Palmitate promotes autophagy and apoptosis through ROS-dependent JNK and p38 MAPK

Crosstalk among Reactive Oxygen Species, Autophagy and Metabolism in Myocardial Ischemia and Reperfusion Stages

Myocardial ischemia is the most common cardiovascular disease. Reperfusion, an important myocardial ischemia tool, causes unexpected and irreversible damage to cardiomyocytes, resulting in myocardial ischemia/reperfusion (MI/R) injury. Upon stress, especially oxidative stress induced by reactive oxygen species (ROS), autophagy, which degrades the intracellular energy storage to produce metabolites that are recycled into metabolic pathways to buffer metabolic stress, is initiated during myocardial ischemia and MI/R injury. Excellent cardioprotective effects of autophagy regulators against MI and MI/R have been reported. Reversing disordered cardiac metabolism induced by ROS also exhibits cardioprotective action in patients with myocardial ischemia. Herein, we review current knowledge on the crosstalk between ROS, cardiac autophagy, and metabolism in myocardial ischemia and MI/R. Finally, we discuss the possible regulators of autophagy and metabolism that can be exploited to harness the therapeutic potential of cardiac metabolism and autophagy in the diagnosis and treatment of myocardial ischemia and MI/R.

A review of chemotherapeutic drugs-induced arrhythmia and potential intervention with traditional Chinese medicines

Significant advances in chemotherapy drugs have reduced mortality in patients with malignant tumors. However, chemotherapy-related cardiotoxicity increases the morbidity and mortality of patients, and has become the second leading cause of death after tumor recurrence, which has received more and more attention in recent years. Arrhythmia is one of the common types of chemotherapy-induced cardiotoxicity, and has become a new risk related to chemotherapy treatment, which seriously affects the therapeutic outcome in patients. Traditional Chinese medicine has experienced thousands of years of clinical practice in China, and has accumulated a wealth of medical theories and treatment formulas, which has unique advantages in the prevention and treatment of malignant diseases. Traditional Chinese medicine may reduce the arrhythmic toxicity caused by chemotherapy without affecting the anti-cancer effect. This paper mainly discussed the types and pathogenesis of secondary chemotherapeutic drug-induced arrhythmia (CDIA), and summarized the studies on Chinese medicine compounds, Chinese medicine Combination Formula and Chinese medicine injection that may be beneficial in intervention with secondary CDIA including atrial fibrillation, ventricular arrhythmia and sinus bradycardia, in order to provide reference for clinical prevention and treatment of chemotherapy-induced arrhythmias.

Analysis of abnormal expression of signaling pathways in PQ-induced acute lung injury in SD rats based on RNA-seq technology

Background: Paraquat (PQ) plays an important role in agricultural production due to its highly effective herbicidal effect. However, it has led to multiple organ failure in those who have been poisoned, with damage most notable in the lungs and ultimately leading to death. Because of little research has been performed at the genetic level, and therefore, the specific genetic changes caused by PQ exposure are unclear.Methods: Paraquat poisoning model was constructed in Sprague Dawley (SD) rats, and SD rats were randomly divided into Control group, paraquat (PQ) poisoning group and Anthrahydroquinone-2,6-disulfonate (AH2QDS) treatment group. Then, the data was screened and quality controlled, compared with reference genes, optimized gene structure, enriched at the gene expression level, and finally, signal pathways with significantly different gene enrichment were screened.Results: This review reports on lung tissues from paraquat-intoxicated Sprague Dawley (SD) rats that were subjected to RNA-seq, the differentially expressed genes were mainly enriched in PI3K-AKT, cGMP-PKG, MAPK, Focal adhesion and other signaling pathways.Conclusion: The signaling pathways enriched with these differentially expressed genes are summarized, and the important mechanisms mediated through these pathways in acute lung injury during paraquat poisoning are outlined to identify important targets for AH2QDS treatment of acute lung injury due to paraquat exposure, information that will be used to support a subsequent in-depth study on the mechanism of PQ action.

Yohimbine ameliorates liver inflammation and fibrosis by regulating oxidative stress and Wnt/β-catenin pathway

BACKGROUND AND PURPOSE

Chronic liver injury, caused by various aetiologies, causes recurrent tissue damage, culminating in decreased liver regenerative ability and resulting in fibrosis followed by cirrhosis. In this study, the anti-fibrotic activity of Yohimbine hydrochloride (YHC) was investigated using various in vitro models and in vivo models.

METHODS

To assess the anti-inflammatory, antioxidant, and anti-fibrotic effects of YHC, lipopolysaccharide or TGF-β induced differentiation or lipid-induced oxidative-stress models were employed using HLECs, HSC-LX2, and HepG2 cells. Further, thioacetamide (TAA) induced hepatic inflammation/fibrosis models were utilized to validate the YHC's anti-fibrotic activity in rats.

RESULTS

Inflammation/differentiation experiments in HLECs and HSC-LX2 revealed that YHC treatment significantly (p < 0.001) mitigated the lipopolysaccharide or TGF-β induced upregulation of inflammatory and fibrotic markers expression respectively. In addition, YHC dose-dependently reduced the TGF-β induced migration and palmitic acid-induced oxidative stress in HepG2 cells. Further, TAA administration (5 weeks) in vivo rat model showed increased inflammatory marker levels/expression, oxidative stress, and pathological abnormalities. Additionally, TAA administration (9 weeks) elevated the fibrotic marker expression, collagen deposition in liver tissues, and shortened longevity in rats. Treatment with YHC dose-dependently mitigated the TAA-induced abnormalities in both inflammation and fibrosis models and improved the survival of the rats. Further mechanistic approaches revealed that TAA administration elevated the JNK, Wnt components and β-catenin expression in hepatic stellate cells and animal tissues. Further treatment with YHC significantly modulated the JNK/Wnt/β-catenin signaling. Moreover, the β-catenin nuclear translocation results showed that β-catenin levels were significantly elevated in the nuclear fraction of TAA control samples and reduced in YHC-treated samples.

CONCLUSION

Yohimbine treatment significantly improved inflammation and fibrosis by inhibiting differentiation, oxidative stress, and collagen deposition by partly modulating the JNK/Wnt/β-catenin pathway. These results might serve as a foundation for proposing yohimbine as a potential lead compound for liver fibrosis.

TXNIP inhibition in the treatment of type 2 diabetes mellitus: design, synthesis, and biological evaluation of quinazoline derivatives

Thioredoxin interacting protein (TXNIP) is a potential drug target for type 2 diabetes mellitus (T2DM) treatment. A series of quinazoline derivatives were designed, synthesised, and evaluated to inhibit TXNIP expression and protect from palmitate (PA)-induced β cell injury. In vitro cell viability assay showed that compounds D-2 and C-1 could effectively protect β cell from PA-induced apoptosis, and subsequent results showed that these two compounds decreased TXNIP expression by accelerating its protein degradation. Mechanistically, compounds D-2 and C-1 reduced intracellular reactive oxygen species (ROS) production and modulated TXNIP-NLRP3 inflammasome signalling, and thus alleviating oxidative stress injury and inflammatory response under PA insult. Besides, these two compounds were predicted to possess better drug-likeness properties using SwissADME. The present study showed that compounds D-2 and C-1, especially compound D-2, were potent pancreatic β cell protective agents to inhibit TXNIP expression and might serve as promising lead candidates for the treatment of T2DM.

Shengmai injection inhibits palmitic acid-induced myocardial cell inflammatory death via regulating NLRP3 inflammasome activation

Objective

To determine the protective effect of Shengmai injection (SMI) on myocardial injury in diabetic rats and its mechanism based on NLRP3/Caspase1 signaling pathway.

Materials and methods

Rat H9c2 cardiomyocytes were cultured in vitro, and the cell survival rate of different concentrations of palmitate acid (PA) and different concentrations of SMI were detected by CCK-8. The myocardial injury cell model was induced with PA, treated with SMI, and combined with NLRP3 specific inhibitor (MCC950) to interfere with the high-fat-induced rat H9c2 myocardial cell injury model. The cell changes were observed by Hoechst/PI staining and the expression levels of MDA, SOD, and ROS in each group were detected. The protein and gene changes of the NLRP3/Caspase-1 signaling pathway were detected by Western blot and RT-qPCR, respectively.

Results

200 μmol/L of PA were selected to induce the myocardial injury cell model and 25 μL/mL of SMI was selected for intervention concentration. SMI could significantly reduce MDA expression, increase SOD level, and decrease ROS production. SMI could decrease the gene expression levels of NLRP3, ASC, Caspase-1, and GSDMD, and the protein expressions of NLRP3, ASC, Cleaved Caspase-1, GSDMD, and GSDMD-N.

Conclusion

SMI can inhibit the high-fat-induced activation of the NLRP3/Caspase-1 signaling pathway, intervene in cardiomyocyte pyroptosis, and prevent diabetic cardiomyopathy.

URAT1 is expressed in cardiomyocytes and dotinurad attenuates the development of diet-induced metabolic heart disease

We recently reported that the selective inhibition of urate transporter-1 (URAT1), which is primarily expressed in the kidneys, ameliorates insulin resistance by attenuating hepatic steatosis and improving brown adipose tissue function in diet-induced obesity. In this study, we evaluated the effects of dotinurad, a URAT1-selective inhibitor, on the hearts of high-fat diet (HFD)-fed obese mice for 16-20 weeks and on neonatal rat cardiomyocytes (NRCMs) exposed to palmitic acid. Outside the kidneys, URAT1 was also expressed in cardiomyocytes and indeed worked as a uric acid transporter. Dotinurad substantially attenuated HFD-induced cardiac fibrosis, inflammatory responses, and cardiac dysfunction. Intriguingly, among various factors related to the pathophysiology of diet-induced obesity, palmitic acid significantly increased URAT1 expression in NRCMs and subsequently induced apoptosis, oxidative stress, and inflammatory responses via MAPK pathway, all of which were reduced by dotinurad. These results indicate that URAT1 is a potential therapeutic target for metabolic heart disease.

