Interplay between VEGF and Nrf2 regulates angiogenesis due to intracranial venous hypertension

Role of nuclear factor erythroid 2-related factor 2 in negative pressure wound therapy for diabetic foot ulcers

BACKGROUND

Negative pressure wound therapy (NPWT) is a potential treatment for diabetic foot ulcers (DFUs), although the mechanisms underlying its effectiveness remain unclear. This study posits that NPWT may improve wound healing by promoting angiogenesis and activating the nuclear factor erythroid 2-related factor 2 (Nrf2)/Kelch-like epichlorohydrin-associated protein 1 (Keap1) signaling pathway, which is crucial for the body’s defense against oxidative stress. The hypothesis indicates that enhancing antioxidant defenses through NPWT may positively affect the healing process. There are still limited data on the roles of Nrf2, its downstream signaling molecules, and angiogenesis markers in patients undergoing NPWT.

AIM

To study the mechanism of NPWT in DFUs.

METHODS

This study included a total of 40 hospitalized patients with DFUs from Xuzhou Central Hospital, who were divided into Control group (n = 21) and NPWT group (n = 19). The levels of Nrf2 and Keap1 were analyzed in the granulation tissue 7 days after treatment. The wound condition, erythrocyte sedimentation rate (ESR), procalcitonin (PCT), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (b-FGF), cluster of differentiation 31 (CD31), and levels of oxidative stress [malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and total antioxidant capacity (T-AOC)] were analyzed before and 7 days after treatment by the Mann-Whitney U test.

RESULTS

The NPWT group demonstrated significant improvements in wound healing compared to the control group after 7 days of treatment. The levels of ESR, PCT, IL-6, and TNF-α were significantly reduced in the NPWT group compared to the control group (P < 0.05), while the levels of CD31, VEGF, and b-FGF showed significant increases (P < 0.05). The NPWT group exhibited notable elevations in the levels of Nrf2 and its downstream targets (SOD, CAT, and T-AOC), accompanied by decreases in the levels of Keap1 and MDA (P < 0.05).

CONCLUSION

NPWT may contribute to the healing of DFUs by potentially reducing levels of oxidative stress. Its effects could possibly be enhanced through the action of Nrf2.

Butylphthalide protects cerebral infarction in a rat model by regulating netrin-1/deleted in colorectal cancer/vascular endothelial growth factor axis

Acute cerebral infarction (CI) is characterized by acute onset, high disability rate, and high morbidity rate, which seriously threatens the health and safety of people and places a heavy burden on individuals and the country. This study aimed to explore the effects of butylphthalide on nerve cell ferroptosis in CI rats and its underlying mechanisms. Middle cerebral artery occlusion (MCAO) rat model was used to study the effect of butylphthalide on acute CI in vivo and oxygen glucose deprivation (OGD) model was used to study the effect of butylphthalide on acute CI in vitro. Our findings demonstrated that butylphthalide markedly reduced oxidative damage and ferroptosis in the brains of MCAO rats. Furthermore, we found that butylphthalide upregulated the netrin-1/deleted in colorectal cancer (DCC)/vascular endothelial growth factor (VEGF) signaling axis, which regulates NF-E2-related factor-2 (NRF2) expression and contributes to ferroptosis in the MCAO rat model and OGD-treated HT22 cells. Collectively, our findings indicate that butylphthalide inhibits oxidative stress-mediated ferroptosis in the MCAO rat model and OGD-treated HT22 cells by modulating the netrin-1/DCC/VEGF/NRF2 axis. In conclusion, our results reveal a novel mechanism for the protection of acute CIs by butylphthalide.

Overview of Nrf2 as a target in ovary and ovarian dysfunctions focusing on its antioxidant properties

Female infertility is a common issue caused by various factors, such as hormonal imbalances, age-related decline in oocyte quality, and lifestyle choices. Ovarian dysfunction is a prevalent cause, impacting fertility by damaging cells and impairing functions. Oxidative stress (OS) is a condition resulting from an imbalance between natural antioxidants and the generation of oxidants. This phenomenon acts as a double-edged sword, playing a crucial role as a signaling mechanism in both physiological and pathological processes related to the female reproductive system. OS is linked to ovarian dysfunction, leading to cell damage and reduced fertility. Nrf2 is a key regulator in oxidative homeostasis, helping to defend against OS and improve ovarian function in women of reproductive age. Therefore, this review aims to highlight the role of Nrf2 in the female reproductive system, focusing on its antioxidant properties.

Tumor-associated macrophages in bladder cancer: roles and targeted therapeutic strategies

Bladder cancer (BC) is the ninth most common and "expensive" cancer in the world. Despite the availability of various treatment modalities such as chemotherapy, immunotherapy and surgery, the overall survival rate of patients with advanced bladder cancer remains low. As one of the most abundant infiltrating immune cells in bladder cancer, tumor-associated macrophages (TAMs) play an important role in the development of BC and in the standard regimen of intravesical BCG therapy. Targeting TAMs have achieved excellent results in clinical trials for a variety of other cancers, but few studies have been conducted for bladder cancer. Further exploration is still needed to develop TAM-related therapeutic strategies for BC treatment, which are expected to improve the therapeutic efficacy and life quality of patients. This review summarizes the relationship between TAMs in bladder cancer and disease staging, evolution, patient prognosis, and treatment outcome. Several potential TAM targets in BC are also pointed, which may help to inhibit tumor-promoting TAMs and provide new therapeutic approaches for advanced BC.

Nrf2/ASPM axis regulated vasculogenic mimicry formation in hepatocellular carcinoma under hypoxia

BACKGROUND

Hypoxic microenvironment is a common feature of most solid tumors including hepatocellular carcinoma (HCC). Vasculogenic mimicry (VM) formation by tumor cells could provide blood supply to tumor cells under hypoxia. NFE2 like basic leucine zipper (bZIP) transcription factor 2 (Nrf2), a regulator of cellular homeostasis, may promote tumor progression in the hypoxic conditions. However, the role and regulatory mechanisms of Nrf2 in HCC are not fully elucidated.

METHODS

Nrf2 and assembly factor for spindle microtubules (ASPM) expression modulations were conducted by lentiviral transfections. Western blot, immunofluorescence, ChIP-qPCR, dual-luciferase reporter gene assay, flow cytometry, RNA sequencing, multiple bioinformatics databases analysis, cell function assays in vitro, mouse model in vivo and human HCC tissues were employed to assess the effect of Nrf2/ASPM axis on HCC progression under hypoxia.

RESULTS

Nrf2 and ASPM expression facilitated epithelial-mesenchymal transition (EMT), cancer stem cells (CSCs) feature, and VM formation of HCC cells under hypoxia. Furthermore, Nrf2-regulated ASPM expression, via binding directly to the promoter region of ASPM and transcriptionally promoting ASPM expression. ASPM re-expression in Nrf2 knockdown cells or ASPM knockdown in Nrf2 overexpression cells reversed the cellular function caused by Nrf2. Meantime, retinol metabolism pathway was disrupted following abnormal ASPM expression. Nrf2/ASPM axis in murine models accelerated tumor growth and VM, corroborating in vitro findings. All-trans retinoic acid treatment reversed stemness and VM of HCC cells in vitro and in vivo. Clinically, Nrf2 and ASPM expressions were related to poor prognosis of HCC patients.

CONCLUSIONS

Nrf2 drives EMT, CSCs characteristics and VM in HCC under hypoxia through the modulation of ASPM. Retinol metabolism pathway was dysregulated in HCC cells with ASPM overexpression. Nrf2/ASPM axis and related pathway provided potential therapeutic target for HCC.

Near-Infrared Stimuli-Responsive Hydrogel Promotes Cell Migration for Accelerated Diabetic Wound Healing

Diabetic wound healing including diabetic foot ulcers is a major clinical challenge, which could bring an increased level of mortality and morbidity. However, conventional wound dressings exhibit limited healing efficacy due to their lack of active modulation for the healing process. Here, a near-infrared (NIR) stimuli-responsive composite hydrogel dressing with the synergistic effect of both mechanical contraction and epithelial-mesenchymal transition (EMT) was developed to facilitate cell migration and vascularization for diabetic wound healing. In the methacrylated gelatin-based composite hydrogel, N-isopropylacrylamide and polydopamine nanoparticles were incorporated to endow the composite hydrogel with thermosensitive and photothermal properties. Linagliptin (LIN) was loaded into the composite hydrogel, and the drug release rate could be controlled by NIR laser irradiation. NIR-triggered on-demand active contraction of wound area and LIN release for biological stimulation were potentially realized in this responsive system due to the thermally induced sol-gel transition of the composite hydrogel. The release of loaded LIN could effectively promote cell migration by activating EMT and enhancing angiogenesis. In the full-thickness skin defect model, the LIN-loaded composite hydrogel with NIR laser irradiation had the highest wound closure rate as compared with the pure hydrogel and LIN-loaded hydrogel groups. Therefore, this composite hydrogel can serve as an excellent platform for promoting wound healing and will find more practical value in clinical treatment.

