experiments demonstrated that HOTTIP contributed positively, but HOTAIR regulated negatively to HOXA13-mediated BMP7 expression in cancer cells and iPSLCs, respectively. These findings indicate that the recruitment of HOXA13-HOTTIP and HOXA13-HOTAIR to different sites in the BMP7 promoter is crucial for the oncogenic fate of human gastric cells. Reprogramming with octamer-binding protein 4 and Jun dimerization protein 2 can inhibit tumorigenesis by switching off BMP7. Stem Cells 2017;35:2115-2128.

Individual expression features of GPX2, NQO1 and SQSTM1 transcript variants induced by hydrogen peroxide treatment in HeLa cells

Pathway activity assessment-based approaches are becoming highly influential in various fields of biology and medicine. However, these approaches mostly rely on analysis of mRNA expression, and total mRNA from a given locus is measured in the majority of cases. Notably, a significant portion of protein-coding genes produces more than one transcript. This biological fact is responsible for significant noise when changes in total mRNA transcription of a single gene are analyzed. The NFE2L2/AP-1 pathway is an attractive target for biomedical applications. To date, there is a lack of data regarding the agreement in expression of even classical target genes of this pathway. In the present paper we analyzed whether transcript variants of GPX2, NQO1 and SQSTM1 were characterized by individual features of expression when HeLa cells were exposed to pro-oxidative stimulation with hydrogen peroxide. We found that all the transcripts (10 in total) appeared to be significantly individually regulated under the conditions tested. We conclude that individual transcripts, rather than total mRNA, are best markers of pathway activation. We also discuss here some biological roles of individual transcript regulation.

A pre-neoplastic epigenetic field defect in HCV-infected liver at transcription factor binding sites and polycomb targets

The predisposition of patients with Hepatitis C virus (HCV) infection to hepatocellular carcinoma (HCC) involves components of viral infection, inflammation and time. The development of multifocal, genetically distinct tumours is suggestive of a field defect affecting the entire liver. The molecular susceptibility mediating such a field defect is not understood. One potential mediator of long-term cellular reprogramming is heritable (epigenetic) regulation of transcription, exemplified by DNA methylation. We studied epigenetic and transcriptional changes in HCV-infected livers in comparison with control, uninfected livers and HCC, allowing us to identify pre-neoplastic epigenetic and transcriptional events. We find the HCV-infected liver to have a pattern of acquisition of DNA methylation targeted to candidate enhancers active in liver cells, enriched for the binding sites of the FOXA1, FOXA2 and HNF4A transcription factors. These enhancers can be subdivided into those proximal to genes implicated in liver cancer or to genes involved in stem cell development, the latter distinguished by increased CG dinucleotide density and polycomb-mediated repression, manifested by the additional acquisition of histone H3 lysine 27 trimethylation (H3K27me3). Transcriptional studies on our samples showed that the increased DNA methylation at enhancers was associated with decreased local gene expression, results validated in independent samples from The Cancer Genome Atlas. Pharmacological depletion of H3K27me3 using the EZH2 inhibitor GSK343 in HepG2 cells suppressed cell growth and also revealed that local acquired DNA methylation was not dependent upon the presence of polycomb-mediated repression. The results support a model of HCV infection influencing the binding of transcription factors to cognate sites in the genome, with consequent local acquisition of DNA methylation, and the added repressive influence of polycomb at a subset of CG-dense cis-regulatory sequences. These epigenetic events occur before neoplastic transformation, resulting in what may be a pharmacologically reversible epigenetic field defect in HCV-infected liver.

Positive Feedback Loop of OCT4 and c-JUN Expedites Cancer Stemness in Liver Cancer

