Naringenin prevents high glucose-induced mitochondria-mediated apoptosis involving AIF, Endo-G and caspases

Optimization of Naringenin-loaded nanoparticles for targeting of Vanin-1, iNOS, and MCP-1 signaling pathway in HFD-induced obesity

Naringenin, a natural dihydrochalcone flavonoid, exhibits diverse pharmacological properties. This study investigates the hypolipidemic effects of Nar-NPs on obese mice. The characteristics of Nar-NPs, including morphology, particle size, zeta potential, UV-vis, and FT-IR spectra, were examined. The anti-obesity properties of Nar-NPs were evaluated in obese rats, considering LD50, 1/20 LD50, and 1/50 LD50 for treatment preparation. Results indicated that synthesized Nar-NPs were uniform, spherical, and well-dispersed, with a size of 130.06 ± 1.98 nm and with a zeta potential of -25.6 ± 0.8 mV. Nar-NPs exhibited enhancement in the cumulative release of naringenin (56.87 ± 2.45 %) as compared to pure naringenin suspension 87.83 ± 1.84 % in 24 h of the study. The LD50 of Nar-NPs was determined as 412.5 mg/kg.b.w. HFD induced elevated glycemic, oxidative stress, and inflammatory biomarkers while reducing HDL-C, GSH, and superoxide dismutase (SOD) levels. Administration of Nar-NPs significantly mitigated body weight, glucose, insulin, leptin, TC, TG, SREBP1c, pAMPK, PPAR-α, as well as vanin-1, MCP-1, and iNOS mRNA gene expression. Histological investigations supported the biochemical and PCR findings. In a nutshell, the study suggests that the Nar-NPs could serve as a promising and viable pharmacological strategy for the treatment of obesity-related disorders.

Dietary T-2 toxin induces transcriptomic changes in hepatopancreas of Chinese mitten crab (Eriocheir sinensis) via nutrition metabolism and apoptosis-related pathways

Long-term feed route exposure to T-2 toxin was proved to elicit growth retarding effects and induction of oxidative stress and apoptosis in Chinese mitten crab (Eriocheir sinensis). However, no study with a holistic perspective has been conducted to date to further describe the in-depth toxicological mechanism of T-2 toxin in E.sinensis. In this study, an RNA-Sequencing (RNA-seq) was used in this study to investigate the effects of feed supplementation with 0 mg/kg and 4 mg/kg T-2 toxin on the hepatopancreas transcriptome of E.sinensis and establish a hepatopancreas transcriptome library of T-2 toxin chronically exposed crabs after five weeks, where 14 differentially expressed genes (DEGs) were screened out across antioxidant, apoptosis, autophagy, glucolipid metabolism and protein synthesis. The actual expression of all the DEGs (Caspase, ATG4, PERK, ACSL, CAT, BIRC2, HADHA, HADHB, ACOX, PFK, eEFe1, eIF4ɑ, RPL13Ae) was also analyzed by real-time quantitative PCR (RT-qPCR). It was demonstrated that long-term intake of large amounts of T-2 toxin could impair antioxidant enzyme activity, promote apoptosis and protective autophagy, disrupt lipid metabolism and inhibit protein synthesis in the hepatopancreas of E.sinensis. In conclusion, this study explored the toxicity mechanism of T-2 toxin on the hepatopancreas of E.sinensis at the mRNA level, which lays the foundation for further investigation of the molecular toxicity mechanism of T-2 toxin in aquatic crustaceans.

Dibutyl phthalate-induced oxidative stress and apoptosis in swine testis cells and therapy of naringenin via PTEN/PI3K/AKT signaling pathway

Dibutyl phthalate (DBP) is a phthalic acid ester (PAE) that has posed a health hazard to the organisms. Naringenin (NRG) is a flavanone compound that has shown protection against several environmental chemicals through suppression of oxidative stress and activation of phosphatidylinositol 3-kinase/threonine kinase (PI3K/AKT) signaling pathway. Herein, swine testis (ST) cells were treated with 1.8 μM of DBP or/and 25.39 nM of NRG for 24 h, we described the discovery path of NRG inhibition on apoptosis in DBP-exposed ST cells through targeting phosphatase and tensin homologue deleted on chromosome 10 (PTEN). We first found that the anti-apoptosis effect of NRG is dependent on mitochondrial pathway through flow cytometry and related gene/protein expression, and then we detected PI3K/AKT pathway-related gene/protein expression, and established a computational docking assay between NRG and PTEN. We found that NRG specifically binds to three basic residues (His93, Lys125, Lys128) of P loop in PTEN, as well as phosphatase domains (Asp92, His93, Cys124, Lys125, Ala126, Lys128, and Arg130) in active dephosphorylation pockets, thereby reducing PTEN level and activating PI3K/AKT signaling pathway, and further inhibiting oxidative stress and mitochondrial pathway apoptosis. Taken together, our results push forward that NRG deserves further attention as a potential antagonistic therapy against DBP through targeting PTEN to inhibit oxidative stress and activate PI3K/AKT signaling pathway.

Naringenin Prevents Inflammation, Apoptosis, and DNA Damage in Potassium Oxonate-Induced Hyperuricemia in Rat Liver Tissue: Roles of Cytochrome C, NF-κB, Caspase-3, and 8-Hydroxydeoxyguanosine

Background: Hyperuricemia (HU) is a metabolic disease characterized by high uric acid levels in the blood. HU is a risk factor for diabetes, cardiovascular complications, metabolic syndrome, and chronic kidney disease. Purpose: The present study was performed to determine the effect of experimental HU on xanthine oxidase (XO), tumor necrosis factor-alpha (TNF-α), nuclear factor-kappa B (NF-κB), interleukin-17 (IL-17), cytochrome C, glutathione peroxidase (GPx), caspase-3, and 8-hydroxydeoxyguanosine (8-OHdG) levels in liver tissues of rats. Study Design: Thirty-five, male, Wistar albino-type rats were used for this study. Experimental groups were formed as follows: Group 1: control group; Group 2: potassium oxonate (PO) group; group 3: PO+NAR (naringenin; 2 weeks) group; and Group 4: PO (2 weeks)+NAR (2 weeks) group (total of 4 weeks). Methods: The first group was not given anything other than normal rat food and drinking water. In the second group, a 250 mg/kg intraperitoneal dose of PO was administered for 2 weeks. In the third group, 250 mg/kg intraperitoneal PO (application for 2 weeks) and 100 mg/kg NAR intraperitoneally 1 hr after each application were administered. In the fourth group, intraperitoneal PO administration was applied for 2 weeks, followed by intraperitoneal administration of NAR for 2 weeks (4 weeks in total). At the end of the experimental period, XO, TNF-α, NF-κB, IL-17, cytochrome C, GPx, caspase-3, and 8-OHdG levels were determined in liver tissues. Results: HU increased XO, TNF-α, NF-κB, IL-17, cytochrome C, caspase-3, and 8-OHdG levels in liver tissues. However, both 2 and 4 weeks of NAR supplementation decreased these values, and also NAR supplementation led to an increase in GPx levels in tissues. Conclusions: The results of the study show that increased inflammation, apoptosis, and DNA damage in experimental HU can be prevented by administration of NAR due to inhibition of cytochrome C, NF-κB, caspase-3, and 8-OHdG.

Taurine alleviates endoplasmic reticulum stress, inflammatory cytokine expression and mitochondrial oxidative stress induced by high glucose in the muscle cells of olive flounder (Paralichthysolivaceus)

The aim of the present study was to evaluate the effects of taurine on endoplasmic reticulum stress, inflammatory cytokine expression and mitochondrial oxidative stress induced by high glucose in primary cultured muscle cells of olive flounder (Paralichthys olivaceus). Three experimental groups were designed as follows: muscle cells of olive flounder incubated with three kinds of medium containing 5 mM glucose (control), 33 mM glucose (HG) or 33 mM glucose + 10 mM taurine (HG + T), respectively. Results showed that taurine addition significantly alleviated the decreased activity of superoxide dismutase (SOD) and the ratio of reduced to oxidized glutathione (GSH/GSSG) induced by high glucose. The increase of cellular reactive oxygen species (ROS), malondialdehyde content and cell apoptosis induced by high glucose were alleviated by taurine. Besides, gene expression of glucose-regulated protein 78, PKR-like ER kinase, tumor necrosis factor-α, interleukin-6, interleukin-1β, interleukin-8, muscle atrophy F-box protein and muscle RING-finger protein 1 were significantly up-regulated in the HG group, and taurine addition decreased the expression of these genes. High glucose led to the swelling of the endoplasmic reticulum (ER). Meanwhile, the nuclear translocation of nuclear factor κB (NF-κB) and the release of cytochrome C from mitochondria induced by high glucose were suppressed by taurine addition. These results demonstrated that taurine alleviated ERS, inflammation and mitochondrial oxidative stress induced by high glucose in olive flounder muscle cells. The ROS production, NF-κB signaling pathway and mitochondria function were the main targets of the biological effects of taurine under high glucose condition.

