A Bibliometric Review of the Keap1/Nrf2 Pathway and its Related Antioxidant Compounds

Sulforaphane upregulates the mRNA expression of NRF2 and NQO1 in non-dialysis patients with chronic kidney disease

Sulforaphane (SFN), found in cruciferous vegetables, is a known activator of NRF2 (master regulator of cellular antioxidant responses). Patients with chronic kidney disease (CKD) present an imbalance in the redox state, presenting reduced expression of NRF2 and increased expression of NF-κB. Therefore, this study aimed to evaluate the effects of SFN on the mRNA expression of NRF2, NF-κB and markers of oxidative stress in patients with CKD. Here, we observed a significant increase in the mRNA expression of NRF2 (p = 0.02) and NQO1 (p = 0.04) in the group that received 400 μg/day of SFN for 1 month. Furthermore, we observed an improvement in the levels of phosphate (p = 0.02), glucose (p = 0.05) and triglycerides (p = 0.02) also in this group. On the other hand, plasma levels of LDL-c (p = 0.04) and total cholesterol (p = 0.03) increased in the placebo group during the study period. In conclusion, 400 μg/day of SFN for one month improves the antioxidant system and serum glucose and phosphate levels in non-dialysis CKD patients.

Therapeutic Effect of Natural Products and Dietary Supplements on Aflatoxin-Induced Nephropathy

Aflatoxins are harmful natural contaminants found in foods and are known to be hepatotoxic. However, recent studies have linked chronic consumption of aflatoxins to nephrotoxicity in both animals and humans. Here, we conducted a systematic review of active compounds, crude extracts, herbal formulations, and probiotics against aflatoxin-induced renal dysfunction, highlighting their mechanisms of action in both in vitro and in vivo studies. The natural products and dietary supplements discussed in this study alleviated aflatoxin-induced renal oxidative stress, inflammation, tissue damage, and markers of renal function, mostly in animal models. Therefore, the information provided in this review may improve the management of kidney disease associated with aflatoxin exposure and potentially aid in animal feed supplementation. However, future research is warranted to translate the outcomes of this study into clinical use in kidney patients.

Sulforaphane Supplementation Did Not Modulate NRF2 and NF-kB mRNA Expressions in Hemodialysis Patients

BACKGROUND

Patients with chronic kidney disease (CKD) have reduced expression of erythroid nuclear factor-related factor 2 (NRF2) and increased nuclear factor κB (NF-κB). "Food as medicine" has been proposed as an adjuvant therapeutic alternative in modulating these factors. No studies have investigated the effects of sulforaphane (SFN) in cruciferous vegetables on the expression of these genes in patients with CKD.

OBJECTIVE

The study aimed to evaluate the effects of SFN on the expression of NRF2 and NF-κB in patients on hemodialysis (HD).

DESIGN AND METHODS

A randomized, double-blind, crossover study was performed on 30 patients on regular HD. Fourteen patients were randomly allocated to the intervention group (1 sachet/day of 2.5 g containing 1% SFN extract with 0.5% myrosinase) and 16 patients to the placebo group (1 sachet/day of 2.5 g containing corn starch colored with chlorophyll) for 2 months. After a washout period of 2 months, the groups were switched. NRF2 and NF-κB mRNA expression was evaluated by real-time quantitative polymerase chain reaction, and tumor necrosis factor alpha and interleukin-6 levels were quantified by enzyme-linked immunosorbent assay. Malondialdehyde was evaluated as a marker of lipid peroxidation.

RESULTS

Twenty-five patients (17 women, 55 [interquartile range = 19] years and 55 [interquartile range = 74] months on HD) completed the study. There was no significant difference concerning the expression of mRNA NRF2 (P = .915) and mRNA NF-κB (P = .806) after supplementation with SFN. There was no difference in pro-inflammatory and oxidative stress biomarkers.

CONCLUSION

150 μmol of SFN for 2 months had no antioxidant and anti-inflammatory effect in patients with CKD undergoing HD.

Treatment-prognostication-adjustment a new therapeutic idea by analyzing T cell immune checkpoint in tumor microenvironment by algorithm: A bibliometric analysis

To evaluate the temporal and spatial distribution of the knowledge network about tumor microenvironment and prognoses and explore new research hot spots and trends. Articles and reviews on tumor microenvironment and prognoses in the Web of Science journal from January 1999 to April 2022 were included. We used the CiteSpace and VOSviewer software to analyze the knowledge network composed of journals, institutions, countries, authors, and keywords. Frontiers in Immunology, Cancers, and Frontiers in Oncology have published more than 10% of articles in this field. China and the United States have contributed the most articles. Fudan University and Sun Yat-Sen University are the most active institutions. The authors in this field work closely; Zhang Wei and Douglas have made outstanding contributions. The three main research areas of tumor microenvironment and prognoses are microenvironment, prognosis, and immunotherapy. Until 2020, the main keywords were endothelial growth factor and adhesion. In the past three years, survival analysis, immune cell infiltration, and prediction model have been used. It can be seen that the focus in this field has shifted from tumor cell behavior and directly related molecules to prognosis prediction and non-tumor cells in the microenvironment. The future research trend may be to study the changes in the tumor microenvironment to predict the prognosis and guide the treatment. VOSviewer, CiteSpace, and Microsoft Excel 2019 were used to conduct a comprehensive visual analysis of the research on tumor environment and prognoses and provide valuable reference materials for researchers.

Ferulic acid exerts a protective effect against cyclosporine-induced liver injury in rats via activation of the Nrf2/HO-1 signaling, suppression of oxidative stress, inflammatory response, and halting the apoptotic cell death

Drug-induced liver injury is one of the main challenges that leads to the withdrawal of several drugs in the clinical setting. Cyclosporine is one of the drugs that its long-term administration exerts devastating effects on the hepatocytes. In the present study, we aimed to evaluate the effect of ferulic acid, a natural compound found in plants, on cyclosporine-mediated hepatotoxicity. Forty-eight male Wistar rats were treated with cyclosporine and/or ferulic acid to evaluate the function as well as the morphology of liver cells. We found that ferulic acid dose-dependently recovered the functional as well as histopathological parameters of liver cells, as revealed by the improvement of hepatocellular vacuolation, portal fibroplasia, and necrosis. Moreover, this phenolic compound was able to restore the balance of the redox system in cyclosporine-treated rats by activating the nuclear factor (NF) erythroid 2-related factor 2 (Nrf2)/hemeoxygenase-1 (HO-1) signaling axis. Of note, the protective effects of ferulic acid against cyclosporine-mediated liver toxicity were not restricted only to induction of the potential antioxidant property, as in the presence of this agent, the expression of pro-inflammatory cytokines such as NF-κB, tumor necrosis factor (TNF)-α, and interleukin-1β was also diminished. Ferulic acid also shifted the equilibrium between the expression levels of proapoptotic to antiapoptotic proteins and thereby prevented the development of cyclosporine-induced liver injury. Overall, these findings highlighted that ferulic acid can reduce cyclosporine-induced liver injury due to its antioxidant properties.

A worldwide bibliometric analysis of acromegaly in the past two decades: 1999-2022

Objectives

To conduct a bibliometric analysis to quantify and identify the current status and trends of acromegaly research in the past two decades.

Materials and methods

Articles related to acromegaly that were published from 1999 to 2022 were retrieved through the Web of Science core collection (WoSCC) database. Then, they were imported into VOSviewer and CiteSpace to conduct a visualization analysis of authors, countries, institutions, citation numbers, cocitations, keywords, and references.

Results

A total of 3,909 articles were identified in the study. Among them, the United States made the largest contribution to the field. Moreover, Colao A. was the most prolific author, and the University of Naples Federico II was the institution with the most publications. In addition, the Journal of Clinical Endocrinology and Metabolism was the core journal in the field. High-frequency keywords mainly included "acromegaly," "GH (Growth Hormone)," "IGH-I (Insulin-Like Growth Factor I)," "pituitary adenomas," and "octreotide."

Conclusion

Studies related to acromegaly have shown stable stepwise growth over the past two decades. Interestingly, the research focus after 2016 gradually shifted from the etiology, mechanism, medications for treatment, and complications to improving prognosis and quality of life of patients with acromegaly. The current findings may provide guidance for further research in the field of acromegaly.