Glioprotective Effects of Sulforaphane in Hypothalamus: Focus on Aging Brain

Sulforaphane is a natural compound with neuroprotective activity, but its effects on hypothalamus remain unknown. In line with this, astrocytes are critical cells to maintain brain homeostasis, and hypothalamic astrocytes are fundamental for sensing and responding to environmental changes involved in a variety of homeostatic functions. Changes in brain functionality, particularly associated with hypothalamic astrocytes, can contribute to age-related neurochemical alterations and, consequently, neurodegenerative diseases. Thus, here, we investigated the glioprotective effects of sulforaphane on hypothalamic astrocyte cultures and hypothalamic cell suspension obtained from aged Wistar rats (24 months old). Sulforaphane showed anti-inflammatory and antioxidant properties, as well as modulated the mRNA expression of astroglial markers, such as aldehyde dehydrogenase 1 family member L1, aquaporin 4, and vascular endothelial growth factor. In addition, it increased the expression and extracellular levels of trophic factors, such as glia-derived neurotrophic factor and nerve growth factor, as well as the release of brain-derived neurotrophic factor and the mRNA of TrkA, which is a receptor associated with trophic factors. Sulforaphane also modulated the expression of classical pathways associated with glioprotection, including nuclear factor erythroid-derived 2-like 2, heme oxygenase-1, nuclear factor kappa B p65 subunit, and AMP-activated protein kinase. Finally, a cell suspension with neurons and glial cells was used to confirm the predominant effect of sulforaphane in glial cells. In summary, this study indicated the anti-aging and glioprotective activities of sulforaphane in aged astrocytes.

Brain Arteriovenous Malformation Hemorrhage and Pituitary Adenoma in a COVID-19-Positive Patient

Brain arteriovenous malformations (AVMs) are usually asymptomatic. They can cause intense pain or bleeding or lead to other serious medical problems. We present a rare case of a woman who presented with a severe headache and was brought to the emergency service for an intracerebral hemorrhage due to a ruptured AVM. During the surgery, a sellar mass was identified that was also resected. AVM showed vasculitis, endarteritis, endothelial damage, leukocyte plug, and damage to the vessel wall with fragmentation of the collagen and actin filaments. The sellar mass showed a non-functioning pituitary adenoma with hemorrhagic foci and necrosis as well as a proteinaceous vs. lipid material deposition with minimal vascular changes such as endothelial hyperplasia with minimal vasculitis and hyperplasia of reticular stellate cells, with positive glial fibrillary acidic protein (GFAP), which expressed low expression of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), IL6, IL10, IL17, tumor necrosis factor-alpha (TNFa), HIF1a, factor VIII (FVIII), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and VEGF receptor 2 (VEGFR2). The patient's polymerase chain reaction COVID-19 test was positive, and she died three days after the surgery procedure. In our knowledge of COVID-19 brain lesions and in the literature review, this was a rare case of a double pathology associated with COVID-19 infection characterized by rupture of the AVM with hemorrhages and brain infarcts associated with endarteritis, vessel wall injuries, and pituitary apoplexy.

Functional Mechanisms of Dietary Crocin Protection in Cardiovascular Models under Oxidative Stress

It was previously reported that crocin, a water-soluble carotenoid isolated from the Crocus sativus L. (saffron), has protective effects on cardiac cells and may neutralize and even prevent the formation of excess number of free radicals; however, functional mechanisms of crocin activity have been poorly understood. In the present research, we aimed to study the functional mechanism of crocin in the heart exposed to oxidative stress. Accordingly, oxidative stress was modeled in vitro on human umbilical vein endothelial cells (HUVECs) and in vivo in mice using cellular stressors. The beneficial effects of crocin were investigated at cellular and molecular levels in HUVECs and mice hearts. Results indicated that oral administration of crocin could have protective effects on HUVECs. In addition, it protects cardiac cells and significantly inhibits inflammation via modulating molecular signaling pathways TLR4/PTEN/AKT/mTOR/NF-κB and microRNA (miR-21). Here we show that crocin not only acts as a direct free radical scavenger but also modifies the gene expression profiles of HUVECs and protects mice hearts with anti-inflammatory action under oxidative stress.

A recombinant plasmid encoding human hepatocyte growth factor promotes healing of combined radiation-trauma skin injury involved in regulating Nrf2 pathway in mice

Combined radiation-trauma skin injury represents a severe and intractable condition that urgently requires effective therapeutic interventions. In this context, hepatocyte growth factor (HGF), a multifunctional growth factor with regulating cell survival, angiogenesis, anti-inflammation and antioxidation, may be valuable for the treatment of combined radiation-trauma injury. This study investigated the protective effects of a recombinant plasmid encoding human HGF (pHGF) on irradiated human immortalized keratinocytes (HaCaT) cells in vitro, and its capability to promote the healing of combined radiation-trauma injuries in mice. The pHGF radioprotection on irradiated HaCaT cells in vitro was assessed by cell viability, the expression of Nrf2, Bcl-2 and Bax, as well as the secretion of inflammatory cytokines. In vivo therapeutic treatment, the irradiated mice with full-thickness skin wounds received pHGF local injection. The injuries were appraised based on relative wound area, pathology, immunohistochemical detection, terminal deoxynucleotidyl transferase dUTP nick end labelling assay and cytokine content. The transfection of pHGF increased the cell viability and Nrf2 expression in irradiated HaCaT cells. pHGF also significantly upregulated Bcl-2 expression, decreased the Bax/Bcl-2 ratio and inhibited the expression of interleukin-1β and tumor necrosis factor-α in irradiated cells. Local pHGF injection in vivo caused high HGF protein expression and noticeable accelerated healing of combined radiation-trauma injury. Moreover, pHGF administration upregulated Nrf2, vascular endothelial growth factor, Bcl-2 expression, downregulated Bax expression and mitigated inflammatory response. In conclusion, the protective effect of pHGF may be related to inhibiting apoptosis and inflammation involving by upregulating Nrf2. Local pHGF injection distinctly promoted the healing of combined radiation-trauma injury and demonstrates potential as a gene therapy intervention for combined radiation-trauma injury in clinic.

Translational application of human keratinocyte-fibroblast cell sheets for accelerated wound healing in a clinically relevant type 2 diabetic rat model

BACKGROUND AIMS

Despite advancements in wound care, wound healing remains a challenge, especially in individuals with type 2 diabetes. Cell sheet technology has emerged as an efficient and promising therapy for tissue regeneration and wound repair. Among these, bilayered human keratinocyte-fibroblast cell sheets constructed using temperature-responsive culture surfaces have been shown to mimic a normal tissue-like structure and secrete essential cytokines and growth factors that regulate the wound healing process.

METHODS

This study aimed to evaluate the safety and therapeutic potential of human skin cell sheets to treat full-thickness skin defects in a rat model of type 2 diabetes.

RESULTS

Our findings demonstrate that diabetic wounds transplanted with bilayered cell sheets resulted in accelerated re-epithelialization, increased angiogenesis, enhanced macrophage polarization and regeneration of tissue that closely resembled healthy skin. In contrast, the control group that did not receive cell sheet transplantation presented characteristic symptoms of impaired and delayed wound healing associated with type 2 diabetes.

CONCLUSIONS

The secretory cytokines and the upregulation of Nrf2 expression in response to cell sheet transplantation are believed to have played a key role in the improved wound healing observed in diabetic rats. Our study suggests that human keratinocyte-fibroblast cell sheets hold great potential as a therapeutic alternative for diabetic ulcers.

Hypoxia, oxidative stress, and the interplay of HIFs and NRF2 signaling in cancer

Oxygen is crucial for life and acts as the final electron acceptor in mitochondrial energy production. Cells adapt to varying oxygen levels through intricate response systems. Hypoxia-inducible factors (HIFs), including HIF-1α and HIF-2α, orchestrate the cellular hypoxic response, activating genes to increase the oxygen supply and reduce expenditure. Under conditions of excess oxygen and resulting oxidative stress, nuclear factor erythroid 2-related factor 2 (NRF2) activates hundreds of genes for oxidant removal and adaptive cell survival. Hypoxia and oxidative stress are core hallmarks of solid tumors and activated HIFs and NRF2 play pivotal roles in tumor growth and progression. The complex interplay between hypoxia and oxidative stress within the tumor microenvironment adds another layer of intricacy to the HIF and NRF2 signaling systems. This review aimed to elucidate the dynamic changes and functions of the HIF and NRF2 signaling pathways in response to conditions of hypoxia and oxidative stress, emphasizing their implications within the tumor milieu. Additionally, this review explored the elaborate interplay between HIFs and NRF2, providing insights into the significance of these interactions for the development of novel cancer treatment strategies.