Endoplasmic reticulum stress-dependent activation of TRB3-FoxO1 signaling pathway exacerbates hyperglycemic nephrotoxicity: Protection accorded by Naringenin

Endoplasmic reticulum (ER) dysfunction contributes greatly to the pathophysiology of hyperglycemic nephrotoxicity. This study unravels the critical role of Tribbles 3 (TRB3)-Forkhead box O1 (FoxO1) signaling pathway during hyperglycemic renal toxicity. It also uncovers the novel role of Naringenin, a flavanone, in regulating ER stress in proximal tubular cells, NRK 52E, and kidneys of streptozotocin/nicotinamide induced experimental diabetic Wistar rats. Results demonstrate that expression of ER stress marker proteins including phosphorylated protein kinase ER like kinase (p-PERK), phosphorylated eukaryotic Initiation Factor 2α (p-eIF2α), X Box Binding Protein 1 spliced (XBP1s), Activating Transcription Factor 4 (ATF4) and C/EBP Homologous Protein (CHOP) were upregulated in diabetic kidneys indicating the activation of ER stress response due to nephrotoxicity. Treatment with Naringenin reduced the expression of TRB3, an ER stress-inducible pseudokinase, both in vitro and in vivo. Gene silencing of TRB3 enhanced Akt and FoxO1 phosphorylation and alleviated FoxO1 mediated apoptosis during hyperglycemic nephrotoxicity. Notably, TRB3 gene silencing effects were comparable to the response with Naringenin treatment. Prevention of nuclear colocalization of ATF4 and CHOP in Naringenin treated cells was evident. Naringenin also reduced insulin resistance, apoptosis and glycogen accumulation along with enhancement of glucose tolerance in diabetic rats. Prevention of ultrastructural aberrations in the ER of hyperglycemic renal cells by Naringenin confirmed its anti-ER stress effects. These findings affirm that activation of TRB3-FoxO1 signaling is critical in the pathogenesis of hyperglycemia-induced renal toxicity and protective effect of Naringenin via modulation of ER stress may be exploited as a novel approach for its management.

Naringenin alleviates hyperglycemia-induced renal toxicity by regulating activating transcription factor 4-C/EBP homologous protein mediated apoptosis

Endoplasmic reticulum (ER) dysfunction plays a prominent role in the pathophysiology of diabetic nephropathy (DN). This study aimed to investigate the novel role of Naringenin (a flavanone mainly found in citrus fruits) in modulating ER stress in hyperglycemic NRK 52E cells and STZ/nicotinamide induced diabetes in Wistar rats. The results demonstrated that Naringenin supplementation downregulated the expression of ER stress marker proteins, including p-PERK, p-eIF2α, XBP1s, ATF4 and CHOP during hyperglycemic renal toxicity in vitro and in vivo. Naringenin abrogated hyperglycemia-induced ultrastructural changes in ER, evidencing its anti-ER stress effects. Interestingly, treatment of Naringenin prevented nuclear translocation of ATF4 and CHOP in hyperglycemic renal cells and diabetic kidneys. Naringenin prevented apoptosis in hyperglycemic renal cells and diabetic kidney tissues by downregulating expression of apoptotic marker proteins. Further, photomicrographs of TEM confirmed anti-apoptotic potential of Naringenin as it prevented membrane blebbing and formation of apoptotic bodies in hyperglycemic renal cells. Naringenin improved glucose tolerance, restored serum insulin level and reduced serum glucose level in diabetic rats evidencing its anti-hyperglycemic effects. Histopathological examination of kidney tissues also confirmed prevention of damage after 28 days of Naringenin treatment in diabetic rats. Additionally, Naringenin diminished oxidative stress and improved antioxidant defense response during hyperglycemic renal toxicity. Taken together, our study revealed a novel role of Naringenin in ameliorating ER stress during hyperglycemic renal toxicity along with prevention of apoptosis, cellular and tissue damage. The findings suggest that prevention of ER stress can be exploited as a novel approach for the management of hyperglycemic nephrotoxicity.

The Role of Selected Natural Biomolecules in Sperm Production and Functionality

Emerging evidence from in vivo as well as in vitro studies indicates that natural biomolecules may play important roles in the prevention or management of a wide array of chronic diseases. Furthermore, the use of natural compounds in the treatment of male sub- or infertility has been proposed as a potential alternative to conventional therapeutic options. As such, we aimed to evaluate the effects of selected natural biomolecules on the sperm production, structural integrity, and functional activity. At the same time, we reviewed their possible beneficial or adverse effects on male reproductive health. Using relevant keywords, a literature search was performed to collect currently available information regarding molecular mechanisms by which selected natural biomolecules exhibit their biological effects in the context of male reproductive dysfunction. Evidence gathered from clinical trials, in vitro experiments and in vivo studies suggest that the selected natural compounds affect key targets related to sperm mitochondrial metabolism and motion behavior, oxidative stress, inflammation, DNA integrity and cell death. The majority of reports emphasize on ameliorative, stimulating and protective effects of natural biomolecules on the sperm function. Nevertheless, possible adverse and toxic behavior of natural compounds has been indicated as well, pointing out to a possible dose-dependent impact of natural biomolecules on the sperm survival and functionality. As such, further research leading to a deeper understanding of the beneficial or adverse roles of natural compounds is necessary before these can be employed for the management of male reproductive dysfunction.

Phytochemical and Ethnopharmacological Perspectives of Ehretia laevis

Ehretia laevis Roxb. (Boraginaceae) has been extensively used as a traditional remedy for the treatment of a diverse range of ailments related to the respiratory system, the gastrointestinal tract, the reproductive system, and against several infections. This review critically assesses and documents, for the first time, the fragmented information on E. laevis, including its botanical description, folklore uses, bioactive phyto metabolites and pharmacological activities. The goal is to explore this plant therapeutically. Ethnomedicinal surveys reveal that E. laevis has been used by tribal communities in Asian countries for the treatment of various disorders. Quantitative and qualitative phytochemical investigations of E. laevis showed the presence of important phytoconstituents such as pentacyclic triterpenoids, phenolic acids, flavonoids, fatty acids, steroids, alkaloids, aliphatic alcohols, hydrocarbons, amino acids, carbohydrates, vitamins and minerals. Fresh plant parts, crude extracts, fractions and isolated compounds have been reported to exhibit broad spectrum of therapeutic activities viz., antioxidant, antiarthritic, antidiabetic, anti-inflammatory, antiulcer, antidiarrheal, antidysenteric, wound healing and anti-infective activities. E. laevis is shown to be an excellent potential source of drugs for the mitigation of jaundice, asthma, dysentery, ulcers, diarrhea, ringworm, eczema, diabetes, fissure, syphilis, cuts and wounds, inflammation, liver problems, venereal and infectious disorders. Although few investigations authenticated its traditional uses but employed uncharacterized crude extracts of the plant, the major concerns raised are reproducibility of therapeutic efficacy and safety of plant material. The outcomes of limited pharmacological screening and reported bioactive compounds of E. laevis suggest that there is an urgent need for in-depth pharmacological investigations of the plant.

