Knockdown of Nrf2 inhibits angiogenesis by downregulating VEGF expression through PI3K/Akt signaling pathway in cerebral microvascular endothelial cells under hypoxic conditions

The cell-specific roles of Nrf2 in acute and chronic phases of ischemic stroke

Ischemic stroke refers to the sudden loss of blood flow in a specific area of the brain. It is the fifth leading cause of mortality and the leading cause of permanent disability. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) controls the production of several antioxidants and protective proteins and it has been investigated as a possible pharmaceutical target for reducing harmful oxidative events in brain ischemia. Each cell type exhibits different roles and behaviors in different phases post-stroke, which is comprehensive yet important to understand to optimize management strategies and goals for care for stroke patients. In this review, we comprehensively summarize the protective effects of Nrf2 in experimental ischemic stroke, emphasizing the role of Nrf2 in different cell types including neurons, astrocytes, oligodendrocytes, microglia, and endothelial cells during acute and chronic phases of stroke and providing insights on the neuroprotective role of Nrf2 on each cell type throughout the long term of stroke care. We also highlight the importance of targeting Nrf2 in clinical settings while considering a variety of important factors such as age, drug dosage, delivery route, and time of administration.

MicroRNAs as the critical regulators of tumor angiogenesis in liver cancer

Liver cancer is one of the most common malignancies in human digestive system. Despite the recent therapeutic methods, there is a high rate of mortality among liver cancer patients. Late diagnosis in the advanced tumor stages can be one of the main reasons for the poor prognosis in these patients. Therefore, investigating the molecular mechanisms of liver cancer can be helpful for the early stage tumor detection and treatment. Vascular expansion in liver tumors can be one of the important reasons for poor prognosis and aggressiveness. Therefore, anti-angiogenic drugs are widely used in liver cancer patients. MicroRNAs (miRNAs) have key roles in the regulation of angiogenesis in liver tumors. Due to the high stability of miRNAs in body fluids, these factors are widely used as the non-invasive diagnostic and prognostic markers in cancer patients. Regarding, the importance of angiogenesis during liver tumor growth and invasion, in the present review, we discussed the role of miRNAs in regulation of angiogenesis in these tumors. It has been reported that miRNAs mainly exert an anti-angiogenic function by regulation of tumor microenvironment, transcription factors, and signaling pathways in liver tumors. This review can be an effective step to suggest the miRNAs for the non-invasive early detection of malignant and invasive liver tumors.

Curcumin in vitro Neuroprotective Effects Are Mediated by p62/keap-1/Nrf2 and PI3K/AKT Signaling Pathway and Autophagy Inhibition

Oxidative stress and autophagy are potential mechanisms associated with cerebral ischemia/reperfusion injury (IRI) and is usually linked to inflammatory responses and apoptosis. Curcumin has recently been demonstrated to exhibit anti-inflammatory, anti-oxidant, anti-apoptotic and autophagy regulation properties. However, mechanism of curcumin on IRI-induced oxidative stress and autophagy remains not well understood. We evaluated the protective effects and potential mechanisms of curcumin on cerebral microvascular endothelial cells (bEnd.3) and neuronal cells (HT22) against oxygen glucose deprivation/reoxygenation (OGD/R) in vitro models that mimic in vivo cerebral IRI. The cell counting kit-8 (CCK-8) and lactate dehydrogenase (LDH) activity assays revealed that curcumin attenuated the OGD/R-induced injury in a dose-specific manner. OGD/R induced elevated levels of inflammatory cytokines TNF-alpha, IL-6 as well as IL-1beta, and these effects were notably reduced by curcumin. OGD/R-mediated apoptosis was suppressed by curcumin via upregulating B-cell lymphoma-2 (Bcl-2) and downregulating Bcl-associated X (Bax), cleaved-caspase3 and TUNEL apoptosis marker. Additionally, curcumin increased superoxide dismutase (SOD) and glutathione (GSH), but suppressed malondialdehyde (MDA) and reactive oxygen species (ROS) content. Curcumin inhibited the levels of autophagic biomarkers such as LC3 II/LC3 I and Beclin1. Particularly, curcumin induced p62 accumulation and its interactions with keap1 and promoted NF-E2-related factor 2 (Nrf2) translocation to nucleus, accompanied by increased NADPH quinone dehydrogenase (Nqo1) and heme oxygenase 1 (HO-1). Treatment of curcumin increased phosphorylation-phosphatidylinositol 3 kinase (p-PI3K) and p-protein kinase B (p-AKT). The autophagy inhibitor 3-methyladenine (3-MA) activated the keap-1/Nrf2 and PI3K/AKT pathways. This study highlights the neuroprotective effects of curcumin on cerebral IRI.