Cytoprotective Effect of Bambusae caulis in Liquamen by Blocking Oxidative Stress in Hepatocytes

Bambusae caulis in Liquamen (BCL), which is extracted from heat-treated fresh bamboo stems, is a traditional herbal medicine widely used in Eastern countries. Recently, it has been reported to have anti-inflammatory and whitening effects. However, the protective effect of BCL on hepatocytes has not yet been elucidated. The present study aimed to determine whether BCL prevents oxidative stress induced by tert-butyl hydroperoxide (t-BHP) and exerts cytoprotective effects on hepatocytes. High-performance liquid chromatography and liquid chromatography with tandem mass spectroscopy were performed to analyze the type of polyphenols present in BCL. The activities of antioxidant enzymes and hepatocyte viability were assessed. The benzoic acid content was the highest among polyphenols present in BCL. Benzoic acid acts as a scavenger of free radicals, including reactive oxygen species. BCL increased the expression of antioxidant enzymes (glutamate-cysteine ligase and NADPH quinone dehydrogenase (1)) by activating nuclear factor erythroid 2-related factor 2 and reduced tBHP-induced cell death by inhibiting oxidative stress. BCL inhibited tBHP-induced phosphorylation of p38 and c-Jun N-terminal kinase but not that of extracellular signal-regulated kinase. In conclusion, BCL is a promising therapeutic candidate for treating oxidative-stress-induced hepatocyte damage.

Distinct Signaling Pathways for Autophagy-Driven Cell Death and Survival in Adult Hippocampal Neural Stem Cells

Autophagy is a cellular catabolic process that degrades and recycles cellular materials. Autophagy is considered to be beneficial to the cell and organism by preventing the accumulation of toxic protein aggregates, removing damaged organelles, and providing bioenergetic substrates that are necessary for survival. However, autophagy can also cause cell death depending on cellular contexts. Yet, little is known about the signaling pathways that differentially regulate the opposite outcomes of autophagy. We have previously reported that insulin withdrawal (IW) or corticosterone (CORT) induces autophagic cell death (ACD) in adult hippocampal neural stem (HCN) cells. On the other hand, metabolic stresses caused by 2-deoxy-D-glucose (2DG) and glucose-low (GL) induce autophagy without death in HCN cells. Rather, we found that 2DG-induced autophagy was cytoprotective. By comparing IW and CORT conditions with 2DG treatment, we revealed that ERK and JNK are involved with 2DG-induced protective autophagy, whereas GSK-3β regulates death-inducing autophagy. These data suggest that cell death and survival-promoting autophagy undergo differential regulation with distinct signaling pathways in HCN cells.

Role of autophagy in simulated ischemic-reperfused left atrial myocardium

BACKGROUND AND AIM

Autophagy has recently emerged as a potential and promising therapeutic approach to maintain cardiac cellular homeostasis. The aim of the present study was to investigate the role of autophagy in the ischemic-reperfused atrial myocardium.

METHODS

Isolated rat left atria subjected to simulated ischemia-reperfusion were used. The bathing medium contained either 10 mM d-glucose or 10 mM d-glucose and 1.2 mM palmitate. 3-methyladenine (3-MA) was used as pharmacological autophagy inhibitor.

RESULTS

LC3-II/LC3-I ratio, an indicator of autophagosome formation, was significantly enhanced during reperfusion, this increase being slowed by the exposure to high palmitate concentration and prevented by 3-MA. Beclin-1 was significantly increased during reperfusion period in both metabolic conditions, and pharmacological inhibition of AMPK partially prevented LC3-II/LC3-I ratio increase. Autophagy inhibition significantly increased mitochondrial damage and impaired mitochondrial ATP synthesis rate at reperfusion. Tissue ATP content recovery and contractile reserve were also reduced during this period, these effects being more pronounced either in 3-MA treated atria and ischemic-reperfused atria incubated with palmitate. Moreover, severe tachyarrhythmias were observed in the presence of 3-MA, in both metabolic conditions. This phenomenon was partially prevented by mitochondrial inner membrane ion channels blocker, PK11195.

CONCLUSION

Present study provides new insights into the role of autophagy in ischemic-reperfused atrial myocardium. The observation of greater deterioration in mitochondrial structure and function when this process was inhibited, suggests an association between autophagy and the structural and functional preservation of mitochondria. Exogenous metabolic substrates, to which the myocardium is exposed during ischemia-reperfusion, might not affect this process.

Involvement of p38 MAPK in Leydig cell aging and age-related decline in testosterone

INTRODUCTION

Age-related decline in testosterone is associated with Leydig cell aging with impaired testosterone synthesis in aging. Obesity accelerates the age-related decline in testosterone. However, the mechanisms underlying the Leydig cell aging and the effects of obesity on Leydig cell aging remain unclear.

METHOD

Natural aging mice and diet-induced obese mice were used to assess the process of testicular Leydig cell senescence with age or obesity. Bioinformatic analysis of the young and aged human testes was used to explore key genes related Leydig cell aging. Leydig cell-specific p38 MAPK knockout (p38LCKO) mice were used to further analyze the roles of p38 MAPK in Leydig cell aging. The levels of testosterone and steroidogenic enzymes, activity of p38 MAPK, aging status of Leydig cells, and oxidative stress and inflammation of testes or Leydig cells were detected by ELISA, immunoblotting, immunofluorescence, and senescence-associated β-galactosidase (SA-β-Gal) staining analysis, respectively.

RESULT

The serum testosterone level was significantly reduced in aged mice compared with young mice. In the testis of aged mice, the reduced mRNA and protein levels of LHCGR, SRB1, StAR, CYP11A1, and CYP17A1 and the elevated oxidative stress and inflammation were observed. KEGG analysis showed that MAPK pathway was changed in aged Leydig cells, and immunoblotting displayed that p38 MAPK was activated in aged Leydig cells. The intensity of SA-β-Gal staining on Leydig cells and the number of p21-postive Leydig cells in aged mice were more than those of young mice. Similar to aged mice, the testosterone-related indexes decreased, and the age-related indexes increased in the testicular Leydig cells of high fat diet (HFD) mice. Aged p38LCKO mice had higher levels of testosterone and steroidogenic enzymes than those of age-matched wild-type (WT) littermates, with reduced the intensity of SA-β-Gal staining and the expression of p21 protein.

CONCLUSION

Our study suggested that obesity was an important risk factor for Leydig cell aging. p38 MAPK was involved in Leydig cell aging induced by age and obesity. The inhibition of p38 MAPK could delay Leydig cell aging and alleviate decline in testosterone.

Gallic acid suppresses the progression of triple-negative breast cancer HCC1806 cells via modulating PI3K/AKT/EGFR and MAPK signaling pathways

Triple-negative breast cancer (TNBC) is a severe threat to women’s health because of its aggressive nature, early age of onset, and high recurrence rate. Therefore, in this study, we aimed to evaluate the anti-tumor effects of Gallic acid (GA) on the TNBC HCC1806 cells in vitro. The cell proliferation was detected by MTT and plate clone formation assays, cell apoptosis, cell cycle, and mitochondrial membrane potential (MMP) were analyzed by flow cytometry and Hoechst 33258 staining assays, and the intracellular reactive oxygen species (ROS) accumulation were also investigated. Real-Time PCR and western blot were examined to explore the mechanism of action. The results indicated that GA suppressed HCC1806 cells proliferation and promoted HCC1806 cells apoptosis. Meanwhile, GA treatment changed the morphology of the HCC1806 cells. In addition, GA blocked the HCC1806 cells cycle in the S phase, and it induced cells apoptosis accompanied by ROS accumulation and MMP depolarization. Real-Time PCR results suggested that GA increased Bax, Caspase-3, Caspase-9, P53, JINK and P38 mRNA expression, and decreased Bcl-2, PI3K, AKT and EGFR mRNA expression. Western blotting results suggested that GA increased Bax, cleaved-Caspase-3, cleaved-Caspase-9, P53, P-ERK1/2, P-JNK, P-P38 proteins expression, and decreased Bcl-2, P-PI3K, P-AKT, P-EGFR proteins expression. Furthermore, molecular docking suggested that GA has the high affinity for PI3K, AKT, EGFR, ERK1/2, JNK, and P38. In conclusion, GA could suppress HCC1806 cells proliferation and promote HCC1806 cells apoptosis through the mitochondrial apoptosis pathway and induces ROS generation which further inhibits PI3K/AKT/EGFR and activates MAPK signaling pathways. Our study will provide some new references for using GA in the treatment of TNBC.

Redox balance and autophagy regulation in cancer progression and their therapeutic perspective

Cellular ROS production participates in various cellular functions but its accumulation decides the cell fate. Malignant cells have higher levels of ROS and active antioxidant machinery, a characteristic hallmark of cancer with an outcome of activation of stress-induced pathways like autophagy. Autophagy is an intracellular catabolic process that produces alternative raw materials to meet the energy demand of cells and is influenced by the cellular redox state thus playing a definite role in cancer cell fate. Since damaged mitochondria are the main source of ROS in the cell, however, cancer cells remove them by upregulating the process of mitophagy which is known to play a decisive role in tumorigenesis and tumor progression. Chemotherapy exploits cell machinery which results in the accumulation of toxic levels of ROS in cells resulting in cell death by activating either of the pathways like apoptosis, necrosis, ferroptosis or autophagy in them. So understanding these redox and autophagy regulations offers a promising method to design and develop new cancer therapies that can be very effective and durable for years. This review will give a summary of the current therapeutic molecules targeting redox regulation and autophagy for the treatment of cancer. Further, it will highlight various challenges in developing anticancer agents due to autophagy and ROS regulation in the cell and insights into the development of future therapies.