CRISPR/Cas9-Based Screening of FDA-Approved Drugs for NRF2 Activation: A Novel Approach to Discover Therapeutics for Non-Alcoholic Fatty Liver Disease

With the rising prevalence of obesity, non-alcoholic fatty liver disease (NAFLD) now affects 20-25% of the global population. NAFLD, a progressive condition associated with oxidative stress, can result in cirrhosis and liver cancer in 10% and 3% of patients suffering NAFLD, respectively. Therapeutic options are currently limited, emphasizing the need for novel treatments. In this study, we examined the potential of activating the transcription factor NRF2, a crucial player in combating oxidative stress, as an innovative approach to treating NAFLD. Utilizing a CRISPR/Cas9-engineered human HEK293T cell line, we were able to monitor the expression of heme oxygenase-1 (HMOX1), an NRF2 target, using a Nanoluc luciferase tag. Our model was validated using a known NRF2 activator, after which we screened 1200 FDA-approved drugs, unearthing six compounds (Disulfiram, Thiostrepton, Auranofin, Thimerosal, Halofantrine, and Vorinostat) that enhanced NRF2 activity and antioxidant response. These compounds demonstrated protective effects against oxidative stress induced by hydrogen peroxide and lipid droplets accumulation in vitro with hepatoma HUH-7 cells. Our study underscores the utility of CRISPR/Cas9 tagging with Nanoluc luciferase in identifying potential NRF2 activators, paving the way for potential NAFLD therapeutics.

Cannabidiol as a Promising Therapeutic Option in IC/BPS: In Vitro Evaluation of Its Protective Effects against Inflammation and Oxidative Stress

Several animal studies have described the potential effect of cannabidiol (CBD) in alleviating the symptoms of interstitial cystitis/bladder pain syndrome (IC/BPS), a chronic inflammatory disease of the urinary bladder. However, the effects of CBD, its mechanism of action, and modulation of downstream signaling pathways in urothelial cells, the main effector cells in IC/BPS, have not been fully elucidated yet. Here, we investigated the effect of CBD against inflammation and oxidative stress in an in vitro model of IC/BPS comprised of TNFα-stimulated human urothelial cells SV-HUC1. Our results show that CBD treatment of urothelial cells significantly decreased TNFα-upregulated mRNA and protein expression of IL1α, IL8, CXCL1, and CXCL10, as well as attenuated NFκB phosphorylation. In addition, CBD treatment also diminished TNFα-driven cellular reactive oxygen species generation (ROS), by increasing the expression of the redox-sensitive transcription factor Nrf2, the antioxidant enzymes superoxide dismutase 1 and 2, and hem oxygenase 1. CBD-mediated effects in urothelial cells may occur by the activation of the PPARγ receptor since inhibition of PPARγ resulted in significantly diminished anti-inflammatory and antioxidant effects of CBD. Our observations provide new insights into the therapeutic potential of CBD through modulation of PPARγ/Nrf2/NFκB signaling pathways, which could be further exploited in the treatment of IC/BPS.

Cannabidiol: Bridge between Antioxidant Effect, Cellular Protection, and Cognitive and Physical Performance

The literature provides scientific evidence for the beneficial effects of cannabidiol (CBD), and these effects extend beyond epilepsy treatment (e.g., Lennox-Gastaut and Dravet syndromes), notably the influence on oxidative status, neurodegeneration, cellular protection, cognitive function, and physical performance. However, products containing CBD are not allowed to be marketed everywhere in the world, which may ultimately have a negative effect on health as a result of the uncontrolled CBD market. After the isolation of CBD follows the discovery of CB1 and CB2 receptors and the main enzymatic components (diacylglycerol lipase (DAG lipase), monoacyl glycerol lipase (MAGL), fatty acid amino hydrolase (FAAH)). At the same time, the antioxidant potential of CBD is due not only to the molecular structure but also to the fact that this compound increases the expression of the main endogenous antioxidant systems, superoxide dismutase (SOD), and glutathione peroxidase (GPx), through the nuclear complex erythroid 2-related factor (Nrf2)/Keep1. Regarding the role in the control of inflammation, this function is exercised by inhibiting (nuclear factor kappa B) NF-κB, and also the genes that encode the expression of molecules with a pro-inflammatory role (cytokines and metalloproteinases). The other effects of CBD on cognitive function and physical performance should not be excluded. In conclusion, the CBD market needs to be regulated more thoroughly, given the previously listed properties, with the mention that the safety profile is a very good one.

Natural Products as Modulators of Nrf2 Signaling Pathway in Neuroprotection

Neurodegenerative diseases (NDs) affect the West due to the increase in life expectancy. Nervous cells accumulate oxidative damage, which is one of the factors that triggers and accelerates neurodegeneration. However, cells have mechanisms that scavenge reactive oxygen species (ROS) and alleviate oxidative stress (OS). Many of these endogenous antioxidant systems are regulated at the gene expression level by the transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2). In the presence of prooxidant conditions, Nrf2 translocates to the nucleus and induces the transcription of genes containing ARE (antioxidant response element). In recent years, there has been an increase in the study of the Nrf2 pathway and the natural products that positively regulate it to reduce oxidative damage to the nervous system, both in in vitro models with neurons and microglia subjected to stress factors and in vivo models using mainly murine models. Quercetin, curcumin, anthocyanins, tea polyphenols, and other less studied phenolic compounds such as kaempferol, hesperetin, and icariin can also modulate Nrf2 by regulating several Nrf2 upstream activators. Another group of phytochemical compounds that upregulate this pathway are terpenoids, including monoterpenes (aucubin, catapol), diterpenes (ginkgolides), triterpenes (ginsenosides), and carotenoids (astaxanthin, lycopene). This review aims to update the knowledge on the influence of secondary metabolites of health interest on the activation of the Nrf2 pathway and their potential as treatments for NDs.

Ferroptosis synergistically sensitizes wee1 inhibitors: a bibliometric study

Synthetic lethality (SL) is a lethal phenomenon with an important role in cancer treatment. This study was conducted to analyze the hotspots and frontiers in SL research. The Web of Science Core Collection (WOSCC) was used to identify the 100 top-cited articles related to SL research. Additionally, wee1 inhibitors combined with erastin were used to determine the effectiveness of SL in vitro and in vivo. Relevant articles were published mainly from 2009 to 2021, reaching a peak in 2020; articles published in 2010 were most frequently cited among the 100-top cited papers. Most studies (54%) were performed in the United States. Articles in Nature Chemical Biology were cited more frequently than articles in other journals, whereas Nature published the largest number of reports on SL. Among the 88 corresponding authors, CJ Lord was the most productive. Overlay visualization of keyword analysis revealed that the hotspots in SL research were PARP inhibitors, BRCA mutations, DNA damage repair, and carcinogenesis. CRISPR, ferroptosis, wee1, double-strand break (dsb) repair, myc, immunotherapy, and replication stress are emerging topics in SL research, whereas ovarian cancer, prostate stress, acute myeloid leukemia, and other topics have been used as disease models in recent years. The application and therapeutic strategy of SL in cancer is an emerging trend. Significantly, experiments verified that the wee1 inhibitor AZD1775 and ferroptosis activator erastin have synergistic effects on ovarian cancer in vitro and in vivo. Combining bibliometric analysis with experimental verification is a useful approach for SL research.

Knowledge mapping of alternative splicing of cancer from 2012 to 2021: A bibliometric analysis

Background

As a processing method of RNA precursors, alternative splicing (AS) is critical to normal cellular activities. Aberrant AS events are associated with cancer development and can be promising targets to treat cancer. However, no detailed and unbiased study describes the current state of AS of cancer research. We aim to measure and recognize the current state and trends of AS cancer research in this study.

Methods

The Web of Science Core Collection was used to acquire the articles. Utilizing three bibliometric tools (CiteSpace, VOSviewer, R-bibliometrix), we were able to measure and recognize the influence and collaboration data of individual articles, journals, and co-citations. Analysis of co-occurrence and burst information helped us identify the trending research areas related to AS of cancer.

Results

From 2012 to 2021, the total number of papers on AS of cancer published in 766 academic journals was 3,507, authored by 20,406 researchers in 405 institutions from 80 countries/regions. Research involving AS of cancer genes was primarily conducted in the United States and China; simultaneously, the Chinese Academy of Sciences, Fudan University, and National Cancer Institute were the institutions with strong research capabilities. Scorilas Andreas is the scholar with the most publications, while the most co-citations were generated by Wang, Eric T. Plos One published the most papers on AS of cancer, while J Biol Chem was the most co-cited academic journal in this field. The results of keyword co-occurrence analysis can be divided into three types: molecular (P53, CD44, androgen receptor, srsf3, esrp1), pathological process (apoptosis, EMT, metastasis, angiogenesis, proliferation), and disease (breast cancer, colorectal cancer, prostate cancer, hepatocellular carcinoma, gastric cancer).

Conclusion

Research on AS of cancer has been increasing in intensity over the past decade. Current AS of cancer studies focused on the hallmarks of AS in cancer and AS signatures including diagnostic and therapeutic targets. Among them, the current trends are splicing factors regulating epithelial-mesenchymal transition and other hallmarks, aberrant splicing events in tumors, and further mechanisms. These might give researchers interested in this field a forward-looking perspective and inform further research.