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.

The Role of Nrf2 in Relieving Cerebral Ischemia-Reperfusion Injury

Ischemic stroke includes two related pathological damage processes: brain injury caused by primary ischemia and secondary ischemia reperfusion (I/R) injury. I/R injury has become a worldwide health problem. Unfortunately, there is still a lack of satisfactory drugs for ameliorating cerebral I/R damage. Nrf2 is a vital endogenous antioxidant protein, which combines with Keap1 to maintain a dormant state under physiological conditions. When pathological changes such as I/R occurs, Nrf2 dissociates from Keap1 and activates the expression of downstream antioxidant proteins to exert a protective effect. Recent research have shown that the activated Nrf2 not only effectively inhibits oxidative stress, but also performs the ability to repair the function of compromised mitochondria, alleviate endoplasmic reticulum stress, eliminate inflammatory response, reduce blood-brain barrier permeability, inhibit neuronal apoptosis, enhance the neural network remolding, thereby exerting significant protective effects in alleviating the injuries caused by cell oxygen-glucose deprivation, or animal cerebral I/R. However, no definite clinical application report demonstrated the efficacy of Nrf2 activators in the treatment of cerebral I/R. Therefore, further efforts are needed to elaborate the role of Nrf2 activators in the treatment of cerebral I/R. Here, we reviewed the possible mechanisms underlying its potential pharmacological benefits in alleviating cerebral I/R injury, so as to provide a theoretical basis for studying its mechanism and developing Nrf2 activators.

Nrf2 Pathway and Autophagy Crosstalk: New Insights into Therapeutic Strategies for Ischemic Cerebral Vascular Diseases

Cerebrovascular disease is highly prevalent and has a complex etiology and variable pathophysiological activities. It thus poses a serious threat to human life and health. Currently, pathophysiological research on cerebrovascular diseases is gradually improving, and oxidative stress and autophagy have been identified as important pathophysiological activities that are gradually attracting increasing attention. Many studies have found some effects of oxidative stress and autophagy on cerebrovascular diseases, and studies on the crosstalk between the two in cerebrovascular diseases have made modest progress. However, further, more detailed studies are needed to determine the specific mechanisms. This review discusses nuclear factor erythroid 2-related factor 2 (Nrf2) molecules, which are closely associated with oxidative stress and autophagy, and the crosstalk between them, with the aim of providing clues for studying the two important pathophysiological changes and their crosstalk in cerebrovascular diseases as well as exploring new target treatments.

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.

Ruscogenin protects against deoxynivalenol-Induced hepatic injury by inhibiting oxidative stress, inflammation, and apoptosis through the Nrf2 signaling pathway: An In vitro study

Background

Deoxynivalenol (DON) is a trichothecene mycotoxin with demonstrated cytotoxicity in several cell lines and animals, primarily owing to inflammation and reactive oxygen species accumulation. Ruscogenin (RGN), a steroidal sapogenin of Radix Ophiopogon japonicus, has significant anti-thrombotic/anti-inflammatory effects.

Objective:

The aim of this study was to assess the protective role of RGN against DON-induced oxidative stress, which occurs through the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway and is regulated by phosphoinositide 3-kinases/protein kinase B (PI3K/AKT).

Methods:

The effects were examined using the HepG2 cell line. RGN and DON were suspended in serum-free medium. Cells were seeded onto plates, and then RGN, DON, or both were added over 24 h in triplicates for each group.

Results:

RGN conferred protection against DON-exhibited cytotoxicity against HepG2 cells. RGN pretreatment downregulated the expression of DON-induced TNF-α and COX-2 and the formation of reactive oxygen species in a dose-dependent manner. RGN upregulated the expression of Nrf2 and its antioxidant proteins as well as mRNA levels of HO-1/NQO-1/HO-1/Nrf2. Similarly, treatment with DON + RGN resulted in upregulation of the pI3K/pAKT signaling pathway in a dose-dependent manner. Finally, RGN was also found to inhibit the DON-induced apoptosis by upregulating the levels of cleaved proteins and downregulating the expression of Bcl2.