Quantitative spectrofluorometric assay detecting nuclear condensation and fragmentation in intact cells

At present, nuclear condensation and fragmentation have been estimated also using Hoechst probes in fluorescence microscopy and flow cytometry. However, none of the methods used the Hoechst probes for quantitative spectrofluorometric assessment. Therefore, the aim of the present study was to develop a spectrofluorometric assay for detection of nuclear condensation and fragmentation in the intact cells. We used human hepatoma HepG2 and renal HK-2 cells cultured in 96-well plates treated with potent apoptotic inducers (i.e. cisplatin, staurosporine, camptothecin) for 6-48 h. Afterwards, the cells were incubated with Hoechst 33258 (2 µg/mL) and the increase of fluorescence after binding of the dye to DNA was measured. The developed spectrofluorometric assay was capable to detect nuclear changes caused by all tested apoptotic inducers. Then, we compared the outcomes of the spectrofluorometric assay with other methods detecting cell impairment and apoptosis (i.e. WST-1 and glutathione tests, TUNEL, DNA ladder, caspase activity, PARP-1 and JNKs expressions). We found that our developed spectrofluorometric assay provided results of the same sensitivity as the TUNEL assay but with the advantages of being fast processing, low-cost and a high throughput. Because nuclear condensation and fragmentation can be typical markers of cell death, especially in apoptosis, we suppose that the spectrofluorometric assay could become a routinely used method for characterizing cell death processes.

Quercitrin Attenuates Acetaminophen-Induced Acute Liver Injury by Maintaining Mitochondrial Complex I Activity

The flavonoid quercitrin has a strong antioxidant property. It is also reported to have a protective effect on the liver. However, the mechanism by which it exerts a protective effect on the liver is not fully understood. The objective of this article is to confirm the protective effect of quercitrin extracted from Albiziae flos on acetaminophen (APAP)-induced liver injury and to explain its mechanism. In the in vivo study, quercitrin was administered orally to BALB/c mice at a dose of 50, 100, and 200 mg/kg for seven consecutive days. APAP (300 mg/kg) was injected intraperitoneally after a last dose of quercitrin was administered. Determination of alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), reactive oxygen species (ROS), superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GSH-Px), catalase (CAT), and malondialdehyde (MDA) levels showed that quercitrin effectively attenuated APAP-induced acute liver injury in mice. Results of the in vitro study showed that quercitrin reduced the levels of ROS, protected mitochondria from damage, and restored the activity of mitochondrial complex I in APAP-treated L-02 cells. The addition of rotenone which is an inhibitor of complex I blocked the protective effect of quercitrin. The expression of mitochondrial complex I was also maintained by quercitrin. Our results suggest that quercitrin can maintain the level of mitochondrial complex I in injured cells and restore its activity, which reduces the production of ROS, protects the mitochondria from oxidative stress, and has a protective effect on the liver.

Hesperidin and Naringin Improve Broiler Meat Fatty Acid Profile and Modulate the Expression of Genes Involved in Fatty Acid β-oxidation and Antioxidant Defense in a Dose Dependent Manner

The beneficial properties of the flavanones hesperidin and naringin as feed additives in poultry have lately been under investigation. In broilers, both flavanones have been shown to exhibit antioxidant properties while their individual effects on fatty acid (FA) composition and the underlying molecular mechanisms of their activity have not been explored. Here, we studied their effects on broiler meats' FA profiles and on the expression of genes related to lipid metabolism, antioxidant defense and anti-inflammatory function. The experimental design comprised six treatment groups of broilers, each supplemented from day 11 until slaughter at 42 days with hesperidin, naringin or vitamin E, as follows: the E1 group received 0.75 g of hesperidin per kg of feed, E2 received 1.5 g hesperidin/kg feed, N1 received 0.75 g naringin/kg feed, N2 received 1.5 g naringin/kg feed, vitamin E (VE) received 0.2 g a-tocopheryl acetate/kg feed, and the control group was not provided with a supplemented feed. The VE treatment group served as a positive control for antioxidant activity. An analysis of the FA profiles of the abdominal adipose tissue (fat pad), major pectoralis (breast) and biceps femoris (thigh) muscles showed that both hesperidin and naringin had significant effects on saturated FA (SFA), polyunsaturated FA (PUFA) and omega n-6 content. Both compounds reduced SFA and increased PUFA and n-6 content, as well as reducing the atherogenicity and thrombogenicity indices in the breast muscle and fat pad. The effects on the thigh muscle were limited. An analysis of gene expression in the liver revealed that naringin significantly increased peroxisome proliferator-activated receptor alpha (PPARα), Acyl-CoA oxidase 1 (ACOX1) and glutathione disulfide reductase (GSR) expression. In the breast muscle, both hesperidin and naringin increased fatty acid synthase (FASN) expression and hesperidin increased the expression of adiponectin. In brief, both hesperidin and naringin supplementation beneficially affected FA profiles in the breast meat and fat pad of broiler chicken. These effects could be attributed to an increase in FA β-oxidation since the increased expression of related genes (PPARα and ACOX1) was observed in the liver. Furthermore, the antioxidant activity of hesperidin and naringin previously observed in the meat of broilers could be attributed, at least partly, to the regulation of antioxidant defense genes, as evidenced by the increased GSR expression in response to naringin supplementation.

Design, Synthesis, and Activity Evaluation of Novel Acyclic Nucleosides as Potential Anticancer Agents In Vitro and In Vivo

In the present work, 103 novel acyclic nucleosides were designed, synthesized, and evaluated for their anticancer activities in vitro and in vivo. The structure-activity relationship (SAR) studies revealed that most target compounds inhibited the growth of colon cancer cells in vitro, of which 3-(6-chloro-9H-purin-9-yl)dodecan-1-ol (9b) exhibited the most potent effect against the HCT-116 and SW480 cells with IC50 values of 0.89 and 1.15 μM, respectively. Furthermore, all of the (R)-configured acyclic nucleoside derivatives displayed more potent anticancer activity compared to their (S)-counterparts. Mechanistic studies revealed that compound 9b triggered apoptosis in the cancer cell lines via depolarization of the mitochondrial membrane and effectively inhibited colony formation. Importantly, compound 9b inhibited the growth of the SW480 xenograft in a mouse model with low systemic toxicity. These results indicated that acyclic nucleoside compounds are viable as potent and effective anticancer agents, and compound 9b may serve as a promising lead compound that merits further attention in future anticancer drug discovery.

Potentials of Musa Species Fruits against Oxidative Stress-Induced and Diet-Linked Chronic Diseases: In Vitro and In Vivo Implications of Micronutritional Factors and Dietary Secondary Metabolite Compounds

Nutritional quality and the well-being of the body system are directly linked aspects of human survival. From the unborn foetus to adulthood, the need for sustainable access to micronutrient-rich foods is pertinent and the global consumption of banana and plantain fruits, in effect, contributes to the alleviation of the scourge of malnutrition. This review is particularly aimed at evaluating the pharmacological dimensions through the biological mechanisms of Musa fruits in the body, which represent correlations with their constituent micronutrient factors and dietary polyphenolic constituents such as minerals, vitamin members, anthocyanins, lutein, α-,β- carotenes, neoxanthins and cryptoxanthins, epi- and gallo catechins, catecholamines, 3-carboxycoumarin, β-sitosterol, monoterpenoids, with series of analytical approaches for the various identified compounds being highlighted therein. Derivative value-products from the compartments (flesh and peel) of Musa fruits are equally highlighted, bringing forth the biomedicinal and nutritional relevance, including the potentials of Musa species in dietary diversification approaches.

Effect of crocin and naringenin supplementation in cryopreservation medium on post-thaw rooster sperm quality and expression of apoptosis associated genes

The aim of our study was to examine the effects of crocin (0.5 (C0.5), 1 (C1) and 1.5 (C1.5) mM) and naringenin (50 (N50), 100 (N100) and 150 (N150) μM) in cryopreservation extender for freezing rooster semen. Sperm motility, viability, abnormalities, membrane functionality, active mitochondria, apoptosis status, lipid peroxidation (LP), GPX, SOD, TAC, the mRNA expression of pro-apoptotic (CASPASE 3) and anti-apoptotic (Bcl-2) genes, fertile eggs, hatched eggs and hatching rate were investigated following freeze-thawing. C1 and N100 resulted in higher (P < 0.05) total motility and progressive motility in comparison to the control group. The C1 and N100 groups improved viability, membrane functionality and reduced lipid peroxidation. We found higher values for active mitochondria with C1 and N100 compared to control group. The C1 and N100 groups showed lower percentages of early apoptosis when compared with control group. Also, C1 and N100 had higher TAC, compared to the control group. The mRNA expressions of BCL-2 in the C1 and N100 groups were significantly higher than that of other treatments. The expression of CASPASES 3 was significantly reduced in C1 and N100 group (P < 0.05) when compared to control group. Significantly higher percentages of fertile eggs, hatched eggs and hatching rate were observed in C1 and N100 compared to the control group. In conclusion, crocin at 1 mM and naringenin at 100 μM seem to improve the post-thawing rooster semen quality, fertility and could protect the sperm by reducing the pro-apoptotic (CASPASE 3) and increasing anti-apoptotic (Bcl-2) genes.

