Identification of a functional antioxidant response element at the HIF1A locus

Hypoxia and the endometrium: An indispensable role for HIF-1α as therapeutic strategies

Hypoxia-inducible factor 1 alpha (HIF-1α) is a major molecular mediator of the hypoxic response. In the endometrium, local hypoxic conditions induced by hormonal fluctuations and endometrial vascular remodeling contribute to the production of HIF-1α, which plays an indispensable role in a series of physiological activities, such as menstruation and metamorphosis. The sensitive regulation of HIF-1α maintains the cellular viability and regenerative capacity of the endometrium against cellular stresses induced by hypoxia and excess reactive oxygen species. In contrast, abnormal HIF-1α levels exacerbate the development of various endometrial pathologies. This knowledge opens important possibilities for the development of promising HIF-1α-centered strategies to ameliorate endometrial disease. Nonetheless, additional efforts are required to elucidate the regulatory network of endometrial HIF-1α and promote the applications of HIF-1α-centered strategies in the human endometrium. Here, we summarize the role of the HIF-1α-mediated pathway in endometrial physiology and pathology, highlight the latest HIF-1α-centered strategies for treating endometrial diseases, and improve endometrial receptivity.

Tumor promoting effect of PDLIM2 downregulation involves mitochondrial ROS, oncometabolite accumulations and HIF-1α activation

BACKGROUND

Cancer is characterized by dysregulated cellular metabolism. Thus, understanding the mechanisms underlying these metabolic alterations is important for developing targeted therapies. In this study, we investigated the pro-tumoral effect of PDZ and LIM domain 2 (PDLIM2) downregulation in lung cancer growth and its association with the accumulation of mitochondrial ROS, oncometabolites and the activation of hypoxia-inducible factor-1 (HIF-1) α in the process.

METHODS

Databases and human cancer tissue samples were analyzed to investigate the roles of PDLIM2 and HIF-1α in cancer growth. DNA microarray and gene ontology enrichment analyses were performed to determine the cellular functions of PDLIM2. Seahorse assay, flow cytometric analysis, and confocal microscopic analysis were employed to study mitochondrial functions. Oncometabolites were analyzed using liquid chromatography-mass spectrometry (LC-MS). A Lewis lung carcinoma (LLC) mouse model was established to assess the in vivo function of PDLIM2 and HIF-1α.

RESULTS

The expression of PDLIM2 was downregulated in lung cancer, and this downregulation correlated with poor prognosis in patients. PDLIM2 highly regulated genes associated with mitochondrial functions. Mechanistically, PDLIM2 downregulation resulted in NF-κB activation, impaired expression of tricarboxylic acid (TCA) cycle genes particularly the succinate dehydrogenase (SDH) genes, and mitochondrial dysfunction. This disturbance contributed to the accumulation of succinate and other oncometabolites, as well as the buildup of mitochondrial reactive oxygen species (mtROS), leading to the activation of hypoxia-inducible factor 1α (HIF-1α). Furthermore, the expression of HIF-1α was increased in all stages of lung cancer. The expression of PDLIM2 and HIF-1α was reversely correlated in lung cancer patients. In the animal study, the orally administered HIF-1α inhibitor, PX-478, significantly reduces PDLIM2 knockdown-promoted tumor growth.

CONCLUSION

These findings shed light on the complex action of PDLIM2 on mitochondria and HIF-1α activities in lung cancer, emphasizing the role of HIF-1α in the tumor-promoting effect of PDLIM2 downregulation. Additionally, they provide new insights into a strategy for precise targeted treatment by suggesting that HIF-1α inhibitors may serve as therapy for lung cancer patients with PDLIM2 downregulation.

Environmental Chemical-Induced Reactive Oxygen Species Generation and Immunotoxicity: A Comprehensive Review

Significance: Reactive oxygen species (ROS), the reactive oxygen-carrying chemicals moieties, act as pleiotropic signal transducers to maintain various biological processes/functions, including immune response. Increased ROS production leads to oxidative stress, which is implicated in xenobiotic-induced adverse effects. Understanding the immunoregulatory mechanisms and immunotoxicity is of interest to developing therapeutics against xenobiotic insults. Recent Advances: While developmental studies have established the essential roles of ROS in the establishment and proper functioning of the immune system, toxicological studies have demonstrated high ROS generation as one of the potential mechanisms of immunotoxicity induced by environmental chemicals, including heavy metals, pesticides, aromatic hydrocarbons (benzene and derivatives), plastics, and nanoparticles. Mitochondrial electron transport and various signaling components, including NADH oxidase, toll-like receptors (TLRs), NF-κB, JNK, NRF2, p53, and STAT3, are involved in xenobiotic-induced ROS generation and immunotoxicity. Critical Issues: With many studies demonstrating the role of ROS and oxidative stress in xenobiotic-induced immunotoxicity, rigorous and orthogonal approaches are needed to achieve in-depth and precise understanding. The association of xenobiotic-induced immunotoxicity with disease susceptibility and progression needs more data acquisition. Furthermore, the general methodology needs to be possibly replaced with high-throughput precise techniques. Future Directions: The progression of xenobiotic-induced immunotoxicity into disease manifestation is not well documented. Immunotoxicological studies about the combination of xenobiotics, age-related sensitivity, and their involvement in human disease incidence and pathogenesis are warranted. Antioxid. Redox Signal. 40, 691-714.

Redox-Responsive Polymeric Nanoparticle for Nucleic Acid Delivery and Cancer Therapy: Progress, Opportunities, and Challenges

Cancer development and progression of cancer are closely associated with the activation of oncogenes and loss of tumor suppressor genes. Nucleic acid drugs (e.g., siRNA, mRNA, and DNA) are widely used for cancer therapy due to their specific ability to regulate the expression of any cancer-associated genes. However, nucleic acid drugs are negatively charged biomacromolecules that are susceptible to serum nucleases and cannot cross cell membrane. Therefore, specific delivery tools are required to facilitate the intracellular delivery of nucleic acid drugs. In the past few decades, a variety of nanoparticles (NPs) are designed and developed for nucleic acid delivery and cancer therapy. In particular, the polymeric NPs in response to the abnormal redox status in cancer cells have garnered much more attention as their potential in redox-triggered nanostructure dissociation and rapid intracellular release of nucleic acid drugs. In this review, the important genes or signaling pathways regulating the abnormal redox status in cancer cells are briefly introduced and the recent development of redox-responsive NPs for nucleic acid delivery and cancer therapy is systemically summarized. The future development of NPs-mediated nucleic acid delivery and their challenges in clinical translation are also discussed.

Synthesis, antioxidant and antihypoxia activities of 6hydroxygenistein and its methylated derivatives

OBJECTIVES

Hypoxia is a common pathological phenomenon, usually caused by insufficient oxygen supply or inability to use oxygen effectively. Hydroxylated and methoxylated flavonoids have significant anti-hypoxia activity. This study aims to explore the synthesis, antioxidant and anti-hypoxia activities of 6-hydroxygenistein (6-OHG) and its methoxylated derivatives.

METHODS

The 6-OHG and its methoxylated derivatives, including 4',6,7-trimethoxy-5-hydroxyisoflavone (compound 3), 4',5,6,7-tetramethoxyisoflavone (compound 4), 4',6-imethoxy-5,7-dihydroxyisoflavone (compound 6), and 4'-methoxy-5,6,7-trihydroxyisoflavone (compound 7), were synthesized by methylation, bromination, methoxylation, and demethylation using biochanin A as raw material. The structure of these products were characterized by 1hydrogen-nuclear magnetic resonance spectroscopy (1H-NMR) and mass spectrometry (MS). The purity of these compounds was detected by high pressure chromatography (HPLC). The antioxidant activity in vitro was investigated by 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) free radical scavenging assay. PC12 cells were divided into a normal group, a hypoxia model group, rutin (1×10-9-1×10-5 mol/L) groups, and target compounds (1×10-9-1×10-5 mol/L) groups under normal and hypoxic conditions. Cell viability was detected by cell counting kit-8 (CCK-8) assay, the target compounds with excellent anti-hypoxia activity and the drug concentration at the maximum anti-hypoxia activity were screened. PC12 cells were treated with the optimal concentration of the target compound or rutin with excellent anti-hypoxia activity, and the cell morphology was observed under light microscope. The apoptotic rate was determined by flow cytometry, and the expressions of hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) were detected by Western blotting.

RESULTS

The structure of 6-OHG and its 4 methylated derivatives were correct, and the purity was all more than 97%. When the concentration was 4 mmol/L, the DPPH free radical removal rates of chemical compounds 7 and 6-OHG were 81.16% and 86.94%, respectively, which were higher than those of rutin, the positive control. The removal rates of chemical compounds 3, 4, and 6 were all lower than 20%. Compared with the normal group, the cell viability of the hypoxia model group was significantly decreased (P<0.01). Compared with the hypoxia model group, compounds 3, 4, and 6 had no significant effect on cell viability under hypoxic conditions. At all experimental concentrations, the cell viability of the 6-OHG group was significantly higher than that of the hypoxia model group (all P<0.05). The cell viability of compound 7 group at 1×10-7 and 1×10-6 mol/L was significantly higher than that of the hypoxia model group (both P<0.05). The anti-hypoxia activity of 6-OHG and compound 7 was excellent, and the optimal drug concentration was 1×10-6 and 1×10-7 mol/L. After PC12 cells was treated with 6-OHG (1×10-6 mol/L) and compound 7 (1×10-7 mol/L), the cell damage was reduced, the apoptotic rate was significantly decreased (P<0.01), and the protein expression levels of HIF-1α and VEGF were significantly decreased in comparison with the hypoxia model group (both P<0.01).