DHPA Protects SH-SY5Y Cells from Oxidative Stress-Induced Apoptosis via Mitochondria Apoptosis and the Keap1/Nrf2/HO-1 Signaling Pathway

Oxidative stress in the brain is highly related to the pathogenesis of Alzheimer’s disease (AD). It could be induced by the overproduction of reactive oxygen species (ROS), produced by the amyloid beta (Aβ) peptide and excess copper (Cu) in senile plaques and cellular species, such as ascorbic acid (AA) and O₂. In this study, the protective effect of 5-hydroxy-7-(4′-hydroxy-3′-methoxyphenyl)-1-phenyl-3-heptanone (DHPA) on Aβ_(1–42)/Cu²⁺/AA mixture-treated SH-SY5Y cells was investigated via in vitro and in silico studies. The results showed that DHPA could inhibit Aβ/Cu²⁺/AA-induced SH-SY5Y apoptosis, OH· production, intracellular ROS accumulation, and malondialdehyde (MDA) production. Further research demonstrated that DHPA could decrease the ratio of Bax/Bcl-2 and repress the increase of mitochondrial membrane potential (MMP) of SH-SY5Y cells, to further suppress the activation of caspase-3, and inhibit cell apoptosis. Meanwhile, DHPA could inhibit the Aβ/Cu²⁺/AA-induced phosphorylation of Erk1/2 and P38 in SH-SY5Y cells, and increase the expression of P-AKT. Furthermore, DHPA could bind to Keap1 to promote the separation of Nrf2 to Keap1 and activate the Keap1/Nrf2/HO-1 signaling pathway to increase the expression of heme oxygenase-1 (HO-1), quinone oxidoreductase-1 (NQO1), glutathione (GSH), and superoxide dismutase (SOD). Thus, our results demonstrated that DHPA could inhibit Aβ/Cu²⁺/AA-induced SH-SY5Y apoptosis via scavenging OH·, inhibit mitochondria apoptosis, and activate the Keap1/Nrf2/HO-1 signaling pathway.

Oxidative Stress and NRF2/KEAP1/ARE Pathway in Diabetic Kidney Disease (DKD): New Perspectives

Diabetes mellitus (DM) is one of the most debilitating chronic diseases worldwide, with increased prevalence and incidence. In addition to its macrovascular damage, through its microvascular complications, such as Diabetic Kidney Disease (DKD), DM further compounds the quality of life of these patients. Considering DKD is the main cause of end-stage renal disease (ESRD) in developed countries, extensive research is currently investigating the matrix of DKD pathophysiology. Hyperglycemia, inflammation and oxidative stress (OS) are the main mechanisms behind this disease. By generating pro-inflammatory factors (e.g., IL-1,6,18, TNF-α, TGF-β, NF-κB, MCP-1, VCAM-1, ICAM-1) and the activation of diverse pathways (e.g., PKC, ROCK, AGE/RAGE, JAK-STAT), they promote a pro-oxidant state with impairment of the antioxidant system (NRF2/KEAP1/ARE pathway) and, finally, alterations in the renal filtration unit. Hitherto, a wide spectrum of pre-clinical and clinical studies shows the beneficial use of NRF2-inducing strategies, such as NRF2 activators (e.g., Bardoxolone methyl, Curcumin, Sulforaphane and their analogues), and other natural compounds with antioxidant properties in DKD treatment. However, limitations regarding the lack of larger clinical trials, solubility or delivery hamper their implementation for clinical use. Therefore, in this review, we will discuss DKD mechanisms, especially oxidative stress (OS) and NRF2/KEAP1/ARE involvement, while highlighting the potential of therapeutic approaches that target DKD via OS.

Proanthocyanidins Activate Nrf2/ARE Signaling Pathway in Intestinal Epithelial Cells by Inhibiting the Ubiquitinated Degradation of Nrf2

Nrf2 plays a key role in the antioxidant system, and many antioxidants can activate the Nrf2/ARE signaling pathway and alleviate oxidative stress. However, the underlying mechanisms of antioxidants, such as proanthocyanidin- (PC-) induced Nrf2 activation, remain poorly understood. In this study, PC was used on MODE-K cells at different concentrations (0, 1, 2.5, and 5 μg/mL) and different times (0, 3, 6, 12, and 24 h); then, immunoprecipitation, immunofluorescence, and Western blotting were performed to test Nrf2, Bach1, Keap1, HO-1, and NQO1 protein expressions in MODE-K cells. Results showed that PC increased Nrf2, HO-1, and NQO1 protein expressions, decreased Keap1 and Bach1 protein expressions, and enhanced ARE gene activity. PC also decreased the ubiquitinated degradation of the Nrf2 protein, increased Nrf2 protein stability, and increased Nrf2 protein expression by inhibiting Keap1-dependent Nrf2 protein degradation, promoted Nrf2 entry into the nucleus, competed with Bach1, and activated ARE elements, which in turn initiated the Nrf2/ARE signaling pathway. Thus, we conclude that PC activates the Nrf2/ARE signaling pathway in intestinal epithelial cells by inhibiting the ubiquitinated degradation of Nrf2, increasing Nrf2 protein stability and expression, and then regulating key antioxidant enzymes such as HO-1 and NQO1 to initiate cytoprotective effects.

The Tower of Babel of Pharma-Food Study on Extra Virgin Olive Oil Polyphenols

Much research has been conducted to reveal the functional properties of extra virgin olive oil polyphenols on human health once EVOO is consumed regularly as part of a balanced diet, as in the Mediterranean lifestyle. Despite the huge variety of research conducted, only one effect of EVOO polyphenols has been formally approved by EFSA as a health claim. This is probably because EFSA’s scientific opinion is entrusted to scientific expertise about food and medical sciences, which adopt very different investigative methods and experimental languages, generating a gap in the scientific communication that is essential for the enhancement of the potentially useful effects of EVOO polyphenols on health. Through the model of the Tower of Babel, we propose a challenge for science communication, capable of disrupting the barriers between different scientific areas and building bridges through transparent data analysis from the different investigative methodologies at each stage of health benefits assessment. The goal of this work is the strategic, distinctive, and cost-effective integration of interdisciplinary experiences and technologies into a highly harmonious workflow, organized to build a factual understanding that translates, because of trade, into health benefits for buyers, promoting EVOOs as having certified health benefits, not just as condiments.

Knowledge Mapping of Necroptosis From 2012 to 2021: A Bibliometric Analysis

Background

Necroptosis, a recently discovered programmed cell death, has been pathologically linked to various diseases and is thus a promising target for treating diseases. However, a comprehensive and objective report on the current status of entire necroptosis research is lacking. Therefore, this study aims to conduct a bibliometric analysis to quantify and identify the status quo and trending issues of necroptosis research in the last decade.

Methods

Articles were acquired from the Web of Science Core Collection database. We used two bibliometric tools (CiteSpace and VOSviewer) to quantify and identify the individual impact and cooperation information by analyzing annual publications, journals, co-cited journals, countries/regions, institutions, authors, and co-cited authors. Afterwards, we identified the trending research areas of necroptosis by analyzing the co-occurrence and burst of keywords and co-cited references.

Results

From 2012 to 2021, a total of 3,111 research articles on necroptosis were published in 786 academic journals by 19,687 authors in 885 institutions from 82 countries/regions. The majority of publications were from China and the United States, of which the United States maintained the dominant position in necroptosis research; meanwhile, the Chinese Academy of Sciences and Ghent University were the most active institutions. Peter Vandenabeele published the most papers, while Alexei Degterev had the most co-citations. Cell Death & Disease published the most papers on necroptosis, while Cell was the top 1 co-cited journal, and the major area of these publications was molecular, biology, and immunology. High-frequency keywords mainly included those that are molecularly related (MLKL, TNF-alpha, NF-κB, RIPK3, RIPK1), pathological process related (cell-death, apoptosis, necroptosis, necrosis, inflammation), and disease related (cancer, ischemia/reperfusion injury, infection, carcinoma, Alzheimer’s disease).

Conclusion

Necroptosis research had a stable stepwise growth in the past decade. Current necroptosis studies focused on its cross-talk with other types of cell death, potential applications in disease treatment, and further mechanisms. Among them, the synergy with ferroptosis, further RIPK1/RIPK3/MLKL studies, its association with inflammation and oxidative stress and translational applications, and the therapeutic potential to treat cancer and neurodegenerative diseases are the trending research area. These might provide ideas for further research in the necroptosis field.

Kahweol Protects against Acetaminophen-Induced Hepatotoxicity in Mice through Inhibiting Oxidative Stress, Hepatocyte Death, and Inflammation

Acetaminophen (APAP) can cause acute liver failure, but treatment options are still limited. Kahweol is the main diterpene compound of coffee and possesses antioxidant and anti-inflammatory properties. Emerging evidence suggests that this natural diterpene exerts favorable effects on several inflammatory diseases. However, the action of kahweol on APAP toxicity has not been addressed. The purpose of this study was to explore whether kahweol has a protective activity against APAP-induced hepatotoxicity and to investigate the mechanism. Administration of kahweol reduced serum levels of liver injury indicators and ameliorated histological abnormalities in APAP-treated mice. Kahweol inhibited lipid peroxidation and nucleic acid oxidation with restoration of glutathione content and stimulation of nuclear factor erythroid-2-related factor 2-dependent cellular defense system. Hepatocyte death was also decreased by kahweol, which was associated with inhibition of endoplasmic reticulum (ER) stress. Moreover, kahweol reduced hepatic levels of inflammatory mediators, inhibited nuclear factor-κB activation, and attenuated infiltration of neutrophils and macrophages. These findings suggest that kahweol has a protective activity against APAP-induced liver injury and this effect is related to the suppression of oxidative stress, hepatocyte death, ER stress, and inflammation.

