Protective effects of ginsenoside Rg1 against hydrogen peroxide-induced injury in human neuroblastoma cells

Attenuation of alcohol-induced hepatocyte damage by ginsenoside Rg1 evaluated using atomic force microscopy

Alcoholic liver disease is an important cause of death worldwide. Hepatocyte apoptosis is commonly observed in alcoholic liver disease. In this study, we investigated the effect of ginsenoside Rg1 (G-Rg1), an organic component of ginseng, on the alcohol-induced morphological and biophysical properties of hepatocytes. Human hepatocytes (HL-7702) were treated in vitro with alcohol and G-Rg1. The cell morphology was observed using scanning electron microscopy. Cell height, roughness, adhesion, and elastic modulus were detected using atomic force microscopy. We found that alcohol significantly induced hepatocyte apoptosis, whereas G-Rg1 attenuated the alcohol-induced hepatocyte damage. Scanning electron microscopy revealed that alcohol-induced significant morphological changes in hepatocytes, including decreased cell contraction, roundness, and pseudopods, whereas G-Rg1 inhibited these negative changes. Atomic force microscopy revealed that alcohol increased the cell height and decreased the adhesion and elastic modulus of hepatocytes. Following treatment with G-Rg1, the cell height, adhesion, and elastic modulus of alcohol-injured hepatocytes were all similar to those of normal cells. Thus, G-Rg1 can attenuate the alcohol-induced damage to hepatocytes by modulating the morphology and biomechanics of the cells. RESEARCH HIGHLIGHTS: In this study, the morphological characteristics of hepatocytes were observed using SEM. The changes in hepatocyte three-dimensional images and biomechanical action caused by alcohol and G-Rg1 were examined at the nanoscale using AFM under near-physiological conditions. Alcohol-induced hepatocytes showed abnormal morphology and biophysical properties. G-Rg1 attenuated the alcohol-induced damage to hepatocytes by modulating the morphology and biomechanics of the cells.

Ginsenoside Rg1 improves anti-tumor efficacy of adoptive cell therapy by enhancing T cell effector functions

Adoptive cell therapy (ACT) has emerged with remarkable efficacies for tumor immunotherapy. Chimeric antigen receptor (CAR) T cell therapy, as one of most promising ACTs, has achieved prominent effects in treating malignant hematological tumors. However, the insufficient killing activity and limited persistence of T cells in the immunosuppressive tumor microenvironment limit the further application of ACTs for cancer patients. Many studies have focused on improving cytotoxicity and persistence of T cells to achieve improved therapeutic effects. In this study, we explored the potential function in ACT of ginsenoside Rg1, the main pharmacologically active component of ginseng. We introduced Rg1 during the in vitro activation and expansion phase of T cells, and found that Rg1 treatment upregulated two T cell activation markers, CD69 and CD25, while promoting T cell differentiation towards a mature state. Transcriptome sequencing revealed that Rg1 influenced T cell metabolic reprogramming by strengthening mitochondrial biosynthesis. When co-cultured with tumor cells, Rg1-treated T cells showed stronger cytotoxicity than untreated cells. Moreover, adding Rg1 to the culture endowed CAR-T cells with enhanced anti-tumor efficacy. This study suggests that ginsenoside Rg1 provides a potential approach for improving the anti-tumor efficacy of ACT by enhancing T cell effector functions.

Alfalfa saponins inhibit oxidative stress-induced cell apoptosis through the MAPK signaling pathway

BACKGROUND

Oxidative stress could seriously affect the growth performance of piglets. As natural extracts of Alfalfa (Medicago sativa), alfalfa saponins have been shown to function as antioxidants in piglets in vivo. However, few studies have investigated the effects and mechanism of alfalfa saponins against oxidative stress in piglet cells in vitro. In the current study, piglets' small intestinal epithelial cell line (IPEC-J2) was explored to investigate the protective effects of alfalfa saponins on injured cells induced by H2O2.

METHODS

To investigate the effects and mechanism of alfalfa saponins against oxidative stress in piglet cells, the cell viability, activity of antioxidant enzymes, LDH and the amount of MDA were detected in H2O2-treated cells after the cells were pre-incubated with alfalfa saponins. The mechanism of alfalfa saponins against H2O2-induced oxidative cell damage was explored by detecting the expression of mitochondrial apoptosis-related proteins. Furthermore, the signaling pathway of alfalfa saponins in IPEC-J2 cells under oxidative stress was also investigated.