Polystyrene nanoplastics exacerbated lipopolysaccharide-induced necroptosis and inflammation via the ROS/MAPK pathway in mice spleen

Plastics are novel environmental pollutants with potential threats to the ecosystem. At least 5.25 trillion plastic particles in the environment, of which nanoplastics are <100 nm in diameter. Polystyrene nanoplastics (PS-NPs) exposure damaged the spleen's immune function. Lipopolysaccharide (LPS) induced other toxicants to damage cells and organs, triggering inflammation. However, the mechanism of PS-NPs aggravated LPS-induced spleen injury remains unclear. In this study, the PS-NPs or/and LPS mice exposure model was replicated by intraperitoneal injection of PS-NPs or/and LPS, and PS-NPs or/and LPS were exposed to RAW264.7 cells. The histopathological and ultrastructural changes of the mice spleen were observed by H&E staining and transmission electron microscope. Western Blot, qRT-PCR, and fluorescent probes staining were used to detect reactive oxygen species (ROS), oxidative stress indicators, inflammatory factors, and necroptosis-related indicators in mice spleen and RAW264.7 cells. The results showed that PS-NPs or LPS induced oxidative stress, activated the MAPK pathway, and eventually caused necroptosis and inflammation in mice spleen and RAW264.7 cells. Compared with the single treatment group, the changes in PS-NPs + LPS group were more obvious. Furthermore, ROS inhibitor N-Acetyl-L-cysteine (NAC) significantly inhibited the activation of the mitogen-activated protein kinase (MAPK) signaling pathway caused by co-treatment of PS-NPs and LPS, reducing necroptosis and inflammation. The results demonstrated that PS-NPs promoted LPS-induced spleen necroptosis and inflammation in mice through the ROS/MAPK pathway. This study increases the data on the damage of PS-NPs to the organism and expands the research ideas and clues.

Disturbed Cardiac Metabolism Triggers Atrial Arrhythmogenesis in Diabetes Mellitus: Energy Substrate Alternate as a Potential Therapeutic Intervention

Atrial fibrillation (AF) is the most common type of sustained arrhythmia in diabetes mellitus (DM). Its morbidity and mortality rates are high, and its prevalence will increase as the population ages. Despite expanding knowledge on the pathophysiological mechanisms of AF, current pharmacological interventions remain unsatisfactory; therefore, novel findings on the underlying mechanism are required. A growing body of evidence suggests that an altered energy metabolism is closely related to atrial arrhythmogenesis, and this finding engenders novel insights into the pathogenesis of the pathophysiology of AF. In this review, we provide comprehensive information on the mechanistic insights into the cardiac energy metabolic changes, altered substrate oxidation rates, and mitochondrial dysfunctions involved in atrial arrhythmogenesis, and suggest a promising advanced new therapeutic approach to treat patients with AF.

Polyacylated Anthocyanins Derived from Red Radishes Protect Vascular Endothelial Cells Against Palmitic Acid-Induced Apoptosis via the p38 MAPK Pathway

Palmitic acid (PA), a widely consumed saturated fat, is known to induce the apoptosis of vascular endothelial cells. This study examined the protective effect of anthocyanin from red radish (ARR), which has been shown to protect the cardiovascular system and is rich in polyacylated pelargonidin (P) glycosides, on PA-treated SV 40 transfected aortic rat endothelial cells (SVAREC). In all, 22 distinct anthocyanins were identified in the ARR via ultra-high-performance liquid chromatography-triple quadrupole mass spectrometry, the most abundant of which were pelargonidin-3-(p-coumaroyl)diglucoside-5-glucoside (31.60%), pelargonidin-3-(feruloyl)diglucoside-5-(malonyl)glucoside (22.98%), pelargonidin-3-(p-coumaroyl)diglucoside-5-(malonyl)glucoside (8.02%), and pelargonidin-3-(feruloyl)diglucoside-5-glucoside (6.25%). P displayed the highest serum level (93.72%) in the ARR-treated mice, while polyacylated P glucosides were also absorbed intact. Furthermore, ARR treatment effectively increased cellular activity and reduced the ratio of Bcl-2-associated X protein : B cell lymphoma-2, while simultaneously alleviating the excessive production of reactive oxygen species in PA-treated SVAREC. Transcriptome and further verification analyses confirmed that the ARR-inhibiting PA-induced apoptosis of SVAREC was related to the p38 mitogen-activated protein kinase signaling pathway. Our results are the first to demonstrate that ARR may be a promising phytochemical in the prevention of PA-induced endothelial dysfunction.

Glutamate excitotoxicity: Potential therapeutic target for ischemic stroke

Glutamate-mediated excitotoxicity is an important mechanism leading to post ischemic stroke damage. After acute stroke, the sudden reduction in cerebral blood flow is most initially followed by ion transport protein dysfunction and disruption of ion homeostasis, which in turn leads to impaired glutamate release, reuptake, and excessive N-methyl-D-aspartate receptor (NMDAR) activation, promoting neuronal death. Despite extensive evidence from preclinical studies suggesting that excessive NMDAR stimulation during ischemic stroke is a central step in post-stroke damage, NMDAR blockers have failed to translate into clinical stroke treatment. Current treatment options for stroke are very limited, and there is therefore a great need to develop new targets for neuroprotective therapeutic agents in ischemic stroke to extend the therapeutic time window. In this review, we highlight recent findings on glutamate release, reuptake mechanisms, NMDAR and its downstream cellular signaling pathways in post-ischemic stroke damage, and review the pathological changes in each link to help develop viable new therapeutic targets. We then also summarize potential neuroprotective drugs and therapeutic approaches for these new targets in the treatment of ischemic stroke.

Hua-Tan-Sheng-Jing Decoction Treats Obesity With Oligoasthenozoospermia by Up-Regulating the PI3K-AKT and Down-Regulating the JNK MAPK Signaling Pathways: At the Crossroad of Obesity and Oligoasthenozoospermia

Background: Oligoasthenozoospermia is the leading cause of male infertility, seriously affecting men's health and increasing the societal medical burden. In recent years, obesity-related oligoasthenozoospermia has attracted increased attention from researchers to find a cure. This study aimed to evaluate the efficacy of Hua-Tan-Sheng-Jing decoction (HTSJD) in treating obesity with oligoasthenozoospermia, determine its active ingredients and identify its mechanism of action. Methods: The ingredients of HTSJD were determined by combining the ultra-performance liquid chromatography with mass spectrometry (UPLC-MS/MS) and systems pharmacology approach. The common pathogenesis of obesity and oligoasthenozoospermia and the potential mechanism of HTSJD against obesity with oligoasthenozoospermia were obtained through target fishing, network construction, and enrichment analyses. Further, molecular docking of the key ingredients with the upstream receptors of the key signaling pathways of the potential mechanism was used to predict their affinity. Finally, high-fat-induced obesity with oligoasthenozoospermia rat model was constructed to determine the effects of HTSJD on semen concentration, sperm motility, body weight, and serum lipid metabolism. The key proteins were validated by immunohistochemistry (IHC). Results: A total of 70 effective components and 847 potential targets of HTSJD (H targets) were identified, of which 743 were common targets related to obesity and oligoasthenozoospermia (O-O targets) mainly enriched in the pathways related to inflammation, oxidative stress and hormone regulation. Finally, 143 common targets (H-O-O targets) for HTSJD against obesity with oligoasthenozoospermia were obtained. Combining the hub genes and the results of Gene Ontology (GO) functional and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of H-O-O targets, PI3K-AKT and MAPK signaling pathways were identified as the key pathways. Molecular docking results showed that Diosgenin, Kaempferol, Quercetin, Hederagenin, Isorhamnetin may act on the related pathways by docking EGFR, IGF1R and INSR. The animal-based in vivo experiments confirmed that HTSJD improves the sperm quality of high-fat diet-fed rats by reducing their body weight and blood lipid levels, influencing the PI3K-AKT and MAPK signaling pathways and altering the corresponding protein expressions. Conclusion: HTSJD treats obesity with oligoasthenozoospermia by up-regulating the PI3K-AKT signaling pathway and down-regulating the MAPK signaling pathway, which are at the crossroad of obesity and oligoasthenozoospermia.