CONCLUSIONS

The optimized synthesis route can increase the yield of 6-OHG and obtain 4 derivatives by methylation and selective demethylation. 6-OHG and compound 7 have excellent antioxidant and anti-hypoxia activities, which are related to the structure of the A-ring ortho-triphenol hydroxyl group in the molecule.

Trophoblast Syncytialization: A Metabolic Crossroads

During placentation, villous cytotrophoblast (CTB) stem cells proliferate and fuse, giving rise to the multinucleated syncytiotrophoblast (STB), which represents the terminally differentiated villous layer as well as the maternal-fetal interface. The syncytiotrophoblast is at the forefront of nutrient, gas, and waste exchange while also harboring essential endocrine functions to support pregnancy and fetal development. Considering that mitochondrial dynamics and respiration have been implicated in stem cell fate decisions of several cell types and that the placenta is a mitochondria-rich organ, we will highlight the role of mitochondria in facilitating trophoblast differentiation and maintaining trophoblast function. We discuss both the process of syncytialization and the distinct metabolic characteristics associated with CTB and STB sub-lineages prior to and during syncytialization. As mitochondrial respiration is tightly coupled to redox homeostasis, we emphasize the adaptations of mitochondrial respiration to the hypoxic placental environment. Furthermore, we highlight the critical role of mitochondria in conferring the steroidogenic potential of the STB following differentiation. Ultimately, mitochondrial function and morphological changes centrally regulate respiration and influence trophoblast fate decisions through the production of reactive oxygen species (ROS), whose levels modulate the transcriptional activation or suppression of pluripotency or commitment genes.

Hypoxia-induced signaling in the cardiovascular system: pathogenesis and therapeutic targets

Hypoxia, characterized by reduced oxygen concentration, is a significant stressor that affects the survival of aerobic species and plays a prominent role in cardiovascular diseases. From the research history and milestone events related to hypoxia in cardiovascular development and diseases, The "hypoxia-inducible factors (HIFs) switch" can be observed from both temporal and spatial perspectives, encompassing the occurrence and progression of hypoxia (gradual decline in oxygen concentration), the acute and chronic manifestations of hypoxia, and the geographical characteristics of hypoxia (natural selection at high altitudes). Furthermore, hypoxia signaling pathways are associated with natural rhythms, such as diurnal and hibernation processes. In addition to innate factors and natural selection, it has been found that epigenetics, as a postnatal factor, profoundly influences the hypoxic response and progression within the cardiovascular system. Within this intricate process, interactions between different tissues and organs within the cardiovascular system and other systems in the context of hypoxia signaling pathways have been established. Thus, it is the time to summarize and to construct a multi-level regulatory framework of hypoxia signaling and mechanisms in cardiovascular diseases for developing more therapeutic targets and make reasonable advancements in clinical research, including FDA-approved drugs and ongoing clinical trials, to guide future clinical practice in the field of hypoxia signaling in cardiovascular diseases.

Wogonin Diminishes Radioresistance of Breast Cancer via Inhibition of the Nrf2/HIF-1[Formula: see text] Pathway

Radiotherapy plays a crucial role in the multimodal treatment of breast cancer. However, radioresistance poses a significant challenge to its effectiveness, hindering successful cancer therapy. Emerging evidence indicates that Nrf2 and HIF-1[Formula: see text] are critical regulators of cellular anti-oxidant responses and that their overexpression significantly promotes radioresistance. Wogonin (WG), the primary component isolated from Scutellaria baicalensis, exhibits potential antitumor and reversal of multidrug resistance activities. Nevertheless, the role of WG in radioresistance remains unclear. This study aims to explore the effects of WG on the radioresistance of breast cancer. Our results indicate that Nrf2 and HIF-1[Formula: see text] overexpression was observed in breast cancer tissues and was correlated with the histological grading of the disease. Radiation further increased the levels of Nrf2 and HIF-1[Formula: see text] in breast cancer cells. However, WG demonstrated the ability to induce cell apoptosis and reverse radioresistance by inhibiting the Nrf2/HIF-1[Formula: see text] pathway. These effects were also confirmed in xenograft mice models. Mechanistically, WG enhanced the level of the Nrf2 inhibitor Keap1 through reducing CpG methylation in the promoter region of the Keap1 gene. Consequently, the Nrf2/HIF-1[Formula: see text] pathway, along with the Nrf2- and HIF-1[Formula: see text]-dependent protective responses, were suppressed. Taken together, our findings demonstrate that WG can epigenetically regulate the Keap1 gene, inhibit the Nrf2/HIF-1[Formula: see text] pathway, induce apoptosis in breast cancer cells, and diminish acquired radioresistance. This study offers potential strategies to overcome the limitations of current radiotherapy for breast cancer.

Unraveling the Nrf2-ARE Signaling Pathway in the DF-1 Chicken Fibroblast Cell Line: Insights into T-2 Toxin-Induced Oxidative Stress Regulation

The T-2 toxin (T2) poses a major threat to the health and productivity of animals. The present study aimed to investigate the regulatory mechanism of Nrf2 derived from broilers against T2-induced oxidative damage. DF-1 cells, including those with normal characteristics, as well as those overexpressing or with a knockout of specific components, were exposed to a 24 h treatment of 50 nM T2. The primary objective was to evaluate the indicators associated with oxidative stress and the expression of downstream antioxidant factors regulated by the Nrf2-ARE signaling pathway, at both the mRNA and protein levels. The findings of this study demonstrated a noteworthy relationship between the up-regulation of the Nrf2 protein and a considerable reduction in the oxidative stress levels within DF-1 cells (p < 0.05). Furthermore, this up-regulation was associated with a notable increase in the mRNA and protein levels of antioxidant factors downstream of the Nrf2-ARE signaling pathway (p < 0.05). Conversely, the down-regulation of the Nrf2 protein was linked to a marked elevation in oxidative stress levels in DF-1 cells (p < 0.05). Additionally, this down-regulation resulted in a significant decrease in both the mRNA and protein expression of antioxidant factors (p < 0.05). This experiment lays a theoretical foundation for investigating the detrimental impacts of T2 on broiler chickens. It also establishes a research framework for employing the Nrf2 protein in broiler chicken production and breeding. Moreover, it introduces novel insights for the prospective management of oxidative stress-related ailments in the livestock and poultry industry.

Dimethylarginine Dimethylaminohydrolase - 1 expression is increased under tBHP-induced oxidative stress regulates nitric oxide production in PCa cells attenuates mitochondrial ROS-mediated apoptosis

Dimethylarginine dimethylaminohydrolase-1 (DDAH1) expression is frequently elevated in different cancers including prostate cancer (PCa) and enhances nitric oxide (NO) production in tumor cells by metabolising endogenous nitric oxide synthase (NOS) inhibitors. DDAH1 protects the PCa cells from cell death and promotes survival. In this study, we have investigated the cytoprotective role of DDAH1 and determined the mechanism of DDAH1 in protecting the cells in tumor microenvironment. Proteomic analysis of PCa cells with stable overexpression of DDAH1 has identified that oxidative stress-related activity is altered. Oxidative stress promotes cancer cell proliferation, survival and causes chemoresistance. A known inducer of oxidative stress, tert-Butyl Hydroperoxide (tBHP) treatment to PCa cells led to elevated DDAH1 level that is actively involved in protecting the PCa cells from oxidative stress induced cell damage. In PC3-DDAH1- cells, tBHP treatment led to higher mROS levels indicating that the loss of DDAH1 increases the oxidative stress and eventually leads to cell death. Under oxidative stress, nuclear Nrf2 controlled by SIRT1 positively regulates DDAH1 expression in PC3 cells. In PC3-DDAH1+ cells, tBHP induced DNA damage is well tolerated compared to wild-type cells while PC3-DDAH1- became sensitive to tBHP. In PC3 cells, tBHPexposure has increased the production of NO and GSH which may be acting as an antioxidant defence to overcome oxidative stress. Furthermore, in tBHP treated PCa cells, DDAH1 is controlling the expression of Bcl2, active PARP and caspase 3. Taken together, these results confirm that DDAH1 is involved in the antioxidant defence system and promotes cell survival.

