Sulforaphane prevents angiotensin II-induced cardiomyopathy by activation of Nrf2 via stimulating the Akt/GSK-3ß/Fyn pathway

Resveratrol Attenuates High Glucose-Induced Osteoblast Dysfunction via AKT/GSK3β/FYN-Mediated NRF2 Activation

Osteoblast dysfunction, induced by high glucose (HG), negatively impacts bone homeostasis and contributes to the pathology of diabetic osteoporosis (DOP). One of the most widely recognized mechanisms for osteoblast dysfunction is oxidative stress. Resveratrol (RES) is a bioactive antioxidant compound to combat oxidative damage. However, its role in the protection of HG-induced osteoblast dysfunction has not been clarified. Therefore, our study aimed to explore potential regulatory mechanisms of RES for attenuating HG-induced osteoblast dysfunction. Our results showed that osteoblast dysfunction under HG condition was significantly ameliorated by RES via the activation of nuclear factor erythroid 2-related factor (NRF2) to suppress oxidative stress. Furthermore, using Nrf2-shRNA and wortmannin, we identified that activation of NRF2 via RES was regulated by the AKT/glycogen synthase kinase 3β (GSK3β)/FYN axis.

Sulforaphane Ameliorates the Intestinal Injury in Necrotizing Enterocolitis by Regulating the PI3K/Akt/GSK-3β Signaling Pathway

Objective

Necrotizing enterocolitis (NEC) is a serious neonatal disease; this study aims to investigate the role of sulforaphane (SFN) in NEC-induced intestinal injury.

Methods

An animal model of NEC was established in newborn mice and intragastrically administrated with SFN; then, the general status and survival of the mice were observed. H&E staining was used to observe the pathological changes of intestinal tissues. ELISA, immunohistochemical staining, and flow cytometry assays were used to detect the levels of inflammatory factors, including TNF-α, IL-6, and IL-17, the expression of Bax, Bcl-2, TLR4, and NF-κB, and the percentages of the Th17 and Treg cells, respectively. GSK-3β expression levels were measured by immunofluorescence. IEC-6 and FHC cells were induced with LPS to mimic NEC in vitro and coincubated with SFN; then, the inflammatory factor levels and cell apoptosis rate were detected. Finally, Western blot was used to assess the expression of PI3K/Akt/GSK-3β pathway-related proteins in vitro and in vivo.

Results

SFN improved the survival rate of NEC mice during modeling, alleviated the severity of the intestinal injury, and reduced the proportion of Th17/Treg cells. SFN could inhibit TLR4 and NF-κB levels, decrease the release of inflammatory factors TNF-α and IL-6, suppress Bax expression, increase Bcl-2 expression, and inhibit apoptosis both in in vitro and in vivo models of NEC. Meanwhile, SFN regulated the expression of PI3K/Akt/GSK-3β pathway-related proteins in vitro and in vivo.

Conclusion

SFN relieved the inflammatory response and apoptosis by regulating the PI3K/Akt/GSK-3β signaling pathway, thereby alleviating NEC in model mice and cells.

Sulforaphane alleviates hypoxic vestibular vertigo (HVV) by increasing NO production via upregulating the expression of NRF2

Sulforaphane (SFP) treatment represses oxidative stress by activating NRF2. Meanwhile, SFP may also increase the production of nitric oxide (NO) and activate the signaling pathway of cyclic guanosine monophosphate (cGMP), which is involved in the pathogenesis of hypoxic vestibular vertigo (HVV). However, it remains unknown as whether SFP plays a therapeutic role in the treatment of HVV. A rat model of HVV was established to measure the levels of escape latency, malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD) in the aorta tissues. Quantitative real-time PCR was performed to evaluate the expression of NRF2 mRNA, and Western blot and immunohistochemistry were carried out to analyze the expression of NRF2 protein. ELISA was used to examine the production of NO and cGMP. SFP treatment helped to maintain the escape latency and MDA, GSH, SOD concentrations in the brain of HVV rats, and recovered the expression of NRF2 inhibited in the brain of HVV rats. SFP treatment also elevated NO and cGMP production that was down-regulated in the brain of HVV rats. On the cellular level, SFP enhanced the expression of NRF2, reduced the concentrations of MDA, GSH and SOD, and promoted the production of NO and cGMP in a dose-dependent manner. In this study, we treated an animal model of HVV with SFP to investigate its effect on NO production and oxidative stress. Our work provided a mechanistic insight into the therapeutic effect of SFP on the treatment of HVV.

The Interplay between Autophagy and Redox Signaling in Cardiovascular Diseases

Reactive oxygen and nitrogen species produced at low levels under normal cellular metabolism act as important signal molecules. However, at increased production, they cause damage associated with oxidative stress, which can lead to the development of many diseases, such as cardiovascular, metabolic, neurodegenerative, diabetes, and cancer. The defense systems used to maintain normal redox homeostasis plays an important role in cellular responses to oxidative stress. The key players here are Nrf2-regulated redox signaling and autophagy. A tight interface has been described between these two processes under stress conditions and their role in oxidative stress-induced diseases progression. In this review, we focus on the role of Nrf2 as a key player in redox regulation in cell response to oxidative stress. We also summarize the current knowledge about the autophagy regulation and the role of redox signaling in this process. In line with the focus of our review, we describe in more detail information about the interplay between Nrf2 and autophagy pathways in myocardium and the role of these processes in cardiovascular disease development.

Fibroblast growth factor 20 attenuates pathological cardiac hypertrophy by activating the SIRT1 signaling pathway

Cardiac hypertrophy occurs initially in response to an increased cardiac load as a compensatory mechanism to maintain cardiac output. However, sustained pathological hypertrophy can develop into heart failure and cause sudden death. Fibroblast growth factor 20 (FGF20) is a member of the fibroblast growth factor family, which involved in apoptosis, aging, inflammation, and autophagy. The precise function of FGF20 in pathological cardiac hypertrophy is unclear. In this study, we demonstrated that FGF20 was significantly decreased in response to hypertrophic stimulation. In contrast, overexpression of FGF20 protected against pressure overload-induced cardiac hypertrophy. Mechanistically, we found that FGF20 upregulates SIRT1 expression, causing deacetylation of FOXO1; this effect promotes the transcription of downstream antioxidant genes, thus inhibits oxidative stress. In content, the anti-hypertrophic effect of FGF20 was largely counteracted in SIRT1-knockout mice, accompanied by an increase in oxidative stress. In summary, our findings reveal a previously unknown protective effect of FGF20 on pathological cardiac hypertrophy by reducing oxidative stress through activation of the SIRT1 signaling pathway. FGF20 is a potential novel molecular target for preventing and treating pressure overload-induced myocardial injury.

Novel oral edaravone attenuates diastolic dysfunction of diabetic cardiomyopathy by activating the Nrf2 signaling pathway

Oxidative stress plays a crucial role in the pathophysiology of diastolic dysfunction associated with diabetic cardiomyopathy. Novel oral edaravone (OED) alleviates oxidative stress by scavenging free radicals and may be suitable for the treatment of chronic diseases such as diabetic cardiomyopathy. Oral administration of OED to type 2 diabetic rats (induced by high-sugar/high-fat diet and intraperitoneal injection of streptozotocin) for 4 w decreased malondialdehyde and increased superoxide dismutase. Moreover, it significantly improved ratios of early to late diastolic peak velocity, myocardium hypertrophy accompanied by decreased cross-sectional areas of cardiomyocytes, the proportion of apoptotic cells, collagen volume fractions, and deposition of collagen I/III. In H9c2 cells, OED reduced reactive oxygen species, cell surface area, and numbers of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling-positive cells induced by glucolipotoxicity. OED remarkably upregulated expression of the nuclear factor E2-related factor (Nrf2) signaling pathway both in vivo and in vitro. In addition, OED promoted Nrf2 nuclear translocation and upregulated nicotinamide adenine dinucleotide phosphate quinone oxidoreductase and heme oxygenase. Silencing of Nrf2 abolished the protective effect of OED in H9c2 cells. Our findings demonstrate that OED has the therapeutic potential to ameliorate diastolic dysfunction associated with diabetic cardiomyopathy. Its effect was mainly achieved by attenuating hyperglycemia and hyperlipidemia-induced cardiomyocyte hypertrophy, apoptosis, and fibrosis by activating the Nrf2 signaling pathway.

Sulforaphane Does Not Protect Right Ventricular Systolic and Diastolic Functions in Nrf2 Knockout Pulmonary Artery Hypertension Mice

PURPOSE

Nrf2 is a nuclear transcription factor and plays an important role in the regulation of oxidative stress and inflammation. We recently demonstrated that sulforaphane (SFN) protected mice from developing pulmonary arterial hypertension (PAH) and right ventricular (RV) dysfunction by elevating cardiac Nrf2 expression and function. Here we further investigate Nrf2 dependence for SFN-mediated prevention of PAH and RV dysfunction in an Nrf2 knockout mouse model.

METHODS

We used male global Nrf2-knockout mice and male C57/6 J wild type mice in the following groups: Control group received room air and vehicle control; SuHx group received SU5416 and 10% hypoxia for 4 weeks to induce PAH; SuHx+SFN group received both SuHx and sulforaphane, a Nrf2 activator, for 4 weeks. Transthoracic echocardiography was performed to quantify RV function and estimate pulmonary vascular resistance over 4 weeks. PAH was confirmed using invasive RV systolic pressure measurement at 4 weeks.