Anti-neuroinflammatory activity of 6,7-dihydroxy-2,4-dimethoxy phenanthrene isolated from Dioscorea batatas Decne partly through suppressing the p38 MAPK/NF-κB pathway in BV2 microglial cells

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizome of Dioscorea batatas Decne (called Chinses yam) widely distributed in East Asian countries including China, Japan, Korea and Taiwan has long been used in oriental folk medicine owing to its tonic, antitussive, expectorant and anti-ulcerative effects. It has been reported to have anti-inflammatory, antioxidative, cholesterol-lowering, anticholinesterase, growth hormone-releasing, antifungal and immune cell-stimulating activities.

AIM OF THE STUDY

Neuroinflammation caused by activated microglia contributes to neuronal dysfunction and neurodegeneration. In the present study, the anti-neuroinflammatory activity of 6,7-dihydroxy-2,4-dimethoxy phenanthrene (DHDMP), a phenanthrene compound isolated from Dioscorea batatas Decne, was examined in microglial and neuronal cells.

MATERIALS AND METHODS

A natural phenanthrene compound, DHDMP, was isolated from the peel of Dioscorea batatas Decne. The anti-neuroinflammatory capability of the compound was examined using the co-culture system of BV2 murine microglial and HT22 murine neuronal cell lines. The expression levels of inflammatory mediators and cytoprotective proteins in the cells were quantified by enzyme-linked immunosorbent assay and Western blot analysis.

RESULTS

DHDMP at the concentrations of ≤1 μg/mL did not exhibit a cytotoxic effect for BV2 and HT22 cells. Rather DHDMP effectively restored the growth rate of HT22 cells, which was reduced by co-culture with lipopolysaccharide (LPS)-treated BV2 cells. DHDMP significantly decreased the production of proinflammatory mediators, such as nitric oxide, tumor necrosis factor-α, interleukin-6, inducible nitric oxide synthase, and cyclooxygenase-2 in BV2 cells. Moreover, DHDMP strongly inhibited the nuclear translocation of nuclear factor κB (NF-κB) and phosphorylation of p38 mitogen-activated protein kinase (MAPK) in BV2 cells. The compound did not affect the levels and phosphorylation of ERK and JNK. Concurrently, DHDMP increased the expression of heme oxygenase-1 (HO-1), an inducible cytoprotective enzyme, in HT22 cells.

CONCLUSIONS

Our findings indicate that DHDMP effectively dampened LPS-mediated inflammatory responses in BV2 microglial cells by suppressing transcriptional activity of NF-κB and its downstream mediators and contributed to HT22 neuronal cell survival. This study provides insight into the therapeutic potential of DHDMP for inflammation-related neurological diseases.

WD-40 repeat protein 26 protects against oxidative stress-induced injury in astrocytes via Nrf2/HO-1 pathways

BACKGROUND

Stroke is the leading cause of disability and the third leading cause of death in the world, and no effective treatment has been developed. Oxidative stress-induced cell injury and genomic instability is implicated in the pathogenesis of stroke, whose prognosis remains poor.

METHODS

A model of cerebral ischemic/reperfusion injury model was established through four artery occlusions. This study was carried out using western blot, flow cytometry and RT-PCR on cell line U251-MG. The cytotoxic effect of H₂O₂ and expression of LDH, caspase-3, MDA and SOD was analyzed by assay kit.

RESULTS

We found that the expression of WDR26 was induced in cerebral ischemia-reperfusion injury in vivo and the expression of WDR26 was induced by H₂O₂ in a dose- and time-dependent manner in vitro. WDR26 over-expression significantly suppressed H₂O₂-induced cell death and caspase-3-mediated apoptosis in U251-MG cells. In contrast, inhibition of WDR26 markedly enhanced cell death in U251-MG cells. In addition, WDR26 regulated oxidative stress response and induced Nrf2/HO-1 pathway.

CONCLUSIONS

These findings suggest that WDR26 mediates H₂O₂-induced oxidative stress and cell injury, possibly by reducing the intrinsic apoptotic pathway and activating Nrf2 and HO-1 in astrocytes.

Hotspots and trends in liver kinase B1 research: A bibliometric analysis

Introduction

In the past 22 years, a large number of publications have reported that liver kinase B1 (LKB1) can regulate a variety of cellular processes and play an important role in many diseases. However, there is no systematic bibliometric analysis on the publications of LKB1 to reveal the research hotspots and future direction.

Methods

Publications were retrieved from the Web of Science Core Collection (WoSCC), Scopus, and PubMed databases. CiteSpace and VOSviewer were used to analysis the top countries, institutions, authors, source journals, discipline categories, references, and keywords.

Results

In the past 22 years, the number of LKB1 publications has increased gradually by year. The country, institution, author, journals that have published the most articles and cited the most frequently were the United States, Harvard University, Prof. Benoit Viollet, Journal of Biochemistry and Plos One. The focused research hotspot was the molecular functions of LKB1. The emerging hotspots and future trends are the clinical studies about LKB1 and co-mutated genes as biomarkers in tumors, especially in lung adenocarcinoma.

Conclusions

Our research could provide knowledge base, frontiers, emerging hotspots and future trends associated with LKB1 for researchers in this field, and contribute to finding potential cooperation possibilities.

Effects of chitooligosaccharide-zinc on the ovarian function of mice with premature ovarian failure via the SESN2/NRF2 signaling pathway

Chitooligosaccharide-zinc (COS·Zn) is a powerful anti-oxidant and anti-aging scavenger, whose anti-oxidative ability immensely exceeds vitamin C. Therefore, this study was aimed to investigate the protective effects of COS·Zn against premature ovarian failure (POF) and potential mechanisms. Female KM adult mice were divided into the following groups: a treatment group (150 mg·kg^-1·d^-1 COS·Zn), a treatment group (300 mg·kg^-1·d^-1 COS·Zn), a prevention group, two control groups and two CY/BUS groups. COS·Zn (150, 300 mg·kg^-1·d^-1) and COS·Zn (300 mg·kg^-1·d^-1) were therapeutically and preventatively administered to POF mice in the treatment and prevention studies, respectively. All the groups were administered for 21 days. Fewer primary and secondary follicles were observed in the COS·Zn-treated groups (including the treatment and prevention groups) than those of the control groups. Meanwhile, the ovarian index and the levels of FSH and LH notably increased in the treatment and prevention groups compared with those in the CY/BUS group. The levels of MVH, OCT4 and PCNA in the treatment group (300·kg^-1·d^-1 COS·Zn) and MVH in the prevention group remarkably increased compared with those in the CY/BUS groups. Meanwhile, the levels of P53 and P16 protein were down-regulated in the treatment and prevention groups compared with those in the CY/BUS groups. Additionally, the amounts of Sestrin2 (SESN2) and SOD2 protein were obviously higher in the treatment group (150 mg·kg^-1·d^-1 COS·Zn) than those in the CY/BUS groups. Similarly, the amounts of NRF2 and SESN2 protein were up-regulated in the prevention group. Besides, an increased GSH level was observed in the two treatment groups, compared with that in the CY/BUS groups, and the same trend was also present in the prevention group. Taken together, COS·Zn improves the ovarian and follicular development through regulating the SESN2/NRF2 signaling pathway. These results suggest the role of COS·Zn as a novel agent for the treatment and prevention of POF.

Mathematical modeling reveals quantitative properties of KEAP1-NRF2 signaling

Under oxidative and electrophilic stresses, cells launch an NRF2-mediated transcriptional antioxidant program. The activation of NRF2 depends on a redox sensor, KEAP1, which promotes the ubiquitination and degradation of NRF2. While a great deal has been learned about this duo, its quantitative signaling properties are largely unexplored. Here we examined these properties, including half-life, maximal activation, and response steepness (ultrasensitivity) of NRF2, through mathematical modeling. The models describe the binding of KEAP1 and NRF2 via ETGE and DLG motifs, NRF2 production, KEAP1-dependent and independent NRF2 degradation, and perturbations by different classes of NRF2 activators. Simulations revealed at the basal condition, NRF2 is sequestered by KEAP1 and the KEAP1-NRF2 complex is distributed comparably in an ETGE-bound (open) state and an ETGE and DLG dual-bound (closed) state. When two-step ETGE binding is considered, class I–V, electrophilic NRF2 activators shift the balance to a closed state incompetent to degrade NRF2, while the open and closed KEAP1-NRF2 complexes transition from operating in cycle mode to equilibrium mode. Ultrasensitive NRF2 activation (a steep rise of free NRF2) can occur when NRF2 nearly saturates KEAP1. The ultrasensitivity results from zero-order degradation through DLG binding and protein sequestration through ETGE binding. Optimal abundances of cytosolic and nuclear KEAP1 exist to maximize ultrasensitivity. These response characteristics do not require disruption of DLG binding as suggested by the hinge-latch hypothesis. In comparison, class VI NRF2 activators cause a shift to the open KEAP1-NRF2 complex and ultimately its complete dissociation, resulting in a fast release of NRF2 followed by stabilization. However, ultrasensitivity is lost due to decreasing free KEAP1 abundance. In summary, by simulating the dual role of KEAP1, i.e., sequestering and promoting degradation of NRF2, our modeling provides novel quantitative insights into NRF2 activation, which may help design novel NRF2 modulators and understand the oxidative actions of environmental stressors.

