Peroxide-induced Cell Apoptosis Research Articles

Artemisinin Confers Cytoprotection toward Hydrogen Peroxide-Induced Cell Apoptosis in Retinal Pigment Epithelial Cells in Correlation with the Increased Acetylation of Histone H4 at Lysine 8.

Increased oxidative stress is one of the critical pathologies inducing age-related macular degeneration (AMD), characterized by retinal pigment epithelial (RPE) cell damage and death. The unbalanced acetylation and deacetylation of histones have been implicated in AMD pathogenesis or hydrogen peroxide (H2O2)-induced cell damage. Therefore, strategies aimed at controlling the balance between acetylation and deacetylation may effectively protect RPE cells from oxidative damage. Artemisinin is an antimalarial lactone drug derived from Artemisia annua, with antioxidant activity known to modulate histone acetylation in the brain, but its effect on the retina is unknown. In this study, we aimed to investigate whether Artemisinin exerts a cytoprotective effect on oxidative stress-induced apoptosis in RPE cells by regulating histone acetylation. We hypothesized that Artemisinin confers cytoprotection toward H2O2-induced apoptosis in RPE cells through this mechanism. In the present study, we found that Artemisinin at a sub-clinic dosage of 20 μM inhibited the H2O2-induced cell viability decrease and B-cell lymphoma 2 (Bcl-2) protein level decrease and attenuated the H2O2-induced decrease in the histone H4 lysine (Lys) 8 acetylation [Acetyl-H4 (Lys 8)] level in the retinal RPE cell line D407. As expected, histone deacetylase inhibitor Trichostatin A at the concentration of 250 nM increased the Acetyl-H4 (Lys 8) level in D407 cells and attenuated the H2O2-induced cell viability decrease and apoptosis. Similar findings were obtained using adult RPE (ARPE)19 cells, another human RPE cell line, and primary human RPE cell cultures. In conclusion, these results confirmed our hypothesis and indicated that Artemisinin attenuated H2O2-induced apoptosis in apparent correlation with the increase in the Acetyl-H4 (Lys 8) level, which is associated with gene transcription and cell survival. By modulating histone acetylation, Artemisinin may restore the balance between acetylation and deacetylation and enhance the resistance and survival of RPE cells under oxidative stress. Our study provides novel mechanistic insights into the effect of Artemisinin on histone acetylation and apoptosis in RPE cells and supports the potential application of Artemisinin in the prevention and/or treatment of AMD.

Deferasirox protects against hydrogen peroxide-induced cell apoptosis by inhibiting ubiquitination and degradation of p21WAF1/CIP1

Deferasirox (DFX) is an iron chelator approved for the treatment of iron overload diseases. However, the role of DFX in oxidative stress-induced cell apoptosis and the exact molecular mechanisms underlying these processes remain poorly understood and require further investigation. In this study, we found that DFX rendered resistant to H2O2-induced apoptosis in HEK293T cells, reduced the intracellular levels of the labile iron pool (LIP) and oxidative stress induced by H2O2. Furthermore, DFX inhibited the ubiquitination and degradation of the cyclin-dependent kinase inhibitor p21WAF1/CIP1 (p21) via modulation of the interaction of p21 with SCF-Skp2. DFX also showed the inhibition effect on the activation of c-Jun N-terminal kinase (JNK), pro-caspase-3 and related mitochondrial apoptosis pathway induced by H2O2. These results provide novel insights into the molecular mechanism underpinning iron-mediated oxidative stress and apoptosis, and they may represent a promising target for therapeutic interventions in related pathological conditions.