Arsenic Trioxide Suppresses Angiogenesis in Non-small Cell Lung Cancer via the Nrf2-IL-33 Signaling Pathway

BACKGROUND

Non-Small Cell Lung Cancer (NSCLC) ranks as a leading cause of cancer-related mortality, necessitating the urgent search for cost-effective and efficient anti-NSCLC drugs. Our preliminary research has demonstrated that arsenic trioxide (ATO) significantly inhibits NSCLC angiogenesis, exerting anti-tumor effects. In conjunction with existing literature reports, the Nrf2-IL-33 pathway is emerging as a novel mechanism in NSCLC angiogenesis.

OBJECTIVE

This study aimed to elucidate whether ATO can inhibit NSCLC angiogenesis through the Nrf2-IL-33 pathway.

METHODS

Immunohistochemistry was employed to assess the expression of Nrf2, IL-33, and CD31 in tumor tissues from patients with NSCLC. DETA-NONOate was used as a nitric oxide (NO) donor to mimic high levels of NO in the tumor microenvironment. Western blot, quantitative real-time PCR, and enzyme-linked immunosorbent assay were utilized to evaluate the expression of Nrf2 and IL-33 in the NCI-H1299 cell line. Subcutaneous xenograft models were established in nude mice by implanting NCI-H1299 cells to assess the anti-tumor efficacy of ATO.

RESULTS

High expression levels of Nrf2 and IL-33 were observed in tumor samples from patients with NSCLC, and Nrf2 expression positively correlated with microvascular density in NSCLC. In vitro, NO (released from 1mM DETA-NONOate) promoted activation of the Nrf2-IL-33 signaling pathway in NCI-H1299 cells, which was reversed by ATO. Additionally, both Nrf2 deficiency and ATO treatment significantly attenuated NOinduced IL-33 expression. In vivo, both ATO and the Nrf2 inhibitor ML385 demonstrated significant inhibitory effects on angiogenesis tumor growth.

CONCLUSION

Nrf2-IL-33 signaling is usually activated in NSCLC and positively correlates with tumor angiogenesis. ATO effectively disrupts the activation of the Nrf2-IL-33 pathway in NSCLC and thus inhibits angiogenesis, suggesting its potential as an anti-angiogenic agent for use in the treatment of NSCLC.

The Oxygen-Ozone Adjunct Medical Treatment According to the Protocols from the Italian Scientific Society of Oxygen-Ozone Therapy: How Ozone Applications in the Blood Can Influence Clinical Therapy Success via the Modulation of Cell Biology and Immunity

BACKGROUND

Ozone is an allotrope of oxygen whose use in medicine has rapidly grown in recent years. Ozonated blood allows for the use of ozone in a safe modality, as plasma and blood cells are endowed with an antioxidant system able to quench ozone's pro-oxidant property and to elicit the Nrf2/Kwap1/ARE pathway.

METHODS

We present two clinical studies, a case-series (six patients) observational study adopting ozone as a major autohemotherapy and topical ozone to address infected post-surgical wounds with multi-drug resistant bacteria and an observational study (250 patients) using ozonated blood for treating knee osteoarthritis.

RESULTS

Ozonated blood via major autohemotherapy reduced the extent of infections in wounds, reduced the inflammatory biomarkers by more than 75% and improved patients' QoL, whereas ozonated blood via minor autohemotherapy improved significantly (p < 0.001) WOMAC and Lequesne's parameters in knee osteoarthritis.

CONCLUSIONS

The models described, i.e., ozone autohemotherapy in wound antimicrobial treatment and ozonated blood in knee osteoarthrosis, following our protocols, share the outstanding ability of ozone to modulate the innate immune response and address bacterial clearance as well as inflammation and pain.

Fetal head-down posture may explain the rapid brain evolution in humans and other primates: An interpretative review

Evolutionary cerebrovascular consequences of upside-down postural verticality of the anthropoid fetus have been largely overlooked in the literature. This working hypothesis-based report provides a literature interpretation from an aspect that the rapid evolution of the human brain has been promoted by fetal head-down position due to maternal upright and semi-upright posture. Habitual vertical torso posture is a feature not only of humans, but also of monkeys and non-human apes that spend considerable time in a sitting position. Consequently, the head-down position of the fetus may have caused physiological craniovascular hypertension that stimulated expansion of the intracranial vessels and acted as an epigenetic physiological stress, which enhanced neurogenesis and eventually, along with other selective pressures, led to the progressive growth of the anthropoid brain and its organization. This article collaterally opens a new insight into the conundrum of high cephalopelvic proportions (i.e., the tight fit between the pelvic birth canal and fetal head) in phylogenetically distant lineages of monkeys, lesser apes, and humans. Low cephalopelvic proportions in non-human great apes could be accounted for by their energetically efficient horizontal nest-sleeping and consequently by their larger body mass compared to monkeys and lesser apes that sleep upright. One can further hypothesize that brain size varies in anthropoids according to the degree of exposure of the fetus to postural verticality. The supporting evidence for this postulation includes a finding that in fossil hominins cerebral blood flow rate increased faster than brain volume. This testable hypothesis opens a perspective for research on fetal postural cerebral hemodynamics.

Fucoidan promotes angiogenesis and accelerates wound healing through AKT/Nrf2/HIF-1α signalling pathway

After skin injury, wound repair involves a complex process in which angiogenesis plays a crucial role. Previous research has indicated that fucoidan may aid in wound healing; we therefore hypothesised that fucoidan may speed up the process by promoting angiogenesis. In this study, we investigated the potential molecular mechanism underlying fucoidan's ability to accelerate wound healing by promoting angiogenesis. Using a full-cut wound model, we observed that fucoidan significantly intensified wound closure and promoted granulation formation and collagen deposition. Immunofluorescence staining revealed that fucoidan also promoted wound angiogenesis, specifically by accelerating the migration of new blood vessels to the middle area of the wound. Furthermore, fucoidan demonstrated the ability to enhance the proliferation of human umbilical vein endothelial cells (HUVECs) damaged by hydrogen peroxide (H2 O2 ) and to improve the formation of endothelial tubes. Mechanistic studies revealed that fucoidan upregulated the protein levels of the AKT/Nrf2/HIF-1α signalling pathway, which plays a crucial role in angiogenesis. This was further confirmed using the inhibitor LY294002, which reversed the promotion of endothelial tube formation by fucoidan. Overall, our findings suggest that fucoidan can promote angiogenesis via the AKT/Nrf2/HIF-1α signalling pathway and accelerate wound healing.

MicroRNA-27b Impairs Nrf2-Mediated Angiogenesis in the Progression of Diabetic Foot Ulcer

Nuclear factor erythroid-2-related factor 2 (Nrf2) is a stress-activated transcription factor regulating antioxidant genes, and a deficiency thereof, slowing lymphangiogenesis, has been reported in diabetic foot ulcer (DFU). The mode of Nrf2 regulation in DFU has been less explored. Emerging studies on miRNA-mediated target regulation show miRNA to be the leading player in the pathogenesis of the disease. In the present study, we demonstrated the role of miR-27b in regulating Nrf2-mediated angiogenesis in DFU. A lower expression of mRNA targets, such as Nrf2, HO-1, SDF-1α, and VEGF, was observed in tissue biopsied from chronic DFU subjects, which was in line with miR-27b, signifying a positive correlation with Nrf2. Similarly, we found significantly reduced expression of miR-27b and target mRNAs Nrf2, HO-1, SDF-1α, and VEGF in endothelial cells under a hyperglycemic microenvironment (HGM). To confirm the association of miR-27b on regulating Nrf2-mediated angiogenesis, we inhibited its expression through RNA interference-mediated knockdown and observed disturbances in angiogenic signaling with reduced endothelial cell migration. In addition, to explore the role of miR-27b and angiogenesis in the activation of Nrf2, we pretreated the endothelial cells with two well-known pharmacological compounds-pterostilbene and resveratrol. We observed that activation of Nrf2 through these compounds ameliorates impaired angiogenesis on HGM-induced endothelial cells. This study suggests a positive role of miR-27b in regulating Nrf2, which seems to be decreased in DFU and improves on treatment with pterostilbene and resveratrol.