RESULTS

The results indicated that alfalfa saponins could rescue cell viability, elevate the activity of antioxidant enzymes and down-regulate the activity of LDH and the amount of MDA in H2O2-induced cells.

CONCLUSION

Alfalfa saponins could inhibit oxidative stress-induced cell mitochondrial apoptosis through the MAPK signaling pathway, thereby providing a new method for improving antioxidant stress ability by means of nutritional regulation.

Ginsenosides in central nervous system diseases: Pharmacological actions, mechanisms, and therapeutics

The nervous system is one of the most complex physiological systems, and central nervous system diseases (CNSDs) are serious diseases that affect human health. Ginseng (Panax L.), the root of Panax species, are famous Chinese herbs that have been used for various diseases in China, Japan, and Korea since ancient times, and remain a popular natural medicine used worldwide in modern times. Ginsenosides are the main active components of ginseng, and increasing evidence has demonstrated that ginsenosides can prevent CNSDs, including neurodegenerative diseases, memory and cognitive impairment, cerebral ischemia injury, depression, brain glioma, multiple sclerosis, which has been confirmed in numerous studies. Therefore, this review summarizes the potential pathways by which ginsenosides affect the pathogenesis of CNSDs mainly including antioxidant effects, anti-inflammatory effects, anti-apoptotic effects, and nerve protection, which provides novel ideas for the treatment of CNSDs.

Protective effects of alfalfa saponins on oxidative stress-induced apoptotic cells

As is known, alfalfa saponins can be used as a feed additive in a pig's diet and the addition of alfalfa saponins to a pig's diet could improve its antioxidant capacity. However, the mechanism by which alfalfa saponins exert their antioxidant effects has not been studied. To address this issue, H2O2-induced rat intestinal epithelial cells were used to establish an oxidative stress model to explore the protective mechanism of alfalfa saponins in this study. The results demonstrated that alfalfa saponins could rescue the cell proliferation activity, elevate the amount of antioxidant enzymes and downregulate the release of MDA and LDH in H2O2-induced cells. The antioxidant activity of alfalfa saponins was achieved by restoring GSH homeostasis. Further results demonstrated that alfalfa saponins could inhibit cell apoptosis through activating the MAPK signaling pathway. These results elucidated the mechanism by which alfalfa saponins exert their antioxidant effects and provided a potential strategy for alleviating oxidative stress in monogastric animals.

Antioxidant Effects of Oleuropein on Hydrogen Peroxide-Induced Neuronal Stress- An In Vitro Study

Background

Persistent oxidative stress can lead to chronic inflammation and mediate most chronic diseases including neurological disorders. Oleuropein has been shown to be a potent antioxidant molecule in olive oil leaf having antioxidative properties.

Objective

The aim of this study was to investigate the protective effects of oleuropein against oxidative stress in human glioblastoma cells.

Methods

Human glioblastoma cells (U87) were pretreated with oleuropein (OP) essential oil 10 µM. After 30 minutes, 100 µM H₂O₂ was added to the cells for three hours. Cell survival was quantified by colorimetric MTT assay. Glutathione level, total oxidant capacity, total antioxidant capacity and nitric oxide levels were determined by using specific spectrophotometric methods. The relative gene expression level of iNOS was performed by qRT-PCR method.

Results

According to viability results, the effective concentration of H₂O₂ (100µM) significantly decreased cell viability and oleuropein pretreatment significantly prevented the cell losses. Oleuropein regenerated total antioxidant capacity and glutathione levels decreased by H₂O₂ exposure. In addition, nitric oxide and total oxidant capacity levels were also decreased after administration of oleuropein in treated cells.

Conclusion

Oleuropein was found to have potent antioxidative properties in human glioblastoma cells. However, further studies and validations are needed in order to understand the exact neuroprotective mechanism of oleuropein.

[Effect of hot water extract of Korean ginseng on neuroblastoma cell parthanatos]

OBJECTIVE

To explore the effect of pretreatment of neuroblastoma cells with hot water extract of Korean ginseng on MNNG-induced parthanatos and its mechanism.