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Steep (ultrasensitive) NRF2 activation can occur when it rises to saturate KEAP1.

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Ultrasensitivity results from zero-order degradation and protein sequestration.

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Optimal cytosolic and nuclear KEAP1 abundances exist for maximal ultrasensitivity.

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Open and closed KEAP1-NRF2 complexes transition in cycle and equilibrium mode.

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NRF2 activation by KEAP1-NRF2 interaction inhibitors is more gradual.

Silymarin (milk thistle extract) as a therapeutic agent in gastrointestinal cancer

Silymarin contains a group of closely-related flavonolignan compounds including silibinin, and is extracted from Silybum marianum species, also called milk thistle. Silymarin has been shown to protect the liver in both experimental models and clinical studies. The chemopreventive activity of silymarin has shown some efficacy against cancer both in vitro and in vivo. Silymarin can modulate apoptosis in vitro and survival in vivo, by interfering with the expression of cell cycle regulators and apoptosis-associated proteins. In addition to its anti-metastatic activity, silymarin has also been reported to exhibit anti-inflammatory activity. The chemoprotective effects of silymarin and silibinin (its major constituent) suggest they could be applied to reduce the side effects and increase the anti-cancer effects of chemotherapy and radiotherapy in various cancer types, especially in gastrointestinal cancers. This review examines the recent studies and summarizes the mechanistic pathways and down-stream targets of silymarin in the therapy of gastrointestinal cancer.

A bibliometric analysis of Wnt signaling pathway: from the top-100 cited articles to emerging trends

Background

Wnt signaling pathway plays a vital role in the regulation of development. An increasing number of articles about Wnt pathway components have been published. By analyzing these studies’ characteristics and qualities, we aim to reveal the current research focus and emerging trends in Wnt signaling.

Methods

The databases of Web of Science Core Collection, BIOSIS Citation Index, MEDLINE, etc. were utilized to identify articles on May 23rd, 2020. Wnt signaling pathway-related articles were identified, the 100 most cited articles and articles in the last decade were selected and calculated for citations without self-citation. The subsequent analysis included citation density (citations/article age), time-related flux, authorship, institution, journal, geographic distribution, and theme.

Results

These articles were published mainly from 2000 to 2009 (62%). Citations per article ranged from 599 to 3,780 with a median number of 880 times. Most studies (66%) came from the United States. Nusse Roel and Clevers Hans (15 and 13 papers) have contributed significantly to the field. The most highlighted study themes were cancer (15%), embryo development (14%), and cytoplasm signal transduction (11%). From 2011 to 2020, interest in emerging subtopics, including osteogenesis, immune, apoptosis, autophagy, microRNA, and cancer stem cell, are rising.

Conclusions

Cancer, embryo development, stem cell, and signal transduction process still play a major role in the field. With multiple emerging subtopics and investigation on an integrated view of the Wnt signal network, the association of Wnt with diseases was further revealed.

MicroRNAs Involved in Oxidative Stress Processes Regulating Physiological and Pathological Responses

Oxidative stress influences several physiological and pathological cellular events, including cell differentiation, excessive growth, proliferation, apoptosis, and the inflammatory response. Therefore, oxidative stress is involved in the pathogenesis of various diseases, including pulmonary fibrosis, epilepsy, hypertension, atherosclerosis, Parkinson's disease, cardiovascular disease, and Alzheimer's disease. Recent studies have shown that several microRNAs (miRNAs) are involved in developing various diseases caused by oxidative stress and that miRNAs may be helpful to determine the inflammatory characteristics of immune responses during infection and disease. This review describes the known effects of miRNAs on reactive oxygen species to induce oxidative stress and the miRNA regulatory mechanisms involved in the uncoupling of Keap1-Nrf2 complexes. Finally, we summarized the functions of miRNAs in several antioxidant genes. Understanding the crosstalk between miRNAs and oxidative stress-inducing factors during physiological and pathological cellular events may have implications for designing more effective treatments for immune diseases.

Impact of Moriamin Forte on Testicular and Epididymal Damage in Rats with Oligoasthenospermia

To investigate the effect and mechanism of action of Moriamin Forte (MF) on oligoasthenospermia (OA) in rats exposed to multiglycosides of Tripterygium wilfordii (GTW), forty male Sprague Dawley rats were randomly divided into four groups. Rats in the control group were treated with 0.5% sodium carboxymethyl cellulose. The remaining rats were administered GTW (30 mg/kg/d) for 40 d to establish an OA model. Concurrently, the groups were treated with normal saline and low-dose (100 mg/kg/d) and high-dose (200 mg/kg/d) MF, respectively. After treatment, the number and motility of sperm cells were examined. Testicular and epididymal histomorphology changes were observed. Antioxidant indicators (SOD, CAT, MDA, TAC, and Nrf2) in testicular and epididymal tissues were detected. Apoptotic and antiapoptotic indicators (Bax and Bcl2 expression) in the testicular tissue were measured by immunohistochemistry. GTW decreased sperm count and motility, damaged testicular and epididymis tissues, impaired antioxidase activity, and increased tissue MDA levels. Meanwhile, GTW upregulated the expression of Bax and downregulated the expression of Bcl2. Western blot analysis demonstrated a decrease in the Nrf2 expression in the model group. Treatment with MF improved sperm count and motility, as well as inhibited the rate of apoptosis in the rat reproductive system. Moreover, MF improved the activity of antioxidants and increased the relative expression of the antioxidant pathway-related protein Nrf2. In conclusion, MF may reverse the GTW-induced OA by modulating the expression of apoptotic and antioxidant pathway-related proteins. This study may provide a pharmacological foundation for the use of MF in OA treatment.

Knowledge Domain and Emerging Trends in Ferroptosis Research: A Bibliometric and Knowledge-Map Analysis

Objectives

To identify the cooperation and impact of authors, countries, institutions, and journals, evaluate the knowledge base, find the hotspot trends, and detect the emerging topics regarding ferroptosis research.

Methods

The articles and reviews related to ferroptosis were obtained from the Web of Science Core Collection on November 1, 2020. Two scientometric software (CiteSpace 5.7 and VOSviewer 1.6.15) were used to perform bibliometric and knowledge-map analysis.

Results

A total of 1,267 papers were included, in 466 academic journals by 6,867 authors in 438 institutions from 61 countries/regions. The ferroptosis-related publications were increasing rapidly. Cell Death & Disease published the most papers on ferroptosis, while Cell was the top co-cited journal, publication journals and co-cited journals were major in the molecular and biology fields. The United States and China were the most productive countries; meanwhile, the University of Pittsburgh, Columbia University and Guangzhou Medical University were the most active institutions. Brent R Stockwell published the most papers, while Scott J Dixon had the most co-citations; simultaneously, active cooperation existed in ferroptosis researchers. Ten references on reviews, mechanisms, and diseases were regarded as the knowledge base. Five main aspects of ferroptosis research included regulation mechanisms, nervous system injury, cancer, relationships with other types of cell death, and lipid peroxidation. The latest hotspots were nanoparticle, cancer therapy, iron metabolism, and in-depth mechanism. Notably Nrf2 might have turning significance. The emerging topics on ferroptosis research were the further molecular mechanism of ferroptosis and the wider application of ferroptosis-related disease with advanced technology.

Conclusion

This study performed a full overview of the ferroptosis research using bibliometric and visual methods. The information would provide helpful references for scholars focusing on ferroptosis.