Conclusion:

The study demonstrates that RGN suppresses hepatic cell injury induced by oxidative stress through Nrf2 via activation of the pI3K/AKT signaling pathway.

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.

Lipid-induced DRAM recruits STOM to lysosomes and induces LMP to promote exosome release from hepatocytes in NAFLD

The biogenesis and diagnostic value of exosomes in nonalcoholic fatty liver disease (NAFLD) are unclear. In this study, we revealed that the plasma exosome level was higher in patients with NAFLD than that in healthy controls. Damage-regulated autophagy modulator (DRAM) was identified as one of the genes related to exosome secretion in patients with NAFLD. Then, loss or knockdown of DRAM down-regulated exosome secretion from hepatic cells using a knockout mouse model and a knockdown cell model. DRAM knockout reversed high-fat diet–induced increase of secreted exosomes. Furthermore, DRAM knockdown inhibited fatty acid (FA)–induced lysosomal membrane permeabilization and lysosome inhibitor reversed the down-regulation of exosome release in DRAM knockout mice. Last, FA-induced DRAM interacted with stomatin and promoted its lysosomal localization to enhance exosome secretion from hepatic cells. We revealed a DRAM-mediated mechanism for exosome secretion and provided the foundation for plasma exosomes as a potential biomarker for NAFLD.

ITLN1 inhibits tumor neovascularization and myeloid derived suppressor cells accumulation in colorectal carcinoma

Low levels of ITLN1 have been correlated with obesity-related colorectal carcinogenesis, however, the specific functions and underlying mechanisms remain unclear. Thus, we sought to explore the inhibitory role of ITLN1 in the tumor-permissive microenvironment that exists during the first occurrence and subsequent development of colorectal carcinoma (CRC). Results indicated that ITLN1 was frequently lost in CRC tissues and ITLN1 to be an independent prognostic predictor of CRC. Orthotopic and subcutaneous tumor xenograft approaches were then used to further confirm the protective role of ITLN1 during tumor progression. Increased ITLN1 expression in CRC cells significantly inhibited local pre-existing vessels sprouting, EPC recruitment and the infiltration of immunosuppressive myeloid-derived suppressor cells (MDSCs) into tumor tissues without affecting the behavior of CRC cells in vitro. Comparatively, ITLN1-derived MDSCs had a lower suppressive effect on T cell proliferation, NOS2 expression, and ROS production. In addition, ITLN1 overexpression markedly suppressed bone marrow (BM)-derived hematopoietic progenitor cells (HPC) differentiation into MDSCs as well as NOS2 activity on MDSCs. Using H-2b+YFP + chimerism through bone marrow transplantation, increased ITLN1 in HCT116 significantly reduced the BM-derived EPCs and MDSCs in vivo mobilization. Mechanistically, results indicated ITLN1 inhibited tumor-derived IL-17D and CXCL2 (MIP2) through the KEAP1/Nrf2/ROS/IL-17D and p65 NF-ĸB/CXCL2 signaling cascades dependent on PI3K/AKT/GSK3ß. This effect was reversed by the PI3K selective inhibitor LY294002. Collectively, ITLN1 synergistically suppressed IL-17D and CXCL2-mediated tumor vascularization, bone marrow derived EPC recruitment, as well as MDSCs generation and trafficking. Thus, ITLN1 potentially serves as a critical prognostic and therapeutic target for CRC.

Use of dual-flow bioreactor to develop a simplified model of nervous-cardiovascular systems crosstalk: A preliminary assessment