By reducing oxidative stress, naringenin mitigates hyperglycaemia-induced upregulation of hepatic nuclear factor erythroid 2-related factor 2 protein

OBJECTIVES

Antioxidant and anti-inflammatory properties of naringenin could confer hepatoprotective effects.

METHODS

Chang cells in culture media were maintained at 37°C and treated with increased concentrations of glucose (5.5-50 mm) and/or naringenin (25-100 µm), respectively, for 24 h. The cells were harvested and carbonyl proteins, antioxidant enzymes and proteins measured in cell lysates. Sprague Dawley rats were divided into 5 groups (n = 7) and orally treated daily for 56 days with 3.0 ml/kg per body weight (BW) distilled water (group 1), 60 mg/kg BW of naringenin (groups 2 and 4), respectively. Groups 3, 4 and 5 were given single 60 mg/kg per BW intraperitoneal injections of streptozotocin or insulin (2.0 IU/kg BW bid), (group 5 only).

KEY FINDINGS

Cell viability was significantly decreased in response to increased hyperglycaemia but naringenin dose-dependently, significantly reversed this compared to controls, respectively. However, antioxidant enzyme activities were reduced due to increased and reduced oxidative stress, respectively. Naringenin further significantly reduced hepatic oxidative stress and nuclear factor erythroid 2-related factor 2 (Nrf2) protein expression and liver : body weight ratios in diabetic compared to controls rats.

CONCLUSIONS

Naringenin confers hepatoprotective antioxidant effects by initially preventing upregulation of Nrf2 protein expression and its downstream antioxidant enzymes.

Genome-Protecting Compounds as Potential Geroprotectors

Throughout life, organisms are exposed to various exogenous and endogenous factors that cause DNA damages and somatic mutations provoking genomic instability. At a young age, compensatory mechanisms of genome protection are activated to prevent phenotypic and functional changes. However, the increasing stress and age-related deterioration in the functioning of these mechanisms result in damage accumulation, overcoming the functional threshold. This leads to aging and the development of age-related diseases. There are several ways to counteract these changes: 1) prevention of DNA damage through stimulation of antioxidant and detoxification systems, as well as transition metal chelation; 2) regulation of DNA methylation, chromatin structure, non-coding RNA activity and prevention of nuclear architecture alterations; 3) improving DNA damage response and repair; 4) selective removal of damaged non-functional and senescent cells. In the article, we have reviewed data about the effects of various trace elements, vitamins, polyphenols, terpenes, and other phytochemicals, as well as a number of synthetic pharmacological substances in these ways. Most of the compounds demonstrate the geroprotective potential and increase the lifespan in model organisms. However, their genome-protecting effects are non-selective and often are conditioned by hormesis. Consequently, the development of selective drugs targeting genome protection is an advanced direction.

Flavonoids modulate tight junction barrier functions in hyperglycemic human intestinal Caco-2 cells

OBJECTIVES

Diabetes mellitus is a chronic disease requiring lifelong medical attention. With hundreds of millions suffering worldwide and a rapidly rising incidence, diabetes mellitus poses a great burden on health care systems. Recent studies investigating the underlying mechanisms involved in disease development in diabetes point to the role of the dysregulation of the intestinal barrier. Hyperglycemia-mediated tight junction deformity is known to contribute to leaky gut in various metabolic disorders. The present study aimed to investigate the role of oxidative stress on intestinal epithelial tight junction (TJ) barrier functions in hyperglycemia. Because many flavonoids are known to influence the cellular redox state, exploring these flavonoids may help to understand the role of TJ barrier in hyperglycemia-mediated oxidative stress, which in turn might unfold the association of oxidative stress and dysfunction of barrier-forming TJs.

METHODS

Caco-2 cells were stimulated with high glucose (HG), with or without flavonoids (quercetin, morin, naringenin), for 24 h. We determined cellular viability, levels of reactive oxygen species, and mitochondrial membrane potential in flavonoids treated HG-Caco-2 cells. The levels of the proinflammatory cytokines, glucose uptake, and expression of glucose transporters were determined on flavonoids treatment. We investigated the effect of flavonoids on TJs functions by measuring transepithelial electrical resistance (a TJ integrity marker), membrane permeability using tracer compounds, and the expressions levels of TJs related molecules on hyperglycemic Caco-2 cell monolayers.

RESULTS

We found that high glucose treatment resulted in reduced cell viability, increased reactive oxygen species production, measurable mitochondrial dysfunction, and decreased transepithelial electrical resistance, with increased membrane permeability. Treatment with the test flavonoids produced increased cell viability and reduced glucose uptake of HG-Caco-2 cells. A concomitant decrease in reactive oxygen species production, proinflammatory cytokines, and Glut-associated genes and proteins were identified with flavonoid treatment. Flavonoids prevented derangement of TJs protein interaction and stabilized membrane permeability.

CONCLUSIONS

These findings indicate that flavonoids confer protection against hyperglycemia-mediated oxidative stress and enhance intestinal barrier functions by modulating underlying intracellular molecular mechanisms.

Naringenin Suppresses Chemically Induced Skin Cancer in Two-Stage Skin Carcinogenesis Mouse Model

Background: Naringenin, a flavonoid present in citrus fruits has many health promoting activities. It has been reported to protect skin from UV radiation, thermal damage and atopic allergies. Despite many skin protective effects, in vivo effect of naringenin on skin cancer has not been reported so far.Objective: The present work was designed to study the chemo preventive effect of naringenin on chemically induced skin cancer in mice.Methods: Two stage model of skin papillomagenesis, using DMBA plus croton oil, was used to study the effect of naringenin in Swiss albino mice. The chemo preventive effect was evaluated using morphological, histopathological and biochemical features.Results: Oral administration of naringenin reduced the skin papilloma in both pre-treatment as well as post-treatment groups of mice. The number as well as size of papilloma was significantly reduced in the treated groups. Histopathological studies showed that naringenin treatment suppressed papillomagenesis. Biochemical studies further revealed decrease in the activity of glyoxalase-1 enzyme and an increase in carbonyl content. The effect was more pronounced in ant-initiation group.Conclusion: Naringenin exhibited anti-tumor effect in two stage carcinogenesis mouse skin tumor model. This study revealed that consumption of citrus fruits and the naringenin therein may be helpful in suppression of skin cancer.

The neuroprotective mechanism of 2-arachidonoylglycerol 2-AG against non-caspase-dependent apoptosis in mice hippocampal neurons following MCAO

OBJECTIVE

In this study, the neuroprotective mechanism of 2-arachidonoylglycerol 2-AG against non-caspase-dependent apoptosis in mice hippocampal neurons following MCAO was investigated.

METHOD

One hundred and fifty healthy clean male C57BL/6 mice were randomly divided into 3 groups: sham group, model group and 2-AG treatment group, 50 mice in each group. A modified Zea Longa method was used to establish a model of middle cerebral artery occlusion (MCAO) in mice. The apoptosis rate and mitochondrial membrane potential of hippocampal nerve cells were measured by flow cytometry. The mRNA expressions of AIF, Endo G and BNIP3 in hippocampal tissues were determined by qPCR. Western blot was used to determine the protein expressions of AIF, Endo G and BNIP3 in the mitochondria of hippocampal tissue.

RESULTS

The apoptosis rate of hippocampal neurons in the group treated with 2-AG was significantly lower than that of the model (P<0.01), which indicated that 2-AG could inhibit the apoptosis of hippocampal neurons induced by MCAO. However, the mitochondrial membrane potential of hippocampal neurons in the group treated with 2-AG was significantly higher than that of the model (P<0.01), indicating that 2-AG could improve the mitochondrial membrane potential of hippocampal neurons in MCAO mice. Real-time quantitative PCR (qPCR) showed that 2-AG could inhibit the gene expressions of AIF, Endo G and BNIP3 in hippocampal tissues. Western blot results showed that 2-AG could inhibit the secretions of AIF, Endo G and BNIP3 into cytoplasm in mitochondria.