Analogs of imine resveratrol alleviate oxidative stress-induced neurotoxicity in PC12 cells via activation of Nrf2

Oxidative stress is closely associated with neurodegenerative, cardiovascular and metabolic diseases. Resveratrol and related compounds have shown great potential as antioxidants via either direct scavenging of abundant reactive oxygen species (ROS) or activation of the Kelch-like ECH-associated protein 1-nuclear factor (erythroid-derived 2)-like 2-antioxidant response elements pathway. In the present study, we evaluated imine resveratrol analogs (IRAs) for their neuroprotective effects against ROS in PC12 cells, which are a commonly employed model system for studies of neuronal development and function. We identified that IRA-3 (4-[[(4-hydroxyphenyl)methylene]amino]-phenol) was more potent than resveratrol at rescuing PC12 cells from H₂ O₂ -induced oxidative damage, exhibiting a recovery percentage of 60.4% at 50 μm. Our findings suggest that the neuroprotective effect of IRA-3 was achieved via multiple routes, including direct scavenging of ROS, rescue of endogenous antioxidants and activation of the Kelch-like ECH-associated protein 1-nuclear factor (erythroid-derived 2)-like 2-antioxidant response elements pathway. Our results suggest that IRA-3 may have potential for development into a possible treatment for neurodegenerative diseases.

Attenuation of Oxidative Stress and Inflammatory Response by Chronic Cannabidiol Administration Is Associated with Improved n-6/n-3 PUFA Ratio in the White and Red Skeletal Muscle in a Rat Model of High-Fat Diet-Induced Obesity

The consumption of fatty acids has increased drastically, exceeding the nutritional requirements of an individual and leading to numerous metabolic disorders. Recent data indicate a growing interest in using cannabidiol (CBD) as an agent with beneficial effects in the treatment of obesity. Therefore, our aim was to investigate the influence of chronic CBD administration on the n-6/n-3 polyunsaturated fatty acids (PUFAs) ratio in different lipid fractions, inflammatory pathway and oxidative stress parameters in the white and red gastrocnemius muscle. All the designed experiments were performed on Wistar rats fed a high-fat diet (HFD) or a standard rodent diet for seven weeks and subsequently injected with CBD (10 mg/kg once daily for two weeks) or its vehicle. Lipid content and oxidative stress parameters were assessed using gas-liquid chromatography (GLC), colorimetric and/or immunoenzymatic methods, respectively. The total expression of proteins of an inflammatory pathway was measured by Western blotting. Our results revealed that fatty acids (FAs) oversupply is associated with an increasing oxidative stress and inflammatory response, which results in an excessive accumulation of FAs, especially of n-6 PUFAs, in skeletal muscles. We showed that CBD significantly improved the n-6/n-3 PUFA ratio and shifted the equilibrium towards anti-inflammatory n-3 PUFAs, particularly in the red gastrocnemius muscle. Additionally, CBD prevented generation of lipid peroxidation products and attenuated inflammatory response in both types of skeletal muscle. In summary, the results mentioned above indicate that CBD presents potential therapeutic properties with respect to the treatment of obesity and related disturbances.

OsKEAP1 Interacts with OsABI5 and Its Downregulation Increases the Transcription of OsABI5 and the ABA Response Genes in Germinating Rice Seeds

Kelch-like ECH-associated protein 1 (KEAP1)-nuclear factor E2-related factor 2 (NRF2) is the key antioxidant system in animals. In a previous study, we identified a probable KEAP1 ortholog in rice, OsKEAP1, and demonstrated that the downregulation of OsKEAP1 could alter the redox system and impair plant growth, as well as increase the susceptibility to abscisic acid (ABA) in seed germination. However, no NRF2 orthologs have been identified in plants and the mechanism underlying the phenotype changes of downregulated oskeap1 mutants is yet unknown. An in silico search showed that OsABI5 is the gene that encodes a protein with the highest amino acid identity score (38.78%) to NRF2 in rice. In this study, we demonstrated that, via yeast two-hybrids analysis and bimolecular fluorescence complementation assays, OsKEAP1 interacted with OsABI5 via its Kelch repeat domain in the nucleus. In germinating seeds, the expression of OsKEAP1 was significantly downregulated in oskeap1-1 (39.5% that of the wild-type (WT)) and oskeap1-2 (64.5% that of WT), while the expression of OsABI5 was significantly increased only in oskeap1-1 (247.4% that of WT) but not in oskeap1-2 (104.8% that of WT). ABA (0.5 μM) treatment significantly increased the expression of OsKEAP1 and OsABI5 in both the oskeap1 mutants and WT, and 4 days post treatment, the transcription level of OsABI5 became significantly greater in oskeap1-1 (+87.2%) and oskeap1-2 (+55.0%) than that in the WT. The ABA-responsive genes (OsRab16A and three late embryogenesis abundant genes), which are known to be activated by OsABI5, became more responsive to ABA in both oskeap1 mutants than in the WT. The transcript abundances of genes that regulate OsABI5, e.g., OsSnRK2 (encodes a kinase that activates OsABI5), OsABI1, and OsABI2 (both encode proteins binding to OsSnRK2 and are involved in ABA signaling) were not significantly different between the two oskeap1 mutants and the WT. These results demonstrated that OsKEAP1 played a role in the ABA response in rice seed germination via regulating OsABI5, which is the key player in the ABA response. In-depth analyses of the components and their action mode of the KEAP1-NRF2 and ABA signaling pathways suggested that OsKEAP1 likely formed a complex with OsABI5 and OsKEG, and OsABI5 was ubiquitinated by OsKEG and subsequently degraded under physiological conditions; meanwhile, under oxidative stress or with increased an ABA level, OsABI5 was released from the complex, phosphorylated, and transactivated the ABA response genes. Therefore, OsKEAP1-OsABI5 bore some resemblance to KEAP1-NRF2 in terms of its function and working mechanism.

Anticancer Therapy with HDAC Inhibitors: Mechanism-Based Combination Strategies and Future Perspectives

The increasing knowledge of molecular drivers of tumorigenesis has fueled targeted cancer therapies based on specific inhibitors. Beyond "classic" oncogene inhibitors, epigenetic therapy is an emerging field. Epigenetic alterations can occur at any time during cancer progression, altering the structure of the chromatin, the accessibility for transcription factors and thus the transcription of genes. They rely on post-translational histone modifications, particularly the acetylation of histone lysine residues, and are determined by the inverse action of histone acetyltransferases (HATs) and histone deacetylases (HDACs). Importantly, HDACs are often aberrantly overexpressed, predominantly leading to the transcriptional repression of tumor suppressor genes. Thus, histone deacetylase inhibitors (HDACis) are powerful drugs, with some already approved for certain hematological cancers. Albeit HDACis show activity in solid tumors as well, further refinement and the development of novel drugs are needed. This review describes the capability of HDACis to influence various pathways and, based on this knowledge, gives a comprehensive overview of various preclinical and clinical studies on solid tumors. A particular focus is placed on strategies for achieving higher efficacy by combination therapies, including phosphoinositide 3-kinase (PI3K)-EGFR inhibitors and hormone- or immunotherapy. This also includes new bifunctional inhibitors as well as novel approaches for HDAC degradation via PROteolysis-TArgeting Chimeras (PROTACs).

Molecular Iodine Has Extrathyroidal Effects as an Antioxidant, Differentiator, and Immunomodulator

Most investigations of iodine metabolism in humans and animals have focused on its role in thyroid function. However, considerable evidence indicates that iodine could also be implicated in the physiopathology of other organs. We review the literature that shows that molecular iodine (I₂) exerts multiple and complex actions on the organs that capture it, not including its effects as part of thyroid hormones. This chemical form of iodine is internalized by a facilitated diffusion system that is evolutionary conserved, and its effects appear to be mediated by a variety of mechanisms and pathways. As an oxidized component, it directly neutralizes free radicals, induces the expression of type II antioxidant enzymes, or inactivates proinflammatory pathways. In neoplastic cells, I₂ generates iodolipids with nuclear actions that include the activation of apoptotic pathways and the inhibition of markers related to stem cell maintenance, chemoresistance, and survival. Recently, I2 has been postulated as an immune modulator that depending on the cellular context, can function as an inhibitor or activator of immune responses. We propose that the intake of molecular iodine is increased in adults to at least 1 mg/day in specific pathologies to obtain the potential extrathyroid benefits described in this review.

Acidic fibroblast growth factor attenuates type 2 diabetes-induced demyelination via suppressing oxidative stress damage

Prolonged type 2 diabetes mellitus (T2DM) produces a common complication, peripheral neuropathy, which is accompanied by nerve fiber disorder, axon atrophy, and demyelination. Growing evidence has characterized the beneficial effects of acidic fibroblast growth factor (aFGF) and shown that it relieves hyperglycemia, increases insulin sensitivity, and ameliorates neuropathic impairment. However, there is scarce evidence on the role of aFGF on remodeling of aberrant myelin under hyperglycemia condition. Presently, we observed that the expression of aFGF was rapidly decreased in a db/db T2DM mouse model. Administration of exogenous aFGF was sufficient to block acute demyelination and nerve fiber disorganization. Furthermore, this strong anti-demyelinating effect was most likely dominated by an aFGF-mediated increase of Schwann cell (SC) proliferation and migration as well as suppression of its apoptosis. Mechanistically, the beneficial biological effects of aFGF on SC behavior and abnormal myelin morphology were likely due to the inhibition of hyperglycemia-induced oxidative stress activation, which was most likely activated by kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid-derived-like 2 (Nrf2) signaling. Thus, this evidence indicates that aFGF is a promising protective agent for relieving myelin pathology through countering oxidative stress signaling cascades under diabetic conditions.