RESULTS

All Nrf2 knockout mice survived the 4-week SuHx induction of PAH. SuHx caused progressive RV diastolic/systolic dysfunction and increased RV systolic pressure. The development of RV diastolic dysfunction occurred earlier in the Nrf2 knockout PAH mice when compared with the wide type PAH mice. SFN partially or completely reversed SuHx-induced RV diastolic/systolic dysfunction and increased RV systolic pressure in wild-type mice, but not in Nrf2 knockout mice.

CONCLUSION

Our findings demonstrated the essential role of Nrf2 in SFN-mediated prevention of RV dysfunction and PAH, and increasing Nrf2 activity in patients with PAH may have therapeutic potential.

Ferroptosis is essential for diabetic cardiomyopathy and is prevented by sulforaphane via AMPK/NRF2 pathways

Herein, we define the role of ferroptosis in the pathogenesis of diabetic cardiomyopathy (DCM) by examining the expression of key regulators of ferroptosis in mice with DCM and a new ex vivo DCM model. Advanced glycation end-products (AGEs), an important pathogenic factor of DCM, were found to induce ferroptosis in engineered cardiac tissues (ECTs), as reflected through increased levels of Ptgs2 and lipid peroxides and decreased ferritin and SLC7A11 levels. Typical morphological changes of ferroptosis in cardiomyocytes were observed using transmission electron microscopy. Inhibition of ferroptosis with ferrostatin-1 and deferoxamine prevented AGE-induced ECT remodeling and dysfunction. Ferroptosis was also evidenced in the heart of type 2 diabetic mice with DCM. Inhibition of ferroptosis by liproxstatin-1 prevented the development of diastolic dysfunction at 3 months after the onset of diabetes. Nuclear factor erythroid 2-related factor 2 (NRF2) activated by sulforaphane inhibited cardiac cell ferroptosis in both AGE-treated ECTs and hearts of DCM mice by upregulating ferritin and SLC7A11 levels. The protective effect of sulforaphane on ferroptosis was AMP-activated protein kinase (AMPK)-dependent. These findings suggest that ferroptosis plays an essential role in the pathogenesis of DCM; sulforaphane prevents ferroptosis and associated pathogenesis via AMPK-mediated NRF2 activation. This suggests a feasible therapeutic approach with sulforaphane to clinically prevent ferroptosis and DCM.

Signaling Pathways Related to Oxidative Stress in Diabetic Cardiomyopathy

Diabetes is a chronic metabolic disease that is increasing in prevalence and causes many complications. Diabetic cardiomyopathy (DCM) is a complication of diabetes that is associated with high mortality, but it is not well defined. Nevertheless, it is generally accepted that DCM refers to a clinical disease that occurs in patients with diabetes and involves ventricular dysfunction, in the absence of other cardiovascular diseases, such as coronary atherosclerotic heart disease, hypertension, or valvular heart disease. However, it is currently uncertain whether the pathogenesis of DCM is directly attributable to metabolic dysfunction or secondary to diabetic microangiopathy. Oxidative stress (OS) is considered to be a key component of its pathogenesis. The production of reactive oxygen species (ROS) in cardiomyocytes is a vicious circle, resulting in further production of ROS, mitochondrial DNA damage, lipid peroxidation, and the post-translational modification of proteins, as well as inflammation, cardiac hypertrophy and fibrosis, ultimately leading to cell death and cardiac dysfunction. ROS have been shown to affect various signaling pathways involved in the development of DCM. For instance, OS causes metabolic disorders by affecting the regulation of PPARα, AMPK/mTOR, and SIRT3/FOXO3a. Furthermore, OS participates in inflammation mediated by the NF-κB pathway, NLRP3 inflammasome, and the TLR4 pathway. OS also promotes TGF-β-, Rho-ROCK-, and Notch-mediated cardiac remodeling, and is involved in the regulation of calcium homeostasis, which impairs ATP production and causes ROS overproduction. In this review, we summarize the signaling pathways that link OS to DCM, with the intention of identifying appropriate targets and new antioxidant therapies for DCM.

A characterized saponin extract of Panax japonicus suppresses hepatocyte EMT and HSC activation in vitro and CCl4-provoked liver fibrosis in mice: Roles of its modulatory effects on the Akt/GSK3β/Nrf2 cascade

BACKGROUND AND PURPOSE

Liver fibrosis constitutes a pathologic condition resulting in a series of advanced liver diseases. Oleanane-type saponins are distinctive active constituents in the medicinal plant Panax japonicus C. A. Mey (P. japonicus). Herein, we assessed protective effects of a characterized saponin extract of rhizomes of P. japonicus (SEPJ) on hepatocyte EMT and HSC activation in vitro and liver fibrosis in mice. We also investigated molecular mechanisms underlying the hepatoprotective activity of SEPJ.

METHODS

EMT of AML-12 hepatocytes was evaluated by observing morphology of cells and quantifying EMT marker proteins. Activation of LX-2 HSCs was assessed via scratch assay, transwell assay, and EdU-incorporation assay, and by quantifying activation marker proteins. Liver fibrosis in mice was evaluated by HE, SR, and Masson staining, and by measuring related serum indicators. Immunoblotting and RT-PCR were performed to study mechanisms underlying the action of SEPJ.

RESULTS

SEPJ inhibited TGF-β-induced EMT in AML-12 hepatocytes and activation of LX-2 HSCs. SEPJ elevated Akt phosphorylation at Ser473 and GSK3β phosphorylation at Ser9 in these cells, giving rise to a descent of the catalytic activity of GSK3β. These events increased levels of both total and nuclear Nrf2 protein and upregulated expressions of Nrf2-responsive antioxidative genes. In addition, enhanced phosphorylation of Akt and GSK3β acted upstream of SEPJ-mediated activation of Nrf2. Knockdown of Nrf2 or inhibition of Akt diminished the protective activity of SEPJ against TGF-β in both AML-12 and LX-2 cells. Our further in vivo experiments revealed that SEPJ imposed a considerable alleviation on CCl₄-provoked mouse liver fibrosis. Moreover, hepatic Akt/GSK3β/Nrf2 cascade were potentiated by SEPJ. Taken together, our results unveiled that SEPJ exerted protective effects against fibrogenic cytokine TGF-β in vitro and ameliorated liver fibrosis in mice. Mechanistically, SEPJ regulated the Akt/GSK3β/Nrf2 signaling which subsequently enhanced intracellular antioxidative capacity.

CONCLUSIONS

SEPJ inhibits hepatocyte EMT and HSC activation in vitro and alleviates liver fibrosis in mice. Modulation of the Akt/GSK3β/Nrf2 cascade attributes to its hepatoprotective effects. Our findings support a possible application of SEPJ in the control of liver fibrosis.

NORAD lentivirus shRNA mitigates fibrosis and inflammatory responses in diabetic cardiomyopathy via the ceRNA network of NORAD/miR-125a-3p/Fyn

OBJECTIVE

Diabetic cardiomyopathy (DCM) is a serious complication of diabetes, but its pathogenesis is still unclear. This study investigated the mechanism of long noncoding RNA (lncRNA) NORAD in DCM.

METHODS

Male leptin receptor-deficient (db/db) mice and leptin control mice (db/ +) were procured. DCM model was established by subcutaneous injection of angiotensin II (ATII) in db/db mice. NORAD lentivirus shRNA or Adv-miR-125a-3p was administered to analyze cardiac function, fibrosis, serum biochemical indexes, inflammation and fibrosis. Primary cardiomyocytes were extracted and transfected with miR-125a-3p mimic. The competing endogenous RNA (ceRNA) network of NORAD/miR-125a-3p/Fyn was verified. The levels of fibrosis- and inflammation-related factors were measured.

RESULTS

In db/db mice treated with ATII, the body weight and serum biochemical indexes were increased, while the cardiac function was decreased, and inflammatory cell infiltration and fibrosis were induced. NORAD was upregulated in diabetic and DCM mice. The 4-week intravenous injection of NORAD lentivirus shRNA reduced body weight and serum biochemical indexes, improved cardiac function, and attenuated inflammation and fibrosis in DCM mice. NORAD acted as a sponge to adsorb miR-125a-3p, and miR-125a-3p targeted Fyn. Intravenous injection of miR-125a-3p adenovirus improved cardiac function and fibrosis and reduced inflammatory responses in DCM mice. Co-overexpression of miR-125-3p and Fyn partly reversed the improving effect of miR-125-3p overexpression on cardiac fibrosis in DCM mice.

CONCLUSION

NORAD lentivirus shRNA improved cardiac function and fibrosis and reduced inflammatory responses in DCM mice via the ceRNA network of NORAD/miR-125a-3p/Fyn. These findings provide a valuable and promising therapeutic target for the treatment of DCM.