CONCLUSION

Endocannabinoids 2-AG had a protective effect on neurons injury, and the mechanism was possibly associated with the protection of the brain nerve cells in the hippocampus and the integrity of the mitochondrial function. Endocannabinoids 2-AG may inhibit the non-caspase-dependent apoptosis pathway, so as to exert its nerve protective effect.

Flavonoids in Cancer and Apoptosis

Cancer is the second leading cause of death globally. Although, there are many different approaches to cancer treatment, they are often painful due to adverse side effects and are sometimes ineffective due to increasing resistance to classical anti-cancer drugs or radiation therapy. Targeting delayed/inhibited apoptosis is a major approach in cancer treatment and a highly active area of research. Plant derived natural compounds are of major interest due to their high bioavailability, safety, minimal side effects and, most importantly, cost effectiveness. Flavonoids have gained importance as anti-cancer agents and have shown great potential as cytotoxic anti-cancer agents promoting apoptosis in cancer cells. In this review, a summary of flavonoids and their effectiveness in cancer treatment targeting apoptosis has been discussed.

New Platinum(II) agent induces bimodal death of apoptosis and autophagy against A549 cancer cell

Agents with multiple modes of tumor cell death can be effective chemotherapeutic drugs. One example of a bimodal chemotherapeutic approach is an agent that can induce both apoptosis and autophagic death. Thus far, no clinical anticancer drug has been shown to simultaneously induce both these pathways. Mono-functional platinum complexes are potent anticancer drug candidates which act through mechanisms distinct from cisplatin. Here, we describe the synthesis and characterize of two mono-functional platinum complexes containing 8-substituted quinoline derivatives as ligands. In comparison to cisplatin, n-Mon-Pt-1 exhibited a greater in vitro cytotoxicity, was more effective in resistant cells and elicited a better anticancer effect. Mechanistic experiments indicate that n-Mon-Pt-1 mainly accumulates in mitochondria, and stimulates significant TrxR inhibition, ROS release and an ER stress response, ultimately resulting in a simultaneous induction of apoptosis and autophagy. Importantly, compared to cisplatin, n-Mon-Pt-1 exhibits lower acute toxicity and better anticancer activity in a murine tumor model.

Mitochondria-targeted platinum(II) complexes induce apoptosis-dependent autophagic cell death mediated by ER-stress in A549 cancer cells

Agents with multiple modes of tumor cell death can be effective chemotherapeutic drugs. One example of a bimodal chemotherapeutic approach is an agent that can induce both apoptosis and autophagic death. Thus far, no clinical anticancer drug has been shown to simultaneously induce both these pathways. Mono-functional platinum complexes are potent anticancer drug candidates which act through mechanisms distinct from cisplatin. Here, we describe the synthesis and characterize of two mono-functional platinum complexes containing 8-substituted quinoline derivatives as ligands, [PtL₁Cl]Cl [L₁ = (Z)-1-(pyridin-2-yl)-N-(quinolin-8-ylmethylene) methanamine] (Mon-Pt-1) and [PtL₂Cl]Cl [L₂ = (Z)-2-(pyridin-2-yl)-N-(quinolin-8-ylmethylene) ethanamine] (Mon-Pt-2). In comparison to cisplatin, Mon-Pt-2 exhibited a greater in vitro cytotoxicity, was more effective in resistant cells and elicited a better anticancer effect. Mechanistic experiments indicate that Mon-Pt-2 mainly accumulates in mitochondria, and stimulates significant TrxR inhibition ROS release and an ER stress response, mediated by mitochondrial dysfunction, ultimately resulting in a simultaneous induction of apoptosis and autophagy. Importantly, compared to cisplatin, Mon-Pt-2 exhibits lower acute toxicity and better anticancer activity in a murine tumor model. To the best of our knowledge, Mon-Pt-2 is the first mono-functional platinum complex inducing pro-death autophagy and apoptosis of cancer cells.

Downregulation of microRNA‑34a inhibits oxidized low‑density lipoprotein‑induced apoptosis and oxidative stress in human umbilical vein endothelial cells

Oxidized low‑density lipoprotein (ox‑LDL) promotes endothelial cell dysfunction, which is a primary risk factor for the development of atherosclerosis. A previous study reported that microRNA (miRNA/miR)‑34a is upregulated in atherosclerotic samples. However, its function and underlying mechanisms remain to be fully elucidated. In the present study, miRNA microarray analysis was performed to investigate the miRNA expression profile in atherosclerotic plaque tissues and examine the role of miR‑34a in ox‑LDL‑induced apoptosis of human umbilical vein endothelial cells (HUVECs). Cell viability, apoptosis and protein expression was determined by a cell counting kit‑8 assay, flow cytometry and western blot analysis, respectively. It was observed that miR‑34a was upregulated in atherosclerotic plaque tissues and that ox‑LDL treatment significantly increased the levels of miR‑34a in a dose‑dependent manner in the HUVECs. The knockdown of miR‑34a increased the protein expression of B‑cell lymphoma 2 (Bcl‑2) and cell viability, improved mitochondrial membrane potential, and decreased the activity of caspase‑3, number of apoptotic cells and release of cytochrome c from mitochondria in the ox‑LDL‑treated HUVECs. The results also demonstrated that the knockdown of miR‑34a suppressed the levels of ox‑LDL‑induced reactive oxygen species (ROS) in HUVECs. Additionally, it was found that Bcl‑2 was a target of miR‑34a in HUVECs, and that silencing Bcl‑2 abrogated the protective effects of the downregulation of miR‑34a on ox‑LDL‑induced apoptosis. These data indicated that the knockdown of miR‑34a protected against ox‑LDL apoptosis and ROS in HUVECs via inhibiting the mitochondrial apoptotic pathway, suggesting it may offer potential as a biomarker in the clinical diagnosis and as a target for the treatment of atherosclerosis.

Organometallic Gold(III) Complexes Similar to Tetrahydroisoquinoline Induce ER-Stress-Mediated Apoptosis and Pro-Death Autophagy in A549 Cancer Cells

Agents inducing both apoptosis and autophagic death can be effective chemotherapeutic drugs. In our present work, we synthesized two organometallic gold(III) complexes harboring C^N ligands that structurally resemble tetrahydroisoquinoline (THIQ): Cyc-Au-1 (AuL¹Cl₂, L¹ = 3,4-dimethoxyphenethylamine) and Cyc-Au-2 (AuL²Cl₂, L² = methylenedioxyphenethylamine). In screening their in vitro activity, we found both gold complexes exhibited lower toxicity, lower resistance factors, and better anticancer activity than those of cisplatin. The organometallic gold(III) complexes accumulate in mitochondria and induce elevated ROS and an ER stress response through mitochondrial dysfunction. These effects ultimately result in simultaneous apoptosis and autophagy. Importantly, compared to cisplatin, Cyc-Au-2 exhibits lower toxicity and better anticancer activity in a murine tumor model. To the best of our knowledge, Cyc-Au-2 is the first organometallic Au(III) compound that induces apoptosis and autophagic death. On the basis of our results, we believe Cyc-Au-2 to be a promising anticancer agent or lead compound for further anticancer drug development.

d-Fagomine Attenuates High Glucose-Induced Endothelial Cell Oxidative Damage by Upregulating the Expression of PGC-1α

d-Fagomine, an analogue of 1-deoxynojirimycin (DNJ), has been shown to have hypoglycemic activity. This study is aimed at investigating if d-fagomine could attenuate high glucose-induced oxidative stress in human umbilical vein endothelial cells (HUVECs) and elucidate the underlying mechanism. Our results showed that d-fagomine reduced intracellular reactive oxygen species (ROS) production and malondialdehyde (MDA) levels. It also reversed the decrease of superoxide dismutases (SOD) and glutathione reductase (GR) activity, suggesting an inhibitory effect of d-fagomine on oxidative damage in HUVECs. d-Fagomine restored the loss of mitochondrial membrane potential, implying its protective role on mitochondrial function. In addition, d-fagomine activated the AMPK signaling pathway through LKB1, increased the expression of SIRT1 and PGC-1α, and attenuated the inhibitory effect on SIRT1 and PGC-1α activity caused by AMPK and SIRT1 inhibitor. d-Fagomine attenuated high glucose-induced oxidative stress in HUVECs through the AMPK/SIRT1/PGC-1α pathway.