The network of stemness genes and oncogenes in human patient-specific reprogrammed cancer stem cells (CSCs) remains elusive, especially in liver cancer. HepG2-derived induced pluripotent stem cell-like cells (HepG2-iPS-like cells) were generated by introducing Yamanaka factors and the knockdown vector shTP53. They exhibited features of stemness and a higher tumorigenesis after xenograft transplantation compared with HepG2 cells. The cancerous mass of severe combined immunodeficiency (SCID) mice derived from one colony was dissected and cultured to establish reprogrammed HepG2-derived CSC-like cells (designated rG2-DC-1C). A single colony exhibited 42% occurrence of tumors with higher proliferation capacities. rG2-DC-1C showed continuous expression of the OCT4 stemness gene and of representative tumor markers, potentiated chemoresistance characteristics, and invasion activities. The sphere-colony formation ability and the invasion activity of rG2-DC-1C were also higher than those of HepG2 cells. Moreover, the expression of the OCT4 gene and the c-JUN oncogene, but not of c-MYC, was significantly elevated in rG2-DC-1C, whereas no c-JUN expression was observed in HepG2 cells. The positive-feedback regulation via OCT4-mediated transactivation of the c-JUN promoter and the c-JUN-mediated transactivation of the OCT4 promoter were crucial for promoting cancer development and maintaining cancer stemness in rG2-DC-1C. Increased expression of OCT4 and c-JUN was detected in the early stage of human liver cancer. Therefore, the positive feedback regulation of OCT4 and c-JUN, resulting in the continuous expression of oncogenes such as c-JUN, seems to play a critical role in the determination of the cell fate decision from iPS cells to CSCs in liver cancer. Stem Cells 2016;34:2613-2624.

Multiple functions of the histone chaperone Jun dimerization protein 2

The Jun dimerization protein 2 (JDP2) is part of the family of stress-responsible transcription factors such as the activation protein-1, and binds the 12-O-tetradecanoylphorbol-13-acetateresponse element and the cAMP response element. It also plays a role as a histone chaperone and participates in diverse processes, such as cell-cycle arrest, cell differentiation, apoptosis, senescence, and metastatic spread, and functions as an oncogene and anti-oncogene, and as a cellular reprogramming factor. However, the molecular mechanisms underlying these multiple functions of JDP2 have not been clarified. This review summarizes the structure and function of JDP2, highlighting the specific role of JDP2 in cellular-stress regulation and prevention.

The E3 ligase Itch knockout mice show hyperproliferation and wound healing alteration

The HECT-type E3 ubiquitin ligase Itch is absent in the non-agouti-lethal 18H or Itchy mice, which develop a severe immunological disease. Several of the known Itch substrates are relevant for epidermal development and homeostasis, such as p63, Notch, c-Jun and JunB. By analysing Itchy mice before the onset of immunological alterations, we investigated the contribution of Itch in skin development and wound healing. Itchy newborn mice manifested hyperplastic epidermis, which is not present in adulthood. Itch(-/-) cultured keratinocytes showed overexpression of proliferating markers and increased capability to proliferate, migrate and to repair a scratch injury in vitro. These data correlated with improved in vivo wound healing in Itchy mice, at late time points of the repair process when Itch is physiologically upregulated. Despite healing acceleration, epidermal remodelling was delayed in the scars of Itch(-/-) mice, as indicated by enhanced epidermal thickening, keratinocyte proliferation and keratin 6 expression, and retarded keratin 14 polarization to the basal layer. Itch(-/-) keratinocyte prolonged activation was not associated with increased immune cell persistence in the scars. Our in vitro and in vivo results indicate that Itch plays a role in epidermal homeostasis and remodelling and this feature does not seem to depend on immunological alterations.

Emerging roles of hypoxia-inducible factors and reactive oxygen species in cancer and pluripotent stem cells

Eukaryotic organisms require oxygen homeostasis to maintain proper cellular function for survival. During conditions of low oxygen tension (hypoxia), cells activate the transcription of genes that induce an adaptive response, which supplies oxygen to tissues. Hypoxia and hypoxia-inducible factors (HIFs) may contribute to the maintenance of putative cancer stem cells, which can continue self-renewal indefinitely and express stemness genes in hypoxic stress environments (stem cell niches). Reactive oxygen species (ROS) have long been recognized as toxic by-products of aerobic metabolism that are harmful to living cells, leading to DNA damage, senescence, or cell death. HIFs may promote a cancer stem cell state, whereas the loss of HIFs induces the production of cellular ROS and activation of proteins p53 and p16(Ink4a), which lead to tumor cell death and senescence. ROS seem to inhibit HIF regulation in cancer cells. By contrast, controversial data have suggested that hypoxia increases the generation of ROS, which prevents hydroxylation of HIF proteins by inducing their transcription as negative feedback. Moreover, hypoxic conditions enhance the generation of induced pluripotent stem cells (iPSCs). During reprogramming of somatic cells into a PSC state, cells attain a metabolic state typically observed in embryonic stem cells (ESCs). ESCs and iPSCs share similar bioenergetic metabolisms, including decreased mitochondrial number and activity, and induced anaerobic glycolysis. This review discusses the current knowledge regarding the emerging roles of ROS homeostasis in cellular reprogramming and the implications of hypoxic regulation in cancer development.