Cimifugin Ameliorates Lipotoxicity-Induced Hepatocyte Damage and Steatosis through TLR4/p38 MAPK- and SIRT1-Involved Pathways

Objective. Hepatic metabolic disorder induced by lipotoxicity plays a detrimental role in metabolic fatty liver disease pathogenesis. Cimifugin (Cim), a coumarin derivative extracted from the root of Saposhnikovia divaricata, possesses multiple biological properties against inflammation, allergy, and oxidative stress. However, limited study has addressed the hepatoprotective role of Cim. Here, we investigate the protective effect of Cim against lipotoxicity-induced cytotoxicity and steatosis in hepatocytes and clarify its potential mechanisms. Methods. AML-12, a nontransformed mouse hepatocyte cell line, was employed in this study. The cells were incubated with palmitate or oleate to imitate hepatotoxicity or steatosis model, respectively. Results. Cim significantly reversed palmitate-induced hepatocellular injury in a dose-dependent manner, accompanied by improvements in oxidative stress and mitochondrial damage. Cim pretreatment reversed palmitate-stimulated TLR4/p38 MAPK activation and SIRT1 reduction without affecting JNK, ERK1/2, and AMPK pathways. The hepatoprotective effects of Cim were abolished either through activating TLR4/p38 by their pharmacological agonists or genetical silencing SIRT1 via special siRNA, indicating a mechanistic involvement. Moreover, Cim treatment improved oleate-induced hepatocellular lipid accumulation, which could be blocked by either TLR4 stimulation or SIRT1 knockdown. We observed that SIRT1 was a potential target of TLR4 in palmitate-treated hepatocytes, since TLR4 agonist LPS aggravated, whereas TLR4 antagonist CLI-095 alleviated palmitate-decreased SIRT1 expression. SIRT1 knockdown did not affect palmitate-induced TLR4. In addition, TLR4 activation by LPS significantly abolished Cim-protected SIRT1 reduction induced by palmitate. These results collaboratively indicated that TLR4-regulated SIRT1 pathways was mechanistically involved in the protective effects of Cim against lipotoxicity. Conclusion. In brief, we demonstrate the protective effects of Cim against lipotoxicity-induced cell death and steatosis in hepatocytes. TLR4-regulated p38 MAPK and SIRT1 pathways are involved in Cim-protected hepatic lipotoxicity. Cim is a potential candidate for improving hepatic metabolic disorders mediated by lipotoxicity.

Methylmercury Induces Mitochondria- and Endoplasmic Reticulum Stress-Dependent Pancreatic β-Cell Apoptosis via an Oxidative Stress-Mediated JNK Signaling Pathway

Methylmercury (MeHg), a long-lasting organic pollutant, is known to induce cytotoxic effects in mammalian cells. Epidemiological studies have suggested that environmental exposure to MeHg is linked to the development of diabetes mellitus (DM). The exact molecular mechanism of MeHg-induced pancreatic β-cell cytotoxicity is still unclear. Here, we found that MeHg (1-4 μM) significantly decreased insulin secretion and cell viability in pancreatic β-cell-derived RIN-m5F cells. A concomitant elevation of mitochondrial-dependent apoptotic events was observed, including decreased mitochondrial membrane potential and increased proapoptotic (Bax, Bak, p53)/antiapoptotic (Bcl-2) mRNA ratio, cytochrome c release, annexin V-Cy3 binding, caspase-3 activity, and caspase-3/-7/-9 activation. Exposure of RIN-m5F cells to MeHg (2 μM) also induced protein expression of endoplasmic reticulum (ER) stress-related signaling molecules, including C/EBP homologous protein (CHOP), X-box binding protein (XBP-1), and caspase-12. Pretreatment with 4-phenylbutyric acid (4-PBA; an ER stress inhibitor) and specific siRNAs for CHOP and XBP-1 significantly inhibited their expression and caspase-3/-12 activation in MeHg-exposed RIN-mF cells. MeHg could also evoke c-Jun N-terminal kinase (JNK) activation and reactive oxygen species (ROS) generation. Antioxidant N-acetylcysteine (NAC; 1mM) or 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox; 100 μM) markedly prevented MeH-induced ROS generation and decreased cell viability in RIN-m5F cells. Furthermore, pretreatment of cells with SP600125 (JNK inhibitor; 10 μM) or NAC (1 mM) or transfection with JNK-specific siRNA obviously attenuated the MeHg-induced JNK phosphorylation, CHOP and XBP-1 protein expression, apoptotic events, and insulin secretion dysfunction. NAC significantly inhibited MeHg-activated JNK signaling, but SP600125 could not effectively reduce MeHg-induced ROS generation. Collectively, these findings demonstrate that the induction of ROS-activated JNK signaling is a crucial mechanism underlying MeHg-induced mitochondria- and ER stress-dependent apoptosis, ultimately leading to β-cell death.

Synergistic inhibition of the growth of MDA‑MB‑231 cells in triple‑negative breast cancer by salinomycin combined with 17‑AAG and its mechanism

Salinomycin (SAL), a typical ion carrier antibiotic, inhibits tumor growth and metastasis by inducing apoptosis or autophagy in cancer or cancer stem cells and thus overcomes drug resistance. 17-allylamino-17-demethoxygeldanamycin (17-AAG), a heat shock protein Hsp90 competitive inhibitor, also has a role in inhibiting tumor development. However, their combination on the growth of breast cancer cells and its specific mechanism remains to be elucidated. The present study tested the influence of SAL and 17-AAG on cell growth, apoptosis and autophagy by MTT assays, Annexin V-FITC and propidium iodide double staining assay and immunoelectron microscopy. The influence of SAL and 17-AAG on proteomics was investigated by isobaric tag for relative and absolute quantitation. It was found that SAL combined with 17-AAG synergistically inhibited the cell growth and induced the apoptosis in a concentration-dependent manner, with the expression of caspase 3 and Bcl-2 were decreased while the expression of Bax was increased. In addition, SAL combined with 17-AAG inhibited autophagy, with the expression of microtubule-associated protein 1 light chain 3, Beclin1, p62 being decreased. Mechanistically, SAL combined with 17-AAG synergistically inhibited the reactive oxygen species/JNK signaling pathway. In conclusion, SAL combined with 17-AAG had a synergistic inhibitory effect on cell growth of breast cancer via inducing apoptosis and inhibiting autophagy. The present study might provide a new strategy for potential clinical application of SAL as a new anti-tumor drug especially as a drug combination with other molecular targeting therapeutics.

JNK-dependent phosphorylation and nuclear translocation of EGR-1 promotes cardiomyocyte apoptosis

Myocardial apoptosis induced by myocardial ischemia and hyperlipemia are the main causes of high mortality of cardiovascular diseases. It is not clear whether there is a common mechanism responsible for these two kinds of cardiomyocyte apoptosis. Previous studies demonstrated that early growth response protein 1 (EGR-1) has a pro-apoptotic effect on cardiomyocytes under various stress conditions. Here, we found that EGR-1 is also involved in cardiomyocyte apoptosis induced by both ischemia and high-fat, but how EGR-1 enters the nucleus and whether nuclear EGR-1 (nEGR-1) has a universal effect on cardiomyocyte apoptosis are still unknown. By analyzing the phosphorylation sites and nucleation information of EGR-1, we constructed different mutant plasmids to confirm that the nucleus location of EGR-1 requires Ser501 phosphorylation and regulated by JNK. Furthermore, the pro-apoptotic effect of nEGR-1 was further explored through genetic methods. The results showed that EGR-1 positively regulates the mRNA levels of apoptosis-related proteins (ATF2, CTCF, HAND2, ELK1), which may be the downstream targets of EGR-1 to promote the cardiomyocyte apoptosis. Our research announced the universal pro-apoptotic function of nEGR-1 and explored the mechanism of its nucleus location in cardiomyocytes, providing a new target for the "homotherapy for heteropathy" to cardiovascular diseases.

Palmitate Enhances the Efficacy of Cisplatin and Doxorubicin against Human Endometrial Carcinoma Cells

Endometrial cancer is the most common gynecological cancer worldwide. At present there is no effective screening test for its early detection and no curative treatment for women with advanced-stage or recurrent disease. Overexpression of fatty acid synthase is a common molecular feature of a subgroup of sex steroid-related cancers associated with poor prognoses, including endometrial cancers. Disruption of this fatty acid synthesis leads to cell apoptosis, making it a potential therapeutic target. The saturated fatty acid palmitate reportedly induces lipotoxicity and cell death by inducing oxidative stress in many cell types. Here, we explored the effects of palmitate combined with doxorubicin or cisplatin in the HEC-1-A and RL95-2 human endometrial cancer cell lines. The results showed that physiological concentrations of exogenous palmitate significantly increased cell cycle arrest, DNA damage, autophagy, and apoptosis in both RL95-2 and HEC-1-A cells. It also increased the chemosensitivity of both cell types. Notably, we did not observe that palmitate lipotoxicity reflected increased levels of reactive oxygen species, suggesting palmitate acts via a different mechanism in endometrial cancer. This study thus provides a potential therapeutic strategy in which palmitate is used as an adjuvant in the treatment of endometrial cancer.

A concise review on the role of selenium for bone cancer applications

Cancer is one of the most challenging health problems in the world. Several clinical treatments have been developed, but all presenting several limitations. Among different types of cancer, bone cancer is less common, and limited new clinical treatment strategies have been proposed. Recently, a range of advanced materials has been investigated and applied for bone cancer treatment applications. However, due to the unique physiological properties of the bone tissue (a load-bearing tissue), the selection of the right type of material or the combination of suitable functional materials and base materials are critical. Selenium has been reported to present specific targeting inhibition effects on bone cancer without affecting the surrounding healthy tissue, revealing a huge potential for the development of new bone cancer treatment strategies. This paper presents a concise review on the use of selenium for bone cancer applications, discussing main synthesis methods, biocompatibility, and cytotoxicity aspects and the combination of selenium with a wide range of ceramics, metals, and polymers. Future perspectives and the novel concept of a dual-functional scaffold for both cancer treatment and new bone regeneration are also discussed.