BH3-only protein BIM: An emerging target in chemotherapy

BH3-only proteins constitute major proportion of pro-apoptotic members of B-cell lymphoma 2 (Bcl-2) family of apoptotic regulatory proteins and participate in embryonic development, tissue homeostasis and immunity. Absence of BH3-only proteins contributes to autoimmune disorders and tumorigenesis. Bim (Bcl-2 Interacting Mediator of cell death), most important member of BH3-only proteins, shares a BH3-only domain (9-16 aa) among 4 domains (BH1-BH4) of Bcl-2 family proteins and highly pro-apoptotic in nature. Bim initiates the intrinsic apoptotic pathway under both physiological and patho-physiological conditions. Reduction in Bim expression was found to be associated with tumor promotion and autoimmunity, while overexpression inhibited tumor growth and drug resistance as cancer cells suppress Bim expression and stability. Apart from its role in normal homeostasis, Bim has emerged as a central player in regulation of tumorigenesis, therefore gaining attention as a plausible target for chemotherapy. Regulation of Bim expression and stability is complicated and regulated at multiple levels viz. transcriptional, post-transcriptional, post-translational (preferably by phosphorylation and ubiquitination), epigenetic (by promoter acetylation or methylation) including miRNAs. Furthermore, control over Bim expression and stability may be exploited to enhance chemotherapeutic efficacy, overcome drug resistance and select anticancer drug regimen as various chemotherapeutic agents exploit Bim as an executioner of cell death. Owing to its potent anti-tumorigenic activity many BH3 mimetics e.g. ABT-737, ABT-263, obatoclax, AT-101and A-1210477 have been developed and entered in clinical trials. It is more likely that in near future strategies commanding Bim expression and stability ultimately lead to Bim based therapeutic regimen for cancer treatment.

Naringenin protects keratinocytes from oxidative stress injury via inhibition of the NOD2-mediated NF-κB pathway in pemphigus vulgaris

Naringenin is known to have anti-oxidative activity; however, the effect of naringenin on the progression of pemphigus vulgaris (PV) still remains unclear. This study aims to analyze the effect of naringenin on HaCaT cell apoptosis and oxidative damage under the treatment of PV serum. The results showed that PV serum significantly induced cell apoptosis compared with the control group; whereas, comparing with PV group, naringenin inhibited cell apoptosis. Moreover, PV serum increased the expression of bax and caspase-3, and decreased the expression of bcl-2; but naringenin significantly suppressed the expression of bax and caspase-3, induced the expression of bcl-2. Naringenin inhibited PV serum-induced disruption of cell-cell contacts. Naringenin also down-regulated the expression of Dsg1, Dsg3 and E-cadherin compared with the PV group. Additionally, naringenin noticeably decreased the PV serum-induced ROS production and alleviated PV serum induced the drop of mitochondrial membrane potential. Furthermore, naringenin increased the activity of SOD, GSH-Px and TAC under the treatment of PV serum. Naringenin also decreased the expression of NOD2, RIPK2 and NF-κB p-p65, but this effect could be reversed by muramyl dipeptide (MDP). In conclusion, these results suggested that naringenin protected keratinocytes from apoptosis and oxidative stress injury through inhibition of the NOD2-mediated NF-κB pathway.

CCND1-BCL2 Gene Network: A direct target of Amifostine in human acute megakaryocytic leukemia cells

Amifostine, 2-(3-aminopropyl) aminoethyl phosphorothioate, is a broad-spectrum cytoprotective agent used to treat nuclear radiation and chemical weapon injuries. Recently, amifostine has been shown to have a profound biological influence on tumor cells. To examine the effects and mechanisms underlying the effects of amifostine on human acute megakaryocytic leukemia, we evaluated the efficacy of amifostine against Dami cells and observed a cell cycle arrest in G₂ /M phase. Amifostine treatment also induced cell apoptosis of Dami cells which corresponds to formal studies. Through whole-genome microarray and bioinformatics analyses, we found that amifostine affected the gene expression of CCND1, BCL2, and CASP3 which revealed the mechanism amifostine acted on Dami cells. Thus, CCND1-BCL2 Gene Network is predicted to be a direct target of amifostine treating human acute megakaryocytic leukemia, which may provide a novel potential target for the therapy of several subtypes of human AML.

Bisdemethoxycurcumin-induced S phase arrest through the inhibition of cyclin A and E and induction of apoptosis via endoplasmic reticulum stress and mitochondria-dependent pathways in human lung cancer NCI H460 cells

Curcuminoids are the major natural phenolic compounds found in the rhizome of many Curcuma species. Curcuminoids consist of a mixture of curcumin, demethoxycurcumin (DMC), and bisdemethoxycurcumin (BDMC). Although numerous studies have shown that curcumin induced cell apoptosis in many human cancer cells, however, mechanisms of BDMC-inhibited cell growth and -induced apoptosis in human lung cancer cells still remain unclear. Herein, we investigated the effect of BDMC on the cell death via the cell cycle arrest and induction of apoptosis in NCI H460 human lung cancer cells. Flow cytometry assay was used to measure viable cells, cell cycle distribution, the productions of reactive oxygen species (ROS) and Ca²⁺ , mitochondrial membrane potential (ΔΨ_m ) and caspase-3, -8 and -9 activity. DNA damage and condension were assayed by Comet assay and DAPI staining, respectively. Western blotting was used to measure the changes of cell cycle and apoptosis associated protein expressions. Results indicated that BDMC significantly induced cell death through induced S phase arrest and induced apoptosis. Moreover, DMC induced DNA damage and condension, increased ROS and Ca²⁺ productions and decreased the levels of ΔΨ_m and promoted activities caspase-3, -8, and -9. Western blotting results showed that BDMC inhibited Cdc25A, cyclin A and E for causing S phase arrest, furthermore, promoted the expression of AIF, Endo G and PARP and the levels of Fas ligand (Fas L) and Fas were also up-regulated. Results also indicated that BDMC increased ER stress associated protein expression such as GRP78, GADD153, IRE1α, IRE1β, ATF-6α, ATF-6β, and caspase-4. Taken together, we suggest that BDMC induced cell apoptosis through multiple signal pathways such as extrinsic, intrinsic and ES tress pathway. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1899-1908, 2016.

Naringenin protects against isoniazid- and rifampicin-induced apoptosis in hepatic injury

AIM

To explore the protective effects and mechanisms of naringenin (NRG) on hepatic injury induced by isoniazid (INH) and rifampicin (RIF).

METHODS

Male mice were randomly divided into four groups and treated for 14 d as follows: normal control group was administered intragastrically with normal saline solution alone; model group was administered intragastrically with INH (100 mg/kg) and RIF (100 mg/kg); low- and high-dosage NRG pretreatment groups were administered intragastrically with different doses of NRG (50 or 100 mg/kg) 2 h before INH and RIF challenge. Mice were killed 16 h after the last dose of drug treatment to determine activity of serum transaminases. Oxidative stress was evaluated by measuring hepatic glutathione (GSH) and superoxide dismutase (SOD) and malondialdehyde (MDA) levels. Histopathological changes in hepatic tissue were observed under the optical microscope. Hepatocyte apoptosis was measured by TUNEL assay and caspase-3 activation. Expression of Bcl-2 and Bax in liver was determined by western blot.

RESULTS

Both low- and high-dosage NRG pretreatment obviously alleviated serum levels of alanine aminotransferase and aspartate aminotransferase, liver index, hepatic MDA content, and increased hepatic GSH content and SOD activity compared with the INH and RIF-treated group (44.71 ± 8.15 U/L, 38.22 ± 6.64 U/L vs 58.15 ± 10.54 U/L; 98.36 ± 14.78 U/L, 92.41 ± 13.59 U/L vs 133.05 ± 19.36 U/L; 5.34% ± 0.26%, 4.93% ± 0.25% vs 5.71% ± 0.28%; 2.76 ± 0.67 nmol/mgprot, 2.64 ± 0.64 nmol/mgprot vs 4.49 ± 1.12 nmol/mgprot; 5.91 ± 1.31 mg/gprot, 6.42 ± 1.42 mg/gprot vs 3.11 ± 0.73 mg/gprot; 137.31 ± 24.62 U/mgprot, 148.83 ± 26.75 U/mgprot vs 102.34 ± 19.22 U/mgprot; all P < 0.01 or 0.05). Histopathological evaluation showed obvious necrosis and inflammatory cell infiltration in liver of mice administered INH and RIF; however, mice pretreated with NRG showed minor hepatic injury. In addition, INH and RIF resulted in hepatocyte apoptosis, and NRG pretreatment dramatically suppressed INH- and RIF-induced hepatocytes apoptosis. Furthermore, NRG-mediated anti-apoptotic effects seemed to be in connection with its regulation of Bax and Bcl-2 protein expression in hepatic tissue.