Genomically anchored vitamin D receptor mediates an abundance of bioprotective actions elicited by its 1,25-dihydroxyvitamin D hormonal ligand

The nuclear vitamin D receptor (VDR) mediates the actions of its physiologic 1,25-dihydroxyvitamin D3 (1,25D) ligand produced in kidney and at extrarenal sites during times of physiologic and cellular stress. The ligand-receptor complex transcriptionally controls genes encoding factors that regulate calcium and phosphate sensing/transport, bone remodeling, immune function, and nervous system maintenance. With the aid of parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23), 1,25D/VDR primarily participates in an intricate network of feedback controls that govern extracellular calcium and phosphate concentrations, mainly influencing bone formation and mineralization, ectopic calcification, and indirectly supporting many fundamental roles of calcium. Beyond endocrine and intracrine effects, 1,25D/VDR signaling impacts multiple biochemical phenomena that potentially affect human health and disease, including autophagy, carcinogenesis, cell growth/differentiation, detoxification, metabolic homeostasis, and oxidative stress mitigation. Several health advantages conferred by 1,25D/VDR appear to be promulgated by induction of klotho, an anti-aging renal peptide hormone which functions as a co-receptor for FGF23 and, like 1,25D, regulates nrf2, foxo, mTOR and other cellular protective pathways. Among hundreds of genes for which expression is modulated by 1,25D/VDR either primarily or secondarily in a cell-specific manner, the resulting gene products (in addition to those expressed in the classic skeletal mineral regulatory tissues kidney, intestine, and bone), fall into multiple biochemical categories including apoptosis, cholesterol homeostasis, glycolysis, hypoxia, inflammation, p53 signaling, unfolded protein response and xenobiotic metabolism. Thus, 1,25D/VDR is a bone mineral control instrument that also signals the maintenance of multiple cellular processes in the face of environmental and genetic challenges.

Delayed cortical bone healing due to impaired nuclear Nrf2 translocation in COPD mice

The effect of the pathogenesis of chronic obstructive pulmonary disease (COPD) on bone fracture healing is unknown. Oxidative stress has been implicated in the systemic complications of COPD, and decreased activity of Nrf2 signaling, a central component of the in vivo antioxidant mechanism, has been reported. We investigated the process of cortical bone repair in a mouse model of elastase-induced emphysema by creating a drill hole and focusing on Nrf2 and found that the amount of new bone in the drill hole was reduced and bone formation capacity was decreased in the model mice. Furthermore, nuclear Nrf2 expression in osteoblasts was reduced in model mice. Sulforaphane, an Nrf2 activator, improved delayed cortical bone healing in model mice. This study indicates that bone healing is delayed in COPD mice and that impaired nuclear translocation of Nrf2 is involved in delayed cortical bone healing, suggesting that Nrf2 may be a novel target for bone fracture treatment in COPD patients.

An antioxidant response element regulates the HIF1α axis in breast cancer cells

The redox sensitive transcription factor NRF2 is a central regulator of the transcriptional response to reactive oxygen species (ROS). NRF2 is widely recognized for its ROS-responsive upregulation of antioxidant genes that are essential for mitigating the damaging effects of oxidative stress. However, multiple genome-wide approaches have suggested that NRF2's regulatory reach extends well beyond the canonical antioxidant genes, with the potential to regulate many noncanonical target genes. Recent work from our lab and others suggests HIF1A, which encodes the hypoxia-responsive transcription factor HIF1α, is one such noncanonical NRF2 target. These studies found that NRF2 activity is associated with high HIF1A expression in multiple cellular contexts, HIF1A expression is partially dependent on NRF2, and there is a putative NRF2 binding site (antioxidant response element, or ARE) approximately 30 kilobases upstream of HIF1A. These findings all support a model in which HIF1A is a direct target of NRF2, but did not confirm the functional importance of the upstream ARE in HIF1A expression. Here we use CRISPR/Cas9 genome editing to mutate this ARE in its genomic context and test the impact on HIF1A expression. We find that mutation of this ARE in a breast cancer cell line (MDA-MB-231) eliminates NRF2 binding and decreases HIF1A expression at the transcript and protein levels, and disrupts HIF1α target genes as well as phenotypes driven by these HIF1α targets. Taken together, these results indicate that this NRF2 targeted upstream ARE plays an important role in the expression of HIF1A and activity of the HIF1α axis in MDA-MB-231 cells.

Oxidative stress: A common pathological state in a high-risk population for osteoporosis

Osteoporosis is becoming a major concern in the field of public health. The process of bone loss is insidious and does not directly induce obvious symptoms. Complications indicate an irreversible decrease in bone mass. The high-risk populations of osteoporosis, including postmenopausal women, elderly men, diabetic patients and obese individuals need regular bone mineral density testing and appropriate preventive treatment. However, the primary changes in these populations are different, increasing the difficulty of effective treatment of osteoporosis. Determining the core pathogenesis of osteoporosis helps improve the efficiency and efficacy of treatment among these populations. Oxidative stress is a common pathological state secondary to estrogen deficiency, aging, hyperglycemia and hyperlipemia. In this review, we divided oxidative stress into the direct effect of reactive oxygen species (ROS) and the reduction of antioxidant enzyme activity to discuss their roles in the development of osteoporosis. ROS initiated mitochondrial apoptotic signaling and suppressed osteogenic marker expression to weaken osteogenesis. MAPK and NF-κB signaling pathways mediated the positive effect of ROS on osteoclast differentiation. Antioxidant enzymes not only eliminate the negative effects of ROS, but also directly participate in the regulation of bone metabolism. Additionally, we also described the roles of proinflammatory factors and HIF-1α under the pathophysiological changes of inflammation and hypoxia, which provided a supplement of oxidative stress-induced osteoporosis. In conclusion, our review showed that oxidative stress was a common pathological state in a high-risk population for osteoporosis. Targeted oxidative stress treatment would greatly optimize the therapeutic schedule of various osteoporosis treatments.

Methyltransferase Set7/9 as a Multifaceted Regulator of ROS Response

Reactive oxygen species (ROS) induce multiple signaling cascades in the cell and hence play an important role in the regulation of the cell's fate. ROS can cause irreversible damage to DNA and proteins resulting in cell death. Therefore, finely tuned regulatory mechanisms exist in evolutionarily diverse organisms that are aimed at the neutralization of ROS and its consequences with respect to cellular damage. The SET domain-containing lysine methyltransferase Set7/9 (KMT7, SETD7, SET7, SET9) post-translationally modifies several histones and non-histone proteins via monomethylation of the target lysines in a sequence-specific manner. In cellulo, the Set7/9-directed covalent modification of its substrates affects gene expression, cell cycle, energy metabolism, apoptosis, ROS, and DNA damage response. However, the in vivo role of Set7/9 remains enigmatic. In this review, we summarize the currently available information regarding the role of methyltransferase Set7/9 in the regulation of ROS-inducible molecular cascades in response to oxidative stress. We also highlight the in vivo importance of Set7/9 in ROS-related diseases.

The tissue-specific transcriptional landscape underlines the involvement of endothelial cells in health and disease

Endothelial cells (ECs) that line vascular and lymphatic vessels are being increasingly recognized as important to organ function in health and disease. ECs participate not only in the trafficking of gases, metabolites, and cells between the bloodstream and tissues but also in the angiocrine-based induction of heterogeneous parenchymal cells, which are unique to their specific tissue functions. The molecular mechanisms regulating EC heterogeneity between and within different tissues are modeled during embryogenesis and become fully established in adults. Any changes in adult tissue homeostasis induced by aging, stress conditions, and various noxae may reshape EC heterogeneity and induce specific transcriptional features that condition a functional phenotype. Heterogeneity is sustained via specific genetic programs organized through the combinatory effects of a discrete number of transcription factors (TFs) that, at the single tissue-level, constitute dynamic networks that are post-transcriptionally and epigenetically regulated. This review is focused on outlining the TF-based networks involved in EC specialization and physiological and pathological stressors thought to modify their architecture.

Dynamic Magneto-Softening of 3D Hydrogel Reverses Malignant Transformation of Cancer Cells and Enhances Drug Efficacy

High extracellular matrix stiffness is a prominent feature of malignant tumors associated with poor clinical prognosis. To elucidate mechanistic connections between increased matrix stiffness and tumor progression, a variety of hydrogel scaffolds with dynamic changes in stiffness have been developed. These approaches, however, are not biocompatible at high temperature, strong irradiation, and acidic/basic pH, often lack reversibility (can only stiffen and not soften), and do not allow study on the same cell population longitudinally. In this work, we develop a dynamic 3D magnetic hydrogel whose matrix stiffness can be wirelessly and reversibly stiffened and softened multiple times with different rates of change using an external magnet. With this platform, we found that matrix stiffness increased tumor malignancy including denser cell organization, epithelial-to-mesenchymal transition and hypoxia. More interestingly, these malignant transformations could be halted or reversed with matrix softening (i.e., mechanical rescue), to potentiate drug efficacy attributing to reduced solid stress from matrix and downregulation of cell mechano-transductors including YAP1. We propose that our platform can be used to deepen understanding of the impact of matrix softening on cancer biology, an important but rarely studied phenomenon.