Bibliometric Analysis of the Inflammasome and Pyroptosis in Brain

Background: Considering the pivotal role of inflammasome/pyroptosis in biological function, we visually analyzed the research hotspots of inflammasome/pyroptosis related to the brain in this work through the method of bibliometrics from the Web of Science (WOS) Core database over the past two decades.

Methods: Documents were retrieved from WOS Core Collection on October 16, 2020. The search terms and strategies used for the WOS database are as follow: # 1, “pyroptosis”; # 2, “pyroptotic”; # 3, “inflammasome”; # 4, “pyroptosome”; # 5 “brain”; # 6, “# 1” OR “# 2” OR “# 3” OR “# 4”; # 7, “# 5” AND “# 6”. We selected articles and reviews published in English from 2000 to 2020. Visualization analysis and statistical analysis were performed by VOSviewer 1.6.15 and CiteSpace 5.7. R2.

Results: 1,222 documents were selected for analysis. In the approximately 20 years since the pyroptosis was first presented, the publications regarding the inflammasome and pyroptosis in brain were presented since 2005. The number of annual publications increased gradually over a decade, which are involved in this work, and will continue to increase in 2020. The most prolific country was China with 523 documents but the United States was with 16,328 citations. The most influential author was Juan Pablo de Rivero Vaccari with 27 documents who worked at the University of Miami. The bibliometric analysis showed that inflammasome/pyroptosis involved a variety of brain cell types (microglia, astrocyte, neuron, etc.), physiological processes, ER stress, mitochondrial function, oxidative stress, and disease (traumatic brain injuries, stroke, Alzheimer’s disease, and Parkinson’s disease).

Conclusion: The research of inflammasome/pyroptosis in brain will continue to be the hotspot. We recommend investigating the mechanism of mitochondrial molecules involved in the complex crosstalk of pyroptosis and regulated cell deaths (RCDs) in brain glial cells, which will facilitate the development of effective therapeutic strategies targeting inflammasome/pyroptosis and large-scale clinical trials. Thus, this study presents the trend and characteristic of inflammasome/pyroptosis in brain, which provided a helpful bibliometric analysis for researchers to further studies.

Melittin Ameliorates Endotoxin-Induced Acute Kidney Injury by Inhibiting Inflammation, Oxidative Stress, and Cell Death in Mice

Sepsis-related acute kidney injury (AKI) is a worldwide health problem, and its pathogenesis involves multiple pathways. Lipopolysaccharide (LPS) is an endotoxin that induces systemic inflammatory responses. Melittin, a main constituent of bee venom, exerts several biological activities such as antioxidant, anti-inflammatory, and antiapoptotic actions. However, whether melittin protects against endotoxin-induced AKI remains undetermined. Here, we aimed to examine the potential action of melittin on LPS-induced renal injury and explore the mechanisms. We showed that acute renal failure and structural damage after injection of LPS were markedly attenuated by administration of melittin. The peptide also suppressed expression of markers of direct tubular damage in kidneys of the LPS-treated mice. Mechanistically, melittin reduced systemic and renal levels of cytokines and inhibited renal accumulation of immune cells with concomitant suppression of nuclear factor kappa-B pathway. Increased amounts of lipid peroxidation products after LPS treatment were largely decreased by melittin. Additionally, the peptide decreased expression of nicotinamide adenine dinucleotide phosphate oxidase 4 and enhanced nuclear factor erythroid-2-related factor 2-mediated antioxidant defenses. Moreover, melittin inhibited apoptotic and necroptotic cell death after LPS treatment. Lastly, we showed that melittin improved the survival rate of LPS-injected mice. These results suggest that melittin ameliorates endotoxin-induced AKI and mortality through inhibiting inflammation, oxidative injury, and apoptotic and necroptotic death of tubular epithelial cells.

Research trends, hot spots and prospects for necroptosis in the field of neuroscience

There are two types of cell death-apoptosis and necrosis. Apoptosis is cell death regulated by cell signaling pathways, while necrosis has until recently been considered a passive mechanism of cell death caused by environmental pressures. However, recent studies show that necrosis can also be regulated by specific cell signaling pathways. This mode of death, termed necroptosis, has been found to be related to the occurrence and development of many diseases. We used bibliometrics to analyze the global output of literature on necroptosis in the field of neuroscience published in the period 2007–2019 to identify research hotspots and prospects. We included 145 necroptosis-related publications and 2239 references published in the Web of Science during 2007–2019. Visualization analysis revealed that the number of publications related to necroptosis has increased year by year, reaching a peak in 2019. China is the country with the largest number of publications. Key word and literature analyses demonstrated that mitochondrial function change, stroke, ischemia/reperfusion and neuroinflammation are likely the research hotspots and future directions of necroptosis research in the nervous system. The relationship between immune response-related factors, damage-associated molecular patterns, pathogen-associated molecular patterns and necroptosis may become a potential research hotspot in the future. Taken together, our findings suggest that although the inherent limitations of bibliometrics may affect the accuracy of the literature-based prediction of research hotspots, the results obtained from the included publications can provide a reference for the study of necroptosis in the field of neuroscience.

Cruciferous vegetables: rationale for exploring potential salutary effects of sulforaphane-rich foods in patients with chronic kidney disease

Sulforaphane (SFN) is a sulfur-containing isothiocyanate found in cruciferous vegetables (Brassicaceae) and a well-known activator of nuclear factor-erythroid 2-related factor 2 (Nrf2), considered a master regulator of cellular antioxidant responses. Patients with chronic diseases, such as diabetes, cardiovascular disease, cancer, and chronic kidney disease (CKD) present with high levels of oxidative stress and a massive inflammatory burden associated with diminished Nrf2 and elevated nuclear transcription factor-κB-κB expression. Because it is a common constituent of dietary vegetables, the salutogenic properties of sulforaphane, especially it’s antioxidative and anti-inflammatory properties, have been explored as a nutritional intervention in a range of diseases of ageing, though data on CKD remain scarce. In this brief review, the effects of SFN as a senotherapeutic agent are described and a rationale is provided for studies that aim to explore the potential benefits of SFN-rich foods in patients with CKD.

Dual and Opposite Roles of Reactive Oxygen Species (ROS) in Chagas Disease: Beneficial on the Pathogen and Harmful on the Host

Chagas disease is a neglected tropical disease, which affects an estimate of 6-7 million people worldwide. Chagas disease is caused by Trypanosoma cruzi, which is a eukaryotic flagellate unicellular organism. At the primary infection sites, these parasites are phagocytized by macrophages, which produce reactive oxygen species (ROS) in response to the infection with T. cruzi. The ROS produce damage to the host tissues; however, macrophage-produced ROS is also used as a signal for T. cruzi proliferation. At the later stages of infection, mitochondrial ROS is produced by the infected cardiomyocytes that contribute to the oxidative damage, which persists at the chronic stage of the disease. The oxidative damage leads to a functional impairment of the heart. In this review article, we will discuss the mechanisms by which T. cruzi is able to deal with the oxidative stress and how this helps the parasite growth at the acute phase of infection and how the oxidative stress affects the cardiomyopathy at the chronic stage of the Chagas disease. We will describe the mechanisms used by the parasite to deal with ROS and reactive nitrogen species (RNS) through the trypanothione and the mechanisms used to repair the damaged DNA. Also, a description of the events produced by ROS at the acute and chronic stages of the disease is presented. Lastly, we discuss the benefits of ROS for T. cruzi growth and proliferation and the possible mechanisms involved in this phenomenon. Hypothesis is put forward to explain the molecular mechanisms by which ROS triggers parasite growth and proliferation and how ROS is able to produce a long persisting damage on cardiomyocytes even in the absence of the parasite.

Anti-Viral Potential and Modulation of Nrf2 by Curcumin: Pharmacological Implications

Nuclear factor erythroid 2-related factor 2 (Nrf2) is an essential transcription factor that maintains the cell's redox balance state and reduces inflammation in different adverse stresses. Under the oxidative stress, Nrf2 is separated from Kelch-like ECH-associated protein 1 (Keap1), which is a key sensor of oxidative stress, translocated to the nucleus, interacts with the antioxidant response element (ARE) in the target gene, and then activates the transcriptional pathway to ameliorate the cellular redox condition. Curcumin is a yellow polyphenolic curcuminoid from Curcuma longa (turmeric) that has revealed a broad spectrum of bioactivities, including antioxidant, anti-inflammatory, anti-tumor, and anti-viral activities. Curcumin significantly increases the nuclear expression levels and promotes the biological effects of Nrf2 via the interaction with Cys151 in Keap1, which makes it a marvelous therapeutic candidate against a broad range of oxidative stress-related diseases, including type 2 diabetes (T2D), neurodegenerative diseases (NDs), cardiovascular diseases (CVDs), cancers, viral infections, and more recently SARS-CoV-2. Currently, the multifactorial property of the diseases and lack of adequate medical treatment, especially in viral diseases, result in developing new strategies to finding potential drugs. Curcumin potentially opens up new views as possible Nrf2 activator. However, its low bioavailability that is due to low solubility and low stability in the physiological conditions is a significant challenge in the field of its efficient and effective utilization in medicinal purposes. In this review, we summarized recent studies on the potential effect of curcumin to activate Nrf2 as the design of potential drugs for a viral infection like SARS-Cov2 and acute and chronic inflammation diseases in order to improve the cells' protection.