METHODS

Neuroblastoma SH-SY5Y cells were pretreated with 1 mg/L hot water extract of Korean ginseng before induction with 250 μmol/L MNNG for 1 h or 4 h. CCK-8 and cell flow cytometry were used to detect cell survival rate. Western blotting was used to detect the changes in poly(ADP-ribose) (PAR) expression in the treated cells. Immunofluorescence assay was used to detect nuclear distribution of apoptosis-inducing factor (AIF), and flow cytometry was used to detect the level of reactive oxygen species (ROS) in the cells.

RESULTS

Compared with the blank control cells, MNNG-treated SH-SY5Y cells showed significantly decreased survival rate as the concentration of MNNG and the stimulation time increased (P < 0.05). Stimulation with MNNG also resulted in significantly increased expression of PAR protein in the cells (P < 0.05). Pretreatment of the cells with hot water extract of Korean ginseng obviously inhibited MNNG-induced cell death and significantly reduced AIF expression and nucleation in the cells (P < 0.05). MNNG stimulation significantly increased ROS level in the cells, which was decreased significantly by pretreatment of the cells with the extract (P < 0.05).

CONCLUSIONS

Pretreatment with hot water extract of Korean ginseng reduces MNNG-induced parthanatos and ROS production in SH-SY5Y cells.

Neuroactivity of naturally occurring proaporphine alkaloid, pronuciferine

Pronuciferine is a naturally occurring proaporphine alkaloid that belongs to isoquinoline alkaloids. The aim of this study is to investigate the neuroactivity of pronuciferine. We assessed the neuroprotective effect of pronuciferine against hydrogen peroxide (H₂ O₂ )-induced apoptosis in human neuronal SH-SY5Y cells. In addition, we measured the effect of pronuciferine on cell metabolites and brain-derived neurotrophic factor (BDNF) level in SH-SY5Y cells. In vitro result shows that pronuciferine at 10 µM significantly (P < .001) increased the proliferation of SH-SY5Y by 45%, and upon H₂ O₂ addition, pronuciferine significantly (P < .001) suppressed neuronal death caused by H₂ O₂ . Gas Chromatography-Mass Spectrometry (GC-MS) metabolomics study revealed that pronuciferine has a high impact on glycine-serine-threonine pathway by changing the intracellular level of serine dimethylglycine, sarcosine, and threonine. Also, pronuciferine increased the intercellular level of aspartic acid, glutamine, and tryptophan. Additionally, pronuciferine significantly (P < .05) increased the intracellular BDNF protein expression at 10 µM. Therefore, pronuciferine is a neuroactive molecule that might act as a neuroprotective agent to prevent apoptosis in neurodegenerative diseases.

Humanin protects cortical neurons from calyculin A-induced neurotoxicities by increasing PP2A activity and SOD

BACKGROUND

Humanin (HN) is an extensive neuroprotective peptide. This study aims to investigate the neuroprotective effects of HN on Calyculin A (CA)-induced neurotoxicities in cortical neurons and the underlying mechanism.

METHODS

CA was added into the cultured cortical neurons to induce neurotoxicity. Cortical neurons were preincubated with HN which plays a protective role. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH), and Calcein-AM were applied to evaluate the neural insults. Caspase 3 signal and Tunnel were performed to test neural apoptosis. Western blot analysis was used to detect the expressions of phosphorylated tau. The corresponding kits were used to measure the contents of malondialdehyde (MDA) and superoxide dismutase (SOD), and the activity of PP2A, respectively.

RESULTS

HN preincubation preserved cell viability, protected the neurons, alleviated oxidative stress, and reserved PP2A activity. It also blocked tau overphosphorylation at Ser199/202, Ser396, and Thr231 sites and protected neurons against CA-induced insults.

CONCLUSION

These results suggest that HN may serve as a potential therapeutic agent to prevent the pathological changes induced by CA via modulating the activity of PP2A and oxidative stress in neurodegenerative diseases.