Chronic conditions requiring long-term rehabilitation therapies, such as hypertension, stroke, or cancer, involve complex interactions between various systems/organs of the body and mutual influences, thus implicating a multiorgan approach. The dual-flow IVTech LiveBox2 bioreactor is a recently developed inter-connected dynamic cell culture model able to mimic organ crosstalk, since cells belonging to different organs can be connected and grown under flow conditions in a more physiological environment. This study aims to setup for the first time a 2-way connected culture of human neuroblastoma cells, SH-SY5Y, and Human Coronary Artery Smooth Muscle Cells, HCASMC through a dual-flow IVTech LiveBox2 bioreactor, in order to represent a simplified model of nervous-cardiovascular systems crosstalk, possibly relevant for the above-mentioned diseases. The system was tested by treating the cells with 10nM angiotensin II (AngII) inducing PKCβII/HuR/VEGF pathway activation, since AngII and PKCβII/HuR/VEGF pathway are relevant in cardiovascular and neuroscience research. Three different conditions were applied: 1- HCASMC and SH-SY5Y separately seeded in petri dishes (static condition); 2- the two cell lines separately seeded under flow (dynamic condition); 3- the two lines, seeded in dynamic conditions, connected, each maintaining its own medium, with a membrane as interface for biohumoral changes between the two mediums, and then treated. We detected that only in condition 3 there was a synergic AngII-dependent VEGF production in SH-SY5Y cells coupled to an AngII-dependent PKCβII/HuR/VEGF pathway activation in HCASMC, consistent with the observed physiological response in vivo. HCASMC response to AngII seems therefore to be generated by/derived from the reciprocal cell crosstalk under the dynamic inter-connection ensured by the dual flow LiveBox 2 bioreactor. This system can represent a useful tool for studying the crosstalk between organs, helpful for instance in rehabilitation research or when investigating chronic diseases; further, it offers the advantageous opportunity of cultivating each cell line in its own medium, thus mimicking, at least in part, distinct tissue milieu.

The protective effects of memantine against inflammation and impairment of endothelial tube formation induced by oxygen-glucose deprivation/reperfusion

Acute myocardial infarction (AMI) is one of the leading causes of death and disability. The dysregulation of cardiac endothelial cells plays a significant role in the pathogenesis of AMI. In the present study, we investigated the potential of memantine, a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist used in the treatment of Alzheimer's disease, to mitigate the effects of ischemia-reperfusion injury in the peripheral vasculature using human umbilical cord endothelial cells (HUVECs). Previous studies have identified anti-inflammatory and antioxidant effects of memantine, but the effects of memantine on angiogenesis and microtubule formation have not been fully elucidated. Our findings indicate that pretreatment with memantine significantly reduced the expression of interleukin (IL)-6 and IL-8, which are both serum markers if AMI severity. We also demonstrate that memantine could prevent mitochondrial dysfunction and oxidative stress by rescuing mitochondrial membrane potential and reducing the production of reactive oxygen species (ROS) by NADPH oxidase-4 (NOX-4). Importantly, memantine also promoted the expression of the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) antioxidant signaling pathway. Importantly, memantine pretreatment improved cell viability and prevented the decrease in microtubule formation induced by OGD/R. Through a phosphoinositide-3-kinase (PI3K) inhibition experiment, we determined that the PI3K/protein kinase B (Akt) pathway is essential for the effects of memantine on angiogenesis. Together, our findings suggest a potential role for memantine in the prevention and treatment of AMI.

Protective effects of natural compounds against oxidative stress in ischemic diseases and cancers via activating the Nrf2 signaling pathway: A mini review

Oxidative stress, an imbalance between reactive oxygen species and antioxidants, has been seen in the pathological states of many disorders such as ischemic diseases and cancers. Many natural compounds (NCs) have long been recognized to ameliorate oxidative stress due to their inherent antioxidant activities. The modulation of oxidative stress by NCs via activating the Nrf2 signaling pathway is summarized in the review. Three NCs, ursolic acid, betulinic acid, and curcumin, and the mechanisms of their cytoprotective effects are investigated in myocardial ischemia, cerebral ischemia, skin cancer, and prostate cancer. To promote the therapeutic performance of NCs with poor water solubility, the formulation approach, such as the nano drug delivery system, is elaborated as well in this review.

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.

Curcumin targets vascular endothelial growth factor via activating the PI3K/Akt signaling pathway and improves brain hypoxic-ischemic injury in neonatal rats