M2 tumor-associated macrophages resist to oxidative stress through heme oxygenase-1 in the colorectal cancer tumor microenvironment

M2 tumor-associated macrophages (M2-TAMs) promote cancer cell proliferation and metastasis in the TME. Our study aimed to elucidate the mechanism of increased frequency of M2-TAMs infiltration in the colorectal cancer (CRC)-TME, focusing on the resistance to oxidative stress through nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. In this study, we evaluated the correlation between M2-TAM signature and mRNA expression of antioxidant related genes using public datasets, and the expression level of antioxidants in M2-TAMs by flow cytometry and the prevalence of M2-TAMs expressing antioxidants by immunofluorescence staining using surgically resected specimens of CRC (n = 34). Moreover, we generated M0 and M2 macrophages from peripheral blood monocytes and evaluated their resistance to oxidative stress using the in vitro viability assay. Analysis of GSE33113, GSE39582, and The Cancer Genome Atlas (TCGA) datasets indicated that mRNA expression of HMOX1 (heme oxygenase-1 (HO-1)) was significantly positively correlated with M2-TAM signature (r = 0.5283, r = 0.5826, r = 0.5833, respectively). The expression level of both Nrf2 and HO-1 significantly increased in M2-TAMs compared to M1- and M1/M2-TAMs in the tumor margin, and the number of Nrf2+ or HO-1+M2-TAMs in the tumor stroma significantly increased more than those in the normal mucosa stroma. Finally, generated M2 macrophages expressing HO-1 significantly resisted to oxidative stress induced by H2O2 in comparison with generated M0 macrophages. Taken together, our results suggested that an increased frequency of M2-TAMs infiltration in the CRC-TME is related to Nrf2-HO-1 axis mediated resistance to oxidative stress.

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.

Physiological and Pathological Remodeling of Cerebral Microvessels

There is growing evidence that the remodeling of cerebral microvessels plays an important role in plastic changes in the brain associated with development, experience, learning, and memory consolidation. At the same time, abnormal neoangiogenesis, and deregulated regulation of microvascular regression, or pruning, could contribute to the pathogenesis of neurodevelopmental diseases, stroke, and neurodegeneration. Aberrant remodeling of microvesselsis associated with blood-brain barrier breakdown, development of neuroinflammation, inadequate microcirculation in active brain regions, and leads to the dysfunction of the neurovascular unit and progressive neurological deficits. In this review, we summarize current data on the mechanisms of blood vessel regression and pruning in brain plasticity and in Alzheimer's-type neurodegeneration. We discuss some novel approaches to modulating cerebral remodeling and preventing degeneration-coupled aberrant microvascular activity in chronic neurodegeneration.

Exploring the role of Nrf2 signaling in glioblastoma multiforme

Glioblastoma multiforme (GBM) is one of the most aggressive glial cell tumors in adults. Although current treatment options for GBM offer some therapeutic benefit, median survival remains poor and does not generally exceed 14 months. Several genes, such as isocitrate dehydrogenase (IDH) enzyme and O6-methylguanine-DNA methyltransferase (MGMT), have been implicated in pathogenesis of the disease. Treatment is often adapted based on the presence of IDH mutations and MGMT promoter methylation status. Recent GBM cell line studies have associated Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2) expression with high-grade tumors. Increased Nrf2 expression is often found in tumors with IDH-1 mutations. Nrf2 is an important transcription factor with anti-apoptotic, antioxidative, anti-inflammatory, and proliferative properties due to its complex interactions with multiple regulatory pathways. In addition, evidence suggests that Nrf2 promotes  GBM cell survival in hypoxic environment,by up-regulating hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). Downregulation of Nrf2 has been shown to improve GBM sensitivity to chemotherapy drugs such as Temozolomide. Thus, Nrf2 could be a key regulator of GBM pathways and potential therapeutic target.  Further research efforts exploring an interplay between Nrf2 and major molecular signaling mechanisms could offer novel GBM drug candidates with a potential to significantly improve patients prognosis.

Thymoquinone has a synergistic effect with PHD inhibitors to ameliorate ischemic brain damage in mice

BACKGROUND

A blockage in a blood vessel can cause reduced blood flow to the brain, which eventually leads to the death of surrounding tissue. Several studies have attempted to develop an effective intervention to reverse this process and improve the health status of affected individuals. Due to its indirect effect on cellular functions and metabolism, the hypoxia-inducible factor (HIF-1α) protein has been proposed as a promising transcription factor in the treatment of stroke.

PURPOSE

The current study aims to explore the relation between HIF-1 α and thymoquinone (TQ) in the attenuation of ischemic brain damage and the possible mechanism of this relation to reduce cell death.

METHODS

For this purpose, dimethyloxallyl glycine (DMOG), 8 mg/kg, Acriflavine (ACF), 1.5 mg/kg, and both combined with TQ (5 mg/kg) were assessed. Male C57 mice were used to establish an ischemic stroke model by using endothelin-1 (ET-1) (400 pmole/μl) intra- cranial injection. The ultrastructure alterations of neuronal soma, axons, and mitochondria after stroke and treatment were well addressed. Besides, the expression levels of VEGF, HIF-1α, Nrf2, and HO-1 were evaluated. Meanwhile, apoptosis and autophagy-related proteins were also investigated.

RESULTS

Treatment of ischemic stroke by TQ can activate the HIF-1α pathway and its downstream genes such as VEGF, TrkB, and PI3K, which in turn enhance angiogenesis and neurogenesis. Our study revealed that TQ has the same effect as DMOG to activate HIF-1 α and can improve motor dysfunction after ischemic stroke. Further, we demonstrated that both TQ and DMOG effectively attenuate the organelle's damage following ischemic stroke, which was confirmed by the cryogenic transmission electron microscope. The synergistic effect of TQ and DMOG may lead to a chemo-modulation action in the autophagy process after stroke onset and this result is validated by the western blot and rt-qPCR techniques.

CONCLUSION

Our finding revealed the potential role of TQ as a HIF-1 α activator to reduce cell death, modulate autophagy and decrease the infarct volume after ischemic stroke onset. The neuroprotective effect of TQ is achieved by decreasing the inflammation and increasing angiogenesis as well as neurogenesis via induction of the HIF-1α-VEGF/Nrf2-HO-1-TrkB-PI3K pathway.

The molecular biology and therapeutic potential of Nrf2 in leukemia

NF-E2-related factor 2 (Nrf2) transcription factor has contradictory roles in cancer, which can act as a tumor suppressor or a proto-oncogene in different cell conditions (depending on the cell type and the conditions of the cell environment). Nrf2 pathway regulates several cellular processes, including signaling, energy metabolism, autophagy, inflammation, redox homeostasis, and antioxidant regulation. As a result, it plays a crucial role in cell survival. Conversely, Nrf2 protects cancerous cells from apoptosis and increases proliferation, angiogenesis, and metastasis. It promotes resistance to chemotherapy and radiotherapy in various solid tumors and hematological malignancies, so we want to elucidate the role of Nrf2 in cancer and the positive point of its targeting. Also, in the past few years, many studies have shown that Nrf2 protects cancer cells, especially leukemic cells, from the effects of chemotherapeutic drugs. The present paper summarizes these studies to scrutinize whether targeting Nrf2 combined with chemotherapy would be a therapeutic approach for leukemia treatment. Also, we discussed how Nrf2 and NF-κB work together to control the cellular redox pathway. The role of these two factors in inflammation (antagonistic) and leukemia (synergistic) is also summarized.

Human organ rejuvenation by VEGF-A: Lessons from the skin

Transplanting aged human skin onto young SCID/beige mice morphologically rejuvenates the xenotransplants. This is accompanied by angiogenesis, epidermal repigmentation, and substantial improvements in key aging-associated biomarkers, including ß-galactosidase, p16^ink4a, SIRT1, PGC1α, collagen 17A, and MMP1. Angiogenesis- and hypoxia-related pathways, namely, vascular endothelial growth factor A (VEGF-A) and HIF1A, are most up-regulated in rejuvenated human skin. This rejuvenation cascade, which can be prevented by VEGF-A-neutralizing antibodies, appears to be initiated by murine VEGF-A, which then up-regulates VEGF-A expression/secretion within aged human skin. While intradermally injected VEGF-loaded nanoparticles suffice to induce a molecular rejuvenation signature in aged human skin on old mice, VEGF-A treatment improves key aging parameters also in isolated, organ-cultured aged human skin, i.e., in the absence of functional skin vasculature, neural, or murine host inputs. This identifies VEGF-A as the first pharmacologically pliable master pathway for human organ rejuvenation in vivo and demonstrates the potential of our humanized mouse model for clinically relevant aging research.