Association of NRF2 with HIF-2α-induced cancer stem cell phenotypes in chronic hypoxic condition

The acquisition of the cancer stem cell (CSC) properties is often mediated by the surrounding microenvironment, and tumor hypoxia is considered an important factor for CSC phenotype development. High levels of NRF2 (Nuclear Factor Erythroid 2-Like 2; NFE2L2), a transcription factor that maintains cellular redox balance, have been associated with facilitated tumor growth and therapy resistance. In this study, we investigated the role of NRF2 in hypoxia-induced CSC phenotypes in colorectal cancer cells. Chronic hypoxia for 72 h resulted in CSC phenotypes, including elevation of krupple-like factor 4 (KLF4) and octamer-binding transcription factor 4 (OCT4), and an increase in cancer migration and spheroid growth with concomitant hypoxia-inducible factor 2α (HIF-2α) accumulation. All these chronic hypoxia-induced CSC properties were attenuated following HIF-2α-specific silencing. In this chronic hypoxia model, NRF2 inhibition by shRNA-based silencing or brusatol treatment blocked HIF-2α accumulation, which consequently resulted in decreased CSC marker expression and inhibition of CSC properties such as spheroid growth. In contrast, NRF2 overactivation by genetic or chemical approach enhanced the chronic hypoxia-induced HIF-2α accumulation and cancer migration. As a molecular mechanism of the NRF2-inhibition-mediated HIF-2α dysregulation, we demonstrated that miR-181a-2-3p, whose expression is elevated in NRF2-silenced cells, targeted the HIF-2α 3'UTR and subsequently suppressed the chronic hypoxia-induced HIF-2α and CSC phenotypes. The miR-181a-2-3p inhibitor treatment in NRF2-silenced cells could restore the levels of HIF-2α and CSC markers, and increased cancer migration and sphere formation under chronic hypoxia. In line with this, the miR-181a-2-3p inhibitor transfection could increase tumorigenicity of NRF2-silenced colorectal cancer cells. Collectively, our study suggests the involvement of NRF2/miR181a-2-3p signaling in the development of HIF-2α-mediated CSC phenotypes in sustained hypoxic environments.

MDM2 promotes cancer cell survival through regulating the expression of HIF-1α and pVHL in retinoblastoma

Hypoxia is an important tumor feature and hypoxia-inducible factor 1 (HIF-1) is a master regulator of cell response to hypoxia. Mouse double minute 2 homolog (MDM2) promotes cancer cell survival in retinoblastoma (RB), with the underlying mechanism remaining elusive. In this study, we investigated the role of MDM2 and its relation to HIF-1α in RB. Expression analysis on primary human RB samples showed that MDM2 expression was positively correlated with that of HIF-1α while negatively correlated with von Hippel-Lindau protein (pVHL), the regulator of HIF-1α. In agreement, RB cells with MDM2 overexpression showed increased expression of HIF-1α and decreased expression of pVHL, while cells with MDM2 siRNA knockdown or MDM2-specific inhibitor showed the opposite effect under hypoxia. Further immuno-precipitation analysis revealed that MDM2 could directly interact with pVHL and promotes its ubiquitination and degradation, which consequently led to the increase of HIF-1α. Inhibition of MDM2 and/or HIF-1α with specific inhibitors induced RB cell death and decreased the stem cell properties of primary RB cells. Taken together, our study has shown that MDM2 promotes RB survival through regulating the expression of pVHL and HIF-1α, and targeting MDM2 and/or HIF-1α represents a potential effective approach for RB treatment.

Overactivated NRF2 induces pseudohypoxia in hepatocellular carcinoma by stabilizing HIF-1α

Hypoxia-inducible factor-1α (HIF-1α) is highly expressed/activated in most hypoxic tumors including hepatocellular carcinoma (HCC). Another key transcription factor, nuclear factor erythroid 2-related factor 2 (NRF2), is also constitutively overactivated in HCC. In an attempt to determine whether HIF-1α and NRF2 could play complementary roles in HCC growth and progression, we investigated the crosstalk between these two transcription factors and underlying molecular mechanisms in cultured HCC cells and experimentally induced hepatocarcinogenesis as well as clinical settings. While silencing of HIF-1α in HepG2 human hepatoma cells did not alter the protein expression of NRF2, NRF2 knockdown markedly reduced the nuclear accumulation of HIF-1α without influencing its mRNA expression. In diethylnitrosamine-induced hepatocarcinogenesis in wild type mice, there was elevated NRF2 expression with concomitant upregulation of HIF-1α. However, this was abolished in Nrf2 knockout mice. NRF2 and HIF-1α co-localized and physically interacted with each other as assessed by in situ proximity ligation and immunoprecipitation assays. In addition, the interaction between NRF2 and HIF-1α as well as their overexpression was found in tumor specimens obtained from HCC patients. In normoxia, HIF-1α undergoes hydroxylation by a specific HIF-prolyl hydroxylase domain protein (PHD), which facilitates ubiquitination and proteasomal degradation of HIF-1α. NRF2 contributes to pseudohypoxia, by directly binding to the oxygen-dependent degradation (ODD) domain of HIF-1α, which hampers the PHD2-mediated hydroxylation, concomitant recruitment of von-Hippel-Lindau and ubiquitination of HIF-1α.

In Vitro Analysis of Biological Activity of Circulating Cell-Free DNA Isolated from Blood Plasma of Schizophrenic Patients and Healthy Controls-Part 2: Adaptive Response

Oxidized in vitro genomic DNA (gDNA) is known to launch an adaptive response in human cell cultures. The cfDNA extracted from the plasma of schizophrenic patients (sz-cfDNA) and healthy controls (hc-cfDNA) contains increased amounts of 8-oxodG, a DNA-oxidation marker. The aim of the research was answering a question: can the human cfDNA isolated from blood plasma stimulate the adaptive response in human cells? In vitro responses of ten human skin fibroblasts (HSFs) and four peripheral blood mononuclear cell (PBMC) lines after 1-24 h of incubation with sz-cfDNA, gDNA and hc-cfDNA containing different amounts of 8-oxodG were examined. Expressions of RNA of eight genes (NOX4, NFE2L2, SOD1, HIF1A, BRCA1, BRCA2, BAX and BCL2), six proteins (NOX4, NRF2, SOD1, HIF1A, γH2AX and BRCA1) and DNA-oxidation marker 8-oxodG were analyzed by RT-qPCR and flow cytometry (when analyzing the data, a subpopulation of lymphocytes (PBL) was identified). Adding hc-cfDNA or sz-cfDNA to HSFs or PBMC media in equal amounts (50 ng/mL, 1-3 h) stimulated transient synthesis of free radicals (ROS), which correlated with an increase in the expressions of NOX4 and SOD1 genes and with an increase in the levels of the markers of DNA damage γH2AX and 8-oxodG. ROS and DNA damage induced an antioxidant response (expression of NFE2L2 and HIF1A), DNA damage response (BRCA1 and BRCA2 gene expression) and anti-apoptotic response (changes in BAX and BCL2 genes expression). Heterogeneity of cells of the same HSFs or PBL population was found with respect to the type of response to (sz,hc)-cfDNA. Most cells responded to oxidative stress with an increase in the amount of NRF2 and BRCA1 proteins along with a moderate increase in the amount of NOX4 protein and a low amount of 8-oxodG oxidation marker. However, upon the exposure to (sz,hc)-cfDNA, the size of the subpopulation with apoptosis signs (high DNA damage degree, high NOX4 and low NRF2 and BRCA1 levels) also increased. No significant difference between the responses to sz-cfDNA and hc-cfDNA was observed. Sz-cfDNA and hc-cfDNA showed similarly high bioactivity towards fibroblasts and lymphocytes. Conclusion: In cultured human cells, hc-cfDNA and sz-cfDNA equally stimulated an adaptive response aimed at launching the antioxidant, repair, and anti-apoptotic processes. The mediator of the development of the adaptive response are ROS produced by, among others, NOX4 and SOD1 enzymes.

Low dimensional nanomaterials for treating acute kidney injury

Acute kidney injury (AKI) is one of the most common severe complications among hospitalized patients. In the absence of specific drugs to treat AKI, hemodialysis remains the primary clinical treatment for AKI patients. AKI treatment has received significant attention recently due to the excellent drug delivery capabilities of low-dimensional nanomaterials (LDNs) and their unique therapeutic effects. Diverse LDNs have been proposed to treat AKI, with promising results and the potential for future clinical application. This article aims to provide an overview of the pathogenesis of AKI and the recent advances in the treatment of AKI using different types of LDNs. In addition, it is intended to provide theoretical support for the design of LDNs and implications for AKI treatment.

Breast Tumor Cell-Stimulated Bone Marrow-Derived Mesenchymal Stem Cells Promote the Sprouting Capacity of Endothelial Cells by Promoting VEGF Expression, Mediated in Part through HIF-1α Increase

Simple Summary

ROS and JAK/Stat3 cooperatively upregulate the expression of HIF-1α in bone marrow-derived mesenchymal stem cells under normoxic conditions in response to breast tumor cells. The upregulation of HIF-1α contributes in part to the increase in VEGF expression in the bone marrow-derived mesenchymal stem cells. Bone marrow-derived mesenchymal stem cells improve the angiogenic sprouting capacity of mature endothelial cells in a VEGF-dependent manner.