Neuroprotective Potential of Dimethyl Fumarate-loaded Polymeric Nanoparticles against Multiple Sclerosis

The aim of the present study was to access the potential of dimethyl fumarate-loaded chitosan polymeric nanoparticles for the management of multiple sclerosis. Dimethyl fumarate-loaded chitosan nanoparticles were prepared by polyelectrolyte complex coaservation technique. The prepared nanoparticles were characterized and found to have an average particle size of 324 nm, zeta potential of –34.85 mv and a poly dispersity index of 0.367. The entrapment efficiency was found to be 65.36 % and the drug loading was 28 %. The formulation’s in vitro drug release profile and stability parameters were also evaluated. Cumulative percent drug release was found to be 84 % up to 24 hours and the formulation was found to be stable at 28° for 90 days. In vitro neuroprotective effect of the nanoformulation was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on human neuroblast SH-SY5Y cells and the treated cells showed improved cell viability under hydrogen peroxide-induced cell apoptosis. In vivo cuprizone model for multiple sclerosis in rodents also confirmed these findings by showing a significant increase in locomotion score.

Rg1 protects rat bone marrow stem cells against hydrogen peroxide-induced cell apoptosis through the PI3K/Akt pathway.

The aim of the present study was to investigate the protective mechanism of ginsenosideRg1 against the apoptosis of rat bone marrow stem cells (rBMSCs) under oxidative stress, and to determine the association with the phosphoinositide 3-kinase (PI3K)/protein kinaseB (Akt) pathway. H2O2 was used to induce oxidative injury in rBMSCs. The cells in the H2O2 model group were treated with 800µM H2O2 for 6h to induce oxidative injury. The cells in the ginsenosideRg1 group were treated with 10µM ginsenosideRg1 for 24h, followed by H2O2 treatment. The cells in the Akt pathway blockage group were treated with 25µM LY294002 for 1h, followed by ginsenosideRg1+H2O2 treatment. The cell counting kit-8 assay was performed to determine cell viability. Cell apoptosis was detected by flow cytometry and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. The results of flow cytometry and TUNEL staining indicated that the apoptotic rate of the H2O2 model group was significantly higher compared with that of the control group. Following the ginsenosideRg1 pretreatment, the apoptotic rate was significantly reduced. In the Akt pathway blockage group, no significant alterations in the levels of cell apoptosis were observed compared with the H2O2 model group. Western blot analysis demonstrated that the ginsenosideRg1 group had a significant downregulation of Bax and cleaved caspase‑3 and an upregulation of Bcl‑2 and phosphorylated Akt protein expression levels compared with the H2O2 model group and the Akt pathway blockage group. In conclusion, ginsenosideRg1 had a protective effect against the H2O2‑induced oxidative stress of rBMSCs, and the specific mechanism may be associated with the activation of the PI3K/Akt pathway by ginsenosideRg1.

A rapid, micro-scale preliminary screening method for active components in Galangal with protective effect against hydrogen peroxide induced cell apoptosis through “thin layer chromatography” and “tetrazolium-based colorimetric assay” array correspondence

A new method has been established for rapid preliminary screening active ingredients in natural products through thin layer chromatography (TLC) array responding with tetrazolium-based colorimetric assay (MTT assay) along with post LC-MS in micro-scale. The extract of the natural product was first separated by TLC. The separated spots obtained from TLC were visualized in situ with vanillin-ethanolic sulfuric acid agent to define the array correspondence between TLC spots and 384-cell culture plate for MTT cell viability assay. The TLC spots from the replicate TLC plates were then eluted and transferred into the wells of 384-cell culture plates according to the array respondence. The TLC spots with significant antioxidant activities were further screened by MTT assay, and subsequently traced and identified by LC-MS based on the TLC-MTT assay array correspondence. This new method was successfully applied to screen active ingredients in a Chinese medicine known as Galangal. Two major inhibitors for the decline of PC12 cell survival (Galangin, m/z 269.1, and 5-hydroxy-7-(4′-hydroxy-3′-methoxyphenyl)-1-phenyl-3-heptanone, m/z 327.2) were effectively screened and identified by this method.

Actovegin reduces the hydrogen peroxide-induced cell apoptosis of SK-N-SH neuroblastoma by means of p38MAPK and PI-3K inhibition.

Actovegin reduces the hydrogen peroxide-induced cell apoptosis of SK-N-SH neuroblastoma by means of p38MAPK and PI-3K inhibition.