Hypoxia-driven metabolic heterogeneity and immune evasive behaviour of gastrointestinal cancers: Elements of a recipe for disaster

Gastrointestinal (GI) cancers refer to a group of malignancies associated with the GI tract (GIT). Like other solid tumors, hypoxic regions consistently feature inside the GI tumor microenvironment (TME) and contribute towards metabolic reprogramming of tumor-resident cells by modulating hypoxia-induced factors. We highlight here how the metabolic crosstalk between cancer cells and immune cells generate immunosuppressive environment inside hypoxic tumors. Given the fluctuating nature of tumor hypoxia, the metabolic fluxes between immune cells and cancer cells change dynamically. These changes alter cellular phenotypes and functions, resulting in the acceleration of cancer progression. These evolved properties of hypoxic tumors make metabolism-targeting monotherapy approaches or immunotherapy-measures unsuccessful. The current review highlights the advantages of combined immunometabolic treatment strategies to target hypoxic GI cancers and also identifies research areas to develop better combinational therapeutics for future.

Role of Nrf2 Signaling Cascade in Breast Cancer: Strategies and Treatment

Breast cancer is the second leading cancer among all types of cancers. It accounts for 12% of the total cases of cancers. The complex and heterogeneous nature of breast cancer makes it difficult to treat in advanced stages. The expression of various enzymes and proteins is regulated by several molecular pathways. Oxidative stress plays a vital role in cellular events that are generally regulated by nuclear factor erythroid 2-related factor 2 (Nrf2). The exact mechanism of Nrf2 behind cytoprotective and antioxidative properties is still under investigation. In healthy cells, Nrf2 expression is lower, which maintains antioxidative stress; however, cancerous cells overexpress Nrf2, which is associated with various phenomena, such as the development of drug resistance, angiogenesis, development of cancer stem cells, and metastasis. Aberrant Nrf2 expression diminishes the toxicity and potency of therapeutic anticancer drugs and provides cytoprotection to cancerous cells. In this article, we have discussed the attributes associated with Nrf2 in the development of drug resistance, angiogenesis, cancer stem cell generation, and metastasis in the specific context of breast cancer. We also discussed the therapeutic strategies employed against breast cancer exploiting Nrf2 signaling cascades.

Circulating Exosomal miR-181b-5p Promoted Cell Senescence and Inhibited Angiogenesis to Impair Diabetic Foot Ulcer via the Nuclear Factor Erythroid 2-Related Factor 2/Heme Oxygenase-1 Pathway

Endothelial cell dysfunction is the main contributing factor of diabetic foot ulcer (DFU). Circulating exosomes have been found to play an important role in many processes, such as cell senescence and angiogenesis. However, the underlying roles and mechanism of circulating exosomes in the onset and progression of DFU remain unclear. In this study, we isolated exosomes from the plasma of patients with DFU (DFU-Exos) and non-diabetic foot wounds (NDF-Exos). DFU-Exos promoted cell senescence and inhibited tube formation in Human Umbilical Vein Endothelial Cells (HUVECs), unlike NDF-Exos. Several datasets suggest that miR-181b-5p expression might be enriched in exosomes from DFU; this was verified using quantitative real-time PCR (qRT-PCR). We also found that miR-181b-5p, which was taken up by HUVECs, promoted cell senescence and inhibited tube formation. Dual luciferase reporter assay, qRT-PCR, Western blotting, and immunofluorescence staining confirmed that miR-181b-5p could negatively regulate nuclear factor erythroid 2-related factor 2 (NRF2) expression by binding to its 3′ UTR, thus further suppressing heme oxygenase-1 (HO-1) expression. In addition, NRF2 and HO-1 inhibitors could also rescue the effects of senescence and tube formation exerted by miR-181b-5p inhibitor. In vivo experiments showed that exosomes isolated from HUVECs which inhibited miR-181b-5p expression promoted angiogenesis to further restore the capacity of wound healing. In conclusion, this study indicated that circulating exosomal miR-181b-5p promoted cell senescence and inhibited angiogenesis to impair wound healing in DFU by regulating the NRF2/HO-1 pathway.

State of the Art and Future Direction in Diagnosis, Molecular Biology, Genetics, and Treatment of Brain Arteriovenous Malformations

Brain arteriovenous malformations (bAVMs) are uncommon and represent a heterogeneous group of lesions. Although these 2 facts have delayed research on this topic, knowledge about the pathophysiology, diagnosis, and treatment of bAVMs has evolved in recent years. We conducted a review of the literature to update the knowledge about diagnosis, molecular biology, genetic, pathology, and treatment by searching for the following terms: "Epidemiology AND Natural History," "risk of hemorrhage," "intracranial hemorrhage," "diagnosis," "angiogenesis," "molecular genetics," "VEGF," "KRAS," "radiosurgery," "endovascular," "microsurgery," or "surgical resection." Our understanding of bAVMs has significantly evolved in recent years. The latest investigations have helped in defining some molecular pathways involved in the pathology of bAVM. Although there is still more to learn and discover, describing these pathways will allow the creation of targeted treatments that could improve the prognosis of patients with bAVMs.

Paeoniflorin Suppresses TBHP-Induced Oxidative Stress and Apoptosis in Human Umbilical Vein Endothelial Cells via the Nrf2/HO-1 Signaling Pathway and Improves Skin Flap Survival

Random-pattern skin flap is a vital technique frequently applied in reconstruction surgeries for its convenience and effectiveness in solving skin defects. However, ischemic necrosis, especially in the distal areas of the flap, still needs extra attention after surgery. Earlier evidence has suggested that paeoniflorin (PF) could stimulate angiogenesis and suppress ischemic cardiovascular disease. However, few studies have focused on the role of PF in flap survival. In this study, we have demonstrated that the human umbilical vein endothelial cells (HUVECs) treated with PF can alleviate tert-butyl hydroperoxide (TBHP)-stimulated cellular dysfunction and apoptosis. To better evaluate, HUVECs' physiology, cell tube formation, migration, and adhesion were assessed. Mechanistically, PF protects HUVECs against apoptosis via stimulating the nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway. PF also downregulates mitochondrial ROS production to reduce excessive intracellular ROS production induced by TBHP and restore TBHP-induced mitochondrial depolarization. As a result, silencing Nrf2 partially abolishes the protective effect of PF exposure on HUVECs. In in vivo experiments, the oral administration of PF was shown to have enhanced the vascularization of regenerated tissues and promote flap survival. However, the PF-mediated protection was partially lost after co-treatment with ML385, a selective Nrf2 inhibitor, suggesting that PF is a crucial modulator regulating the Nrf2/HO-1 signaling pathway. In summary, our data have provided a new insight into PF as a potential therapy for enhancing random-pattern flap viability.

Si-Wu-Tang facilitates ovarian function through improving ovarian microenvironment and angiogenesis in a mouse model of premature ovarian failure

ETHNOPHARMACOLOGICAL RELEVANCE

Premature ovarian failure (POF) is a severe illness, characterized by premature menopause with a markedly decrease in ovarian function, which leads to infertility. Si-Wu-Tang (SWT), also called "the first prescription of gynecology" by medical experts in China, is widely used as the basic formula in regulating the menstrual cycle and treating infertility. However, the potential effect and underlying mechanisms of action of SWT on the treatment of POF have not yet been elucidated.

PURPOSE

This study aimed to explore the therapeutic effect and underlying molecular mechanism of action of SWT on the treatment of POF in C57BL/6 mice.

MATERIALS AND METHODS

The main compounds of SWT were identified by high-performance liquid chromatography (HPLC). POF model groups were established by a single intraperitoneal injection of cyclophosphamide (Cy, 100 mg/kg). SWT or dehydroepiandrosterone (DHEA) were administered via oral gavage for 28 consecutive days. Ovarian function and pathological changes were evaluated by hormone levels, follicular development, and changes in angiogenesis. Furthermore, statistical analyses of fertility were also performed.

RESULTS

Treatment with SWT significantly improved estrogen levels, the number of follicles, antioxidant defense, and microvascular formation in POF mice. Moreover, SWT significantly activated the Nrf2/HO-1 and STAT3/HIF-1α/VEGF signaling pathways to promote angiogenesis, resulting in a better fertility outcome when compared to the model group.