Cyclometalated Ru(II)-isoquinoline complexes overcome cisplatin resistance of A549/DDP cells by downregulation of Nrf2 via Akt/GSK-3β/Fyn pathway

Both ruthenium (Ru) and isoquinoline (IQ) compounds are regarded as potential anticancer drug candidates. Here, we report the synthesis and characterization of three novel cyclometalated Ru(II)-isoquinoline complexes: RuIQ-3, RuIQ-4, and RuIQ-5, and evaluation of their in vitro cytotoxicities against a panel of cell lines including A549/DDP, a cisplatin-resistant human lung cancer cell line. A549/DDP 3D multicellular tumor spheroids (MCTSs) were also used to detect the drug resistance reversal effect of Ru(II)-IQ complexes. Our results indicated that the cytotoxic activities against cancer cells of Ru(II)-IQ complexes, especially RuIQ-5, were superior compared with cisplatin. In addition, RuIQ-5 exhibited low toxicity towards both normal HBE cells in vitro and zebrafish embryos in vivo. Further investigation on cellular mechanism of action indicated that after absorption by A549/DDP cells, RuIQ-5 was mainly distributed in the nucleus, which is different from cisplatin. Besides, RuIQ-5 could induce apoptosis through mitochondrial dysfunction, reactive oxygen species (ROS) accumulation, ROS-mediated DNA damage, and cycle arrest at both S and G2/M phases. Moreover, RuIQ-5 could inhibit the overexpression of Nrf2 through regulation of Akt/GSK-3β/Fyn signaling pathway and hindering the nuclear translocation of Nrf2. Based on these findings, we firmly believe that the studied Ru(II)-IQ complexes hold great promise as anticancer therapeutics with high effectiveness and low toxicity.

Bioactive Compounds in Oxidative Stress-Mediated Diseases: Targeting the NRF2/ARE Signaling Pathway and Epigenetic Regulation

Oxidative stress is a pathological condition occurring due to an imbalance between the oxidants and antioxidant defense systems in the body. Nuclear factor E2-related factor 2 (NRF2), encoded by the gene NFE2L2, is the master regulator of phase II antioxidant enzymes that protect against oxidative stress and inflammation. NRF2/ARE signaling has been considered as a promising target against oxidative stress-mediated diseases like diabetes, fibrosis, neurotoxicity, and cancer. The consumption of dietary phytochemicals acts as an effective modulator of NRF2/ARE in various acute and chronic diseases. In the present review, we discussed the role of NRF2 in diabetes, Alzheimer's disease (AD), Parkinson's disease (PD), cancer, and atherosclerosis. Additionally, we discussed the phytochemicals like curcumin, quercetin, resveratrol, epigallocatechin gallate, apigenin, sulforaphane, and ursolic acid that have effectively modified NRF2 signaling and prevented various diseases in both in vitro and in vivo models. Based on the literature, it is clear that dietary phytochemicals can prevent diseases by (1) blocking oxidative stress-inhibiting inflammatory mediators through inhibiting Keap1 or activating Nrf2 expression and its downstream targets in the nucleus, including HO-1, SOD, and CAT; (2) regulating NRF2 signaling by various kinases like GSK3beta, PI3/AKT, and MAPK; and (3) modifying epigenetic modulation, such as methylation, at the NRF2 promoter region; however, further investigation into other upstream signaling molecules like NRF2 and the effect of phytochemicals on them still need to be investigated in the near future.

mTOR inhibitor PP242 increases antitumor activity of sulforaphane by blocking Akt/mTOR pathway in esophageal squamous cell carcinoma

BACKGROUND

Sulforaphane (SFN) is a kind of isothiocyanate from cruciferous vegetables with extensive anti-tumor activity. Esophageal squamous cell carcinoma (ESCC) is a popular malignancy in East Asia, East and South Africa, while the more efficient medicines and therapeutic strategies are still lack. This study aims to explore the anti-tumor activity of SFN alone and combined with Akt/mTOR pathway inhibitors as well as the potential molecular mechanism in ESCC.

METHODS AND RESULTS

Cell proliferation, migration, cell cycle phase, apoptosis and protein expression were detected with MTT assay, clone formation experiment, wound healing assays, flow cytometry and Western blot, respectively, after ESCC cells ECa109 and EC9706 treated with SFN alone or combined with Akt/mTOR inhibitors. Xenograft models were used to evaluate the efficiency and mechanism of SFN combined with PP242 in vivo. The results showed that SFN significantly inhibited the viability and induced apoptosis of ECa109 and EC9706 cells by increasing expression of Cleaved-caspase 9. SFN combined with PP242, but not MK2206 and RAD001, synergetic inhibited proliferation of ESCC cells. Moreover, compared to SFN alone, combination of SFN and PP242 had stronger inhibiting efficiency on clone formation, cell migratory, cell cycle phase and growth of xenografts, as well as the more powerful apoptosis-inducing effects on ESCC. The mechanism was that PP242 abrogated the promoting effects of SFN on p-p70S6K (Thr389) and p-Akt (Ser473) in ESCC.

CONCLUSIONS

Our findings demonstrate that PP242 enhances the anti-tumor activity of SFN by blocking SFN-induced activation of Akt/mTOR pathway in ESCC, which provides a rationale for treating ESCC using SFN combined with Akt/mTOR pathway inhibitors.

PHLDA3 inhibition protects against myocardial ischemia/reperfusion injury by alleviating oxidative stress and inflammatory response via the Akt/Nrf2 axis

Pleckstrin homology-like domain family A, member 3 (PHLDA3) has a particularly critical role in regulating cell survival under stress conditions. However, whether PHLDA3 plays a role in myocardial ischemia/reperfusion injury has not been studied. We aimed to assess the possible role of PHLDA3 in myocardial ischemia/reperfusion (I/R) injury. PHLDA3 expression was increased in myocardial tissue from rats with myocardial I/R injury and rat cardiomyocytes with hypoxia/reoxygenation (H/R) injury. PHLDA3 knockdown protected against myocardial I/R injury in vivo and H/R injury in vitro. Inhibition of PHLDA3 increased the activation of nuclear factor erythroid-derived 2-related factor 2 (Nrf2) associated with regulation of the Akt/glycogen synthase kinase-3β (GSK-3β) axis. Repression of Nrf2 reversed PHLDA3-inhibition-mediated cardioprotective effects. Taken together, our work demonstrates that PHLDA3 inhibition exerts a protective role in myocardial I/R injury via regulation of the Akt/GSK-3β/Nrf2 axis. We suggest PHLDA3 as an attractive target for developing treatments against myocardial I/R injury.

AGE-Rich Bread Crust Extract Boosts Oxidative Stress Interception via Stimulation of the NRF2 Pathway

Advanced glycation end products (AGEs) result from a non-enzymatic reaction of proteins with reactive carbohydrates. Heat-processed food, such as bread, contains high amounts of AGEs. The activation of the NF-κB signaling pathway by bread crust extract (BCE) is well understood. However, it is largely unknown whether NRF2, the master regulator of oxidative stress resistance in mammalian cells, is affected by BCE. We have investigated the molecular mechanisms by which BCE induces antioxidant gene expression in cellular models. Our data showed that soluble extracts from bread crust are capable of stimulating the NRF2 signaling pathway. Furthermore, NRF2 pathway activation was confirmed by microarray and reporter-cell analyses. QRT-PCR measurements and Western blot analyses indicated an induction of antioxidative genes such as HMOX1, GCLM and NQO1 upon BCE treatment. Moreover, BCE pretreated cells had a survival advantage compared to control cells when exposed to oxidative stress. BCE induces phosphorylation of AKT and ERK kinase in EA.hy926 cells. By mass spectrometry, several new, potentially active modifications in BCE were identified. Our findings indicate that BCE activates NRF2-dependent antioxidant gene expression, thus provoking a protection mechanism against oxidative stress-mediated tissue injury. Hence, BCE can be considered as functional food with antioxidative and cardioprotective potential.

NRF2 Activation and Downstream Effects: Focus on Parkinson's Disease and Brain Angiotensin

Reactive oxygen species (ROS) are signalling molecules used to regulate cellular metabolism and homeostasis. However, excessive ROS production causes oxidative stress, one of the main mechanisms associated with the origin and progression of neurodegenerative disorders such as Parkinson's disease. NRF2 (Nuclear Factor-Erythroid 2 Like 2) is a transcription factor that orchestrates the cellular response to oxidative stress. The regulation of NRF2 signalling has been shown to be a promising strategy to modulate the progression of the neurodegeneration associated to Parkinson's disease. The NRF2 pathway has been shown to be affected in patients with this disease, and activation of NRF2 has neuroprotective effects in preclinical models, demonstrating the therapeutic potential of this pathway. In this review, we highlight recent advances regarding the regulation of NRF2, including the effect of Angiotensin II as an endogenous signalling molecule able to regulate ROS production and oxidative stress in dopaminergic neurons. The genes regulated and the downstream effects of activation, with special focus on Kruppel Like Factor 9 (KLF9) transcription factor, provide clues about the mechanisms involved in the neurodegenerative process as well as future therapeutic approaches.