Patent Review (2017-2020) of the Keap1/Nrf2 Pathway Using PatSeer Pro: Focus on Autoimmune Diseases

Research on the antioxidant pathway comprising the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) and its cytoplasmic inhibitor Kelch-like ECH-associated protein 1 (Keap1) is ever increasing. As modulators of this pathway have started to be used in clinical trials and clinical practice, Nrf2 has become the subject of several patents. To assess the patent landscape of the last three years on Nrf2 and evaluate the main fields they refer to, we used the web-based tool PatSeer Pro to identify patents mentioning the Nrf2 pathway between January 2017 and May 2020. This search resulted in 509 unique patents that focus on topics such as autoimmune, neurodegenerative, liver, kidney, and lung diseases and refer to modulators (mainly activators) of the Nrf2 pathway as potential treatments. Autoimmunity emerged as the main theme among the topics of Nrf2 patents, including a broad range of diseases, such as systemic sclerosis, systemic lupus erythematosus, multiple sclerosis, inflammatory bowel diseases, Hashimoto's thyroiditis, etc.; however, there was a dearth of experimental support for the respective patents' claims. Given that chronic inflammation is the main element of the pathophysiology of most autoimmune diseases, the majority of patents referring to activation of Nrf2 as a method to treat autoimmune diseases base their claims on the well-established anti-inflammatory role of Nrf2. In conclusion, there is strong interest in securing intellectual property rights relating to the potential use of Nrf2 pathway activators in a variety of diseases, and this trend parallels the rise in related research publications. However, in the case of autoimmunity, more research is warranted to support the potential beneficial effects of Nrf2 modulation in each disease.

Antarctic Krill Oil Attenuates Oxidative Stress via the KEAP1-NRF2 Signaling in Patients with Coronary Heart Disease

Background

Antarctic krill oil (AKO) has strong antioxidant activities and is effective for alleviating coronary heart disease (CHD). Kelch-like ECH-associated protein 1-NF-E2-related factor 2 (KEAP1-NRF2) axis is a crucial antioxidant signaling pathway. Thus, AKO may exert its antioxidant effects on CHD patients via KEAP1-NRF2 signaling.

Methods

AKO fatty acid (FA) profiles were analyzed by using gas chromatography (GC). One hundred CHD patients were divided into the intervention (IG, AKO) and control (CG, placebo) groups. Before and after 1, 2, and 3 months of intervention, we measured serum levels of reactive oxygen species (ROS), 8-hydroxy-2-deoxyguanosine (8-OHdG), nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD), reduced glutathione (GSH), and glutathione peroxidase (GPx), and KEAP1 and NRF2 levels in peripheral blood leukocytes (PBLs). Serum FAs were measured by GC at baseline and after 3-month intervention.

Results

AKO contains rich eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which is more than 27% of total FA. The levels of EPA and DHA, KEAP1, and NRF2 in the IG group were higher than those in the CG group (p < 0.05). Serum levels of ROS, 8-OHdG, NO, and MDA in the IG group were lower than those in the CG group, whereas the levels of SOD, GSH, and GPx in the IG group were higher than those in the CG group (p < 0.05). Serum levels of saturated fatty acids (UFA) in the IG group were higher than those in the CG group, whereas reverse results were obtained for the levels of saturated fatty acids (SFA). Serum levels of EPA and DHA had a strong negative relationship with the level of ROS, whereas the ROS level had a strong negative relationship with the levels of KEAP1-NRF2.

Conclusion

AKO increases antioxidant capacities of CHD patients via the KEAP1-NRF2 signaling in the PBL.

Qualitative and Quantitative Analysis of Ukrainian Iris Species: A Fresh Look on Their Antioxidant Content and Biological Activities

The major groups of antioxidant compounds (isoflavonoids, xanthones, hydroxycinnamic acids) in the rhizome methanol extracts of four Ukrainian Iris sp. (Iris pallida, Iris hungarica, Iris sibirica, and Iris variegata) were qualitatively and quantitatively analyzed using HPLC-DAD and UPLC-MS/MS. Gallic acid, caffeic acid, mangiferin, tectoridin, irigenin, iristectorigenin B, irisolidone, 5,6-dihydroxy-7,8,3',5'-tetramethoxyisoflavone, irisolidone-7-O-β-d-glucopyranoside, germanaism B, and nigricin were recognized by comparing their UV/MS spectra, chromatographic retention time (tR) with those of standard reference compounds. I. hungarica and I. variegata showed the highest total amount of phenolic compounds. Germanaism B was the most abundant component in the rhizomes of I. variegata (7.089 ± 0.032 mg/g) and I. hungarica (6.285 ± 0.030 mg/g). The compound analyses showed good calibration curve linearity (r² > 0.999) and low detection and quantifications limit. These results validated the method for its use in the simultaneous quantitative evaluation of phenolic compounds in the studied Iris sp. I. hungarica and I. variegata rhizomes exhibited antioxidant activity, as demonstrated by the HPLC-ABTS system and NRF2 expression assay and anti-inflammatory activity on respiratory burst in human neutrophils. Moreover, the extracts showed anti-allergic and cytotoxic effects against cancer cells. Anti-coronavirus 229E and lipid formation activities were also evaluated. In summary, potent antioxidant marker compounds were identified in the examined Iris sp.

Glutamate-Cysteine Ligase Catalytic Subunit Attenuated Hepatitis C Virus-Related Liver Fibrosis and Suppressed Endoplasmic Reticulum Stress

The study aimed to clarify the role and molecular mechanism of glutamate-cysteine ligase catalytic subunit (GCLC) in modulating Hepatitis C virus (HCV)-related liver fibrosis. Twenty patients with HCV-related liver fibrosis and 15 healthy controls were enrolled. Differentially expressed plasma mRNAs were detected by digital gene expression profile analysis and validated by qRT-PCR. Hepatic histopathology was observed by H&E and Masson stained liver sections. The mRNA and protein expression of GCLC, endoplasmic reticulum (ER) stress markers, and inflammatory and fibrogenic factors were detected in liver tissues from patients with HCV-related hepatic fibrosis and HCV core protein-expressing LX-2. The GCLC-overexpressing LX-2 were established by transfecting puc19-GCLC plasmid. Then, glutathione and reactive oxygen species (ROS) levels were measured respectively by spectrophotometric diagnostic kit and dihydrodichlorofluorescein diacetate kit. GCLC were dramatically down-regulated in HCV-related fibrotic livers and activated HSCs, which companied with up-regulation of ER stress-related genes, including inositol-requiring 1 (IRE1) and glucose-regulated protein 78 (GRP78). Also, the proinflammatory and profibrogenic gene, including nuclear factor kappa B (NF-κB), tumor necrosis factor α (TNFα), and transforming growth factor 1(TGFβ1), was highly upregulated. Overexpression of GCLC in hepatic stellate cells could suppress α-SMA and collagen I expression, produce hepatic GSH and reduce ROS, and down-regulate IRE1, GRP78, NF-κB, TNF-α, and TGFβ1 expression. GCLC was a negative regulatory factor in the development of HCV-related liver fibrosis and might be a potential therapeutic target for liver fibrosis.

An Update on the Role of Dietary Phytochemicals in Human Skin Cancer: New Insights into Molecular Mechanisms

Human skin is continuously subjected to environmental stresses, as well as extrinsic and intrinsic noxious agents. Although skin adopts various molecular mechanisms to maintain homeostasis, excessive and repeated stresses can overwhelm these systems, leading to serious cutaneous damage, including both melanoma and non-melanoma skin cancers. Phytochemicals present in the diet possess the desirable effects of protecting the skin from damaging free radicals as well as other benefits. Dietary phytochemicals appear to be effective in preventing skin cancer and are inexpensive, widely available, and well tolerated. Multiple in vitro and in vivo studies have demonstrated the significant anti-inflammatory, antioxidant, and anti-angiogenic characteristics of dietary phytochemicals against skin malignancy. Moreover, dietary phytochemicals affect multiple important cellular processes including cell cycle, angiogenesis, and metastasis to control skin cancer progression. Herein, we discuss the advantages of key dietary phytochemicals in whole fruits and vegetables, their bioavailability, and underlying molecular mechanisms for preventing skin cancer. Current challenges and future prospects for research are also reviewed. To date, most of the chemoprevention investigations have been conducted preclinically, and additional clinical trials are required to conform and validate the preclinical results in humans.