CONCLUSION

NRG might attenuate INH- and RIF-induced hepatic injury via suppression of oxidative stress and hepatocyte apoptosis.

Naringenin ameliorates hypoxia/reoxygenation-induced endoplasmic reticulum stress-mediated apoptosis in H9c2 myocardial cells: involvement in ATF6, IRE1α and PERK signaling activation

Naringenin, a flavanone mainly derived from grapes and citrus fruits, has been reported to exhibit cardioprotective effects. Accumulating evidence has confirmed that endoplasmic reticulum (ER) stress-mediated apoptosis participates in the process of myocardial ischemia/reperfusion injury and inhibiting ER stress is a potential therapeutic target/strategy in preventing cardiovascular diseases. Herein, the current study was designed to investigate whether naringenin protects H9c2 myocardial cells against hypoxia/reoxygenation (H/R) injury via attenuating ER stress or ER stress-mediated apoptosis. Our results showed that naringenin treatment resulted in obvious increases in the viability of H9c2 cells and the expression of Bcl-2 (anti-apoptotic protein), and decreases in the morphological changes of apoptotic cells, the activity of caspase-3 and the expression of Bax (pro-apoptotic protein) in H/R-treated H9c2 cells, implying the protective effects of naringenin against H/R-induced injury. In addition, naringenin also significantly reversed H/R-induced ER stress as evidenced by the up-regulation of Glucose-regulated protein 78, C/EBP homologous protein and Cleaved caspase-12 proteins. Meanwhile, naringenin remarkably reversed H/R-induced the increases in the expression of cleaved activating transcription factor 6 (ATF6) and phosphorylation levels of phospho-extracellular regulated protein kinases (PERK) and inositol-requiring enzyme-1α (IRE1α) in H9c2 cells. Finally, we found that ATF6 siRNA, PERK siRNA or IRE1α siRNA abolished H/R-induced cytotoxicity and apoptosis in H9c2 cells. In conclusion, these results confirmed that ER stress-mediated apoptosis contributes to the protection effects of naringenin against H/R injury, which is potentially involved in ATF6, IRE1α and PERK signaling activation.

Crude extract of Rheum palmatum L. Induces cell cycle arrest S phase and apoptosis through mitochondrial-dependent pathways in U-2 OS human osteosarcoma cells

Cancer is the second cause of death in children. Osteosarcoma is the most common primary malignancy of solid bone cancer primarily affecting adolescents and young adults. In the Chinese population, the crude extract of Rheum palmatum L. (CERP) has been used for treating different diseases, including SARS, rheumatoid arthritis, coxsackievirus B3, and human colon cancer cell, pancreatic cancer. There are no reports on CERP and human osteosarcoma cells. The present study examined effects of CERP on cytotoxicity including cell cycle distribution and cell death (apoptosis) in U-2 OS human osteosarcoma cells. CERP significantly induced S phase arrest in U-2 OS cells in a dose-dependent. CERP produced DNA damage and DNA condensation. Other effects of CERP were stimulation of ROS and Ca(2+) , mitochondria impairment, and activation of caspase-3, -8, and -9. CERP increased the levels of Bax, Bak, Bad, cyclin B, Fas, PARP, GRP78, GADD153, AIF, Endo G, Calpain-2, p21, and p27, but decreased the levels of Bcl-2, BCL-X, XIAP, Akt, CDC25A, CDK2, Cyclin A, and Cyclin E of U-2 OS cells. It was also observed that CERP promoted the expression of AIF, Endo G, GADD153, and cytochrome c. These results indicate that CERP has anticancer effects in vitro and provide the foundation for in vivo studies of animal models of osteosarcoma. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 957-969, 2016.

Biochemical and Molecular Mechanisms of Radioprotective Effects of Naringenin, a Phytochemical from Citrus Fruits

The present study was aimed to evaluate the radioprotective effects of naringenin in vivo using Swiss albino mice as a model system. Oral administration of 50 mg/kg body weight of naringenin for 7 days prior to radiation exposure protected mice against radiation-induced DNA, chromosomal and membrane damage. Naringenin pretreatment also increased the antioxidant status of irradiated mice. Multiple factors operating at cellular and molecular levels led to increased endogenous spleen colonies and survival of mice. Although naringenin induces apoptosis in cancer cells we found that it can protect against radiation-induced apoptosis in normal cells by modulating the expression of p53, Bax, and Bcl-2. The results from the present study indicate that naringenin inhibits the NF-kB pathway and down regulates radiation-induced apoptotic proteins resulting in radioprotection at the cellular, tissue and organism levels.

Enhanced anticancer effect of ABT-737 in combination with naringenin on gastric cancer cells

Gastric cancer is the second leading cause of cancer-associated mortality and is a frequently occurring cancer worldwide. Multiple drug resistance of gastric cancer cells leads to the poor prognosis. In addition, overexpression of anti-apoptotic protein B-cell lymphoma (Bcl)-2 have been demonstrated in various cancer cells and is closely associated with drug resistance and poor prognosis. Naringenin is a flavonoid that has antimutagenic and anticarcinogenic activities in numerous cancer types. In the present study, naringenin and a Bcl-2 inhibitor, ABT-737, were used to investigate their combinative anticancer effect in the SGC7901 gastric cancer cell line. The results revealed that naringenin and ABT-737 were able to inhibit SGC7901 cell growth and colony formation, alone or in combination. Furthermore, the combination of these drugs was found to further increase the cleavage of caspase-3 and poly ADP-ribose polymerase. Naringenin and ABT-737 also decreased Akt activation and increased p53 expression, suggesting the involvement of these pathways in the inhibition of gastric cell growth.

Doxorubicin-induced necrosis is mediated by poly-(ADP-ribose) polymerase 1 (PARP1) but is independent of p53

Necrosis, unregulated cell death, is characterized by plasma membrane rupture as well as nuclear and cellular swelling. However, it has recently been reported that necrosis is a regulated form of cell death mediated by poly-(ADP-ribose) polymerase 1 (PARP1). PARP1 is thought to mediate necrosis by inducing DNA damage, although this remains unconfirmed. In this study, we examined the mechanisms of PARP1-mediated necrosis following doxorubicin (DOX)-induced DNA damage in human kidney proximal tubular (HK-2) cells. DOX initiated DNA damage response (DDR) and upregulated PARP1 and p53 expression, resulting in morphological changes similar to those observed during necrosis. Additionally, DOX induced mitochondrial hyper-activation, as evidenced by increased mitochondrial respiration and cytosolic ATP (cATP) production. However, DOX affected mitochondrial mass. DOX-induced DNA damage, cytosolic reactive oxygen species (cROS) generation, and mitochondrial hyper-activation decreased in cells with inhibited PARP1 expression, while generation of nitric oxide (NO) and mitochondrial ROS (mROS) remained unaffected. Moreover, DOX-induced DNA damage, cell cycle changes, and oxidative stress were not affected by p53 inhibition. These findings suggest that DNA damage induced necrosis through a PARP1-dependent and p53-independent pathway.