An Insight on Multicentric Signaling of Angiotensin II in Cardiovascular system: A Recent Update

The multifaceted nature of the renin-angiotensin system (RAS) makes it versatile due to its involvement in pathogenesis of the cardiovascular disease. Angiotensin II (Ang II), a multifaceted member of RAS family is known to have various potential effects. The knowledge of this peptide has immensely ameliorated after meticulous research for decades. Several studies have evidenced angiotensin I receptor (AT1 R) to mediate the majority Ang II-regulated functions in the system. Functional crosstalk between AT1 R mediated signal transduction cascades and other signaling pathways has been recognized. The review will provide an up-to-date information and recent discoveries involved in Ang II receptor signal transduction and their functional significance in the cardiovascular system for potential translation in therapeutics. Moreover, the review also focuses on the role of stem cell-based therapies in the cardiovascular system.

κ Opioid Receptor Agonist Inhibits Myocardial Injury in Heart Failure Rats through Activating Nrf2/HO-1 Pathway and Regulating Ca2+-SERCA2a

OBJECTIVES

We aimed to observe the protective effect of κ opioid receptor (κ-OR) agonist on myocardial injury in heart failure (HF) rats and its effect on Ca2+-SERCA2a and to explore the regulatory mechanism with the Nrf2/HO-1 signaling pathway.

METHODS

50 Sprague-Dawley rats were randomly divided into the following groups: the sham operation group (sham group), HF model group (HF group), HF+κ-OR agonist U50488 group (HU group), HF+U50488H+novel calmodulin-dependent protein kinase II (CaMKII) agonist (oleic acid) (HUO group), and HF+U50488H+Nrf2 inhibitor (HUM group). The HF rat's model was established through surgical ligation of the left anterior descending coronary artery and the exhausting swimming exercise. After that, rat's cardiac function was monitored by echocardiography. HE and MASSON staining was used to detect the myocardial injury, and TUNEL staining was used to detect the myocardial apoptosis. ELISA was performed to detect the biomarkers of oxidative stress. Moreover, the distribution of reactive oxygen species (ROS) and Nrf2 was detected under immunofluorescence. The expression of sarco/endoplasmic reticulum calcium (Ca2+) ATPase (SERCA) 2a, calmodulin, endoplasmic reticulum stress- (ERS-) related proteins, and Nrf2/HO-1 signaling pathway-related proteins were detected by Western Blotting.

RESULTS

κ-OR agonist U50488H can significantly enhance rat's cardiac function, reduce the injury and apoptosis of myocardial cells, and alleviate endoplasmic reticulum stress injury in HF rats via upregulating the SERCA2a expression and inhibiting the Ca2+ influx. Furthermore, U50488H could also inhibit the phosphorylation of CaMKII and cAMP-response element binding protein (CREB). Additionally, administration of CaMKII-specific agonist could partially block the therapeutic effect of κ-OR agonist on the myocardium of HF rats. Interestingly, the antagonist of Nrf2 could also significantly reverse the therapeutic effect of κ-OR agonist. Therefore, these results suggested that the effect of U50488H on HF rats is dependent on regulating CaMKII phosphorylation and activating the Nrf2/HO-1 pathway.

CONCLUSION

κ-OR agonists U50488H can improve ERS in cardiomyocytes and relieve myocardial injury in HF rats through activating the Nrf2/HO-1 pathway and regulating Ca2+-SERCA2a to inhibit Ca2+ influx.

Nrf2 for cardiac protection: pharmacological options against oxidative stress

Myocardial ischemia or reperfusion increases the generation of reactive oxygen species (ROS) from damaged mitochondria, NADPH oxidases, xanthine oxidase, and inflammation. ROS can be removed by eight endogenous antioxidant and redox systems, many components of which are expressed under the influence of the activated Nrf2 transcription factor. Transcriptomic profiling, sequencing of Nrf2-bound DNA, and Nrf2 gene knockout studies have revealed the power of Nrf2 beyond the antioxidant and detoxification response, from tissue recovery, repair, and remodeling, mitochondrial turnover, and metabolic reprogramming to the suppression of proinflammatory cytokines. Multifaceted regulatory mechanisms for Nrf2 protein levels or activity have been mapped to its functional domains, Nrf2-ECH homology (Neh)1-7. Oxidative stress activates Nrf2 via nuclear translocation, de novo protein translation, and increased protein stability due to removal of the Kelch-like ECH-associated protein 1 (Keap1) checkpoint, or the inactivation of β-transducin repeat-containing protein (β-TrCP), or Hmg-CoA reductase degradation protein 1 (Hrd1). The promise of small-molecule Nrf2 inducers from natural products or derivatives is discussed here. Experimental evidence is presented to support Nrf2 as a lead target for drug development to further improve the treatment outcome for myocardial infarction (MI).

Sulforaphane: A review of its therapeutic potentials, advances in its nanodelivery, recent patents, and clinical trials

Traditionally, herbal supplements have shown an exceptional potential of desirability for the prevention of diseases and their treatment. Sulforaphane (SFN), an organosulfur compound belongs to the isothiocyanate (ITC) group and is mainly found naturally in cruciferous vegetables. Several studies have now revealed that SFN possesses broad spectrum of activities and has shown extraordinary potential as antioxidant, antitumor, anti-angiogenic, and anti-inflammatory agent. In addition, SFN is proven to be less toxic, non-oxidizable, and its administration to individuals is well tolerated, making it an effective natural dietary supplement for clinical trials. SFN has shown its ability to be a promising future drug molecule for the management of various diseases mainly due to its potent antioxidant properties. In recent times, several newer drug delivery systems were designed and developed for this potential molecule in order to enhance its bioavailability, stability, and to reduce its side effects. This review focuses to cover numerous data supporting the wide range of pharmacological activities of SFN, its drug-related issues, and approaches to improve its physicochemical and biological properties, including solubility, stability, and bioavailability. Recent patents and the ongoing clinical trials on SFN are also summarized.

Aldosterone Negatively Regulates Nrf2 Activity: An Additional Mechanism Contributing to Oxidative Stress and Vascular Dysfunction by Aldosterone

High levels of aldosterone (Aldo) trigger oxidative stress and vascular dysfunction independent of effects on blood pressure. We sought to determine whether Aldo disrupts Nrf2 signaling, the main transcriptional factor involved in antioxidant responses that aggravate cell injury. Thoracic aorta from male C57Bl/6J mice and cultured human endothelial cells (EA.hy926) were stimulated with Aldo (100 nM) in the presence of tiron [reactive oxygen species (ROS) scavenger, eplerenone [mineralocorticoid receptor (MR) antagonist], and L-sulforaphane (SFN; Nrf2 activator). Thoracic aortas were also isolated from mice infused with Aldo (600 μg/kg per day) for 14 days. Aldo decreased endothelium-dependent vasorelaxation and increased ROS generation, effects prevented by tiron and MR blockade. Pharmacological activation of Nrf2 with SFN abrogated Aldo-induced vascular dysfunction and ROS generation. In EA.hy926 cells, Aldo increased ROS generation, which was prevented by eplerenone, tiron, and SFN. At short times, Aldo-induced ROS generation was linked to increased Nrf2 activation. However, after three hours, Aldo decreased the nuclear accumulation of Nrf2. Increased Keap1 protein expression, but not activation of p38 MAPK, was linked to Aldo-induced reduced Nrf2 activity. Arteries from Aldo-infused mice also exhibited decreased nuclear Nrf2 and increased Keap1 expression. Our findings suggest that Aldo reduces vascular Nrf2 transcriptional activity by Keap1-dependent mechanisms, contributing to mineralocorticoid-induced vascular dysfunction.

Polydatin has anti-inflammatory and antioxidant effects in LPS-induced macrophages and improves DSS-induced mice colitis

Polydatin (PD), a monocrystalline compound isolated from the root and rhizome of Polygonum cuspidatum, is widely used in inhibiting the inflammatory response and oxidative stress. PD has an anti‐inflammatory effect on colitis mice; however, information regulating the mechanism by which maintains the intestinal epithelium barrier is currently scarce. Here, we assessed the anti‐inflammatory and antioxidant of PD in lipopolysaccharide (LPS)‐induced macrophages in vitro, and explored its effects on inhibiting intestinal inflammation and maintaining the intestinal epithelium barrier in dextran sodium sulfate (DSS)‐induced colitis mice. Results showed that PD reduced the level of proinflammatory cytokines and enzymes, including tumor necrosis factor‐α, interleukin‐4 (IL‐4), IL‐6, cyclooxygenase‐2, and inducible nitric oxide synthase, in LPS‐induced macrophages, and improved the expression level of IL‐10. PD maintained the expression of tight junction proteins in medium (LPS‐induced macrophages medium)‐induced MCEC cells. Additionally, PD inhibited the phosphorylation of nuclear factor‐κB (NF‐κB), p65, extracellular signal‐regulated kinase‐1/2, c‐Jun N‐terminal kinase, and p38 signaling pathways in LPS‐induced macrophages and facilitated the phosphorylation of AKT and the nuclear translocation of Nrf2, improving the expression of HO‐1 and NQO1. Furthermore, PD ameliorated the intestinal inflammatory response and improved the dysfunction of the colon epithelium barrier in DSS‐induced colitis mice. Taken together, our results indicated that PD inhibited inflammation and oxidative stress, maintained the intestinal epithelium barrier, and the protective role of PD was associated with the NF‐κB p65, itogen‐activated protein kinases, and AKT/Nrf2/HO‐1/NQO1 signaling pathway.