Rosmarinic acid attenuates acrylamide induced apoptosis of BRL-3A cells by inhibiting oxidative stress and endoplasmic reticulum stress

Acrylamide (AA) is a common endogenous contaminant in food, with a complex toxicity mechanism. The study on liver damage to experimental animals caused by AA has aroused a great attention. Rosmarinic acid (RosA) as a natural antioxidant shows excellent protective effects against AA-induced hepatotoxicity, but the potential mechanism is still unclear. In the current study, the protective effect of RosA on BRL-3A cell damage induced by AA was explored. RosA increased the activity of SOD and GSH, reduced the content of ROS and MDA, and significantly reduced the oxidative stress (OS) damage of BRL-3A cells induced by AA. RosA pretreatment inhibited the MAPK signaling pathway activated by AA, and down-regulated the phosphorylation of JNK, ERK and p38. RosA pretreatment also reduced the production of calcium ions caused by AA. In addition, the key proteins p-IRE1α, XBP-1s, TRAF2 of the IRE1 pathway, and the expression of endoplasmic reticulum stress (ERS) characteristic proteins GRP78, p-ASK1, Caspase-12 and CHOP were also down-regulated by RosA. NAC blocked the activation of the MAPK signaling pathway and inhibited the ERS pathway. RosA reduced the rate of apoptosis and down-regulated the expression of Bax/Bcl-2 and Caspase-3, thereby inhibiting AA-induced apoptosis. In conclusion, RosA reduced the OS and ERS induced by AA in BRL-3A cells, thereby inhibiting cell apoptosis, and it could be used as a potential protective agent against AA toxicity.

Protective effects of klotho on palmitate-induced podocyte injury in diabetic nephropathy

The anti-aging gene, klotho, has been identified as a multi-functional humoral factor and is implicated in multiple biological processes. However, the effects of klotho on podocyte injury in diabetic nephropathy are poorly understood. Thus, the current study aims to investigate the renoprotective effects of klotho against podocyte injury in diabetic nephropathy. We examined lipid accumulation and klotho expression in the kidneys of diabetic patients and animals. We stimulated cultured mouse podocytes with palmitate to induce lipotoxicity-mediated podocyte injury with or without recombinant klotho. Klotho level was decreased in podocytes of lipid-accumulated obese diabetic kidneys and palmitate-treated mouse podocytes. Palmitate-treated podocytes showed increased apoptosis, intracellular ROS, ER stress, inflammation, and fibrosis, and these were significantly attenuated by klotho administration. Klotho treatment restored palmitate-induced downregulation of the antioxidant molecules, Nrf2, Keap1, and SOD1. Klotho inhibited the phosphorylation of FOXO3a, promoted its nuclear translocation, and then upregulated MnSOD expression. In addition, klotho administration attenuated palmitate-induced cytoskeleton changes, decreased nephrin expression, and increased TRPC6 expression, eventually improving podocyte albumin permeability. These results suggest that klotho administration prevents palmitate-induced functional and morphological podocyte injuries, and this may indicate that klotho is a potential therapeutic agent for the treatment of podocyte injury in obese diabetic nephropathy.

DGAT1 inhibitors protect pancreatic β-cells from palmitic acid-induced apoptosis

Previous studies demonstrated that prolonged exposure to elevated levels of free fatty acids (FFA), especially saturated fatty acids, could lead to pancreatic β-cell apoptosis, which plays an important role in the progression of type 2 diabetes (T2D). Diacylglycerol acyltransferase 1 (DGAT1), an enzyme that catalyzes the final step of triglyceride (TG) synthesis, has been reported as a novel target for the treatment of multiple metabolic diseases. In this study we evaluated the potential beneficial effects of DGAT1 inhibitors on pancreatic β-cells, and further verified their antidiabetic effects in db/db mice. We showed that DGAT1 inhibitors (4a and LCQ908) at the concentration of 1 μM significantly ameliorated palmitic acid (PA)-induced apoptosis in MIN6 pancreatic β-cells and primary cultured mouse islets; oral administration of a DGAT1 inhibitor (4a) (100 mg/kg) for 4 weeks significantly reduced the apoptosis of pancreatic islets in db/db mice. Meanwhile, 4a administration significantly decreased fasting blood glucose and TG levels, and improved glucose tolerance and insulin tolerance in db/db mice. Furthermore, we revealed that pretreatment with 4a (1 μM) significantly alleviated PA-induced intracellular lipid accumulation, endoplasmic reticulum (ER) stress, and proinflammatory responses in MIN6 cells, which might contribute to the protective effects of DGAT1 inhibitors on pancreatic β-cells. These findings provided a better understanding of the antidiabetic effects of DGAT1 inhibitors.

The Effects of Selenium in Acrylamide-Induced Nephrotoxicity in Rats: Roles of Oxidative Stress, Inflammation, Apoptosis, and DNA Damage

We sought to determine the effects of selenium (Se) on acrylamide (ACR)-induced nephrotoxicity in rats. In our study, 50 adult male Sprague-Dawley rats weighing 200-250 g were randomly divided into five groups. The control group was given intra-gastric (i.g.) saline (1 mL) for 10 days. The ACR group was given i.g. ACR in saline (38.27 mg/kg titrated to 1 mL) for 10 days. The Se0.5 + ACR and Se1 + ACR groups were administered Se in saline (0.5 and 1 mg/kg, respectively) for 10 days and given i.g. ACR (38.27 mg/kg) one hour after the Se injections. The Se1 group was administered i.g. Se (1 mg/kg) for 10 days. On day 11, intracardiac blood samples were obtained from the rats while they were under anesthesia, after which they were euthanized by decapitation. Urea and creatinine concentrations of blood serum samples were analyzed with an autoanalyzer. Enzyme-linked immunosorbence immunosorbent assay (ELISA) was used to quantify malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GPx), catalase (CAT), tumor necrosis factor-α (TNF-α), nuclear factor-κB (NF-κB), interleukin (IL)-33, IL-6, IL-1β, cyclooxygenase-2 (COX-2), kidney injury molecule-1 (KIM-1), mitogen-activated protein kinase-1 (MAPK-1), and caspase-3 in kidney tissues. Renal tissues were evaluated by histopathological and immunohistochemical examinations for 8-hydroxylo-2'-deoxyguanosin 8-hydroxy-2'-deoxyguanosine (8-OhDG) and Bax. Serum urea and creatinine levels were higher in the ACR group than in the control, and these ACR-induced increases were prevented by high doses of Se. Additionally, ACR induced the renal oxidative stress, inflammation, apoptosis, and damage to DNA and tissue; likewise, these were prevented by high doses of Se. Taken with ACR, Se confers protection against ACR-induced nephrotoxicity in rats by reducing oxidative stress, inflammation, apoptosis, and DNA damage.

The involvement of protein kinases in the cardioprotective effect of chronic hypoxia

The purpose of this review is to analyze the involvement of protein kinases in the cardioprotective mechanism induced by chronic hypoxia. It has been reported that chronic intermittent hypoxia contributes to increased expression of the following kinases in the myocardium: PKCdelta, PKCalpha, p-PKCepsilon, p-PKCalpha, AMPK, p-AMPK, CaMKII, p-ERK1/2, p-Akt, PI3-kinase, p-p38, HK-1, and HK-2; whereas, chronic normobaric hypoxia promotes increased expression of the following kinases in the myocardium: PKCepsilon, PKCbetaII, PKCeta, CaMKII, p-ERK1/2, p-Akt, p-p38, HK-1, and HK-2. However, CNH does not promote enhanced expression of the AMPK and JNK kinases. Adaptation to hypoxia enhances HK-2 association with mitochondria and causes translocation of PKCdelta, PKCbetaII, and PKCeta to the mitochondria. It has been shown that PKCdelta, PKCepsilon, ERK1/2, and MEK1/2 are involved in the cardioprotective effect of chronic hypoxia. The role of other kinases in the cardioprotective effect of adaptation to hypoxia requires further research.

A novel low systemic diacylglycerol acyltransferase 1 inhibitor, Yhhu2407, improves lipid metabolism

Diacylglycerol acyltransferase 1 (DGAT1) plays a pivotal role in lipid metabolism by catalyzing the committed step in triglyceride (TG) synthesis and has been considered as a potential therapeutic target of multiple metabolic diseases, including dyslipidemia, obesity and type 2 diabetes. Here we report a novel DGAT1 inhibitor, Yhhu2407, which showed a stronger DGAT1 inhibitory activity (IC₅₀ = 18.24 ± 4.72 nM) than LCQ908 (IC₅₀ = 78.24 ± 8.16 nM) in an enzymatic assay and led to a significant reduction in plasma TG after an acute lipid challenge in mice. Pharmacokinetic studies illustrated that Yhhu2407 displayed a low systemic, liver- and intestine-targeted distribution pattern, which is consistent with the preferential tissue expression pattern of DGAT1 and therefore might help to maximize the beneficial pharmacological effects and prevent the occurrence of side effects. Cell-based investigations demonstrated that Yhhu2407 inhibited free fatty acid (FFA)-induced TG accumulation and apolipoprotein B (ApoB)-100 secretion in HepG2 cells. In vivo study also disclosed that Yhhu2407 exerted a beneficial effect on regulating plasma TG and lipoprotein levels in rats, and effectively ameliorated high-fat diet (HFD)-induced dyslipidemia in hamsters. In conclusion, we identified Yhhu2407 as a novel DGAT1 inhibitor with potent efficacy on improving lipid metabolism in rats and HFD-fed hamsters without causing obvious adverse effects.

The inhibition of reactive oxygen species (ROS) by antioxidants inhibits the release of an autophagy marker in ectopic endometrial cells

OBJECTIVE

The aim of this study was to evaluate the role of oxidative stress and reactive oxygen species (ROS) in the pathogenesis of endometriosis (EMs) and to investigate the role of antioxidant therapy on autophagy and the outcome of EMs.

MATERIALS AND METHODS

Experimental rats were given an peritoneal perfusion of N-acetyl-l-cysteine (NAC, 200 mg/kg) or catalase (CAT, 2000 U/mL). Immunofluorescence was then used to detect microtubule-associated protein light chain 3 (LC3). Western blotting was used to determine the levels of Beclin-1 protein while enzyme-linked immunosorbent assays (ELISAs) were used to measure ROS levels after treatment.