Abstract

Breast tumor cells recruit bone marrow-derived mesenchymal stem cells (BM-MSCs) and alter their cellular characteristics to establish a tumor microenvironment. BM-MSCs enhance tumor angiogenesis through various mechanisms. We investigated the mechanisms by which BM-MSCs promote angiogenesis in response to breast tumor. Conditioned media from MDA-MB-231 (MDA CM) and MCF7 (MCF7 CM) breast tumor cells were used to mimic breast tumor conditions. An in vitro spheroid sprouting assay using human umbilical vein endothelial cells (HUVECs) was conducted to assess the angiogenesis-stimulating potential of BM-MSCs in response to breast tumors. The ROS inhibitor N-acetylcysteine (NAC) and JAK inhibitor ruxolitinib attenuated increased HIF-1α in BM-MSCs in response to MDA CM and MCF7 CM. HIF-1α knockdown or HIF-1β only partially downregulated VEGF expression and, therefore, the sprouting capacity of HUVECs in response to conditioned media from BM-MSCs treated with MDA CM or MCF7 CM. Inactivation of the VEGF receptor using sorafenib completely inhibited the HUVECs’ sprouting. Our results suggest that increased HIF-1α expression under normoxia in BM-MSCs in response to breast tumor cells is mediated by ROS and JAK/Stat3, and that both HIF-1α-dependent and -independent mechanisms increase VEGF expression in BM-MSCs to promote the angiogenic sprouting capacity of endothelial cells in a VEGF-dependent manner.

The impact of COVID-19 on populations living at high altitude: Role of hypoxia-inducible factors (HIFs) signaling pathway in SARS-CoV-2 infection and replication

Cases of coronavirus disease 2019 (COVID-19) have been reported worldwide. However, one epidemiological report has claimed a lower incidence of the disease in people living at high altitude (&gt;2,500 m), proposing the hypothesis that adaptation to hypoxia may prove to be advantageous with respect to SARS-CoV-2 infection. This publication was initially greeted with skepticism, because social, genetic, or environmental parametric variables could underlie a difference in susceptibility to the virus for people living in chronic hypobaric hypoxia atmospheres. Moreover, in some patients positive for SARS-CoV-2, early post-infection ‘happy hypoxia” requires immediate ventilation, since it is associated with poor clinical outcome. If, however, we accept to consider the hypothesis according to which the adaptation to hypoxia may prove to be advantageous with respect to SARS-CoV-2 infection, identification of the molecular rational behind it is needed. Among several possibilities, HIF-1 regulation appears to be a molecular hub from which different signaling pathways linking hypoxia and COVID-19 are controlled. Interestingly, HIF-1α was reported to inhibit the infection of lung cells by SARS-CoV-2 by reducing ACE2 viral receptor expression. Moreover, an association of the rs11549465 variant of HIF-1α with COVID-19 susceptibility was recently discovered. Here, we review the evidence for a link between HIF-1α, ACE2 and AT1R expression, and the incidence/severity of COVID-19. We highlight the central role played by the HIF-1α signaling pathway in the pathophysiology of COVID-19.

Genetic alterations and oxidative stress in T cell lymphomas

T cell lymphomas encompass a diverse group of Non-Hodgkin lymphomas with a wide spectrum of clinical, immunological and pathological manifestations. In the last two decades there has been a progress in our understanding of the cell of origin, genetic abnormalities and their impact on behaviour in T cell lymphomas. Genetic alterations are one of the critical drivers of the pathogenesis of T cell lymphoma. Disease progression has been correlated with multiple genetic abnormalities where malignant clones arise primarily out of the host immune surveillance arsenal. There are many cellular processes involved in disease development, and some of them are T cell signaling, differentiation, epigenetic modifications, and immune regulation. Modulation of these crucial pathways via genetic mutations and chromosomal abnormalities possessing either point or copy number mutations helps tumor cells to develop a niche favourable for their growth via metabolic alterations. Several metabolic pathways especially regulation of redox homeostasis is critical in pathogenesis of lymphoma. Disruption of redox potential and induction of oxidative stress renders malignant cells vulnerable to mitochondrial damage and triggers apoptotic pathways causing cell death. Targeting genetic abnormalities and oxidative stress along with current treatment regime have the potential for improved therapeutics and presents new combination approaches towards selective treatment of T cell lymphomas.

A Natural Gas Fermentation Bacterial Meal (FeedKind®) as a Functional Alternative Ingredient for Fishmeal in Diet of Largemouth Bass, Micropterus salmoides

A 10-week growth study was conducted to evaluate the effect of a natural gas fermentation bacterial meal (FeedKind^®, FK) as a fishmeal (FM) alternative in largemouth bass (Micropterus salmoides) (48.0 ± 0.03 g). Four isonitrogenous and isoenergetic diets were formulated including one commercial control (C, 42% FM) and three experimental diets with gradient FK of 3% (FK3, 29%FM), 6% (FK6, 26%FM) and 9% (FK9, 23%FM), respectively. FK-fed groups showed significantly higher SR than that of C group. The WGR and SGR of fish fed FK3 and FK6 were significantly higher than those of FK9, but not statistical different from the C group. FK-fed groups showed higher apparent digestibility coefficients of dry matter and nutrients. Further, FK-fed groups increased the ratio of SOD/MDA in the plasma and liver, and the upregulation of intestinal Keap1 and downregulation of HIF1α was found in FK3. Furthermore, FK-fed groups showed higher microbial richness and diversity. Pearson correlation analysis found that antioxidant relevant biomarkers were negatively correlated with the relative abundance of certain potential beneficial bacteria. In conclusion, supplemented up to 3–6% FK replacing FM in a low FM diet of largemouth bass could increase growth, survival rate, antioxidant capacity, and improve gut microbiota.

Glutor, a Glucose Transporter Inhibitor, Exerts Antineoplastic Action on Tumor Cells of Thymic Origin: Implication of Modulated Metabolism, Survival, Oxidative Stress, Mitochondrial Membrane Potential, pH Homeostasis, and Chemosensitivity

Neoplastic cells overexpress glucose transporters (GLUT), particularly GLUT1 and GLUT3, to support altered metabolism. Hence, novel strategies are being explored to effectively inhibit GLUTs for a daunting interference of glucose uptake. Glutor, a piperazine-2-one derivative, is a newly reported pan-GLUT inhibitor with a promising antineoplastic potential. However, several aspects of the underlying mechanisms remain obscure. To understand this better, tumor cells of thymic origin designated as Dalton's lymphoma (DL) were treated with glutor and analyzed for survival and metabolism regulatory molecular events. Treatment of tumor cells with glutor caused a decrease in cell survival with augmented induction of apoptosis. It also caused a decrease in glucose uptake associated with altered expression of GLUT1 and GLUT3. HIF-1α, HK-2, LDH-A, and MCT1 also decreased with diminished lactate production and deregulated pH homeostasis. Moreover, glutor treatment modulated the expression of cell survival regulatory molecules p53, Hsp70, IL-2 receptor CD25, and C-myc along with mitochondrial membrane depolarization, increased intracellular ROS expression, and altered Bcl-2/BAX ratio. Glutor also enhanced the chemosensitivity of tumor cells to cisplatin, accompanied by decreased MDR1 expression. Adding fructose to the culture medium containing glutor reversed the latter's inhibitory action on tumor cell survival. These results demonstrate that in addition to inhibited glucose uptake, modulated tumor growth regulatory molecular pathways are also implicated in the manifestation of the antineoplastic action of glutor. Thus, the novel findings of this study will have a long-lasting clinical significance in evaluating and optimizing the use of glutor in anticancer therapeutic strategies.

HIF-1α and Nrf2 regulates hypoxia induced overexpression of DDAH1 through promoter activation in prostate cancer

Dimethylarginine dimethylaminohydrolase-1 (DDAH1) is overexpressed in prostate cancer (PCa) and promotes PCa progression in in vivo through the ADMA-NO pathway by degrading nitric oxide synthase (NOS) inhibitors such as asymmetric dimethylarginine (ADMA) and monomethylamine arginine (L-NMMA). In this study, we investigated the molecular mechanism involved in the overexpression of DDAH1 in PCa and examined its potential role as a therapeutic target. We observed that DDAH1expression is elevated in PCa (PC3, LNCaP, and DU145) cell lines under hypoxia. ChIP and reporter assay results confirmed that DDAH1 expression is positively regulated by HIF-1α through directly binding to the hypoxia response elements (HRE) located within the promoter region between - 1242/- 1238 upstream of its transcription start site (TSS). Under hypoxia, HIF-1α is translocated into the nucleus and activates its target gene expression in PC3 cells. Interestingly, in the event of HIF-1α inhibition or siRNA-mediated knockdown, an alternative transcription factor Nrf2 promotes DDAH1 expression through antioxidant response elements (AREs) on its promoter. ChIP assay results showed that Nrf2 binds to AREs located between -1016 / -1008 bp from the TSS of DDAH1. Furthermore, knockdown of PCa therapeutic target HSP90, an essential co-factor for both HIF-1α and Nrf2 causes attenuation of hypoxia induced DDAH1 overexpression in PCa cells. These results demonstrate that hypoxia induced upregulation of DDAH1 expression is positively regulated by HIF-1α and Nrf2 in association with HSP90. Therefore, targeting tumor angiogenesis promoting DDAH1 along with standard androgen receptor (AR) targeted therapy may offer an effective strategy to prevent PCa progression.