Hempseed protein derived antioxidative peptides: Purification, identification and protection from hydrogen peroxide-induced apoptosis in PC12 cells

Hempseeds have not been utilised to any significant extent by the industrial food markets. A novel antioxidant peptide derived from hempseed by-product was investigated. Hempseed protein isolate was prepared by alkaline extraction and subsequent isoelectric precipitation. Its enzymatic hydrolysate, obtained by Alcalase® treatment, was subjected to DA201-C macroporous absorption resin, with simultaneous desalting and concentrating of hydrophobic fragments with improved free radical-scavenging activities. The active fraction was further separated by gel filtration and reversed-phase high performance liquid chromatography to obtain two purified peptides; the peptides were characterised as NHAV and HVRETALV, by MALDI-TOF/TOF MS/MS. The protective effects of the purified peptides on hydrogen peroxide-induced cell apoptosis were investigated in rat pheochromocytoma line PC12 cells. The peptides, at a concentration of 10 μg/ml, possessed protective effects ( P < 0.05) against cell death and oxidative apoptosis. The findings are significant for the discovery and development of natural antioxidants from hempseed by-products.

Selenite suppresses hydrogen peroxide-induced cell apoptosis through inhibition of ASK1/JNK and activation of PI3-K/Akt pathways.

The relationship between selenium and signal molecules has not been well elucidated. It was found that physiological concentration of selenite, 3 microM, reduced ASK1 activity and induced PI3-kinase (PI3-K)/Akt pathways in HT1080 cells. Duration of these signal molecules by selenite was much longer than that by growth factors and other stresses. The longer duration time of these signal molecules may be important to maintain normal functions against stresses. Selenite increased cell proliferation through up-regulation of Bcl-2 expression, mitochondrial membrane potential, adenosine triphosphate (ATP) generation, and glucose uptake mediated by PI3-K pathway. High concentration of H2O2 increased an apoptotic signal molecule, ASK1, which resulted in Bcl-2 down-regulation, membrane potential disruption, decreased ATP and glucose uptake, and activation of caspases. However, an antiapoptotic signal molecule, Akt, was activated also by H2O2, but duration of its activation was much shorter. Selenite blocked apoptosis induced by H2O2, which was related to blocking ASK1 and further stimulating PI3-kinase/Akt activities. Selenite blocked mitochondrial membrane potential disruption by 400 mM H2O2. Selenite also blocked caspase-9 and -3 activities and apoptosis induced by 500 microM H2O2, even after mitochondrial membrane potential disruption. These observations demonstrate that selenite increases cell proliferation and maintains cell survival by activating the antiapoptotic signal and blocking the apoptotic signal.

Hydrogen peroxide induces apoptosis of chondrocytes; involvement of calcium ion and extracellular signal-regulated protein kinase.

Recent observations demonstrated that reactive oxygen species facilitate cartilage degradation. We demonstrated that hydrogen peroxide (H2O2) caused inhibition of proteoglycan synthesis, induction of apoptosis and stimulation of extracellular signal-regulated protein kinase (ERK) of the chondrocytes (Inflamm Res 48: 399-403, 1999). To determine whether activation of ERK is involved in the induction of chondrocyte apoptosis, we examined the signal transduction pathways in this hydrogen peroxide induced apoptosis. Bovine articular chondrocytes were cultured. To determine the induction of apoptosis, Annexin V staining and terminal deoxynucleotidyl transferase were used. The activity of caspase-3 was measured using an apopain assay kit. Intracellular Ca2+ imaging was observed after fura2-AM loading. Hydrogen peroxide enhanced annexin V positive apoptotic cells and caspase-3 activity, which is an executor of apoptosis. Hydrogen peroxide also enhanced intracellular Ca2+ and preincubation with the intracellular Ca2+ chelator protected chondrocytes against hydrogen peroxide-induced cell apoptosis, indicating that an increase in the cytosolic Ca2+ plays a decisive role in this action. When ERK activity was blocked with geldanamycin and PD098059, increased apoptosis was evident. Hydrogen peroxide induces chondrocyte apoptosis via Ca2+ signaling, and ERK is involved in these signal transduction pathways.