RESULTS

Fluorescent in situ hybridization showed that NAC and CAT influenced the levels of LC3, an autophagy marker; there were significantly lower levels of LC3 fluorescence in the EMs group (surgical group) of rats compared with controls (p < 0.05). Western blot analysis revealed a downregulation of Beclin-1 protein in both the NAC and CAT groups (p < 0.05) while ELISA revealed significantly lower levels of ROS in the NAC and CAT groups (p < 0.05).

CONCLUSION

The antioxidants NAC and CAT significantly reduced levels of the autophagy marker LC3 and caused levels of Beclin-1 to significantly decrease. Consequently, antioxidant therapy shows potential for the future treatment of EMs.

Palmitate differentially regulates Spexin, and its receptors Galr2 and Galr3, in GnRH neurons through mechanisms involving PKC, MAPKs, and TLR4

The function of the gonadotropin-releasing hormone (GnRH) neuron is critical to maintain reproductive function and a significant decrease in GnRH can lead to disorders affecting fertility, including hypogonadotropic hypogonadism. Spexin (SPX) is a novel hypothalamic neuropeptide that exerts inhibitory effects on reproduction and feeding by acting through galanin receptor 2 (GALR2) and galanin receptor 3 (GALR3). Fatty acids can act as nutritional signals that regulate the hypothalamic-pituitary-gonadal (HPG) axis, and elevated levels of circulating saturated fatty acids associated with high fat diet (HFD)-feeding have been shown to induce neuroinflammation, endoplasmic reticulum stress and hormonal resistance in the hypothalamus, as well as alter neuropeptide expression. We previously demonstrated that palmitate, the most common saturated fatty acid in a HFD, elevates the expression of Spx, Galr2 and Galr3 mRNA in a model of appetite-regulating neuropeptide Y hypothalamic neurons. Here, we found that Spx, Galr2 and Galr3 mRNA were also significantly induced by palmitate in a model of reproductive GnRH neurons, mHypoA-GnRH/GFP. As a follow-up to our previous report, we examined the molecular pathways by which Spx and galanin receptor mRNA was regulated in this cell line. Furthermore, we performed inhibitor studies, which revealed that the effect of palmitate on Spx and Galr3 mRNA involved activation of the innate immune receptor TLR4, and we detected differential regulation of the three genes by the protein kinases PKC, JNK, ERK, and p38. However, the intracellular metabolism of palmitate to ceramide did not appear to be involved in the palmitate-mediated gene regulation. Overall, this suggests that SPX may play a role in reproduction at the level of the hypothalamus and the pathways by which Spx, Galr2 and Galr3 are altered by fatty acids could provide insight into the mechanisms underlying reproductive dysfunction in obesity.

Activation of the AMPK-SIRT1 pathway contributes to protective effects of Salvianolic acid A against lipotoxicity in hepatocytes and NAFLD in mice

Background: Salvianolic acid A (Sal A), a natural polyphenol compound extracted from Radix Salvia miltiorrhiza (known as Danshen in China), possesses a variety of potential pharmacological activities. The aim of this study is to determine mechanisms of hepatoprotective effects of Sal A against lipotoxicity both in cultured hepatocytes and in a mouse model of fatty liver disease. Methods: High-fat and high-carbohydrate diet (HFCD)-fed C57BL/6J mice were employed to establish hepatic lipotoxicity in a mouse model. Two doses of Sal A were administered every other day via intraperitoneal injection (20 and 40 mg/kg BW, respectively). After a 10-week intervention, liver injury was detected by immunohistochemical and biochemical analyses. For in vitro studies, we used HepG2, a human hepatoma cell line, and exposed them to palmitic acid to induce lipotoxicity. The protective effects of Sal A on palmitic acid-induced lipotoxicity were examined in Sal A-pretreated HepG2 cells. Results: Sal A treatments attenuated body weight gain, liver injury, and hepatic steatosis in mice exposed to HFCD. Sal A pretreatments ameliorated palmitic acid-induced cell death but did not reverse effects of HFCD- or palmitate-induced activations of JNK, ERK1/2, and PKA. Induction of p38 phosphorylation was significantly reversed by Sal A in HFCD-fed mice but not in palmitate-treated HepG2 cells. However, Sal A rescued hepatic AMP-activated protein kinase (AMPK) suppression and sirtuin 1 (SIRT1) downregulation by both HFCD feeding in mice and exposure to palmitate in HepG2 cells. Sal A dose-dependently up-regulated p-AMPK and SIRT1 protein levels. Importantly, siRNA silencing of either AMPK or SIRT1 gene expression abolished the protective effects of Sal A on lipotoxicity. Moreover, while AMPK silencing blocked Sal A-induced SIRT1, silencing of SIRT1 had no effect on Sal A-triggered AMPK activation, suggesting SIRT1 upregulation by Sal A is mediated by AMPK activation. Conclusion: Our data uncover a novel mechanism for hepatoprotective effects of Sal A against lipotoxicity both in livers from HFCD-fed mice and palmitic acid-treated hepatocytes.

Hepatic metabolic adaptation and adipose tissue expansion are altered in mice with steatohepatitis induced by high-fat high sucrose diet

BACKGROUND

Obesity is a chronic progressive disease with several metabolic alterations. Nonalcoholic fatty liver disease (NAFLD) is an important comorbidity of obesity that can progress to nonalcoholic steatohepatitis (NASH), cirrhosis or hepatocarcinoma. This study aimed at clarifying the molecular mechanisms underlying the metabolic alterations in hepatic and adipose tissue during high-fat high-sucrose diet-induced NAFLD development in mice.

METHODS

Twenty-four male mice (C57BL/6J) were randomly allocated into 3 groups (n = 8 mice per group) to receive a chow diet, a high-fat diet (HFD), or a high-fat high-sucrose diet (HF-HSD) for 20 weeks. At sacrifice, liver and adipose tissue were obtained for histopathological, metabolomic, and protein expression analyses.

RESULTS

HF-HSD (but not HFD) was associated with NASH and increased oxidative stress. These animals presented an inhibition of hepatic autophagy and alterations in AMP-activated protein kinase/mammalian target of rapamycin activity. We also observed that the ability of metabolic adaptation was adversely affected by the increase of damaged mitochondria. NASH development was associated with changes in adipose tissue dynamics and increased amounts of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids in visceral adipose tissue.

CONCLUSION

HF-HSD led to a metabolic blockage and impaired hepatic mitochondria turnover. In addition, the continuous accumulation of fatty acids produced adipose tissue dysfunction and hepatic fat accumulation that favored the progression to NASH.

Effect and mechanism of asiatic acid on autophagy in myocardial ischemia-reperfusion injury and

Myocardial ischemia-reperfusion injury (MIRI) is a major cause of heart failure in patients with coronary heart disease. The excessive accumulation of reactive oxygen species (ROS) during MIRI induces the overactivation of an autophagic response, which aggravates myocardial cell damage. Asiatic acid (AA) is a triterpenoid compound, which is extracted from Centella asiatica and exhibits a variety of pharmacological effects such as hepatoprotective, neuroprotective and antioxidant. However, the association of AA with autophagy in MIRI is not fully understood. In the present study, the positive effects of AA in MIRI injury were determined via establishing a MIRI mouse model. Pre-treatment with AA was indicated to improve cardiac function and decrease cardiomyocyte autophagy in mice subjected to MIRI. To examine the protective effects of AA and the underlying mechanisms in MIRI, a cardiomyocyte glucose deprivation/reperfusion (OGD) model was established. The administration of AA decreased the levels of ROS and malondialdehyde and increased the levels of superoxide dismutase activity in OGD-treated cells. Using western blotting, it was demonstrated that treatment with AA decreased the phosphorylation of p38 and increased the expression of Bcl-2 in OGD-treated cells. Additionally, the expression of autophagy markers, including beclin-1 and the microtubule-associated proteins 1A/1B light chain 3B II/I ratio, were also decreased in AA treated cells compared with OGD-treated cells. These results demonstrated that AA pretreatment protected cardiomyocytes from ROS-mediated autophagy via a p38 mitogen-activated protein kinase/Bcl-2/beclin-1 signaling pathway in MIRI.

MKP-5 Relieves Lipotoxicity-Induced Islet β-Cell Dysfunction and Apoptosis via Regulation of Autophagy

Mitogen-activated protein kinase phosphatase-5 (MKP-5) is a regulator of extracellular signaling that is known to regulate lipid metabolism. In this study, we found that obesity caused by a high-fat diet (HFD) decreased the expression of MKP-5 in the pancreas and primary islet cells derived from mice. Then, we further investigated the role of MKP-5 in the protection of islet cells from lipotoxicity by modulating MKP-5 expression. As a critical inducer of lipotoxicity, palmitic acid (PA) was used to treat islet β-cells. We found that MKP-5 overexpression restored PA-mediated autophagy inhibition in Rin-m5f cells and protected these cells from PA-induced apoptosis and dysfunction. Consistently, a lack of MKP-5 aggravated the adverse effects of lipotoxicity. Islet cells from HFD-fed mice were infected using recombinant adenovirus expressing MKP-5 (Ad-MKP-5), and we found that Ad-MKP-5 was able to alleviate HFD-induced apoptotic protein activation and relieve the HFD-mediated inhibition of functional proteins. Notably, HFD-mediated impairments in autophagic flux were restored by Ad-MKP-5 transduction. Furthermore, the autophagy inhibitor 3-methyladenine (3-MA) was used to treat Rin-m5f cells, confirming that the MKP-5 overexpression suppressed apoptosis, dysfunction, inflammatory response, and oxidative stress induced by PA via improving autophagic signaling. Lastly, employing c-Jun amino-terminal kinas (JNK), P38, or extracellular-regulated kinase (ERK) inhibitors, we established that the JNK and P38 MAPK pathways were involved in the MKP-5-mediated apoptosis, dysfunction, and autophagic inhibition observed in islet β cells in response to lipotoxicity.