Inhibitor of differentiation proteins protect against oxidative stress by regulating the antioxidant-mitochondrial response in mouse beta cells

AIMS/HYPOTHESIS

Oxidative stress is implicated in beta cell glucotoxicity in type 2 diabetes. Inhibitor of differentiation (ID) proteins are transcriptional regulators induced by hyperglycaemia in islets, but the mechanisms involved and their role in beta cells are not clear. Here we investigated whether or not oxidative stress regulates ID levels in beta cells and the role of ID proteins in beta cells during oxidative stress.

METHODS

MIN6 cells were cultured in H2O2 or ribose to induce oxidative stress. ID1, ID3 and small MAF proteins (MAFF, MAFG and MAFK) were inhibited using small interfering RNA. Isolated islets from Id1(-/-), Id3(-/-) and diabetic db/db mice were used.

RESULTS

ID1-4 expression was upregulated in vivo in the islets of diabetic db/db mice and stimulated in vitro by ribose and H2O2. Id1/3 inhibition reduced the expression of multiple antioxidant genes and potentiated oxidative stress-induced apoptosis. This finding was associated with increased levels of intracellular reactive oxygen species, altered mitochondrial morphology and reduced expression of Tfam, which encodes a mitochondrial transcription factor, and respiratory chain components. Id1/3 inhibition also reduced the expression of small MAF transcription factors (MafF, MafG and MafK), interacting partners of nuclear factor, erythroid 2-like 2 (NFE2L2), master regulator of the antioxidant response. Inhibition of small MAFs reduced the expression of antioxidant genes and potentiated oxidative stress-induced apoptosis, thus recapitulating the effects of Id1/3 inhibition.

CONCLUSIONS/INTERPRETATION

Our study identifies IDs as a novel family of oxidative stress-responsive proteins in beta cells. IDs are crucial regulators of the adaptive antioxidant-mitochondrial response that promotes beta cell survival during oxidative stress through a novel link to the NFE2L2-small MAF pathway.

Smyd1 facilitates heart development by antagonizing oxidative and ER stress responses

Smyd1/Bop is an evolutionary conserved histone methyltransferase previously shown by conventional knockout to be critical for embryonic heart development. To further explore the mechanism(s) in a cell autonomous context, we conditionally ablated Smyd1 in the first and second heart fields of mice using a knock-in (KI) Nkx2.5-cre driver. Robust deletion of floxed-Smyd1 in cardiomyocytes and the outflow tract (OFT) resulted in embryonic lethality at E9.5, truncation of the OFT and right ventricle, and additional defects consistent with impaired expansion and proliferation of the second heart field (SHF). Using a transgenic (Tg) Nkx2.5-cre driver previously shown to not delete in the SHF and OFT, early embryonic lethality was bypassed and both ventricular chambers were formed; however, reduced cardiomyocyte proliferation and other heart defects resulted in later embryonic death at E11.5-12.5. Proliferative impairment prior to both early and mid-gestational lethality was accompanied by dysregulation of transcripts critical for endoplasmic reticulum (ER) stress. Mid-gestational death was also associated with impairment of oxidative stress defense—a phenotype highly similar to the previously characterized knockout of the Smyd1-interacting transcription factor, skNAC. We describe a potential feedback mechanism in which the stress response factor Tribbles3/TRB3, when directly methylated by Smyd1, acts as a co-repressor of Smyd1-mediated transcription. Our findings suggest that Smyd1 is required for maintaining cardiomyocyte proliferation at minimally two different embryonic heart developmental stages, and its loss leads to linked stress responses that signal ensuing lethality.

Gene expression profiling reveals potential prognostic biomarkers associated with the progression of heart failure

Background

Heart failure (HF) is the most common cause of morbidity and mortality in developed countries. Here, we identify biologically relevant transcripts that are significantly altered in the early phase of myocardial infarction and are associated with the development of post-myocardial infarction HF.

Methods

We collected peripheral blood samples from patients with ST-segment elevation myocardial infarction (STEMI): n = 111 and n = 41 patients from the study and validation groups, respectively. Control groups comprised patients with a stable coronary artery disease and without a history of myocardial infarction. Based on plasma NT-proBNP level and left ventricular ejection fraction parameters the STEMI patients were divided into HF and non-HF groups. Microarrays were used to analyze mRNA levels in peripheral blood mononuclear cells (PBMCs) isolated from the study group at four time points and control group. Microarray results were validated by RT-qPCR using whole blood RNA from the validation group.