Vitamin D and Hypoxia: Points of Interplay in Cancer

Vitamin D is a hormone that, through its action, elicits a broad spectrum of physiological responses ranging from classic to nonclassical actions such as bone morphogenesis and immune function. In parallel, many studies describe the antiproliferative, proapoptotic, antiangiogenic effects of calcitriol (the active hormonal form) that contribute to its anticancer activity. Additionally, epidemiological data signify the inverse correlation between vitamin D levels and cancer risk. On the contrary, tumors possess several adaptive mechanisms that enable them to evade the anticancer effects of calcitriol. Such maladaptive processes are often a characteristic of the cancer microenvironment, which in solid tumors is frequently hypoxic and elicits the overexpression of Hypoxia-Inducible Factors (HIFs). HIF-mediated signaling not only contributes to cancer cell survival and proliferation but also confers resistance to anticancer agents. Taking into consideration that calcitriol intertwines with signaling events elicited by the hypoxic status cells, this review examines their interplay in cellular signaling to give the opportunity to better understand their relationship in cancer development and their prospect for the treatment of cancer.

Antioxidant Responses Induced by Short-Term Activity–Estivation–Arousal Cycle in Pomacea canaliculata

Long-term estivation (45 days) in the apple snail Pomacea canaliculata induces an increase of non-enzymatic antioxidants, such as uric acid and reduced glutathione (GSH), which constitutes an alternative to the adaptive physiological strategy of preparation for oxidative stress (POS). Here, we studied markers of oxidative stress damage, uric acid levels, and non-enzymatic antioxidant capacity, enzymatic antioxidant defenses, such as superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST), and transcription factors expression [forkhead box protein O (FOXO), hypoxia-inducible factor-1 alpha (HIF1α), and nuclear factor erythroid 2-related factor 2 (Nrf2)] in control active animals, 7-day estivating and aroused snails, in digestive gland, gill, and lung tissue samples. In the digestive gland, SOD and CAT activities significantly increased after estivation and decreased during arousal. Meanwhile, GST activity decreased significantly during the activity–estivation–arousal cycle. Gill CAT activity increased significantly at 7 days of estivation, and it decreased during arousal. In the lung, the CAT activity level increased significantly during the cycle. FOXO upregulation was observed in the studied tissues, decreasing its expression only in the gill of aroused animals during the cycle. HIF1α and Nrf2 transcription factors decreased their expression during estivation in the gill, while in the lung and the digestive gland, both transcription factors did not show significant changes. Our results showed that the short-term estivation induced oxidative stress in different tissues of P. canaliculata thereby increasing overall antioxidant enzymes activity and highlighting the role of FOXO regulation as a possible underlying mechanism of the POS strategy.

Bioactivity of Inhaled Methane and Interactions With Other Biological Gases

A number of studies have demonstrated explicit bioactivity for exogenous methane (CH₄), even though it is conventionally considered as physiologically inert. Other reports cited in this review have demonstrated that inhaled, normoxic air-CH₄ mixtures can modulate the in vivo pathways involved in oxidative and nitrosative stress responses and key events of mitochondrial respiration and apoptosis. The overview is divided into two parts, the first being devoted to a brief review of the effects of biologically important gases in the context of hypoxia, while the second part deals with CH₄ bioactivity. Finally, the consequence of exogenous, normoxic CH₄ administration is discussed under experimental hypoxia- or ischaemia-linked conditions and in interactions between CH₄ and other biological gases, with a special emphasis on its versatile effects demonstrated in pulmonary pathologies.

Disruption of Circadian Rhythm Genes in Obstructive Sleep Apnea Patients-Possible Mechanisms Involved and Clinical Implication

Obstructive sleep apnea (OSA) is a chronic condition characterized by recurrent pauses in breathing caused by the collapse of the upper airways, which results in intermittent hypoxia and arousals during the night. The disorder is associated with a vast number of comorbidities affecting different systems, including cardiovascular, metabolic, psychiatric, and neurological complications. Due to abnormal sleep architecture, OSA patients are at high risk of circadian clock disruption, as has been reported in several recent studies. The circadian clock affects almost all daily behavioral patterns, as well as a plethora of physiological processes, and might be one of the key factors contributing to OSA complications. An intricate interaction between the circadian clock and hypoxia may further affect these processes, which has a strong foundation on the molecular level. Recent studies revealed an interaction between hypoxia-inducible factor 1 (HIF-1), a key regulator of oxygen metabolism, and elements of circadian clocks. This relationship has a strong base in the structure of involved elements, as HIF-1 as well as PER, CLOCK, and BMAL, belong to the same Per-Arnt-Sim domain family. Therefore, this review summarizes the available knowledge on the molecular mechanism of circadian clock disruption and its influence on the development and progression of OSA comorbidities.

Anemopsis californica Attenuates Photoaging by Regulating MAPK, NRF2, and NFATc1 Signaling Pathways

Long-term exposure of the skin to solar radiation causes chronic inflammation and oxidative stress, which accelerates collagen degradation. This contributes to the formation of wrinkles and dark spots, skin fragility, and even skin cancer. In this study, Anemopsis californica (AC), a herb from North America that is well known for treating microorganism infection and promoting wound healing, was investigated for its photoprotective effects. The biological effects of AC were studied on two in vitro models, namely, lipopolysaccharide (LPS)-induced macrophages and ultraviolet B (UVB)-irradiated dermal fibroblasts, to characterize its underlying molecular mechanisms. The results showed that AC decreased the mRNA levels of inflammatory mediators in sensitized macrophages, including cytokines, inducible nitric oxide synthase (iNOS), and cyclooxygenase (COX-2). Moreover, AC alleviated UVB-induced photoaging in dermal fibroblasts by restoring procollagen synthesis. This resulted from the regulation of excessive reactive oxygen species (ROS) by AC, which was mediated by the activation of the antioxidative system nuclear factor erythroid 2-related factor 2 (NRF2). AC also alleviated oxidative stress and inflammatory responses by inhibiting the phosphorylation of mitogen-activated protein kinase (MAPK) and interfering with the nuclear translocation of the immune regulator nuclear factor of activated T-cells 1 (NFATc1). In conclusion, the protective effects of AC on skin cellular components suggested that it has the potential for use in the development of drugs and cosmetics that protect the skin from UVB-induced chronic inflammation and aging.

The Programming of Antioxidant Capacity, Immunity, and Lipid Metabolism in Dojo Loach (Misgurnus anguillicaudatus) Larvae Linked to Sodium Chloride and Hydrogen Peroxide Pre-treatment During Egg Hatching

Non-nutritional stress during early life period has been reported to promote the metabolic programming in fish induced by nutritional stimulus. Sodium chloride (NaCl) and hydrogen peroxide (H₂O₂) have been widely applied during fish egg hatching, but the influences on health and metabolism of fish in their later life remain unknown. In the present study, H₂O₂ treatment at 400mg/L but not 200mg/L significantly increased the loach hatchability and decreased the egg mortality, while NaCl treatment at 1,000 and 3,000mg/L showed no significant influences on the loach hatchability nor egg mortality. Further studies indicated that 400mg/L H₂O₂ pre-treatment significantly enhanced the antioxidant capacity and the mRNA expression of genes involved in immune response of loach larvae, accompanied by the increased expression of genes involved in fish early development. However, the expression of most genes involved in lipid metabolism, including catabolism and anabolism of loach larvae, was significantly upregulated after 200mg/L H₂O₂ pre-treatment. NaCl pre-treatment also increased the expression of antioxidant enzymes; however, only the expression of C1q within the detected immune-related genes was upregulated in loach larvae. One thousand milligram per liter NaCl pre-treatment significantly increased the expression of LPL and genes involved in fish early development. Thus, our results suggested the programming roles of 400mg/L H₂O₂ pre-treatment during egg hatching in enhancing antioxidant capacity and immune response of fish larvae via promoting fish early development.

BACH1, the master regulator of oxidative stress, has a dual effect on CFTR expression

The cystic fibrosis transmembrane conductance regulator (CFTR) gene lies within a topologically associated domain (TAD) in which multiple cis-regulatory elements (CREs) and transcription factors (TFs) regulate its cell-specific expression. The CREs are recruited to the gene promoter by a looping mechanism that depends upon both architectural proteins and specific TFs. An siRNA screen to identify TFs coordinating CFTR expression in airway epithelial cells suggested an activating role for BTB domain and CNC homolog 1 (BACH1). BACH1 is a ubiquitous master regulator of the cellular response to oxidative stress. Here, we show that BACH1 may have a dual effect on CFTR expression by direct occupancy of CREs at physiological oxygen (∼8%), while indirectly modulating expression under conditions of oxidative stress. Hence BACH1, can activate or repress the same gene, to fine tune expression in response to environmental cues such as cell stress. Furthermore, our 4C-seq data suggest that BACH1 can also directly regulate CFTR gene expression by modulating locus architecture through occupancy at known enhancers and structural elements, and depletion of BACH1 alters the higher order chromatin structure.