Andrographolide sensitizes Hep-2 human laryngeal cancer cells to carboplatin-induced apoptosis by increasing reactive oxygen species levels

Andrographolide is a natural diterpenoid from Andrographis paniculata that has been proposed as an anticancer agent as well as a chemosensitizer for use in combination with anticancer drugs. Carboplatin is the first-line chemotherapeutic agent for advanced laryngeal carcinoma. However, the clinical efficacy of carboplatin is limited by drug resistance and side effects. The aim of this study was to investigate whether andrographolide has a synergistic antitumor effect with carboplatin on human laryngeal cancer cells. Hep-2 cells were exposed to andrographolide with or without carboplatin. The effects of indicated therapies were examined using the Cell Counting Kit-8 assay, the colony-forming assay, the Hoechst 33342/PI double staining, and flow cytometry analysis. The molecular mechanism was assessed by reactive oxygen species (ROS) detection and western blot. At the sublethal concentration, andrographolide increased carboplatin sensitivity of Hep-2 cells by increasing carboplatin-induced apoptosis and inhibiting cell viability. Moreover, we found that andrographolide sensitized carboplatin mainly through the induction of ROS generation and apoptotic signaling. Taken together, these results indicate that andrographolide, along with carboplatin, synergistically inhibited cell proliferation and induced mitochondrial apoptosis of Hep-2 cells by increasing the intracellular ROS, regulating the mitogen-activated protein kinase and phosphatidylinositol 3-kinase (PI3K/AKT) pathways, altering the BCL2/BAX ratio, and ultimately activating the cleavage of Caspase-3 and PARP. These results suggest that andrographolide sensitizes human laryngeal cancer cells to carboplatin-induced apoptosis by increasing ROS levels.

Cerium Oxide Nanoparticles Regulate Osteoclast Differentiation Bidirectionally by Modulating the Cellular Production of Reactive Oxygen Species

BACKGROUND

Cerium oxide nanoparticles (CeO2NPs) are potent scavengers of cellular reactive oxygen species (ROS). Their antioxidant properties make CeO2NPs promising therapeutic agents for bone diseases and bone tissue engineering. However, the effects of CeO2NPs on intracellular ROS production in osteoclasts (OCs) are still unclear. Numerous studies have reported that intracellular ROS are essential for osteoclastogenesis. The aim of this study was to explore the effects of CeO2NPs on osteoclast differentiation and the potential underlying mechanisms.

METHODS

The bidirectional modulation of osteoclast differentiation by CeO2NPs was explored by different methods, such as fluorescence microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting. The cytotoxic and proapoptotic effects of CeO2NPs were detected by cell counting kit (CCK-8) assay, TdT-mediated dUTP nick-end labeling (TUNEL) assay, and flow cytometry.

RESULTS

The results of this study demonstrated that although CeO2NPs were capable of scavenging ROS in acellular environments, they facilitated the production of ROS in the acidic cellular environment during receptor activator of nuclear factor kappa-Β ligand (RANKL)-dependent osteoclast differentiation of bone marrow-derived macrophages (BMMs). CeO2NPs at lower concentrations (4.0 µg/mL to 8.0 µg/mL) promoted osteoclast formation, as shown by increased expression of Nfatc1 and C-Fos, F-actin ring formation and bone resorption. However, at higher concentrations (greater than 16.0 µg/mL), CeO2NPs inhibited osteoclast differentiation and promoted apoptosis of BMMs by reducing Bcl2 expression and increasing the expression of cleaved caspase-3, which may be due to the overproduction of ROS.

CONCLUSION

This study demonstrates that CeO2NPs facilitate osteoclast formation at lower concentrations while inhibiting osteoclastogenesis in vitro by inducing the apoptosis of BMMs at higher concentrations by modulating cellular ROS levels.

PEITC triggers multiple forms of cell death by GSH-iron-ROS regulation in K7M2 murine osteosarcoma cells

Phenethyl isothiocyanate (PEITC) is an isothiocyanate that largely exists in cruciferous vegetables and exhibits chemopreventive and chemotherapeutic potential against various cancers. However, it is little known about the molecular mechanisms of its antitumor action against osteosarcoma, which is the second highest cause of cancer-related death in children and adolescents. In this study, we investigated the effects of PEITC on K7M2 murine osteosarcoma both in vitro and in vivo. We found that treatment with PEITC dose-dependently inhibited the viability of K7M2 murine osteosarcoma cells with an IC50 value of 33.49 μM at 24 h. PEITC (1, 15, 30 μM) dose-dependently inhibited the cell proliferation, caused G2/M cell cycle arrest, depleted glutathione (GSH), generated reactive oxygen species (ROS), altered iron metabolism, and triggered multiple forms of cell death, namely ferroptosis, apoptosis, and autophagy in K7M2 cells. We further revealed that PEITC treatment activated MAPK signaling pathway, and ROS generation was a major cause of PEITC-induced cell death. In a syngeneic orthotopic osteosarcoma mouse model, administration of PEITC (30, 60 mg/kg every day, ig, for 24 days) significantly inhibited the tumor growth, but higher dose of PEITC (90 mg/kg every day) compromised its anti-osteosarcoma effect. Histological examination showed that multiple cell death processes were initiated, iron metabolism was altered and MAPK signaling pathway was activated in the tumor tissues. In conclusion, we demonstrate that PEITC induces ferroptosis, autophagy, and apoptosis in K7M2 osteosarcoma cells by activating the ROS-related MAPK signaling pathway. PEITC has promising anti-osteosarcoma activity. This study sheds light on the redox signaling-based chemotherapeutics for cancers.

Hyperoside alleviates epilepsy-induced neuronal damage by enhancing antioxidant levels and reducing autophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Hypericum perforatum L. (genus Hypericum, family Hypericaceae), a plant commonly used in traditional Chinese medicine, is believed to confer a wide range of benefits, including fever reduction, detoxification, calming, and pain relief via decoctions of its stems and leaves. Hyperoside (HYP), a natural compound extracted from Hypericum perforatum L., has been shown to demonstrate a wide array of bioactivities including antioxidative, anti-inflammatory, and anti-apoptotic effects. In this study, we investigated the effects of HYP on epilepsy-induced neuronal damage in mice and the associated regulatory factors.

AIM OF THE STUDY

This study examined the potential therapeutic use of HYP for the treatment of neuronal damage in a mouse model of epilepsy and explored the relationships of the potential neuroprotective effects of HYP pretreatment with antioxidant levels and autophagy.

MATERIALS AND METHODS

ICR mice were randomly divided into six groups: sham group, sham-HYP group, KA group, KA-HYP group, KA-HYP-DDC group and KA-CQ group. Immunohistochemical staining was used to assess changes in NeuN, IBA-1, and GFAP expression in the CA3 region of the hippocampus. Immunofluorescence staining was used to assess the effects of HYP on the number of autophagosomes that accumulated in neurons in the hippocampal CA3 region. The levels of SOD1, SOD2, LC3I/II, Beclin1, and PI3K/AKT and MAPK signaling-related proteins were detected by Western blot.

RESULTS

Pretreatment with 50 mg/kg HYP protected against epilepsy-induced neuronal damage in the hippocampal CA3 region. Additionally, HYP enhanced antioxidant levels and reduced the levels of autophagy-related proteins via the PI3K/AKT and MAPK pathways.

CONCLUSION

HYP protected the hippocampal CA3 region against epilepsy-induced neuronal damage via enhancing antioxidant levels and reducing autophagy. The mechanism of action may be related to the maintenance of antioxidant levels and the suppression of autophagy via the PI3K/Akt and MAPK pathways.

IL-24-Armed Oncolytic Vaccinia Virus Exerts Potent Antitumor Effects via Multiple Pathways in Colorectal Cancer

Colorectal cancer is an aggressive malignancy for which there are limited treatment options. Oncolytic vaccinia virus is being developed as a novel strategy for cancer therapy. Arming vaccinia virus with immunostimulatory cytokines can enhance the tumor cell-specific replication and antitumor efficacy. Interleukin-24 (IL-24) is an important immune mediator, as well as a broad-spectrum tumor suppressor. We constructed a targeted vaccinia virus of Guang9 strain harboring IL-24 (VG9-IL-24) to evaluate its antitumor effects. In vitro, VG9-IL-24 induced an increased number of apoptotic cells and blocked colorectal cancer cells in the G₂/M phase of the cell cycle. VG9-IL-24 induced apoptosis in colorectal cancer cells via multiple apoptotic signaling pathways. In vivo, VG9-IL-24 significantly inhibited the tumor growth and prolonged the survival both in human and murine colorectal cancer models. In addition, VG9-IL-24 stimulated multiple antitumor immune responses and direct bystander antitumor activity. Our results indicate that VG9-IL-24 can inhibit the growth of colorectal cancer tumor by inducing oncolysis and apoptosis as well as stimulating the antitumor immune effects. These findings indicate that VG9-IL-24 may exert a potential therapeutic strategy for combating colorectal cancer.