Neuroprotective Effects of Ginseng Phytochemicals: Recent Perspectives

As our global population ages, the treatment of neurodegenerative diseases is critical to our society. In recent years, researchers have begun to study the role of biologically active chemicals from plants and herbs to gain new inspiration and develop new therapeutic drugs. Ginseng (Panax ginseng C.A. Mey.) is a famous Chinese herbal medicine with a variety of pharmacological activities. It has been used to treat various diseases since ancient times. Extensive research over the years has shown that ginseng has potential as a neuroprotective drug, and its neuroprotective effects can be used to treat and prevent neurological damage or pathologically related diseases (such as Alzheimer's disease, Parkinson's disease, Huntington's disease, depression symptoms, and strokes). Moreover, evidence for the medicinal and health benefits of ginsenoside, its main active ingredient, in the prevention of neurodegenerative diseases is increasing, and current clinical results have not reported any serious adverse reactions to ginseng. Therefore, we briefly review the recent research and development on the beneficial effects and mechanisms of ginseng and its main active ingredient, ginsenoside, in the prevention and treatment of neurodegenerative diseases, hoping to provide some ideas for the discovery and identification of ginseng neuroprotection.

Ginsenoside Rg1 attenuates hepatic insulin resistance induced by high-fat and high-sugar by inhibiting inflammation

Ginsenoside Rg1 is the active ingredient of Chinese herbal medicine ginseng and sanqi, which has remarkable effects on anti-inflammation and anti-diabetes. In this study, we explored the molecular mechanism of ginsenoside Rg1 against diabetes in rat subjected to insulin resistance induced by high-fat and high-sugar (HFHS). Biochemical analysis revealed that ginsenoside Rg1 significantly decreased the serum levels of alanine transaminase, aspartate transaminase, alkaline phosphatase, total cholesterol, triglyceride, low-density lipoprotein and increased the serum levels of high-density lipoprotein, which indicated ginsenoside Rg1 improved the extent of hepatic steatosis. Furthermore, ginsenoside Rg1 suppressed the expression of IL-1β, IL-6,TNF-α,NF-κB and G6Pase, however, p-Akt was up-regulated. These results suggested that ginsenosideRg1 improved insulin resistance through suppressing inflammatory response and glucose output, which may be a potential therapeutic strategy in protecting hepatic steatosis.

Protective Effects and Target Network Analysis of Ginsenoside Rg1 in Cerebral Ischemia and Reperfusion Injury: A Comprehensive Overview of Experimental Studies

Cerebral ischemia-reperfusion is a complicated pathological process. The injury and cascade reactions caused by cerebral ischemia and reperfusion are characterized by high mortality, high recurrence, and high disability. However, only a limited number of antithrombotic drugs, such as recombinant tissue plasminogen activator (r-TPA), aspirin, and heparin, are currently available for ischemic stroke, and its safety concerns is inevitable which associated with reperfusion injury and hemorrhage. Therefore, it is necessary to further explore and examine some potential neuroprotective agents with treatment for cerebral ischemia and reperfusion injury to reduce safety concerns caused by antithrombotic drugs in ischemic stroke. Ginseng Rg1 (G-Rg1) is a saponin composed of natural active ingredients and derived from the roots or stems of Panax notoginseng and ginseng in traditional Chinese medicine. Its pharmacological effects exert remarkable neurotrophic and neuroprotective effects in the central nervous system. To explore and summarize the protective effects and mechanisms of ginsenoside Rg1 against cerebral ischemia and reperfusion injury, we conducted this review, in which we searched the PubMed database to obtain and organize studies concerning the pharmacological effects and mechanisms of ginsenoside Rg1 against cerebral ischemia and reperfusion injury. This study provides a valuable reference and clues for the development of new agents to combat ischemic stroke. Our summarized review and analysis show that the pharmacological effects of and mechanisms underlying ginsenoside Rg1 activity against cerebral ischemia and reperfusion injury mainly involve 4 sets of mechanisms: anti-oxidant activity and associated apoptosis via the Akt, Nrf2/HO-1, PPARγ/HO-1, extracellular regulated protein kinases (ERK), p38, and c-Jun N-terminal kinase (JNK) pathways (or mitochondrial apoptosis pathway) and the caspase-3/ROCK1/MLC pathway; anti-inflammatory and immune stimulatory-related activities that involve apoptosis or necrosis via MAPK pathways (the JNK1/2 + ERK1/2 and PPARγ/HO-1 pathways), endoplasmic reticulum stress (ERS), high mobility group protein1 (HMGB1)-induced TLR2/4/9 and receptor for advanced glycation end products (RAGE) pathways, and the activation of NF-κB; neurological cell cycle, proliferation, differentiation, and regeneration via the MAPK pathways (JNK1/2 + ERK1/2, PI3K-Akt/mTOR, PKB/Akt and HIF-1α/VEGF pathways); and energy metabolism and the regulation of cellular ATP levels, the blood-brain barrier and other effects via N-methyl-D-aspartic acid (NMDA) receptors, ERS, and AMP/AMPK-GLUT pathways. Collectively, these mechanisms result in significant neuroprotective effects against cerebral ischemic injury. These findings will be valuable in that they should further promote the development of candidate drugs and provide more information to support the application of previous findings in stroke clinical trials.