CONCLUSIONS

Our findings indicated that SWT protected ovarian function of Cy-induced POF mice by improving the antioxidant ability and promoting ovarian angiogenesis, thereby providing scientific evidence for the treatment of POF using SWT.

Interaction of miR-146a-5p with oxidative stress and inflammation in complications of type 2 diabetes mellitus in male rats: Anti-oxidant and anti-inflammatory protection strategies in type 2 diabetic retinopathy

OBJECTIVES

This study aimed to evaluate the role of miR-146a-5p in the pathogenesis of diabetic retinopathy and its interaction with oxidative stress and inflammation in the ocular tissue of rats with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Twenty adult male Sprague Dawley rats (220 ±20 g) were randomly assigned to control and diabetic groups. A high-fat diet was used for three months to induce T2DM which was confirmed by the HOMA-IR index. After that, the levels of glucose and insulin in serum, HOMA-IR as an indicator of insulin resistance, the ocular level of oxidative markers, TNF-α, IL-1β, MIPs, and MCP-1 along with ocular gene expression of NF-κB, Nrf2, and miR-146a-5p were evaluated.

RESULTS

The level of lipid peroxidation along with metabolic and inflammatory factors significantly increased and the antioxidant enzyme activity significantly decreased in diabetic rats (P<0.05). The ocular expression of NF-κB and TNF-α increased and Nrf2, HO-1, and miR-146a-5p expression decreased in diabetic rats (P<0.05). In addition, a negative correlation between miR-146a-5p expression with NF-κB and HOMA-IR and a positive correlation between miR-146a-5p with Nrf2 were observed.

CONCLUSION

It can be concluded that miR-146a-5p may regulate Nrf2 and NF-κB expression and inflammation and oxidative stress in the ocular tissue of diabetic rats.

Crosstalk in oxygen homeostasis networks: SKN-1/NRF inhibits the HIF-1 hypoxia-inducible factor in Caenorhabditis elegans

During development, homeostasis, and disease, organisms must balance responses that allow adaptation to low oxygen (hypoxia) with those that protect cells from oxidative stress. The evolutionarily conserved hypoxia-inducible factors are central to these processes, as they orchestrate transcriptional responses to oxygen deprivation. Here, we employ genetic strategies in C. elegans to identify stress-responsive genes and pathways that modulate the HIF-1 hypoxia-inducible factor and facilitate oxygen homeostasis. Through a genome-wide RNAi screen, we show that RNAi-mediated mitochondrial or proteasomal dysfunction increases the expression of hypoxia-responsive reporter Pnhr-57::GFP in C. elegans. Interestingly, only a subset of these effects requires hif-1. Of particular importance, we found that skn-1 RNAi increases the expression of hypoxia-responsive reporter Pnhr-57::GFP and elevates HIF-1 protein levels. The SKN-1/NRF transcription factor has been shown to promote oxidative stress resistance. We present evidence that the crosstalk between HIF-1 and SKN-1 is mediated by EGL-9, the prolyl hydroxylase that targets HIF-1 for oxygen-dependent degradation. Treatment that induces SKN-1, such as heat or gsk-3 RNAi, increases expression of a Pegl-9::GFP reporter, and this effect requires skn-1 function and a putative SKN-1 binding site in egl-9 regulatory sequences. Collectively, these data support a model in which SKN-1 promotes egl-9 transcription, thereby inhibiting HIF-1. We propose that this interaction enables animals to adapt quickly to changes in cellular oxygenation and to better survive accompanying oxidative stress.

TCF11 Has a Potent Tumor-Repressing Effect Than Its Prototypic Nrf1α by Definition of Both Similar Yet Different Regulatory Profiles, With a Striking Disparity From Nrf2

Nrf1 and Nrf2, as two principal CNC-bZIP transcription factors, regulate similar but different targets involved in a variety of biological functions for maintaining cell homeostasis and organ integrity. Of note, the unique topobiological behavior of Nrf1 makes its functions more complicated than Nrf2, because it is allowed for alternatively transcribing and selectively splicing to yield multiple isoforms (e.g., TCF11, Nrf1α). In order to gain a better understanding of their similarities and differences in distinct regulatory profiles, all four distinct cell models for stably expressing TCF11, TCF11^ΔN , Nrf1α or Nrf2 have been herein established by an Flp-In™ T-REx™-293 system and then identified by transcriptomic sequencing. Further analysis revealed that Nrf1α and TCF11 have similar yet different regulatory profiles, although both contribute basically to positive regulation of their co-targets, which are disparate from those regulated by Nrf2. Such disparity in those gene regulations by Nrf1 and Nrf2 was further corroborated by scrutinizing comprehensive functional annotation of their specific and/or common target genes. Conversely, the mutant TCF11^ΔN, resulting from a deletion of the N-terminal amino acids 2-156 from TCF11, resembles Nrf2 with the largely consistent structure and function. Interestingly, our further experimental evidence demonstrates that TCF11 acts as a potent tumor-repressor relative to Nrf1α, albeit both isoforms possess a congruous capability to prevent malignant growth of tumor and upregulate those genes critical for improving the survival of patients with hepatocellular carcinoma.

Overcoming hypoxia-induced resistance of pancreatic and lung tumor cells by disrupting the PERK-NRF2-HIF-axis

Hypoxia-induced resistance of tumor cells to therapeutic treatment is an unresolved limitation due to poor vascular accessibility and protective cell adaptations provided by a network, including PERK, NRF2, and HIF signaling. All three pathways have been shown to influence each other, but a detailed picture remains elusive. To explore this crosstalk in the context of tumor therapy, we generated human cancer cell lines of pancreatic and lung origin carrying an inducible shRNA against NRF2 and PERK. We report that PERK-related phosphorylation of NRF2 is only critical in Keap1 wildtype cells to escape its degradation, but shows no direct effect on nuclear import or transcriptional activity of NRF2. We could further show that NRF2 is paramount for proliferation, ROS elimination, and radioprotection under constant hypoxia (1% O₂), but is dispensable under normoxic conditions or after reoxygenation. Depletion of NRF2 does not affect apoptosis, cell cycle progression and proliferation factors AKT and c-Myc, but eliminates cellular HIF-1α signaling. Co-IP experiments revealed a protein interaction between NRF2 and HIF-1α and strongly suggest NRF2 as one of the cellular key factor for the HIF pathway. Together these data provide new insights on the complex role of the PERK-NRF2-HIF-axis for cancer growth.

Improvement of cerebral ischemia-reperfusion injury by L-3-n-butylphthalide through promoting angiogenesis

Cerebral ischemia/reperfusion (I/R) injury may lead to a poor prognosis for ischemic stroke patients after reperfusion therapy, and currently, lacks effective therapeutic intervention. This study aimed to investigate the effects of L-3-n-butylphthalide (L-NBP) on cerebral I/R injury in rats. Rat models of cerebral I/R injury were established using the middle cerebral artery occlusion/refusion (MACO/R) surgery and were administrated intragastrically with L-NBP or vehicle. We found that L-NBP attenuated the histological damages and reduced the brain hematoma in MACO/R rats. L-NBP also significantly improved the neurological function, alleviated the brain edema, and reduced the permeability of blood-brain barrier of MACO/R rats. Moreover, we detected that L-NBP considerably facilitated microvessel formation in the lesion area of brain in MACO/R rats. Finally, we found that L-NBP significantly increased the protein and mRNA expression levels of Nrf2, HIF-1α, and VEGF in the brain of MACO/R rats. In conclusion, our results demonstrated that L-NBP exerted significant beneficial effects on cerebral I/R injury in rats through promoting angiogenesis, which may be associated with the activation of Nrf2/HIF-1α/VEGF signaling pathway. Our results suggested that L-NBP could be a potential therapeutic drug for cerebral I/R injury.

Targeting Transcription Factor Nrf2 (Nuclear Factor Erythroid 2-Related Factor 2) for the Intervention of Vascular Cognitive Impairment and Dementia

Vascular cognitive impairment and dementia (VCID) is an age-related, mild to severe mental disability due to a broad panel of cerebrovascular disorders. Its pathobiology involves neurovascular dysfunction, blood-brain barrier disruption, white matter damage, microRNAs, oxidative stress, neuroinflammation, and gut microbiota alterations, etc. Nrf2 (Nuclear factor erythroid 2-related factor 2) is the master regulator of redox status and controls the transcription of a panel of antioxidative and anti-inflammatory genes. By interacting with NF-κB (nuclear factor-κB), Nrf2 also fine-tunes the cellular oxidative and inflammatory balance. Aging is associated with Nrf2 dysfunction, and increasing evidence has proved the role of Nrf2 in mitigating the VCID process. Based on VCID pathobiologies and Nrf2 studies from VCID and other brain diseases, we point out several hypothetical Nrf2 targets for VCID management, including restoration of endothelial function and neurovascular coupling, preservation of blood-brain barrier integrity, reduction of amyloidopathy, promoting white matter integrity, and mitigating oxidative stress and neuroinflammation. Collectively, the Nrf2 pathway could be a promising direction for future VCID research. Targeting Nrf2 would shed light on VCID managing strategies.