MicroRNA-200c Prevents Progress of Cutaneous Squamous Cell Carcinoma by Targeting Tyrosine-Protein Kinase Fyn (FYN)

Cutaneous squamous cell carcinoma (cSCC), a malignant skin tumor, begins in the epidermis and the keratinocytes of the skin appendages. However, the cause remains unclear. MicroRNA-200c (miR-200c), a key modulator of epithelial-to-mesenchymal transition (EMT), has been reported to act as an anticancer gene in a variety of cancers. However, its role and partial mechanism in cSCC remain undetermined. The results of this study showed depleted levels of miR-200c in cSCC tissues. Its suppressive effects on cell proliferation, and motility, as well as its apoptosis-promoting effect, were observed in the A-431 cells. Additionally, immunofluorescence and qRT-PCR assays revealed that FYN acted as a direct target of miR-200c, and FYN knockdown exerted had similar impact as that of miR-200c overexpression, including increased cellular apoptosis and decreased cellular growth. These results emphasized the onco-suppressive nature of miR-200c, which was evident based on its interaction with FYN in cSCC. This finding could have potential benefits in developing cSCC therapy.

A review on herbal Nrf2 activators with preclinical evidence in cardiovascular diseases

Cardiovascular diseases (CVDs) are an ever-growing problem and are the most common cause of death worldwide. The uncontrolled production of reactive oxygen species (ROS) and the activation of ROS associated with various cell signaling pathways with oxidative cellular damage are the most common pathological conditions connected with CVDs including endothelial dysfunction, hypercontractility of vascular smooth muscle, cardiac hypertrophy and heart failure. The nuclear factor E2-related factor 2 (Nrf2) is a basic leucine zipper redox transcription factor, together with its negative regulator, kelch-like ECH-associated protein 1 (Keap1), which serves as a key regulator of cellular defense mechanisms to combat oxidative stress and associated diseases. Multiple lines of evidence described here support the cardiac protective property of Nrf2 in various experimental models of cardiac related disease conditions. In this review, we emphasized the molecular mechanisms of Nrf2 and described the detailed outline of current findings on the therapeutic possibilities of the Nrf2 activators specifically from herbal origin in various CVDs. Based on evidence from various preclinical experimental models, we have highlighted the activation of Nrf2 pathway as a budding therapeutic option for the prevention and treatment of CVDs, which needs further investigation and validation in the clinical settings.

The Keap1-Nrf2 System: A Mediator between Oxidative Stress and Aging

Oxidative stress, a term that describes the imbalance between oxidants and antioxidants, leads to the disruption of redox signals and causes molecular damage. Increased oxidative stress from diverse sources has been implicated in most senescence-related diseases and in aging itself. The Kelch-like ECH-associated protein 1- (Keap1-) nuclear factor-erythroid 2-related factor 2 (Nrf2) system can be used to monitor oxidative stress; Keap1-Nrf2 is closely associated with aging and controls the transcription of multiple antioxidant enzymes. Simultaneously, Keap1-Nrf2 signaling is also modulated by a more complex regulatory network, including phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt), protein kinase C, and mitogen-activated protein kinase. This review presents more information on aging-related molecular mechanisms involving Keap1-Nrf2. Furthermore, we highlight several major signals involved in Nrf2 unbinding from Keap1, including cysteine modification of Keap1 and phosphorylation of Nrf2, PI3K/Akt/glycogen synthase kinase 3β, sequestosome 1, Bach1, and c-Myc. Additionally, we discuss the direct interaction between Keap1-Nrf2 and the mammalian target of rapamycin pathway. In summary, we focus on recent progress in research on the Keap1-Nrf2 system involving oxidative stress and aging, providing an empirical basis for the development of antiaging drugs.

Extracellular vesicle microRNA cargoes from intermittent hypoxia-exposed cardiomyocytes and their effect on endothelium

Intermittent hypoxia (IH), a main characteristic of obstructive sleep apnea (OSA) syndrome, is an independent risk factor of cardiovascular complications. However, the mechanism has not been fully elucidated. Growing evidence has revealed alterations of extracellular vesicle (EV) contents, mostly miRNAs, playing a pathogenic role in cardiovascular complications. In current study, we attempt to compare the disparity of myocardial EV miRNA components after IH or normoxia treatment and determine whether EVs from IH-treated cardiomyocytes could affect endothelial function. 63 differentially expressed miRNAs were identified in EVs from IH-exposed cardiomyocytes by miRNA chip assay. Among them, 16 miRNAs with homologous sequence in mouse and human were verified by qPCR assay and 11 miRNAs were proved with the same tendency as miRNA chip assay. KEGG predicted that the function of differentially expressed miRNA was enriched to Akt signaling pathway. Notably, EVs from IH-exposed cardiomyocytes dramatically impaired endothelial-dependent relaxation and inhibited Akt/eNOS expression in endothelial cells. This study provides the first evidence that IH significantly alters myocardial EV miRNA composition and reveals a novel role of myocardial EVs in endothelial function under IH status, which will help to understand the OSA- or IH-related endothelial dysfunction from a new scope.

Combined treatment with ultrasound-targeted microbubble destruction technique and NM-aFGF-loaded PEG-nanoliposomes protects against diabetic cardiomyopathy-induced oxidative stress by activating the AKT/GSK-3β1/Nrf-2 pathway

The present study sought to investigate the effect of non-mitogenic acidic fibroblast growth factor (NM-aFGF) loaded PEGylated nanoliposomes (NM-aFGF-PEG-lips) combined with the ultrasound-targeted microbubble destruction (UTMD) technique on modulating diabetic cardiomyopathy (DCM)and the mechanism involved. Animal studies showed that the diabetes mellitus (DM) group exhibited typical myocardial structural and functional changes of DCM. The indexes from the transthoracic echocardiography showed that the left ventricular function in the NM-aFGF-PEG-lips + UTMD group was significantly improved compared with the DM group. Histopathological observation further confirmed that the cardiomyocyte structural abnormalities and mitochondria ultrastructural changes were also significantly improved in the NM-aFGF-PEG-lips + UTMD group compared with DM group. The cardiac volume fraction (CVF) and apoptosis index in the NM-aFGF-PEG-lips + UTMD group decreased to 10.31 ± 0.76% and 2.16 ± 0.34, respectively, compared with those in the DM group (CVF = 21.4 ± 2.32, apoptosis index = 11.51 ± 1.24%). Moreover, we also found significantly increased superoxide dismutase (SOD) activity and glutathione peroxidase (GSH-Px) activity as well as clearly decreased lipid hydroperoxide levels and malondialdehyde (MDA) activity in the NM-aFGF-PEG-lips + UTMD group compared with those in the DM group (p < .05). Western blot analysis further revealed the highest level of NM-aFGF, p-AKT, p-GSK-3β1, Nrf-2, SOD2 and NQO1 in the NM-aFGF-PEG-lips + UTMD group. This study confirmed using PEGylated nanoliposomes combined with the UTMD technique can effectively deliver NM-aFGF to the cardiac tissue of diabetic rats. The NM-aFGF can then inhibit myocardial oxidative stress damage due to DM by activating the AKT/GSK/Nrf-2 signaling pathway, which ultimately improved the myocardial structural and functional lesions in diabetic rats.

Sulforaphane prevents angiotensin II-induced cardiomyopathy by activation of Nrf2 through epigenetic modification

Nuclear factor erythroid 2-related factor (Nrf2) is an important regulator of cellular antioxidant defence. We previously showed that SFN prevented Ang II-induced cardiac damage via activation of Nrf2. However, the underlying mechanism of SFN's persistent cardiac protection remains unclear. This study aimed to explore the potential of SFN in activating cardiac Nrf2 through epigenetic mechanisms. Wild-type mice were injected subcutaneously with Ang II, with or without SFN. Administration of chronic Ang II-induced cardiac inflammatory factor expression, oxidative damage, fibrosis and cardiac remodelling and dysfunction, all of which were effectively improved by SFN treatment, coupled with an up-regulation of Nrf2 and downstream genes. Bisulfite genome sequencing and chromatin immunoprecipitation (ChIP) were performed to detect the methylation level of the first 15 CpGs and histone H3 acetylation (Ac-H3) status in the Nrf2 promoter region, respectively. The results showed that SFN reduced Ang II-induced CpG hypermethylation and promoted Ac-H3 accumulation in the Nrf2 promoter region, accompanied by the inhibition of global DNMT and HDAC activity, and a decreased protein expression of key DNMT and HDAC enzymes. Taken together, SFN exerts its cardioprotective effect through epigenetic modification of Nrf2, which may partially contribute to long-term activation of cardiac Nrf2.