Results

Samples from the first three time points (admission, discharge, and 1 month after AMI) were compared with the samples from the same patients collected 6 months after AMI (stable phase) and with the control group. The greatest differences in transcriptional profiles were observed on admission and they gradually stabilized during the follow-up. We have also identified a set of genes the expression of which on the first day of STEMI differed significantly between patients who developed HF after 6 months of observation and those who did not. RNASE1, FMN1, and JDP2 were selected for further analysis and their early up-regulation was confirmed in HF patients from both the study and validation groups. Significant correlations were found between expression levels of these biomarkers and clinical parameters. The receiver operating characteristic (ROC) curves indicated a good prognostic value of the genes chosen.

Conclusions

This study demonstrates an altered gene expression profile in PBMCs during acute myocardial infarction and through the follow-up. The identified gene expression changes at the early phase of STEMI that differentiated the patients who developed HF from those who did not could serve as a convenient tool contributing to the prognosis of heart failure.

Electronic supplementary material

The online version of this article (doi:10.1186/s13073-015-0149-z) contains supplementary material, which is available to authorized users.

Nrf2 sensitizes prostate cancer cells to radiation via decreasing basal ROS levels

Androgen deprivation therapy (ADT) was reported to lower basal ROS level in prostate cancer (PCa) and to sensitize PCa to radiation. We aimed to seek for the underlying molecular mechanism and to develop novel additive treatments to ADT in this regard. We simulated human androgen milieu in vitro and tested the ROS level in PCa cells undergoing ADT. We also tested the Nrf2 level in PCa cells with or without ADT. Genetic and pharmaceutical upregulation of Nrf2 was applied in vitro and in vivo in transgenic adenocarcinoma of the mouse prostate (TRAMP) mice with or without castration to investigate whether Nrf2 overexpression supplemented the effect of ADT in PCa. We first discovered that androgen deprivation increased basal ROS level in PCa cells with AR expression. We then found that genetic Nrf2 upregulation lowered basal ROS similar to ADT. Also, SFN sensitized PCa cell to radiation via upregulation of Nrf2. We then found that Nrf2 level in control TRAMP groups was lower than castration or SFN groups. The SFN treated TRAMP mice showed similar level of Nrf2 to castration. Genetic and pharmaceutical upregulation of Nrf2 lowered the ROS in PCa cells and sensitized PCa cells to radiation similar to ADT, implicating possible administration of SFN in place of ADT for PCa patients requiring radiotherapy.

Cdk1-mediated phosphorylation of human ATF7 at Thr-51 and Thr-53 promotes cell-cycle progression into M phase

Activating transcription factor 2 (ATF2) and its homolog ATF7 are phosphorylated at Thr-69/Thr-71 and at Thr-51/Thr-53, respectively, by stress-activated MAPKs regulating their transcriptional functions in G1 and S phases. However, little is known about the role of ATF2 and ATF7 in G2/M phase. Here, we show that Cdk1-cyclin B1 phosphorylates ATF2 at Thr-69/Thr-71 and ATF7 at Thr-51/Thr-53 from early prophase to anaphase in the absence of any stress stimulation. Knockdown of ATF2 or ATF7 decreases the rate of cell proliferation and the number of cells in M-phase. In particular, the knockdown of ATF7 severely inhibits cell proliferation and G2/M progression. The inducible expression of a mitotically nonphosphorylatable version of ATF7 inhibits G2/M progression despite the presence of endogenous ATF7. We also show that mitotic phosphorylation of ATF7 promotes the activation of Aurora kinases, which are key enzymes for early mitotic events. These results suggest that the Cdk1-mediated phosphorylation of ATF7 facilitates G2/M progression, at least in part, by enabling Aurora signaling.