Protective effect of ginsenoside Rg1 on LPS-induced apoptosis of lung epithelial cells

Sepsis-induced acute lung injury (ALI) is a life-threatening medical condition with high mortality and morbidity in the critical care units. Though, it was commonly accepted that inflammation and apoptosis of lung epithelial cells played an essential role in the pathogenesis of ALI, the underlying mechanism remain unknown. In our study, we found that LPS-induced cell apoptosis could be counteracted by elevated cell autophagy. In LPS-treated MLE-12 cells, suppression of autophagy via 3-MA could aggravate LPS-induced apoptosis, while activation of autophagy via Rapamycin could effectively impair the apoptosis of MLE-12 cells induced by LPS. In order to further discover the molecular regulation mechanism between apoptosis and autophagy in LPS-treated MLE-12 cells, we demonstrated that autophagy could induced the expression of Nrf2, followed with the decrease of p-p65. Targeted inhibition of Nrf2 could induce enlarged cell apoptosis via increasing the level of p-p65. In addition, we demonstrated that ginsenoside Rg1 protected MLE-12 cells from LPS-induced apoptosis via augmenting autophagy and inducing the expression of Nrf2. Our data implicates that activation of autophagy and Nrf2 by ginsenoside Rg1 may provide a preventive and therapeutic strategy for ALI.

Streptocyclinones A and B ameliorate Alzheimer's disease pathological processes in vitro

Alzheimer's disease (AD) is a pathology characterized by the abnormal accumulation of amyloid-beta (Aβ) and hyperphosphorylated tau. Oxidative stress and neuroinflammation are also strongly related to this disease. The ability of two new glycosylated angucyclinones, streptocyclinones A and B (1 and 2), isolated from Streptomyces sp to improve AD hallmarks was evaluated. Compounds were able to protect SH-SY5Y neuroblastoma cells from H₂O₂-induced oxidative injury by activating the nuclear factor E2-related factor (Nrf2). Their capacity to modulate neuroinflammation was tested in lipopolysaccharide-activated BV2 microglial cells. Compounds reduced the release of pro-inflammatory factors, inhibited the activation of NFκB and mitogen activated kinases (MAPK), and induced the translocation of Nrf2 to the nucleus of microglial cells. A trans-well co-culture was established to determine the effect of microglia treated with streptocyclinones on the survival of SH-SY5Y cells. The cell viability of neuroblastoma cells increased when the compounds were added to BV2 cells. SH-SY5Y-TMHT441 cells were used to determine the effect of compounds on tau phosphorylation. Both compounds reduced tau hyperphophorylation by targeting MAPK kinases. Moreover, streptocyclinone B (2) was able to inhibit the activity of β-secretase 1 and decrease the release of reactive oxygen species in BV2 cells stimulated with Aβ. With the same co-culture trans-well system, the treatment of Aβ-stimulated microglia with compound 2 augmented the viability of SH-SY5Y-TMHT441 cells. The results presented in this work provide evidences of the multitarget activities displayed by these new Streptomyces compounds, making them good candidates for further studies in the treatment of AD.