Impact of Nuclear Factor Erythroid 2-Related Factor 2 in Hepatocellular Carcinoma: Cancer Metabolism and Immune Status

We examined phosphorylated nuclear factor erythroid 2–related factor 2 (P‐NRF2) expression in surgically resected primary hepatocellular carcinoma (HCC) and investigated the association of P‐NRF2 expression with clinicopathological features and patient outcome. We also evaluated the relationship among NRF2, cancer metabolism, and programmed death ligand 1 (PD‐L1) expression. In this retrospective study, immunohistochemical staining of P‐NRF2 was performed on the samples of 335 patients who underwent hepatic resection for HCC. Tomography/computed tomography using fluorine‐18 fluorodeoxyglucose was performed, and HCC cell lines after NRF2 knockdown were analyzed by array. We also analyzed the expression of PD‐L1 after hypoxia inducible factor 1α (HIF1A) knockdown in NRF2‐overexpressing HCC cell lines. Samples from 121 patients (36.1%) were positive for P‐NRF2. Positive P‐NRF2 expression was significantly associated with high alpha‐fetoprotein (AFP) expression, a high rate of poor differentiation, and microscopic intrahepatic metastasis. In addition, positive P‐NRF2 expression was an independent predictor for recurrence‐free survival and overall survival. NRF2 regulated glucose transporter 1, hexokinase 2, pyruvate kinase isoenzymes L/R, and phosphoglycerate kinase 1 expression and was related to the maximum standardized uptake value. PD‐L1 protein expression levels were increased through hypoxia‐inducible factor 1α after NRF2 overexpression in HCC cells. Conclusions: Our large cohort study revealed that P‐NRF2 expression in cancer cells was associated with clinical outcome in HCC. Additionally, we found that NRF2 was located upstream of cancer metabolism and tumor immunity.

Protein co-expression network-based profiles revealed from laser-microdissected cancerous cells of lung squamous-cell carcinomas

No therapeutic targets have been identified for lung squamous cell cancer (SqCC) which is the second most prevalent lung cancer because its molecular profiles remain unclear. This study aimed to unveil disease-related protein networks by proteomic and bioinformatic assessment of laser-microdissected cancerous cells from seven SqCCs compared with eight representative lung adenocarcinomas. We identified three network modules significant to lung SqCC using weighted gene co-expression network analysis. One module was intrinsically annotated to keratinization and cell proliferation of SqCC, accompanied by hypoxia-induced aerobic glycolysis, in which key regulators were activated (HIF1A, ROCK2, EFNA1-5) and highly suppressed (KMT2D). The other two modules were significant for translational initiation, nonsense-mediated mRNA decay, inhibited cell death, and interestingly, eIF2 signaling, in which key regulators, MYC and MLXIPL, were highly activated. Another key regulator LARP1, the master regulator in cap-dependent translation, was highly suppressed although upregulations were observed for hub proteins including EIF3F and LARP1 targeted ribosomal proteins, among which PS25 is the key ribosomal protein in IRES-dependent translation. Our results suggest an underlying progression mechanism largely caused by switching to the cap-independent, IRES-dependent translation of mRNA subsets encoding oncogenic proteins. Our findings may help to develop therapeutic strategies to improve patient outcomes.

Emerging role of ferroptosis in breast cancer: New dawn for overcoming tumor progression

Breast cancer has become a serious threat to women's health. Cancer progression is mainly derived from resistance to apoptosis induced by procedures or therapies. Therefore, new drugs or models that can overcome apoptosis resistance should be identified. Ferroptosis is a recently identified mode of cell death characterized by excess reactive oxygen species-induced lipid peroxidation. Since ferroptosis is distinct from apoptosis, necrosis and autophagy, its induction successfully eliminates cancer cells that are resistant to other modes of cell death. Therefore, ferroptosis may become a new direction around which to design breast cancer treatment. Unfortunately, the complete appearance of ferroptosis in breast cancer has not yet been fully elucidated. Furthermore, whether ferroptosis inducers can be used in combination with traditional anti- breast cancer drugs is still unknown. Moreover, a summary of ferroptosis in breast cancer progression and therapy is currently not available. In this review, we discuss the roles of ferroptosis-associated modulators glutathione, glutathione peroxidase 4, iron, nuclear factor erythroid-2 related factor-2, superoxide dismutases, lipoxygenase and coenzyme Q in breast cancer. Furthermore, we provide evidence that traditional drugs against breast cancer induce ferroptosis, and that ferroptosis inducers eliminate breast cancer cells. Finally, we put forward prospect of using ferroptosis inducers in breast cancer therapy, and predict possible obstacles and corresponding solutions. This review will deepen our understanding of the relationship between ferroptosis and breast cancer, and provide new insights into breast cancer-related therapeutic strategies.

Synthetic Retinoids as Potential Therapeutics in Prostate Cancer-An Update of the Last Decade of Research: A Review

Prostate cancer (PC) is the second most common tumor in males. The search for appropriate therapeutic options against advanced PC has been in process for several decades. Especially after cessation of the effectiveness of hormonal therapy (i.e., emergence of castration-resistant PC), PC management options have become scarce and the prognosis is poor. To overcome this stage of disease, an array of natural and synthetic substances underwent investigation. An interesting and promising class of compounds constitutes the derivatives of natural retinoids. Synthesized on the basis of the structure of retinoic acid, they present unique and remarkable properties that warrant their investigation as antitumor drugs. However, there is no up-to-date compilation that consecutively summarizes the current state of knowledge about synthetic retinoids with regard to PC. Therefore, in this review, we present the results of the experimental studies on synthetic retinoids conducted within the last decade. Our primary aim is to highlight the molecular targets of these compounds and to identify their potential promise in the treatment of PC.

The Role of HIF1α-PFKFB3 Pathway in Diabetic Retinopathy

Diabetic retinopathy (DR) is the leading cause of blindness for adults in developed countries. Both microvasculopathy and neurodegeneration are implicated in mechanisms of DR development, with neuronal impairment preceding microvascular abnormalities, which is often underappreciated in the clinic. Most current therapeutic strategies, including anti-vascular endothelial growth factor (anti-VEGF)-antibodies, aim at treating the advanced stages (diabetic macular edema and proliferative diabetic retinopathy) and fail to target the neuronal deterioration. Hence, new therapeutic approach(es) intended to address both vascular and neuronal impairment are urgently needed. The hypoxia-inducible factor 1α (HIF1α)-6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) pathway is critically implicated in the islet pathology of diabetes. Recent evidence highlighted the pathway relevance for pathologic angiogenesis and neurodegeneration, two key aspects in DR. PFKFB3 is key to the sprouting angiogenesis, along with VEGF, by determining the endothelial tip-cell competition. Also, PFKFB3-driven glycolysis compromises the antioxidative capacity of neurons leading to neuronal loss and reactive gliosis. Therefore, the HIF1α-PFKFB3 signaling pathway is unique as being a pervasive pathological component across multiple cell types in the retina in the early as well as late stages of DR. A metabolic point-of-intervention based on HIF1α-PFKFB3 targeting thus deserves further consideration in DR.

Transcriptional reprogramming by oxidative stress occurs within a predefined chromatin accessibility landscape

Reactive oxygen species (ROS) are important signaling molecules in many physiological processes, yet excess ROS leads to cell damage and can lead to pathology. Accordingly, cells need to maintain tight regulation of ROS levels, and ROS-responsive transcriptional reprogramming is central to this process. Although it has long been recognized that oxidative stress leads to rapid, significant changes in gene expression, the impact of oxidative stress on the underlying chromatin accessibility landscape remained unclear. Here, we asked whether ROS-responsive transcriptional reprogramming is accompanied by reprogramming of the chromatin environment in MCF7 human breast cancer cells. Using a time-course exposure to multiple inducers of oxidative stress, we determined that the widespread ROS-responsive changes in gene expression induced by ROS occur with minimal changes to the chromatin environment. While we did observe changes in chromatin accessibility, these changes were: (1) far less numerous than gene expression changes after oxidative stress, and (2) occur within pre-existing regions of accessible chromatin. Transcription factor (TF) footprinting analysis of our ATAC-seq experiments identified 5 TFs or TF families with evidence for ROS-responsive changes in DNA binding: NRF2, AP-1, p53, NFY, and SP/KLF. Importantly, several of these (AP-1, NF-Y, and SP/KLF factors) have not been previously implicated as widespread regulators in the response to ROS. In summary, we have characterized genome-wide changes in gene expression and chromatin accessibility in response to ROS treatment of MCF7 cells, and we have found that regulation of the large-scale transcriptional response to excess ROS is primarily constrained by the cell's pre-existing chromatin landscape.

Recent insights on astrocyte mechanisms in CNS homeostasis, pathology, and repair

Astrocytes play essential roles in development, homeostasis, injury, and repair of the central nervous system (CNS). Their development is tightly regulated by distinct spatial and temporal cues during embryogenesis and into adulthood throughout the CNS. Astrocytes have several important responsibilities such as regulating blood flow and permeability of the blood-CNS barrier, glucose metabolism and storage, synapse formation and function, and axon myelination. In CNS pathologies, astrocytes also play critical parts in both injury and repair mechanisms. Upon injury, they undergo a robust phenotypic shift known as "reactive astrogliosis," which results in both constructive and deleterious outcomes. Astrocyte activation and migration at the site of injury provides an early defense mechanism to minimize the extent of injury by enveloping the lesion area. However, astrogliosis also contributes to the inhibitory microenvironment of CNS injury and potentiate secondary injury mechanisms, such as inflammation, oxidative stress, and glutamate excitotoxicity, which facilitate neurodegeneration in CNS pathologies. Intriguingly, reactive astrocytes are increasingly a focus in current therapeutic strategies as their activation can be modulated toward a neuroprotective and reparative phenotype. This review will discuss recent advancements in knowledge regarding the development and role of astrocytes in the healthy and pathological CNS. We will also review how astrocytes have been genetically modified to optimize their reparative potential after injury, and how they may be transdifferentiated into neurons and oligodendrocytes to promote repair after CNS injury and neurodegeneration.