This study aimed to evaluate the effect of curcumin on brain hypoxic-ischemic (HI) damage in neonatal rats and whether the phosphoinositide 3-kinase (PI3K)/Akt/vascular endothelial growth factor (VEGF) signaling pathway is involved. Brain HI damage models were established in neonatal rats, which received the following treatments: curcumin by intraperitoneal injection before injury, insulin-like growth factor 1 (IGF-1) by subcutaneous injection after injury, and VEGF by intracerebroventricular injection after injury. This was followed by neurological evaluation, hemodynamic measurements, histopathological assessment, TUNEL assay, flow cytometry, and western blotting to assess the expression of p-PI3K, PI3K, p-Akt, Akt, and VEGF. Compared with rats that underwent sham operation, rats with brain HI damage showed remarkably increased neurological deficits, reduced right blood flow volume, elevated blood viscosity and haematocrit, and aggravated cell damage and apoptosis; these injuries were significantly improved by curcumin pretreatment. Meanwhile, brain HI damage induced the overexpression of p-PI3K, p-Akt, and VEGF, while curcumin pretreatment inhibited the expression of these proteins. In addition, IGF-1 treatment rescued the curcumin-induced down-regulated expression of p-PI3K, p-Akt, and VEGF, and VEGF overexpression counteracted the inhibitory effect of curcumin on brain HI damage. Overall, pretreatment with curcumin protected against brain HI damage by targeting VEGF via the PI3K/Akt signaling pathway in neonatal rats.

Role of the neurovascular unit in the process of cerebral ischemic injury

Cerebral ischemic injury exhibits both high morbidity and mortality worldwide. Traditional research of the pathogenesis of cerebral ischemic injury has focused on separate analyses of the involved cell types. In recent years, the neurovascular unit (NVU) mechanism of cerebral ischemic injury has been proposed in modern medicine. Hence, more effective strategies for the treatment of cerebral ischemic injury may be provided through comprehensive analysis of brain cells and the extracellular matrix. However, recent studies that have investigated the function of the NVU in cerebral ischemic injury have been insufficient. In addition, the metabolism and energy conversion of the NVU depend on interactions among multiple cell types, which make it difficult to identify the unique contribution of each cell type. Therefore, in the present review, we comprehensively summarize the regulatory effects and recovery mechanisms of four major cell types (i.e., astrocytes, microglia, brain-microvascular endothelial cells, and neurons) in the NVU under cerebral ischemic injury, as well as discuss the interactions among these cell types in the NVU. Furthermore, we discuss the common signaling pathways and signaling factors that mediate cerebral ischemic injury in the NVU, which may help to provide a theoretical basis for the comprehensive elucidation of cerebral ischemic injury.

A Network Pharmacology Approach to Investigate the Active Compounds and Mechanisms of Musk for Ischemic Stroke

Objectives

This study aims to study the material basis and effective mechanism of musk for ischemic stroke (IS) based on the network pharmacology approach.

Methods

We collected the chemical components and target gene of musk from the BATMAN-TCM analytical platform and identified ischemic stroke-related targets from the following databases: DisGeNET, NCBI-Gene, HPO, OMIM, DrugBank, and TTD. The targets of musk and IS were uploaded to the String database to construct the protein-protein interaction (PPI) network, and then, the key targets were analyzed by topological methods. At last, the function biological process and signaling pathways of key targets were carried out by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis and cluster analysis by using the Database for Annotation, Visualization, and Integrated Discovery (DAVID) server and Metascape platform.

Results

A total of 29 active compounds involving 1081 predicted targets were identified in musk and there were 1104 IS-related targets. And 88 key targets of musk for IS were obtained including AKT1, MAPK1/3, TP53, TNF, SRC, FOS, CASP3, JUN, NOS3, and IL1B. The GO and KEGG enrichment analysis suggested that these key targets are mainly involved in multiple pathways which participated in TNF signaling pathway, estrogen signaling pathway, prolactin signaling pathway, neurotrophin signaling pathway, T-cell receptor signaling pathway, cAMP signaling pathway, FoxO signaling pathway, and HIF1 signaling pathway.

Conclusion

This study revealed that the effective mechanisms of musk against IS would be associated with the regulation of apoptosis, inflammatory response, and gene transcription.

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.

Hepatocellular carcinoma cell-derived extracellular vesicles encapsulated microRNA-584-5p facilitates angiogenesis through PCK1-mediated nuclear factor E2-related factor 2 signaling pathway