Modulation of AβPP and GSK3β by Endoplasmic Reticulum Stress and Involvement in Alzheimer's Disease

Alzheimer's disease (AD) is a dementia disease with neuronal loss and synaptic impairment. This impairment is caused, at least partly, by the generation of two main AD hallmarks, namely the hyperphosphorylated tau protein comprising neurofibrillary tangles and senile plaques containing amyloid-β (Aβ) peptides. The amyloid-β protein precursor (AβPP) and glycogen synthase kinase-3β (GSK3β) are two main proteins associated with AD and are closely correlated with these hallmarks. Recently, both of the proteins were reported to be modulated by endoplasmic reticulum stress (ERS) and are involved in the pathogenesis of AD. The mechanism of ERS plus the modulation of AβPP processing and GSK3β activity by ERS in AD are summarized and explored in this review.

Treatment of glaucomatous optic nerve damage using ginsenoside Rg1 mediated by ultrasound targeted microbubble destruction

The treatment of glaucomatous optic nervedamage using ginsenoside Rg1 mediated by ultrasound targeted microbubbles destruction was evaluated. Thirty healthy New Zealand white rabbits were subjected to injection of 0.3% carbomer solution to establish glaucomatous optic nerve damage model. Rabbits were divided into 5 groups: control group, model group, model group + intravitreal injection of nerve growth factor (NGF) group, model group + intravitreal injection of ginsenoside Rg1 group (Rg1 group), model group + intravitreal injection of ginsenoside Rg1 + ultrasound microbubble group (ultrasound group), model group + ultrasound targeted microbubble destruction (ultrasound group). Intraocular pressures were compared at 1, 2 and 4 weeks after model establishment. Rabbits were sacrificed 4 weeks after model establishment to collect retinal tissue for H&E staining. Histological changes were observed and the retinal thickness was measured. Contents of malondialdehyde (MDA), superoxide dismutase (SOD) and nitric oxide (NO) were measured by ELISA. Intraocular pressure was significantly higher in model group than in control group at 1 week (P<0.05). Intraocular pressure was significantly lower in the ultrasound group than in NGF group and Rg1 group at all time-points (P<0.05). The number of ganglion cells in model group was decreased significantly. Number of nuclear layer cells was significantly reduced. Thickest retina was found in control group and model group was the thinnest (P<0.05). Contents of MDA and NO in model group were significantly higher than those in NCF group and Rg1 group. SOD content in control group was higher than that in ultrasound group and model group (P<0.05). In conclusion, treatment of glaucomatous optic nerve damage using ginsenoside Rg1 mediated by ultrasound targeted microbubble destruction can reduce the level of oxidative stress, relieve intraocular pressure and reduce ganglion cell damage.

Ginsenoside Rg1 protects human renal tubular epithelial cells from lipopolysaccharide-induced apoptosis and inflammation damage

Ginsenoside Rg1, one of the most notable active components of Panax ginseng, has been widely reported to exert anti-inflammatory actions. This study aimed to reveal whether ginsenoside Rg1 also exhibits beneficial roles against lipopolysaccharide (LPS)-induced apoptosis and inflammation in human renal tubular epithelial cells, and to evaluate the potential role of the component on tubulointerstitial nephritis treatment. HK-2 cells were treated with various doses of ginsenoside Rg1 (0, 50, 100, 150, and 200 μM) in the absence or presence of 5 μg/mL LPS. Thereafter, CCK-8 assay, flow cytometry, western blot, migration assay, reactive oxygen species (ROS) assay, and ELISA were carried out to respectively assess cell viability, apoptosis, migration, ROS activity, and the release of inflammatory cytokines. As a result, ginsenoside Rg1 protected HK-2 cells from LPS-induced injury, as cell viability was increased, cell apoptosis was decreased, and the release of MCP-1, IL-1β, IL-6, and TNF-α was reduced. Ginsenoside Rg1 functioned to HK-2 cells in a dose-dependent manner, and the 150 μM dose exhibited the most protective functions. Ginsenoside Rg1 had no significant impact on cell migration and ROS activity, while it alleviated LPS-induced ROS release and migration impairment. Furthermore, the down-regulations of p-PI3K, p-AKT, and up-regulations of PTEN, p-IκBα, p-p65, Bcl-3 induced by LPS were recovered to some extent after ginsenoside Rg1 treatment. In conclusion, ginsenoside Rg1 protects HK-2 cells against LPS-induced inflammation and apoptosis via activation of the PI3K/AKT pathway and suppression of NF-κB pathway.