RGS4 controls Gαi3-mediated regulation of Bcl-2 phosphorylation on TGN38-containing intracellular membranes

Intracellular pools of the heterotrimeric G-protein α-subunit Gαi3 (encoded by GNAI3) have been shown to promote growth factor signaling, while at the same time inhibiting the activation of JNK and autophagic signaling following nutrient starvation. The precise molecular mechanisms linking Gαi3 to both stress and growth factor signaling remain poorly understood. Importantly, JNK-mediated phosphorylation of Bcl-2 was previously found to activate autophagic signaling following nutrient deprivation. Our data shows that activated Gαi3 decreases Bcl-2 phosphorylation, whereas inhibitors of Gαi3, such as RGS4 and AGS3 (also known as GPSM1), markedly increase the levels of phosphorylated Bcl-2. Manipulation of the palmitoylation status and intracellular localization of RGS4 suggests that Gαi3 modulates phosphorylated Bcl-2 levels and autophagic signaling from discreet TGN38 (also known as TGOLN2)-labeled vesicle pools. Consistent with an important role for these molecules in normal tissue responses to nutrient deprivation, increased Gαi signaling within nutrient-starved adrenal glands from RGS4-knockout mice resulted in a dramatic abrogation of autophagic flux, compared to wild-type tissues. Together, these data suggest that the activity of Gαi3 and RGS4 from discreet TGN38-labeled vesicle pools are critical regulators of autophagic signaling that act via their ability to modulate phosphorylation of Bcl-2.

Cytisine exerts anti-tumour effects on lung cancer cells by modulating reactive oxygen species-mediated signalling pathways

Cytisine is a natural product isolated from plants and is a member of the quinolizidine alkaloid family. This study aims to investigate the effect of cytisine in human lung cancer. Cell viability was determined using the CCK-8 assay, and the results showed that cytisine inhibited the growth of lung cancer cell lines. The apoptotic effects were evaluated using flow cytometry, and the results showed that cytisine induced mitochondrial-dependent apoptosis through loss of the mitochondrial membrane potential; increased expression of BAD, cleaved caspase-3, and cleaved-PARP; and decreased expression levels of Bcl-2, pro-caspase-3, and pro-PARP. In addition, cytisine caused G2/M phase cell cycle arrest that was associated with inhibiting the AKT signalling pathway. During apoptosis, cytisine increased the phosphorylation levels of JNK, p38, and I-κB, and decreased the phosphorylation levels of ERK, STAT3, and NF-κB. Furthermore, cytisine treatment led to the generation of ROS, and the NAC attenuated cytisine-induced apoptosis. In vivo, cytisine administration significantly inhibited the lung cancer cell xenograft tumorigenesis. In conclusion, cytisine plays a critical role in suppressing the carcinogenesis of lung cancer cells through cell cycle arrest and induction of mitochondria-mediated apoptosis, suggesting that it may be a promising candidate for the treatment of human lung cancer.

P38-β/SAPK-inhibiting and apoptosis-inducing activities of (E)-4-chloro-2-((3-ethoxy-2-hydroxybenzylidene) amino)phenol

The present study has three purposes; first evaluating cytotoxicity of (E)-4-chloro-2-((3-ethoxy-2-hydroxybenzylidene)amino)phenol (ACES), second deciphering ACES-mediated cellular death mechanism, and third estimating ACES-mediated alterations in the expressions of mitogen-activated protein kinase (MAPK) pathway-related genes. Neutral red uptake assay, cell cycle analysis, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) measurements, caspase 3/7 and 9 activations, and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) were implemented. IC₅₀ values of ACES-treated five cells were around 4-6 µg/mL. However, Caco-2 and Huh-7 cells were found to be twofold resistant and fivefold sensitive with IC₅₀ values of 11 µg/mL and 0.93 µg/mL, respectively. In this study, it was initially reported that ACES exhibits selective cytotoxicity to Huh-7 cells. In addition, ACES induced apoptosis by nuclear fragmentation, MMP disruption, and intracellular ROS elevation in MCF-7 cells. qRT-PCR experiment indicated the expressions of 30 genes including ATF2, CREB1, MYC, NFATC4 (NFAT3), CCNA1, CCNB1, CCND2, CDK2, CDKN1A (p21CIP1), CDKN1C (p57KIP2), CDKN2A (p16INK4a), CDKN2B (p15INK4b), DLK1, NRAS, CDC42, PAK1, MAP4K1 (HPK1), MAP3K3 (MEKK3), MAP2K3 (MEK3), MAP2K6 (MEK6), MOS, MAPK1 (ERK2), MAPK8 (JNK1), MAPK10 (JNK3), MAPK11 (p38-β), LAMTOR3 (MP1), MAPK8IP2 (JIP-1), PRDX6 (AOP2), COL1A1, and HSPA5 (Grp78) were downregulated at least 1.5-fold. Moreover, ACES effectively inhibited expressions of genes that code for elements of p38-β/stress-activated protein kinase (SAPK) pathway. ACES has the potential to be used for the reversal of trastuzumab resistance in breast cancer patients by inhibiting p38/SAPK pathway in MCF-7 cells. Therefore, with the selective cytotoxic, apoptosis-inducing, and p38-β/SAPK-inhibiting activities, ACES can be utilized for developing a novel anticancer drug.

GPAT4-Generated Saturated LPAs Induce Lipotoxicity through Inhibition of Autophagy by Abnormal Formation of Omegasomes

Excessive levels of saturated fatty acids are toxic to vascular smooth muscle cells (VSMCs). We previously reported that mice lacking VSMC-stearoyl-CoA desaturase (SCD), a major enzyme catalyzing the detoxification of saturated fatty acids, develop severe vascular calcification from the massive accumulation of lipid metabolites containing saturated fatty acids. However, the mechanism by which SCD deficiency causes vascular calcification is not completely understood. Here, we demonstrate that saturated fatty acids significantly inhibit autophagic flux in VSMCs, contributing to vascular calcification and apoptosis. Mechanistically, saturated fatty acids are accumulated as saturated lysophosphatidic acids (LPAs) (i.e. 1-stearoyl-LPA) possibly synthesized through the reaction of GPAT4 at the contact site between omegasomes and the MAM. The accumulation of saturated LPAs at the contact site causes abnormal formation of omegasomes, resulting in accumulation of autophagosomal precursor isolation membranes, leading to inhibition of autophagic flux. Thus, saturated LPAs are major metabolites mediating autophagy inhibition and vascular calcification.

Cilostazol alleviate nicotine induced cardiomyocytes hypertrophy through modulation of autophagy by CTSB/ROS/p38MAPK/JNK feedback loop

Nicotine is proved to be an important factor for cardiac hypertrophy. Autophagy is important cell recycling system involved in the regulation of cardiac hypertrophy. Cilostazol, which is often used in the management of peripheral vascular disease. However, the effects of cilostazol on nicotine induced autophagy and cardiac hypertrophy are unclear. Here, we aim to determine the role and molecular mechanism of cilostazol in alleviating nicotine-induced cardiomyocytes hypertrophy through modulating autophagy and the underlying mechanisms. Our results clarified that nicotine stimulation caused cardiomyocytes hypertrophy and autophagy flux impairment significantly in neonatal rat ventricular myocytes (NRVMs), which were evidenced by augments of LC3-II and p62 levels, and impaired autophagosomes clearance. Interestingly, cathepsin B (CTSB) activity decreased dramatically after stimulation with nicotine in NRVMs, which was crucial for substrate degradation in the late stage of autophagy process, and cilostazol could reverse this effect dramatically. Intracellular ROS levels were increased significantly after nicotine exposure. Meanwhile, p38MAPK and JNK were activated after nicotine treatment. By using ROS scavenger N-acetyl-cysteine (NAC) could reverse the effects of nicotine by down-regulation the phosphorylation of p38MAPK and JNK pathways, and pretreatment of specific inhibitors of p38MAPK and JNK could restore the autophagy impairment and cardiomyocytes hypertrophy induced by nicotine. Moreover, CTSB activity of lysosome regained after the treatment with cilostazol. Cilostazol also inhibited the ROS accumulation and the activation of p38MAPK and JNK, which providing novel connection between lysosome CTSB and ROS/p38MAPK/JNK related oxidative stress pathway. This is the first demonstration that cilostazol could alleviate nicotine induced cardiomyocytes hypertrophy through restoration of autophagy flux by activation of CTSB and inhibiting ROS/p38/JNK pathway, exhibiting a feedback loop on regulation of autophagy and cardiomyocytes hypertrophy.

Juglanin administration protects skin against UVB‑induced injury by reducing Nrf2‑dependent ROS generation

Extensive solar ultraviolet B (UVB) exposure of the skin results in inflammation and oxidative stress, which may contribute to skin cancer. Natural products have attracted attention for their role in the effective treatment of cutaneous neoplasia. Juglanin is purified from the crude extract of Polygonum aviculare, exhibiting anti-oxidant, anti-inflammatory and anti-cancer activities. Jugalanin was used in the current study to investigate whether it may ameliorate UVB irradiation-induced skin damage by reducing oxidative stress and suppressing the inflammatory response in vivo and in vitro. In the present study, hairless mice were exposed to UVB irradiation in the absence or presence of juglanin administration for 10 weeks. The findings indicated that juglanin inhibited UVB-induced hyperplasia and decreased infiltration in the skin of mice. UVB exposure-induced oxidative stress in mice and cells was inhibited by juglanin via enhancing anti-oxidant activity. Additionally, juglanin markedly reduced pro-inflammatory cytokine release, including cyclic oxidase 2, interleukin-1β and tumor necrosis factor-α, triggered by chronic UVB irradiation. Juglanin-ameliorated skin damage was associated with its suppression of mitogen activated protein kinases (MAPKs), including p38, extracellular signal regulated 1/2, and c-Jun N-terminal kinases, as well as nuclear factor (NF)-κB signaling pathways, which was dependent on nuclear factor-E2-related factor 2 (Nrf2)-modulated reactive oxygen species generation. Taken together, these data indicate that juglanin protected against UVB-triggered oxidative stress and inflammatory responses by suppressing MAPK and NF-κB activation via enhancing Nrf2 activity.