Hepatocellular carcinoma (HCC) is a fatal disease characterized by poor liver function with increasing morbidity and poor prognosis. Extracellular vesicles, released by different cells, have been associated with HCC development. Nevertheless, the mechanisms beyond extracellular vesicles in HCC remain uncharacterized. Therefore, the current study aimed to clarify the mechanism of pro-angiogenic microRNA-584-5p in hepatocellular carcinoma. Our results showed that miR-584-5p was highly-expressed in both cancer cells (Hep3B) and their extracellular vesicles. Hep3B and extracellular vesicles were then respectively co-cultured with human vascular endothelial cell line (Ea.hy926), and they both accelerated Ea.hy926 proliferation and migration. Ea.hy926 cells could internalize extracellular vesicles carrying microRNA-584-5p. Of note, microRNA-584-5p could bind to phosphoenolpyruvate carboxykinase 1 to promote nuclear factor E2-related factor 2. Moreover, silencing microRNA-584-5p was found to decline microvessel density, vascular endothelial growth factor A, and tumor growth in vivo and in vitro. Taken altogether, our findings demonstrated that extracellular vesicles-derived microRNA-584-5p promotes angiogenesis by inhibiting PCK1 -mediating NRF2 activation, which highlights the theoretical basis for potential treatments for HCC.

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.

VEGF signalling enhances lesion burden in KRIT1 deficient mice

The exact molecular mechanisms underlying CCM pathogenesis remain a complicated and controversial topic. Our previous work illustrated an important VEGF signalling loop in KRIT1 depleted endothelial cells. As VEGF is a major mediator of many vascular pathologies, we asked whether the increased VEGF signalling downstream of KRIT1 depletion was involved in CCM formation. Using an inducible KRIT1 endothelial‐specific knockout mouse that models CCM, we show that VEGFR2 activation plays a role in CCM pathogenesis in mice. Inhibition of VEGFR2 using a specific inhibitor, SU5416, significantly decreased the number of lesions formed and slightly lowered the average lesion size. Notably, VEGFR2 inhibition also decreased the appearance of lesion haemorrhage as denoted by the presence of free iron in adjacent tissues. The presence of free iron correlated with increased microvessel permeability in both skeletal muscle and brain, which was completely reversed by SU5416 treatment. Finally, we show that VEGFR2 activation is a common downstream consequence of KRIT1, CCM2 and CCM3 loss of function, though the mechanism by which VEGFR2 activation occurs likely varies. Thus, our study clearly shows that VEGFR2 activation downstream of KRIT1 depletion enhances the severity of CCM formation in mice, and suggests that targeting VEGF signalling may be a potential future therapy for CCM.

Downregulation of CIP2A inhibits cancer cell proliferation and vascularization in renal clear cell carcinoma

BACKGROUND

CIP2A has been proved to play a role as an oncogene in various types of malignancies while its functionality in renal clear cell carcinoma has not been investigated. Our study aimed to investigate the role of CIP2A in renal clear cell carcinoma and to explore the possible mechanisms.

METHODS

A total of 80 patients with renal clear cell carcinoma and 32 healthy people were included in the study. Expression of CIP2A was detected by qRT-PCR. CIP2A silencing renal clear cell carcinoma cell line was established. Its effects on cell proliferation and migration were verified by CCK-8 assay and Transwell cell assay, respectively. The effects of CIP2A overexpression on AKT and VEGF were investigated.

RESULTS

CIP2A expression level was increased in tumor tissues compared to adjacent healthy tissues. Serum levels of CIP2A protein were higher in cancer patients than in healthy controls, and serum levels of CIP2A protein were increased with increased stage of primary tumor. Serum CIP2A protein can be used to accurately predict renal clear cell carcinoma and its prognosis. CIP2A siRNA silencing inhibited tumor cell proliferation, and treatment with Akt activator reduced this inhibitory effect. CIP2A siRNA silencing decreased the expression level of VEGF and phosphorylation levels of AKT in renal clear cell carcinoma cells, while AKT activator treatment showed no significant effects on CIP2A expression.

CONCLUSION

Downregulation of CIP2A can inhibit cancer cell proliferation and vascularization in renal clear cell carcinoma through inactivation of the Akt pathway and its downstream VEGF.

Nrf2/ARE Pathway Modulation by Dietary Energy Regulation in Neurological Disorders

Nuclear factor erythroid 2-related factor 2 (Nrf2) regulates the expression of an array of enzymes with important detoxifying and antioxidant functions. Current findings support the role of high levels of oxidative stress in the pathogenesis of neurological disorders. Given the central role played by Nrf2 in counteracting oxidative damage, a number of studies have targeted the modulation of this transcription factor in order to confer neuroprotection. Nrf2 activity is tightly regulated by oxidative stress and energy-based stimuli. Thus, many dietary interventions based on energy intake regulation, such as dietary energy restriction (DER) or high-fat diet (HFD), modulate Nrf2 with consequences for a variety of cellular processes that affect brain health. DER, by either restricting calorie intake or meal frequency, activates Nrf2 thereby triggering its protective effects, whilst HFD inhibit this pathway, thereby exacerbating oxidative stress. Consequently, DER protocols can be valuable strategies in the management of central nervous system (CNS) disorders. Herein, we review current knowledge of the role of Nrf2 signaling in neurological diseases, namely Alzheimer’s disease, Parkinson’s disease, multiple sclerosis and cerebral ischemia, as well as the potential of energy intake regulation in the management of Nrf2 signaling.