Influence of hydrogen-occluding-silica on migration and apoptosis in human esophageal cells in vitro

In the last decade, many studies have shown that hydrogen gas or hydrogen water can reduce the levels of reactive oxygen species in the living body. Molecular hydrogen has antioxidant and antiapoptotic effects and a preventive effect on oxidative stress-induced cell death. In the present study, we investigated solidified hydrogen-occluding-silica (H₂-silica) that can release molecular hydrogen into cell culture medium because the use of hydrogen gas has strict handling limitations in hospital and medical facilities and laboratories, owing to its physicochemical characteristics. Human esophageal squamous cell carcinoma (KYSE-70) cells and normal human esophageal epithelial cells (HEEpiCs) were used to investigate the effects of H₂-silica on cell viability and proliferation. Cell migration was examined with wound healing and culture-insert migration assays. The intracellular levels of reactive oxygen species were evaluated with a nitroblue tetrazolium assay. To assess the apoptotic status of the cells, the Bax/Bcl-2 ratio and cleaved caspase-3 were analyzed by western blot. The results showed that KYSE-70 cells and HEEpiCs were generally inhibited by H₂-silica administration, and there was a significant proliferation-inhibitory effect in an H₂-silica concentration-dependent manner compared with the control group (P < 0.05) in KYSE-70. Apoptosis-inducing effect on KYSE-70 cells was observed in 10, 300, 600, and 1,200 ppm H₂-silica, and only 1,200 ppm H₂-silica caused a 2.4-fold increase in apoptosis in HEEpiCs compared with the control group as the index of Bax/Bcl-2. H₂ silica inhibited cell migration in KYSE-70 cells, and high concentrations had a cytotoxic effect on normal cells. These findings should provide insights into the mechanism of inhibition of H₂-silica on human cancer cells in vitro.

Neuroprotective Effect of the Ginsenoside Rg1 on Cerebral Ischemic Injury In Vivo and In Vitro Is Mediated by PPARγ-Regulated Antioxidative and Anti-Inflammatory Pathways

The ginsenoside Rg1 exerts a neuroprotective effect during cerebral ischemia/reperfusion injury. Rg1 has been previously reported to improve PPARγ expression and signaling, consequently enhancing its regulatory processes. Due to PPARγ's role in the suppression of oxidative stress and inflammation, Rg1's PPARγ-normalizing capacity may play a role in the observed neuroprotective action of Rg1 during ischemic brain injury. We utilized a middle cerebral artery ischemia/reperfusion injury model in rats in addition to an oxygen glucose deprivation model in cortical neurons to elucidate the mechanisms underlying the neuroprotective effects of Rg1. We found that Rg1 significantly increased PPARγ expression and reduced multiple indicators of oxidative stress and inflammation. Ultimately, Rg1 treatment improved neurological function and diminished brain edema, indicating that Rg1 may exert its neuroprotective action on cerebral ischemia/reperfusion injury through the activation of PPARγ signaling. In addition, the present findings suggested that Rg1 was a potent PPARγ agonist in that it upregulated PPARγ expression and was inhibited by GW9662, a selective PPARγ antagonist. These findings expand our previous understanding of the molecular basis of the therapeutic action of Rg1 in cerebral ischemic injury, laying the ground work for expanded study and clinical optimization of the compound.

Mycoplasma fermentans deacetylase promotes mammalian cell stress tolerance

Mycoplasma fermentans is a pathogenic bacterium that infects humans and has potential pathogenic roles in respiratory, genital and rheumatoid diseases. NAD⁺-dependent deacetylase is involved in a wide range of pathophysiological processes and our studies have demonstrated that expression of mycoplasmal deacetylase in mammalian cells inhibits proliferation but promotes anti-starvation stress tolerance. Furthermore, mycoplasmal deacetylase is involved in cellular anti-oxidation, which correlates with changes in the proapoptotic proteins BIK, p21 and BIM. Mycoplasmal deacetylase binds to and deacetylates the FOXO3 protein, similar with mammalian SIRT2, and affects expression of the FOXO3 target gene BIM, resulting in inhibition of cell proliferation. Mycoplasmal deacetylase also alters the performance of cells under drug stress. This study expands our understanding of the potential molecular and cellular mechanisms of interaction between mycoplasmas and mammalian cells.