Suppression in PHLPP2 induction by morin promotes Nrf2-regulated cellular defenses against oxidative injury to primary rat hepatocytes

Recent advances indicate a possible role of phytochemicals as modulatory factors in signaling pathways. We have previously demonstrated PHLPP2-mediated suppression of Nrf2 responses during oxidant attack. The present study was designed to explore Nrf2-potentiating mechanism of morin, a flavonol, via its possible role in intervening PHLPP2-regulated Akt/GSK3β/Fyn kinase axis. Efficacy of morin was evaluated against oxidative stress-mediated damage to primary hepatocytes by tert-butyl hydroperoxide (tBHP) and acetaminophen. The anti-cytotoxic effects of morin were found to be a consequence of fortification of Nrf2-regulated antioxidant defenses since morin failed to sustain activities of redox enzyme in Nrf2 silenced hepatocytes. Morin promoted Nrf2 stability and its nuclear retention by possibly modulating PHLPP2 activity which subdues cellular Nrf2 responses by activating Fyn kinase. Pull-down assay using morin-conjugated beads indicated the binding affinity of morin towards PHLPP2. Molecular docking also revealed the propensity of morin to occupy the active site of PHLPP2 enzyme. Thus, dietary phytochemical morin was observed to counteract oxidant-induced hepatocellular damage by promoting Nrf2-regulated transcriptional induction. The findings support the novel role of morin in potentiating Nrf2 responses by limiting PHLPP2 and hence Fyn kinase activation. Therefore, morin may be exploited in developing novel therapeutic strategy aimed at enhancing Nrf2 responses.

•

Cytoprotection against tBHP-evoked oxidative stress by morin is Nrf2-regulated.

•

Morin prevents Nrf2-destabilization via PHLPP2-Akt-GSK3β-Fyn kinase pathway.

•

In silico docking studies confirmed PHLPP2 activity inhibition by morin.

•

Morin mitigates APAP induced cytotoxicity by suppressing PHLPP2 pathway.

Naringenin accords hepatoprotection from streptozotocin induced diabetes in vivo by modulating mitochondrial dysfunction and apoptotic signaling cascade

Diabetic complications cause noticeable liver damage, which finally progresses to diabetic hepatopathy. Nutritive antioxidants not only reduce the liver damage, but also prevent it by modulating the release of various proteins involved in apoptotic signaling cascades. This study explores the molecular mechanisms underlying diabetes-induced liver damage and its modulation by naringenin. Antioxidant status, liver & kidney biomarker enzymes, reactive oxygen species (ROS) generation, mitochondrial membrane potential, expression of apoptotic proteins like Bax (bcl-2 associated X), Bcl-2 (b-cell Lymhoma-2), Caspase-3, Caspase-9, AIF (Apoptosis inducing factor) and Endo-G (Endonuclease-G) were studied in streptozotocin induced diabetic rats. Significant hyperglycemia, disturbed antioxidant status, altered carbohydrate metabolizing enzymes, increased ROS and lipid peroxidation; decreased mitochondrial membrane potential and enhanced release of AIF and Endo-G were observed. Hyperglycemia also affected apoptosis and its related genes at both transcriptional and translational level (Caspase-3 & 9, Bax and Bcl-2) in the liver of diabetic rats. Naringenin, a flavonone, exerted anti-hyperglycemic effect and was able to prevent oxidative stress and resultant apoptotic events caused due to diabetes-induced hepatotoxicity. Thus, our study shows, a protective effect of naringenin against diabetes induced liver damage and redox imbalance, which could further be exploited for the management of diabetic hepatopathy.

Cyanidin-3-O-β-glucoside protects primary mouse hepatocytes against high glucose-induced apoptosis by modulating mitochondrial dysfunction and the PI3K/Akt pathway

Apoptosis is an early event of steatohepatitis in non-alcoholic fatty liver disease (NAFLD), and an increase in oxidative stress induced by hyperglycemia has been linked to an acceleration of apoptosis in hepatocytes. Cyanidin-3-O-β-glucoside (C3G), a classic anthocyanin, has been reported to reduce oxidative stress and attenuate non-alcoholic steatohepatitis in mice. In this study, we evaluated the toxicity of high glucose in primary hepatocytes of mice fed with a high fat diet and amelioration of this toxicity by C3G. Incubation of hepatocytes with 35mM glucose for 12h resulted in a significant decrease in cell viability and increase in apoptotic cell death. Furthermore, hyperglycemia-induced mitochondrial depolarization was accompanied by the release of cytochrome c and altered expression of Bax and Bcl-2, suggesting a mitochondria-mediated apoptotic mode of cell death. Pre-incubation with 50μM C3G induced changes associated with better cell survival and function, including a reduction in reactive species generation, improvement of mitochondrial membrane potential, inactivation of caspase-3 and -9, and down-regulation of the pro-apoptotic Bax protein. We further investigated the role of the phosphatidylinositol 3-kinase (PI3K)/Akt and mitogen-activated protein kinases (MAPKs) pathways with respect to the anti-apoptotic action of C3G, and our results showed that C3G could activate Akt. Additionally, C3G inactivated c-Jun N-terminal protein kinase (JNK), but not extracellular signal-regulated kinase or p38 MAPK, in glucose-stressed cells. Interestingly, JNK inhibitor enhanced the protective effect of C3G on cell survival. Our results suggest that anthocyanin C3G may exhibit hepatoprotective potential against NAFLD by promoting functional integrity and survival of hepatocytes.

Cantharidin induces apoptosis of H460 human lung cancer cells through mitochondria-dependent pathways

Lung cancer is one of the leading causes of death in cancer-related diseases. Cantharidin (CTD) is one of the components of natural mylabris (Mylabris phalerata Pallas). Numerous studies have shown that CTD induced cytotoxic effects on cancer cells. However, there is no report to demonstrate that CTD induced apoptosis in human lung cancer cells. Herein, we investigated the effect of CTD on the cell death via the induction of apoptosis in H460 human lung cancer cells. Flow cytometry assay was used for examining the percentage of cell viability, sub-G1 phase of the cell cycle, reactive oxygen species (ROS) and Ca²⁺ productions and the levels of mitochondrial membrane potential (∆Ψm). Annexin V/PI staining and DNA gel electrophoresis were also used for examining cell apoptosis. Western blot analysis was used to examine the changes of apoptosis associated protein expression and confocal microscopy for examining the translocation apoptosis associated protein. Results indicated that CTD significantly induced cell morphological changes and decreased the percentage of viable H460 cells. CTD induced apoptosis based on the occurrence of sub-G1 phase and DNA fragmentation. We found that CTD increased gene expression (mRNA) of caspase-3 and -8. Moreover, CTD increased ROS and Ca2+ production and decreased the levels of ∆Ψm. Western blot analysis results showed that CTD increased the expression of cleavage caspase-3 and -8, cytochrome c, Bax and AIF but inhibited the levels of Bcl-xL. CTD promoted ER stress associated protein expression such as GRP78, IRE1α, IRE1β, ATF6α and caspase-4 and it also promoted the expression of calpain 2 and XBP-1, but inhibited calpain 1 that is associated with apoptosis pathways. Based on those observations, we suggest that CTD may be used as a novel anticancer agent for the treatment of lung cancer in the future.

O-hexadecyl-dextran entrapped berberine nanoparticles abrogate high glucose stress induced apoptosis in primary rat hepatocytes

Nanotized phytochemicals are being explored by researchers for promoting their uptake and effectiveness at lower concentrations. In this study, O-hexadecyl-dextran entrapped berberine chloride nanoparticles (BC-HDD NPs) were prepared, and evaluated for their cytoprotective efficacy in high glucose stressed primary hepatocytes and the results obtained compared with bulk berberine chloride (BBR) treatment. The nanotized formulation treated primary hepatocytes that were exposed to high glucose (40 mM), showed increased viability compared to the bulk BBR treated cells. BC-HDD NPs reduced the ROS generation by ∼ 3.5 fold during co-treatment, prevented GSH depletion by ∼ 1.6 fold, reduced NO formation by ∼ 5 fold and significantly prevented decline in SOD activity in stressed cells. Lipid peroxidation was also prevented by ∼ 1.9 fold in the presence of these NPs confirming the antioxidant capacity of the formulation. High glucose stress increased Bax/Bcl2 ratio followed by mitochondrial depolarization and activation of caspase-9/-3 confirming involvement of mitochondrial pathway of apoptosis in the exposed cells. Co- and post-treatment of BC-HDD NPs prevented depolarization of mitochondrial membrane, reduced Bax/Bcl2 ratio and prevented externalization of phosphatidyl-serine confirming their anti-apoptotic capacity in those cells. Sub-G1 phase apparent in high glucose stressed cells was not seen in BC-HDD NPs treated cells. The present study reveals that BC-HDD NPs at ∼ 20 fold lower concentration are as effective as BBR in preventing high glucose induced oxidative stress, mitochondrial depolarization and downstream events of apoptotic cell death.