Inhibition of the PI3K/Akt signaling pathway impedes the restoration of neurological function following hypoxic-ischemic brain damage in a neonatal rabbit model

OBJECTIVE

Hypoxic-ischemic brain damage (HIBD), frequently occurring in infancy and childhood, is a major cause of mortality and severe neurologic impairment. This study was performed to examine the effect of the PI3K/Akt signaling pathway on HIBD in a neonatal rabbit model.

MATERIALS AND METHODS

Uterine artery occlusion was used to establish HIBD models in neonatal rabbits, which were then subjected to sham operation, dimethyl sulfoxide (2 mL) or LY294002 (inhibitor of PI3K/Akt signaling pathway, 6.4 μg/kg). Behavioral neurological assessment was performed in neonatal rabbits delivered by cesarean section, after which serum neuron-specific enolase (NSE) level and cerebral water content were determined. The level of cleaved caspase-3 level and apoptosis of neurons were observed by immunohistochemistry and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining. Furthermore, the expression of PI3K/Akt signaling pathway- and apoptosis-related factors was examined.

RESULTS

In neonatal rabbits, HIBD increased the fetal death rate; reduced neurological scores of posture, righting reflex, and deglutition reflex; elevated serum NSE levels, cerebral water content, cleaved caspase-3-positive expression in hippocampal CA1 region and apoptotic neurons; inactivated PI3K/Akt signaling pathway as well as reduced Bcl-2 expression and increased BAD and Bax expression. Notably, the treatment of LY294002 further aggravated neurological impairment in neonatal rabbits in response to HIBD.

CONCLUSION

Following the HIBD caused by intrauterine asphyxia, the LY294002 administered through auricular vein infusion into pregnant rabbits exacerbates neurological impairment of neonatal rabbits, suggesting that inhibition of PI3K/Akt signaling pathway may serve as a candidate therapeutic target for neurological recovery.

To Explore the Pathogenesis of Vascular Lesion of Type 2 Diabetes Mellitus Based on the PI3K/Akt Signaling Pathway

BACKGROUND

Type 2 diabetes mellitus (T2DM) has become a chronic disease, serious harm to human health. Complications of the blood pipe are the main cause of disability and death in diabetic patients, including vascular lesions that directly affects the prognosis of patients with diabetes and survival. This study was to determine the influence of high glucose and related mechanism of vascular lesion of type 2 diabetes mellitus pathogenesis.

METHODS

In vivo aorta abdominalis of GK rats was observed with blood pressure, heart rate, hematoxylin and eosin (H&E), Masson, and Verhoeff staining. In vitro cells were cultured with 30 mM glucose for 24 h. RT-QPCR was used to detect the mRNA expression of endothelial markers PTEN, PI3K, Akt, and VEGF. Immunofluorescence staining was used to detect the expression of PTEN, PI3K, Akt, and VEGF. PI3K and Akt phosphorylation levels were detected by Western blot analysis.

RESULTS

Heart rate, systolic blood pressure, diastolic blood pressure, and mean blood pressure in the GK control group were higher compared with the Wistar control group and no difference compared with the GK experimental model group. Fluorescence intensity of VEGF, Akt, and PI3K in the high-sugar stimulus group was stronger than the control group; PTEN in the high-sugar stimulus group was weakening than the control group. VEGF, Akt, and PI3K mRNA in the high-sugar stimulus group were higher than the control group; protein expressions of VEGF, Akt, and PI3K in the high-sugar stimulus group were higher than the control group. PTEN mRNA in the high-sugar stimulus group was lower than the control group. Protein expression of PTEN in the high-sugar stimulus group was lower than the control group.

CONCLUSIONS

Angiogenesis is an important pathogenesis of T2DM vascular disease, and PTEN plays a negative regulatory role in the development of new blood vessels and can inhibit the PI3K/Akt signaling pathway.