Profiling of Primary and Mature miRNA Expression in Atherosclerosis-Associated Cell Types

[Figure: see text].

The glyco-redox interplay: Principles and consequences on the role of reactive oxygen species during protein glycosylation

Reactive oxygen species (ROS) carry out prime physiological roles as intracellular signaling agents, yet pathologically high concentrations of ROS cause irreversible damage to biomolecules, alter cellular programs and contribute to various diseases. While decades of intensive research have identified redox-related patterns and signaling pathways, very few addressed how the glycosylation machinery senses and responds to oxidative stress. A common trait among ROS and glycans residing on glycoconjugates is that they are both highly dynamic, as they are quickly fine-tuned in response to stressors such as inflammation, cancer and infectious diseases. On this account, the delicate balance of the redox potential, which is tightly regulated by dozens of enzymes including NOXs, and the mitochondrial electron transport chain as well as the fluidity of glycan biosynthesis resulting from the cooperation of glycosyltransferases, glycosidases, and nucleotide sugar transporters, is paramount to cell survival. Here, we review the broad spectrum of the interplay between redox changes and glycosylation with respect to their principle consequences on human physiology.

Retinal oxidative stress activates the NRF2/ARE pathway: An early endogenous protective response to ocular hypertension

Oxidative stress contributes to degeneration of retinal ganglion cells and their axons in glaucoma, a leading cause of irreversible blindness worldwide, through sensitivity to intraocular pressure (IOP). Here, we investigated early elevations in reactive oxygen species (ROS) and a role for the NRF2-KEAP1-ARE endogenous antioxidant response pathway using microbead occlusion to elevate IOP in mice. ROS levels peaked in the retina at 1- and 2-wks following IOP elevation and remained elevated out to 5-wks. Phosphorylation of NRF2 and antioxidant gene transcription and protein levels increased concomitantly at 2-wks after IOP elevation, along with phosphorylation of PI3K and AKT. Inhibiting PI3K or AKT signaling prevented NRF2 phosphorylation and reduced transcription of antioxidant-regulated genes. Ocular hypertensive mice lacking Nrf2 had elevated ROS and a diminished increase in antioxidant gene expression. They also exhibited earlier axon degeneration and loss of visual function. In conclusion, the NRF2-KEAP1-ARE pathway is endogenously activated early in ocular hypertension due to phosphorylation of NRF2 by the PI3K/AKT pathway and serves to slow the onset of axon degeneration and vision loss in glaucoma. These data suggest that exogenous activation of this pathway might further slow glaucomatous neurodegeneration.

Sulforaphane Impact on Reactive Oxygen Species (ROS) in Bladder Carcinoma

Sulforaphane (SFN) is a natural glucosinolate found in cruciferous vegetables that acts as a chemopreventive agent, but its mechanism of action is not clear. Due to antioxidative mechanisms being thought central in preventing cancer progression, SFN could play a role in oxidative processes. Since redox imbalance with increased levels of reactive oxygen species (ROS) is involved in the initiation and progression of bladder cancer, this mechanism might be involved when chemoresistance occurs. This review summarizes current understanding regarding the influence of SFN on ROS and ROS-related pathways and appraises a possible role of SFN in bladder cancer treatment.

Intersection between Redox Homeostasis and Autophagy: Valuable Insights into Neurodegeneration

Autophagy, a main degradation pathway for maintaining cellular homeostasis, and redox homeostasis have recently been considered to play protective roles in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. Increased levels of reactive oxygen species (ROS) in neurons can induce mitochondrial damage and protein aggregation, thereby resulting in neurodegeneration. Oxidative stress is one of the major activation signals for the induction of autophagy. Upon activation, autophagy can remove ROS, damaged mitochondria, and aggregated proteins from the cells. Thus, autophagy can be an effective strategy to maintain redox homeostasis in the brain. However, the interaction between redox homeostasis and autophagy is not clearly elucidated. In this review, we discuss recent studies on the relationship between redox homeostasis and autophagy associated with neurodegenerative diseases and propose that autophagy induction through pharmacological intervention or genetic activation might be a promising strategy to treat these disorders.

p62 functions as a signal hub in metal carcinogenesis

A number of metals are toxic and carcinogenic to humans. Reactive oxygen species (ROS) play an important role in metal carcinogenesis. Oxidative stress acts as the converging point among various stressors with ROS being the main intracellular signal transducer. In metal-transformed cells, persistent expression of p62 and erythroid 2-related factor 2 (Nrf2) result in apoptosis resistance, angiogenesis, inflammatory microenvironment, and metabolic reprogramming, contributing to overall mechanism of metal carcinogenesis. Autophagy, a conserved intracellular process, maintains cellular homeostasis by facilitating the turnover of protein aggregates, cellular debris, and damaged organelles. In addition to being a substrate of autophagy, p62 is also a crucial molecule in a myriad of cellular functions and in molecular events, which include oxidative stress, inflammation, apoptosis, cell proliferation, metabolic reprogramming, that modulate cell survival and tumor growth. The multiple functions of p62 are appreciated by its ability to interact with several key components involved in various oncogenic pathways. This review summarizes the current knowledge and progress in studies of p62 and metal carcinogenesis with emphasis on oncogenic pathways related to oxidative stress, inflammation, apoptosis, and metabolic reprogramming.

Re-Evaluating the Oxidative Phenotype: Can Endurance Exercise Save the Western World?

Mitochondria are popularly called the "powerhouses" of the cell. They promote energy metabolism through the tricarboxylic acid (TCA) cycle and oxidative phosphorylation, which in contrast to cytosolic glycolysis are oxygen-dependent and significantly more substrate efficient. That is, mitochondrial metabolism provides substantially more cellular energy currency (ATP) per macronutrient metabolised. Enhancement of mitochondrial density and metabolism are associated with endurance training, which allows for the attainment of high relative VO2 max values. However, the sedentary lifestyle and diet currently predominant in the Western world lead to mitochondrial dysfunction. Underdeveloped mitochondrial metabolism leads to nutrient-induced reducing pressure caused by energy surplus, as reduced nicotinamide adenine dinucleotide (NADH)-mediated high electron flow at rest leads to "electron leak" and a chronic generation of superoxide radicals (O2-). Chronic overload of these reactive oxygen species (ROS) damages cell components such as DNA, cell membranes, and proteins. Counterintuitively, transiently generated ROS during exercise contributes to adaptive reduction-oxidation (REDOX) signalling through the process of cellular hormesis or "oxidative eustress" defined by Helmut Sies. However, the unaccustomed, chronic oxidative stress is central to the leading causes of mortality in the 21st century-metabolic syndrome and the associated cardiovascular comorbidities. The endurance exercise training that improves mitochondrial capacity and the protective antioxidant cellular system emerges as a universal intervention for mitochondrial dysfunction and resultant comorbidities. Furthermore, exercise might also be a solution to prevent ageing-related degenerative diseases, which are caused by impaired mitochondrial recycling. This review aims to break down the metabolic components of exercise and how they translate to athletic versus metabolically diseased phenotypes. We outline a reciprocal relationship between oxidative metabolism and inflammation, as well as hypoxia. We highlight the importance of oxidative stress for metabolic and antioxidant adaptation. We discuss the relevance of lactate as an indicator of critical exercise intensity, and inferring from its relationship with hypoxia, we suggest the most appropriate mode of exercise for the case of a lost oxidative identity in metabolically inflexible patients. Finally, we propose a reciprocal signalling model that establishes a healthy balance between the glycolytic/proliferative and oxidative/prolonged-ageing phenotypes. This model is malleable to adaptation with oxidative stress in exercise but is also susceptible to maladaptation associated with chronic oxidative stress in disease. Furthermore, mutations of components involved in the transcriptional regulatory mechanisms of mitochondrial metabolism may lead to the development of a cancerous phenotype, which progressively presents as one of the main causes of death, alongside the metabolic syndrome.

Mitochondrial Dynamics, ROS, and Cell Signaling: A Blended Overview

Mitochondria are key intracellular organelles involved not only in the metabolic state of the cell, but also in several cellular functions, such as proliferation, Calcium signaling, and lipid trafficking. Indeed, these organelles are characterized by continuous events of fission and fusion which contribute to the dynamic plasticity of their network, also strongly influenced by mitochondrial contacts with other subcellular organelles. Nevertheless, mitochondria release a major amount of reactive oxygen species (ROS) inside eukaryotic cells, which are reported to mediate a plethora of both physiological and pathological cellular functions, such as growth and proliferation, regulation of autophagy, apoptosis, and metastasis. Therefore, targeting mitochondrial ROS could be a promising strategy to overcome and hinder the development of diseases such as cancer, where malignant cells, possessing a higher amount of ROS with respect to healthy ones, could be specifically targeted by therapeutic treatments. In this review, we collected the ultimate findings on the blended interplay among mitochondrial shaping, mitochondrial ROS, and several signaling pathways, in order to contribute to the dissection of intracellular molecular mechanisms involved in the pathophysiology of eukaryotic cells, possibly improving future therapeutic approaches.