Cytoprotection "gone astray": Nrf2 and its role in cancer

Nrf2 has gained great attention with respect to its pivotal role in cell and tissue protection. Primarily defending cells against metabolic, xenobiotic and oxidative stress, Nrf2 is essential for maintaining tissue integrity. Owing to these functions, Nrf2 is regarded as a promising drug target in the chemoprevention of diseases, including cancer. However, much evidence has accumulated that the beneficial role of Nrf2 in cancer prevention essentially depends on the tight control of its activity. In fact, the deregulation of Nrf2 is a critical determinant in oncogenesis and found in many types of cancer. Therefore, amplified Nrf2 activity has profound effects on the phenotype of tumor cells, including radio/chemoresistance, apoptosis protection, invasiveness, antisenescence, autophagy deficiency, and angiogenicity. The deregulation of Nrf2 can result from various epigenetic and genetic alterations directly affecting Nrf2 control or from the complex interplay of Nrf2 with numerous oncogenic signaling pathways. Additionally, alterations of the cellular environment, eg, during inflammation, contribute to Nrf2 deregulation and its persistent activation. Therefore, the status of Nrf2 as anti- or protumorigenic is defined by many different modalities. A better understanding of these modalities is essential for the safe use of Nrf2 as an activation target for chemoprevention on the one hand and as an inhibition target in cancer therapy on the other. The present review mainly addresses the conditions that promote the oncogenic function of Nrf2 and the resulting consequences providing the rationale for using Nrf2 as a target structure in cancer therapy.

Cloning and characterization of the mouse JDP2 gene promoter reveal negative regulation by p53

Jun dimerization protein 2 (JDP2) is a repressor of transcription factor AP-1. To investigate the transcriptional regulation of the JDP2 gene, we cloned the 5'-flanking region of the mouse JDP2 gene. Primer extension analysis revealed a new transcription start site (+1). Promoter analysis showed that the region from nt -343 to nt +177 contains basal transcriptional activity. Interestingly, the tumor suppressor p53 significantly repressed the transcriptional activity of the JDP2 promoter. Given that JDP2 inhibits expression of p53, our results suggest a negative feedback loop between JDP2 and p53, and a direct link between JDP2 and a key oncogenic pathway.

Nuclear factor erythroid 2-related factor 2 rescues the oxidative stress induced by di-N-butylphthalate in testicular Leydig cells

Aim:

This study aimed to determine whether nuclear factor erythroid 2-related factor 2 antagonized the oxidative stress induced by di- N-butylphthalate (DBP) in testicular Leydig cells.

Methods:

Mouse TM3 testicular Leydig cells were treated with Nrf2 knockdown (KD) or overexpression in the presence and absence of DBP. Oxidative profiles were examined. Nrf2 target antioxidant genes were studied, and the effects of Nrf2 inducer sulphoraphane (SFN) were tested.

Results:

DBP induced intracellular oxidative stress to a similar extent with Nrf2 KD. Expression and protein levels of Nrf2 were increased together with its target genes, namely heme oxygenase 1, nicotinamide adenine dinucleotide phosphate quinone oxidoreductase 1 and peroxiredoxin 6, following DBP stimulation. Use of SFN not only restored the intracellular oxidative toxicity but also cell proliferation and testosterone secretion in response to DBP.

Conclusion:

Increased Nrf2 activity, for example, by SFN can effectively antagonize the oxidative stress in testicular Leydig cells caused by DBP.

Sall1 maintains nephron progenitors and nascent nephrons by acting as both an activator and a repressor

The balanced self-renewal and differentiation of nephron progenitors are critical for kidney development and controlled, in part, by the transcription factor Six2, which antagonizes canonical Wnt signaling-mediated differentiation. A nuclear factor, Sall1, is expressed in Six2-positive progenitors as well as differentiating nascent nephrons, and it is essential for kidney formation. However, the molecular functions and targets of Sall1, especially the functions and targets in the nephron progenitors, remain unknown. Here, we report that Sall1 deletion in Six2-positive nephron progenitors results in severe progenitor depletion and apoptosis of the differentiating nephrons in mice. Analysis of mice with an inducible Sall1 deletion revealed that Sall1 activates genes expressed in progenitors while repressing genes expressed in differentiating nephrons. Sall1 and Six2 co-occupied many progenitor-related gene loci, and Sall1 bound to Six2 biochemically. In contrast, Sall1 did not bind to the Wnt4 locus suppressed by Six2. Sall1-mediated repression was also independent of its binding to DNA. Thus, Sall1 maintains nephron progenitors and their derivatives by a unique mechanism, which partly overlaps but is distinct from that of Six2: Sall1 activates progenitor-related genes in Six2-positive nephron progenitors and represses gene expression in Six2-negative differentiating nascent nephrons.