Role of Nrf2 in MALAT1/ HIF-1α loop on the regulation of angiogenesis in diabetic foot ulcer

Diabetic non healing wounds often result in significant morbidity and mortality. The number of effective targets to detect these wounds are meagre. Slow lymphangiogenesis is one of the complex processes involved in impaired healing of wounds. Long non coding RNAs (lncRNAs) have been importantly recognized for their role in pathological conditions. Multiple studies highlighting the role of lncRNAs in the regulation of several biological processes and complex diseases. Herein, we investigated the role of lncRNA Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in the progression of diabetic foot ulcer (DFU). We report a significant reduction in the expression of lncRNA MALAT1 in the infected DFU subjects which was positively correlated with the expression of angiogenic factors such as Nrf2, HIF-1α and VEGF. Further, expression of pro-inflammatory markers TNF-α and IL-6 were found to be increased while, the expression of anti-inflammatory marker IL-10 was decreased in infected DFU tissues. Involvement of lncRNA MALAT1 in angiogenesis in EA.hy926 cells was demonstrated by silencing the expression of Nrf2, HIF-1α, and VEGF through interference mediated by MALAT1. In addition, its inflammatory role was demonstrated by decreased expression of TNF-α, IL-6 and not affecting the expression of IL-10. Further, CRISPR-Cas9 knock out of Nrf2 decreased the expression of lncRNA MALAT1, HIF-1α and VEGF which revealed the association of Nrf2 in regulating MALAT1/HIF-1α loop through positive feedback mechanism. Collectively, our results suggested the role of Nrf2 on MALAT1/HIF-1α loop in the regulation of angiogenesis, which could act as a novel target in the treatment of diabetic wounds.

miR-18a Inhibits BMP4 and HIF-1α Normalizing Brain Arteriovenous Malformations

RATIONALE

Brain arteriovenous malformations (AVMs) are abnormal tangles of vessels where arteries and veins directly connect without intervening capillary nets, increasing the risk of intracerebral hemorrhage and stroke. Current treatments are highly invasive and often not feasible. Thus, effective noninvasive treatments are needed. We previously showed that AVM-brain endothelial cells (BECs) secreted higher VEGF (vascular endothelial growth factor) and lower TSP-1 (thrombospondin-1) levels than control BEC; and that microRNA-18a (miR-18a) normalized AVM-BEC function and phenotype, although its mechanism remained unclear.

OBJECTIVE

To elucidate the mechanism of action and potential clinical application of miR-18a as an effective noninvasive treatment to selectively restore the phenotype and functionality of AVM vasculature.

METHODS AND RESULTS

The molecular pathways affected by miR-18a in patient-derived BECs and AVM-BECs were determined by Western blot, RT-qPCR (quantitative reverse transcription polymerase chain reaction), ELISA, co-IP, immunostaining, knockdown and overexpression studies, flow cytometry, and luciferase reporter assays. miR-18a was shown to increase TSP-1 and decrease VEGF by reducing PAI-1 (plasminogen activator inhibitor-1/SERPINE1) levels. Furthermore, miR-18a decreased the expression of BMP4 (bone morphogenetic protein 4) and HIF-1α (hypoxia-inducible factor 1α), blocking the BMP4/ALK (activin-like kinase) 2/ALK1/ALK5 and Notch signaling pathways. As determined by Boyden chamber assays, miR-18a also reduced the abnormal AVM-BEC invasiveness, which correlated with a decrease in MMP2 (matrix metalloproteinase 2), MMP9, and ADAM10 (ADAM metallopeptidase domain 10) levels. In vivo pharmacokinetic studies showed that miR-18a reaches the brain following intravenous and intranasal administration. Intranasal co-delivery of miR-18a and NEO100, a good manufacturing practices-quality form of perillyl alcohol, improved the pharmacokinetic profile of miR-18a in the brain without affecting its pharmacological properties. Ultra-high-resolution computed tomography angiography and immunostaining studies in an Mgp^-/- AVM mouse model showed that miR-18a decreased abnormal cerebral vasculature and restored the functionality of the bone marrow, lungs, spleen, and liver.

CONCLUSIONS

miR-18a may have significant clinical value in preventing, reducing, and potentially reversing AVM.

Oxidative Stress Induces a VEGF Autocrine Loop in the Retina: Relevance for Diabetic Retinopathy

BACKGROUND

Oxidative stress (OS) plays a central role in diabetic retinopathy (DR), triggering expression and release of vascular endothelial growth factor (VEGF), the increase of which leads to deleterious vascular changes. We tested the hypothesis that OS-stimulated VEGF induces its own expression with an autocrine mechanism.

METHODS

MIO-M1 cells and ex vivo mouse retinal explants were treated with OS, with exogenous VEGF or with conditioned media (CM) from OS-stressed cultures.

RESULTS

Both in MIO-M1 cells and in retinal explants, OS or exogenous VEGF induced a significant increase of VEGF mRNA, which was abolished by VEGF receptor 2 (VEGFR-2) inhibition. OS also caused VEGF release. In MIO-M1 cells, CM induced VEGF expression, which was abolished by a VEGFR-2 inhibitor. Moreover, the OS-induced increase of VEGF mRNA was abolished by a nuclear factor erythroid 2-related factor 2 (Nrf2) blocker, while the effect of exo-VEGF resulted Nrf2-independent. Finally, both the exo-VEGF- and the OS-induced increase of VEGF expression were blocked by a hypoxia-inducible factor-1 inhibitor.

CONCLUSIONS

These results are consistent with the existence of a retinal VEGF autocrine loop triggered by OS. This mechanism may significantly contribute to the maintenance of elevated VEGF levels and therefore it may be of central importance for the onset and development of DR.

Sestrin2 promotes angiogenesis to alleviate brain injury by activating Nrf2 through regulating the interaction between p62 and Keap1 following photothrombotic stroke in rats

AIMS

The lack of effective treatments for ischemic stroke is concerning. Here, we aimed to examine the protective effects of sestrin2 in ischemic stroke and determine the mechanism by which sestrin2 attenuates cerebral injuries.

MAIN METHODS

Ischemic stroke was induced in Sprague-Dawley rats using a photothrombotic ischemia (PTI) model. After sestrin2 was overexpressed or silenced, neurological deficits and brain infarction were evaluated. Cerebral angiogenesis and the expression of related proteins were examined by Western blotting and immunofluorescence. The interaction between p62 and Keap1 was measured by coimmunoprecipitation (CoIP) and an in situ proximity ligation assay (PLA).

KEY FINDINGS

The overexpression of sestrin2 was found to improve the neurological function of rats 10 days after PTI and to reduce the infarct volume and brain edema in rats 10 days after PTI. It was shown that upregulating sestrin2 enhanced the relative immunofluorescence intensity of CD34, CD31 and DCX. Sestrin2 overexpressionalso increased the number and total length of CD34 and CD31 positive vessels and the expression of nuclear and total Nrf2, HO-1, VEGF and p62. However, downregulating sestrin2 induced almost the opposite results. Furthermore, we demonstrated that sestrin2 increased the interaction between p62 and Keap1.

SIGNIFICANCE

Based on our data, sestrin2 may promote angiogenesis by activating the Nrf2 pathway through increasing the interaction between p62 and Keap1 via upregulating p62 expression.

PTEN inhibitor VO-OHpic attenuates GC-associated endothelial progenitor cell dysfunction and osteonecrosis of the femoral head via activating Nrf2 signaling and inhibiting mitochondrial apoptosis pathway

Background

Glucocorticoid (GC)-associated osteonecrosis of the femoral head (ONFH) is the most common in non-traumatic ONFH. Despite a strong relationship between GC and ONFH, the detailed mechanisms have remained elusive. Recent studies have shown that GC could directly injure the blood vessels and reduce blood supply in the femoral head. Endothelial progenitor cells (EPCs), which were inhibited quantitatively and functionally during ONFH, play an important role in maintaining the normal structure and function of vascular endothelium. Phosphatase and tensin homolog (PTEN) is a tumor suppressor gene that promotes cell apoptosis, and its expression was found to be elevated in GC-associated ONFH patients. However, whether direct inhibition of PTEN attenuates GC-associated apoptosis and dysfunction of the EPCs remains largely unknown.