Cardiac Protective Effect of Kirenol against Doxorubicin-Induced Cardiac Hypertrophy in H9c2 Cells through Nrf2 Signaling via PI3K/AKT Pathways

Kirenol (KRL) is a biologically active substance extracted from Herba Siegesbeckiae. This natural type of diterpenoid has been widely adopted for its important anti-inflammatory and anti-rheumatic properties. Despite several studies claiming the benefits of KRL, its cardiac effects have not yet been clarified. Cardiotoxicity remains a key concern associated with the long-term administration of doxorubicin (DOX). The generation of reactive oxygen species (ROS) causes oxidative stress, significantly contributing to DOX-induced cardiac damage. The purpose of the current study is to investigate the cardio-protective effects of KRL against apoptosis in H9c2 cells induced by DOX. The analysis of cellular apoptosis was performed using the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining assay and measuring the modulation in the expression levels of proteins involved in apoptosis and Nrf2 signaling, the oxidative stress markers. Furthermore, Western blotting was used to determine cell survival. KRL treatment, with Nrf2 upregulation and activation, accompanied by activation of PI3K/AKT, could prevent the administration of DOX to induce cardiac oxidative stress, remodeling, and other effects. Additionally, the diterpenoid enhanced the activation of Bcl2 and Bcl-xL, while suppressing apoptosis marker proteins. As a result, KRL is considered a potential agent against hypertrophy resulting from cardiac deterioration. The study results show that KRL not only activates the IGF-IR-dependent p-PI3K/p-AKT and Nrf2 signaling pathway, but also suppresses caspase-dependent apoptosis.

Application of Animal Models in Diabetic Cardiomyopathy

Diabetic heart disease is a growing and important public health risk. Apart from the risk of coronary artery disease or hypertension, diabetes mellitus (DM) is a well-known risk factor for heart failure in the form of diabetic cardiomyopathy (DiaCM). Currently, DiaCM is defined as myocardial dysfunction in patients with DM in the absence of coronary artery disease and hypertension. The underlying pathomechanism of DiaCM is partially understood, but accumulating evidence suggests that metabolic derangements, oxidative stress, increased myocardial fibrosis and hypertrophy, inflammation, enhanced apoptosis, impaired intracellular calcium handling, activation of the renin-angiotensin-aldosterone system, mitochondrial dysfunction, and dysregulation of microRNAs, among other factors, are involved. Numerous animal models have been used to investigate the pathomechanisms of DiaCM. Despite some limitations, animal models for DiaCM have greatly advanced our understanding of pathomechanisms and have helped in the development of successful disease management strategies. In this review, we summarize the current pathomechanisms of DiaCM and provide animal models for DiaCM according to its pathomechanisms, which may contribute to broadening our understanding of the underlying mechanisms and facilitating the identification of possible new therapeutic targets.

The protective effects of fibroblast growth factor 10 against hepatic ischemia-reperfusion injury in mice

Hepatic ischemia-reperfusion injury (IRI) is a major complication of liver surgery and transplantation. IRI leads to hepatic parenchymal cell death, resulting in liver failure, and lacks effective therapeutic approaches. Fibroblast growth factor 10 (FGF10) is a paracrine factor which is well-characterized with respect to its pro-proliferative effects during embryonic liver development and liver regeneration, but its role in hepatic IRI remains unknown. In this study, we investigated the role of FGF10 in liver IRI and identified signaling pathways regulated by FGF10. In a mouse model of warm liver IRI, FGF10 was highly expressed during the reperfusion phase. In vitro experiments demonstrated that FGF10 was primarily secreted by hepatic stellate cells and acted on hepatocytes. The role of FGF10 in liver IRI was further examined using adeno-associated virus-mediated gene silencing and overexpression. Overexpression of FGF10 alleviated liver dysfunction, reduced necrosis and inflammation, and protected hepatocytes from apoptosis in the early acute injury phase of IRI. Furthermore, in the late phase of IRI, FGF10 overexpression also promoted hepatocyte proliferation. Meanwhile, gene silencing of FGF10 had the opposite effect. Further studies revealed that overexpression of FGF10 activated nuclear factor-erythroid 2-related factor 2 (NRF2) and decreased oxidative stress, mainly through activation of the phosphatidylinositol-3-kinase/AKT pathway, and the protective effects of FGF10 overexpression were largely abrogated in NRF2 knockout mice. These results demonstrate the protective effects of FGF10 in liver IRI, and reveal the important role of NRF2 in FGF10-mediated hepatic protection during IRI.

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FGF10 is markedly upregulated in the early phase of liver IRI.

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FGF10 overexpression exerts great potential in ameliorating hepatic IRI.

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FGF10 knockdown significantly aggravates hepatic IRI.

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FGF10 overexpression activates PI3K/AKT-NRF2 signaling and thus ameliorates hepatic IRI.

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NRF2 knockout abrogates the protective effects of FGF10 overexpression during liver IRI.

Activated PKB/GSK-3β synergizes with PKC-δ signaling in attenuating myocardial ischemia/reperfusion injury via potentiation of NRF2 activity: Therapeutic efficacy of dihydrotanshinone-I

Disrupted redox status primarily contributes to myocardial ischemia/reperfusion injury (MIRI). NRF2, the endogenous antioxidant regulator, might provide therapeutic benefits. Dihydrotanshinone-I (DT) is an active component in Salvia miltiorrhiza with NRF2 induction potency. This study seeks to validate functional links between NRF2 and cardioprotection of DT and to investigate the molecular mechanism particularly emphasizing on NRF2 cytoplasmic/nuclear translocation. DT potently induced NRF2 nuclear accumulation, ameliorating post-reperfusion injuries via redox alterations. Abrogated cardioprotection in NRF2-deficient mice and cardiomyocytes strongly supports NRF2-dependent cardioprotection of DT. Mechanistically, DT phosphorylated NRF2 at Ser40, rendering its nuclear-import by dissociating from KEAP1 and inhibiting degradation. Importantly, we identified PKC-δ-(Thr505) phosphorylation as primary upstream event triggering NRF2-(Ser40) phosphorylation. Knockdown of PKC-δ dramatically retained NRF2 in cytoplasm, convincing its pivotal role in mediating NRF2 nuclear-import. NRF2 activity was further enhanced by activated PKB/GSK-3β signaling via nuclear-export signal blockage independent of PKC-δ activation. By demonstrating independent modulation of PKC-δ and PKB/GSK-3β/Fyn signaling, we highlight the ability of DT to exploit both nuclear import and export regulation of NRF2 in treating reperfusion injury harboring redox homeostasis alterations. Coactivation of PKC and PKB phenocopied cardioprotection of DT in vitro and in vivo, further supporting the potential applicability of this rationale.

Efficacy of broccoli and glucoraphanin in COVID-19: From hypothesis to proof-of-concept with three experimental clinical cases

COVID-19 is described in a clinical case involving a patient who proposed the hypothesis that Nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-interacting nutrients may help to prevent severe COVID-19 symptoms. Capsules of broccoli seeds containing glucoraphanin were being taken before the onset of SARS-CoV-2 infection and were continued daily for over a month after the first COVID-19 symptoms. They were found to reduce many of the symptoms rapidly and for a duration of 6-12 h by repeated dosing. When the patient was stable but still suffering from cough and nasal obstruction when not taking the broccoli capsules, a double-blind induced cough challenge confirmed the speed of onset of the capsules (less than 10 min). A second clinical case with lower broccoli doses carried out during the cytokine storm confirmed the clinical benefits already observed. A third clinical case showed similar effects at the onset of symptoms. In the first clinical trial, we used a dose of under 600 μmol per day of glucoraphanin. However, such a high dose may induce pharmacologic effects that require careful examination before the performance of any study. It is likely that the fast onset of action is mediated through the TRPA1 channel. These experimental clinical cases represent a proof-of-concept confirming the hypothesis that Nrf2-interacting nutrients are effective in COVID-19. However, this cannot be used in practice before the availability of further safety data, and confirmation is necessary through proper trials on efficacy and safety.

AT1R/GSK-3β/mTOR Signaling Pathway Involved in Angiotensin II-Induced Neuronal Apoptosis after HIE Both In Vitro and In Vivo

Objective

The focus of the present study is to evaluate the effects of Angiotensin II (Ang II) on neuronal apoptosis after HIE and the potential underlying mechanisms.

Methods

Primary neonatal rat cortical neurons were used to study the oxygen-glucose deprivation (OGD) cell model. The expressions of Ang II, AT1R, GSK-3β, p-GSK-3β, mTOR, p-mTOR, Bax, Bcl-2, and cleaved caspase-3 were detected via western blot. IF and flow cytometry were used to evaluate neuronal apoptosis. Hypoxic-ischemic encephalopathy (HIE) was established to evaluate the therapeutic effects of Ang II in vivo. Cerebral infarction areas were detected by 2,3,5-Triphenyltetrazolium chloride staining. The righting and geotaxis reflexes were also recorded. In addition, Fluoro-Jade C staining and TUNEL staining were performed to evaluate neuronal degeneration and apoptosis.

Results

Ang II significantly increased the rate of neuronal apoptosis, upregulated the expression of cleaved caspase-3, and downregulated Bcl-2/Bax ratio after OGD insult. For vivo assay, the expressions of endogenous Ang II and AT1R gradually increased and peaked at 24 h after HIE. Ang II increased NeuN-positive AT1R cell expression. In addition, Ang II increased the area of cerebral infarction, promoted neuronal degeneration and apoptosis, aggravated neurological deficits on righting and geotaxis reflexes, and was accompanied by increased expressions of phosphorylated GSK-3β and mTOR. The application of valsartan (Ang II inhibitor) or SB216763 (GSK-3β inhibitor) reversed these phenomena triggered by Ang II following HIE.