Methods

We investigated the effect of, VO-OHpic, a potent inhibitor of PTEN, in attenuating GC-associated apoptosis and dysfunction of EPCs and the molecular mechanism. SD rats were used to study the effect of VO-OHpic on angiogenesis and osteonecrosis in vivo.

Results

The results revealed that methylprednisolone (MPS) obviously inhibit angiogenesis of EPCs by inducing apoptosis, destroying the normal mitochondrial structure, and disrupting function of mitochondria. VO-OHpic treatment is able to reverse the harmful effects by inhibiting the mitochondrial apoptosis pathway and activating the NF-E2-related factor 2 (Nrf2) signaling. Si-Nrf2 transfection significantly reduced the protective effects of VO-OHpic on EPCs. Our in vivo studies also showed that intraperitoneal injection of VO-OHpic obviously attenuates the osteonecrosis of the femoral head induced by MPS and potently increases the blood supply in the femoral head.

Conclusion

Taken together, the data suggests that inhibition of PTEN with VO-OHpic attenuates apoptosis and promotes angiogenesis of EPCs in vitro via activating Nrf2 signaling pathway and inhibiting the mitochondrial apoptosis pathway. Moreover, VO-OHpic also mitigates GC-associated ONFH and potentiates angiogenesis in the femoral head.

Potential Applications of NRF2 Modulators in Cancer Therapy

The nuclear factor erythroid 2-related factor 2 (NRF2)-Kelch-like ECH-associated protein 1 (KEAP1) regulatory pathway plays an essential role in protecting cells and tissues from oxidative, electrophilic, and xenobiotic stress. By controlling the transactivation of over 500 cytoprotective genes, the NRF2 transcription factor has been implicated in the physiopathology of several human diseases, including cancer. In this respect, accumulating evidence indicates that NRF2 can act as a double-edged sword, being able to mediate tumor suppressive or pro-oncogenic functions, depending on the specific biological context of its activation. Thus, a better understanding of the mechanisms that control NRF2 functions and the most appropriate context of its activation is a prerequisite for the development of effective therapeutic strategies based on NRF2 modulation. In line of principle, the controlled activation of NRF2 might reduce the risk of cancer initiation and development in normal cells by scavenging reactive-oxygen species (ROS) and by preventing genomic instability through decreased DNA damage. In contrast however, already transformed cells with constitutive or prolonged activation of NRF2 signaling might represent a major clinical hurdle and exhibit an aggressive phenotype characterized by therapy resistance and unfavorable prognosis, requiring the use of NRF2 inhibitors. In this review, we will focus on the dual roles of the NRF2-KEAP1 pathway in cancer promotion and inhibition, describing the mechanisms of its activation and potential therapeutic strategies based on the use of context-specific modulation of NRF2.

Control of tumor angiogenesis and metastasis through modulation of cell redox state

Redox reactions pervade all biology. The control of cellular redox state is essential for bioenergetics and for the proper functioning of many biological functions. This review traces a timeline of findings regarding the connections between redox and cancer. There is ample evidence of the involvement of cellular redox state on the different hallmarks of cancer. Evidence of the control of tumor angiogenesis and metastasis through modulation of cell redox state is reviewed and highlighted.

Challenging dogma: report of a spinal cord arteriovenous malformation as an acquired lesion in a pediatric patient

Spinal cord intramedullary arteriovenous malformations (AVMs) have classically been considered congenital lesions that are present from birth. The reason for this dogmatic principal is the fact that a vast majority of these lesions present in pediatric and young adult patients. Interestingly, while many authors have demonstrated the development of de novo nidus-type brain AVMs, there have been no reported cases of a de novo intramedullary or perimedullary AVM of the spine. In this paper the authors describe what they believe to be the first reported case of a de novo AVM of the spinal cord in a young patient who underwent serial imaging from birth for evaluation of a syrinx. Potential pathophysiological mechanisms for the development of de novo vascular malformations of the spinal cord are discussed.

Plasma Medicine: A Field of Applied Redox Biology

Plasma medicine comprises the application of physical plasma directly on or in the human body for therapeutic purposes. Three most important basic plasma effects are relevant for medical applications: i) inactivation of a broad spectrum of microorganisms, including multidrug-resistant pathogens, ii) stimulation of cell proliferation and angiogenesis with lower plasma treatment intensity, and iii) inactivation of cells by initialization of cell death with higher plasma treatment intensity, above all in cancer cells. Based on own published results as well as on monitoring of relevant literature the aim of this topical review is to summarize the state of the art in plasma medicine and connect it to redox biology. One of the most important results of basic research in plasma medicine is the insight that biological plasma effects are mainly mediated via reactive oxygen and nitrogen species influencing cellular redox-regulated processes. Plasma medicine can be considered a field of applied redox biology.

Risk factors for hemorrhage of brain arteriovenous malformation

Patients with brain arteriovenous malformation (bAVM) are at risk of intracranial hemorrhage (ICH). Overall, bAVM accounts for 25% of hemorrhagic strokes in adults <50 years of age. The treatment of unruptured bAVMs has become controversial, because the natural history of these patients may be less morbid than invasive therapies. Available treatments include observation, surgical resection, endovascular embolization, stereotactic radiosurgery, or combination thereof. Knowing the risk factors for bAVM hemorrhage is crucial for selecting appropriate therapeutic strategies. In this review, we discussed several biological risk factors, which may contribute to bAVM hemorrhage.

TTB Protects Astrocytes Against Oxygen-Glucose Deprivation/Reoxygenation-Induced Injury via Activation of Nrf2/HO-1 Signaling Pathway

Neonatal hypoxic/ischemic encephalopathy (NHIE) is a severe condition that leads to death or neurological disability in newborns. The underlying pathological mechanisms are unclear, and developing the target neuroprotective strategies are urgent. 2,7,2′-trihydroxy-4,4′7′-trimethoxy-1,1′-biphenanthrene (TTB) is a natural product isolated from Cremastra appendiculata (D. Don) Makino and Liparis nervosa (Thunb.) Lindl. TTB has demonstrated potent cytotoxic activity against stomach (HGC-27) and colon (HT-29) cancer cell lines. However, none of the studies have addressed the effects of TTB in NHIE. In the present study, an oxygen-glucose deprivation/reoxygenation (OGD/R)-induced astrocyte injury model was established to investigate the effect of TTB and its potential mechanisms. Our results showed that TTB alleviated the OGD/R-induced reactive oxygen species increase and the intracellular antioxidant capacity of superoxide dismutase activity decrease. Moreover, TTB potentially prolonged the activation state of the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway and maintained the protection against oxidative stress in OGD/R-induced astrocytes by inducing the nuclear translocation and up-regulation of Nrf2 along with the enhanced expression of the downstream target gene HO-1. Furthermore, TTB treatment diminished the accumulation of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) expression induced by OGD/R. We also found TTB-treated astrocytes reversed the inhibition of OGD/R on neurite growth of neurons by the astrocyte-neuron coculture system. In conclusion, TTB inhibited the OGD/R-induced astrocyte oxidative stress at least partially through the inhibition of HIF-1α and VEGF via the Nrf2/HO-1 signaling pathway.

Astaxanthin Complexes to Attenuate Muscle Damage after In Vivo Femoral Ischemia-Reperfusion

(1) Background: Reperfusion injury refers to the cell and tissue damage induced, when blood flow is restored after an ischemic period. While reperfusion reestablishes oxygen supply, it generates a high concentration of radicals, resulting in tissue dysfunction and damage. Here, we aimed to challenge and achieve the potential of a delivery system based on astaxanthin, a natural antioxidant, in attenuating the muscle damage in an animal model of femoral hind-limb ischemia and reperfusion. (2) Methods: The antioxidant capacity and non-toxicity of astaxanthin was validated before and after loading into a polysaccharide scaffold. The capacity of astaxanthin to compensate stress damages was also studied after ischemia induced by femoral artery clamping and followed by varied periods of reperfusion. (3) Results: Histological evaluation showed a positive labeling for CD68 and CD163 macrophage markers, indicating a remodeling process. In addition, higher levels of Nrf2 and NQO1 expression in the sham group compared to the antioxidant group could reflect a reduction of the oxidative damage after 15 days of reperfusion. Furthermore, non-significant differences were observed in non-heme iron deposition in both groups, reflecting a cell population susceptible to free radical damage. (4) Conclusions: Our results suggest that the in situ release of an antioxidant molecule could be effective in improving the antioxidant defenses of ischemia/reperfusion (I/R)-damaged muscles.