Conclusion

Ang II increased neuronal apoptosis through the AT1R/GSK-3β/mTOR signaling pathway after experimental HIE both in vitro and in vivo, and Ang II may serve as a novel therapeutic target to ameliorate brain injury after HIE.

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.

Dietary Thiols: A Potential Supporting Strategy against Oxidative Stress in Heart Failure and Muscular Damage during Sports Activity

Moderate exercise combined with proper nutrition are considered protective factors against cardiovascular disease and musculoskeletal disorders. However, physical activity is known not only to have positive effects. In fact, the achievement of a good performance requires a very high oxygen consumption, which leads to the formation of oxygen free radicals, responsible for premature cell aging and diseases such as heart failure and muscle injury. In this scenario, a primary role is played by antioxidants, in particular by natural antioxidants that can be taken through the diet. Natural antioxidants are molecules capable of counteracting oxygen free radicals without causing cellular cytotoxicity. In recent years, therefore, research has conducted numerous studies on the identification of natural micronutrients, in order to prevent or mitigate oxidative stress induced by physical activity by helping to support conventional drug therapies against heart failure and muscle damage. The aim of this review is to have an overview of how controlled physical activity and a diet rich in antioxidants can represent a "natural cure" to prevent imbalances caused by free oxygen radicals in diseases such as heart failure and muscle damage. In particular, we will focus on sulfur-containing compounds that have the ability to protect the body from oxidative stress. We will mainly focus on six natural antioxidants: glutathione, taurine, lipoic acid, sulforaphane, garlic and methylsulfonylmethane.

NRF2 in Cardiovascular Diseases: a Ray of Hope!

Heart failure is a worldwide pandemic influencing 26 million individuals worldwide and is expanding. Imbalanced redox homeostasis in cardiac cells alters the structure and function of the cells, which leads to contractile dysfunction, myocardial hypertrophy, and fibrosis in chronic heart failure. Various targets and agents acting on these such as siRNA, miRNA, interleukin-1, opioids, vasodilators, and SGLT2 inhibitors are being evaluated for heart failure, and nuclear factor erythroid 2-related factor 2 (NRF2) is one of them. NRF2 is a master transcription factor which is expressed in most of the tissues and exhibits a major role in amplification of the antioxidant pathways associated with the enzymes present in myocardium. Increased ROS generation and PI3K-Akt signaling can activate the receptor NRF2. Various in vitro and in vivo and few clinical studies suggested NRF2 may possess a potential for targeting oxidative stress-induced cardiovascular diseases including heart failures. All these studies collectively propose that upregulation of NRF2 will attenuate the increase in hemodynamic stress and provide beneficial role in cardiovascular diseases. The current review shall familiarize readers about the regulations and functions of NRF2. We have also discussed the current evidences suggesting beneficial role of NRF2 activators in heart failure. Graphical abstract.

Oxidative stress and diabetic retinopathy: Molecular mechanisms, pathogenetic role and therapeutic implications

Oxidative stress, a cytopathic outcome of excessive generation of ROS and the repression of antioxidant defense system for ROS elimination, is involved in the pathogenesis of multiple diseases, including diabetes and its complications. Retinopathy, a microvascular complication of diabetes, is the primary cause of acquired blindness in diabetic patients. Oxidative stress has been verified as one critical contributor to the pathogenesis of diabetic retinopathy. Oxidative stress can both contribute to and result from the metabolic abnormalities induced by hyperglycemia, mainly including the increased flux of the polyol pathway and hexosamine pathway, the hyper-activation of protein kinase C (PKC) isoforms, and the accumulation of advanced glycation end products (AGEs). Moreover, the repression of the antioxidant defense system by hyperglycemia-mediated epigenetic modification also leads to the imbalance between the scavenging and production of ROS. Excessive accumulation of ROS induces mitochondrial damage, cellular apoptosis, inflammation, lipid peroxidation, and structural and functional alterations in retina. Therefore, it is important to understand and elucidate the oxidative stress-related mechanisms underlying the progress of diabetic retinopathy. In addition, the abnormalities correlated with oxidative stress provide multiple potential therapeutic targets to develop safe and effective treatments for diabetic retinopathy. Here, we also summarized the main antioxidant therapeutic strategies to control this disease.

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Oxidative stress can both contribute to and result from hyperglycemia-induced metabolic abnormalities in retina.

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Genes important in regulation of ROS are epigenetically modified, increasing ROS accumulation in retina.

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Oxidative stress is closely associated with the pathological changes in the progress of diabetic retinopathy.

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Antioxidants ameliorate retinopathy through targeting multiple steps of oxidative stress.

Sulforaphane alleviates ethanol-mediated central inhibition and reverses chronic stress-induced aggravation of acute alcoholism via targeting Nrf2-regulated catalase expression

Acute ethanol intoxication by excessive drinking is an important cause of alcohol-induced death. Stress exposure has been identified as one risk factor for alcohol abuse. Previous reports indicated that stressors may augment inhibitory effects of alcohol, but the underlying mechanism remains unknown. Here, we reported that chronic unpredictable stress increased the sensitivity to the acute ethanol intoxication in mice via impairing nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-catalase signaling. Nrf2 activity regulates the expression of catalase, a key antioxidant enzyme that mediates ethanol oxidation in the brain. Pharmacological blockade of catalase or Nrf2 activity significantly aggravated acute ethanol intoxication. Sulforaphane, a cruciferous vegetable-derived activator of Nrf2, significantly attenuated acute ethanol intoxication. Furthermore, the stress-induced aggravation of acute alcoholism was rapidly reversed by sulforaphane. Our findings suggest that Nrf2 may function as a novel drug target for the prevention of acute alcoholism, especially in psychiatric patients, by controlling catalase-mediated ethanol oxidation.

Astragaloside IV-induced Nrf2 nuclear translocation ameliorates lead-related cognitive impairments in mice

Recently, oxidative stress is a common denominator in the pathogenesis of metal-induced neurotoxicity. Thus, antioxidant therapy is considered as a promising strategy for treating lead-related cognitive impairment. Here, we tested the hypothesis that astragaloside IV (AS-IV) ameliorates lead-associated cognitive deficits through Nrf2-dependent antioxidant mechanisms. Male Nrf2-KO and WT mice received drinking water with 2000 ppm lead and/or AS-IV by gavage for 8 weeks starting at 4 weeks of age. Morris water maze test and biochemical assays were employed to study cognition-enhancing and antioxidant effects of AS-IV. The signaling pathways involved were analyzed using RT-PCR and western blot technology. Significantly, AS-IV attenuated Morris water maze-based cognitive impairment in lead-intoxicated mice. Importantly, cognition-enhancing effect of AS-IV was lost in Nrf2-KO mice. In parallel, AS-IV suppressed lead acetate (PbAc)-induced oxidative stress, as measured by MDA. Mechanistically, AS-IV can up-regulate the expressions of the GCLc and HO-1 at the level of transcription and translation, but not SOD, TrxR activity, GCLm, Trx1, and NQO1 expression. Interestingly, AS-IV induced accumulation of Nrf2 in the nucleus, whereas Nrf2 mRNA levels were unchanged. Furthermore, AS-IV treatment resulted in elevated levels of phosphorylated Akt (active form) and phosphorylated GSK-3β (inactive forms) but decreased level of phosphorylated Fyn. Collectively, our findings indicate that AS-IV may target Nrf2 to attenuate lead-triggered oxidative stress and subsequent cognitive impairments, suggesting that AS-IV is a potential candidate for the treatment of lead-associated cognitive diseases.

Mechanisms of diabetic cardiomyopathy and potential therapeutic strategies: preclinical and clinical evidence

The pathogenesis and clinical features of diabetic cardiomyopathy have been well-studied in the past decade, but effective approaches to prevent and treat this disease are limited. Diabetic cardiomyopathy occurs as a result of the dysregulated glucose and lipid metabolism associated with diabetes mellitus, which leads to increased oxidative stress and the activation of multiple inflammatory pathways that mediate cellular and extracellular injury, pathological cardiac remodelling, and diastolic and systolic dysfunction. Preclinical studies in animal models of diabetes have identified multiple intracellular pathways involved in the pathogenesis of diabetic cardiomyopathy and potential cardioprotective strategies to prevent and treat the disease, including antifibrotic agents, anti-inflammatory agents and antioxidants. Some of these interventions have been tested in clinical trials and have shown favourable initial results. In this Review, we discuss the mechanisms underlying the development of diabetic cardiomyopathy and heart failure in type 1 and type 2 diabetes mellitus, and we summarize the evidence from preclinical and clinical studies that might provide guidance for the development of targeted strategies. We also highlight some of the novel pharmacological therapeutic strategies for the treatment and prevention of diabetic cardiomyopathy.

Role of Nrf2 and Its Activators in Cardiocerebral Vascular Disease

Cardiocerebral vascular disease (CCVD) is a common disease with high morbidity, disability, and mortality. Oxidative stress (OS) is closely related to the progression of CCVD. Abnormal redox regulation leads to OS and overproduction of reactive oxygen species (ROS), which can cause biomolecular and cellular damage. The Nrf2/antioxidant response element (ARE) signaling pathway is one of the most important defense systems against exogenous and endogenous OS injury, and Nrf2 is regarded as a vital pharmacological target. The complexity of the CCVD pathological process and the current difficulties in conducting clinical trials have hindered the development of therapeutic drugs. Furthermore, little is known about the role of the Nrf2/ARE signaling pathway in CCVD. Clarifying the role of the Nrf2/ARE signaling pathway in CCVD can provide new ideas for drug design. This review details the recent advancements in the regulation of the Nrf2/ARE system and its role and activators in common CCVD development.

Exploring the beneficial role of telmisartan in sepsis-induced myocardial injury through inhibition of high-mobility group box 1 and glycogen synthase kinase-3β/nuclear factor-κB pathway

In the present experimental study, cecal ligation and puncture significantly increased the myocardial injury assessed in terms of excess release of creative kinase-MB (CK-MB), cardiac troponin I (cTnI), interleukin (IL)-6 and decrease of IL-10 in the blood following 12 h of laparotomy procedure as compared to normal control. Also, a significant increase in protein expression levels of high-mobility group box 1 (HMGB1) and decreased phosphorylation of glycogen synthase kinase-3β (GSK-3β) was observed in the myocardial tissue as compared to normal control. A single independent administration of telmisartan (2 and 4 mg/kg) and AR-A014418 (1 and 2 mg/kg) substantially reduced sepsis-induced myocardial injury in terms of decrease levels of CK-MB, cTnI and IL-6, HMGB1, GSK-3β and increase in IL-10 and p-GSK-3β in the blood in sepsis- subjected rats. The effects of telmisartan at dose 4 mg/kg and AR-A014418 at a dose of 2 mg/kg were significantly higher than the telmisartan at a dose of 2 mg/kg and AR-A014418 1 mg/kg respectively. Further, no significant effects on different parameters were observed in the sham control group in comparison to normal. Therefore it is plausible to suggest that sepsis may increase the levels of angiotensin II to trigger GSK-3β-dependent signaling to activate the HMGB1/receptors for advanced glycation end products, which may promote inflammation and myocardial injury in sepsis-subjected rats.

Rg1 protects H9C2 cells from high glucose-/palmitate-induced injury via activation of AKT/GSK-3β/Nrf2 pathway

Our previous studies have assessed ginsenoside Rg1 (Rg1)‐mediated protection in a type 1 diabetes rat model. To uncover the mechanism through which Rg1 protects against cardiac injury induced by diabetes, we mimicked diabetic conditions by culturing H9C2 cells in high glucose/palmitate. Rg1 had no toxic effect, and it alleviated the high glucose/palmitate damage in a dose‐dependent manner, as indicated by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide assay and lactate dehydrogenase release to the culture medium. Rg1 prevented high glucose/palmitate‐induced cell apoptosis, assessed using cleaved caspase‐3 and terminal deoxynucleotidyl transferase dUTP nick end labelling staining. Rg1 also reduced high glucose‐/palmitate‐induced reactive oxygen species formation and increased intracellular antioxidant enzyme activity. We found that Rg1 activates protein kinase B (AKT)/glycogen synthase kinase‐3 (GSK‐3β) pathway and antioxidant nuclear factor erythroid 2‐related factor 2 (Nrf2) pathway, indicated by increased phosphorylation of AKT and GSK‐3β, and nuclear translocation of Nrf2. We used phosphatidylinositol‐3‐kinase inhibitor Ly294002 to block the activation of the AKT/GSK‐3β pathway and found that it partially reversed the protection by Rg1 and decreased Nrf2 pathway activation. The results suggest that Rg1 exerts a protective effect against high glucose and palmitate damage that is partially AKT/GSK‐3β/Nrf2‐mediated. Further studies are required to validate these findings using primary cardiomyocytes and animal models of diabetes.

Sulforaphane protects against skeletal muscle dysfunction in spontaneous type 2 diabetic db/db mice

AIMS

Skeletal muscle diseases have become to be the most common complication in patients with type 2 diabetic mellitus (T2DM). However, the effective therapies against skeletal muscle diseases are not yet available. Sulforaphane (SFN) is an organic isothiocyanate found in cruciferous plants. Our aim was to explore whether SFN could attenuate the skeletal muscle diseases in spontaneous type 2 diabetic db/db mice.

MATERIALS AND METHODS

The db/m and littermate db/db mice were treated with SFN or dimethyl sulfoxide. The grip strength of mice was measured by a grasping forcing machine. The electron transmission microscopy was used to perform the skeletal muscle. The western blot was used to detect the nuclear factor E2-related factor 2/heme oxygenase 1 (Nrf2/HO-1) signal pathway related proteins, and inflammatory and apoptotic associated proteins. The mRNA levels of anti-inflammatory and anti-oxidative relative genes were detected by RT-QPCR.

KEY FINDINGS

We found that SFN could significantly increase the grip strength of the db/db mice. The lean mass and gastrocnemius mass were increased in the db/db mice after administration with SFN. Additionally, the db/db mice restored the skeletal muscle fiber organization after SFN treatment. Mechanistically, SFN could activate the Nrf2/HO-1 signal pathway, and downregulate the expression of inflammatory and apoptotic associated proteins. Furthermore, SFN could also regulate the mRNA levels of anti-inflammatory and anti-oxidative related genes.

SIGNIFICANCE

Our results demonstrated that SFN can protect against skeletal muscle diseases in db/db type 2 diabetic mice and provide a potential drug to prevent skeletal muscle dysfunction in T2DM patients.

Sulforaphane prevents chromium-induced lung injury in rats via activation of the Akt/GSK-3β/Fyn pathway

Chromium (Cr) is an internationally recognized carcinogenic hazard that causes serious pulmonary toxicity. However, Cr-induced pulmonary toxicity lacks effective treatment to date. Sulforaphane (SFN), a well-known organosulfur compound, has gained increasing attention because of its unique biological function. This study investigates if SFN could decrease K₂Cr₂O₇-induced pulmonary toxicity and a potential mechanism involved using a rat 35-day Cr-induced pulmonary toxicity model and the mouse alveolar type II epithelial cell line (MLE-12). The results showed that SFN prevented Cr-induced oxidative stress, histopathological lesions, inflammation, apoptosis, and changes in protein kinase B (Akt) and glycogen synthase kinase 3 beta (GSK-3β) levels in vivo and in vitro. However, SFN can not play the protective effect against K₂Cr₂O₇-induced cell injury after treating by an Akt-specific inhibitor (MK-2206 2HCl) in MLE-12 cells. Furthermore, SFN increased the expression of nuclear factor-E2-related factor-2 (Nrf2) phase II detoxification enzymes. Collectively, this study demonstrates that SFN prevents K₂Cr₂O₇-induced lung toxicity in rats through enhancing Nrf2-mediated exogenous antioxidant defenses via activation of the Akt/GSK-3β/Fyn signaling pathway. SFN may be a novel natural substance to cure Cr-induced lung toxicity.

Sulforaphane prevents right ventricular injury and reduces pulmonary vascular remodeling in pulmonary arterial hypertension

Right ventricular (RV) dysfunction is the main determinant of mortality in patients with pulmonary arterial hypertension (PAH) and while inflammation is pathogenic in PAH, there is limited information on the role of RV inflammation in PAH. Sulforaphane (SFN), a potent Nrf2 activator, has significant anti-inflammatory effects and facilitates cardiac protection in preclinical diabetic models. Therefore, we hypothesized that SFN might play a comparable role in reducing RV and pulmonary inflammation and injury in a murine PAH model. We induced PAH using SU5416 and 10% hypoxia (SuHx) for 4 wk in male mice randomized to SFN at a daily dose of 0.5 mg/kg 5 days per week for 4 wk or to vehicle control. Transthoracic echocardiography was performed to characterize chamber-specific ventricular function during PAH induction. At 4 wk, we measured RV pressure and relevant measures of histology and protein and gene expression. SuHx induced progressive RV, but not LV, diastolic and systolic dysfunction, and RV and pulmonary remodeling, fibrosis, and inflammation. SFN prevented SuHx-induced RV dysfunction and remodeling, reduced RV inflammation and fibrosis, upregulated Nrf2 expression and its downstream gene NQO1, and reduced the inflammatory mediator leucine-rich repeat and pyrin domain-containing 3 (NLRP3). SFN also reduced SuHx-induced pulmonary vascular remodeling, inflammation, and fibrosis. SFN alone had no effect on the heart or lungs. Thus, SuHx-induced RV and pulmonary dysfunction, inflammation, and fibrosis can be attenuated or prevented by SFN, supporting the rationale for further studies to investigate SFN and the role of Nrf2 and NLRP3 pathways in preclinical and clinical PAH studies.NEW & NOTEWORTHY Pulmonary arterial hypertension (PAH) in this murine model (SU5416 + hypoxia) is associated with early changes in right ventricular (RV) diastolic and systolic function. RV and lung injury in the SU5416 + hypoxia model are associated with markers for fibrosis, inflammation, and oxidative stress. Sulforaphane (SFN) alone for 4 wk has no effect on the murine heart or lungs. Sulforaphane (SFN) attenuates or prevents the RV and lung injury in the SUF5416 + hypoxia model of PAH, suggesting that Nrf2 may be a candidate target for strategies to prevent or reverse PAH.